Association between the adiponectin promoter rs266729 gene variant and oxidative stress in patients with diabetes mellitus

Low levels of adiponectin are associated with type 2 diabetes and coronary heart disease (CHD). Recent evidence also suggests that low levels of adiponectin are associated with increased oxidative stress. Our aim was to examine the association between the rs266729 promoter gene variant (-11377C > G) and plasma markers of oxidative stress in diabetes subjects. Seven hundred and sixty-seven Caucasian subjects with diabetes were successfully genotyped (CC/CG/GG). Genotype data were analysed in relation to plasma total antioxidant status (TAOS) and Oxidized-LDL (Ox-LDL). Plasma adiponectin measurements were available in 206 samples. There was a significant association between genotype and plasma TAOS (CC: 42.1 +/- 13.4% vs. CG: 42.0 +/- 12.0% vs. GG: 47.9 +/- 12.0%, P = 0.02; for CC/CG vs. GG, P = 0.006). With respect to Ox-LDL, CC subjects had 8% higher plasma Ox-LDL compared with CG/GG [CC vs. CG vs. GG: 48.5 (36.3-60.2) U/L vs. 44.8 (35.6-54.1) U/L vs. 44.9 (41.2-49.1) U/L, for CC vs. CG/GG P = 0.03]. For plasma adiponectin, GG subjects had the highest levels [CC vs. CG vs. GG: 8.18 (5.69-15.38) mu g/mL vs. 7.12 (5.34-12.97) mu g/mL vs. 11.84 (6.98-25.25) mu g/mL, P = 0.09; for CC/CG vs. GG, P = 0.05]. This study shows an association between a promoter variant in the adiponectin gene and plasma markers of oxidative stress. In line with previous studies, this work supports an antioxidant role for adiponectin which may explain its cardioprotective effect. Further prospective study is necessary to explore the effect of this gene variant in diabetes in relation to CHD risk and oxidative stress.