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Itália - o uso de corticóides é o tratamento padrão da distrofia muscular de Duchenne mas ainda não foi estabelecido o momento da introdução da medicação. Neste estudo os autores descrevem o resultado positivo do tratamento com corticoides, iniciado dos 2 aos 4 anos em crianças com Duchenne. Em quatro casos a capacidade de caminhar permaneceu  até os 16 a 18 anos e 3 conseguiam subir escadas. Houve redução da função respiratória em dois pacientes. Os principais efeitos colaterais foram retardo da puberdade e redução da estatura. O que podemos concluir é que o tratamento precoce com corticóides deve ser preconizado. O resumo em inglês pode ser lido abaixo:

(Muscle & Nerve, 2012) EARLY CORTICOSTEROID TREATMENT IN 4 DUCHENNE MUSCULAR DYSTROPHY PATIENTS: 14-YEAR FOLLOW-UP

LUCIANO MERLINI, MONIA GENNARI, ELISABETTA MALASPINA, ILARIA CECCONI, ANNARITA ARMAROLI,
SAVERIO GNUDI, BERIL TALIM, ALESSANDRA FERLINI, ALESSANDRO CICOGNANI, EMILIO FRANZONI - Italy

ABSTRACT: Introduction: Corticosteroid treatment is the standard of care in Duchenne muscular dystrophy (DMD), but the optimal age to initiate treatment and dosage pattern remain a matter of discussion. Methods: We performed a long-term study of alternate-day corticosteroids in five 2- to 4-year-old DMD patients. The primary outcome measure was prolongation of the ability to walk. Results: One patient lost ambulation at age 10. Four patients, aged 16 to 18 were fully ambulant, and 3 of them could still climb stairs. Respiratory function was moderately reduced in 2. Left ventricular ejection fraction was > 45%. Short stature and delayed puberty were the most relevant side effects. Although the negative impact of corticosteroid treatment on growth rate remained their major concern, parents and patients stated that they preferred corticosteroid therapy. Conclusions: Long-term corticosteroid treatment is effective in prolonging function but not in recovering lost function, and its early use seems appropriate.

USA - pesquisadores conseguiram obter em cultura quantidade grande de células tronco embrionárias e IPS células (células adultas transformadas em embrionárias) com potencial miogênico. Inoculdas em camundongos com distrofia muscular estes produziram distrofina e estas células ainda foram identificadas nos animais 11 meses após a aplicação. O resumo e o desenho da pesquisa pode ser visto abaixo:

(Cell Stem Cell, Volume 10, Issue 5, 4 May 2012, Pages 610–619) Human ES- and iPS-Derived Myogenic Progenitors Restore DYSTROPHIN and Improve Contractility upon Transplantation in Dystrophic Mice

Radbod Darabi, Robert W. Arpke, Stefan Irion, John T. Dimos, Marica Grskovic, Michael Kyba,Rita C.R. Perlingeiro - USA

A major obstacle in the application of cell-based therapies for the treatment of neuromuscular disorders is obtaining the appropriate number of stem/progenitor cells to produce effective engraftment. The use of embryonic stem (ES) or induced pluripotent stem (iPS) cells could overcome this hurdle. However, to date, derivation of engraftable skeletal muscle precursors that can restore muscle function from human pluripotent cells has not been achieved. Here we applied conditional expression of PAX7 in human ES/iPS cells to successfully derive large quantities of myogenic precursors, which, upon transplantation into dystrophic muscle, are able to engraft efficiently, producing abundant human-derived DYSTROPHIN-positive myofibers that exhibit superior strength. Importantly, transplanted cells also seed the muscle satellite cell compartment, and engraftment is present over 11 months posttransplant. This study provides the proof of principle for the derivation of functional skeletal myogenic progenitors from human ES/iPS cells and highlights their potential for future therapeutic application in muscular dystrophies.

 

França -  a bradicinina é uma substância endógena com atividade sobre o endotélio dos vasos e sobre as células cardíacas, tendo sido descoberta por um brasileiro. A injeção da bradicinina em cães promoveu uma significativa melhora das alterações cardiovasculares observadas nestes animais. O texto em inglês pode ser lido abaixo:

(Cardiovasc Res, May 2012)  Bradykinin restores left ventricular function, sarcomeric protein phosphorylation and e/nNOs levels in dogs with Duchenne muscular dystrophy cardiomyopathy

Jin Bo Su, Olivier Cazorla, Stéphane Blot, Nicolas Blanchard-Gutton, Younss Ait Mou, Inès Barthélémy, Lucien Sambin, Carolina Carlos Sampedrano, Vassiliki Gouni, Yves Unterfinger, Pablo Aguilar, Jean-Laurent Thibaud, Alain Bizé, Jean-Louis Pouchelon, Hubert Dabiré, Bijan Ghaleh, Alain Berdeaux, Valérie Chetboul, Alain Lacampagne, and Luc Hittinger - France

Aims Cardiomyopathy is a lethal result of Duchenne muscular dystrophy (DMD) but its characteristics remain elusive. The golden retriever muscular dystrophy (GRMD) dogs produce DMD pathology and mirror DMD patient’s symptoms including cardiomyopathy. We previously showed that bradykinin slows the development of pacing-induced heart failure. Therefore, the goals of this research were to characterize dystrophin-deficiency cardiomyopathy and to examine cardiac effects of bradykinin in GRMD dogs

Methods and results At baseline, adult GRMD dogs had reduced fractional shortening (28±2% vs 38±2% in control dogs, p<0.001) and left ventricular (LV) subendocardial dysfunction leading to impaired endo-epicardial gradient of radial systolic velocity (1.3±0.1 cm/s vs 3.8±0.2 cm/s in control dogs, p<0.001) measured by echocardiography. These changes were normalized by bradykinin infusion (1 µg/min, 4 weeks). In isolated permeabilized LV subendocardial cells of GRMD dogs, tension-calcium relationships were shifted downward and force-generating capacity and transmural gradient of myofilament length-dependent activation were impaired compared with control dogs. Concomitantly, phosphorylation of sarcomeric regulatory proteins and levels of endothelial and neuronal nitric oxide synthase in LV myocardium were significantly altered in GRMD dogs. All these abnormalities were normalized in bradykinin-treated GRMD dogs

Conclusions Cardiomyopathy in GRMD dogs is characterized by profound LV subendocardial dysfunction, abnormal sarcomeric protein phosphorylation and impaired endothelial and neuronal nitric oxide synthase, which can be normalized by bradykinin treatment. These data provide new insights into pathophysiological mechanisms accounting for DMD cardiomyopathy and open new therapeutic perspectives.

Canadá -  mesmo em países de primeiro mundo os protocolos de axompanhamento cardíológico em Duchenne não sao seguidos; recomenda-se pelo uma avaliação cardiológica anual. Numa avaliação no Canadá estudando 32 pacientes com Duchenne apenas 19 haviam passado por esta avaliação e somente 22 haviam feito o ecocardiograma. Provavelmente no Brasil o número de pessoas sem estas avaliações seria maior. O texto em inglës do trabalho pode ser lido abaixo:

(B47 INTENSIVE CARE UNIT PHYSIOTHERAPY AND WEANING: MIND OVER MUSCLE?) Audit Of The Cardiac Management Of Patients With Duchenne Muscular Dystrophy On Ventilatory Support

 L. O'Brien , M. Avendano , R. Goldstein , R. A. Evans - Canada

Introduction. The life expectancy of patients with Duchenne Muscular Dystrophy (DMD) has increased, from the 2 decade to the 5 decade, in part due to improved ventilatory support. However, cardiomyopathy is common and is projected to increase as a cause of death. Current international guidelines recommend an annual assessment of cardiac function in adult patients with DMD and initiation of appropriate pharmacological treatment (1). We conducted an audit of the current cardiac management of patients with DMD with respiratory failure under the care of West Park Healthcare Centre, Toronto, Canada.
Methods: We reviewed the medical charts of patients with DMD requiring ventilatory support. Patients were included if they had respiratory follow up within the last three years and were alive at the time of the audit. Patient demographics and ventilatory status were recorded. Cardiac management was recorded including date of the last documented electrocardiogram (ECG), echocardiogram (ECHO), cardiology review and pharmacological management. The ECG and ECHO reports were reviewed.
Results: 32 patients with DMD (31 male, mean [SD] age 31 [7] yrs) met the inclusion criteria and their medical notes were retrieved. 7/32 patients were living in a chronic assisted ventilation unit and 25/32 were cared for at home. 18/32 required continuous ventilation and 14/32 required nocturnal ventilation only. 17/32 patients were ventilated via a tracheostomy. 10/32 and 6/32 patients had a documented ECG and ECHO respectively, within the last year. 26/32, 22/32, and19/32 patients had previous documentation of an ECG, ECHO, and had been assessed by a cardiologist, respectively. Out of the available results, 21/25 patients had an abnormal ECG and 15/20 patients had demonstrable left ventricular dysfunction (Grade II: 6, Grade III: 7, Grade IV: 2). 16/32 were prescribed either an Angiotensin Converting Enzyme inhibitor or an Angiotensin Receptor Blocker, 11/32 were prescribed Beta-Blockers, 4/32 were prescribed digoxin and 1/32 was prescribed spironolactone.
Conclusions: Although cardiac function had been assessed in over two thirds of patients with DMD, few were undergoing annual cardiac assessments. A new policy of closer monitoring is suggested with a repeat audit in two years. This audit highlights the need for respiratory physicians to refer these patients for annual cardiology review in line with current guidance.
(1) Bushby K et al. Lancet Neurol 2010; 9(1):77-93

Israel -  losartan é uma droga utilizada em hipertensão arterial; estudos com camundongos com modelo de distrofia muscular de Duchenne já demostraram efeito positivo da droga na musculatura esquelética. Nesta pesquisa com camundongos portadores de distrofia muscular congënita houve significativa melhora tanto da força muscular quanto das alterações patológicas e redução dos mediadores de fibrose nos músculos.  

USA - neste encontro serão apresentadas mais de 17 pesquisas que se relacionam com o tratamento das distrofias musculares, sendo todos os experimentos ainda em animais mas com perspectivas de uso em seres humanos.

Itália - a cardiomiopatia da distrofia muscular de Duchenne é ao lado da insuficiência respiratória a principal causa de mortalidade da doença. Neste relato os autores trataram dois pacientes com Duchenne e que apresentaram cardiomiopatia grave com um equipamento de assistëncia da função ventricular esquerda. O equipamento é implantado em paralelo com o coração. O resultado do tratamento a longo prazo foi bom permitindo a manutenção da qualidade de vida e retorno para as atividades diárias.

USA -  trata-se de um artigo de revisão de estudos já realizados em humanos e animais sobre a realização de exercícios físicos na distrofia muscular. A literatura não é concordante sobre o tema. Há benefícios descritos sobre as vantagens dos exercícios mas não há consenso quanto ao tipo e quantidade necessária.

USA - neste congresso americano de pesquisas experimentais serão apresentadas mais de 30 trabalhos relacionados com distrofia muscular, sendo que as 10 abaixo são as que tem maior relação com o tratamento da doença. Há pesquisas sobre o uso de suplementos como resveratrol e quercetina, pesquisas com o uso de vetor viral diretamente no diafragma de camundongos, com o uso de antioxidantes como a acetilcisteína, com o uso de anti-inflamatórios doadores de óxido nítrico como o flurbiprofen e com o uso de inibidores da fosfodiesterase (drogas habitualmente usadas na disfunção erétil). O sresumos dos trabalhos em inglês pode ser lido abaixo:

1)   Acute phosphodiesterase inhibition improves functional muscle ischemia in patients with Becker muscular dystrophy

Elizabeth Anne Martin1, Ashley E Walker1, Bryan L Scott1, Teresa C Malott1, Nirmal Singh1, Swaminatha V Gurudevan1, Jimmy Johannes1, Robert M Elashoff2, Gail D Thomas1 and Ronald G Victor1

1 The Heart Institute, Cedars Sinai Medical Center, Los Angeles, CA
2 Biomathematics, UCLA, Los Angeles, CA

oss of sarcolemmal nitric oxide synthase (nNOS) engenders ischemia of exercising dystrophin-deficient muscles of mdx mice and boys with Duchenne muscular dystrophy. We tested if muscle ischemia also occurs in Becker muscular dystrophy (BMD), a milder disease often caused by dystrophin mutations involving the nNOS binding site, and is improved by tadalafil, a phosphodiesterase (PDE5A) inhibitor that enhances cGMP/NO signaling. We measured reflex vasoconstriction (decreased forearm muscle oxygenation [{Delta}Hb02, near infrared spectroscopy] during lower body negative pressure [LBNP]) at rest and during rhythmic handgrip (HG) in 5 male controls (Ctrls) and 10 men with BMD who underwent a placebo-controlled cross-over trial of single-dose (20 mg) tadalafil. At baseline, HG greatly attenuated vasoconstriction in Ctrls ({Delta}Hb02:–393±89 vs. –91±40 units, p<.01; rest vs. HG) but caused no attenuation in BMD (–381±45 vs. – 374±46). Tadalafil markedly improved ischemia in BMD ({Delta}Hb02:– 439±70 vs. –230±54, rest vs. HG; p=0.014) whereas placebo had no effect. These data provide the first evidence in man that PDE5A inhibition can improve blood flow regulation in dystrophin-deficient skeletal muscle. Funded by MDA 201149.

2)  Early Anatomical Identification Markers for Duchenne Muscular Dystrophy in a Subadult Subject

Jasmine H. Harris1, Ellen Godwin2 and Samuel Marquez3

1 College of Medicine, SUNY Downstate Medical Center, Brooklyn, NY
2 Department of Orthopaedic Surgery & Rehabilitation Medicine, SUNY Downstate Medical Center, Brooklyn, NY
3 Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY

Duchenne Muscular Dystrophy (DMD) readily affects gait and posture in subadult populations afflicted with the disease. This study used instrumented motion analysis (IMA) to identify how gait and posture changes respond to DMD disease. 3-D motion analysis was performed with the Vicon Motion Capture System on a 5-year-old boy suspected with DMD. Thirty-nine reflective markers were placed on specific anatomical landmarks according to the Plug-in-Gait Model used with the Vicon system. The child walked across the 25 feet gait analysis laboratory for 10 trials. A single representative trial was selected for analysis. Kinematic parameters of gait were compared to those of a typically developing child. IMA identified specific changes in joint kinematics in the child with DMD as compared to the typically developing child. Changes include: increase in anterior pelvic tilt and hip flexion in swing, genu recurvatum in stance, plantar flexion on initial contact with ground, and lack of dorsiflexion in swing. These gait deviations are commonly found in boys with DMD. The results show the ability to identify these changes translating in the early diagnosis of DMD as they represent a specific pattern of walking that is related to the progression of weakness observed. Identification of anatomical gait deviations can assist in the development of treatment interventions to assist the child to be ambulant as long as possible.

3) Resveratrol decreases inflammation and oxidative stress in the mdx mouse model of duchenne muscular dystrophy

Bradley Scott Gordon, Patti Weed, Emily Learner, Drew Schoenling and Matthew C Kostek

Exercise Science, University of South Carolina, Columbia, SC

Duchenne Muscular Dystrophy (DMD) is a genetic disease characterized by muscle damage, oxidative stress, chronic inflammation, and fibrosis. Resveratrol (RES) is an antioxidant and anti-inflammatory. We have shown that RES improves muscle function in the mdx mouse model of DMD, and others have shown resveratrol decreases fibrosis and oxidative stress in older mdx mice. However, its effect on pathology in young mdx mice is unknown. The purpose of this study was to investigate the effect of resveratrol on muscle pathology in young mdx mice. RES (100 mg/kg) or vehicle was administered to 4–5 week old mdx mice everyday for 10 days or every other day for 8 weeks. Muscle fiber integrity, inflammation, and oxidative stress were assessed by H&E staining and 4-HNE content. Total inflammation was reduced 21 ± 6% (p < 0.05) after 10 days of treatment with no change in oxidative stress. After 8 weeks of RES treatment, centrally located nuclei were reduced 12 ± 4% (p < 0.05), oxidative stress measured through 4-HNE content decreased 2 ± 0.13 fold (p < 0.05), and total inflammation and fibrosis did not change. We conclude that RES enhances muscle membrane integrity by reducing inflammation during the peak pathological period and long term oxidative stress. Therefore, resveratrol could be a treatment for boys with DMD. This project was funded by The Center for Alternative Medicine at The University of South Carolina School of Medicine.

4) Mdx mice have a defect in autophagy that is restored by rapamycin-loaded nanoparticle treatment

Allison Jinquan Li1, Kristin P. Bibee1, Jon N. Marsh1, Conrad C. Weihl2 and Samuel A. Wickline1

1 Department of Medicine, Division of Cardiology, Washington University in St. Louis, St. Louis, MO
2 Department of Neurology, Washington University in St. Louis, St. Louis, MO

Duchenne Muscular Dystrophy (DMD) is genetic disorder caused by mutations in dystrophin, a cytoskeletal protein in muscles, leading to progressive muscle wasting and ultimately death in the second or third decade of life. The current standard of care for DMD patients is corticosteroid therapy which slows down the natural progression of the disease but causes unwanted side effects. Our lab’s previous studies of therapeutics in an in vivo DMD model has demonstrated that mdx mice treated with rapamycin-loaded nanoparticles showed an increase in strength that was not observed with oral rapamycin treatment. Because rapamycin is known to induce autophagy, we assayed for autophagy in mdx mice treated with rapamycin-loaded nanoparticles. Western blot analysis of LC3B-II, the processed form of a protein used in autophagy, suggests that there is a previously unknown defect in autophagy in mdx mice, as shown by a lack of LC3 3B-II accumulation after blockade of autophagic flux by colchicine (Fig. 1A). Rapamycin nanoparticle treatment rescues autophagy to levels comparable to the control (Fig. 1B), suggesting that defective autophagy may contribute to the physical manifestations of muscular dystrophy in mdx mice and that restoration to normal levels may lead to the observed strength increase. Supported by NIH grant (R01 AR056223 to S.A.W.)

5)  Acute phosphodiesterase inhibition ameliorates functional muscle ischemia in dystrophin-deficient mdx mice

Liang Li, Ronald G Victor and Gail D Thomas

The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA

We previously have shown that the loss of sarcolemmal nitric oxide synthase (nNOS) in the dystrophin-deficient muscles of mdx mice and boys with Duchenne muscular dystrophy (DMD) renders the diseased muscles susceptible to ischemia during exercise. We now are extending this finding to men with Becker muscular dystrophy (BMD). We therefore hypothesized that treatment with a phosphodiesterase (PDE) inhibitor to reduce cGMP breakdown and enhance the NO signal from residual nNOS would prevent functional muscle ischemia. To test this, we compared norepinephrine (NE)-mediated vasoconstriction in resting and contracting hindlimbs of mdx mice after acute treatment with vehicle or a PDE inhibitor (tadalafil, 8 mg/kg; zaprinast, 4 mg/kg). In vehicle-treated mice, the usual effect of muscle contraction to attenuate NE-mediated vasoconstriction was impaired as shown by similar decreases in femoral vascular conductance in contracting vs resting hindlimbs (attenuation ratio = 0.87 ± 0.11; n = 10). NE-induced ischemia in the contracting hindlimbs was partially reversed in mice treated with the selective PDE5A inhibitor tadalafil (0.61 ± 0.06; n = 6; P < 0.05 vs vehicle) or the nonselective PDE inhibitor zaprinast (0.46 ± 0.10; n = 7; P < 0.05 vs vehicle). The effect of PDE inhibition to ameliorate functional muscle ischemia in mdx mice suggests a novel potential use for the treatment of DMD/BMD patients. Supported by MDA, 201149.

6) Dietary quercetin supplementation alleviates disease related muscle injury in dystrophic muscle

Katrin Hollinger1, Elizabeth Snella1, R. Andrew Shanely2 and Joshua T. Selsby1

1 Animal Science, Iowa State University, Ames, IA
2 Human Performance Laboratory; North Carolina Research Campus, Appalachian State University, Kannapolis, NC

Duchenne muscular dystrophy is the most common, fatal, X-linked muscle disease and is modeled by the mdx mouse. Dystrophic muscle shows signs of progressive necrosis and fibrosis leading to a loss of muscle function. Peroxisome proliferator-activated receptor {gamma}coactivator-1α (PGC-1α) up-regulation has been shown to alleviate some aspects of dystrophic pathology. Quercetin (QCN), a natural polyphenolic compound derived from foods such as red apples and red onions, is a potent sirtuin 1 (SIRT1) activator capable of entering muscle cells via oral delivery. SIRT1, in turn, activates PGC-1α by deacetylation. To determine the extent to which a diet containing QCN could alter the progression of disease related muscle injury 3 mo old mdx mice were fed a diet containing 0% or 0.2% QCN for 6 mo, sacrificed, and diaphragms removed. Control and treated mice ate similar amounts of food and grew at a similar rate during the study period. Dietary QCN reduced the number of extracellular nuclei/mm2 by 37% (p<0.05). The number of muscle cells/mm2 was increased by 20% (p<0.05) and muscle cells with centralized nuclei were reduced by 33% (p<0.05) in diaphragms from treated animals compared to control. Fibrosis was similar between groups. These data suggest that dietary QCN is beneficial to dystrophic muscle and warrants greater exploration as a potential therapeutic agent. Partially supported by the Martin Fund.

7) PCG-1 alpha over-expression rescues dystrophic muscle by modifying gene expression

Katrin Hollinger, Drance Rice, Elizabeth Snella and Joshua T Selsby

Animal Science, Iowa State University, Ames, IA

Duchenne muscular dystrophy is caused by the inability to produce a functional dystrophin protein. Typically, diagnosis is in the preschool years due to locomotor deficits, indicating muscles have already been damaged by the disease. Thus, it is critical that treatments be able to rescue muscle from further deterioration. We have shown that Peroxisome proliferator-activated receptor {gamma}coactivator-1α (PGC-1α) gene transfer rescues dystrophic muscle from disease related decline. To better understand the mechanism underlying the benefits of PGC-1α over expression, 3 wk old mdx mice were injected in one hind limb with null AAV6 (empty capsid) and in the other with an AAV6 driving expression of PGC-1α. At six weeks of age solei were collected. Utrophin protein expression was measured by immunohistochemistry and was increased nearly 3-fold (p<0.05) in PGC-1α over-expressing limbs compared to control limbs. PCR arrays were performed to identify genes regulated by PGC-1α over-expression. In the PGC-1α treated soleus expression of genes associated with the dystrophinglycoprotein complex (DGC) were increased by 40–92% (p<0.05), oxidative metabolism by 35–87% (p<0.05), muscle repair by 56–92% (p<0.05), and structural components by 20–300% (p<0.05). These data indicate that PGC-1α-mediated rescue of dystrophic muscle is accomplished through numerous contributing mechanisms. Partially supported by CIAG.

8) The effect of N-acetylcysteine on contractile function and protein-thiol oxidation in skeletal muscles of mdx mice

Gavin Jon Pinniger1, Evanna Binti Assan1, Jessica Terrill2 and Peter Arthur3

1 Physiology, University of Western Australia, Crawley, Australia
2 Anatomy and Human Biology, University of Western Australia, Crawley, Australia
3 Biochemistry, University of Western Australia, Crawley, Australia

Duchenne Muscular Dystrophy (DMD) is a fatal X-linked recessive disease characterized by severe muscle weakness. We hypothesized that oxidation of skeletal muscle proteins such as myosin contributes to dystrophic muscle weakness seen in DMD boys and dystrophic mdx mice and that this muscle weakness will be attenuated by treatment with the antioxidant N-acetylcysteine (NAC). Six week old mdx mice and non-dystrophic, C57 mice were treated with 2% NAC in drinking water for six weeks and compared to untreated mdx and C57 mice. Grip strength and body weight were measured weekly during the treatment period. After six weeks of treatment, the 12 week old mice were anaesthetized (sodium pentobarbitone; 40 mg/kg; IP) and the extensor digitorum longus (EDL) muscles were excised for analysis of contractile function and protein thiol-oxidation. n mdx mice, NAC treatment significantly increased normalized grip strength and maximum specific force in isolated EDL muscles (NAC = 13.1 ± 1.2 N/cm2; Untreated = 9.8 ± 0.8 N/cm2, p<0.05), and significantly reduced myosin protein-thiol oxidation (NAC = 10.6 ± 0.8 %; Untreated = 13.7 ± 0.8 %, p<0.05). In non-dystrophic C57 mice, NAC treatment significantly increased normalized grip strength by 36%, but had no significant effect on maximum specific force or myosin protein-thiol oxidation in EDL muscles.

9) Treatment with a nitric oxide-donating NSAID counteracts functional muscle ischemia in dystrophin-deficient mdx mice

Gail D Thomas1, Angela Monopoli2, Claudio De Nardi2, Ennio Ongini2 and Ronald G Victor1

1 The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
2 NicOx Research Institute, Bresso, Italy

he dystrophin-deficient muscles of boys with Duchenne muscular dystrophy (DMD) and mdx mice, a model of DMD, are susceptible to ischemia during exercise due to loss of neuronal nitric oxide synthase (nNOS) from the sarcolemma. We hypothesized that treatment with a NO-donating drug would compensate for nNOS deficiency and counteract functional muscle ischemia. We fed mdx mice a standard diet containing 1% soybean oil (vehicle) or a low (15 mg/kg) or high (45 mg/kg) dose of a NO-releasing derivative of the NSAID flurbiprofen (n = 12/group). After 1 month of treatment, we compared vasoconstrictor responses to intra-arterial norepinephrine (NE) in resting and contracting hindlimbs. In vehicle-treated mice, the usual effect of muscle contraction to attenuate NE-mediated vasoconstriction was impaired as shown by similar decreases in femoral vascular conductance in contracting vs resting hindlimbs (attenuation ratio = 0.88 ± 0.03). NE-induced ischemia was also seen in the contracting hindlimbs of mice treated with low dose drug (0.92 ± 0.04; P > 0.05 vs vehicle), but was markedly attenuated in mice treated with high dose drug (0.22 ± 0.03; P < 0.05 vs vehicle or low dose). The beneficial effect of the high dose was maintained with treatment up to 3 months. These data demonstrate a robust anti-ischemic effect of a NO-donating drug in mdx mice and suggest a potential use in the treatment of DMD patients. Supported by NicOx, 801130.

10)  Administration of recombinant adeno-associated virus vector to the diaphragm through direct intramuscular injection

Ashley J Smuder1, Darin J Falk2, W Bradley Nelson1 and Scott K Powers1

1 Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
2 Department of Pediatrics, University of Florida, Gainesville, FL

Ventilatory insufficiency due to impaired diaphragm function is the leading cause of morbidity and mortality in many conditions (e.g. muscular dystrophy). Currently, pharmacological inhibitors and genetically modified animals are used to study many diseases affecting the diaphragm. However, these methodologies are problematic due to the occurrence of off-target effects and possible consequences of life-long genetic alterations. Further, conventional approaches to gene transfection (i.e., plasmid injection and electroporation) are not possible due to the size and location of the diaphragm and thus alternative methods are needed to alter gene expression. Therefore, we have developed a method for the delivery of recombinant adeno-associated virus vectors (rAAV) to the rat diaphragm via direct intramuscular injection. We hypothesized that by directly injecting rAAV we could selectively target diaphragm muscle fibers and establish a novel animal model for studying signaling pathways and also provide a strategy for effectively using gene therapy to rescue the diaphragm in disease states. Our results demonstrate that the morphology of the rat diaphragm is sufficient to allow direct injection and provide support for the use of rAAV as an intervention to study the diaphragm during conditions that promote diaphragm dysfunction.

USA - Eteplirsen  é o oligonucleotídeo desenvolvido pela AVi para salto do exon 51. No estudo parcial de 24 semanas os pesquisadores observaram aumento significante da expressão da distrofina no músculo. No entanto a força muscular não apresentou alteração significativa com o tratamento de 24 semanas. Os estudos prosseguem para avaliação de longo prazo do tratamento.

Australia - pesquisadores indentificaram em camundongos uma proteína HSP72 que contribui para a melhora da distrofia muscular. No experimento os animais receberam a droga BGP-15 que aumenta a HSP72 e os animais apresentaram melhor força muscular, redução das alterações patológicas e aumento da sobrevida.

USA - camundongos deficientes em laminina alfa 2, um modelo experimental de distrofia congênita merosina negativa, foram tratados por via sistêmica com laminina-111. Os animais tratados apresentaram um espetacular aumento da sobrevida, aumento da força muscular e reduçâo das alterações patológicas nos músculos. O resumo em inglês pode ser lido abaixo:

(The American Journal of Pathology, Volume 180, Issue 4, April 2012, Pages 1593-1602) Laminin-111 Protein Therapy Reduces Muscle Pathology and Improves Viability of a Mouse Model of Merosin-Deficient Congenital Muscular Dystrophy

Jachinta E. Rooney, Jolie R. Knapp, Bradley L. Hodges, Ryan D. Wuebbles, Dean J. Burkin

Merosin-deficient congenital muscular dystrophy type 1A (MDC1A) is a lethal muscle-wasting disease that is caused by mutations in the LAMA2 gene, resulting in the loss of laminin-α2 protein. MDC1A patients exhibit severe muscle weakness from birth, are confined to a wheelchair, require ventilator assistance, and have reduced life expectancy. There are currently no effective treatments or cures for MDC1A. Laminin-α2 is required for the formation of heterotrimeric laminin-211 (ie, α2, β1, and γ1) and laminin-221 (ie, α2, β2, and γ1), which are major constituents of skeletal muscle basal lamina. Laminin-111 (ie, α1, β1, and γ1) is the predominant laminin isoform in embryonic skeletal muscle and supports normal skeletal muscle development in laminin-α2–deficient muscle but is absent from adult skeletal muscle. In this study, we determined whether treatment with Engelbreth-Holm-Swarm–derived mouse laminin-111 protein could rescue MDC1A in the dyW−/− mouse model. We demonstrate that laminin-111 protein systemically delivered to the muscles of laminin-α2–deficient mice prevents muscle pathology, improves muscle strength, and dramatically increases life expectancy. Laminin-111 also prevented apoptosis in laminin-α2–deficient mouse muscle and primary human MDC1A myogenic cells, which indicates a conserved mechanism of action and cross-reactivity between species. Our results demonstrate that laminin-111 can serve as an effective protein substitution therapy for the treatment of muscular dystrophy in the dyW−/− mouse model and establish the potential for its use in the treatment of MDC1A.

Canada - 22 pacientes com Duchenne foram submetidos a avaliação da função respiratória por 45 meses após a introdução da manobra do empilhamento de ar; os resultados foram comparados com os resultados obtidos nos 33 meses anteriores ao estudo. A perda de função pulmonar reduziu-se drasticamente com a introdução da manobra de empilhamento de ar.

USA - o teste do pezinho é obrigatório no Brasil parta identificação de algumas doenças genéticas ou congênitas; através de uma amostra seca de sangue faz se uma triagem para várias doenças. Há autores que preconizam a introdução da dosagem da CK para triagem da doença, enquanto outros acham que enquanto não houver tratamento definitivo este diagnóstico precoce não seria desejável. Esta pesquisa envolveu um grande número de recém-nascidos que foram submetidos a dosagem da CK completada com estudo genético quando a CK estava alterada. Em três casos o diagnóstico de distrofia muscular de Duchenne foi realizado e em outros 3 casos o diagnóstico foi de distrofia tipo cinturas. Este estudo demonstra a viabilidade de diagnóstico precoce de distrofias musculares incluindo a dosagem de CK no teste do pezinho. O resumo em inglês pode ser lido abaixo:

(Annals of Neurology, 2012) Evidence Based Path to Newborn Screening for Duchenne Muscular Dystrophy

Jerry R Mendell, Chris Shilling, Nancy D. Leslie,  Kevin M Flanigan, Roula al-Dahhak,  Julie Gastier-Foster,  Kelley
Kneile, Diane M. Dunn,  Brett Duval, Alexander Aoyagi, Cindy Hamil, Maha Mahmoud, Kandice Roush,  Lauren Bird,
Chelsea Rankin, Heather Lilly,  Natalie Street, MS, Ram Chandrasekar,  Robert B. Weiss - USA

Background: Creatine kinase (CK) levels are increased on dried blood spots in newborns related to the birthing process. As a marker for newborn screening, CK in Duchenne muscular dystrophy (DMD) results in false-positive testing. In this report we introduced a two-tier system using the dried blood spot to first assess CK with follow up DMD gene testing.
Methods: A fluorometric assay based upon the enzymatic transphosphorylation of ADP to ATP was used to measure CK activity. Preliminary studies established a population-based range of CK in newborns using 30,547 de-identified anonymous dried blood spot samples. Mutation analysis used genomic DNA extracted from the dried blood spot  followed by whole genome amplification with assessment of single/multi-exon deletions/duplications in the DMD gene using multiplex ligation-dependent probe amplification.
Results: DMD gene mutations (all exonic deletions) were found in six of 37,649 newborn male subjects, all of whom had CK levels > 2000 U/L. In three newborns with CK >2000 U/L in whom DMD gene abnormalities were not found, we identified limb-girdle muscular dystrophy gene mutations affecting DYSF, SGCB, and FKRP.
Conclusions: A two-tier system of analysis for newborn screening for DMD has been established. This path for newborn screening fits our health care system, minimizes false-positive testing, and uses predetermined levels of CK on dried blood spots to predict DMD gene mutations.

