PathogenesisIt is the vascular changes in diabetes that leads to the complications. High blood glucose causes endothelial changes causing increased production of reactive oxygen species (ROs), growth factors (VEGF, cell growth factors), toxic metabolites and cytokines. The production of these substances promotes atherosclerosis, arteriosclerosis causing ischaemic changes. The metabolic toxins together with the ischaemic changes lead to the microvascular and macrovascular changes seen in diabetes.