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Frontiers in Physiology 2023Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy. The... (Review)
Review
Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy. The identification of the dystrophin gene as central to DMD pathogenesis has led to the understanding of the muscle membrane and the proteins involved in membrane stability as the focal point of the disease. The lessons learned from decades of research in human genetics, biochemistry, and physiology have culminated in establishing the myriad functionalities of dystrophin in striated muscle biology. Here, we review the pathophysiological basis of DMD and discuss recent progress toward the development of therapeutic strategies for DMD that are currently close to or are in human clinical trials. The first section of the review focuses on DMD and the mechanisms contributing to membrane instability, inflammation, and fibrosis. The second section discusses therapeutic strategies currently used to treat DMD. This includes a focus on outlining the strengths and limitations of approaches directed at correcting the genetic defect through dystrophin gene replacement, modification, repair, and/or a range of dystrophin-independent approaches. The final section highlights the different therapeutic strategies for DMD currently in clinical trials.
PubMed: 37435300
DOI: 10.3389/fphys.2023.1183101 -
Current Opinion in Neurology Oct 2023The purpose of this review is to summarise the recent developments in trial readiness, natural history studies, and interventional clinical trials for Becker muscular... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to summarise the recent developments in trial readiness, natural history studies, and interventional clinical trials for Becker muscular dystrophy (BMD).
RECENT FINDINGS
As several treatment concepts have claimed to convert patients with Duchenne muscular dystrophy (DMD) into a BMD phenotype, BMD itself has moved into the focus of clinical research. Natural history studies have helped to better characterize patients with BMD and the disease is now a target for interventional trials. In parallel, there have been advances in diagnostics and in the development of preclinical models.
SUMMARY
Despite increased collaborative efforts to improve trial readiness amongst patients with BMD, there is still a lack of long-term natural history data, and the broad spectrum of disease severity remains a challenge for well designed clinical trials.
Topics: Humans; Muscular Dystrophy, Duchenne; Phenotype; Research Design
PubMed: 37591308
DOI: 10.1097/WCO.0000000000001191 -
Journal of Neurology Oct 2023Becker muscular dystrophy (BMD) is one of the most frequent among neuromuscular diseases, affecting approximately 1 in 18,000 male births. It is linked to a genetic... (Review)
Review
Becker muscular dystrophy (BMD) is one of the most frequent among neuromuscular diseases, affecting approximately 1 in 18,000 male births. It is linked to a genetic mutation on the X chromosome. In contrast to Duchenne muscular dystrophy, for which improved care and management have changed the prognosis and life expectancy of patients, few guidelines have been published for management of BMD. Many clinicians are inexperienced in managing the complications of this disease. In France, a committee of experts from a wide range of disciplines met in 2019 to establish recommendations, with the goal of improving care of patients with BMD. Here, we present the tools to provide diagnosis of BMD as quickly as possible and for differential diagnoses. Then, we describe the multidisciplinary approach essential for optimum management of BMD. We give recommendations for the initial assessment and follow-up of the neurological, respiratory, cardiac, and orthopedic consequences of males who present with BMD. Finally, we describe the optimal therapeutic management of these complications. We also provide guidance on cardiac management for female carriers.
Topics: Humans; Male; Female; Muscular Dystrophy, Duchenne; Heterozygote; Prognosis; Diagnosis, Differential; Mutation
PubMed: 37422773
DOI: 10.1007/s00415-023-11837-5 -
Biomolecules Aug 2023Dystrophinopathies are x-linked muscular disorders which emerge from mutations in the gene, including Duchenne and Becker muscular dystrophy, and dilated... (Review)
Review
Dystrophinopathies are x-linked muscular disorders which emerge from mutations in the gene, including Duchenne and Becker muscular dystrophy, and dilated cardiomyopathy. However, Duchenne muscular dystrophy interconnects with bone loss and osteoporosis, which are exacerbated by glucocorticoids therapy. Procedures for diagnosing dystrophinopathies include creatine kinase assay, haplotype analysis, Southern blot analysis, immunological analysis, multiplex PCR, multiplex ligation-dependent probe amplification, Sanger DNA sequencing, and next generation DNA sequencing. Pharmacological therapy for dystrophinopathies comprises glucocorticoids (prednisone, prednisolone, and deflazacort), vamorolone, and ataluren. However, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and β-blockers are the first-line to prevent dilated cardiomyopathy in dystrophinopathy patients. Duchenne muscular dystrophy gene therapy strategies involve gene transfer, exon skipping, exon reframing, and CRISPR gene editing. Eteplirsen, an antisense-oligonucleotide drug for skipping exon 51 from the gene, is available on the market, which may help up to 14% of Duchenne muscular dystrophy patients. There are various FDA-approved exon skipping drugs including ExonDys-51 for exon 51, VyonDys-53 and Viltolarsen for exon 53 and AmonDys-45 for exon 45 skipping. Other antisense oligonucleotide drugs in the pipeline include casimersen for exon 45, suvodirsen for exon 51, and golodirsen for exon 53 skipping. Advances in the diagnosis and therapy of dystrophinopathies offer new perspectives for their early discovery and care.
Topics: Humans; Dystrophin; Muscular Dystrophy, Duchenne; Cardiomyopathy, Dilated; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Oligonucleotides, Antisense
PubMed: 37759719
DOI: 10.3390/biom13091319 -
Nature Communications Aug 2023Duchenne muscular dystrophy is caused by mutations in the DMD gene, leading to lack of dystrophin. Chronic muscle damage eventually leads to histological alterations in...
