Association of genetic variation in apolipoprotein E and low density lipoprotein receptor with ischemic stroke in Northern Han Chinese

The association between polymorphism of LDL-R gene and ischemic stroke risk in Chinese population: A meta-analysis

Objective

Low-density lipoprotein receptor (LDL-R) gene polymorphisms have been indicated to be correlated with ischemic cerebrovascular disease including ischemic stroke susceptibility. However, the results from each published study are inconsistent.

Methods

All eligible case-control studies that met the search terms were retrieved in PubMed, Embase, Wanfang Med Online and Chinese National Knowledge Infrastructure (CNKI) databases. We identified seven independent case-control studies with a total of 10,355 subjects from Chinese population up to May 2023. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the susceptibility of ischemic stroke.

Results

Meta-analysis results indicated that rs1122608 polymorphism of LDL-R gene significantly decreased ischemic stroke risk under dominant model (OR = 0.69, 95% CI = 0.54-0.87), heterozygote comparison (OR = 0.69, 95% CI = 0.53-0.92) and allele comparison (OR = 0.74, 95% CI = 0.65-0.84) in overall analysis. Furthermore, pooled analysis showed that significant associations were observed between rs688 polymorphism and ischemic stroke risk in heterozygote carriers (OR = 1.71, 95% CI = 1.07-2.71) and dominant model (OR = 1.67, 95% CI = 1.04-2.68) in Chinese population.

Conclusions

Our comprehensive meta-analysis on the role of LDL-R gene rs1122608 and rs688 polymorphisms in the risk of ischemic stroke revealed that the rs1122608 polymorphism was associated with a decreased risk, while the rs688 polymorphism was associated with an increased risk of ischemic stroke in Chinese population. Further multicenter studies were needed to confirm the effect on the susceptibility of ischemic stroke.

Apolipoprotein E ε4 Polymorphism as a Risk Factor for Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction

Rising studies indicate that the apolipoprotein E (APOE) gene is related to the susceptibility of ischemic stroke (IS). However, certain consensus is limited by the lack of a large sample size of researches. This meta-analysis was performed to explore the potential association between the APOE gene and IS.

Methods

To identify relevant case control studies in English publications by October 2020, we searched PubMed, Embase, Web of Science, and the Cochrane Library. Pooled odds ratios (ORs) with fixed- or random-effect models and corresponding 95% confidence intervals (CIs) were calculated to analyze potential associations.

Results

A total of 55 researches from 32 countries containing 12207 IS cases and 27742 controls were included. The association between APOE gene ε4 mutation and IS was confirmed (ε4 vs. ε3 allele: pooled OR = 1.374, 95% CI, 1.214-1.556; ε2/ε4 vs. ε3/ε3: pooled OR = 1.233, 95% CI, 1.056-1.440; ε3/ε4 vs. ε3/ε3: pooled OR = 1.340, 95% CI, 1.165-1.542; ε4/ε4 vs. ε3/ε3: pooled OR = 1.833, 95% CI, 1.542-2.179; and APOE ε4 carriers vs. non-ε4 carriers: pooled OR = 1.377; 95% CI, 1.203-1.576). Interestingly, APOE ε4 mutation showed a dose-response correlation with IS risk (ε4/ε4 vs. ε2/ε4: pooled OR = 1.625; 95% CI, 1.281-2.060; ε4/ε4 vs. ε3/ε4: pooled OR = 1.301; 95% CI, 1.077-1.571). Similar conclusions were drawn in the small artery disease (SAD) subtype, but not in large artery atherosclerosis (LAA) or in cardioaortic embolism (CE), by subgroup analysis.

Conclusions

These observations reveal that specific APOE ε4 mutation was significantly associated with the risk of IS in a dose-dependent manner, while APOE ε4 mutation was related to SAD subtype onset without a cumulative effect.

Association Between the Apolipoprotein E Gene Polymorphism and Atherosclerotic Middle Cerebral Artery Stenosis

OBJECTIVES

Stenosis of the intracranial large arteries, especially the middle cerebral artery (MCA), is common in the Chinese population. We conducted a case-control study to investigate clinical and apolipoprotein E (ApoE) gene polymorphism of MCA atherosclerosis in the Chinese population.

