A study of using tissue-engineered skin reconstructed by candidate epidermal stem cells to cover the nude mice with full-thickness skin defect.

OBJECTIVE: To study and explore the feasibility of using candidate epidermal stem cells with reconstruct tissue-engineered skin for a skin defect.
METHODS: After the candidate epidermal stem cells were selected directly by rapid adhesion to type IV collagen within 10min from keratinocytes isolated from foreskin epidermis, the TES was constructed by seeding large-scale cultured candidate epidermal stem cells onto a fibroblast-containing dermal substrate, then grafted onto athymic immunodeficient mice with full-thickness skin defects. All specimens were harvested after 1 week, 2 weeks and 4 weeks of transplantation to evaluate by gross, histological, transmission electron microscopic and immunohistochemical techniques its potential to reconstitute a full-thickness skin defect.
RESULTS: The transplanted skin developed a well-differentiated epidermis composed of stratum basale, prickle cell layer, granular layer and stratum corneum and clearly defined dermis with the morphological features of intact skin. The continuous and integral basement membrane zone (BMZ) was established; hemidesmosomes, basal lamina and anchoring fibrils were detected. In the dermis, the collagen of dermal substitute degraded gradually and fibroblasts were aligned in order; lymphocytes, organelle debris, differentiated microvasculature and hyperactive collagen fibrillogenesis were observed. The immunohistochemistry suggested that the keratinocytes of the TES were originated from the human candidate epidermal stem cells and not from the mice. The constructed TES was similar to the uninjured skin in morphological features, which suggested the constructed TES by combining cultured candidate epidermal stem cells with the dermal substrate could satisfy the need for the restoration of skin defects.