Overview of sarcopenia pathophysiology. Abbreviations: Akt, protein kinase B; Bnip3, Bcl-2 interacting protein 3; Drp1, dynamin-related protein 1; Fis1, fission 1 homolog protein; FoxO, forkhead box O; IGF-1, insulin-like growth factor-1; LC3, light chain 3; Mfn, mitofusin; mTOR, mammalian target of rapamycin; MuRF1, muscle RING-finger protein-1; NF-κB, nuclear factor kappa B; Opa1; optic atrophy-1; PI3K, phosphatidylinositol 3-kinase; Pgc-1α, proliferator-activated receptor γ coactivator-1 alpha; p70S6K, ribosomal protein S6 kinase; ROS, reactive oxygen species; SC, satellite cell; SASP, senescence-associated secretory phenotype; UPS, ubiquitin-proteasome system; 4E-BP1, 4E-binding protein 1.