MSTN and sarcopenia: ↑ gastrocnemius muscle mass; ↓ markers of sarcopenia (HDAH4, MyoD, myogenin, myostatin); ↑ PGC1α; ↓ pro-inflammatory markers (COX-2, IL-6, IL-1β); ↑ anti-inflammatory cytokine IL-10; ↑ GLUT4 and insulin sensitivity in gastrocnemius explants