Hair regeneration: Mechano-activation and related therapeutic approaches

Hair regrowth through mechano-stimulation and other therapeutic approaches has emerged as a significant area of research in regenerative medicine. This review examines recent advances in hair regeneration strategies, with a particular focus on mechanical stimulation and complementary treatments. Studies have demonstrated that skin stretching can activate hair follicle stem cells and promote hair growth under specific conditions and durations. This process involves intricate signaling interactions, particularly through the WNT and BMP pathways, and follows a two-stage mechanism that recruits and modulates the function of macrophages. Mechanical stimulation induces the release of growth factors such as HGF and IGF-1, which activate stem cells and support hair follicle regeneration. Beyond mechanical activation, emerging hair restoration therapies, including MSC transplantation, MSC secretome therapy, and platelet-rich plasma treatments, have shown promising results. These innovative strategies overcome the limitations of conventional therapies, offering effective solutions for various types of hair loss. Additionally, here we discuss the molecular mechanisms underlying hair follicle growth and repair, the influence of external factors, and novel hair follicle formation processes, such as chimeric follicle development and follicular neogenesis. Special attention is given to the roles of dermal papilla cells and their interactions with mesenchymal cells in promoting hair regrowth. The key strategies and underlying mechanisms discussed in this review will drive future research and potential clinical applications.