News in Muscular Dystrophy

 

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BRAZILIAN RESEARCH CENTER - IMPORTANT INFORMATIONS

TAMOXIFEN INCREASES MUSCULAR STRENGTH OF THE MDX DYSTROPHIC MICE NEW

DECEMBER/2004

30/12/04: PTC Therapeutics: FAQ

30/12/04: (In Press: Biochimica et Biophysica Acta,2004) Up-regulation of mitogen activated protein kinases in mdx skeletal muscle following chronic treadmill exercise

 Akinori Nakamura, Kunihiro Yoshida, Hideho Ueda, Shin’ichi Takeda, Shu-ichi Ikeda - Japan

 Abstract

 Dystrophin, a product of the Duchenne muscular dystrophy gene, is a cytoskeletal protein of skeletal and cardiac muscle fibers. Dystrophin-deficient muscle fibers are abnormally vulnerable to mechanical stress including physical exercise, which is a powerful stimulator of mitogen-activated protein kinases (MAPKs). To examine how treadmill exercise affects MAPK family members in dystrophin-deficient skeletal muscle, we subjected both mdx mice, an animal model for Duchenne muscular dystrophy, and C57BL/10 mice to treadmill exercise  and examined the phosphorylated protein levels of extracellular-signal regulated kinase (ERK1/2), p38 MAPK and c-Jun N terminal kinase 1 and 2 (JNK1 and JNK2) in the gastrocnemius muscle. Phosphorylation of ERK1/2, p38 MAPK and JNK2, but not JNK1, increased more in the muscles of exercise trained mdx mice than in muscles of trained C57BL/10 or untrained mdx mice. These results show that physical exercise aberrantly up-regulates the phosphorylated form of ERK1/2, p38 MAPK and JNK2 in dystrophin-deficient skeletal muscle and that  their up-regulation might play a role in the degeneration and regeneration process of dystrophic features.

 

24/12/04: Increased mRNA expression of tissue inhibitors of metalloproteinase-1 and -2 in Duchenne muscular dystrophy

24/12/04: PTC Therapeutics Initiates a Phase 1 Multiple-Dose Study Of PTC124, An Investigational Drug for Cystic Fibrosis and Duchenne Muscular Dystrophy

22/12/04: Phase I study of dystrophin plasmid-based gene therapy in duchenne/becker muscular dystrophy

22/12/04: (In Press: J. Pediatr. 2005;25:95-7):Should Foot Surgery Be Performed for Children With Duchenne Muscular Dystrophy?

Khristinn Kellie Leitch,, Naweed Raza, Doug Biggar,  Derek Stephen, James G. Wright   and Benjamin Alman -  Canada

Abstract: The authors conducted a retrospective study to determine the outcome of foot surgery in full-time wheelchair users with Duchenne muscular dystrophy. Medical records on all 88 teenaged boys with Duchenne muscular dystrophy treated at the authors’ institution were obtained and reviewed. Patients completed questions about shoe wear, pain, hypersensitivity, and cosmesis, and a foot examination was performed. There were no significant differences between patients who did and did not receive foot surgery with respect to shoe wear (p> . 0.05), pain (p> . 0.05), hypersensitivity (p> . 0.05), or cosmesis (p> . 0.05). Hindfoot motion was significantly better (p> . 0.05) but equinus contracture was significantly worse (p> . 0.05) in patients who had not had surgery.

18/12/04: Systemic delivery of antisense oligoribonucleotide restores dystrophin expression in body-wide skeletal muscles

http://www.pnas.org/cgi/content/abstract/0406700102v1?maxtoshow=&HITS=&hits=&RESULTFORMAT=1&andorexacttitle=and&andorexacttitleabs=and&fulltext=muscular+dystrophy&andorexactfulltext=and&searchid=1103384614512_7179&stored_search=&FIRSTINDEX=0&sortspec=date&fdate=12/1/2004&resourcetype=1

Qi Long Lu, Adam Rabinowitz, Yun Chao Chen , Toshifumi Yokota, HaiFang Yin, Julia Alter, Atif Jadoon , George Bou-Gharios, and Terence Partridge - United Kingdom

Antisense oligonucleotide-mediated alternative splicing has great potential for treatment of Duchenne muscular dystrophy (DMD) caused by mutations within nonessential regions of the dystrophin gene. We have recently shown in the dystrophic mdx mouse that exon 23, bearing a nonsense mutation, can be skipped after intramuscular injection of a specific 2'-O-methyl phosphorothioate antisense oligoribonucleotide (2OMeAO). This skipping created a shortened, but in-frame, transcript that is translated to produce near-normal levels of dystrophin expression. This expression, in turn, led to improved muscle function. However, because DMD affects muscles body-wide, effective treatment requires dystrophin induction ideally in all muscles. Here, we show that systemic delivery of specific 2OMeAOs, together with the triblock copolymer F127, induced dystrophin expression in all skeletal muscles but not in cardiac muscle of the mdx dystrophic mice. The highest dystrophin expression was detected in diaphragm, gastrocnemius, and intercostal muscles. Large numbers of fibers with near-normal level of dystrophin were observed in focal areas. Three injections of 2OMeAOs at weekly intervals enhanced the levels of dystrophin. Dystrophin mRNA lacking the targeted exon 23 remained detectable 2 weeks after injection. No evidence of tissue damage was detected after 2OMeAO and F127 treatment either by serum analysis or histological examination of liver, kidney, lung, and muscles. The simplicity and safety of the antisense protocol provide a realistic prospect for treatment of the majority of DMD mutations. We conclude that a significant therapeutic effect may be achieved by further optimization in dose and regime of administration of antisense oligonucleotide.

17/12/04: (In Press: Brain & Development, 2004):Coagulation system activated in Duchenne muscular dystrophy patients with cardiac dysfunction

Toshio Saito, Yuko Yamamoto, Tsuyoshi Matsumura, Sonoko Nozaki,Harutoshi Fujimura, Susumu Shinno - Japan

Abstract

We investigated basic abnormalities of coagulation and fibrinolysis in Duchenne muscular dystrophy (DMD) patients with cardiac dysfunction. Forty seven patients with DMD, aged 13–37 years old, were enrolled. Based on left ventricular ejection fraction (LVEF) results determined by echocardiography, patients were divided into 3 groups: LVEF less than 30% (markedly depressed group), LVEF between 30 and 50% (slightly depressed), and LVEF greater than 50% (normal). We measured serum levels of total fibrin and fibrinogen degradation products (FDP), as well as plasma fibrinogen, thrombin–antithrombin complex (TAT), prothrombin fragment (F1C2), and D-dimer. The levels of TAT and F1C2 in the markedly depressed group were significantly elevated compared with the other groups, whereas FDP, fibrinogen, and D-dimer levels did not differ among the groups. We concluded that activated coagulation is associated with cardiac dysfunction in patients with DMD.

17/12/04: MUSCULAR DYSTROPHY GENE THERAPY TRIAL PASSES FIRST TEST BY NIH COMMITTEE

17/12/04: Duchenne Muscular Dystrophy: Stalled at the junction?

09/12/04:(In Press: Brain & Development, 2004): A novel approach to identify Duchenne muscular dystrophy patients for aminoglycoside antibiotics therapy

Shigemi Kimura, Kaori Ito, Toshihiko Miyagi, Takashi Hiranuma, Kowasi Yoshioka, Shirou Ozasa, Makoto Matsukura, Makoto Ikezawa, Masafumi Matsuo,Yasuhiro Takeshima, Teruhisa Miike  - Japan

Abstract

Aminoglycoside antibiotics have been found to suppress nonsense mutations located in the defective dystophin gene in mdx mice, suggesting a possible treatment for Duchenne muscular dystrophy (DMD). However, it is very difficult to find patients that are applicable for this therapy, because: (1) only 5-13% of DMD patients have nonsense mutations in the dystrophin gene, (2) it is challenging to find nonsense mutations in the gene because dystrophin cDNA is very long (14 kb), and (3) the efficiency of aminoglycoside-induced read-through is dependent on the kind of nonsense mutation. In order to develop a system for identifying candidates that qualify for aminoglycoside therapy, fibroblasts from nine DMD patients with nonsense mutation of dystrophin gene were isolated, induced to differentiate to myogenic lineage by AdMyoD, and exposed with gentamicin. The dystrophin expression in gentamicin-exposed myotubes was monitored by in vitro dystrophin staining and western blotting analysis. The results showed that gentamicin was able to induce dystrophin expression in the differentiated myotubes by the read-through of the nonsense mutation TGA in the gene; a read-through of the nonsense mutations TAA and TAG did not occur and consequently did not lead to dystrophin expression. Therefore, it is speculated that the aminoglycoside treatment is far more effective for DMD patients that have nonsense mutation TGA than for patients that have nonsense mutation TAA and TAG. In this study, we introduce an easy system to identify patients for this therapy and report for the first time, that dystrophin expression was detected in myotubes of DMD patients using gentamicin.

08/12/04: Study on the recombinant adeno-associated virus vector carrying LacZ gene expression in the skeletal muscle

04/12/04: HSCs for muscular dystrophy: a paradigm shift, back

04/12/04: (In Press: Neuromuscular Disorders, 2004): Report of a Muscular Dystrophy Campaign funded workshop Birmingham, UK, January 16th 2004. Osteoporosis in Duchenne muscular dystrophy; its prevalence, treatment and prevention

R. Quinlivan, H. Roper, M. Davie, N.J. Shaw, J. McDonagh, K. Bushby - UK 

11. Conclusions and recommendations

11.1. DMD and osteoporosis

Duchenne muscular dystrophy leads to reduced mobility, which is associated per se with an increased chance of fractures and reduced bone mineral density. Bone mineral density, especially in the spine is further reduced by longterm steroid treatment. The development of vertebral fractures is dependent upon the cumulative steroid dose and the risk may be very high for those children receiving long-term steroids. The investigation of bone mineral density in children can be problematic and care is needed in the interpretation of data, however, individual children can act as their own controls. DXA scanning can therefore be used to monitor bone mineral density in an individual patient, but there is no clear relationship between a particular Z score and risk of fracture, and DXA results alone should not be used to change practice or lead to specific treatment. When developing randomised controlled treatment trials, different centres may not have compatible DXA machines or software but this can be often overcome using statistical methods for correction.

11.2. Prevention of complications

Fig. 1 is a schematic outline of the proposed management plan agreed by the group. Preserving muscle function will protect long bones, prolonging walking and standing is an important element of management. Sunshine and nutrition are extremely important in maintaining healthy bones and care must be taken to ensure optimal exposure. There is a lack of published evidence for the prevention of vertebral fractures using calcium and vitamin D supplements, there is no evidence based indication to prescribe supplements alongside steroids unless there is a demonstrated deficiency or unless dietary manipulation is not possible.

When commencing steroids in children with DMD, it is prudent to check the 25OH vitamin D levels before treatment. All children should be referred to a dietician in order to optimise the dietary calcium and vitamin D intake. If the 25OH vitamin D levels are low, the clinician may wish to consider treatment with calcium and vitamin D supplements. A baseline DXA scan to assess bone mineral density is probably advisable with follow up scans every 1–2 years, however, at the moment there is no consensus on how to manage worsening bone mineral density in an individual child in the absence of a vertebral fracture. More research is required to establish the long-term effects of bisphosphonates in children, the most effective dose and frequency of treatment, especially oral treatment, before they can be recommended for prophylactic use.

11.3. Treatment of complications

Any patient receiving steroids who complain of back pain should have X-rays (Anterior, Posterior, and Lateral) of the spine taken and if a vertebral fracture is evident urgent referral to a metabolic bone specialist for intravenous bisphosphonate treatment is indicated. Under these circumstances it is not necessary to stop steroid treatment. In the presence of a long bone fracture, a common complication in DMD, no pharmacological treatment is required unless a silent vertebral fracture is discovered on a lateral spine X-ray.

03/12/04: Early onset of lipofuscin accumulation in dystrophin-deficient skeletal muscles of DMD patients and mdx mice

01/12/04: Radiographic and Functional Outcome After Surgical Management of Severe Scoliosis in Skeletally Immature Patients with Muscular Dystrophy

01/12/04: Duchenne muscular dystrophy with associated growth hormone deficiency

01/12/04: Erythrocyte from Duchenne muscular dystrophy is fragile

NOVEMBER/2004

23/11/04:  (Clinicial Nutrition, 2004; 23:1176-1183) Deleteriuos effects of immobilization upon rat skeletal muscle: role of creatine supplementation 

M.S. Aoki, W.P. Lima, E.H. Miyabara, C.H.A. Gouveia, A.S. Moriscot - Brazil

Summary Aim: The aim of the study was to investigate the impact of creatine feeding (5 g kg1 body weight day1) upon the deleterious adaptations in skeletal muscle induced by immobilization. Methods: Male Wistar rats were submitted to hind limb immobilization together with three dietary manipulations: control, supplemented with creatine for 7 days (along with immobilization) and supplemented with creatine for 14 days (7 days before immobilization and together with immobilization). Muscle weight (wet/dry) was determined in the soleus (SOL) and gastrocnemius (GAS). The analysis of lean mass was performed by DEXA and myosin heavy chain (MHC) distribution by SDSPAGE. Results: After 14 days of creatine loading, immobilized SOL and GAS total creatine content were increased by 25% and 18%, respectively. Regardless of dietary manipulation, the immobilization protocol induced a decrease in the weight of SOL and GAS (Po0.001). However, creatine feeding for 14 days minimized mass loss in the SOL and GAS (Po0.05). Our findings also indicate that creatine supplementation maximizes the expected slow-to-fast MHC shift driven by immobilization (Po0.05). Conclusions: Previous creatine supplementation attenuates muscle wasting induced by immobilization. This effect is associated with the increment of intramuscular creatine content.

23/11/04: The prognostic value of pre-operative predicted forced vital capacity in corrective spinal surgery for Duchenne's muscular dystrophy

22/11/04: (Early view: Experimental Cell Research, 2005;302(2):170-179) CAPON expression in skeletal muscle is regulated by position, repair, NOS activity, and dystrophy

Laurent Ségalat, Karine Grisoni, Jonathan Archer, Cinthya Vargas, Anne Bertrand and Judy E. Anderson - France and Canada

Abstract

In skeletal muscle, the localization of nNOS is destabilized in the absence of dystrophin, which impacts muscle function and satellite cell activation. In neurons, the adaptor protein, carboxy-terminal PDZ ligand of nNOS (CAPON), regulates the distribution of neuronal nitric oxide synthase (nNOS), which produces the key signaling molecule nitric oxide (NO). While a CAPON-like gene is known to compensate functionally for a dystrophic phenotype in muscle of Caenorhabditis elegans, CAPON expression has not been reported for mammalian muscle. Here, CAPON expression was identified in mouse muscle using Northern and Western blotting and in situ hybridization in combination with immunostaining for laminin. CAPON RNA was expressed in developing normal and dystrophic muscles near fiber junctions with tendons, and levels increased from 1 to 3 weeks. In regenerating normal muscle and also in dystrophic muscles in the mdx mouse, CAPON transcripts were prominent in satellite cells and new myotubes. Expression of CAPON RNA increased in diaphragm muscle of normal and mdx mice after treatment with L-arginine, the NOS substrate. Both CAPON and utrophin protein levels increased in dystrophic quadriceps muscle after treatment with the steroid deflazacort plus L-arginine, known to reduce the dystrophic phenotype. The identification of CAPON transcripts and protein in mammalian muscle and responses to L-arginine suggest CAPON may have a functional role in stabilizing neuronal NOS in skeletal muscle in the cytoskeletal complex associated with dystrophin/utrophin, with possible applications to therapy for human muscular dystrophy.

20/11/04: Abstract presented on Annual American Society of Anesthesiologists, october

Mivacurium in Children with Duchenne’s Muscular Dystrophy: A Comparison of Onset and Duration of Neuromuscular Block with Children without Neuromuscular Diseases

Joachim Schmidt, Tino Munster, Stefanie Wick, Hubert J. Schmitt - Germany

Introduction: Duchenne’s  muscular dystrophy (DMD), an x-linked recessive disorder, is the most common myopathy seen in the pediatric population. Children afflicted with this disease may require anesthesia for muscle biopsy or orthopedic surgery. Of primary concern in children with this disorder is the choice of the neuromuscular blocking agent. Pharmacodynamic data of non-depolarising neuromuscular blocking agents are scarce 1, 2. Succinylcholine is not recommended due to its adverse side effects. Investigation in DMD children with advanced disease state showed prolonged recovery after a standard dosage of rocuronium 2. The aim of this study was to compare the response to 0,2 mg/kg mivacurium in children with DMD and children without neuromuscular diseases (control-group).

Discussion: The results of the present study demonstrate that the recovery of neuromuscular block following a standard dosage of 0,2 mg/kg mivacurium is significantly prolonged in children with DMD compared to controls. Our results confirm a retrospective study where an increased sensitivity to mivacurium in children with DMD was suggested 4. We therefore recommend the monitoring of the neuromuscular function if mivacurium is used in children with DMD.

20/11/04: ‘MOLECULAR PATCHES’ OR EXON SKIPPING AS A THERAPY FOR DUCHENNE MUSCULAR DYSTROPHY  

18/11/04: (In Press: Molecular Therapy, 2004) Adeno-Associated Virus-Mediated Microdystrophin Expression Protects Young mdx Muscle from Contraction-Induced Injury

Mingju Liu, Yongping Yue, Scott Q. Harper, Robert W. Grange, Jeffrey S. Chamberlain, and Dongsheng Duan - USA

Duchenne muscular dystrophy (DMD) is the most common inherited lethal muscle degenerative disease. Currently there is no cure. Highly abbreviated microdystrophin cDNAs were developed recently for adeno-associated virus (AAV)-mediated DMD gene therapy. Among these, a C-terminaltruncated DR4-R23/DC microgene (DR4/DC) has been considered as a very promising therapeutic candidate gene. In this study, we packaged a CMV.DR4/DC cassette in AAV-5 and evaluated the transduction and muscle contractile profiles in the extensor digitorum longus muscles of young (7- week-old) and adult (9-month-old) mdx mice. At ~3 months post-gene transfer, 50–60% of the total myofibers were transduced in young mdx muscle and the percentage of centrally nucleated myofibers was reduced from ~70% in untreated mdx muscle to ~22% in microdystrophin-treated muscle. Importantly, this level of transduction protected mdx muscle from eccentric contractioninduced damage. In contrast, adult mdx muscle was more resistant to AAV-5 transduction, as only ~30% of the myofibers were transduced at 3 months postinfection. This transduction yielded marginal protection against eccentric contraction-induced injury. The extent of central nucleation was also more difficult to reverse in adult mdx muscle (from ~83% in untreated to ~58% in treated). Finally, we determined that the DR4/DC microdystrophin did not significantly alter the expression pattern of the endogenous full-length dystrophin in normal muscle. Neither did it have any adverse effects on normal muscle morphology or contractility. Taken together, our results suggest that AAVmediated DR4/DC microdystrophin expression represents a promising approach to rescue muscular dystrophy in young mdx skeletal muscle.

