Myokines and adipokines: Involvement in the crosstalk between skeletal muscle and adipose tissue

- A summary of the roles and significance of myokines and adipokines.
- A summary of the cytokines that have roles in both skeletal muscle and adipose tissue.
- Summarize the effects of the cytokines on protein and energy metabolism in myocytes and/or adipocytes.

Skeletal muscle and adipose tissue are the two largest organs in the body. Skeletal muscle is an effector organ, and adipose tissue is an organ that stores energy; in addition, they are endocrine organs that secrete cytokines, namely myokines and adipokines, respectively. Myokines consist of myostatin, interleukin (IL)-8, IL-15, irisin, fibroblast growth factor 21, and myonectin; adipokines include leptin, adiponectin, resistin, chemerin, and visfatin. Furthermore, certain cytokines, such as IL-6 and tumor necrosis factor-α, are released by both skeletal muscle and adipose tissue and exhibit a bioactive effect; thus, they are called adipo-myokines. Recently, novel myokines or adipokines were identified through the secretomic technique, which has expanded our knowledge on the previously unknown functions of skeletal muscle and adipose tissue and provide a new avenue of investigation for obesity treatment or animal production. This review focuses on the roles of and crosstalk between myokines and adipokines in skeletal muscle and adipose tissue that modulate the molecular events in the metabolic homeostasis of the whole body.

86Skeletal muscle-derived factors “myokines” and adipose tissue-derived factors “adipokines” exert their effects mainly in the organs of adipose tissue and/or skeletal muscle to form the muscle-adipose axis that regulates body composition.