Serum levels of placental growth factor reflect the severity of retinopathy of prematurity

Abstract

Retinopathy of prematurity (ROP) is a neovascular disorder of the immature retina and a leading cause of preventable blindness worldwide.1 A two-phase hypothesis for ROP pathogenesis has been suggested.1 Phase one is vaso-obliteration, where physiological vascularity is compromised and retinal vascular development is delayed by a hyperoxic environment. This induces vasoconstriction, with decreased levels of vascular endothelial growth factor (VEGF) and insulin growth factor-1. Phase two is vasoproliferation, where the avascular retina becomes hypoxic and releases angiogenic factors. This can lead to increased angiogenesis, with abnormal proliferation of the retinal vessels into the vitreous culminating in a retinal detachment.1 Placental growth factor (PGF) is a member of the VEGF family. Its precise contribution to ocular angiogenesis is not understood,2 but it may be important in ROP.