Progenitor Cells in Healing after Pterygium Excision

Bone marrow derived progenitor cells were reported to be involved in the pathogenesis of pterygium and have been suggested to be important in angiogenesis and the repair process after tissue damage. In order to investigate the involvement of these cells in wound healing after a pterygium excision, immunohistochemical staining was performed with a temporary amniotic membrane, applied to the bare sclera, after a pterygium excision using various progenitor cell markers, including CD34, c-kit, STRO-1, and AC133, to determine the expression levels of the participating cells. CD34-positive cells were observed along with some round or spindle-shaped mononuclear cells on the stromal side of the amniotic membrane. Some CD34-positive, large, and round or spindle-shaped cells formed clusters resembling small vessels in some regions of the amniotic membrane. c-kit was expressed in the epithelium that had grown over the amniotic membrane and in the spindle-shaped or round mononuclear cells in the stroma. Many stellate- to spindle-shaped fibroblast like cells expressed STRO-1, and AC133 was expressed in some round and ovoid cells. Overall, these results suggest that adult bone marrow- derived progenitor cells, such as endothelial progenitor cells and mesenchymal stem cells, are involved in the wound healing process post-excision in patients with pterygium.