Apolipoprotein E polymorphism and its relation to plasma lipids in coronary heart disease

Association of Apolipoprotein E Gene Polymorphism with Lipid Profile and Ischemic Stroke Risk in Type 2 Diabetes Mellitus Patients

Background

Altered lipid profiles have consistently been linked to cerebrovascular events. Ischemic stroke (IS) was a common comorbid condition established in type 2 diabetes mellitus (T2DM). The apolipoprotein E (ApoE) gene which has a notably critical function in lipoprotein metabolism is believed as one of the potential candidate genes susceptible to IS complications in T2DM. This research aimed to determine the association of apolipoprotein E gene polymorphism with lipid profile and IS risk in T2DM patients.

Methods

This case-control study involved a total of 60 diabetic participants divided into two groups with and without IS. ApoE was genotyped using PCR and sequencing analysis.

Results

The most predominant genotype observed in 27 participants (45%) was E3/E3. Lower levels of high-density lipoprotein cholesterol (HDL-C) were found in ε2 carriers (p=0.003; 95% CI -23.35--4.89) and ε4 carriers (p=0.019; 95% CI 1.38-14.55) compared to ε3 homozygotes. Total cholesterol (TC), triglyceride, and low-density lipoprotein cholesterol (LDL-C) levels had no association with ApoE gene polymorphism in this study. ApoE gene polymorphism was not related to IS in T2DM (p=0.06; adjusted OR: 4.71; 95% CI 0.93-23.79).

Conclusions

ApoE ε2 and ε4 carriers were associated with lower levels of HDL-C. No association was identified between ApoE gene polymorphism and IS in T2DM patients.

Association of Apolipoprotein E Gene Polymorphism with Ischemic Stroke in Coronary Heart Disease Patients Treated with Medium-intensity Statins

OBJECTIVE

To study the association of apolipoprotein E(APOE) gene polymorphism with ischemic stroke (IS) in coronary heart disease (CHD) patients treated with medium-intensity statins.

METHODS

The retrospective study was performed on 662 samples including 169 CHD subjects complicated with IS, 296 subjects with CHD, and 197 control subjects. The APOE gene was obtained from case files. Univariable and multivariable logistic regression analyses were utilized to recognize the possible risks of CHD and IS.

RESULTS

The frequency of ε3-ε4 genotype was increased in the CHD group (p=0.013) and CHD-IS group (p=0.001), the frequency of ε4 allele was also increased in the CHD group (p=0.047) and the CHD-IS group (p=0.009) compared with control group. ε3-ε4 genotype was the independent risk for CHD and CHD-IS after adjusting for traditional risk factors with adjusted odds ratio (AOR) 2.210, 95%CI: 1.263-3.867, p=0.005) and (AOR 2.794, 95%CI: 1.539-5.072, p=0.002). The ε4 allele was also significantly associated with CHD (AOR 2.126, 95%CI: 1.265-3.575,=0.004) and CHD-IS (AOR 2.740, 95%CI: 1.569-4.784, p=0.001).

CONCLUSION

These results demonstrated that ε4 allele influenced the development of CHD with or without IS, especially for the genotype of ε3-ε4. CHD patients carrying the ε3-ε4 genotype and the ε4 allele were significantly associated with the incidence of IS, even if medium-intensity statins had been used.

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.

Meta-analysis for the Association of Apolipoprotein E ε2/ε3/ε4 Polymorphism with Coronary Heart Disease

BACKGROUND

Coronary heart disease (CHD) is a multifactorial disease and is thought to have a polygenic basis. Apolipoprotein E (APOE) gene is one such candidate with its common ε2/ε3/ε4 polymorphism in CHD. In recent years, numerous case-control studies have investigated the relationship of APOE polymorphism with CHD risk. However, the results are confusing.

METHODS

To clarify this point, we undertook a meta-analysis based on 14 published studies including 5746 CHD cases and 19,120 controls. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were assessed for association using a random-effects or fixed-effects model using STATA version 10 (StataCorp LP, College Station, TX, USA).

