Metabolic Myopathy clinical trials

Metabolomic Approach During Exercise Testing in Myalgia Induced by eXercise

Metabolic myopathies form a group of pathologies related to a deficit of muscle energy production (enzymatic deficit) by disorder of the metabolism of carbohydrates, lipids, purines, or mitochondrial involvement related to dysfunction of complex respiratory chain. Most often, the symptomatology may include signs of "muscular" calling with cramps, contractures or exercise myalgia, more or less associated with exercise intolerance with early fatigability and rhabdomyolysis. In practice, the clinical signs are not specific and not pathognomonic, or sometimes absent with only an isolated elevation of the CPK. The diagnosis of certainty is usually based on the realization of a muscle biopsy (invasive). Unfortunately, the performance of the biopsy (definitive diagnosis of myopathy) in front of myalgia is low, hence the interest of functional explorations upstream to better specify its indication. Given the considerable increase in muscle metabolism to physical effort, resting investigations may not uncover myo-metabolic deficit. The muscle enzymatic deficit, is therefore most often "silent" at rest and its highlighting requires to explore the patient with effort, asking him to perform an exercise test on cycloergometer and/or an isometric contraction of the forearm ('handgrip test'). Currently, only a few metabolites are dosed before and after exertion such as lactate, pyruvic acid and ammonium. Several studies in normal subjects showed the effect of physical exercise on the metabolomic signature of plasma. Our aim is to apply modern metabolomic techniques to plasma and urinary samples collected as part of the care pathway in patients referred to in the Department of Sports Medicine-Functional Explorations of the CHU in comparison with healthy volunteers).