Association of CETP and LIPC Gene Polymorphisms with HDL and LDL Sub-fraction Levels in a Group of Indian Subjects: A Cross-Sectional Study

Causal association between lipoproteins and risk of coronary artery disease-a systematic review and meta-analysis of Mendelian randomization studies

OBJECTIVE

To systematically evaluate the causal effect of lipoproteins to the risk of coronary artery disease (CAD) by systematic review and meta-analysis of the associated Mendelian randomization (MR) studies.

METHODS

This systematic review was registered in PROSPERO (ID CRD42023465430). Searches from the databases (e.g., PubMed, Embase, Cochrane, Web of Science) and non-database sources to collect MR studies. The search time frame was from the database inception to August 2023. After data extraction, quality evaluation was performed, and the meta-analysis with bias evaluation was carried out with RevMan software.

RESULTS

A total of 5,828,409 participants from 21 records were included. Quality and bias assessment was performed by evaluating the internal three assumptions of MR studies. Meta-analysis for the causal association between non-HDL lipoproteins and CAD showed a significantly positive association between LDL and CAD (OR 1.37, 95% CI 1.26-1.49; P < 0.001, I2 = 95%), apoB and CAD (OR 1.38, 95% CI 1.11-1.71; P = 0.003, I2 = 98%), and Lp(a) and CAD (OR 1.21, 95% CI 1.12-1.31; P < 0.001, I2 = 99%). Interestingly, although there was no statistical significance in the association between VLDL/apoA1 and CAD (both P > 0.05), the pooled non-HDL lipoproteins showed a significantly positive association with CAD (OR 1.28, 95% CI 1.22-1.34; P < 0.001, I2 = 99%). For the HDL lipoproteins, the pooled OR showed a significantly negative association with CAD (OR 0.84, 95% CI 0.72-0.98; P = 0.002, I2 = 72%). However, the protective effect of HDL on CAD diminished when analyzed together with apoA1 and/or apoB (both P > 0.05). The funnel plot did not show serious publication bias, and sensitivity analysis performed relatively well robustness of the causal association of LDL, apoB, Lp(a), and total cholesterol with CAD.

CONCLUSION

The present meta-analysis suggests an overall effect of causal association between lipoproteins and CAD. Most of the non-HDL lipoproteins (LDL, apoB, Lp(a)) promote CAD, while the protective effect of HDL in CAD still needs to be verified in the future.

Association of CETP Gene Polymorphisms and Haplotypes with Cardiovascular Risk

Cholesteryl ester transfer protein (CETP) is known to influence HDL-C levels, potentially altering the profile of HDL subfractions and consequently cardiovascular risk (CVR). This study aimed to investigate the effect of five single-nucleotide polymorphisms (SNPs; rs1532624, rs5882, rs708272, rs7499892, and rs9989419) and their haplotypes (H) in the CETP gene on 10-year CVR estimated by the Systematic Coronary Risk Evaluation (SCORE), the Framingham Risk Score for Coronary Heart Disease (FRS_CHD) and Cardiovascular Disease (FRS_CVD) algorithms. Adjusted linear and logistic regression analyses were used to investigate the association of SNPs and 10 haplotypes (H1-H10) on 368 samples from the Hungarian general and Roma populations. The T allele of rs7499892 showed a significant association with increased CVR estimated by FRS. H5, H7, and H8 showed a significant association with increased CVR based on at least one of the algorithms. The impact of H5 was due to its effect on TG and HDL-C levels, while H7 showed a significant association with FRS_CHD and H8 with FRS_CVD mediated by a mechanism affecting neither TG nor HDL-C levels. Our results suggest that polymorphisms in the CETP gene may have a significant effect on CVR and that this is not mediated exclusively by their effect on TG and HDL-C levels but also by presently unknown mechanisms.

The Effect of Haplotypes in the CETP and LIPC Genes on the Triglycerides to HDL-C Ratio and Its Components in the Roma and Hungarian General Populations

BACKGROUND

The triglycerides (TG) to high-density lipoprotein (HDL)-cholesterol (HDL-C) ratio (TG/HDL-C) is a well-known predictor for cardiovascular diseases (CVDs) with great heritability background. The cholesteryl ester transfer protein (CETP) and hepatic lipase (LIPC) gene affect TG/HDL-C ratio. This study aims to explore the association between haplotypes (H) in CETP (based on 5 single nucleotide polymorphisms (SNPs)) and LIPC (based on 6 SNPs) genes and the TG/HDL-C ratio and its components, among Roma and Hungarian general populations.

