Morphological Analysis of In Vitro Human Hair Growth

The study evaluated the histological and ultrastructural aspects of normal human hair follicles maintained ex vivo for 12 days in a serum-free medium. Anagen hair follicles showed continued viability and growth for up to 8 days, maintaining normal in vivo morphologies, including functional hair bulb melanocytes. After 8 days, signs of follicular cell interaction loss and impending involution were observed, with most follicles involuting by 12 days, displaying apoptotic-like keratinocytes and highly keratinized hair structures. The study provided the first detailed histological and ultrastructural analysis of human hair follicles in culture, suggesting that while some features of catagen were present, the mechanisms might differ.