Transplantation and Fate of Tissue Engineered Skins Comprising Human Epidermal Stem Cells and Acellular Amniotic Membrane

Tissue engineered skins have the potential to overcome the limitations of present large area of skin replacements. To achieve this, we investigated the effect and fate of tissue engineered skins comprising human epidermal stem cells and acellular amniotic membrane after their transplantation to full-thickness skin defect wound, so as to lay a foundation for clinic application. The human epidermal stem cells was isolated from the skin samples by trypsin digesting method and purified by collagen adhering method, and then seeded on the acellular amniotic membrane and cultured in the keratinocyte serum free medium in present of the epidermal growth factor to form the tissue engineered skin. Eighteen New Zealand white rabbit with full thickness skin defect on the back were grafted with the tissue engineered skin (experimental grafted group), single acellular amniotic membrane(control group 1) and no treated (control group 2),respectively. The wound healing conditions were observed and wound contraction rate were calculated. Histological changes were undertaken by tissue sampling from the grafted wound. The expression of CK19 and HLA-DR were detected by the immunohistochemistry methods. The results showed that the grafted wounds in experimental group healed very well with good external appearance and elasticity. The wound contraction rate in experimental grafted group, control group 1 and control group 2 was 22.6 plusmn 1.54%, 29.3 plusmn 1.41 % and 30.4 plusmn 1.58 %, respectively. There were significantly different between experimental grafted groups and control group(P<0.05). No obvious immune rejection and any bleeding, suppuration or infection under all the grafted skins. There were full differentiation of epithelium and orderly collagen proliferation in experimental grafted wounds by histological examination. The expression of CK19 and HLA-DR were positive in the experimental grafted wounds, which were negative in the control group. This study suggest that the s- kin grafting with tissue engineered skins comprising human epidermal stem cells and acellular amniotic membrane could improve wound healing quality prominently, which maybe an ideal skin substitute with good histocompatibility.