The association between high-density lipoprotein cholesterol level and cholesteryl ester transfer protein TaqIB gene polymorphism is influenced by alcohol drinking in a population-based sample

A Nutrigenetic Update on CETP Gene–Diet Interactions on Lipid-Related Outcomes

Purpose of Review

An abnormal lipid profile is considered a main risk factor for cardiovascular diseases and evidence suggests that single nucleotide polymorphisms (SNPs) in the cholesteryl ester transfer protein (CETP) gene contribute to variations in lipid levels in response to dietary intake. The objective of this review was to identify and discuss nutrigenetic studies assessing the interactions between CETP SNPs and dietary factors on blood lipids.

Recent Findings

Relevant articles were obtained through a literature search of PubMed and Google Scholar through to July 2021. An article was included if it examined an interaction between CETP SNPs and dietary factors on blood lipids. From 49 eligible nutrigenetic studies, 27 studies reported significant interactions between 8 CETP SNPs and 17 dietary factors on blood lipids in 18 ethnicities. The discrepancies in the study findings could be attributed to genetic heterogeneity, and differences in sample size, study design, lifestyle and measurement of dietary intake. The most extensively studied ethnicities were those of Caucasian populations and majority of the studies reported an interaction with dietary fat intake. The rs708272 (TaqIB) was the most widely studied CETP SNP, where ‘B1’ allele was associated with higher CETP activity, resulting in lower high-density lipoprotein cholesterol and higher serum triglycerides under the influence of high dietary fat intake.

Summary

Overall, the findings suggest that CETP SNPs might alter blood lipid profiles by modifying responses to diet, but further large studies in multiple ethnic groups are warranted to identify individuals at risk of adverse lipid response to diet.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11883-022-00987-y.

Quantile-Dependent Expressivity and Gene-Lifestyle Interactions Involving High-Density Lipoprotein Cholesterol

BACKGROUND

The phenotypic expression of a high-density lipoprotein (HDL) genetic risk score has been shown to depend upon whether the phenotype (HDL-cholesterol) is high or low relative to its distribution in the population (quantile-dependent expressivity). This may be due to the effects of genetic mutations on HDL-metabolism being concentration dependent.

METHOD

The purpose of this article is to assess whether some previously reported HDL gene-lifestyle interactions could potentially be attributable to quantile-dependent expressivity.

SUMMARY

Seventy-three published examples of HDL gene-lifestyle interactions were interpreted from the perspective of quantile-dependent expressivity. These included interactive effects of diet, alcohol, physical activity, adiposity, and smoking with genetic variants associated with the ABCA1, ADH3, ANGPTL4, APOA1, APOA4, APOA5, APOC3, APOE, CETP, CLASP1, CYP7A1, GALNT2, LDLR, LHX1, LIPC, LIPG, LPL, MVK-MMAB, PLTP, PON1, PPARα, SIRT1, SNTA1,and UCP1genes. The selected examples showed larger genetic effect sizes for lifestyle conditions associated with higher vis-à-vis lower average HDL-cholesterol concentrations. This suggests these reported interactions could be the result of selecting subjects for conditions that differentiate high from low HDL-cholesterol (e.g., lean vs. overweight, active vs. sedentary, high-fat vs. high-carbohydrate diets, alcohol drinkers vs. abstainers, nonsmokers vs. smokers) producing larger versus smaller genetic effect sizes. Key Message: Quantile-dependent expressivity provides a potential explanation for some reported gene-lifestyle interactions for HDL-cholesterol. Although overall genetic heritability appears to be quantile specific, this may vary by genetic variant and environmental exposure.

Genetic variations of cholesteryl ester transfer protein and diet interactions in relation to lipid profiles and coronary heart disease: a systematic review

Data on diet–genotype interactions in the prevention or treatment of dyslipidemia have increased remarkably. This systematic review aimed to assess nutrigenetic studies regarding the modulating effect of diet on cholesteryl ester transfer protein (CETP) polymorphisms in relation to metabolic traits.

Data were collected through studies published between 2000 and SEP. 2016 using five electronic databases. The quality of eligible studies was assessed using a 12-item quality checklist, derived from the STrengthening the REporting of Genetic Association Studies (STREGA) statement. CETP variants that had associations with lipid profiles in previous studies were extracted for drawing of the linkage disequilibrium (LD) plot.

