Exercise Capacity of Patients With Dermatomyosis

Study Overview
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Brief Summary
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Dermatomyositis (DM) patients experience muscle weakness and low aerobic capacities, which are associated with poor health status and increased mortality. The origin of this muscle impairment remains unknown. The investigators hypothesize that mitochondria functioning is impaired in DM muscle and links with exercise capacities.

Official Title
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Exercise Capacity of Patients With Dermatomyosisthe Role of Muscle Mitochondria and Reactive Oxygen Species

Conditions
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Dermatomyositis

Intervention / Treatment
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* Other: exploration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Woman or man> 18 years, Signature of informed consent, Muscle biopsy for suspicion of recent inflammatory myopathy (<6 months) or for exclusion of neuromuscular pathology. Prospectively, following the results of the muscle biopsy, the subjects will divided into three groups meeting the following criteria: DM group: DM according to the ENMC criteria; other inflammatory myopathy group: polymyositis, autoimmune necrotizing myopathy, non-specific myositis or inclusion myositis according to the ENMC criteria; Group no neuromuscular pathology: i) myalgia and / or intolerance to exercise and ii) normal neuromuscular examination, iii) no increase in blood creatine kinase level, iv) absence of electromyographic abnormality, v) histological Muscle mass. Exclusion Criteria: - Taking an immunomodulatory treatment within 6 months before inclusion, Paraneoplastic form of the disease, Presence of associated interstitial pneumonitis, Neuromuscular pathology different from inflammatory myopathy, Unbalanced cardiovascular disease, Impossibility of giving the subject informed information (subject in an emergency situation, difficulty in understanding the subject, ...), Subject under safeguard of justice, Subject under tutelage or under curators, Pregnancy (positive pregnancy test) Breastfeeding.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dermatomyositis (DM)<br>Patients with dermatomyositis according to ENMC criteria | Other: exploration<br>* Difference of the following parameters in patients i) with DM, ii) with another inflammatory myopathy iii) without neuromuscular disease.<br>|
| Active Comparator: Non-dermatomyositis inflammatory myopathies<br>Patients with other inflammatory myopathy than dermatomyositis according to ENMC criteria | Other: exploration<br>* Difference of the following parameters in patients i) with DM, ii) with another inflammatory myopathy iii) without neuromuscular disease.<br>|
| No Intervention: No myopathy<br>Patients without myopathy on muscle biopsy | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in the capacity of muscle fibers to consume oxygen in the muscle of patients i) with DM, ii) with other inflammatory myopathy, iii) without neuromuscular disease. | This difference in mitochondrial breathing capacity in the muscle will be achieved by: Muscle biopsy | Baseline |