Cultured epidermal autografts

Abstract

In the early 1950s Billingham and Reynolds 1 demonstrated that epidermal sheets and epidermal cell suspensions obtained after trypsinization could be used to cover superficial wounds in experimental animals. Subsequent experiments in the late 1960s and early 1970s by Karasek. 2 Karasek and Charlton, 3 Freeman and co-workers, 4 and Igel et al. 5 proposed that epidermal cells grown in tissue culture could feasibly be transplanted onto wounds and that such cells would continue to grow and differentiate in vivo. In the late 1970s, Rheinwald and Green 6 and Green et al. 7 developed a system of culturing difficult-to-grow keratinocytes on lethally irradiated fibroblasts derived from a well-known mouse line (3T3). This technique for growing keratinocytes in culture made it possible to successfully grow and expand relatively small numbers of these cells into multilayered epithelium suitable for grafting. Growing keratinocytes in the absence of feeder layers, collagen substrates, or adhesive glycoproteins was achieved in 1979 by Eisinger and colleagues. 8 Keratinocytes could be grown into differentiated multilayered epidermal sheets provided that the pH of the culture medium was decreased (≅ 5.6) and the seeding density was optimal (2.5 × 10 5 cells/cm 2). In 1980, Eisinger et al. 9 demonstrated that cultured epidermal autografts could be used to cover deep partial-thickness wounds on dogs, pigs, and mice. Although it has been demonstrated that cultured epidermal autografts can be successfully transplanted onto partial-thickness wounds, there is very little, if any, objective data evaluating their potential effect on the healing process. This study was undertaken to evaluate objectively and to compare (1) the effect of epidermal autografts (grown on 3T3 feeder layers or on plastic) and wound occlusion on the healing of controlled partial-thickness wounds and (2) the effect of epidermal autografts. a collagen matrix (with or without keratinocytes), and occlusion alone on the healing and contraction of full-thickness wounds in swine.