Epidermal stem cells to construct tissue-engineered skin to promote vascularization of dermal substitutes and a single-stage transplantation in vivo study

Composite transplantation of STSG(split-thickness skin graft) combined with acellular dermal matrix (ADM) is a promising repair method for full-thickness skin defects.Till date, there is no available engineered skin tissue able to permanently cover full thickness in a one-stage procedure.Due to delayed vascularization of ADM, a two-step procedure is often used to implant ADM in the first step and then implant STSG after full vascularization of ADM, resulting in increased treatment time and cost. Adipose stem cells (ASCs) and dermal stem cells (DSCs) promote vascularization of wound and dermal substitutes, while epidermal stem cells (EpSCs) originating from the basement layer of the skin are relatively rarely studied in tissue-engineered skin.Here, we investigated the effect of tissue engineered skin constructed with EpSCs on wound repair and its mechanism of promoting vascularization. By means of transcriptome sequencing showed that active substances secreted by ADM-cultured EpSCs promoted angiogenesis.It was found that EpSCs promoted epithelialization of the ADM surface and the generation of appendages such as hair follicles in vivo experiment. It was also found that EpSCs promoted vascularization of the full thickness of the ADM sheet for about 1 week. Next, we innovatively construct a novel tissue-engineered skin used ADM, STSG, and EpSCs combined (ASE) for one-step transplantation to repair the full-thickness skin wound in rats.The results showed that the ASE group significantly increased the survival and healing quality of the skin graft, reduced skin contraction, and improved the cosmetic appearance compared with the AS group and the STSG control group.In summary, our findings suggest that EpSCs can promote the formation of new blood vessels in dermal substitutes and can achieve one-step transplantation of composite skin, providing new ideas for the clinical treatment of one-step composite skin grafting.