Among CETP variants, the rs9989419 best represented this genome wide association signal across all populations, based on LD r² estimates from 1000 genomes references. In the 23 found eligible studies (clinical trials and observational), the TaqIB and I405V polymorphisms were the two most intensively studied. Two studies reported the effect of interaction between rs3764261 and diet on lipid levels. Regarding the rs708272 (Taq1B), individuals with the B1 risk allele showed better responses to dietary interventions than those with B2B2 genotype, whereas with I405V, inconsistent results have been reported. Modest alcohol consumption was associated with decreased risk of coronary heart disease among B2 carriers of rs708272.

It is concluded that variations in the CETP gene may modulate the effects of dietary components on metabolic traits. These results have been controversial, indicating complex polygenic factors in metabolic response to diet and lack of uniformity in the study conditions and designs.

Association of Cholesteryl Ester Transfer Protein and Endothelial Nitric Oxide Synthase Gene Polymorphisms With Coronary Artery Disease in the Multi-Ethnic Malaysian Population

Genetic variants of cholesteryl ester transfer protein (CETP) and endothelial nitric oxide synthase (eNOS) influence high-density lipoprotein cholesterol (HDL-C) metabolism and nitric oxide (NO) synthesis, respectively, and might increase the risk of coronary artery disease (CAD). This study is to investigate the relationship between genetic polymorphisms and the risk of CAD and to evaluate their potential interactions. A total of 237 patients with CAD and 101 controls were genotyped. The association of the polymorphism with the risk of CAD varied among the ethnic groups. Moreover, the concomitant presence of both CETP B1 and eNOS 4a alleles significantly increased the risk of CAD in the Malay group (OR = 33.8, P < .001) and the Indian group (OR = 10.9, P = .031) but not in the Chinese group. This study has identified a novel ethnic-specific gene–gene interaction and suggested that the combination of CETP B1 allele and eNOS 4a allele significantly increases the risk of CAD in Malays and Indians.

CETP genotype and changes in lipid levels in response to weight-loss diet intervention in the POUNDS LOST and DIRECT randomized trials

Little is known about whether cholesteryl ester transfer protein (CETP) genetic variation may modify the effect of weight-loss diets varying in fat content on changes in lipid levels. We analyzed the interaction between the CETP variant rs3764261 and dietary interventions on changes in lipid levels among 732 overweight/obese adults from a 2 year randomized weight-loss trial [Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST)], and replicated the findings in 171 overweight/obese adults from an independent 2 year weight-loss trial [Dietary Intervention Randomized Controlled Trial (DIRECT)]. In the POUNDS LOST, participants with the CETP rs3764261 CC genotype on the high-fat diet had larger increases in HDL cholesterol (P = 0.001) and decreases in triglycerides (P = 0.007) than those on the low-fat diet at 6 months, while no significant difference between these two diets was observed among participants carrying other genotypes. The gene-diet interactions on changes in HDL-cholesterol and tri-glyc-erides were replicated in the DIRECT (pooled P for interaction ≤ 0.01). Similar results on trajectory of changes in HDL cholesterol and triglycerides over the 2 year intervention were observed in both trials. Our study provides replicable evidence that individuals with the CETP rs3764261 CC genotype might derive greater effects on raising HDL cholesterol and lowering triglycerides by choosing a low-carbohydrate/high-fat weight-loss diet instead of a low-fat diet.

Single nucleotide polymorphisms in cholesteryl ester transfer protein gene and recurrent coronary heart disease or mortality in patients with established atherosclerosis

It is not known whether genetic variants in the cholesteryl ester transfer protein (CETP) gene are associated with recurrent coronary heart disease events or mortality in secondary prevention patients. Among 3,717 patients with acute coronary syndrome or coronary artery bypass grafting (CABG) enrolled in a prospective genetic registry, we evaluated whether CETP gene variants previously shown to be associated with reduced CETP activity and high-density lipoprotein cholesterol increase ("A" allele for both TaqIB [rs708272] and rs12149545) are associated with a reduction in recurrent myocardial infarction (MI), recurrent revascularization, or death. At 4.5 years of follow-up, 439 recurrent MI, 698 recurrent revascularizations, and 756 deaths occurred. Using an additive model of inheritance, the "A" allele for rs708272 was not associated with recurrent MI (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.78 to 1.17 for AG; HR 0.89, 95% CI 0.67 to 1.19 for AA; compared with GG genotype), recurrent revascularization (HR 1.13, 95% CI 0.95 to 1.33 for AG; HR 1.05, 95% CI 0.84 to 1.32 for AA), or mortality (HR 1.02, 95% CI 0.86 to 1.19 for AG; HR 1.11, 95% CI 0.91 to 1.37 for AA) in the overall cohort. Similar results were seen for the "A" allele for rs12149545. In the CABG subgroup, AG genotype for rs708272 was associated with an increased mortality (HR 1.38, 95% CI 1.06 to 1.79) compared with GG genotype. Results remained consistent using dominant model of inheritance. In conclusion, genetic CETP variants were not associated with recurrent MI or recurrent revascularization in overall cohort with a possible mortality increase in patients who underwent CABG.

