New Videos
2002 NEWS 2003 NEWS 2004 NEWS 2005 NEWS
2007 NEWS
DECEMBER
19 - (Am. J. Roentgenol., Jan 2008; 190: W8 - W12)Three-Point Technique of Fat Quantification of Muscle Tissue as a Marker of Disease Progression in Duchenne Muscular Dystrophy: Preliminary Study
OBJECTIVE. Clinical trials involving patients with Duchenne muscular dystrophy are hindered by the lack of suitable objective end points. The purpose of this study was to examine whether muscle lipid infiltration measured with the three-point Dixon MRI technique has value as a marker of disease severity.
SUBJECTS AND METHODS. Disease severity in nine boys (mean age, 8.6 ± 2.7 years) with Duchenne muscular dystrophy was determined with the functional ability scale of Brooke and associates. Functional scores were compared with strength measurements obtained by manual testing of muscles of the lower extremities, knee extensor strength measured with an isokinetic dynamometer, and muscle fat percentage in the quadriceps and hamstrings determined with the three-point Dixon MRI technique.
RESULTS. MRI measurements of fat infiltration had stronger correlation (p < 0.05) with functional grade than did measurements obtained with manual muscle testing (p = 0.07) or quantitative strength measured with the isokinetic dynamometer (p = 0.54). Muscle fat percentage did not correlate with strength measurements from manual or dynamometer muscle testing but increased with age in subjects with Duchenne muscular dystrophy.
CONCLUSION. Muscle adiposity values obtained with three-point Dixon MRI are accurate in assessment of disease severity in patients with Duchenne muscular dystrophy. Because they are not influenced by patient effort or examiner variability, these measurements are more objective and reproducible than measurements of muscle strength.
13 - (Chest. 132(6):1977-1986, December 2007) American College of Chest Physicians Consensus Statement on the Respiratory and Related Management of Patients With Duchenne Muscular Dystrophy Undergoing Anesthesia or Sedation
Birnkrant, David J.; Panitch, Howard B.; Benditt, Joshua O.; Boitano, Louis J. ; Carter, Edward R. MD, ; Cwik, Valerie A. ; Finder, Jonathan D. ; Iannaccone, Susan T. ; Jacobson, Lawrence E. ; Kohn, Gary L. ; Motoyama, Etsuro K. ; Moxley, Richard T. ; Schroth, Mary K. ; Sharma, Girish D. ; Sussman, Michael D. - USA
This statement on the management of patients with Duchenne muscular dystrophy (DMD) undergoing procedural sedation or general anesthesia represents the consensus opinion of a multidisciplinary panel convened under the auspices of the American College of Chest Physicians. Expert recommendations on this subject are needed for several reasons. First, patients with DMD have an increased risk of complications when they undergo sedation or general anesthesia. In addition, due to improved cardiopulmonary therapies, patients with DMD are experiencing an unprecedented duration of survival. As a result, it is more common for them to require procedures involving sedation or general anesthesia. The risks related to anesthesia and sedation for DMD patients include potentially fatal reactions to inhaled anesthetics and certain muscle relaxants, upper airway obstruction, hypoventilation, atelectasis, congestive heart failure, cardiac dysrhythmias, respiratory failure, and difficulty weaning from mechanical ventilation. This statement includes advice regarding the highly interrelated areas of respiratory, cardiac, GI, and anesthetic management of patients with DMD undergoing general anesthesia or procedural sedation. The statement is intended to aid clinicians involved in the care of patients with DMD and to be a resource for other stakeholders in this field, including patients and their families. It is an up-to-date summary of medical literature regarding this topic and identifies areas in need of future research.
13 - (Anaesthesia. 63(1):89-91, January 2008) Acute liver failure following therapeutic paracetamol administration in patients with muscular dystrophies.[Report]
Pearce, B.; Grant, I. S. - UK
Clinically significant liver damage in patients taking
therapeutic doses of paracetamol is very rare. We report two cases of fulminant
hepatic failure caused by therapeutic (4 g.day-1) paracetamol administration on
our Intensive Care Unit. Both patients had a
muscular dystrophy and presented
with a chest infection on a background of endstage neuromuscular
respiratory failure. We also noted one further similar case in the literature
and suggest a relationship between muscular
dystrophy and paracetamol-induced
hepatotoxicity. In this report we discuss in detail possible mechanisms that may
account for this apparent association, which include altered pharmacokinetics,
reduced glutathione stores, malnutrition and hypoxic injury.
12 - (Cell Stem Cell, December - 2007) Restoration of Human Dystrophin Following Transplantation of Exon-Skipping-Engineered DMD Patient Stem Cells into Dystrophic Mice
12 - PPMD Annual Connect Conference, Philadelphia, 12 - 14 July 2007 - Günter Scheuerbrandt report
8 - Cognitive and Psychological Profile of Males With Becker Muscular Dystrophy
NOVEMBER
14 - (47th Annual Meeting of American Society of Cell Biology, December 2007)
The Potential Influence of NF-kappaB Down Regulation on the Activity of the PI3/AkT Pathway in Dystrophic (mdx) Skeletal Muscle
B. Lee,1 G. W. Millman,1 E. C. Turin,1 A. Samadi,2 C. G. Carlson1; 1Physiology, A.T. Still University of Health Sciences, Kirksville, MO, 2Biochemistry, A.T. Still University of Health Sciences, Kirksville, MO
Recent evidence indicating that treatments to reduce the activity of the NF-kappaB pathway may be useful in treating Duchenne and Becker muscular dystrophy (Carlson et al., Neurobiology of Disease, 20 (3):719-730, 2005; Messina et al., Experimental Neurology 198:234-241, 2006; Acharyya et al., J. Clin. Invest. 117, 889-901, 2007) provides the rationale for ongoing experiments which are directed at identifying specific phenotypic endpoints for assessing drug efficacy using the mdx mouse model for Duchenne muscular dystrophy. Consideration of the central importance of the PI3kinase/Akt pathway in promoting the growth and regeneration of skeletal muscle, however, suggests that a combined treatment to reduce the activity of the NF-kappaB pathway and increase PI3kinase/Akt activation may be an appropriate therapy for this group of diseases. In order to investigate this possibility, we have begun to examine the status of the PI3kinase/Akt pathway in costal diaphragm cytosolic extracts obtained from mdx mice treated either acutely or chronically with two inhibitors of the NF-kappaB pathway, pyrrolidine dithiocarbamate (PDTC; 50 mg/kg) and sulfasalazine (SS; 100 mg/kg). Western blots of phosphorylated and total Akt indicate that a single injection of either of these two agents does not modify the activity of the PI3kinase/Akt pathway. Initial experiments suggest that daily treatment of mdx mice with PDTC for a period of at least 30 days may activate the PI3kinase/Akt pathway, but that corresponding treatment with sulfasalazine has no effect on the proportion of phosphorylated Akt. Although it is currently unclear whether chronic treatment with these established NF-kappaB inhibitors effectively down regulates nuclear NF-kappaB activation in dystrophic skeletal muscle, these preliminary results suggest that chronic treatment with NF-kappaB inhibitors that reduce IkappaB-alpha kinase activity (IKK) may be used in conjunction with PI3kinase/Akt activation to judiciously enhance muscle regeneration in dystrophic skeletal muscle.
Evaluation of the Effectiveness of a Mast Cell Degranulation Inhibitor in Dystrophic mdx Mice
D. D. Araujo,1,2 F. S. M. Pires,2 T. T. Fuzisaki,2 J. C. S. Bizario,2 M. R. Costa1,2; 1Cellular Molecular Biology, University of São Paulo, Ribeirão Preto, Brazil, 2Medicine School, University of Ribeirão Preto, Ribeirão Preto, Brazil
Duchenne muscular dystrophy (DMD) is characterized by progressive muscle degeneration which results from the absence of dystrophin. The dystrophin deficient mdx mouse, the most widely used animal model for DMD, shows milder phenotype that can be intensified by compulsory physical activity. Inflammatory response and immune cells contribute to muscle degeneration and/or regeneration. Mast cells are recruited to the injury sites and liberate mediators that increase collagen production, attract other inflammatory cells and intensify tissue damage. Olopatadine, an H1-histamine antagonist and a mast cell degranulation inhibitor, decreases Ca2+ influx and the liberation of histamine, tryptase, leukotrienes and prostaglandins. In this study, we evaluated the effect of 10 mg/kg/day olopatadine in male mdx mice submitted to physical activity (20 minutes of treadmill running at 20 cm/s, 3 times a week, during 5 weeks). To characterize the experimental groups (treated and untreated) before (4 week old mdx) and after (9 week old mdx) of the physical activity program, we used the following parameters: i) measurement of body weight and serum creatine kinase; ii) qualitative and quantitative histopathological analyses of gastrocnemius and diaphragm (Evans Blue Dye infiltration and H&E staining to evaluate myofibers morphology, the presence of inflammatory infiltrates, peripherally and centrally nucleated myofibers, and grouped regenerating myofibers). The results showed that the 9 week old olopatadine treated mice presented significant reduction in the CK levels and amelioration of the muscular condition. We detected significant reduction in the number of myofibers with sarcolemma injury but no difference in the number of centrally nucleated myofibers. The analysis of the individual values suggests a trend to reduction in the inflammatory infiltrate area and in the degeneration/regeneration ratio. These data suggest that the inhibition of mast cell is beneficial to retard the dystrophinopathy progress and can be considered as an option to clinical trials for DMD.
