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

Extracranial carotid artery atherosclerotic plaque and APOE polymorphisms: a systematic review and meta-analysis

Introduction

Carotid atherosclerotic plaque is an important independent risk factor for stroke. Apolipoprotein E (APOE) influences cholesterol levels and certain isoforms are associated with increased carotid atherosclerosis, though the exact association between APOE and carotid plaque is uncertain. The study aimed to evaluate the association between APOE and carotid plaque.

Methods

A systematic review was performed to retrieve all studies which examined the association between carotid plaque and APOE. This study was conducted in accordance with the PRISMA guidelines. Independent readers extracted the relevant data from each study including the type of imaging assessment, plaque definition, frequency of APOE E4 carrier status and type of genotyping. Meta-analyses with an assessment of study heterogeneity and publication bias were performed. Results were presented in a forest plot and summarized using a random-effects model.

Results

After screening 838 studies, 17 studies were included for systematic review. A meta-analysis of 5 published studies showed a significant association between ε4 homozygosity and carotid plaque [odds ratio (OR), 1.53; 95% CI, 1.16, 2.02; p = .003]. Additionally, there was a significant association between patients possessing at least one ε4 allele, heterozygotes or homozygotes, and carotid plaque (OR, 1.25; 95% CI, 1.03, 1.52; p = .03). Lastly, there was no association between ε4 heterozygosity and carotid plaque (OR, 1.08; 95% CI, 0.93, 1.26; p = .30).

Conclusion

APOE ε4 allele is significantly associated with extracranial carotid atherosclerotic plaque, especially for homozygous individuals.

Carotid Intima Media Thickness and Risk Factor for Atherosclerosis: Tohoku Medical Megabank Community-Based Cohort Study

AIM

We examined the association between the carotid intima medica thickness (cIMT) and risk factors for atherosclerosis based on the Japan Atherosclerosis Society 2022 Atherosclerosis Prevention Guideline.

METHODS

Using data from the Tohoku Medical Megabank Community-based Cohort Study, we performed a cross-sectional study that enrolled 13,366 participants (age ≥ 20 years) with an analysis of covariance to assess associations between cIMT and risk factors for atherosclerosis. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. Analysis was conducted in the model adjusted for age, sex, smoking status, drinking status, body mass index (BMI), systolic blood pressure (SBP), glycated hemoglobin (HbA1c), high-density lipoprotein-cholesterol (HDL-C), non-high-density lipoprotein-cholesterol (non-HDL-C), and height.

RESULTS

In this study cohort, the average age and cIMT were 57.3 (13.8) years and 0.61 (0.13) mm, respectively, which included 3,988 males (29.8%). Males had a higher cIMT than did the females. Age, height, BMI, SBP, HbA1c, and non-HDL-C were positively associated with cIMT. HDL-C was inversely associated with cIMT. Compared with never drinkers, current drinkers (≥ 46.0 g/day) had a significantly decreased cIMT.

CONCLUSIONS

The cIMT was associated with atherosclerosis risk factors including age, sex, BMI, SBP, HbA1c, non-HDL-C, and HDL-C, and adequate control of risks in high-risk individuals might be required to prevent atherosclerotic cardiovascular diseases.

Cross-Sectional Gene-Smoking Interaction Analysis in Relation to Subclinical Atherosclerosis-Results From the IMPROVE Study

BACKGROUND

Smoking is associated with carotid intima-media thickness (C-IMT). However, knowledge about how genetics may influence this association is limited. We aimed to perform nonhypothesis driven gene-smoking interaction analyses to identify potential genetic variants, among those included in immune and metabolic platforms, that may modify the effect of smoking on carotid intima-media thickness.

METHODS

We used baseline data from 1551 men and 1700 women, aged 55 to 79, included in a European multi-center study. Carotid intima-media thickness maximum, the maximum of values measured at different locations of the carotid tree, was dichotomized with cut point values ≥75, respectively. Genetic data were retrieved through use of the Illumina Cardio-Metabo- and Immuno- Chips. Gene-smoking interactions were evaluated through calculations of Synergy index (S). After adjustments for multiple testing, P values of <2.4×10-7 for S were considered significant. The models were adjusted for age, sex, education, physical activity, type of diet, and population stratification.

RESULTS

Our screening of 207 586 SNPs available for analysis, resulted in the identification of 47 significant gene-smoking synergistic interactions in relation to carotid intima-media thickness maximum. Among the significant SNPs, 28 were in protein coding genes, 2 in noncoding RNA and the remaining 17 in intergenic regions.

CONCLUSIONS

Through nonhypothesis-driven analyses of gene-smoking interactions, several significant results were observed. These may stimulate further research on the role of specific genes in the process that determines the effect of smoking habits on the development of carotid atherosclerosis.

Cardiorespiratory fitness decreases the odds for subclinical carotid plaques in apolipoprotein e4 homozygotes

Some studies suggest that being an apolipoprotein e4 (APOE e4) carrier increases the risk of atherosclerosis, and others suggest that cardiorespiratory fitness (CRF) could play a key role in atherosclerotic prevention. Our aim was to analyze the association of APOE e4 with carotid atherosclerosis and the association of CRF with atherosclerosis in APOE e4 carriers. A cross-sectional analysis based on a subsample of 90 participants in the Aragon Workers' Health Study was carried out. Ultrasonography was used to assess the presence of plaques in carotid territory; the submaximal Chester Step Test was used to assess CRF; and behavioral, demographic, anthropometric, and clinical data were obtained by trained personnel during annual medical examinations. APOE e4e4 participants were categorized into Low-CRF (VO_2max < 35 mL/kg/min) and High-CRF (VO_2max ≥ 35 mL/kg/min) groups. After adjusting for several confounders, compared with APOE e3e3, those participants genotyped as APOE e3e4 and APOE e4e4 showed an OR = 1.60 (95% CI 0.45, 5.71) and OR = 4.29 (95% CI 1.16, 15.91), respectively, for carotid atherosclerosis. Compared to Low-CRF APOE e4e4 carriers, the odds of carotid plaque detection were 0.09 (95% CI 0.008, 0.98) times lower among High-CRF APOE e4e4 carriers. The APOE e4e4 genotype was associated with increased carotid atherosclerosis. However, CRF is a modifiable factor that may be targeted by APOE e4e4 to decrease the elevation of atherosclerotic risk due to this genetic condition.

Effect of Apolipoprotein E ε4 Allele on the Progression of Carotid Atherosclerosis Through Apolipoprotein Levels

Background

Patients and methods

Results

Conclusion

Effect of alcohol on the central nervous system to develop neurological disorder: pathophysiological and lifestyle modulation can be potential therapeutic options for alcohol-induced neurotoxication

The central nervous system (CNS) is the major target for adverse effects of alcohol and extensively promotes the development of a significant number of neurological diseases such as stroke, brain tumor, multiple sclerosis (MS), Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS). Excessive alcohol consumption causes severe neuro-immunological changes in the internal organs including irreversible brain injury and it also reacts with the defense mechanism of the blood-brain barrier (BBB) which in turn leads to changes in the configuration of the tight junction of endothelial cells and white matter thickness of the brain. Neuronal injury associated with malnutrition and oxidative stress-related BBB dysfunction may cause neuronal degeneration and demyelination in patients with alcohol use disorder (AUD); however, the underlying mechanism still remains unknown. To address this question, studies need to be performed on the contributing mechanisms of alcohol on pathological relationships of neurodegeneration that cause permanent neuronal damage. Moreover, alcohol-induced molecular changes of white matter with conduction disturbance in neurotransmission are a likely cause of myelin defect or axonal loss which correlates with cognitive dysfunctions in AUD. To extend our current knowledge in developing a neuroprotective environment, we need to explore the pathophysiology of ethanol (EtOH) metabolism and its effect on the CNS. Recent epidemiological studies and experimental animal research have revealed the association between excessive alcohol consumption and neurodegeneration. This review supports an interdisciplinary treatment protocol to protect the nervous system and to improve the cognitive outcomes of patients who suffer from alcohol-related neurodegeneration as well as clarify the pathological involvement of alcohol in causing other major neurological disorders.

