Comparison of Experimental Protocols of Physical Exercise for mdx Mice and Duchenne Muscular Dystrophy Patients

Duchenne muscular dystrophy (DMD), caused by a lack of functional dystrophin, is characterized by progressive muscle degeneration. Interestingly, dystrophin is also expressed in endothelial cells (ECs), and insufficient angiogenesis has already been hypothesized to contribute to DMD pathology, however, its status in mdx mice, a model of DMD, is still not fully clear. Our study aimed to reveal angiogenesis-related alterations in skeletal muscles of mdx mice compared to wild-type (WT) counterparts. By investigating 6- and 12-week-old mice, we sought to verify if those changes are age-dependent. We utilized a broad spectrum of methods ranging from gene expression analysis, flow cytometry, and immunofluorescence imaging to determine the level of angiogenic markers and to assess muscle blood vessel abundance. Finally, we implemented the hindlimb ischemia (HLI) model, more biologically relevant in the context of functional studies evaluating angiogenesis/arteriogenesis processes. We demonstrated that both 6- and 12-week-old dystrophic mice exhibited dysregulation of several angiogenic factors, including decreased vascular endothelial growth factor A (VEGF) in different muscle types. Nonetheless, in younger, 6-week-old mdx animals, neither the abundance of CD31+α-SMA+ double-positive blood vessels nor basal blood flow and its restoration after HLI was affected. In 12-week-old mdx mice, although a higher number of CD31+α-SMA+ double-positive blood vessels and an increased percentage of skeletal muscle ECs were found, the abundance of pericytes was diminished, and blood flow was reduced. Moreover, impeded perfusion recovery after HLI associated with a blunted inflammatory and regenerative response was evident in 12-week-old dystrophic mice. Hence, our results reinforce the hypothesis of age-dependent angiogenic dysfunction in dystrophic mice. In conclusion, we suggest that older mdx mice constitute an appropriate model for preclinical studies evaluating the effectiveness of vascular-based therapies aimed at the restoration of functional angiogenesis to mitigate DMD severity.

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Have Duchenne Muscular Dystrophy Patients an Increased Cancer Risk?

Journal of Neuromuscular Diseases ◽

10.3233/jnd-210676 ◽

2021 ◽

pp. 1-5

Author(s):

Gian Luca Vita ◽

Luisa Politano ◽

Angela Berardinelli ◽

Giuseppe Vita

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Systematic Investigation ◽

Mdx Mice ◽

True Incidence ◽

Patients With Cancer ◽

Dmd Gene ◽

Age Range ◽

Prevalence Of Cancer

Background: Increasing evidence suggests that Duchenne muscular dystrophy (DMD) gene is involved in the occurrence of different types of cancer. Moreover, development of sarcomas was reported in mdx mice, the murine model of DMD, in older age. So far, nine isolated DMD patients were reported with concomitant cancer, four of whom with rhabdomyosarcoma (RMS), but no systematic investigation was performed about the true incidence of cancer in DMD. Methods: All members of the Italian Association of Myology were asked about the occurrence of cancer in their DMD patients in the last 30 years. Results: Four DMD patients with cancer were reported after checking 2455 medical records. One developed brain tumour at the age of 35 years. Two patients had alveolar RMS at 14 and 17 years of age. The fourth patient had a benign enchondroma when 11-year-old. Conclusion: Prevalence of cancer in general in the Italian DMD patients does not seem to be different from that in the general population with the same age range. Although the small numbers herein presented do not allow definitive conclusion, the frequent occurrence of RMS in DMD patients raises an alert for basic researchers and clinicians. The role of DMD gene in cancer merits further investigations.

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Autophagy in the heart is enhanced and independent of disease progression in mus musculus dystrophinopathy models

JRSM Cardiovascular Disease ◽

10.1177/2048004019879581 ◽

2019 ◽

Vol 8 ◽

pp. 204800401987958

Author(s):

HR Spaulding ◽

C Ballmann ◽

JC Quindry ◽

MB Hudson ◽

JT Selsby

Keyword(s):

Skeletal Muscle ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Disease Progression ◽