14/11/04: Abstracts presented on 14th Meeting of the European Neurological Society - Spain, june/2004:

1) Effect of treatment with PDTC and IRFI 042 on strength and fatigue in MDX mice

S. Messina, P. Seminara, M. Aguennouz, M.C. Monici, H. Marini, F. Squadrito, G. Vita (Messina, I)

Previous studies provided evidences that generation of reactive oxygen species and activation of transcription factor NF-kB may play important roles in the pathogenesis of Duchenne muscular dystrophy. We tested whether IRFI 042, a vitamin E-like antioxidant, and PDTC, a NF-kB inhibitor, could have an effect on muscle weakness in mdx mice. We treated 48 5/6-week old mdx and wild type mice with intraperitoneal injections of PDTC (50 mg/kg), IRFI 042 (20 mg/kg), or vehicle, three times a week for five weeks. Data regarding weight, survival and forelimb strength and fatigue were collected. Motor performance measurements were carried out using a grip meter attached to a force transducer which measures peak force generated. Mdx mice treated with IRFI 042 or PDTC showed at the end of treatment a significantly higher forelimb strength than vehicle controls (IRFI 042: +53.6%, p<0.001; PDTC: +53.1%, p<0.05) as well as higher strength normalised to weight (IRFI 042: +57.8%, p<0.001; PDTC: +54%, p<0.05). Furthermore PDTC-treated mdx mice had significantly less fatigue than vehicle animals (-120%, p<0.004).

Our results suggest that PDTC and IRFI 042 might have a beneficial effect on weakness and fatigue in mdx mice. Further studies are needed to investigate the morphological and biochemical substrates of such encouraging preliminary results.

2) Bone marrow transplantation poorly restores dystrophin expression in MDX mice: comparison of GFP and dystrophin expression

F. Chretien, P.A. Dreyfus, P. Caramelle, B. Chazaud, R.K. Gherardi (Créteil, F)

We have previously developed a murine model of bone marrow (BM) transplantation from B6-TgGFP transgenic mice to normal irradiated B6 mice, the cytoplasmic green fluorescent protein (GFP) being used as an unambiguous marker of donor-derived cells in host muscle. Using this model we were able to demonstrate that stem cell marker-expressing cells found in connective tissue and myogenic precursor cells (satellite cells) may be derived from bone-marrow in adulthood. To investigate the therapeutic potential of BM transplantation in muscle diseases such as dystrophinopathies, we compared the results obtained in C57Bl6 (B6) mice and mdx mice, a model for Duchenne muscular dystrophy in which muscle regeneration is dramatically increased. In mdx muscle compared to B6 muscle, we observed numerous GFP+ mononucleated cells corresponding to macrophages and numerous necrotic fibers filled by GFP+ macrophages and myoblasts. The number of GFP+ satellite cells number was similar in mdx and B6 mice 6 months post transplantation. However, GFP+ muscle fibers were more numerous in mdx mice. They were from month 1 post transplantation, a time point showing no GFP+ fiber in B6 mice. Six months post transplantation, 4 fold more GFP+ muscle fibers were found in mdx mice compared to B6 mice.
In contrast, dystrophin expression was only mildly increased (0,65% at month 6) and colocalizations between GFP and dystrophin was rarely found on serial cross sections. We conclude that the nuclear domain of dystrophin is probably much shorter than that of GFP.

3) Language disorders in Duchenne's muscular dystrophy

F. Civati, M. Guglieri, M.G. D' Angelo, A. Tavano, F. Fabbro, M.L. Lorusso, M. Sironi, A.C. Turconi, G.P. Comi, N. Bresolin (Bosisio Parini, San Vito, Milan, I)

Background: Duchenne Muscular Dystrophy (DMD) is a fatal recessive x-linked muscular disease caused by the absence of dystrophin. Dystrophin isoforms are also expressed in the cerebral neocortex and in the cerebellum. Cognitive impairment is described in 1/3 of DMD patients, particularly in patients carrying deletions in the distal part of the gene. Difficulties in verbal skills and reading abilities are more frequently described in English speaking patients. According to the literature children with DMD show linguistic deficits already in the early phases of language development which mainly consist of poor expressive verbal abilities and deficits in short-term memory. These observations suggest that in some cases dystrophinopathy may be associated to language disorders. Preliminary results in our group of Italian speaking children showed deficit in Grammatical and Syntax Comprehension.
Aims of the study are:
1) to describe the language and reading ability in a group of italian DMD children
2) to clarify the nature of the language and reading deficits
Patients: 13 children with DMD (mean age 8,3 years; standard deviation 1,7) were diagnosed according to international standard criteria. Full Intelligence Quotient(assessed using Wechsler Intelligence Scale) was >70.
Methods: Language and Reading abilities were determined through: “Test dello sviluppo Morfosintattico”, Battery of standardized tests, Battery to evaluate Dyslexia and Dysortography and Tasks of correctness and rapidity. To exclude additional cognitive deficits we evaluated attention/executive functions domain and memory and learning domain thought a Developmental Neuropsychological Assessment (NEPSY particularly: Auditory attention and response set - Visual attention - List learning - Memory for names).
Results: 8 patients out of 13 showed deficit in Syntax Comprehension. 7 patients out of 13 manifested deficits in Grammatical Comprehension. No DMD patients (except one) presented disabilities in reading. Most of the patients showed mild attention and memory deficits.
Discussion: An early identification of the language and eventually attention/memory difficulties, would be important for an early treatment, to support DMD children in their learning course.
 

13/11/04: Antisense oligonucleotides and short interfering RNAs silencing the cyclin-dependent kinase inhibitor p21 improve proliferation of Duchenne muscular dystrophy patients' primary skeletal myoblasts

13/11/04: Naked plasmid DNA for the treatment of muscular dystrophy

13/11/04: Compositional analysis of muscle in boys with Duchenne muscular dystrophy using MR imaging

12/11/04: Duchenne Muscular Dystrophy research focuses on early mechanisms

12/11/04: Key clues to muscle regeneration

12/11/04: RNA Treatment Used to Lower Cholesterol in Mice - RNA Interference can help in DMD

12/11/04: Current concepts in neuromuscular scoliosis

Lee S. Segal - USA

(Current Opinion in Orthopaedics Current Opinion in Orthopaedics 2004, 15:439–446)

Duchenne muscular dystrophy

Sussman provided an excellent overview of the treatment principles for patients with Duchenne muscular dystrophy (DMD) and spinal deformity. The onset of spinal deformity is usually noted between the ages of 11 and 13 years, which corresponds to the time most patients stop walking and become full-time sitters. All children should be screened because scoliosis develops in most patients with this condition. When the scoliosis magnitude reaches 20 to 30°, spine fusion should be done without delay. Nonoperative treatment for scoliosis, such as bracing, is not recommended for patients with DMD. The spine deformity is not responsive to nonsurgical modalities or preventable by them. Posterior spine fusion will not result in marked loss of truncal height or crankshaft deformity, because there is sufficient spinal growth in children with DMD by the time they are 10 or 11 years of age. With progression of the disease, the paraspinal muscles are progressively replaced by stiff fibrofatty tissue. This results in the dissection and exposure of the spine being more difficult, decreases flexibility and the ability to achieve correction, and increases intraoperative blood loss. The most notable complication from delaying surgical stabilization of the spinal deformity is postoperative pulmonary problems. There is a greater risk of postoperative pulmonary problems when the forced vital capacity (FVC) is less than 35%. All patients require full cardiac and pulmonary evaluation preoperatively. Posterior arthrodesis and instrumentation should extend proximally to the upper thoracic spine (T2–T4), ensuring that thoracic kyphosis is maintained and the center of mass of the head is forward. If this is not maintained, patients lose head control because they often lose strength in their neck flexor muscles while retaining strength in their neck extensors. The lower level of fusion distal remains controversial. Some favor ending fusion at L5, and others recommend extending it to the pelvis. Extension to the pelvis, however, increases blood loss, surgical time, and the risk of complications, especially with osteopenia of the pelvis. Sussman noted that patients who undergo stabilization of the spine have improved quality of life, better maintenance of pulmonary function, and a longer life span. Sengupta et al.  evaluated the distal extent of posterior spine fusion in their retrospective series of 50 patients at two different centers. With a minimum follow-up time of 3 years, 31patients underwent fusion to the pelvis and 19 to L5. In these 19 patients, pedicle screws were used in the lumbar spine and sublaminar wires in the thoracic spine. In a comparison of the two groups (pelvic vs L5), the mean age was 14 versus 11.7 years, the mean Cobb angle was 48° versus 20°, the mean pelvic obliquity (PO) was 19.8° versus 9°, the mean estimated blood loss was 4.1L versus 3.3 L, the mean length of stay was 11.7 versus 7.7 days, and the FVC was 44% versus 58%. The PO was corrected and maintained in all but 2 patients with an initial PO greater than 20°. The authors concluded that lumbar instrumentation to L5 is adequate provided that surgery is performed early, soon after the patient becomes wheelchair bound, and with smaller preoperative curves and minimal PO. This selective approach was complemented when surgery was performed in younger patients and with the improvements made in spinal implants and techniques. Pedicle screw fixation into three or more levels achieved a solid distal foundation, allowing the spine to be upright, balanced, and without rotation. This allowed the PO to be corrected and prevented its progression in these patients with a relatively short life expectancy. This paper adds to the growing literature about and controversy over the distal extent of fusion in DMD patients. Mubarak et al.  recommended fusion to L5 when the Cobb angles were less than 40° and the PO was less than 10°. Alman and Kim  noted progression of the PO in 84% (32/38) of patients with lumbar fixation only, but none in the group of patients who underwent fusion to the pelvis. They recommended extending the fusion to the pelvis in general, particularly when the apex of the curve is below L1. However, they did recognize that sublaminar wire fixation may have contributed to the failure of lumbar fixation in controlling PO. In a review paper, Sussman  noted an increased risk of postoperative pulmonary problems when the FVC was less than 35%. In a retrospective series of 30 patients, Marsh et al. evaluated the risks of surgery in patients with low FVC. Of the 30 patients, 13 had a FVC less than 30% of predicted values. The postoperative lengths of stay were similar, and complication rates were comparable to those in other series. The mean length of ventilator support was comparable. The authors emphasized the importance of a multidisciplinary team approach, and they supported the belief that DMD patients with a FVC less than 30% should not be denied posterior spine fusion for scoliosis for pulmonary factors alone. Iannaccone et al.  examined the role of malnutrition in DMD patients undergoing spinal deformity correction. The authors identified nine boys who lost more than 5% of their body weight within 12 months of surgery, and they retrospectively compared this group with eight patients who gained weight after posterior spine fusion and eight patients of comparable age who did not undergo surgery and served as control individuals. The authors noted that weight loss was associated with the loss of self-feeding. This was not associated with loss of biceps strength. Possible factors contributing to this include the decrease in neck range of motion or head control, lack of adequate caregiving, and low cognitive function. One criticism of the paper was that the authors did not evaluate the preservation of thoracic kyphosis. Alman et al.  analyzed the effect of steroid treatment and the development of scoliosis in DMD. The mutation in the dystrophin gene in DMD decreases production of the gene protein important in maintaining the integrity of the cell membrane, and steroids have been shown to maintain the integrity of the cell membrane and decrease the inflammation associated with myocyte cell death. In this nonrandomized prospective cohort study, the authors compared 30 boys (aged 7–10, and still able to walk) treated with deflazacort (a derivative of prednisone with decreased prevalence of side effects) with 24 boys who were not treated (control group). Muscle strength and pulmonary function were evaluated, and the two groups were matched for age and baseline pulmonary function. The patients were monitored for a minimum of 5 years, and Kaplan-Meier analysis was used to determine the risk of the development of scoliosis. Surgery was performed in 15 of 24 patients in the control group and only 5 of 30 in the treated group. This difference between the two groups was statistically significant (P < 0.001). The authors thought that steroid treatment slows the progression of scoliosis, but long-term evaluation is needed to determine whether treatment prevents the development of scoliosis or merely delays its onset. This study supports the hypothesis that the use of corticosteroids improves the natural history in DMD and that the benefits may be even more obvious when treatment is begun earlier in life.

07/11/04: (Early View:Pediatric Research, 2004) Evolving Therapeutic Strategies for Duchenne Muscular Dystrophy: Targeting Downstream Events

JAMES G. TIDBALL  and MICHELLE WEHLING-HENRICKS - USA

E-mail: jtidball@physci.ucla.edu.

Duchenne muscular dystrophy (DMD) is a progressive, lethal, muscle wasting disease that affects 1 of 3500 boys born worldwide. The disease results from mutation of the dystrophin gene that encodes a cytoskeletal protein associated with the muscle cell membrane. Although gene therapy will likely provide the cure for DMD, it remains on the distant horizon, emphasizing the need for more rapid development of palliative treatments that build on improved understanding of the complex pathology of dystrophin deficiency. In this review, we have focused on therapeutic strategies that target downstream events in the pathologic progression of DMD. Much of this work has been developed initially using the dystrophin-deficient mdx mouse to explore basic features of the pathophysiology of dystrophin deficiency and to test potential therapeutic interventions to slow, reverse, or compensate for functional losses that occur in muscular dystrophy. In some cases, the initial findings in the mdx model have led to clinical treatments for DMD boys that have produced improvements in muscle function and quality of life. Many of these investigations have concerned interventions that can affect protein balance in muscle, by inhibiting specific proteases implicated in the DMD pathology, or by providing anabolic factors or depleting catabolic factors that can contribute to muscle wasting. Other investigations have exploited the use of anti-inflammatory agents that can reduce the contribution of leukocytes to promoting secondary damage to dystrophic muscle. A third general strategy is designed to increase the regenerative capacity of dystrophic muscle and thereby help retain functional muscle mass. Each of these general approaches to slowing the pathology of dystrophin deficiency has yielded encouragement and suggests that targeting downstream events in dystrophinopathy can yield worthwhile, functional improvements in DMD.

07/11/04: Effects of stretch-activated channel blockers on [Ca2+]i and muscle damage in the mdx mouse

05/11/2004: Development of an Innovative Technique of Gene Therapy: Exon Skipping

Rescue of Dystrophic Muscle Through U7 snRNA-Mediated Exon Skipping

05/11/2004: Correction of ATM gene function by aminoglycoside-induced read-through of premature termination codons

http://www.pnas.org/cgi/content/abstract/101/44/15676?maxtoshow=&HITS=&hits=&RESULTFORMAT=1&andorexacttitle=and&andorexacttitleabs=and&fulltext=muscular+dystrophy&andorexactfulltext=and&searchid=1099621321093_21896&stored_search=&FIRSTINDEX=0&sortspec=date&fdate=11/1/2004&resourcetype=1

05/11/2004: Tissue Doppler imaging detects early asymptomatic myocardial abnormalities in a dog model of Duchenne's cardiomyopathy

OCTOBER/2004

31/10/04: Researchers make muscular dystrophy breakthrough

31/10/04: Abstracts presented on Annual Meeting of The American Society of Human Genetics (Toronto, Canada - October 26-30/2004)

1) Body-wide delivery of a microdystrophin gene via intravascular administration of rAAV6 vectors for treatment of muscular dystrophy. P. Gregorevic, M. Blankinship, J. Allen, L. Meuse, S. Abmayr, J. Han, J. Chamberlain. Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, Dept. of Neurology, University of Washington, Seattle, WA.

   Severe neuromuscular disorders, such as Duchenne muscular dystrophy (DMD), lead to reduced quality of life and premature mortality. Historically, genetic interventions for these diseases have been limited by an inability to achieve widespread gene transfer to the affected tissues. Here we demonstrate a method that, for the first time, enables transduction of the vast majority of both the cardiac and skeletal musculature of adult mammals via a single intravenous administration of pseudotype 6 recombinant adeno-associated virus (rAAV6) vectors. As a means to enhance gene transfer, we have determined that IV coadministration of vascular endothelium growth factor (VEGF) with rAAV6 vectors can significantly increase vector accumulation and transgene expression in striated muscles. Having established in reporter gene studies that this technique enables tolerable, high-level transgene expression, we sought to evaluate the potential of this technique for delivering a therapeutic transgene to the musculature of the mdx dystrophic mouse, a model of DMD. Using this technique, we have observed that treated mdx mice exhibit expression of microdystrophin throughout the striated musculature in a manner that is sufficient to reduce pathological features of the dystrophic phenotype. Compared with untreated mice, the muscles of treated animals exhibit reduced susceptibility to contraction-induced injury, and reduced serum creatine kinase levels, reflecting a global reduction in muscle degeneration. These data are the first to demonstrate body-wide amelioration of symptoms associated with dystrophin deficiency in an adult animal following a genetic intervention. In subsequent studies we have established that these techniques can be adapted to express alternate transgenes for the treatment of other muscle diseases. We are currently undertaking studies to determine whether the existing techniques are effective in animals more similar in size and immunology to humans, and present relevant data summarizing our progress

2) Therapeutic antisense-induced exon skipping for Duchenne muscular dystrophy. A. Aartsma-Rus1, A. Janson1, G. Platenburg2, M. Bremmer-Bout1, J.T. Den Dunnen1, J.C.T. Van Deutekom1, G-J.B. Van Ommen1. 1) LUMC, Leiden, the Netherlands; 2) Prosensa, Leiden, the Netherlands.

   The severe Duchenne muscular dystrophy (DMD) is mostly caused by frame disrupting mutations in the dystrophin gene, which result in non-functional proteins. Mutations that keep the reading frame intact give rise to internally deleted, semi-functional dystrophins and result in the milder Becker muscular dystrophy (BMD). Antisense oligonucleotides (AONs) have the potential to modulate the pre-mRNA splicing such that a specific exon is skipped. As a result, the reading frame can be restored, which allows the synthesis of a BMD-like dystrophin.
   We have recently demonstrated the skipping of 20 different human DMD exons using 2'-O-methyl RNA AONs with a full-length phosphorothioate backbone (2OMePS), and confirmed the therapeutic applicability of this strategy in cultures from 10 different DMD patients. We now compare the efficacy and efficiency of 2OMePS AONs to morpholino, locked nucleic acid (LNA) and peptide nucleic acid (PNA) AONs. While LNA was most efficient in inducing exon skipping, we find that it acts in a less sequence-specific manner, probably due to its extremely high RNA affinity. Awaiting further improvements in oligochemistry, we therefore consider 2OMePS AONs currently the most favourable compounds.
   To facilitate clinical application, multiple in vivo studies in animal models are ongoing to develop safe and efficient AON-delivery methods. However, as exon skipping is a sequence-specific therapy, it is desirable to directly target the human DMD gene. We have therefore set up sequence-specific human exon skipping in vivo in transgenic mice carrying the an intact copy of the full-length 2.5 Mb human gene (hDMD). We injected 2OMePS AONs targeting human exons 44, 46 and 49 into the m. gastrocnemicus of hDMD mice, and showed skipping of the human (but not the murine) exons, which persisted for at least 28 days. Based on pre-clinical data obtained by our group and others, we are currently setting up a clinical trial aiming at local dystrophin restoration following intramuscular injections of exon 46 and 51 specific AONs.
 

