[Experimental study on a skin substitute. Artificial dermis epidermised by human keratinocytes]

In patients with third-degree burns, plastic surgeons must meet emergent requirements for skin coverage. Conventional autografts do not provide enough substance to cover these patients, hence the interest of skin substitutes. The aim of our work is to achieve epidermization of an artificial dermis with a technique of culture of human keratocytes, thus producing in vitro a dermoepidermal skin substitute akin to normal skin, and to implant it in nude mice. Human keratocytes are grown in a definite medium (MCDB 153) on an artificial dermis based on type I and III collagen and glycosaminoglycans, and cross-linked with chitosan. Human keratocytes from thin skin were seeded on the artificial dermis after a last passage in culture fials. Cell density and the number of days in vitro were varied on patches of artificial dermis. After culture, the patches were transferred on nude mice. These were sacrificed on the 7th or 14th day. Cell recolonization of the artificial dermis was then studied, as well as the growth of the epidermis on deep-frozen histologic sections. Primary cultures on an artificial dermis did not show production of a satisfactory epidermis. In some animals grafted with artificial dermis epidermized in a secondary culture, we observed a structure similar to that of normal skin. This work allowed outlining the problems to slove and contemplating the solutions required to develop a total artificial skin.