N-acetyl cysteine alleviates oxidative stress and protects mice from dilated cardiomyopathy caused by mutations in nuclear A-type lamins gene

Cardiomyopathy caused by lamin A/C gene (LMNA) mutations (hereafter referred as LMNA cardiomyopathy) is an anatomic and pathologic condition associated with muscular and electrical dysfunction of the heart, often leading to heart failure-related disability. There is currently no specific therapy available for patients that target the molecular pathophysiology of LMNA cardiomyopathy. We showed here an increase in oxidative stress levels in the hearts of mice carrying LMNA mutation, associated with a decrease of the key cellular antioxidant glutathione (GHS). Oral administration of N-acetyl cysteine, a GHS precursor, led to a marked improvement of GHS content, a decrease in oxidative stress markers including protein carbonyls and an improvement of left ventricular structure and function in a model of LMNA cardiomyopathy. Collectively, our novel results provide therapeutic insights into LMNA cardiomyopathy

International workshop on assessment of upper limb function in Duchenne Muscular Dystrophy: Rome, 15-16 February 2012

Twenty clinicians, physiotherapists and representatives from advocacy groups and industries from six countries convened for a Parent Project sponsored workshop on \u2018Assessment of Upper Limb Function in Duchenne Muscular Dystrophy (DMD)\u2019. Following previous meetings [1,2] highlighting the lack of outcome measures in non ambulant patients, a number of exploratory studies have been planned to investigate the suitability of the avai

Molecular, Physiological, and Motor Performance Defects in DMSXL Mice Carrying > 1,000 CTG Repeats from the Human DM1 Locus

International audienceMyotonic dystrophy type 1 (DM1) is caused by an unstable CTG repeat expansion in the 39UTR of the DM protein kinase (DMPK) gene. DMPK transcripts carrying CUG expansions form nuclear foci and affect splicing regulation of various RNA transcripts. Furthermore, bidirectional transcription over the DMPK gene and non-conventional RNA translation of repeated transcripts have been described in DM1. It is clear now that this disease may involve multiple pathogenic pathways including changes in gene expression, RNA stability and splicing regulation, protein translation, and micro-RNA metabolism. We previously generated transgenic mice with 45-kb of the DM1 locus and >300 CTG repeats (DM300 mice). After successive breeding and a high level of CTG repeat instability, we obtained transgenic mice carrying >1,000 CTG (DMSXL mice). Here we described for the first time the expression pattern of the DMPK sense transcripts in DMSXL and human tissues. Interestingly, we also demonstrate that DMPK antisense transcripts are expressed in various DMSXL and human tissues, and that both sense and antisense transcripts accumulate in independent nuclear foci that do not co-localize together. Molecular features of DM1-associated RNA toxicity in DMSXL mice (such as foci accumulation and mild missplicing), were associated with high mortality, growth retardation, and muscle defects (abnormal histopathology, reduced muscle strength, and lower motor performances). We have found that lower levels of IGFBP-3 may contribute to DMSXL growth retardation, while increased proteasome activity may affect muscle function. These data demonstrate that the human DM1 locus carrying very large expansions induced a variety of molecular and physiological defects in transgenic mice, reflecting DM1 to a certain extent. As a result, DMSXL mice provide an animal tool to decipher various aspects of the disease mechanisms. In addition, these mice can be used to test the preclinical impact of systemic therapeutic strategies on molecular and physiological phenotypes

Longitudinal functional and NMR assessment of upper limbs in Duchenne muscular dystrophy

International audienceObjective:To explore the value of nuclear magnetic resonance (NMR) and functional assessments for follow-up of ambulatory and nonambulatory patients with Duchenne muscular dystrophy (DMD).Methods:Twenty-five 53-skippable patients with DMD were included in this study; 15 were nonambulatory at baseline. All patients underwent clinical and functional assessments every 6 months using the Motor Function Measure (MFM), hand grip and key pinch strength, MoviPlate, and NMR spectroscopy and imaging studies.Results:Upper limb distal strength decreased in nonambulatory patients over the period of 1 year; ambulatory patients showed improvement during the same period. The same applied for several NMRS indices, such as phosphocreatine/adenosine triphosphate, which decreased in older patients but increased in younger ambulatory patients. Fat infiltration in the upper limbs increased linearly with age. Almost all NMR and functional assessment results correlated.Conclusions:Our results underscore complementarity of functional and NMR assessments in patients with DMD. Sensitivity to change of various indices may differ according to disease stage

Assessment of disease progression in dysferlinopathy. A 1-year cohort study

Jain COS Consortium.[Objective] To assess the ability of functional measures to detect disease progression in dysferlinopathy over 6 months and 1 year.[Methods] One hundred ninety-three patients with dysferlinopathy were recruited to the Jain Foundation's International Clinical Outcome Study for Dysferlinopathy. Baseline, 6-month, and 1-year assessments included adapted North Star Ambulatory Assessment (a-NSAA), Motor Function Measure (MFM-20), timed function tests, 6-minute walk test (6MWT), Brooke scale, Jebsen test, manual muscle testing, and hand-held dynamometry. Patients also completed the ACTIVLIM questionnaire. Change in each measure over 6 months and 1 year was calculated and compared between disease severity (ambulant [mild, moderate, or severe based on a-NSAA score] or nonambulant [unable to complete a 10-meter walk]) and clinical diagnosis.[Results] The functional a-NSAA test was the most sensitive to deterioration for ambulant patients overall. The a-NSAA score was the most sensitive test in the mild and moderate groups, while the 6MWT was most sensitive in the severe group. The 10-meter walk test was the only test showing significant change across all ambulant severity groups. In nonambulant patients, the MFM domain 3, wrist flexion strength, and pinch grip were most sensitive. Progression rates did not differ by clinical diagnosis. Power calculations determined that 46 moderately affected patients are required to determine clinical effectiveness for a hypothetical 1-year clinical trial based on the a-NSAA as a clinical endpoint.[Conclusion] Certain functional outcome measures can detect changes over 6 months and 1 year in dysferlinopathy and potentially be useful in monitoring progression in clinical trials.[ClinicalTrials.gov identifier] NCT01676077.The estimated US $4 million needed to fund this study is being provided by the Jain Foundation. The John Walton Centre Muscular Dystrophy Research Centre is part of the MRC Centre for Neuromuscular Diseases (grant MR/K000608/1)