CHARACTERIZATION OF EPIDERMAL WOUND-HEALING IN A HUMAN SKIN ORGAN-CULTURE MODEL - ACCELERATION BY TRANSPLANTED KERATINOCYTES

Few data are available on early regeneration of human epidermis in viv o. We have established a supravital skin organ culture model for epide rmal wound healing by setting a central defect (3 mm diameter) in fres hly excised skin specimens and culturing under air exposure. Reepithel ialization was followed for up to 7 d by histology and immunohistologi c analysis of various markers for differentiation and proliferation. I n 12 of 19 cases (63%; 5% fetal calf serum) or six of 21 cases (29%; 2 % fetal calf serum), the wounds were re-epithelialized spontaneously a fter 7 d, After transplantation to the wounds of 1-2 x 10(6) dissociat ed allogenic cultured epidermaf. or about 1 x 10(6) autologous outer r oot sheath keratinocytes, 18 of 21 cases (86%; 5% fetal calf serum) or 17 of 21 cases (81%; 2% fetal calf serum) were healed within the same period. Histologically, early neoepithelium (3 d) was disordered afte r keratinocyte transplantation, whereas later (7 d) it had gained a mo re ordered stratification, exhibiting a thin discontinuous granular an d a compact horny layer. At this stage, not only hyperproliferative (C K 6) but also, abundantly, maturation-associated cytokeratins (CK i, C K 10) were detected immunohistochemically. Analyses of regenerated epi dermis after transplantation of (i) keratinocytes labeled in vitro wit h BrdU and (ii) heterosexual keratinocytes by immunohistochemistry and fluorescence in silw hybridization for the Y chromosome, respectively , clearly showed that external keratinocytes are physically integrated into the regenerated epidermis and extendedly contribute to its forma tion. The data presented here demonstrate improvement and acceleration of epidermal re-epithelialization by transplantation ofkeratinocytes.