scholarly journals SR Ca2+ handling in unbranched, immediately post-necrotic fast-twitch mdx fibres is similar to wt littermates

2021 ◽  
Author(s):  
Stephen Chan ◽  
Sindy L.L. Kueh ◽  
John W Morley ◽  
Stewart Head
Keyword(s):  
Animal Model ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Rise Time ◽  
Mdx Mice ◽  
Regenerative Processes ◽  
Dystrophin Deficiency ◽  
Massive Necrosis ◽  
Early Effects ◽  
Fast Twitch

There is a lack of consensus in the literature regarding the effects of dystrophin deficiency on the Ca2+ handling properties of the sarcoplasmic reticulum (SR) in mdx mice, an animal model of Duchenne muscular dystrophy. One possible reason for this is that only a few studies control for the presence of branched fibres. Fibre branching, a consequence of degenerative-regenerative processes such as muscular dystrophy, has in itself a significant influence on the function of the SR. In our present study we attempt to detect early effects of dystrophin deficiency on SR Ca2+ handling by using unbranched fibres from the immediate post-necrotic stage in mdx mice (just regenerated following massive necrosis). Using kinetically-corrected Fura-2 fluorescence signals measured during twitch and tetanus, we analysed the amplitude, rise time and decay time of Δ[Ca2+]i in unfatigued and fatigued fibres. Decay was also resolved into SR pump and SR leak components. Fibres from mdx mice were similar in all respects to fibres from wt littermates apart from: (i) a longer rise time and slower rate of rise of [Ca2+]i during a tetanus; and (ii) a mitigation of the fall in Δ[Ca2+]i amplitude during the course of fatigue. Our findings suggest that the early effects of a loss of dystrophin on SR Ca2+ handling are only slight, and differ from the widely held view that there is significant Ca2+ pathology in mdx mice. It may be that Ca2+pathology is magnified by progressive branching and degeneration.

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

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.

scholarly journals Biomarker-focused multi-drug combination therapy and repurposing trial in mdx mice

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246507
Author(s):  
Michael Ziemba ◽  
Molly Barkhouse ◽  
Kitipong Uaesoontrachoon ◽  
Mamta Giri ◽  
Yetrib Hathout ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Serum Proteins ◽  
Mdx Mice ◽  
Proteomic Profiling ◽  
Treatment Groups ◽  
Dystrophin Deficiency ◽  
Repurposed Drugs ◽  
Good Concordance ◽  
Pharmacodynamic Biomarkers

Duchenne muscular dystrophy is initiated by dystrophin deficiency, but downstream pathophysiological pathways such as membrane instability, NFĸB activation, mitochondrial dysfunction, and induction of TGFβ fibrosis pathways are thought to drive the disability. Dystrophin replacement strategies are hopeful for addressing upstream dystrophin deficiency; however, all methods to date use semi-functional dystrophin proteins that are likely to trigger downstream pathways. Thus, combination therapies that can target multiple downstream pathways are important in treating DMD, even for dystrophin-replacement strategies. We sought to define blood pharmacodynamic biomarkers of drug response in the mdx mouse model of Duchenne muscular dystrophy using a series of repurposed drugs. Four-week-old mdx mice were treated for four weeks with four different drugs singly and in combination: vehicle, prednisolone, vamorolone, rituximab, β-aminoisobutyric acid (BAIBA) (11 treatment groups; n = 6/group). Blood was collected via cardiac puncture at study termination, and proteomic profiling was carried out using SOMAscan aptamer panels (1,310 proteins assayed). Prednisolone was tested alone and in combination with other drugs. It was found to have a good concordance of prednisolone-responsive biomarkers (56 increased by prednisolone, 39 decreased) focused on NFκB and TGFβ cascades. Vamorolone shared 45 (80%) of increased biomarkers and 13 (33%) of decreased biomarkers with prednisolone. Comparison of published human corticosteroid-responsive biomarkers to our mdx data showed 14% (3/22) concordance between mouse and human. Rituximab showed fewer drug-associated biomarkers, with the most significant being human IgG. On the other hand, BAIBA treatment (high and low dose) showed a drug-associated increase in 40 serum proteins and decreased 5 serum proteins. Our results suggest that a biomarker approach could be employed for assessing drug combinations in both mouse and human studies.