MATERIALS AND METHODS

Polymerase chain reaction-based protocols were used to identify the genotypes of polymorphisms in ApoE genes. Clinical parameters and the genotypes of polymorphisms in the ApoE genes were compared in patients with and without MCA stenosis. The ApoE exon ε4 genotypes with risk factors were compared in the patients with and without MCA stenosis.

RESULTS

In total, 337 ischemic stroke patients were recruited, 156 cases with and 181 without MCA stenosis. Univariate analysis showed that the levels of systolic blood pressure and pulse pressure were higher in the MCA-stenosis group. There were no significant differences in the genotype and allele frequencies of the ApoE polymorphism observed between patients with and without MCA stenosis. However, there was a trend that the MCA-stenosis group tended to have more of genotype ε4/ε4 (3.8% vs. 0.6%, P=0.052) than the non-MCA-stenosis group. There was no effect of ApoE genotype and genotype-by-environment interactions on ischemic stroke susceptibility.

CONCLUSIONS

This present study indicated that the hypertension (ie, systolic blood pressure and pulse pressure) and the ApoEε4/ε4 genotype may be associated with the occurrence of MCA stenosis in the ischemic stroke Chinese patients.

Association between ApoE polymorphism and hypertension: A meta-analysis of 28 studies including 5898 cases and 7518 controls

Hypertension is one of the most common chronic diseases, constituting an independent risk factor for many diseases. Our study aimed to evaluate the association between apolipoprotein E (ApoE) genetic polymorphism and hypertension, and to provide evidence for the etiology of hypertension. Case-control studies of ApoE polymorphism and hypertension, which were included in PubMed, Embase, Web of Science, Medline, WanFang, Vip, and CNKI information databases, were selected and evaluated according to criteria of inclusion and exclusion. Eligible data were extracted and pooled, and were analyzed and assessed using Stata 12.0. Random-effect models were used when heterogeneity existed in between-study, and fixed-effect models were applied otherwise. A total of 28 studies that consisted of 5898 cases with hypertension and 7518 controls were selected. Alleles and genotypes of ApoE between cases and controls were compared. For ApoE alleles, we observed the contrast of ApoE ε2 versus ε3 allele yielded a pooled OR of 0.99 (95% CI: 0.87-1.11; P = 0.823), whereas the contrast of ε4 versus ε3 allele yielded a pooled OR of 1.95 (95% CI: 1.50-2.54; P < 0.001). For ApoE genotypes, compared with ε3/ε3 genotype, genotypes (ε2/ε2 and ε2/ε3) showed a possible association with hypertension (OR = 0.88; 95% CI: 0.79-0.99; P = 0.033), and genotypes (ε3/ε4 and ε4/ε4) had a 2.08-fold risk of developing hypertension (OR = 2.08; 95% CI: 1.58-2.74; P < 0.001). There is the association between ApoE polymorphism and hypertension: the genotypes carrying ε2 allele may be a protective factor, and the ApoE ε4 allele and the genotypes carrying ε4 allele may be risk factors for hypertension.

LDLR C1725T Gene Polymorphism Frequency in Type 2 Diabetes Mellitus Patients With Dyslipidemia

BACKGROUND

Dyslipidemia has a substantial role in the development of cardiovascular diseases in patients with type 2 diabetes mellitus (T2DM). Determining the genetic profile of T2DM patients with dyslipidemia is important in order to reduce the risk of microvascular and macrovascular complications. Low-density lipoprotein receptor (LDLR) plays a critical role in plasma lipoprotein hemostasis. LDLR mutations/polymorphisms cause changes at the lipoprotein level. The objective of this study is to determine the frequency of LDLR (rs179989) polymorphisms in Turkish T2DM patients with dyslipidemia.

METHODS

The study group consisted of 217 T2DM patients with dyslipidemia including 28 cases with myocardial infarction and 212 healthy controls. Genomic DNA was isolated from venous blood samples and genotype analysis was carried out on the LightCycler^® 480 instrument. The χ² test was used to compare genotype distributions.

RESULTS

There were no significant differences in the frequency or allelic distribution of the LDLR C1725T (rs1799898) genotype between the type 2 diabetic dyslipidemia patients and the control group (P > 0.05).

CONCLUSION

LDLR C1725T polymorphism was not associated with lipid parameters, and dyslipidemia in T2DM patients.

