Apolipoprotein E polymorphism in men and women from a Spanish population: allele frequencies and influence on plasma lipids and apolipoproteins

Polygenic Propensity for Longevity, APOE-ε4 Status, Dementia Diagnosis, and Risk for Cause-Specific Mortality: A Large Population-Based Longitudinal Study of Older Adults

To deepen the understanding of genetic mechanisms influencing mortality risk, we investigated the impact of genetic predisposition to longevity and APOE-ε4, on all-cause mortality and specific causes of mortality. We further investigated the mediating effects of dementia on these relationships. Using data on 7 131 adults aged ≥50 years (mean = 64.7 years, standard deviation [SD] = 9.5) from the English Longitudinal Study of Aging, genetic predisposition to longevity was calculated using the polygenic score approach (PGSlongevity). APOE-ε4 status was defined according to the absence or presence of ε4 alleles. The causes of death were ascertained from the National Health Service central register, which was classified into cardiovascular diseases, cancers, respiratory illness, and all other causes of mortality. Of the entire sample, 1 234 (17.3%) died during an average 10-year follow-up. One-SD increase in PGSlongevity was associated with a reduced risk for all-cause mortality (hazard ratio [HR] = 0.93, 95% confidence interval [CI]: 0.88-0.98, p = .010) and mortalities due to other causes (HR = 0.81, 95% CI: 0.71-0.93, p = .002) in the following 10 years. In gender-stratified analyses, APOE-ε4 status was associated with a reduced risk for all-cause mortality and mortalities related to cancers in women. Mediation analyses estimated that the percent excess risk of APOE-ε4 on other causes of mortality risk explained by the dementia diagnosis was 24%, which increased to 34% when the sample was restricted to adults who were aged ≤75 years old. To reduce the mortality rate in adults who are aged ≥50 years old, it is essential to prevent dementia onset in the general population.

Sex Differences in Cognition Across Aging

Sex and gender differences are seen in cognitive disturbances in a variety of neurological and psychiatry diseases. Men are more likely to have cognitive symptoms in schizophrenia whereas women are more likely to have more severe cognitive symptoms with major depressive disorder and Alzheimer's disease. Thus, it is important to understand sex and gender differences in underlying cognitive abilities with and without disease. Sex differences are noted in performance across various cognitive domains - with males typically outperforming females in spatial tasks and females typically outperforming males in verbal tasks. Furthermore, there are striking sex differences in brain networks that are activated during cognitive tasks and in learning strategies. Although rarely studied, there are also sex differences in the trajectory of cognitive aging. It is important to pay attention to these sex differences as they inform researchers of potential differences in resilience to age-related cognitive decline and underlying mechanisms for both healthy and pathological cognitive aging, depending on sex. We review literature on the progressive neurodegenerative disorder, Alzheimer's disease, as an example of pathological cognitive aging in which human females show greater lifetime risk, neuropathology, and cognitive impairment, compared to human males. Not surprisingly, the relationships between sex and cognition, cognitive aging, and Alzheimer's disease are nuanced and multifaceted. As such, this chapter will end with a discussion of lifestyle factors, like education and diet, as modifiable factors that can alter cognitive aging by sex. Understanding how cognition changes across age and contributing factors, like sex differences, will be essential to improving care for older adults.

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.

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

BACKGROUND

The role of apolipoprotein E gene (APOE) in lipid metabolism has been well established, and APOE is associated with the risk of cardiovascular disease (CVD) and diabetes mellitus (DM). However, the relationship between APOE polymorphisms and type 2 diabetes (T2DM) with or without CVD remains unclear.

METHODS

In this cross-sectional study, a total of 924 participants including 211 controls (CVD-T2DM-), 247 T2DM patients with CVD (CVD-T2DM+), 232 CVD patients without T2DM (CVD + T2DM-) and 234 T2DM patients with CVD (CVD + T2DM+), were genotyped using chip platform. The association between APOE polymorphisms and T2DM patients with or without CVD was analyzed by univariable and multivariable logistic analysis.

RESULTS

The present study showed that the frequency of E3/E4 increased in T2DM patients with CVD (p < 0.01). The ε4 allele was higher in CVD patients without T2DM (p < 0.01) and T2DM patients with CVD (p < 0.01) as compared with the controls.

CONCLUSIONS

The subjects carrying ε4 allele have increased risk of CVD and T2DM, and exhibit higher level of lipid profiles.

Association of APOE and CETP TaqIB Polymorphisms with Type 2 Diabetes Mellitus

Apolipoprotein E (APOE) and cholesteryl ester transfer protein (CETP) play an important role in the lipid metabolism. Dyslipidemia is one of the complications that found in type 2 diabetes mellitus (T2DM) patients. The aim of this study was to investigate the association of APOE and CETP TaqIB polymorphisms with T2DM and its related metabolic parameters in Southern Thai population. Study subjects were 241 T2DM patients and 275 healthy controls. The APOE and CETP TaqIB polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. APOE polymorphism showed a statistical difference in allele frequencies (p = 0.025) and genotype distributions (p <0.001) between T2DM patients and healthy controls. The E4 carriers were associated with a significantly higher TC, and/or LDL-C levels compared to the E2 and E3 carriers, respectively in all subjects and healthy controls. Moreover, CETP TaqIB B2B2 genotype was significantly higher HDL-C levels compared with B1B1, and B1B2 genotypes in all subjects, and T2DM patients. Multiple logistic regression analysis showed that APOE and CETP TaqIB polymorphisms were not associated with T2DM. In conclusion, APOE and CETP TaqIB polymorphisms might not be the genetic risk factors for T2DM in Southern Thai population, however, APOE and CETP TaqIB polymorphisms were associated with serum lipids in healthy controls and T2DM, respectively.

Association of ApoE Genetic Polymorphism and Type 2 Diabetes with Cognition in Non-Demented Aging Chinese Adults: A Community Based Cross-Sectional Study

Apolipoprotein E (ApoE) gene polymorphism has been implicated in predisposition to diabetes and dementia in old population, but the results from the different studies were inconclusive. A cross-sectional study was carried out to explore the relationship among ApoE gene polymorphism, diabetes and cognition in non-demented aging Chinese adults. A total number of 1000 community dwellers aged 55 years and above were randomly recruited. Demographic information of the participants was collected using well designed self-administered questionnaires. The Montreal Cognitive Assessment (MoCA) test was employed to evaluate the cognitive status of the participants. Semi-quantitative food frequency questionnaire was used to obtain the dietary intake information. Fasting venous blood samples were taken for ApoE genotyping and serum lipid measurements. 238 participants were type 2 diabetes mellitus (T2DM) patients and 145 participants were ApoE4 carriers. ApoE 4-T2DM subjects had higher serum triglyceride (TG) concentration than E2 and E3 carriers (P < 0.05). T2DM subjects carrying ApoE4 had lower cognition than subjects with E2 or E3 carriers (P < 0.05). Comparing to non-type 2 diabetic mild cognitive impaired (nT2DM-MCI) subjects, the type 2 diabetic mild cognitive impaired (T2DM-MCI) subjects have higher serum glucose (Glu) level and lower high-density lipoprotein (HDL-C) level (P < 0.05). The T2DM-MCI subjects carrying ApoE4 have lower cognition than E2 and E3 carriers (P <0.05); and the interaction of ApoE genotype with T2DM was detected (P < 0.05). Our results indicated the association among ApoE gene polymorphism, T2DM and cognitive performance in non-demented aging population. The carrying of ApoE4 predisposed the T2DM subjects and the T2DM-MCI subjects to have poor cognitive performance. Additional experimental studies are required to explore the mechanism that ApoE genotype modifies the risk for cognitive impairment in aging subjects with T2DM.

