Inflammatory system gene polymorphism and the risk of stroke: A case–control study in an Indian population

The rs11833579 and rs12425791 polymorphisms and risk of ischemic stroke in an Asian population: a meta-analysis

BACKGROUND

In 2009, a GWAS has confirmed that rs11833579 and rs12425791 near the NINJ2 gene could increase the stroke and ischemic stroke (IS) risk. Recently, several studies have been implemented to assess the relationship between the two SNPs and ischemic stroke risk in Asian. However, the results were poorly consistent. To study the association between the both polymorphisms and the risk of ischemic stroke, we performed a meta-analysis.

METHODS

We used odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the strength of association. The heterogeneity was checked by Q test and the inconsistency index (I(2)). Begg's test and Egger's test were used to assess the possible publication bias.

RESULTS

Our study included 6 articles, contained 9 independent case-control studies, involved a total of 9,142 cases and 10,652 controls about rs11833579, 10,165 cases and 11,592 controls about rs12425791. There was a significant association between rs12425791 and IS risk with dominant genetic model (OR=1.087, 95%CI=1.021-1.158, I(2)=34.6%, P=0.152), but not with recessive genetic model and allele A vs. allele G. For rs11833579, we failed to verify it relate with IS risk under allele A vs. allele G, dominant and recessive genetic model.

CONCLUSIONS

This meta-analysis suggest that rs12425791 is relative to ischemic stroke risk under dominant model in Asian population, but not for rs11833579.

Polymorphisms of interleukin-1 and interleukin-6 genes on the risk of ischemic stroke in a meta-analysis

Many epidemiological studies have investigated the associations between polymorphisms of interleukin-1 (IL1) and interleukin-6 (IL6) genes and risk of ischemic stroke (IS), but no conclusions are available because of conflicting results. The aim of this study was to assess the relationships by meta-analysis. The databases of Pubmed, Embase and Wangfang, updated to August 1st, 2011, were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, three case-control studies for IL1α-889C/T, eight studies for IL1β-511C/T, eight studies for IL1-Ra and seven studies for IL6-147G/C were included in this meta-analysis. Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of IS [OR (95% CI)=1.22 (0.85-1.87) for TT vs. CC]. However, when subgroup analyses for countries were conducted, the results indicated that T allele was associated with increased risk of IS for Polish and associated with a trend of increased risk of IS for Chinese although it did not reach statistical significance [TT vs. CC: OR (95% CI)=1.97 (1.22-3.17) for Polish and 1.40 (0.99-1.99) for Chinese]. In addition, overall and subgroup analyses indicated that IL1α-889C/T, IL1-Ra and IL6-147G/C polymorphisms were also not associated with risk of IS [OR (95% CI)=1.21 (0.86-1.70) for TT vs. CC of IL1α-889C/T, 1.22 (0.85-1.75) for RN2/RN2 vs. RN1/RN1 for IL1-Ra and 1.09 (0.84-1.40) for G carriers vs. C carriers for IL6-147G/C]. This study inferred that IL1β-511C/T polymorphism might be moderately associated with increased risk of IS, but no sufficient evidence was available to support any associations between IL1-Ra and IL6-147G/C polymorphisms and IS. We could not draw a conclusion between IL1α-889C/T polymorphism and risk of IS based on the limited data, and further large sample-sized studies were required.

Association of the phosphodiesterase 4D (PDE4D) gene and cardioembolic stroke in an Australian cohort

BACKGROUND

Large-scale epidemiological studies support an important role for susceptibility genes in the pathogenesis of ischemic stroke, with phosphodiesterase 4D identified as the first gene predisposing to ischemic stroke. Several single nucleotide polymorphisms within the phosphodiesterase 4D gene have been implicated in the pathogenesis of stroke. Aim Undertake a multivariate analysis of six single nucleotide polymorphisms within the phosphodiesterase 4D gene in a previously defined Australian stroke cohort, to determine whether these single nucleotide polymorphisms have an association with ischemic stroke.