Alcohol intake

Alcohol consumption and its association with health or illness states are of great interest from the nutritional genomics point of view. This interest is centered not only on investigating the genetic variants that can modulate the effects of alcoholic beverages on different intermediate and final disease phenotypes (mainly cardiovascular diseases and cancer), but also on finding out how the genome influences the amount of alcohol consumed and consumption habits. This chapter reviews the latest findings on alcohol consumption trends, the methodological limitations in the analysis of alcohol consumption, and the main genes and polymorphisms related to alcohol intake, including the inconsistent results from genome-wide association studies (GWASs). It also reviews the effects of alcohol consumption on cardiovascular diseases and cancer and the studies analyzing the interactions between different genetic polymorphisms and alcohol in phenotypes related to these diseases, discussing the studies' advantages and limitations as well as future research perspectives.

Gene-environment interactions of CETP gene variation in a high cardiovascular risk Mediterranean population

Genome-wide association studies show that cholesteryl ester transfer protein (CETP) single nucleotide polymorphisms (SNPs) are more strongly associated with HDL cholesterol (HDL-C) concentrations than any other loci across the genome. However, gene-environment interactions for clinical applications are still largely unknown. We studied gene-environment interactions between CETP SNPs and dietary fat intake, adherence to the Mediterranean diet, alcohol consumption, smoking, obesity, and diabetes on HDL-C in 4,210 high cardiovascular risk subjects from a Mediterranean population. We focused on the -4,502C>T and the TaqIB SNPs in partial linkage disequilibrium (D'= 0.88; P < 0.001). They were independently associated with higher HDL-C (P < 0.001); this clinically relevant association was greater when their diplotype was considered (14% higher in TT/B2B2 vs. CC/B1B1). No gene-gene interaction was observed. We also analyzed the association of these SNPs with blood pressure, and no clinically relevant associations were detected. No statistically significant interactions of these SNPs with obesity, diabetes, and smoking in determining HDL-C concentrations were found. Likewise, alcohol, dietary fat, and adherence to the Mediterranean diet did not statistically interact with the CETP variants (independently or as diplotype) in determining HDL-C. In conclusion, the strong association of the CETP SNPs and HDL-C was not statistically modified by diet or by the other environmental factors.

Association of two CETP polymorphisms with HDL levels in the Chinese obese population

The association of two cholesterol ester transfer protein (CETP) polymorphisms, D442G and TAQIB (B1-->B2), with high-density lipoprotein (HDL) levels in 932 Chinese obese individuals (BMI >or= 27) was investigated in comparison with normal controls (BMI <or= 24). Independent association was demonstrated for TAQIB minor allele B2 and CETP442 minor allele G with elevated HDL levels. The CETP D442G polymorphism was associated with a much greater increase in HDL levels in subjects with BMI exceeding 27 kg/m(2) (+5.42 mg/dl, P = 0.0007) compared to normal controls (+1.97 mg/dl, P = 0.275), and the increase in HDL reached the highest level among subjects with BMI exceeding 30 kg/m(2) (+6.80 mg/dl, P = 0.016). TAQIB showed significant association with HDL levels only in normal BMI subgroup (P = 0.0017). TAQIB significantly interacted with serum triglyceride (TG) on modulating HDL levels (P = 0.027). The TAQIB-TG interaction effect remained marginally significant after controlling for BMI (P = 0.057). We conclude that D442G polymorphism is associated with more HDL elevation in obesity. TAQIB interacts with serum TG on modulating HDL levels, and the interaction is partly independent of BMI.

Association of the cholesteryl ester transfer protein Taq1 B2B2 genotype with higher high-density lipoprotein cholesterol concentrations and lower risk of coronary artery disease in a Tunisian population

BACKGROUND

The role of cholesteryl ester transfer protein (CETP) in the development of atherosclerosis is undergoing debate.

AIMS

In this prospective study, we sought to explore the role of the CETP Taq1B variant in coronary artery disease risk, and its association with plasma lipid and apolipoprotein concentrations.

METHODS

DNA was extracted from 316 patients undergoing coronary angiography. The Taq1B polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism analysis. Lipid and apolipoprotein concentrations were measured by enzymatic and nephelometric assays.