ApoE rs429358 and rs7412 Polymorphism and Gender Differences of Serum Lipid Profile and Cognition in Aging Chinese Population

ApoE gene polymorphism has been reportedly associated with serum lipids and cognition. However, very few studies have explored the combined effects of ApoE gene polymorphism and gender on serum lipid profile with subsequent impacts on cognition in Chinese population. A total of 1,000 Chinese community dwellers aged 55 years and above were recruited in this cross-sectional study. Demographic information of the participants was collected using well designed self-administered questionnaires. The Montreal Cognitive Assessment (MoCA) test was employed to evaluate the cognitive status of the participants. Semi-quantitative food frequency questionnaire (FFQ) was used to obtain the dietary intake information. Fasting venous blood samples were taken for ApoE genotyping and serum lipid measurements. Significant gender differences in cognition, serum lipid profile and dietary fat-rich foods consumption were observed (p < 0.05). Cognition of the subjects was found to be associated with ApoE genotypes (p < 0.05). ApoE rs429358 and rs7412 variants demonstrated a significant effect on cognitive performance in the male subjects; especially within the attention and language cognitive domains as well as the total MoCA score (p < 0.05), respectively. Serum lipid profile and cognition of Chinese adults are significantly linked with gender and ApoE genetic polymorphism. The ApoE variant rs429358 is found to be notably associated with cognition in aging male Chinese population.

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.

No change of the lipid profile under the control of ApoE gene polymorphism in schizophrenics under paliperidone treatment

The present study tried to explore the effects of Paliperidone on the lipid profiles of schizophrenia patients. One hundred twenty-nine subjects diagnosed with schizophrenia were enrolled into this study and completed the lipid profile evaluation. Their blood samples were obtained on the morning following a 12-hours fast. Cholesterol and triglyceride (TG) levels in plasma were determined, and lipoproteins were determined by enzymatic methods. All participants provided written informed consent, and underwent additional venous blood withdrawal for DNA extraction for genetic study of the ApoE gene polymorphism. Under T test, TC, TG and HDL levels all declined after Paliperidone treatment although with no statistically significant difference. The ratios of TC/HDL declined after Paliperidone treatment, but without statistically significant difference. After GEE-I analysis, we found that ApoE4 genotype (β = 34.471; p < 0.001) had a positive effect on the total cholesterol (TC) level; female had positive effect on the high-density lipoprotein (HDL) level (β = 15.361; p = 0.003); and age had a positive effect on the TG level (β = 1.317; p = 0.030). Smoking (β = 0.961; p = 0.016) had a positive effect on the ratio of TC/HDL change. Lipid profiles were not increased after Paliperidone treatment under the control of ApoE gene polymorphism.

Association between Apolipoprotein E Polymorphism and Chronic Kidney Disease in the Korean General Population: Dong-gu Study

Background

Few studies have investigated the association between Apolipoprotein E (APOE) polymorphisms and chronic kidney disease (CKD) in the general population, and their results are inconsistent.

Methods

The current study population was composed of 9,033 subjects aged ≥ 50 years who participated in the baseline survey of the Dong-gu Study, which was conducted in Korea between 2007 and 2010. APOE polymorphisms were identified by polymerase chain reaction, and the estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease equation.

Results

Individuals with the APOE E2 allele had significantly lower total and low density lipoprotein cholesterol levels, those with the APOE E4 allele had lower high density lipoprotein (HDL) cholesterol levels, and those with the APOE E3 allele had lower log-triglyceride levels. Adjusting for covariates (sex, age, body mass index, smoking, systolic blood pressure, hypertension, diabetes, total cholesterol, HDL cholesterol, log-transformed triglycerides, and log-transformed albumin to creatinine ratio), mean eGFR was not significantly different among APOE alleles (E2, 69.4 mL/min/1.73 m²; E3, 69.5 mL/min/1.73 m²; E4, 69.4 ml/min/1.73 m²; P = 0.873). Additionally, the odds ratios (ORs) indicated that APOE polymorphisms were not independent risk factors for CKD (OR, 1.07; 95% confidence interval [CI], 0.91 to 1.26 for the E2 vs. E3 allele; OR, 1.01; 95% CI, 0.88 to 1.16 for the E4 vs. E3 allele).

Conclusion

APOE polymorphisms were not associated with either eGFR or CKD in the general Korean population.

New insights into the distribution of APOE polymorphism in the Iberian Peninsula. The case of Andalusia (Spain)

BACKGROUND

The APOE gene has received much attention due to the remarkable spatial variation patterns of some of its genotypes and alleles in human populations and to its relevance in biomedicine.

AIM

This work was addressed to investigate the extent of APOE polymorphism between autochthonous Andalusians originating from Huelva and Granada provinces. No data on this marker in these southern Spanish coastal populations are available up to date.

SUBJECTS AND METHODS

This study used genomic DNA from healthy, unrelated Andalusians of both sexes (n = 322). All samples were genotyped for two SNPs, rs429358 and rs7412, which determine the three APOE alleles: ε2, ε3 and ε4. For analyses, a TaqMan-based technique was applied using a RT-PCR. Comparisons with other Mediterranean populations were performed based on multivariate analysis.

RESULTS

A relatively high frequency of ε4 in Granada (eastern Andalusia), as well as a low ε2 frequency in Huelva (western Andalusia) were observed. The finding that ε4 allele in Southern Spain and Portugal is higher than expected given its geographical location poses an interesting question for this study, given the well-established APOE-ε4 gradient in Europe.

CONCLUSION

This population study may represent useful information for further prospective anthropological and molecular genetic studies focused on unravelling the relationship between population genetic composition and specific human diseases.

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.

Ideal lipid profile and genes for an extended life span

PURPOSE OF REVIEW

The world population is aging and a rapid increase is being seen in the very elderly (aged >80 years). Cholesterol levels in general rise with age and high cholesterol has been associated with extreme longevity. The relationship between lipids and cardiovascular events in the extreme elderly is unclear.

RECENT FINDINGS

A number of genetic factors associated with lipid metabolism have also been described as having potential antiaging roles, including the genes encoding lipoprotein-associated factors - apolipoprotein E and cholesterol ester transfer protein; adipose tissue metabolism - adiponectin, leptin, glycaemia; and blood pressure - angiotensinogen. Clinical trials of lipid-lowering therapies have recruited subgroups of moderately elderly patients, but only the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) trial specifically recruited an elderly population. There is no direct equivalent of the Hypertension in the Very Elderly trial (HYVET) study of antihypertensive patients in the extreme elderly. No heterogeneity has been seen with the effects of statin therapy in the elderly compared with younger age groups on classical cardiovascular endpoints of coronary heart disease and stroke.

SUMMARY

The optimal cholesterol target, long-term tolerability and the specific effects of statins on other vascular-associated diseases of aging, for example arterial aneurysms, microvascular renal and cerebral disease (dementias), remain to be determined.

APOE and FABP2 Polymorphisms and History of Myocardial Infarction, Stroke, Diabetes, and Gallbladder Disease

Dysfunctional lipid metabolism plays a central role in pathogenesis of major chronic diseases, and genetic factors are important determinants of individual lipid profiles. We analyzed the associations of two well-established functional polymorphisms (FABP2 A54T and APOE isoforms) with past and family histories of 1492 population samples. FABP2-T54 allele was associated with an increased risk of past history of myocardial infarction (odds ratio (OR) = 1.51). Likewise, the subjects with APOE4, compared with E2 and E3, had a significantly increased risk of past history myocardial infarction (OR = 1.89). The OR associated with APOE4 was specifically increased in women for past history of myocardial infarction but decreased for gallstone disease. Interactions between gender and APOE isoforms were also significant or marginally significant for these two conditions. FABP2-T54 allele may be a potential genetic marker for myocardial infarction, and APOE4 may exert sex-dependent effects on myocardial infarction and gallbladder disease.

