Treatment of burns and donor sites with human allogeneic keratinocytes grown on acellular pig dermis

The absence of a dermal component predisposes cultured epidermal sheets to instability, contractibility, and makes them difficult to handle. In order to overcome these drawbacks, we developed recombined human/pig skin (RHPS) composed of human keratinocytes cultured on cell-free pig dermis. The original intention to prepare a permanent skin substitute composed of xenodermis and autologous epidermis was not achieved, but it has been proved that RHPS can serve as an effective, ready to use keratinocyte delivery system when applied 'upside-down', i.e. with epidermal cells facing the wound surface. The keratinocyte layer establishes a direct contact with the wound bed, while the dermal layer mechanically protects the wound. Twenty deep dermal burns were grafted with RHPS: 13 (65%) healed completely in 4-14 days, three (15%) healed partially and four (20%) did not heal. Of five full thickness burn wounds only one healed after repeated RHPS grafting within 18 days. Thirty-one (100%) donor sites treated with any of the three forms of RHPS, subconfluent, confluent meshed or confluent unmeshed, healed within 6-8 days compared with 14-18 days in control sites. Seven donor sites (100%) of immunodeficient patients with prolonged wound healing epithelialized in 7-10 days under RHPS compared with 32-90 days in areas treated with tulle gras and dry gauze.