Association between Apolipoprotein ε4 Gene Polymorphism and Risk of Ischemic Stroke: A Meta-Analysis

BACKGROUND

Previous studies examining the association of apolipoprotein E (APOE) gene polymorphism with the risk of ischemic stroke (IS) have yielded conflicting results. Therefore, we performed a meta-analysis to investigate the association between APOE ε4 gene polymorphism and risk of IS.

SUMMARY

A literature search for genetic association studies published before May 30, 2015, was conducted in the PubMed, EMBASE and Google Scholar databases. The following search terms were used: (apolipoprotein E) or (APOE) and (ε4) and (polymorphism) or (polymorphisms) and ('ischemic stroke' or 'IS') and ('cerebral infarction' or 'CI') and ('genetic polymorphism' or 'single nucleotide polymorphisms' or 'SNP'). ORs and 95% CIs were used to calculate the strength of association. Begg's funnel plot was used to assess the potential for publication bias. In our meta-analysis, 26 case-control studies involving 6,397 IS cases and 19,053 controls were included. Overall significant association between carrier of ε4 allele and risk of IS was observed (OR 1.43, 95% CI 1.10-1.85, p = 0.007). In the subgroup analysis based on ethnicity, a significant association between Apo ε4 carrier and risk of IS was observed in Asian studies (OR 1.53, 95% CI 1.04-2.25, p = 0.031) whereas borderline significant association between APO ε4 carrier and risk of IS was observed in Caucasian studies (OR 1.36, 95% CI 0.95-1.93, p = 0.093).

KEY MESSAGES

Our meta-analysis suggests that APOE ε4 allele is associated with higher risk of IS in Asian population as compared to Caucasian population.

Association of APOE (E2, E3 and E4) gene variants and lipid levels in ischemic stroke, its subtypes and hemorrhagic stroke in a South Indian population

In the present study we evaluated the association of APOE (E2/E3/E4) polymorphism with ischemic stroke (n=620), its subtypes and hemorrhagic stroke (n=250) in a South Indian population from Telangana. The genotypes were determined using PCR-RFLP while lipid levels were measured using commercially available kits. We found significant difference in the genotypic distribution between hemorrhagic stroke patients and controls for certain genetic models [E2/E2 vs. E2/E4; E3/E3 vs. E2/E3; E3/E3 vs. E2/E4; E4/E4 vs. E2/E3; E4/E4 vs.E2/E4 and E3 vs. E4]. However, no significant difference was observed in genotypic distribution between ischemic stroke patients and controls. On analysing the genotypic distribution between ischemic and hemorrhagic stroke patients, statistically significant difference was observed in specific genetic models [E2/E2 vs. E2/E4; E3/E3 vs. E2/E3; E3/E3 vs. E2/E4; E4/E4 vs. E2/E3 and E4/E4 vs. E2/E4]. In ischemic stroke subtypes analysing for alleles E3 vs. E2 and E3 vs. E4, we found significant association with intracranial large artery (p=0.01), cardioembolic stroke (p=0.001 and p=0.0004) and lacunar stroke (p=0.02). Analysing the association of various genotypes with different lipid levels significant association was observed for VLDL (P=0.000) and for triglyceride (P=0.000) levels with E2/E4 and E3/E4 genotypes in ischemic stroke but not in hemorrhagic stroke. In conclusion, our results suggest that APOE polymorphism does seem to play a role in hemorrhagic stroke and also in the development of specific subtypes of ischemic stroke. Further, in ischemic stroke VLDL and triglycerides levels were found to be significantly associated with E2/E4 and E3/E4 genotypes.

Apolipoprotein E genotyping and questionnaire-based assessment of lifestyle risk factors in dyslipidemic patients with a family history of Alzheimer's disease: test development for clinical application

The cholesterol-raising properties of the apolipoprotein E (APOE) epsilon-4 (ε-4) allele has been validated in the South African population. Mounting evidence supports the added value of APOE genotyping for the evaluation of cardiovascular risk in dyslipidemic patients beyond its established role in the diagnosis of late-onset Alzheimer's disease (AD). The aim of this study was to determine the potential benefits of combining AD family history with questionnaire-based lifestyle assessment to facilitate the clinical interpretation of APOE genotyping results. A total of 580 unrelated South African individuals prospectively enrolled in a chronic disease screening program incorporating a genetic component (2010-2015) was selected for inclusion in this study based on the presence (75) or absence (505) of AD family history. Biochemical assessment of their lipid profiles was performed according to standard laboratory protocols. All study participants were genotyped for the APOE ε-2/ε-3/ε-4 alleles using allele-specific TaqMan real-time polymerase chain reaction technology. In patients without a family history of AD, APOE genotype modified the relationship between alcohol intake and body mass index (p = 0.026), with a significant positive correlation noted between these parameters being limited to ε-4 allele carriers. APOE genotype also modified the association between alcohol intake and total serum cholesterol in patients with a positive family history of AD (p = 0.026). We demonstrated the benefits of a questionnaire-based approach for assessment of lifestyle risk factors to facilitate clinical interpretation of APOE genotyping results for targeted intervention in a genetic subgroup of dyslipidemic patients at increased risk for AD.