Apolipoprotein E genotypes modulate fibrosis progression in patients with chronic hepatitis C and persistently normal transaminases

BACKGROUND AND AIM

Carriage of the apolipoprotein E (Apo E) variants, E2, E3 and E4, affects cholesterol metabolism and may be involved in the persistence of hepatitis C virus (HCV) infection. Our aim was to verify whether carriage of specific Apo E variants modulates the course of hepatitis C.

METHODS

We studied a cohort of 116 HCV-positive patients (49 male subjects) with persistently normal transaminases and an Ishak staging score ≤ 2 at an initial biopsy. These untreated patients underwent regular clinical monitoring (median histological follow up: 10 years). Apo E variants were genotyped and results were related to the histological outcome.

RESULTS

The mean ± standard deviation staging scores were 0.9 ± 0.7 at entry versus 1.9 ± 1.2 at the end of follow up, P < 0.0001. Initial and final staging scores in the E3/E3 homozygotes (n = 74) were 1.0 ± 0.7 versus 2.1 ± 1.3, P < 0.0001, while in the remaining patients (n = 42) they were 0.9 ± 0.6 versus 1.5 ± 1.0, P < 0.002. A synergistic effect was observed between Apo E polymorphisms and baseline serum cholesterol values: patients not carrying any E3 allele, as well as carriers of a single E3 allele with serum cholesterol concentration > 190 mg/dL were more likely to have a favorable outcome (final vs initial staging score increased in 7/66, did not change in 10/46, and decreased in 3/4, P <0.005).

CONCLUSIONS

Some of the variability in the natural history of patients with persistently normal transaminases with initially mild hepatitis C can be related to their Apo E genetic background.

Multiple mucin genes polymorphisms are associated with gallstone disease in Chinese men

BACKGROUND

Gallstone is a complex disease caused by multiple environmental and genetic factors. One of these is mucin glycoproteins. This case-control study aimed to investigate the association between single nucleotide polymorphisms (SNPs) at the MUC1-4 genes and gallstone.

METHODS

The study included 475 cases and 941 controls. Eight tagging SNPs were selected: one at MUC1, two at MUC2, and five at MUC4. There was no available tagging SNP at MUC3. Genetic effects were initially evaluated by multivariate logistic regression. The combined effects from multiple genes were further evaluated, as well as the sex-specific effect. Permutation was used to correct for multiple testing.

RESULTS

The genotypes were all in Hardy-Weinberg equilibrium. SNP rs7396030 at MUC2 yielded a p value of 0.03. Further sex-specific analysis showed significance solely with male subjects (p=0.005). Similarly, SNP rs4072037 at MUC1 was only significant (p=0.035) in males. The permutation empirical p values were 0.005 for rs7396030 and 0.02 for rs4072037. For males, the combined genetic effect yielded an OR of 4.68 (p=0.0008).

CONCLUSIONS

The SNPs at MUC1 and MUC2 are significantly associated with gallstone in men but not in women. These genes can work jointly to further increase susceptibility to gallstone in a Chinese population.

[The association between Apolipoprotein E genotype and lipid profiles in healthy woman workers]

OBJECTIVES

Plasma lipid profiles and Apolipoprotein E (ApoE) are established risk factors for cardiovascular disease (CVD). The knowledge of lipid profile may estimate the potential victims of cardiovascular disease before its initiation and progression and offers the opportunity for primary prevention. The most common ApoE polymorphism has been found to influence plasma lipid concentrations and its correlation with CVD has been extensively investigated in the last decade.

METHODS

The ApoE polymorphism and its influence on plasma lipid were investigated in healthy woman workers. The information on confounding factors was obtained through a self-administered questionnaire and ApoE polymorphism was investigated using PCR.

RESULTS

The relative frequencies of alleles E2, E3 and E4 for the study population (n=305) were 0.127, 0.750 and 0.121, respectively. ApoE polymorphism was associated with variations in plasma HDL-cholesterol lipid profile. In order to estimate the independent effects of alleles E2 and E4, as compared with E3, on lipid profile, multiple regression was performed after adjustment for confounding variables such as age, BMI, blood pressure, education status, insulin, fasting glucose, HOMA-IR, menopause. ApoE2 had a negative association with HDL cholesterol and ApoE4 had a positive association with LDL cholesterol.

CONCLUSIONS

This study identified that the ApoE and CVD risk factors contribute to the lipid profiles, similar to other studies. The analysis including dietary intake and other gene in further studies may help to identify clear effects on lipid profiles as risk factor for CVD.

Genetic polymorphism at the apolipoprotein E locus affects the outcome of chronic hepatitis B

Apolipoprotein E (ApoE) and H (ApoH) genotypes are known to affect plasma lipoprotein concentrations. By modulating transport and entry of the hepatitis B virus into hepatocytes, apolipoproteins may influence the course of infection. To verify this hypothesis, 105 patients with chronic HBV infection were examined. Sixty-two of the patients were followed-up for a median time of 21 years. One hundred two controls were included. ApoE and ApoH genotypes were determined by the restriction fragment length polymorphism method. A trend was found for progressive overrepresentation of ApoE3/E3 among patients with advanced liver disease: 13/27 (48%) of inactive HBV carriers, 36/61 (59%) of chronic hepatitis B patients and 16/17 (94%) of patients who received liver transplants (P < 0.005). Being an E3/* carrier was associated with a lower probability of loss of HBsAg: 9/56 (16%) versus 3/6 (50%) (P < 0.05); it was also associated with a longer time before HBsAg loss (P < 0.05). No influence of ApoH genotypes on clinical outcomes was found. The probability of disease progression was higher, and that of loss of HBsAg was lower, among patients with the ApoE3 allelic variant. Downregulation and/or reduced binding of the LDL receptor may explain the more benign course of hepatitis B among carriers of ApoE2-E4.

Apolipoprotein epsilon4 allele is associated with psoriasis severity

Many reports provided strong evidence of the influence of genetic factors in the pathogenesis of psoriasis (Ps). A higher prevalence of lipid disorders in psoriatic patients has been reported. Because apolipoprotein E (apoE) is involved in lipid metabolism, APOE gene variants could be candidates to influence Ps-risk. However, data about the potential influence of the APOE genotypes in Ps are inconclusive. Our objective was to investigate the relationship between the common APOE-epsilon2/epsilon3/epsilon4 variation and Ps in a Caucasian population. Our study involved 331 unrelated Ps-patients and 400 healthy controls. Patients and controls were genotyped for the APOE-epsilon2/epsilon3/epsilon4 polymorphism, and allele and genotype frequencies were statistically compared between the two groups and between patients according to disease severity. Mean lipid values were also compared between the APOE genotypes. Allele and genotype frequencies did not differ between patients and controls. APOE-epsilon4 carriers were significantly more frequent in patients with severe Ps compared to controls (P = 0.003) and to non-severe Ps (P = 0.017). No significant difference in mean lipid values was found between the APOE genotypes. The APOE-epsilon4 allele could be a risk factor for developing a severe form of psoriasis.

APOE distribution in world populations with new data from India and the UK

BACKGROUND

The APOE gene and its protein product is associated with a number of plasma proteins like very-low density lipoprotein (VLDL), high density lipoprotein (HDL) chylomicrons, chylomicron remnants, and plays a crucial role in lipid metabolism. The APOE gene is polymorphic and common alleles (*E2, *E3 and *E4) have been associated with a number of common and complex diseases in different populations. Due to their crucial role in metabolism and clinical significance, it is imperative that allelic variation in different populations is analysed to evaluate the usage of APOE in an evolutionary and clinical context.

AIM

We report allelic variation at the APOE locus in three European and four Indian populations and evaluate global patterns of genetic variation at this locus. The large, intricate and unexpected heterogeneity of this locus in its global perspective may have insightful consequences, which we have explored in this paper.

SUBJECT AND METHODS

Apolipoprotein E genotypes were determined in four population groups (Punjabi Sikhs, Punjabi Hindus, Maria Gonds and Koch, total individuals = 497) of India and three regionally sub-divided British populations (Nottinghamshire, East Midlands and West Midlands, total individuals = 621). The extent and distribution of APOE allele frequencies were compared with 292 populations of the world using a variety of multivariate methods.

