Potential contribution of mobilized circulating endothelial progenitor cells to development of retinal neovascularization in preterm infants with ROP.

ABSTRACT

PURPOSE: To investigate the role of endothelial progenitor cells in the pathogenesis of abnormal blood vessel formation in preterm infants with retinopathy of prematurity. MATERIAL AND METHODS: A total of 29 preterm infants with proliferative stage of retinopathy of prematurity and neovascularizatio (grade 3 or higher) were involved in this study. The CD133+/CD34+/CD144+ EPC count in peripheral blood was measured b flow cytometry. Plasma levels of stromal derived factor-1 (SDF-1), vascular endothelial growth factor, and insulin-like growth factor-1 (IGF-1) were quantified by enzyme-linked immunosorbent assay (ELISA). All cellular and biochemical measurements were performed twice in the same neonate i) initially, during the proliferative phase of ROP, and ii) subsequently, during the remission after a successful retinal photocoagulation and regression of pathological blood vessels. RESULTS: The endothelial progenitor cells count significantly decreased during the remission phase, compared to the proliferative phase of retinopathy of prematurity in the same neonates. The SDF-1 plasma level was found to be markedly lower during the remission stage and positively correlated with the endothelial progenitor cell count in peripheral blood. CONCLUSIONS: The endothelial progenitor cell count in peripheral blood of preterm infants significantly decreased with the regression of abnormal vasculature in the neonate retina. This may indicate that pathological blood vessel formation during the proliferative phase of retinopathy of prematurity results not only from local endothelial proliferation but also from the systemic endothelial progenitor cell mobilization.