Exercise-induced myokines: a brief review of controversial issues of this decade

Abstract

Myokines, known to mediate metabolism, inflammation, and other pathophysiological conditions, have been widely investigated, including myokines induced by exercise. However, among published literature, there is substantial inconsistency in the quantification of exercise-induced myokines. Here, we summarized and compared published data regarding the effects of exercise on commonly studied myokines including apelin, Brain-derived neurotrophic factor (BDNF), Interleukin-15 (IL-15), irisin, and Secreted protein acidic and rich in cysteine (SPARC) during the last decade and discussed possible reasons for discrepancy in these reports. Areas covered: A search on PubMed for original articles published in this decade was conducted, focusing on the impacts of exercises on myokines and metabolic and age-related disorders. Beneficial relationship between skeletal muscle plasticity and myokines due to exercise is also discussed. Expert commentary: Based on these analyses, exercise induces the secretion of a number of myokines, which has positive effects on metabolic diseases or age-related muscle atrophy (sarcopenia). However, among published reports, there is wide discrepancy in the quantification of myokines induced by exercise, which could be due to timing of sample collection, pre-analytic sample processing, analytical method, and calculation and other factors. Thus, these factors need to be considered in future studies on exercise induced myokines.

Fasting Insulin and Alanine Amino Transferase, but not FGF21, Were Independent Parameters Related with Irisin Increment after Intensive Aerobic Exercising

“…Consistently, irisin levels increased after 2 weeks of exercising in our cohort of young women. Based on this and a previous study, exercise induces the secretion of myokines, like irisin, and also FGF2 15,24 . We confirmed that irisin levels were significantly different between exercise workloads.…”

Maternal exercise via exerkine apelin enhances brown adipogenesis and prevents metabolic dysfunction in offspring mice

“…Despite these positive reports of exercise in enhancing UCP1 expression (26), PRDM16 expression (24), and mitochondrial biogenesis (25), there were also reports showing that exercise does not affect thermogenic and mitochondrial activity of BAT (27) or even down-regulated the BAT thermogenesis (28). These inconsistent reports could be due to the difference in exercise types, intensity and duration, and animal physiological conditions (29), as well as the timing of sample collection following exercise (29). Up to now, the impacts of exercise during pregnancy on fetal development have only been examined in obese mothers (13), and its effects on fetal BAT development and long-term thermogenesis of offspring born to healthy mothers are unknown.…”

Bidirectional Communication Between Brain and Muscle

“…For muscle to produce these effects it produces a variety of myokines that have a direct effect on the brain (16). Among these myokines the ones that have been shown to have effects on the central nervous system include insulin-growth factor-1, brain derived nerve growth factor, cathepsin-B, fibroblast growth factor-1 and irisin (17). Irisin has been considered a major peptide communicator (18), but recently studies have suggested that the assays that have been used are very nonspecific (19,20).…”