Alcohol consumption in relation to carotid subclinical atherosclerosis and its progression: results from a European longitudinal multicentre study

Background/Aim

The association between alcohol consumption and subclinical atherosclerosis is still unclear. Using data from a European multicentre study, we assess subclinical atherosclerosis and its 30-month progression by carotid intima-media thickness (C-IMT) measurements, and correlate this information with self-reported data on alcohol consumption.

Methods

Between 2002–2004, 1772 men and 1931 women aged 54–79 years with at least three risk factors for cardiovascular disease (CVD) were recruited in Italy, France, Netherlands, Sweden, and Finland. Self-reported alcohol consumption, assessed at baseline, was categorized as follows: none (0 g/d), very-low (0 − 5 g/d), low (> 5 to  ≤ 10 g/d), moderate (> 10 to ≤ 20 g/d for women,  > 10 to ≤ 30 g/d for men) and high (> 20 g/d for women, > 30 g/d for men). C-IMT was measured in millimeters at baseline and after 30 months. Measurements consisted of the mean and maximum values of the common carotids (CC), internal carotid artery (ICA), and bifurcations (Bif) and whole carotid tree. We used quantile regression to describe the associations between C-IMT measures and alcohol consumption categories, adjusting for sex, age, physical activity, education, smoking, diet, and latitude.

Results

Adjusted differences between median C-IMT values in different levels of alcohol consumption (vs. very-low) showed that moderate alcohol consumption was associated with lower C-IMT_max[− 0.17(95%CI − 0.32; − 0.02)], and Bif-IMT_mean[− 0.07(95%CI − 0.13; − 0.01)] at baseline and decreasing C-IMT_mean[− 0.006 (95%CI − 0.011; − 0.000)], Bif-IMT_mean[− 0.016(95%CI − 0.027; − 0.005)], ICA-IMT_mean[− 0.009(95% − 0.016; − 0.002)] and ICA-IMT_max[− 0.016(95%: − 0.032; − 0.000)] after 30 months. There was no evidence of departure from linearity in the association between alcohol consumption and C-IMT.

Conclusion

In this European population at high risk of CVD, findings show an inverse relation between moderate alcohol consumption and carotid subclinical atherosclerosis and its 30-month progression, independently of several potential confounders.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02220-5) contains supplementary material, which is available to authorized users.

Effect of ApoE4 Genotype on the Association Between Metabolic Phenotype and Subclinical Atherosclerosis in Postmenopausal Women

Metabolic profile and ApoE4 genotype have effects on coronary heart disease. We examined the interaction between these factors on subclinical atherosclerosis in postmenopausal women from the Early versus Late Intervention Trial with Estradiol (n = 497). Based on nine metabolic biomarkers (fasting blood glucose, insulin sensitivity, ketones, triglycerides, high-density lipoprotein, low-density lipoprotein, hemoglobin A1c, and blood pressure), K-means clustering categorized women into three distinct phenotypes: healthy, high blood pressure, and poor metabolic. ApoE4 genotype was classified as either ApoE4+ or ApoE4-. General linear models tested whether the cross-sectional association between metabolic phenotypes and common carotid intima media thickness (CIMT) differed by ApoE4 genotype. Mixed effects linear models evaluated the modifying role of ApoE4 genotype on the association of metabolic phenotype with CIMT progression over a median follow-up of 4.8 years. In cross-sectional analysis, ApoE4+ women with poor metabolic phenotype had the highest CIMT compared with all other groups. In ApoE4- women, CIMT was significantly lower in those classified as healthy compared with high blood pressure phenotype (p = 0.004). In ApoE4+ women, CIMT was significantly higher in those with poor metabolic phenotype compared with healthy (p = 0.0003) and high blood pressure (p = 0.001) phenotypes. These results indicate that metabolic phenotype had a negative effect on CIMT in women with ApoE4+ but not ApoE4- (interaction p = 0.001). These effects were not observed on CIMT progression in longitudinal analysis. In conclusion, ApoE4+ women are more likely to have higher levels of subclinical atherosclerosis if their metabolic phenotype is poor compared with ApoE4+ women without poor metabolic profile and ApoE4- women.

Critical Stenosis of the Internal Carotid Artery: Variability in Vertebral Artery Diameters and Areas of Cerebral Chronic Infarction in Computed Tomography

OBJECTIVES

We investigated unilateral and bilateral cervical internal carotid artery (ICA) stenosis according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST).

METHODS

We retrospectively investigated ICA stenosis on Head&Neck Computed Tomography Angiography (CTA); and their simultaneous brain computed tomography images were also evaluated. In unilateral ICA stenosis group (n=36), 17 of them had right ICA stenosis and 19 left ICA stenosis. In bilateral stenosis group, there were 24 patients. ICA stenosis was evaluated according to NASCET and ECST methods. We also evaluated vertebral artery dimension, plaque density and cerebral infarct (Cerebral kortex, white matter, basal ganglion-thalamus).

RESULTS

Unilateral ICA stenosis according to the NASCET was 70.64% to 73.68% (right-left) and according to the ECTS was 65.52% to 71.15% (right-left). For bilateral stenosis, ICA stenosis according to the NASCET was 67.70 to 67.91 (right-left); according to the ECTS was 62.45% to 62.15% (right-left). Vertebral artery dimensions were 3.26 to 3.72 mm (right-left) in unilateral ICA stenosis; and 3.52 to 3.71 mm (right-left) in bilateral ICA stenosis. In bilateral stenosis group, mixt plaque; and in unilateral stenosis group, hard plaque was detected. In unilateral stenosis, white matter and basal ganglion-thalamus infarcts; in bilateral ICA stenosis, cerebral cortical infarct was detected. Left-vertebral artery diameter increased in higher L-ECTS ICA stenosis (unilateral) group.

CONCLUSION

Increase in left vertebral artery diameter in unilateral L-ECTS ICA stenosis may be related to increase of the collateral flow by vertebral arteries to support brain blood-flow.

Alcohol Consumption and Common Carotid Intima-Media Thickness: The USE-IMT Study

Aims

Epidemiological evidence indicates a protective effect of light to moderate alcohol consumption compared to non-drinking and heavy drinking. Although several mechanisms have been suggested, the effect of alcohol on atherosclerotic changes in vessel walls is unclear. Therefore, we explored the relationship between alcohol consumption and common carotid intima media thickness, a marker of early atherosclerosis in the general population.

Methods

Individual participant data from eight cohorts, involving 37,494 individuals from the USE-IMT collaboration were used. Multilevel age and sex adjusted linear regression models were applied to estimate mean differences in common carotid intima-media thickness (CIMT) with alcohol consumption.

Results

The mean age was 57.9 years (SD 8.6) and the mean CIMT was 0.75 mm (SD 0.177). About, 40.5% reported no alcohol consumed, and among those who drank, mean consumption was 13.3 g per day (SD 16.4). Those consuming no alcohol or a very small amount (<5 g per day) had significantly lower common CIMT values than those consuming >10 g per day, after adjusting for a range of confounding factors.

Conclusion

In this large CIMT consortium, we did not find evidence to support a protective effect of alcohol on CIMT.

Apolipoprotein E Gene Polymorphism and Subclinical Carotid Atherosclerosis: The Northern Manhattan Study

BACKGROUND

Apolipoprotein E (APOE) polymorphism has previously been associated with carotid intima-media thickness (cIMT) in predominantly Caucasian populations. We sought to test the strength of the relationship between APOE-ε4 carrier status and subclinical atherosclerosis in a tri-ethnic population with a large Hispanic representation.

