Determination of serum paraoxonase phenotype distribution by double-substrate method in patients with coronary artery disease

ABSTRACT

Considering the high incidence of patients with coronary artery disease [CAD] in the Iranian population and a preventive role of serum paraoxonase [PON1] in development of CAD, the present study was designed to determine the distribution of PON1 phenotypes in patients with CAD. A total of 61 patients with coronary stenosis of <50% and 63 patients with coronary stenosis of >70% were included in this study. Paraoxonase and arylesterase activities were measured using paraoxon and phenylacetate as substrate, respectively. Phenotyping of the PON1 Q192R polymorphism was determined by calculating the ratio of salt-stimulated paraoxonase activity to arylesterase activity [double-substrate method]. Patients with stenosis of <50% were separated into three distinct phenotypes at ratios of 2.14 and 5.99 and the population with stenosis of >70% at ratios of 2.42 and 5.91. In patients with stenosis of <50%, PON1 phenotype frequencies were 41% [Q phenotype], 46% [QR phenotype] and 13% [R phenotype]. Frequencies of Q, QR and R phenotypes in patients with stenosis of >70% were 48%, 41% and 11%, respectively. Based on this study and other studies conducted in Iran, it can be concluded that in the Iranian population there is no statistically difference in phenotype distribution of PON1 between patients with CAD [with severe stenosis or mild stenosis] and healthy individuals