31/10/04: (In Press: Molecular Therapy, 2004) Optimization of Regional Intraarterial Naked DNA-Mediated Transgene Delivery to Skeletal Muscles in a Large Animal Model

Gawiyou Danialou,Alain S. Comtois,Stefan Matecki, Josephine Nalbantoglu, George Karpati, Renald Gilbert, Pascale Geoffroy, Sandra Gilligan, Jean-Francois Tanguay, and Basil J. Petrof - Canada

Effective gene therapy for muscular dystrophy will likely require intravascular administration. Although plasmid DNA (pDNA) contained within a large volume and rapidly infused into a major artery can achieve gene transfer within downstream muscles, this is associated with substantial muscle edema. Here we hypothesized that excessive edema-related increases in intramuscular pressure (IM pressure) developed during intraarterial pDNA injections could hinder successful gene delivery. Accordingly, we monitored IM pressure during injection of pDNA carrying a LacZ transgene into the femoral artery of rats and pigs. Large variations in IM pressure were found between different muscles. There was a significant inverse relationship between IM pressure and the subsequent level of gene transfer to muscle. Modification of the injection protocol to reduce IM pressure led to greatly increased pDNA-mediated gene expression and reduced muscle damage in pigs. Under the most optimized conditions, average transfection within eight different muscles of the pig hind limb amounted to 22% of all fibers, attaining a maximum of 60% in the gastrocnemius muscle. We conclude that IM pressure monitoring is a simple and useful procedure, which can be applied in both small and large animals to help optimize pDNA-mediated gene transfer to skeletal muscles by the intraarterial route.

31/10/04: Targeted expression of insulin-like growth factor-i reduces early myofiber necrosis in dystrophic mdx mice

28/10/04: First cord blood stem cells transplantation in DMD - more informations

Dr. Cheng Zhang answer my questions in this e-mail:

"Dear Dr. David Feder,

 Thank you for your email. Yes, we used a nonrelated cord blood stem cell. Because the HLA match is very well so the immune reaction is not obvious, but we still use some immunossupresor drugs now. We are preparing another boys for transplantation.

Best wishes,

Cheng Zhang"

26/10/04: Stem cell transplantation in DMD - first report in China

This is the answer for Dr. Cheng Zhang about this first procedure in the world:

"Dear Dr. David Feder,

Thank you for your email. Today is 92 days that the DMD boy is transplanted by umbilical cord stem cells. He is twelve years old and he cannot walk for almost three years. The umbilical cord stem cells was transfer into his vein 92 days ago. The muscle biopsy was done after 76 days of the transplantation. We find that the dystrophin staining is weak positive in some muscle cells. We are conforming that the weak positive muscle cells come from the donor. The DMD boy has a little improvement in his locomotive function, for example, he touch his nose a little better than before. Now, the DMD boy is OK, he like watch TV, and sometimes play cards with nurse. We are still waiting and observing what happen on him.

Sincerely yours,

 Cheng Zhang, MD, PhD - Professor and Chair, Department of Neurology

First Affiliated Hospital - Sun Yat-sen University - Guangzhou, Guangdong, 510080

P. R. China"

16/10/04: Comparison of high-capacity and first-generation adenoviral vector gene delivery to murine muscle in utero

14/10/04: (Early View: Blood, 2004) Regional intravascular delivery of AAV-2-F.IX to skeletal muscle achieves longterm correction of hemophilia B in a large animal model

Valder R. Arruda, Hansell H. Stedman, Timothy C. Nichols, Mark E. Haskins, Matthew Nicholson, Roland W. Herzog, Linda B. Couto, Katherine A. High - USA

ABSTRACT

In earlier work, we showed that adeno-associated virus mediated delivery of a Factor IX gene to skeletal muscle by direct intramuscular injection resulted in therapeutic levels of circulating Factor IX in mice. However, achievement of target doses in humans proved impractical because of the large number of injections required. We used a novel intravascular delivery technique to achieve successful transduction of extensive areas of skeletal muscle in a large animal with hemophilia. We provide here the first report of long-term (>3 years, with observation ongoing), robust Factor IX expression (circulating levels of 4-14%) by muscle-directed gene transfer in a large animal, resulting in essentially complete correction of the bleeding disorder in hemophilic dogs. The results of this translational study establish an experimental basis for clinical studies of this delivery method in humans with hemophilia B. These findings also have immediate relevance for gene transfer in patients with muscular dystrophy.

14/10/04: Helpful Informations about  Steroids in DMD

14/10/04: (EMBO reports, 2004; 5(9):872-6) Duchenne muscular dystrophy and dystrophin: pathogenesis and opportunities for treatment

Kristen J.Nowak & Kay E.Davies -  MRC Functional Genetics Unit,University of Oxford,UK

Duchenne muscular dystrophy (DMD) is caused by mutations in the gene that encodes the 427-kDa cytoskeletal protein dystrophin. Increased knowledge of the function of dystrophin and its role in muscle has led to a greater understanding of the pathogenesis of DMD. This, together with advances in the genetic toolkit of the molecular biologist, are leading to many different approaches to treatment. Gene therapy can be achieved using plasmids or viruses, mutations can be corrected using chimaeraplasts and short DNA fragments, exon skipping of mutations can be induced using oligonucleotides and readthrough of nonsense mutations can be achieved using aminoglycoside antibiotics. Blocking the proteasome degradation pathway can stabilize any truncated dystrophin protein, and upregulation of other proteins can also prevent the dystrophic process. Muscle can be repopulated with myoblasts or stem cells. All, or a combination, of these approaches hold great promise for the treatment of this devastating disease.

14/10/04: Muscle ultrasound in children: Normal values and application to neuromuscular disorders

07/10/04: MY FIRST RESEARCH IN MUSCULAR DYSTROPHY - Tamoxifen increases muscular strength of the mdx dystrophic mice

(Abstract from 44th Annual Meeting - American Society for Cell Biology (December, 4-8, 2004, Washington)

A. Cavalsan,1 R. F. Vasquez,1 R. C. Lin,1 S. B. Zyngier,1 F. J. Velloso,2 B. H. Santos,2 L. L. Fogaca,2 M. Vainzof,2 D. Feder1 ; 1 Pharmacology, ABC Faculty of Medicine, Santo Andre, Brazil, 2 Human Genome Research Center - IB USP, Sao Paulo, Brazil

The mdx mice is a well-known model of Xp21 dystrophin-deficient muscular dystrophy. Although a good genetic and biochemical model, the mdx shows no muscle weakness, but under physical exercise, a loss of muscular strength can be detected. Here we have tested the possible therapeutic beneficial effect of Tamoxifen in the degenerative process of the dystrophic muscle, analyzing muscle strength of tamoxifen treated mdx mice, under intensive physical exercise. A total of 22 mices aged 4 weeks were divided into 3 groups: control (n= 8) treated with 0.5 mL saline ip, Tamoxifen 5 mg/Kg body weight ip (n= 8) daily and Tamoxifen 10 mg/Kg ip (n=6) daily. The exercise protocol was done in a wheel revolving at 18 cm/s, for 10 minutes, twice a day, 5 days/week, up to 12 weeks. Whole-body strength was measured weekly using a force transducer coupled to a computer. Mice tails were attached via a non-flexibile nylon cord to the transducer, the animals were electricly stimulated to run, and the force to pull the cord was registered continuously. Results were analyzed by the Kruskal-Wallis test. The mice treated either with 5 mg/Kg (6.26+ 1.44 dynes/g body weight) or 10 mg/Kg (6.46+ 2.52) showed a significant increase of muscular strength (p<0.05) compared to the control group (3.66+ 0.77) starting in the 5th week, and maintaining significance up to the end of the experiment. Histological and histochemical analysis of the complex of the gastrocnemius muscle are under analysis, but preliminary results suggest a less degree of degeneration in the Tamoxifen treated groups.
Tamoxifen is an anti tumoral drug and act on TGF-beta. Its possible therapeutic effect in the degenerative process of the dystrophic muscle could ameliorates the clinical course of dystrophic patients.
FAPESP-CEPID, CNPq, PRONEX, NEPAS-FMABC.

07/10/04: Early view: Abstracts from 44th Annual Meeting - American Society for Cell Biology (December, 4-8, 2004, Washington)

Human Retinal Dystrophin Transgene Converts Lethal Muscular Dystrophy into Viable Mild Myopathy in Dystrophin-Utrophin Null Mice
R. Gaedigk,1,2 D. J. Law,3 K. M. Fitzgerald-Gustafson,4,2 S. G. McNulty,1 N. N. Nsumu,1 A. C. Modrcin,5 R. J. Rinaldi,5 D. Pinson,6 S. C. Fowler,7 M. Bilgen,4,8 J. Burns,9 S. D. Hauschka,10 R. A. White1,2 ; 1 Medical Research, Children's Mercy Hospitals & Clinics, Kansas City, MO, 2 Pediatrics, UMKC School of Medicine, Kansas City, MO, 3 School of Biological Sciences, Univ. of Missouri-Kansas City, Kansas City, MO, 4 Hoglund Brain Imaging Center, Univ. of Kansas Medical Center, Kansas City, KS, 5 Rehabilitation Medicine, Children's Mercy Hospitals & Clinics, Kansas City, MO, 6 Pathology & Laboratory Medicine, Univ. of Kansas Medical Center, Kansas City, KS, 7 Pharmacology & Toxicology, Univ. of Kansas, Lawrence, KS, 8 Molecular & Integrative Physiology, Univ. of Kansas Medical Center, Kansas City, KS, 9 Veterinary Imaging Services, Topeka, KS, 10 Biochemistry, Univ. of Washington, Seattle, WA

Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by severe dystrophin gene mutations that often result in death by the third decade. The mdx mouse is the most commonly used DMD model. Although they lack dystrophin and have underlying muscle disease, mdx mice appear physically normal. This may be partially due to compensatory expression of the dystrophin-related protein, utrophin. In contrast, double mutant mice (DM), deficient for both dystrophin and utrophin (mdx/+, utrn -/-), die by 3 months of age and suffer from severe muscle weakness, pronounced growth retardation, kyphosis, weight loss, slack posture, and immobility (Deconinck et al. (1997) Cell 90: 717-727; Grady et al. (1997) Cell 90: 729-738). These features make them an excellent physiological model for DMD research. The capacity of a naturally occurring isoform, human retinal dystrophin (Dp260), to compensate for the missing muscle isoform Dp427 was tested in DM mice. The expression of this transgene prevents premature death and reduces the severe muscular dystrophy phenotype to a mild myopathy. Electromyography (EMG), histology, radiography, magnetic resonance imaging, and behavior studies show that DM transgenic mice grow normally, have normal spinal curvature and locomotion, and have reduced muscle pathology. EMG and histologic data from transgenic DM mice are typical of mild myopathy, while the DM mice exhibit severe abnormalities commonly seen in human dystrophinopathies. The expression of human Dp260 in DM mice converts a severe and lethal muscular dystrophy into a non-lethal mild myopathy. Muscle-specific expression of Dp260 could have several advantages over other treatments of DMD

Visualization of Ectopic Calcification in mdx Mouse Skeletal Muscle
N. Kikkawa, T. Ohno, M. Shiozuka, R. Matsuda; The Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan

It has been demonstrated that osteogenic differentiation of skeletal muscle cells are induced by osteogenic factors, such as bone morphogenetic proteins, both in vitro and in vivo. Spontaneous ectopic bone formation in vivo has also been reported in, for instance, fibrodysplasia ossificans progressiva, which is a rare bone disorder. Another example of self-generating ectopic calcification has been found in skeletal muscle of mdx mouse, a model of Duchenne muscular dystrophy (DMD).
We observed the ectopic calcification in mdx mouse thigh muscle by using x-ray micro CT-scanner SkyScan-1074, which gives resolution of 22um. The x-ray images were reconstructed into three dimentional visions. Calcifications were found as spicular structures running parallel to the muscle fiber. Paraffin sections of the regions found by X-ray microtomography were Von Kossa stained to confirm calcium deposits. We also detected ectopic calcifications of living mice with mouse-whole-body x-ray CT-scanner of Aloka. No ectopic calcification was observed in skeletal muscle of B10 mouse, which possesses normal dystrophin gene and was used as a negative control.
Calcified regions of mdx mouse thigh did not overlap with the Evans blue-positive areas but corresponded to some of the regenerating areas. Thus, ectopic calcification can be a diagnostic marker of muscle regeneration in mdx mice, and be available to determine the effects of drug or gene therapies.

Muscle Proteoglycan Levels in Duchenne Muscular Dystrophy Differ from Other Muscular Dystrophies
S. Zanotti, E. Canioni, F. Cornelio, L. Morandi, M. Mora; Neuromuscular Diseases and Neuroimmunology, National Neurological Institute C. Besta, Milano, Italy

Biglycan and decorin are small leucine-rich extracellular proteoglycans that interact with several matrix proteins particularly collagens, and also with cytokines whose activity they may modulate. To better understand the role of these proteoglycans in muscle fibrosis in muscular dystrophies, we investigated the expression of their transcripts and proteins in several forms of muscular dystrophy compared to age-matched controls. mRNAs of both proteoglycans were significantly downregulated in Duchenne muscular dystrophy and significantly upregulated in Becker muscular dystrophy, sarcoglycanopathies and dysferlinopathy. By immunohistochemistry, decorin and biglycan were mainly localized in connective tissue and apparently increased with age. Their presence increased in relation to increased fibrosis in all types of dystrophic muscle.
The increase in biglycan and decorin in most muscle diseases indicates a role of these proteoglycans in the extracellular matrix organization. The significant decrease of decorin and biglycan mRNA in DMD distinguishes this disease from the other studied and may be related to the high levels of TGF-beta1 and TNF-alpha found in this disease.

Sex Differences in Muscle Stem Cell Transplantation Efficiency
B. Deasy,1 A. Lu,1 K. Urish,1 J. Tebbets,1 B. Gharaibeh,1 R. Rubin,2 J. Huard1 ; 1 University of Pittsburgh, Pittsburgh, PA, 2 Allegheny General Hospital, Pittsburgh, PA

We previously demonstrated that muscle-derived stem cells (MDSCs) efficiently regenerate skeletal muscle tissue after transplantation into dystrophic mdx mice, which model muscular dystrophy. Here we show that transplantation of female MDSC (F-MDSC) rather than male MDSCs (M-MDSC) significantly improves skeletal muscle regeneration.
We transplanted F-MDSCs into the gastrocnemius muscles of female mdx mice and the same number of M-MDSCs into the gastrocnemius muscles of male mdx mice. We used a previously described protocol to measure the cells’ regeneration index (RI)_the number of dystrophin-positive fibers in the host muscle per 105 donor cells_two weeks after transplantation. The F-MDSCs elicited significantly superior muscle regeneration equivalent to a 6-fold increase in efficiency (F-MDSC RI=686±120 versus M-MDSCs RI=105±25, P< 0.01). Sex-crossed transplantation also demonstrated the same trend for the donor cells. We hypothesize that this difference may be related to reduced ability of the M-MDSC to self-renew or to tolerate hypoxic stress. F-MDSCs maintained CD34 expression (>80% of total cells) for up to 200 population doublings, whereas M-MDSCs exhibited a rapid drop in CD34 expression (from >80% to <30% of total cells) after only 45 population doublings. To support the notion that the F-MDSC are more tolerant to stress, we also found that proliferation of F-MDSC was less affected by low O2 conditions as compared with M-MDSC.
Our discovery of sex-related differences in muscle stem cell biology reveals clear limitations to using male stem and progenitor cells for cell-tracking purposes. This finding also warrants careful consideration by researchers working to identify optimal populations of stem and progenitor cells for use in cell therapy and tissue engineering, clinicians who perform bone marrow stem cell transplantation, and basic scientists investigating cell and developmental biology.

 07/10/04: Effects of prednisone in canine muscular dystrophy

07/10/04: (Early view: Neuromuscular Disorders,2004) Albumin targeting of damaged muscle fibres in the mdx mouse can be monitored by MRI

Helge Amthor, Thomas Egelhof, Iain McKinnell, Mark E. Ladd, Isabelle Janssen,Johannes Weber, Hannsjo¨rg Sinn, Hans-Hermann Schrenk, Michael Forsting, Thomas Voit, Volker Straub - Germany

Increased sarcolemmal permeability has been implicated as a major pathological event in muscular dystrophies. In our study, we evaluated whether damaged muscle fibres can be specifically targeted using albumin as a carrier. We tagged human serum albumin (HSA) with Gadolinium (Gd) and systemically applied this compound (Gd-DTPA-HSA) to wildtype and dystrophin-deficient mdx mice. We performed magnetic resonance imaging before and after intravenous administration of Gd-DTPA-HSA and found localised signal enhancement only in mdx skeletal muscle. We also examined skeletal muscle after contrast enhanced magnetic resonance imaging using anti-human albumin antibodies and demonstrated intracellular accumulation of Gd-DTPA-HSA in clusters of damaged mdx muscle fibres. Comparison of magnetic resonance imaging and histological data emphasised the value of contrast agent enhanced magnetic resonance imaging for the in vivo assessment of fibre damage in muscular dystrophies. Furthermore, our data provide evidence that albumin can be used as a carrier to target covalently bound molecules to degenerating muscle fibres.