METHODS

We assessed the association between APOE polymorphism and cIMT and plaque burden among 1243 stroke-free individuals (mean age 69 years, 65% Hispanic, 18% black, 17% white) using a sequence of multivariable regression models.

RESULTS

After adjusting for demographics, vascular risk factors and plasma low-density lipoprotein (LDL) levels, APOE-ε4 carrier status was positively associated with cIMT (mean difference, .013 mm; 95% confidence interval, .003-.023 mm). The APOE-ε4 association with cIMT appeared to be segment-specific with greater differences in IMT between APOE-ε4 carriers and noncarriers in the common carotid artery (CCA, .014 mm) and bifurcation (.017 mm) than in the internal carotid artery (ICA) IMT (.007 mm). This relationship was not modified by race-ethnicity. Presence of diabetes modified the ε4-cIMT relationship in CCA (P = .045) and ICA (P = .046). APOE-ε4 carrier status was not associated with plaque presence or plaque area.

CONCLUSIONS

APOE-ε4 carriers had elevated cIMT independent of demographics and vascular risk factors including LDL levels. Diabetes was an effect modifier of the relationship between APOE-ε4 and IMT, such that ε4 carriers with diabetes had greater IMT in the CCA and ICA than those without diabetes. The APOE-IMT relationship was not modified by race-ethnicity.

Effect of exclusive cigarette smoking and in combination with waterpipe smoking on lipoproteins

Objective:

A significant increase in total cholesterol and LDL-C is well shown in tobacco users, as compared to non-tobacco users. The additive effects of waterpipe and cigarette smoking on LDL levels have not been studied. The study’s objective was to assess the correlation between cigarette smoking and LDL levels in Lebanese cigarette smokers and to check the interaction effect of waterpipe and cigarette smoking on LDL levels.

Methods:

This cross-sectional study was conducted between October 2016 and February 2017 in 4 different laboratories, enrolling 308 patients (188 non-smokers, 105 cigarette smokers, 15 previous smokers).

Results:

Current cigarette smoking (Beta = 25.57; p < 0.0001) was significantly associated with higher LDL levels and higher total cholesterol levels (Beta = 53.29; p < 0.0001) in exclusive cigarette smokers. Among current cigarette smokers who were current waterpipe smokers, a significant increase in LDL level was observed relative to current cigarette smokers who were not waterpipe smokers (Beta = 66.64 vs Beta = 37.37; p < 0.0001).

Conclusion:

Among Lebanese current cigarette smokers, LDL levels increased relative to nonsmokers, consistent with findings in other populations. In addition, among Lebanese current cigarette smokers, current waterpipe smoking might increase adverse lipid profiles associated with adverse coronary effects more than cigarette smoking alone. The direct cause responsible for these observed variations in our study remains unidentified, with the hope that future research will reveal it.

The Role of Cardiovascular Risk Factors and Stroke in Familial Alzheimer Disease

IMPORTANCE

The contribution of cardiovascular disease (CV) and cerebrovascular disease to the risk for late-onset Alzheimer disease (LOAD) has been long debated. Investigations have shown that antecedent CV risk factors increase the risk for LOAD, although other investigations have failed to validate this association.

OBJECTIVE

To study the contribution of CV risk factors (type 2 diabetes, hypertension, and heart disease) and the history of stroke to LOAD in a data set of large families multiply affected by LOAD.

DESIGN, SETTING, AND PARTICIPANTS

The National Institute on Aging Late-Onset Alzheimer Disease/National Cell Repository for Alzheimer Disease family study (hereinafter referred to as NIA-LOAD study) is a longitudinal study of families with multiple members affected with LOAD. A multiethnic community-based longitudinal study (Washington Heights-Inwood Columbia Aging Project [WHICAP]) was used to replicate findings. The 6553 participants in the NIA-LOAD study were recruited from 23 US Alzheimer disease centers with ongoing data collection since 2003; the 5972 WHICAP participants were recruited at Columbia University with ongoing data collection since 1992. Data analysis was performed from 2003 to 2015.

MAIN OUTCOMES AND MEASURES

Generalized mixed logistic regression models tested the association of CV risk factors (primary association) with LOAD. History of stroke was used for the secondary association. A secondary model adjusted for the presence of an apolipoprotein E (APOE) ε4 allele. A genetic risk score, based on common variants associated with LOAD, was used to account for LOAD genetic risk beyond the APOE ε4 effect. Mediation analyses evaluated stroke as a mediating factor between the primary association and LOAD.

RESULTS

A total of 6553 NIA-LOAD participants were included in the analyses (4044 women [61.7%]; 2509 men [38.3%]; mean [SD] age, 77.0 [9] years), with 5972 individuals from the WHICAP study included in the replication sample (4072 women [68.2%]; 1900 men [31.8%]; mean [SD] age, 76.5 [7.0] years). Hypertension was associated with decreased LOAD risk (odds ratio [OR], 0.63; 95% CI, 0.55-0.72); type 2 diabetes and heart disease were not. History of stroke conferred greater than 2-fold increased risk for LOAD (OR, 2.23; 95% CI, 1.75-2.83). Adjustment for APOE ε4 did not alter results. The genetic risk score was associated with LOAD (OR, 2.85; 95% CI, 2.05-3.97) but did not change the independent association of LOAD with hypertension or stroke. In the WHICAP sample, hypertension was not associated with LOAD (OR, 0.99; 95% CI, 0.88-1.11), whereas history of stroke increased the risk for LOAD (OR, 1.96; 95% CI, 1.56-2.46). The effect of hypertension on LOAD risk was also mediated by stroke in the NIA-LOAD and the WHICAP samples.

CONCLUSIONS AND RELEVANCE

In familial and sporadic LOAD, a history of stroke was significantly associated with increased disease risk and mediated the association between selected CV risk factors and LOAD, which appears to be independent of the LOAD-related genetic background.

Review: Lipids and stroke

Stroke is the third leading cause of death in adults. Although vascular disease is the prime contributor to its pathogenesis, dyslipidaemia is not unambiguously established as a risk factor for stroke in the same way that it is for coronary artery disease. Non-statin treatments of dyslipidaemia have not been shown clearly to help in preventing stroke. However, large clinical trials of treatment with statins over a number of years have demonstrated that these drugs decrease ischaemic stroke rates in persons at risk. Whether this reflects the efficacy of statins in lowering low density lipoprotein-cholesterol (LDL-c) concentrations alone or whether additional mechanisms may apply is not clear.

Twenty-year trajectories of alcohol consumption during midlife and atherosclerotic thickening in early old age: findings from two British population cohort studies

BACKGROUND

Epidemiological evidence indicates a protective effect of light-moderate drinking on cardiovascular disease and an increased risk for heavier drinking. Nevertheless, the effect of alcohol on atherosclerotic changes in vessel walls is disputed. Most previous studies have only looked at the cross-sectional relationship between alcohol and carotid intima media thickness (cIMT) - a surrogate marker of atherosclerosis. Single measurements of alcohol assume that alcohol exposure is stable and ignore the possible cumulative effects of harm, leading to possibly incorrect inferences.

METHODS

Data were retrieved from two UK population based cohort studies: the Whitehall II cohort of civil servants and the MRC National Survey of Health and Development (combined sample size of 5403 men and women). Twenty year-drinking trajectories during midlife were linked to measures of cIMT when participants were in early old age, and adjusted for age, sex, socioeconomic position, ethnicity and smoking.

