453 Signaling by Senescent Melanocytes Induces New Hair Growth and Informs Hair Growth-Activating Injectable for Androgenetic Alopecia

The study investigates the role of senescent melanocytes in promoting hair growth, particularly in the context of androgenetic alopecia. Researchers found that senescent melanocytes in hairy nevi upregulate signaling genes like Osteopontin (SPP1), which interacts with the CD44 receptor on hair stem cells, enhancing hair growth. Using mouse models, they demonstrated that hair growth depends on intact SPP1 and CD44 genes. Recombinant SPP1 protein was shown to trigger hair cycle entry in both mouse and human hair follicles. Inspired by these findings, a new injectable polysaccharide, AMP-303, was developed. In a randomized, double-blind study involving males aged 18-45 with androgenetic alopecia, AMP-303 injections led to a 15.7% increase in non-vellus hair count at 60 days and 13.7% at 150 days post-treatment compared to placebo. The treatment was well-tolerated with mild and rare adverse events, suggesting potential for AMP-303 as a therapeutic for hair growth in androgenetic alopecia.