Successful transplantation of cultured human outer root sheath cells as epithelium

We used sheets of cultured outer root sheath cells derived from plucked human hair follicles for the epidermal reconstruction of a burn wound of a patient and prepared wounds of athymic mice. The outer root sheath cells obtained from plucked human follicles can grow in serial culture in a defined medium without serum. After seven subcultures within 5 weeks, outer root sheath cells obtained from a single follicle grew approximately 1 x 10(7) cells, which covered a 360-cm2 area of a monolayer sheet. These cultured outer root sheath cells, carried on a bovine atelocollagen sheet (Meipac) or a polyurethane sheet (Tegaderm), were transplanted on a graft bed prepared on the backs of athymic mice. Contraction of the graft beds was prevented by the use of these carriers. Histological examination of the graft removed 2 weeks after transplantation showed four to seven layers of epithelial cells. Both the epidermal granular and horny cell layers were well developed, although the rete ridges were absent. Using the same technique, the sheet of outer root sheath cells with an atelocollagen as a carrier was successfully transplanted onto the granulating site in a burn patient.