RESULTS

Those who consistently drank heavily had an increased cIMT compared to stable moderate drinkers (pooled difference in cIMT 0.021 mm; 95 % CI 0.002 to 0.039), after adjustment for covariates. This was not detected in cross-sectional analyses. Former drinkers also had an increased cIMT compared to moderate drinkers (pooled difference in cIMT 0.021; 95 % CI 0.005 to 0.037). There were no appreciable differences in cIMT between non-drinkers and consistent moderate drinkers.

CONCLUSION

The drinking habits among adults during midlife affect the atherosclerotic process and sustained heavy drinking is associated with an increased cIMT compared to stable moderate drinkers. This finding was not seen when only using cross-sectional analyses, thus highlighting the importance of taking a life course approach. There was no evidence of a favourable atherosclerotic profile from stable moderate drinking compared to stable non-drinking.

Hypoxanthine induces cholesterol accumulation and incites atherosclerosis in apolipoprotein E-deficient mice and cells

Reactive oxygen species (ROS) generation during purine metabolism is associated with xanthine oxidase and uric acid. However, the direct effect of hypoxanthine on ROS generation and atherosclerosis has not been evaluated. Smoking and heavy drinking are associated with elevated levels of hypoxanthine. In this study, we investigated the role of hypoxanthine on cholesterol synthesis and atherosclerosis development, particularly in apolipoprotein E (APOE)‐deficient mice. The effect of hypoxanthine on the regulation of cholesterol synthesis and atherosclerosis were evaluated in Apoe knockout (KO) mice and cultured HepG2 cells. Hypoxanthine markedly increased serum cholesterol levels and the atherosclerotic plaque area in ApoeKO mice. In HepG2 cells, hypoxanthine increased intracellular ROS production. Hypoxanthine increased cholesterol accumulation and decreased APOE and ATP‐binding cassette transporter A1 (ABCA1) mRNA and protein expression in HepG2 cells. Furthermore, H₂O₂ also increased cholesterol accumulation and decreased APOE and ABCA1 expression. This effect was partially reversible by treatment with the antioxidant N‐acetyl cysteine and allopurinol. Hypoxanthine and APOE knockdown using APOE‐siRNA synergistically induced cholesterol accumulation and reduced APOE and ABCA1 expression. Hypoxanthine induces cholesterol accumulation in hepatic cells through alterations in enzymes that control lipid transport and induces atherosclerosis in APOE‐deficient cells and mice. These effects are partially mediated through ROS produced in response to hypoxanthine.

The potential applications of Apolipoprotein E in personalized medicine

Personalized medicine uses various individual characteristics to guide medical decisions. Apolipoprotein (ApoE), the most studied polymorphism in humans, has been associated with several diseases. The purpose of this review is to elucidate the potential role of ApoE polymorphisms in personalized medicine, with a specific focus on neurodegenerative diseases, by giving an overview of its influence on disease risk assessment, diagnosis, prognosis, and therapy. This review is not a systematic inventory of the literature, but rather a summary and discussion of novel, influential and promising works in the field of ApoE research that could be valuable for personalized medicine. Empirical evidence suggests that ApoE genotype informs pre-symptomatic risk for a wide variety of diseases, is valuable for the diagnosis of type III dysbetalipoproteinemia, increases risk of dementia in neurodegenerative diseases, and is associated with a poor prognosis following acute brain damage. ApoE status appears to influence the efficacy of certain drugs, outcome of clinical trials, and might also give insight into disease prevention. Assessing ApoE genotype might therefore help to guide medical decisions in clinical practice.

Prevalence and association of lifestyle factors with extracranial carotid atherosclerosis in non-cardioembolic anterior circulation strokes in adult males less than 50 years: One year cross-sectional study

BACKGROUND

Data is scarce on prevalence of extracranial carotid atherosclerosis (ECA) in strokes <50 years and its association with lifestyle factors.

OBJECTIVE

Study role of (a) ECA in non-cardio-embolic anterior circulation young strokes, and (b) smoking and alcohol in ECA.

MATERIALS AND METHODS

Cardiovascular risk factors and evidence of ECA on carotid doppler ultrasound (CDUS) was evaluated in an one-year preliminary cross-sectional study of consecutive strokes between 20 years and 49 years. Females were excluded.

RESULTS

There were 46 male strokes (mean age 38.26 yrs), 17.39% had hypertension, 2.23% had coronary artery disease; none was diabetic. Tobacco users and alcohol consumers were 24/46 (52.17%) cases each. ECA was found in 14/46 (30.44%) cases. Seven of these 14 (50%) i.e., 7/46 cases (15.21%) had carotid occlusion, four had <50%, three had >70% stenosis. 'Smoking and smokeless tobacco use' was found in 71.42% (10/14) symptomatic carotid lesions compared to 43.75% (14/32) strokes without carotid lesions. Prevalence odds ratio for tobacco use and ECA was 3.21 (95% CI: 0.83-12.44) while that of alcohol and ECA was 1.33 (95% CI: 0.38-4.72).

CONCLUSION

Prevalence of ECA in strokes <50 years was high due to lifestyle factors which predispose to atherosclerosis at younger age.

"Addressing the impact of stroke risk factors in a case control study in tertiary care hospitals": a case control study in Tertiary Care Hospitals of Peshawar, Khyber Phukhtoonkhwa (KPK) Pakistan

Background

Stroke was the second most common cause of death worldwide in 2004, resulting in 5.7 million deaths. This case controlled study was conducted in Tertiary care hospitals of Peshawar, KPK Pakistan about common risk factors of stroke and the impact of these risk factors.

Method

Study was done at Government Tertiary Care Hospitals of Peshawar namely Khyber Teaching Hospital (KTH), Lady Reading Hospital (LRH) and Hayatabad Medical Complex (HMC).The hospital based case–control study included 50 cases (stroke patients) and 100 controls (non-stroke patients). This study was accomplished from 24th April 2012 to October 2012 in tertiary care hospitals of Peshawar. A proper questionnaire was used to collect data from all the cases and controls, which was recorded in the form of tables and graphs. The risk factors studied were Hypertension, Smoking, diabetes, sedentary lifestyle, cardiac problems, B.M.I, diet, stress and family history of stroke. Anthropometric (weight, height, body mass index) measurements were done on all patients. For determination of association and impact of these risk factors, analyses were performed by calculation of Chi-Square test and confidence interval using SPSS version 16 program.

Results

Comparing the cases with controls, hypertension (p = 0.000), sedentary life style (p = 0.000), cardiac problems (p = 0.009), diabetes mellitus (p = 0.010), smoking (p = 0. 042) were significant risk factors whereas B.M.I (p = 0. 393), stress (p = 0.705), family history of stroke (p = 0.729), diet (p = 0.908), were not found to be statistically significant risk factors. The most significant risk factor was systemic hypertension (OR = 4.16) followed by sedentary life style (OR = 3.60), cardiac problems (OR = 2.74) diabetes (OR = 2.49) and smoking (OR = 2.05).

Conclusion

Hypertension, Smoking, diabetes, sedentary lifestyle and cardiac problems have strong correlations and association with Stroke and are the major risk factors of stroke. Prevention of these risk factors can lead to decrease in the incidence of stroke. B.M.I, diet, stress and family history of stroke had no significant association.