RESULTS

In our study population, the B2 allele frequency was 0.29. B2 allele carriers had a significantly higher high-density lipoprotein cholesterol (HDL-C) concentration than those with the B1B1 genotype (1.041+/-0.294 versus 0.995+/-0.277; p=0.039). After adjusting for age, sex, smoking status, diabetes, hypertension and dyslipidaemia, the odds ratio (OR) for significant stenosis associated with the B2 allele was 0.82 (95% confidence interval (CI) 0.60-0.97; p=0.039), suggesting that the B2 allele is associated with an 18% lower risk of significant stenosis. This protective effect seemed to be more significant in male nonsmokers (38% lower risk; OR 0.62, 95% CI 0.29-0.92; p=0.029). No significant protective effects were observed in women or male smokers.

CONCLUSION

Our data suggest that the B2 allele is associated with higher concentrations of HDL-C, which confer a protective effect with regard to coronary atherosclerosis. This effect seems to be more significant in men than in women and in nonsmokers than in smokers.

Genetic-epidemiological evidence on genes associated with HDL cholesterol levels: a systematic in-depth review

High-density lipoprotein (HDL) particles exhibit multiple antiatherogenic effects. They are key players in the reverse cholesterol transport which shuttles cholesterol from peripheral cells (e.g. macrophages) to the liver or other tissues. This complex process is thought to represent the basis for the antiatherogenic properties of HDL particles. The amount of cholesterol transported in HDL particles is measured as HDL cholesterol (HDLC) and is inversely correlated with the risk for coronary artery disease: an increase of 1mg/dL of HDLC levels is associated with a 2% and 3% decrease of the risk for coronary artery disease in men and women, respectively. Genetically determined conditions with high HDLC levels (e.g. familial hyperalphalipoproteinemia) often coexist with longevity, and higher HDLC levels were found among healthy elderly individuals. HDLC levels are under considerable genetic control with heritability estimates of up to 80%. The identification and characterization of genetic variants associated with HDLC concentrations can provide new insights into the background of longevity. This review provides an extended overview on the current genetic-epidemiological evidence from association studies on genes involved in HDLC metabolism. It provides a path through the jungle of association studies which are sometimes confusing due to the varying and sometimes erroneous names of genetic variants, positions and directions of associations. Furthermore, it reviews the recent findings from genome-wide association studies which have identified new genes influencing HDLC levels. The yet identified genes together explain only a small amount of less than 10% of the HDLC variance, which leaves an enormous room for further yet to be identified genetic variants. This might be accomplished by large population-based genome-wide meta-analyses and by deep-sequencing approaches on the identified genes. The resulting findings will probably result in a re-drawing and extension of the involved metabolic pathways of HDLC metabolism.

Interactions between alcohol intake and the polymorphism of rs708272 on serum high-density lipoprotein cholesterol levels in the Guangxi Hei Yi Zhuang population

Both alcohol consumption and the polymorphism of the cholesteryl ester transfer protein (CETP) TaqIB gene (rs708272) influence plasma high-density lipoprotein cholesterol (HDL-C) levels. However, their interactions on serum HDL-C levels is not well known. The present study was undertaken to detect the interactions between alcohol consumption and the rs708272 polymorphism on serum lipid levels in the Guangxi Hei Yi Zhuang population. Genotyping of the rs708272 in 342 nondrinkers and 416 drinkers aged 15-70 years was performed by polymerase chain reaction and restriction fragment length polymorphism. Interactions between rs708272 genotype and alcohol consumption was assessed using a cross-product term between genotypes and the aforementioned factor. Statistical significance was evaluated with analysis of co-variance. The frequency of B1 allele was 65.8% in nondrinkers and 64.7% in drinkers (P>.05), respectively. The frequencies of B1B1, B1B2, and B2B2 genotypes were 45.0%, 41.5%, and 13.5% in nondrinkers, and 41.3%, 46.6%, and 12.0% in drinkers (P>.05), respectively. The levels of HDL-C and apolipoprotein (Apo) AI in nondrinkers were higher in B2B2 genotype than in B1B1 genotype (P<.05 for each), whereas triglyceride (TG) levels in drinkers were higher in B1B1 genotype than in B1B2 genotype (P<.05). The levels of TG, HDL-C, Apo AI in B1B1 genotype, and HDL-C and Apo AI in B1B2 genotype were higher in drinkers than in nondrinkers (P<.05-.01), whereas the levels of low-density lipoprotein cholesterol (LDL-C) and Apo B in B2B2 genotype, and the levels of LDL-C in B1B1 genotype were lower in drinkers than in nondrinkers (P<.05-.01). The levels of HDL-C were positively correlated with female sex and genotype in nondrinkers (P<.001 for each), and were positively associated with age and alcohol consumption in drinkers (P<.005 and<.01, respectively). This study suggests that the B1 carriers benefited more from alcohol consumption than the B2 carriers in increasing serum HDL-C and Apo AI levels, and lowering LDL-C levels.

