Epithelial cell characteristics of cultured XXXX limbal explants.

@entity1 @entity16914 @entity4166 @entity495 @entity470 @entity4206 @entity2277
AIM: To determine the immunohistochemical characteristics of putative corneal epithelial stem cells remaining on limbal explants maintained in culture. METHODS: @entity1 limbal explant cultures were generated from 25 residual corneoscleral donor rims following penetrating keratoplasty. Serial sections of these explants were studied using immunohistochemical techniques with a panel of antibodies, on day 0 and 1, 2, and 3 weeks. RESULTS: The number of epithelial cells expressing @entity4166 and @entity2277 increased with duration in culture, while the number of cells expressing @entity16914 decreased. @entity495 expression was lost by 1 week in culture. @entity4206 was expressed by cells that had migrated around the explant and the number of @entity4206 positive cells decreased with longer duration in culture. The explants were initially negative for Ki67, but the epithelial cells were positive at 1 week, and expression of Ki67 was progressively lost with increasing duration in culture. The initial uniform staining of the epithelium for @entity470 and alpha enolase remained unchanged at 3 weeks. CONCLUSIONS: There is an expansion of less differentiated ( @entity16914 negative and @entity4166 / @entity2277 positive) epithelial cells on corneoscleral explants maintained in culture for 3 weeks. The pattern of expression of @entity4206 noted in this study does not support the suggestion that it is a marker of limbal stem cells. The decline in @entity4206 and Ki67 expression among the epithelial cells of the cultured explant button implies that as the epithelial sheet outgrowing from the explant button reaches confluence, the proliferative status of the cells remaining on the explant button declines. These findings are of clinical relevance as explants of limbal tissue are used in limbal stem cell transplantation. There is no information available to date on the fate of epithelial cells on such explants. This study provides some insight into this and suggests that an expansion of the stem cell pool or its progeny may occur in limbal explants.
