Postbiotic Intervention in Sarcopenia: The Role of Lactiplantibacillus plantarum HY7715 and Its Extracellular Vesicles.

Sarcopenia, the age-related loss of skeletal muscle mass and function, is associated with inflammation, mitochondrial dysfunction, and gut barrier impairment. This study investigates the postbiotic effects of heat-killed Lactiplantibacillus plantarum HY7715 (HY7715) and its extracellular vesicles (EVs) on muscle health and intestinal integrity. In C2C12 myotubes, both treatments enhanced myogenic differentiation by upregulating Myf5 and MYOG, and improved mitochondrial activity and biogenesis via increased PGC1α and mTOR expression. Under TNFα-induced muscle atrophy, they suppressed expression of atrophy-related markers (Fbox32, MuRF1, and myostatin). EVs showed stronger anti-inflammatory effects by reducing IL6 expression in muscle cells. In intestinal Caco-2 cells, HY7715-derived EVs improved barrier function by upregulating tight junction proteins (ZO-1, occludin, and claudins), and effectively reduced LPS-induced inflammation. These findings suggest that heat-killed HY7715 and its EVs may alleviate sarcopenia by enhancing muscle regeneration and maintaining intestinal homeostasis, highlighting their potential as safe, gut-muscle axis-targeting postbiotic interventions for healthy aging.