Apolipoprotein E gene polymorphism and risk for coronary heart disease in the Chinese population: a meta-analysis of 61 studies including 6634 cases and 6393 controls

The association of apolipoprotein-E (APOE) gene polymorphisms with coronary artery disease: a systematic review and meta-analysis

Background

Numerous studies have investigated the role of apolipoprotein E (APOE) polymorphisms in coronary artery disease (CAD), but some controversies exist regarding the outcomes as the results were not consistent and remain uncertain. Therefore, the present meta-analysis was conducted to evaluate the association of APOE polymorphisms with coronary artery disease.

Methods

All the relevant studies published in English language till August 2020 were identified by searching through various electronic databases. The complete data was independently extracted by the two researchers. The data were analyzed by using the Comprehensive Meta-Analysis program and MetaGenyo program. The pooled odds ratio was used to check the associations between CAD and APOE polymorphisms. The following genetic models were used to calculate the odds ratio: ε2 vs. ε3 and ε4 vs. ε3.

Results

In the final analysis, we include 12 studies regarding the role of APOE polymorphism in CAD. The pooled odds ratio for ε4 allele was higher (OR 2.00; 95% and CI, 1.48–2.71). There is no statistical significant association for ε2 allele with CAD (OR 1.38; 95% CI, 1.18–1.62). This analysis showed no publication bias exists in the current meta-analysis.

Conclusions

Our findings suggest that the apolipoprotein ε4 allele appears as a significant genetic risk factor for coronary artery disease while the ε2 allele is beneficial to alleviate the CAD risk.

Trial registration

Registered with PROSPERO International Prospective Register of Systematic Reviews. PROSPERO registration number CRD42020190464

APOE Gene Associated with Cholesterol-Related Traits in the Hispanic Population

Genetic variants in the apolipoprotein E (APOE) gene are associated with lipid metabolism and lipid-related traits in the non-Hispanic population. There have been limited studies regarding the association between the APOE gene and hypercholesterolemia in the Hispanic population; therefore, our aim for this study is to examine the APOE gene’s associations with cholesterol level and its related phenotypes. The APOE gene consists of three different alleles, ε2, ε3, and ε4, with ε4 being associated with dementia and cardiovascular diseases. A total of 1,382 subjects were collected from the Texas Alzheimer’s Research and Care Consortium (TARCC, N = 1320) and the Initial Study of Longevity and Dementia from the Rio Grande Valley (ISLD-RGV, N = 62). Questionnaires on demographics, medical history, and blood/saliva samples were collected and APOE genotypes were performed. We observed allele frequencies of the APOE ε3 (96.7%), ε4 (22.6%) and ε2 (6.8%) alleles, respectively. Multivariable logistic regression revealed a significant association between the APOE ε4 allele and hypercholesteremia (p = 1.8 × 10⁻⁴) in our studied Hispanic population. We prove for the first time, that the APOE ε4 allele increases the risk for hypercholesterol in Hispanics. Further research is needed to confirm and supports our current findings.

Mediation of the APOE associations with Alzheimer's and coronary heart diseases through body mass index and lipids

The APOE ε2/ε3/ε4 polymorphism is associated with multiple non-Mendelian traits, including high- (HDL-C) and low- (LDL-C) density lipoprotein cholesterol, triglycerides, body mass index (BMI), coronary heart disease (CHD), and Alzheimer's disease (AD). Lipids and BMI are risk factors for AD and CHD. Causal connections between the ε2 and ε4 alleles and these traits remain, however, poorly understood. We leverage comprehensive analyses of longitudinal data from four studies to examine potentially causal heterogeneous connections between these alleles, lipids, BMI, and diseases. We emphasize mutual mediation roles of lipids and BMI in their associations with the ε2 and ε4 alleles and their mediation roles in the associations of these alleles with AD and CHD. We confirmed previously reported significant univariate associations of these alleles with each trait, except CHD. We found, however, that most of the univariate- and mediation-analysis associations were affected by antagonistic heterogeneity/mediation. The mutual mediation analysis identified the associations of the APOE alleles with LDL-C as the least heterogeneous. The ε2 and ε4 alleles were associated with CHD through lipids, led by beneficial (β_IE =  - 0.071, p_IE = 2.28 × 10^-10) and adverse (β_IE = 0.019, p_IE = 7.37 × 10^-6) associations, respectively, through LDL-C. Both these alleles were adversely associated with CHD through triglycerides. For AD, only BMI partially mediated the adverse association of the ε4 allele with AD (β_IE = 0.016, p_IE = 2.09 × 10^-2). Our results suggest different roles of BMI and lipids in the AD and CHD pathogeneses. More comprehensive studies of causal connections between genetic variants and non-Mendelian traits are required as they can be critically affected by heterogeneous antagonistic relationships.

APOE gene ɛ4 allele (388C-526C) effects on serum lipids and risk of coronary artery disease in southern Chinese Hakka population

OBJECTIVE

To analyze the relationship of Apolipoprotein E (APOE) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene polymorphisms with coronary artery disease (CAD).

METHODS

1,129 CAD patients and 1,014 non-CAD controls were included in the study, and relevant information and medical records were collected. The single-nucleotide polymorphisms (SNPs) were analyzed, including rs429358, rs7412 in APOE gene and rs2306283, rs4149056 in SLCO1B1 gene.

