Genetic Polymorphisms of Antioxidant and Antiglycation Enzymes and Diabetic Complications. How Much Can we Learn from the Genes?
OBJECTIVES Methylglyoxal is a major precursor in the formation of advanced glycation endproducts (AGEs), which are known to contribute to vascular complications such as hypertension and arterial stiffness. Methylglyoxal can be detoxified by glyoxalase 1 (GLO1). Because genetic variation in the GLO1 gene may alter the expression and/or the activity of GLO1, we investigated whether single nucleotide polymorphisms (SNPs) in the GLO1 gene are associated with vascular complications. METHODS The study entailed cross-sectional data analyses of the Cohort study of Diabetes and Atherosclerosis Maastricht (CoDAM) study and the Hoorn study, comprising a total of 1289 participants, aged 64.5 +/- 8.58 years, of whom 43.5% had normal glucose metabolism, 23.2% had impaired glucose metabolism and 33.3% had type 2 diabetes mellitus. Nine tag SNPs that cover the common GLO1 gene variation were genotyped. Levels of blood pressure and markers of atherosclerosis, arterial stiffness, renal function and AGEs were compared across genotypes. RESULTS All genotyped SNPs were in Hardy-Weinberg equilibrium. Prevalence of hypertension and markers of atherosclerosis, arterial stiffness, renal function and AGEs did not differ across genotypes of the nine SNPs. In additive models, SNP18 (rs2736654) was associated with pulse pressure [-1.20 mmHg (95% confidence interval: -2.26;-0.14)] and SNP40 (rs10484854) was associated with systolic blood pressure [-1.77 mmHg (-3.40;-0.14)]. CONCLUSION Polymorphisms in the GLO1 gene are not associated with the prevalence of hypertension, markers of atherosclerosis, renal function and AGEs and are weakly associated with pulse pressure and systolic blood pressure (possibly due to chance) in two Dutch cohorts of patients with normal glucose metabolism, impaired glucose metabolism and type 2 diabetes mellitus.