Australia - existem inúmeras pesquisas prévias com o IGF-1 em modelos de distrofia muscular; nesta pesquisa os autores testaram em dois modelos de distrofia o IGF-1 peguilato que tem um efeito mais prolongado; no modelo de distrofia com menor grau de lesão muscular os autores observaram um efeito benéfico que não foi observado nos camundongos com a forma de distrofia mais grave; o seu uso poderia ser útil nas formas iniciais da doença ou quando houvesse algum grau de lesão aguda dos músculos, por trauma por exemplo. O resumo em inglês pode ser lido abaixo:

(Growth Hormone & IGF Research, 2012) Therapeutic potential of PEGylated insulin-like growth factor I for skeletal muscle disease evaluated in two murine models of muscular dystrophy

Stefan M. Gehrig,  Chris van der Poela, Andreas Hoeflich, Timur Naim, Gordon S. Lynch, Friedrich Metzger - Australia

Objective: Duchenne muscular dystrophy (DMD) is a fatal monogenetic disease with affected males displaying severe and progressive muscle wasting and weakness eventually leading to premature death. Possible therapeutic benefits of insulin-like growth factor I (IGF-I) have been studied extensively in various models of muscle disease and DMD with IGF-I as a mediator of improved skeletal muscle regeneration by enhancing myoblast proliferation and differentiation.
Design: We tested the efficacy of a novel IGF-I analogue, a polyethylene glycol modified IGF-I (PEG-IGF-I), to ameliorate the pathophysiology of muscular dystrophy in two mouse models of DMD. We used mdx mice which lack dystrophin (as in DMD) but exhibit only a relatively mild phenotype, and the dko mouse which is a transgenic model lacking utrophin in addition to dystrophin, and which exhibits a more severe, lethal phenotype like that in DMD.
Results: In young mdx mice, twice-weekly PEG-IGF-I s.c. injections for 6 weeks protected the diaphragm muscle against fatigue and the tibialis anterior (TA) muscle against contraction-induced injury. However, this beneficial effect of PEG-IGF-I was less pronounced in mdx mice when treatment was initiated later in adulthood. In severely affected dko mice PEG-IGF-I treatment did not affect pathophysiological parameters including animal survival.
Conclusions: These data suggest a therapeutic benefit with PEG-IGF-I treatment only in mild muscle pathologies, since its potential to ameliorate the pathophysiology in models of severe muscular dystrophies was limited. Treatment should be initiated only for mild muscle pathologies if functional benefits are to be realised and therefore may be relevant as a short-term therapy to hasten the functional repair of otherwise healthy muscles after injury.

 

 

Holanda -  os autores compararam o peso e altura das crianças com distrofia muscular de Duchenne sem tratamento com as tratadas com prednisona no esquema 10 dias com/10 dias sem. O número de crianças tratadas foi pequeno mas os resultados permitiram concluir que este regime de tratamento aparentemente não altera o peso e a altura das crianças tratadas. O resumo em inglês pode ser lido abaixo:

(Neuromuscular Disorders, 2012) Normal height and weight in a series of ambulant Duchenne muscular dystrophy patients using the 10 day on/10 day of prednisone regimen

K. ten Dam, I.J.M. de Groot, C. Noordam, N. van Alfen, J.C.M. Hendriks e L.T.L. Sie - The Netherlands

Prednisone treatment delays the progressive course of Duchenne muscular dystrophy. The aim of this study was to determine the  influence of the 10 day on/10 day of treatment on height and weight. We retrospectively reviewed the growth and weight charts of Duchenne patients born between 1988 and 2006 (patients between 4 and 9 years old, being able to walk in the home situation). Forty-seven patients were eligible for further analysis and divided into two groups: 33 patients treated with prednisone and 14 non-prednisone treated patients. Results of a median follow-up of 57 months (range 27–146) are described. By using linear mixed models this study demonstrates that height and body mass index in prednisone-treated patients with 10/10 regimen are not significantly diferent compared to untreated patients. We cautiously conclude that the alternating prednisone regimen has no apparent side effects on weight and height in the ambulatory phase of Duchenne muscular dystrophy.

USA -  nesta pesquisa realizada em vários centros no mundo, os autores estudaram a pentoxifilina, uma droga que demonstrou efeitos em camundongos. A droga foi usada por 12 meses em meninos com distrofia muscular de Duchenne tratados com corticóides. Os resultados observados não demonstraram efeito da droga sobre a força muscular e na função pulmonar. O resumo em inglês pode ser lido abaixo:

(Neurology, 2012) Pentoxifylline as a rescue treatment for DMD. A randomized double-blind clinical trial

D.M. Escolar, A. Zimmerman, T. Bertorini, P.R. Clemens, A.M. Connolly, L. Mesa, K. Gorni, A. Kornberg, H. Kolski, N. Kuntz, Y. Nevo, C. Tesi-Rocha, K. Nagaraju, S. Rayavarapu, L.P. Hache, J.E. Mayhew, J. Florence, F. Hu, A. Arrieta, E. Henricson, R.T. Leshner, and J.K. Mah

Abstract

Objective: To determine whether pentoxifylline (PTX) slows the decline of muscle strength and function in ambulatory boys with Duchenne muscular dystrophy (DMD).

Methods: This was a multicenter, randomized, double-blinded, controlled trial comparing 12 months of daily treatment with PTX or placebo in corticosteroid-treated boys with DMD using a slow-release PTX formulation (∼20 mg/kg/day). The primary outcome was the change in mean total quantitative muscle testing (QMT) score. Secondary outcomes included changes in QMT subscales, manual muscle strength, pulmonary function, and timed function tests. Outcomes were compared using Student t tests and a linear mixed-effects model. Adverse events (AEs) were compared using the Fisher exact test

Results: A total of 64 boys with DMD with a mean age of 9.9 ± 2.9 years were randomly assigned to PTX or placebo in 11 participating Cooperative International Neuromuscular Research Group centers. There was no significant difference between PTX and the placebo group in total QMT scores (p = 0.14) or in most of the secondary outcomes after a 12-month treatment. The use of PTX was associated with mild to moderate gastrointestinal or hematologic AEs

Conclusion: The addition of PTX to corticosteroid-treated boys with DMD at a moderate to late ambulatory stage of disease did not improve or halt the deterioration of muscle strength and function over a 12-month study period.

Classification of evidence: This study provides Class I evidence that treatment with PTX does not prevent deterioration in muscle function or strength in corticosteroid-treated boys with DMD

 

USA -  selecionei 29 pesquisas que serão apresentadas no maior congresso mundial de neurologia. As pesquisas que estão mais avançadas são a da terapia com ACE-031 com resultados preliminares bons em Duchenne (pesquisa 1) e a que demonstra a melhora da função cardíaca em pacientes com Duchenne tratados com drogas cardioprotetoras como os inibidores da ECA e os beta bloqueadores (pesquisa 5)

Suécia - pacientes com distrofia muscular de Duchenne e Becker podem apresentar osteoporose, mesmo sem o uso de corticóides. Neste estudo de seguimento da densitometria óssea por 4 anos os pesquisadores encontraram densidade óssea maior nos pacientes com Becker e uma progressiva redução nos pacientes com Duchenne, demonstrando uma correlação entre força muscular e osteoporese e a necessidade de prolongar a deambulação em pacientes com Duchenne.  O resumo em inglês pode ser lido abaixo:

(Acta Paediatrica, 2012, 101(4): 424-32) Bone mass development in patients with Duchenne and Becker muscular dystrophies: a 4-year clinical follow-up

Ann-Charlott Söderpalm (ann-charlott.soderpalm@vgregion.se), Per Magnusson,, Anne-Christine Åhlander, Jón Karlsson, Anna-Karin Kroksmark,Már Tulinius, Diana Swolin-Eide  - Sweden

Aim: To investigate the longitudinal development of bone mass in patients with Duchenne and Becker muscular dystrophies and to study the impact of muscle strength and motor function on bone mass in these patients.                                                             Methods: Eighteen patients with Duchenne muscular dystrophy (2.3–19.7 years at baseline) and six patients with the milder Becker muscular dystrophy (10.8–18.9 years at baseline) were followed during a 4-year period with respect to areal bone mineral density (BMD), motor function and muscle strength.
Results: Greater bone mineral accretion was observed in the Becker patient group compared with the age-related Duchenne group above 10 years of age, and the older patients with Duchenne experienced decreased femoral neck BMD during the study period. In the study group, significant correlations were found between BMD in the lower extremities and muscle function parameters.
Conclusions: The differences in BMD between patients with Duchenne and Becker as well as between different bone measurement sites demonstrated in the present study point out the importance of preserving muscle strength and motor function in patients with muscular dystrophy. Moreover; it highlights the value of performing region-specific analysis of the bone quality in these patients.

USA - laminina 111 está presente na fase embrionária e não é encontrada na musculatura adulta. Neste experimento a laminina 11 foi administrada a camundongos com distrofia muscular congênita. Os animais tratados por via sistêmica com laminina 111 apresentaram aumento da força muscular e redução das alterações patológicas.

China -  células mesenquimais obtidas da medula óssea de camundongos foram submetidas a terapia gênica com vírus contendo microgene da distrofina. Após o tratamento elas forma inoculdas em camundongos e após 12 semanas observou-se melhora das alterações musculares, mantendo a capacidade de regeneração prolongadamente. O resumo em inglês pode ser lido abaixo:

(Biochemical and Biophysical Research Communications, 2012) Restoration of Muscle Fibers and Satellite Cells after Isogenic MSC Transplantation with Microdystrophin Gene Delivery

Shan-wei Feng, , Fei chen, , Jiqing Cao,  Ying-yin Liang, Xin-ming Song, Cheng Zhang  - China

 Duchenne muscular dystrophy is the most prevalent inheritable  muscle disease. Transplantation of autologous stem cells with gene direction is an ideal therapeutic approach for the disease. The current  study aimed to investigate the restoration of myofibers in mdx mice after mdx bone marrow-derived mesenchymal stem cell (mMSC)  transplantation with human microdystrophin delivery. Possible mechanisms of action were also studied. In our research, mMSCs were successfully transduced by retrovirus carrying a functional human microdystrophin gene. Transplantation of transduced mMSCs enabled persistent dystrophin restoration in the skeletal muscle of mdx mice up to the 12th week after transplantation. Simultaneous coexpression of human microdystrophin and desmin showed that implanted mMSCs are capable of long-term survival as muscle satellite cells.

 

Brasil -  trata-se de mais um aviso para os pais de crianças com distrofia muscular de Duchenne que ainda deambulam e podem ser beneficiar do salto do exon 51, participando desta pequisa. Se a criança ainda consegue caminhar e não tem o diagnóstico genético ela deve ser submetida ao exame do DNA para identificação da mutação. As mutações que se beneficiam do tratamento podem ser vista aqui.

Itália -  Nesta pesquisa os pacientes, 71 no total, foram tratados com um anti-inflamatório (ibuprofen) e com um doador de óxido nítrico (dinitrato de isosorbitol), medicamento usado para tratamento da angina do peito. Os pacientes tinham distrofia de Duchenne, Becker e cinturas) e foram tratados por um ano. Os medicamentos foram bem tolerados com poucos efeitos colaterais com algum grau de melhora. O resumo em inglês pode ser lido abaixo:

 (Pharmacological Research, January 2012) Nitric oxide donor and non steroidal anti inflammatory drugs as a therapy for muscular dystrophies: evidence from a safety study with pilot efficacy measures in adult dystrophic patients

Maria Grazia D’Angelo, Sandra Gandossini, Filippo Martinelli Boneschi, Clara Sciorati, Sara Bonato, Erika Brighina, Giacomo Pietro Comi, Anna C. Turconi, Francesca Magri, Giuseppe Stefanoni, Silvia Brunelli, Nereo Bresolin, Dario Cattaneo, Emilio Clementi - Italy

This open-label, single centre pilot study was designed to evaluate safety and tolerability of the combination of the drugs isosorbide dinitrate, a nitric oxide donor, and ibuprofen, a non steroid anti-inflammatory drug, in a cohort of adult dystrophic patients (Duchenne, Becker and Limb-girdle muscular dystrophy). Seventy-one patients were recruited: 35, treated with the drug combination for 12 months, and 36 untreated. Safety and adverse events were assessed by reported signs and symptoms, physical examinations, blood tests, cardiac and respiratory function tests. Exploratory outcomes measure, such as the motor function measure scale, were also applied.

Good safety and tolerability profiles of the long-term co-administration of the drugs were demonstrated. Few and transient side effects (i.e. headache and low blood pressure) were reported. Additionally, exploratory outcomes measures were feasible in all the disease population studied and evidenced a trend towards amelioration that reached statistical significance in one dimension of the MFM scale. Systemic administration of ibuprofen and isosorbide dinitrate provides an adequate safety margin for clinical studies aimed at assessing efficacy.

 

Alemanha - os corticóides continuam sendo a melhor alternativa terapêutica da distrofia muscular de Duchenne, mas apresentam efeitos colaterais. Nesta pesquisa os autores construiram uma partícula de gordura contendo em seu interior o corticoides com objetivo de manter o efeito prolongado da droga e reduzindo seus efeitos colaterais. Os resultados demonstraram que o corticóide administrado como lipossoma não é superior ao tratamento convencional. O resumo em inglês pode ser lido abaixo:

(Journal of Neuroscience Research, 2012) Motor performance of young dystrophic mdx mice treated with long-circulating prednisolone liposomes

Charlotte Weller, Jana Zschüntzsch, Gregor Makosch, Josbert M. Metselaar, Florian Klinker, Lars Klinge, David Liebetanz and Jens Schmidt - Germany

For Duchenne muscular dystrophy (DMD), a common myopathy that leads to severe disability, no causal therapy is available. Glucocorticosteroids improve patients' muscle strength, but their long-term use is limited by negative side effects. Thus, pharmacological modifications of glucocorticosteroids are required to increase the efficacy by drug targeting. Liposomal encapsulation augments systemic half-life and local tissue concentrations of glucocorticosteroids and, at the same time, reduces systemic side effects. In this study, the efficacy of novel, long-circulating, polyethylene-glycol-coated liposomes encapsulating prednisolone was compared with free prednisolone in the treatment of mdx mice, a well-established animal model for DMD. Using an objective and sensitive computerized 24-hr detection system of voluntary wheel-running in single cages, we demonstrate a significant impairment of the running performance in mdx compared with black/10 control mice aged 3–6 weeks. Treatment with liposomal or free prednisolone did not improve running performance compared with saline control or empty liposomes. Histopathological parameters, including the rate of internalized nuclei and fiber size variation, and mRNA and protein expression levels of transforming growth factor (TGF)-β and monocytes chemotactic protein (MCP)-1 also remained unchanged. Bioactivity in skeletal muscle of liposomal and free prednisolone was demonstrated by elevated mRNA expression of muscle ring finger protein 1 (MuRF1), a mediator of muscle atrophy, and its forkhead box transcription factors (Foxo1/3). Our data support the assessment of voluntary running to be a robust and reproducible outcome measure of skeletal muscle performance during the early disease course of mdx mice and suggest that liposomal encapsulation is not superior in treatment efficacy compared with conventional prednisolone. Our study helps to improve the future design of experimental treatment in animal models of neuromuscular diseases

 

Alemanha - vetores virais contendo um microgene da distrofina  foram injetados por via venosa em camundongos com distrofia muscular. Após 10 meses de tratamento os animais apresentavam melhora ecocardiográfica e histológica demonstrando as possibilidades futuras deste tratamento.

França - trata-se de um estudo preliminar para determinar a segurança e a dose necessária para tratamento da distrofia muscular tipo cinturas 2C. Os pacientes receberam um injeção intramuscular contento um vetor viral que levava o gene da gama sarcoglican.  O seguimento foi de 6 meses e não houve efeitos colaterais graves. Os melhore resultados obtidos foram em pacientes que receberam as doses mais altas de vetores virais. Novos estudos deveram ser feitos para observar resultados da administração do tratamento por via venosa para todos os músculos.

Austrália - a N-acetilcisteína é uma droga fluidificante de secreções e que tem ação anti-oxidante. Estudos prévios em camundongos com distrofia muscular já demostram efeito benéfico. Nesta pesquisa a droga demonstrou um efeito benéfico em proteger o músculo diafragma da necrose promovida pelo exercício.

USA - a droga halofuginose mostrou benefícios no tratamento de camundongos com distrofia muscular; a droga pertence a um laboratório de biotecnologia que não tinha interesse em progredir com as pesquisas da droga. Duas famílias americanas decidiram comprar a droga por um milhão de dólares e vão investir nas pesquisas com esta droga em pacientes com distrofia muscular de Duchenne.

Brasil - o stress oxidativo contribui para o agravamento das lesões musculares da distrofia. Neste experimento camundongos jovens foram tratados com ácido ascorbico (vitamina C) e os resultados foram comparados com animais que receberam solução salina. Os animais tratados apresentaram redução dos níveis de CK, redução da necrose muscular e das citocinas relacionadas com stress oxidativo e inflamação. Os autores concluem que a vitamina C tem um efeito protetor nos camundongos com distrofia muscular.

Dinamarca - estudo retrospectivo realizado em um hospital da Dinamarca, acompanhando 1658 pacientes com distrofia miotônica no período de 1977 a 2008 constatou aumento do risco de câncer primariamente no cérebro, ovário, intestino grosso e endométrio. Esta informação é relevante para se executar estratégias de prevenção nas pessoas com esta forma de distrofia.

USA - no aguardo de um tratamento definitivo para a distrofia muscular de Duchenne, o uso de corticóides é a única arma terapêutica utilizada. Muitas estratégias tem sido testadas e algumas de fácil uso e seguras. Este artigo de revisão aborda a possibilidade de tratamento da doença com suplementos nutricionais. A enfase no artigo é para o chá verde e para aminoácido de cadeia ramificada leucina. Ambos são adequados para consumo humano, são facilmente tolerados e sem efeitos colaterais e, com os dados experimentais já existentes poderiam ser testados em seres humanos. Os estudos experimentais mostram aumento global da resistência e aumento da função muscular.

Inglaterra - nesta investigação entre 37 a 42% dos atendimentos a portadores de doenças neuromusculares em serviços de emergência poderiam ser evitados. O número de especialistas nestas doenças é pequeno, incluindo médicos, fisioterapeutas, etc. No Brasil, onde não temos estatísticas confiáveis e o número de especialistas é muito pequeno o problema deve ser ainda maior.

USA - nesta pesquisa inicial os pacientes receberam no braço uma injeção intramuscular com o vetor viral carregando o gene da distrofina; no outro braço eles receberam uma injeção salina. O estudo não tinha objetivo de tratar mas sim observar as reações, efeitos colaterais, dose e segurança do tratamento. O resumo em inglês do tratamento pode ser lido abaixo:

(Molecular Therapy, 2011) Phase 1 Gene Therapy for Duchenne Muscular Dystrophy Using a Translational Optimized AAV Vector

Dawn E Bowles, Scott WJ McPhee, Chengwen Li, Steven J Gray, Jade J Samulski, Angelique S Camp, Juan Li, Bing Wang, Paul E Monahan, Joseph E Rabinowitz, Joshua C Grieger, Lakshmanan Govindasamy, Mavis Agbandje-McKenna, Xiao Xiao and R Jude Samulski - USA

Efficient and widespread gene transfer is required for successful treatment of Duchenne muscular dystrophy (DMD). Here, we performed the first clinical trial using a chimeric adeno-associated virus (AAV) capsid variant (designated AAV2.5) derived from a rational design strategy. AAV2.5 was generated from the AAV2 capsid with five mutations from AAV1. The novel chimeric vector combines the improved muscle transduction capacity of AAV1 with reduced antigenic crossreactivity against both parental serotypes, while keeping the AAV2 receptor binding. In a randomized double-blind placebo-controlled phase I clinical study in DMD boys, AAV2.5 vector was injected into the bicep muscle in one arm, with saline control in the contralateral arm. A subset of patients received AAV empty capsid instead of saline in an effort to distinguish an immune response to vector versus minidystrophin transgene. Recombinant AAV genomes were detected in all patients with up to 2.56 vector copies per diploid genome. There was no cellular immune response to AAV2.5 capsid. This trial established that rationally designed AAV2.5 vector was safe and well tolerated, lays the foundation of customizing AAV vectors that best suit the clinical objective (e.g., limb infusion gene delivery) and should usher in the next generation of viral delivery systems for human gene transfer.

 

 

USA e Chile:  os pesquisadores estudaram o stress oxidativo e as alterações do cálcio intracelular na cardiomiopatia de camundongos com distrofia muscular. O uso de apocinina, um inibidor da NOX 2 causou menor stress oxidativo, regulou os níveis de cálcio intracelular cardíaco e causou alterações eletrofisiológicas que melhoraram a contração cardíaca e  reduziram a formação de arritmias. A pesquisa está sendo apresentada no Congresso da Sociedade Americana de Cardiologia  e o resumo em inglês pode ser lido abaixo:

(American Heart Association Meeting, Orlando 2011) NOX2 Inhibition Restores Contractility, Intracellular Calcium Handling and Reduces Arrhythmogenicity in Dystrophic Cardiomyopathy

Daniel R Gonzalez1; Adriana V Treuer1; Raul A Dulce2; Guillaume Lamirault2; Joshua M Hare2

1 Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile
2 Interdisciplinary Stem Cell Institute, Univ of Miami, Miami, FL

Background. Dystrophic cardiomyopathy is the cardiac manifestation of three closely related diseases that include Duchenne and Becker muscular dystrophies, and X-linked dilated cardiomyopathy. Oxidative stress is characteristic of cardiomyopathies. Intracellular calcium ([Ca2+]i) handling is abnormal in the heart of the mdx mouse, a model of Duchenne muscular dystrophy. We tested the hypothesis that oxidative stress may be responsible of disturbances in Ca2+ handling and contractility in this model.

Methods and results. We used mdx mice with established cardiomyopathy: ejection fraction of 56.7 ± 0.5 % in mdx vs. 70.8 ± 2.4% in wild type. We found increased expression (fivefold) of the NADPH oxidase NOX2 in the mdx hearts compared to wild type, along with increased superoxide production, measured as intensity of dihydroethidium staining (p<0.05 vs. wild type). Treatment with apocyinin (30 min, 100 µmol/L), a NOX2 inhibitor, decreased superoxide in mdx (p<0.05 vs. untreated). Next, we studied the impact of NOX2 inhibition on contractility and calcium handling in isolated cardiomyocytes. Contractility, assessed as sarcomere shortening, was decreased in mdx myocytes compared to wild type (p<0.05). Pre-treatment with apocynin restored this response to normal levels. In addition, the amplitude of evoked [Ca2+]i transients (measured as fura-2 fluorescence) that was diminished in mdx myocytes (p<0.05), was also restored upon NOX2 inhibition. Total sarcoplasmic reticulum (SR) Ca2+ content (evaluated as caffeine-induced Ca2+ release) was reduced in mdx hearts (p<0.05). This content was normalized by apocynin treatment. At the same time, NOX2 inhibition decreased dramatically the production of spontaneous diastolic calcium release events in mdx myocytes (p<0.05, ANOVA).

Conclusions. These results indicate that in mdx hearts, NOX2 inhibition reduces oxidative stress, improving the SR [Ca2+] handling and contractility. Additionally, NOX2 inhibition reduced the sensitivity of the ryanodine receptor, reducing the incidence of diastolic Ca2+ waves. Targeting of NOX2 in may be therapeutically helpful to increase cardiac performance and avoid the incidence of ventricular arrhythmias in Duchenne and other dystrophic cardiomyopathies.

Japão - resveratrol é um potente antioxidante extraído da casca da uva. O tratamento prolongado com altas doses de resveratrol em  camundongos com distrofia muscular melhorou a função cardíaca e reduziu o grau de fibrose. A pesquisa está sendo apresentada no Congresso da Sociedade Americana de Cardiologia  e o resumo em inglês pode ser lido abaixo:

(American Heart Association Meeting, Orlando 2011) Long-Term Treatment with the SIRT1 Activator Resveratrol Ameliorates Cardiomyopathy in Dystrophin-Deficient Mice

Atsushi Kuno1; Yusuke Hori2; Masaya Tanno1; Hidemichi Kouzu1; Takahito Itoh1; Daisuke Sunaga1; Yoshiyuki Horio2; Tetsuji Miura1

1 Second Dept of Internal Medicine, Sapporo Med Univ Sch of Medicine, Sapporo, Japan
2 Dept of Pharmacology, Sapporo Med Univ Sch of Medicine, Sapporo, Japan

Background: Loss of cardiac dystrophin eventually leads to cardiac dysfunction and heart failure, which is a main cause of death in patients with Duchenne muscular dystrophy (DMD). However, there is still no effective pharmacological therapy. Here, we examined the effect of resveratrol, an activator of the longevity factor SIRT1, on cardiomyopathy in dystrophin-deficient mice (mdx), a model of DMD.

Methods and Results:Mdx were left untreated or received resveratrol (400 mg/kg/day orally) for 32 weeks starting at 9 weeks of age. Age-matched C57BL10 served as controls. Mice were examined by echocardiography at 40 weeks of age and sacrificed. Compared with C57BL10, mdx showed significant cardiac hypertrophy as evidenced by higher heart-to-body weight (HW/BW) ratio (4.1±0.6 vs. 5.4±0.8 mg/g), increased diastolic ventricular thickness (0.72±0.02 vs. 0.82±0.03 mm), larger cardiomyocyte cross-sectional area (1.7 fold), and induction of atrial natriuretic peptide mRNA expression (4.3 fold). Resveratrol treatment significantly attenuated cardiac hypertrophy (HW/BW: 4.2±0.1) in mdx. Left ventricular (LV) dimension and LV ejection fraction were similar among the three study groups, but diastolic posterior wall movement, an index of LV diastolic function, was improved by resveratrol in mdx (20.8±0.7 vs. 26.2±1.3 mm/sec, p<0.05). Tissue area stained for fibronectin and tissue level of collagen mRNA, two indices of fibrosis, in mdx were reduced to 48% and 57% of untreated controls, respectively, by resveratrol. Myocardial mRNA level of the fibrogenic cytokine TGFβ1, extent of phosphorylation of extracellular signal-regulated kinase 1/2, mediators of cardiac hypertrophy and fibrosis, in mdx hearts were not reduced by resveratrol. However, resveratrol suppressed the upregulation of protein level of the transcription co-activator p300, a pro-hypertrophic and -fibrotic protein acetylase, in the mdx myocardium. In C2C12 myoblasts, resveratrol decreased p300 protein, and this effect was blocked by SIRT1 knockdown.

Conclusion: Resveratrol attenuates ventricular fibrosis and improves diastolic LV function in mdx presumably by p300 downregulation via SIRT1 activation. SIRT1 activation may be a novel strategy in treatment of cardiomyopathy in DMD.

Japão - este grupo de pesquisadores  tem uma longa lista de pesquisas utilizando  antibióticos aminoglicosídeos na mutação de ponto da distrofia muscular de Duchenne. Na pesquisa atual eles tem resultados animadores com um novo aminoglicosídeo semi-sintético a arbekacina. O resumo em inglês que será apresentado em dezembro pode ser lido abaixo:

 (ASCB 2011, Denver - Colorado) Arbekacin as a therapeutic readthrough inducer for treatment of nonsense mutation-mediated Duchenne muscular dystrophy

M. Shiozuka, A. Nishida, M. Matsuo, M. Yoshida, Y. Nonomura, R. Matsuda - Japan

 Translational readthrough of a premature termination codon is a promising therapeutic method in more than 2,400 distinctly inherited human diseases.  We previously reported that negamycin, a dipeptide antibiotic, that binds to the ribosomal decoding site and alters translational accuracy, successfully restored dystrophin expression with less toxicity than gentamicin in mdx mouse, which carries a premature termination codon in the dystrophin gene.  In order to measure translational readthrough activity with  quantitative accuracy, we established a  novel transgenic mouse strain, named READ (Readthrough Evaluation and Assessment by Dual reporter).  We found that arbekacin induced the in vivo nonsense suppression in READ mice dose-dependently, and promotes the accumulation of  ystrophin, reduction of serum creatine kinase activity and improvement of contractile function in  mdx mice.  Moreover, arbekacin exhibits restoration of dystrophin expression on muscle cell obtained by biopsies from Duchenne muscular dystrophy patients caused by nonsense mutations.  We have validated the efficacy of arbekacin on dystrophin-deficient muscle that we ultimately wish to treat.  Arbekacin is a brekthrough readthrough-inducing drug for muscular dystrophy patients harboring nonsense mutations.  This work was supported in part by The Ichiro Kanehara Foundation (to MS), Fugaku Foundation (to MS), Health and Labour Sciences Research Grant for Research on Psychiatric and Neurological Diseases and Mental Health (19A-020; to RM), Comprehensive Research on Disability Health and Welfare (H22-ShinkeiKin-Ippan-016; to RM), Nervous and Mental Disorders (20B-13; to RM) from the Ministry of Health, Labour and Welfare, Japan.  

Canada, Japão, USA - oligonucleotideos para salto de exon tem sido testado inclusive em pacientes com distrofia muscular de Duchenne; normalmente este tratamento é específico para um determinado exon. Nesta pesquisa em cães os autores descrevem um cocktail de oligonucleotídeos capaz de saltar vários exons que poderia beneficiar uma quantidade maior de pacientes. O resultado observado em cães foi promissor com expressão da distrofina e melhora das alterações histológicas dos músculos. O resumo em inglês que será apresentado em dezembro pode ser lido abaixo:

(ASCB 2011, Denver - Colorado) Therapeutic Multiple Exon-skipping Using Cell-penetrating Morpholinos for Dystrophic Dogs

T. Yokota, T. Nagata, A. Nakamura, N. Urasawa, T. Saito, R. Kole, P. Sazani, T. Partridge, E. Hoffman, S. Takeda – Canada, Japan, USA

 Duchenne muscular dystrophy (DMD),  the most common and fatal X-linked myopathy, and its milder form, Becker muscular dystrophy (BMD), are caused by mutations in  the dystrophin (DMD) gene. Antisense-mediated exon skipping therapy is currently one of the most promising molecular therapies for DMD. The exon skipping leads to the production of internally deleted in-frame mRNA transcripts but the truncated quasi-dystrophin retains some functions like BMD. Previously we demonstrated the first successful exon-skipping treatment in body-wide skeletal muscles in Canine X-linked muscular dystrophy (CXMD) using a cocktail of phosphorodiamidate morpholino oligomers (PMOs, morpholinos) targeting exon 6 and exon 8 of dystrophin mRNA. However, unmodified (bare) morpholino injections led to inefficient delivery to the heart, and dystrophin induction was barely detectable in the cardiac muscle. Here, we sought to recover the dystrophin expression in cardiac muscles in dystrophic dogs using morpholinos conjugated with negatively charged arginine-rich cell-penetrating peptides (PPMOs). We demonstrated that the delivery moieties significantly improved dystrophin production in both skeletal and cardiac muscles. Intravenous injections with PPMOs restored dystrophin expression in cardiac muscles accompanied by ameliorated histology. No obvious toxicity was detected by blood tests and histology. Our results show the potential of PMO conjugates as therapeutic agents for DMD.

USA - Ataluren tem sido testada para tratamento da mutação de ponto (mutação sem sentido) na distrofia muscular de Duchenne. Os resultados dos estudos experimentais já foram apresentados mas neste resumos novas análises são feita sobre os efeitos a droga. Os pacientes tratados com doses mais baixas tiveram melhor resultado no teste da caminhada de 6 minutos mas também apresentaram menor quantidade de quedas acidentais. O resumo em inglês pode ser lido abaixo:

(Annals of Neurology Vol 70 (suppl 15) 2011) Improvements in muscle function and accidental falling in Ataluren-treated patients with nonsense mutation dystrophinopathy (Duchenne/Becker Muscular Dystrophy - nmDBMD)

Russman BS (Portland, OR), Mathews KD (Iowa City, IA),Sampson JB (Salt Lake City, UT), Renfroe JB (Gulf Breeze,FL), Morsy MA, Elfring GL, Barth JA, Peltz SW(South Plainfield, NJ)

Objective: Dystrophinopathy patients progressively lose muscle function and become susceptible to accidental falling, the most common cause of limb fractures in this population. Ataluren is an investigational drug designed to overcome the effects of nonsense mutations, which are responsible for 13% of dystrophinopathy cases. In a pivotal trial in nmDBMD, low-dose ataluren demonstrated a clinically meaningful difference (29.7m) in change in 6-minute walk distance (6MWD) versus placebo (p=0.0584; post-hoc analysis). Secondary endpoints included timed function tests and patient/parentreported accidental falling. Methods: Males 5 yr of age with nmDBMD were stratified by age, corticosteroid use, and baseline 6MWD;randomized 1:1:1 to placebo; low-dose ataluren (10,10,20 mg/kg); or high-dose ataluren (20,20,40 mg/kg) orally TID; and evaluated every 6 wks for 48 wks. Results: The study enrolled 174 subjects (median [range] age=8 [5–20] yr, corticosteroid use=123/174 [71%], median [range] baseline 6MWD=360 [75–554] m). Differences in mean changes from baseline to Week 48 for low dose versus placebo were -2.40s stair ascend, -1.62s stair descend, -1.35s 10-m walk/run, and -0.01s stand from supine. Over 48 weeks, accidental falling declined in the low-dose arm versus placebo (relative ratio=0.37; post-hoc analysis). High dose-treated subjects with approximate peak plasma concentrations similar to low dose-treated subjects generally had outcomes similar to low dose-treated subjects. Conclusions: Subjects treated with ataluren 10,10,20 mg/kg experienced trends toward improvements in timed function tests and had fewer accidental falls versus placebo. These findings support the primary endpoint (6MWD) results showing a positive treatment effect for low-dose ataluren in this population.

Brasil -  cães com distrofia muscular receberam células tronco da gordura por via venosa e diretamente nos músculos, sem receber drogas imunossupressoras. O procedimento foi seguro e os músculos apresentaram expressão da distrofina por mais de seis meses após o tratamento. Não há informações sobre os resultados clínicos do tratamento sobre a força muscular dos animais.

Japão - em trabalho semelhante ao apresentado há uma semana (abaixo) pesquisadores utilizaram células mesenquimais e injetaram por via intramuscular em cães com distrofia muscular. Os resultados demonstraram que as células se diferenciaram ao longo prazo em músculos, tornando-se também uma alternativa de tratamento.

França - células tronco musculares foram cultivadas em laboratório e injetadas por via sistêmica em cães com distrofia muscular. O tratamento foi eficiente com expressão da distrofina, melhora das alterações patológicas, regeneração das células satélites;  estes efeitos persistiram por longo prazo. O resumo em inglês da pesquisa pode ser lido abaixo:

(The American Journal of Pathology, Available online 13 September 2011) Systemic Delivery of Allogenic Muscle Stem (MuStem) Cells Induces Long-Term Muscle Repair and Clinical Efficacy in Duchenne Muscular Dystrophy Dogs  

Karl Rouger, Thibaut Larcher, Laurence Dubreil, Jack-Yves Deschamps, Caroline Le Guiner, Gregory Jouvion, Bruno Delorme, Blandine Lieubeau, Marine Carlus, Benoît Fornasari, Marine Theret, Priscilla Orlando, Mireille Ledevin, Céline Zuber, Isabelle Leroux, Stéphane Deleau, Lydie Guigand, Isabelle Testault, Elisabeth Le Rumeur, Marc Fiszman, et al.   - France

Here, we characterized canine delayed adherent stem cells and investigated the efficacy of their systemic delivery in the clinically relevant DMD animal model to assess potential therapeutic application in humans. Delayed adherent stem cells, named MuStem cells (muscle stem cells), were isolated from healthy dog muscle using a preplating technique. In vitro, MuStem cells displayed a large expansion capacity, an ability to proliferate in suspension, and a multilineage differentiation potential. Phenotypically, they corresponded to early myogenic progenitors and uncommitted cells. When injected in immunosuppressed dystrophic dogs, they contributed to myofiber regeneration, satellite cell replenishment, and dystrophin expression. Importantly, their systemic delivery resulted  in long-term dystrophin expression, muscle damage course limitation with an increased regeneration activity and an interstitial expansion restriction, and persisting stabilization of the dog’s clinical status. These results demonstrate that MuStem cells provide an attractive therapeutic avenue for DMD patients.

