Unraveling the bidirectional relationship between muscle inflammation and satellite cells activity: influencing factors and insights.

Inflammation stands as a vital and innate function of the immune system, essential for maintaining physiological homeostasis. Its role in skeletal muscle regeneration is pivotal, with the activation of satellite cells (SCs) driving the repair and generation of new myofibers. However, the relationship between inflammation and SCs is intricate, influenced by various factors. Muscle injury and repair prompt significant infiltration of immune cells, particularly macrophages, into the muscle tissue. The interplay of cytokines and chemokines from diverse cell types, including immune cells, fibroadipogenic progenitors, and SCs, further shapes the inflammation-SCs dynamic. While some studies suggest heightened inflammation associates with reduced SC activity and increased fibro- or adipogenesis, others indicate an inflammatory stimulus benefits SC function. Yet, the existing literature struggles to delineate clearly between the stimulatory and inhibitory effects of inflammation on SCs and muscle regeneration. This paper comprehensively reviews studies exploring the impact of pharmacological agents, dietary interventions, genetic factors, and exercise regimes on the interplay between inflammation and SC activity.