Associations of apolipoprotein E exon 4 and lipoprotein lipase S447X polymorphisms with acute ischemic stroke and myocardial infarction

Meta-analysis of the association between Apolipoprotein E polymorphism and risks of myocardial infarction

Background

Myocardial infarction (MI) remains the leading cause of death and disability among cardiovascular diseases worldwide. Studies show that elevated low-density lipid protein cholesterol (LDL-C) levels confer the highest absolute risk of MI, and Apolipoprotein E (ApoE) is implicated in regulating levels of triglycerides (TGs), cholesterol, and LDL-C. Our study aimed to evaluate the association between APOE polymorphism and MI, and to provide evidence for the etiology of MI.

Methods

Case–control studies on the association between APOE polymorphisms and the risk of myocardial infarction were included by searching PubMed, Web of Science, and CNKI, and this meta-analysis was written in accordance with PRISMA guideline statement. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using either random-effects or fixed-effects models by R software.

Results

A total of 33 eligible articles involving 13,706 cases and 14,817 controls were finally selected. The pooled analysis based on the total eligible articles showed that the risk of MI was associated with ApoE epsilon 2 and epsilon 4 alleles. The results showed that patients with MI had a low frequency of the ε2 allele (OR 0.74, 95% CI 0.64–0.86) and a high frequency of the ε4 allele (OR 1.24, 95% CI 1.09–1.42).

Conclusions

APOE ε2-involved genotypes may be protective factors for MI; in contrast, ε4-involved genotypes (ε4/ε3 vs. ε3/ε3, and ε4/ε4 vs. ε3/ε3) may be risk factors for MI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02566-0.

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.

Lipoprotein Lipase Gene Polymorphisms Are Associated with Myocardial Infarction Risk: A Meta-Analysis

Aims: Many studies and researchers have reported on the genetic association between lipoprotein lipase (LPL) gene polymorphisms and myocardial infarction (MI). The results, however, have been inconclusive. Therefore, we assessed the relationship of LPL gene polymorphisms and MI risk by performing a meta-analysis. Methods: Literature was retrieved through PubMed, Web of Science, the Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), and Embase databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the genetic associations between LPL gene polymorphisms and MI risk. A total of nine studies, with 10 individual groups, comprising 2785 cases and 4317 controls were used for this meta-analysis. Results: The allelic (p = 0.0003, OR [95% CI] = 0.86 [0.79-0.93]) and dominant models (p = 0.001, OR [95% CI] = 0.83 [0.73-0.93]), but not the recessive model (p > 0.05) of LPL gene showed that the HindIII variant significantly decreased the risk of MI. In addition, the allelic model (p = 0.04, OR [95% CI] = 0.71 [0.50-0.99]) for the S447X variant showed a significant decrease in the risk of MI. No association was observed between the PvuII variant and MI (p > 0.05). A subgroup analysis based on ethnicity revealed that all of the genetic models (allelic model: p < 0.00001, OR [95% CI] = 0.62 [0.51-0.77]; dominant model: p = 0.003, OR [95% CI] = 0.66 [0.50-0.87]; recessive model (p = 0.02, OR [95% CI] = 0.47 [0.25-0.88]) found an association of the HindIII polymorphism with MI in the Asian, but not in the Caucasian population (p > 0.05). Under the dominant model the HindIII SNP was also shown to be associated with MI risk in the Caucasian population (p = 0.03, OR [95% CI] = 0.87 [0.76-0.99]). In addition, the allelic (p = 0.02, OR [95% CI] = 0.75 [0.59-0.95]) and dominant models (p = 0.02, OR [95% CI] = 0.51 [0.29-0.90]) for S447X demonstrated a significantly decreased MI risk in the Caucasian, but not in the Asian population (p > 0.05). Conclusions: LPL HindIII and S447X polymorphisms, but not PvuII might be the protective factors for MI. To confirm these results, case-control studies with larger numbers of subjects need to be conducted.

Screening and identification of potential protein biomarkers for the early diagnosis of acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the most serious type of heart disease. Clinically, there is an urgent need to discover diagnostic biomarkers for the early diagnosis of AMI.