RESULTS

Overall, the analysis showed that carriers of APOE ε2 allele decreased risk for CHD (ε2 allele vs. ε3 allele: OR = 0.82, 95% CI: 0.75-0.90, P < 0.001; ε2 carriers vs. ε3 carriers: OR = 0.81, 95% CI: 0.73-0.89, P < 0.001), compared with those carrying ε3 allele, especially in Caucasian population. However, those with ε4 allele had a significant increased risk for CHD (ε4 allele vs. ε3 allele: OR = 1.34, 95% CI: 1.15-1.57, P < 0.001), especially in Mongoloid population. Potential publication bias was observed in the genetic model of ε4 versus ε3, but the results might not be affected deeply by the publication bias. When we accounted for publication bias using the trim and fill method, the results were not materially alerted, suggesting the stability of our results.

CONCLUSIONS

Taken together, our meta-analysis supported a genetic association between APOE gene and CHD. ε4 increased the risk of CHD, whereas ε2 decreased the risk of CHD.

Apolipoprotein E gene polymorphism and risk of type 2 diabetes and cardiovascular disease

BACKGROUND

Lipoprotein-related mechanisms have been associated with damage to the cardiovascular system in diabetic patients. Apolipoprotein E gene which affects the clearance of lipoproteins and consequently the lipid profile in our body is one of the most studied candidate genes and recently has been reported to be associated with T2DM and CAD. In this work, we studied the association of apoE gene polymorphism with T2DM and CVD and its effect on plasma lipids profile.

METHODS

Our study was conducted on 284 subjects categorized into 100 patients with T2DM, 100 patients with T2DM complicated with CVD and 84 normal control subjects. ApoE gene polymorphism was genotyped by real-time PCR using TaqMan(®) SNP Genotyping Assay.

RESULTS

ApoE E3/E3 genotype was the most common in our subjects. The frequencies of E3/E4 genotype and ε4 allele were increased in both T2DM patients and CVD patients as compared with controls, but were significant only in CVD patients (p = 0.004 and 0.007, respectively). Diabetic patients who carried E3/E4 genotype were at 2.4-fold increased risk to develop CVD (95 % CI 1.14-5.19, P = 0.02) and the ε4 allele associated with 2.23-fold higher CVD risk (95 % CI 1.09-4.59, P = 0.02). After adjustment for other established risk factors, E3/E4 genotype was an independent risk factor for CVD (OR = 2.3, p = 0.009) but not for T2DM (OR = 1.7, p = 0.28), while ε4 allele was an independent risk factor for both T2DM (OR = 2.2, p = 0.04) and CVD (OR = 3.0, p = 0.018) with 5.9-fold increased risk to develop CVD in T2DM patients (p = 0.019). E3/E4 genotype associated with significantly higher levels of TC and non HDL-C in all groups and with significantly higher levels of LDL-C in both T2DM and CVD patients.

CONCLUSIONS

ApoE gene polymorphisms associate with CVD and affect the lipid profile. The ε4 allele is an independent risk factor for both T2DM and CVD. Further genetic studies to add information beyond the traditional cardiovascular risk factors in T2DM and to identify risk genotypes will help in early prediction and identification of at risk patients.

Association between Apolipoprotein E polymorphism and myocardial infarction risk: A systematic review and meta-analysis

Published data regarding the association between Apolipoprotein E (ApoE) genetic variation and myocardial infarction (MI) risk were not always consistent. Therefore, the current meta-analysis was conducted to derive a more precise estimation of the association between ApoE polymorphism and MI risk. PubMed and Web of Science were searched to identify relevant studies. Summary odds ratio (ORs) and 95% confidence intervals (CIs) were calculated using random-effect or fixed-effect models based on the heterogeneity of included studies. All the tests were performed using Stata 11.0. A total of 22 eligible studies were identified in this meta-analysis. The results show that ApoE ε2 and ε4 alleles were associated with MI risk. The study suggests that there is close association between ApoE polymorphism and MI risk. It shows that ApoE ε2 allele is a protective factor of MI, while ε4 allele is a risk factor of MI, especially in Caucasian and Asian population. Nevertheless, well-designed, unbiased and larger sample size studies are required to confirm the results.