RESULTS

The CAD patients' average age was 66.3 ± 10.7 years, while 65.5 ± 12.0 years in controls. The frequencies of APOE allele ɛ3, ɛ4, and ɛ2 were 83.01%, 10.08%, and 6.91% respectively. There were statistically significant differences in genotype ɛ3/ɛ4 (χ²  = 8.077, p = 0.005) in CAD patients compared with the controls. The SLCO1B1 genotype *1b/*1b and haplotype *1b showed the highest frequency in the study sample. Moreover, ε4 carriers had significantly lower HDL-C, Apo-A1 levels than ε3 carriers among CAD patients, while ε2 carriers showed lower LDL-C, Apo-B level, and higher Apo-A1/Apo-B level than ε3 and ε4 carriers. In controls, ε2 carriers showed lower LDL-C and Apo-B level, higher Apo-A1, and Apo-A1/Apo-B level than ε4 carriers. Logistic regression analysis showed that high LDL-C and Apo-B level, low HDL-C level, smoking, and the ε4 allele were risks for the presence of CAD.

CONCLUSIONS

APOE ε4 allele may be associated with susceptibility to CAD in southern Chinese Hakka population. It indicated that the APOE SNPs rs429358 and rs7412 are associated with CAD, but not SNPs rs2306283 and rs4149056 of SLCO1B1 gene.

HDL in Atherosclerotic Cardiovascular Disease: In Search of a Role

For a long time, high-density lipoprotein cholesterol (HDL-C) has been regarded as a cardiovascular disease (CVD) protective factor. Recently, several epidemiological studies, while confirming low plasma levels of HDL-C as an established predictive biomarker for atherosclerotic CVD, indicated that not only people at the lowest levels but also those with high HDL-C levels are at increased risk of cardiovascular (CV) mortality. This “U-shaped” association has further fueled the discussion on the pathophysiological role of HDL in CVD. In fact, genetic studies, Mendelian randomization approaches, and clinical trials have challenged the notion of HDL-C levels being causally linked to CVD protection, independent of the cholesterol content in low-density lipoproteins (LDL-C). These findings have prompted a reconsideration of the biological functions of HDL that can be summarized with the word “HDL functionality”, a term that embraces the many reported biological activities beyond the so-called reverse cholesterol transport, to explain this lack of correlation between HDL levels and CVD. All these aspects are summarized and critically discussed in this review, in an attempt to provide a background scenario for the “HDL story”, a lipoprotein still in search of a role.

Association of Apolipoprotein E Polymorphism with Adipokines and Cardiovascular Disease Risk in Rheumatoid Arthritis Patients

Apolipoprotein E (ApoE) polymorphism and adipokines are linked to atherosclerosis. We aimed to investigate the associations of apoE genotypes with adipokines, inflammatory parameters, and cardiovascular disease (CVD) risks in rheumatoid arthritis (RA) patients. We enrolled 152 RA patients and 49 healthy control (HC) subjects. The apoE genotyping was determined by a polymerase chain reaction, while plasma levels of adipokines and inflammatory cytokines were measured with ELISA. Although apoE genotypes distributions were indistinguishable between RA patients and HC, we found significantly higher levels of apoE and adipokines in RA patients compared with HC. RA patients with ε2ε3 genotype had lower levels of TNF-α, IL-6, resistin, and visfatin, but higher leptin levels compared with ε3ε3 genotype patients. Patients with ε3ε4 genotype had significantly higher low-density lipoprotein-cholesterol (LDL-C) levels and atherogenic index scores compared with ε2ε3 genotype carriers. Moreover, patients with ε2ε3 genotype had significantly lower 10-year CVD risk than ε3ε3 or ε3ε4 genotype patients. ε3ε4 genotype and adiponectin levels were independent predictors of a high 10-year CVD risk. RA patients with ε2ε3 genotype are associated with lower levels of TNF-α, IL-6, resistin, visfatin, and CVD risk, while RA patients with ε3ε4 genotype exhibited higher levels of LDL-C, insulin resistance, and higher CVD risks.

Application of Genome-Wide Association Studies in Coronary Artery Disease

Coronary artery disease (CAD) is a complex disease caused by the combination of environmental and genetic factors. It is one of the leading causes of death and disability in the world. Much research has been focussed on CAD genetic mechanism. In recent years, genome-wide association study (GWAS) has developed rapidly around the world. Medical researchers around the world have successfully discovered a series of CAD genetic susceptibility genes or susceptible loci using medical research strategies, leading CAD research toward a new stage. This paper briefly summarizes the important progress made by GWAS for CAD in the world in recent years, and then analyzes the challenges faced by GWAS at this stage and the development trend of future research, to promote the transformation of genetic research results into clinical practice and provide guidance for further exploration of the genetic mechanism of CAD.