 

Portugal - neste importante congresso serão apresentados mais de 370 trabalhos, sendo que eu copiei todos eles. Muitos não tem relação com a distrofia muscular, muitos tem qualidade muito ruim, muito são repetitivos ou já foram exaustivamente apresentados, mas é possível ter uma idéia dos caminhos para os quais as pesquisas são direcionadas.

São Paulo - pais, amigos e portadores de distrofia muscular estão convidados a participar de concentração organizada pelo grupo de pais de São Paulo, que ocorrerá no dia 17 de setembro de 2011 no vão livre do Masp, na Avenida Paulista, das 9:00hs as 12:00hs. Compareçam!

USA - nesta revisão são abordados as dificuldades para a terapia genética da distrofia muscular de Duchenne e as pesquisas que estão sendo feitas para retardar a evolução da doença. As dificuldades são muitas, as vezes parecem instransponíveis acarretando tensões entre pais, agências reguladoras e empresas farmacêuticas. Fica claro mais uma vez que a pressa dos pacientes não é a mesma dos pesquisadores. O resumo em inglês e o powerpoint das imagens pode ser visto abaixo:

(Current Opinion in Neurology 2011, 24:415–422) Impending therapies for Duchenne muscular dystrophy

Terence A. Partridge - USA

Purpose of review:  As the first genetic disease for which the culpable gene was identified by positional cloning, Duchenne muscular dystrophy has served as a paradigm for therapeutic approaches to neuromuscular disease, in which role it has proved especially testing. The large mass and broad distribution of the target tissue, skeletal muscle, have stretched the patience and ingenuity of those seeking therapeutic delivery of the largest known gene. The most promising recent advances are summarized in this article. Recent findings: The main obstacle to genetic therapies has been the development of vectors able to efficiently deliver large, potentially therapeutic, genetic constructs to the large and widely dispersed mass of body musculature. Recombinant viral vectors that efficiently transduce muscle are unable to carry the full-length construct. Myogenic cells that are able both to carry full-length genes and to repair muscles are technically challenging to produce in sufficient quantity. A recent promising approach is the use of agents that obviate the mutation. Summary: Although genetic and cell-mediated approaches are currently showing genuine promise in preclinical and clinical trials, there remains considerable interest in the development of agents that ameliorate the downstream pathology. One general challenge is the three- way tension between the interests of patients, regulators, and the biotechnology industry.

Impending_therapies_DMD 

USA - neste artigo o Dr. Bach presta uma homenagem ao seu mais antigo paciente com distrofia muscular de Duchenne em tratamento prolongado com ventilação não-invasiva (o paciente faleceu aos 48 anos de idade) Além dos seus próprios cuidados ele foi colaborador no treinamento de médicos do mundo todo, além de colaborar também em um livro; além disso Jeff tinha um blog em que divulgava a importância da assistência ventilatória na distrofia muscular. Neste artigo há uma crítica ao atendimento dos pacientes nos Estados Unidos já que em poucos centros estas informações são divulgadas ou colocadas em prática. É possível imaginar como também deve estar a assistência ventilatória no Brasil, mesmo como a portaria do Ministério da Saúde que oferece o Bipap aos portadores de doenças neuromusculares.

Itália - a genisteína isoflavona de soja tem sido usada na terapia de reposição hormonal em mulheres na menopausa. A droga é capaz de reduz mediadores de lesão muscular na distrofia muscular; camundongos foram tratados por 5 semanas e os resultados foram comparados com os efeitos do tratamento com corticóides. Houve redução das alterações morfológicas dos músculos, redução da CK, diminuição do stress oxidativo e melhora da força muscular. Os resultados foram semelhantes aos observados com o uso de corticóides em camundongos. 

Brasil - para que as pessoas possam saber quem poderá estar apto para a participar da pesquisa com oligonucleotídeos para tratamento da distrofia muscular de Duchenne  seguem algumas informações aqui.

Brasil - além do encontro de pais e cuidadores que se realizará no dia 27 de agosto de 2011 em Franca, serão realizados mais dois eventos em setembro: o Simpósio de Doenças Neuromusculares organizado pela OAPD no dia 15 de agosto de 2011 em São Paulo e a Jornada sobre distrofias musculares e doenças neurológicas organizada pela Acadim  no dia 16 de setembro de 2011 no Rio de Janeiro.

Itália - nesta pesquisa os autores utilizaram os mesangioblastos, células tronco dos vasos; as células foram adicionadas com cromossomo artificial contendo o gene da distrofina; em seguida as células foram novamente injetadas em camundongos imunossuprimidos. Estas células transplantadas se multiplicaram e se diferenciaram em músculos, e expressavam a distrofina. Houve melhora das alterações patológicas e da função muscular nestes camundongos. O artigo na íntegra pode ser lido aqui.

Suiça - trata-se do segundo grupo de pesquisa utilizando a melatonina em camundongos com distrofia muscular pelo seu efeito anti-oxidante; os animais tratados com a droga apresentaram aumento da força muscular, com redução dos radicais de oxigênio e redução da CK no sangue..

Reino Unido - 19 meninos com Duchenne foram tratados com oligonucleotídeos para salto do exon 51 por 12 semanas. Os objetivos e resultados foram os seguintes: Segurança e tolerabilidade - o tratamento demonstrou ser seguro e sem efeitos colaterais graves; Estudo da dose adequada - os melhores resultados foram observados na dose de 2mg/kg ou superior; Expressão da distrofina - aumento em valores significativos, e o maior aumento observado foi de 55%. Houve também aumento da expressão de outras proteínas musculares e redução de células inflamatórias nos músculos.

USA -  os autores descrevem o caso de um adolescente com distrofia muscular de Duchenne que iniciou o uso de corticóides diariamente aos 7 anos de idade e que também fez uso de órteses, além de ter sido submetido a cirurgia para correção de contraturas. Com este tratamento o rapaz consegue se manter em pé e consegue caminhar com apoio a pequenas distâncias. Os autores concluem que o tratamento com corticóides acompanahado de fisioterapia e o uso de órteses pode prolongar a deambulação e modificar a história natural da distrofia muscular de Duchenne. O resumo em inglês pode ser lido abaixo:

(Neuromuscular Disorders, 2011) Combination of steroids and ischial weight-bearing knee ankle foot orthoses in Duchenne’s muscular dystrophy prolongs ambulation past 20 years of age – A case report

Andrea C. Pardo, Twee Do, Ted Ryder, Amy Meyer, Lili Miles, Brenda L. Wong - USA

Patients with Duchenne muscular dystrophy (DMD) lose ambulation by age 12. Long-term steroids have lengthened ambulation by
2–5 years. Ischial weight-bearing knee ankle foot orthoses prolong ambulation for 2–3 years. We report the outcome of the ambulatory status of a patient with DMD treated with daily steroid therapy and orthoses. This male patient was diagnosed with DMD at age of 2. He has been treated with daily steroids since age 7 years. He lost the ability to arise from the floor and walk up steps at age 14 and lost ambulation by age 16. He was fitted with orthoses at age 16 following surgical correction of his lower extremity contractures and regained independent ambulation. At age 20, he was able to stand independently in his orthoses and take steps with moderate support. We conclude that a combination of daily steroids and orthoses prolongs ambulation beyond that of the natural history DMD

USA -  o lisinopril é uma droga usada no tratamento da hipertensão arterial e insuficiência cardíaca. A espironolactona é um diurético utilizado em insuficiência cardíaca. Os camundongos portadores de uma forma mais grave de distrofia foram tratados a partir dos 4 meses de idade em comparação com os tratados com 8 meses de idade e com os não tratados. Houve melhora das alterações patológicas e da função tanto cardíaca quanto dos músculos esqueléticos, com redução da fibrose. Como são drogas conhecidas e sabidamente úteis no tratamento da doença cardíaca, o seu uso precoce pode ser uma nova estratégia no tratamento da distrofia muscular de Duchenne. O resumo em inglês pode ser lido abaixo:

(Circulation, 2011) Early Treatment With Lisinopril and Spironolactone Preserves Cardiac and Skeletal Muscle in Duchenne Muscular Dystrophy Mice

Jill A. Rafael-Fortney, Neeraj S. Chimanji, Kevin E. Schill, Christopher D. Martin, Jason D. Murray, Ranjit Ganguly, Jenna E. Stangland, Tam Tran, Ying Xu, Benjamin D. Canan, Tessily A. Mays, Dawn A. Delfín, Paul M.L. Janssen, and Subha V. Raman - USA

Background—Nearly universal cardiomyopathy in Duchenne muscular dystrophy (DMD) contributes to heart failure and death. Because DMD patients show myocardial fibrosis well before functional impairment, we postulated that earlier treatment using drugs with antifibrotic effect may be beneficial.

Methods and Results—Three groups of 10 utrn+/−;mdx, or “het” mice, deficient for dystrophin and haploinsufficient for utrophin with skeletal myopathy and cardiomyopathy that closely mimics clinical DMD were studied. One het group received spironolactone and lisinopril starting at 8 weeks of life (het-treated-8); a second received the same starting at 4 weeks of life (het-treated-4), and the third het group was untreated. At 20 weeks, all mice had normal ejection fractions though circumferential strain rate was abnormal (−0.21±0.08) in untreated hets. This improved to −0.40±0.07 in het-treated-8 mice (P=0.003) and further improved to −0.56±0.10 in het-treated-4 mice (P=0.014 for het-treated-4 versus het-treated-8). Treated mice showed less cardiomyocyte damage, with a 44% reduction in intracardiomyocyte serum immunoglobulin G localization in het-treated-8 mice (P<0.0001) and a further 53% reduction in het-treated-4 mice (P=0.0003 versus het-treated-8); matrix metalloproteinases were similarly reduced. Cardiac, limb, and diaphragm function by ex vivo muscle testing remained at 80% of normal with early treatment compared to a decline to 40% of normal skeletal muscle function without treatment.

Conclusions—These findings offer clinically available medications with proven antifibrotic effect as a new therapeutic strategy in DMD. Early initiation greatly attenuated myocardial disease and, for the first time with these drugs, improved skeletal myopathy. Thus, early initiation of such agents warrants further clinical evaluation to maintain ambulatory, respiratory, and cardiac function for patients with DMD and related myopathies

 

USA - os corticóides são considerados o tratamento padrão para distrofia muscular de Duchenne. Há alguns esquemas diferentes de tratamento e este estudo tem o objetivo de comparar dois destes esquemas: dose diária (0,75mg/Kg/dia de prednisona) x dose alta em finais de semana (10mg/Kg/final de semana); 64 meninos com idade entre 4 e 10 anos foram estudados. A eficácia dos dois tratamentos foi equivalente e a quantidade de efeitos colaterais também. O estudo demonstra que o tratamento com dose diária e doses altas nos finais de semana são aceitáveis para uso em distrofia muscular de Duchenne. O resumo em inglês pode ser lido abaixo:

(Neurology, 2011) Randomized, blinded trial of weekend vs daily prednisone in Duchenne muscular dystrophy

D.M. Escolar, L.P. Hache, P.R. Clemens, A. Cnaan, C.M. McDonald, V. Viswanathan, A.J. Kornberg, T.E. Bertorini, Y. Nevo, T. Lotze, A. Pestronk, M.M. Ryan, E. Monasterio, J.W. Day, A. Zimmerman, A. Arrieta, E. Henricson, J. Mayhew, J. Florence, F. Hu, and A.M. Connolly - USA

Objective: To perform a double-blind, randomized study comparing efficacy and safety of daily and weekend prednisone in boys with Duchenne muscular dystrophy (DMD)

Methods: A total of 64 boys with DMD who were between 4 and 10 years of age were randomized at 1 of 12 centers of the Cooperative International Neuromuscular Research Group. Efficacy and safety of 2 prednisone schedules (daily 0.75 mg/kg/day and weekend 10 mg/kg/wk) were evaluated over 12 months

Results: Equivalence was met for weekend and daily dosing of prednisone for the primary outcomes of quantitative muscle testing (QMT) arm score and QMT leg score. Secondary strength scores for QMT elbow flexors also showed equivalence between the 2 treatment groups. Overall side effect profiles of height and weight, bone density, cataract formation, blood pressure, and behavior, analyzed at 12 months, did not differ between weekend and daily dosing of prednisone

Conclusions: Weekend dosing of prednisone is equally beneficial to the standard daily dosing of prednisone. Analysis of side effect profiles demonstrated overall tolerability of both dosing regimens

Classification of evidence: This study provides Class I evidence that weekend prednisone dosing is as safe and effective as daily prednisone in preserving muscle strength and preventing body mass index increases in boys with DMD over a 12-month period.

 

Franca - Fabrício Silva Rodrigues está organizando um encontro voltado para pais e cuidadores de pessoas com distrofia muscular de Duchenne. Com uma programação de palestras,  sessões de perguntas e respostas e debates, este encontro ocorrerá em 27 de agosto de 2011 em Franca, São Paulo.

Espanha - pesquisadores identificaram uma molécula natural, a abp1, que em camundongos com distrofia miotônica foi capaz de se ligar ao gene mutado e bloquear a formação da sequência de base que desencadeia a doença. A molécula precisará ainda por inúmeros testes em animais até que os estudos em humanos possa começar.

USA - o losartan tem sido estudado para tratamento da distrofia muscular com o objetivo de melhorar a força muscular e preservar o coração. Neste estudo em camundongos os autores utilizaram o losartan por tempo prolongado e observaram aumento da sobrevida e melhora da função cardíaca e redução da fibrose; no entanto não houve alteração significativa nos músculos esqueléticos, contrastando com estudos de outros autores.

Holanda e Reino Unido - 63 crianças com distrofia muscular de Duchenne em uso de corticoides foram acompanhadas por mais de 4 anos e algumas citocinas foram medidas periodicamente em comparação com crianças controle, sem distrofia muscular; os resultados mostraram que os inibidores teciduais da metaloproteinase tipo 1 e matrix metaloproteinase tipo 9 estavam significantemente aumentados em Duchenne em relação aos controles, enquanto que a  osteopontina não apresentou diferença; a matrix metaloproteinase tipo 9 também estava aumentada em crianças mais velhas, não deambulantes, quando comparado como os valores de crianças que ainda deambulavam; os inibidores teciduais da metaloproteinase tipo 1 não aumentaram com a idade; com isto os autores concluem que apesar do número de crianças estudadas ser pequeno, a matrix metaloproteinase tipo 9 pode ser um marcador da evolução da distrofia muscular de Duchenne.O resumo em inglês pode ser lido abaixo:

(Neuromuscular Disorders, 2011) Serum matrix metalloproteinase-9 (MMP-9) as a biomarker for monitoring disease progression in Duchenne muscular dystrophy (DMD)

V.D. Nadarajah, M. van Putten, A. Chaouch, P. Garrood, V. Straub, H. Lochmuller, H.B. Ginjaar, A.M. Aartsma-Rus,
G.J.B. van Ommen, J.T. den Dunnen, P.A.C. ’t Hoen - The Netherlands, United Kingdom

To identify serum biomarkers that allow monitoring of disease progression and treatment effects in Duchenne muscular dystrophy
(DMD) patients, levels of matrix metalloproteinase-9 (MMP-9), tissue inhibitors of metalloproteinase-1 (TIMP-1) and osteopontin
(OPN) were determined in 63 DMD patients on corticosteroid therapy. These proteins were selected for their role in the pathogenesis of muscular dystrophy. Levels of MMP-9 and TIMP-1 were significantly higher in sera of DMD patients compared to healthy controls, whereas the OPN levels showed no significant difference. MMP-9 levels were also observed to be significantly higher in older, nonambulant patients, compared to ambulant patients. Longitudinal data from a smaller cohort of DMD patients followed up for over 4 years showed that MMP-9, but not TIMP-1 increased significantly with age. Hence, MMP-9 is a potential DMD biomarker for disease progression. Future studies have to confirm whether serum MMP-9 levels can be used to monitor therapeutic response.

 

USA - os corticóides são utilizados como tratamento padrão da distrofia muscular de Duchenne e podem retardar a evolução da doença. Nesta pesquisa piloto a coenzima Q10, um potente antioxidante, foi utilizado em pacientes com idade entre 5 e 10 anos e utilizando corticóides. O estudo foi completado por 12  pacientes. Destes, nove apresentaram melhora da força muscular. Os pesquisadores concluiram que a conezima Q10 pode ter um efeito aditivo ao uso de corticóides e precisa ser estudada em grupos maiores de pacientes.

USA - com a melhora do tratamento, especialmente das complicações respiratórias tem aumentado a sobrevida da distrofia muscular de Duchenne e aumentado o número de portadores de cardiomiopatia. Nesta revisão o autor detalha os avanços no conhecimento da doença, os tratamentos disponíveis para a doença cardíaca e as perspectivas futuras. A sugestão é encaminhar esta revisão para o seu médico.

USA -  mulheres portadores da mutação do gene da distrofia muscular de Duchenne podem apresentar manifestações cardíacas da doença; 99 mulheres foram acompanhadas em média por 9 anos; 11 apresentaram cardiomiopatia, 9 apresentaram os sintomas ao longo deste acompanhamento; uma delas faleceu de doença cardíaca com 57 anos; este estudo demonstra a importância de realizar exames períodicos em portadoras de distrofia muscular de Duchenne/Becker. O resumo em inglês pode ser lido abaixo:

(Neurology, 2011) Cardiac abnormalities in a follow-up study on carriers of Duchenne and Becker muscular dystrophy

S.M. Schade van Westrum, E.M. Hoogerwaard, L. Dekker, T.S. Standaar, E. Bakker, P.F. Ippel, J.C. Oosterwijk, D.F. Majoor-Krakauer, A.J. van Essen, N.J. Leschot, A.A.M. Wilde, R.J. de Haan, M. de Visser, and A.J. van der Kooi - USA

Objectives: Cardiac involvement has been reported in carriers of dystrophin mutations giving rise to Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). The progress of these abnormalities during long-term follow-up is unknown. We describe the long-term follow-up of dilated cardiomyopathy (DCM) in DMD/BMD carriers.

Methods: A long-term follow-up study was performed among Dutch DMD/BMD carriers first analyzed in 1995. A cardiac history was taken, and all carriers were assigned a functional score to assess skeletal muscle involvement. Electrocardiography and M-mode and 2-D echocardiography were performed. DCM was defined as an enlarged left ventricle with a global left ventricle dysfunction or fractional shortening less than 28%. Slow vital capacity of the lung was measured by a hand-held spirometer.

Results: Ninety-nine carriers were monitored with a median follow-up of 9 years (range 7.0–10.6 years). Eleven carriers with DCM (10 DMD, 1 BMD) were identified. Nine of them developed DCM in the follow-up period. One of the patients with DCM reported in the 1995 study died of cardiac failure at age 57 years. DCM was more frequently found in carriers who were functionally symptomatic

Conclusion: Cardiac abnormalities in DMD/BMD carriers are progressive, as in patients with DMD/BMD

 

Itália - o enalapril é uma droga muito conhecida e utilizada no tratamento de doenças cardiovasculares; pertence a classe dos inibidores da ECA, que impede a síntese de angiotensina II, que parece ter uma ação pró-inflamatória e pró-oxidante.  Os resultados do  tratamento com enalapril dos camundongos com distrofia muscular foram comparados com os tratados com prednisona. Os animais tratados com enalapril apresentaram redução da atividade inflamatória e oxidante e redução da necrose dos músculos; houve também melhora da função muscular. Assim como o losartan, que já demonstrou efeito semelhante, o enalapril se candidata como tratamento complementar aos corticóides em pacientes com distrofia muscular de Duchenne. O resumo em inglês pode ser lido abaixo:

 (Pharmacological Research, 2011)  Enalapril treatment discloses an early role of angiotensin II in inflammation - and oxidative stress-related muscle damage in dystrophic mdx mice 

Anna Cozzoli, Beatrice Nico, Valeriana Teresa Sblendorio, Roberta Francesca Capogrosso, Maria Maddalena Dinardo, Vito Longo, Sara Gagliardi, Monica Montagnani, Annamaria De Luca - Italy

Inhibitors of angiotensin converting enzymes (ACE) are clinically used to control cardiomyopathy in patients of Duchenne muscular dystrophy. Various evidences suggest potential usefulness of long-term treatment with ACE inhibitors to reduce advanced fibrosis of dystrophic muscle in the mdx mouse model. However, angiotensin II is known to exert pro-inflammatory and pro-oxidative actions that might contribute to early events of dystrophic muscle degeneration. The present study has been aimed at evaluating the effects of an early treatment with enalapril on the pathology signs of exercised mdx mouse model. The effects of 1 and 5 mg/kg enalapril i.p. for 4-8 weeks have been compared with those of 1 mg/kg α-methyl-prednisolone (PDN), as positive control. Enalapril caused a dose-dependent increase in fore limb strength, the highest dose leading to a recovery score similar to that observed with PDN. A dose-dependent reduction of superoxide anion production was observed by dihydroethidium staining in tibialis anterior muscle of enalapril-treated mice, approaching the effect observed with PND. In parallel, a significant reduction of the activated form of the pro-inflammatory Nuclear Factor-kB has been observed in gastrocnemious muscle. Histologically, 5 mg/kg enalapril reduced the area of muscle necrosis in both gastrocnemious muscle and diaphragm, without significant effect on non-muscle area. In parallel no significant changes have been observed in both muscle TGF-β1 and myonuclei positive to phosphorylated Smad2/3. Myofiber functional indices were also monitored by microelectrodes recordings. A dose-dependent recovery of macroscopic chloride conductance has been observed upon enalapril treatment in EDL muscle, with minor effects being exerted in diaphragm. However a modest effect, if any, was found on mechanical threshold, a functional index of calcium homeostasis. No recovery was observed in creatine kinase and lactate dehydrogenase. Finally the results suggest the ability of enalapril to blunt angiotensin-II dependent activation of pro-inflammatory and pro-oxidant pathways which may be earlier events with respect to the pro-fibrotic ones, and may in part account for both functional impairment and muscle necrosis. The PDN-like profile may corroborate the combined use of the two classes of drugs in DMD patients so to potentiate the beneficial effects at skeletal muscle level, while reducing both spontaneous and PDN-aggravated cardiomyopathy.

Japão - camundongos com distrofia muscular foram tratados por 32 semanas com resveratrol, um conhecido anti-oxidante presente na casca da uva. Os autores observaram uma redução das alterações patológicas dos músculos com redução da fibrose e de radicais de oxigênio livre. O resumo, em inglês, pode ser lido abaixo:

(J. Pharmacol. Exp. Ther., Jun 2011) Resveratrol ameliorates muscular pathology in the dystrophic mdx mouse, a model for Duchenne muscular dystrophy

Yusuke S Hori, Atsushi Kuno, Ryusuke Hosoda, Masaya Tanno, Tetsuji Miura, Kazuaki Shimamoto, and Yoshiyuki Horio - Japan

Muscular dystrophies are inherited myogenic disorders accompanied by progressive skeletal muscle weakness and degeneration. We previously showed that resveratrol (3,5,4'-trihydroxy-trans-stilbene), an anti-oxidant and activator of the NAD+-dependent protein deacetylase SIRT1, delays the progression of heart failure and prolongs the lifespan of δ-sarcoglycan-deficient hamsters. Because a defect of dystrophin-associated protein complex causes muscular dystrophies, and δ-sarcoglycan is a component of this complex, we hypothesized that resveratrol might be a new therapeutic tool for muscular dystrophies. Here we examined resveratrol′s effect in mdx mice, an animal model of Duchenne muscular dystrophy. Mdx mice that received resveratrol in the diet for 32 weeks (4 g/kg diet) showed significantly less muscle-mass loss and non-muscle interstitial tissue in the biceps femoris compared with mdx mice fed a control diet. In the muscles of these mice, resveratrol significantly decreased oxidative damage shown by the immunostaining of nitrotyrosine and 8-hydroxy-2′-deoxyguanosine and suppressed the up-regulation of NADPH oxidase subunits Nox4, Duox1, and p47phox. Resveratrol also reduced the number of α-smooth muscle actin (α-SMA)+myofibroblast cells and endomysial fibrosis in the biceps femoris, although the infiltration of CD45+ inflammatory cells and increase in TGF-β1 were still observed. In C2C12 myoblast cells, resveratrol pretreatment suppressed the TGF-β1-induced increase in reactive oxygen species, fibronectin production, and expression of α-SMA, and SIRT1 knockdown blocked these inhibitory effects. SIRT1 siRNA also increased the expression of Nox4, p47phox, and α-SMA in C2C12 cells. Taken together, these findings indicate that SIRT1 activation may be a useful strategy for treating muscular dystrophies.
 

Índia -  a anemia Diamond-Blackfan é uma doença hereditária grave que pode ser tratada com o transplante de medula óssea; o paciente de 9 anos tratado com transplante de medula óssea apresentava também distrofia muscular de Duchenne. Após o tratamento os autores observaram células do doador em porcentagem de 8 a 10,4% nos músculos do paciente, demonstrando a viabilidade desta modalidade de tratamento na Distrofia Muscular de Duchenne, ainda que experimental.

USA - neste estudo retrospectivo foram estudados os pacientes com Duchenne, de 13 a 19 anos, que fazem tratamento com corticóides. A grande maioria dos pacientes não apresentava evidência de puberdade. Os resultados demonstram a necessidade de acompanhamento especializado na puberdade a partir dos 12 anos com intervenção após os 14 anos. O tratamento deve ser interdisciplinar e avaliar todas as doenças concomitantes como a osteoporose. O resumo em inglês pode ser lido abaixo:

(ENDO 2011, Boston, 6-9 June) Puberty Is Delayed or Absent in Duchenne Muscular Dystrophy Boys on Chronic Glucocorticoid Therapy

MM Rutter, SR Rose, J Collins, H Sucherew, B Wong. Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH; Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH; Cincinnati Children's Hospital Medical Center, Cincinnati, OH.

Background: Duchenne Muscular Dystrophy (DMD) is a progressive neuromuscular disorder affecting 1 in 3500 boys. Chronic glucocorticoid (GC) treatment is considered standard therapy, and slows disease progression. However, GCs cause osteoporosis, growth failure, obesity, insulin resistance and pubertal delay, compromising quality of life. Absent or delayed puberty is an important problem which negatively impacts bone health, growth, self esteem and muscle strength. The prevalence in DMD is not known, and it is frequently under-recognized and untreated.
Objective: To determine the prevalence of delayed or absent puberty in DMD on GC therapy.
Methods: Patients aged 13 to 19 years with confirmed DMD on chronic daily GC treated in the Cincinnati Neuromuscular Comprehensive Care Center were studied. Clinical data was obtained from an IRB-approved database and chart review. Pubertal status was assessed annually by measuring early morning total testosterone concentrations and/ or pubertal examination by an endocrinologist.
Results: Of 64 boys aged ≥ 13 years, 56 (88%) had no evidence of puberty. Of 49 boys aged ≥ 14 years, 41(84%) showed no signs of puberty. Overall, 3 boys had pubertal arrest with very low testosterone levels for age or testicular size. Only 5 boys were in puberty; of these, 2 had 4 mL testes at age 14 years and 2 showed no significant progression over 2 years. Of 22 boys aged ≥ 16 years, 21 (95%) still had absent or arrested puberty. 47/59 (80%) boys with absent/ arrested puberty had severe osteoporosis. Absent puberty was distressing to 25 boys who as a result were treated with testosterone, 14 using topical gel.
Conclusions: Most DMD boys on chronic daily GC do not develop spontaneous puberty, or fail to progress. The problem does not tend to improve with age. Primary providers need an increased awareness to facilitate timely referral to an endocrinologist. We recommend clinical assessment and discussion by age 12 and referral by age 14 years. Management should be proactive and interdisciplinary, with attention to related co-morbidities such as osteoporosis.

Itália - é a segunda pesquisa com a droga NCX320; a droga é uma modificação do antinflamatório ibuprofen que foi associado ao óxido nítrico, um potente vasodilatador. Nesta pesquisa a droga foi usada em camundongos que apresentam um modelo de distrofia semelhante a uma forma de distrofia tipo cinturas. Houve uma melhora das alterações patológicas e redução da enzima CK.

USA - a droga ripamicina é imunossupressora. O uso da droga em tratamento por 6 semanas de camundongos com distrofia muscular resultou em redução da necrose muscular.

Reino Unido - a droga SMT C1100 atua aumentando os níveis de utrofina, proteína que pode substituir as ações da distrofina. Dada por via oral, uma vez ao dia, aos camundongos com distrofia muscular houve significativa redução das alterações patológicas, melhora da força e melhor resistência a fadiga.  Os resultados foram descritos como excelentes.

USA - Poloxamer P188 tem sido testado há mais de 10 anos para tratamento da distrofia muscular. É uma droga que poderia proteger a membrana muscular como um "cimento", evitando a degeneração do músculo. Nesta pesquisa em camundongos fêmeas velhas a função cardíaca foi agravada com uma medicação (o isoproterenol). Os animais tratados apresetaram menor fibrose do músculo cardíaco.

Brasil - este texto traduzido para o português por Marcelo D.P. de Oliveira da ACADIM permite identificar quais as mutações do gene da distrofina podem ser tratadas com oligonucleotídeos

Brasil - os oligonucleotídeos para salto do exon 51 tem sido estudados em vários países por duas empresas. Está em planejamento um estudo clínico com oligonucleotídeos para ser realizado no Brasil. Há mutações específicas que podem se beneficiar deste tratamento. Ainda em inglês existe este texto que ajuda a identificar quais as mutações podem ser tratadas por oligonulceotídeos. Uma entrevista com uma pesquisadora principal desta pesquisa pode ser lida, ainda em inglês, aqui. Para esta pesquisa serão escolhidas crianças acima dos 5 anos e que ainda deambulam. Se você tiver conhecimento de crianças que possam se enquadrar nesta pesquisa mais informações poderão ser obtidas pelo e-mail feder2005@gmail.com

Japão - o uso de oligonucleotídeos tem sido testados para tratamento da distrofia muscular de Duchenne; nesta pesquisa foi identificada uma substância, denominada TG003 que in vitro foi capaz de produzir o salto do exon 31 e corrigir a mutação do gene da distrofina, levando a produção de uma proteína, que apesar de incompleta, pode melhorar a sintomatologia da distrofia muscular de Duchenne.

Japão - a gentamicina é uma droga já testada na mutação de ponto (mutação sem sentido) da distrofia muscular de Duchenne. No entanto a droga só pode ser usada por via venosa com alguns efeitos colaterais que dificultam o seu uso. Nesta pesquisa a droga foi colocada em um lipossoma, uma particula gordurosa, capaz de conduzir a droga até os músculos. Os resultados obtidos foram significativos com redução da toxicidade.

USA - neste congresso, o maior em terapia gênica no mundo, serão apresentadas as recentes pesquisas na área; a maioria destas pesquisas são experimentais em cães e camundongos com distrofia muscular. O único estudo em humanos, já divulgado em outros congressos, estuda em fase 1 a terapia gênica em pacientes com distrofia tipo cinturas, demonstrando segurança no tratamento.

Espanha - em complemento a pesquisa divulgada em 2010 que demonstrou que a melatonina em doses elevadas pode ser útil na distrofia muscular de Duchenne a mesma população foi estudada com relação ao stress oxidativo. A pesquisa foi feita com os globulos vermelhos destes pacientes. Os resultados demonstraram uma redução do stress oxidativo aos valores normais após um tratamento de 9 meses com a melatonina. O resumo em inglês pode ser lido abaixo:

(Clinical Biochemistry, 2011)  Melatonin treatment counteracts the hyperoxidative status in erythrocytes of patients suffering from Duchenne muscular dystrophy

Mariam Chahbouni, Germaine Escames, Luis C. López, Belén Sevilla, Carolina Doerrier, Antonio Muñoz-Hoyos, Antonio Molina-Carballo  and Darío Acuña-Castroviejo - Spain

Abstract:

Objectives: To analyzed whether the antioxidant melatonin could reduce the hyperoxidative status in the blood of patients with Duchenne's previous termmuscular dystrophy.next term

Design and methods: Ten patients aged 12.8 ± 0.9 years were treated with melatonin (60 mg at 21:00 h plus 10 mg at 09:00 h) for 9 months, and erythrocyte markers of oxidative stress were determined at 3, 6, and 9 months of treatment. Healthy age- and sex-matched subjects served as controls.

Results: Prior to treatment, the patients had higher glutathione disulfide/glutathione ratio and higher glutathione transferase and superoxide dismutase activities, and lower glutathione reductase activity than controls. After 3 months of melatonin treatment, the hyperoxidative status of these patients was counteracted, being reduced to the normal redox state between 3 and 9 months.

Conclusion: These results, together with the reduction in the inflammatory process and in muscle injury recently reported in the same patients, support the efficacy of melatonin therapy in DMD patients.

 

USA - nesta pesquisa os autores estudaram uma droga inibidora da miostatina isoladamente e associada ao ácido ursadesoxacólico que inibe mediadores inflamatórios. A inibição da miostatina acarreta aumento da massa muscular mas sem alteração da força muscular; a associação da inibição da miostatina com o ácido ursadesoxacólico acarreta também aumento da força muscular.

Canadá - fraturas devido a osteoporose são frequentes em Duchenne e a dor pode ser limitante da qualidade de vida. Nesta pesquisa os autores testaram o bifosfonato por via venosa em dose única anual em 7 pacientes com Duchenne. Após 12 meses os autores observaram melhora da densitometria óssea, da dor e da morfometria da coluna. Este trabalho foi apresentado no Congresso Americano de Endocrinologia em 2010.

Japão - trata-se de uma pesquisa promissora para ser realizada em seres humanos e que poderia retardar ou evitar a necessidade de ventilação não invasiva na distrofia muscular de Duchenne. Camundongos com distrofia muscular receberam por via abdominal injeções no músculo diafragma de um vetor viral carregando o gene da distrofina. Os animais tratados apresentaram siginificativa expressão da distrofina e melhora da função respiratória.

