Effects of estrogen on rhesus retinal endothelial cell proliferation by increasing expression of estrogen receptor-beta, and decreasing expression of angiogenic, anti-angiogenic cytokine release

Diabetic retinopathy is a leading cause of blindness occurring due to progressive damage of retina. Estrogens are steroids responsible for growth, maintenance, regulation and proliferation of cells. Increase in estrogen levels during puberty are known to cause diabetic retinopathy in an unknown manner. Retinopathy occurs due to neovascularization in retina. We studied the effects of estrogen on retinal endothelial cell proliferation and observed an increase in proliferation with concentration and time. Also we found that the estrogen increases its receptor expression to increase the cell proliferation. Cell proliferation due to estrogen is mediated by both PI3K and MAPK pathways and also by down regulating the expression of VEGF and PEDF cytokines. These results indicate that estrogen plays a very important role in the cell proliferation of endothelial cells and also can regulate its receptor expression to increase its activity. Furthermore studies may reveal the mechanism through which estrogen induces its proliferation and can help in drug development to prevent the endothelial cell proliferation, the key feature of retinal angiogenesis.