Causal association of circulating cholesterol levels with dementia: a mendelian randomization meta-analysis

Prospective studies have shown that abnormally circulating cholesterol is associated with the risk of dementia. However, whether the association is causal or not remains unclear. We attempt to infer the causal association in a MR meta-analysis by using ApoE gene polymorphisms as instrument variables. Studies with dementia risk (27 studies) or circulating lipid levels (7 studies) were included, with totally 3136 dementia patients and 3103 healthy controls. The analyses showed that carriers of ε2 allele significantly were of decreased risk of AD (OR = 0.70; 95% CI: 0.58-0.84; P < 0.01), whereas carriers of ε4 allele were of increased risk of AD (OR = 3.62; 95% CI: 3.03-4.32; P < 0.05), compared to these of ε3 allele. Circulating TC was significantly reduced in carriers of ε2 allele (WMD = - 0.29 mmol/L; 95% CI: -0.54 to -0.03; P < 0.05) and increased in carriers of ε4 allele (WMD = 0.42 mmol/l; 95% CI: 0.001-0.84; P < 0.05). In addition, carriers of ε4 allele had reduction in circulating HDL-C (WMD = - 0.04 mmol/L; 95% CI: - 0.07 to -0.001; P < 0.05). In comparing allele ε2 with ε3, the predicted OR of having AD for 1 mg/dL increment in circulating TC was 0.97 (95% CI: 0.86-0.98; P < 0.05). Comparing allele ε4 with ε3, the predicted OR for a 1 mg/dL increment in TC was 1.08 (95% CI: 1.05-17.58; P < 0.05), and reduction in HDL-C was 2.30 (95% CI: 1.51-43.99; P < 0.05). Our findings demonstrate that high circulating TC and reduced HDL-C levels might be potential risk factors of the development of AD.

Gene Influence in the Effectiveness of Plant Sterols Treatment in Children: Pilot Interventional Study

Cardiovascular disease is linked to high serum low density lipoprotein (LDL)-cholesterol levels. Cardiovascular risk may be indirectly influenced by genetic load. Serum LDL-cholesterol levels may be reduced by the consumption of food enriched with plant sterols (PS). The aim was to test a plant sterol treatment on cholesterol levels according to different genetic polymorphisms. A pilot interventional trial was performed in 26 children (n = 16 girls, n = 10 boys). Seven hundred milliliters/day of commercial skimmed milk with added plant sterols delivering 2.2 g plant sterols were ingested for three weeks. Blood draws were performed at the baseline and end of the study. Significant modifications of non-high density lipoprotein (HDL)-cholesterol (p = 0.010; p = 0.013) and LDL-cholesterol (p = 0.004; p = 0.013) levels appeared in the genes LIPC C-514T and PPAR-α L162V carriers. No statistically significant differences were observed for other genes. LIPC C-514T and PPAR-alpha L162V carriers could benefit from a plant sterol supplement to ameliorate hypercholesterolemia.

ApoE Genotype, Lipid Profile, Exercise, and the Associations With Cardiovascular Morbidity and 18-Year Mortality

Background

Studies of longevity examined apolipoprotein E (ApoE), a gene involved in lipoprotein metabolism, which interacts with susceptibility to age-related diseases, and with mortality. We evaluated the association of ApoE isoforms with cardiovascular disease (CVD) and all-cause mortality.

Methods

A prospective cohort of 949 survivors of the Israel Study of Glucose Intolerance, Obesity, and Hypertension, examined during 1999–2004, mean age 72 years, was followed for mortality until 2017. Participants were interviewed for lifestyle habits and medical history. Anthropometrics and biochemical markers were taken. Logistic regression was used to assess CVD morbidity and Cox proportional hazard model for mortality.

Results

The most common genotype in the cohort was ApoE E3 (76.3%), with the other two almost equally distributed (ApoE E2 11.2% and ApoE E4 12.5%). In men only, ApoE E4 associated with CVD (adjusted odds ratio = 1.46, 95% confidence interval [CI] 0.76, 2.80) and with 18-year mortality (adjusted hazard ratio = 1.47, 95% CI 0.95, 2.26), adjusting for age, ethnicity, physical activity, hypertension, diabetes, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglycerides and lipid-lowering medications. Low levels of HDL cholesterol, adjusted for ApoE and the above-mentioned variables, associated with higher prevalence of CVD (adjusted odds ratio = 1.35, 95% CI 1.00, 1.83) and all-cause mortality (adjusted hazard ratio = 1.42, 95% CI 1.14, 1.78). ApoE E3 and E2 conferred a lower 18-year mortality risk in the physically active individuals, compared to the sedentary (adjusted hazard ratio = 0.57, 95% CI 0.44, 0.74, and adjusted hazard ratio = 0.53, 95% CI 0.78, 1.02, respectively).

Conclusions

In community-dwelling older adults, sociodemographic characteristics and physical activity, blood pressure and HDL-cholesterol levels, may outweigh the impact of ApoE polymorphisms on CVD morbidity and all-cause mortality.

Modulation of plasma triglycerides concentration by sterol-based treatment in children carrying different genes

BACKGROUND

Dyslipidemias have increased during the last decades in children.

AIM

The objective of this study was to analyze the influence of different polymorphisms in plasma triglyceride levels of children following a dietary treatment with plant sterols.

DESIGN

A randomized, double-blind, crossover, controlled clinical trial was carried out in 26 children (16 women).

