Significant association between the endothelial lipase gene 584C/T polymorphism and coronary artery disease risk

Endothelial lipase variant T111I does not alter inhibition by angiopoietin-like proteins

High levels of HDL-C are correlated with a decreased risk of cardiovascular disease. HDL-C levels are modulated in part by the secreted phospholipase, endothelial lipase (EL), which hydrolyzes the phospholipids of HDL and decreases circulating HDL-C concentrations. A 584C/T polymorphism in LIPG, the gene which encodes EL, was first identified in individuals with increased HDL levels. This polymorphism results in a T111I point mutation the EL protein. The association between this variant, HDL levels, and the risk of coronary artery disease (CAD) in humans has been extensively studied, but the findings have been inconsistent. In this study, we took a biochemical approach, investigating how the T111I variant affected EL activity, structure, and stability. Moreover, we tested whether the T111I variant altered the inhibition of phospholipase activity by angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4), two known EL inhibitors. We found that neither the stability nor enzymatic activity of EL was altered by the T111I variant. Moreover, we found no difference between wild-type and T111I EL in their ability to be inhibited by ANGPTL proteins. These data suggest that any effect this variant may have on HDL-C levels or cardiovascular disease are not mediated through alterations in these functions.

Endothelial Lipase Variant, T111I, Does Not Alter Inhibition by Angiopoietin-like Proteins

High levels of HDL-C are correlated with a decreased risk of cardiovascular disease. HDL-C levels are modulated in part by the secreted phospholipase, endothelial lipase (EL), which hydrolyzes the phospholipids of HDL and decreases circulating HDL-C concentrations. A 584C/T polymorphism in LIPG, the gene which encodes EL, was first identified in individuals with increased HDL levels. This polymorphism results in a T111I point mutation the EL protein. The association between this variant, HDL levels, and the risk of coronary artery disease (CAD) in humans has been extensively studied, but the findings have been inconsistent. In this study, we took a biochemical approach, investigating how the T111I variant affected EL activity, structure, and stability. Moreover, we tested whether the T111I variant altered the inhibition of phospholipase activity by angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4), two known EL inhibitors. We found that neither the stability nor enzymatic activity of EL was altered by the T111I variant. Moreover, we found no difference between wild-type and T111I EL in their ability to be inhibited by ANGPTL proteins. These data suggest that any effect this variant may have on HDL-C levels or cardiovascular disease are not mediated through alterations in these functions.

Apolipoprotein E Gene Polymorphism and Coronary Artery Disease Risk Among Patients in Northwest China

Purpose

The association between apolipoprotein E (ApoE) gene polymorphisms and the risk of coronary artery disease (CAD) among different populations has been assessed in numerous previous studies, but the results remain inconclusive. The present study aimed to determine the role of ApoE genotypes in CAD risk and the interrelationships between lipid profiles and ApoE alleles and genotypes among the population of northwest China.

Patients and Methods

This study was performed on 308 patients with CAD and 308 control participants. ApoE gene polymorphism was analysed using the polymerase chain reaction and hybridization.

Results

The findings indicated that the frequencies of ε3/ε4 genotype and ε4 allele frequency were significantly higher in patients with CAD than in the control participants. ε2 carriers had significantly lower total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) levels than did ε3 or ε4 carriers among the control participants. However, our study found no significant differences in plasma lipoprotein levels between ɛ2, ɛ3 and ɛ4 carriers in patients with CAD. Moreover, ε4 carriers had significantly higher ApoB, ApoB/ApoA-I levels and significantly lower ApoE levels in both patients with CAD and control participants. ε4 allele presence was associated with a nearly two-fold higher CAD risk. After adjusting for other established risk factors, ε4 allele was an independent risk factor for CAD. After stratified by age (≤ 60 years and >60 years), ε4 allele was indicated to increase the CAD risk 3.3-fold in elderly patients with CAD, but not in young patients with CAD. After stratified by sex, ε4 allele was not a risk factor in females and males patients with CAD.

Conclusion

This study provides evidence that the ε4 allele, drinking, smoking, hypertension, and TG and ApoE levels are independent risk factor for CAD among patients in northwest China.

Roles of endothelial lipase gene related single nucleotide polymorphisms in patients with coronary artery disease

The current work focused on evaluating the roles of endothelial lipase gene (LIPG) related single nucleotide polymorphisms (SNPs) in patients with coronary artery disease (CAD). This study involved 1,883 subjects with 959 CAD patients and 924 healthy controls. Data were harvested to assess the association of LIPG related SNPs including rs3744841, rs3744843, rs3813082 and rs2000813 with the risk of CAD. The CC + AC genotype in rs3813082 played a protective role for CAD [odds ratio (OR) = 0.709, P = 0.039]. Differences existed in apolipoprotein-A1 (Apo-A1) and high-density lipoprotein-cholesterol (HDL-C) levels in rs3744843 variant between control and CAD groups. The rs3744841 variant increased the levels of total cholesterol (TC), HDL-C, low-density lipoprotein cholesterol (LDL-C), Apo-A1 and Lipoprotein a (LPa) in the CAD group and TC, LDL-C, HDL-C, Apo-B, Apo-A1 in the control group. The triglyceride (TG) level was lower in rs2000813 variant in the CAD group and elevated in the control group. The rs2000813 variant decreased the number of vascular stenosis while rs3744843 and rs3744841 variants increased the number of vascular stenosis in CAD patients. This study explored the roles of LIPG related SNPs in CAD, showing that CC + AC genotype in rs3813082 was a protective factor for CAD. The rs3744843, rs3744841 and rs2000813 variants were associated with the levels of lipid parameters in CAD patients. The rs3744843, rs3744841 and rs2000813 variants influenced the number of vascular stenosis in CAD patients. The results of our study might be a promising reference for preventing CAD.