Methods

Serum proteomic profiles in AMI patients, healthy controls, and stable angina pectoris (SAP) patients were explored and compared by iTRAQ-2DLC-MS/MS. The clinical data of AMI patients were also analyzed. Differentially expressed proteins were validated by enzyme linked immunosorbent assay (ELISA), and diagnostic models were constructed.

Results

A total of 39 differentially expressed proteins were identified in AMI patients. The results showed that the serum levels of apolipoprotein E (APOE) in AMI patients were notably higher than those in the healthy controls (P=0.0172). The serum levels of aspartate aminotransferase (AATC) in AMI patients were markedly higher than those in the healthy controls and SAP patients (P<0.0001 and P<0.0001, respectively). The serum levels of fibronectin (FINC) in SAP patients were significantly higher than those in the healthy controls and AMI patients (P=0.0043 and P=0.0044, respectively). Clinical data analysis showed a considerable difference in blood glucose levels, troponin I (TNI), and creatine kinase (CK) in AMI patients compared with SAP patients and healthy controls. A diagnostic model consisting of AATC and clinical indicators [lactate dehydrogenase (LDH) and CK] was established to distinguish between AMI patients and healthy controls, with an area under the curve (AUC) value of 0.993 sensitivity and specificity of 96.2% and 96.3%, respectively. A diagnostic model consisting of AATC and CK was established to distinguish between AMI patients and SAP patients, with an AUC value of 0.975 and a sensitivity and specificity of 85.2% and 79.30%, respectively.

Conclusions

In this study, differentially expressed proteins in AMI patients were combined with clinical indexes, LDH and CK, and two diagnostic models were constructed. This study may provide meaningful data for the early diagnosis of AMI.

The HindIII and PvuII polymorphisms of lipoprotein lipase (LPL) gene reduce the risk of ischemic stroke (IS): A meta-analysis

BACKGROUND

Lipoprotein lipase (LPL) polymorphisms were suggested to be the risk factor for ischemic stroke (IS). However, controversial results were obtained. Our objective was to investigate the association of LPL polymorphisms at Ser447Ter, HindIII (+/-), and PvuII (+/-) with IS risk.

METHODS

Literatures search were carried out on databases: PubMed, Web of science, the Cochrane database of system reviews, Chinese National Knowledge Infrastructure, and Embase. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to detect the relationship between LPL polymorphisms and the risk of IS.

RESULTS

No significant association was detected between LPL Ser447Ter and IS in allelic, dominant, or recessive models (P > .05). Significant lower frequencies of allelic and dominant models of LPL HindIII (+/-) and PvuII (+/-) in cases were detected (HindIII (+/-): allelic model: P = .0002, OR[95%CI] = 0.80 [0.71, 0.90]; dominant model: P = 0.003, OR[95%CI] = 0.80 [0.69, 0.92]; PvuII (+/-): allelic model: P < 0.0001, OR[95%CI] = 0.75[0.65-0.86]; dominant model: P = 0.02, OR[95%CI] = 0.67[0.48-0.93]). And the recessive model of PvuII (+/-) was significantly associated with the IS risk (P = .01, OR[95%CI] = .71[0.55-0.93]). Subgroup analysis stratified by ethnicity showed that the frequencies of allelic, dominant, and recessive models of HindIII (+/-), as well as dominant model of PvuII (+/-) were significant lower in Asian cases (HindIII (+/-): allelic model: P < .00001, OR[95%CI] = 0.69 [0.59, 0.79]; dominant model: P < .0001, OR[95%CI] = 0.69 [0.58, 0.83]; recessive model: P = .005, OR[95%CI] = 0.66 [0.50, 0.89]; PvuII (+/-): dominant model: P = .0008, OR[95%CI] = 0.66 [0.51-0.84]), but not in Caucasian cases (P > .05). In addition, the frequencies of allelic and recessive models of PvuII (+/-) significantly decreased in Caucasian cases (P < .05).

CONCLUSION

the HindIII (+/-) and PvuII (+/-), but not the Ser447Ter might be the protective factors for IS.