USA - neste congresso de ciências básicas serão apresentadas diversas pesquisas envolvendo a distrofia muscular; a maior parte delas que não reverterão a curto prazo em tratamentos para esta doença; uma das pesquisas mais promissoras em termos de tratamento a curto prazo já foi apresentada anteriormente:o uso do sildenafil (Viagra) em camundongos com distrofia muscular; outra pesquisa também promissora estuda os agonistas dos receptores da serotonina em camundongos com distrofia muscular.

Holanda - os oligonucleotídeos tem sido testados para corrigir o gene da distrofina; nesta pesquisa foram utilizados em 12 pacientes com distrofia muscular de Duchenne por injeções semanais por via subcutãnea. A irritação no local de aplicação foi o efeito colateral mais frequente, sendo que alguns pacientes apresentaram perda de proteína na urina e aumento da alfa 1 microglobulina urinária. em 10 pacientes a expressão da distrofina foi observada em 60 a 100% das fibras musculares após o tratamento . Houve um discreto aumento da capacidade de caminhar. Os estudos irão prosseguir com maior número de pacientes. IMPORTANTE: os estudos nesta nova fase serão multicêntricos, em diversos países, e pacientes brasileiros poderão ser incluídos.

USA - idebenone é uma droga anti-oxidante que aumenta a energia das células. Neste estudo a droga foi usada por um ano na dose de 450mg em 13 pacientes com Duchenne e os resultados foram comparados com pacientes sem o uso da medicação. Os autores observam um significante aumento da capacidade respiratória. Apesar do número de indivíduos estudados os resultados são promissores e prosseguem atualmente nos Estados Unidos com um número maior de pacientes.

São Paulo - no dia 12 de março o grupo de pais e portadores de distrofia muscular realizou uma reunião científica com os pesquisadores do GRMD Brasil; neste grupo realizam-se pesquisas experimentais em camundongos e cães para melhorar a qualidade de vida e retardar a evolução da distrofia muscular. Foram apresentadas as pesquisas já realizadas e as que estão em planejamento. Os pais puderam ser ouvidos, oferecendo sugestões e comentando as pesquisas. Um pequeno vídeo do evento poderá ser visto aqui.

França - muitas drogas conhecidas, aprovadas para utilização em outras doenças, podem ser úteis no tratamento das distrofias musculares. Os pesquisadores selecionaram 21 dentre 300 drogas já testadas e administraram em camundongos com uma forma de distrofia muscular; cada droga foi testada em duas doses diferentes. Dentre todas as drogas testadas os melhores resultados foram obtidos com antidepressores tricíclicos (imipramina e amitriptilina), usados no tratados de depressão. O resumo em inglês desta pesquisa pode ser lido abaixo:

 (Neuromuscular Disorders, 2011) Pre-clinical study of 21 approved drugs in the mdx mouse

Maïté Carre-Pierrat, Aude Lafoux, Guillaume Tanniou, Lucie Chambonnier, Alexandra Divet, Francoise Fougerousse, Corinne Huchet-Cadiou and Laurent Ségalat - France

Duchenne muscular dystrophy,next term a genetic disease caused by the absence of functional dystrophin, remains without adequate treatment. Although great hopes are attached to gene and cell therapies, identification of active small molecules remains a valid option for new treatments.We have studied the effect of 20 approved pharmaceutical compounds on the muscles of dystrophin-deficient mdx5Cv mice. These compounds were selected as the result of a prior screen of 800 approved molecules on a dystrophin mutant of the invertebrate animal model Cænorhabditis elegans. Drugs were administered to the mice through maternal feeding since 2 weeks of life and mixed in their food after the 3rd week of life. The effects of the drugs on mice were evaluated both at 6 weeks and 16 weeks. Each drug was tested at two concentrations. Prednisone was added to the molecule list as a positive control. To investigate treatment efficiency, more than 30 histological, biochemical and functional parameters were recorded. This extensive study reveals that tricyclics (Imipramine and Amitriptyline) are beneficial to the fast muscles of mdx mice. It also highlights a great variability of responses according to time, muscles and assays.

USA - neste congresso serão apresentadas diversas pesquisas relacionadas com o tratamento das distrofias musculares. Os resultados clínicos que estão mais próximos de se tornarem tratamentos são os que utilizam os oligonucleotídeos para tratamento da distrofia muscular de Duchenne. Há alguns estudos iniciais com drogas em Duchenne, terapia gênica em distrofia tipo cinturas, estudos experimentais, populacionais, etc.

Itália - neste encontro de especialistas foram discutidos os aspectos endócrinos da distrofia muscular de Duchenne. Os autores sugerem uma atitude mais ativa no tratamento e prevenção destas alterações.As principais conclusões são:

1) Não há evidências que a doença cause baixa estatura, que pode ocorrer por uso de corticóides. Frequentemente não se mede a altura dos pacientes o que dificulta o acompanhamento. Se o uso do hormônio do crescimento for decidido, deve-se estabelecer um protocolo e uma meta de crescimento.

2) Atraso ou supressão da puberdade pode ser observada com em outras doenças crônicas ou pelo uso de corticóides. O uso de medicações para estimular a puberdade deve ser decidido individualmente. Alterações psicológicas decorrentes do atraso do crescimento e da puberdade devem ser avaliados, especialmente nesta fase em que a comparação com outros pode ser muito importante.

3) Ganho de peso é frequente pelo uso de corticóides e pela mobilidade reduzida. Controle dietético rigoroso deve ser estabelecido. Metabolismo da glicose deve ser estudado e na presença de resistência a insulina o tratamento com metformina pode ser instituído.

4) Atenção a saúde óssea para prevenção da osteoporose, pelo risco aumentado de fraturas. Sugere-se o acompanhamento dietético a realização de exames como a densitometria óssea. A suplementação de cálcio, vitamina D e o uso de bifosfonados foram também recomendados, apesar da ausência de estudos controlados.

 

Itália - como os corticóides permanecem como a melhor opção de tratamento para a Distrofia Muscular de Duchenne apesar dos seus efeitos colaterais, os autores testaram a associação da alfa-metil-prednisolona e da taurina esperando encontrar um tratamento que permita reduzir a dose e os efeitos colaterais dos corticóides. Os resultados funcionais desta associação foram positivos  com aumento da força e do equilíbrio do cálcio celular; no entanto, as alterações patológicas dos músculos e os níveis séricos da CK não se alteraram com a associação da taurina aos corticóides.

USA -  A losartana é uma droga utilizada para tratamento da hipertensão arterial; estudos prévios em camundongos e cães já tinham demonstrado seu efeito em reduzir a fibrose dos músculos com distrofia muscular. Este estudo confirma que a droga losartana reduz a fibrose do músculo cardíaco e dos músculos esqueléticos e além disso aumenta a função cardíaca dos camundongos com distrofia muscular. O resumo em inglês pode ser lido abaixo:

 (Journal of Cardiovascular Pharmacology and Therapeutics, Mar 2011; 16: 87 - 95) Losartan Decreases Cardiac Muscle Fibrosis and Improves Cardiac Function in Dystrophin-Deficient Mdx Mice

Christopher F. Spurney, Arpana Sali, Alfredo D. Guerron, Micaela Iantorno, Qing Yu, Heather Gordish-Dressman, Sree Rayavarapu, Jack van der Meulen, Eric P. Hoffman, and Kanneboyina Nagaraju - USA

Recent studies showed that chronic administration of losartan, an angiotensin II type I receptor antagonist, improved skeletal muscle function in dystrophin-deficient mdx mice. In this study, C57BL/10ScSn-Dmdmdx/J female mice were either untreated or treated with losartan (n = 15) in the drinking water at a dose of 600 mg/L over a 6-month period. Cardiac function was assessed via in vivo high frequency echocardiography and skeletal muscle function was assessed using grip strength testing, Digiscan monitoring, Rotarod timing, and in vitro force testing. Fibrosis was assessed using picrosirius red staining and Image J analysis. Gene expression was evaluated using real-time polymerized chain reaction (RT-PCR). Percentage shortening fraction was significantly decreased in untreated (26.9% ± 3.5%) mice compared to losartan-treated (32.2% ± 4.2%; P < .01) mice. Systolic blood pressure was significantly reduced in losartan-treated mice (56 ± 6 vs 69 ± 7 mm Hg; P < .0005). Percentage cardiac fibrosis was significantly reduced in losartan-treated hearts (P < .05) along with diaphragm (P < .01), extensor digitorum longus (P < .05), and gastrocnemius (P < .05) muscles compared to untreated mdx mice. There were no significant differences in skeletal muscle function between treated and untreated groups. Chronic treatment with losartan decreases cardiac and skeletal muscle fibrosis and improves cardiac systolic function in dystrophin-deficient mdx mice.

 

USA - o uso de corticóides ainda é considerado o melhor tratamento da distrofia muscular de Duchenne. O aumento do óxido nítrico também já demonstrou em camundongos a capacidade de melhorar os músculos com distrofia muscular. Nesta pesquisa os camundongos foram tratados com prednisona, um tipo de corticóide, e dois tipos de medicações capazes de doar óxido nítrico para os músculos. O tratamento associado apresentou resultados melhores do que os obtidos apenas com corticóide. O resumo em inglês pode ser lido abaixo:

(Am J Physiol Cell Physiol, Jan 2011) Nitric-oxide donors improve prednisone effects on muscular dystrophy in the mdx mouse diaphragm

Wataru Mizunoya, Ritika Upadhaya, Frank J. Burczynski, Guqi Wang, and Judy E Anderson

In Duchenne muscular dystrophy, palliative glucocorticoid therapy can produce myopathy or calcification. Since increased nitric oxide (NO) synthase activity in dystrophic mice promotes regeneration, the outcome of two NO-donor drugs, MyoNovin (M) or isosorbide dinitrate (I), on the effectiveness of the anti-inflammatory drug, prednisone (P, in alleviating progression of dystrophy was tested. Dystrophic mdx mice were treated (18 days) as: controls or with an NO-donor ± prednisone. Fiber permeability and DNA synthesis were labeled by Evans blue dye (EBD) and bromodeoxyuridine uptake, respectively. Prednisone decreased body-weight gain; M increased quadriceps mass and I increased heart mass. Prednisone increased fiber permeability (%EBD+ fibers) and calcification in diaphragm. Treatment with NO-donors plus prednisone (M+P, I+P) reduced the %EBD+ fibers and calcification vs. P alone. The %EBD+ fibers in M+P diaphragm did not differ from control. NO-donor treatment reduced proliferation and the population of c-met+ cells, and accelerated fiber regeneration. Concurrent with prednisone, NO-donor treatment suppressed two important detrimental effects of prednisone in mice, possibly by accelerating regeneration, re-balancing satellite cell quiescence and activation in dystrophy, and/or increasing perfusion. Results suggest NO donors could improve current therapy for DMD.

Brasil - o gene da distrofina tem 79 exons; as mutações podem atingir qualquer um destes exons; um dos tratamentos mais pesquisados atualmente é o uso de oligonucleotídeos para suplantar o defeito genético e produzir uma proteína defeituosa mas que pode melhorar os sintomas da doença. Há estudos com oligonucleotídeos polivalentes para serem utilizados em qualquer tipo de mutação, mas as pesquisas que estão mais avançadas são as dos oligonucleotídeos para o exon 51. Esta semana o Laboratório GSK divulgou o início do estudo multicêntrico,  fase 3, das pesquisas com estes oligonucleotídeos. Nesta fase da pesquisa só serão incluídas pessoas com Duchenne que ainda andam. Se os resultados forem positivos a droga será liberada no mundo todo e os doentes brasileiros não poderão utilizar porque não sabem o tipo de mutação. Inclusive muitos pacientes que hoje já poderiam participar destes estudos estarão impedidos se não souberem o tipo de mutação que apresentam. Portanto a informação sobre o tipo de mutação será muito importante no tratamento.

São Paulo - informe recebido da OAPD: A Organização de Apoio aos Portadores de Distrofias convida todos a participarem da reunião de portadores, cuidadores e profissionais de saúde. Os principais objetivos da reunião são:
- Formar um grupo de pessoas interessadas em distrofia;
- Permitir a troca de experiências e conhecimento;
- Informar e orientar distróficos e cuidadores;
- Apresentar as ações realizadas pela OAPD.
Data: 29/01/2011 – Horário: Das 10hs ás 14hs. Local: Câmara Municipal de São Paulo – Sala Oscar Pedroso Horta - 1º subsolo
Endereço: Viaduto Jacareí, 100 – Bairro: República

USA - além dos corticóides utilizados no tratamento das distrofias musculares a própria inatividade na doença mais avançada pode levar a comprometimento ósseo. Nesta pesquisa em camundongos jovens os autores observaram maior fragilidade óssea em relação aos camundongos normais. Isto demonstra que as alterações ósseas são presentes na doença mesmo sem uso de corticóides e mesmo antes da inatividade. O resumo em inglês pode ser lido abaixo:

 (Neuromuscular Disorders, 2011) Bone is functionally impaired in dystrophic mice but less so than skeletal muscle  

Susan A. Novotny, Gordon L. Warren, Angela S. Lin, Robert E. Guldberg, Kristen A. Baltgalvis, Dawn A. Lowe -USA

The primary purpose of this study was to determine if tibial bone strength is compromised in dystrophic mice and if so, what geometric and material properties contribute. Results of three-point bending tests showed that tibia of mdx and dko (dystrophin- and utrophin-deficient) mice had up to 50% lower strength and stiffness compared to wild-type mice. Micro-computed tomography indicated that dystrophic tibia had reductions of 6–57% in cortical cross-sectional moment of inertia and cross-sectional area. Metaphyseal trabecular bone morphometry was also altered up to 78% in dystrophic mice. Bone-to-muscle functional ratios (i.e., three-point bending measures:muscle strength) indicated that bone strength was relatively high in 7-week-old dystrophic mice compared to muscle strength, but ratios were similar to wild-type mice by 24 months of age. Young dystrophic mice have compromised bone strength; these modelsmay be useful for designing therapeutic regimens aimed at improving the skeleton.

Canadá -  bifosfonados são drogas utilizadas para tratamento de pessoas com osteoporose; os corticóides usados no tratamento da distrofia muscular de Duchenne aumentam os riscos de osteoporose. Os pacientes com Duchenne e tratados por pelo menos um ano com corticóides foram analisados retrospectivamente, sendo que 16 deles usaram bifosfonados. Os pacientes tratados corticóides e bifosfonados tiveram maior sobrevida do que os que receberam apenas corticóides. A população estudada foi muito pequena mas os resultados foram favoráveis à introdução dos bifosfonados com o uso de corticóides.

USA - estes pesquisadores apresentam os resultados do tratamento de camundongos com distrofia muscular com o  oligonucleotideos por um ano (duas vezes por semana). Houve aumento da expressão da distrofina nos músculos e melhora das alterações patológicas dos músculos. No coração também houve melhora da função apesar da expressão da distrofina ser baixa. Os resultados foram dose dependente.

USA - biglican é uma proteína da parte externa das membranas celulares. Ela tem a capacidade de atrair a utrofina para a membrana celular. A utrofina é uma proteína exerce uma função semelhante a distrofina na vida intrauterina. Neste experimento a administração de um biglican sintético causou melhora da força muscular e melhora das alterações patológicas musculares dos camundongos tratados. Nestes animais houve um aumento da utrofina na membrana celular. A administração de biglican pode ser uma alternativa interessante para tratamento da distrofia muscular de Duchenne/Becker.

USA - pacientes com distrofia muscular de Duchenne podem apresentar a doença com sintomas mais severos ou brandos, mais precoces ou mais tardios. Os pesquisadores procuram marcadores para identificar estes grupos de doentes. Estudando uma população grande de pacientes com Duchenne e separados de acordo com doença leve ou severa identificaram que a mutação do gene SPP1 da osteopontina é que pode determinar a variabilidade da evolução da doença. Seria possível modificar a expressão deste gene para melhorar a evolução da doença? Não há respostas até o momento. O resumo em inglês pode ser lido abaixo:

(Neurology,2011) SPP1 genotype is a determinant of disease severity in Duchenne muscular dystrophy

E. Pegoraro, E.P. Hoffman, L. Piva, B.F. Gavassini, S. Cagnin, M. Ermani, L. Bello, G. Soraru, B. Pacchioni, M.D. Bonifati, G. Lanfranchi, C. Angelini, A. Kesari, I. Lee, H. Gordish-Dressman, J.M. Devaney, C.M. McDonald, and On behalf of the Cooperative International Neuromuscular Research Group

Objective: Duchenne muscular dystrophy (DMD) is the most common single-gene lethal disorder. Substantial patient–patient variability in disease onset and progression and response to glucocorticoids is seen, suggesting genetic or environmental modifiers

Methods: Two DMD cohorts were used as test and validation groups to define genetic modifiers: a Padova longitudinal cohort (n = 106) and the Cooperative International Neuromuscular Research Group (CINRG) cross-sectional natural history cohort (n = 156). Single nucleotide polymorphisms to be genotyped were selected from mRNA profiling in patients with severe vs mild DMD, and genome-wide association studies in metabolism and polymorphisms influencing muscle phenotypes in normal volunteers were studied

Results: Effects on both disease progression and response to glucocorticoids were observed with polymorphism rs28357094 in the gene promoter of SPP1 (osteopontin). The G allele (dominant model; 35% of subjects) was associated with more rapid progression (Padova cohort log rank p = 0.003), and 12%–19% less grip strength (CINRG cohort p = 0.0003).

Conclusions: Osteopontin genotype is a genetic modifier of disease severity in Duchenne dystrophy. Inclusion of genotype data as a covariate or in inclusion criteria in DMD clinical trials would reduce intersubject variance, and increase sensitivity of the trials, particularly in older subjects.

USA -  os autores fornecem uma nova teoria para explicar a degeneração muscular em Duchenne; os camundongos mdx apesar de não apresentarem a proteína distrofina não tem a mesma fraqueza muscular do homem e do cão. Não havia uma explicação bem aceita até o momento. Os autores identificaram que os camundongos possuem telômeros mais longos; telômeros protegem cromossomos da degeneração. Os camundongos mdx e com telômeros mais curtos apresentam a doença muita mais severa. Além disso os telômeros mais curtos levam a uma exaustão das células tronco musculares impedindo a regeneração dos músculos. Por esta pesquisa a cura da doença só ocorrerá definitivamente se os tratamentos levarem a restauração das células tronco musculares.

Japão - os autores fizeram um estudo retrospectivo da sobrevida dos pacientes com Duchenne no Japão. A ventilação não invasiva, o auxílio a tosse, o uso de medicações protetoras cardíacas entre outros cuidados causaram  um signifcativo aumento da sobrevida em relação aos pacientes que no passado eram tratados com ventilação invasiva.

Japão - os pesquisadores identificaram uma droga que diminui os níveis de prostaglandina D2 nos músculos, uma substância relacionada com a inflamação nos músculos. Os animais tratados melhoraram a capacidade de regeneração muscular. Os estudos poderão ser iniciados em humanos nos próximos anos. A pesquisa foi apresentada em um congresso nesta semana no Japão.

França - 9 pacientes com distrofia tipo cinturas por deficiência em gama-sarcoglican participaram da pesquisa; eles receberam uma injeção de um vírus contendo o gene deficiente em um músculo do antebraço; após 30 dias todos desenvolveram reação imune ao vírus. Eles usaram vários métodos para avaliar o resultado e observam a expressão da proteína defeituosa nestes pacientes. Não houve efeitos colaterais. Tratá-se de um estudo inicial, fase 1, para determinar a dose mais indicada para as próximas etapas da pesquisa.

Campinas - neste artigo já previamente divulgado e agora publicado na íntegra os autores estudam o ácido eicosapentaenóico, uma gordura presente nos peixes de água fria e suplementos nutricionais  em camundongos com distrofia muscular; os animais tratados apresentaram redução do TNf-alfa que se relaciona com a agressão muscular e menor degeneração muscular demosntrando o potencial da droga como tratamento das distrofias musculares.

Campinas - suramin inibe a citocina TGF-beta1, relacionada com a fibrose muscular na distrofia. Camundongos tratados com suramin apresentaram menor fibrose e necrose muscular em todos os músculos estudados, exceto o coração; os animais tratados apresentaram  melhor resistência ao exercício. O estudo demonstra a importância de inibir a TGF-beta1 para melhorar os sintomas da distrofia muscular.

Suécia - o MG-132 é um inibidor do proteasoma que já foi testado em outras formas de distrofia. Neste experimento em camundongos deficientes em laminina alfa2, uma forma de distrofia congênita. Nestes animais o tratamento com MG-132 melhorou a força muscular, a sobrevida e as atividades locomotoras.

USA - camundongos jovens, não portadores de distrofia muscular,  foram submetidos a tratamento com células tronco musculares após uma lesão no músculo de uma das pernas. Os animais tratados apresentaram melhora da lesão e aumento da massa muscular que persistiu até o envelhecimento. Esta pesquisa demonstra o potencial do uso das células tronco em distrofias musculares.

Reino Unido - muitos tratamentos genéticos em camundongos mostram resultados positivos nos músculos dos membros e no diafragma, sem causar nenhum efeito direto no músculo cardíaco. Nesta pesquisa os autores observaram que o tratamento que melhora os músculos esqueléticos e o diafragma melhora indiretamente a função cardíaca.

Holanda - pesquisadores europeus e representante do grupo de pais americanos publicam este artigo no qual explicam a necessidade de estudos detalhados e seguros antes da liberação de novos tratamentos como o que utiliza os oligonucleotídeos; eles também criticam a iniciativa de tratamentos individualizados, utilizando drogas não comprovadas. Eles insistem que apesar de demorados estes estudos são necessários. No entanto eles esquecem o lado dos pacientes que aguardam ansiosamente por tratamentos que apesar de promissores nunca estarão disponíveis em pouco tempo. Na minha opinião a pressa dos pesquisadores não é a mesma pressa dos pacientes e seus familiares. O maior risco de ter a doença neuromuscular é não se sentir tratado e ficar aguardando indefinidamente por uma cura que está demorando muito para chegar.

Brasil -  a Eugenia punicifolia, conhecida popularmente como "pedra-ume caá" e distribuida largamente na Amazônia foi testada em camundongos com distrofia muscular e submetidos a lesão muscular; o extrato tem ação anti-inflamatória; os animais tratados apresentaram menor inflamação, maior regeneração sem aumento da fibrose muscular.

USA - este é um estudo inicial da terapia gênica em pacientes com distrofia tipo cinturas; três pacientes com deficiência de alfa sarcoglican receberam um injeção de um vetor viral levando o gene para um músculo específico. Após 6 meses este músculo foi biopsiado. Em dois pacientes havia a expressão da proteína sarcoglican no músculo tratado, demosntrando a viabilidade deste tipo de tratamento.

USA - muitas pesquisas demonstram que os radicais livres podem contribuir para a lesão muscular da distrofia. Nesta pesquisa o autor criou um camundongo que apresentava uma expressão aumentada da catalase, uma enzima que pode prevenir as alterações do stress oxidativo. Os músculos destes camundongos apresentaram força muscular maior do que os demais camundongos com distrofia, demosntrando a importância de evitar a formação de radicais livres nesta doença.

USA -  o losartan é um anti-hipertensivo que inibe a angiotensina II; diversos trabalhos em camundongos demonstraram a capacidade da droga em inibir a fibrose muscular de camundongos com distrofia muscular. Nesta pesquisa foram utilizados camundongos deficientes de delta-sarcoglican (um modelo experimental de distrofia tipo cinturas). O tratamento com losartan reduziu a fibrose muscular, aumentou a atividade motora e melhorou as alterações do sistema nervoso autônomo. O resumo em inglês pode ser lido abaixo:

 (Hypertension, 2010) Angiotensin II Contributes to Skeletal Muscle Fibrosis, Reduced Locomotor Activity and Autonomic Dysfunction in delta-Sarcoglycan Deficient Mice with Muscular Dystrophy

Rasna Sabharwal, Robert M Weiss, Univ Iowa, Iowa City, IA; Kathy Zimmerman, Vet Affairs
Med Ctr, Iowa City, IA; Mark W Chapleau; Univ Iowa, Iowa City, IA

Sarcoglycan mutations cause muscular dystrophy and dilated cardiomyopathy. We recently reported that sarcoglycan delta deficient (Sgcd / ) mice exhibit reduced locomotor activity and autonomic dysfunction at a young age (11-12wks) prior to development of left ventricular (LV) dysfunction (FASEB J, 2008). We hypothesized that angiotensin II (Ang II) contributes to
skeletal muscle and autonomic dysfunction in Sgcd / mice at this young age. Control and Sgcd / mice were treated with Ang II type 1 receptor (AT1R) blocker losartan (10mg/kg/day, drinking water) for 8 wks beginning at 3 wks of age. Blood pressure (BP), heart rate (HR), activity (telemetry), baroreflex sensitivity (BRS, sequence technique), cardiac vagal and sympathetic tone (HR responses to atropine, propranolol), LV function (echocardiography), and AT1R expression (immunofluorescence) and fibrosis (Masson stain) in skeletal muscle were measured. Comparisons were made between treated and untreated mice. Losartan restored
locomotor activity, decreased HR and reversed autonomic dysfunction in Sgcd / mice while not affecting these measures in control mice (Table). The improved functions were associated with decreases in AT1R expression and fibrosis in Sgcd / skeletal muscle, and occurred independently of changes in LV function.

Summary: Treatment of young Sgcd / mice with losartan reduced AT1R expression and fibrosis in skeletal muscle and normalized locomotor activity and autonomic regulation. We conclude that Ang II contributes to the skeletal muscle and autonomic dysfunction, perhaps via abnormal sensory or cytokine signaling from dystrophic skeletal muscle to brain.

USA - os autores pesquisaram os efeitos do sildenafil (viagra) no tratamento de camundongos com distrofia muscular em comparação com camundongos que não tinham a doença genética; nos camundongos normais não houve alteração; nos camundongos com distrofia muscular houve aumento da função cardíaca e reversão rápida dos sintomas em poucos dias após a introdução da medicação. Os resultados demonstram que o viagra pode ser efetivo para reversão dos sintomas iniciais e tardios da disfunção cardíaca da distrofia muscular.

USA - a droga ataluren tem sido testada somente para tratamento da mutação sem sentido (mutação de ponto) das doenças genéticas; no começo do ano os resultados da fase IIb tinham sido apresentados e como não foram muito positivos os novos estudos da droga foram suspensos. Os resultados foram revistos e estudados com melhor detalhamento estatístico e os resultados foram os seguintes: a dose mais alta não teve efeito benéfico como já havia sido descrito; os meninos tratados com a dose mais baixa apresentaram uma perda da capacidade de andar menor do que os que não foram tratados (grupo controle); apesar da droga não ter conseguido aumentar a força muscular este resultado foi considerado positivo e pode permitir que novos estudos possam prosseguir em 2011.

Holanda e Estados Unidos - citocinas da família BMP são inibidoras da diferenciação miogênica e impedem o desenvolvimento muscular. O uso de antagonistas da BMP melhoram as alterações patológicas dos camundongos com distrofia muscular.

África do Sul - nesta pesquisa o tratamento com antioxidantes, coenzima Q10 e resveratrol, foi realizado em camundongos com uma forma mais severa de distrofia muscular; os animais tratados apresentaram melhora das alterações musculares com redução dos marcadores de inflamação.

USA - muitos pais, no mundo todo, procuram tratamentos alternativos para a distrofia muscular; alguns chegam a abandonar o tratamento médico convencional. Pensando nos riscos de atitudes como esta o Parent Project USA, entidade de pais de pessoas com Distrofia Muscular de Duchenne lançou este alerta. O tratamento alternativo que tem causado muita discussão é  vendido no Texas e estimularia a circulação e melhoraria a força muscular. O equipamento é caro e a pessoa precisar viajar até a cidade de Corpus Christi para aprender a manusear o equipamento. Apesar de não ter a aprovação do FDA o número de pessoas utilizando o equipamento e a fila para adquirí-lo é muito grande. A tradução deste alerta foi feita pelo Marcelo D. P de OLiveira da Acadim.

Europa - os autores fazem uma revisão das proncipais linhas de pesquisa para tratamento das doenças neuromusculares, ressaltando os objetivos do tratamento e os principais efeitos colaterais já observados.

USA - os autores apresentaram os resultados do uso de um vetor viral carregando o minigene da distrofia; seis pacientes com Duchenne receberam o tratamento, não apresentando resultado na expressão da proteína no músculo; no entanto, os pacientes apresentaram linfócitos T contra a proteína distrofina; dois destes pacientes já tinham estas células antes do tratamento; a conclusão é que a reação do organismo contra a proteína distrofina pode prejudicar o resultado do tratamento e pode inviabilizar várias tentativas de tratamento da doença. É possível também que estas células podem contribuir para agravar a doença.

USA - neste congresso serão apresentados 4 pesquisas relacionadas com distrofia muscular, sendo 3 brasileiras. Drogas como a doxiciclina, um antibiótico, e o ácido eicosapentanóico, uma gordura presente em peixes de água fria e em suplementos nutricionais demonstraram em camundongos com distrofia muscular a capacidade de reduzir o processo degenerativo muscular. Em outra pesquisa a droga ácido ursadesoxicólico, uma droga com caracterísiticas anti-inflamatórias melhorou os efeitos de uma droga que aumenta a massa muscular por inibir a miostatina. Pelo que se pode observar muitas pesquisas são bem sucedidas em camundongos mas os avanços das pesquisas em humanos segue muito lentamente. Os resumos podem ser lidos abaixo:

Neuroscience 2010 - 40th Annual Meeting - November 13-17, San Diego.

1) Dystrophinopathy in mdx mice is alleviated by doxycycline, a tetracycline derivative

*H. SANTO NETO, J. ALVES PEREIRA, C. YURI MATSUMURA, A. TIEMI TANIGUTI, M. MARQUES;
Anatomia, Biologia Celular, Fisiologia, Biofisica, Univ. Estadual de Campinas UNICAMP, Campinas, Brazil

Muscle degeneration and fibrosis are associated with inflammation in dystrophic muscles of Duchenne muscular dystrophy and in the mdx mice. We evaluated the effect of doxycycline, a tetracycline derivative with anti-inflammatory and anti-apoptotic effects, on muscle degeneration in mdx mice. Mdx mice (n=20; 20 days of age) received doxycycline (n=10; 6mg/ml on drinking water) for 5 weeks, after which the diaphragm (DIA) and biceps brachii (BB) muscles were removed. Control mdx mice (n=10) received water only. Serum creatine kinase levels, an indicative of myonecrosis, were significantly decreased by doxycycline (control-mdx: 1292±223 U/l, doxycycline-mdx: 973±243 U/l; p<0.05, Student's t-test). Histological analysis showed that doxycycline decreased the inflammatory area in both muscles. Doxycycline protected against myonecrosis (3% of Evans blue dye-positive fibers in control-DIA vs 1.2% in doxycycline-DIA; in control-BB, 3.8% of Evans blue positive-fibers vs 1.0% in doxycycline-BB) and promoted a significant increase in peripheral cell nuclei fibers in both DIA and BB. Functional analyses (grip strength) showed that doxycycline did not change muscle force over time. These results indicate that doxycycline may be a possible useful therapeutic alternative to ameliorate muscular dystrophy caused by dystrophin deficiency.

2) Eicosapentaenoic acid decreases TNF and protects dystrophin-deficient muscle fibers of mdx from degeneration

*M. J. MARQUES, R. VENTURA MACHADO, A. FOGAGNOLO MAURICIO, R. FERRETTI, H. SANTO NETO;
Anatomia, Biologia Celular, Fisiologia, Biofisica, Univ. Estadual de Campinas -UNICAMP, Campinas, Brazil

The lack of dystrophin in dystrophin-deficient fibers of mdx mice and in Duchenne muscular dystrophy leads to sarcolemmal breakdown and progressive muscle degeneration. The increased production of inflammatory cytokines, such as tumor necrosis factor (TNF)-α, seems to contribute to myonecrosis. We examined whether eicosapentaenoic acid (EPA), a -3 polyunsaturated fatty acid with anti-inflammatory properties, could protect different dystrophic muscles from degeneration. Mdx mice (14 days old) received EPA (n=12; 300 mg/kg body weight; daily oral gavage, diluted in mineral oil) for 16 days, after which the sternomastoid (STN), diaphragm (DIA), tibialis anterior (TA) and biceps brachii (BB) muscles were removed. Control mdx mice (n=12) received mineral oil. EPA significantly decreased serum creatine kinase levels (control-mdx: 1208±376 U/L; EPA-mdx: 838±347 U/L; p<0.05, Student's t-test). In all muscles studied, EPA protected against myonecrosis and from changes in sarcolemma permeability leading to a significant increase in peripheral cell nucleated fibres and a concomitant decrease in Evans blue dye-positive fibres (60% of decrease in BB, 70% in DIA and STN and 80% of decrease in TA). EPA reduced the inflammatory area in the DIA (13.2±7.6% of inflammatory area in control-mdx vs 3.4±2.4% of inflammatory area in EPA-mdx; p<0.05, Student's t-test). Grip strength test showed that EPA did not change the increase in muscle strength with time observed in mdx at this age. Immunoblotting indicated that EPA significantly reduced the levels of TNF-α in all muscles studied. These results indicate that EPA has a protective action against dystrophic muscle degeneration, possibly by reducing the levels of TNF-α, supporting further investigations of EPA as a potential therapeutic agent to dystrophinopaties.

3) The effect of a soluble activin receptor type IIB on whole body tension in mdx mice is improved by co-administration of an NF-kappaB inhibitor

*C. CARLSON1, L. MCCARTHY1, K. BRUEMMER1, J. SESTI1, C. STEFANSKI1, H. CURTIS1, J. UCRAN2;
1Dept Physiol, AT Still Univ., KIRKSVILLE, MO; 2Acceleron Pharma, Cambridge, MA

The effect of in vivo administration of RAP-031, a soluble activin receptor type IIB (ActRIIB) comprised of a form of the ActRIIB extracellular domain linked to a murine Fc, with and without co-treatment with an NF-κB inhibitor on whole body tension (WBT) was examined using the mdx mouse model for Duchenne muscular dystrophy. Treatment of mdx mice with RAP-031 for 90 days produced a 41 % increase in body mass and a 42.5 % increase in forward pulling tension (FPT) exerted by the limb musculature. Consistent with RAP-031 increasing muscle strength proportionally to body weight, whole body tension (WBT), or FPT normalized for body weight, was unchanged in the RAP-031 treated group compared to vehicle treated. Similar increases in muscle mass and FPT were seen when RAP-031 was used in conjunction with the NF-κB inhibitor ursodeoxycholic acid (UDCA). In contrast to treatment with RAP-031 alone, however, WBT was increased by treatment with RAP-031 + UDCA, supporting the idea that the combination treatment produces muscle that is stronger in proportion to body weight in mdx mice, and that co-treatment with an NF-κB inhibitor may potentiate the beneficial effects of RAP-031 in increasing muscle strength. These results indicate that treatment of dystrophic mice with RAP-031 produces large increases in muscle mass that are associated with corresponding increases in the forward pulling tension exerted by the limb musculature.

