Topical RT1640 Treatment Effectively Reverses Gray Hair and Stem Cell Loss in a Mouse Model of Radiation-Induced Canities

The study demonstrated that the topical treatment RT1640, which includes cyclosporine A, minoxidil, and RT175, effectively reversed gray hair and promoted hair growth in a mouse model of radiation-induced graying. RT1640 was more effective than cyclosporine A alone in regenerating the hair pigment system and expanding the melanocyte stem cell (McSC) pool. The combined activities of the three drugs were necessary for these effects, as RT175 alone could not induce hair cycling in vivo but could upregulate the melanogenic program in vitro. This research suggested that RT1640 could be a promising therapeutic strategy for addressing hair graying and McSC-related disorders associated with aging and disease.