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

Considering the importance of serum paraoxonase (PON1) in preventing from production of oxidized low-density lipoprotein (LDL), and consequently, its role in prohibiting from development of atherosclerosis, we investigated paraoxonase and arylesterase activities of PON1 in patients with coronary artery disease (CAD) and with different coronary stenosis. In the present study, 120 patients with CAD were examined and their stenosis documented by coronary angiography. Then, the patients were divided into two groups: 60 patients with less than 50% of stenosis and 60 patients with more than 70% of stenosis. Paraoxonase and arylesterase activity was measured with substrates of paraoxon and phenylacetate, respectively. The effects of eight drugs, which are prescribed in cardiovascular diseases, were assayed on paraoxonase activity. There were no significant differences in LDL-C, total cholesterol and triglyceride levels between two groups, but HDL levels in patients with >70% of stenosis were significantly decreased as compared with those of patients who had <50% of stenosis (P<0.03). Both paraoxonase and arylesterase activity in patients with >70% of stenosis were significantly lower (P<0.05) than patients with<50% of stenosis. 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 activities and HDL levels decrease with progression of atheroma. Therefore, the study might support the important role of HDL-bound PON1 in preventing from formation of ox-LDL and its anti-atherogenic activity.