METHODS

This case-control study was performed using an existing genetic database of 180 ischemic stroke patients and 301 community controls, evaluated previously for cerebrovascular risk factors (hypertension, hypercholesterolemia, diabetes, paroxysmal atrial fibrillation, smoking and history of stroke in a first-degree relative). Based on previously reported associations with large vessel disease, ischemic stroke, cardioembolic stroke or a mixture of these, six single nucleotide polymorphisms in the phosphodiesterase 4D gene were selected for study, these being single nucleotide polymorphisms 13, 19, rs152312, 45, 83 and 87, based on previously utilized DeCODE nomenclature. Single nucleotide polymorphisms were genotyped using a sequence-specific polymerase chain reaction method and gel electrophoresis. Logistic regression was undertaken to determine the relevance of each polymorphism to stroke. Further analysis was undertaken to determine the risk of stroke following stratification for stroke sub-type and etiology.

RESULTS

Significant odds ratios were found to be associated with cardioembolic strokes in two single nucleotide polymorphisms: rs152312 and SNP 45 (P < 0 · 05).

CONCLUSIONS

Our findings demonstrated an association between cardioembolic stroke and phosphodiesterase 4D single nucleotide polymorphisms rs152312 and 45. No significant association was found for the other four single nucleotide polymorphisms investigated within the phosphodiesterase 4D gene. We propose that the results from this Australian population support the concept that a large prospective international study is required to investigate the role of phosphodiesterase 4D in the cardiogenic cause of ischemic stroke.

Meta-analysis of homogeneous subgroups reveals association between PDE4D gene variants and ischemic stroke

BACKGROUND

An Icelandic study showed a significant positive association between phosphodiesterase 4D (PDE4D) gene variants and stroke. However, subsequent studies reported conflicting results, possibly due to small sample sizes and the heterogeneity of the studies.

METHOD

We performed a meta-analysis on 6 SNPs of the PDE4D gene to investigate the association between this gene and ischemic stroke by integrating the results of previous studies, comprising 11,834 cases and 15,233 controls. A pooled genotypic odds ratio (OR) for each SNP was determined under 3 genetic models (i.e. dominant, recessive, and codominant) using both fixed- and random-effects models with consideration for heterogeneity and publication bias across studies.

RESULTS

Among the SNPs included in this study, SNP56 (rs702553) showed the most significant association with ischemic stroke in a meta-analysis comprised of 7 homogenous studies. The overall OR of the TT genotype compared to the AA genotype was 1.29 (95% CI 1.03-1.61; p = 0.022). For SNP83 (rs966221), a protective effect of the ancestral allele T was observed only in Asian populations (ORTT 0.79, 95% CI 0.69-0.90; p = 0.0005). This meta-analysis revealed a significant association of PDE4D gene variants with the risk of ischemic stroke, and further investigations are warranted to evaluate possible ethnic-specific effects.

Genetics of stroke

Stroke is the second most common cause of death and the most common cause of disability in developed countries. Stroke is a multi-factorial disease caused by a combination of environmental and genetic factors. Numerous epidemiologic studies have documented a significant genetic component in the occurrence of strokes. Genes encoding products involved in lipid metabolism, thrombosis, and inflammation are believed to be potential genetic factors for stroke. Although a large group of candidate genes have been studied, most of the epidemiological results are conflicting. Studies of stroke as a monogenic disease have made huge progress, and animal models serve as an indispensable tool to dissect the complex genetics of stroke. In the present review, we provide insight into the role of in vivo stroke models for the study of stroke genetics.

Association of PDE4D and IL-1 gene polymorphism with ischemic stroke in a Han Chinese population

BACKGROUND

The single-nucleotide polymorphisms (SNPs) of the phosphodiesterase 4D (PDE4D) and interleukin-1 (IL-1) genes are associated with increased risk for the development of ischemic stroke (IS) in whites. However, little is known about whether this association could also occur in Han Chinese.

METHOD

A total of 371 patients with IS and unrelated healthy controls were recruited and the SNPs of the PDE4D (83T/C), (87T/C), IL-1 (-889C/T) and IL-1 (-511C/T) were characterized, respectively, by polymerase chain reactions-restriction fragment length polymorphism (PCR-RFLP). The genotype and allele frequencies of these SNPs in this population were statistically analyzed.