Associations between LPL gene polymorphisms and coronary artery disease: evidence based on an updated and cumulative meta-analysis

Lipoprotein lipase (LPL) is widely linked to lipid and lipoprotein metabolism, but its effects on coronary artery disease (CAD) are not clearly elucidated. The aim of this study was to clarify the association between LPL gene polymorphisms and CAD susceptibility. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to estimate the strength of the relationship between LPL gene polymorphisms and CAD risk. Comprehensive electronic databases, including PubMed, EMBASE, Web of Science, and the Cochrane Library, were systematically searched. A total of 45 records containing 80 eligible studies were analyzed. The results indicated an increased risk between the LPL D9N polymorphism and susceptibility to CAD in the dominant genetic model (AA + GA vs. GG: OR = 1.46, 95% CI = 1.14-1.87), whereas the LPL HindIII polymorphism showed a protective effect against CAD under all tested models (GG+GT vs. TT: OR = 0.85, 95% CI = 0.75-0.97; GG vs. TT + TG: OR = 0.62, 95% CI = 0.47-0.83; G vs. T: OR = 0.81, 95% CI = 0.71-0.92). No significant association was identified for the LPL N291S and PvuII polymorphisms. Stratification analysis by ethnicity suggested a significant correlation between the LPL S447X polymorphism and CAD susceptibility in Caucasians under the dominant and allele genetic models. In summary, our meta-analysis indicated that the LPL D9N polymorphism was associated with an increased risk of CAD, whereas the S447X and HindIII polymorphisms showed protective effects. There was no association observed between the N291S and PvuII polymorphisms and CAD risk.

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

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

Meta-analysis of apolipoprotein E gene polymorphism and susceptibility of myocardial infarction

A number of case-control studies have been conducted to clarify the association between ApoE polymorphisms and myocardial infarction (MI); however, the results are inconsistent. This meta-analysis was performed to clarify this issue using all the available evidence. Searching in PubMed retrieved all eligible articles. A total of 33 studies were included in this meta-analysis, including 18752 MI cases and 18963 controls. The pooled analysis based on all included studies showed that the MI patients had a decreased frequency of the ε2 allele (OR = 0.78, 95% CI = 0.70–0.87) and an increased frequency of the ε4 allele (OR = 1.15, 95% CI = 1.10–1.20); The results also showed a decreased susceptibility of MI in the ε2ε3 vs. ε3ε3 analysis (OR = 0.79, 95% CI = 0.68–0.90) and in the ε2 vs. ε3 analysis (OR = 0.78, 95% CI = 0.69–0.89), an increased susceptibility of MI in the ε3ε4 vs. ε3ε3 analysis (OR = 1.26, 95% CI = 1.12–1.41), in the ε4 vs. ε3 analysis (OR = 1.22, 95% CI = 1.12–1.32) and in the ε4ε4 vs. ε3ε3 analysis (OR = 1.59, 95% CI = 1.15–2.19). However, there were no significant associations among polymorphisms and MI for the following genetic models: frequency of the ε3 allele (OR = 0.99, 95% CI = 0.96–1.02); ε2ε2 vs. ε3ε3 analysis (OR = 0.73, 95% CI = 0.40–1.32); or ε2ε4 vs. ε3ε3 analysis (OR = 1.10, 95% CI = 0.99–1.21). Our results suggested that the ε4 allele of ApoE is a risk factor for the development of MI and the ε2 allele of ApoE is a protective factor in the development of MI.

The genetics of vascular incidents associated with second-generation antipsychotic administration

Second-generation antipsychotics (SGA) have been associated with risk of stroke in elderly patients, but the molecular and genetic background under this association has been poorly investigated. The aim of the present study was to prioritize a list of genes with an SGA altered expression in order to characterize the genetic background of the SGA-associated stroke risk. Genes with evidence of an altered expression after SGA treatments in genome-wide investigations, both in animals and men, were identified. The Genetic Association Database (GAD) served to verify which of these genes had a proven positive association with an increased stroke risk, and along with it each evidence was tested and recorded. Seven hundred and forty five genes had evidence of a change of their expression profile after SGA administration in various studies. Nine out of them have also been significantly related to an increased strokes risk. We identified and described nine genes as potential candidates for future genetic studies aimed at identifying the genetic background of the SGA-related stroke risk. Further, we identify the molecular pathways in which these genes operate in order to provide a molecular framework to understand on which basis SGA may enhance the risk for stroke.

