Melanocyte Subpopulation Turnover During the Human Hair Cycle: An Immunohistochemical Study
August 2000
in “
Pigment cell research
”
melanocytes hair cycle immunohistochemical methods tyrosinase tyrosinase-related protein-1 TRP-1 anagen phase catagen phase telogen phase epithelial column dermal papilla melanogenesis melanogenic enzymes melanin hair growth cycle immunostaining melanin-producing enzyme melanin-related protein growth phase regression phase resting phase skin layer hair root melanin production melanin enzymes
TLDR Melanocyte activity in hair follicles is linked to the hair growth cycle, being active in growth phases and inactive in rest phases.
The study investigated the behavior of melanocytes in human hair follicles throughout the hair cycle using immunohistochemical methods. It was found that tyrosinase and tyrosinase-related protein-1 (TRP-1), key enzymes in melanin production, were expressed in melanocytes located in the hair bulb during the anagen (growth) phase but not during the catagen (regression) phase, despite the presence of melanocytes. In the telogen (resting) phase, inactive melanocytes were identified. The study concluded that melanogenesis in human hair is closely linked to the hair cycle, specifically restricted to the anagen phase due to the expression of melanogenic enzymes rather than the regulation of tyrosinase activity. Additionally, melanocyte division and enzyme expression were observed only in the nascent bulb during early anagen, indicating a region-specific stimulation of melanocytes.
