Differential Expression of Stem Cell Markers in Human Follicular Bulge and Interfollicular Epidermal Compartments

The study, conducted 14 years ago, aimed to identify specific stem cell markers to distinguish between stem cells in the interfollicular epidermis (IFE) and the bulge region of human scalp hair follicles. Using immunohistochemistry and multicolor immunofluorescence on samples from five donors, the researchers found that CD34 and CD117 were expressed in the basal IFE but not in the bulge, while CD200 was present in the bulge but not the basal IFE. CK15, CD29, and CD49f were expressed in both areas, and CD71 or CD24 were not expressed in either, suggesting their use as negative selection markers. CD90 was found in dermal papilla cells but not in basal IFE or bulge stem cells, indicating its potential as a positive selection marker for dermal hair follicle stem cells. The findings could aid in developing strategies for cell sorting and purification to understand the molecular signatures of each stem cell population, which is important for treating alopecia. The study was supported by the Minnesota Jewish Foundation and an ASDS Cutting Edge Grant.