4) Granulocyte colony stimulating factor (G-CSF) reduces loss of inputs to alpha-motoneurons during the course of muscular distrophy and after axotomy in mdx mice

G. F. SIMOES1, *A. L. OLIVEIRA2;
1Anat., Univ. of Campinas, Campinas, Brazil; 2Dept Anat, State Univ. Campinas - UNICAMP, Campinas, Brazil

G-CSF is a key hemopoietic factor that has also been demonstrated to have immunoregulatory properties, stimulating anti-inflammatory pathways. Such immune response regulation may positively influence synaptic stability after lesion and during the course of neuromuscular diseases, such as muscular distrophies. Thus, the aim of this study was to investigate the synapse preservation and glial reactivity in the microenvironment surrounding spinal motoneurons in a Duchenne muscular dystrophy animal model (namely the MDX mice) after treatment with G-CSF. In this way, six weeks old male MDX mice were treated with subcucaneous injections of 200 µg/kg/day of G-CSF 7 days before and 7 days after the left sciatic nerve transection. The axotomy was performed after the cycles of muscular degeneration/regeneration, previously described in such model of muscular dystrophy. C57BL/10 mice were used as controls. Seven days after surgery, the animals were sacrificied and their lumbar spinal cords processed for immunohistochemistry (antisera against MHC I - major histocompatibility complex class I, synaptophysin, GFAP - glial fibrillary acidic protein and Iba1 - ionized calcium binding adaptor protein were used) and transmission electron microscopy (TEM). Overall, G-CSF treatment was able to induce upregulation of MHC-I in both strains after axotomy, although MDX mice displayed significantly lower levels. Regarding GFAP expression, G-CSF treatment resulted in a stronger astrogliosis in MDX mice. G-CSF administration resulted in no significant alteration of the microglial reaction, as seen by the anti-Iba1 labeling. Interestingly, G-CSF treatment preserved a significant percentage of pre-synaptic inputs as seen by synaptophysin immunohistochemistry (Placebo - MDX, 4.89×103±76.00 C57BL/10, 6.76×103±108.00, p<0.001; G-CSF MDX, 9.20×103±37.00; C57BL/10, 1.05×104±104.00, p<0.01 - ipsilateral side to the lesion; integrated density of pixels/100µm2). TEM analysis revealed a ~15% greater synaptic covering in both strains after axotomy and G-CSF treatment. Also, the number of synaptic terminals/100µm in apposition to the motor neuron membrane increased after treatment (Axotomized - placebo - MDX, 33.50 ± 0.83; C57BL/10, 39.30 ± 0.49, p<0.001. Axotomized - G-CSF - MDX, 40.26 ± 1.03; C57BL/10, 48.13 ± 1.75, p>0.05). Altogether, the present results indicate that G-CSF treatment is able to reduce the retrograde effects related to the course of the muscular distrophy in MDX mice and following peripheral axotomy. This is possibly associated to the preservation of inputs to spinal motoneurons and to the regulation of the astroglial reaction and MHC I expression.

 

Canadá e Itália - os autores fazem uma revisão das pesquisas com o uso de mioblastos transplantados em músculos de pacientes com distrofia muscular de Duchenne, ressaltando a necessidade de imunossupressão para este tratamento. Este tratamento não permite o uso de mioblastos por via sistêmica, somente para injeção das células diretamente nos músculos.

Brasil - neste trabalho apresentado no Congresso Brasileiro de Genética nesta semana, a ciclosporina modificada, conhecida como Debio-025 foi utilizada em cães com distrofia muscular; os resultados preliminares demonstraram que até o momento a droga não causou melhora das alterações patólogicas dos músculos esqueléticos dos animais tratados com a droga.

Brasil - camundongos com distrofia muscular tratados com nicotina, que ativa os receptores nicotínicos da acetilcolina, apresentaram redução das citocinas inflamatórias, redução da inflamação e aumento da regeneração.

USA - inibidor concentrado Bowman Birk (BBIC) é uma enzima estraída da soja que promove redução da atrofia muscular. A droga testada em camundongos reduziu a fibrose, a miostatina, aTGF beta 1 (citocina causadora de fibrose), aumentou a massa e a força muscular. É uma droga que deveria ser testada em seres humanos para retardar a evolução da doença.

USA - a ativação da calpaína piora as alterações patológicas da distrofia muscular; os autores experimentaram um composto a base de leupeptina com carnitina em camundongos com distrofia muscular; a administração por um mês e por seis meses não produziu melhora das alterações patológicas dos camundongos com distrofia muscular.

Itália - os autores estudaram um modelo experimental com distrofia tipo cinturas em hamster. Os animais tratados com dieta enriquecida em ácidos graxos tipo omega-3 apresentaram menor alteração muscular do que os animais do grupo controle, demonstrando experimentalmente que uma modificação simples da dieta pode contribuir para melhorar as alterações musculares ou retardar o seu aparecimento.

USA - um dos problemas que precisam ser resolvidos com a terapia gênica é a resposta imunológica ao tratamento; neste experimento em camundongos com distrofia muscular os animais receberam uma radioterapia prévia a terapia gênica para reduzir a resposta imunológica. Com a radioterapia prévia a resposta imunológica foi retardada. O uso de imunossupressores provavelmente será necessário quando a terapia gênica estiver disponível.

Japão - nesta edição deste congresso serão apresentadas mais de 270 pesquisas em doenças neuromusculares; comparando os resumos apresentados em 2009 com os que serão apresentados neste ano não há nenhum avanço significativo com relação ao tratamento das distrofias musculares. Os resumos podem ser vistos abaixo:

wms2010_1      wms2010_2      wms2010_3      wms2010_4      wms2010_5       wms2010_6       wms2010_7    

wms2010_8      wms2010_9      wms2010_10    wms2010_11    wms2010_12    wms2010_13    wms2010_14  

wms2010_15    wms2010_16    wms2010_17    wms2010_18    wms2010_19    wms2010_20    wms2010_21  

wms2010_22    wms2010_23    wms2010_24    wms2010_25    wms2010_26    wms2010_27

Escócia, Itália e Brasil - trata-se de uma extensa revisão sobre o uso de drogas imunossupressoras no tratamento da distrofia muscular de Duchenne; muitos tratamentos com células tronco, terapia gênica e transplante de mioblastos precisarão ser realizados com a utilização de drogas imunosspuressoras e portanto é importante conhecer o seu efeito na doença. São relatados os estudos em camundongos e em estudos clínicos em seres humanos já realizados.

USA - este interessante artigo foi escrito por Patrick Moeschen, portador de distrofia muscular de Becker, professor de música e ativista dos direitos dos portadores de distrofia muscular. Nele ele relata sua visão sobre a doença, ressaltando a necessidade de procura do tratamento da doença, observando a visão dos profissionais da área e a visão social do problema ressaltando que é possível ter uma boa vida apesar das limitações, não se podendo esperar a chegada da cura para começar a se viver. Não é possível viver a vida toda exclusivamente para aguardar a cura sem viver cada momento do presente. É uma lição de vida para muitos pais brasileiros. A tradução do texto para o português foi feita por Marcelo D. P. de Oliveira e pode ser lida aqui.

Índia - o Nizam Institute of Medical Sciences (NIMS) iniciou o recrutamento de pacientes com Duchenne para tratamento com células tronco. Não há informações sobre a fonte das células e do protocolo do tratamento a ser instituído.

Alemanha - a ciclosporina A é uma droga imunossupressora utilizada em diversas doenças. Neste estudo realizado em três anos em vários centros de pesquisa, 153 pacientes com Duchenne foram estudados, 77 tratados com ciclosporina A. A droga sozinha ou associada aos corticóides não aumentou a força muscular, apesar de ser segura e não aumentar significantemente os efeitos colaterais. Em editorial da mesma revista comenta-se que o resultado ser negativo e decepcionante da ciclosporina A permitirá entender melhor o efeito dos corticóides; fica claro que o efeito imunossupressor dos corticóides não é o responsável pelo seu efeito benéfico e que os corticóides são ainda a melhor opção terapêutica na distrofia muscular de Duchenne.

Holanda - neste encontro realizado em novembro de 2010 os pesquisadores reunidos discutiram os aspectos relacionados com a osteoporose que acompanha os pacientes com distrofia muscular tratados com corticóides. Os aspectos mais importantes são: monitorização da ingestão de cálcio e vitamina D; monitorização dos níveis sanguíneos de vitamina D; exposição ao sol; atividades físicas; reposição de cálcio e vitamina D; densitometria óssea anual; avaliação de endocrinologista se não atingir a puberdade com 14 anos.

USA - os autores decidiram estudar o papel do fluxo sanguíneo nas alterações dos músculos com distrofia muscular; os pesquisadores construiram camundongos com distrofia muscular com capacidade aumentada de produzir vasos sanguíneos. Estes animais apresentavam menores alterações musculares e maior força do que os camundongos com apenas distrofia muscular. O estudo demonstra que a manutenção de um  bom fluxo sanguíneo para os músculos pode reduzir as alterações musculares da distrofia mesmo com a ausência da distrofina.

Canadá - o transplante de mioblastos continua sendo testado no Canadá; as células injetadas tem uma vida curta e seu uso só seria viável por injeção intramuscular; neste experimento os autores bloquearam o efeito da miostatina, uma proteína que inibe o desenvolvimento muscular. O trasnplante de mioblastos com inibição da miostatina causou um significante aumento da expressão da distrofina quando comparado com o transplante convencional de mioblastos.

Canadá - a laminina-111 está presente nos músculos esqueléticos e coração durante a fase embrionária e já demonstrou efeito positivo em camundongos com distrofia muscular. Neste estudo ela foi estudada sozinha e associada com a técnica de transplantes de mioblastos. A injeção intramuscular de laminina-111 aumenta a força muscular e a resistência. Utilizada em conjunto com o transplante de mioblastos ela reduziu o ritmo de degeneração, inflamação e regeneração. In vitro os mioblastos tratados com laminina-111 se tornam mais ativos. Os estudos com a laminina-111 e com transplantes de mioblastos prosseguem, alguns em pacientes com Duchenne.

China - 33 pacientes com distrofia muscular tipo cinturas foram submetidos a transplante de células tronco de suas próprias medulas osséas. Previamente a retirada das células houve a aplicação de uma droga para estimular a produção de células pela medula. Após o tratamento houve aumento da força muscular e reução dos níveis de CK. As informações são limitadas e o resumo em inglês pode ser lido abaixo:

(Journal of Clinical Rehabilitation Tissue Engineering Research. 13(32):6345-6348, August 6, 2009) Xu YF, Yang XF, Wu YX, Wang HM, Zhang YB, Lu NW, Shan H, Cui JP, Zhou JX, Yin FH.Transplantation of autologous bone marrow stem cells for limb-girdle muscular dystrophies in 33 cases.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu. 2009;13(32):6345-6348.

Following the agreement of Ethics Committee of the 463 Hospital of Chinese PLA, a total of 33 limb-girdle muscular dystrophy (LGMD) patients, including 27 males and 6 females, aged 6 to 46 years with the course of disease of 2 to 20 years were enrolled from the Department of Hematology and Endocrinology of the 463 Hospital of Chinese PLA from December 2007 to June 2008. Granulocyte-colony stimulating factor (G-CSF) was infused into patients, and bone marrow was collected following 4 days of mobilization. Bone marrow mononuclear cells were isolated and cultured for 7-10 days by Percoll gradient centrifugation. Cell suspension (2.48x1010/L) was prepared. Stem cells were transplanted into all over the body by intravenous infusion and extremities by intramuscular injection. The amount of mononuclear cells was (6.13+/-2.39)x108 and the amount of mesenchymal cells was (1.92+/-0.98)x108. Six months after transplantation, increased rates of bare-handed muscle force and activities of daily living (ADL) were respectively 54.5% and 81.8%. The decreased rates of serum creatine kinase and lactic acid dehydrogenase were respectively 78.8% and 81.8%. The increased rate of creatinine was 72.7%. It was indicated that transplantation of autologous bone marrow stem cells for LGMD can enhance the bare-handed muscle force and activities of daily living and improve values of serum creatine kinase, lactic acid dehydrogenase and creatinine.
 

China -  o autor relata uma caso de distrofia de Emery-Dreifus internado por infarto cerebelar e que foi tratado com células tronco mesenquimais retiradas do cordão umbilical e compatíveis imunologicamente. Houve melhora das condições clínicas e redução dos níveis de CK após o tratamento. As informações são limitadas e o resumo em inglês e pode ser lido abaixo:

(Journal  of Clinical Rehabilitation Tissue Engineering Research. 13(27):5393-5396, July 2, 2009) Allogeneic cord blood mesenchymal stem cell transplantation for treating Emery-Dreifus muscular dystrophy in one case. Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2009;13(27): 5393-5396(China)
Liao Y. - China

A male patient, aged 32 years, weighing 38 kg, was recruited at the Department of Neurology, Wuxi Second Hospital, Nanjing Medical University in February 2008. The patient had general fatigue and amyotrophy for 18 years, and recruited in the hospital 3 days following burst dizziness and vomiting. Following genetic analysis and muscle biopsy, the patient was diagnosed as having Emery-Dreifus muscular dystrophy and cerebellar infarction. HLA compatible cord blood mesenchymal stem cell (CB-MSC) transplantation was performed. The grafted CB-MSCs were from Shanghai Cord Blood Bank. The donor was HIA all-identical, Rh blood type-identical, ABO blood type-incompatible. The patient received preconditioning of busulfan + cyclophosphamide + rabbit antithymocyte globulin. The patient then received peripheral venous administration of 40 mL CB-MSCs, 10 drops/minute, with total nucleated cell number of 31.98x108. 5 weeks after transplantation, symptoms of dizziness, swallowing difficulty and regurgitation of fluid were markedly alleviated. His weight increased by 4 kg and he recovered of hand coordination to handling computer operation. 6 months following transplantation, serum creatine phosphokinase decreased from 35.79 [mu]kat/L before transplantation to 9.55 [mu]kat/L; serum creatine phosphokinase isoenzyme reduced from 18.20 [mu]kat/L before transplantation to 4.78 [mu]kat/L. Myoglobin decreased from 413.50 [mu]g/L to 213.20 [mu]g/L. Functional independence measure scores increased from 71 points to 101 points. Immunological rejection or tumorigenesis was not identified. CB-MSC transplantation can evidently decrease serum creatine phosphokinase level within a short period, and improve motor function in Emery-Dreifus muscular dystrophy patient. CB-MSC transplantation is beneficial for Emery-Dreifus muscular dystrophy, and short-term safety is reliable.

USA - trata-se de mais um estudo retrospectivo demonstrando os efeitos benéficos do uso de corticóides na distrofia muscular de Duchenne. Os meninos tratados com corticóides mantiveram a marcha por mais tempo, necessitaram de ventilação não invasiva noturna mais tardiamente e também ficaram dependentes da ventilação não invasiva significantemente mais tarde. O resumo em inglês pode ser lido abaixo:

(Am J Phys Med Rehabil 2010;89:620–624) Duchenne Muscular Dystrophy - The Effect of Glucocorticoids on Ventilator Use and Ambulation

Bach JR, Martinez D, Saulat B - USA

Objective: To describe the effect of glucocorticoid treatment on age at wheelchair dependence and at dependence on part-time       (<23 hrs/day) and continuous noninvasive mechanical ventilation. Design: In this retrospective study, patients with Duchenne muscular dystrophy who received glucocorticoid therapy were compared with those who did not for ages at wheelchair dependence and when beginning part-time (nocturnal) and continuous noninvasive intermittent positive pressure ventilation (NIV). Respiratory symptoms, end-tidal carbon dioxide, oximetry, and vital capacity were noted every 4–12 mos, and NIV was initiated for symptomatic nocturnal hypoventilation. The daily NIV use increased until some required it continuously to survive.
Results: The 117 untreated patients became wheelchair-dependent at 9.7 + 1.3 yrs of age. Four then died from cardiac failure, and five were older than 19 yrs without using NIV. The remaining 108 began nocturnal NIV at 19.2 + 3.7 yrs of age. Ninety of the 108 became continuously NIV-dependent at 21.9 + 4.5 yrs of age, and the 17 treated with glucocorticoid therapy became wheelchair-dependent significantly later at 10.8 + 1.3 yrs of age (P = 0.02). Three died from cardiac failure, and three were older than 19 yrs without using NIV. The remaining 11 began nocturnal NIV at 22.9 + 5.3 yrs of age (P = 0.05). Eight of the 11became continuously NIV-dependent at age 28.9 + 7.3 yrs (P = 0.005). Conclusions: Intermittent glucocorticoid therapy delays wheelchair dependence and may delay ventilator dependence for patients with Duchenne muscular dystrophy.

França - recentemente foi divulgado um consenso de pesquisadores estabelecendo os princípios de tratamento da distrofia muscular de Duchenne. Este grupo de pesquisadores franceses escreveu esta carta a revista discordando de alguns pontos deste consenso. Eles também utilizam corticóides no tratamento de Duchenne e reafirmam os seus benefícios mas eles acham que a doença continua evoluindo apesar do tratamento; o uso precoce dos inibidores da enzima conversora da angiotensina (como perindopril pode retardar o aparecimento da disfunção cardíaca e melhorar a evolução da doença. Estes pesquisadores começam o tratamento com este grupo de drogas em torno dos 9 anos, antes do que as alterações do exame cardiológico apareçam.

USA - Debio-025 é um inibidor da ciclofilina que pode reduzir a necrose muscular; o seu uso em camundongos com distrofia muscular mostrou melhora significante das alterações patológicas, aumento da força muscular e redução da CK com resultados melhores do que a prednisona isolada, sendo uma droga promissora para novos estudos. O resumo em inglês podem ser lido abaixo:

(Neuromuscular Disorders, 2010) Debio-025 is more effective than prednisone in reducing muscular pathology in mdx mice

Erin R. Wissing, Douglas P. Millay, Grégoire Vuagniaux, Jeffery D. Molkentin - USA

Muscular dystrophy results in the progressive wasting and necrosis of skeletal muscle. Glucocorticoids such as prednisone have emerged as a front-line treatment for many forms of this disease. Recently, Debio-025, a cyclophilin inhibitor that desensitizes the mitochondrial permeability pore and subsequent cellular necrosis, was shown to improve pathology in three different mouse models of muscular dystrophy. However it is not known if Debio-025 can work in conjunction with prednisone, or how it compares against prednisone in mitigating disease in dystrophic mouse models. Here we show that Debio-025 reduced the variations in myofiber cross-sectional areas, decreased fibrosis, and decreased infiltration of activated macrophages more efficiently than prednisone. However the use of prednisone and Debio-025 together had no additional effect on these histopathological indexes. Orally administered Debio-025 also reduced creatine kinase blood levels and improved grip strength in mdx mice after 6 weeks of
treatment, and the combination of Debio-025 with prednisone increased muscle function slightly better than prednisone alone. Thus, our results suggest that Debio-025 is as, effective as or slightly better than, prednisone in mitigating muscular dystrophy in the mdx mouse model of disease.

Itália - a droga rituximab diminui as células B e é usada em doenças inflamatórias dos músculos; como na distrofia de Miyoshi existe um infiltrado inflamatório os autores trataram dois pacientes com esta droga e avaliaram o efeito após um ano. Os pacientes apresentaram aumento da força muscular sem efeitos colaterais severos.

Itália - os autores estudaram o efeito do aminoácido taurina isolado ou associado a metilprednidolona em camundongos com distrofia muscular. Os estudos da força muscular demonstram um efeito sinérgico da taurina em adição ao tratamento com corticóides; as alterações da histologia dos músculos e a dosagem da CK não apresentaram alteração em relação ao animais tratados somente com corticóides.

USA - em 2005 a Academia Americana de Neurologia recomendou o uso de corticóides a todos os pacientes com distrofia muscular de Duchenne. Os autores desta revisão revisaram as informações mais recentes do uso dos corticóides em Duchenne: aumento do tempo de deambulação de 2 a 5 anos; redução da necessidade de cirurgia para escoliose; melhora da função cardio-respiratória; postergação da necessidade de ventilação não-invasiva; aumento da sobrevida e da qualidade de vida. Apesar de alguns efeitos colaterais conhecidos os benefícios superam em muito os efeitos indesejáveis.

USA - no começo de 2010 um artigo estabeleceu algumas normas para acompanhamento de pacientes com distrofia muscular de Duchenne, destacando os exames necessários em cada fase da doença e as recomendações de tratamento para todas as complicações. Neste artigo os especialistas reunidos completam aquele trabalho demonstrando em detalhes todas as etapas do acompanhamento e tratamento das manifestações respiratórias dos pacientes com Duchenne. Seria ideal que os profissionais de saúde que acompanham os pacientes pudessem ler estas informações e revisar e atualizar seus procedimentos.

USA - esta pesquisa foi apresentada no congresso anual da Sociedade de Endocrinologia - ENDO-2010. Há muitas controvérsias com relação ao uso de hormônio do crescimento (GH) em distrofia muscular de Duchenne. O GH poderia aumentar o crescimento de adolescentes em uso de corticóides e poderia ter outros efeitos positivos na função muscular e na gordura corpórea; 29 adolescentes com Duchenne em tratamento com corticóides foram tratados com GH por 4 a 32 meses. Houve um aumento do crescimento, com redução da velocidade de ganho de peso sem alterações colaterais significativas; um menino teve resistência à insulina e dois progressão da escoliose. Os estudos devem prosseguir por mais tempo para conclusões definitivas. O resumo em inglês pode ser lido abaixo:

(Annual Meeting Endocrinology Society - ENDO-2010) Growth Hormone Improves Growth in Duchenne Muscular Dystrophy Boys with Steroid-Induced Growth Failure.

 MM Rutter, J Collins, JG Woo, SR Rose, H Sawnani, LH Cripe, KJ Kinnett, K Hor, BL Wong. Cincinnati Children's Hosp Med Ctr, Cincinnati, OH.

Background: Duchenne Muscular Dystrophy (DMD) is a progressive degenerative muscle disorder affecting 1 in 3500 boys. In the absence of a cure, daily high-dose glucocorticoids (GCs) are the mainstay of treatment, slowing disease progression and prolonging ambulation and survival. GCs cause growth failure, weight gain, absent puberty and osteoporosis, which negatively impact quality of life in DMD. Growth hormone (GH) offers potential benefit in DMD: it may help counter GC-induced growth failure, and could have positive effects on body fat, muscle strength and function. However, data regarding efficacy and safety of GH in DMD is lacking.
Objective: To evaluate efficacy and safety of GH in DMD boys with GC-induced growth failure during the first year of treatment.
Methods: We report a case-series of 29 DMD boys on daily GCs, treated in the Cincinnati Neuromuscular Comprehensive Care Center. The boys were treated with growth hormone for severe growth failure. Outcomes included growth velocity, height SD, weight, BMI, neuromuscular and cardiopulmonary function, and side effects.
Results: 29 prepubertal boys (mean age SD 12.2 2.9y) were treated with GH for 4-32m (mean 12m). They had received daily GCs for 5.5 2.2y. Peak stimulated GH levels were 6.9 3.6 ng/ml. Height z-score (mean SEM) was -3.1 0.2 and height velocity was 1.1 0.3 cm/y before GH. During the first year on GH, height velocity improved to 5.6 0.7 cm/y (p<0.0001). Baseline decline in height z-score before GH (p<0.001) was followed by stabilization at -3.0 0.2 (p=0.2) on GH. There was a trend toward reduction in rate of weight gain at 1 year (2.8 0.7 to 0.6 1.1 kg/y, p=0.3), with decreased weight z-scores from -0.6 0.3 to -1.2 0.4 (p<0.0004). BMI z-score improved from 1.3 0.2 to 0.8 0.2 (p<0.0001). There were no detrimental effects on neuromuscular or cardiopulmonary function attributable to GH. GH was well tolerated, with 3/29 experiencing side effects by 1y. One boy developed worsening insulin resistance / impaired glucose tolerance. Two boys had progression of scoliosis.
Conclusions: GH treatment of DMD boys with GC-induced growth failure improved growth during the first year. Rate of weight gain slowed for some, with improvement in BMI. GH was relatively safe, with no detrimental effects on neuromuscular and cardiopulmonary function. Further study is needed before conclusions can be drawn regarding longer-term safety and efficacy.

Canadá - esta pesquisa foi apresentada no congresso anual da Sociedade de Endocrinologia - ENDO-2010. A osteoporose é frequente em Duchenne, em especial nos que usam corticóides. A osteoporose predispõe a fraturas e o uso de bifosfonados é recomendado com tratamento para esta condição. Nesta pesquisa os autores testaram o uso de pamidronato ou zoledronato por via venosa (ambas as drogas são dadas uma vez por ano) em 7 meninos com Duchenne e fraturas em coluna, O tratamento com a droga mostrou-se eficaz com aumento da densidade óssea e redução das dores decorrentes das fraturas. Os efeitos colaterais observados foram febre (2 casos), náuseas (2 casos), dores musculares (3 casos) e hipocalcemia (2 casos). O resumo em inglês pode ser lido abaixo:

(Annual Meeting Endocrinology Society - ENDO-2010)  Effect of Intravenous Bisphosphonate Therapy among Boys with Duchenne Muscular Dystrophy and Osteoporosis: Clinical Outcomes.

AM Sbrocchi, F Rauch, V Konji, M Tomiak, P Jacob, LM Ward. Children's Hosp of Eastern Ontario, Ottawa, Canada; Shriners Hosp for Children, Montreal, Canada.

Introduction: Boys with Duchenne Muscular Dystrophy (DMD) may develop symptomatic vertebral fractures. Bisphosphonates have been used to treat the spine fragility; however, detailed analyses of the response to therapy are lacking. The objective of this study was to assess the efficacy and safety of IV bisphosphonate treatment in boys with spinal osteoporosis due to DMD.
Methods: This was a one-year, retrospective observational study of 7 boys (age 8.5-14.3 years) with DMD who had received either IV pamidronate (9 mg/kg/year) or zoledronate (0.1 mg/kg/year) to treat painful vertebral fractures. The primary outcome was change in vertebral morphometry at 12 months post-bisphosphonate initiation. Secondary outcomes included back pain status, changes in lumbar spine volumetric bone mineral density (vBMD), and adverse events.
Results: A description of the cohort is presented in the Table. All but one had received glucocorticoid therapy prior to treatment initiation, and all but one was non-ambulatory. There were 27 fracture events noted in the 7 patients at baseline; 15/27 were in the T4-T9 region. Grade 2 (moderate) and Grade 3 (severe) vertebral fractures reconstituted at 12 months, and this was associated with either improvement or complete resolution of back pain. The median spine vBMD also increased. First-dose side effects were present in 4 patients and included fever (N=2), nausea (N=2), myalgias (N=3) and hypocalcemia (N=2).
Conclusion: In boys with spinal osteoporosis and DMD, IV bisphosponate therapy administered over 12 months was associated with improved vertebral morphometry and density; similarly, there was amelioration in back pain. The therapy was generally well-tolerated.

Table. Clinical Parameters Pre- and 12 Months Post-Treatment

Clinical Characteristics

Results 12 Months Post Bisphosphonate Initiation (N=7)

 

Pre-Treatment

12 Months Post

Anthropometry

 

 

Height Z-score

-1.7 (-4.2, -0.5)

-2.0 (-3.5, -0.1)

Weight Z-score

0.4 ( -2.4, 1.8)

-1.7 (-1.9, 1.9)

Vertebral Morphometry

 

 

Genant Grade for VF Events, N (%)

 

 

Grade 0.5 = 15-19.9% loss in VH

5 (18%)

11 (41%)

Grade 1 = 20-25% loss in VH

4 (15%)

7 (26%)

Grade 2 = 25.1-40% loss in VH

14 (52%)

9 (33%)

Grade 3 = >40% loss in VH

4 (15%)

0 (0%)

Lumbar Spine Volumetric BMD (Z-score)

-1.0 (-3.0, 0.9)

-0.1 (-2.6, 1.4)

Values reported are median (min, max) unless otherwise specified. VH=Vertebral height, BMD= Bone mineral density.

USA - os autores avaliaram 150 pacientes com diversas formas de distrofia muscular com o objetivo de avaliar se o eletrocardiograma e o holter são úteis na avaliação da presença ou não de doença cardíaca; alterações do eletrocardiograma foram observadas em 65% dos pacientes e se relacionou fortemente com a presença de miocardiopatia; somente 8% dos pacientes com eletrocardiograma normal apresentavam miocardiopatia. As alterações do eletrocardiograma são precoces e podem preceder em anos o aparecimento dos sintomas. A utilização do eletrocaridiograma e holter periódicos dos pacientes pode ajudar no diagnóstico precoce. O resumo em inglês pode ser lido abaixo:

(Heart Rhythm, 2010) Electrocardiographic Abnormalities and Arrhythmias are Strongly Associated with the Development of Cardiomyopathy in Muscular Dystrophy

Anjan M. Shah, John L. Jefferies, Joseph W. Rossano, Jamie A. Decker, Bryan C. Cannon, Jeffrey J. Kim - USA

Objective: Assess the utility of electrocardiography in patients with muscular dystrophy. Background: Dilated cardiomyopathy is a well-recognized sequela of muscular dystrophy (MD). Early identification of cardiac involvement with timely therapy can favorably impact outcome. We hypothesize that electrocardiography can be a useful adjunct in the identification of DCM in MD. Methods: A retrospective review of patients with MD was performed. ECGs and Holters were analyzed to assess for association between abnormalities and the development of DCM. Results: One-hundred-fifty patients were identified. Forty-three percent of patients
(64/150) developed DCM. ECG abnormalities were found in 65% of patients and correlated well with the presence of DCM with 60/64 (94%) with DCM having an abnormal ECG vs. 38/86 (44%) without DCM (p<0.001). Only 4/52 (8%) of patients with normal ECGs had DCM. The presence of ECG abnormalities was highly sensitive (95.8%) but not specific (40.1%) to the presence of DCM. ECG abnormalities often preceded the development of DCM by a significant period of time (3.7+/-2.6 years). Arrhythmias were common with 17/150 (11%) of the cohort being affected. Those with DCM were significantly more likely to have an arrhythmia with 16/64 (25%) of that group being affected (p < 0.01). The presence of VT was a poor prognostic indicator with 6/11 patients dying within 0.68+/-0.41 years. Conclusions: ECG abnormalities are strongly associated with DCM in patients with MD
and frequently precede cardiac dysfunction by several years. Arrhythmias are common and periodic ECG and Holter evaluations are warranted as they may predict early cardiac involvement.

 

USA - mulheres portadoras do gene da distrofinopatia apresentam risco de apresentar doenças cardíacas. Nesta pesquisa a avaliação do ecocardiograma foi feita após stress de exercício sendo comparado os resultados de 24 mulheres portadoras do gene defeituoso com os de 24 mulheres sem este gene. As portadoras de distrofinopatia apresentavam redução da função cardíaca em relação ao grupo controle e piora da função ao esforço, demonstrando a necessidade de acompanhamento da função cardíaca em mulheres que tenham o gene defeituoso da distrofina. O resumo em inglês pode ser lido abaixo:

 (J Am Soc Echocardiogr 2010) Exercise-Induced Left Ventricular Systolic Dysfunction in Women Heterozygous for Dystrophinopathy

RobertM.Weiss,Richard E. Kerber,MD, Jane K. Jones, CarrieM. Stephan, Christina J. Trout, Paul D. Lindower, Kimberly S. Staffey, Kevin P. Campbell, Katherine D. Mathews - USA

Background:Mutations in the X-linked gene encoding dystrophin cause skeletal and cardiac muscle diseases in men. Female ‘‘carriers’’ also can develop overt disease. The purpose of this study was to ascertain the prevalence of cardiac contractile abnormalities in dystrophinopathy carriers. Methods: Twenty-four dystrophinopathy heterozygotes and 24 normal women each underwent standard exercise stress echocardiography. Results: Heterozygotes demonstrated mildly lower left ventricular ejection fractions (LVEFs) at rest compared with controls (0.56 6 0.10 vs 0.62 6 0.07, P = .02). After exercise, the mean LVEF fell to 0.53 6 0.14 in heterozygotes but rose to 0.7360.07 in controls (P < .001). Twenty-one of 24 dystrophinopathy heterozygotes demonstrated >1% of the following: abnormal resting LVEF, abnormal LVEF response to exercise, or exercise-induced wall motion abnormality. Conclusions: Women heterozygous for dystrophinopathy demonstrate significant left ventricular systolic dysfunction, which is unmasked by exercise. This finding has mechanistic implications for both inherited and acquired cardiac disease states.

 

USA - os pesquisadores descrevem uma nova geração de oligonucleotídeos com capacidade 10 vezes maior de corrigir o defeito genético da distrofia muscular. Esta pesquisa foi realizada em camundongos com distrofia muscular. O resumo em inglês pode ser lido abaixo:

(Human Molecular Genetics, 2010) Site Directed Gene Repair of the Dystrophin Gene Mediated by PNA-ssODNs

Refik Kayali, Frederic Bury, McIver Ballard and Carmen Bertoni - USA

Permanent correction of gene defects is an appealing approach to the treatment of genetic disorders. The use of single-stranded oligodeoxynucleotides (ssODNs) has been demonstrated to induce single point mutations in the dystrophin gene and to restore dystrophin expression in skeletal muscle of models of Duchenne muscular dystrophy (DMD). Here we show that ssODNs made of peptide nucleic acids (PNA-ssODNs) can achieve gene repair frequencies more than 10 fold higher than those obtained using an older generation of targeting oligonucleotides. Correction was demonstrated in muscles cells isolated from mdx5cv mice and was stably inherited over time. Direct intramuscular injection of PNA-ssODNs targeting the mdx5cv mutation resulted in a significant increase in dystrophin positive fibers as compared to muscles that received the ssODNs designed to correct the dystrophin gene but made of unmodified bases. Correction was demonstrated at both the mRNA and the DNA levels using quantitative PCR and was confirmed by direct sequencing of amplification products. Analysis at the protein level demonstrated expression of full-length dystrophin in vitro as well as in vivo.

