"Vascular and neural diseases are closely related and intertwined. Blood vessels depend on normal nerve function, and nerves depend on adequate blood flow. The first pathological change in the microvasculature is vasoconstriction. As the disease progresses, neuronal dysfunction correlates closely with the development of vascular abnormalities, such as capillary basement membrane thickening and endothelial hyperplasia, which contribute to diminished oxygen tension and hypoxia."
http://en.wikipedia.org/wiki/Diabetic_neuropathy
Sympathectomy results in vascular abnormalities, loss of vasoconstriction, capillary basement thickening and endothelial hyperplasia...