13 - Kiwi company's medical breakthrough
http://www.orico.co.nz/muscle_therapeutic_development_program/
http://www.orico.co.nz/intellectual_property_and_publications/
10 - (Journal of the Neurological Sciences, 2007) Connective tissue growth factor is overexpressed in muscles of human muscular dystrophy
Guilian Sun, Kazuhiro Haginoya, Yanling Wu , Yoko Chiba , Tohru Nakanishi ,Akira Onuma , Yuko Sato e, Masaharu Takigawa , Kazuie Iinuma , Shigeru Tsuchiya - Japan
The detailed process of how dystrophic muscles are replaced by fibrotic tissues is unknown. In the present study, the immunolocalization and mRNA expression of connective tissue growth factor (CTGF) in muscles from normal and dystrophic human muscles were examined with the goal of elucidating the pathophysiological function of CTGF in muscular dystrophy. Biopsies of frozen muscle from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy, congenital muscular dystrophy, spinal muscular atrophy, congenital myopathy were analyzed using anti-CTGF polyclonal antibody. Reverse transcription-polymerase chain reaction (RT-PCR) was also performed to evaluate the expression of CTGF mRNA in dystrophic muscles. In normal muscle, neuromuscular junctions and vessels were CTGF-immunopositive, which suggests a physiological role for CTGF in these sites. In dystrophic muscle, CTGF immunoreactivity was localized to muscle fiber basal lamina, regenerating fibers, and the interstitium. Triple immunolabeling revealed that activated fibroblasts were immunopositive for CTGF and transforming growth factor-beta1 (TGF-beta1). RT-PCR analysis revealed increased levels of CTGF mRNA in the muscles of DMD patients. Co-localization of TGF-beta1 and CTGF in activated fibroblasts suggests that CTGF expression is regulated by TGF-beta1 through a paracrine/autocrine mechanism. In conclusion, TGF-beta1-CTGF pathway may play a role in the fibrosis that is commonly observed in muscular dystrophy.
8 - (Prostaglandins, Leukotrienes and Essential Fatty Acids, 2007) Effects of inhibitors of the arachidonic acid cascade on primary muscle culture from a Duchenne muscular dystrophy patient
I. Gáti O., Danielsson, T. Betmark, J. Ernerudh, K. Öllinger and N. Dizdar - Sweden
The aim of this study was to elucidate the mechanisms of action for potential targets of therapeutic intervention related to the arachidonic acid cascade in muscular dystrophy. Primary cultures from a Duchenne patient were used to study the expression of dystrophin-1, utrophin, desmin, neonatal myosin heavy chain (MHCn) and Bcl-2 during inhibition of phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX). Hypo-osmotic treatment was applied in order to trigger Ca2+ influx and PLA2 activity. Inhibition of PLA2 and LOX with prednisolone and nordihydroguaiaretic acid (NDGA) caused a semi-quantitative increase of utrophin and Bcl-2-, and a dose-dependent, quantitative increase of desmin expression, an effect that was augmented by hypo-osmotic treatment. Our results indicate that LOX inhibitors, similarly to corticosteroids, can be beneficial in the treatment of muscular dystrophies
6 - (American Heart Association Annual Meeting, 2007) 1) Minor Myocardial Damage and LV Dysfunction in Patients with Duchenne Muscular Dystrophy -The Preventive Efficacy of Carvedilol on Plasma Cardiac Troponin I-
Background: Cardiac dysfunction is one of the major prognostic factors in patients with Duchenne muscular dystrophy (DMD). Minor myocardial damage assessed by plasma cardiac troponin I (cTnI) is often observed in patients with DMD. However, it is unclear that how the minor myocardial damage occurs to which patient with DMD and how it relates to LV dysfunction. Therefore, we assessed the hypothesis that minor myocardial damage is associated with LV dysfunction, the evaluation of plasma cTnI helps the prediction of LV functional deterioration, and carvedilol prevents elevation of plasma cTnI in patients with DMD.
Methods: Plasma cTnI were repeatedly (every 3 months) measured for 2 years and LV function was assessed by echocardiography in 58 patients with DMD. Carvedilol (2.5–5 mg/day) was orally administered for a year to the patients who have shown plasma cTnI elevation (positive cTnI, cut off 0.06ng/mL).
Results: There were 3 differential groups regarding the progression rate of LV systolic dysfunction, i.e. rapid (19% of total, LVEF < 50% in their 10th), slow (50% of total, LVEF > 50% in their 20 –30th), and unchanged group (31% of total, LVEF < 50% in their 20 –30th). The episode of positive cTnI was observed in 27 (46%) of total patients with DMD. LVEF was lower in patients with positive cTnI than that with negative cTnI (42 ± 2 vs. 52 ± 2%, p < 0.05). Positive cTnI was observed in all patients in rapid group, 84% of patients in slow group, and only 6% of patients in unchanged group. Fourteen differential dystrophin gene mutations were recognized in 48 patients but they were not associated with those 3 differential groups or patients with positive cTnI. Administration of carvedilol in 13 patients (LVEF 40 ± 3) decreased the cTnI detection rate (from 44 ± 5% to 26 ± 10%, p < 0.05), while it was unchanged in 14 patients (LVEF 41 ± 3) without carvedilol treatment (from 44 ± 7% to 39 ± 6%) during same observation period.
Conclusions: The elevation of plasma cTnI was associated with LV systolic dysfunction in patients with DMD. The prediction of LV dysfunction in patients with DMD may be feasible with combinations of age, LVEF, and plasma cTnI elevation. Carvedilol could be a new therapeutic strategy to prevent minor myocardial damage in patients with DMD.
Background: Delta-Sarcoglycan (SGCD) is a member of the dystrophin-associated glycoprotein complex. Mutations may result in isolated dilated cardiomyopathy or limb-girdle muscle dystrophy 2F with variable cardiac involvement. A potential gene therapeutic approach requires an efficient myocardial gene transfer. AAV vectors are suitable for cardiac gene transfer. Novel AAV serotypes such as AAV-8 or -9 even enable a systemic gene transfer in rodents. Aim of our study was to establish a vector for efficient systemic cardiac gene transfer and its subsequent use to prevent heart failure by expressing the SGCD cDNA in SGCD knock out mice.
Material and Methods: 1011 genomic particles of AAV-8 and -9 vectors harboring a luciferase reporter gene under control of the CMV-enhanced myosin light chain promoter were intravenously injected into adult NMRI mice (n=6 and n=10, respectively). After 4 weeks, reporter activities were determined in representative organs. Analogous, 2x1011 AAV-9 SGCD and AAV-9 EGFP vectors were intravenously injected in SGCD knock out mice (n=9 and n=7, respectively). Cardiac function (fraction of shortening) was assed by echocardiography at the beginning and the end of the study after 6 months. Running distances were measured using voluntary wheel running.
Results: Reporter gene transfer with AAV-9 vectors resulted in increased cardiac luciferase activities compared to AAV-8 (3.8x108 ±4.4x108 relative light units [RLU]/mg protein versus 0.10x108 ±0.08x108 RLU/mg protein, p=0.05) with increased specificity. In comparison to EGFP controls, AAV-9 delta-sarcoglycan gene transfer resulted in a significant increase in running distance and a significant decrease in decline in fraction of shortening (67.6% to 65.0% versus 69.9% to 58.1%; p=0.04). Immunohistochemical analyses in AAV-9 SGCD treated knock-out mice revealed a transmural reconstitution of more than 90% of cardiomyocytes.
Conclusion: Intravenous injections of AAV-9 SGCD vectors enable an efficient transmural cardiac gene transfer in adult mice and prevent deterioration of left ventricular function in SGCD knock out mice. Therefore, this vector system may be suitable for validation of novel targets for cardiac diseases
BACKGROUND: Duchenne Muscular Dystrophy (DMD), an x-linked
myopathy, is characterized by progressive cardiac dysfunction and
myocardial fibrosis late in the disease process. We hypothesized that
left ventricular myocardial peak circumferential strain (
cc)
abnormalities would exist in DMD prior to global systolic functional
abnormalities regardless of age or left ventricular ejection fraction
(EF).
METHODS: We evaluated 33 DMD males undergoing clinical cardiac MRI. Comparison was made to 13 age-matched healthy volunteers. Standard imaging included short-axis cine stack, cine myocardial tagging and myocardial delayed enhancement (MDE). Cardiac functional analysis was performed using Medis MASS software. Tagged images of only the mid-LV were analyzed using HARP software. For analysis, DMD males were subdivided by age: < or > 10 years. All subjects < 10 years had normal EF (>55%); none exhibited MDE. Subjects >10 years were divided by MDE status and EF (>55% or <55%). Student’s t-test was used to test for differences between groups.
RESULTS: DMD subjects with normal EF had abnormal
cc
at an early age (<10 years) compared to control subjects (p< 0.05).
DMD subjects >10 years with normal EF had further decline in =cc
compared to younger DMD boys (p<0.05). There was further decline with
age in =cc in subjects with lower EF (p<0.05) without MDE.
In the oldest males studied with MDE and reduced EF,
cc
was even lower (figure).