RESULTS

Three alleles, APOE*E2, APOE*E3 and APOE*E4, were observed with contrasting variation, although *E4 was absent in the tribal population of Koch. Higher heterozygosities (>43%) in British populations reflected their greater genetic diversity at this locus. The overall pattern of allelic diversity among these populations is comparable to many European and Indian populations. At a global level, higher frequencies of the *E2 allele were observed in Africa and Oceania (0.099 +/- 0.083 and 0.111 +/- 0.052, respectively). Similarly, *E4 allele averages were higher in Oceania (0.221 +/- 0.149) and Africa (0.209 +/- 0.090), while Indian and Asian populations showed the highest frequencies of *E3 allele. The coefficient of gene differentiation was found to be highest in South America (9.6%), although the highest genetic diversity was observed in Oceania (48.7%) and Africa (46.3%). APOE*E2 revealed a statistically significant decreasing cline towards the north in Asia (r = -0.407, d.f. = 70, p < 0.05), which is not compatible with the coronary heart disease statistics in this continent. APOE*E4 showed a significant increasing cline in North European populations. Spatial autocorrelation analysis shows that the variation at this locus is influenced by 'isolation by distance' with a strong positive correlation for lower distances up to 1313 km.

CONCLUSION

Overall APOE allelic variation in UK and Indian populations is comparable to previous studies but in tribal populations *E4 allele frequency was very low or absent. At a global level allelic variation shows that geography, isolation by distance, genetic drift and possibly pre-historical selection are responsible for shaping the spectrum of genetic variation at the APOE gene. Overall, APOE is a good anthropogenetic and clinical diagnostic marker.

Association between apolipoprotein E polymorphism, lipids, and coronary artery disease in Tunisian type 2 diabetes

BACKGROUND

The relationship between apolipoprotein E (ApoE) polymorphism, fasting lipid parameters, and coronary artery disease (CAD) is controversial.

METHODS

We studied this relationship, for the first time, in Tunisian type 2 diabetic patients. The studied population comprised 157 type 2 diabetic patients (145 of them were not on any lipid-lowering drugs). Fasting lipids were measured by enzymatic methods and ApoE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Our results showed that the alleles E2, E3, and E4 were found in 4%, 88%, and 8% of patients, respectively. In the total type 2 diabetic population, no association was found between ApoE polymorphism, lipid parameters, and CAD. However, the E4 allele was associated with elevated low-density lipoprotein cholesterol concentration and with CAD in type 2 diabetic men.

CONCLUSION

The effect of ApoE polymorphism on CAD is gender-dependent in the Tunisian type 2 diabetic population. ApoE 4 allele may enhance atherogenesis indirectly by a strong effect on low-density lipoprotein cholesterol.

Polymorphisms of genes in the lipid metabolism pathway and risk of biliary tract cancers and stones: a population-based case-control study in Shanghai, China

Biliary tract cancers, encompassing the gallbladder, extrahepatic bile duct, and ampulla of Vater, are uncommon yet highly fatal malignancies. Gallstones, the primary risk factor for biliary cancers, are linked with hyperlipidemia. We examined the associations of 12 single nucleotide polymorphisms of five genes in the lipid metabolism pathway with the risks of biliary cancers and stones in a population-based case-control study in Shanghai, China. We included 235 gallbladder, 125 extrahepatic bile duct, and 46 ampulla of Vater cancer cases, 880 biliary stone cases, and 779 population controls. Subjects completed an in-person interview and gave blood. Genotyping was conducted by TaqMan assay using DNA from buffy coats. The effects of APOE IVS1+69 (rs440446) and APOB IVS6+360C>T (rs520354) markers were limited to men. Men carrying the G allele of APOE IVS1+69 had a 1.7-fold risk of stones [95% confidence interval (95% CI), 1.2-2.4], a 1.8-fold risk of gallbladder cancer (95% CI, 1.0-3.3), a 3.7-fold risk of bile duct cancer (95% CI, 2.0-7.0), and a 4-fold risk of ampullary cancer (95% CI, 1.4-12.4). Male carriers of the T allele of APOB IVS6+360C>T had a 2-fold risk of bile duct cancer (95% CI, 1.2-3.4). The APOB T-T haplotype (APOB IVS6+360C>T, EX4+56C>T) was associated with a 1.6-fold risk of bile duct cancer (95% CI, 1.1-2.3). Male and female carriers of the T allele of LDLR IVS9-30C>T (rs1003723) had a 1.5-fold risk of bile duct cancer. Our findings suggest that gene variants in the lipid metabolism pathway contribute to the risk of biliary tract stones and cancers, particularly of the bile duct.

Apolipoprotein E Genotypic Frequencies Among Down Syndrome Patients Imply Early Unsuccessful Aging for ApoE4 Carriers

Down syndrome (DS) might be considered a model for unsuccessful and early aging, possibly accelerated for those who carry the APOE4 allele associated with common age-related diseases, e.g., Alzheimer's disease and a poor prognosis after acute myocardial infarction, causing lower ApoE4 frequencies among the very old in general populations. We compared ApoE genotypic frequencies found for healthy adults (n = 211, age < 40; n = 79, ages 70-79; n = 71, ages > 90) to those found for DS patients (n = 106, mean age 9 years), all living in western Sicily. We found that the frequency of the ApoE23 genotype increased with age among the healthy adults (8.5%, 6.4%, 19.7%; p = 0.024) while ApoE34 frequency decreased (16.1%, 12.6%, 4.1%; p = 0.012). DS patients had APOE34 genotypic frequencies very similar to those found in septuagenarians (9%; p = 0.005). Analyzing results according to surviving rate of persons with DS, an age-related reduction of ApoE3/4 genotype frequency was found comparing =5 years old to >5 years old DS subjects. These results highlight DS as a model to understand the role of APOE4 allele in unsuccessful ageing considering that a number of proinflammatory supernumerary genes (Cu/Zn superoxide dismutase, Ets-2 transcription factors, Down syndrome critical region 1, stress-inducible factor, interferon-alpha receptor and the amyloid precursor protein) are located on chromosome 21 and are implied in the pathologic processes of DS.

Apolipoprotein E polymorphism in Southern Iran: E4 allele in the lowest reported amounts

BACKGROUND

Apolipoprotein E (apoE) with three major alleles E2, E3 and E4 is one of the critical genes in lipid metabolism. Common apoE alleles are in association with an increase in risk for central nervous and cardiovascular diseases such as Alzheimer's disease, dementia, multiple sclerosis, atherosclerosis, coronary heart disease, hyperlipoproteinemia and stroke. ApoE3 is known as the most frequent allele in all populations, while association of apoE gene polymorphism with reported diseases have mostly been related to other two major alleles especially apoE4.

OBJECTIVE

To determine of apoE alleles frequencies in Southern Iran and comparison of those frequencies with other populations.

METHODS

DNA was extracted from the whole blood of 198 healthy unrelated candidates from population of Fars Province, Southern Iran, for apoE genotyping who were checked up by a physician. The frequencies of apoE alleles were compared with other populations by chi(2) test.

RESULTS

The frequencies of E2, E3 and E4 were 0.063, 0.886 and 0.051 respectively. These values were similar to those reported from populations of Kuwait, Oman, Lebanon, India, Turkey, Greece, Spain, Sardinia Islands of Italy and two Iranian populations but were different from South of Italy and Caucasians in other Europe regions, American, American-Indian, African, East Asian and Saudi populations (P < 0.05).

CONCLUSION

The frequency of E4 allele as a genetic risk factor for some multifactorial diseases in the population of Southern Iran is in the lowest reported amounts in the world. Iranian population has Caucasoid origin but differs from some Caucasian populations in Europe and America. The results of present study are in agreement with the historical evidences which show admixture of Iranian population with other populations and some studies based on genetic polymorphisms in the population of Southern Iran.

