Magnetization of mesenchymal stem cells using magnetic liposomes enhances their retention and immunomodulatory efficacy in mouse inflamed skeletal muscle.

Sarcopenia, an age-related reduction in skeletal muscle mass and strength, is mainly caused by chronic inflammation. Because mesenchymal stem cells (MSCs) have the capacity to both promote myogenic cell differentiation and suppress inflammation, they are a promising candidate for sarcopenia treatment. In this study, to achieve the long-term retention of MSCs in skeletal muscle, we prepared magnetized MSCs using magnetic anionic liposome/atelocollagen complexes that we had previously developed, and evaluated their retention efficiency and immunomodulatory effects in mouse inflamed skeletal muscle. Mouse MSCs were efficiently magnetized by incubation with magnetic anionic liposome/atelocollagen complexes for 30 min under a magnetic field. The magnetized MSCs differentiated normally into osteoblasts and adipocytes. Additionally, non-magnetized MSCs and magnetized MSCs increased IL-6 and inducible nitric oxide synthase mRNA expression and decreased TNF-α and IL-1ß mRNA expression in C2C12 mouse skeletal muscle myotubes through paracrine effects. Moreover, magnetized MSCs were significantly retained in cell culture plates and mouse skeletal muscle after their local injection in the presence of a magnetic field. Furthermore, magnetized MSCs significantly increased IL-6 and IL-10 mRNA expression and decreased TNF-α and IL-1ß mRNA expression in inflamed skeletal muscle. These results suggest that magnetized MSCs may be useful for effective sarcopenia treatment.