Role of IL-16 in age-related skeletal muscle atrophy: an integrated study.

[BACKGROUND] In this study, we aim to explore the roles of IL-16 in sarcopenia based on older orthopedic patients and animal research.

[METHODS] This clinical research in this study was an observational investigation and included all the older patients with orthopedic trauma admitted to our department between January 2021 and January 2022. Patients were identified with sarcopenia if they have both low hand grip strength (HGS) and low appendicular skeletal muscle mass (ASM). Propensity score matching (PSM) was performed to reduce the bias caused by the co-factors and levels of IL-16 between normal patients and patients with sarcopenia were compared. In animal research, mice were treated with IL-16 to identify the effects of IL-16 on muscle function and muscle mass. Then the sarcopenia models were established and the anti-IL-16 was performed to identify the potential therapeutical effect of targeting IL-16.

[RESULTS] 421 individuals were included in the clinical study, and 77 were identified as sarcopenia. In the matched populations, the serum levels of IL-16 of individuals with low HGS, ASM, and sarcopenia were significantly higher than normal individuals (all p < 0.001). The mice treated with IL-16 showed significantly impaired muscle function and physical performance and loss of muscle mass. Using anti-IL-16 antibodies may rescue the sarcopenia traits caused by botulinum toxin type A.

[CONCLUSION] Individuals with high levels of IL-16 may have a significantly high risk of sarcopenia. IL-16 impairs muscle function and physical performance and leads to muscle atrophy in mice, and these effects could be reduced by targeting IL-16.