Gene Mutations ◽

Dystrophin Gene ◽

Mdx Mice ◽

Dystrophin Deficiency ◽

Muscle Wasting Disease ◽

Dystrophin Protein

Background Duchenne muscular dystrophy is a muscle wasting disease caused by dystrophin gene mutations resulting in dysfunctional dystrophin protein. Autophagy, a proteolytic process, is impaired in dystrophic skeletal muscle though little is known about the effect of dystrophin deficiency on autophagy in cardiac muscle. We hypothesized that with disease progression autophagy would become increasingly dysfunctional based upon indirect autophagic markers. Methods Markers of autophagy were measured by western blot in 7-week-old and 17-month-old control (C57) and dystrophic (mdx) hearts. Results Counter to our hypothesis, markers of autophagy were similar between groups. Given these surprising results, two independent experiments were conducted using 14-month-old mdx mice or 10-month-old mdx/Utrn± mice, a more severe model of Duchenne muscular dystrophy. Data from these animals suggest increased autophagosome degradation. Conclusion Together these data suggest that autophagy is not impaired in the dystrophic myocardium as it is in dystrophic skeletal muscle and that disease progression and related injury is independent of autophagic dysfunction.

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Differential Effects of Halofuginone Enantiomers on Muscle Fibrosis and Histopathology in Duchenne Muscular Dystrophy

International Journal of Molecular Sciences ◽

10.3390/ijms22137063 ◽

2021 ◽

Vol 22 (13) ◽

pp. 7063

Author(s):

Sharon Mordechay ◽

Shaun Smullen ◽

Paul Evans ◽

Olga Genin ◽

Mark Pines ◽

...

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Motor Coordination ◽

Mdx Mice ◽

Cell Viability Assay ◽

Muscle Fibrosis ◽

Antifibrotic Therapy ◽

Racemic Form ◽

Viability Assay

Progressive loss of muscle and muscle function is associated with significant fibrosis in Duchenne muscular dystrophy (DMD) patients. Halofuginone, an analog of febrifugine, prevents fibrosis in various animal models, including those of muscular dystrophies. Effects of (+)/(−)-halofuginone enantiomers on motor coordination and diaphragm histopathology in mdx mice, the mouse model for DMD, were examined. Four-week-old male mice were treated with racemic halofuginone, or its separate enantiomers, for 10 weeks. Controls were treated with saline. Racemic halofuginone-treated mice demonstrated better motor coordination and balance than controls. However, (+)-halofuginone surpassed the racemic form’s effect. No effect was observed for (−)-halofuginone, which behaved like the control. A significant reduction in collagen content and degenerative areas, and an increase in utrophin levels were observed in diaphragms of mice treated with racemic halofuginone. Again, (+)-halofuginone was more effective than the racemic form, whereas (−)-halofuginone had no effect. Both racemic and (+)-halofuginone increased diaphragm myofiber diameters, with no effect for (−)-halofuginone. No effects were observed for any of the compounds tested in an in-vitro cell viability assay. These results, demonstrating a differential effect of the halofuginone enantiomers and superiority of (+)-halofuginone, are of great importance for future use of (+)-halofuginone as a DMD antifibrotic therapy.

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Therapeutic Effect of Camostat Mesilate on Duchenne Muscular Dystrophy in mdx Mice

Biological and Pharmaceutical Bulletin ◽

10.1248/bpb.26.1025 ◽

2003 ◽

Vol 26 (7) ◽

pp. 1025-1027 ◽

Cited By ~ 6

Author(s):

Hitoshi Sawada ◽

Kazumi Nagahiro ◽

Yuhsuke Kikukawa ◽

Susumu Ban ◽

Reina Kakefuda ◽

...

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Therapeutic Effect ◽

Mdx Mice ◽

Camostat Mesilate

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Axonal sprouting in mdx mice and its relevance to cell and gene mediated therapies for Duchenne muscular dystrophy

Neuroscience Letters ◽

10.1016/s0304-3940(03)00220-9 ◽

2003 ◽

Vol 343 (1) ◽

pp. 67-69 ◽

Cited By ~ 11

Author(s):

Humberto Santo Neto ◽

Airton José Martins ◽

Elaine Minatel ◽

Maria Julia Marques

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Mdx Mice ◽

Axonal Sprouting

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Toll-like receptor 4 ablation in mdx mice reveals innate immunity as a therapeutic target in Duchenne muscular dystrophy

Human Molecular Genetics ◽

10.1093/hmg/ddu735 ◽

2014 ◽

Vol 24 (8) ◽

pp. 2147-2162 ◽

Cited By ~ 32

Author(s):

Christian Giordano ◽

Kamalika Mojumdar ◽

Feng Liang ◽

Christian Lemaire ◽

Tong Li ◽

...

