The requirement for basement membrane antigens in the production of human epidermal/dermal composites in vitro

The importance of a dermal element when providing permanent wound cover for skin loss has become evident as the shortcomings of pure epidermal grafts are recognized. We are developing a skin composite formed from sterilized h uman de-epidermized acellular dermis, keratinocytes and fibroblasts with th e ultimate aim of using this composite to cover full-thickness excised burn wounds. These composites can be prepared with or without basement membrane (BM) antigens initially present on the dermis. This study investigates the importance of retaining BM antigens on the dermis to the production and ap pearance of these composites in vitro. Skin composites prepared from dermis with BM antigens either present or absent initially were studied throughou t 3 weeks. Composites with BM antigens present initially were significantly better than those initially lacking BM antigens in: (i) the degree of epit helial cell attachment to the underlying dermis (hemidesmosomes were seen o nly in the former); (ii) the morphology of the epithelial layer; (iii) the consistent presence of collagen IV and laminin and the increasing expressio n of tenascin; and (iv) the amount of soluble collagen TV and fibronectin d etected in the conditioned media. We conclude that an initial BM antigen te mplate is vital in this skin composite model for the attachment and differe ntiation of the epithelial layer and for the subsequent remodelling of the BM in vitro.