CONCLUSIONS: Myocardial strain abnormalities are prevalent in the early stages of DMD existing in the setting of normal EF and progressing with advances in age. Such strain analysis may provide an early marker to guide the efficacy of preventive or gene therapy in DMD.
|
2 - (Journal of Electromyography and Kinesiology, 2007) Evaluation of plantar flexion contracture contribution during the gait of children with Duchenne muscular dystrophy
Nathaly Gaudreailt, Denis Gravel and Sylvie Nadeau - Canada
Because of extensor weakness, children with Duchenne muscular dystrophy (DMD) maintain internal flexion moments at the joints of the lower extremities when they walk. We believe that at the ankle, the plantar flexion moments caused by contractures may contribute significantly to the production of the net ankle flexion moment during the gait in these children. The goal of the present study is to quantify ankle plantar flexion passive moments that may be associated with the presence of flexion contractures and to estimate their contribution to the net moment during the gait of children with DMD. Kinematic and kinetic parameters were collected during gait of eleven subjects with DMD. Ankle plantar flexion passive moments were also measured experimentally during the same session. Fourteen control children participated in the study in order to have normal reference values. The presence of ankle plantar flexion contractures in children with DMD was reflected by a rigidity coefficient obtained at a common moment of −7 Nm that was higher for these children (0.75 Nm/° vs. 0.48 Nm/°; p < 0.05). The relative passive moment contribution to the net plantar flexion moments was higher for the children with DMD at the end of the lengthening phase of the plantar flexors (25% vs. 18%; p < 0.05). We believe that the passive moments can compensate for the presence of progressive muscle weakness in the children with DMD and help these children with gait.
2 - (Am. J. Pathol., Nov 2007; 171: 1576 - 1587) Transgenic Overexpression of ADAM12 Suppresses Muscle Regeneration and Aggravates Dystrophy in Aged mdx Mice
Muscular dystrophies are characterized by insufficient
restoration and gradual replacement of the skeletal muscle by fat and
connective tissue. ADAM12 has previously been shown to alleviate the
pathology of young dystrophin-deficient mdx mice, a
model for Duchenne muscular dystrophy. The observed effect of ADAM12 was
suggested to be mediated via a membrane-stabilizing up-regulation of
utrophin,
7B
integrin, and dystroglycans. Ectopic ADAM12 expression in normal
mouse skeletal muscle also improved regeneration after freeze injury,
presumably by the same mechanism. Hence, it was suggested that ADAM12
could be a candidate for nonreplacement gene therapy of Duchenne
muscular dystrophy. We therefore evaluated the long-term effect of
ADAM12 overexpression in muscle. Surprisingly, we observed loss of
skeletal muscle and accelerated fibrosis and adipogenesis in 1-year-old
mdx mice transgenically overexpressing ADAM12 (ADAM12+/mdx
mice), even though their utrophin levels were mildly elevated
compared with age-matched controls. Thus, membrane stabilization was
not sufficient to provide protection during prolonged disease.
Consequently, we reinvestigated skeletal muscle regeneration in
ADAM12 transgenic mice (ADAM12+) after a knife cut lesion
and observed that the regeneration process was significantly impaired.
ADAM12 seemed to inhibit the satellite cell response and delay
myoblast differentiation. These results discourage long-term
therapeutic use of ADAM12. They also point to impaired regeneration
as a possible factor in development of muscular dystrophy.
OCTOBER
27 - (JCB, 2007;179(2):305) Necdin mediates skeletal muscle regeneration by promoting myoblast survival and differentiation
Daniela Deponti, Stéphanie François, Silvia Baesso, Clara Sciorati, Anna Innocenzi, Vania Broccoli, Françoise Muscatelli, Raffaella Meneveri, Emilio Clementi, Giulio Cossu, and Silvia Brunelli - Italy
Regeneration of muscle fibers that are lost during pathological muscle degeneration or after injuries is sustained by the production of new myofi bers. An important cell type involved in muscle regeneration is the satellite cell. Necdin is a protein expressed in satellite cell–derived myogenic precursors during perinatal growth. However, its function in myogenesis is not known. We compare transgenic mice that overexpress necdin in skeletal muscle with both wild-type and necdin null mice. After muscle injury the necdin null mice show a considerable defect in muscle healing, whereas mice that overexpress necdin show a substantial increase in myofiber regeneration. We also find that in muscle, necdin increases myogenin expression, accelerates differentiation, and counteracts myoblast apoptosis. Collectively, these data clarify the function and mechanism of necdin in skeletal muscle and show the importance of necdin in muscle regeneration.
26 - (Circulation Research, October 2007) Twenty-One-Month-Old Carrier Mice by Mosaic Dystrophin Expression or Complementary Dystrophin/Utrophin Expression
Brian Bostick ;
A cure for dystrophin-deficient muscular dystrophy requires treating both skeletal muscle and the heart. Whereas mosaic dystrophin expression has been shown to protect skeletal muscle, controversy exists over whether mosaic expression is protective in the heart. We have shown recently that mosaic dystrophin expression prevents stress-induced heart damage in young carrier mice. Although an interesting finding, the clinical relevance remains to be established because young dystrophin-null mdx mice do not have heart disease. On the other hand, heart failure has been reported in human carriers. To resolve this mouse/human discrepancy, we evaluated the cardiac phenotype in 21-month-old mdx, carrier, and normal mice. We found dilated cardiomyopathy in old mdx mice but not in age-matched carrier mice. All anatomical parameters and physiological assay results (ECG and closed-chest Millar catheter) were within the normal range in old carrier mice. Focal myocardial inflammation was found in a small fraction of old carrier mice, but it had no major impact on heart function. Dobutamine stress revealed a near normal hemodynamic profile except for a marginal reduction in systolic pressure in old carrier mice. Immunostaining and Western blot showed dystrophin expression in 50% cardiomyocytes in old carrier mice. Interestingly, utrophin was upregulated in dystrophin-negative heart cells in carrier mice. In summary, we have provided the first clear-cut evidence that dilated cardiomyopathy in old mdx mice was prevented by mosaic dystrophin expression or complementary dystrophin/utrophin expression. Our results raise the hope for ameliorating dystrophic cardiomyopathy through partial gene and/or cell therapy.
20 - (Chest Meeting Abstracts, Oct 2007; 132: 607c - 608) INCIDENCE AND OUTCOMES OF CARDIOPULMONARY RESUSCITATION IN PATIENTS WITH END-STAGE DUCHENNE MUSCULAR DYSTROPHY
Garey Noritz David J. Birnkrant - USA
PURPOSE: Although technological cardiopulmonary therapies, such as noninvasive ventilation (NIV), have increased life span for patients (pts) with Duchenne muscular dystrophy (DMD), the disease remains fatal. Pts with end-stage DMD who forgo “do not resuscitate” directives may be partially resuscitated after near-fatal events, exposing them to the risk of brain damage. PURPOSE: To assess the frequency of attempted resuscitation among pts with DMD in our clinic who experienced cardiopulmonary arrest, and to describe their outcomes.
METHODS: Retrospective chart review.
RESULTS: Ten of our pts with DMD died during the time period 9/1/03-4/1/07. Mean age at death _/- SD: 20.7 _/- 2.7 years. Three of the 10 pts had unmeasurable vital capacities and were dependent on NIV 24 hrs/day. Mean vital capacity of the remaining 7 pts: 0.57 _/- 0.53 liters. All pts were prescribed daily NIV but 4 pts used NIV infrequently. All pts had cardiomyopathy. Four pts were in congestive heart failure. Two pts had cardiac defibrillators. After cardiopulmonary arrest, five of the 10 pts underwent resuscitation attempts. No pt was successfully resuscitated. Four of the 5 pts died immediately. One pt was partially resuscitated, experienced brain damage, and died after being taken off the ventilator by his family.
CONCLUSION: A significant proportion of our pts with end-stage DMD who experienced cardiopulmonary arrest underwent attempted resuscitation. None of the resuscitation attempts was successful. Lack of “do not resuscitate” advance directives exposed these pts to the risk of partial resuscitation and brain damage.
CLINICAL IMPLICATIONS: Pts with advanced DMD are increasingly cared for by cardiologists, pulmonologists, and intensivists, whose focus may be technologically oriented. We speculate that use of technological therapies like assisted ventilation and defibrillators among such pts may produce an unrealistically optimistic view of their prognosis, causing resistance to advance “do not resuscitate” directives, even among pts with end-stage disease. Studies are needed regarding how to reconcile palliative and technological therapies to optimize end-of-life care among pts with severe DMD.
18 - Distinctive patterns of microRNA expression in primary muscular disorders
17 - (Neurology, October 2007) Albuterol increases lean body mass in ambulatory boys with Duchenne or Becker muscular dystrophy
C. L. Skura,
Background: Albuterol is a beta-2 agonist that has been demonstrated to increase muscle strength in studies in animals and humans. Based on a pilot study of extended-release albuterol Repetabs in children with dystrophinopathies, the authors conducted a randomized, double-blind, placebo-controlled study with a crossover design.
Methods: Fourteen boys with Duchenne or Becker muscular dystrophy, 6 to 11 years old, completed two treatment periods (albuterol and placebo), 12 weeks each, separated by a 12-week washout period. As the albuterol Repetab formulation was no longer available, an alternate extended release albuterol was used (Volmax, 12 mg per day). Outcome measurements included 1) lean body mass, 2) fat mass, 3) isometric knee extensor and flexor moments, 4) manual muscle testing, and 5) timed functional tests.
