Mesenchymal Stem-Cells Patches Improve Burn Wound Reepithelization in a Porcine Wound Model: A Prospective, Comparative Study

Background: Delayed burn wound healing leads to increased morbidity, painful and unsightly scars. It is attributed to prolonged systemic and wound inflammation, vascular damage and hypoxia. Among current therapies, semi-occlusive dressings provide a moist environment, and cultured keratinocytes moderately hasten epithelization; however neither can control the pro-inflammatory response. Stem cells, in particular mesenchymal, accelerate the healing process. They promote local cell proliferation, tissue regeneration and angiogenesis. Their immuno-modulatory and anti-inflammatory properties allow for transplantation without histocompatibility matching. There are no pre-fabricated stem cell patches commercially available. We experimented with a tissue-engineered patch that delivers allogenic mesenchymal stem-cellsderived from the human endometrium— nested on a collagen scaffold; we assessed its effects on reeptithelization rates on burn wounds compared to semi-occlusive dressings and keratinocyte patches. Methods: In a swine model burn wounds were made with a hot plate. Each was covered with either a semi-occlusive dressing, a cultured keratinocyte patch, or stem-cell patch. A grading scale was developed for histologic findings for stratum corneum, epidermis and dermis. Results: There was no significant difference between semi-occlusive and keratinocyte patches. There was significant difference between stem-cell patches and semi-occlusive patches on all layers. Stem-cell patches were superior to keratinocytes only on the dermal layer. Conclusions: Endometrium derived mesenchymal stem-cells are abundant and easy to harvest for prefabrication of live cellular dressings. They promote a faster and more organized wound healing, even in cross-species grafting.