The effect of acute exercise on the skeletal muscle energy metabolism in Multiple Sclerosis patients

Abstract

ABSTRACT Objective: To examine the phosphorylation patterns of adenosine monophosphate-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) in the skeletal muscle of MS patients versus healthy controls (HC). Methods: Twenty-six MS patients and 15 HC were selected for baseline comparison of skeletal muscle AMPK and mTOR phosphorylation patterns, muscle fiber cross-sectional area (CSA), fiber distribution, VO2peak and muscle strength (part one). Nine MS patients and seven HC executed an endurance exercise bout (part two). Muscle samples were taken before and after exercise to examine skeletal muscle AMPK and mTOR phosphorylation patterns. Exercise caloric expenditure, intensity and Borg-RPE were comparable between groups. Results: In part one, MS subjects had a greater skeletal muscle AMPK concentration at rest (p = 0,000), compared to the HC. Skeletal muscle AMPK phosphorylation was independently related to MS (r = 0.87, p < 0.001), this relation was absent for skeletal muscle mTOR phosphorylation (r = 0.42, p = 0.72). In part two, skeletal muscle AMPK concentrations at rest (p = 0,008) and after intervention (p = 0,005) were significantly different. Unlike the skeletal muscle mTOR concentrations at rest, those after intervention were significant (p < 0.05). In MS the relative change in skeletal muscle mTOR phosphorylation after intervention correlated significantly with VO2peak (r = -0.67, p < 0.01) and lean tissue mass (r = -0.73, p < 0.01). There was a significant correlation between the relative c