Relationships of LDLR genetic polymorphisms with cerebral infarction: a meta-analysis

This meta-analysis was undertaken to identify the relationships between genetic polymorphisms in the LDLR gene and the risk of cerebral infarction. The Web of Science (1945-2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966-2013), EMBASE (1980-2013), CINAHL (1982-2013) and the Chinese Biomedical Database (CBM) (1982-2013) were searched for relevant articles without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. Crude odds ratios (OR) with their corresponding 95% confidence interval (CI) were calculated. Eight case-control studies with a total of 4,655 patients with cerebral infarction and 15,920 healthy control subjects were included in our meta-analysis. Five common polymorphisms in the LDLR gene were evaluated, including rs11669576 A > T, rs1433099 C > T, rs5925 C > T, rs688 C > T, rs1122608 T > G in the LDLR gene. The results of this meta-analysis revealed that cerebral infarction patients had a higher frequency of LDLR genetic polymorphisms than that of healthy controls (allele model: OR 1.17, 95% CI 1.05-1.30, P = 0.004; dominant model: OR 1.18, 95% CI 1.05-1.33, P = 0.007; homozygous model: OR 1.50, 95% CI 1.03-2.16, P = 0.032; respectively), especially for the rs11669576 A > T, rs1433099 C > T and rs5925 C > T polymorphisms. Among different ethnic subgroups, the results demonstrated positive correlations between LDLR genetic polymorphisms and an increased risk of cerebral infarction among both Asians and Caucasians under the allele and dominant models (all P < 0.05). Our findings indicate that LDLR genetic polymorphisms may be strongly involved in the pathogenesis of cerebral infarction, especially the rs11669576 A > T, rs1433099 C > T, rs5925 C > T polymorphisms.

Genetic risk factors for perinatal arterial ischemic stroke

The cause of perinatal arterial ischemic stroke is unknown in most cases. We explored whether genetic polymorphisms modify the risk of perinatal arterial ischemic stroke. In a population-based case-control study of 1997-2002 births at Kaiser Permanente Northern California, we identified 13 white infants with perinatal arterial ischemic stroke. Control subjects included 86 randomly selected white infants. We genotyped polymorphisms in nine genes involved in inflammation, thrombosis, or lipid metabolism previously linked with stroke, and compared genotype frequencies in case and control individuals. We tested several polymorphisms: tumor necrosis factor-α -308, interleukin-6, lymphotoxin A, factor V Leiden, methyltetrahydrofolate reductase 1298 and 667, prothrombin 20210, and apolipoprotein E ε2 and ε4 alleles. Patients with perinatal arterial ischemic stroke were more likely than control subjects to demonstrate at least one apolipoprotein E ε4 allele (54% vs 25%, P = 0.03). More patients with perinatal arterial ischemic stroke carried two ε4 alleles than did control subjects (15% vs 2%, P = 0.09), although this finding lacked statistical significance. Proinflammatory and prothrombotic polymorphisms were not associated with perinatal arterial ischemic stroke. The apolipoprotein E polymorphism may confer genetic susceptibility for perinatal arterial ischemic stroke. Larger population-based studies are required to confirm this finding.

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.

Hypoxia-induced mobilization of stored triglycerides in the euryoxic goby Gillichthys mirabilis

Environmental hypoxia is a common challenge that many aquatic organisms experience in their habitat. Responding to hypoxia requires metabolic reprogramming so that energy-demanding processes are regulated to match available energy reserves. In this study we explored the transcriptional control of metabolic reorganization in the liver of a hypoxia-tolerant burrow-dwelling goby, Gillichthys mirabilis. Gene expression data revealed that pathways associated with triglyceride hydrolysis were upregulated by hypoxia whereas pathways associated with triglyceride synthesis were downregulated. This finding was supported by tissue histology, which showed that the size of hepatic lipid droplets declined visibly during exposure to hypoxia. Proton nuclear magnetic resonance analysis confirmed the mobilization of hepatic triglycerides, which declined 2.7-fold after 5 days of hypoxia. The enzyme, adipose triglyceride lipase, was implicated in the mobilization of triglycerides because its expression increased at the level of both transcript and protein. This observation raises questions regarding the regulation of fat metabolism during hypoxia and the role played by the hypoxia-responsive gene leptin.