MATERIALS AND METHODS

Commercial milk, with 2.24 g sterols, was ingested daily during 3 weeks , and the same amount of kimmed milk without sterols, during the 3 week placebo phase. Both phases were separated by a washout period of 2 weeks. At the beginning and end of each phase, blood draws were performed.

RESULTS

Apolipoprotein A5 Ser19Trp (P = 0.002), peroxisome proliferator-activated receptor-alpha L162V (P = 0.003), APOE APOE2/3/4 (P = 0.012), and APOE APOE2,3,4 (P = 0.025) show statistically significant differences between their haplotypes in plasma triglyceride levels. Other genes did not show statistically significant differences.

CONCLUSIONS

Further studies are needed to establish which genotype combinations would be the most protective against hypertriglyceridemia.

The Genetic Variability of APOE in Different Human Populations and Its Implications for Longevity

Human longevity is a complex phenotype resulting from the combinations of context-dependent gene-environment interactions that require analysis as a dynamic process in a cohesive ecological and evolutionary framework. Genome-wide association (GWAS) and whole-genome sequencing (WGS) studies on centenarians pointed toward the inclusion of the apolipoprotein E (APOE) polymorphisms ε2 and ε4, as implicated in the attainment of extreme longevity, which refers to their effect in age-related Alzheimer's disease (AD) and cardiovascular disease (CVD). In this case, the available literature on APOE and its involvement in longevity is described according to an anthropological and population genetics perspective. This aims to highlight the evolutionary history of this gene, how its participation in several biological pathways relates to human longevity, and which evolutionary dynamics may have shaped the distribution of APOE haplotypes across the globe. Its potential adaptive role will be described along with implications for the study of longevity in different human groups. This review also presents an updated overview of the worldwide distribution of APOE alleles based on modern day data from public databases and ancient DNA samples retrieved from literature in the attempt to understand the spatial and temporal frame in which present-day patterns of APOE variation evolved.

The inverted pattern of circulating miR-221-3p and miR-222-3p associated with isolated low HDL-C phenotype

BACKGROUND

We investigated the baseline characterization of cardiovascular disease (CVD)-derived circulating miR-221-3p/222-3p in isolated low HDL-C phenotype (ILHP) to enhance our understanding on their molecular pathological pattern prior to disease onset.

METHODS

We screened 174 asymptomatic subjects with isolated low HDL-C phenotype (n = 88) and normal lipid phenotype (n = 86), and detected circulating levels of CVD-derived circulating miR-221-3p/222-3p using TaqMan miRNA Real-time PCR detection system.

RESULTS

We found the inverted pattern of decreased circulating miR-221-3p (0.415 [0.249, 1.004] vs 0.658 [0.347, 1.534], p = 0.002) versus increased miR-222-3p levels (0.379 [0.101, 0.701] vs 0.156 [0.043, 0.407], p < 0.001) in ILHP. The baseline levels of circulating miR-221-3p and miR-222-3p are correlated with serum HDL-C levels (miR-221-3p: r = 0.306, p < 0.001; miR-222-3p: r = - 0.201, p = 0.008). Gender-based analysis showed female-specific elevation of circulating miR-221-3p in asymptomatic individual. Multiple logistic regression analysis showed that circulating miR-222-3p is robustly independent factor (adjusted OR = 8.42, 95%CI: 2.53-27.98, p < 0.001) and significantly improved the performance of the predictive clinical model distinguished ILHP from normal lipid phenotype (AUC: 0.816, 95%CI (0.754, 0.879) vs AUC: 0.771, 95%CI (0.702, 0.840); Z = 2.169, p = 0.030). Moreover, the increased original Ct ratio of miR-221-3p to miR-222-3p in male ILHP (1.003 [0.927, 1.063] vs 0.927 [0.858, 0.967], p < 0.001) significantly enhanced the ability to classify male ILHP compared with the male predictive clinical model (AUC: 0.851, 95%CI (0.770, 0.933) vs AUC: 0.759, 95%CI (0.659, 0.859); Z = 2.474, p < 0.05).

CONCLUSIONS

The inverted pattern of circulating miR-221-3p and miR-222-3p are potentially clinically actionable signature for molecular pathology in isolated low HDL-C phenotype.

Genomic Influence in the Prevention of Cardiovascular Diseases with a Sterol-Based Treatment

Raised serum cholesterol concentration is a well-established risk factor in cardiovascular disease. In addition, genetic load may have an indirect influence on cardiovascular risk. Plant-based sterol-supplemented foods are recommended to help reduce the serum low-density lipoprotein cholesterol level. The objective was to analyse the influence of different polymorphisms in hypercholesterolemia patients following a dietary treatment with plant sterols. A randomised double-blind cross-over controlled clinical trial was carried out in 45 people (25 women). Commercial milk, containing 2.24 g of sterols, was ingested daily during a 3-week period, and then the same amount of skim milk, without sterols, was consumed daily during the 3-week placebo phase. Both phases were separated by a washout period of 2 weeks. At the beginning and end of each phase, blood draws were performed. Genes LIPC C-514T and APOA5 C56G are Ser19Trp carriers and greatly benefit from sterol intake in the diet. LIPC C-514T TT homozygous carriers had lower low-density lipoprotein cholesterol (LDL-c) levels than CC homozygote and CT heterozygote carriers after the ingestion of plant sterols (p = 0.001). These two genes also showed statistically significant changes in total cholesterol levels (p = 0.025; p = 0.005), and no significant changes in high-density lipoprotein (HDL) cholesterol levels (p = 0.032; p = 0.003), respectively. No statistically significant differences were observed for other genes. Further studies are needed to establish which genotype combinations would be the most protective against hypercholesterolemia.

