The objective of this study was to demonstrate that stem cells isolated from discarded skin obtained after
debridement can be used with
collagen and
fibrin-based scaffolds to develop a tissue-engineered vascularized dermal equivalent. Discarded tissue samples were collected from severely burned patients undergoing
wound debridement. Stem cells were isolated from the adipose tissue layer and their growth and immunophenotype characterized. To develop a skin equivalent, debrided skin adipose stem cells (dsASCs) were added to a
collagen-
polyethylene glycol (PEG)
fibrin-based bilayer
hydrogel and analyzed in vitro. The effect of the bilayered
hydrogels on wound healing was demonstrated using an excision
wound model in athymic rats. The dsASCs isolated from all samples were CD90, CD105, and stromal cell surface protein-1 positive, similar to adipose stem cells isolated from normal human lipoaspirates. Within the bilayer
hydrogels, dsASCs proliferated and differentiated, maintained a spindle-shaped morphology in
collagen, and developed a tubular microvascular network in the PEGylated
fibrin. Rat excision
wounds treated with bilayer
hydrogels showed less
wound contraction and exhibited better dermal matrix deposition and epithelial margin progression than controls. Stem cells can be isolated from the adipose layer of burned skin obtained during
debridement. When dsASCs are incorporated within
collagen-PEGylated
fibrin bilayer
hydrogels, they develop stromal and vascular phenotypes through matrix-directed differentiation without use of
growth factors. Preliminary in vivo studies indicate that dsASC-bilayer
hydrogels contribute significantly to wound healing and provide support for their use as a vascularized dermal substitute for skin regeneration to treat large surface area
burns.