These results demonstrate that oligonucleotides promoting strand invasion in the DNA double helix can significantly enhance gene repair frequencies of the dystrophin gene. The use of PNA-ssODNs has important implications in terms of both efficacy and duration of the repair process in muscles and may have a role in advancing the treatment of DMD.

USA - nesta pesquisa um vetor viral contento o minigene da distrofina foi administrado em fetos de camundongos com distrofia muscular (a injeção foi realizada no abdome). Após 9 semanas de vida os animais foram estudados e se observou melhora das alterações patológicas no músculo diafragma evidenciando que o vetor viral se distribuiu pelo corpo levando o gene até o músculo respiratório.

Brasil - contrariando os resultados apresentados por outros pesquisadores (trabalho incluído há uma semana nesta página) o tratamento de longo prazo com L-arginina em camundongos com distrofia muscular não causou aumento da fibrose do coração.

USA - no quarto dia após o nascimento os animais receberam por via venosa uma injeção de um vetor viral contento o minigene da distrofina humana. Houve uma expressão do gene em músculos variados nos dois animais tratados mas houve uma resposta inflamatória ao tratamento. Algumas modificações do vetor viral precisam ser feitas e novos testes em cães realizados para demonstrar a viabilidade do método.

USA - a arginina já demonstrou benefícios em camundongos com distrofia muscular e frequentemente é utilizada como suplemento nutricional. Neste estudo realizado em camundongos com distrofia muscular e com suplementação por arginina os animais  apresentaram maior grau de fibrose muscular e cardíaca devido a ação de uma enzima argininase produzida por macrófagos. Para estudos pesquisadores a suplementação de arginina por longos períodos pode agravar o grau de lesão muscular.

USA - a distrofia óculo-faríngea ocorre por uma repetição de trinucleotídeos que acarreta agregação de uma proteína mutante no núcleo das células musculares; em células de camundongos com distrofia tipo óculo-faríngea e in vivo os autores estudaram os efeitos da cistamina. A droga causou uma menor agregação da proteína, reduz a fraqueza e as alterações patológicas dos camundongos. A droga inibe uma enzima, a transglutaminase 2 e deve ser estudada como uma provável opção terapêutica para a doença. O resumo em inglês pode ser lido abaixo:

(Science Translational Medicine, Jun 2010; 2: 34ra40) Cystamine Suppresses Polyalanine Toxicity in a Mouse Model of Oculopharyngeal Muscular Dystrophy

Janet E. Davies, Claudia Rose, Sovan Sarkar, and David C. Rubinsztein

Oculopharyngeal muscular dystrophy (OPMD) is caused by a trinucleotide repeat expansion mutation in the coding region of the gene encoding PABPN1 (polyadenylate-binding protein nuclear 1). Mutant PABPN1 with a polyalanine tract expansion forms aggregates within the nuclei of skeletal muscle fibers. There is currently no effective treatment. We have developed cell and mouse models of OPMD and have identified the aggregation of mutant PABPN1 and apoptosis as therapeutic targets. Here, we show that transglutaminase activity is increased in muscle from OPMD model mice. Elevated transglutaminase 2 expression enhances, whereas TG2 knockdown suppresses, the toxicity and aggregation of mutant PABPN1 in cells. Cystamine protects against the toxicity of mutant PABPN1 and exerts its effect via the inhibition of transglutaminase 2, as cystamine treatment is unable to further reduce the protective effect of transglutaminase 2 knockdown on mutant PABPN1 toxicity in cells. Cystamine also reduces the aggregation and toxicity of mutant PABPN1 in human cells. In a mouse model of OPMD, cystamine treatment reduced the elevated transglutaminase activity, attenuated muscle weakness, reduced aggregate load, and decreased apoptotic markers in muscle. Therefore, inhibitors of transglutaminase 2 should be considered as possible therapeutics for OPMD

 

 

França - a função respiratória é comprometida com a evolução da distrofia muscular de Duchenne, especialmente a partir da adolescência; nesta pesquisa; durante 7 anos dez meninos com Duchenne foram acompanhados dos 9,1+ 1 ano até os 16 + 1,4 anos. Os resultados demonstraram que a pressão inspiratória máxima apresentou redução desde o início do acompanhamento sendo que os parâmetros ventilatórios foram os melhores para acompanhamento nas fases mais avançadas da doença. O resumo em inglês pode ser lido abaixo:

(Pediatr Pulmonol. 2010; 45:552-559) Ventilatory parameters and maximal respiratory pressure changes with age in Duchenne muscular dystrophy patients

Jerome Gayraud, Michele Ramonatxo, François Rivier, MD, Véronique Humberclaude, Basil Petrof,  Stefan Matecki

The aim of this longitudinal study was to precise, in children with Duchenne muscular dystrophy, the respective functional interest of ventilatory parameters (Vital capacity, total lung capacity and forced expiratory volume in one second [FEV1]) in comparison to maximal inspiratory pressure (Pimax) during growth. In ten boys the mean age of 9.1 ± 1 years) to mean age of 16 ± 1.4 years followed over a period of 7 years, we found that: (1) ventilatory parameters expressed in percentage of predicted value, after a normal ascending phase, start to decrease between 11 and 12 years, (2) Pimax presented only a decreasing phase since the beginning of the study and thus was already at 67% of predicted value at 12 years while ventilatory parameters was still normal, (3) after 12 years the mean slopes of decrease per year of vital capacity and FEV1 were higher (10.7 and 10.4%) than that of Pimax (6.9%), (4) at 15 years mean values of vital capacity and FEV1 (53.3 and 49.5% of predicted values) was simlar to that of Pimax (48.3%). In conclusion, if at early stages of the disease, Pimax is a more reliable index of respiratory impaiment than ventilatory parameters, the follow-up of ventilatory parameters, when they start to decrease, is a better indicator of disease progression and, at advanced stages they provided same information about the functional impact of disease.

 

USA - baltimastat é uma potente droga inibidora das metaloproteases, que são enzimas extra-celulares, responsáveis pela degradação dos tecidos. O uso desta droga em camundongos com ditrofia muscular causou redução da necrose, menor infiltração de células inflamatórias e menor grau de lesão muscular. Houve um aumento da força dos animais tratados com a droga. O aumento das metaloproteases em distrofia muscular já tinha sido descrito; o uso da batimastat ou de outros inibidores das proteases pode ser um novo caminho nas pesquisas de tratamento para as distrofias musculares. O resumo em inglês pode ser lido abaixo:

 (Am J Pathol 2010, 177) Matrix Metalloproteinase Inhibitor Batimastat Alleviates Pathology and Improves Skeletal Muscle Function in Dystrophin-Deficient mdx Mice

Akhilesh Kumar, Shephali Bhatnagar AND Ashok Kumar - USA

Duchenne muscular dystrophy (DMD) , caused by mutations in the dystrophin gene, involves severe muscle degeneration, inflammation, fibrosis, and early death in afflicted boys. Matrix metalloproteinases (MMPs) are extracellular proteases that cause tissue degradation in several disease states. In this study, we tested the hypothesis that the expression levels of various MMPs are abnormally increased and that their inhibition will ameliorate muscle pathogenesis in animal models of DMD. Our results show that the transcript levels of several MMPs are significantly up-regulated, whereas tissue inhibitors of MMPs are down-regulated, in dystrophic muscle of mdx mice. Chronic administration of batimastat (BB-94) , a broad spectrum peptide inhibitor of MMPs, reduced necrosis, infiltration of macrophages, centronucleated fibers, and the expression of embryonic myosin heavy chain in skeletal muscle of mdx mice. Batimastat also reduced the expression of several inflammatory molecules and augmented the levels of sarcolemmal protein -dystroglycan and neuronal nitric oxide in mdx mice. In addition, muscle force production in isometric contraction was increased in batimastat-treated mdx mice compared with those treated with vehicle alone. Furthermore, inhibition of MMPs using batimastat reduced the activation of mitogen-activated protein kinases and activator protein-1 inmyofibers ofmdxmice. Our study provides the novel evidence that the expression of MMPs is atypically increased in DMD, that their inhibition ameliorates pathogenesis, and that batimastat could prove to be a significant candidate for DMD therapy.

 

USA - protandim é um suplemento nutricional de venda livre nos Estados Unidos e que tem atividade antioxidante. Os camundongos tratados com este suplemento apresentaram redução do stress oxidativo, redução da osteopontina, citocina inflamatória e melhora das alterações observadas na ressonância magnética. Não ocorreu melhora histológica e nem funcional. O suplemento foi bem tolerado pelos animais.

Brasil - aula sobre os cuidados ventilatórios nas doenças neuromusculares ministrada pela Dra. Ana Lúcia Langer, diretora clínica da ABDIM.

USA - miotonia é um sintoma precoce da distrofia miotônica do tipo 1 e que pode causar alterações motoras, de fala, de deglutição e dores musculares; 20 pacientes foram tratados com 150 mg de mexelitina, três vezes ao dia, comparando-se com placebo e num segundo estudo 200mg, três vezes ao dia. A mexelitina e uma droga antiarrítmica. Houve uma melhora da miotonia com 7 semanas de tratamento e  com efeitos colaterais discretos. A droga é efetiva e bem tolerada para tratamento da miotonia.

França - 9 pacientes com distrofia fácio-escápulo-umeral foram submetidos a treinamento estimulatório elétrico nos músculos acometidos em 5 sessões semanais de 20 minutos por 5 meses. Houve aumento da força muscular sem aumento da CK e da fadiga muscular. Este tratamento pode se constituir em uma alternativa segura e que pode aumentar a força muscular e a capacidade para atividades diárias. O resumo em inglês pode ser lido abaixo:

(Arch Phys Med Rehabil 2010;91:697-702) Neuromuscular electrical stimulation training: a safe and effective treatment for facioscapulohumeral muscular dystrophy patients

Colson SS, Benchortane M, Tanant V, Faghan J-P, Fournier-Mehouas M, Benaïm C, Desnuelle C, Sacconi S.


Objective: To investigate the feasibility, safety, and effectiveness of neuromuscular electrical stimulation (NMES) strength training in facioscapulohumeral muscular dystrophy (FSHD) patients.Design: Uncontrolled before-after trial. Setting: Neuromuscular disease center in a university hospital and a private-practice physical therapy office. Participants: FSHD patients (N 9; 3 women, 6 men; age 55.2 10.4y) clinically characterized by shoulder girdle and quadriceps femoris muscle weakness. Interventions: Patients underwent 5 months of strength training with NMES bilaterally applied to the deltoideus, trapezius transversalis, vastus lateralis, and vastus medialis muscles for five 20-minute sessions per week. Main Outcome Measures: Plasma creatine kinase (CK) activity; scores for pain and fatigue on visual analog scales (VAS), manual muscle testing (MMT), maximal voluntary isometric contraction (MVIC), 6-minute walking tests (6MWT), and self-reported changes in daily living activities. Results: NMES strength training was well tolerated (CK activity and pain and fatigue scores on VAS were not modified). Most of the muscle functions (shoulder flexion and extension and knee extension) assessed by MMT were significantly increased. MVIC of shoulder flexion and abduction and the 6MWT distance were also improved. Conclusions: In FSHD, NMES strength training appears to be safe with positive effects on muscle function, strength, and capacity for daily activities.

USA - no mais conceituado Congresso de Terapia Gênica e Celular serão apresentadas 50 pesquisas sobre o tema em distrofia muscular. A maioria dos estudos é experimental mas há interessantes abordagens que poderão se transformar futuramente em tratamentos. Há uma preocupação em vários trabalhos com a resposta imunológica que pode ocorrer com a expressão da distrofina. O organismo pode considerar a proteína como estranha e reagir prejudicando o resultado deste tratamento.

Inglaterra  - nesta conferência realizada em março foram apresentadas as mais recentes pesquisas em distrofia muscular com ênfase nos estudos com oligonucleotídeos, estudos experimentais e ensaios clínicos, a maioria já apresentada em outros congressos. Os resumos foram publicados em um suplemento da Revista Neuromuscular Disorders e podem ser lidos abaixo:

(Abstracts of the UK Neuromuscular Translational Research Conference Oxford, UK 25-26 March 2010)

Results of a systemic antisense study in Duchenne muscular dystrophy

Current progress with the systemic administration trial of AVI-4658, a novel Phosphorodiamidate Morpholino Oligomer
(PMO) skipping dystrophin exon 51 in Duchenne muscular dystrophy (DMD)

Multiexon skipping in Duchenne muscular dystrophy

Lentivirus-mediated stem cell therapy for Duchenne muscular dystrophy

Induction of dystrophin in Duchenne muscular dystrophy patients by antisense oligonucleotide AVI-4658 restores the dystrophin-associated glycoprotein complex

Evaluation of the truncated products of exon and multiple exon skipping in DMD therapy

Translation related clinical trials in duchenne muscular dystrophy (DMD) in the UK

Exploring emotional impact in a proof-of-principle single-blind, controlled, two-doses escalation intramuscular study of a morpholino splice-switching oligonucleotide (AVI-4658) trial to induce dystrophin restoration in children with Duchenne muscular dystrophy

A Novel Ankle foot orthoses/footwear combination to aid walking in Duchenne muscular dystrophy

Parental stress levels in parents of children with muscular dystrophy

UK NorthStar Neuromuscular Clinical Network (NSCN): National audit results in Duchenne muscular dystrophy (DMD) corticosteroid practice, vitamin D status and bone health

An audit of bone density and vertebral fractures during steroid treatment in Duchenne muscular dystrophy

Blocking calcium influx with streptomycin worsens myocardial pathology in the mdx mouse model of muscular dystrophy

Utrophin luciferase knock-in mouse model for in vivo assessment of drug efficacy in preclinical trials for utrophin upregulation

Rescu of severely affected dystrophin/utrophin deficient mice by morpholino-oligomer mediated exon skipping

Chronic long term administration of phosphorodiamidate morpholino oligomer profoundly ameliorates activity, muscle strength and phenotype in dystrophic mdx mice

Preventing dystroglycan phosphorylation as a route to therapy in DMD

Itália - os autores estudaram a associação de duas drogas conhecidas em camundongos com distrofia por deficiência em α- sarcoglicans; o ibuprofeno é um antinflamatório de uso bastante comum e o dinitrato de isosorbitol é uma medicação vasodilatadora usada no tratamento da angina do peito (uma droga doadora de óxido nítrico). A vantagem de estudar drogas conhecidas é a possibilidade de testes humanos já na fase 3, em pacientes com distrofia, dispensando duas etapas demoradas da pesquisa clínica. O tratamento combinado foi superior ao observado com cada droga isolada. Houve aumento da capacidade de regeneração, aumento das células precursoras, redução da inflamação e da necrose. Os autores concluem que o ibuprofeno e o dinitrato de isosorbitol tem efeito sinérgico e deveriam ser submetidos a estudos clínicos em pacientes com distrofia muscular

 (British Journal of Pharmacology, 2010) Co-administration of ibuprofen and nitric oxide is an effective experimental therapy for muscular dystrophy, with immediate applicability to humans

Clara Sciorati, Roberta Buono, Emanuele Azzoni, Silvana Casati, Pierangela Ciuffreda, Grazia D'Angelo, Dario Cattaneo, Silvia Brunelli, Emilio Clementi - Italy

Background and purpose: Current therapies for muscular dystrophy are based on corticosteroids. Significant side effects associated with these therapies have prompted several studies aimed at identifying possible alternative strategies. As inflammation and defects of nitric oxide (NO) generation are key pathogenic events in muscular dystrophies, we have studied the effects of combining the NO donor isosorbide dinitrate (ISDN) and the non-steroidal anti-inflammatory drug ibuprofen.

Experimental approach: α-Sarcoglycan null mice were treated for up to 8 months with ISDN (30 mg/kg) plus ibuprofen (50 mg/kg) administered daily in the diet. Effects of ISDN and ibuprofen alone were assessed in parallel. Drug effects on animal motility and muscle function, muscle damage, inflammatory infiltrates and cytokine levels, as well as muscle regeneration including assessment of endogenous stem cell pool, were measured at selected time points.

Key results: Combination of ibuprofen and ISDN stimulated regeneration capacity, of myogenic precursor cells, reduced muscle necrotic damage and inflammation. Muscle function in terms of free voluntary movement and resistance to exercise was maintained throughout the time window analysed. The effects of ISDN and ibuprofen administered separately were transient and significantly lower than those induced by their combination.

Conclusions and implications: Co-administration of NO and ibuprofen provided synergistic beneficial effects in a mouse model of muscular dystrophy, leading to an effective therapy. Our results open the possibility of immediate clinical testing of a combination of ISDN and ibuprofen in dystrophic patients, as both components are approved for use in humans, with a good safety profile.

Canadá - empresa francesa desenvolveu enzimas chamada de meganucleases capazes de corrigir defeitos genéticos. Usando plasmídeos como vetores contendo tais enzimaspesquisadores conseguiram corrigir in vitro o defeito genético de mioblastos. No camundongo com distrofia. Em camundongos com distrofia muscular o tratamento demonstrou também resultados. Como se trata de uma nova abordagem os autores precisam de mais 3 anos para testes em laboratório e animais para avaliar as possibilidades de sucesso em seres humanos.

Índia - 18 pacientes com Duchenne foram tratados com creatina 5g/dia por 8 semanas e comparados com 15 tratados com placebo (500 mg de vitamina C); os resultados demonstraram que a creatina é be tolerada mas os benefícios observados foram de curta duração, não se mantendo ao longo do tempo.

Canadá - o resumo dos estudos sobre a droga ataluren em Duchenne foram apresentado neste congresso; as pesquisas com esta droga foram suspensas no mês passado após a análise destes resultados. Apesar de não haver efeitos colaterais significativos todos os pacientes apresentaram perda de força ao longo das 48 semanas de estudo. O mais surpreendente foi que a dose maior da droga foi a que causou maior perda de força, maior até do que as crianças que não receberam tratamento.

Canadá - a empresa Prosensa apresentou neste congresso os resultados preliminares do tratamento de pacientes com Duchenne tratados com PRO051-02; o tratamento foi realizado em um número pequeno de pacientes e o objetivo maior era estudar a expressão da distrofina no músculo; a expressão desta proteína no músculo foi baixa de 15 a 20%, sem efeitos colaterais importantes. Não há resultado clínico que possa dizer que houve melhora clínica. Eles precisarão fazer novos estudos para acertar a dose a ser usada e avaliar também os resultados clínicos que são fundamentais.

Rio de Janeiro e França - receptores VLA-4 e VLA-5 e VLA-6 foram estudados nos línfócitos T de pacientes com Duchenne; os receptores de integrinas VLA-4 e VLA-5 estavam significantemente aumentados nos linfócitos T; estas integrinas podem contribuir para direcionar estas células para os músculos e agravar o dano e a fibrose dos músculos. O resumo em inglês pode ser lido abaixo:

(Journal of Neuroimmunology, 2010) Differential integrin expression by T lymphocytes: Potential role in DMD muscle damage

Fernanda Pinto-Mariz, Luciana Rodrigues Carvalho, Wallace de Mello, Alexandra de Queiroz Campos Araújo, Márcia Gonçalves Ribeiro, Maria do Carmo Soares Alves Cunha, Thomas Voit, Gillian Butler-Browne, Suse Dayse Silva-Barbosa, Wilson Savino - Brazil and France

The expression and function of integrin-type extracellular matrix receptors, VLA-4 and VLA-5, and laminin receptor VLA-6 on the surface of CD3+CD4+ and CD3+CD8+ defined T cell populations was evaluated in the blood of Duchenne muscular dystrophy (DMD) patients and healthy individuals. Both the number of CD4+ and CD8+ T cell subsets expressing VLA-4 or VLA-5 and the fibronectin-driven T cell migration was significantly higher in DMD patients. These data indicate that interactions of VLA-4 and/or VLA-5 with fibronectin may drive T lymphocytes to specific niches within muscle, contributing to tissue damage and fibrosis in DMD patients.

USA -  camundongos com distrofia muscular, com 11 semanas de vida, foram submetidos a exercícios físicos; os camundongos sedentários apresentaram maior espessura do músculo cardíaco e menor fibrose do que os camundongos que foram submetidos a exercícios físicos. O resumo em inglês pode ser lido abaixo:

(FASEB Meeting, 2010) The Effects of Exercise on Ventricular Wall Thickness and Fibrosis in Wild-Type and Dystrophin-Deficient Mice

Jeffrey H Plochocki and Jeffrey M Costas

Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ

Dystrophin is a cytoplasmic protein that connects muscle cells to the extracellular matrix. When absent, muscle degeneration and fibrosis occurs that resembles the histopathological presentation of Duchenne muscular dystrophy. In mice that lack dystrophin (Mdx mice), there is muscle degeneration and regeneration in the first few months of life, with fibrosis increasing after that. In this study, we evaluated the relationship between exercise and lateral ventricular wall thickness (LVT) in wild-type and Mdx mice aged 11 weeks. Degree of cardiac fibrosis was assessed using a trichrome stain. Sedentary Mdx mice exhibited significantly larger LVT than wild-type mice (P < 0.05). Exercise treated wild-type mice had larger LVT than sedentary wild-type mice on average, but this difference was not statistically significant. The LVT of sedentary Mdx mice was 28% larger than that of exercise treated Mdx mice (P < 0.05). Exercised treated Mdx mice were the only group that exhibited any noticeable fibrosis in the lateral aspect of the heart. Our findings suggest that exercise within the normal physiological range can accelerate degeneration and fibrosis of the lateral ventricular wall in Mdx mice.

USA -  estudos prévios já tinham demonstrado que o aumento da integrina {alpha}7 diminuia as alterações patológicas em modelos de distrofia muscular em camundongo. Nesta pesquisa os autores que o aumento concomitante das integrinas {alpha}7 e β1 é fundamental para o máximo benefício na redução das alterações degenerativas da distrofia muscular. O resumo em inglês pode ser lido abaixo:

(FASEB Meeting, 2010) Parallel increasing of {alpha}7 and β1 integrin prevents muscular dystrophy in mdx mice

Jianming Liu1,2 and Stephen J. Kaufman2

1 Cell & Tissue Biology, University of California San Francisco, San Francisco, CA
2 Cell & Developmental Biology, University of Illinois, Urbana, IL

Duchenne muscular dystrophy is a devastating muscle disease that is ultimately lethal. Without the dystrophin complex that normally connects myofibers actin cytoskeleton to the laminin in extracellular matrix, membrane integrity of muscle fibers is greatly compromised. One potential therapeutic treatment for muscular dystrophy is to augment the transmembrane linkages by increasing other laminin receptors such as integrins. We previously showed that transgenic expression of {alpha}7 chain of the integrin in skeletal muscle effectively alleviates the dystrophic pathologies and extends the lifespan of mdx/utrn–/– mice. However, expression of {alpha}7 chain alone in mdx mice provided little improvement of skeletal muscle health. We now found that in transgenic mice expressing high levels of {alpha}7 chain, relatively little {alpha}7 was targeted to the muscle membrane and thus mostly remained within myofibers, likely due to limiting amount of the endogenous integrin β1 protein. We then demonstrated that overexpress β1D integrin results in {alpha}7 chain increase in wild type mice and that commensurate increase of β1 chains in {alpha}7 transgenic mice promotes more functional heterodimers targeting to the sarcolemma. Likewise, increasing the amount of β1D integrin in {alpha}7-mdx transgenic mice also promotes localization of the {alpha}7β1 integrin to the sarcolemma and protects against muscle damages caused by the muscular dystrophy. Our results suggest that parallel increases of {alpha} and β integrin subunits are essential to achieve maximal beneficial effects of integrin based therapies for muscular dystrophy

São Paulo - a pesquisadora Mirella Barboni está realizando em seu doutorado no Instituto de Psicologia da USP uma pesquisa para estudar a visão de pacientes com distrofia muscular de Duchenne. Podem realizar este teste pacientes com Duchenne de qualquer idade, em tratamento ou não, e acompanhamento em qualquer instituição (ABDIM, Hospital das Clínicas, Hospital São Paulo, AACD, etc). A pesquisa realiza testes visuais não-invasivos e fornece avaliação oftalmológica realizada por uma médica oftalmologista. Os testes são feitos no Instituto de Psicologia da USP, na Cidade Universitária, e o tempo para sua realização é de, aproximadamente, 3 horas. Os participantes não são remunerados pela participação mas receberão reembolso das despesas de transporte e lanche. Os interessados em colaborar podem entrar em contato com a pesquisadora através do e-mail: mirellabarboni@usp.br.

Austrália - miostatina é uma proteína inibidora do desenvolvimento muscular; o uso de anticorpos anti-miostatina já demonstraram efeito benéfico em camundongos com distrofia muscular; nesta pesquisa o estudo foi feito no músculo diafragma, um dos mais afetados pela doença. O músculo diafragma dos animais jovens apresentaram melhra das alterações quando tratados com estes anticorpos. No entanto, os animais mais velhos não tiveram benefícios com a utilização destes anticorpos; os resultados podem indicar que esta terapia pode ser muito limitada para tratamento da distrofia muscular.

Israel e Japão - após o insucesso do ataluren para tratamento da distrofia muscular de Duchenne as atenções voltam-se novamente para os aminoglicosídeos, antibióticos que podem atuar na mutação sem sentido (mutação de ponto) da distrofia muscular. Nesta semana foram publicados duas pesquisas sobre o tema: na primeira os autores identificaram dois novos aminoglicosídeos com potencial de uso, mais efetivos e menos tóxicos; o segundo explora a possibilidade de uso da gentamincina por via transdérmica (através da pele). O resumo destas pesquisas pode ser lido abaixo:

(J. Biochem., Apr 2010; 147: 463 - 470) Transdermal delivery of a readthrough-inducing drug: a new approach of gentamicin administration for the treatment of nonsense mutation-mediated disorders

Masataka Shiozuka, Akira Wagatsuma, Tadafumi Kawamoto, Hiroyuki Sasaki, Kenichi Shimada, Yoshikazu Takahashi, Yoshiaki Nonomura, and Ryoichi Matsuda - Japan

To induce the readthrough of premature termination codons, aminoglycoside antibiotics such as gentamicin have attracted interest as potential therapeutic agents for diseases caused by nonsense mutations. The transdermal delivery of gentamicin is considered unfeasible because of its low permeability through the dermis. However, if the skin permeability of gentamicin could be improved, it would allow topical application without the need for systemic delivery. In this report, we demonstrated that the skin permeability of gentamicin increased with the use of a thioglycolate-based depilatory agent. After transdermal administration, the readthrough activity in skeletal muscle, as determined using a lacZ/luc reporter system, was found to be equivalent to systemic administration when measured in transgenic mice. Transdermally applied gentamicin was detected by liquid chromatography-tandem mass spectrometry in the muscles and sera of mice only after depilatory agent-treatment. In addition, expansion of the intercellular gaps in the basal and prickle-cell layers was observed by electron microscopy only in the depilatory agent-treated mice. Depilatory agent-treatment may be useful for the topical delivery of readthough-inducing drugs for the rescue of nonsense mutation-mediated genetic disorders. This finding may also be applicable for the transdermal delivery of other pharmacologically active molecules.
 

(Bioorganic & Medicinal Chemistry,2010) Repairing faulty genes by aminoglycosides: Development of new derivatives of geneticin (G418) with enhanced suppression of diseases-causing nonsense mutations

Igor Nudelamn, Dana Glikin, Boris Smolkin, Mariana Hainrichson, Valery Belakhov and Timor Baasov - Israel

New pseudo-di- and pseudo-trisaccharide derivatives of the aminoglycoside drug G418 were designed, synthesized and their ability to readthrough nonsense mutations was examined in both in vitro and ex vivo systems, along with the toxicity tests. Two novel lead structures, NB74 and NB84, exhibiting significantly reduced cell toxicity and superior readthrough efficiency than those of gentamicin, were discovered. The superiority of new leads was demonstrated in six different nonsense DNA-constructs underling the genetic diseases cystic fibrosis, Duchenne muscular dystrophy, Usher syndrome and Hurler syndrome.

 

Santo André - a palestra será ministrada pela Dra. Irina Kerkis, pesquisadora do Instituto Butantan  e será realizada no dia 15/04/2010 na Faculdade de Medicina da Fundação do ABC (Avenida Príncipe de Gales, 821, Santo André, SP) no anfiteatro 6 (Goffi) às 12hs. A palestra organizada pelo Departamento de Morfologia e Fisiologia será aberta ao público. A Dra Irina tem vasta experiência com células tronco, inclusive com experimentos em animais com distrofia muscular. Apesar da palestra não ser específica sobre o uso em distrofia muscular é uma boa oportunidade para ouvir quem realmente tem conhecimento e experiência em células-tronco.

USA - a droga tadalafil, comercializada com o nome Cialis e utilizada para tratamento de disfunção erétil será testada em pacientes com distrofia muscular de Becker. O objetivo é aumentar a quantidade de óxido nítrico importante vasodilatador e com papel importante na proteção da célula muscular.

Israel - o acetato glatiramer é uma droga liberada para uso humano no tratamento da esclerose múltipla; além de atuar na regeneração da mielina a droga é imunomoduladora. Nesta pesquisa a droga foi utilizada em camundongos deficientes em merosina. Houve redução da fibrose e aumento da atividade e da força muscular. O resumo em inglês pode ser lido abaixo:

(Neuromuscular Disorders, 2010) Improved muscle strength and mobility in the dy2J/dy2J mouse with merosin deficient congenital muscular dystrophy treated with Glatiramer acetate

Oshrat Dadush, Shlomit Aga-Mizrachi, Keren Ettinger, Rinat Tabakman, Moran Elbaz, Yakov Fellig, Nurit Yanay, Yoram Nevo - Israel

The therapeutic effect of Glatiramer acetate, an immune modulating agent, was evaluated in the dy2J/dy2J mouse with merosin deficient congenital muscular dystrophy, which is a milder variant of the dy/dy mouse. The treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter and in motor performance quantified by video detection software. Glatiramer acetate treatment was associated with significantly increased expression of regeneration transcription factors MyoD and myogenin, and attenuation of the fibrosis markers vimentin and fibronectin. No effective treatment is currently available in congenital muscular dystrophy and Glatiramer acetate may present a new potential treatment for this disorder.

Brasil - nesta segunda feira começa a vacinação para as pessoas com maior predisposição a gripe e suas complicações; neste grupo se incluem os portadores de doenças neuromusculares como as distrofias. Boatos infundados tem sido divulgados quanto a segurança da vacinação. Os boatos são inteiramente falsos e não há nenhuma dúvida quando a qualidade e segurança da vacina. A recomendação é que todos tomem a vacina.

Itália -  em estudos prévios os autores já tinham demonstrado os benefícios experimentais dos inibidores do proteasoma como o mg-132; nesta pesquisa eles usam a droga bortezomib (velcade) liberada para tratamento do mieloma múltiplo. Em camundongos a droga restaurou a distrofina e melhorou as alterações musculares presentes na doença; utilizado em cultura de células de pacientes com Duchenne e Becker houve aumento da expressão das próteínas da membrana como a distrofina e sarcoglicans. É uma droga potencialmente útil para tratamento da doença e cujo potencial deveria ser explorado em estudos clínicos. O resumo em inglês da pesquisa pode ser lido abaixo:

(Am. J. Pathol. 2010,176(4):1863-1877)Therapeutic Potential of Proteasome Inhibition in Duchenne and Becker Muscular Dystrophies
Elisabetta Gazzerro, Stefania Assereto, Andrea Bonetto, Federica Sotgia, Sonia Scarfì, Angela Pistorio, Gloria Bonuccelli, Michele Cilli, Claudio Bruno, Federico Zara, Michael P. Lisanti, and Carlo Minetti - Italy

Duchenne muscular dystrophy (DMD) and its milder allelic variant, Becker muscular dystrophy (BMD), result from mutations of the dystrophin gene and lead to progressive muscle deterioration. Enhanced activation of proteasomal degradation underlies critical steps in the pathogenesis of the DMD/BMD dystrophic process. Previously, we demonstrated that treatment with the proteasome inhibitor MG-132 rescues the cell membrane localization of dystrophin and the dystrophin glycoprotein complex in mdx mice, a natural genetic mouse model of DMD. The current work aims to thoroughly define the therapeutic potential in dystrophinopathies of Velcade, a drug that selectively blocks the ubiquitin-proteasome pathway. Velcade is particularly intriguing since it has been approved for the treatment of multiple myeloma. Therefore, its side effects in humans have been explored. Velcade effects were analyzed through two independent methodological approaches. First, we administered the drug systemically in mdx mice over a 2-week period. In this system, Velcade restores the membrane expression of dystrophin and dystrophin glycoprotein complex members and improves the dystrophic phenotype. In a second approach, we treated with the compound explants from muscle biopsies of DMD or BMD patients. We show that the inhibition of the proteasome pathway up-regulates dystrophin, {alpha}-sarcoglycan, and {beta}-dystroglycan protein levels in explants from BMD patients, whereas it increases the proteins of the dystrophin glycoprotein complex in DMD cases.
 

 

USA - poloxamer, é um vedante da membrana celular, algo como um cimento que protege as células lesadas. Ele tem sido estudado há quase 10 anos no tratamento da distrofia muscular; nesta pesquisa, administrado por 2 meses causou melhora das alterações do músculo cardíaco e redução dos níveis sanguíneos dos marcadores de lesão cardíaca. Os autores omitem o que ocorreu com os músculos esqueléticos; estudos prévios em camundongos com distrofia muscular mostraram que a droga não teve efeito na força muscular destes animais.

Espanha - melatonina é um hormônio produzido pelo organismo e que atua na regulação do sono e que apresenta propriedades anti-inflamatórias. No presente estudo 10 pacientes com Duchenne, em média com 13 anos, que foram tratados com melatonina (60mg a noite e 10 mg pela manhã). Os pesquisadores observaram uma significativa redução das citoninas inflamatória no sangue dos pacientes além da redução do stress oxidativo. O seguimento foi realizado por 9 meses e houve também redução das enzimas no sangue (CK, TGO, TGP, DHL). O estudo sugere que a melatonina pode contribuir para redução da degeneração dos músculos em Duchenne.