Keyword(s):

Innate Immunity ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Therapeutic Target ◽

Mdx Mice ◽

Toll Like Receptor ◽

Toll Like Receptor 4

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Metabolomic Analyses Reveal Extensive Progenitor Cell Deficiencies in a Mouse Model of Duchenne Muscular Dystrophy

Metabolites ◽

10.3390/metabo8040061 ◽

2018 ◽

Vol 8 (4) ◽

pp. 61 ◽

Cited By ~ 10

Author(s):

Josiane Joseph ◽

Dong Cho ◽

Jason Doles

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Mouse Model ◽

Progenitor Cell ◽

Treatment Options ◽

Cell Types ◽

Mdx Mouse ◽

Mdx Mice ◽

Metabolic Alterations ◽

Potential Contributor

Duchenne muscular dystrophy (DMD) is a musculoskeletal disorder that causes severe morbidity and reduced lifespan. Individuals with DMD have an X-linked mutation that impairs their ability to produce functional dystrophin protein in muscle. No cure exists for this disease and the few therapies that are available do not dramatically delay disease progression. Thus, there is a need to better understand the mechanisms underlying DMD which may ultimately lead to improved treatment options. The muscular dystrophy (MDX) mouse model is frequently used to explore DMD disease traits. Though some studies of metabolism in dystrophic mice exist, few have characterized metabolic profiles of supporting cells in the diseased environment. Using nontargeted metabolomics we characterized metabolic alterations in muscle satellite cells (SCs) and serum of MDX mice. Additionally, live-cell imaging revealed MDX-derived adipose progenitor cell (APC) defects. Finally, metabolomic studies revealed a striking elevation of acylcarnitines in MDX APCs, which we show can inhibit APC proliferation. Together, these studies highlight widespread metabolic alterations in multiple progenitor cell types and serum from MDX mice and implicate dystrophy-associated metabolite imbalances in APCs as a potential contributor to adipose tissue disequilibrium in DMD.

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Talin, vinculin and DRP (utrophin) concentrations are increased at mdx myotendinous junctions following onset of necrosis

Journal of Cell Science ◽

10.1242/jcs.107.6.1477 ◽

1994 ◽

Vol 107 (6) ◽

pp. 1477-1483 ◽

Cited By ~ 1

Author(s):

D.J. Law ◽

D.L. Allen ◽

J.G. Tidball

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Cytoskeletal Proteins ◽

Mdx Mouse ◽

Mdx Mice ◽

Myotendinous Junction ◽

Glycoprotein Complex ◽

Transmembrane Glycoprotein ◽

Muscle Necrosis ◽

Myotendinous Junctions

Duchenne muscular dystrophy (DMD) and the myopathy seen in the mdx mouse both result from absence of the protein dystrophin. Structural similarities between dystrophin and other cytoskeletal proteins, its enrichment at myotendinous junctions, and its indirect association with laminin mediated by a transmembrane glycoprotein complex suggest that one of dystrophin's functions in normal muscle is to form one of the links between the actin cytoskeleton and the extracellular matrix. Unlike Duchenne muscular dystrophy patients, mdx mice suffer only transient muscle necrosis, and are able to regenerate damaged muscle tissue. The present study tests the hypothesis that mdx mice partially compensate for dystrophin's absence by upregulating one or more dystrophin-independent mechanisms of cytoskeleton-membrane association. Quantitative analysis of immunoblots of adult mdx muscle samples showed an increase of approximately 200% for vinculin and talin, cytoskeletal proteins that mediate thin filament-membrane interactions at myotendinous junctions. Blots also showed an increase (143%) in the dystrophin-related protein called utrophin, another myotendinous junction constituent, which may be able to substitute for dystrophin directly. Muscle samples from 2-week-old animals, a period immediately preceding the onset of muscle necrosis, showed no significant differences in protein concentration between mdx and controls. Quantitative analyses of confocal images of myotendinous junctions from mdx and control muscles show significantly higher concentrations of talin and vinculin at the myotendinous junctions of mdx muscle. These findings indicate that mdx mice may compensate in part for the absence of dystrophin by increased expression of other molecules that subsume dystrophin's mechanical function.

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