Association between the apolipoprotein E gene polymorphism and ischemic stroke in Chinese populations: New data and meta-analysis

Ischemic stroke (IS) is a complex multifactorial inherited disease. Many studies have focused on the potential genetic effects of apolipoprotein E (ApoE) gene polymorphism on IS. However, inconsistencies still exist in the association of ApoE gene polymorphism with IS. The aim of this study was to investigate the ApoE gene polymorphism in relation to IS in the Guangxi Han populations and assess the risk of various ApoE genotypes associated with IS in Chinese populations. We conducted a case-control study involving a total of 166 IS cases and 192 healthy controls to investigate the association of ApoE gene polymorphism with IS in the Guangxi Han populations. Furthermore, we performed a meta-analysis to investigate whether the ApoE gene polymorphism is associated with IS in Chinese populations. There was no evidence for a significant association between ApoE gene polymorphism and IS in the Guangxi Han populations (ɛ2/ɛ2 vs. ɛ3/ɛ3: OR=1.25, 95% CI=0.08–20.17; ɛ2/ɛ3 vs. ɛ3/ɛ3: OR=1.49, 95% CI=0.79–2.79; ɛ2/ɛ4 vs. ɛ3/ɛ3: OR=1.25, 95% CI=0.17–9.00; ɛ3/ɛ4 vs. ɛ3/ɛ3: OR=1.10, 95% CI=0.60–2.04; ɛ4/ɛ4 vs. ɛ3/ɛ3: OR=2.50, 95% CI=0.22–27.87; allele ɛ2 vs. allele ɛ3: OR=1.39, 95% CI=0.80–2.44; allele ɛ4 vs. allele ɛ3: OR=1.16, 95% CI=0.68–1.98). In our meta-analysis, a significant association of ApoE gene polymorphism with IS was found in the genetic model of ɛ2/ɛ4 vs. ɛ3/ɛ3 (OR=2.04, 95% CI=1.45–2.85), ɛ3/ɛ4 vs. ɛ3/ɛ3 (OR=1.93, 95% CI=1.42–2.62), ɛ4/ɛ4 vs. ɛ3/ɛ3 (OR=3.41, 95% CI=2.17–5.34) and allele ɛ4 vs. allele ɛ3 (OR=2.34, 95% CI=1.91–2.86). However, no clear associations were found in the model of ɛ2/ɛ2 vs. ɛ3/ɛ3 (OR=1.56, 95% CI=0.90–2.71), ɛ2/ɛ3 vs. ɛ3/ɛ3 (OR=0.93, 95% CI=0.79–1.09) and allele ɛ2 vs. allele ɛ3 (OR=1.10, 95% CI=0.97–1.25). In conclusion, no association was found between ApoE gene polymorphism and IS in the Guangxi Han populations, while the results of the meta-analysis indicate that the ApoE mutation allele ɛ4 increases the risk of IS in Chinese populations.

Genome-wide association analysis of anti-TNF drug response in patients with rheumatoid arthritis

BACKGROUND

Treatment strategies blocking tumour necrosis factor (anti-TNF) have proven very successful in patients with rheumatoid arthritis (RA). However, a significant subset of patients does not respond for unknown reasons. Currently, there are no means of identifying these patients before treatment. This study was aimed at identifying genetic factors predicting anti-TNF treatment outcome in patients with RA using a genome-wide association approach.

METHODS

We conducted a multistage, genome-wide association study with a primary analysis of 2 557 253 single-nucleotide polymorphisms (SNPs) in 882 patients with RA receiving anti-TNF therapy included through the Dutch Rheumatoid Arthritis Monitoring (DREAM) registry and the database of Apotheekzorg. Linear regression analysis of changes in the Disease Activity Score in 28 joints after 14 weeks of treatment was performed using an additive model. Markers with p<10(-3) were selected for replication in 1821 patients from three independent cohorts. Pathway analysis including all SNPs with p<10(-3) was performed using Ingenuity.