The association between apolipoprotein E gene polymorphisms and essential hypertension: a meta-analysis of 45 studies including 13,940 cases and 16,364 controls

The apolipoprotein E single-nucleotide polymorphisms are among the potential candidate genes that may serve as modulators in susceptibility to essential hypertension. In an effort to clarify earlier inconclusive results, we performed a meta-analysis of population-based case-control genetic association studies. Random-effects methods were applied on summary data in order to combine the results of the individual studies. We identified in total 45 studies, including 13 940 hypertensive cases and 16 364 controls. The contrast of E4 carriers versus non-carriers yielded an overall odds ratio (OR) of 1.16 (95% confidence interval (CI): 1.02, 1.31), whereas the contrast of E4 allele versus the others in a subtotal of 6617 cases and 7330 controls, yielded an OR of 1.39 (95% CI: 1.12, 1.72). There was moderate evidence of publication bias in both contrasts, which was eliminated after excluding studies not in Hardy-Weinberg equilibrium. Subgroup analyses revealed that significant estimates arose from studies on Asian populations, as opposed to the Caucasian ones. Furthermore, no evidence of publication bias was demonstrated in the comparisons within this subgroup. Our results are consistent with recent meta-analyses but show that the association is weaker than that has been previously demonstrated. Further studies are needed in order to fully address questions about the etiological mechanism of the particular association, as well as to study the effect in populations of African descent.

Alcohol consumption and carotid atherosclerosis in China: the Cardiovascular Risk Survey

AIM

The relationship between alcohol consumption and carotid atherosclerosis has been reported in some epidemiological studies, but the results were conflicting. We investigated the association between alcohol intake and carotid atherosclerosis in the Han, Uygur, and Kazakh populations in Xinjiang in western China.

METHODS AND RESULTS

The study population sample comprised 13,037 Chinese people (5277 Han, 4572 Uygur, and 3188 Kazakh) aged ≥35 years who participated in a cardiovascular risk survey between June 2007 and March 2010. Daily consumption of alcohol was determined by the number and frequency of alcoholic beverages consumed. Carotid-artery parameters, including common carotid artery intima-media thickness (CCA-IMT) and carotid plaques were measured using high-resolution B-mode ultrasonography. In the Han and Kazakh populations, CCA-IMT as a function of alcohol consumption was depicted as a J-shaped curve with a nadir for the alcohol-intake category of 20-29.9 g/day; In the Uygur population, a similar curve with a nadir of 30-49.9 g/day was observed. With respect to the prevalence of carotid plaques, we also observed similar curves in the Han and Kazakh populations, but not in the Uygur population. After adjustment for age, sex, blood pressure, body mass index, and smoking status, as well as levels of glucose, total cholesterol, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol, the J-shaped curves remained.

CONCLUSIONS

Our results indicated that alcohol consumption was associated with carotid atherosclerosis and that moderate drinking had an inverse association with carotid atherosclerosis. However, the definition of moderate drinking could be different in Han, Uygur, and Kazakh populations.

Structural equation modeling of gene-environment interactions in coronary heart disease

Coronary heart disease (CHD) is a complex disease, which is influenced not only by genetic and environmental factors but also by gene-environment (GE) interactions in interconnected biological pathways or networks. The classical methods are inadequate for identifying GE interactions due to the complex relationships among risk factors, mediating risk factors (e.g., hypertension, blood lipids, and glucose), and CHD. Our aim was to develop a two-level structural equation model (SEM) to identify genes and GE interactions in the progress of CHD to take into account the causal structure among mediating risk factors and CHD (Level 1), and hierarchical family structure (Level 2). The method was applied to the Framingham Heart Study (FHS) Offspring Cohort data. Our approach has several advantages over classical methods: (1) it provides important insight into how genes and contributing factors affect CHD by investigating the direct, indirect, and total effects; and (2) it aids the development of biological models that more realistically reflect the complex biological pathways or networks. Using our method, we are able to detect GE interaction of SERPINE1 and body mass index (BMI) on CHD, which has not been reported. We conclude that SEM modeling of GE interaction can be applied in the analysis of complex epidemiological data sets.

Alcohol consumption and ankle-to-brachial index: results from the Cardiovascular Risk Survey

Background and Methodology

A low ankle-to-brachial index (ABI) is a strong correlate of cardiovascular disease and subsequent mortality. The relationship between ABI and alcohol consumption remains unclear. Data are from the Cardiovascular Risk Survey (CRS), a multiple-ethnic, community-based, cross-sectional study of 14 618 Chinese people (5 757 Hans, 4 767 Uygurs, and 4 094 Kazakhs) aged 35 years and over at baseline from Oct. 2007 to March 2010. The relationship between alcohol intake and ABI was determined by use of analysis of covariance and multivariable regressions.

Principal Findings

In men, alcohol consumption was significantly associated with ABI (P<0.001). After adjusted for the confounding factors, such as age, sex, ethnicity, body mass index, smoking, work stress, diabetes, and fasting blood glucose, the difference remained significant (P<0.001); either the unadjusted or multivariate-adjusted odds ratio (OR) for peripheral artery disease (PAD) was significantly higher in men who consumed >60.0 g/d [OR  = 3.857, (95% CI: 2.555–5.824); OR = 2.797, (95% CI: 1.106–3.129); OR = 2.878, (95% CI: 1.215–4.018); respectively] and was significantly lower in men who consumed 20.1–40.0 g/d [OR  = 0.330, (95% CI: 0.181–0.599); OR = 0.484, (95% CI: 0.065–0.894); OR = 0.478, (95% CI: 0.243–1.534); respectively] and 40.1–60.0 g/d [OR  = 0.306, (95% CI: 0.096–0.969); OR = 0.267, (95% CI: 0.087–0.886); OR = 0.203, (95% CI: 0.113–0.754); respectively] compared with never drinking, respectively (all P<0.01). Neither in unadjusted nor in multivariate-adjusted model was the association between ABI and alcohol consumption significant (all P>0.05) in women. Similarly, PAD was not correlated with alcohol intake in women (all P>0.05).

Conclusions/Significance

Our results indicated that in Chinese men, alcohol consumption was associated with peripheral artery disease, and consumption of less than 60 g/d had an inverse association with peripheral atherosclerosis whereas consumption of 60 g/d or more had a positive association.

Smoking and atherosclerotic cardiovascular disease: Part IV: Genetic markers associated with smoking

Genes influence smoking behavior, affect the metabolism of nicotine and specific chemicals produced during combustion, and enhance (or diminish) pathomechanistic pathways associated with the atherogenic potential of smoking, including oxidative stress, its inflammatory burden or procoagulant potential. Genome-wide association studies have revolutionized the search for new functional genetic markers with ever increasing marker density and the precision in identifying new genetic loci without the need for prior knowledge of functional pathways. Nevertheless, the statistical challenge remains to identify the few true positives, the need for replication of findings and the tedious work of identifying functional genetic variants and their mode of action. Genetic variation within a gene or in areas of the genetic code that control the expression of such a gene is far from being understood. Major advances include the detection of large-scale copy-number variants in the human genome and the demonstration of the decisive role of ‘miRNA’ in controlling gene expression. The role of the genomic methylation pattern in controlling the transcription of the underlying genetic sequence and its role in interacting with environmental influences have yet to be explored in depth. Although candidate genes and their genetic variants have been associated with atherosclerosis and cigarette smoking, a major breakthrough has still to be made.

Alcohol consumption and carotid artery structure in Korean adults aged 50 years and older

BACKGROUND

Epidemiologic studies of the association between alcohol consumption and carotid artery structure have reported conflicting results. We investigated the association between alcohol consumption and carotid atherosclerosis by evaluating the effects of alcohol intake on carotid artery enlargement.

METHODS

The study population consisted of 4302 community-dwelling Koreans (1577 men and 2725 women) aged 50 years and over. All the subjects had participated in the baseline survey of the Dong-gu Study conducted between 2007 and 2008. Daily alcohol consumption was determined by the number and frequency of alcoholic beverages consumed. We measured common carotid artery intima-media thickness (CCA-IMT), common carotid and bulb IMT (CB-IMT), carotid plaques, and the diameter of the common carotid artery (CCA-diameter) using high-resolution B-mode ultrasonography. We used analysis of covariance and multiple logistic regressions to determine the relationship between alcohol consumption and carotid artery parameters.

