SKIN ANATOMY AND ANTIGEN EXPRESSION AFTER BURN WOUND CLOSURE WITH COMPOSITE GRAFTS OF CULTURED SKIN CELLS AND BIOPOLYMERS

Closure of large skin wounds (i.e., burns, congenital giant nevus, reconstruction of traumatic injury) with split-thickness skin grafts requires extensive harvesting of autologous skin. Composite grafts consisting of collagen-glycosaminoglycan (GAG) substrates populated with cultured dermal fibroblasts and epidermal keratinocytes were tested in a pilot study on full-thickness burn wounds of three patients as an alternative to split-thickness skin. Light microscopy and transmission electron microscopy showed regeneration of epidermal and dermal tissue by 2 weeks, with degradation of the collagen-GAG implant associated with low numbers of leukocytes, and deposition of new collagen by fibroblasts. Complete basement membrane, including anchoring fibrils and anchoring plaques, is formed by 2 weeks, is mature by 3 months, and accounts for the absence of blistering of healed epidermis. All skin antigens tested (involucrin, filaggrin, laminin, collagens IV and VII, fibronectin, and chondroitin-sulfate) were expressed by 16 days after grafting. This cultured skin analogue provides an experimental alternative to split-thickness skin graft that develops histiotypic markers of skin anatomy and antigen expression after wound closure.