Apolipoprotein E polymorphism influences lipid phenotypes in Chinese families with familial combined hyperlipidemia

BACKGROUND

Apolipoprotein E (apoE) polymorphism is associated with changes in the lipoprotein profile of individuals with familial combined hyperlipidemia (FCHL), but its effects on the lipoprotein profiles of members of Chinese families with FCHL remain uncertain.

METHODS AND RESULTS

43 FCHL families (n=449) and 9 normolipidemic families (n=73) were recruited to assess the influence of apoE polymorphism on plasma lipids. The relative frequency of the epsilon4 allele in affected and unaffected FCHL relatives, spouses and normolipidemic members was 13.8%, 5.3%, 9.1% and 6.8%, respectively, with a significantly higher frequency in affected FCHL relatives, compared with unaffected FCHL relatives or normolipidemic members (p=0.0002 or p=0.029). In FCHL relatives, the apoE4 subset (E4/4 and E4/3) exhibited significantly higher levels of apoB, total cholesterol and low-density lipoprotein-cholesterol (LDL-C) than did the apoE3 (E3/3) subset, especially in women (all p<0.05), and there was significant elevation of LDL-C concentrations in men only (p<0.05). In men, the apoE2 (E3/2) subset indicated a decreased level of apoB and increased apoA1 compared with those in the apoE3 subset (p<0.05).

CONCLUSIONS

ApoE polymorphism appears to be associated with variance of the lipoprotein phenotype in Chinese families with FCHL.

Preventive neurosurgery: population-wide check-up examinations and correction of asymptomatic pathologies of the nervous system

BACKGROUND

Prevention in healthcare is attracting more and more attention. Early identification and correction of anomalies harbouring the risk of a catastrophic event such as aneurysms is the principal rationale for brain check-up programmes. The other aim of preventive screening is to identify progressive lesions with little reversibility such as gliomas. The purpose of the current analysis is to review the frequency of the various incidental findings, the inherent risk and the therapeutic options. RATIONALE FOR CHECK-UP IMAGING AND PREVENTIVE TREATMENT: The average prevalence of asymptomatic intracranial benign tumours, aneurysms and carotid stenoses must be estimated as approximately 1% each. Meningiomas, aneurysms and carotid stenosis become more frequent with increasing age. Mainly vascular anomalies harbour a risk of a catastrophic event, i.e. carotid stenosis and intracranial aneurysms. Only gliomas potentially lose reversibility with time passing. The case of glioma appears to be lost since asymptomatic gliomas are extremely rarely identified on screening examinations, and on the other hand current treatment series do not support that infiltrating gliomas can be cured if only treated early enough. Treatment of the benign tumours, hydrocephalus and arachnoid cysts in the asymptomatic stage does not appear to provide any benefit. RATIONALE FOR GENETIC SCREENING: A number of intracranial tumours, vascular anomalies and degenerative changes are genetically determined. Examples are neurofibromatosis, tuberous sclerosis, von Hippel-Lindau disease and Rendu-Osler's disease. Although familial clustering of aneurysms is well known, the exact genetic anomaly is unknown and probably several genes play a role. Because of the variable penetrance of the inherited disorders with known genetic alterations, screening of affected families is recommended. The conditions are too rare to justify screening of the entire population. Apolipoprotein E genotype is the only accepted predictor of dementia. Routine screening APOE may be considered today, but is highly problematic due to the lack of clear consequences and the potentially negative psychological impact.

COSTS

Implementation of population-wide screening programmes and preventive measures would lead to a substantial additional financial burden. Brain-check-up programmes cannot be considered in isolation. Cardiovascular and oncological programmes would also have to be included from that point of view.

CONCLUSIONS

Population-wide screening with regard to intracranial aneurysms or carotid stenosis with non-invasive imaging techniques and preventive surgery/endovascular therapy can be justified, provided that treatment-associated morbidity is very low. There is no evidence for the rationale of screening for asymptomatic intracranial tumours, cysts or hydrocephalus. Genetic screening cannot be generally recommended, except among families affected by inherited conditions.

Influencia de los factores genéticos y ambientales en el metabolismo lipídico y riesgo cardiovascular asociado al gen apoE

The apolipoprotein E (ApoE) plays an important role in lipid metabolism. This apoprotein presents three major isoforms (apoE2, apoE3 and apoE4) that modulate lipid levels. Carriers of the apoE4 allele have higher total and LDL-cholesterol plasma concentration and a greater coronary risk, particularly for myocardial infarction. Nevertheless, not all the people with this allele develop the disease, which suggests that other genetic or environmental factors are necessary for its total expression. In this review, we will analyze the importance of several polymorphisms in the apoE gene promoter region, as well as various environmental factors, including diet, in the association of this gene with lipid metabolism and cardiovascular risk.

No association of apolipoprotein E epsilon4 genotype with faster progression or less recovery of relapses in a Spanish cohort of multiple sclerosis

BACKGROUND

Recent data have suggested a faster deterioration of multiple sclerosis (MS) patients who harbour the epsilon4 allele of the apolipoprotein E (APOE) gene. We investigate the relationship of APOE genotypes with disease severity and clinical recovery of relapses in a MS population of the north of Spain.

METHODS

One hundred and thirty-three patients with clinically defined MS were studied. Disease course (relapsing versus progressive), age of onset, duration of the disease and disability measured by the Expanded Disability Status Scale (EDSS) were recorded. Worsening was measured by the Progression Index (PI) and by EDSS 4 and 6 latencies. In 79 patients with relapsing-remitting (RR) MS the degree of clinical recovery of relapses (total versus partial) was assessed.

RESULTS

The frequency of the APOE epsilon4 allele in our patients was similar to that found in other southern European populations. APOE epsilon4 patients did not have a faster progression as assessed by PI and EDSS 4 and 6 latencies. Among 79 patients with RRMS there were no significant differences in the degree of recovery of relapses.

CONCLUSIONS

In this MS population, APOE epsilon4 polymorphism is not associated with a more severe clinical course and does not appear to influence recovery of exacerbations.

The effect of the APOE polymorphism on HDL-C concentrations depends on the cholesterol ester transfer protein gene variation in a Southern European population

BACKGROUND

Apolipoprotein E (ApoE) locus has consistently shown a significant association with low-density lipoprotein cholesterol (LDL-C). However, its impact on high-density lipoprotein cholesterol (HDL-C) has been highly controversial suggesting that it may be context-dependent. We examined the gene-gene interaction between the common ApoE and the CETP polymorphisms in determining HDL-C concentrations in men and women from the general population.

METHODS

550 unrelated Caucasian subjects were randomly selected from a Mediterranean Region in Spain. Plasma lipids, anthropometric, clinical and lifestyle variables were measured. Common ApoE and CETP-TaqIB polymorphisms were determined.

RESULTS

We have found a gene-gene interaction between and ApoE and the CETP loci in determining HDL-C concentrations. Thus, after adjustment for gender, age, body mass index, tobacco smoking, alcohol consumption, physical exercise and medication, carriers of the E4 allele had lower HDL-C concentrations [mean and (standard error): 40.1 (2.6) mg/dL] than E2 subjects [47.7 (3.2) mg/dL; p=0.019], and even lower than those of the E3 subjects [44.7 (1.4) mg/dL; p=0.042], only if they had the B1B1 genotype. However, mean HDL-C concentrations were higher among those with E4 allele carrying the B2 allele at the CETP gene locus [50.5 (2.3) mg/dL], and lower among E2 subjects carrying the B2 allele [45.5 (2.6) mg/dL]. This interaction was observed in both men and women. This gene-gene interaction remained statistically significant even after additional adjustment for triglycerides.