The Associations between Apolipoprotein E Gene Epsilon2/Epsilon3/Epsilon4 Polymorphisms and the Risk of Coronary Artery Disease in Patients with Type 2 Diabetes Mellitus

Background and Objective: Apolipoprotein E (APOE) plays important roles in lipoprotein metabolism and cardiovascular disease. Evidence suggests the APOE gene epsilon2/epsilon3/epsilon4 (ε2/ε3/ε4) polymorphisms might be associated with the susceptibility of coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM). However, no clear consensus has yet been established. Therefore, the aim of this meta-analysis is to provide a precise conclusion on the potential association between APOE ε2/ε3/ε4 polymorphisms and the risk of CAD in patients with T2DM based on case-control studies.

Methods: Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases were searched for all relevant studies prior to August 2017 in English and Chinese language. The pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were used to assess the strength of the relationships. The between-study heterogeneity was evaluated by Cochran's Q-test and the I² index to adopt fixed- or random- effect models.

Results: A total of 13 studies were eligible for inclusion. There was evidence for significant associations between APOE ε4 mutation and the risk of CAD in patients with T2DM (for ε3/ε4 vs. ε3/ε3: OR = 1.69, 95% CI = 1.38–2.08, P < 0.001; for ε4/ε4 vs. ε3/ε3: OR = 2.72, 95% CI = 1.61–4.60, P < 0.001; for ε4/ε4+ε3/ε4 vs. ε3/ε3: OR = 1.83, 95% CI = 1.52–2.22, P < 0.001; for ε4 allele vs. ε3 allele: OR = 1.64, 95% CI = 1.40–1.94, P < 0.001). In contrast, no significant associations were found in genetic model of APOE ε2 mutation (for ε2/ε2 vs. ε3/ε3: OR = 1.67, 95% CI = 0.90–3.09, P = 0.104; for ε2/ε3 vs. ε3/ε3: OR = 1.18, 95% CI = 0.93–1.51, P = 0.175; for ε2/ε2+ε2/ε3 vs. ε3/ε3: OR = 1.26, 95% CI = 0.88–1.82, P = 0.212; for ε2 allele vs. ε3 allele: OR = 1.34, 95% CI = 0.98–1.84, P = 0.07).

Conclusions: The APOE gene ε4 mutation is associated with an increased risk of CAD in patients with T2DM, while the ε2 variation has null association with this disease.

Apolipoprotein E polymorphisms are associated with ischemic stroke susceptibility in a Northwest China Han population

Ischemic stroke (IS), the leading neurology cause of death and disability worldwide, is influenced by gene polymorphisms. To explore the association between IS and Apolipoprotein E (APOE) gene polymorphisms, a case–control study containing 513 IS patients and 514 controls without IS was conducted in a Northwest China Han population. MassARRAY iPLEX system was applied to determine the APOE polymorphisms according to the alleles of two single nucleotide polymorphisms (SNPs) of APOE, rs429358, and rs7412. The results showed that rs429358 and rs7412 were in Hardy–Weinberg equilibrium (HWE) in both cases and controls groups. APOE ε4 allele, ε4/ε4 genotype, and ε4-containing genotypes were associated with IS. According to the results of Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification system, APOE ε2 allele, ε4 allele, and ε4/ε4 genotype were associated with large artery atherosclerosis IS subtypes. In addition, the results also indicated that the ε4 allele related to undetermined IS and ε4/ε4 genotype was related to small vessel disease IS. Compared with subjects with non-ε4-containing genotypes, the total cholesterol (TC) and low-density lipoprotein (LDL) level in blood and the proportion of cardiopath history were higher in all subjects with ε4-containing genotypes. Besides, the triacylglycerides (TG) level in blood was higher in controls with ε4-containing genotypes. In conclusion, in a Northwest China Han population, APOE ε4 allele was associated with blood lipid level. The TC and LDL levels were the independent risk factors for IS. APOE was a risk gene for IS, but not independent, especially for large artery atherosclerosis IS.

Association between apolipoprotein E polymorphisms and premature coronary artery disease: a meta-analysis

BACKGROUND

Although several studies have explored the genetic polymorphisms of apolipoprotein E (APOE) and their impact on premature coronary artery disease (PCAD), there is still some controversy regarding the significance of their association. Our aim is to estimate the association between APOE polymorphisms and PCAD via meta-analysis.

METHODS

All relevant case-control studies and cohort studies published in Chinese or English prior to March 2016 were searched for in electronic databases. Detailed information concerning each piece of literature was independently extracted by two researchers. We used STATA11.0 to process all data and to determine the pooled odds ratio (OR). Altogether, four genetic models were applied to calculate OR and 95% confidence interval (CI): (1) ε2 allele vs. ε3 allele; (2) ε2 carriers vs. ε3/3; (3) ε4 allele vs. ε3 allele; (4) ε4 carriers vs. ε3/3.