scholarly journals Wheat Kernel Ingestion Protects from Progression of Muscle Weakness in mdx Mice, an Animal Model of Duchenne Muscular Dystrophy

1996 ◽  
Vol 40 (3) ◽  
pp. 444-449 ◽  
Author(s):  
Christoph Hübner ◽  
Hans-Anton Lehr ◽  
Robert Bodlaj ◽  
Barbara Finckh ◽  
Konrad Oexle ◽  
...  
Keyword(s):  
Animal Model ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Weakness ◽  
Mdx Mice ◽  
Wheat Kernel

MDX mouse myopathy I: Presence or absence of sarcolemmal lesions in tibialis anterior muscles from mice of different ages

1989 ◽  
Vol 47 ◽  
pp. 1070-1071
Author(s):  
H.D. Geissinger ◽  
L.D. Rhodes
Keyword(s):  
Animal Model ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Tibialis Anterior ◽  
Extensor Digitorum Longus ◽  
Morphological Analysis ◽  
Control Mouse ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Recent Interest

Since the ‘mdx’ mouse appears to have the same basic defect as sufferers of human Duchenne Muscular Dystrophy (DMD), much recent interest in this possible animal model for the human disease has been generated. Perforations in the sarcolemma have been reported recently in the necrotic tibialis anterior (TA) of 35-days-old and the extensor digitorum longus muscles of 39-days-old ‘mdx’ mice. It is the purpose of this communication to find out if these lesions occur not only in necrotic, but also in unaffected, or in centronucleated fibers of the TA of mice which are younger than 35, or older than 39 days.METHODS: TA from 22-, 25-, 41-, 61- and 99-days-old C57BL/10ScSn/MDX and C57BL/lOScSn control mice were pinned on corkboard in a relaxed state, prefixed for 30 minutes in 2.5% glutaraldehyde followed by routine processing for TEM. Appropriate micrographs were evaluated for a more detailed morphological analysis of the sarcolemma (SL) and the basal lamina (BL).RESULTS: It should be stated beforehand that in all muscles examined the BL appeared to be intact. In the muscles of a 25-days-old control mouse the SL appeared quite intact (FIG. 1). In contrast to this small perforations or large tears in the SL could be seen in otherwise unaffected muscles of 22- (FIG. 2), 25- and 41-days-old ‘mdx’ mice, as well as in necrotic and regenerating fibers of mice from these ages.

scholarly journals Swimming Prevents Memory Impairment by Increasing the Antioxidant Defense in an Animal Model of Duchenne Muscular Dystrophy

2019 ◽  
Author(s):  
Priscila Mantovani Nocetti Ribeiro ◽  
Adriano Alberti ◽  
Viviane Freiberger ◽  
Letícia Ventura ◽  
Leoberto Ricardo Grigollo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Animal Model ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Antioxidant Defense ◽  
Antioxidant Defenses ◽  
Mdx Mice ◽  
Encephalic Structures ◽  
And Oxidative Stress

Duchenne muscular dystrophy (DMD) is a genetic disease which is associated to a progressive skeletical muscle degeneration. Swimming is usually indicated for avoiding impact and facilitating adherence because of a better adaptation to a warm water invironment and also for its benefits on cognition, and modulating memory and learning processes and for increasing antioxidant defenses in oxidative stress. The objective of this study was to evaluate the effects of a swimming protocol on memory and oxidative stress in an animal model of Duchenne muscular dystrophy. Methods: male mdx and wild type mice within 28 days were used in this study. The animals were trained in an stepped swimming protocol for four consecutive weeks. Twenty four hours after the last exercise day, aversive memory and habituation memory tests were performed and removed the encephalic structures of striatus, pre frontal cortex, hippocampus, and cortex and gastrocnemius and diafragma muscles to evaluate protein carbonilation and lipid peroxidation and free thiols. Results: it was verified that swimming was able to reduce significantly the levels of lipid peroxidation and protein carbonilation in gastrocnemius and hippocampus and striatus in exercised animals. Swimming has also prevented lipid peroxidation in diafragma. Besides, this swimming protocol was able to increase free thiols in gastrocnemius, diafragma and in analysed SNC structures. These results showed that swimming prevented aversive and habituation memory in mdx mice.