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 apolipoprotein E (ApoE) polymorphisms with risk of primary hyperuricemia in Uygur men, Xinjiang, China

BACKGROUND

Apolipoprotein E (ApoE) participates in lipoprotein metabolism and immune regulation. This study assessed association between ApoE polymorphisms with hyperuricemia and uric acid metabolism in Uygur men, Xinjiang, China.

METHODS

A total of 474 hyperuricemia patients and 518 healthy male controls were recruited from the Health Screening Center, Uygur region of Xinjiang, China and subjected to ApoE genotyping using a multiplex amplification refractory mutation system PCR.

RESULTS

Apolipoprotein E3/3 genotype was the predominant type with a frequency of 67.7%, while E2/2 was lower than E4/4 in Uygur males. The frequencies of ApoE2, E3, and E4 alleles were 8.5%, 80.1% and 11.4%, respectively. Distribution of ApoE genotypes was significantly different in hyperuricemia patients from the healthy controls (p<0.001). Particularly, the frequency of ApoE E3/3 was 71.7%, E2/3 9.3%, E3/4 9.3%, E4/4 3.2%, E2/4 2.3%, and E2/2 0.2% in patients vs. 68.1%, 4.6%, 2.9%, 12%, 0.6%, and 4.6% in controls, respectively. Moreover, frequency of ApoE E2 allele was greater in the healthy controls than in patients (p<0.001) and the highest level of uric acid occurred in those with ApoE2/4 and E3/4 genotypes, whereas the lowest uric acid level occurred in those with ApoE E2/2 genotype. In addition, the subjects with the ApoE2 allele had a lower uric acid and LDL-C level than those with the ApoE3 allele and ApoE4 allele (p<0.05). The risk of developing hyperuricemia in subjects without the ApoE2 allele was 1.7 fold higher than those subjects with the ApoE2 allele.

CONCLUSIONS

This study revealed frequencies and distributions of ApoE alleles and genotypes in Uygur males, which are different from Han Chinese. ApoE E4 was associated with a slightly higher risk of primary hyperuricemia, whereas ApoE E2 was associated with reduced risk of primary hyperuricemia and LDL-C level.

Apolipoprotein e gene polymorphism and its effect on plasma lipids in arteriosclerosis

BACKGROUND & OBJECTIVES

Myocardial infarction and stroke are leading causes of death worldwide. Primarily, arteriosclerosis is responsible for these events. There is a strong family history suggesting a genetic cause. Apolipoprotein E (apo E) plays an important role in lipid metabolism. Apo E is polymorphic with three isoforms, ApoE2, ApoE3 and ApoE4; which translate into three alleles of the gene. Its polymorphism may be a risk determinant of atherosclerosis.

METHODS

Lipoprotein concentrations were studied, in 100 myocardial infarction and 50 cerebrovascular stroke subjects and compared with age and sex matched controls. Genotypes for apo E isoforms (E2, E3, and E4) for all above subjects and age and sex matched controls were determined by Multiplex Amplification Refractory Mutation System PCR.

RESULTS

There were statistically significant higher values of serum total cholesterol and LDL cholesterol in study group, as compared to control group. Study of Apo E isoforms revealed higher proportion of E4 allele in the study group as compared to control group. The occurrence of each allele frequency in study and control group was E4E4: 28.66% and 16.0%, E3E3: 39.33% and 56.66%, E4E3: 14.66% and 9.33%, E3E2: 8.66% and 10.66%, E4E2: 4.66% and 2.66% & for E2E2: 4.0% and 4.66% respectively.

INTERPRETATION & CONCLUSION

There were significantly higher levels of serum total cholesterol, LDL cholesterol and triglyceride with E4 allele; when compared with in the study group and between study group and control group. Apo E polymorphism influences serum lipid levels and is an independent risk determinant of arteriosclerosis.

