Background: The umbilical cord epithelium (UCE) is composed of a single epithelial layer covering mucous connective tissue and it is thought to derive from the amniotic epithelium. Interestingly, UCE cells express not only simple and mucous epithelial keratins (CK8 and CK4/CK13), but also stratified epithelial keratins (CK1/10) and cornified cell envelope (CCE)-associated proteins.
Objective: To understand the nature of UCE, UCE cells were cultured under the same conditions of organotypic culture of epidermal keratinocytes and grafted onto the back of nude mice.
Methods: UCE cells isolated from fresh umbilical cord specimens were cultured using serum-free keratinocyte growth medium, and plated on a fibroblast-populated collagen matrix using air-liquid interface methods. UCE cells were transplanted onto the back of Balb C nu/nu mice as a thin epithelial sheet grown on a collagen matrix.
Results: UCE cells formed a multi-layered stratified epithelium both in organotypic culture and surface transplantation. Regarding the expression profile of differentiation-specific proteins, such as keratins, the CCE-precursor proteins and junctional proteins, the reconstructed epithelium showed a close similarity to natural epidermis in organotypic culture.
Conclusion: These results suggest the possibility that UCE cells can differentiate and organize into an epidermis-like structure, when exposed to the appropriate conditions which is similar to those of cutaneous epidermis.
Copyright 2004 Japanese Society for Investigative Dermatology