L-24   GROWING HAIR IN THE LABORATORY: WHERE ARE WE NOW?

BA Bernard. L'Oréal Recherche, Clichy, France.

In a pioneer work (J.Cell Science, 1990, 97:463-471), M.Philpott demonstrated that human hair follicle could be grown in vitro, in a totally defined medium. Since then, this system has been extensively used to evidence unique features of human hair follicle. This organ is indeed endowed with a surprisingly stable homeostasis as it can grow for weeks, in the absence of its natural environment. Its gross structure is well preserved with time as shown by histology and immunohistochemistry. The growth rate and differentiation patterns are maintained, while the shaft is properly built up and organized, as evidenced by X-ray diffraction and keratin expression. Moreover, the hair follicle metabolic activity can easily be studied, as well as gene expression. More specifically, we and others have demonstrated, in this in vitro system, the modulation of hair growth by growth factors, cytokines, or hormones. We thus believe that the hair follicle grown in vitro represents a unique and versatile tool for pharmacological study of hair biology.