Decellularized dermis in combination with cultivated keratinocytes in a short- and long-term animal experimental investigation.

Decellularized human dermis as a potentially ideal scaffold for dermal substitution in severe burns was examined in a two-staged animal experiment. In an initial step, an in vitro generated composite graft consisting of human keratinocytes and decellularized dermis (AlloDerm) was transplanted onto nude mice in a short-term trial (n = 20, 14 days). Subsequently, a combined one-step grafting of full thickness wounds with both decellularized dermis (in part preincubated with fibroblasts) and cultivated autologous keratinocytes as a cell suspension in fibrin glue was done in a long-term porcine animal model (n = 10, 6 months). In both series, macroscopic wound healing was evaluated by planimetry. Histological investigations included morphological as well as immunohistochemical parameters. The short-term study showed both successful integration of the composite grafts and reduction of wound contraction compared with the control group (epithelial grafts). The long-term porcine study displayed reduced myofibroblast formation and contraction in the wounds that had been treated with fibroblast-preincubated dermis. After 4 weeks, a decline of the structural integrity of the dermal matrix could be noticed. The utility of decellularized dermis as template for both dermal reconstitution and keratinocyte delivery vehicle was shown. The closure of full thickness wounds by a single-step combination of an autologous keratinocyte fibrin sealant suspension and acellular dermis in a pig animal model could be shown. Incorporation of fibroblasts led to reduced wound contraction but could not prevent the loss of dermal integrity. The engineered 'skin' remained viable and stable over a period of 6 months.

Tissue engineering of skin substitutes.

Cultivated epithelial autografts as multilayered thin sheets represent common standard in clinically applied tissue engineering substitutes, outnumbering all experimental alternatives. However, the unsatisfying short and long term results concerning mechanical stability and scarring demand for alternatives. Our group investigated cultivation and transplantation of cultured autologous keratinocytes as a single cell suspension in a fibrin sealant matrix in athymic mice in combination with allogenic skin grafting. We observed reliable wound reepithialization after a cultivation period of only 2 weeks. Additionally, we could allocate successful combination of a keratinocyte fibrin sealant suspension and acellular dermis in an attempt to regenerate full thickness skin defects in a pig animal model. The potential clinical implication of subconfluently cultured keratinocytes is enhanced by the possibility of co-transplantation with decellularized dermis.

[Skin tissue engineering]. / Gewebeersatz (tissue engineering) von Dermis und Epidermis.

Cultivated epithelial autografts as multilayered, thin sheets represent a common standard in clinically applied tissue engineering substitutes, outnumbering all experimental alternatives. However, the unsatisfying short- and long-term results concerning mechanical stability and scarring require alternatives. The cultivation and transplantation of cultured autologous keratinocytes as a single cell suspension in a fibrin matrix, combined with allogenic skin grafting, has been investigated extensively in athymic nude mice. Wounds can be reliably reepithelialized after a cultivation period of only 14 days. Moreover, the successful combination of keratinocyte fibrin suspension and acellular dermis in an attempt to regenerate full thickness skin defects in a pig model has been demonstrated. The usefulness of subconfluently cultured keratinocytes-which can be harvested very early and are easy to handle-is enhanced by cotransplantation with decellularized dermis.