RESULTS

Eighteen studies concerning APOE polymorphisms and their impact on PCAD were included in the final analysis. The pooled analysis displayed that the ε2 allele and ε2 carriers increased the risk of PCAD significantly among Asians (OR 1.54; 95% CI, 1.09-2.17; OR 1.65; 1.10-2.47), while they showed protective effects on PCAD in Caucasians (OR 0.77; 95% CI, 0.62-0.95; OR 0.69; 0.54-0.89). Subjects with the ε4 allele and ε4 carriers showed significant associations with PCAD (OR 1.62; 95% CI, 1.27-2.06; OR 1.65; 1.27-2.15).

CONCLUSIONS

Our investigation supported the fact that the ε2 allele in APOE may appear as a risk factor for PCAD in Asians while a protective factor in Caucasians and that the ε4 allele acted as a genetic risk factor for PCAD.

Atherosclerotic and thrombotic genetic and environmental determinants in Egyptian coronary artery disease patients: a pilot study

BACKGROUND

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Multiple genetic variants in combination with various environmental risk factors have been implicated. This study aimed to investigate the association of twelve thrombotic and atherosclerotic gene variants in combination with other environmental risk factors with CAD risk in a preliminary sample of Egyptian CAD patients.

METHODS

Twenty three consecutive CAD patients undergoing diagnostic coronary angiography and 34 unrelated controls, have been enrolled in the study. Genotyping was based on polymerase chain reaction and reverse multiplex hybridization. Five genetic association models were tested. Data distribution and variance homogeneity have been checked by Shapiro-Wilk test and Levene test, respectively; then the appropriate comparison test was applied. Spearman's rank correlation coefficient was used for correlation analysis and logistic regression has been performed to adjust for significant risk factors. Clustering the study participants according to gene-gene and gene-environment interaction has been done by Detrended Correspondence Analysis (DCA).

RESULTS

The univariate analysis indicated that the five variants; rs1800595 (FVR2; factor 5), rs1801133 (MTHFR; 5,10-methylenetetrahydrofolate reductase), rs5918 (HPA-1; human platelet antigen 1), rs1799752 (ACE; angiotensin-converting enzyme), and rs7412 and rs429358 (ApoE; apolipoprotein E) were significantly associated with CAD susceptibility under different genetic models. Multivariate analysis revealed clustering of the study population into three patient groups (P) and one control group. FVR2 was the most variant associated with CAD patients, combined with the factor V Leiden (FVL) variant in P1 cluster and with both ACE and MTHFR 667C > T in P2. Whereas, P3 was mostly affected by both MTHFR 667C > T and FXIII (factor 13) V89L mutations. When combined with traditional risk factors, P1 was mostly affected by dyslipidemia, smoking and hypertension, while P2 was mostly affected by their fasting blood sugar levels and ApoE variant.

CONCLUSIONS

Taken together, these preliminary results could have predictive value to be applied in refining a risk profile for our CAD patients, in order to implement early preventive interventions including specific antithrombotic therapy. Further large scale and follow-up studies are highly recommended to confirm the study findings.

Apolipoprotein E Gene Variants and Risk of Coronary Heart Disease: A Meta-Analysis

Objectives. Apo E genes involved in lipoprotein synthesis and metabolism are considered one of the candidates to CHD. However, the results remain conflicting. Methods. We performed this meta-analysis based on 30 published studies including 11,804 CHD patients and 17,713 controls. Results. Compared with the wild genotype E3/3, the variant genotypes ApoEE3/4 and E4/4 were associated with 22% and 45% increased risk of CHD, respectively (E3/4 versus E3/3: OR = 1.22, 95% CI = 1.15–1.29; E4/4 versus E3/3: OR = 1.45, 95% CI = 1.23–1.71). Besides, compared with ε3 allele, carriers with the ε4 allele had a 46% increased risk of CHD (OR = 1.46, 95% CI = 1.28–1.66), while the ε2 had no significantly decreased risk of CHD. In the subgroup analysis by ethnicity, ε4 had a 25% increased risk of CHD in Caucasians (OR = 1.25, 95% CI = 1.11–1.41), and the effects were more evident in Mongolians (OR = 2.29, 95% CI = 1.89–2.77). The ε2 allele had a decreased risk of CHD in Caucasians (OR = 0.84, 95% CI = 0.74–0.96), but not in Mongolians. Conclusions. The analysis suggested that ApoEε4 mutation was associated with the increased risk of CHD, while ApoEε2 allele had a decreased risk of CHD just in Caucasians.

Apolipoprotein E levels and apolipoprotein E genotypes in incident cardiovascular disease risk in subjects of the Prevention of Renal and Vascular End-stage disease study

BACKGROUND

Apolipoprotein E (apoE) is a component of all major lipoprotein classes with multiple functions including clearance of circulating triglyceride-rich lipoprotein particles and hepatic production of triglyceride-rich lipoprotein, thus affording several avenues for apoE involvement in atherosclerosis development. ApoE has 3 isoforms (E2, E3, and E4) based on a common genetic polymorphism. Numerous studies have been performed assessing cardiovascular disease (CVD) risk relative to the 6 resulting genotypes; however, surprisingly, few studies have been performed assessing risk attributable to apoE plasma levels either alone or in addition also taking into account apoE genotypes.