Itália - inibidores da desacetilação da histona já demonstraram efeitos positivos em camundongos com distrofia muscular; neste estudo a avaliação foi feita sobre as arritmias em repouso, no stress e induzidas por drogas. Redução significativa das arritmias foi observada nos animais tratados; sugere-se que este efeito possa se relacionar com a ação da droga sobre canais de sódio. Esta classe de drogas necessita ser melhor estudada em modelos de distrofia muscular. O resumo em inglês pode ser lido abaixo:

(Cardiovasc Res, Mar 2010) The histone deacetylase inhibitor suberoylanilide hydroxamic acid reduces cardiac arrhythmias in dystrophic mice

Claudia Colussi, Roberta Berni, Jessica Rosati, Stefania Straino, Serena Vitale, Francesco Spallotta, Silvana Baruffi, Leonardo Bocchi, Francesca Delucchi, Stefano Rossi, Monia Savi, Dante Rotili, Federico Quaini, Emilio Macchi, Donatella Stilli, Ezio Musso, Antonello Mai, Carlo Gaetano, and Maurizio C. Capogrossi - Italy

Aims The effect of histone deacetylase inhibitors on dystrophic heart function is not established. To investigate this aspect, dystrophic mdx mice and wild-type (WT) animals were treated 90 days either with suberoylanilide hydroxamic acid (SAHA, 5 mg/kg/day) or with an equivalent amount of vehicle.

Methods and results The following parameters were evaluated: (i) number of ventricular arrhythmias in resting and stress conditions (restraint test) or after aconitine administration; (ii) cardiac excitability, conduction velocity, and refractoriness; (iii) expression and distribution of connexins (Cxs) and Nav1.5 sodium channel. Ventricular arrhythmias were negligible in all resting animals. During restraint, however, an increase in the number of arrhythmias was detected in vehicle-treated mdx mice (mdx-V) when compared with SAHA-treated mdx (mdx-SAHA) mice or normal control (WT-V). Interestingly, aconitine, a sodium channel pharmacologic opener, induced ventricular arrhythmias in 83% of WT-V mice, 11% of mdx-V, and in 57% of mdx-SAHA. Epicardial multiple lead recording revealed a prolongation of the QRS complex in mdx-V mice in comparison to WT-V and WT-SAHA mice, paralleled by a significant reduction in impulse propagation velocity. These alterations were efficiently counteracted by SAHA. Molecular analyses revealed that in mdx mice, SAHA determined Cx remodelling of Cx40, Cx37 and Cx32, whereas expression levels of Cx43 and Cx45 were unaltered. Remarkably, Cx43 lateralization observed in mdx control animals was reversed by SAHA treatment which also re-induced Nav1.5 expression.

Conclusion SAHA attenuates arrhythmias in mdx mice by a mechanism in which Cx remodelling and sodium channel re-expression could play an important role.

 

USA - os autores fazem uma revisão do uso de corticóides na prática clínica diária no período de 1991 a 2005 para tratamento de Duchenne e Becker nos Estados Unidos. O uso de corticoide aumentou nos últimos anos, chegando a 44% do total de pacientes. O uso se iniciou em média aos 6,9 anos. Os motivos para suspensão da medicação foram: ganho de peso, alterações comportamentais, parada da deambulação com o uso de cadeira de rodas continuadamente.  O resumo em inglês pode ser lido abaixo:

(Journal of Child Neurology, 2010) Use of Corticosteroids in a Population-Based Cohort of Boys With Duchenne and Becker Muscular Dystrophy

Dennis J. Matthews, Katherine A. James, Lisa A. Miller,  Shree Pandya, Kimberly A. Campbell, Emma Ciafaloni, Katherine D. Mathews, Timothy M. Miller, Christopher Cunniff, MD, F. John Meaney, Charlotte M. Druschel, Paul A. Romitti, P, and Deborah J. Fox - USA.

The use of corticosteroids for treatment of Duchenne and Becker  muscular dystrophy in clinical practice from 1991 through 2005 was reviewed in a large population-based cohort (MD STARnet) of boys in 4 regional sites and 6 clinics of the United States. Corticosteroid use increased from 20% (11 of 56 individuals) in 1991 to 44% (93 of 218 individuals) in 2005. Average use varied by site and ranged from 15% to 49%. The median age of corticosteroid initiation was 6.9 years (range, 3.7-17.4 years). Dosage and growth information was available for 102 participants and showed a median dose as 0.729 mg/kg for prednisone and 0.831 mg/kg for deflazacort. T. The most common reasons that corticosteroids were discontinued included weight gain, behavioral side effects, and loss of ambulation, resulting in full-time wheelchair use. Substantial variations in clinical practice were identified among study sites.

 

USA - todos os estudos clínicos com a droga ataluren na distrofia muscular de Duchenne foram suspensos; pacientes que estavam recebendo a droga após os estudos prévios não receberão mais o medicamento até a conclusão final dos resultados. Novas informações serão divulgadas nos próximos dias.

USA - hoje as empresas PTCTherapeutics and Genzyme divulgaram os primeiros resultados da fase 2B com a droga ataluren (PTC-124). A droga seria  útil na mutação sem sentido (mutação de ponto) que está presente em menos de 15% dos pacientes. O objetivo primário era avaliar o efeito da droga sobre a capacidade de caminhar 6 minutos; não houve diferença entre os tratados e os controles. A droga foi bem tolerada, sem efeitos colaterais significativos e sem abandono do tratamento. As outras avaliações laboratoriais, biópsias, etc serão divulgadas nos próximos meses.

Canadá - neste ano o congresso realizar-se-á em Toronto e haverá a apresentação de 21 trabalhos relacionados com distrofia muscular e cujos resumos estão abaixo com uma pequena explicação sobre cada um deles:

1) Preliminary Results with AVI-4658 of Dystrophin Expression, Safety and Pharmacokinetics from the First Systemic Administration Study in Boys with Duchene Muscular Dystrophy (DMD), with a Phosphorodiamidate Morpholino Oligomer (PMO) to Skip Exon 51

 Francesco Muntoni, London, United Kingdom, Kate Bushby, Newcastle upon Tyne, United Kingdom, Cirak Sebahattin, London, United Kingdom, Michela Guglieri, Newcastle upon Tyne, United Kingdom, Shirley Leow, Stephen B. Shrewsbury, Bothell, WA

OBJECTIVE: We have previously identified a PMO to skip exon 51 in DMD patients, restore the reading frame and enable dystrophin expression. The current study, on repeated IV treatment to select an effective, tolerated dose, should complete in February 2010. BACKGROUND: DMD is the commonest inherited muscular dystrophy, affecting 1 in every 3,500 boys. DMD boys present with leg weakness by age 5, wheelchair confinement by age 10-12; respiratory insufficiency requiring mechanical ventilation by late teens, and cardiomyopathy, placing a huge burden on patient and parents/caregivers. Out of frame deletions abolishing the production of the muscle protein dystrophin are the commonest mutations. DESIGN/METHODS: Open label, dose escalation study in ambulant DMD boys aged 5-15 years with relevant deletions, of 12 weekly administrations of AVI-4658; muscle biopsy to assess dystrophin expression at baseline and 14 weeks. Clinical parameters are followed for 26 weeks, consisting of safety (adverse events, physical examinations, laboratory tests), skeletal muscle, pulmonary and cardiac function, and pharmacokinetics at 1st, 6th and 12th doses. A DSMB guides dose escalation decisions (across the doses 0.5, 1.0, 2.0, 4.0, 10.0 and 20.0 mg/kg). RESULTS: Cohorts 1, 2, 3 and 4 completed 12 weeks of dosing (October 2009). Cohort 1 has completed follow up to 26 weeks. Cohorts 5 and 6 are proceeding with dosing. No drug related SAEs or severe drug related AEs have been reported so far. To date, maximum cumulative PMO dose approaches 3,000mg. Preliminary analysis of the exon skipping, RNA and dystrophin protein expression will be presented and safety data updated. CONCLUSIONS/RELEVANCE: The first PMO for DMD has been well tolerated at all doses to date. Preliminary data is expected to show dystrophin expression at one or more doses and will allow dose selection for confirmatory clinical studies and extended (compassionate) use Supported by: Medical Research Council, UK and AVI Biopharma.

Pesquisa que descreverá os resultados do uso de oligonucleotídeos para pacientes com Duchenne e mutação do exon 51. Estudo ainda em andamento.

2) Preclinical Safety of AVI-4658, a Phosphorodiamidate Morpholino Oligomer (PMO) Being Developed To Skip Exon 51 in Duchenne Muscular Dystrophy

 Peter Sazani, Stephen Shrewsbury, Bothell, WA

OBJECTIVE: The current studies were designed to assess the safety of AVI-4658 (and PMO in general). BACKGROUND: AVI-4658 is a PMO that skips dystrophin exon 51, restores the reading frame and enable dystrophin expression in selected DMD boys, proven by our recent single IM dose study in the UK. To enable clinical trials in the US, three 12-week GLP studies in animals were performed. Published data suggests the older phosphorothioate antisense oligonucleotides have dose limiting toxicities. DESIGN/METHODS: (1) mdx mice were dosed IV with 0, 12, 120 or 960mg/kg (the maximum feasible dose (MFD)), or subcutaneously at 960mg/kg; wild type C57 mice at 0 and 960 mg/kg (i.e., 7 groups) with AVI-4658. (2) A second identical study with AVI-4225, the PMO to skip exon 23 of in the dystrophic mouse and restore dystrophin, was also performed. (3) Cynomolgus monkeys were dosed IV with 0, 5, 40 or 320mg/kg (MFD) and 320mg/kg subcutaneously. A 28 day recovery period was included in all studies. RESULTS: In mice, both AVI-4658 and AVI-4225 were well tolerated at doses including 960 mg/kg/injection, with no adverse effects. Findings were generally limited to the kidney, and were generally reversible, as shown in the 28 day recovery groups. No evidence of kidney function change was detected. In cynomolgus monkeys, AVI-4658 was also well tolerated at all doses including 320 mg/kg/injection, with no adverse effects. Findings were similar to those seen in the mouse studies. CONCLUSIONS/RELEVANCE: AVI-4658, the first PMO for DMD, was extremely well tolerated at all doses in dystrophic mice, normal mice and primates. In addition, AVI-4225, which restores dystrophin in mdx mice, also led to no adverse effects. Based on this preclinical package, and encouraging safety and dystrophin expression results from a concurrent UK clinical study, US clinical studies are anticipated.

Pesquisa que descreve o uso de oligonucleotídeos em estudos experimentais para tratamento da mutação do exon 51 em portadores de distrofia muscular de Duchenne.

3) A Phase I/IIa Systemic Study on Antisense Oligonucleotide Compound PRO051 in Patients with Duchenne Muscular Dystrophy

 Nathalie M. Goemans, Leuven, Belgium, Mar Tulinius, Gothenburg, Sweden, Gunnar Buyse, Leuven, Belgium, Sjef J. de Kimpe, Judith C. van Deutekom, Leiden, The Netherlands

OBJECTIVE: In this phase I/IIa open label study we evaluated the systemic delivery of the antisense oligonucleotide compound PRO051 in Duchenne Muscular Dystrophy (DMD) patients. BACKGROUND: DMD patients suffer from progressive muscle degeneration due to mutations in the DMD gene and the resulting absence of dystrophin at the muscle fiber membrane. PRO051, an antisense oligonucleotide compound, induces specific exon 51 skipping during pre-mRNA splicing, and can induce novel dystrophin expression in a subpopulation of DMD patients (Van Deutekom N Eng J Med 2007;357(26):2719-2722). DESIGN/METHODS: Twelve DMD patients received 5 weekly subcutaneous injections. Four dosing cohorts were applied (0.5 mg/kg, 2 mg/kg, 4 mg/kg, 6 mg/kg), three patients each. Muscle biopsies were taken at baseline for patients in cohort 1, and at two and seven weeks after the last administration for all patients. Adverse events were recorded and safety assessments (laboratory analysis and ECG) were performed at regular intervals. RESULTS: PRO051 induced specific exon 51 skipping in cohorts 2, 3 and 4, and novel dystrophin expression in a dose related manner in all cohorts. The treatment was well tolerated, none of the patients discontinued. A review of the safety data revealed no clinically significant changes in laboratory values and ECG. Antibodies against dystrophin were not detected. CONCLUSIONS/RELEVANCE: This is the first study showing successful systemic administration of an antisense oligonucleotide compound in DMD patients. An extension study is ongoing to collect at least 6 months safety data in all 12 patients at 6 mg/kg. A phase 3 study is in preparation. Supported by: Prosensa Therapeutics BV, the Netherlands.

Pesquisa que mostra os resultados iniciais do uso de oligonulceotídeos para tratamento da mutação do exon 51 em pacientes com Duchenne, demonstrando segurança do procedimento, sem efeitos colaterais.

4)  Gentamicin Treatment of Duchenne Muscular Dystrophy Reinforces the Potential for Mutation Suppression Therapy

Vinod Malik, Louise R. Rodino-Klapac, Laurence Viollet, OH, Cheryl Wall, Wendy King, Roula Al-Dahhak, Sarah Lewis, Christopher J. Shilling, Janaiah Kota, Columbus, OH, John Hayes, Forest Grove, OR, John D. Mahan, Katherine J. Campbell, Columbus, OH, Brenda Banwell, Toronto, ON, Canada, Majed Dasouki, Victoria Watts, Kansas City, KS , Kumaraswamy Sivakumar, Ricardo Bien-Willner, Scottsdale, AZ, Kevin M. Flanigan, Zarife Sahenk, Columbus, OH, Richard J. Barohn, Kansas City, KS, Christopher M. Walker, Jerry R. Mendell, Columbus, OH

OBJECTIVE: Establish if the biopotency of gentamicin demonstrated in the mdx mouse can be confirmed in a clinical setting and if so, how could it be administered considering that readthrough would be an ongoing requirement. Address the percent increase in dystrophin expression required to provide clinically meaningful outcomes, and the potential immunogenicity of newly expressed dystrophin epitopes following treatment. BACKGROUND: Mutation suppression, also referred to as readthrough of stop codons, to restore the dystrophin gene is undergoing clinical trials in Duchenne muscular dystrophy (DMD). DESIGN/METHODS: Duchenne muscular dystrophy (DMD) subjects included: 1) Cohort 1 (n = 10) stop codon patients and Cohort 2 (n=8) frameshift controls receiving 14-days of gentamicin (7.5 mg/day). 2) Cohort 3 (n =12) and Cohort 4 (n=4) received an unprecedented six month delivery of weekly or twice-weekly gentamicin permitting an accumulating dystrophin pool to reach potential therapeutic levels. Readthrough was assessed in pre-and post-treatment biopsies and by clinical outcomes. RESULTS: In the 14-day biopotency study serum CK dropped by 50%, not seen in frameshift DMD controls. After 6-months of gentamicin, dystrophin levels significantly increased (p = 0.027) reaching levels 13% to 15% of normal accompanied by a drop in serum CK, stabilization of strength by manual muscle testing and a slight increase in forced vital capacity without adverse events. Stable transcripts that escaped nonsense mediated decay predicted the greatest increase of dystrophin following gentamicin. The efficiency of readthrough was not affected by either the stop codon or the fourth nucleotide surrounding the stop. Novel immunogenic epitopes were found in post-treatment biopsies by antigen specific IFN-g ELISpots. CONCLUSIONS/RELEVANCE: The results support on-going efforts to achieve drug-induced mutation suppression of stop codons. Immunogenic epitopes resulting from readthrough emphasize the importance of monitoring T cell immunity during clinical gene manipulation trials including mutation suppression, exon skipping and gene therapy. Supported by: NIH, NINDS, MDA, Jesse's Journey, The University of Kansas Medical Center GCRC Grant

Pesquisa que descreve os resultados do uso da gentamicina para tratamento da mutação sem sentido (mutação de ponto) em Duchenne. Houve uma redução da CK no sangue, aumento discreto da expressão da distrofina e discreto aumento da capacidade pulmonar.

5) Transient Expression of a Therapeutic Dystrophin Transgene in Duchenne Muscular Dystrophy Revealed by T Cell Mediated Immunity

 Jerry Mendell, Katherine Campbell, Louise Rodino-Klapac, Zarife Sahenk, Christopher Shilling, Sarah Lewis, Columbus, OH, Dawn Bowles, Steven Gray, Chengwen Li, Chapel Hill, NC, Gloria Galloway, New Albany, OH, Vinod Malik, Brian Coley, Reed Clark, Columbus, OH, Juan Li, Xiao Xiao , Jade Samulski, Scott McPhee, R. Samulski, Chapel Hill, NC, Christopher Walker, Columbus, OH

OBJECTIVE: Describe the immune response following gene therapy for Duchenne muscular dystrophy (DMD) using adeno-associated virus (AAV) to transfer the mini-dystrophin gene. BACKGROUND: Gene therapy for DMD is a potentially promising means of gene replacement to restore dystrophin expression. This study reports the first clinical trial of viral mediated gene transfer in DMD. DESIGN/METHODS: Six DMD subjects were enrolled in a double-blind gene transfer study to the biceps muscle. Four were receiving glucocorticoid therapy at the time of gene transfer. The mini-dystrophin transgene used in this study encoded the actin binding domain, 5 rod spectrin repeats (R1, R2, R22, R23, and R24), 3 hinge domains (H1, H3 and H4), and the cysteine-rich domain. Expression was under control of the human cytomegalovirus immediate early promoter. Vector genomes were packaged in a hybrid AAV 2 capsid with 6 amino acid substitutions designed to minimize recognition by serum neutralizing antibodies. RESULTS: Four of six subjects with frame-shifting deletions in the DMD gene had detectable T cell responses to mini-dystrophin. Most of the targeted epitopes were non-self, located in sequences unique to the therapeutic dystrophin protein. However in at least one instance the dystrophin-specific T cells were present at low frequency before vector treatment and expanded rapidly after mini-dystrophin expression. The target of this unexpected memory T cell response was a self-epitope expressed from the defective dystrophin gene in revertant muscle fibers. CONCLUSIONS/RELEVANCE: This study illustrates the potential for a host response to foreign transgene products that are caused by large deletions or frame-shifting mutations. Recall of auto-reactive T cells has important clinical significance beyond gene therapy for DMD. Similar cell-mediated immune responses could be elicited by any strategy that increases expression of functional dystrophin in subjects with DMD and should be considered in the design and monitoring of experimental therapies for this disease. Supported by: The MDA and Jesse's Journey.

Pesquisa que descreve a reação imunológica que ocorre com a terapia gênica na distrofia muscular de Duchenne; crianças tratadas com vetor viral e o mini-gene da distrofina apresentaram linfócitos contra o gene da distrofina.

6)  Initial Efficacy and Safety Evaluation in Cynomolgus Monkeys of AVI-5038, a Peptide Conjugated Phosphorodiamidate Morpholino Oligomer (PPMO) Being Developed To Skip Exon 50 in Duchenne Muscular Dystrophy

 Peter Sazani, Stephen Shrewsbury, Bothell, WA

OBJECTIVE: To evaluate the efficacy of AVI-5038 at inducing skipping of dystrophin exon 50, as determined by RT-PCR, and also perform an initial toxicology assessment. BACKGROUND: AVI-5038 is a PPMO that induces dystrophin exon 50, and is designed to restore the reading frame and enable dystrophin expression in DMD patients. DESIGN/METHODS: Cynomolgus monkeys were dosed IV with 0, 3, or 9 mg/kg with AVI-5038, once weekly for 4 weeks. Following a 21 day recovery period, animals were sacrificed and a toxicological evaluation was performed. Selected muscle tissues were also evaluated by RT-PCR for evidence of skipping of dystrophin exon 50. RESULTS: AVI-5038 was well tolerated, with no adverse effects detected at doses up to 9 mg/kg. Toxicological findings were generally limited to the kidney, and included basophilic granules and instances of tubular degeneration / regeneration that was dose dependant. No clear evidence of kidney function change was detected, as shown by clinical chemistry and urinalysis evaluations. Significant levels of exon skipping were detected by RT-PCR in all major muscle groups evaluated, including diaphragm, heart, and quadriceps, at 9 mg/kg. CONCLUSIONS/RELEVANCE: AVI-5038, the first PPMO for DMD, was extremely well tolerated at all tested doses in primates. In addition, the safety data indicate that higher doses could be used to produce greater efficacy. Exon skipping was induced by the PPMO in healthy primate's muscles following systemic administration.

Estudo em macacos com o uso de oligonucleotídeos para tratamento da mutação do exon 51 na distrofia muscular de Duchenne.

7)  Outcome Measures Validation Study for Mesoangioblasts Transplantation in Children Affected by Duchenne Muscular Dystrophy

 Serena Bonfiglio, Alberto Lerario, Andrea Tettamanti, Sarah Marktel, Sara Napolitano, Stefano Previtali, Marina Scarlato, Maria Grazia Natali Sora, Nereo Bresolin, Giancarlo Comi, Roberto Gatti, Fabio Ciceri, Giulio Cossu, Yvan Torrente, Milano, Italy

OBJECTIVE: The aim of this study is to establish a reliable tool of reproducible assessment of muscle strength in children affected by Duchenne muscular dystrophy (DMD) which will be selected for mesoangioblasts transplantation. BACKGROUND: We have developed a potential treatment for DMD based on infusion of cells (mesoangioblasts) from a healthy donor capable. The results of the current functional study will hopefully establish reliable qualitative and quantitative tool to assess results of a future cell therapy clinical trial with mesoangioblasts. DESIGN/METHODS: This is a single centre, prospective, non-randomised, study of validation of outcome measures on 30 ambulant patients aged 5 to 12 years old affected by DMD including a cohort of 15 healthy aged matched males. We perform two days evaluation each three month for one year. During each assessment the following outcome measures are applied to DMD subjects: North Star Scale and 6 minute walking test during the first day; quantitative assessment using the Kin Com 125 machine during the second day. The controls subjects will perform quantitative assessment twice in a year. Twice during this evaluation year patients perform spyrometry, cardiac assessment and lower limb MRI. RESULTS: We divided the patients into 3 subgroups of age (5-7 years, 8-9 years, 10-12 years). The results of this preliminary part of the study show specific correlation between functional and quantitative tests in stronger children. Kin Com measurements correlate appropriately with functional tests for 10-12 years old DMD boys, while show a major variability in muscle strength for 8-9 years old DMD boys. The comparison with healthy subjects showed a difference of muscle strength that increases with age. CONCLUSIONS/RELEVANCE: This preliminary study demonstrates that our assessment may represent a useful tool to monitor the progress of DMD in ambulant children to determine the pre-transplantation story of the children who will be later treated with mesoangioblasts.

Pesquisa preliminar demonstrando como será realizada a avaliação dos pacientes que participarão do estudo clínico com o uso de mesangioblastos no tratamento da distrofia muscular de Duchenne.

8) The 6-Minute Walk Test in Duchenne Muscular Dystrophy: Longitudinal Observations

 Craig McDonald, Erik Henricson, Sacramento, CA, Richard Abresch, Davis, CA, Jay Han, Alina Nicorici, Erica Goude, Sacramento, CA, Gary Elfring, Allen Reha, Samit Hirawat, Langdon Miller, S. Plainfield, NJ

OBJECTIVE: To develop the six-minute walk test (6MWT) as a clinically-valid outcome measure for ambulatory boys with Duchenne muscular dystrophy (DMD). BACKGROUND: We evaluated longitudinal changes in the ambulation of boys with (DMD) and age-matched controls, ages 4-13 years, using a 6MWT modified for use in DMD therapeutic trials. DESIGN/METHODS: We tested 18 boys with confirmed DMD and 22 healthy boys, ages 4-13 years using a our previously reported 6MWT methodology. Boys were tested at baseline and after 1 year. RESULTS: The median [range] test-retest interval was 58 [35-84] weeks in boys with DMD and 66 [51-114] weeks in healthy boys. At baseline, 13/18 (72%) boys with DMD were using corticosteroids. The groups were similar in age, height, and weight. Mean six-minute walk distance (6MWD) declined (p=0.054) in boys with DMD (mean [SD] change = -54 [100] m) but increased in healthy boys (mean [SD] change = 16 [54] m). Mean stride length decreased in boys with DMD (mean [SD] change = -0.03 [0.18] m) but increased in healthy boys (mean [SD] change = 0.03 [0.18] m). Cadence decreased in boys with DMD (mean [SD] change = -9 [15] strides/min) but was stable in healthy boys (mean [SD] change = 0.02 [9] strides/min). In boys with DMD, change in 6MWD correlated strongly with change in stride length (r=0.94, p<0.0001) and change in cadence (0.71, p=0.0045). In healthy boys, change in 6MWD correlated strongly with change in stride length (r=0.73, p=0.0001) but not at all with change in cadence (r=0.002). CONCLUSIONS/RELEVANCE: This modified 6MWT shows clinically important changes over an 1-year period. These changes are age-dependent, consistent with the known natural history of DMD. Improvement or stabilization of 6MWD during the course of a long-term therapeutic trial would represent a clinically meaningful benefit for boys with DMD. Supported by: PTC Therapeutics, Inc.

Descreve a validade do uso do teste de caminhar 6 minutos na avaliação de pacientes com distrofia muscular de Duchenne.

9) Risk Factors for Fractures in the Muscular Dystrophy Surveillance, Tracking and Research Network Cohort

 Lisa A. Miller, Kathy James, Denver, CO, Katherine Mathews, Iowa City, IA, Shree Pandya, Rochester, NY, Susan Apkon, Seattle, WA, Chris Cunniff, Tucson, AZ

OBJECTIVE: To determine the occurrence of fractures and assess risk factors for fractures among the Muscular Dystrophy Surveillance, Tracking and Research Network (MD STARnet) cohort, a large population-based cohort of individuals with well-characterized dystrophinopathy. BACKGROUND: Fracture occurrence is a significant problem in Duchenne muscular dystrophy, with reported rates between 21% and 44%. DESIGN/METHODS: All males with definite or probable dystrophinopathy identified through MD STARnet who were greater than 3 years of age and had a birth year from 1982 to 2006 were included. Data were abstracted annually from medical records for all individuals with a potential dystrophinopathy in the surveillance regions of Arizona, Colorado, Iowa, Georgia and Western New York. Cox proportional hazard modeling, a complex multivariate survival analysis, was used to assess risk factors for fractures. For each patient, wheelchair use (part-time or full-time); bisphosphonate, steroid, and calcium/vitamin D use prior to fracture; and the duration of each were determined at each month of fracture occurrence. RESULTS: There were 187 first fractures among 578 individuals (32.4 percent). The most common site was the femur (31.4 percent), followed by the tibia/fibula (16.0 percent). The fracture risk for individuals who were in a wheel chair full-time was 3.2 times higher than for individuals who were ambulating, but for every month of full-time wheel chair use, risk decreased by 2.0 percent. For each additional month of steroid use beyond 6 months, fracture risk increased by 1.2 percent. Calcium/vitamin D and bisphosphonate use prior to fracture did not significantly affect risk. CONCLUSIONS/RELEVANCE: Our results confirm the high rate of fractures in individuals with dystrophinopathy and their relation to steroid use. In this population, the risk of fracture is higher during early wheel chair use and decreases over time. Fracture risk in these individuals is likely complex and the result of multiple factors. Supported by: Centers for Disease Control and Prevention Cooperative Agreement (5U01DD000191).

Descrição do risco de fraturas em Duchenne: maior risco com o uso de cortícóides, no começo do uso da cadeira de rodas e redução do risco ao longo do tempo. O risco de fraturas é um resultado de múltiplos fatores.

10) Disparities in the Diagnosis of Duchenne and Becker Muscular Dystrophy: Data from the MDSTARnet, 1999-2007

 Christopher Cunniff, Jennifer Andrews, Tucson, AZ, Emma Ciafaloni, Rochester, NY, Deborah Fox, Troy, NY, Caleb Holtzer, Zhenqiang Lu, Tucson, AZ, Lisa Miller, Denver, CO, John Meaney, Tucson, AZ

OBJECTIVE: To characterize the association of sociodemographic factors with delays at specific steps in the diagnosis of Duchenne and Becker Muscular Dystrophy (DBMD). BACKGROUND: Prior studies of DBMD observed diagnostic delays ranging from 1.9 to 4.3 years, with diagnosis occurring around age 5 years. No studies report on sociodemographic disparities in the diagnostic process. DESIGN/METHODS: We analyzed medical records for 593 boys in the MDSTARnet database and assessed mean age differences by sociodemographic group at first sign or symptom, initial medical evaluation, and first creatine kinase (CK) test using generalized linear regression models and T tests. We assessed the uptake of diagnostic testing and mutation analysis using the Cox Proportional Hazard Model. RESULTS: Family history information was available for 549 boys. Of these, 174 (29.3%) had a known family history of DBMD prior to diagnosis. Boys with a family history were diagnosed at 33 months and experienced each step to diagnosis at a younger age than boys without a family history (p<.001). Boys without a family history were diagnosed on average at 66 months. Within this group, age at evaluation was younger for boys with more educated mothers (p<.001). Whites underwent CK and DNA testing earlier than Blacks and Hispanics (p<.005). Mean ages for boys grouped by socioeconomic status or place of residence were not different at any time point. The rate of point mutation analysis following a negative deletion/duplication test was greater among boys with more educated mothers (p<.001). CONCLUSIONS/RELEVANCE: In the MDSTARnet population, children without a family history are diagnosed at age 5 years, 6 months, despite longstanding symptoms. Differences in race/ethnicity and mother education are associated with longer delays at multiple steps in the diagnostic process. The reasons for such delay are not known but may result from lack of awareness of symptoms or decreased access to diagnostic services. Supported by: A cooperative agreement from the Centers for Disease Control and Prevention through the Association of American Medical Colleges, grant number U36/CCU319276, AAMC ID number MM-1064-09/09. Publication and report contents are solely the responsibility of the authors and do not necessarily represent the official views of the AAMC or the CDC. This study was also funded by the Centers for Disease Control and Prevention under the Cooperative Agreement for Surveillance and Epidemiologic Research of Duchenne and Becker Muscular Dystrophy DD000187, DD000189, DD000190, DD000191.

Estudo epidemiológico; diagnóstico é mais precoce de Duchenne e Becker quando já há casos na família; se não o diagnóstico é feito mais tardiamente, após os 5 anos, apesar dos sintomas. Há diferença neste tempo dependendo do nivel cultural das mães e com fatores raciais.

11)  Respiratory Care Trends for Duchenne and Becker Muscular Dystrophies (DBMD): Data from the MD STARnet, 2001-2007

 Daniel A. Mandel, Atlanta, GA, Daniel W. Sheehan, Buffalo, NY, Shree Pandya, Rochester, NY, Christina P. Westfield, Deborah J. Fox, Troy, NY, Sarah K. Nabukera, Katherine Mathews, Iowa City, IA, Christopher Cunniff, Tucson, AZ, Carolyn M. Constantin, Atlanta, GA, David J. Birnkrant, Cleveland, OH

OBJECTIVE: To profile forced vital capacity (FVC) monitoring for males who have DBMD and to evaluate non-invasive positive pressure ventilation (NPPV) and mechanical insufflator/exsufflator (MI/E) use among males with very low FVC measurements. BACKGROUND: Semiannual FVC measurements are recommended for patients age > 12 who have Duchenne muscular dystrophy. FVC measurements of < 1 L are associated with complications of hypoventilation and early mortality. NPPV and MI/E are used to support patients with poor pulmonary function. DESIGN/METHODS: MD STARnet is a population-based surveillance system that identifies all patients who have DBMD in defined geographic areas. MD STARnet records were analyzed for 132, 177, and 199 males age > 12 in 2001, 2004, and 2007, respectively. Inclusion criteria for FVC < 1L were: > 5 recorded FVC measurements; > 2 consecutive FVC measurements < 1 L; and no subsequent FVC measurements > 1L. Sample sizes for FVC < 1 were 11, 22, and 33 in 2001, 2004, and 2007, respectively. Logistic regression models were used to investigate NPPV and MI/E use over time, clustering on patient. RESULTS: The percentage of males who have DBMD age > 12 years with a recorded FVC measurement ranged from 60-65% in the three study years. The rates of NPPV use significantly increased among males with FVC < 1L (Wald X2 = 11.5, p = .003) over the study period. NPPV rates ranged from a low of 27% in 2001 to a high of 85% in 2007. Rates of MI/E use followed a less clear pattern: 18% in 2001; 9% in 2004, 58% in 2007. CONCLUSIONS/RELEVANCE: Data show consistent FVC monitoring for males who have DBMD and increasing use of NPPV for males who have very low FVC measurements between 2001 and 2007. MI/E was relatively underused compared with NPPV. Supported by: CDC cooperative agreements DD000187, DD000189, DD000190, and DD000191.

Estudo da função respiratória na distrofia muscular de Duchenne e o uso da ventilação não invasiva no período de 2001 a 2007.

12) Neuropsychological Profile of Adult Patients with Duchenne Muscular Dystrophy

 Natalia Sierra, Lilia Mesa, Alberto Dubrovsky, Pablo Sojo, Teresa Torralva, María Roca, Fernando Chloaca, Laura Pirra, Facundo Manes, Buenos Aires, Argentina

OBJECTIVE: To analyze the cognitive profile of adult patients with normal IQ diagnosed with Duchenne Muscular Dystrophy (DMD). BACKGROUND: Research on muscular dystrophies has focused extensively on the impact of peripheral neural structures affected by the degenerative nature of the disease. However, investigating the cognitive impairment in these patients may contribute to the understanding of the pathophysiological changes occurring on the central nervous system (CNS) and its relationship with peripheral structures. DESIGN/METHODS: Ten patients with diagnosis of DMD aged between 17 and 28 years were assessed with a general comprehensive cognitive battery as well as a specific executive battery. All patients had within normal IQ scores. RESULTS: Tasks associated with a motor component such as the Complex Rey Figure (z= -2,02) and TMT-A (z= -2,31) and TMT-B (z=-2,47) were impaired. Performance deficits were also found on tasks of verbal inhibitory control (z=-3,02) with normal scores on reading speed (z=-0,69) and color naming (z=-0,81) on the Stroop task. Decreased scores were observed for tasks of theory of mind (z=-1,19) and decision-making (Iowa Gambling Task), although performance on the latter did not correlate significantly with theory of mind or verbal inhibitory control scores (both p > .05). CONCLUSIONS/RELEVANCE: These results are in accordance with previous studied (e.g. Hinton et al, 2007) and suggest that normal IQ patients with DMD present theory of mind and verbal inhibitory control deficits. Our results also revealed decision-making impairments, although apparently not associated with theory of mind and executive deficits.

Estudo através de testes das funções cognitivas em pacientes com distrofia muscular de Duchenne e QI normal demonstrando deficit do controle inibitório verbal.

