Question

What physiological mechanisms contribute to peripheral neuropathy in type 2 diabetes?

Answer 1

Ans) Diabetic neuropathy is a peripheral neuropathy in which sensory and motor nerves are damaged or destroyed as a result of ischemic microvascular disease and nonenzymatic glycosylation of neuronal component.

- Diabetic neuropathy occurs when there is an imbalance between nerve fiber damage and repair.

- The nerve damaging process preferentially affects autonomic and distal sensory fibers, leading to the progressive loss of sensation.

- Besides metabolic factors listed above, ischemic factors and inflammation also contribute to the development of diabetic neuropathies.

• Metabolic factors seem to prevail in length-dependent diabetic polyneuropathy, whereas inflammation superimposed on ischemic nerve lesions is found in severe forms of focal neuropathies. The thickening and hyalinization of the walls of small blood vessels due to the reduplication of the basal lamina around endothelial cells suggests a role for nerve ischemia in diabetic neuropathy.

- There is also a reduction in endoneurial oxygen tension in the sural nerves of diabetic patients with advanced polyneuropathy.

- Possible mechanisms for neuropathy development include oxidative stress, nonenzymatic glycation, the polyol pathway, the hexosamine pathway, protein kinase C pathway, poly (ADP-ribose) polymerase and the reduction of neurotrophic factors.