METHODS

The prevalence of haplotypes and their effect on HDL-C, TG and TG/HDL-C ratio were calculated in both populations and compared.

RESULTS

Ten haplotypes in CETP and 6 in LIPC gene were identified. Three haplotypes in CETP and 3 in LIPC have significant effect on HDL-C level, whereas two in CETP and 3 in LIPC on TG level. The H6 in CETP (β = 0.52, p = 0.015; odds ratio (OR) = 1.87, p = 0.009) and H5 in LIPC (β = 0.56, p < 0.001; OR = 1.51, p = 0.002) have a significant increasing effect on TG/HDL-C ratio and have shown higher prevalence among the Roma, as compared to Hungarian general population. The H2 in the CETP gene has a decreasing effect on the TG/HDL-C ratio (OR = 0.58, p = 0.019) and is significantly less frequent among the Roma.

CONCLUSIONS

Accumulation of harmful haplotypes in CETP and LIPC genes might have a role in the elevated TG/HDL-C ratio in the Roma population, which contributes to a higher risk in the development of cardiovascular diseases.

CETP genotype and concentrations of HDL and lipoprotein subclasses in African-American men

Aim: To assess the association between the CETP Taq1B and I405V polymorphisms with levels of lipoprotein subclasses in African-American (AA) men with and without Type 2 diabetes (T2DM). Patients & methods: AA men, over 30 years of age, with (n = 54) or without T2DM (n = 50), and not receiving lipid-lowering agents, underwent advanced lipid analysis and genotyping. Results & conclusion: In the total patient population Taq1B B2-allele carriers had significantly higher levels of large HDL subclasses (HDL-2b [p = 0.017] and HDL-L [p = 0.019]), lower levels of small-HDL subclasses (HDL-3a [p = 0.004] and HDL-3b [p = 0.031]), and lower levels of LDL subclasses (LDL-IVa [p = 0.012] and LDL-IIIb [p = 0.009]). The only significant genotype-diabetes interaction occurred with the HDL-2a subclass (p = 0.015). No statistically significant associations were seen with I405V genotype. Our observations of lower levels of small-HDL and higher levels of large-HDL suggest that a potentially important HDL subclass-CETP relationship exists.

Genetic and Non-Genetic Factor-Adjusted Association between Coffee Drinking and High-Density Lipoprotein Cholesterol in Taiwanese Adults: Stratification by Sex

Low high-density lipoprotein cholesterol (HDL-C) is a major risk factor for cardiovascular diseases (CVDs), the leading cause of global mortality. We aimed to determine the effect of coffee drinking and sex and their interaction, as well as rs1800588 and rs1800775 polymorphisms on HDL-C levels in Taiwanese adults. Data of 4262 men and 4813 women, aged 30–70 years, were retrieved from Taiwan Biobank. The interaction between sex and coffee drinking on HDL-C was significant (p = 0.0452). Coffee consumption was significantly associated with higher HDL-C levels in only women (β = 0.81679; p = 0.0246). However, rs1800588 and rs1800775 variants were significantly associated with HDL-C in both sexes. In women, β-values were 0.99080; p = 0.0059 and 3.16277; p < 0.0001 for rs1800588 CT and TT genotypes, respectively and −1.80954; p < 0.0001 and −2.81512; p < 0.0001 for rs1800775 AC and CC genotypes, respectively. In men, β-values were 1.32430; p < 0.0001 and 3.24976; p < 0.0001 for rs1800775 CT and TT genotypes, respectively and −1.96232; p < 0.0001 and −2.71536, p < 0.0001 for the AC and CC genotypes, respectively. In conclusion, coffee drinking was significantly associated with higher high-density lipoprotein (HDL) levels in women but not men after adjusting for confounders including rs1800588 (LIPC) and rs1800775 (CETP) variants.

There is an association between a genetic polymorphism in the ZNF259 gene involved in lipid metabolism and coronary artery disease

BACKGROUND

Recent genome-wide association studies (GWAS) have identified several genetic variants that influence the risk of dyslipidemia and coronary artery disease (CAD). In this study, we have examined the potential association of five SNPs variants related to lipid pathway, previously identified in GWAS studies (ZNF259 C>G, CETP I405VA/G, LPA C>T, LPLS447X and PSRC1 A>G) with CAD.

METHODS

Two hundred and ninety subjects including 194 patients with coronary artery disease and 96 controls were enrolled, followed by the analyses of anthropometric/biochemical parameters. Genotyping was carried out using Taq-Man real-time PCR based method. The association of the genetic polymorphisms with CAD was determined using univariate and multivariate analyses.

