Use of a collagen/elastin-membrane for the tissue engineering of dermis

In an experimental model in rats, xenogeneic membranes consisting of processed native collagen and elastin were grafted to serve as a template for the formation of a neo-dermis, while in vitro-cultured autogeneic keratinocytes were applied on top of this to restore an epidermis. The process of tissue reconstruction and the digestion of the grafted membrane components were analysed by histological and immunohistochemical methods as well as electron microscopy. Approximately 3 weeks post grafting the membranes were completely vascularised and colonized by different types of cells. After 6 weeks, the collagenous fibres of the graft were mostly replaced by newly formed collagenous texture, whereas elastic membrane components were still present even after 20 weeks. In a second step, in vitro-cultured keratinocytes were applied onto the partially integrated membranes, resulting in an epithelial coverage of approximately 47% of the grafted area after 8-11 days. As early as on day 6 post application, a multilayered, partially differentiated epithelium, together with lymphocytes and Langerhans' cells, could be observed. After 10 days the formation of a basement membrane including anchoring fibrils appeared to be complete. This three-dimensional matrix structure offers a promising scaffold for a tissue engineering strategy to restore skin structure and function. Further experimental studies are in progress to test its applicability to human skin replacement.