Irisin response to exercise training in adults and its effect on the regulation of C2C12 cell proliferation and differentiation
Irisin is now recognized as an exercise-induced hormone that is produced primarily by skeletal muscles and adipose tissue. However, its physiological characteristics in the response to acute or chronic exercise training still remains somewhat controversial. By using serum samples at different time points before and after an acute bout of exercise among trained and untrained healthy adults, this study showed that serum irisin transiently increases in response to acute exercise, which is independent of training status. This study also showed that running could keep irisin at significantly elevated levels for a longer time-period versus cycling; suggesting that irisin response to acute exercise is dependent upon exercise mode. By conducting a meta-analysis, this study provided evidence that chronic exercise training is associated with decreased irisin levels in the randomized controlled trials. This study further showed that differences in study design and failure to control for confounders in non-randomized studies might be the major sources of heterogeneity and bias underlying current inconsistent findings. Moreover, since regular exercise is demonstrated to be a key element in the management of some muscular diseases by preventing skeletal muscle atrophy and enhancing skeletal muscle mass, and given the fact that irisin is responsive to exercise and positively modulates the metabolism in skeletal muscle cells, it seems plausible that irisin might affect the development of skeletal muscle cells. By treating mouse skeletal muscle cells continuously with or without irisin at physiological and pharmacological concentrations during different stages of differentiation, this study showed that irisin promotes mouse skeletal muscle cell proliferation in a dose-dependent manner, while irisin seems to have no significant effects in regulating mouse skeletal muscle cell differentiation.
Subject HeadingsZellwachstum [GND]
Cell growth processes [MeSH]