RESULTS

CAD patients had a higher (p < 0.05) fasting blood glucose (FBG), total cholesterol (TC), high sensitivity C-reactive protein (hs-CRP), low-density lipoprotein cholesterol (LDL-C) and waist circumference. Results showed that subjects with CETP rs5882 genetic variant, AA&AG genotypes, had a higher risk of developing Coronary artery disease [OR: 2.1, 95% CI (1.2-4.1), p value = 0.015]. Also subjects who carried the G allele of the ZNF259 polymorphism were at an increased the risk of developing CAD [OR 1.86, 95% CI: 1.06-3.25, p value = 0.029] and had an increased TC, LDL and TG levels (p < 0.05). Furthermore, no statistically significant association was found between genetic polymorphisms of PSRC1 A>G, LPL S447X and LPA C>T and CAD.

CONCLUSION

We identified a relationship between a genetic variant in CETP and ZNF259 gene with CAD and CAD and lipid profile, respectively. Further investigation in a larger population may help to investigate the value of emerging marker as a risk stratification marker in CAD and its risk factors.

Generalizability and applicability of results obtained from populations of European descent regarding the effect direction and size of HDL-C level-associated genetic variants to the Hungarian general and Roma populations

OBJECTIVES

Large-scale association studies that mainly involve European populations identified many genetic loci related to high-density lipoprotein cholesterol (HDL-C) levels, one of the most important indicators of the risk for cardiovascular diseases. The question with intense speculation of whether the effect estimates obtained from European populations for different HDL-C level-related SNPs are applicable to the Roma ethnicity, the largest minority group in Europe with a South Asian origin, was addressed in the present study.

DESIGN

The associations between 21 SNPs (in the genes LIPC(G), CETP, GALNT2, HMGCP, ABCA1, KCTD10 and WWOX) and HDL-C levels were examined separately in adults of the Hungarian general (N = 1542) and Roma (N = 646) populations by linear regression. Individual effects (direction and size) of single SNPs on HDL-C levels were computed and compared between the study groups and with data published in the literature.

RESULTS

Significant associations between SNPs and HDL-C levels were more frequently found in general subjects than in Roma subjects (11 SNPs in general vs. 4 SNPs in Roma). The CETP gene variants rs1532624, rs708272 and rs7499892 consistently showed significant associations with HDL-C levels across the study groups (p ˂ 0.05), indicating a possible causal variant(s) in this region. Although nominally significant differences in effect size were found for three SNPs (rs693 in gene APOB, rs9989419 in gene CETP, and rs2548861 in gene WWOX) by comparing the general and Roma populations, most of these SNPs did not have a significant effect on HDL-C levels. The β coefficients for SNPs in the Roma population were found to be identical both in direction and magnitude to the effect obtained previously in large-scale studies on European populations.

CONCLUSIONS

The effect of the vast majority of the SNPs on HDL-C levels could be replicated in the Hungarian general and Roma populations, which indicates that the effect size measurements obtained from the literature can be used for risk estimation for both populations.

Association between the Hepatic Lipase Promoter Region Polymorphism (-514 C/T) and the Presence and Severity of Premature Coronary Artery Disease

Background: Hepatic lipase (HL) plays a crucial role in lipid metabolism, but there is debate about whether HL acts in a more pro- or more anti-atherogenic fashion. We aimed to examine the relationship between the -514 C/T polymorphism within the HL gene (LIPC) and the risk of angiographically determined premature coronary artery disease (CAD). Methods: Four hundred seventy-one patients with newly diagnosed angiographically documented (≥ 50% luminal stenosis of any coronary vessel) premature CAD were compared to 503 controls (subjects with no luminal stenosis in coronary arteries). A real-time polymerase chain reaction and high-resolution melting analysis was used to distinguish between the genotypes. Results: There was no significant difference in the distribution of -514 C/T genotypes between the 2 groups in the whole population or in the men, but the examined polymorphism was found to be associated with the presence of CAD in the women (p value = 0.029). After the application of a multiple logistic regression model, the minor T allele of the LIPC gene was not found to be independently associated with the presence of CAD either in the total population (adjusted OR = 0.97, 95% CI = 0.75-1.25; p value = 0.807) or in the women (adjusted OR = 0.91, 95% CI = 0.59-1.40; p value = 0.650) and in the men (adjusted OR = 1.15, 95% CI = 0.81-1.64; p value = 0.437) separately. Conclusion: Our findings suggest that there is no relationship between the LIPC -514 C/T and the risk of premature CAD or its severity in patients undergoing coronary angiography.