scholarly journals Nutraceutical and pharmaceutical cocktails did not improve muscle function or reduce histological damage in D2-mdx mice

2019 ◽  
Vol 127 (4) ◽  
pp. 1058-1066
Author(s):  
Hannah R. Spaulding ◽  
Tiffany Quindry ◽  
Kayleen Hammer ◽  
John C. Quindry ◽  
Joshua T. Selsby
Keyword(s):  
Skeletal Muscle ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Function ◽  
Sirtuin 1 ◽  
Mdx Mice ◽  
Limb Muscle ◽  
Nicotinamide Riboside ◽  
Histological Damage ◽  
Dystrophin Deficiency

Progressive muscle injury and weakness are hallmarks of Duchenne muscular dystrophy. We showed previously that quercetin (Q) partially protected dystrophic limb muscles from disease-related injury. As quercetin activates PGC-1α through Sirtuin-1, an NAD+-dependent deacetylase, the depleted NAD+ in dystrophic skeletal muscle may limit quercetin efficacy; hence, supplementation with the NAD+ donor, nicotinamide riboside (NR), may facilitate quercetin efficacy. Lisinopril (Lis) protects skeletal muscle and improves cardiac function in dystrophin-deficient mice; therefore, it was included in this study to evaluate the effects of lisinopril used with quercetin and NR. Our purpose was to determine the extent to which Q, NR, and Lis decreased dystrophic injury. We hypothesized that Q, NR, or Lis alone would improve muscle function and decrease histological injury and when used in combination would have additive effects. Muscle function of 11-mo-old DBA (healthy), D2-mdx (dystrophin-deficient), and D2-mdx mice was assessed after treatment with Q, NR, and/or Lis for 7 mo. To mimic typical pharmacology of patients with Duchenne muscular dystrophy, a group was treated with prednisolone (Pred) in combination with Q, NR, and Lis. At 11 mo of age, dystrophin deficiency decreased specific tension and tetanic force in the soleus and extensor digitorum longus muscles and was not corrected by any treatment. Dystrophic muscle was more sensitive to contraction-induced injury, which was partially offset in the QNRLisPred group, whereas fatigue was similar between all groups. Treatments did not decrease histological damage. These data suggest that treatment with Q, NR, Lis, and Pred failed to adequately maintain dystrophic limb muscle function or decrease histological damage. NEW & NOTEWORTHY Despite a compelling rationale and previous evidence to the contrary in short-term investigations, quercetin, nicotinamide riboside, or Lisinopril, alone or in combination, failed to restore muscle function or decrease histological injury in dystrophic limb muscle from D2-mdx mice after long-term administration. Importantly, we also found that in the D2-mdx model, an emerging and relatively understudied model of Duchenne muscular dystrophy dystrophin deficiency caused profound muscle dysfunction and histopathology in skeletal muscle.

ELECTROMYOGRAPHIC (EMG) CHARACTERIZATION OF THE MDX MICE: AN ANIMAL MODEL FOR DUCHENNE MUSCULAR DYSTROPHY

2005 ◽  
Vol 84 (3) ◽  
pp. 202 ◽  
Author(s):  
Jay J. Han ◽  
Jennifer J. Ra ◽  
Richard T. Abresch ◽  
Lawrence R. Robinson ◽  
Jeffrey S. Chamberlain ◽  
...  
Keyword(s):  
Animal Model ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mdx Mice

scholarly journals Age-Dependent Dysregulation of Muscle Vasculature and Blood Flow Recovery after Hindlimb Ischemia in the mdx Model of Duchenne Muscular Dystrophy

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 481
Author(s):  
Paulina Podkalicka ◽  
Olga Mucha ◽  
Katarzyna Kaziród ◽  
Iwona Bronisz-Budzyńska ◽  
Sophie Ostrowska-Paton ◽  
...  
Keyword(s):  
Blood Flow ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Blood Vessels ◽  
Mdx Mice ◽  
Hindlimb Ischemia ◽  
Double Positive ◽  
Functional Studies ◽  
Age Dependent ◽  
Dystrophic Mice

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.

Have Duchenne Muscular Dystrophy Patients an Increased Cancer Risk?

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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