Pigment Epithelium-Derived Factor: A Potent Inhibitor of Angiogenesis

In the absence of disease, the vasculature of the mammalian eye is quiescent, in part because of the action of angiogenic inhibitors that prevent vessels from invading the cornea and vitreous. Here, an inhibitor responsible for the avascularity of these ocular compartments is identified as pigment epithelium–derived factor (PEDF), a protein previously shown to have neurotrophic activity. The amount of inhibitory PEDF produced by retinal cells...