Results: Lean body mass was significantly higher for subjects following albuterol treatment compared to placebo treatment, while fat mass was significantly lower. No differences were found in isometric knee moments or manual muscle tests. Time to run/walk 30 feet was improved following albuterol.
Conclusions: Short-term treatment with extended release albuterol may increase lean body mass, decrease fat mass, and improve functional measures in patients with dystrophinopathies. However, the significant change in strength of specific muscle groups found in the pilot study was not observed in the present study. These findings may be attributed to differences in the drug release and kinetics between Repetab and Volmax formulations as they affect the concentration of available beta-2 receptors on the muscle cell surface differently.
13 - Safety and Efficacy Study of Antisense Oligonucleotides in Duchenne Muscular Dystrophy
12 - (European Journal of Paediatric Neurology 11 (2007) 337-40) CINRG pilot trial of oxatomide in steroid-naıve Duchenne muscular dystrophy
Gunnar M. Buyse,, Nathalie Goemans, Erik Henricson, Alejandro Jara, Marleen van den Hauwe, Robert Leshner, Julaine M. Florence, Jill E. Mayhew, Diana M. Escolar - USA
The authors report a pilot open-label two-center therapeutic trial of oxatomide in 14 steroid-naive DMD boys aged 5–10 years. Comparison of linear evolutions between 3 months medication-free lead-in periods and 6 months treatment periods showed no significant differences in quantitative (QMT) and manual (MMT) measurements of muscle strength and timed functional tests. A modest mitigation of strength deterioration over time cannot be excluded.
12 - (Heart, October - 2007) Life expectancy and death from cardiomyopathy amongst carriers of Duchenne and Becker muscular dystrophy in Scotland
Objectives To assess life expectancy and cardiovascular mortality in carriers of Duchenne and Becker Muscular Dystrophy.
Design Family pedigrees of individuals affected with these conditions, held by the 4 genetics centres in Scotland, were examined to identity a cohort of definite carriers. Electronic death registration data, held by the General Register Office for Scotland were used to identify death certificates of carriers who had died, to obtain age at death and cause of death. Survival and mortality data were obtained for the general population for comparison.
Patients 397 definite carriers in 202 pedigrees were identified from which 94 deaths were identified by record linkage to death certificates.
Main outcome measures Observed numbers surviving to certain ages and numbers dying of cardiac causes were compared with expected numbers calculated from general population data. Results: There were no significant differences between observed and expected numbers surviving to ages 40-90. The standardised mortality ratio for the 371 carriers alive in 1974 was 0.53 (95% confidence interval 0.32-0.82).
Conclusions Whereas female carriers may have clinical features of cardiomyopathy, this study does not suggest that this is associated with reduced life expectancy or increased risk of cardiac death. Routine cardiac surveillance of obligate carriers is therefore probably unnecessary.
9 - (Paediatrics and Child Health, Volume 17, Issue 10, October 2007, Pages 419-420) Bone profile and vitamin D level in children with Duchenne muscular dystrophy (DMD)
M Sundaram, S Spinty - Alder Hey Childrens Hospital, Liverpool
Introduction: Approximately 1500 children are affected by DMD in the UK at any one time. Patients with DMD are at increased risk of long-bone and vertebral fractures. Reduced physical activity, a calcium-poor diet and low vitamin D levels are risk factors for reduced bone mineral density. Low vitamin D levels increase the risk of osteopenia. Inadequate nutritional intake of the precursor vitamin D2 and lack of sun exposure to aid conversion to the active form vitamin D3 in the skin lowers vitamin D levels. Sun exposure is often reduced in wheelchair-dependent patients with DMD. Steroids have been shown to slow down disease progression in patients with DMD. It is now recommended that all children with DMD should be offered steroids at a time when their functional abilities plateau. Osteoporosis is a side-effect of steroid treatment and further increases the risk of bone fractures. We set out to evaluate bone profiles (calcium, phosphate and alkaline phosphate) and vitamin D levels in children and adolescents with DMD, whose samples were taken at Alder Hey Hospital. Methods: Bone profiles and vitamin D2 and D3 levels were reviewed in 46 patients with DMD. Results: None of the patients studied showed clinical or biochemical evidence of rickets. Vitamin D3 levels were low for the seasonal variation in 17 out of 46 (36.9%) patients – 6 out of the 23 (26%) ambulant patients and 11 out of the 23 non-ambulant (47.8%) patients were vitamin D deficient. A number of children were vitamin D deficient at diagnosis. The mean age of the patients with low vitamin D levels was 11.6 years (range 7–17 years). Conclusions: Vitamin D level should be checked routinely at diagnosis and at regular intervals in all children with DMD. Deficiency should be appropriately treated to optimise bone health and reduce the risk of fractures.
5 - Autologous transplantation of muscle-derived CD133+ stem cells in Duchenne muscle patients
4 - Use of Weekly Alendronate to Treat Osteoporosis in Boys with Muscular Dystrophy
4 - (NEUROSCI BIOBEHAV REV, 2007) Duchenne muscular dystrophy: A cerebellar disorder?
CYRULNIK, S.C., and V.J. Hinton - USA
Duchenne muscular dystrophy (DMD) is a genetic disorder that is often associated with cognitive deficits. These cognitive deficits have been linked to the absence of dystrophin, a protein product which is normally found in multiple tissues throughout the body. In the current paper, we argue that it is the absence of dystrophin in the cerebellum that is responsible for the cognitive deficits observed. We begin by reviewing data that document structural and functional abnormalities in the brains of individuals with DMD and mdx mice. We briefly review the cognitive deficits associated with DMD, and then present neuroimaging and neuropsychological evidence to indicate that the cerebellum is involved in the same aspects of cognition that are impaired in children with DMD. It is our contention that brain pathways in the cerebellum (e.g., cerebro-cerebellar loops) which develop without dystrophin may result in altered brain function presenting as cognitive deficits in DMD.
SEPTEMBER
24 - (Faseb J, 2007) Transgenic expression of a myostatin inhibitor derived from follistatin increases skeletal muscle mass and ameliorates dystrophic pathology in mdx mice
Myostatin is a potent negative regulator of skeletal muscle growth. Therefore, myostatin inhibition offers a novel therapeutic strategy for muscular dystrophy by restoring skeletal muscle mass and suppressing the progression of muscle degeneration. The known myostatin inhibitors include myostatin propeptide, follistatin, follistatin-related proteins, and myostatin antibodies. Although follistatin shows potent myostatin-inhibiting activities, it also acts as an efficient inhibitor of activins. Because activins are involved in multiple functions in various organs, their blockade by follistatin would affect multiple tissues other than skeletal muscles. In the present study, we report the characterization of a myostatin inhibitor derived from follistatin, which does not affect activin signaling. The dissociation constants (Kd) of follistatin to activin and myostatin are 1.72 nM and 12.3 nM, respectively. By contrast, the dissociation constants (Kd) of a follistatin-derived myostatin inhibitor, designated FS I-I, to activin and myostatin are 64.3 µM and 46.8 nM, respectively. Transgenic mice expressing FS I-I, under the control of a skeletal muscle-specific promoter showed increased skeletal muscle mass and strength. Hyperplasia and hypertrophy were both observed. We crossed FS I-I transgenic mice with mdx mice, a model for Duchenne muscular dystrophy. Notably, the skeletal muscles in the mdx/FS I-I mice showed enlargement and reduced cell infiltration. Muscle strength is also recovered in the mdx/FS I-I mice. These results indicate that myostatin blockade by FS I-I has a therapeutic potential for muscular dystrophy
23 - (2007 Annual Meeting of The American Society of Human Genetics) Antisense-mediated exon 51 skipping restores local dystrophin expression in muscle of Duchenne muscular dystrophy patients.
A. Aartsma-Rus1, J.J.G.M. Verschuuren2,
A.A.M. Janson3, G. Platenburg3, G-J.B. van Ommen1,
J.C.T. van Deutekom1,3 1) Department of Human Genetics, Leiden
University Medical Center, Leiden, the Netherlands; 2) Department of Neurology,
Leiden University Medical Center, Leiden, the Netherlands; 3) Prosensa B.V.
Leiden, the Netherlands.
Antisense-mediated reading frame restoration is currently one of the most
promising therapeutic approaches for Duchenne muscular dystrophy (DMD). In this
approach, antisense oligoribonucleotides (AONs) induce specific exon skipping
during pre-mRNA splicing. They have been successful in repairing the disrupted
open reading frame accompanied by the generation of internally deleted,
partially functional Becker-like dystrophins. Proof of concept has been achieved
in cultured muscle cells from patients, as well as in the mdx mouse model.
As an essential step towards broad clinical studies and future applications, we
here evaluated the effect of a single, intramuscular dose of DMD AON PRO051.
Four DMD patients with different mutations were included on basis of eligible
mutation, adequate condition of the target muscle, and positive in vitro
PRO051 skip-response. A dose of 0.8 mg PRO051, without any excipient, was
injected locally into tibialis anterior muscle and a biopsy was taken after 4
weeks. Exon 51 skipping on RNA level and restoration of dystrophin expression
was confirmed for each patient, as demonstrated by RT-PCR, immunohistochemical
and western blot analyses. Dystrophin levels were ~10% of wild type levels,
except for one patient who suffered from a severe loss of muscle fibers and
profound signs of dystrophy in his tibialis muscle . The AON was well tolerated
and did not provoke serious adverse events in any of the patients. Our results
provide a strong basis for subsequent studies on systemic treatment of DMD
patients.
