Involvement of Multipotential Progenitor Cells in Pterygium Pathogenesis

Abstract

Abstract: : Purpose.To evaluate the involvement of multipotential progenitor cells in the pathogenesis of pterygium. Methods. The paraffin-embedded and snap-frozen primary pterygium (n=20) and recurrent pterygium (n=10) were serially sectioned and analyzed immunohistochemically to determine the expression level of CD34 (marker for the hematopoietic progenitor cells and endothelium), c-Kit (marker for hematopoietic and stroma progenitor cells.), STRO-1 (a differentiation antigen present on bone marrow fibroblast cells and to various nonhematopoietic progenitor cells), VEGF (vascular endothelial growth factor) and α-SMA (α-smooth muscle actin). Results. Of all the primary pterygium, the immunoreactivity of CD34 was observed in the vascular endothelium and some scattered ovoidal cells in subepithelial connective tissue. C-Kit was expressed mainly in the basal epithelium of the head portions, and some spindle-shaped stroma cells. STRO-1 was expressed by spindle-shaped cells in subepithelial tissue. The immunostaining pattern of VEGF and α-SMA was closely correlated with the expression degree and the number of CD34 positive cells. There is no immunoreactivity of c-Kit and STRO-1 in normal conjunctiva while CD34 was mildly stained with vessel wall. Significantly increased CD34, c-Kit and STRO-1 positive cells were detected in all recurrent pterygium. Conclusions. Multipotential progenitor cells may involve in the pathogenesis of pterygium by being differentiated into fibroblasts and vascular endothelial cells.

Keywords: Pterygium • immunohistochemistry • microscopy: light/fluorescence/immunohistochem