OBJECTIVE

To examine the role of apoE levels together with apoE genotypes on incident CVD risk in a large population-based cohort and also to afford preliminary characterization of atherogenic apoE-containing lipoprotein particles.

METHODS

Cox multivariable proportional hazards modeling was performed on a cohort of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study as a function of apoE levels and apoE genotypes adjusted for age, gender, and past history of CVD. Further modeling was performed with single addition of clinical and biomarker parameters to elucidate the nature of apoE-associated risk.

RESULTS

High apoE levels were demonstrated to be associated with CVD risk (hazard ratio per apoE standard deviation, 1.20; 95% confidence interval, 1.11-1.31; P < .0001) both overall and within the high-frequency apoE genotype groups (ε2ε3, ε3ε3, and ε3ε4). Only on addition of apoB-containing lipoprotein parameters to models, did apoE levels lose association with risk.

CONCLUSIONS

ApoE levels positively associate with incident CVD risk with apoE-associated risk likely residing in apoB-containing lipoproteins.

Role of the Apolipoprotein E Polymorphisms in the Development of Retinal Vein Occlusion in a Tunisian Population: A Case–Control Study

Apolipoprotein E ( APOE) is a member of the apolipoprotein gene family. APOE is polymorphic with 3 main allelic types: ∊2, ∊3, and ∊4. Certain of these alleles have been associated with higher vascular risk. However, the association of APOE genotypes with retinal biomarkers and risk of retinal stroke is less clear. This study evaluated the role of APOE polymorphisms in retinal vein occlusion (RVO). In the present study, 2-point mutations coding amino acid residues 112 and 158 were amplified using the polymerase chain reaction (PCR) from DNA extracted from Tunisian participants. APOE genotypes were determined by multiplex PCR followed by molecular hybridization. Eighty-eight patients (26 women and 62 men) and 100 age- and gender-matched healthy participants were enrolled. The statistical study revealed a higher frequency of the ∊4 allele in patients as compared to controls (27.3% vs 9%) with a significant association of the ∊4 allele with the disease ( P < 10−3, Pa < 10−3, odds ratio [OR] = 3.8, 95% confidence interval [CI] = 2.1-6.8). The frequency of the ∊3 allele was significantly lower in the patients with RVO compared to the controls (60.2% vs 82.5%, respectively; P < 10−3, Pa < 10−3, OR = 0.32, 95% CI = 0.19-0.53). The ∊3 allele seems to be protective against the disease. There was no association between the APO ∊2 allele and RVO. The association of APOE allele and genotype with RVO requires further investigation in different populations.

Association between APOE polymorphism and metabolic syndrome in Uyghur ethnic men

OBJECTIVES

This study aimed to examine the association between apolipoprotein E (APOE) polymorphism and metabolic syndrome (MetS) among Uyghur ethnic men in Xinjiang, China.

PARTICIPANTS

A total of 482 patients with MetS and 510 healthy sex-matched and age-matched controls were recruited from the Xinjiang Uyghur Autonomous Region of China. The participants were subjected to routine physical and blood biochemical tests, and APOE genotyping was performed.

RESULTS

The APOE ε3/3 was the predominant type, with a frequency of 71.8%, while ε2/2 was less common than ε4/4 in Uyghur males. The frequencies of the APOE2, E3 and E4 alleles in Uyghur males were 8.5%, 80.0% and 11.5%, respectively. However, the distribution of APOE genotypes was significantly different between the MetS and control groups (p<0.001). In the MetS group, the frequencies of the ε2 and ε4 alleles and the frequencies of the ε2/2, ε2/3 and ε2/4 genotypes were significantly lower than those of the control group. Those individuals without the ε2 and ε4 alleles had higher MetS prevalence than the other gene carriers, and the ORs of these individuals developing MetS were 1.5 and 1.27 compared to the gene carriers. Triglyceride, serum total cholesterol and low-density lipoprotein cholesterol levels were lower and serum high-density lipoprotein was higher in the ε2 carriers than the ε3 carriers, and the prevalence of MetS, central obesity, high blood pressure, hypercholesterolaemia and hypertriglyceridaemia was lower in the APOE2 group than in the APOE4 group. The risks of these individuals with ε4 allele carriers getting these changes were 1.327, 1.780, 1.888, 1.428 and 2.571 times greater than those of ε2 allele carriers.

CONCLUSIONS

APOE4 is associated with many individual components of MetS, whereas APOE2 was associated with a reduced risk of MetS at the univariate level in Uyghur ethnic men.

Association of APOE polymorphisms with diabetes and cardiometabolic risk factors and the role of APOE genotypes in response to anti-diabetic therapy: results from the AIDHS/SDS on a South Asian population

BACKGROUND AND OBJECTIVES

Apolipoprotein E (APOE) gene polymorphisms have been examined extensively in multiple global populations particularly due to their crucial role in lipid metabolism and cardiovascular disease. However, the overall contribution of APOE polymorphisms in type 2 diabetes (T2D) and coronary artery disease (CAD) in South Asians is still under-investigated. The objectives of this investigation were: 1) to evaluate the distribution of APOE polymorphisms in a large diabetic case-control sample from South Asia, 2) to examine the impact of APOE polymorphisms on quantitative risk factors of T2D and CAD, and 3) to explore the contribution of APOE genotypes in the response to anti-diabetic therapy.