CONCLUSIONS

The effect of the ApoE polymorphism on HDL-C concentrations depends on the CETP polymorphism, explaining some of the controversial results previously reported for this polymorphism.

A Module Map Showing Interaction between Apolipoprotein E and Phospholipase A2 Polymorphism in Lipid Profiles

OBJECTIVE

Establish a possible conceptual relationship among Apo E and PLA2 polymorphism and lipid profiles.

METHODS

Five hundred subjects aged 65 to 74 years were randomly selected from a community in southern Taiwan to assess the relationship between Apo E and PLA2 polymorphisms and lipid profiles. Two hundred fifty-six participants agreed to have venous blood drawn for DNA studies.

RESULTS

By multiple linear regression, the PLA2 A2 allele showed a statistically significant influence on LDL-C (p = 0.0097), and the Apo epsilon2 allele showed a statistically significant influence on HDL-C (p = 0.0004), however, the interaction between the PLA2 A2 allele and the Apo epsilon2 allele was found to be significant in the blood fraction of HDL-C (p = 0.0388) and LDL-C (p = 0.0002). Decreasing HDL-C and increasing LDL-C were found when the PLA2 A2 and Apo epsilon2 allele co-existed.

CONCLUSION

The presence of a physiologic balance contributes significantly to homeostatic and compensatory responses regulating blood HDL-C and LDL-C profiles. A module map of the generation-control cycle and conditional activity among Apo E, PLA2, and lipid levels is presented, and both behaviours and biological perspectives under the consilience model may suggest a new approach to many kinds of complex disorders.

apoE4 allele and the natural history of cardiovascular risk factors

The aims of the present study were to compare the longitudinal changes in traditional cardiovascular (CV) risk factors (blood pressure, BMI, total and HDL-cholesterol, triglycerides, and blood glucose) in men with and without the apolipoprotein (apo)E4 allele. Three hundred six men from the Baltimore Longitudinal Study of Aging, ranging in age from 20 to 92 yr, were studied. Repeated measurements of CV risk factors were performed over a median follow-up time of 7 yr (maximum 14.3 yr) for men. Longitudinal changes in these CV risk factors were analyzed by linear mixed-effects models. The prevalence of the apoE4 allele was 25.5%. apoE4 was independently associated with accelerated changes over time in fasting plasma glucose (+9.5% vs. no change in those without apoE4 in the 6th age-decade over 10 yr). No significant effect of apoE4 on longitudinal changes in total or HDL-cholesterol, triglycerides, or blood pressures was observed. In conclusion, apoE4 influences fasting plasma glucose and its changes over time. This could explain, in part, the increased CV risk associated with the apoE4 genotype observed in men.

The effect of apolipoprotein E polymorphism on lipid levels in Korean adults

The aim of this study was to determine the effects of polymorphisms in the apolipoprotein E gene (APOE) on lipid levels in Korean adults and to investigate the interactions between these polymorphisms and environmental factors in determining lipid levels. We performed a cross-sectional study of 1,900 subjects (668 men and 1,232 women; 45-74 yr old) in Namwon, Korea, in 2004. APOE polymorphisms were determined by polymerase chain reaction and restriction enzyme analysis. Carriers of the APOE*E2 (E2) allele had significantly lower total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations than did carriers of the APOE*E3 (E3) or APOE*E4 (E4) alleles, regardless of gender. The APOE allele type had significant effect on high-density lipoprotein cholesterol (HDL-C) and triglyceride levels in women, but not in men. The effect of APOE allele type on HDL-C levels was modified by age in women. In addition, in men, the effect of APOE allele type on triglyceride levels was modified by smoking. These findings highlight the important effect of gene-environment interactions on lipid levels.

Influence of apolipoprotein E genotype on fat-soluble plasma antioxidants in Spanish children

BACKGROUND

Apolipoprotein (apo) E is a major determinant of plasma lipid concentrations, which in turn influence the plasma concentrations of various fat-soluble vitamins.

OBJECTIVE

We aimed to analyze the effect of APOE genotype on fat-soluble antioxidant concentrations in children.

DESIGN

A total of 926 healthy boys and girls aged 6-8 y were selected from 4 cities in Spain. APOE genotyping was carried out, and plasma concentrations of lipids, apolipoproteins, and lipid-soluble antioxidants were measured.

RESULTS

Plasma lipid concentrations were strongly influenced by APOE genotype. The mean plasma concentration of alpha-tocopherol was 21.3 micromol/L, which is one of the highest values ever reported for a population of children. Although plasma concentrations of alpha-tocopherol, gamma-tocopherol, lycopene, and alpha-carotene varied significantly between subjects with different APOE genotypes, most of these differences disappeared after adjustment for lipoprotein-related covariates. Nevertheless, tocopherol concentrations remained elevated in individuals with the E2/2 genotype. Multivariate regression analysis showed interactions of APOE genotype with triacylglycerol and apo B in determining alpha-tocopherol concentrations. When subjects were stratified according to major apo E groups, apo B appeared to be the most important predictor of alpha-tocopherol concentrations in all groups, whereas triacylglycerol was identified only in carriers of the E2 allele.

CONCLUSIONS

The association between APOE genotype and lipophilic antioxidant concentrations is dependent mainly on the effect of the polymorphism on lipoprotein concentrations. However, triacylglycerol plays a role in determining the variability of alpha-tocopherol concentrations in E2 carriers only. This suggests that the alpha-tocopherol content in each lipoprotein class varies according to APOE genotype.

Apolipoprotein E polymorphism modifies the alcohol-HDL association observed in the National Heart, Lung, and Blood Institute Family Heart Study

BACKGROUND

The apolipoprotein E gene (APOE) allele epsilon4 is associated with an increased risk of cardiovascular disease. The presence of the epsilon4 allele has been associated with lower concentrations of HDL cholesterol, but it is not known whether the epsilon4 allele modifies the association between alcohol consumption and HDL-cholesterol concentrations.

OBJECTIVE

The objective of the study was to assess whether the epsilon4 allele modifies the association between alcohol consumption and HDL-cholesterol concentrations.

DESIGN

In a cross-sectional design, we studied 670 men and women aged 26-78 y who participated in the National Heart, Lung, and Blood Institute Family Heart Study to assess whether the epsilon4 allele of the gene APOE modifies the association between alcohol consumption and HDL-cholesterol concentrations. Alcohol data were self-reported, and we used multivariate, generalized estimating equations to assess interactions.

RESULTS

In a model with adjustment for age, sex, body mass index, smoking, exercise, waist-hip ratio, TV viewing, and study site, there was a significant effect of the interaction between the epsilon4 allele and alcohol consumption on HDL cholesterol (P=0.0001). In the absence of the epsilon4 allele, multivariate adjusted means of HDL were 1.24, 1.36, and 1.54 mmol/L among subjects who never drank and those who currently drink 0.1-12 and >12 g alcohol/d, respectively; in the presence of the epsilon4 allele, the corresponding values were 1.19, 1.27, and 1.25 mmol/L.

CONCLUSION

Our data show a significant effect of the interaction between the epsilon4 allele and alcohol consumption on HDL. The increase in HDL associated with alcohol appears to be stronger in subjects without the epsilon4 allele than in those with the epsilon4 allele.

Obesity and alcohol modulate the effect of apolipoprotein E polymorphism on lipids and insulin

OBJECTIVE

To assess the interaction between apolipoprotein (apo) E polymorphism, alcohol consumption, and BMI on insulin, lipid, and lipoprotein levels in men.

RESEARCH METHODS AND PROCEDURES

Cross-sectional study of 266 healthy men without hypolipidemic or antidiabetic drug treatment. BMI, apo E polymorphisms, insulin, and lipid and lipoprotein levels were assessed. Alcohol consumption was assessed by questionnaire. epsilon2/epsilon4 carriers were excluded from the analysis.