Association between apolipoprotein E gene polymorphism and myocardial infarction

We investigated apolipoprotein E (APOE) genotypic influence on myocardial infarction risk in South India, where the disease is emerging as a major threat to the public health care system. The study included 412 subjects: 202 myocardial infarction patients and 210 age- and sex-matched controls. DNA was isolated, the polymorphism of the APOE gene was subjected to PCR, and lipid levels were evaluated. The prevalence of E3/E4 genotypes in patients (18.3%) was 1.5-fold that of controls (11.0%, p < 0.05), and the prevalence of E2/E3 genotypes was higher in controls (6.7%) than in patients (4%). The ε4 allele was significantly associated with myocardial infarction: χ(2) = 12.4; OR 2.2 (CI 95%: 1.4-3.4), p < 0.004, for ε4 versus ε3 and χ(2) = 5.7; OR 2.7 (CI 95%: 1.1-6.5), p > 0.01, for ε4 versus ε2. A significant association of the ε4 allele, especially the E3/E4 genotype, with myocardial infarction was observed.

Apolipoprotein E gene polymorphism: effects on plasma lipids and risk of type 2 diabetes and coronary artery disease

BACKGROUND

The most common apolipoprotein E (apoE) gene polymorphism has been found to influence plasma lipid concentration and its correlation with coronary artery disease (CAD) has been extensively investigated in the last decade. It is, however, unclear whether apoE gene polymorphism is also associated with increased risk of type 2 diabetes mellitus (T2DM). The knowledge of this study may provide the primary prevention for T2DM and CAD development before its initiation and progression. Therefore, this study was carried out to determine the association between apoE gene polymorphism and T2DM with and without CAD and its role in lipid metabolism.

METHODS

The case-control study was carried out on a total of 451 samples including 149 normal control subjects, 155 subjects with T2DM, and 147 subjects with T2DM complicated with CAD. The apoE gene polymorphism was tested by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Univariable and multivariable logistic regression analyses were used to identify the possible risks of T2DM and CAD.

RESULTS

A significantly increased frequency of E3/E4 genotype was observed only in T2DM with CAD group (p = 0.0004), whereas the ε4 allele was significantly higher in both T2DM (p = 0.047) and T2DM with CAD (p = 0.009) as compared with controls. E3/E4 genotype was also the independent risk in developing CAD after adjusting with established risk factors with adjusted odds ratio (OR) 2.52 (95%CI 1.28-4.97, p = 0.008). The independent predictor of individuals carrying ε4 allele still remained significantly associated with both CAD (adjusted OR 2.32, 95%CI 1.17-4.61, p = 0.016) and T2DM (adjusted OR 2.04, 95%CI 1.07-3.86, p = 0.029). After simultaneously examining the joint association of E3/E4 genotype combined with either obesity or smoking the risk increased to approximately 5-fold in T2DM (adjusted OR 4.93, 95%CI 1.74-13.98, p = 0.003) and 10-fold in CAD (adjusted OR 10.48, 95%CI 3.56-30.79, p < 0.0001). The association between apoE genotypes on plasma lipid levels was compared between E3/E3 as a reference and E4-bearing genotypes. E4-bearing genotypes showed lower HDL-C and higher VLDL-C and TG, whereas other values of plasma lipid concentrations showed no significant difference.

CONCLUSIONS

These results indicate that ε4 allele has influence on lipid profiles and is associated with the development of both T2DM with and without CAD, and furthermore, it increased the risk among the subjects with obesity and/or smoking, the conditions associated with high oxidative stress.

Apolipoprotein E gene polymorphism and dyslipidaemia in adult Asian Indians: A population based study from Calcutta, India

AIM:

The study was aimed to determine the association of Apolipoprotein E (apo E) gene polymorphisms on lipid levels in Asian Indian population.

METHODS:

A total of 350 (184 males and 166 females) adult (30 years and above) Asian Indians of Calcutta and suburb participated in the study. Anthropometric measures, lipids profiles, and blood glucose measures were collected. Out of 350 subjects, a sample of 70 individuals was selected randomly for genotyping after adjusting for age and sex. The apo E gene polymorphisms were determined by agarose gel electrophoresis.

RESULTS:

The apo E polymorphism showed significant association with dyslipidaemia (P=0.0135) with ε3/4 combination has had the highest occurrence of dyslipidaemia and metabolic syndrome (MS) followed by ε4/4 <ε3/3 <ε2/4 <ε2/3 in decreasing order.

