Complex Contributions of Methylglyoxal to Pain, Axon Degeneration, and Diabetic Peripheral Neuropathy.

Methylglyoxal is a highly reactive by-product of glycolysis that is elevated in diabetes and contributes to the development of diabetic peripheral neuropathy (DPN). DPN is characterized by nerve degeneration, typically manifesting in patients' extremities. This leads to patients experiencing numbness, burning, and pain. It has been established that elevated methylglyoxal levels lead to nociception, but the broader cellular effects of methylglyoxal on neurons in the dorsal root ganglia (DRG) remain poorly understood. This review provides mechanistic insight regarding methylglyoxal's impact on various cell types and disease contexts. Five main mechanisms were identified: protein glycation, proteostasis change, oxidative stress, metabolic changes, and increased inflammation. These mechanisms are thoroughly interconnected, contributing to cellular dysfunction associated with DPN. We propose that methylglyoxal functions as a central mediator in cellular stress, linking hyperglycemia and elevated glycolysis to neuronal dysfunction in DPN. There is extensive evidence that these mechanisms are methylglyoxal-driven in other cell types and diseases, but a gap in the field remains in determining whether and how they occur in DRG neurons. This is particularly important, as DPN is a frequent comorbidity in diabetes and metabolic diseases and greatly affects patients' quality of life. Understanding the effect of methylglyoxal on DRG in relation to these mechanisms will provide novel insights into the development of DPN and lead to new therapeutic targets.