RESULTS

On bivariate analysis, epsilon2 carriers had lower levels of total and low-density lipoprotein cholesterol and higher levels of apo E and lipoparticle B:E than epsilon3 carriers, the opposite being found for epsilon4 carriers compared with epsilon3 carriers; epsilon4 carriers also had significantly higher insulin levels. On multivariate analysis, significant interactions (p < 0.04) between apo E alleles and increased BMI were found for total and low-density lipoprotein cholesterol and insulin levels, the increase in those parameters with BMI being stronger among epsilon4 carriers than among epsilon3 or epsilon2 carriers. Significant interactions (p < 0.02) between apo E alleles and alcohol consumption were also found for apo B levels, which increased in epsilon2 carriers but remained relatively stable in epsilon3 and tended to decrease in epsilon4 carriers.

DISCUSSION

These data suggest that effects of apo E alleles on lipids and insulin levels are partly dependent on environmental variables such as BMI and alcohol intake. These findings highlight the importance of gene x environment interactions on the deleterious effect of obesity on cardiovascular risk factors.

Apolipoprotein E polymorphism and carotid atherosclerosis in patients with coronary disease

BACKGROUND

Apolipoprotein (apo) E polymorphism plays a role in the development of coronary disease, but their involvement in carotid atherosclerosis is controversial. The aim of this study was to evaluate the role of apo E polymorphism in the development of subclinical carotid atherosclerosis in patients with coronary disease.

METHODS

In 226 consecutive patients with coronary disease, apo E genotypes were performed by PCR and restriction analysis. Intima-media thickness (IMT) and the presence of atherosclerotic plaques in carotid arteries were evaluated by two-dimension ultrasonography.

RESULTS

Apo E allele frequencies were: 3=0.70, 4=0.22 and 2=0.08. The only patient with 2/4 genotype was excluded for the analysis. The patients were divided in three groups according to apo E genotype: E2 (2/2, 2/3), E3 (3/3) and E4 (4/4, 4/3). Patients of E4 group had higher values of low-density-lipoprotein (LDL) cholesterol and apo B than patients of E2 group (P< or =0.01). Carotid IMT mean was not different in E3 (0.81+/-0.21 mm), E4 (0.83+/-0.23 mm) and E2 groups (0.76+/-0.17 mm) (P=0.52). Mean differences of IMT in E3 group were not different from those of E2 or E4 groups after adjusting for age and gender in a first analysis, and for age, gender and LDL cholesterol levels in a second one. The number of plaques in apo E3 group was similar to that in apo E2 or apo E4 groups, after adjusting for the same variables.

CONCLUSIONS

A relationship between subclinical carotid atherosclerosis and apo E polymorphism is not found in patients with coronary disease.

Apolipoprotein E gene polymorphism effects triglycerides but not CAD risk in Caucasian women younger than 65 years

The pathogenesis of CAD is similar in man and woman, yet some risk factors have a greater impact on the CAD risk in woman than in man. In this study we assessed the effect of the apoE gene polymorphism on lipid metabolism and risk for CAD in women younger than 65 years (premature CAD). In a cross-sectional case-control study, 147 female Caucasian patients with premature CAD (confirmed by coronarography) were compared with a control group of 114 healthy Caucasian women. The apoE allele frequencies of patients vs. controls were 5.1% vs. 5.7% for 2, 85.4% vs. 83.3% for 3, and 9.5% vs. 11% for epsilon4. The subjects with epsilon2/3 genotype had statistically significantly higher triglycerides levels than the subjects with epsilon3/3 genotype (2.23 +/- 2.13 mmol.L(-1) vs. 1.73 +/- 0.84 mmol.L(-1); p<0.05). Logistic regression analysis revealed no association between risk genotypes (3/4 and 4/4) of the apoE gene polymorphism and CAD risk (OR 0.9; 95% CI 0. 5-1.7, P=0.7). We observed metabolic clustering of diabetes mellitus, arterial hypertension, higher BMI and triglycerides, and lower HDL cholesterol in the CAD group compared to the control group. Arterial hypertension, diabetes, HDL cholesterol level, and BMI were independent risk factors for premature CAD in female population, whereas, the risk genotype of the apoE gene polymorphism was not. In conclusion, in Slovene women risk genotypes of the apoE gene polymorphism are not associated with premature CAD; a metabolic clustering of diabetes, HDL, triglycerides and arterial hypertension is frequently present in Caucasian women with premature CAD.

Apolipoprotein E polymorphism and atherosclerosis

The relationship between apolipoprotein (apo) E and vascular disease has been the subject of a considerable amount of research. However, this relationship is far from clearly defined. This deficiency appears to be due to a multitude of factors. Among these are differences in ethnicity, age (and possibly gender), diagnostic criteria, and environmental factors (eg, diet and smoking) that have contributed to the contradictory findings. Several diseases and their treatment may also influence this relationship. There are also documented interactions between apo E genotypes and other genes or vascular risk factors. One possible clinically relevant application of identifying the apo E genotype could be to assess the response to a particular drug treatment. It may also be that apo E polymorphism will become a good predictor of vascular death (eg, from myocardial infarction or stroke) rather than an indicator of the risk of developing vascular disease but without an acute ischemic event. More research is required to define the place of apo E genotyping in the management of vascular disease in its various forms. Whatever the future brings, the evaluation of apo E genotypes will need to be rapid, cheap, and technically undemanding before this investigation becomes widely available and clinically relevant.

ApoE polymorphism in a small Mediterranean island: relationships with plasma lipids, lipoproteins and LDL particle size

Polymorphisms of apoE gene are able to modulate lipoprotein metabolism at different steps and to influence LDL-cholesterol (LDL-C) levels and also other lipoproteins features. Population studies documented large differences in the frequency of apoE alleles which could be even related to the prevalence of cardiovascular disease. In this study we evaluated the apoE genotypes and allele frequency in 576 subjects living in a small island in the Tyrrhenian Sea and the relative contribution of apoE polymorphism on plasma lipid and lipoprotein profile, including LDL particle size. We found a cumulative frequency of 0.073, 0.866 and 0.061 for epsilon2, epsilon3 and epsilon4 alleles respectively. Moreover epsilon3 subjects had only triglyceride levels significantly lower and LDL-C and lipoprotein (a) (Lp(a)) levels higher than epsilon2 carriers. LDL-particle size was significant smaller in epsilon2 subjects than both epsilon3 and epsilon4 carriers, but the difference disappeared when data were adjusted for triglycerides. In conclusion we have provided further evidence of a low prevalence of epsilon4 allele in a Mediterranean population which may represent a genetic protective factor of these populations. Environmental factors, such as diet, occurring in this area may have attenuated the influence of this gene on plasma lipoproteins.

The importance of plasma apolipoprotein E concentration in addition to its common polymorphism on inter-individual variation in lipid levels: results from Apo Europe

Interindividual variation in the concentration of plasma lipids which are associated with coronary artery disease (CAD) risk is determined by a combination of genetic and environmental factors. This study investigates the effects of apoE genotype and plasma concentration on cholesterol and triglycerides (TG) levels in subjects from five countries: Finland, France, Northern Ireland, Portugal, and Spain. Age and sex significantly influenced serum cholesterol, TG and apoE concentrations. The age effect differs in males and females. The allele frequencies of the apoE gene, one of the most widely studied CAD susceptibility genes, were determined: the epsilon2 allele frequency and the apoE concentration showed a north-south increasing gradient while the epsilon4 allele frequency showed the reverse. ApoE plays an important role in lipid metabolism. Total cholesterol and TG concentrations were significantly dependent on apoE genotype in both sexes. These differences in lipids between genotypes were more pronounced when plasma apoE concentrations were taken into account.