Additive Antiatherogenic Effects of CETP rs708272 on Serum LDL Subfraction Levels in Patients with CHD Under Statin Therapy

Recently, subfraction analysis of serum low density lipoprotein (LDL) is considered to be a better predictor of the risk of coronary heart disease (CHD) compared to the other lipid parameters. The aim of this study was to examine the effects of the HDL-associated Taq1B (rs708272) SNP of cholesterol ester transfer protein (CETP) gene on serum LDL subfractions in patients with CHD. Serum lipid levels were measured enzymatically and LDL subfraction analysis was carried out by the Lipoprint System (Quantimetrix, CA, USA). The CETP rs708272 SNP was studied in 66 healthy controls and 79 patients with CHD receiving statin therapy by the PCR-RFLP technique. The CHD patients had elevated antiatherogenic LDL-1 subfraction (p = 0.042), decreased atherogenic IDL-C subfraction (p = 0.023), and total IDL (p = 0.030) levels compared to the healthy controls. The CETP rs708272 Taq1B minor B2 allele was associated with increased levels of antiatherogenic LDL-1 (B2: 0.40 ± 0.20 vs. B1B1: 0.25 ± 0.08, p = 0.004) and large-LDL (LDL 1-2) subfractions in the CHD group (B2 allele: 0.68 ± 0.41 vs. B1B1: 0.42 ± 0.20; p < 0.05), while it was associated with reduced levels of the large-LDL subfraction in healthy subjects (B2 allele: 0.29 ± 0.14 vs. B1B1: 0.54 ± 0.24; p = 0.017). However, there was no statistically significant association between the CETP rs708272 SNP and small dense LDL subfraction (LDL 3-7) and lipoprotein levels (p > 0.05). Our findings have indicated that the CETP rs708272 SNP together with statin therapy may show a favorable effect on antiatherogenic LDL-1 and large-LDL subfractions in CHD patients with an atherogenic effect on large-LDL subfraction in healthy subjects. Based on these results, it can be concluded that the effects of the CETP variation on LDL subfraction could change in cardiometabolic events such as CHD and statin therapy.

Cholesteryl ester transfer protein gene polymorphism (I405V) and premature coronary artery disease in an Iranian population

The effect of human cholesteryl ester transfer protein (CETP) expression on atherogenesis is still under debate. The rs5882 (I405V) polymorphism affect CETP function. We aimed to examine the relationship between the rs5882 polymorphism and the risk of angiographically determined coronary artery disease (CAD). To define premature CAD (PCAD), an age cutoff of 55 years for women and 45 years for men was used. An age- and sex-matched case-control study was conducted in 560 patients with newly diagnosed angiographically documented PCAD (≥50% luminal stenosis of any coronary vessel) and an equal number of control patients with normal coronary arteries (no luminal stenosis at coronary arteries). The severity of CAD was determined by vessel score and Gensini score. A real-time polymerase chain reaction (PCR) and high resolution melting analysis were used to distinguish between genotypes. The I405V genotype distributions were not statistically different in CAD and non-CAD groups in univariate and multivariable-adjusted logistic regression analyzes. The median and inter-quartile range for Gensini score was not significantly different among the AA (43, 24 to 73), AG (40, 20 to 66), and GG (45, 25 to 72) genotypes (p = 0.097). Furthermore, the distribution of vessel score did not statistically differ between these genotypes (p = 0.691). Our results suggest that there is no significant association between CETP I405V polymorphism and the risk of PCAD presence and severity. Larger prospective studies are needed to investigate such associations in different populations.

Functional Regression Models for Epistasis Analysis of Multiple Quantitative Traits

To date, most genetic analyses of phenotypes have focused on analyzing single traits or analyzing each phenotype independently. However, joint epistasis analysis of multiple complementary traits will increase statistical power and improve our understanding of the complicated genetic structure of the complex diseases. Despite their importance in uncovering the genetic structure of complex traits, the statistical methods for identifying epistasis in multiple phenotypes remains fundamentally unexplored. To fill this gap, we formulate a test for interaction between two genes in multiple quantitative trait analysis as a multiple functional regression (MFRG) in which the genotype functions (genetic variant profiles) are defined as a function of the genomic position of the genetic variants. We use large-scale simulations to calculate Type I error rates for testing interaction between two genes with multiple phenotypes and to compare the power with multivariate pairwise interaction analysis and single trait interaction analysis by a single variate functional regression model. To further evaluate performance, the MFRG for epistasis analysis is applied to five phenotypes of exome sequence data from the NHLBI’s Exome Sequencing Project (ESP) to detect pleiotropic epistasis. A total of 267 pairs of genes that formed a genetic interaction network showed significant evidence of epistasis influencing five traits. The results demonstrate that the joint interaction analysis of multiple phenotypes has a much higher power to detect interaction than the interaction analysis of a single trait and may open a new direction to fully uncovering the genetic structure of multiple phenotypes.