RESULTS

CCA-IMT and CB-IMT were negatively correlated with alcohol consumption after controlling for cardiovascular risk factors in men (p for linear trend = 0.009 and = 0.038, respectively). The multivariate-adjusted odds ratio (OR) for carotid plaques was significantly higher in men who consumed >40.0 g/d (OR = 1.81, 95% CI = 1.13-2.91), although a significant positive correlation was observed between alcohol consumption and carotid plaques (p for linear trend = 0.027). Neither carotid IMT nor carotid plaques were correlated with alcohol intake in women. Alcohol intake was positively correlated with CCA-diameter adjusted for carotid IMT and plaques in the multivariate-adjusted model in both sexes (p for linear trend <0.001 for men and 0.020 for women).

CONCLUSION

The results of our study indicate that alcohol consumption is inversely related to carotid IMT and positively related to carotid plaques in men, but not women. However, alcohol intake is positively associated with CCA-diameter in both men and women. Additional large population-based prospective studies are needed to confirm the effects of alcohol consumption on carotid artery structure.

Cross-sectional and longitudinal association of cigarette smoking with carotid atherosclerosis in Chinese adults

OBJECTIVE

To assess the cross-sectional and longitudinal association of cigarette smoking with carotid atherosclerosis in middle-aged and older Chinese adults.

METHODS

The study population consisted of 1132 residents in Beijing (748 women and 384 men) aged 35 to 64 years. Information on baseline smoking characteristics, including smoking status and pack-years was collected in 1993-1994. The cohort was resurveyed in 2002 and common carotid artery intima-media thickness (CCA-IMT) and carotid plaques were measured by B-mode ultrasound.

RESULTS

The multivariable-adjusted mean CCA-IMT at resurvey was significantly associated with smoking status at both resurvey and baseline, and was 0.72 mm for consistent current smokers, 0.71 mm for former and inconsistent smokers, and 0.70 mm for consistent never smokers at both surveys, respectively (p-trend<0.01). The multivariable-adjusted odds ratio [OR, 95% confidence interval (CI)] of having carotid plaques was 1.5 (1.0-2.1) for consistent current smokers vs consistent never smokers. In addition, there was a significant dose-response relationship between baseline smoking pack-years and multivariable-adjusted mean CCA-IMT and risk of having carotid plaques at resurvey.

CONCLUSION

Smoking is associated with carotid atherosclerosis in middle-aged and older Chinese adults both cross-sectionally and longitudinally. Smoking cessation may play a significant role in prevention and control of cardiovascular diseases in China.

Polymorphisms of the methylenetetrahydrofolate reductase, vascular endothelial growth factor, endothelial nitric oxide synthase, monocyte chemoattractant protein-1 and apolipoprotein E genes are not associated with carotid intima-media thickness

BACKGROUND

Single nucleotide polymorphisms in the 5,10-methylenetetrahydrofolate reductase (MTHFR), vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), monocyte chemoattractant protein-1 (MCP-1) and apolipoprotein E (ApoE) genes appear to be a genetic risk factor for atherosclerosis. Common carotid intima-media thickness (cIMT) provides information on the severity of atherosclerosis.

OBJECTIVE

To investigate the relationship between cIMT and gene polymorphisms associated with atherosclerosis in Turkish patients with coronary artery disease (CAD).

METHODS

Sixty-two patients with angiographically diagnosed stable CAD were divided into two groups according to their cIMT values (group 1: n=35, cIMT of 1 mm or greater; group 2: n=27, cIMT of less than 1 mm). MTHFR 677 C/T, VEGF --460 C/T, eNOS 894 G/T, MCP-1 --2518 A/G and ApoE (E2, E3 and E4) gene polymorphisms (where A is adenine, C is cytosine, G is guanine and T is thymine) were analyzed by polymerase chain reaction and restriction fragment length polymorphism. Evaluations of cardiovascular risk factors and coronary atherosclerotic lesions were performed in all patients. Serum homocysteine and high-sensitivity C-reactive protein were measured and compared between the two groups.

RESULTS

Serum high-sensitivity C-reactive protein (P=0.04) and homocysteine (P=0.006) levels were higher in group 1 than in group 2. The ratio of multivessel CAD and previous myocardial infarction was significantly higher in group 1 than in group 2 (P=0.014). In the study population, no significant difference in cIMT was observed according to the polymorphisms studied. Only hyperhomocysteinemia (OR 1.17 [95% CI 1.01 to 1.35], P=0.033) and previous myocardial infarction (OR 3.76 [95% CI 1.10 to 12.81], P=0.034) maintained a significant correlation with cIMT on multiple logistic regression analysis.

CONCLUSION

cIMT is increased in patients with hyperhomocysteinemia, inflammation and extended CAD. MTHFR 677 C/T, VEGF --460 C/T, eNOS 894 G/T, MCP-1 --2518 A/G and ApoE single nucleotide polymorphisms were not associated with increased cIMT.

Binge drinking and the progression of atherosclerosis in middle-aged men: an 11-year follow-up

OBJECTIVE

There is limited knowledge on drinking patterns and the progression of atherosclerosis. Previous studies have shown conflicting results between alcohol consumption and atherosclerotic progression. We investigated the association between the pattern of binge drinking and the 11-year progression of carotid atherosclerosis in a population-based sample of middle-aged men.

METHODS AND RESULTS

This study is a part of the FinDrink Study, based on the Kuopio Ischemic Heart Disease Risk Factor Study. We investigated the effect of drinking patterns on the changes in maximum and mean intima-media thickness, including changes in maximum plaque height in 751 participants as measured by carotid ultrasound. The increased atherosclerosis progression was statistically significant among those men with binge drinking of >or=6 drinks per session (22.4% of total number of participants) using different covariates in different models according to the mean increase in maximum intima-media thickness (Model 1, p=0.008; Model 2, p=0.031, Model 3, p=0.037) and the mean increase in maximum plaque height (Model 1, p=0.002; Model 2, p=0.012, Model 3, p=0.017).

CONCLUSION

Our study shows that binge drinking was associated with an increased atherosclerosis progression during an 11-year follow-up in middle-aged men, independent of the total alcohol consumption.

Impact of apoE genotype on oxidative stress, inflammation and disease risk

Although in developing countries an apolipoprotein E4 (apoE4) genotype may offer an evolutionary advantage, as it has been shown to offer protection against certain infectious disease, in Westernised societies it is associated with increased morbidity and mortality, and represents a significant risk factor for cardiovascular disease, late-onset Alzheimer's disease and other chronic disorders. ApoE is an important modulator of many stages of lipoprotein metabolism and traditionally the increased risk was attributed to higher lipid levels in E4 carriers. However, more recent evidence demonstrates the multifunctional nature of the apoE protein and the fact that the impact of genotype on disease risk may be in large part due to an impact on oxidative status or the immunomodulatory/anti-inflammatory properties of apoE. An increasing number of studies in cell lines, targeted replacement rodents and human volunteers indicate higher oxidative stress and a more pro-inflammatory state associated with the epsilon4 allele. The impact of genotype on the antioxidant and immunomodulatory/anti-inflammatory properties of apoE is the focus of the current review. Furthermore, current information on the impact of environment (diet, exercise, smoking status, alcohol) on apoE genotype-phenotype associations are discussed with a view to identifying particular lifestyle strategies that could be adapted to counteract the 'at-risk' E4 genotype.