01/10/04: Recombinant adeno-associated viral (rAAV) vectors as therapeutic tools for Duchenne muscular dystrophy (DMD)

01/10/04: Glucocorticoid treatment alleviates dystrophic myofiber pathology by activation of the calcineurin/NF-AT pathway

SEPTEMBER/2004

30/09/04: Gender dimorphism influences extracellular matrix expression and regeneration of muscular tissue in mdx dystrophic mice

25/09/04: Bone Marrow Cells Regenerate Heart in Brazil Test

25/09/04: Towards a therapeutic inhibition of dystrophin exon 23 splicing in mdx mouse muscle induced by antisense oligoribonucleotides (splicomers): target sequence optimisation using oligonucleotide arrays

25/09/04: Nonmuscle stem cells fail to significantly contribute to regeneration of normal muscle

23/09/04: (Early View:Muscle and Nerve, 2004): Localization and early time course of TGF-beta 1 mRNA expression in dystrophic muscle

Luc E. Gosselin, PhD, Jacqueline E. Williams, BS, Melissa Deering, MS, Daniel Brazeau, PhD, Stephen Koury, PhD, Daniel A. Martinez, PhD  - USA

Fibrosis is a common pathological feature observed in muscle from patients with Duchenne muscular dystrophy (DMD). In the dystrophic (mdx) mouse model of DMD, the diaphragm is more severely affected than other skeletal muscles. The level of transforming growth factor-beta1 (TGF-beta1), an inflammatory cytokine, is significantly elevated in mdx diaphragm. However, little is known about the onset of TGF-beta1 messenger ribonucleic acid (mRNA) expression, or which cells express the mRNA. In this study, we characterized the location and time course of expression of TGF-beta1 mRNA in diaphragm from mdx mice. TGF-beta 1 mRNA was significantly elevated in mdx diaphragm at 6 and 9 but not 12 weeks of age, and these changes corresponded with changes in type I collagen mRNA and hydroxyproline concentration. Mononucleated cells localized to areas of fiber necrosis highly expressed the TGF-beta1 transcript in mdx diaphragm. Neutralization of TGF-beta 1 by decorin administration resulted in a 40% reduction in the level of diaphragm muscle type I collagen mRNA. These findings support a role for TGF-beta1 during the early stages of fibrogenesis in dystrophic diaphragm muscle. Therapeutic interventions aimed at neutralizing this cytokine may be beneficial in slowing the development of fibrosis in DMD.

 

20/09/04: (In Press: International Journal of Obstetric Anesthesia, 2004) Anaesthetic management during labour of a manifesting carrier of Duchenne muscular dystrophy

M.K. Molyneux  - UK

SUMMARY. We describe the peripartum anaesthetic management of a 36-year-old woman who was a manifesting carrier of Duchenne muscular dystrophy. Duchenne muscular dystrophy is an X-linked recessive disorder affecting young males associated with severe complications during anaesthesia if depolarising neuromuscular blocking drugs and volatile agents are used. A manifesting carrier is a heterozygous female who demonstrates the disease in a milder form than in males. This probably occurs because of skewed X-inactivation. We planned to establish regional anaesthesia should an operation be necessary during labour or delivery and to use propofol total intravenous anaesthesia and rocuronium if general anaesthesia became unavoidable. At 37 weeks, the woman went into spontaneous labour, but fetal distress necessitated caesarean section for which combined spinal-epidural anaesthesia was used.

18/09/04: Antisense Therapeutics: A Promise Waiting to Be Fulfilled

18/09/04: Regenerative capacity of the dystrophic (mdx) diaphragm after induced injury

http://ajpregu.physiology.org/cgi/content/abstract/287/4/R961?maxtoshow=&HITS=&hits=&RESULTFORMAT=1&andorexacttitle=and&andorexacttitleabs=and&fulltext=muscular+dystrophy&andorexactfulltext=and&searchid=1095548972362_10235&stored_search=&FIRSTINDEX=0&sortspec=date&fdate=9/1/2004&resourcetype=1

18/09/04: C-Terminal Truncated Dystrophin Identified in Skeletal Muscle of an Asymptomatic Boy with a Novel Nonsense Mutation of the Dystrophin Gene

18/09/04: (In Press: TRENDS in Molecular Medicine, 2004) New therapies for muscular dystrophy: cautious optimism

Giulio Cossu and Maurilio Sampaolesi - Italy

The quest for a therapy for muscular dystrophy has been the driving force behind the past 40 years of advances in this field. Numerous results, such as the identification of satellite cells and gene mutations that are responsible for most forms of dystrophies, advances in gene transfer and modification technology and, more recently, stem cells, have fueled hopes. However, administering corticosteroids still remains the only effective treatment available. Several recent advances have uncovered a diversity of possible therapeutic approaches, from pharmacological treatments to gene therapy (exonskipping and adeno-associated viruses) and cell therapy with different types of newly identified stem cells. Importantly, a combination of these strategies might greatly enhance the possibility of successful therapy.

15/09/04:'Mighty mouse' helping find ways to prevent osteoporosis

15/09/04: Heregulin ameliorates the dystrophic phenotype in mdx mice

15/09/04: (In Press: Neuromuscular Disorders, 2004) Characteristics of the increase in plasma brain natriuretic peptide level in left ventricular systolic dysfunction, associated with muscular dystrophy in comparison with idiopathic dilated cardiomyopathy

Jun Demachi, Yutaka Kagaya, Jun Watanabe, Masahito Sakuma, Jun Ikeda, Yasunori Kakuta, Iyoko Motoyoshi, Takeshi Kohnosu, Hiroaki Sakuma, Shigeru Shimazaki, Hideaki Sakai, Teiko Kimpara, Toshiaki Takahashi, Kiyoshi Omura, Miho Okada, Hiroshi Saito, Kunio Shirato - Japan

Abstract

To determine whether the plasma brain natriuretic peptide level increases differentially in muscular dystrophy and idiopathic dilated cardiomyopathy, we investigated the plasma brain natriuretic peptide level and echocardiographic parameters in patients with similarly low left ventricular ejection fraction. The plasma brain natriuretic peptide level was lower, and the left ventricular end-diastolic diameter was shorter in the patients with muscular dystrophy than in those with idiopathic dilated cardiomyopathy. The correlation between the plasma brain natriuretic peptide and left ventricular ejection fraction was shifted downward in the patients with muscular dystrophy compared with those with idiopathic dilated cardiomyopathy. Those between the brain natriuretic peptide and left ventricular end-diastolic diameter were superimposable, although the data from the muscular dystrophy patients were located at the shorter left ventricular end-diastolic diameter side. The plasma brain natriuretic peptide level may differentially increase in the two diseases with similar left ventricular systolic dysfunction. Differences in the left ventricular distension and in the physical activity might explain at least partially the different plasma brain natriuretic peptide levels.

15/09/04: Function induced modifications of gene expression: an alternative approach to gene therapy of Duchenne muscular dystrophy

08/09/04: Graffinity Pharmaceuticals AG and MyoContract AG Merge to Form Santhera Pharmaceuticals Ag

08/09/04:Mirus Bio Enters into Research Agreement with Genzyme

AUGUST/2004

29/08/04: (Early view: 34th Annual Meeting of Society for Neuroscience; October/2004, San Diego) FUNCTIONAL AND STRUCTURAL IMPROVEMENTS IN MDX SKELETAL MUSCLE FOLLOWING CHRONIC DAILY ADMINISTRATION OF PYRROLIDINE DITHIOCARBAMATE (PDTC)

C. Carlson, A. Siegel, A. Samadi, S. Vulcanar. - USA

The presence of severe dystrophy in the mdx triangularis sterni (TS) indicates that passive stretch activates pathogenic mechanisms that do not involve generalized increases in resting Ca2+ influx (Carlson et al., Neurobiology of Disease, 14, 229,2003).To test whether nuclear activation of NFkB (Kumar and Boriek, FASEB J., 17,386, 2003) is directly involved in dystrophic pathogenesis, mdx mice were treated daily (29-82 days)with 50 mg/kg PDTC (ip),an antioxidant which inhibits the nuclear activation of NFB by stabilizing cytosolic IkB-a. Western blots indicated that a single dose increased cytosolic IkB-a in mdx diaphragm for at least 5 hrs.Chronically treated mdx mice exhibited modest increases in whole body tension (Carlson and Makiejus, Muscle and Nerve, 13,480,1990),a significant (p<0.05) decrease in fatigue,and small increases in gastrocnemius twitch tension.Untreated mdx TS fibers (5-12 m)had an average RP of -43 mV (+1.4 SE, N=77 fibers)which was less (p<0.001) than that seen in nondystrophic TS fibers (5-17 m,-51 mV + 1.4,N=61).PDTC treated mdx muscle fibers isolated at 8 to 9 months had more obvious striations and an average RP (-52 +1.7 mV,N= 48) that was identical to that seen in nondystrophic TS fibers.Older PDTC treated mdx mice (11-22 m) had significantly improved RPs in both caudal (-41 mV+ 2.8, N=52;p<0.001) and middle (-42 + 2.8 mV, N=44; p<0.05) regions of the TS in comparison to age matched saline-injected mice (caudal: -23 + 2.0 mV, N=93; middle: -34.2 +2.5 mV, N=50).These TS muscles also exhibited an increase in the appearance of healthy intact fibers, particularly in the middle region of the muscle.These results indicate that a stretch-induced inflammatory reaction involving NFkB nuclear activation contributes significantly to dystrophic pathology, and that agents which inhibit the nuclear activation of NFkB should have pronounced value in the treatment of muscular dystrophy

C. Carlson, A. Siegel, A. Samadi, S. Vulcanar. FUNCTIONAL AND STRUCTURAL IMPROVEMENTS IN MDX SKELETAL MUSCLE FOLLOWING CHRONIC DAILY ADMINISTRATION OF PYRROLIDINE DITHIOCARBAMATE (PDTC) Program No. 684.18. 2004 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2004. Online

26/08/04: Hematopoietic stem cell transplantation does not restore dystrophin expression in Duchenne Muscular Dystrophy dogs

26/08/04: (Early view: Muscle and Nerve, 2004):Effects of exercise and steroid on skeletal muscle apoptosis in the mdx mouse

Jeong-Hoon Lim, MD, Dai-Youl Kim, MD, Moon Suk Bang, MD, PhD - Republic of Korea

Abstract: Reports concerning the influence of exercise loading and steroid administration on dystrophinopathy are inconsistent. To investigate the effect of muscle exercise in Duchenne muscular dystrophy (DMD), 15 control and 15 mdx mice, an animal model of DMD, were divided into free-living (n = 6), exercise (n = 6), and immobilization (n = 3) groups. Free- living and exercise groups were further divided into steroid- treated and sham-treated groups to evaluate the effect of steroid administration. We measured apoptotic changes by in
situ DNA nick-end labeling (TUNEL), DNA fragmentation assay, and Western blotting for Bcl-2 and BAX. Apoptosis was most prominent in the sham-treated exercise group, and it was significantly reduced in the steroid-treated exercise group. The steroid-treated free-living group showed a higher rate of apoptotic change than the sham-treated free-living group. Apoptosis was minimized in the free-living condition, whereas exercise loading and immobilization caused apoptotic change in this muscular dystrophy animal model. Steroid administration induced apoptosis in muscle of free-living mice, but alleviated the apoptotic damage caused by exercise loading in mdx mice. These findings suggest that steroid administration may be effective in preventing a postexercise deterioration of skeletal muscle in animal models of DMD. 

26/08/04: (IN PRESS: Muscle and Nerve, 30:295-304, 2004): ADMINISTRATION OF INSULIN-LIKE GROWTH FACTOR-I IMPROVES FATIGUE RESISTANCE OF SKELETAL MUSCLES FROM DYSTROPHIC mdx MICE

PAUL GREGOREVIC, , DAVID R. PLANT, , and GORDON S. LYNCH, - Australia

ABSTRACT: Muscle fatigue occurs in many neuromuscular diseases, including the muscular dystrophies, and it contributes to a loss of functional capacity and reduced quality of life for affected patients. An improvement in fatigue resistance has been observed in diaphragm muscles of mdx mice following insulin-like growth factor-I (IGF-I) administration. Whether similar treatment can improve locomotor muscle function in mdx mice is not known. We examined the ef.cacy of IGF-I administration (1 mg/kg daily s.c. for 8 weeks) on structural, metabolic, and functional properties of extensor digitorum longus (EDL) and soleus muscles of mdx mice, and tested the hypothesis that IGF-I treatment would improve function in these muscles. After treatment, muscles were more resistant to fatigue during repeated maximal contractions than muscles from untreated mice, an improvement associated with increased muscle .ber succinate dehydrogenase activity in the absence of changes in cellular (single-.ber) contractile activation characteristics. The .ndings have important clinical implications, not just for the dystrophinopathies, but for all neuromuscular pathologies where fatigue of locomotor muscles limits functional capacity and decreases quality of life.

26/08/04: (IN PRESS: Transplantation, 2004) SUMMARY: IMMUNE PARAMETERS IN THREE DUCHENNE MUSCULAR DYSTROPHY PATIENTS FOLLOWING INTRAMUSCULAR TRANSPLANTATION OF NORMAL MYOGENIC CELLS UNDER FK506 IMMUNOSUPPRESSION.

D. Skuk, R. Roy, B. Roy, M. Goulet, F.J. Dugre´, J.P.Tremblay - Canada

Aims: To test the efficacy of FK506 immunosuppression to control acute rejection in the context of myoblast allotransplantation in Duchenne muscular dystrophy (DMD) patients. Methods: Three DMD patients received injections of myoblasts obtained from skeletal muscle biopsies of normal donors. The cells (30 x 106) were injected in 1 cm3 of the Tibialis anterior by 25 parallel injections. Similar patterns of saline injections were performed in the contralateral muscles. The patients received FK506 for immunosuppression, the doses being adjusted to maintain a blood concentration between 8 to 20 ug/L. Periodical monitoring of the patients included weight, hemogram, glycemia, lipid profile and serum levels of creatinine, urea, sodium, potassium and chlorides. Patients 1 and 2 were previously taking deflazacort to delay the progression of the disease and we maintained this treatment during the study. Muscle biopsies were performed at the injected sites 4 weeks later. Histological studies were done to analyze the success of the graft, and to characterize the immune cells present in the tissue. RT-PCR analysis of the biopsies were done to observe the expression of INFgamma, TNF-alpha, granzyme B, IL-6 and FasL. The presence of antibodies against the donor cells in blood samples taken before and at 2, 4 and 8 weeks after cell transplantation was analyzed by cytofluorometry. Results: We observed dystrophin-positive myofibers in the cellgrafted sites of the three patients: 9 % (patient 1), 6.8 % (patient 2), and 11 % (patient 3). Since patients 1 and 2 had identified dystrophin-gene deletions, these results were obtained using monoclonal antibodies specifically to the deleted exons. The grafted site exhibited some pockets of leukocyte infiltration composed of macrophages and CD4 and CD8 lymphocytes in patient 1. In patient 2, similar leukocyte infiltrations were smaller and scarce. No leukocyte accumulations were observed in patient 3. No antibodies against the donor-cells and the donor MHC class-I and class II were detected in the 3 cases. Only the IL-6 mRNA was significantly increased in one grafted site (patient 1). The only potential side effect of the immunosuppression was some weight increase in patient 3. Conclusions: Significant dystrophin expression can be obtained in the skeletal muscles of DMD patients following specific conditions of cell delivery and immunosuppression. Only the presence of some macrophage/T-lymphocyte accumulations in the vicinity of dystrophin-positive myofibers, and an increase in IL-6 expression could suggest to a moderate, non-completely controlled cellular acute rejection in patient 1. For the rest, the immunosuppression seems quite appropriate. Since patients 1 and 2 received chronic corticosteroid therapy, an additive effect of this treatment on the FK506-based immunosuppression is perhaps possible. The long-term benefit of a FK506-based immunosuppression for myoblast transplantation in DMD patients remains to be tested.

24/08/04: (IN PRESS: Molecular Therapy, 2004) Sustained Muscle Expression of Dystrophin from a High-Capacity Adenoviral Vector with Systemic Gene Transfer of T Cell Costimulatory Blockade

Zhilong Jiang, Gudrun Schiedner, Nico van Rooijen, Chau-Ching Liu, Stefan Kochanek, and Paula R. Clemens - USA

Adenoviral vector (Ad)-mediated gene delivery of normal, full-length dystrophin to skeletal muscle provides a promising strategy for the treatment of Duchenne muscular dystrophy (DMD). However, cellular and humoral immune responses induced by vector gene transfer limit the application of this approach. Blockade of the costimulatory interaction between naRve T cells and antigen-presenting cells has proven to be a successful means to diminish immunity induced by gene transfer. In this study we explore the potential of supplementing dystrophin gene delivery to dystrophin-deficient Dmd mouse skeletal muscle with systemic gene delivery of CTLA4Ig and CD40Ig molecules to effect costimulatory blockade. We found that systemic administration of a high-capacity Ad (HC-Ad) vector carrying murine CTLA4Ig (AdmCTLA4Ig) either alone or codelivered with an HC-Ad vector carrying murine CD40Ig (AdmCD40Ig) provided sustained expression of recombinant full-length murine dystrophin from an HC-Ad vector carrying the dystrophin cDNA (AdmDys). The level of AdmDys vector genomes remained stable in animals cotreated with systemic delivery of vectors carrying molecules to block costimulation. In addition, muscle CD4+ and CD8+ T cell infiltrates and Th1 cytokine production by splenocytes were reduced. The production of neutralizing antibody against Ad vector was significantly inhibited in mice receiving systemic codelivery of both AdmCTLA4Ig and AdmCD40Ig, but not in the mice treated with AdmCTLA4Ig alone. The results suggested that coblockade of both CD28/B7 and CD40L/CD40 costimulatory pathways is required for effective inhibition of the Ad vector-induced humoral immune response in Dmd mice, whereas blockade of CD28/B7 alone by murine CTLA4Ig would be sufficient for prolonged dystrophin expression in treated muscle.

24/08/04: Marathoning Mice Could Have Olympian Effects on Obesity

Research group unveils genetically-engineered mice

24/08/04: (IN PRESS: Neurobiology of Disease, 2004) The alteration of calcium homeostasis in adult dystrophic mdx muscle fibers is worsened by a chronic exercise in vivo

Bodvael Fraysse, Antonella Liantonio, Michela Cetrone,Rosa Burdi, Sabata Pierno, Antonio Frigeri, Michela Pisoni,Claudia Camerino, and Annamaria De Lucaa - Italy

Chronic exercise in vivo aggravates dystrophy in mdx mice. Calcium homeostasis was evaluated ex vivo by micro-spectrofluorometry on tendon-to-tendon dissected extensor digitorum longus (EDL) muscle fibers. Resting cytosolic calcium ([Ca2+]i) and sarcolemmal permeability through Gd3+-sensitive mechanosensitive calcium (MsCa) channel were significantly higher in mdx vs. wild-type fibers. The exercise further enhanced [Ca2+]i in mdx fibers and increased sarcolemmal permeability by activating nifedipine-sensitive leak calcium channels. The two genotypes did not differ in caffeine sensitivity and in the excitation-calcium release (ECaR) coupling mechanism by K+ depolarization. The exercise produced a similar adaptation of activation curve of ECaR and of sensitivity to caffeine. However, the inactivation of ECaR of mdx fibers did not adapt to exercise. No fiber phenotype transition occurred in exercised muscle. We provide the first evidence that an in vivo exercise worsens the impaired calcium homeostasis of dystrophic fibers, supporting the role of enhanced calcium entrance in dystrophic progression.

