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 (R)) 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.