21 - Genetic treatments in muscular dystrophies
19 - 18 years experience with mechanical ventilation in patients with Duchenne muscular dystrophy
16 - (The 2nd Congress of Asian Society for Pediatric Research - 2007)
1) TREATMENT OF DUCHENNE MUSCULAR DYSTROPHY BY AMINOGLYCOSIDES
Lai PS, Lim PPD, Tay SKH, Low PS - Dept of Paediatrics, National University of Singapore
Background
Duchenne muscular dystrophy (DMD) is an X-linked disorder caused by absence of dystrophin protein. A novel genetic approach for therapy of DMD patients carrying nonsense mutations has been proposed using aminoglycoside treatment. Aminoglycosides are postulated to suppress nonsense mutations by translational readthrough of stop codons, thus resulting in protein expression. The aim of this study is to investigate the efficacy of four aminoglycosides (gentamicin, paromomycin, tobramycin and G418), and to develop cell-free and cell-based assays for measuring readthroughs.
Methods
The cell-free system involved in vitro transcription-translation reactions to assay the radioisotope-labeled protein produced after aminoglycoside treatment. The cell-based system was designed by cloning mutational constructs carrying readthrough cassettes of three types of stop codons, UAA, UAG and UGA. The constructs were transfected into HEK cell lines treated with aminoglycosides and assayed by FITC fluorescence.
Results
For the cell-free assays, optimal readthroughs of the UAG stop codon was observed ranging from 5-20% (2-10 mcg/ml gentamicin), 20-40% (20-400 mcg/ml paromomycin), 6-14% (80-1000 mcg/ml tobramycin) and 2-20% (2-1000 mcg/ml G418). For the cell-based assays, the readthroughs were lower, with maximum values of only up to 3%. The optimal concentrations for the aminoglycosides were : 0.75–1.0 mg/ml gentamicin, 1–2.5 mg/ml paromomycin, > 2.4 mg/ml tobramycin, 0.15- 2.4 mg/ml G418.
Conclusions
The nonsense mutation most susceptible to aminoglycoside suppression is UGA stop codon. All aminoglycosides resulted in some levels of readthroughs. Differences in clinically effective readthrough levels between the two assay systems highlight the need for caution when comparing results using different assays.
2) Purification of Satellite Cells From Mouse ES Cells
Hsi Chang1, Toshio Heike1, Momoko Yoshimoto2, Katsutsugu Umeda1, Tatsutoshi Nakahata1
1Kyoto University, Department of Pediatrics, 2Wells Center For Pediatric Research, Indianapolis, IN, USA
Duchene muscular dystrophy (DMD) is well known as one of the progressive muscle diseases which decline the quality of life (QOL). Although many researchers search for new possible and trial therapies, but there is no conclusive clinical therapy that could improve the patients’ QOL till nowadays. For the solution of these problems, myogenic cell transplantation has been reported as a new approach recently. Before the establishment of myogenic cell transplantation therapy, the identification and purification of muscle specific stem cells called satellite cells could be indispensable. So far, there have been many studies related to the isolation and characterization of satellite cells. However, the differentiation and isolation of satellite cells from mouse embryonic stem (ES) cells has not yet been reported and it is still hard to specifically induce myogenic cells from ES cells. Here, we report a newly established method that effectively induces a cell subpopulation with satellite cell properties from mouse ES cells. This is the first report of satellite cells induced from mouse ES cells and these findings could pave a path for therapeutic use of ES cells for muscular disorders.
3) Comprehensive mutation analysis of the dystrophin gene in Japanese Duchenne and Becker muscular dystrophies
Yasuhiro Takeshima, Kazuto Ishibashi, Atsushi Nishiyama, Zhujun Zhang, Tran Thi Hoai Thu, Yasuaki Habara, Mariko Yagi, Masafumi Matsuo - Kobe University Graduate School of Medicine, Department of Pediatrics
[Background] Duchenne and Becker muscular dystrophy (DMD/BMD) are caused by mutations in the dystrophin gene. Mutation analysis of the dystrophin gene is indispensable not only to provide proper clinical information but to apply the molecular therapies, which depend on the type of mutation in each case. However, the large size of dystrophin gene (3000kb and 79 exons) hampers the detection of small mutations including nonsense, frame shift, and splice site mutations. To clarify the responsible mutations of all cases, a comprehensive mutation analysis of the dystrophin gene employing not only genomic DNA but mRNA was performed in Japanese DMD/BMD. [Patients and Methods] A total of 431 cases from unrelated 355 Japanese families of DMD/BMD were recruited. Gross gene arrangements were detected by Southern blotting or PCR methods using genomic DNA as template, and small mutations were analyzed by RT-PCR or direct sequence method using genomic DNA or cDNA as template. [Results] Among 355 families, 221 (62%) and 23 (6%) had large deletion and duplication encompassing at least one exon, respectively. X-chromosome abnormality was disclosed in 3 families. In the 108 remaining families, 61 nonsense, 23 frame shift, and 22 splice site mutations were identified. It is noteworthy that 67% of them are novel mutations. In two cases, however, no mutation was detected.[Conclusions] In this study we succeeded to reveal the responsible gene mutations in 99.4% of the analyzed cases, and the present result disclosed the highest mutation detection rate in DMD/BMD.
15 - (Spine, 32(20), 2007, 2278-2283) Tranexamic Acid Diminishes Intraoperative Blood Loss and Transfusion in Spinal Fusions for Duchenne Muscular Dystrophy Scoliosis
Shapiro, Frederic ; Zurakowski, David P; Sethna, Navil F - USA
Study Design. Retrospective review of intraoperative blood loss and blood replacement.
Objective. We compared intraoperative blood loss and blood replacement during spinal fusion surgery for scoliosis in Duchenne muscular dystrophy (DMD) performed with and without the synthetic antifibrinolytic agent tranexamic acid (TXA).
Summary of Background Data. High levels of intraoperative blood loss are widely documented in DMD patients undergoing posterior spinal fusion for scoliosis. The effect of the antifibrinolytic agent tranexamic acid on decreasing the blood loss has not been studied in a large group of DMD patients.
Methods. All 56 DMD patients underwent posterior spinal fusion with the same technique using 2 rods and multiple sublaminar wires. TXA was not used in 36 patients and was used in 20. In the respective groups, the age at surgery (14 vs. 13.9 years), the preoperative deformity (45° vs. 51°), the mean number of levels fused (14.3 vs. 14.7), and the mean surgical times (446 minutes vs. 459 minutes) were similar. TXA dose was 100 mg/kg in solution over 15 minutes before incision followed by an infusion of 10 mg/kg per hour during surgery. Standardized measurements of intraoperative blood loss were used and calculated to compare total amount of blood loss in milliliters per patient and blood loss as a percentage in relation to estimated blood volume [estimated blood loss (EBL)/estimated blood volume (EBV) × 100]. The EBV was calculated to be 70 mL/kg (body weight).
Results. Mean blood loss with TXA was 1944 ± 789 mL (range, 760–4000 mL) and without TXA was 3382 ± 1795 mL (range, 600–9580 mL) (P < 0.001). Blood loss with TXA decreased by 42% compared with those not treated with TXA. Accounting for patient weight and estimated blood volume, mean % blood loss with and without TXA was 47% ± 28% versus 112% ± 67% (P < 0.001). This physiologic indicator shows that blood loss with TXA decreased by 58% compared with those patients not treated with TXA. TXA was also found to reduce blood loss after accounting for surgical time. No hypercoagulation or other complications from TXA therapy were obs-erved. The reduced blood loss in TXA-treated patients translated into decreased blood transfusions. Transfusion of homologous whole blood and packed red blood cells in the TXA group was decreased by 46% compared with the no TXA group (mean levels, 512 ± 470 mL vs. 955 ± 718 mL), and transfusion of autologous cell saver blood was decreased by 42% in the TXA group (mean levels, 419 ± 235 mL vs. 728 ± 416 mL).
Conclusion. TXA significantly reduces both intraoperative blood loss and the need for homologous transfusion of whole blood and packed red blood cells in DMD patients undergoing posterior spinal fusion for scoliosis.