RESULTS

772 markers showed evidence of association with treatment outcome in the initial stage. Eight genetic loci showed improved p value in the overall meta-analysis compared with the first stage, three of which (rs1568885, rs1813443 and rs4411591) showed directional consistency over all four cohorts studied. We were unable to replicate markers previously reported to be associated with anti-TNF outcome. Network analysis indicated strong involvement of biological processes underlying inflammatory response and cell morphology.

CONCLUSIONS

Using a multistage strategy, we have identified eight genetic loci associated with response to anti-TNF treatment. Further studies are required to validate these findings in additional patient collections.

Large-scale meta-analysis of genetic studies in ischemic stroke: Five genes involving 152,797 individuals

BACKGROUND:

Ischemic stroke descent has a genetic basis. Stroke represents a complex trait, which is assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies.

MATERIALS AND METHODS:

We performed a literature-based systematic review of genetic association studies in stroke abound several populations. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for each gene-disease association. Following a review of 300 manuscripts, five candidate gene variants were analyzed among 152,797 individuals (45,433 cases and 107,364 controls).

RESULTS:

For these five candidate genes studied, the prothrombin OR is 1,57 (1,23-2,89), the factor V Leiden OR is 1,43 (0,67-6,24), the mean OR of angiotensin I converting enzyme (ACE) insertion/deletion (I/D) polymorphism is 1,11 (1,02-1,25), the summary OR for the C677T variant of 5,10-methylenetetrahydrofolate reductase (MTHFR) is 1,23 (0,61-1,47) and the pooled OR for the apolipoprotein E (APOE) gene is 0,95 (0,77-1,14) .

CONCLUSION:

These data suggest the genetic associations of some genes with ischemic stroke and it is necessary to compete with other genes. Our findings could represent an epidemiological base and a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

Lipoprotein lipase Ser447Ter polymorphism associated with the risk of ischemic stroke: a meta-analysis

INTRODUCTION

Previous studies suggested lipoprotein lipase (LPL) Ser447Ter and Asn291Ser polymorphisms were associated with the risk of ischemic heart disease, however, their effects on ischemic stroke were controversial. A meta-analysis was performed to assess the associations between these two LPL polymorphisms and the risk of ischemic stroke.

METHODS

The electronic databases PubMed and Embase were used to identify relevant studies by two interviews independently. The pooled odds ratios (ORs) and weighted mean differences (WMD) with 95% confidence interval (CI) were estimated for the risk of ischemic stroke and the plasma lipids in various Ser447Ter genotypes respectively. A fixed or random effect model was selected for pooling data based on homogeneity test.

RESULTS

13 studies including 4,681 ischemic stroke cases and 8,516 controls were involved in this meta-analysis. Overall, LPL Ter447 variant was associated with a significantly reduced risk for ischemic stroke (OR=0.79, 95% CI: 0.68-0.93) both in Caucasian (OR=0.87, 95% CI: 0.77-0.97) and East-Asian (OR=0.65, 95% CI: 0.43-0.99), whereas no significant association of Ser291 variant was observed (OR=1.25, 95% CI: 0.96-1.63). The Ser447Ter polymorphism may be more important in association with the decreased risk of atherosclerotic stroke (OR=0.44, 95% CI: 0.32-0.62) which derived from significantly increased high density lipoprotein cholesterol, decreased triglyceride and total cholesterol in Ter447 carriers compared with non-carriers.

CONCLUSIONS

This meta-analysis indicated that LPL Ser447Ter polymorphism was associated with a significant reduction in the risk of ischemic stroke, especially atherosclerotic stroke subtype in both Caucasian and East-Asian.