A common VLDLR polymorphism interacts with APOE genotype in the prediction of carotid artery disease risk

The genetic factors associated with carotid artery disease (CAAD) are not fully known. Because of its role in lipid metabolism, we hypothesized that common genetic variation in the very low density lipoprotein receptor (VLDLR) gene is associated with severe CAAD (>80% stenosis), body mass index (BMI), and lipid traits in humans. VLDLR was resequenced for variation discovery in 92 subjects, and single nucleotide polymorphisms (tagSNPs) were chosen for genotyping in a larger cohort (n = 1,027). Of the 17 tagSNPs genotyped, one tagSNP (SNP 1226; rs1454626) located in the 5' flanking region of VLDLR was associated with CAAD, BMI, and LDL-associated apolipoprotein B (apoB). We also identified receptor-ligand genetic interactions between VLDLR 1226 and APOE genotype for predicting CAAD case status. These findings may further our understanding of VLDLR function, its ligand APOE, and ultimately the pathogenesis of CAAD in the general population.

Effect of alcohol and tobacco smoke on mtDNA damage and atherogenesis

Environmental tobacco smoke (ETS) exposure and alcohol (EtOH) consumption often occur together, yet their combined effects on cardiovascular disease development are currently unclear. A shared feature between ETS and EtOH exposure is that both increase oxidative stress and dysfunction within mitochondria. The hypothesis of this study was that simultaneous EtOH and ETS exposure will significantly increase atherogenesis and mitochondrial damage compared to the individual effects of either factor (ETS or EtOH). To test this hypothesis, apoE(-/-) mice were exposed to EtOH and/or ETS singly or in combination for 4 weeks and compared to filtered air, nonalcohol controls. Atherosclerotic lesion formation (oil red O staining of whole aortas), mitochondrial DNA (mtDNA) damage, and oxidant stress were assessed in vascular tissues. Combined exposure to ETS and EtOH had the greatest impact on atherogenesis, mtDNA damage, and oxidant stress compared to filtered air controls, alcohol, or ETS-exposed animals alone. Because moderate EtOH consumption is commonly thought to be cardioprotective, these studies suggest that the potential influence of common cardiovascular disease risk factors, such as tobacco smoke exposure or hypercholesterolemia, on the cardiovascular effects of alcohol should be considered.

Apolipoprotein E epsilon4 genotype is independently associated with increased intima-media thickness in a recessive pattern

Polymorphisms in the apolipoprotein E (Apo E) gene have been associated with lipid levels, carotid intima media thickness (CCA-IMT), inflammation and cardiovascular disease (CVD). Earlier findings suggested an association of the Apo E alleles with increased CCA-IMT following a recessive pattern. Whether associations might be independent of C-reactive protein (CRP), lipid levels and other CVD risk factors is not known. We investigated the relationships between Apo E (epsilon2, epsilon3 and epsilon4 alleles) and CCA-IMT, measured by B-mode ultrasound, in dominant and recessive models in a community-based sample of 437 men 75 years of age. In men homozygous for the epsilon4 allele CCA-IMT was significantly increased by 0.13 mm to 0.86 +/- 0.16 mm compared to 0.73 +/- 0.19 mm in non- epsilon4-carriers (P = 0.0012) and 0.73 +/- 0.21 mm in epsilon4 heterozygous (P = 0.0044) in unadjusted recessive models. The association between Apo E epsilon4 genotype and CCA-IMT was independent of Apo E epsilon2 and Apo E epsilon3 alleles, CRP, lipid variables (TG, LDL, HDL) and other CVD risk factors (smoking, hypertension, body mass index, diabetes) (P = 0.018). No relations between Apo E genotype and CCA-IMT were observed in dominant models. No significant associations between the Apo E epsilon2 and epsilon3 alleles and CCA-IMT were found. In this study, men homozygous with the ApoE epsilon4 allele had thicker CCA-IMT, independently of Apo E epsilon2 and epsilon3 alleles, CRP, lipid variables (TG, LDL, HDL) and other CVD risk factors (smoking, hypertension, body mass index, diabetes), suggesting CCA-IMT to be modified by the ApoE epsilon4 genotype in a recessive pattern.

Circle of Willis atherosclerosis: association with Alzheimer's disease, neuritic plaques and neurofibrillary tangles

The role of intracranial atherosclerosis in Alzheimer's disease (AD) has been a subject of debate since the first decade of the last century. The initial "vascular hypothesis" of AD was rejected after a series of mid-twentieth century gross anatomical postmortem studies that showed an inconstant relationship between intracranial atherosclerosis and senile dementia. These early studies did not utilize statistical methods, however, and the investigators did not appear to consider the possibility that intracranial atherosclerosis might have a probabilistic, rather than an absolute, effect on AD risk. Recent studies by three independent groups have found a significant statistical association between postmortem measures of circle of Willis atherosclerosis and AD. The present study was undertaken to further address the validity of this association in a large autopsy series, including cases diagnosed neuropathologically with vascular dementia (VaD) and non-AD dementias. Postmortem gross anatomical grading of circle of Willis atherosclerosis was performed in 397 subjects classified by neuropathological diagnosis, including 92 non-demented elderly controls, 215 with AD, 30 with VaD and 60 with non-AD dementias. Circle of Willis atherosclerosis was more severe in subjects with AD and VaD than in control subjects, while it was equivalent between control subjects and subjects with non-AD dementias. Increasing atherosclerotic grade increased the odds ratios (OR) for the diagnoses of both AD and VaD and also increased the ORs for both increased neuritic plaque density and higher Braak neurofibrillary tangle stage. The significance of these associations was retained after consideration of the effects of age, gender and the apolipoprotein E-epsilon4 allele. The results suggest that the statistical association between intracranial atherosclerosis and AD is not an artifact of diagnostic misclassification or of unequal distribution of the apolipoprotein E-epsilon4 allele.

New Insight Into the Association of Apolipoprotein E Genetic Variants With Carotid Plaques and Intima-Media Thickness

BACKGROUND AND PURPOSE

Carotid plaques and elevated carotid artery intima-media thickness (IMT) are major predictors of vascular morbidity and mortality. Our aim was to test their association with 2 polymorphisms of the apolipoprotein E (apoE) gene, epsilon and -219G/T.

METHODS

The study was performed on 5856 subjects aged > or =65 years recruited from the French population for the Three-City Study. Carotid ultrasound examination included an assessment of atherosclerotic plaques in the extracranial carotid arteries and a measurement of IMT in the common carotid arteries (CCA) at a site free of plaques. The genetic association was tested using genotype and haplotype analyses.

RESULTS

In a multivariate analysis including both polymorphisms and vascular risk factors, carotid plaques were more frequent in epsilon4 homozygotes (adjusted odds ratio=2.12, 95% CI=1.27 to 3.53) and less frequent in epsilon2 carriers (adjusted odds ratio=0.79, 95% CI=0.66 to 0.95) compared with epsilon3 homozygotes. Adjusting for and stratifying on lipid levels did not modify these results. CCA-IMT was higher in carriers of the epsilon34 genotype (mean CCA-IMT=0.744 mm versus 0.732 mm for the epsilon33 genotype, P=0.002), but the association disappeared after excluding subjects with carotid plaques. No association was found between the -219 polymorphism and either carotid plaques or CCA-IMT, and there was no interaction or cis-effect between -219 and epsilon.

CONCLUSIONS

This study, conducted on a large population cohort of French elderly, demonstrated that carotid plaques were significantly associated with the apoE epsilon polymorphism independently of the -219 polymorphism and vascular risk factors, in particular lipid levels.

Smoking status and common carotid artery intima-medial thickness among middle-aged men and women based on ultrasound measurement: a cohort study

Background

Cigarette smoking is an established causal factor for atherosclerosis. However, the smoking effect on different echogenic components of carotid arterial wall measured by ultrasound is not well elucidated.

Methods

Middle-aged men and women who had IMT measurement ≥ 0.7 mm at baseline and follow-up were included (N = 413, age 40–60 years at baseline in 1995). Intima-media thickness of common carotid artery (CCA-IMT) and its components (echogenic and echolucent layers) were measured at baseline and in the follow-up examination 3 years later. IMT and its components were compared across current, former and never smokers. Individual growth models were used to examine how smoking status was related to the baseline and progression of overall IMT and IMT components.

