Reinnervation of hair follicle end organs and Meissner corpuscles in skin grafts of macaques

Abstract

Plugs of occipital hairy scalp and pieces of digital pads were transplanted to the frontal scalp of stump-tailed macaques (Macaca arctoides). Both types of grafts grew well and retained their original appearance for several years. We traced regrowth and reinnervation of hair follicles and Meissner corpuscles in sequential biopsy specimens of these grafts. Two weeks after transplantation, hair follicles in the grafts appeared to have lost all integrity but began to regrow after 4 weeks. The nerve and organs of hair follicles began to reappear at 8 weeks. Thereafter, grafts with large terminal hairs remained viable in the host bald frontal scalp for as long as 8 yr. In the digital skin grafts, the cytoskeleton of the Meissner corpuscles could be distinguished after 4 weeks; after 8 weeks nerves from the host tissue could be traced to the end organs. Perivascular nerve plexuses and nerves to the piloarrector muscles were clearly seen in both types of graft after 8 weeks.