Retinopathy of prematurity (ROP) is a blinding disease, initiated by delayed retinal vascular growth after premature birth. There are both oxygen-regulated and non-oxygen-regulated factors, which contribute to both normal vascular development and retinal neovascularization. One important oxygen-regulated factor, critical to both phases of ROP, is vascular endothelial growth factor (VEGF). A critical non oxygen-regulated growth factor is insulin-like growth factor (IGF-1). In knockout mice, lack of IGF-1 prevents normal retinal vascular growth, despite the presence of VEGF, important to vessel development. In vitro, low IGF-1 prevents vascular endothelial growth factor-induced activation of Akt, a kinase critical for vascular endothelial cell survival. Premature infants who develop ROP have lower levels of serum IGF-1 than age-matched infants without disease.
Conclusion: IGF-1 is critical to normal vascular development. Low IGF-1 predicts ROP and restoration of IGF-1 to normal levels may prevent ROP.