Endothelial survival factors and spatial completion, but not pericyte coverage of retinal capillaries determine vessel plasticity

SPECIFIC AIMSSince pericyte coverage determines endothelial survival and pericyte loss is a hallmark of early diabetic retinopathy, we determined 1) the susceptibility of the developing retina to vasoregression and consecutive neovascular response in the mouse model of retinopathy of prematurity in relation to quantitative pericyte coverage of retinal capillaries, and 2) the spatial and temporal expression of ligand receptor systems involved in endothelial survival and pericyte recruitment.PRINCIPAL FINDINGS1. Evolution of pericyte recruitment in the developing mouse retinaAssessing the dynamics of pericyte recruitment in the developing mouse retina, the largest increment of pericytes was found between postnatal day 7 and 8, due to the formation of the deep capillary layers of the retina. All developing capillaries from both layers were invested by pericytes, as demonstrated by immunohistochemistry of whole mount preparations and electron microscopy.2. The development of the deep capillary layer reduces t...