SUBJECTS AND METHODS

A total of 3564 individuals (1956 T2D cases and 1608 controls) used in this study were part of the Asian Indian Diabetic Heart Study/Sikh Diabetes Study (AIDHS/SDS). We assessed the association of APOE polymorphisms with T2D, CAD and cardiometabolic traits using logistic and linear regression analysis.

RESULTS AND CONCLUSIONS

No significant differences in the distribution of APOE genotypes were observed between T2D and CAD cases and controls. The APOE4 genotype carriers had moderately higher diastolic blood pressure (BP) (p=0.022), and lower HDL-cholesterol (p=0.026) compared to E4 non-carriers. Overall, the APOE genotype was not a significant predictor of cardiometabolic disease in this population. Further stratification of data from diabetic patients by APOE genotypes and anti-hyperglycemic agents revealed a significant (~23%) decrease in 2-hour glucose (p=0.004) and ~7% decrease in systolic BP (p<0.001) among APOE4 carriers compared to non-carriers on metformin and sulphonylurea (SU) combination therapy, and no such differences were seen in patients on other agents. Our preliminary findings point to the need for evaluating population-specific genetic variation and its interactions with therapeutic effects.

Relation between Apolipoprotein E Gene Polymorphism and Severity of Coronary Artery Disease in Acute Myocardial Infarction

Apolipoprotein E (ApoE) is a plasma protein and associated with cholesterol transport system. In several studies, the relationship between ApoE gene polymorphism and severity of coronary artery disease (CAD) has been shown. However, the relationship between ApoE gene polymorphism and severity of CAD in patients with acute myocardial infarction (MI) has not been well known. The aim of this study is to investigate the relation between ApoE polymorphism and severity of CAD in patients with acute MI by using the Gensini Score. In this study, 138 patients were admitted to cardiology clinic with diagnosis of acute MI, and angiographic assessment was performed using the Gensini Score. Blood samples were obtained from all patients in the first day. The patients with ApoE34 genotype had high Gensini scores. Besides, the patients with E4 allele carriers were associated with high Gensini score compared with the patients without E4 allele carriers (p:0,22). The patients with E4 allele carriers were associated with higher LDL cholesterol and total cholesterol compared with the patients without E4 allele carriers (p:0,001 and p:0,03, resp.). There were no statistically significant differences between ApoE genotypes and severity of CAD by using the Gensini Score. But, the patients with E4 allele carriers were associated with high lipid levels.

Association of MYOC and APOE promoter polymorphisms and primary open-angle glaucoma: a meta-analysis

BACKGROUND

Primary open-angle glaucoma (POAG) is the most common form of glaucoma with a genetic predisposition. The relationship between polymorphisms in MYOC or APOE promoter region and POAG has been addressed in many case-control studies, but the published results were not consistent.

METHODS

A meta-analysis assessing the association between five single nucleotide polymorphisms (SNPs) (in MYOC promoter: rs12035719 and rs2075648; in APOE promoter: rs405509, rs769446 and rs449647) and the risk of POAG was performed based on included studies from literature research. In fixed effect model or random effect model, the Mantel-Haenszel (M-H) pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to evaluate the genetic association. Stratification analysis was also conducted to test the association within Asian or Caucasian populations.

RESULTS

Twenty five case-control studies within multiple populations were identified and no publish bias was observed. Significant association was detected between POAG risk and MYOC rs2075648 in Caucasian (GA+AA vs. GG, OR=0.587, 95% CI=0.437-0.788, P < 0.001). For other SNPs and in other ethnic populations, no statistic evidence was detected for significant association between them and the development of POAG.

CONCLUSIONS

This meta-analysis suggested a genetic association between one of MYOC polymorphism (rs2075648) and the risk of POAG only in Caucasian population. The significant heterogeneity for this locus might imply the different POAG genetic basis among different populations.

CLU rs2279590 polymorphism contributes to Alzheimer's disease susceptibility in Caucasian and Asian populations

It is reported that CLU rs2279590 polymorphism is significantly associated with Alzheimer's disease (AD) in European ancestry. Recent studies investigated rs2279590 polymorphism in Asian population (Chinese, Japanese and Korean). Four studies showed negative association and two studies showed weak association between rs2279590 and AD. We believe that the weak association or no association may be caused by the relatively small sample size in Asian population. Here, we reinvestigated the association in Asian population. Meanwhile, to investigate the genetic heterogeneity of the rs2279590 polymorphism in Asian and Caucasian populations, we searched the PubMed and AlzGene databases and selected 11 independent studies (6 studies in Asian population and 5 studies in Caucasian population) including 20,655 individuals (8,605 cases and 12,050 controls) for meta-analysis. Our results showed significant association between rs2279590 polymorphism and AD in Asian population with P = 2.00E-04 and P = 2.00E-04 using additive and recessive models, respectively. We observed no significant heterogeneity between Asian and Caucasian populations. We believe that our results may be helpful to understand the mechanisms of CLU in AD pathogenesis and will be useful for future genetic studies in AD.