Study of the relationship between endothelial lipase gene polymorphism and serum levels of HDL-C, Apo A-I and severity of stenosis in non-diabetic coronary artery disease patients

Background: The endothelial lipase (EL) gene is one of the most important genes in the metabolism of high density lipoprotein cholesterol (HDL-C), and then it may be involved in the pathogenesis of coronary artery disease (CAD). The present study aimed to reveal the potential relationship between the EL 584C/T gene polymorphism and CAD severity, serum apolipoprotein A-I (Apo A-I), Apo B, and HDL-C levels in non-diabetic CAD patients. Methods: 248 subjects including 89 non-CAD controls and 159 non-diabetic CAD patients were included in the study. Blood sample was collected and used for genomic DNA extraction. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was carried out for genotyping of EL 584C/T. Serum levels of Apo AI and Apo B were determined using the immunoturbidometric assay. The severity of coronary stenosis was determined using the Gensini score (GS). Results: The frequency of CC genotype was 52.9% and the frequency of CT and TT genotypes was 47.1% in non CAD group. These frequencies were 59.6% and 40.4% in CAD group, respectively. There was no significant difference in the frequency of 584C/T polymorphism between CAD and non-CAD group. Moreover, the genotype and allele frequencies of the 584C/T polymorphism were not statistically different in subjects with different degrees of coronary stenosis. The serum level of Apo A-I was markedly increased in non-CAD group rather than CAD group. Those subjects with TT and CT genotypes had significantly higher levels of Apo A-I compared to those with CC genotype. Conclusion: Our results showed that 584C/T polymorphism of the EL gene was not associated with the risk of CAD. However, subjects with TT and CT genotypes showed higher Apo A-I levels compared to subjects with CC genotype suggesting a possible role of these genotype in the pathogenesis of CAD.