Investigation of the Interaction Between the Ser447Term Polymorphism of Lipoprotein Lipase and the Stroke-Related Risk Factors in Ischemic Stroke

The present study aimed to investigate the interaction between the Ser447Term polymorphism in the lipoprotein lipase (LPL) gene and some common risk factors for stroke. A total of 704 unrelated patients with ischemic stroke were recruited for genetic analysis; they were all of Han Chinese origin. These patients were classified into subgroups based on their exposure to stroke-related risk factors, including type 2 diabetes, hypertension, smoking, and hyperlipidemia. The Ser447Term polymorphism was genotyped by PCR-based restriction fragment length polymorphism analysis. The chi-square (χ (2)) test showed that the frequency of Ser447Term G allele was significantly higher in stroke patients with a history of diabetes than in those without a history of diabetes (χ (2) = 7.25, P = 0.007, OR = 1.78, 95%CI 1.18-2.68). Allelic association was not observed in patients exposed to the other three stroke-related risk factors. The combined effect of the LPL gene polymorphisms and diabetes may contribute to the development of a subgroup of ischemic stroke.

Air pollution, obesity, genes and cellular adhesion molecules

OBJECTIVES

Particulate matter has been associated with acute cardiovascular outcomes, but our understanding of the mechanism is incomplete. We examined the association between particulate matter and cell adhesion molecules. We also investigated the modifying effect of genotype and phenotype variation to gain insight into the relevant biological pathways for this association.

METHODS

We used mixed regression models to examine the association of PM(2.5) (particulate matter < or = 2.5 microm in diameter) and black carbon with serum concentrations of soluble intercellular adhesion molecule (sICAM-1) and soluble vascular cell adhesion molecule (sVCAM-1), markers of endothelial function and inflammation, in a longitudinal study of 809 participants in the Normative Ageing Study (1819 total observations). We also examined whether this association was modified by genotype, obesity or diabetes status. Genes selected for analyses were either related to oxidative stress, endothelial function, lipid metabolism or metal processing.

RESULTS

Black carbon during the 2 days prior to blood draw was significantly associated with increased sVCAM-1 (4.5% increase per 1 microg/m(3), 95% CI 1.1 to 8.0). Neither pollutant was associated with sICAM-1. Larger effects of black carbon on sVCAM were seen in subjects with obesity (p=0.007) and who were GSTM1 null (p=0.02).

CONCLUSIONS

Black carbon is associated with markers of endothelial function and inflammation. Genes related to oxidative defence may modify this association.

Apolipoprotein E polymorphism and expression in type 2 diabetic patients with nephropathy: clinicopathological correlation

BACKGROUND

Diabetic nephropathy represents a heterogeneous group of renal pathologies that may be associated with genetic susceptibility. There have been clinical reports on the risk association of diabetic nephropathy with an apolipoprotein E (ApoE) exon 4 polymorphism although its correlations with renal histopathological changes have not been explored.

METHODS

A total of 213 adult autopsies with type 2 diabetes and 111 non-diabetic control cases were analysed. Genomic DNA samples were obtained from spleen tissues. The ApoE genotype was determined by PCR-LDR analysis. Histopathological examination of kidney sections was performed in a subset of 51 diabetic and 111 control cases. ApoE protein expression in diabetic carriers with similar clinical status was examined by immunohistochemical staining.

RESULTS

In type 2 diabetes, epsilon2 carriers (P = 0.04; odds ratio = 5.42; 95% CI: 1.10-26.8) and epsilon3/epsilon4 (P = 0.04; odds ratio = 22.5; 95% CI: 1.11-454.90) genotype carriers were more likely to have glomerular hypertrophy than were epsilon3/epsilon3 carriers. The epsilon2 carriers showed an increase in glomerular ApoE protein expression. A correlation between ApoE genotype and nodular glomerulosclerosis was not found.

CONCLUSIONS

Our findings confirm the risk association of the ApoE polymorphism with diabetic nephropathy in clinical studies and is the first study demonstrating the correlations between ApoE genotypes, protein expression and structural changes in diabetic nephropathy.