15 - CTS-IPITA-IXA 2007 Joint Conference – Abstracts - Minneapolis – September 15–20, 2007
13 - 6th Monaco Round Table report, held on June 23rd, 2007
12 - Dystrophin levels as low as 30% are sufficient to avoid muscular dystrophy in the human
11 - (Am J Physiol Heart Circ Physiol 293: H1969-H1977, 2007) The role of reactive oxygen species in the hearts of dystrophin-deficient mdx mice
Duchenne muscular dystrophy (DMD) is caused by deficiency of the cytoskeletal protein dystrophin. Oxidative stress is thought to contribute to the skeletal muscle damage in DMD; however, little is known about the role of oxidative damage in the pathogenesis of the heart failure that occurs in DMD patients. The dystrophin-deficient (mdx) mouse is an animal model of DMD that also lacks dystrophin. The current study investigates the role of the antioxidant N-acetylcysteine (NAC) on mdx cardiomyocyte function, Ca2+ handling, and the cardiac inflammatory response. Treated mice received 1% NAC in their drinking water for 6 wk. NAC had no effect on wild-type (WT) mice. Immunohistochemistry experiments revealed that mdx mice had increased dihydroethidine (DHE) staining, an indicator of superoxide production; NAC-treatment reduced DHE staining in mdx hearts. NAC treatment attenuated abnormalities in mdx cardiomyocyte Ca2+ handling. Mdx cardiomyocytes had decreased fractional shortening and decreased Ca2+ sensitivity; NAC treatment returned mdx fractional shortening to WT values but did not affect the Ca2+ sensitivity. Immunohistochemistry experiments revealed that mdx hearts had increased levels of collagen type III and the macrophage-specific protein, CD68; NAC-treatment returned collagen type III and CD68 expression close to WT values. Finally, mdx hearts had increased NADPH oxidase activity, suggesting it could be a possible source of increased reactive oxygen species in mdx mice. This study is the first to demonstrate that oxidative damage may be involved in the pathogenesis of the heart failure that occurs in mdx mice. Therapies designed to reduce oxidative damage might be beneficial to DMD patients with heart failure.
11 - (Arch Neurol. 2007;64:1236-1241) Gene Therapy for Duchenne Muscular Dystrophy: Expectations and Challenges
Duchenne muscular dystrophy is a debilitating X-linked disease with limited treatment options. We examined the possibility of moving forward with gene therapy, an approach that demonstrates promise for treating Duchennemuscular dystrophy. Gene therapy is not limited to replacement of defective genes but also includes strategies using surrogate genes with alternative but effective means of improving cellular function or repairing gene mutations. The first viral-mediated gene transfer for any muscle disease was carried out at Columbus Children's Research Institute and Ohio State University for limb girdlemuscular dystrophy type 2D, and the first viral-mediated trial of gene transfer for Duchenne muscular dystrophy is under way at the same institutions. These studies, consisting of intramuscular injection of virus into a single muscle, are limited in scope and represent phase 1 clinical trials with safety as the primary end point. These initial clinical studies lay the foundation for future studies, providing important information about dosing, immunogenicity, and viral serotype in humans. This article highlights the challenges and potential pitfalls as the field advances this treatment modality to clinical reality.
Myogenic precursor cell (MPC) transplantation is a good strategy to introduce dystrophin expression in muscles of Duchenne muscular dystrophy (DMD) patients. Insulin-like growth factor (IGF-1) promotes MPC activities, such as survival, proliferation, migration and differentiation, which could enhance the success of their transplantation. Alternative splicing of the IGF-1 mRNA produces different muscle isoforms. The mechano growth factor (MGF) is an isoform, especially expressed after a mechanical stress. A 24 amino acids peptide corresponding to the C-terminal part of the MGF E domain (MGF-Ct24E peptide) was synthesized. This peptide had been shown to enhance the proliferation and delay the terminal differentiation of C2C12 myoblasts. The present study showed that the MGF-Ct24E peptide improved human MPC transplantation by modulating their proliferation and differentiation. Indeed, intramuscular or systemic delivery of this synthetic peptide significantly promoted engraftment of human MPCs in mice. In vitro experiments demonstrated that the MGF-Ct24E peptide enhanced MPC proliferation by a different mechanism than the binding to the IGF-1 receptor. Moreover, MGF-Ct24E peptide delayed human MPC differentiation while having no outcome on survival. Those combined effects are probably responsible for the enhanced transplantation success. Thus, the MGF-Ct24E peptide is an interesting agent to increase MPC transplantation success in DMD patients.
AUGUST
28 - Quadrupling Muscle Mass in Mice by Targeting TGF-ß Signaling Pathways
28 - (Neuromuscular Disorders, 2007) Workshop report: Behavior patterns in Duchenne muscular dystrophy: Report on the Parent Project Muscular Dystrophy behavior workshop 8–9 of December 2006, Philadelphia, USA LIBRARY
James Poysky - USA
Introduction
Eighteen participants representing clinicians, scientists, parents, industry, and public health agencies involved in the assessment and treatment of children with Duchenne muscular dystrophy (DMD) from Australia, Canada, the Netherlands, the UK and the USA met in Philadelphia on December 8–9, 2006 to attend a workshop addressing behavioral issues among children and young adults with DMD. The workshop, sponsored by Parent Project Muscular Dystrophy (PPMD–USA), was organized in response to parent and clinician concerns regarding behavior associated with DMD, and its subsequent impact on patient and family quality of life. For the purposes of clarification, in this report the term “behavior” is defined as readily observable external actions and responses, as well as internal affective/emotional states. The aims of the workshop were to (1) evaluate current findings and determine whether characteristic behaviors occur among boys and young men with DMD, (2) examine etiological factors contributing to behavior patterns in DMD, and (3) develop recommendations for research and intervention strategies.
DMD is a genetic disorder occurring in approximately one in 3300 live male births. Mutations in the dystrophin gene result in an absence of dystrophin or a non-functional dystrophin protein. The different types and locations of the mutation are highly variable across individuals, and it is unclear to what extent this has an impact on the phenotype. However, in all cases progressive muscle degeneration ensues, with morbidity typically occurring in the second or third decade of life. Muscle degeneration has understandably been the primary focus of research and treatment, and much less emphasis has been placed on behavioral functioning. There is, however, emerging evidence of central nervous system (CNS) involvement resulting in cognitive and neurobehavioral disorders. In addition, because of the debilitating and fatal nature of the disorder, significant psychosocial factors must also be considered. Behavioral functioning has a significant impact on quality of life and can also directly affect medical care, in particular as it is related to things like treatment adherence and behavioral response to medication. Research to date is limited, and studies have typically focused on one component of physiological, cognitive, or emotional functioning in DMD. The complex interactions between these various factors have not been clearly defined. As such, greater understanding of these interactions is necessary for appropriate patient care and treatment planning.
25 - (Neuromuscular Disorders, 2007) Case report: Myoglobinuria in boys with Duchenne muscular dystrophy on corticosteroid therapy
P. Garrood, M. Eagle, P.E. Jardine, K. Bushby and V. Straub - UK
Myoglobinuria is a recognised complication of Duchenne muscular dystrophy (DMD), but has only once been reported in ambulant boys on corticosteroid therapy [Dubowitz V, Kinali M, Main M, Mercuri E, Muntoni F. Remission of clinical signs in early Duchenne muscular dystrophy on intermittent low-dosage prednisolone therapy. Eur J Paediatr Neurol 2002;6(3):153–9.]. We present three prednisolone-treated boys with myoglobinuria and in two cases this was recurrent. All three showed improved motor performance in response to the introduction of corticosteroids. The greater activity of steroid-treated individuals may place their dystrophin-deficient muscles under greater mechanical stress, predisposing to further muscle fibre damage and consequent myoglobinuria. Families and physicians need to have an increased awareness of this possibility and of the appropriate management of myoglobinuria.
25 - Videofluorographic assessment of swallowing function in patients with Duchenne muscular dystrophy
25 - Utrophin up-regulation by an artificial transcription factor in transgenic mice
22 - (Pediatric Anesthesia,2007) Duchenne muscular dystrophy: an old anesthesia problem revisited LIBRARY
Jason Hayes, Francis Veyckemans, Bruno Bissonnette - Canada e Belgium
Patients with Duchenne and Becker muscular dystrophy suffer from a progressive deterioration in muscle secondary to a defect in the dystrophin gene. As such, they are susceptible to perioperative respiratory, cardiac and other complications, such as rhabdomyolysis. Inhalational anesthetic agents have been implicated as a cause of acute rhabdomyolysis that can resemble malignant hyperthermia (MH). This article reviews perioperative ‘MH-like’ reactions reported in muscular dystrophy patients and groups them into three categories according to clinical presentation. The etiology and underlying pathophysiological process responsible for these reactions is discussed and recommendations are proposed for the safe anesthetic management of these patients.
13 - (Brain & Development 29:596-500,2007) Cardiac troponin I for accurate evaluation of cardiac status in myopathic patients
Tsuyoshi Matsumura , Toshio Saito, Harutoshi Fujimura, Susumu Shinno - Japan
Background: Brain natriuretic peptide (BNP) and left ventricular ejection fraction (LVEF) are standard indexes for cardiac function. However, they can not reveal myocardial damage directly and they often remain normal even in advanced cardiomyopathy in immobilized patients. Myocardial markers such as MB type of creatine kinase (CK-MB), heart-type fatty acid binding protein (HFABP) and cardiac troponins are expected to evaluate active myocardial degeneration. However, their availabilities in these patients have not been examined yet. Methods: Participants were 129 patients with dystrophinopathies; 100 Duchenne muscular dystrophy (DMD), 25 Becker muscular dystrophy (BMD) and 4 DMD/BMD carriers. Various serological cardiac indexes, including CK-MB, H-FABP, cardiac troponin I (cTnI), BNP and LVEF were measured and statistical analysis was done. Results: CK-MB and HFABP was highly associated with creatine kinase (CK). On the contrary, cTnI, BNP and LVEF were independent from CK. In DMD, relatively high cTnI values were observed in patients with motor ability of rowing wheelchair and in their second decade. BNP and LVEF was strongly correlated. However, cTnI was independent from LVEF and only weak correlation could be detected between cTnI and BNP. Conclusion: cTnI had been proven to be expressed in myocardium exclusively. Our results also certified that cTnI can assess cardiac degeneration independently from skeletal muscle degeneration and is practical index even in myopathic patients. Our findings also suggested that cardiac degeneration was preceded to functional impairment in many cases. It indicated that cTnI enable us to detect early stage of cardiac degeneration and initiate intervention at proper stage.
