Relationship between pericyte and endothelial cell in retinal neovascularization: a histological and immunofluorescent study of retinal angiogenesis

Abstract

Purpose: To evaluate the relationship between pericyte and endothelial cell in retinal neovascularization by histological and immunofluorescent study. Methods: Oxygen induced retinopathy (OIR) model was induced using C57BL/6J mice. The cross sections of enucleated eyes were processed with hematoxylin & eosin. Immunofluorescent staining of pericytes, endothelial cells, and N-cadherin was performed. Microfluidic devices were created and human retinal microvascular endothelial cells, human brain microvascular endothelial cells or human umbirical vein endothelial cells and human placenta pericyte were mixed and co-cultured. Results: Unlike the tree-layered vascular plexus found in normal mouse retinal angiogenesis, distinguishing neovascular tuft extending into the vitreous is identified in the OIR model. Neovascular tufts and three-layered vascular plexus were both covered with pericyte in the OIR model. In this pathologic vascularization, N-cad, known to be crucial in intercellular contact was also present. Further evaluation using microfluidic in vitro model, successfully developed microvascular network of endothelial cell covered by pericyte, mimicking normal retinal angiogenesis within 6 days. Conclusions: Not only normal vasculature, but also pathologic neovascularization show pericytes covering endothelial cells. Factors involved in endothelial cell-pericyte interaction can be evaluated as an attractive novel treatment target. These future studies can be performed with microfluidics system, which can shorten the time and provide three-dimensional structural evaluation.