Human Hair Growth In Vitro: A Model for the Study of Hair Follicle Biology

The study developed an in vitro model for human hair growth, successfully maintaining isolated hair follicles for up to 10 days with continued growth at an in vivo rate. It was observed that epidermal growth factor (EGF) stimulated outer root sheath cell proliferation, disrupting normal cell interactions, similar to its depilatory action in sheep. Transforming growth factor-β (TGF-β) was identified as a potential negative regulator of hair growth, while insulin-like growth factor-I (IGF-I) supported hair growth at physiological levels, preventing premature entry into a catagen-like state without insulin. Additionally, the study found that hair follicles are aerobic glycolytic and glutaminolytic tissues, indicating specific metabolic implications.