A tagging SNP in ALOX5AP and risk of stroke: a haplotype-based analysis among eastern Chinese Han population

A genome-wide approach found significant association of two at-risk haplotypes (HapA, HapB) in the ALOX5AP gene with myocardial infarction and stroke. To date, it is still controversial whether ALOX5AP gene polymorphisms are risk factors for stroke. The aim of the present study is to investigate the association between the ALOX5AP gene polymorphism and the risk for stroke in Eastern Chinese Han population with a haplotype-based analysis. We conducted a comprehensive association study of 507 stroke patients and 510 healthy controls to assess the association between the ALOX5AP tagging single-nucleotide polymorphisms (tSNPs) and stroke risk. Genotyping was performed using the PCR-RFLP assay. In the single-locus analysis, we found that the rs9579646 AG genotype was associated with a marginally decreased risk for stroke (adjusted odds ratio, 0.65; 95% confidence interval, 0.45-0.96), compared with the AA genotype. Haplotype-based association analysis of block 2 involving rs10507391 and rs12429692 revealed that the decreased risk of stroke was significantly associated with haplotype AA (OR, 0.66; 95% CI, 0.46-0.95). These results suggested that the genetic variants in ALOX5AP might modulate the risk of stroke in Eastern Chinese Han population. The frequencies of single-marker alleles and haplotypes showed remarkable differences from those in other populations.

[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.

Apolipoprotein E Genotype and Cardiovascular Diseases in the Elderly

The apolipoprotein E (APOE) genotype is a genetic risk factor for dementia, Alzheimer’s disease, and cardiovascular disease (CVD). It includes three alleles (e2, e3, e4) that are located on chromosome 19q3.2. The e3 allele is the most common and is more common in people of Northern European ancestry and less common in those of Asian ancestry. Those with at least one e4 allele are at increased risk for CVD outcomes. It is well established that the presence of an e4 allele is linked to higher low-density lipoprotein cholesterol levels, even at young ages. Even though most CVD occurs in older people, there are few studies of the effects of APOE on CVD in older people. This review addresses recent research on the links between APOE, CVD, and vascular mechanisms by which APOE may affect CVD in the elderly.

Genetic variations in regulatory pathways of fatty acid and glucose metabolism are associated with obesity phenotypes: a population-based cohort study

BACKGROUND

As nuclear receptors and transcription factors have an important regulatory function in adipocyte differentiation and fat storage, genetic variation in these key regulators and downstream pathways may be involved in the onset of obesity.

OBJECTIVE

To explore associations between single nucleotide polymorphisms (SNPs) in candidate genes from regulatory pathways that control fatty acid and glucose metabolism, and repeated measurements of body mass index (BMI) and waist circumference in a large Dutch study population.

METHODS

Data of 327 SNPs across 239 genes were analyzed for 3575 participants of the Doetinchem cohort, who were examined three times during 11 years, using the Illumina Golden Gate assay. Adjusted random coefficient models were used to analyze the relationship between SNPS and obesity phenotypes. False discovery rate q-values were calculated to account for multiple testing. Significance of the associations was defined as a q-value < or = 0.20.

RESULTS

Two SNPs (in NR1H4 and SMARCA2 in women only) were significantly associated with both BMI and waist circumference. In addition, two SNPs (in SIRT1 and SCAP in women only) were associated with BMI alone. A functional SNP, in IL6, was strongly associated with waist.

CONCLUSION

In this explorative study among participants of a large population-based cohort, five SNPs, mainly located in transcription mediator genes, were strongly associated with obesity phenotypes. The results from whole genome and candidate gene studies support the potential role of NR1H4, SIRT1, SMARCA2 and IL6 in obesity. Although replication of our findings and further research on the functionality of these SNPs and underlying mechanism is necessary, our data indirectly suggest a role of GATA transcription factors in weight control.