In vitro production and subsequent transplantation of a living skin substitute in rat model.

Three different transplants were generated for in vitro production of a living skin substitute in a rat animal model. In all cases epithelial cells from a small skin biopsy were grown in cell culture. Compound 1 consisted of cells outgrowing on lyophilized human dura mater. Compound 2 was fabricated with lyophilized porcine dermis. In compound 3 a lamella of dehydrated human fascia lata was seeded with epidermal cells. These skin substitutes were used to cover full-thickness skin defects. The production of a 6 cm2 substitute required 4-5 weeks time. After grafting autologous skin substitutes from compounds 1 and 2, vascularization and integration of the grafts failed to occur with 3 weeks. In contrast, transplantation of compound 3 resulted in the complete epithelialization of wound beds within 2-3 weeks accompanied by permanent integration of the skin substitute. Histological examination 1 year after grafting showed a dense, uniform structure of collagen fibers with an overlying epithelium of 4-6 cell layers. Secondary derivatives such as hair follicles and sweat glands were absent. When the fascia in compound 3 was replaced by a collagen lattice populated with cultured fibroblasts, transplantation results were unsatisfactory because of the deficient tensile strength of the collagen lattice.