Relationship of methylglyoxal-adduct biogenesis to LDL and triglyceride levels in diabetics

AimsProtein glycation leading to advanced glycation-endproducts (AGE) is enhanced in diabetes by increased blood glucose and collateral endogenous production of reactive α-dicarbonyls. Among AGE precursors, methylglyoxal (MG) is considered as one of the key intermediates. We hypothesized it to be a common product of both carbonyl and oxidative stress, and investigated its biogenesis in relation to glycemic and lipid status in diabetic patients.MethodsSerum and urine MG-adducts were measured by competitive immunofluorometric assay in 83 diabetic and 20 healthy subjects.Key findingsA significant association of MG-adducts serum level with LDL (r = 0.31;p = 0.003) was observed. A correlation between LDL-c, HDL-C and PPG as independent variables and serum MG-adducts as a dependent variable was found (p < 0.014) using multiple stepwise regression, whereas urine albumin/creatinine ratio was independently associated with urine MG-adducts. LDL cut-off > 3.0 mmol/l discriminated patients with higher serum MG-adducts (p = 0.0052), although there was no between-subgroup difference in glycemic control. Patients on statin therapy had a lower MG-adduct level. The positive relationship between LDL-c and MG-adducts (r = 0.38;p = 0.042) was noted in patients free of statin treatment, whereas an inverse tendency was found in the statin-treated subgroup.SignificanceSignificant relationship between LDL and MG-adduct production, as well as tight correlation between triglycerides and urinary MG-adduct excretion suggest that the lipoxidation and glyceraldehyde-3-phosphate route, along with the glycolytic pathway, might be an important source of MG generation. The glycotoxin methylglyoxal seems to be a common factor linking hyperglycemia and intensive lipolysis, two dominant metabolic changes in diabetes.