Association of cyclooxygenase-2 gene -765G/C polymorphism with diabetic nephropathy

Abstract

Objective To determine the possible effect of cyclooxygenase-2 (COX-2) -765G/C polymorphism on the risk of diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM) in Kunming. Methods A total of 252 T2DM patients from the First Affiliated Hospital of Kunming Medical University between January and December 2008 were assigned to the free-DN group (n=100), microalbuminuria DN group (n=78) and macroalbuminuria DN group (n=74) according to 24-hour urinary albumin excretion ratio(24-h UAER) or spot urinary albumin/creatinine (UACR) ratio. The polymorphism of COX-2 gene -765G/C was detected by PCR-RFLP. The genotypes and allele frequency distributions were compared by using χ2 test. The related characteristics of investigated objects were compared by analysis of variance. Logistic regression analysis was performed to calculate correlated markers of DN risk. Results In T2DM patients, -765GG genotype was significantly different between microalbuminuria DN﹢macroalbuminuria DN group and free-DN group (0.901 vs 0.810; χ2=4.309, P<0.05). In DN patients, the levels of fasting plasma glucose (FPG) and 2-hour plasma glucose (2-h PG) of those with -765GG genotype were higher than those without ((7.9±4.0) vs (5.9±1.7) mmol/L, (12±5) vs (9±4) mmol/L, respectively; t values were 0.001 and 0.020, both P<0.05). Logistic regression analysis indicated that -765GG genotype (odds ratio (OR)=3.25; 95%confidence interval (CI): 1.336 to 7.901) was risk factor of DN. Conclusion The COX-2 gene promoter -765GG may be associated with DN in Kunming Han individuals with T2DM. Key words: Diabetes mellitus, type 2; Diabetic nephropathy; Genes; Cyclooxygenase-2