Duchenne muscular dystrophy is caused by mutations in the DMD gene, leading to lack of dystrophin. Chronic muscle damage eventually leads to histological alterations in skeletal muscles. The identification of genes and cell types driving tissue remodeling is a key step to developing effective therapies. Here we use spatial transcriptomics in two Duchenne muscular dystrophy mouse models differing in disease severity to identify gene expression signatures underlying skeletal muscle pathology and to directly link gene expression to muscle histology. We perform deconvolution analysis to identify cell types contributing to histological alterations. We show increased expression of specific genes in areas of muscle regeneration (Myl4, Sparc, Hspg2), fibrosis (Vim, Fn1, Thbs4) and calcification (Bgn, Ctsk, Spp1). These findings are confirmed by smFISH. Finally, we use differentiation dynamic analysis in the D2-mdx muscle to identify muscle fibers in the present state that are predicted to become affected in the future state.
Topics: Animals; Mice; Muscular Dystrophy, Duchenne; Transcriptome; Mice, Inbred mdx; Muscle, Skeletal; Dystrophin; Disease Models, Animal
PubMed: 37582915
DOI: 10.1038/s41467-023-40555-9 -
Journal of Clinical Medicine Jul 2023Limb-girdle muscular dystrophies (LGMDs) are caused by mutations in multiple genes. This review article presents 39 genes associated with LGMDs. Some forms are inherited... (Review)
Review
Limb-girdle muscular dystrophies (LGMDs) are caused by mutations in multiple genes. This review article presents 39 genes associated with LGMDs. Some forms are inherited in a dominant fashion, while for others this occurs recessively. The classification of LGMDs has evolved through time. Lately, to be considered an LGMD, the mutation has to cause a predominant proximal muscle weakness and must be found in two or more unrelated families. This article also presents therapies for LGMDs, examining both available treatments and those in development. For now, only symptomatic treatments are available for patients. The goal is now to solve the problem at the root of LGMDs instead of treating each symptom individually. In the last decade, multiple other potential treatments were developed and studied, such as stem-cell transplantation, exon skipping, gene delivery, RNAi, and gene editing.
PubMed: 37510884
DOI: 10.3390/jcm12144769 -
Journal of Neurology Aug 2023Strategic Targeting of Registries and International Database of Excellence (STRIDE) is an ongoing, international, multicenter registry of real-world ataluren use in...
Safety and effectiveness of ataluren in patients with nonsense mutation DMD in the STRIDE Registry compared with the CINRG Duchenne Natural History Study (2015-2022): 2022 interim analysis.
OBJECTIVE
Strategic Targeting of Registries and International Database of Excellence (STRIDE) is an ongoing, international, multicenter registry of real-world ataluren use in individuals with nonsense mutation Duchenne muscular dystrophy (nmDMD) in clinical practice. This updated interim report (data cut-off: January 31, 2022), describes STRIDE patient characteristics and ataluren safety data, as well as the effectiveness of ataluren plus standard of care (SoC) in STRIDE versus SoC alone in the Cooperative International Neuromuscular Research Group (CINRG) Duchenne Natural History Study (DNHS).
METHODS
Patients are followed up from enrollment for at least 5 years or until study withdrawal. Propensity score matching was performed to identify STRIDE and CINRG DNHS patients who were comparable in established predictors of disease progression.
RESULTS
As of January 31, 2022, 307 patients were enrolled from 14 countries. Mean (standard deviation [SD]) ages at first symptoms and at genetic diagnosis were 2.9 (1.7) years and 4.5 (3.7) years, respectively. Mean (SD) duration of ataluren exposure was 1671 (56.8) days. Ataluren had a favorable safety profile; most treatment-emergent adverse events were mild or moderate and unrelated to ataluren. Kaplan-Meier analyses demonstrated that ataluren plus SoC significantly delayed age at loss of ambulation by 4 years (p < 0.0001) and age at decline to %-predicted forced vital capacity of < 60% and < 50% by 1.8 years (p = 0.0021) and 2.3 years (p = 0.0207), respectively, compared with SoC alone.
CONCLUSION
Long-term, real-world treatment with ataluren plus SoC delays several disease progression milestones in individuals with nmDMD. NCT02369731; registration date: February 24, 2015.
Topics: Humans; Codon, Nonsense; Muscular Dystrophy, Duchenne; Registries; Disease Progression
PubMed: 37115359
DOI: 10.1007/s00415-023-11687-1 -
Therapeutic Advances in Neurological... 2023Duchenne muscular dystrophy (DMD) is a devastating disease that results in life-limiting complications such as loss of skeletal muscle function as well as respiratory... (Review)
Review
Duchenne muscular dystrophy (DMD) is a devastating disease that results in life-limiting complications such as loss of skeletal muscle function as well as respiratory and cardiac complications. Advanced therapeutics in pulmonary care have significantly reduced respiratory complication-related mortality, making cardiomyopathy the main determinant factor of survival. While there are multiple therapies such as the use of anti-inflammatory drugs, physical therapy, and ventilatory assistance targeted toward delaying the disease progression in DMD, a cure remains elusive. In the last decade, several therapeutic approaches have been developed to improve patient survival. These include small molecule-based therapy, micro-dystrophin gene delivery, CRISPR-mediated gene editing, nonsense readthrough, exon skipping, and cardiosphere-derived cell therapy. Associated with the specific benefits of each of these approaches are their individual risks and limitations. The variability in the genetic aberrations leading to DMD also limits the widespread use of these therapies. While numerous approaches have been explored to treat DMD pathophysiology, only a handful have successfully advanced through the preclinical stages. In this review, we summarize the currently approved as well as the most promising therapeutics undergoing clinical trials aimed toward treating DMD with a focus on its cardiac manifestations.
PubMed: 37425427
DOI: 10.1177/17562864231182934