ABSTRACT
In diabetic capillaries:
structural changes lead to both occlusion of and leakage from capillaries
basement membranes become homogeneously thickened
endothelial cell damage and proliferation result in intimal fibrosis and vessel narrowing
this is compounded by changes in red blood cells which cause defective oxygen transport and an increase in the stickiness and aggregation of platelets
despite being thickened the basement membranes of diabetic subjects are abnormally leaky, probably due to loss of pericytes, and there is increased passive transudation of plasma proteins into the surrounding tissue
it is thought that this leakage is due to loss of pericytes which are normally involved in the maintenance of endothelial barrier function
normally there is about one pericyte per endothelial cell but this ratio falls in diabetes
the protein transudate triggers a fibrous and vascular response
proteinuria is the first indication of diabetic kidney disease
changes in basement membrane structure are thought to be responsible for the peripheral neuropathy, nephropathy and retinopathy of diabetes.
