Human allogeneic keratinocytes cultured on acellular xenodermis: the use in healing of burns and other skin defects.

The tissue engineered skin should be composed of both dermal and epidermal layers. We combined cultured human allogeneic keratinocytes with acellular xenodermis prepared from pig xenografts. The resulting composite skin was termed recombined human/pig skin (RHPS), and could be cultured in both, undifferentiated and differentiated phenotype. The undifferentiated RHPS was grown submerged and formed 1-2 layers of keratinocytes. The differentiated phenotype (D-RHPS) was grown at the air-liquid interface and formed 5-20 cell layers similar to the normal epidermis, including the granular and horny layers. Undifferentiated RHPS has skin-like consistency and has been successfully used for treatment of burns and skin defects using "upside-down" application. Donor sites and deep dermal burn wounds prepared by tangential excision or deep dermabrasion grafted with RHPS healed in the course of about one week after keratinocyte transplantation. Simple acellular xenodermis without keratinocytes can also be used as temporary cover for donor sites, small to medium leg ulcers and other skin defects. Xenodermis can be fully sterilized and stored at the room temperature.