Enzyme Activity and Genetic Polymorphisms of Paraoxonase 1 in Patients With Type 2 Diabetes Mellitus: A Case-Control Study

Paraoxonase-1 (PON1) plays a role in the prevention of lipid peroxidation and has been linked to type 2 diabetes mellitus, which is characterised by elevated oxidative stress. In this case-control study, 102 patients with T2DM and 102 healthy controls aged 30 to 60 were included. Anthropometric and body composition measurements of individuals were taken. Total antioxidant status (TAS), total oxidant status (TOS), PON1 activity, and metabolic parameters were analyzed in serum samples of all participants. These samples were genotyped by TaqMan. Dietary antioxidant capacity (DTAC) of individuals was assessed using 3-day food records. No statistically significant difference was observed between groups in the alleles and the genotype frequencies of SNPs. PON1 activity was significantly higher in controls compared to patients with T2DM. Furthermore, RR and LL genotypes were significantly associated with higher PON1 activity. In T2DM patients, HbA1c, fasting blood sugar (FBG), and LDL-cholesterol (LDL-c) were more elevated in all genotypes of the Q192R gene; triglyceride (TG) was higher in QQ and QR genotypes of the gene; TAS was higher in the RR genotype of the gene; and DTAC was lower in the QQ genotype of the gene compared to their respective controls. In controls, LDL-c and TG were lower in all genotypes of the L55M gene; HbA1c and FBG were lower in the LL and LM genotypes of the gene; total body fat was more down in MM genotype, but total body water, fat-free mass, and MET score were higher in MM genotype of the gene compared to their respective controls. Multiple linear regression analyses showed that several factors associated with the activity of PON1 were the PON1 genotypes, HDL-c, TAS, and TOS. Our study supports that the PON1 polymorphisms are associated with PON1 activity, glucose, and lipid metabolism parameters in patients with T2DM.