11- 2007 Annual Conference Powerpoint Presentations
JULY
31 - (Growth Hormone & IGF Research, 2007) Muscular dystrophy-related quantitative and chemical changes in adenohypophysis GH-cells in golden retrievers
A.R. de Lima , J.R. Nyengaard , A.A.L. Jorge , J.C.C. Balieiro , C. Peixoto , E.T. Fioretto , C.E. Ambrosio f, M.A. Miglino , M. Zatz , A.A.C.M. Ribeiro - Brazil
Duchenne muscular dystrophy (DMD) is a recessive X-linked lethal condition which affects a boy in every 3300 births. It is caused by the absence of dystrophin, a protein occurring especially within the musculoskeletal system and in neurons in specific regions of the central nervous system (CNS). Growth hormone (GH) inhibition is believed to decrease the severity of DMD and could perhaps be used in its treatment. However, the underlying pathological mechanism is not known. The golden retriever muscular dystrophy dog (GRMD) represents an animal model in the study of DMD. In this paper we investigated the morphological aspects of the adenohypophysis as well as the total number and size of GH-granulated cells using design-based stereological methods in a limited number of dystrophic and healthy golden retrievers. GH-cells were larger (32.4%) in dystrophic dogs than in healthy animals (p = 0.01) and they occupied a larger portion (62.5%) of the adenohypophysis volume (p = 0.01) without changes in either adenohypophysis volume (p = 0.893) or total number of GH-granulated cells (p = 0.869). With regard to ultrastructure, granulated cells possessed double-layer electron-dense granules which were evenly distributed in the cytosol. Furthermore, these granules in dystrophic animals occupied a larger proportion of GH-granulated cell volume (66.9%; p = 0.008) as well as of all GH-cells in the whole pars distalis of adenohypophysis (77.3%; p = 0.035), albeit IGF-1 serum concentration was lower in severe cases. This suggests difficulties in the GH secretion that might possibly be associated to dystrophin absence. In contrast to earlier reports, our data suggest that a lower IGF-1 concentration may be more related to a severe, as opposed to a benign, clinical form of muscular dystrophy.
31 - (International Journal of Cardiology,2007) Letter to the Editor: Holter electrocardiogram should be systematic in Duchenne muscular dystrophy
A. Fayssoil - France
Duchenne muscular dystrophy (DMD) is due to mutations in the dystrophin gene on chromosome Xp21.1. Dystrophin is a sarcolemmal protein which binds actin to extra cellular matrix. A deficiency in dystrophin leads to breakdown of muscle membrane and muscular alteration
[1]. The disease is clinically characterized by proximal weakness and wasting, leading to loss of ambulation by 12 years of age. The heart is affected to various degrees, depending on the stage of the disease. The most common cardiac abnormality in DMD is dilated cardiomyopathy. Conduction system disease and tachyarrhythmias may occur in some patients. Death occurs in early adulthood secondary to respiratory or cardiac failure [2], even if recent advances in the use of inspiratory and expiratory muscle aids have greatly reduced the risk of pulmonary morbidity and mortality rates [3].The typical initial manifestation of cardiac involvement in DMD is sinus tachycardia [1]. Cardiac involvement is due to progressive replacement of the cardiomyocytes and the Purkinje system by connective tissue or fat [1]. Impairment of cardiac autonomic function in patients with DMD is well known. Kirchmann found sinus tachycardia in 26% and reduced heart rate variability in 51% [4]. In human cardiac purkinje fibers, immunocytochemical staining showed that dystrophin was localised to the membrane surface of the purkinjer fiber [5]. The cardiac rhythm abnormalities play a significant role in morbidity and mortality in this disease [6]. Supraventricular ectopy or couplets are reported to indicate increasing severity of arrhythmia with the progression of disease [7]. 33% of DMD patients had ventricular premature beats in a study including 45 Duchenne muscular dystrophy patients without congestive heart failure and followed up for 3 years [8]. Patients who died suddenly were more likely to have had documented complex ventricular arrhythmias (6 of 9; 66%) [8].Shortened PQ interval and prolonged QT interval are also reported. In a controlled series including 328 DMD patients, 62% had conduction abnormalities like shortened PQ interval and prolonged QT interval by age 10 years [9]. Conduction system disease was also reported. Indeed, complete atrioventricular block was reported in the literature in 1997 [10]. Holter electrocardiogram should be systematic periodically in the following of the DMD patients because of possible occurring conduction system disease and tachyarrhythmias. According to American paediatrics recommendations, periodic Holter monitoring should be considered for patients with demonstrated cardiac dysfunction [2].References
[1] Finsterer J, Stollberger C. The heart in human dystrophinopathies cardiology. 2003; 99: 1-19.
[2] American Academy of Pediatrics Section on Cardiology and Cardiac Surgery. Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy. Pediatrics Dec 2005;116(6):1569–73.
[3] Bach JR, Ishikawa Y, Kim H. Prevention of pulmonary morbidity for patients with Duchenne muscular dystrophy. Chest 1997;112:1024–8. [4] Kirchmann C, Kececioglu D, korinthenberg R, Dittrich S. Echocardiographic and electrographic finding of cardiomyopathy in Duchenne and Becker-Kiener muscular dystrophies. Pedriatr Cardiol janv-feb 2005;26(1):66–72.
[5] Bies RD, Friedman D, Roberts R, Perryman MB, Caskey CT. Expression and localization of the dystrophin in human cardiac purkinje fibers. Circulation 1992;86(1):147–53.
[6] Corrado G, Lissoni A, Beretta S, et al. Prognostic value of electrocardiograms, ventricular late potentials, ventricular arrhythmias, and left ventricular systolic dysfunction in patients with Duchenne muscular dystrophy. Am J Cardiol 2002;89:838–41.
[7] Yanagisawa A, Miyagawa M, Yotsukura M, et al. The prevalence and prognostic significance of arrhythmias in Duchenne muscular dystrophy. Am Heart J 1992;124:1244–50
[8] Chenard AA, Becane HM, Tertrain F, de Kermadec JM, Weiss YA. Ventricular arrhythmia in Duchenne muscular dystrophy: prevalence, significance and prognosis. Neuromuscul Disord May 1993;3(3):201–6. [9] Nigro G, Comi L, Politan L, Brain RJ. The incidence and evolution of cardiomyopathy in Duchenne muscular dystrophy. Int J Cardiol 1990;26:271–7.
[10] Takano N, Honke K, Hasui M, Ohno I, Takemura H. A case of pacemaker implantation for complete atrioventrivular block associated with Duchenne muscular dystrophy. No to Hattatsu Nov 1997;29 (6):476–80.
Mechanism of action of ACE inhibitors and Angiotensin II blockers
27 - Episodic hypoxia exacerbates respiratory muscle dysfunction in DMD(mdx) mice
K. Bushby , R. Griggs , on behalf of the MSG/ENMC FOR DMD trial study group
Eighteen participants from 6 countries met in Naarden from 22nd–24th October 2006 to review the proposed plan for an international trial to find the optimal steroid regimes in Duchenne Muscular Dystrophy (DMD)(trial acronym FOR DMD). At the 124th ENMC international workshop in April 2004 the need for a trial of corticosteroid dosage regimes in DMD was highlighted by clinicians in the field as well as patient organisations, reflecting a high level of dissatisfaction with the inconsistency of use of corticosteroid and the profusion of different steroid regimes in use in clinics across the world. The conclusion of that workshop was that a trial of different corticosteroid regimes was indicated, and subsequently an international steering committee was established. This committee prepared a protocol for an international trial of steroid dosage regimes in DMD which received funding from the NIH for a planning grant to develop a full trial grant application. The aim of the current workshop was to bring together members of the trial writing group with representatives of investigators from the different countries taking part in the trial to allow a full review of the protocol and prepare the final version of the protocol and manual of operations to be submitted as a full grant to NIH in early 2007.
Table included in this article:
25 - Arrhythmia follow-up of children and adolescents with neuromuscular diseases
24 - (American Heart Journal, 2007) Perindopril preventive treatment on mortality in Duchenne muscular dystrophy: 10 years' follow-up
Denis Duboc; Christophe Meune, Bertrand Pierre, Karim Wahbi, Bruno Eymard, Annick Toutain, Carole Berard, Guy Vaksmann, Simon Weber, Henry-Marc Becane - France
Background: Duchenne muscular dystrophy (DMD), an X-linked disorder due to lack of dystrophin, is associated with muscle weakness and myocardial dysfunction. Although preliminary data support the efficacy of angiotensin-converting enzyme inhibitors on left ventricular (LV) function, our aim was to examine the long-term impact of a preventive treatment with perindopril on mortality in children with DMD.
Methods: Patients with DMD between the ages of 9.5 and 13 years presenting with normal LV ejection fraction were included in this prospective study. They were randomly assigned for 3 years to perindopril, 2 to 4 mg (group 1), or placebo (group 2) in a double-blind protocol, followed by open-label treatment with perindopril for up to 10 years. Survival rate at 10 years in each group is reported.
