Abstract
Purpose:
Angiogenin is originally identified as a tumor angiogenic factor, and its biological activity is extended to stimulating cell migration and proliferation, and more recently to promoting cell survival. Because angiogenesis and cell proliferation are well known prerequisites for tissue formation of pterygium, we investigated the expression profiles of angiogenin as a novel factor related with pathogenesis of pterygium.
Methods:
In cultured stromal fibroblasts and surface epithelial cells of pterygia (42 eyes) and normal conjunctiva (12 eyes) as a control group, angiogenin expression was analyzed by RT-PCR at mRNA level and by Western blotting at protein level. Immunohistochemistry was used to assess the localization of angiogenin-expressing cells in pterygia. The pattern of expression in cultured cells and excised tissues was comparatively evaluated according to representative clinical indices based on recurrency, grade based on pterygial body morphology (T1-T3) or vascularity (V1-V3), and disease activity.
Results:
Angiogenin expression was higher in the stromal fibroblasts than epithelial cells. In cultured fibroblasts of pterygia, the recurred, T3 grade or active (recurred or occurred within recent 6 months) pterygia revealed significantly higher expression than the others at both mRNA and protein levels. In immunohistochemistry, angiogenin was strongly expressed in stromal layer of active and recurred pterygia with T3 grade, especially at the perivascular area in contrast to scarce expression in normal conjunctiva. Pterygia with high vascularity had a tendency of relatively higher expression of angiogenin.
Conclusions:
Angiogenin expressed in pterygia might contribute to active stromal tissue formation with angiogenesis and further recurrence. This newly uncovered finding suggests the possible effect of angiogenin to stimulate the stromal fibroblasts to proliferate in pathogenesis of pterygium.
Keywords: 665 pterygium •
654 proliferation