21/08/04: (IN PRESS: Molecular Therapy, 2004) AAV Vector-Mediated Microdystrophin Expression in a Relatively Small Percentage of mdx Myofibers Improved the mdx Phenotype

Madoka Yoshimura, Miki Sakamoto, Madoka Ikemoto, Yasushi Mochizuki, Katsutoshi Yuasa, Yuko Miyagoe-Suzuki, and Shin’ichi Takeda - Japan

Duchenne muscular dystrophy (DMD) is a lethal disorder of skeletal muscle caused by mutations in the dystrophin gene. Adeno-associated virus (AAV) vector-mediated gene therapy is a promising approach to the disease. Although a rod-truncated microdystrophin gene has been proven to ameliorate dystrophic phenotypes, the level of microdystrophin expression required for effective gene therapy by an AAV vector has not been determined yet. Here, we constructed a recombinant AAV type 2 vector, AAV2-MCKDCS1, expressing microdystrophin (DCS1) under the control of a muscle-specific MCK promoter and injected it into TA muscles of 10-day-old and 5-week-old mdx mice. AAV2-MCKDCS1-mediated gene transfer into 5-week-old mdx muscle resulted in extensive and long-term expression of microdystrophin and significantly improved force generation. Interestingly, 10-day-old injected muscle expressed microdystrophin in a limited number of myofibers but showed hypertrophy of microdystrophin-positive muscle fibers and considerable recovery of contractile force. Thus, we concluded that AAV2-MCKDCS1 could be a powerful tool for gene therapy of DMD.

21/08/04:Chimeric RNA/Ethylene-Bridged Nucleic Acids Promote Dystrophin Expression in Myocytes of Duchenne Muscular Dystrophy by Inducing Skipping of the Nonsense Mutation-Encoding Exon

21/08/04: Intraarterial Delivery of Naked Plasmid DNA Expressing Full-Length Mouse Dystrophin in the mdx Mouse Model of Duchenne Muscular Dystrophy

20/08/04: Blood loss in pediatric spine surgery

More information about blood loss in DMD spine surgery

This article reviews the extent of blood loss in spine surgery for scoliosis corrections in the pediatric age group. An extensive literature review presents blood loss values in surgery for adolescent idiopathic scoliosis, cerebral palsy, Duchenne muscular dystrophy, spinal muscular atrophy, and myelomeningocoele. The underlying disorder plays a major role in determining the extent of blood loss. Blood loss is considerably higher in those patients with a neuromuscular scoliosis compared with adolescent idiopathic scoliosis. Within the neuromuscular group those with Duchenne muscular dystrophy demonstrate the highest mean levels of blood loss. Blood loss is also shown to be progressively greater with increasing numbers of vertebral levels incorporated into the fusion, with posterior fusions compared to anterior fusions, and in those patients having both anterior and posterior fusions

19/08/04: Newly discovered protein may be key to muscular dystrophy

(IN PRESS: Nature, 2004) SNF-6 is an acetylcholine transporter interacting with the dystrophin complex in Caenorhabditis elegans

Hongkyun Kim, Matthew J. Rogers, Janet E. Richmond & Steven L. McIntire - USA

Muscular dystrophies are among the most common human genetic diseases and are characterized by progressive muscle degeneration. Muscular dystrophies result from genetic defects in components of the dystrophin–glycoprotein complex (DGC), a multimeric complex found in the muscle cell plasma membrane. The DGC links the intracellular cytoskeleton to the extracellular matrix and is thought to be important for maintaining the mechanical integrity of muscles and organizing signalling molecules. The exact role of the DGC in the pathogenesis of disease has, however, remained uncertain. Mutations in Caenorhabditis elegans DGC genes lead to specific defects in coordinated movement and can also cause muscle degeneration. Here we show that mutations in the gene snf-6 result in phenotypes indistinguishable from those of the DGC mutants, and that snf-6 encodes a novel acetylcholine/choline transporter. SNF-6 mediates the uptake of acetylcholine at neuromuscular junctions during periods of increased synaptic activity. SNF-6 also interacts with the DGC, and mutations in DGC genes cause a loss of SNF-6 at neuromuscular junctions. Improper clearing of acetylcholine and prolonged excitation of muscles might contribute to the pathogenesis of muscular dystrophies.

17/08/04: (In Press: Molecular Therapy, 2004) Nucleofection of Muscle-Derived Stem Cells and Myoblasts with C31 Integrase: Stable Expression of a Full-Length-Dystrophin Fusion Gene by Human Myoblasts

Simon P. Quenneville,Pierre Chapdelaine,JoJl Rousseau, Jean Beaulieu, Nicolas J. Caron, Daniel Skuk, Philippe Mills, Eric C. Olivares, Michele P. Calos, and Jacques P. Tremblay - Canada

Ex vivo gene therapy offers a potential treatment for Duchenne muscular dystrophy by transfection of the dystrophin gene into the patient’s own myogenic precursor cells, followed by transplantation. We used nucleofection to introduce DNA plasmids coding for enhanced green fluorescent protein (eGFP) or eGFP-dystrophin fusion protein and the phage C31 integrase into myogenic cells and to integrate these genes into a limited number of sites in the genome. Using a plasmid expressing eGFP, we transfected 50% of a mouse muscle-derived stem cell line and 60% of normal human myoblasts. Co-nucleofection of a plasmid expressing the C31 integrase and an eGFP expression plasmid containing an attB sequence produced 15 times more frequent stable expression, because of site-specific integration of the transgene. Co-nucleofection of the C31 integrase plasmid and a large plasmid containing the attB sequence and the gene for an eGFP–full-length dystrophin fusion protein produced fluorescent human myoblasts that were able to form more intensely fluorescent myotubes after 1 month of culture. A nonviral approach combining nucleofection and the C31 integrase may eventually permit safe autotransplantation of genetically modified cells to patients.

13/08/04: Respiratory Care of the Patient with Duchenne Muscular Dystrophy - ATS Consensus Statement

03/08/04: 2004 PPMD Annual Conference Powerpoint Presentations

02/08/04: ( Molecular Therapy. 2004,10(2):386-398) A Facile Nonviral Method for Delivering Genes and siRNAs to Skeletal Muscle of Mammalian Limbs

James E. Hagstrom, Julia Hegge, Guofeng Zhang, Mark Noble, Vladimir Budker, David L. Lewis, Hans Herweijer and Jon A. Wolff  - USA
 

Abstract

Delivery is increasingly being recognized as the critical hurdle holding back the tremendous promise of nucleic acid-based therapies that include gene therapy and more recently siRNA-based therapeutics. While numerous candidate genes (and siRNA sequences) with therapeutic potential have been identified, their utility has not yet been realized because of inefficient and/or unsafe delivery technologies. We now describe an intravascular, nonviral methodology that enables efficient and repeatable delivery of nucleic acids to muscle cells (myofibers) throughout the limb muscles of mammals. The procedure involves the injection of naked plasmid DNA or siRNA into a distal vein of a limb that is transiently isolated by a tourniquet or blood pressure cuff. Nucleic acid delivery to myofibers is facilitated by its rapid injection in sufficient volume to enable extravasation of the nucleic acid solution into muscle tissue. High levels of transgene expression in skeletal muscle were achieved in both small and large animals with minimal toxicity. Evidence of siRNA delivery to limb muscle was also obtained. The simplicity, effectiveness, and safety of the procedure make this methodology well suited to limb muscle gene therapy applications.

02/08/04:( Molecular Therapy. 2004,10(2):232-40) Targeted Exon Skipping in Transgenic hDMD Mice: A Model for Direct Preclinical Screening of Human-Specific Antisense Oligonucleotides

Mattie Bremmer-Bout, Annemieke Aartsma-Rus, Emile J. de Meijer, Wendy E. Kaman, Anneke A. M. Janson, Rolf H. A. M. Vossen, Gert-Jan B. van Ommen, Johan T. den Dunnen and Judith C. T. van Deutekom  - The Netherlands

Abstract

The therapeutic potential of frame-restoring exon skipping by antisense oligonucleotides (AONs) has recently been demonstrated in cultured muscle cells from a series of Duchenne muscular dystrophy (DMD) patients. To facilitate clinical application, in vivo studies in animal models are required to develop safe and efficient AON-delivery methods. However, since exon skipping is a sequence-specific therapy, it is desirable to target the human DMD gene directly. We therefore set up human sequence-specific exon skipping in transgenic mice carrying the full-size human gene (hDMD). We initially compared the efficiency and toxicity of intramuscular AON injections using different delivery reagents in wild-type mice. At a dose of 3.6 nmol AON and using polyethylenimine, the skipping levels accumulated up to 3% in the second week postinjection and lasted for 4 weeks. We observed a correlation of this long-term effect with the intramuscular persistence of the AON. In regenerating myofibers higher efficiencies (up to 9%) could be obtained. Finally, using the optimized protocols in hDMD mice, we were able to induce the specific skipping of human DMD exons without affecting the endogenous mouse gene. These data highlight the high sequence specificity of this therapy and present the hDMD mouse as a unique model to optimize human-specific exon skipping in vivo.

JULY/2004

29/07/04: (In Press: Neuromuscular Disorders, 2004) Prednisolone decreases cellular adhesion molecules required for inflammatory cell infiltration in dystrophin-deficient skeletal muscle

Michelle Wehling-Henricks, James J. Lee and James G. Tidball - USA

Abstract

The mechanism of prednisolone's efficacy in the dystrophic pathology is unclear. Prednisolone's anti-inflammatory functions may be particularly important considering the significance of inflammatory cells in dystrophinopathy. In other pathologies, prednisolone's anti-inflammatory effects can be mediated by reducing cellular adhesion molecule (CAM) expression. The goal of this study was to examine the effects of prednisolone on inflammation and CAM expression in dystrophic muscle. Dystrophin-deficient, mdx mice were treated with 0.75 mg/kg prednisolone from 2 to 4 weeks of age. Prednisolone reduced macrophages (−59%, −57%), CD4+ T-cells (−50%, −60%), CD8+ T-cells (−58%, −48%), and eosinophils (−36%, −25%) in quadriceps and soleus muscles, respectively. Prednisolone-treated mice also exhibited decreased vascular P-selectin (−82%) and ICAM-1 (−52%) expression and fewer L-selectin (−79%) and ICAM-1 (−57%) expressing mononuclear cells in quadriceps. Prednisolone reduced sarcolemmal damage and degeneration as well. Our data show that prednisolone is an effective anti-inflammatory in dystrophic muscle and may function by modulating CAM expression.

28/07/04: Respiratory Care of the Patient With Neuromuscular Weakness: The (not so) New Paradigm

28/07/04: Powerpoint presentations (in PDF format) from Katie Bushby (http://www.parentprojectmd.org/news/latest/index.html):

General Principles of Management in DMD

Steroids — Speaking the Same Language


28/07/04: (In Press: Neuromuscular Disorders, 2004) Deflazacort in Duchenne muscular dystrophy: a comparison of two different protocols

W. D. Biggar L. Politano, V. A. Harris, L. Passamano, J. Vajsar, B. Alman, A. Palladino, L. I. Comi and G. Nigro  - Canada and Italy

Abstract

We compare the long-term benefits and side effects of deflazacort using two treatment protocols from Naples (N) and Toronto (T). Boys with Duchenne muscular dystrophy between the ages of 8 and 15 years and who had four or more years of deflazacort treatment were reviewed. Diagnostic criteria included males with proximal muscle weakness evident before 5 years, increased serum creatine kinase and genetic testing and/or a muscle biopsy consistent with Duchenne muscular dystrophy. Thirty-seven boys were treated with protocol-N using deflazacort at a dose of 0.6 mg/kg per day for the first 20 days of the month and no deflazacort for the remainder of the month. Boys with osteoporosis received daily vitamin D and calcium. Deflazacort treatment started between 4 and 8 years of age. Thirty-two were treated with protocol-T using deflazacort at a dose of 0.9 mg/kg per day, plus daily vitamin D and calcium. Treatment started between 6 and 8 years of age. All boys were monitored every 4–6 months. The results were compared with age-matched controls in the two groups (19 for protocol-N and 30 for protocol-T). For the boys treated with protocol-N, 97% were ambulatory at 9 years (control, 22%), 35% at 12 years (control, 0%), 25% at 15 years (control, 0%). For the 32 boys treated with protocol-T, 100% were ambulatory at 9 years (control, 48%), 83% at 12 years (control, 0%) and 77% at 15 years (control, 0%). No aids or leg braces were used for ambulation. In boys 13 years and older, a scoliosis of >20° developed in 30% of the boys on protocol-N, 16% on protocol-T and 90% of controls. For protocol-N, no cataracts were observed while in protocol-T, 30% of boys had asymptomatic cataracts that required no treatment. Fractures occurred in 19% (control 16%) of boys on protocol-N and 16% (control, 20%) of boys on protocol-T. This report illustrates: (a) the importance of collaborative studies in developing treatment protocols in Duchenne muscular dystrophy and (b) the long-term beneficial effects of deflazacort treatment in both protocols. However, the protocol-T seems to be more effective and frequently is associated with asymptomatic cataracts.

27/07/04: Prednisolone therapy in Duchenne muscular dystrophy prolongs ambulation and prevents scoliosis

25/07/04: Systemic delivery of genes to striated muscles using adeno-associated viral vectors

Gene therapy reaches muscles throughout the body and reverses muscular dystrophy in animal model

Gene Therapy Reverses Muscular Dystrophy in Animal Model

 

23/07/04: Anesthetic Implications of Neuromuscular Disease

Edwards D. Briggs  and Jeffrey R. Kirschy -USA

(J Anesth, 17:177–185, 2003)

Even in healthy patients neuromuscular blocking agents must be administered and monitored with great vigilance to ensure that adverse drug interactions do not occur and that residual postanesthetic muscle paralysis is prevented. The use of muscle relaxants in patients with neuromuscular disease presents several additional potential hazards. The current article addresses the anesthetic implications of some of the more common neuromuscular diseases, including multiple sclerosis, myasthenia gravis, muscular dystrophy, critical illness polyneuropathy, spinal cord injury, and Guillain-Barré syndrome. When caring for patients with these conditions, the anesthesiologist must perform a thorough preoperative assessment, select an appropriate anesthetic technique and muscle relaxant (if needed), and provide careful monitoring of both hemodynamic parameters and the extent of neuromuscular blockade.

Comment by Jason Gregory and Kathryn E. McGoldrick, (Survey of Anesthesiology Volume 48, Number 4, August 2004)

Duchenne muscular dystrophy patients have a high incidence of cardiac abnormalities and often eventually develop a dilated cardiomyopathy that is frequently associated with mitral valve incompetence. Dysrhythmias and cardiac conduction defects are common. Respiratory compromise secondary to scoliosis is another major challenge complicating anesthetic management. Cardiac arrest owing to succinylcholine-induced hyperkalemia has been well documented. Muscular dystrophic patients are sensitive to nondepolarizing neuromuscular blocking agents, but these drugs can be used safely if their effects are properly monitored. Given the known association of Duchenne muscular dystrophy with malignant hyperthermia, the use of triggering agents should be avoided in patients with this condition.

23/07/04: (In Press: Molecular Therapy, 2004) Factors Influencing the Efficacy, Longevity, and Safety of Electroporation-Assisted Plasmid-Based Gene Transfer into Mouse Muscles

Maria J. Molnar, Rénald Gilbert, Yifan Lu,  An-Bang Liu, Athena Guo, Nancy Larochelle, Kristian Orlopp, Hanns Lochmuller,  Basil J. Petrof, Josephine Nalbantoglu, and George Karpati  - Canada

Intramuscular injection of plasmid is a potential alternative to viral vectors for the transfer of therapeutic genes into skeletal muscle fibers. The low efficiency of plasmid-based gene transfer can be enhanced by electroporation (EP) coupled with the intramuscular application of hyaluronidase. We have investigated several factors that can influence the efficiency of plasmid-based gene transfer. These factors include electrical parameters of EP, optimal use of hyaluronidase, age and strain of the host, and plasmid size. Muscles of very young and mature normal, mdx, and immunodeficient mice were injected with plasmids expressing B-galactosidase, microdystrophin, full-length dystrophin, or full-length utrophin. Transfection efficiency, muscle fiber damage, and duration of transgene expression were analyzed. The best transfection level with the least collateral damage was attained at 175–200 V/cm. Pretreatment with hyaluronidase markedly increased transduction, which was also influenced by the plasmid size and the strain and the age of the mice. Even in immunodeficient mice, there was a significant late decline in transgene expression and plasmid DNA copies, although both still remained relatively high after 1 year. Thus, properly optimized EP-assisted plasmid-based gene transfer is a feasible, efficient, and safe method of gene replacement therapy for dystrophin deficiency of muscle but readministration may be necessary.

