DESIGN OF AN ARTIFICIAL SKIN - IV - USE OF ISLAND GRAFT TO ISOLATE ORGAN REGENERATION FROM SCAR SYNTHESIS AND OTHER PROCESSES LEADING TO SKIN WOUND CLOSURE

Deep skin wounds in the adult mammal close spontaneously by epithelial ization, wound contraction, and scar synthesis. In previous wound heal ing studies, it has been unsuccessfully attempted to separate from eac h other the natural processes that close wounds. In this study, we att empted to isolate skin regeneration from spontaneous processes of woun d closure using ''island'' grafts. A porous analog of the extracellula r matrix, composed of a graft copolymer of type I collagen and chondro itin 6-sulfate, was seeded with uncultured autologous keratinocytes an d served to induce regeneration of the dermis and the epidermis. Graft s of the copolymer, measuring 1 x 2 cm, were placed in the center of 5 x 6-cm wounds in guinea pigs. By day 14, the edges of the island graf ts were clearly separated from the host epidermis and dermis by a dist inct bed of granulation tissue. Histologic study of island grafts on d ay 14 showed that the copolymer grafts had largely degraded and that a new epidermis and dermis had been synthesized in its place. The thick ness of the new epidermis increased as the density of cells seeded int o the graft increased. No synthesis of epidermis or dermis was observe d in the granulation tissue outside the perimeter of the island grafts . We conclude that island grafting allows the study of early events in skin regeneration in isolation from epithelialization, contraction, a nd scar synthesis. (C) 1998 John Wiley & Sons, Inc.