Bulge Cells of Human Hair Follicles: Segregation, Cultivation, and Properties

In the 2006 study by Zhang et al., researchers isolated and cultured bulge cells from human anagen hair follicles to investigate their properties as hair follicle stem cells (HFSCs). The cultured cells proliferated rapidly, with proliferation observed as early as day 2, peaking at day 6, and maintaining higher levels for several days. These cells exhibited undifferentiated features and expressed HFSC markers K19 and ß1-integrin, although these markers decreased over time in culture. The study confirmed that bulge cells are distinct from outer root sheath cells, with a higher colony-forming efficiency and the ability to generate the lower follicle and hair. The findings support the "Bulge Activation Hypothesis," suggesting that bulge-derived cells in vitro represent HFSCs in vivo, and highlight the potential of these cells for use in various dermatological applications. The number of hair follicles or bulge cells used was not specified in the summary.