Apolipoprotein E Polymorphism, Paraoxonase-1 Activity and Coronary Artery Disease: Is There a Link

Objective: The association of ApoE allele frequencies with coronary artery disease (CAD) remains unknown in developing countries. Paraoxonase 1 (PON1) is an enzyme that is associated with high density lipoprotein (HDL) and hydrolyzes oxidized lipids in oxidized low density lipoprotein (LDL) and thus protects against the development of atherosclerosis. In this study the association of apoE polymorphism and PON1 with premature CAD was determined. Methodology: The frequency of apo E alleles and the activity of the PON1 among 162 patients with early and late onset CAD was examined. Results: The mean age in the early and late-onset groups were 44.9 ± 4.9 and 71.7±2.5 years respectively. Patients with early-onset CAD had significantly lower serum levels of HDL-C and higher LDL-C/HDL-C ratio than the late-onset group. There was no difference in serum levels of triglyceride, total cholesterol and LDL-C between the two groups. The e2 allele was significantly higher in the late-onset group. 35.0% of early-onset and 17.5% of late-onset group had low level of PON1. 86% of the early-onset CAD and all of the late-onset CAD patients with e3/ e4 genotype, had low or moderate level of PON1 activity. Conclusion: We found a positive association between PON1 activity, HDL level and the onset of CAD. Our study suggests that there are modest associations between CAD and apo E alleles and that the lower activity of PON1 in the presence of lower apo E level may increase the susceptibility to early-onset CAD.