Results

For both men and women, current smoking was associated with thicker echogenic layer than never smokers; former smokers exhibited thinner echogenic layer than current smokers after adjustment for cigarette pack-years. Among women, current smoking was also associated with a thinned echolucent layer that resulted in a non-significant overall association of current smoking with IMT for women.

Conclusion

Cigarette smoking is associated with carotid artery morphological changes and the association is sex-dependent. The atherogenic effect of smoking appears to be partly reversible among former smokers. IMT measurement alone may not be adequate to detect carotid atherosclerosis associated with cigarette smoking among middle-age women.

QTL-specific genotype-by-smoking interaction and burden of calcified coronary atherosclerosis: the NHLBI Family Heart Study

BACKGROUND

Calcified coronary plaque (CCP) is a complex trait influenced by both genes and environment, and plausibly an interaction between the two. Because the familial aggregation of CCP has been demonstrated and smoking is a significant, independent predictor of CCP, we assessed the evidence for genotype-by-smoking interaction and conducted linkage analysis of quantitative Agatston CCP scores in participants of the NHLBI Family Heart Study (FHS).

METHODS

During standardized clinical exams smoking habits were ascertained and CCP was quantified with cardiac computed tomography (CT). Among 4387 relationship pairs from 2128 Caucasian examinees variance component analysis was implemented in SOLAR to examine: (1) additive genotype-by-smoking status interaction using a variance component approach; (2) linkage analysis in the full sample and among smoking subsets defined by individual smoking exposure; (3) QTL-specific genotype-by-smoking interaction in the regions that appeared to differentiate between smoking strata.

RESULTS

The prevalence of CCP (and median Agatston score) was 75% (184.6) in men and 48% (51.0) in women. We detected four genome-wide significant logarithm of odds (LOD) scores in samples stratified by individual smoking exposure: chromosome 4 at 122cM (nearest marker D4S2297; robust adjusted LOD=3.1; q=0.053), chromosome 6 at 99cM (nearest marker D6S1056; robust adjusted LOD=3.3; q=0.053), chromosome 11 at 19cM (nearest marker D11S199; robust adjusted LOD=4.0; q=0.02) and chromosome 13 at 77cM (nearest marker D13S892; robust adjusted LOD=3.1; q=0.053). Additive and QTL-specific genotype-by-smoking interaction was detected on chromosomes 4, 6, 11 and 13; all P<0.05. Three of the four QTLs identified in this report have been previously linked to atherosclerosis and harbor interesting candidate genes.

CONCLUSIONS

These findings demonstrate the importance of considering complex interactions in the search for genes that influence the pathogenesis of CCP.

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.

Apolipoprotein E polymorphisms predict low density lipoprotein cholesterol levels and carotid artery wall thickness but not incident coronary heart disease in 12,491 ARIC study participants

Elevated levels of low density lipoprotein (LDL) cholesterol is a well-established risk factor for cardiovascular disease, and recent advancements have provided evidence that carotid artery intima-media thickness (IMT) is associated with increased occurrence of cardiovascular events. Apolipoprotein E (ApoE) has been widely studied in regard to its role in lipid transport and metabolism, but the role that ApoE genetic variation plays in relation to carotid artery IMT and risk of incident coronary heart disease remains a subject of debate. In 1987-2001, the authors examined the effect of each ApoE allele (epsilon2, epsilon3, epsilon4) on LDL cholesterol and carotid IMT, as well as the association with coronary heart disease risk, in 12,491 participants of the US Atherosclerosis Risk in Communities Study. ApoE epsilon2, epsilon3, and epsilon4 allele frequencies were determined, respectively, in Whites (0.08, 0.77, 0.15) and African Americans (0.11, 0.67, 0.22). These alleles did not predict incident coronary heart disease in either racial group. The ApoE epsilon2 allele was associated with lower LDL cholesterol and the epsilon4 allele with higher LDL cholesterol in both Whites and African Americans. The ApoE epsilon2 and epsilon4 alleles were associated with carotid IMT measures in both racial groups, but, after adjusting for lipid parameters, only the epsilon4 allele was associated with carotid IMT measures in African Americans.

Is alcohol consumption associated with calcified atherosclerotic plaque in the coronary arteries and aorta?

BACKGROUND

The goal was to investigate the relation of alcohol consumption to the presence of calcified atherosclerotic plaque in the coronary arteries (CAC) and aorta. Previous results have been conflicting, showing increases, decreases, or no effect of alcohol on risk of calcified plaque.

METHODS

We evaluated the relation of alcohol intake to presence of CAC and calcified plaque in the aorta among 3166 white and African American subjects from the NHLBI Family Heart Study who underwent cardiac computed tomography scans.

RESULTS

With adjustments for age, race, study center, body mass index, hyperglycemia/diabetes, hypertension, and smoking, odds ratios (and 95% CI) for CAC scores >100 in nondrinkers and consumers of 1 to 3, 4 to 7, 8 to 14, and >14 drinks per week were 1.0, 0.8 (0.4, 1.3), 1.1 (0.6, 1.9), 0.9 (0.5, 1.5), and 1.5 (0.9, 2.5), respectively, for men and 1.0, 0.9 (0.5, 1.6), 1.3 (0.8, 2.3), 1.3 (0.7, 2.2), and 2.1 (0.8, 5.9) for women. Sensitivity analyses with other cut-points for calcification gave similar results. Analyses of alcohol and aortic calcification showed similar, nonsignificant associations.

CONCLUSIONS

Despite its frequently demonstrated beneficial effects on coronary artery disease risk, alcohol consumption in this study was not associated with calcified atherosclerotic plaque in the coronary arteries or in the aorta. This suggests that its effects on cardiovascular risk may occur through mechanisms other than those associated with the development of calcified plaque.

The Significant Increase in Cardiovascular Disease Risk inAPOEɛ4 Carriers is Evident Only in Men Who Smoke: Potential Relationship Between Reduced Antioxidant Status and ApoE4

Data from 1668 men (316 cardiovascular disease events) from the Framingham Offspring Study was reanalysed, specifically examining APOE:smoking interactions. Overall hazard ratio (HR) for smoking was 1.95 (1.52, 2.50) compared to non-smokers. Using epsilon3/3 as a referent group, in non-smokers HRs for epsilon2 carriers (epsilon2+; 1.04 (0.61, 1.76) and epsilon4 carriers (epsilon4+; 1.04 (0.70, 1.54) showed no major risk increase. In smokers, HRs were 1.96 (1.26, 2.78) in epsilon3epsilon3 men, 3.46 (2.14, 5.60; p = 0.09 for interaction) in epsilon2+ and 3.81 (2.49, 5.84; p = 0.01 for interaction), with a significant interaction between daily cigarette consumption and APOE genotype on risk (p = 0.03). The potential mechanism for this APOEepsilon4:smoking interaction was examined in a second study of 728 Caucasian patients with diabetes, where markers of reactive oxygen species were available. APOE genotype was not associated with plasma OX-LDL or total antioxidant status (TAOS) in non-smokers. However, in smokers epsilon4+ had 26.7% higher plasma OX-LDL than other genotypes (APOE:smoking interaction p = 0.04), while epsilon2+ had 28.4% higher plasma TAOS than epsilon3epsilon3 and epsilon4+ combined (APOE:smoking interaction p = 0.026). Although direct extrapolation needs to be considered with caution, these results identify that the cardiovascular disease risk-raising effect of epsilon4+ is confined to smokers, and a feasible mechanism is presented by the reduced antioxidant capacity/increased OX-LDL of apoE4.