Abnormal microvasculature in diabetic neuropathy.

Microvascular abnormalities are prominent in the retina and kidney in diabetic subjects with the specific complications of the disease. It would not therefore be surprising to find similar changes in nerve, the other tissue prominently damaged in diabetes. A variety of biochemical abnormalities have been postulated as a cause of nerve damage but so far none has been reversed with any benefit to patients. It is now very clear that major structural and functional changes in the microvasculature occur in diabetic neuropathy and are probably involved in resulting nerve damage. Endothelial thickening of the endothelial basement membrane occurs, as does luminal occlusion caused by endothelial cell proliferation; human sural nerve is hypoxic; sural nerve epineurial arterioles are attenuated and involved in arteriovenous shunting associated with gross distension and tortuosity of veins; flow of fluorescein is impaired in neuropathic nerves and nerve conduction increment on exercise is impaired in neuropathy. Therapeutic intervention should now be directed at these gross abnormalities.