Involvement of RPE cells, Müller cells in the production of MCP-1 in the retinal inflammation, vascular permeability, and neovascularization following hyperglycemia and diabetes in DR patients. In addition, MCP-1 is the main factor in the recruitment of monocytes and macrophages into the retina, and these type of cells are responsible for ROS production and inflammation. ROS: reactive oxygen species; MCP-1: monocyte chemotactic protein-1; RPE cell: retinal pigment epithelium cell