23/07/04: CTLA4Ig delivered by high-capacity adenoviral vector induces stable expression of dystrophin in mdx mouse muscle

23/07/04: Novel Duchenne Muscular Dystrophy Treatment Through Myoblast Transplantation Tolerance with Anti-CD45RB, Anti-CD154 and Mixed Chimerism

23/07/04: Dystrophin and utrophin expression in muscle tissues of DMD mouse model after transplantation treatment by bone marrow mesenchymal stem cells  

22/07/04: MDA AWARDS BIOTECH COMPANY $1.6 MILLION TO DEVELOP GENE THERAPY FOR MUSCULAR DYSTROPHY


19/07/04: (In Press: Neuromuscular Disorders, 2004) Report on the 124th ENMC International Workshop. Treatment of Duchenne muscular dystrophy: defining the gold standards of management. 2–4 April 2004, Naarden, The Netherlands

K. Bushbya, F. Muntonib, A. Urtizbereac, R. Hughesd, R. Griggse

About steroids:

Adnan Manzur (UK), co-author of the Cochrane report on the use of glucocorticosteroids in DMD described the major findings of this systematic review . Only five randomised controlled trials of the use of steroids in DMD were published in sufficient detail to be able to be included in the review. These trials did, however, present evidence that use of daily prednisolone (0.75 mg/kg per day) or deflazacort (0.9 mg/kg per day) increased strength in DMD. Robert Griggs, Richard Moxley (USA) and Doug Biggar (Canada) were able to confirm that long-term follow up of cohorts of patients treated under one or other of these regimes and who mostly continued using steroids beyond the loss of independent ambulation shows that this increase in strength is mirrored by improvement in function (with age at loss of ambulation in the mid teens, preservation of respiratory function, lack of need for scoliosis surgery and possibly preservation of cardiac function). With longterm use of steroids, the per kilogram dose of corticosteroid tended to reduce with time. In some cases, this was in response to side effects such as weight gain or behaviour changes, but in the majority represented a tendency not to keep up strictly with change in weight over time. Many different regimes for giving steroids in DMD have been suggested as a way to reduce the risk of the wellknown side effects associated with the long-term use of daily steroids. The dose of 0.75 mg/kg per day was shown to be the most effective dose in the early randomised controlled trials, where dose response analysis showed that 0.35 mg/kg per day was not as effective as 0.75 mg/kg per day, while 1.2 mg/kg per day gave no additional benefit . Deflazacort 0.9 mg/kg per day is said to be the equivalent dose to 0.75 mg/kg per day of prednisolone, and appears to be equally as effective. Side effect profiles of the two regimes may differ slightly. Deflazacort appears to cause less weight gain, but is more likely to be associated with the development of asymptomatic cataracts. It is hard to assess the long-term differences in these regimes with respect to their effect on bone mineral density. Some studies have reported a high incidence of vertebral fractures with deflazacort, while other centres have not had this experience. By far the most commonly reported side effects in the published series have been weight gain and behavioural changes. There are known to be many other possible side effects of long-term daily steroid use. These include adrenal suppression, susceptibility to infection, hypertension, impaired glucose tolerance, gastrointestinal irritation and skin fragility. None of the centres with long-term experience in the use of steroids in DMD represented at the meeting had seen these complications at a high frequency. Concern about side effects has led to the development of various regimes to minimise these risks. Some are based on the premise that intermittent dosing allows the body to recover from the effects of steroids by allowing a period off the drug (alternate day regimes, regimes using 10 days on steroids and 10 or 20 days off, or vice versa, weekend only regimes, etc.) with or without a reduction in the overall dose given. Other regimes (daily low dosing) aim to reduce the cumulative steroid dose.....

 Conclusions and workshop outcomes

1. It was agreed that the evidence for the use of daily steroids in DMD is now established and that trials of other treatments should be against this ‘gold standard’.

2. Many measures can be put in place to monitor for, minimise or treat predictable side effects and these should be standardised as much as possible. Guidelines developed from this meeting will be available through the ENMC website and are summarised in Table 2.

3. Patient information material is crucial and should be distributed through the patient and parent organisations, and also through the ENMC website.

4. There are many alternative steroid regimes in use in DMD without systematic evidence as to their efficacy or side effect profile compared to daily steroids. Hence, there continues to be polarisation of practice, and it is very difficult for families to get clear advice about the relative benefits of the different regimes on offer. Agreement was therefore reached that plans for a trial of different steroid regimes, to be run on an international basis, and supported by universally applicable monitoring protocols will be further developed. It would not be appropriate, however, for treatment with steroids in children who could potentially benefit to be withheld in advance of such a trial.

5. Alongside the major hypothesis, trials of cardiac and bone protection will also be planned, as well as the issue of possible benefit in starting steroids in young people with DMD after the loss of ambulation.

6. There are areas where further attention needs to be paid to development of more specific outcome measures, especially in the area of quality of life.

I had posted some information about this meeting in 10/04/04.

16/07/04: (In Press: Molecular Genetics and Metabolism,2004) Expression of a NOS transgene in dystrophin-deficient muscle reduces muscle membrane damage without increasing the expression of membrane-associated cytoskeletal proteins 

James G. Tidball, and Michelle Wehling-Henricks - USA

Abstract

Muscular dystrophy that is caused by mutation of the membrane-associated, cytoskeletal protein called dystrophin, is accompanied by loss of a dystrophin-associated protein complex (DPC) that includes neuronal nitric oxide synthase (nNOS). Previous work showed that expression of a nNOS transgene in the dystrophin-deficient, mdx mouse greatly reduces muscle membrane damage. In this investigation, we test whether expression of a nNOS transgene in wild-type or mdx muscle increases expression of DPC proteins, or functionally related proteins in the integrin complex that are upregulated in dystrophin-deficiency, or affects expression of the dystrophin homolog, utrophin. Many members of the DPC are enriched in Western blots of cell membranes isolated from NOS transgenic muscle, compared to wild-type. Similarly, alfa7-integrin and the associated cytoskeletal proteins talin and vinculin are increased in NOS transgenic, non-dystrophic muscle. However, utrophin expression is unaffected by elevated NOS expression in healthy muscle. A similar trend in mRNA levels for these proteins was observed by expression profiling. Analysis of membrane preparations from mdx mice and NOS transgenic mdx mice shows that expression of the NOS transgene causes significant reductions in utrophin, talin, and vinculin. Expression profiling of mRNA from mdx and NOS transgenic mdx muscles also shows reduced expression of talin. Immunohistochemistry of mdx and NOS transgenic mdx muscle indicates that reduction in utrophin in NOS transgenic mdx muscle results from a decrease in regenerative fibers that express high levels of utrophin. Together, these findings indicate that the NOS transgene does not reduce dystrophinopathy by increasing the expression of compensatory, structural proteins.

16/07/04: (In Press: Molecular Therapy,2004) Therapeutic Antisense-Induced Exon Skipping for Duchenne Muscular Dystrophy

Annemieke Aartsma-Rus,Anneke A. M. Janson, Wendy E. Kaman, Mattie Bremmer-Bout, Christa L. de Winter, Habte F. Teshale, Gert-Jan B. van Ommen, Johan T. den Dunnen, Judith C. T. van Deutekom. - Netherlands

The severe Duchenne muscular dystrophy (DMD) is mostly caused by frame disrupting mutations in the dystrophin gene, which result in non-functional dystrophin proteins. Mutations that keep the reading frame intact give rise to internally deleted, semi-functional dystrophins and result in the milder Becker muscular dystrophy (BMD). Antisense oligonucleotides (AONs) have the potential to modulate the pre-mRNA splicing such that a specific exon is skipped. As a result, the reading frame can be restored, which allows the synthesis of a BMDlike dystrophin. To date, we have induced the skipping of 20 different DMD exons in human control myotubes and confirmed the therapeutic applicability of the strategy in myotube cultures from 10 different DMD patients. Following transfection of specific AONs dystrophin synthesis was restored in over 75% of treated myotubes. Furthermore, we recently demonstrated the feasibility of skipping two and even multiple consecutive exons, simultaneously. This double- and multi-exon skipping would not only further increase the therapeutic applicability to over 90% of patients, but also render this therapy significantly less mutation-specific....

16/07/04: Human circulating AC133(+) stem cells restore dystrophin expression and ameliorate function in dystrophic skeletal muscle

13/07/04: PTC Therapeutics Initiates Clinical Trials of PTC124 for Cystic Fibrosis and Duchenne Muscular Dystrophy

13/07/04: Tarantula Venom Peptide Shows Promise as a Drug

12/07/04:  (IN PRESS (Neuromuscular Disorders, 2004)) Therapeutic efforts in Duchenne muscular dystrophy; the need for a common language between basic scientists and clinicians

Victor Dubowitz, UK

Abstract

Major advances in molecular genetics of Duchenne dystrophy over the past decade have generated a flurry of attempts at potential cell and gene therapy, mainly in the dystrophin-deficient mdx mouse. This has been accompanied by a fanfare of publicity, in both scientific and lay press, producing waves of hope followed by troughs of disappointment and frustration in both patients and their families and in the scientific community. It has also spawned an additional problem in the use of inappropriate terminology to describe clinical or pathological changes in experimental animal studies, which have been equated with the human disease. It seemed timely to address and hopefully redress the problem, and suggest some solutions, aimed at finding a common language for basic and clinical scientists in their therapeutic efforts in relation to Duchenne dystrophy. Core problems include equating the mdx mouse, with its very mild clinical phenotype, and Duchenne dystrophy; use of inappropriate and often emotive terminology to describe pathological changes, such as ‘rescue’, ‘reversal’, ‘prevention’, ‘phenotype’, instead of clear descriptive language; and use of the term therapy in place of experiment in both laboratory and clinical experiments targeting single muscles. A major missing link in these multidisciplinary efforts is the absence of mouse doctors, who can define at a clinical level the motor, respiratory and cardiac deficits in the dystrophic animal, and bridge the huge gap between the mouse scientists doing experimental studies in the laboratory and the clinicians and veterinarians caring for humans and dogs with these disorders.

12/07/04: (Learning Disabilities Research & Practice. 19(3):146-154, 2004) Investigation of Poor Academic Achievement in Children with Duchenne Muscular Dystrophy

Hinton, V. J.; De Vivo, D. C.; Fee, R.; Goldstein, E.; Stern,Y. - USA

Abstract

Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disorder that presents with progressive muscular weakness. It is caused by a mutation in a gene that results in the absence of specific products that normally localize to muscle cells and the central nervous system (CNS). The majority of affected individuals have IQs within the normal range, generally with lower verbal than performance IQ scores. Prior work has demonstrated selective deficits on tests of verbal span and immediate memory. For the current study, 26 boys with DMD (and normal intellectual function) and their unaffected siblings were evaluated. Paired comparisons demonstrated that the children with DMD had significantly poorer academic achievement scores than their siblings, even though their vocabulary levels and home and educational environments were comparable. Children with DMD also had more behavioral concerns, physical disabilities, and poorer verbal memory spans. Linear regression indicated that behavioral concerns, executive function, and physical disability did not contribute substantially to academicperformance, whereas performance on verbal span did. DMD presents with a selective developmental aberration in verbal span that has wide-ranging consequences on learning skills.
  

11/07/04: (PEDIATRIC NEUROLOGY Vol. 31(1): 16-19, 2004) Depression in Parents of Children With Duchenne Muscular Dystrophy

Abi Daoud, MS; Dooley, JM; Gordon, KE - Canada

This study examined depression, self-esteem, and mastery in the family caretakers of a group of males with Duchenne muscular dystrophy in comparison to a control group. A questionnaire based on the National Population Health Survey from Statistics Canada, a survey to collect information on the health of the Canadian population and related sociodemographic information, was conducted by telephone with 42 parents. The results were compared with the national data from the National Population Health Survey (1994 and 1999), matched for province of residence, number of children in the household, age, and marital status of the respondents. Parents of children with Duchenne muscular dystrophy had a higher probability of going through a major depressive episode and had significantly lower self-esteem and mastery scores than the national control group. None of the variables investigated (age, intelligence quotient, and ambulatory status of child or sex, age, and marital status of parent) could predict the depressive episode, with two exceptions. Parents without a partner had lower scores on the mastery scale, and parents of males older than 13 years of age were more likely to experience distress that interfered with life. It is incumbent on those caring for patients with Duchenne muscular dystrophy to counsel families regarding their potential to suffer a major depressive episode and to advise on appropriate therapy.

06/07/04: The relationship between clinical stage, prognosis and myocardial damage in patients with Duchenne-type muscular dystrophy: five-year follow-up study

02/07/04: Muscle in Wyeth's Pipeline

JUNE/2004

23/06/04: Myostatin Mutation Associated with Gross Muscle Hypertrophy in a Child

Gene Mutation Found in Muscle Man Toddler

Super-Strong Toddler Studied For Muscle-Wasting Cure

Scientists Study 'Baby Superman'

12/06/04: Regenerative capacity of the dystrophic (mdx) diaphragm after induced injury

11/06/04: Full-length dystrophin expression in half of the heart cells ameliorates beta-isoproterenol-induced cardiomyopathy in mdx mice

09/06/04: MDA TO PLAN NORTH AMERICAN CLINICAL TRIALS NETWORK FOR MUSCULAR DYSTROPHY

08/06/04:THE STATE OF THE ART IN THE MANAGEMENT OF OSTEOPOROSIS  

Glucocorticoid-Induced Osteoporosis

Prolonged exposure to glucocorticoids has long been associated with osteoporosis and increased fracture risk. Several recent clinical studies have defined the scope of this problem, confirming that prolonged glucocorticoid use is an independent risk factor for fracture. In a study of 191 general-practice patients in Iceland who were taking glucocorticoids for 3 months or longer (mean dosage, 6 mg/day), 26% of patients were diagnosed with osteoporosis and 20% experienced fractures. Among patients with rheumatoid arthritis, a disease that has been directly associated with bone loss, glucocorticoid use has been demonstrated to be an independent risk factor for fracture. After adjustment for other variables (ie, body mass index, smoking, alcohol use, and functional impairment), the odds ratio for hip fracture associated with rheumatoid arthritis was 1.3. The odds ratio for hip fracture associated with use of corticosteroids, adjusted for the same confounding variables, was substantially higher, 2.1. Fracture risk among users of glucocorticoids appears to be dose related, starting at relatively low doses (relative risk [RR] of hip fracture, 0.99, 1.77, and 2.27 at dosages of  <2.5 mg/day, 2.5 to 7.5 mg/day, and >7.5 mg/day [prednisone or its equivalent], respectively, and RR of vertebral fracture, 1.55, 2.59, and 5.18, respectively). Therefore, even patients taking prolonged courses of relatively low doses of glucocorticoids should be considered at risk for osteoporosis and fractures. Baseline bone status may also help predict fractures. In a recent study, lower baseline lumbar spine BMD was associated with increased fracture risk. Current guidelines set forth by the American College of Rheumatology recommend obtaining a baseline measurement of BMD for all patients initiating long-term (>6 months) glucocorticoid therapy. Calcium and vitamin D are recommended for all patients receiving glucocorticoids, and bisphosphonates are approved for both prevention (risedronate) and treatment (alendronate and risedronate) of glucocorticoid-induced bone loss in patients at high risk for fractures.

 

06/06/04: (Current Paediatrics (2004) 14, 214–222) - Recent advances in paediatric muscular dystrophies

Kate Bushby - UK

Summary: The inherited muscle diseases of childhood remain a significant cause of disability. Enormous progress in determining the underlying genetic causes of these disorders has led to much greater precision in diagnosis and better guidance about prognosis for individual conditions. This has been particularly striking in recent years in the elucidation of the genetic basis for muscular dystrophies presenting in the first year of life (the congenital muscular dystrophies) or later in childhood (Duchenne and Becker muscular dystrophies, Emery–Dreifuss muscular dystrophy and the limbgirdle muscular dystrophies). Improved understanding of pathogenesis and disease progression means that management interventions can be more logically planned, allowing a considerable impact on well-being and longevity. Support for respiratory impairment and cardiac and nutritional problems can be logically planned and applied in a disease-specific manner. The potential of gene-based therapies for these conditions, or specific pharmacological modification of the phenotype, remains a major goal of basic research.

About Duchenne Muscular Dystrophy:

Duchenne and Becker muscular dystrophy The discovery in 1987 of the dystrophin gene as the cause of Duchenne and Becker muscular dystrophies (DMD and BMD) was a major milestone in the characterisation of all other inherited muscle diseases. Molecular diagnosis via DNA analysis in DMD and BMD is now standard practice, at least for the deletion and duplication mutations that account for the disease in approximately 60–70% of cases. It remains disheartening that, while diagnosis of DMD is now routine at the molecular level, the age at diagnosis remains over 4.5 years.14 Early diagnosis is important to allow family counselling and begin appropriate management. Continuing education of primary care and community staff coming into contact with preschool children is needed to promote the early diagnosis of this condition: for example, by having a low threshold for testing serum CK levels in young boys who are not walking by the age of 18 months, or who fail to learn to run or jump normally. After years of uncertainty and debate about the medical treatment of DMD, a consensus is beginning to emerge that several key points of management are likely to improve prognosis in this condition. Two large-scale systematic reviews of the use of corticosteroids to improve muscle strength in DMD conclude that daily corticosteroid treatment does improve muscle strength, and is likely to (1) prolong ambulation, (2) delay or reduce the need for spinal surgery, (3) promote the maintenance of respiratory function, and (4) have (possibly) a cardioprotective effect.15,16 These effects seem to be the same with the use of either prednisolone or deflazacort. However, it is also clear that longterm use of steroids is associated with a risk of clinically significant side-effects. Prednisolone appears to have a higher association with weight gain than deflazacort, which has a higher incidence of (usually asymptomatic) cataracts. Both treatments may be associated with an increase in osteoporosis that may result in vertebral fractures. So while steroid treatment is probably effective in increasing muscle strength in most boys with DMD, the treatment needs to be carefully monitored and the dose titrated if necessary. Further studies are required to explore the use of alternative steroid regimes. A greater understanding of the underlying disease course in DMD and the availability of treatments to modify the complications of cardiomyopathy and progressive respiratory failure have also altered the natural history of this condition. Surveillance for cardiac impairment and treatment of progressive abnormalities with ACE inhibition and b blockade, even in the absence of symptoms, has now been recommended. Cardiomyopathy in DMD occurs in almost all patients, but is usually asymptomatic because of the low levels of activity. For patients with the milder allelic condition BMD, and for a small proportion of carriers of DMD and BMD, cardiac complications are also important and may be out of proportion to the skeletal muscle disease. Cardiac surveillance is crucial to allow intervention before an untreatable cardiomyopathy supervenes. Finally, proper respiratory care (including monitoring for the inexorable decline in respiratory function seen in DMD, and intervention with nocturnal ventilation where indicated) has dramatically altered lifespan in DMD, which should no longer be regarded necessarily as a disorder which is uniformly lethal in childhood. This change in life expectancy has important social implications for the affected young person and his family.

