Human hair follicle regeneration following amputation and grafting into the nude mouse

In this study we investigated the capacity of the human hair follicle to regenerate a fiber-forming bulb after its amputation. We removed the bases from terminal follicles from a variety of sites and transplanted the follicles onto athymic mice, either still attached to a skin graft or as subcutaneous implants of individual follicles. External hair growth was observed on the skin grafts, and histology of the follicles revealed restoration of dermal papillae and follicle bulb structures. This result suggests that the capacity of hair follicles to regenerate their lower structures after removal, which was first demonstrated on whisker follicles, may be a general phenomenon. It emphasizes the importance of specific cellular subpopulations within the follicle and the role of dermal-epidermal interactions in adult follicle activities.