Results: There were 28 patients assigned to group 1 and 29 to group 2. Baseline characteristics were similar in both groups. At the end of the 10 years' follow-up period, survival status was available for all included patients: 26 (92.9%) of 28 patients in group 1 were alive at 10 years versus 19 (65.5%) of 29 in group 2 (P = .02). Kaplan-Meier cumulative survival was significantly lower in group 2 than in group 1 (P = .013).
Conclusion: Early initiation of treatment with perindopril is associated with a lower mortality in patients with DMD with normal LV ejection fraction at study entry.
14 - Low bone mineral density and decreased bone turnover in Duchenne muscular dystrophy
12 - New Target For Muscular Dystrophy Drug Therapy Found
ERF Silences Extrasynaptic Utrophin by N-Box-mediated Repression in Skeletal Muscle
7 - Antisense-induced exon skipping for duplications in Duchenne muscular dystrophy
Myostatin (Mst) is a negative regulator of skeletal muscle in humans and animals. It is moderately expressed in the heart of sheep and cattle, increasing considerably after infarction. Genetic blockade of Mst expression increases cardiomyocyte growth. We determined whether Mst overexpression in the heart of transgenic mice reduces left ventricular size and function, and inhibits in vitro cardiomyocyte proliferation. Young transgenic mice overexpressing Mst in the heart (Mst transgenic mice (TG) under a muscle creatine kinase (MCK) promoter active in cardiac and skeletal muscle, and Mst knockout (Mst (–/–)) mice were used. Xiscan angiography revealed that the left ventricular ejection fraction did not differ between the Mst TG and the Mst (–/–) mice, when compared with their respective wild-type strains, despite the decrease in whole heart and left ventricular size in Mst TG mice, and their increase in Mst (–/–) animals. The expected changes in cardiac Mst were measured by RT-PCR and western blot. Mst and its receptor (ActRIIb) were detected by RT-PCR in rat H9c2 cardiomyocytes. Transfection of H9c2 with plasmids expressing Mst under muscle-specific creatine kinase promoter, or cytomegalovirus promoter, enhanced p21 and reduced cdk2 expression, when assessed by western blot. A decrease in cell number occurred by incubation with recombinant Mst (formazan assay), without affecting apoptosis or cardiomyocyte size. Anti-Mst antibody increased cardiomyocyte replication, whereas transfection with the Mst-expressing plasmids inhibited it. In conclusion, Mst does not affect cardiac systolic function in mice overexpressing or lacking the active protein, but it reduces cardiac mass and cardiomyocyte proliferation.
JUNE
30 - New Genetic Test Developed At Emory Advances Detection And Diagnosis Of Muscular Dystrophy
21 - Morpholino Oligomer-Mediated Exon Skipping Averts the Onset of Dystrophic Pathology in the mdx Mouse
18 - (Biology of Blood and Marrow Transplantation, 2007) Hematopoietic Cell Transplantation Directly into Dystrophic Muscle Fails to Reconstitute Satellite Cells and Myofibers
Christian S. Kuhr, Marilena Lupu, Rainer Storb - USA
We sought to determine whether wild-type hematopoietic cell transplantation directly into muscle could restore dystrophin expression in a relevant preclinical canine model of Duchenne muscular dystrophy. In recipients rendered tolerant to their dog leukocyte antigen-matched unaffected littermates through hematopoietic stem cell transplantation, intramuscular injection of donor marrow cells produced no evidence of dystrophin expression, and clonal analysis of satellite cells failed to reveal any donor contribution.
16 - The role of reactive oxygen species in the hearts of dystrophin-deficient (mdx) mice
16 - Chronic respiratory failure in patients with neuromuscular diseases: diagnosis and treatment LIBRARY
9 - Potential of oligonucleotide-mediated exon-skipping therapy for Duchenne muscular dystrophy
8 - Living with muscular dystrophy: health related quality of life consequences for children and adults
7 - (Free Radical Biology and Medicine; 43(1):145-54) Low intensity training decreases markers of oxidative stress in skeletal muscle of mdx mice
Jan J. Kaczor, , Julie E. Hall, Eric Payne and Mark A. Tarnopolsky - Canada
Reactive oxygen species may contribute to the pathogenesis
of muscular dystrophy. High intensity exercise clearly
induces muscle damage in mdx mice; however, the effects of low intensity
exercise training (LIT) on mdx muscle are less clear. We examined the
effect of LIT on markers of oxidative stress (malondialdehyde and protein
carbonyls), antioxidant (superoxide dismutase, catalase, and glutathione
peroxidase), and mitochondrial (2-oxoglutarate dehydrogenase and cytochrome
oxidase) enzymes in skeletal muscle of mdx and wild-type mice. Mdx
and wild-type mice were allocated to LIT and sedentary groups. Malondialdehyde
levels were higher in white muscle from sedentary mdx as compared to both
sedentary and LIT wild-type mice (P < 0.001). Protein carbonyl content
was higher in white and red muscle of mdx versus wild-type mice (P < 0.05).
LIT was associated with lower levels of malondialdehyde and protein carbonyls in
white muscle of mdx mice (decreased 38 and 44%, P < 0.001 and P < 0.01,
respectively). Antioxidant and mitochondrial enzyme activities were higher in
white muscle of mdx than in wild-type mice (P < 0.05). LIT in
mdx mice induced physiological adaptation resulting in lower levels of
markers of oxidative stress that were not different than those from wild type.
These results are of relevance for therapeutic exercise in patients with
dystrophinopathy where exercise prescription remains controversial.
7 -
Herpes
Simplex Virus VP22 Enhances Adenovirus-Mediated Microdystrophin Gene Transfer to
Skeletal Muscles in Dystrophin-Deficient (mdx) Mice
5 - Effects of a CRF2R agonist and exercise on mdx and wildtype skeletal muscle
2 - The role of corticosteroids in muscular dystrophy: A critical appraisal
MAY
25 - Passive in vivo elastography from skeletal muscle noise
23 - (Am J Physiol Regul Integr Comp Physiol, 2007 ) Reversal by relaxin of altered ileal spontaneous contractions in dystrophic (mdx) mice through a nitric oxide-mediated mechanism
Altered nitric oxide (NO) production/release is involved in gastrointestinal motor disorders occurring in dystrophic (mdx) mice. Since the hormone relaxin (RLX) can up-regulate NO biosynthesis, its effects on spontaneous motility and NO synthase (NOS) expression in the ileum of dystrophic (mdx) mice were investigated. Mechanical responses of ileal preparations were recorded in vitro via force-displacement transducers. Evaluation of the expression of NOS isoforms was performed by immunohistochemistry and Western blot. Normal and mdx mice were distributed into three groups: untreated, RLX-pretreated, vehicle-pretreated. Ileal preparations from the untreated animals showed spontaneous muscular contractions whose amplitude was significantly higher in mdx than in normal mice. Addition of RLX, alone or together with L-arginine, to the bath medium depressed the amplitude of the contractions in the mdx mice, thus re-establishing a motility pattern typical of the normal mice. The NOS inhibitor L-NNA or the guanylate cyclase inhibitor ODQ reversed the effects of RLX. In RLX-pretreated mdx mice, the amplitude of spontaneous motility was reduced, thus resembling that of the normal mice, and NOS II expression in the muscle coat was increased in respect to the vehicle-pretreated mdx animals. These results indicate that RLX can reverse the altered ileal motility of mdx mice to a normal pattern, likely by up-regulating NOS II expression and NO biosynthesis in the ileal smooth muscle.
18 - (Acta Histochemica, 2007) Fibre-related nitric oxide synthase (NOS) in Duchenne muscular dystrophy
K. Punkt, S. Schering, M. Fritzsche, G. Asmussen, E.A. Minin, V.E. Samoilova, F.-U. Mu¨ller, W. Schmitz, M. Hasselblatt, W. Paulus, U. Muller-Werdan, J. Slezak, G. Koehler, W. Boecker, I.B. Buchwalow - Germany
Summary
Nitric oxide (NO) mediates fundamental physiological actions on skeletal muscle. The loss of NO synthase (NOS) from the sarcolemma was assumed to be associated with development of Duchenne muscular dystrophy (DMD). We have, however, recently reported that, in contrast to the commonly accepted view, NOS expression in DMD myofibres is up-regulated. This poses the question of the fibre type-specific NOS expression in DMD muscles and how the NOS expression is related to the regeneration or degeneration status. To address this issue, we examined localization of NOS isoforms I, II and III in skeletal muscles of DMD patients employing immunohistochemical labelling with tyramide signal amplification complemented with enzyme histochemistry. We found that NOS immunolabelling as well as metabolic enzyme activity in DMD muscles were heterogeneously distributed along the fibre length of DMD muscle fibres revealing regenerating and degenerate (hypercontracted) fibres as well as normal segments. Like in normal muscles, positive NOS immunoreactivity was found to be associated with fast-oxidative glycolytic (FOG) phenotype. The regeneration status of NOS-positive segments was deduced from the presence of neonatal and developmental myosin heavy chains. High NOS expression in regenerating DMD muscle fibres can be well reconciled with reports about the protective role of endogenous NO in inflammatory diseases and in muscle repair.
16 - Red-green color vision impairment in duchenne muscular dystrophy
15 -