Practice points for management of DMD:

06/06/04: Progression of scoliosis after spinal fusion in Duchenne's muscular dystrophy NEW

06/06/04: Sacral Nerve Stimulation for Treatment of Fecal Incontinence in a Patient With Muscular Dystrophy: Report of a Case NEW

02/06/04: IN PRESS (Neuroscience Letters, 2004): Cardiomyopathy in Muscular Dystrophy Workshop 28–30 September 2003, Tucson, Arizona NEW

Clinical Recomendations:

The European Neuromuscular Centre convened a meeting in 2002 on Cardiomyopathy and Muscular Dystrophy. Kate Bushby presented the findings and recommendations from that gathering. At the 2002 meeting and the present meeting, it was agreed that clinical studies were not available to provide specific recommendations regarding the management of cardiomyopathy in muscular dystrophy. The rare nature of these disorders leads to difficulty in assembling sufficient numbers of subjects for controlled clinical trials. As such, multicenter-based trials are needed, and multicenter trials are just beginning. The complexity in conducting these trials also includes the determination of adequate endpoints and uniformity in performance and interpretation of noninvasive studies. Carolyn Spencer reviewed the use of echocardiography as a tool to predict outcome in subjects with cardiomyopathy. In some studies, left ventricular function has been used as an endpoint for studies of heart failure, and it may be useful for studies of the heart failure that accompanies muscle disease. Paula Clemons is working with Cooperative International Neuromuscular Research Group (CINRG) to begin a study of the efficacy of Co enzyme Q10 and prednisone in children with DMD. An arm of this study will evaluate the effect of these medications on cardiac function including wall stress, shortening fraction, and tissue Doppler imaging. Valerie Cwik discussed the ongoing MD STARNet study sponsored by the Centers for Disease Control. Its goals are to determine whether there has been a change in the prevalence of DMD and to determine what treatment is being offered to children with DMD. Until controlled clinical trials are available for cardiomyopathy with muscular dystrophy, recommendations for clinical care should rely on controlled clinical trials of heart failure and cardiomyopathy. The mainstay of pharmacologic treatment for left ventricular dysfunction for adults with cardiomyopathy and CHF relies on (1) afterload reduction with ACE inhibitors as a first line option and angiotensin receptor blockade if ACE inhibitors cannot be used, (2) beta adrenergic receptor blockade, (3) spironolactone, (4) diuretics as needed to manage fluid overload, and (5) aggressive surveillance for cardiac arrhythmias. The role of additional pharmacologic agents such as digoxin is not clear. Arrhythmias, if detected or suspected, can be treated by device implantation and/or pharmacologic therapy with antiarrhythmic agents. Surveillance should include regular EKGs, Holter monitoring and/or event monitoring. Syncope, if noted, may warrant treatment for presumed arrhythmias. Similar therapies in children, with the use of ACE inhibitors and b-blockers with or without diuretics and digoxin, are first line approaches. The specific recommendations may be modified with regard to the precise gene defect. In DMD, heart involvement generally occurs later than skeletal muscle involvement and may not be present until the late second decade. It is not known at this time whether early treatment, before the visible onset of left ventricular dysfunction may slow the course of cardiomyopathy. Future clinical trials should be designed to determine at what age and at what stage therapy to prevent cardiomyopathy should be initiated. As these problems can become evident in the early second decade, monitoring should begin at that time. Cardiologists, whether specialized in the care of adult or pediatric patients, should be experienced in caring for subjects with muscular dystrophy. The Muscular Dystrophy Association may wish to identify a referral base of cardiologists who work with the MDA clinics throughout the country. In BMD, cardiac involvement may occur later but may eventually become a prominent feature. Cardiac transplantation can be offered if pharmacologic therapy fails. Monitoring should begin in the late second decade for BMD. Finally, female carriers of dystrophin mutations should be evaluated beginning in their late 3rd to 4th decade since cardiomyopathy may develop in these subjects.

MAY/2004

24/05/04: Therapeutic gene transfer to dystrophic diaphragm by an adenoviral vector deleted of all viral genes  

24/05/04: Cardiopulmonary failure in Duchenne muscular dystrophy--pathophysiology and management

24/05/04: Decreased total nitric oxide production in patients with duchenne muscular dystrophy

21/05/04: Ultrastructural changes in muscular tissues of dystrophin/utrophin double-knockout mice after bone marrow-derived mesenchymal stem cell transplantation

18/05/04: Creatine monohydrate enhances strength and body composition in Duchenne muscular dystrophy

Tarnopolsky, M.A. MD, PhD; Mahoney, D.J. BSc; Vajsar, J. MD; Rodriguez, C. BSc; Doherty, T.J. MD, PhD; Roy, B.D. PhD; Biggar, D. MD

Neurology,62(10):1771-7, may 2004

Abstract

Objective: To determine whether creatine monohydrate (CrM) supplementation increases strength and fat-free mass (FFM) in boys with Duchenne muscular dystrophy (DD).

Methods: Thirty boys with DD (50% were taking corticosteroids) completed a double-blind, randomized, cross-over trial with 4 months of CrM (about 0.10 g/kg/day), 6-week wash-out, and 4 months of placebo. Measurements were completed of pulmonary function, compound manual muscle and handgrip strength, functional tasks, activity of daily living, body composition, serum creatine kinase and [gamma]-glutamyl transferase activity and creatinine, urinary markers of myofibrillar protein breakdown (3-methylhistidine), DNA oxidative stress (8-hydroxy-2-deoxyguanosine [8-OH-2-dG]), and bone degradation (N-telopeptides).

Results: During the CrM treatment phase, there was an increase in handgrip strength in the dominant hand and FFM (p < 0.05), with a trend toward a loss of global muscle strength (p = 0.056) only for the placebo phase, with no improvements in functional tasks or activities of daily living. Corticosteroid use, but not CrM treatment, was associated with a lower 8-OH-2-dG/creatinine (p < 0.05), and CrM treatment was associated with a reduction in N-telopeptides (p < 0.05).

Conclusions: Four months of CrM supplementation led to increases in FFM and handgrip strength in the dominant hand and a reduction in a marker of bone breakdown and was well tolerated in children with DD.

18/05/04: Myoblast survival enhancement and transplantation success improvement by Heat-Shock treatment in mdx mice  

Bouchentouf, Manaf; Benabdallah, Basma F.; Tremblay, Jacques P.

Transplantation. 77(9):1349-1356, May 15, 2004

Abstract

Background. Duchenne muscular dystrophy is a disease caused by the incapacity to synthesize dystrophin, which is implicated in the maintenance of the sarcolemma integrity. Myoblast transplantation is a potential treatment of this disease. However, most of the transplanted cells die very rapidly after their injection. Heat-shock proteins (HSPs) are over-expressed when cells undergo various types of stresses. Our goal was thus to investigate whether the expression of HSPs (HSP70 in particular) could protect myoblasts from death after intramuscular injection.
Methods. HSP70 expression was induced by warming the cells at 42[degrees]C for 60 minutes. HSP70 over-expression was quantified by Western blot analysis. The in vitro effect of HSPs on cell survival was evaluated by fluorescence-activated cell sorter analysis using the Hoescht/propidium iodide-labeling technique, and their in vivo effects were investigated by transplanting TnI-LacZ myoblasts labeled with [methyl-14C] thymidine.
Results. Western blots indicated a sevenfold over-expression of the HSP70 after the heat-shock treatment. In vitro, the heat-shock treatment protected 18% of the cells from staurosporine- (1 [mu]M) induced apoptosis. HSPs also protected 10% of the cells from death induced by either tumor necrosis factor-[alpha] (30 ng/mL) or glucose oxydase (0.1 U/mL). In vivo, the treatment improved the cell survival by twofold 5 days after the graft and increased by fourfold the long-term graft success.
Conclusions. The heat-shock treatment is a practical approach for improving the success of myoblast transplantation; in fact, using this kind of treatment, there is no need to genetically modify the cells before their transplantation.


17/05/04: Effect of creatine supplementation on skeletal muscle of mdx mice

17/05/04: Informations about the clinical trial "Prednisone and Cyclosporin A in DMD" from Prof.Dr. Rudolf Korinthenberg:

Thank you for your interest. Our study is a randomized placebo controlled trial that started in January 2004. There are 10 study centers in Germany, Swizzerland and probably Austria who will have ti recruit 150 Boys over 5 years. During the first 3 months of treatment we compare Cyclosporin monotherapy to placebo. We want to see whether strength increases as awas suggested by 2 open studies. During the following 12 months both groups (CsA and Placebo) will in addition be treated with prednisone in an intermittent scheme. Here we want to find out whwther the effect of prednisone can be improved by CsA. Additionally, of course, we monitor side effects. Thanks for your interest, sincerely, Rudolf Korinthenberg

Previous studies with cyclosporin:

1993 - Neurology, Vol 43, Issue 3 527-532: Cyclosporine increases muscular force generation in Duchenne muscular dystrophy KR Sharma, MA Mynhier and RG Miller
We investigated the effect of cyclosporine (CsA) on force generation in 15 boys with Duchenne muscular dystrophy (DMD) by obtaining monthly measures of tetanic force and maximum voluntary contraction (MVC) of both anterior tibial muscles. During 4 months of a natural history phase, both tetanic force and MVC declined significantly. During 8 weeks of CsA treatment (5 mg/kg/day), significantly increased tetanic force (25.8 +/- 6.6%) and MVC (13.6 +/- 4.0%) occurred within 2 weeks. The maximum mean increase during treatment was 35.2 +/- 5.9% (tetanic force) and 19.0 +/- 4.6% (MVC). Side effects from CsA, gastrointestinal and flu-like symptoms, were transient and self-limiting. Thus, as previously reported with prednisone, CsA increases muscular force generation in the anterior tibial muscles of DMD patients. 

1997 - Muscle Nerve, 20, 469–478. Myoblast implantation in Duchenne Muscular Dystrophy: The San Francisco Study

ABSTRACT: We evaluated myoblast implantation in 10 boys with Duchenne muscular dystrophy (DMD) and absent dystrophin (age 5–10 years) who were implanted with 100 million myoblasts in the anterior tibial muscle of one leg and placebo in the other. Cyclosporine (5 mg/kg/day) was administered for 7 months. Pre- and postimplantation (after 1 and 6 months) muscle biopsies were analyzed. Force generation (tetanic tension and maximum voluntary contraction) was measured monthly in a double-blind design. There was increased force generation in both legs of all boys, probably due to cyclosporine. Using the polymerase chain reaction, evidence of myoblast survival and dystrophin mRNA expression was obtained in 3 patients after 1 month and in 1 patient after 6 months. These studies suggest a salutary effect of cyclosporine upon muscular force generation in Duchenne muscular dystrophy; however, myoblast implantation was not effective in replacing clinically significant amounts of dystrophin inDMD muscle. 

 

15/05/04: MD Net therapy study R19 "Prednisone and Cyclosporin A" started  

The partial therapy study R19 "Immunsuppressive therapy of the DMD  with low dosis Prednisone and Cyclosporin A", financed by action benni & CO e.V., is now started. The first patients are already taken up to the study. In Germany the therapy study is accomplished at the following nine muscle centers : Berlin University, Dr. A. von Moers; Dresden University, PD. Dr. A. Huebner, Dr. A. Kaindl; Essen University, Professor Dr. Th. Voit; Freiburg University, Dr. J. Schessl, Professor Dr. R. Korinthenberg; Goettingen University, Professor Dr. E. Wilichowski; Kiel University, Professor Dr. And Stephani; Mainz University, Professor Dr. B. Reitter; Munich University, Professor Mueller Mueller-Felber; Urban hospitals Neuss, Dr. And Schara. In order to participate in the study you should turn to the specified muscle centers. Coordenation of this study: Dr. Rudolf Korinthenberg and Dr. Joachim Schessl (Freiburg University). More information in this website: http://www.abc-online.org/ (in germany).

15/05/04: Highly efficient EIAV-mediated in utero gene transfer and expression in the major muscle groups affected by Duchenne muscular dystrophy

11/05/04: Small-molecule gene therapy nearing trials  

11/05/04: Regeneration of injured muscle from adult stem cells

09/05/04: IN PRESS (Neuroscience Letters, 2004) Okadaic acid augments utrophin in myogenic cells 

Marianna Rodova, Kyle Brownback, Michael J. Werle - USA

Abstract

Duchenne muscular dystrophy is a fatal childhood disease caused by mutations that abolish the expression of dystrophin in muscle. Utrophin is a paralogue of dystrophin and can functionally replace it in skeletal muscle. A potential therapeutic approach is to increase utrophin levels in muscle. One way to achieve this aim is to increase the expression of the utrophin gene at a transcriptional level via promoter activation. In this study, we have shown that utrophin A mRNA levels can be induced by okadaic acid in murine myogenic C2C12 cells. We have found that a utrophin A promoter reporter can be induced by Sp1 in C2C12 myoblasts, but not in myotubes. This activation can be enhanced by okadaic acid treatment. Our data suggest that this induction is due to Sp1 phosphorylation during myogenesis and thus, utrophin expression in muscle could be regulated by treatment with phosphatase inhibitors. Control of utrophin promoter activation could then be used to increase the expression of utrophin, and thus ameliorate the symptoms of Duchenne muscular dystrophy.

03/05/04: ABSTRACTS THAT WILL BE PRESENTED IN THE 7TH ANNUAL MEETING OF THE AMERICAN SOCIETY OG GENE THERAPY, JUNE 2-6, MINNEAPOLIS, MINNESOTA : are there a real advance?

1) Micro-Utrophin as a Therapeutic Protein in rAAV Mediated Gene Therapy for Duchenne Muscular Dystrophy

2)Gender Differences in Transplantation Efficiency Using Muscle-Derived Stem Cells for Muscular Dystrophy

3) Therapeutic Antisense-Induced Exon Skipping for Duchenne Muscular Dystrophy

4) New Canine Models of Duchenne Muscular Dystrophy: Identification and Molecular Characterization

5) A Novel MiniDys-eGFP Fusion Gene for Developing Cell-Based Therapies of Duchenne Muscular Dystrophy

6) Expressing Full-Length Dystrophin in 50% Cardiomyocytes Corrects Cardiomyopathy in the Mdx Mouse Model for Duchenne Muscular Dystrophy

7) Expression of Normal Dystrophin Following Myoblast Transplantation to Duchenne Muscular Dystrophy Patients

8) rAAV-Mediated Gene Therapy To Treat Limb Girdle Muscular Dystrophy Type 2D (LGMD-2D)

9) Transgenic Expression of Dp116 in Muscle Does Not Ameliorate Dystrophy in mdx4cv Mice

10) Systemic Gene Transfer to Striated Muscles Using rAAV6 Vectors

11) Lentivirus Mediated Dystrophin Expression in mdx Muscles

12) Nucleofection and Phage phiC31 Integrase Mediate Stable Introduction of a Dystrophin Fusion Gene into Muscle Derived Stem Cell and Human Myoblasts

13) Successful AAV Vector-Mediated Gene Transfer into Canine Skeletal Muscle Required Suppression of Excess Immune Responses

14) An AAV Vector-Mediated Micro-Dystrophin Expression in Relatively Small Percentage of Dystrophin-Deficient mdx Myofibers Still Improved the mdx Phenotype through Compensatory Hypertrophy

15) Muscle-Derived Stem Cells Display an Extended, but Not Unlimited, Expansion Capability: Implication for Muscle Regeneration

16) Delivery of Igf-I and Dystrophin to Dystrophic mdx Muscle

17) Immunogenicity of Dystrophins Delivered to Mice by Gutted Adenoviral Vectors

18) Human Myoblast Deimmortalization Using Tat-Mediated Cre Recombinase Delivery

19) The Fetal Approach: A Novel Therapy for the Treatment of Musculo-Skeletal Disease

20) In Utero Intramuscular Delivery of a High-Capacity Adenoviral Vector Carrying a Full-Length Murine Dystrophin cDNA Provides Functional Benefit and Reassembly of the Dystrophin-Glycoprotein Complex in Hind Limb Muscles of mdx Mice


1/05/04: Pneumothorax associated with long-term non-invasive positive pressure ventilation in Duchenne muscular dystrophy

APRIL/2004

27/04/04: Surgical treatment of spinal deformities in Duchenne muscular dystrophy: a long term follow-up study

27/04/04: IN PRESS (Experimental Cell Research, 2004) Improvement of calcium handling and changes in calcium-release properties after mini- or full-length dystrophin forced expression in cultured skeletal myotubes

Eric Marchand, Bruno Constantin, Haouaria Balghi, Marie-Christine Claudepierre, Anne Cantereau, Christophe Magaud, Aklesso Mouzou, Guy Raymond, Serge Braun, and Christian Cognard - FRANCE

Abstract

Dystrophin is a cytoskeletal protein normally expressed underneath the sarcolemma of muscle fibers. The lack of dystrophin in Duchenne muscular Dystrophy (DMD) muscles results in fiber necrosis, which was proposed to be mediated by chronic calcium mishandling. The extensive comparison of dystrophic cells from human or mdx mice with normal muscles have suggested that the lack of dystrophin may alter the resting calcium permeability and steady-state levels of calcium, but this latter observation remains controversial. It is also not clear, whether calcium mishandling is resulting from the dystrophic process or if dystrophin can directly regulate calcium handling in muscle cells.This prompted us to determine if transfection of full-length dystrophin or Becker Muscular Dystrophy (BMD) minidystrophin, a candidate for viral-mediated gene therapy, could change calcium handling properties. We took advantage of specific properties of Sol8 cell line showing the absence of dystrophin expression together with a drastic calcium mishandling. Here, we show that full-length dystrophin allowed the recovery of a low resting intracellular-free calcium concentration together with lower calcium transients. We also show for the first time that stable expression of minidystrophin was able to restore normal calcium handling in Sol8 myotubes through a better control of steady-state levels, calcium transients, and subcellular calcium events. It suggests that dystrophin could play a regulatory role on calcium homeostasis apparatus and that functional links exist between calcium signaling and cytoskeleton.

27/04/04: Chimeric RNA and 2'-O, 4'-C-ethylene-bridged nucleic acids have stronger activity than phosphorothioate oligodeoxynucleotides in induction of exon 19 skipping in dystrophin mRNA.  

24/04/04: Glucocorticoid corticosteroids for Duchenne muscular dystrophy

24/04/04: Cloning of cDNA Encoding a Regeneration-Associated Muscle Protease Whose Expression Is Attenuated in Cell Lines Derived from Duchenne Muscular Dystrophy Patients  

23/04/04: Selected articles (8)from ATS - 2004 (American Thoracic Society International Meeting) - May 21-26, 2004  

Selected articles (22) from ATS - 2003,2002,2001 (American Thoracic Society International Meeting)  

21/04/04: IN PRESS (Neuromuscular Disorders, 2004) Prednisone reduces muscle degeneration in  dystrophin-deficient Caenorhabditis elegans

Aurélie Gaud, Jean-Marc Simon, Thomas Witzel, Maité Carre-Pierrat, Camille G. Wermuth, Laurent Ségalat - France

Abstract

Duchenne muscular dystrophy is a degenerative muscular disease caused by mutations in the dystrophin gene. There is no curative treatment against Duchenne muscular dystrophy. In several countries, the steroid prednisone (or analogs) is prescribed as a palliative treatment. In the model animal Caenorhabditis elegans, mutations of the dys-1 dystrophin-like gene lead to a muscular degenerative phenotype when they are associated with a mild MyoD mutation. This cheap and fast-growing model of dystrophinopathy may be used to screen for molecules able to slow muscle degeneration. In a blind screen of approximately 100 compounds covering a wide spectrum of targets, we found that prednisone is beneficial to the C. elegans dystrophin-deficient muscles. Prednisone reduces by 40% the number of degenerating cells in this animal. This result is a proof-of-principle for the use of C. elegans as a tool in the search for molecules active against the effects of dystrophin-deficiency. Moreover, since C. elegans is not susceptible to inflammation, this suggests that prednisone exerts a direct effect on muscle survival.

