Serum PON-1 Activity but not Q192R Polymorphism is Related to the Extent of Atherosclerosis

Aim: Paraoxonase-1 (PON1) is an antioxidant enzyme located in high density lipoprotein (HDL). PON1 was defined as a protective factor against atherosclerosis. The aim of this study was to investigate the possible relationship between serum paraoxonase (PONase), homocysteine thiolactonase (HTase) activities and PON1 Q192R polymorphism, and the extent and severity of atherosclerosis. Methods: Blood specimens were collected from 142 individuals who had no coronary artery lesions angiographically (control group) and 128 individuals who had angiographically documented coronary artery disease of several degrees (patient group). The extent and severity of arterial lesions were evaluated by the Gensini scoring system. PONase and HTase activities were measured in serum using a spectrophotometric method. PON1 Q192R polymorphism was evaluated using PCR-RFLP after DNA isolation from blood. Results: Serum PONase and HTase activities were significantly lower in the patient group than in healthy controls (135.7 +/- 56.0 U/mL vs 153.8 +/- 62.0 U/mL, p < 0.05; 36.0 +/- 6.1 U/mL vs 43.0 +/- 4.04 U/mL, p < 0.01; respectively). In the patient group, there was a negative correlation between PONase, HTase activities and the Gensini score (r = -0.168, p = 0.039; r = -0.164, p = 0.006, respectively). In both groups, there was no significant difference in the distribution of PON1 Q192R polymorphism. In the patient group, the distribution of Gensini scores according to genotypes was not significant. Conclusion: It has been concluded that serum PONase and HTase activities might be a more relevant marker than PON1 genotype in evaluating the extent and severity of atherosclerosis.