RESULTS

The genotype and allele frequencies of the PDE4D (87T/C) and IL-1 (-511C/T) were similar between IS patients and controls. In contrast, the frequencies of CC genotype and C allele of the PDE4D (83T/C) and the T allele frequency of IL-1 (-889C/T) in IS patients were significantly higher than that in healthy controls (p=0.001, p=0.003 and p=0.02, respectively), independent of the conventional risk factors. The values of odds ratio (OR) reached at OR=1.603; 95%CI=1.032-2.489; p=0.036 for the CC genotype of the PDE4D (83T/C) and OR=1.913; 95%CI=1.621-2.375; p=0.034 for the TT genotype of the IL-1 (-889C/T), respectively.

CONCLUSIONS

the SNPs of the PDE4D (83T/C) and IL-1 (-889C/T) were associated with increased risk for the development of IS in Northern Han Chinese.

CD14 C260T promoter polymorphism and the risk of cerebrovascular diseases: a meta-analysis

Cerebrovascular diseases (CVD) are dysfunctions of the brain, resulting from diseases of blood vessels supplying the brain. Atherosclerosis is one of the major underlying causes of CVD, in which inflammation plays a crucial role. One of the inflammatory mechanisms contributing to atherogenesis is the activation of monocytes and macrophages, which could be mediated by the bacterial endotoxin lipopolysaccharide (LPS) via its receptor CD14. The C260T (rs2569190) single-nucleotide polymorphism (SNP) in the promoter region of the CD14 gene was implicated in CVD. To assess the role of this SNP in CVD, a comprehensive meta-analysis of the available genetic data was conducted. All the case-control association studies evaluating the role of CD14 C260T in CVD were identified. Of these, 7 studies (comprising a total of 1488 patients and 1600 control subjects) were included in this meta-analysis. To measure the strength of genetic association for the gene variant, the odds ratios (ORs) were calculated using both fixed and random effects for comparisons of the alleles, the genotypes, and the dominant and recessive genotype models. The results showed there was no significant association between the T allele of C260T and the risk of CVD under the fixed effects model, OR = 0.99 (95% CI (0.89, 1.09)), P = 0.84; or the random effects model, OR = 0.99 (95% CI (0.88, 1.11)), P = 0.83. Similar results were obtained for the homozygotes and the dominant and recessive models. In conclusion, the results of this meta-analysis suggest the CD14 C260T polymorphism is not a risk factor for CVD. However, more studies in ethnically varied populations are needed to evaluate in a reliable manner the role of this SNP in CVD susceptibility.

Advances in the Genetic Basis of Ischemic Stroke

As one of the leading causes of death within both the developed and developing world, stroke is a world-wide problem. About 80% of strokes are ischemic. It is caused by multiple genetic factors, environmental factors, and interactions among these factors. There is a long list of candidate genes that have been studied for a possible association with ischemic stroke. Among the most widely investigated genes are those involved in haemostasis, inflammation, nitric oxide production, homocysteine and lipid metabolism, renin-angiotensin-aldosterone system. Combined link-age/association studies have demonstrated that genes encoding PDE4D and ALOX5AP confer risk for stroke. We review the studies of these genes which may have potential application on the early diagnosis, prevention and treatment ischemic stroke patients.

Association between inflammatory gene polymorphisms and coronary artery disease in an Indian population

BACKGROUND

Inflammation is one of the major components of atherosclerosis which is the underlying disorder that leads to various diseases including coronary artery disease (CAD). Genes that are involved in the inflammatory processes are therefore good candidates for the risk of CAD. Variations in the genes involved in various molecular pathways of inflammation have been implicated to exaggerated atherosclerosis and the risk of cardiovascular diseases. In this study, we performed a genetic association study on the single nucleotide polymorphisms (SNPs) present in the genes CD14 (-159 C/T), TNFalpha (-308 G/A), IL-1alpha (-889 C/T), IL-6 (-174 G/C), PSMA6 (-8 C/G), and PDE4D (SNP83 T/C, respectively) in order to discern their possible role in the susceptibility to CAD in a North Indian population.

METHODS

Angiographically proven CAD patients (n = 210) and age, sex and ethnically matched normal healthy controls (n = 232) were recruited for this case-control study. Genotypes were determined by PCR-RFLP method. Chi-square and logistic regression analyses were performed to compare the genotype and allele frequencies between the patient and the control groups.

RESULTS

None of the SNPs showed significant association with CAD in the study population before and after adjustment for the confounding risk factors like age, sex, hypertension, smoking habit, and diabetes.

CONCLUSION

This study was unable to demonstrate any association between the six gene variants tested and CAD in the North Indian population.