 

17/04/04: IN PRESS (Neuromuscular Disorders, 2004) Inducing muscle hypertrophy as a therapeutic strategy for muscular dystrophies. 122nd ENMC International Workshop, Naarden, The Netherlands, 28–30 November 2003 

Ketan Patel, Francesco Muntoni - London

Patients with a variety of neuromuscular disorders and most noticeably with muscular dystrophies experience profound muscle wasting. In muscular dystrophies this is believed to be the result of increased muscle damage and progressive loss of regeneration capacity by the satellite cells. Muscle wasting is also a process that occurs during ageing. Recent studies suggest that the muscle atrophy observed both in aged and dystrophic muscle can be effectively counteracted by strategies aimed at inducing an increase in muscle mass. To this end animal models have been developed such as those conditionally over expressing insulin-like growth factor 1 (IGF-1) in skeletal muscle, which resulted in sustained hypertrophy. This not only preserved the muscle mass in ageing skeletal muscle, but also improved the function of dystrophic muscle in the mdx mouse, the animal model for Duchenne muscular dystrophy. Interference with myostatin function by transgenic approach or using blocking antibodies, has resulted in functional improvement of the dystrophic histological and clinical phenotype in mdx mice. These approaches suggest that interfering with the programme of skeletal muscle regeneration and growth can lead to potential benefit in patients with muscular dystrophies and, potentially, other neuromuscular disorders and possibly the entire ageing population. We recently convened a European Neuromuscular Centre Workshop in which 18 participants from five countries (France, Germany, Italy, UK and USA) working on cellular and molecular aspects discussed the topic of ‘inducing muscle hypertrophy as a therapeutic strategy for muscular dystrophies’.

17/04/04: Use of the Mechanical In-Exsufflator in Pediatric Patients With Neuromuscular Disease and Impaired Cough

10/04/04: Treatment of Duchenne muscular dystrophy - defining the gold standards of management - 124th ENMC International Workshop

10/04/04:  IN PRESS (Neuromuscular Disorders, 2004) - Optimization of power wheelchair control for patients with severe Duchenne muscular dystrophy

Nadine Pellegrini, Bruno Guillon, Helene Prigent, Michel Pellegrini, David Orlikovskia, Jean-Claude Raphael, Frederic Lofaso, - France

Abstract

The extended survival of patients with Duchenne muscular dystrophy (DMD) achieved by the introduction of mechanical ventilation is raising new quality-of-life issues. We evaluated passive range of wrist extension, key pinch strength, and power wheelchair driving in 84 patients. The 47 drivers with restricted driving abilities were older than the 37 unrestricted drivers (27.2 + 5.0 y vs. 22.8 + 3.8 y) and had worse upper limb performance. By multiple logistic regression, only key pinch was significant (R2 = 0,224; P = 0:02). Eighteen restricted drivers were reassessed after having swapped a conventional joystick for another control system (mini-joystick, isometric mini-joystick, finger joystick, or pad) and having moved the position of the tested control system so that the patient could use it with different fingers, his chin or his mouth. All of them regained the ability to drive unrestricted. Adults with DMD gradually lose their ability to drive with a conventional joystick but can regain unrestricted driving with alternative control systems.

07/04/04: Gene therapy restores mouse lung function

02/04/04:Anti-TNFalpha (Remicade) therapy protects dystrophic skeletal muscle from necrosis

02/04/04: New funding for Duchenne muscular dystrophy research in UK

MARCH/2004

20/03/04: The anabolic androgenic steroid oxandrolone in the treatment of wasting and catabolic disorders : review of efficacy and safety

18/03/04: Evidence of early impairments in both right and left ventricular inotropic reserves in children with Duchenne's muscular dystrophy

17/03/04 IN PRESS (Medical Hypotheses, 2004): Erythropoietin: a new tool for muscle disorders?

C. Scoppetta, F. Grassi (E-mail address: ciriaco.scoppetta@uniroma1.it (C. Scoppetta).) 

Summary The main action of erythropoietin (EPO) is to regulate the production of red cells. However both experimental evidence and clinical experience suggest that erythropoietin has a positive effect on skeletal and cardiac muscle. Mice lacking EPO or its receptors suffer from hearth hypoplasia and have a reduced number of proliferating cardiac myocytes. EPO receptors are expressed on mouse primary satellite cells and in cultured myoblasts, and their stimulation appears to enhance proliferation and reduce the differentiation of both cell types. Moreover EPO is capable of promoting angiogenesis in muscle cells, which provides an additional route to increase oxygen supply to active muscles. In men, the effects of EPO on muscle cells are suggested by the illegal use of EPO by agonistic and amateur athletes to enhance their performances. In some athletes EPO improved their long-duration muscular performances much more than expected on the basis of the increment of the blood hemoglobin alone. Our proposal is to investigate the effect of EPO treatment in various animal models of muscular dystrophies (MD), which are common hereditary primary muscle disorders characterized by muscle damage and wasting, to date without any effective treatment. The ability of EPO to induce the proliferation of satellite cells in the presence of differentiating conditions, typical of the damaged muscle, may represent a tool to expand the cellular population competent for muscle repair. This would lengthen the period when muscles can be efficiently repaired. In the presence of positive results, the possibility could be considered of selecting some of the human forms of MD and treating the patients with EPO.

16/03/04: What muscular dystrophy patients and their parents should know about steroid therapy

13/03/04: Abstracts from the 56th Annual Meeting - American Academy of Neurology (april 2004 in San Francisco) - probably this is the most important meeting from neurologists in the world. I found only 8 abstracts about DMD that will be presented in this meeting, and few in point of therapy (there are 157 abstracts about Parkinson, 257 about multiple sclerosis). There are few studies about therapy in the world, in special to stop or delay the evolution of the disease. I post the abstracts here

13/03/04: Urinary incontinence in a patient with Duchenne muscular dystrophy and cord in the normal position with fatty filum terminale

10/03/04: IN PRESS (Neurology, 2004,62) - Pilot trial of albuterol in Duchenne and Becker muscular dystrophy  

E.G. Fowler; M.C. Graves; G.T. Wetzel  and M.J. Spencer, 

Abstract—The authors conducted a randomized, crossover, double-blind, placebo-controlled pilot study of albuterol in nine boys with dystrophinopathies. Primary outcomes were 1) isometric knee extensor and flexor strength; and 2) manual muscle testing (MMT). Isometric knee extensor strength and MMT scores were significantly higher in patients taking albuterol vs placebo. Therefore, 12-week treatment with extended-release albuterol may increase strength in patients with dystrophinopathies. A larger, double-blind, randomized study is necessary to confirm these results. 

06/03/04: Specific cognitive deficits are common in children with Duchenne muscular dystrophy

03/03/04: Readthrough of dystrophin stop codon mutations induced by aminoglycosides  

03/03/04: Steroid Treatment and the Development of Scoliosis in Males with Duchenne Muscular Dystrophy

02/03/04: Systemic delivery of human microdystrophin to regenerating mouse dystrophic muscle by muscle progenitor cells

02/03/04: ß2-Agonist administration reverses muscle wasting and improves muscle function in aged rats

FEBRUARY/2004

28/02/04: Long-term expression of full-length human dystrophin in transgenic mdx mice expressing internally deleted human dystrophins

28/02/04: Restoration of dystrophin expression in mdx mice by intravascular injection of naked DNA containing full-length dystrophin cDNA

28/02/04: Mini-dystrophin restores L-type calcium currents in skeletal muscle of transgenic mdx mice

28/02/04: Transforming Growth Factor-ß1 Induces the Differentiation of Myogenic Cells into Fibrotic Cells in Injured Skeletal Muscle

25/02/04: Dystrophin deletions and cognitive impairment in Duchenne/Becker muscular dystrophy

21/02/04: Sustained Improvement of Muscle Function One Year After Full-Length Dystrophin Gene Transfer into mdx Mice by a Gutted Helper-Dependent Adenoviral Vector

21/02/04: Premature stop codons involved in muscular dystrophies show a broad spectrum of readthrough efficiencies in response to gentamicin treatment  

21/02/04: Loss of a single amino acid from dystrophin resulting in Duchenne muscular dystrophy with retention of dystrophin protein

07/02/04: Making new muscle: Researchers in Rome produce a mouse that can regenerate its tissues

Stem cell-mediated muscle regeneration is enhanced by local isoform of insulin-like growth factor 1

07/02/04: Viral expression of insulin-like growth factor-I enhances muscle hypertrophy in resistance-trained rats

07/02/04:Extracellular HMGB1, a signal of tissue damage, induces mesoangioblast migration and proliferation

07/02/04: Parent Project Muscular Dystrophy signs historic agreement with biotech to identify new Duchenne muscular dystrophy drug treatments

3/02/04: Xechem Files for FDA Orphan Drug Status for the Treatment of Muscular Dystrophy with MYODUR; MYODUR Recently Acquired Through Ceptor Merger

JANUARY/2004

31/01/04: Absence of Dystrophin in Mice Reduces NO-Dependent Vascular Function and Vascular Density: Total Recovery After a Treatment with the Aminoglycoside Gentamicin

25/01/04: Outcome of non-invasive positive pressure ventilation in paediatric neuromuscular disease

17/01/04: The calcineurin signal transduction pathway is essential for successful muscle regeneration in mdx dystrophic mice

17/01/04: Workshop: Management of adults and children with feeding difficulties secondary to chronic muscle disease, 22nd March 2002, Sheffield, UK

14/01/04: IN PRESS (Molecular Therapy, 2004): Dystrophin Expression in Myofibers of Duchenne Muscular Dystrophy Patients Following Intramuscular Injections of Normal Myogenic Cells   

Daniel Skuk, Brigitte Roy, Marlyne Goulet, Pierre Chapdelaine, Jean-Pierre Bouchard, Raynald Roy, Francine J. Dugre, Jean-Guy Lachance, Louise Deschenes, Helene Senay, Michel Sylvain, and Jacques P. Tremblay1,

E-mail: Jacques-P.Tremblay@crchul.ulaval.ca.

Three Duchenne muscular dystrophy (DMD) patients received injections of myogenic cells obtained from skeletal muscle biopsies of normal donors. The cells (30  106) were injected in 1cm3 of the tibialis anterior by 25 parallel injections. We performed similar patterns of saline injections in the contralateral muscles as controls. The patients received tacrolimus for immunosuppression. Muscle biopsies were performed at the injected sites 4 weeks later. We observed dystrophin-positive myofibers in the cell-grafted sites amounting to 9 (patient 1), 6.8 (patient 2), and 11% (patient 3). Since patients 1 and 2 had identified dystrophin-gene deletions these results were obtained using monoclonal antibodies specific to epitopes coded by the deleted exons. Donor dystrophin was absent in the control sites. Patient 3 had exon duplication and thus specific donor-dystrophin detection was not possible. However, there were fourfold more dystrophin-positive myofibers in the cell-grafted than in the control site. Donor-dystrophin transcripts were detected by RT-PCR (using primers reacting with a sequence in the deleted exons) only in the cell-grafted sites in patients 1 and 2. Dystrophin transcripts were more abundant in the cell-grafted than in the control site in patient 3. Therefore, significant dystrophin expression can be obtained in the skeletal muscles of DMD patients following specific conditions of cell delivery and immunosuppression.

13/01/04: Suppression of Nonsense Mutations in the Dystrophin Gene by a Suppressor tRNA Gene  

Kiselev, A. V.; Ostapenko, O. V.; Rogozhkina, E. V.; Kholod, N. S. ; Seit-nebi, A. S. ; Baranov, A. N.; Lesina, E. A.; Ivashchenko, T. E.; Sabetskii, V. A.; Shavlovskii, M. M. ; Rechinsky, V. O. ; Kisselev, L. L. ; Baranov, V. S. - from Russia

Molecular Biology. 36(1):30-33, January/February 2002

Nonsense mutations in the dystrophin gene are the cause of Duchenne muscular dystrophy (DMD) in 10-15% of patients. In such an event, one approach to gene therapy for DMD is the use of suppressor tRNAs to overcome the premature termination of translation of the mutant mRNA. We have carried out cotransfection of the HeLa cell culture with constructs containing a suptRNA gene (pcDNA3suptRNA) and a marker LacZ gene (pNTLacZhis) using their polymer VSST-525 complexes. It was found that the number of cells producing [beta]-galactosidase depends inversely on the dose of the suptRNA gene. A single in vivo injection of the construct providing for expression of the suptRNAochre gene into mdx mouse muscle resulted in the production of dystrophin in 2.5% of fibers. This suggests that suppressor tRNAs are applicable in gene therapy for hereditary diseases caused by nonsense mutations

13/01/04: The Current State and Prospects of the Gene Therapy of Duchenne Muscular Dystrophy Worldwide and in Russia

Baranov, V. S. ; Baranov, A. N. ; Zelenin, A. V. from Russia

Russian Journal of Genetics. 37(8):868-875, August 2001

Failure of drug therapy of Duchenne muscular dystrophy (DMD) stimulated intense search for adequate methods of gene therapy (GT) which would ensure effective delivery of the dystrophin (D) gene, its long-term persistence in transfected cells, and its expression in muscle fibers. The main results of the experimental GT of DMD with the use of viral and nonviral delivery of the D gene into muscles of biological models are discussed. Delivery of a mini-gene of D with a specific muscle promoter using a modified adenoassociated virus is currently the most promising method, which will soon be available for clinical trials. The main results of the studies on the DMD GT in Russia are summarized. The results of experiments on genetic transfection of mdx mice with marker genes and various constructions with the D gene are outlined. The genes are delivered into muscles by means of gene gun, electroporation, viral oligopeptides, liposomes, microspheres, lactoferine, and other nonviral vehicles. It is emphasized that consolidation of funds and efforts of all Russian laboratories dealing with gene and cell therapy of DMD are necessary to complete the experiments and start clinical trials.

13/01/04: Expression of Dystrophin in Duchenne Muscular Dystrophy Patients after Myoblast Transplantation  

Shishkin, S. S.; Terekhov, S. M.; Krokhina, T. B.; Shakhovskaya, N. I.; Podobedova, A. N.; Lyannaya, G. F. ; Tarasov, V. I.; Ovchinnikov, V. I.; Krakhmaleva, I. N.; Zakharov, S. F.; Ershova, E. S.; Limborska, S. A.; Pogoda, T. V.; Zotikov, E. A.; Kut'ina, P. M.; Tarksh, M. A.; Sukhorukov, V. S.; Gerasimova, N. L.  from Russia

Based on originally designed technique of myoblast cultivation and in accordance with the approved by the Russian Ministry of Health "one muscle treatment" protocol of myoblast transplantation to the Duchenne muscular dystrophy patients, the first in Russia clinical trial of this gene correction method was carried out. Immunologically related myoblast cultures (30 to 90 million cells per patient) were injected after all preliminary procedures into tibialis anterior muscles of four boys selected from a group of volunteer recipients (Duchenne muscular dystrophy patients) based on the analysis of a number of surface antigens in donor-recipient pairs. The condition of the patients remained satisfactory during the whole period of post-transplantation follow-up (from 6 months to 1.5 years). Six months after myoblast transplantation the presence of donor DNA or dystrophin synthesis was demonstrated in muscle biopsies of three out of four patients. This result confirms efficacy and safety of the procedure used.


13/01/04: The Golden Freeway: a preliminary evaluation of a pilot study advancing information technology as a social intervention for boys with Duchenne muscular dystrophy and their families

Soutter, Jennifer; Hamilton, Neil BA Dip BA; Russell, Peter BA; Russell, Chris ; Bushby, Kate ; Sloper, Patricia; Bartlett, Kim 

Health & Social Care in the Community. 12(1):25-33, January 2004

Established information technology was used in an attempt to reduce social isolation by providing each family who had a child with Duchenne muscular dystrophy with a personal computer, and e-mail and Internet connectivity. Seventy-four of the 88 families in the north of England (i.e. Cumbria, Durham, Northumberland, Teesside, and Tyne and Wear) with a boy with Duchenne muscular dystrophy who was diagnosed before January 2000 had the equipment installed. Evaluations of equipment usage and parental perceptions of the project were carried out at 3 and 12 months post-installation. Results from quantitative and qualitative interviews with parents indicated that benefits accrued to the families and to the boys themselves: family relationships can be extended, and the boys can acquire a degree of independence which, according to parents' views, can boost self-confidence and self-esteem. As hoped, social isolation was felt to have been reduced, and an occupation, interest and enjoyment provided. The greatest use of the computer was for schoolwork with siblings sharing in this. Cost proved to be a problem for a number of families. For the project team, there were unexpected aspects: creating an e-community was more difficult than anticipated, more training was required and not all families would ever use the equipment to its fullest. However, families did emphasise the value of the project as a way of opening the world for their sons.

10/01/04: IN PRESS  (FEBS Letters: 28018 (2004) 1-5) - Creatine increases IGF-I and myogenic regulatory factor mRNA in C2C12 cells

Magali Louis, Ronald Van Beneden, Mischael  Dehoux, Jean Paul Thissen, Marc Francaux;

Abstract: Addition of creatine to the diferentiation medium of  C2C12 cells leads to hypertrophy of the myotubes. To investigate  the implication of insulin-like growth factor I (IGF-I) and myogenic regulatory factors (MRFs) in this hypertrophy, their  mRNA levels were assessed during the first 72 h of diferentiation. Creatine significantly increased the IGF-I mRNA level over the whole investigated period of time, whereas the MRF mRNA levels were only augmented at precise moments, suggesting a general activation mechanism for IGF-I and a specifically regulated mechanism for MRF transcription. Our results suggest therefore that creatine-induced hypertrophy of C2C12 cells is at least partially mediated by overexpression of IGF-I and MRFs.

10/01/04: Susceptibility to sarcomere injury induced by single stretches of maximally activated muscles of mdx mice

07/01/04 - Targeting the Immune System to Improve Ventilatory Function in Muscular Dystrophy

07/01/04 - A possible role of tryptase in angiogenesis in the brain of mdx mouse, a model of Duchenne muscular dystrophy  

07/01/04 - University of Rochester Awarded $6.5 Million to Study Efficacy OF rhIGF-I/rhIGFBP-3, SomatoKine, in the Treatment of Myotonic Dystrophy

Why not in DMD patients? Enhanced dystrophic progression in mdx mice by exercise and beneficial effects of taurine and insulin-like growth factor-1

Free IGF-1 Administration

rhIGFBP-3 Administration

01/01/04 - ViaCell, Amgen in cell therapies deal

 

 

2003 NEWS (JANUARY- DECEMBER)

 

2002 NEWS (JANUARY- DECEMBER)