Genetic polymorphisms for the study of multifactorial stroke

Single-gene disorders explain only a minority of stroke cases. Stroke represents a complex trait, which is usually assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies, with controversial results. Therefore, it is difficult for the clinician to establish the validity and the level of clinical applicability of the previously reported associations between genetic factors and stroke. This review is an update and an extensive analysis of the more recent association studies conducted in stroke. We evaluated a number of studies on several candidate genes (including F5, F2, FGA/FGB/FGG, F7, F13A1, vWF, F12, SERPINE1, ITGB3/PLA1/PLA2/ITGA2B, ITGA2, GP1BA, ACE, AGT, NOS3, APOE, LPL, PON1, PDE4D, ALOX5AP, MTHFR, MTR, and CBS), providing a final panel of genes and molecular variants. We categorized this panel in relation to the degree of association with stroke, supported by the results of meta-analyses and case-control studies. Our findings could represent a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

Polymorphisms and the expression of genes encoding enzymes involved in cardiovascular diseases

BACKGROUND

Atherosclerosis, a multi-factorial disease, is the main determinant of cardiovascular disease (CVD) leading to high mortality and morbidity in westernized countries. Gene polymorphisms and gene expression related to the atherosclerosis process can be identified using a genome-wide approach or looking for candidate disease-causing genes.

METHODS

Using genome wide strategy or candidate gene approach various genes, including paraoxonase genes, which are involved in lipid metabolism, oxidation, inflammation and coagulation, have been associated to atherosclerosis.

CONCLUSION

Evaluation of gene polymorphisms, together with traditional and novel biochemical parameters, may help identify individuals at a high risk for CVD. Genetic characterization of susceptibility genes may also lead to new drugs for atherosclerosis prevention and treatment. In addition, gene expression studies can provide novel insights into the molecular mechanism of lesion development and progression.

Apolipoprotein E polymorphism – a risk factor for metabolic syndrome

BACKGROUND

Metabolic syndrome is closely related to several disturbances in lipid and lipoprotein metabolism. The aim of this study was to determine the association between apolipoprotein E (apoE) genotypes and the risk of metabolic syndrome and/or coronary heart disease complications.

METHODS

The study included 279 subjects divided into three groups: 1) control subjects, 2) metabolic syndrome patients, and 3) obese patients with coronary heart disease. All subjects were characterized by body mass index, and plasma levels of glucose, triglycerides, cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). ApoE genotypes were identified by PCR-restriction fragment length polymorphism using genomic DNA.

RESULTS

Statistical analysis of plasma parameters showed that subjects in groups 2 and 3 had higher levels of triglycerides and lower levels of HDL-C compared to group 1. The frequencies of apoE genotypes determined in this Romanian population (65% for E3/3, 19.6% for E4/3, 9.5% for E3/2, 4.1% for E2/2, 0.6% for E4/4, 1.3% for E4/2) were in agreement with those reported for other Caucasian populations. The distribution of apoE alleles indicated a higher frequency of epsilon4 in groups 2 and 3. There was a higher frequency of the apoE4/3 genotype in groups 2 and 3, which was significantly correlated with higher levels of triglycerides and lower levels of HDL-C.

CONCLUSIONS

Correlations of apoE genotypes with these markers indicate that the epsilon4 allele is an independent risk factor for metabolic syndrome.

Association of lipoprotein lipase S447X, apolipoprotein E exon 4, and apoC3 -455T>C polymorphisms on the susceptibility to diabetic nephropathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. In DN patients, triglyceride (TG) level is elevated and lipoprotein lipase (LPL) activity, which hydrolyzes TG, is decreased. The LPL S447X and apolipoprotein E (APOE) exon 4 polymorphisms affect TG levels, and the APOC3 -455T>C polymorphism affects LPL activity. Our aim was to examine the association of these polymorphisms with nephropathy in type 2 diabetes. We examined these polymorphisms in a case-control study of type 2 diabetic patients including 374 with DN and 392 without DN. LPL 447X-containing genotypes (447X+) were significantly decreased in DN patients [18.6 vs 25.6%, odds ratio (OR) = 0.66, p = 0.02], as were APOE epsilon3/epsilon3 genotypes (64.8 vs 73.1%, OR = 0.68, p = 0.01). In addition, combinations of genotypes [APOE epsilon3/epsilon3 and LPL 447X+ (OR = 0.56), APOC3 CC and LPL 447X+ (OR = 0.31), APOE epsilon3/epsilon3 and APOC3 CC (OR = 0.61] were protective for DN compared with the most common combination of the respective polymorphisms. Our findings suggest the importance of interactions among lipid genes in modulating the risk of DN.