Insight into the Role of Gut Microbiota in Duchenne Muscular Dystrophy: An Age-Related Study in Mdx Mice

Exploratory Analysis of Gut Microbiota Profile in Duchenne Muscular Dystrophy (DMD) Patients with Intellectual Disability

This study investigates the differences in gut microbiota composition between DMD patients with (DMD +) and without (DMD -) intellectual disability (ID) and its potential role in cognitive outcomes. In this study, we assessed the gut microbiota in 50 genetically confirmed DMD patients (median age 13.1 years) using 16S rRNA gene sequencing. Cognitive assessment was performed using the Wechsler Intelligence Scales, with ID defined as an IQ < 70. Stool samples were analyzed, and statistical methods were used to assess alpha- and beta-diversity. Thirty-four percent of patients had ID. No significant differences were found in alpha-diversity or in the Firmicutes/Bacteroidetes ratio. However, beta-diversity analysis revealed significant differences between DMD + and DMD - groups, including, in DMD + , an increased abundance of Propionibacterium and Bifidobacterium, and a reduction in Bulleidia. These bacteria are involved in metabolic pathways that can influence neurological health through the gut-brain axis, particularly via the production of short-chain fatty acids. While these preliminary findings suggest a possible association between gut microbiota profile and cognitive impairment in DMD, further research is needed to explore a causal relationship and consider microbiota-targeted therapeutic strategies.

Advances in Duchenne Muscular Dystrophy: Diagnostic Techniques and Dystrophin Domain Insights

Abnormalities in X chromosomes, either numerical or structural, cause X-linked disorders, such as Duchenne muscular dystrophy (DMD). Recent molecular and cytogenetic techniques can help identify DMD gene mutations. The accurate diagnosis of Duchenne is crucial, directly impacting patient treatment management, genetics, and the establishment of effective prevention strategies. This review provides an overview of X chromosomal disorders affecting Duchenne and discusses how mutations in Dystrophin domains can impact detection accuracy. Firstly, the efficiency and use of cytogenetic and molecular techniques for the genetic diagnosis of Duchenne disease have, thus, become increasingly important. Secondly, artificial intelligence (AI) will be instrumental in developing future therapies by enabling the aggregation and synthesis of extensive and heterogeneous datasets, thereby elucidating underlying molecular mechanisms. However, despite advances in diagnostic technology, understanding the role of Dystrophin in Duchenne disease remains a challenge. Therefore, this review aims to synthesize this complex information to significantly advance the understanding of DMD and how it could affect patient care.

Influence of CTG repeats from the human DM1 locus on murine gut microbiota

Myotonic Dystrophy type 1 (DM1) is caused by a CTG repeat expansion in the 3' untranslated region of the DMPK gene. This expansion leads to the production of toxic RNA transcripts, which accumulate in the nucleus and interfere with normal RNA processing. DM1 affects a broad range of tissues and systems such as the skeletal muscle, the central nervous system, cardiac, visual, reproductive, and gastrointestinal (GI) system. GI dysfunction is a significant but poorly understood aspect of DM1. Particularly, it is unknown if there are alterations in the intestinal microbiome in DM1. Here, we used a transgenic humanized mouse model (DMSXL) to explore how the gut microbiome may be linked to GI issues in DM1. For this purpose, 68 stool samples from Homozygous, Heterozygous, and Wild-Type (WT) mice were collected. These samples were sequenced by MiSeq and analyzed with DADA2 to generate taxonomic profiles. Our analysis indicated that the overexpression of CTG repeats significantly influences the bacterial structure of the gut microbiome in Homozygous mice samples, especially in terms of the relative abundance of the Patescibacteria and Defferibacterota Phyla. These results provide valuable information about the gut microbiota structure thus improving the understanding of the role of these changes in the pathogenicity as well as GI problems of DM1 patients.

Serum metabolomic signatures of patients with rare neurogenetic diseases: an insight into potential biomarkers and treatment targets

Introduction

To further advance our understanding of Muscular Dystrophies (MDs) and Spinocerebellar Ataxias (SCAs), it is necessary to identify the biological patterns associated with disease pathology. Although progress has been made in the fields of genetics and transcriptomics, there is a need for proteomics and metabolomics studies. The present study aimed to be the first to document serum metabolic signatures of MDs (DMD, BMD, and LGMD 2A) SCAs (SCA 1-3), from a South Asian perspective.

Methods

A total of 28 patients (SCA 1-10, SCA 2-2, SCA 3-2, DMD-10, BMD-2, LGMD-2) and eight controls (aged 8-65 years) were included. Metabolomic analysis was performed by Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy (UPLC-MS/MS), with support from the Houston Omics Collaborative.

