Lactiplantibacillus plantarum LM1001 Supplementation Attenuates Muscle Atrophy and Function Decline in Aged Mice

Background/Objectives: Aging and metabolic disorders are associated with a decline in muscle function, referred to as age-related sarcopenia. The underlying mechanisms of sarcopenia include cellular senescence, imbalanced protein homeostasis, accumulation of oxidative and inflammatory stressors, and mitochondrial dysfunction. Probiotic supplementation improves the gut microbiome and enhances muscle function via the gut–muscle axis. However, details of molecular mechanisms and the development of an appropriate treatment are under active investigation. Methods: We have examined the effects of Lactiplantibacillus plantarum LM1001, a probiotic that reportedly improves the digestibility of branched-chain amino acids in myocyte cultures, but exactly how it contributes to muscle structure and function remains unclear. Results: We show that aged mice (male C57BL6/J) fed a high-fat diet (HFD) exhibit weak muscle strength, as reflected by a reduction in grip strength. LM1001 supplementation increases muscle strength and restores myofibril size, which has been altered by HFD in aged mice. Expression of myogenic proteins is increased, while protein markers for muscle atrophy are downregulated by LM1001 treatment via the IGF-1/Akt/FoxO3a pathway. LM1001 improves gut microbiota that are altered in aged HFD-fed mice, by increasing their abundance in beneficial bacteria, and efficiently maintains the epithelial lining integrity of the large intestine. Conclusions: We conclude that LM1001 supplementation serves a beneficial role in patients suffering from sarcopenia and metabolic disorders, improving their muscle function, gut microbiota, and intestinal integrity.