INS and Hyperglycemia: [11] There are molecular biological explanations for the relationships between hyperglycemia and DR. First, the capillary endothelial cells in the retina are insulin-insensitive and so cannot regulate glucose well. [12], [13] Hyperglycemia hastens the production of reactive oxygen species (ROS), which leads to cell death. [14] Furthermore, advanced glycation end products may induce VEGF, [15] which promotes neovascularization. Finally, the capillary basement membrane thickens in response to hyperglycemia and causes tissue hypoxia, which also induces new vessel growth [16].