CONCLUSIONS:

The ε4 allele of apo E gene independent of other risk factors is associated with dyslipidaemia in particular with low HDLc and high TC: HDLc ratio.

Requirements for Vitamin D Across the Life Span

Adequate provision of vitamin D has been found, in ecological, cross-sectional, and observational studies, to be associated with reduction in the risk of many types of cancer, cardiovascular diseases (CVDs), autoimmune diseases, diabetes mellitus types 1 and 2, neurological disorders, several bacterial and viral infections, and adverse pregnancy outcomes in addition to the classical bone disorders of rickets and osteomalacia. Furthermore, investigators have found adequate repletion and increased intakes of vitamin D to be associated with reduced all-cause mortality rates. These findings have been supported by the limited number of properly conducted randomized controlled trials (RCTs) that used more than 400 IU/day of vitamin D. This review presents an overview of the role of vitamin D for the promotion of health for the more important vitamin D-related diseases and conditions. Serum 25-hydroxyvitamin D concentrations of 30—60 ng/ml, corresponding to oral intake or skin production of 1,000—4,000 IU/day of vitamin D, appear necessary in adults for avoidance of hypovitaminosis D-related ill health. People of all ages are encouraged to obtain more vitamin D from judicious exposure to sunshine (for ultraviolet B [UVB] irradiation) or from regular vitamin D supplements because dietary sources do not provide sufficient vitamin D to prevent any health risks other than those of rickets and osteomalacia.

Cholesterol ester transfer protein and apolipoprotein E gene polymorphisms in hyperlipidemic Asian Indians in North India

We determined the distribution of the polymorphic variants of CETP TaqIB and ApoE genes and their association with lipid and anthropometric parameters in hyperlipidemic and normolipidemic Asian Indians in North India. CETP TaqIB and ApoE polymorphism were assayed by PCR-RFLP in hyperlipidemic (n = 220) and normolipidemic (n = 367) subjects. Plasma lipids levels were estimated using commercially available kits from Randox (USA). The distribution of CETP TaqIB genotypes and alleles did not differ between the two groups. The frequency of ApoE ε4 allele was significantly higher in hyperlipidemic than normolipidemic subjects. Serum lipid levels were comparable between subjects with the different CETP TaqIB and ApoE genotypes in the two groups. Multivariate analysis after adjusting for age, sex, BMI, WHR, and total skinfold thickness showed that subjects with the Ε3Ε4 genotype and ε4 allele carriers were at significantly higher odds to develop hyperlipidemia [2.07 (1.29-3.30) and 2.05 (1.30-3.24), respectively] as compared to the other genotypes. ApoE ε4 allele and E3E4 genotype emerged as important genetic markers for hyperlipidemia in this study population.

Vascular pathology in the aged human brain

Cerebral atherosclerosis (AS), small vessel disease (SVD), and cerebral amyloid angiopathy (CAA) are the most prevalent arterial disorders in the aged brain. Pathogenetically, AS and SVD share similar mechanisms: plasma protein leakage into the vessel wall, accumulation of lipid-containing macrophages, and fibrosis of the vessel wall. CAA, on the other hand, is characterized by the deposition of the amyloid β-protein in the vessel wall. Despite these differences between CAA, AS and SVD, apolipoprotein E (apoE) is involved in all three disorders. Such a pathogenetic link may explain the correlations between AS, SVD, CAA, and Alzheimer’s disease in the brains of elderly individuals reported in the literature. In addition, AS, SVD, and CAA can lead to tissue lesions such as hemorrhage and infarction. Moreover, intracerebral SVD leads to plasma protein leakage into the damaged vessel wall and into the perivascular space resulting in a blood–brain barrier (BBB) dysfunction. This SVD-related BBB dysfunction is considered to cause white matter lesions (WMLs) and lacunar infarcts. In this review, we demonstrate the relationship between AS, SVD, and CAA as well as their contribution to the development of vascular tissue lesions and we emphasize an important role for apoE in the pathogenesis of vessel disorders and vascular tissue lesions as well as for BBB dysfunction on WML and lacunar infarct development.