Role of adipokines in sarcopenia

Sarcopenia is an age-related disease that mainly involves decreases in muscle mass,muscle strength and muscle function.At the same time,the body fat content increases with aging,especially the visceral fat content.Adipose tissue is an endocrine organ that secretes biologically active factors called adipokines,which act on local and distant tissues.Studies have revealed that some adipokines exert regulatory effects on muscle,such as higher serum leptin levels causing a decrease in muscle function and adiponectin inhibits the transcriptional activity of Forkhead box O3(FoxO3)by activating peroxisome proliferators-activated receptor-γcoactivator-1α(PGC-1α)and sensitizing cells to insulin,thereby repressing atrophy-related genes(atrogin-1 and muscle RING finger 1[MuRF1])to prevent the loss of muscle mass.Here,we describe the effects on muscle of adipokines produced by adipose tissue,such as leptin,adiponectin,resistin,mucin and lipocalin-2,and discuss the importance of these adipokines for understanding the development of sarcopenia.