RESUMO
BACKGROUND: Human corneal endothelial cells undergo very little or no proliferation and respond to cell loss by migration and cellular enlargement. Significant cell loss or damage may result in corneal oedema, opacity and loss of vision. In vitro expansion of corneal endothelial cells (CECs) is a promising strategy for corneal regeneration. The transition zone (TZ) may be an alternative source of CECs. The objective of this study was to establish a protocol for TZ cell culture, and to determine their potential to proliferate and differentiate into cells that resemble CECs in vitro. METHODS: An explant culture protocol for the human TZ was established. Cell proliferation was assessed using 5-ethynyl-2'-deoxyuridine (EdU) assay. The expression of stem cell and endothelial markers was assessed using immunohistochemistry and quantitative polymerase chain reaction. RESULTS: TZ cells can be passaged up to 12 times; cells became polygonal 3 to 4 passages before senescence. An average of 41% of cells incorporated EdU over a 5-day period. TZ cells expressed the corneal endothelial proteins ZO-1 and Na+ /K+ ATPase, Col8A2, the periocular mesenchyme marker PITX2, and the neural crest stem cell markers Nestin and Sox10. TZ cells expressed mRNA of a range of neural crest, periocular mesenchyme, and corneal endothelial genes. CONCLUSIONS: TZ cells can proliferate and differentiate into cells that resemble CECs, demonstrating their potential to be an alternative cell source for corneal endothelial cell therapy.
