6.10 Retinal Vessel Changes (include hypertension)
The retinal vasculature undergoes numerous structural and functional changes in diabetic retinopathy as a result of processes discussed in previous submodules. The presence of high levels of AGEs induced by hyperglycemia may lead to loss of retinal vascular pericytes, formation of microaneurysms, and damage to the vascular endothelium. Tight junctions between endothelial cells loosen when exposed to elevated levels of glucose, leading to breakdown of the blood-retina barrier (BRB). Activation of PKC in retinal vascular cells leads to pericyte apoptosis, basement membrane thickening, and increases in retinal blood flow and permeability of retinal vessels.