Results and discussion

Amino acid metabolism was the primary altered super pathway in DMD followed by carbohydrate metabolism and lipid metabolism. In contrast, BMD and LGMD 2A exhibited a more prominent alteration in lipid metabolism followed by amino acid metabolism. In SCAs, primarily lipid, amino acid, peptide, nucleotide, and xenobiotics pathways are affected. Our findings offer new insights into the variance of metabolite levels in MD and SCA, with substantial implications for pathology, drug development, therapeutic targets and clinical management. Intriguingly, this study identified two novel metabolites associated with SCA. This pilot cross-sectional study warrants further research involving larger groups of participants, to validate our findings.

The Gut Microbiota Involvement in the Panorama of Muscular Dystrophy Pathogenesis

Muscular dystrophies (MDs) are genetically heterogeneous diseases characterized by primary skeletal muscle atrophy. The collapse of muscle structure and irreversible degeneration of tissues promote the occurrence of comorbidities, including cardiomyopathy and respiratory failure. Mitochondrial dysfunction leads to inflammation, fibrosis, and adipogenic cellular infiltrates that exacerbate the symptomatology of MD patients. Gastrointestinal disorders and metabolic anomalies are common in MD patients and may be determined by the interaction between the intestine and its microbiota. Therefore, the gut-muscle axis is one of the actors involved in the spread of inflammatory signals to all muscles. In this review, we aim to examine in depth how intestinal dysbiosis can modulate the metabolic state, the immune response, and mitochondrial biogenesis in the course and progression of the most investigated MDs such as Duchenne Muscular Dystrophy (DMD) and Myotonic Dystrophy (MD1), to better identify gut microbiota metabolites working as therapeutic adjuvants to improve symptoms of MD.

Caveolin and NOS in the Development of Muscular Dystrophy

Caveolin is a structural protein within caveolae that may be involved in transmembrane molecular transport and/or various intercellular interactions within cells. Specific mutations of caveolin-3 in muscle fibers are well known to cause limb-girdle muscular dystrophy. Altered expression of caveolin-3 has also been detected in Duchenne muscular dystrophy, which may be a part of the pathological process leading to muscle weakness. Interestingly, it has been shown that the renovation of nitric oxide synthase (NOS) in sarcolemma with muscular dystrophy could improve muscle health, suggesting that NOS may be involved in the pathology of muscular dystrophy. Here, we summarize the notable function of caveolin and/or NOS in skeletal muscle fibers and discuss their involvement in the pathology as well as possible tactics for the innovative treatment of muscular dystrophies.

Motor dysfunction of the gut in Duchenne muscular dystrophy: A review

BACKGROUND

Duchenne's muscular dystrophy (DMD) is a severe type of hereditary, neuromuscular disorder caused by a mutation in the dystrophin gene resulting in the absence or production of truncated dystrophin protein. Conventionally, clinical descriptions of the disorder focus principally on striated muscle defects; however, DMD manifestations involving gastrointestinal (GI) smooth muscle have been reported, even if not rigorously studied.

PURPOSE

The objective of the present review is to offer a comprehensive perspective on the existing knowledge concerning GI manifestations in DMD, focusing the attention on evidence in DMD patients and mdx mice. This includes an assessment of symptomatology, etiological pathways, and potential corrective approaches. This paper could provide helpful information about DMD gastrointestinal implications that could serve as a valuable orientation for prospective research endeavors in this field. This manuscript emphasizes the effectiveness of mdx mice, a DMD animal model, in unraveling mechanistic insights and exploring the pathological alterations in the GI tract. The gastrointestinal consequences evident in patients with DMD and the mdx mice models are a significant area of focus for researchers. The exploration of this area in depth could facilitate the development of more efficient therapeutic approaches and improve the well-being of individuals impacted by the condition.

Exploring the Gut Microbiota-Muscle Axis in Duchenne Muscular Dystrophy

The gut microbiota plays a pivotal role in maintaining the dynamic balance of intestinal epithelial and immune cells, crucial for overall organ homeostasis. Dysfunctions in these intricate relationships can lead to inflammation and contribute to the pathogenesis of various diseases. Recent findings uncovered the existence of a gut-muscle axis, revealing how alterations in the gut microbiota can disrupt regulatory mechanisms in muscular and adipose tissues, triggering immune-mediated inflammation. In the context of Duchenne muscular dystrophy (DMD), alterations in intestinal permeability stand as a potential origin of molecules that could trigger muscle degeneration via various pathways. Metabolites produced by gut bacteria, or fragments of bacteria themselves, may have the ability to migrate from the gut into the bloodstream and ultimately infiltrate distant muscle tissues, exacerbating localized pathologies. These insights highlight alternative pathological pathways in DMD beyond the musculoskeletal system, paving the way for nutraceutical supplementation as a potential adjuvant therapy. Understanding the complex interplay between the gut microbiota, immune system, and muscular health offers new perspectives for therapeutic interventions beyond conventional approaches to efficiently counteract the multifaceted nature of DMD.