Culture of human urothelial cells on a cell-free dermis for autotransplantation

Objective: Techniques for in vitro culturing and autotransplantation have been developed for a variety of human cells and are used today in several fields of medicine. In reconstructive surgery within the genitourinary tract, autologous urothelial cells cultured in vitro could be of considerable value but have not yet been used clinically. The aim of this study was to facilitate transplantation of cultured urothelium by establishing a reliable method for culturing urothel on an immunologically inert and biodegradable structure. Methods: Normal human urothelial cells were cultured in vitro using a feeder-cell system. To achieve an optimal carrier structure, cells were removed enzymatically from a split thickness skin graft. Human urothelial cells were then seeded on the cell-free dermis and incubated in vitro. The seeded dermis samples were investigated histologically and with immunohistochemical methods at days 7, 14 and 21. Results: The human urothelial cells incubated in vitro reached confluence after 7-10 days and the cells could be cultured through 9 passages with preserved proliferative potential. When the cells were seeded on a cell-free dermis they attached, formed colonies and became confluent and stratified up to three cell layers after 21 days of incubation. The urothelial origin of the cells was confirmed by immunohistochemical staining against cytokeratin. Conclusion: The advantages of culturing the urothelial cells on a cell-free dermis include a short time lag until grafts are available, probably facilitated transplantation procedure, transplantation of undifferentiated cells and the formation of a vascularised base under the new urothelium. The method described in this study may be of great value in providing autologous urothelium for reconstructive surgery in the genitourinary tract.