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Diabetes stands as the predominant cause of peripheral neuropathy, and diabetic neuropathy (DN) is an early-onset and most frequent complication of diabetes. Distal symmetric polyneuropathy is the major form of DN; however, various patterns of nerve injury can manifest. Growing evidence suggests that hyperglycemia-related metabolic disorders in neurons, Schwann cells, and vascular endothelial cells play a major role in the development and progression of DN; however, its pathogenesis and development of disease-modifying therapies warrant further investigation. Herein, recent studies regarding the possible pathogenic factors of DN (polyol and other collateral glycolysis pathways, glycation, oxidative stress, Rho/Rho kinase signaling pathways, etc.) and therapeutic strategies targeting these factors are introduced.

Diagnostic criteria of diabetic neuropathy that can be easily used at bedsides and have international consensus have not been established. The most important therapeutic strategy is to maintain strict glycemic control. In addition, treatment with an aldose reductase inhibitor that is innovated from the viewpoint of the pathogenesis of diabetic neuropathy would be useful for preventing the progression of diabetic neuropathy. For painful diabetic neuropathy, pregabalin and duloxetine effectively relieve the pain, and contribute to the improvement of the quality of life.

Drastic increase in a population of diabetic patients urges to establish effective treatment or management of peripheral neuropathy, the most common complication of diabetes. Recent studies emphasize the occurrence of peripheral neuropathy in patients with impaired glucose tolerance, which condition is now shown to augment polyol pathway as well as non-enzymatic protein glycation in the peripheral nerve, exerted by postprandial hyperglycemia. Such metabolic cascades in turn result in tissue-specific alterations of cellular signaling, represented by decreased protein kinase C (PKC) activity and Na, K-ATPase activity in the peripheral nerve and contrariwise increased PKC activity in microvessels. The decrease in nerve PKC activity was demonstrated to associate with reduced membrane alpha-isoform expression and the increase in vessel PKC activity was due to membrane beta-isoform expression, respectively. Dual mechanisms of nerve and vascular alterations in addition to multiple metabolic factors may operate in the development of diabetic neuropathy in a complicated manner. Consequently, inhibition of hyperglycemia as well as specific intervention of single molecules related to altered cellular signaling is the essential approach for the primary prevention of diabetic neuropathy.