depletion of cd200+ hair follicle stem cells in human prematurely gray hair follicles

Introduction: Melanocyte stem cells (MelSCs) are known to be depleted in gray hair follicles. Hair follicle stem cells (HFSCs) are important for maintenance of stemness of MelSCs. Methods: We compared the proportion of CD200+ (Cluster of Differentiation 200 positive) stem cells in the outer root sheath cell suspension of gray and pigmented hair follicles of three patients with the premature graying of hair. In addition, explants culture for HFSCs was also carried out from gray and pigmented hair follicles. Cultured HFSCs were also differentiated into melanocytes. Results: The mean ± SD CD200+ HFSCs population were 9.4 ± 1.4% and 3.5 ± 0.5% for pigmented and gray hair follicles, respectively ( P = 0.002). In explants culture, the growth of HFSCs from the gray hair follicle stopped at around day 20-22, whereas the growth of the cells from the pigmented follicle continued. Conclusion: CD200+ HFSCs are depleted in prematurely gray hair in the humans. CD200+ hair follicle stem cell yield is poorer in gray hair explant culture than pigmented hair explant culture.