Paraoxonase and Arylesterase activities of human serum paraoxonase in coronary artery disease

Introduction: Considering the importance of serum paraoxonase (PON1) in preventing fromproduction of oxidized low-density lipoprotein (LDL), and consequently, its role in prohibiting fromdevelopment of atherosclerosis, we investigated paraoxonase and arylesterase activities of PON1 inpatients with coronary artery disease (CAD) and with different coronary stenosis.Materials and Methods: In the present study, 120 patients with CAD were examined and theirstenosis documented by coronary angiography. Then, the patients were divided into two groups: 60patients with less than 50% of stenosis and 60 patients with more than 70% of stenosis. Paraoxonaseand arylesterase activity was measured with substrates of paraoxon and phenylacetate, respectively.The effects of eight drugs, which are prescribed in cardiovascular diseases, were assayed onparaoxonase activity.Results: There were no significant differences in LDL-C, total cholesterol and triglyceride levelsbetween two groups, but HDL levels in patients with >70% of stenosis were significantly decreased ascompared with those of patients who had <50% of stenosis (P<0.03). Both paraoxonase andarylesterase activity in patients with >70% of stenosis were significantly lower (P<0.05) than patientswith<50% of stenosis.Conclusion: Paraoxonase and arylesterase activities of PON1 and HDL levels in patients with>70% of stenosis were lower than patients with <50% of stenosis. In other words, the PON1 activitiesand HDL levels decrease with progression of atheroma. Therefore, the study might support theimportant role of HDL-bound PON1 in preventing from formation of ox-LDL and its anti-atherogenicactivity