The widely used statistical methods test interaction for single phenotype. However, we often observe pleotropic genetic interaction effects. The simultaneous gene-gene (GxG) interaction analysis of multiple complementary traits will increase statistical power to detect GxG interactions. Although GxG interactions play an important role in uncovering the genetic structure of complex traits, the statistical methods for detecting GxG interactions in multiple phenotypes remains less developed owing to its potential complexity. Therefore, we extend functional regression model from single variate to multivariate for simultaneous GxG interaction analysis of multiple correlated phenotypes. Large-scale simulations are conducted to evaluate Type I error rates for testing interaction between two genes with multiple phenotypes and to compare power with traditional multivariate pair-wise interaction analysis and single trait interaction analysis by a single variate functional regression model. To further evaluate performance, the MFRG for interaction analysis is applied to five phenotypes of exome sequence data from the NHLBI’s Exome Sequencing Project (ESP) to detect pleiotropic GxG interactions. 267 pairs of genes that formed a genetic interaction network showed significant evidence of interactions influencing five traits.

Cholesteryl ester transfer protein gene polymorphism (I405V) and premature coronary artery disease in an Iranian population

The effect of human cholesteryl ester transfer protein (CETP) expression on atherogenesis is still under debate. The rs5882 (I405V) polymorphism affect CETP function. We aimed to examine the relationship between the rs5882 polymorphism and the risk of angiographically determined coronary artery disease (CAD). To define premature CAD (PCAD), an age cutoff of 55 years for women and 45 years for men was used. An age- and sex-matched case-control study was conducted in 560 patients with newly diagnosed angiographically documented PCAD (≥50% luminal stenosis of any coronary vessel) and an equal number of control patients with normal coronary arteries (no luminal stenosis at coronary arteries). The severity of CAD was determined by vessel score and Gensini score. A real-time polymerase chain reaction (PCR) and high resolution melting analysis were used to distinguish between genotypes. The I405V genotype distributions were not statistically different in CAD and non-CAD groups in univariate and multivariable-adjusted logistic regression analyzes. The median and inter-quartile range for Gensini score was not significantly different among the AA (43, 24 to 73), AG (40, 20 to 66), and GG (45, 25 to 72) genotypes (p = 0.097). Furthermore, the distribution of vessel score did not statistically differ between these genotypes (p = 0.691). Our results suggest that there is no significant association between CETP I405V polymorphism and the risk of PCAD presence and severity. Larger prospective studies are needed to investigate such associations in different populations.

Association of the variants in the PPARG gene and serum lipid levels: a meta-analysis of 74 studies

Considerable studies have been carried out to investigate the relationship between the polymorphisms of PPARG (Pro12Ala, C161T and C1431T) and serum lipid levels, but the results were inconclusive. Hence, we conducted a meta-analysis to clarify the association. MEDLINE, EMBASE and the Cochrane Library databases were searched systematically. The subgroup analysis was performed based on ethnicity. Seventy-four studies with 54,953 subjects were included in this meta-analysis. In Pro12Ala, the group with the ‘PP’ (C/C genotype) genotype group had lower levels of total cholesterol (TC) (mean difference, MD: −0.02, P < 0.00001; I² = 28%), low-density lipoprotein cholesterol (LDL-C) (MD: −0.02, P < 0.00001; I² = 30%) and higher levels of triglyceride (TG) (MD: 0.06, P < 0.00001; I² = 30%) than the combined ‘PA+AA’ (PA = C/G genotype, AA = G/G genotype) genotype group in Asian population, and the group with the ‘PP’ genotype had higher levels of TG (MD: 0.07, P < 0.02; I² = 67%) than the combined ‘PA+AA’ genotype group in non-Asian population. No statistically significant differences in the levels of TC, TG, high-density lipoprotein cholesterol, LDL-C were detected between different genotypes in C161T(Asian or non-Asian) and C1431T(Asian) polymorphisms. This meta-analysis was a renewed and confirmed study to assess the association between PPARG polymorphisms and serum lipid levels in Asian and non-Asian populations. There is a prominent association between Pro12Ala polymorphism and the levels of TC, LDL-C and TG in Asian population. No statistically significant differences in serum lipid levels were detected between different genotypes in C161T and C1431T polymorphisms.