13) Pulmonary Function Characteristics of Boys with Duchenne and Becker Muscular Dystrophy by Age Groups and Steroid Use: One-Year Data from the CINRG Longitudinal Study Project

 R. Ted Abresch, Craig M. McDonald, Davis, CA, Jay J. Han, Sacramento, CA, Robert Leshner, Washington, DC, Diana Escolar, McLean, VA, Avital Cnaan, Eric Hoffman, Adrienne Arrieta, Tina Duong, Fenming Hu, Washington, DC, Julaine Florence, Saint Louis, MO, CINRG Investigators, Washington, DC

OBJECTIVE: To describe the pulmonary function characteristics of Duchenne Muscular Dystrophy (DMD) over a one-year time period. BACKGROUND: Lack of well-characterized pulmonary function data inhibits the development of therapeutic clinical trials in DMD. DESIGN/METHODS: Pulmonary function tests (PFTs) were performed in subjects with confirmed DMD at ages <7, 7-12, 13-18 and > 18 in 20 centers from the Cooperative International Neuromuscular Research Group at baseline and 12 months. Fifteen percent of subjects were steroid nave. Pulmonary function measures included absolute and % predicted forced vital capacity (FVC and %FVC), forced expiratory volume in 1 second a (FEV1, %FEV1), peak expiratory flow rate (PEFR, %PEFR), maximum inspiratory pressure (MIP, %MIP), and maximum expiratory pressure (MEP, %MEP). Significance was accepted at p < 0.05. RESULTS: There was a significant one-year increase in FVC (0.15l 0.1 [sd]), FEV1 (0.15l 0.2) and PEFR (0.49 l/s 0.5) in the <7 year age groups (n=10). There was a significant one-year increase in FVC and FEV1 (0.11l 0.2 and 0.13l 0.2, respectively; n=85), as well as MIP and MEP (3.7 cmH20 12.5 and 5.7 cmH20 10.9, respectively; n = 102) in the 7-12 year age groups. There was a significant one-year decline in %FVC and %PEFR (-5.8% 5.7 and 5.0% 10.3, respectively) in the 13-18 year age groups (n=57). At age 19 (n=23) there was a significant one-year decline in FVC (-0.14l 0.2), %FVC (-3.0% 3.4), FEV1 (-0.14l 0.2), %FEV1 (-3.6% 3.9), %PEFR (-3.5% 6.5) and %MIP (-2.7% 2.8). No other PFT measures exhibited significant differences over a one-year period. CONCLUSIONS/RELEVANCE: Pulmonary function testing reflects changes associated with growth at age groups <7 and 7-12. DMD subjects exhibit significant one-year PFT declines in the 13-18 and >18 year age groups. Supported by: National Institute of Disability and Rehabilitation Research Grant H133B980008-03; National Institutes of Health Grant 1U54HD053177-01A1; Department of Defense Grant 0616USAMRAA.

Estudo de um ano da função pulmonar na Distrofia muscular de Duchenne, demonstrando significante declínio da função pulmonar após os 13 anos.

14) Functional Motor Performance Characteristics of Boys with Duchenne Muscular Dystrophy by Age Groups and Steroid Use: One-Year Data from the CINRG Longitudinal Study Project

 Craig McDonald, Erik Henricson, Sacramento, CA, Richard T. Abresch, Davis, CA, Jay J. Han, Sacramento, CA, Robert Leshner, Washington, DC, Diana Escolar, McLean, VA, Eric Hoffman, Avital Cnaan, Addrienne Arrietta, Fenming Hu, Angela Zimmerman, Tina Duong, Washington, DC, Julaine Florence, Saint Louis, MO, CINRG Investigators, Washington, DC

OBJECTIVE: To describe the changes in timed function testing (TFT) in Duchenne muscular dystrophy (DMD) over one-year and the predictive value of TFTs for determining loss of ambulation. BACKGROUND: In DMD, TFT measures are used as clinical endpoints for therapeutic clinical trials and may predict loss of ambulation over one-year. DESIGN/METHODS: TFTs were performed in 255 subjects with confirmed DMD at ages <7, 7-12, and >13 in 20 centers from the Cooperative International Neuromuscular Research Group at baseline and 12 months. Fifteen percent of subjects were steroid nave. TFTs (in seconds) included run/walk 10 meters, climb 4 steps, and standing from lying. Significance was accepted at p < 0.05. RESULTS: There was a mean decrease in all TFTs over one-year for the <7 year group (n=56): run/walk 10 meters (-0.46 1.7[sd]), climb 4 steps (-1.83 4.4) and standing from lying (-0.65 2.9). There was a significant one-year increase in all TFTs in 7-12 year olds (n=65): run/walk 10 meters (+1.38 1.8), climb 4 steps (+2.47 4.9) and standing from lying (+3.42 6.1). Those >13 also increased time to run/walk 10 meters (+3.21 5.2, n=10) and climb 4 steps (+1.58 1.3, n=7). Only one subject >13 was able to perform standing from lying. Loss of ambulation over 12 months was compared for three groups: baseline run/walk 10 meters < 6 seconds, 6-12 seconds, and >12 seconds. Survival analysis for the milestone of loss of ambulation showed all three groups to be significantly different using a Log-rank test (p<0.0001). CONCLUSIONS/RELEVANCE: In DMD, TFTs show relative improvement with time in younger subjects <7 years. For those 7 and older TFTs show disease-related progression in both steroid-users and steroid-nave subjects. Timed to run/walk 10 meters is predictive of loss of ambulation over the following 12 months. Supported by: National Institute of Disability and Rehabilitation Research Grant H133B980008-03; National Institutes of Health Grant 1U54HD053177-01A1; Department of Defense Grant 0616USAMRAA

Estudo de um ano da função motora em pacientes com Duchenne. O estudo da marcha em 10 metros foi preditivo da parada de deambulação após 12 meses. 

15) A Cooperative International Neuromuscular Research Group (CINRG) Study of the Relationship between Impairment, Activity Limitation, Participation and Quality of Life in Persons with Confirmed Dystrophinopathies: One Year Follow-Up of Skeletal Muscle Strength and Timed Motor Performance

Erik Henricson, Craig McDonald, Sacramento, CA, Richard Abresch, Davis, CA, Jay Han, Sacramento, CA, Robert Leshner, Eric Hoffman, Washington, DC, Diana Escolar, McLean, VA, Avital Cnaan, Fengming Hu, Angela Zimmerman, Tina Duong, Washington, DC, Julaine Florence, Saint Louis, MO, Adrienne Arrieta, CINRG Investigators, Washington, DC

OBJECTIVE: To evaluate 12-month change in skeletal muscle strength and timed motor function tests in individuals with Duchenne muscular dystrophy (DMD) aged 2-28 years. BACKGROUND: Lack of adequate natural history data in steroid-treated DMD and lack of well-characterized outcome measures across age ranges limits the ability to assess therapeutic effectiveness in clinical trials in DMD. DESIGN/METHODS: We enrolled males with confirmed DMD from 20 participating centers from 10 countries of the Cooperative International Neuromuscular Research Group (CINRG). Ambulatory and transitioning participants underwent strength assessment (modified MRC manual muscle test (MMT), quantitative muscle tests (QMT) of grip, elbow flexion/extension, knee flexion/extension) and timed function tests ((TFT) stand from supine, run/walk 10m, climb 4 stairs) at baseline, and months 3, 6, 9, 12. RESULTS: 255/347 males with DMD aged 2 to 28 years of age underwent strength and functional testing, and 15% were glucocorticoid-nave. Significant changes over 12 months included: Children <7 years decreased time to climb 4 steps by 1.83(SD=4.4)s (p<0.0001 N=56) and increased quantitative grip strength by 2.96(SD=2.5)lbs (p<0.0001 N=37) and knee flexors by 1.18(SD=2.6)lbs (p<0.04 N=37). Children aged 7-12 years increased time to run/walk 10m by 1.38(SD=1.8)s (p<0.0001 N=65), time to climb 4 stairs by 2.47(SD=4.9)s (p<0.0001 N=65) and time to stand from supine by 3.42(SD=6.1)s (p<0.0001 N=65). Children aged 13-18 years decreased quantitative elbow extensor strength by 1.23(SD=1.1)lbs (p<0.001 N=61) and elbow flexor strength by 0.98(SD=1.3)lbs (p<0.01 N=61) and decreased manual muscle test score by 0.32(SD=0.4) points (p<0.01 N=61). Adults aged >18 years who were testable decreased quantitative grip strength by 0.6(SD=0.9)lbs (p<0.02 N=31). CONCLUSIONS/RELEVANCE: Few measures of strength and function in steroid-treated boys with DMD show significant disease-related changes over one-year. Relative stability over this time suggests that clinical trials must demonstrate improvement rather than stabilization using these measures. Supported by: National Institute of Disability and Rehabilitation Research Grant H133B980008-03 National Institutes of Health Grant 1U54HD053177-01A1 Department of Defense Grant 0616USAMRAA.

Estudo de um ano das alterações de força muscular em pacientes com Duchenne de 2 a 28 anos, demonstrando poucas alterações em um pequeno intervalo de tempo.

16) Multiple Sclerosis in a Patient with Duchenne Muscular Dystrophy

 Adrienne A. Salomon, Negar Sodeifi, Babak Movassaghi, David Libell, Morgantown, WV

OBJECTIVE: To describe a rare association of multiple sclerosis (MS) in a patient with Duchenne Muscular Dystrophy (DMD). BACKGROUND: MS is an autoimmune disorder that most commonly begins between ages 20 and 40, but can be seen at any age. The average age at diagnosis is 31 years in males. DMD is an X-linked disorder which affects the DYS gene. It is the most common muscular dystrophy and carries an average life expectancy ranging from early teens to mid30s. No reported association between these two conditions was found. DESIGN/METHODS: Case report involving a 23-year-old man with known DMD who presented with unilateral left eye blurry vision. The patient admitted to having suffered a similar episode of visual changes approximately one year prior. Examination revealed left eye visual acuity of 20/100 with abnormal enhancement of the left optic nerve on MRI consistent with optic neuritis. MRI of the brain demonstrated multiple periventricular and juxtacortical lesions with post-contrast enhancement. Lumbar puncture was significant for increased oligoclonal bands with elevated IgG index (1.63) and myelin basic protein (3.5g/L). While the patient's diagnosis of DMD had previously been established by neurological examination, family history, elevated creatine kinase levels, and DNA analysis, the patient's new findings were consistent with a diagnosis of MS based on McDonald criteria. RESULTS: The patient received high-dose intravenous solumedrol for three days. The patient improved minimally during his hospital course and was discharged on a steroid taper. Follow-up examination confirmed resolution of his blurry vision with no further symptoms at six months. CONCLUSIONS/RELEVANCE: We report the rare association between DMD and MS. The patient's clinical course suggests that DMD did not impact the clinical course or treatment of his MS. The fact that many DMD patients do not survive long enough to manifest symptoms of MS may partly explain the rare association of these two disorders.

Descrição de um caso raro: paciente com Duchenne e que desenvolve a esclerose múltipla, uma doença auto-imune.

17) Expression of Heat Shock Proteins in Skeletal Muscle from Idiopathic Inflammatory Myopathy and Duchenne Muscular Dystrophy Patients

 Jan L. De Bleecker, Kim K. Creus, Ghent, Belgium, Jean-Jacques Martin, Antwerp, Belgium, Joachim Weis, Aachen, Germany, Boel De Paepe, Ghent, Belgium

OBJECTIVE: To investigate heat shock protein families 70 (HSP70) and HSP90 in idiopathic inflammatory myopathies (IIM) and Duchenne Muscular dystrophy (DMD). BACKGROUND: HSP70 and HSP90 chaperones assure proper protein folding and activity. Furthermore, HSP90 enhances the cytotoxic activity of inflammatory cells. In view of current approaches exploring anti-HSP90 therapy in inflammatory diseases, more in-depth knowledge of the individual pros and cons of chaperones could be relevant. DESIGN/METHODS: The expression of HSP70 and HSP90 was investigated in muscle biopsies from controls, and from IIM and DMD patients using immunofluorescence, in situ hybridization and Western blotting. RESULTS: Inflammatory cells in IIM and DMD expressed low levels of HSP70, HSP90 expression was increased in macrophages and cytotoxic T-cells in proximity of invaded nonnecrotic myofibers of PM/IBM. HSP90alpha mRNA was localized in endomysial infiltrates of PM/IBM along with faint HSP90beta expression. Part of the invaded nonnecrotic myofibers showed sarcolemmal staining for HSP70 and HSP90 proteins. The sarcoplasm of most small fibers, and some normal appearing myofibers were strongly HSP70 positive. Double staining showed important overlap between HSP70 and HSP90alpha in small NCAM+ fibers, and rare co-localization with HSP90beta. Western blotting detected HSP70 and HSP90 proteins in all muscle tissues, but protein levels were increased in all (HSP70) or part of (HSP90) IIM/DMD patients. In normal controls that had received glucocorticoids prior to biopsy, nuclear over cytoplasmic protein ratios were increased for HSP70, and decreased for HSP90. CONCLUSIONS/RELEVANCE: Our data appoint pathological and physiological roles for HSP70 and HSP90, ascribing these factors both adverse and beneficiary potential. On the one hand, HSP90 was associated with the active invasion targeting the nonnecrotic myofibers in PM/IBM. On the other hand, a strong expression of HSP70 occured in myofibers at different regeneration-stages, with important but no absolute overlap with HSP90 in the small regenerating muscle fibers, indicating both general and member-specific involvement. Supported by: L'Association Franaise contre les Myopathies (AFM, France) L'Association Belge contre les Maladies neuro-Musculaires (ABMM, Belgium) The Muscular Dystrophy Association (MDA, USA).

Pesquisa que estuda proteínas musculares que podem estar emvolvidas na necrose e regeneração muscular na distrofia muscular de Duchenne.

18) Adult Murine Derived Mesoangioblasts Successfully Recovered Dysferlin Expression in a Murine Model of Dysferlinopathy

 Jordi Díaz-Manera, Barcelona, Spain, Thierry Touvier, Rossana Tonlorenzi, Laura Perani, Arianna Dellavalle, Graziella Messina, Patrizia Pessina, Milano, Italy, Eduard Gallardo, Isabel Illa, Barcelona, Spain, Yvan Torrente, Giulio Cossu, Milano, Italy

OBJECTIVE: Our aim was to treat a mouse model of dysferlinopathy with transplantation of adult derived murine mesoangioblasts (mMABs). BACKGROUND: Mutations in dysferlin gene produce a muscular dystrophy characterized by adult onset and progressive weakness leading to a severe phenotype. The A/J mouse is a good model to study cell therapy as it completely lacks dysferlin and develops a slowly progressive muscular dystrophy. Mesangioblasts (MABs) are vessel associated progenitors that has been successfully used in preclinical models for cell therapy for muscular dystrophy including the a-sarcoglycan null mice and the Golden Retriever dogs affected by Duchenne's disease. DESIGN/METHODS: Murine mesoangioblasts were obtained from skeletal muscle of 8 days old wild type mice (C57 strain), and labeled with a lentiviral vector expressing nuclear LacZ. To avoid an immunological response, A/J-SCID mice were generated by crossing A/J and SCID strains. Firstly, we performed a single intramuscular injection of 5x105 mMABs both in cardiotoxin treated and untreated muscles from 5 months old mice. Then we proceed with a single injection of 5x105 mMABs in the right femoral artery. We analyzed the expression of dysferlin 3 weeks after the injection using immunofluorescence, quantitative RT-PCR and Western-Blot. RESULTS: The first dystrophic features in AJ-SCID mice appeared at 4-5 months of age, without significant differences in the progression and distribution of them compared with control A/J mice. Three weeks after transplantation, multiple areas of injected muscles expressed dysferlin which was absent in non-injected contralateral muscles. Presence of the protein in the membrane of Lac-Z + fibers was also demonstrated in intra-arterially injected animals. The expression of dysferlin was significantly higher in muscles treated with cardiotoxin. CONCLUSIONS/RELEVANCE: Treatment with wild type mMABs successfully recovered the expression of dysferlin in A/J-SCID mice. This fact suggests that adult derived mesoangioblasts may be a promising candidate for future cell-therapy protocols in dysferlinopathy patients. Supported by: European Federation of Neurology grant for young neurologist.

Pesquisa em camundongos deficientes em disferlina e tratados com mesangioblastos, células tronco de vasos. Os resultados foram positivos com expressão significativa da disferlina nos animais.

 19) rAAV5 Mediated Delivery of Dysferlin as a Therapeutic Strategy for LGMD2B and Miyoshi Myopathy

 Louise R. Rodino-Klapac, Kimberly M. Shontz, Chrystal Montgomery, Vinod Malik, Nancy Davis, Paul M. L. Janssen, K. Reed Clark, Columbus, OH, Robert H. Brown, Worcester, MA, Jerry R. Mendell, Columbus, OH

OBJECTIVE: To develop an adeno-associated virus (AAV) mediated therapeutic transgene to treat dysferlinopathies including limb-girdle muscular dystrophy (LGMD) type 2B and Miyoshi myopathy (MM). No therapeutic treatments are currently available for these disorders. BACKGROUND: The size of the DYSF cDNA (6.5 kb) negates packaging into traditional AAV serotypes (capacity < 4.7 kb) known to express well in muscle (i.e. rAAV1, 2, 6, 8). Potential advantages of a full cDNA versus a truncated transgene include: maintaining structural-functional protein domains, evading protein misfolding, and avoiding novel epitopes that could be immunogenic. This work describes in vivo delivery of AAV5.DYSF to limb muscle and diaphragm of dysferlin deficient (Dysf-/-) mice by both intramuscular and vascular (femoral artery) approaches. DESIGN/METHODS: A cassette containing the DYSF cDNA driven by the muscle specific MHCK7 promoter was packaged into an AAV2/5 vector. Physiological characterization of three dysferlin deficient mouse strains (AJ, SJL, and 129-Dysftm1Kcam/J ) revealed functional deficits in the diaphragm but not skeletal muscle. Efficacy of rAAV5.MHCK7.DYSF gene replacement was tested following intramuscular and intravascular delivery to skeletal muscle and diaphragm of 4-6 week old Dysf -/- mice. Functional improvement was measured by tetanic force and resistance to fatigue in the diaphragm at 2 months. RESULTS: Robust dysferlin gene expression was achieved in a dose-dependent manner by both intramuscular and vascular approaches. Western blot analysis confirmed the immunostaining results demonstrating a 237kDa band in treated samples that was absent in controls. Band intensity correlated with dose. Gene transfer improved both force generation and resistance to fatigue in the functionally impaired diaphragm in Dysf-/- mice. CONCLUSIONS/RELEVANCE: These results provide proof of principle that a full-length dysferlin cDNA can be delivered efficiently to muscle using AAV5 leading to physiological improvement. Future studies in a larger animal model using a vascular approach targeting multiple muscles will guide clinical trial design for LGMD2B and MM patients. Supported by: Day Foundation.

Pesquisa experimental que demonstra bons resultados em camundongos deficientes em disferlina e tratados com vetor viral transportando o gene da disferlina.

20) Progressive Dysphagia in Limb Girdle Muscular Dystrophy Type 2B: An Extension of the Clinical Phenotype

 Richard A. Walsh, Fiona Hill, Francesca M. Brett, Dublin, Ireland, Richard Charlton, Rita Barresi, United Kingdom, Dominick J. H. McCabe, Dublin, Ireland

OBJECTIVE: Genetically-confirmed autosomal recessive limb girdle muscular dystrophy type 2B (LGMD2B) typically presents in early adulthood with lower more than upper limb-girdle weakness. Facial muscles are usually spared and dysphagia has not been reported as part of the phenotype. BACKGROUND: We present this case report as an important extension of the clinical phenotype of LGMD2B. DESIGN/METHODS: A 40 year-old woman with non-specific generalised clumsiness since age 10 had a 7 year history of progressive proximal lower limb weakness followed by mild upper limb weakness. She also reported progressive subjective dysphagia for solids and liquids resulting in recurrent respiratory infections. Neurological examination revealed mild bilateral facial weakness, neck flexor more than extensor muscle weakness, mild proximal upper limb weakness, severe proximal and mild distal lower limb weakness. Upper limb reflexes were reduced with lower limb areflexia and a myopathic gait. RESULTS: Creatine kinase has varied between 3588 and 8058 IU/L (normal 34170). Quadriceps muscle biopsy showed features of an acute-on-chronic myopathy. Western blot analysis indicated a dysferlinopathy and genetic testing confirmed two pathogenic mutations in the dysferlin gene on chromosome 2p13: (DYSF c.5908 C>T, p.Pro1970Ser and DYSFc353delT). Videoflouroscopy revealed penetration of the airway above the vocal cords. Esophagogastroduodenoscopy identified impaired esophageal relaxation and barium swallow demonstrated significant delay in swallow initiation and tertiary esophageal peristaltic contractions. CONCLUSIONS/RELEVANCE: Dysphagia must now be considered part of the phenotypic spectrum of LGMD2B. Pharyngeal and esophageal involvent may have arisen as a consequence of the particular combinaltion of gene mutations in this patient although no good genotype-phenotype correlation has been descrined in LGMD2B. The case is important in alerting physicians to the need to screen this patient group for symptoms of dysphagia. Also, misdiagnosis of LGMD2B as polymyositis is not uncommon. The presence of dysphagia should not be a further deterrent in considering a dysferlinopathy in the appropriate clinical setting. Supported by: The Diagnostic and Advisory Service for Rare Neuromuscular Disorders is Funded by the NHS National Commissioning Group.

Pesquisa que descreve dificuldades progressivas da deglutição (disfagia) em pacientes com distrofia tipo cinturas; este sintoma não tinha sido descrito com frequência nesta forma de distrofia e que deveria ser pesquisado nestes pacientes.

 21) Muscle Imaging in Oculopharyngeal Muscular Dystrophy

 Celedonio Marquez, Carmen Paradas, Seville, Spain, Montse Olive, Hospitalet de Llobregat, Barcelona, Spain, Juan Bautista, Jose Manuel Morales, Antonio Cano, Seville, Spain, Fernando Castellanos, Plasencia, Caceres, Spain, Laura Gonzalez, Hospitalet de Llobregat, Barcelona, Spain, Ricard Rojas, Barcelona, Spain, Raul Garcia, Seville, Spain

OBJECTIVE: To describe muscle imaging findings in a cohort of patients with Oculopharyngeal Muscular Dystrophy (OPMD). BACKGROUND: Muscle imaging has become a useful tool in identifying patterns of muscle involvement in neuromuscular disorders. It can be relevant for diagnosis and assessment of progression. DESIGN/METHODS: We obtained lower extremities muscle imaging studies (12 CT scans, 35 MRI) in 47 carriers of a mutation in the PABPN1 gene: 4 asymptomatic carriers of a (GCN)13 repeat (2 women, mean age 37.55.3), and 43 OPMD patients (22 women, mean age 65.410.3): 3 patients with a (GCN)12 repeat, 25 (GCN)13, 1 (GCN)14, 2 (GCN)15, 1 (GCN)16, 1 (GCN) 17. We described the muscle imaging findings and compared the groups with normal and abnormal imaging studies. RESULTS: The four asymptomatic carriers showed no abnormalities on the MRI. Muscle imaging was normal in 10 patients (23.3%) and abnormal in 33 patients (76.7%). The abnormalities were decreased attenuation on CT scans or high signal on T1-weighted MRI consistent with fatty infiltration in gluteus maximus, hip adductors or soleus muscles. The mean evolution of disease was longer in the abnormal imaging group (11,61 8.08 years) than in the normal imaging group (3.52.13 years)(p=0.013). Proximal muscle weakness in lower limbs was present in 18 out of 33 (54.5%) patients with abnormal muscle imaging and in no patients with normal findings. CONCLUSIONS/RELEVANCE: Fatty infiltration of gluteus maximus, hip adductors or soleus muscles represents a characteristic pattern of muscle involvement in OPMD. This radiologic involvement is not a early feature of the disease. Muscle imaging of lower limbs can be useful in diagnosing and monitoring progression of OPMD patients in clinical practice and research. Supported by: FIS 060382

Pesquisa que descreve o uso da ressonância nuclear magnética no estudo dos músculos na distrofia óculo-faríngea.

Japão - a placenta é rica em células que podem originar músculos; os autores utilizaram 6 tipos diferentes de células placentárias para tratamento de camundongos com distrofia muscular; a utilização destas células em camundongos mantidos com imunossupressão resultou em expressão de distrofina humana nestes camundongos. O estudo destas células permitirá escolher aquelas com melhor potencial para tratamento das distrofias musculares.

Japão - em trabalho anterior os autores já tinham descrito o tratamento de escoliose (desvio lateral da coluna em pacientes com distrofia muscular de Duchenne e função pulmonar muito baixa. Neste trabalho eles relatam o seguimento a longo prazo destes pacientes. Os pacientes relataram satisfação e melhor qualidade de vida após a cirurgia. A capacidade pulmonar continuou a se reduzir em 3,6% ao ano, apesar dos pacientes continuaram com os exercícios respiratórios. A conclusão final foi positiva a longo prazo com este tratamento

Itália - muitas vezes a biópsia muscular é necessária para diagnóstico das distrofias e muitas vezes biópsias repetidas são necessárias para acompanhamento de tratamentos experimentais. Neste estudo pequenas biópsias da pele em volta dos lábios foram realizadas para estudo de pequenos músculos que se localizam em volta da pele. O estudo das proteínas destes músculos se mostrou viável e menos invasiva que a biópsia muscular convencional mostrando-se uma boa alternativa para estudo ou diagnóstico das distrofias musculares.

China - neste trabalho os autores descrevem os resultados do tratamento com células tronco (de medula óssea e de corfão umbilical) em pacientes com distrofia muscular. Não é possível confiar plenamente nos resultados porque o artigo tem vários pontos não esclarecidos; o texto é publicado em chinês e as poucas informações estão no resumo em inglês; o resumo diz que foram tratados 82 pacientes com distrofia muscular progressiva mas não diz a forma da doença; os resultados foram considerados bons mas os critérios de avaliação não foram objetivos; eles não descrevem efeitos colaterais.

Japão - o cromossomo humano artificial (HAC) tem vantagens sobre os vetores virais para tratamento das doenças genéticas. Células tronco multipotentes induzidas podem ser úteis para tratamento por serem são retiradas do próprio paciente Nesta pesquisa HAC foi utilizado para corrigir o defeito genético de células tronco multipotentes induzidas do camundongo com distrofia e das células de pacientes com Duchenne. Os resultados demonstraram uma significativa expressão da distrofina nas células tratadas (em torno de 90%). Ou seja a combinação de terapia gênica com células tronco pode ser um caminho para o tratamento da distrofia muscular de Duchenne. O resumo em inglês pode ser lido abaixo:

(Molecular Therapy 2010;18(2):386–393) Complete Genetic Correction of iPS Cells From Duchenne Muscular Dystrophy

Yasuhiro Kazuki, Masaharu Hiratsuka, Masato Takiguchi, Mitsuhiko Osaki, Naoyo Kajitani, Hidetoshi Hoshiya, Kei Hiramatsu, Toko Yoshino, Kanako Kazuki, Chie Ishihara, Shoko Takehara, Katsumi Higaki, Masato Nakagawa, Kazutoshi Takahashi, Shinya Yamanaka and Mitsuo Oshimura - Japan

Human artificial chromosome (HAC) has several advantages as a gene therapy vector, including stable episomal maintenance that avoids insertional mutations and the ability to carry large gene inserts including the regulatory elements. Induced pluripotent stem (iPS) cells have great potential for gene therapy, as such cells can be generated from the individual's own tissues, and when reintroduced can contribute to the specialized function of any tissue. As a proof of concept, we show herein the complete correction of a genetic deficiency in iPS cells derived from Duchenne muscular dystrophy (DMD) model (mdx) mice and a human DMD patient using a HAC with a complete genomic dystrophin sequence (DYS-HAC). Deletion or mutation of dystrophin in iPS cells was corrected by transferring the DYS-HAC via microcell-mediated chromosome transfer (MMCT). DMD patient- and mdx-specific iPS cells with the DYS-HAC gave rise to differentiation of three germ layers in the teratoma, and human dystrophin expression was detected in muscle-like tissues. Furthermore, chimeric mice from mdx-iPS (DYS-HAC) cells were produced and DYS-HAC was detected in all tissues examined, with tissue-specific expression of dystrophin. Therefore, the combination of patient-specific iPS cells and HAC-containing defective genes represents a powerful tool for gene and cell therapies.

USA - timosina beta 4 é uma proteína envolvida na proliferação e diferenciação celular e que interfere com vários mediadores inflamatórios. Os camundongos portadores de distrofia foram tratados por 6 meses. Os camundongos tratados apresentaram maior número de fibras em regeneração em relação aos não tratados. Os demais parâmetros estudados como força muscular, ecocardiograma e fibrose cardíaca não tiveram alteração com o tratamento.

Brasil - Ministério da Saúde divulgou hoje calendário de vacinação contra a gripe A (H1N1). Pacientes com distrofia muscular serão vacinados juntamente com a população portadora de outras doenças mais propensas a complicações dos quadros gripais como os obesos, cardíacos, etc. A vacinação ocorrerá de 22 de março a 2 de abril.  Importante lembrar que os portadores de distrofia muscular deverão receber também  vacina habitual contra as outras cepas do vírus da gripe (vacinação normal dos outros invernos).

USA - na distrofia miotônica é frequente a resistência a insulina que pode levar ao diabetes mellitus; pacientes com resistência a insulina são mais predispostos a ter doença gordurosa não alcoólica do fígado. Esta doença não havia sido estudada na distrofia miotônica; 36 pacientes foram estudados e 44% apresentavam testes hepáticos alterados  e  87% deles apresentavam doença gordurosa do fígado. Além disso apresentavam triglicérides e colesterol elevados, insulina de jejum elevada, obesidade abdominal entre outras alterações. Sugere-se então o melhor controle destas alterações com dieta e medicação para evitar a doença gordurosa não alcoólica do fígado. O resumo em inglês pode ser lido abaixo:

(Muscle & Nerve, 2009) Frequency and predictors of nonalcoholic fatty liver disease in myotonic dystrophy

Kenneth Shieh,  James M. Gilchrist, Kittichai Promrat - USA

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease that is strongly associated with insulin resistance. Myotonic dystrophy (DM1) is the most common form of adult-onset muscular dystrophy, and there is a high frequency of insulin resistance due to insulin receptor mRNA splicing defects in muscle tissue. The frequency and predictors of NAFLD in this population have not been described. Thirty-six patients with DM1 were prospectively assessed for the presence of NAFLD and insulin resistance. NAFLD was defined by abnormal liver chemistry tests with ultrasound or pathologic evidence of steatosis in the absence of other liver disease. Abnormal liver chemistry tests were found in 44% of DM1 patients (mean ALT 73 ± 21 U/L, AST 53 ± 15 U/L), and 87% were attributable to NAFLD. Clinical predictors of NAFLD included increased insulin resistance by the homeostasis model assessment (HOMA) method (9.5 vs. 4.0 U, P = 0.03), elevated fasting insulin (40.4 vs. 16.1 IU/ml, P = 0.03), abdominal obesity (98.6 vs. 90.8 cm, P = 0.03), elevated triglycerides (195.7 vs. 136.8 mg/dl, P = 0.02), and elevated total cholesterol (213.6 vs. 180.6 mg/dl, P = 0.02). NAFLD is very common and should be considered in the management of DM1. It is strongly associated with markers of insulin resistance and features of the metabolic syndrome. These findings support the role of peripheral insulin resistance in the pathogenesis of NAFLD

USA - a empresa Cytokinetics tem estudado pequenas moléculas para tratamento dos sintomas das doenças musculares (cardíacas e esqueléticas); esta semana eles divulgaram os resultados do estudo fase 1 (teste da droga em pessoais sem doença alguma) da droga CK-2017357, uma droga que ativa uma proteína muscular relacionada com a função muscular; esta droga já tinha demonstrado resultados positivos em camundongos para melhorar a força, diminuir o cansaço e melhorar os sintomas cardíacos e musculares em diversas doenças. Neste relato a droga testada em humanos causou aumento siginifcativo da força muscular e deverá continuar em testes em pessoas saudáveis até que se determine a segurança e a dose necessária para uso em doenças neuromusculares.

França -  em geral as manifestações cardíacas na distrofia muscular de Duchenne são atribuídas a fibrose do músculo cardíaco e podem levar a arritmias graves e fatais. Muitas vezes as alterações elétricas do coração ocorrem sem o apareciemnto da fibrose; neste estudo os autores descrevem um canal de cálcio defeituoso no músculo cardíaco de camundongos com distrofia muscular que poderiam desencadear arritmias ventriculares. O uso de medicações que corrigem o funcionamento deste canal previnem o aparecimento das arritmias. Estas medicações ainda são estudadas somente experimentalmente em camundongos. O resumo em inglês pode ser lido abaixo:

(PNAS, 2010) Leaky RyR2 trigger ventricular arrhythmias in Duchenne muscular dystrophy

Jérémy Fauconnier; Jérôme Thireau; Steven Reiken; Cécile Cassana; Sylvain Richarda; Stefan Matecki; Andrew R. Marks; Alain Lacampagne - France

Patients with Duchenne muscular dystrophy (DMD) have a progressive dilated cardiomyopathy associated with fatal cardiac arrhythmias. Electrical and functional abnormalities have been attributed to cardiac fibrosis; however, electrical abnormalities may occur in the absence of overt cardiac histopathology. Here we show that structural and functional remodeling of the cardiac sarcoplasmic reticulum (SR) Ca2+ release channel/ryanodine receptor (RyR2) occurs in the mdx mouse model of DMD. RyR2 from mdx hearts were S-nitrosylated and depleted of calstabin2 (FKBP12.6), resulting in “leaky” RyR2 channels and a diastolic SR Ca2+ leak. Inhibiting the depletion of calstabin2 from the RyR2 complex with the Ca2+ channel stabilizer S107 (“rycal”) inhibited the SR Ca2+ leak, inhibited aberrant depolarization in isolated cardiomyocytes, and prevented arrhythmias in vivo. This suggests that diastolic SR Ca2+ leak via RyR2 due to S-nitrosylation of the channel and calstabin2 depletion from the channel complex likely triggers cardiac arrhythmias. Normalization of the RyR2-mediated diastolic SR Ca2+ leak prevents fatal sudden cardiac arrhythmias in DMD.

 

 

 

 

 

 

 

                           

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