Development of a dermal matrix from glycerol preserved allogeneic skin

Dermal substitutes can be used to improve the wound healing of deep burns when placed underneath expanded, thin autologous skin grafts. Such dermal matrix material can be derived from xenogeneic or human tissue. Antigenic structures, such as cells and hairs must be removed to avoid adverse inflammatory response after implantation. In this study, a cost-effective method using low concentrations of NaOH for the de-cellularization of human donor skin preserved in 85% glycerol is described. The donor skin was incubated into NaOH for different time periods; 2, 4, 6 or 8 weeks. These dermal matrix prototypes were analyzed using standard histology techniques. Functional tests were performed in a rat subcutaneous implant model and in a porcine transplantation model; the prototypes were placed in full thickness excision wounds covered with autologous skin grafts.An incubation period of 6 weeks was most optimal, longer periods caused damage to the collagen fibers. Elastin fibers were well preserved. All prototypes showed intact biocompatibility in the rat model by the presence of ingrowing blood vessels and fibroblasts at 4 weeks after implantation. An inflammatory response was observed in the prototypes that were treated for only 2 or 4 weeks with NaOH. The prototypes treated with 6 or 8 weeks NaOH were capable to reduce wound contraction in the porcine model. In neo-dermis of these wounds, elastin fibers derived from the prototype could be observed at 8 weeks after operation, surrounded by more random orientated collagen fibers. Thus, using this effective low cost method, a dermal matrix can be obtained from human donor skin. Further clinical studies will be performed to test this material for dermal substitution in deep (burn) wounds.