Influence of birth weight on the apo E genetic determinants of plasma lipid levels in children

To evaluate the influence of birth weight on apolipoprotein (apo) E genetic determinants of plasma lipids levels in prepubertal children we studied 933 healthy children (491 males and 442 females) 6 to 8 years old (mean age of 6.7 y), whose weight was recorded at birth. Plasma lipid and apolipoprotein concentrations and apo E genotypes were determined. We observed a greater effect of the apo E polymorphism on total cholesterol (TC), LDL-cholesterol (LDL-C) and especially apo B levels in children with birth weight in the lower tertile compared with those with birth weights in higher tertiles. Taking the epsilon3 allele homozygosity as reference, in boys with birth weights in the low tertile the overall lowering effect of the epsilon2 allele on TC, LDL-C and apo B was greater (10.5% (p < 0.01), 20.2% (p < 0.01) and 18.8% (p < 0.01), respectively) than in those in the highest tertile (5.6% on TC, 10.3% on LDL-C and 12.6% (p < 0.01) on apo B). A similar trend in this effect between tertiles of birth weight was also observed in girls. For both sexes, linear regression analysis demonstrates a positive and significant interaction between birth weight and epsilon2, which may explain the fact that the decrease in TC, LDL-C and apo B associated with the epsilon2 allele is more marked the lower the birth weight. Taking into account the prevalence of apo E polymorphism, and that appears to be the main genetic factor affecting plasma lipids, the interaction of apo E genotype and birth weight could be an important determinant of TC, LDL-C and apo B levels, and, as a consequence, of atherosclerosis.

Effect of apoE genotype on the hypolipidaemic response to pravastatin in an outpatient setting

BACKGROUND

Considerable variability exists in the plasma lipid and lipoprotein response to statin treatment due, in part, to genetic factors. The gene for apolipoprotein E (ApoE) is polymorphic and the different genotypes modulate baseline lipid levels. The objective of the present study was to evaluate the effect of the apoE genotype on the lipoprotein response to pravastatin treatment in an outpatient population followed-up in several different clinics across Spain. Subjects and methods. Subjects (n=401; 56% female; mean age 57 years), who were hypercholesterolaemic despite a diet poor in saturated fat and cholesterol, were treated according to NCEP-ATP II guidelines. Plasma lipids and lipoproteins were measured centrally before and after 16 weeks of treatment with 20 mg day-1 of pravastatin.

RESULTS

ApoE genotype distributions were 3.2% with varepsilon2/3, 73.1% with varepsilon3/3 and 22.4% with varepsilon3/4 or varepsilon4/4. ApoE genotype did not have any effect on baseline lipid levels except on triglycerides such that the carriers of the varepsilon2 allele had concentrations significantly greater than those subjects with varepsilon3/3 genotype and carriers of the varepsilon4 allele after adjustment for age, gender and body mass index (BMI) (P < 0.001). Once adjusted for age, gender, BMI and baseline lipid levels, the apoE polymorphism did not significantly influence the plasma lipid and lipoprotein response to pravastatin.

CONCLUSION

ApoE genotype appears not to influence the hypolipidaemic effect of pravastatin in patients monitored in a general outpatient setting.

Influence of apolipoprotein E, smoking, and alcohol intake on carotid atherosclerosis: National Heart, Lung, and Blood Institute Family Heart Study

BACKGROUND AND PURPOSE

Apolipoprotein E (apoE) isoforms and lifestyle factors play an important role in the development of coronary heart disease. The association of apoE and carotid atherosclerosis remains controversial.

METHODS

We investigated the relation of apoE, cigarette smoking, alcohol drinking, and their interaction with carotid atherosclerosis on 544 individuals free of coronary heart disease in the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Atherosclerotic lesions of the carotid arteries were detected through high-resolution ultrasound.

RESULTS

Subjects in the apoE4 group had lower blood pressure, lower high-density lipoprotein cholesterol, and higher low-density lipoprotein cholesterol. In a multivariate logistic regression model, apoE isoforms and alcohol consumption were not significantly associated with the prevalence odds of carotid atherosclerosis (P=0.94 and 0.98, respectively, for trend). In contrast, compared with those who never smoked, the prevalence odds ratios for carotid atherosclerosis were 1.7 [95% confidence interval (CI),1.1 to 2.7], 2.8 (95% CI, 1.2 to 6.2), and 1.9 (95% CI, 0.7 to 5.5) for former smokers, current smokers of 1 to 20 cigarettes per day, and current smokers of >20 cigarettes day, respectively (P=0.0018 for trend). We did not find evidence of an interaction between apoE and alcohol consumption. Our data suggested a synergistic effect between the apoE allele epsilon(4) and smoking on carotid atherosclerosis: odds ratios were 1.7 (95% CI, 0.8 to 3.6) for smoking alone, 1.0 (95% CI, 0.6 to 1.8) for epsilon4 alone, and 3.7 (95% CI, 1.1 to 3.6) for the joint presence of the apoE allele epsilon4 and smoking.

CONCLUSIONS

Smoking but not alcohol consumption or ApoE is associated with an increased odds of carotid atherosclerosis. Our data suggest a synergistic effect between the apoE allele epsilon4 and smoking on carotid atherosclerosis.

Influence of apolipoprotein E polymorphism on plasma vitamin A and vitamin E levels

BACKGROUND

Plasma concentrations of vitamins A and E are positively correlated with those of concurrent lipids and, on the other hand, lipid levels are influenced by apolipoprotein E polymorphism. Therefore, the effect of this polymorphism on both vitamins was analysed in an adult population.

MATERIALS AND METHODS

Subjects were recruited from a working population. Their anthropometric, lifestyle and dietary intake variables and menopausal status were recorded. Their apolipoprotein E phenotype and their plasma vitamins A and E (by high-performance liquid chromatography) and lipid (enzymatically) concentrations were determined after an overnight fast. The associations of the phenotype with vitamins and lipids were studied in men and women separately and controlling for significant covariates.

RESULTS

The apolipoprotein E phenotype was associated with the concentrations of total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol in women, whereas no associations with lipids were found in men. Vitamin A and vitamin E levels were higher in men than in women, but only the difference in the former persisted after lipid adjustment. Apolipoprotein E2 slightly increased vitamin A levels in women, an effect which was still evident with lipid adjustment. Actually, both the apolipoprotein E phenotype and triglyceride were selected as significant predictors of this vitamin by multiple regression. This phenotype did not affect vitamin E levels in either sex.

CONCLUSIONS

Lipids do not mediate the effect of gender on vitamin A levels. Apolipoprotein E polymorphism is an independent determinant of vitamin A levels in women. Pending confirmation by others, we propose that enhancement of this vitamin may contribute to the beneficial impact of the epsilon2 allele on human ageing and health.

Apolipoprotein E genotype and response of lipid levels to postmenopausal estrogen use

The allelic variation of Apolipoprotein E (ApoE) influences serum lipid levels. Postmenopausal estrogen replacement therapy (ERT) has favorable effects on the serum lipid profile. We examined the effect of ApoE genotype on lipid response to ERT in 692 community-dwelling women aged 60 and older. ApoE genotypes were categorized into three groups: ApoE 2 (E2/E2+E2/E3, n=94), ApoE 3 (E3/E3, n=430), and ApoE 4 (E3/E4+E4/E4, n=142). Compared to 497 women not using ERT, 169 women currently using ERT were younger (P=0.01), had lower levels of total cholesterol (TC; P=0.10) and low-density lipoprotein (P<0.001), higher levels of high-density lipoprotein (HDL; P<0.001) and triglycerides (TG; P=0.009), and were more likely to have had a surgical menopause (P<0.001). No significant differences in body mass index, alcohol intake, physical activity, or cigarette smoking were found between current ERT users and nonusers (P>0.10). There was a significant interaction between ApoE 2 and ERT for HDL levels: women with ApoE 2 using ERT had the highest HDL levels, and women with ApoE 2 not using ERT had the lowest HDL levels (P=0.015). The unfavorable effect of ApoE 4 genotype on lipoproteins is not altered by HRT, but ApoE 2 genotype modulates the HDL-ERT association in older women.