Common variation in the CETP gene and the implications for cardiovascular disease and its treatment: an updated analysis

Human plasma contains cholesteryl ester transfer protein (CETP) which, besides other functions, enables the transfer of cholesteryl esters in plasma from high-density lipoproteins (HDL) towards triglyceride-rich lipoproteins, thereby contributing to lower HDL cholesterol. Variations in the CETP gene, including the intronic TaqIB polymorphism (rs708272), are common in the population. Although HDL cholesterol is approximately 10% higher in TaqIB B2B2 than in B1B1 carriers, the association of this polymorphism with cardiovascular disease has not been unequivocally established. We present an updated pooled analysis concerning the association of cardiovascular disease with the TaqIB polymorphism, including only studies that predominantly comprise Caucasian subjects. The distribution of this CETP genotype was observed to be different in population-based studies (n = 10,526) compared with studies in populations selected by high cardiovascular risk (n = 10,947), with B2B2 carriers being less frequent among cases from high-risk populations compared with cases from population-based studies (p = 0.0009 for the difference in genotype distribution). In population-based studies, the odds ratio (OR) for cardiovascular disease was found to be 1.45 (95% CI: 1.07–1.95) in B2B2 compared with B1B1 carriers, contrasting the lower OR of 0.84 (95% CI: 0.74–0.96) in B2B2 versus B1B1 carriers from high-risk populations. Thus, it is possible that in the general population, the B2 allele is associated with higher cardiovascular risk, despite higher HDL cholesterol. Our analysis agrees with the contention that selection towards a lower frequency of B2B2 homozygotes may have occurred in selected populations, which would result in a apparently protective effect of the B2 allele when determined in high-risk populations. We also evaluated whether the TaqIB polymorphism would predict efficacy of lipid-lowering treatment with respect to plasma lipids and cardiovascular outcome, but the results of published studies were contradictory. Likewise, no definite conclusion can be made at present concerning the effect of this CETP polymorphism on the lipid response to diet intervention.

Why study gene-environment interactions?

PURPOSE OF REVIEW

We examine the reasons for investigating gene-environment interactions and address recent reports evaluating interactions between genes and environmental modulators in relation to cardiovascular disease and its common risk factors.

RECENT FINDINGS

Studies focusing on smoking, physical activity, and alcohol and coffee consumption are observational and include relatively large sample sizes. They tend to examine single genes, however, and fail to address interactions with other genes and other correlated environmental factors. Studies examining gene-diet interactions include both observational and interventional designs. These studies are smaller, especially those including dietary interventions. Among the reported gene-diet interactions, it is important to highlight the strengthened position of APOA5 as a major gene that is involved in triglyceride metabolism and modulated by dietary factors, and the identification of APOA2 as a modulator of food intake and obesity risk.

SUMMARY

The study of gene-environment interactions is an active and much needed area of research. Although technical barriers of genetic studies are rapidly being overcome, inclusion of comprehensive and reliable environmental information represents a significant shortcoming of genetics studies. Progress in this area requires inclusion of larger populations but also more comprehensive, standardized, and precise approaches to capturing environmental information.

Genetic determinants of plasma lipoproteins

The search for common genetic determinants of plasma lipoproteins began in the early 1980s. Despite some exceptions, these efforts have not yet yielded a set of biological markers that can be used in clinical practice. By contrast, successes in defining the molecular basis of rare single-gene disorders, such as familial hypoalphalipoproteinemia, have shown the value of experimental designs that focus on genomic analysis of individuals within the tails of Gaussian distributions of quantitative lipoprotein traits. For example, this strategy showed that a small but relevant proportion of individuals within the <5% tail of plasma HDL-cholesterol distribution have mutations in genes that cause familial hypoalphalipoproteinemia. The value of clinical testing for genomic variants as an adjunct to a biochemical measurement of plasma lipoproteins, however, is at best questionable. A more direct impact of genetic studies is that definitions of 'common' and 'large genetic effects' have become more tempered, reflecting perhaps the biological reality that plasma lipoproteins are probably determined by the aggregate of numerous modest and occasional large genetic effects in addition to environmental factors. Here, we review recent progress on genomic variants and cholesterol metabolism, and discuss the impact these genetic studies will have on clinical cardiology.