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

The link between Alzheimer's disease and stroke: A detrimental synergism

Being age-related disorders, both Alzheimer's disease (AD) and stroke share multiple risk factors, such as hypertension, smoking, diabetes, and apolipoprotein E (APOE) Ɛ4 genotype, and coexist in patients. Accumulation of amyloid-β plaques and neurofibrillary tangled impair cognitive potential, leading to AD. Blocked blood flow in the neuronal tissues, causes neurodegeneration and cell death in stroke. AD is commonly characterized by cerebral amyloid angiopathy, which significantly elevates the risk of hemorrhagic stroke. Patients with AD and stroke have been both reported to exhibit greater cognitive impairment, followed by multiple pathophysiological mechanisms shared between the two. The manuscript aims to elucidate the relationship between AD and stroke, as well as the common pathways and risk factors while understanding the preventive therapies that might limit the negative impacts of this correlation, with diagnostic modalities and current AD treatments. The authors provide a comprehensive review of the link and aid the healthcare professionals to identify suitable targets and risk factors, that may retard cognitive decline and neurodegeneration in patients. However, more intricate research is required in this regard and an interdisciplinary approach that would target both the vascular and neurodegenerative factors would improve the quality of life in AD patients.

Phosphodiesterase 4 D (PDE4D) gene polymorphisms and risk of ischemic stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Studies on the relationship between Phosphodiesterase 4 D (PDE4D) gene polymorphism with the risk of ischemic stroke (IS) have shown discordant results. The present meta-analysis was aimed to clarify the relationship between PDE4D gene polymorphism with the risk of IS by estimating pooled analysis of published epidemiological studies.

METHODS

A comprehensive literature search for all the published articles was performed in various electronic databases, including PubMed, EMbase, Cochrane Library, Trip Database, Worldwide Science, CINAHL, and Google Scholar up to 22nd December 2021. Pooled Odds ratios (ORs) with 95% Confidence Intervals (CIs) under dominant, recessive, and allelic models were calculated. Subgroup analysis based on ethnicity (Caucasian vs. Asian) was performed to examine the reliability of these findings. Sensitivity analysis was also performed to detect the heterogeneity between studies. Finally, Begg's funnel plot was used to assess the potential for publication bias.

RESULTS

In our meta-analysis, we identified a total of 47 case-control studies with 20,644 ischemic stroke (IS) cases and 23,201 control subjects, including 17 studies of Caucasian descent and 30 studies of Asian descent. Our findings suggest that there was a significant relationship between SNP45 gene polymorphism and risk of IS (Recessive model: OR = 2.06, 95% CI 1.31-3.23), SNP83 overall (allelic model: OR = 1.22, 95% CI 1.04-1.42), Asian (allelic model: OR = 1.20, 95% CI 1.05-1.37), and SNP89 Asian (Dominant model: OR = 1.43, 95% CI 1.29-1.59, recessive model: OR = 1.42, 95% CI 1.28-1.58) respectively. However, no significant relationship was found between SNP32, SNP41, SNP26, SNP56, and SNP87 gene polymorphisms and risk of IS.

CONCLUSION

Findings of this meta-analysis conclude that SNP45, SNP83, and SNP89 polymorphism could be capable of increasing stroke susceptibility in Asians but not in the Caucasian population. Genotyping of SNP 45, 83, 89 polymorphisms may be used as a predictor for the occurrence of IS.

Association of plaque enhancement on vessel wall MRI and the phosphodiesterase 4D variant with stroke recurrence in patients with symptomatic intracranial atherosclerosis

PURPOSE

Vessel wall MRI (VW-MRI) can be used to evaluate the nature of intracranial atherosclerosis (ICAS) plaque in vivo. Phosphodiesterase 4D (PDE4D) participates in stroke development. This study aims to explore the value of VW-MRI findings and the PDE4D gene variant in predicting stroke recurrence in patients with ICAS.

METHODS

We prospectively recruited 324 symptomatic ICAS patients. VW-MRI was performed to determine luminal and wall changes. PDE4D gene single-nucleotide polymorphisms (SNPs)-namely, SNP32, SNP83, and SNP87-were determined by direct sequencing. The risk factors of stroke recurrence were analyzed using the multivariate Cox proportional hazards model.

RESULTS

Of the 324 subjects, 97 (29.9%) experienced recurrent ischemic stroke during the follow-up period. A total of 254 patients (78.4%) showed plaque enhancement; 87 of these patients experienced stroke recurrence. The CT/CC genotype frequencies of PDE4D83 were significantly higher in participants with recurrent stroke than in patients without stroke recurrence (p = 0.019 and p < 0.001, respectively). However, the PDE4D32 and PDE4D87 variants were not correlated with recurrent stroke. Multivariate analysis showed that plaque enhancement from VW-MRI (HR 4.52, 95% CI 2.35-8.73, p < 0.001) and the PDE4D83 variant (HR 7.43, 95% CI 1.75-31.87, p = 0.005) were independently correlated with stroke recurrence. Kaplan-Meier curves showed significant differences in stroke recurrence rates between the plaque-enhanced group and the non-enhanced group (p < 0.001) and between the PDE4D83 variant carriers and noncarriers (p = 0.002).

CONCLUSION

Plaque enhancement on VW-MRI and the presence of the PDE4D83 variant are associated with ischemic stroke recurrence in subjects with symptomatic ICAS.

TNF-α (G-308A) Polymorphism, Circulating Levels of TNF-α and IGF-1: Risk Factors for Ischemic Stroke—An Updated Meta-Analysis

Objective

Accumulated studies have explored gene polymorphisms and circulating levels of tumor necrosis factor (TNF)-α and insulin-like growth factor (IGF)-1 in the etiology of ischemic stroke (IS). Of the numerous etiopathological factors for IS, a single-nucleotide polymorphism (SNP) rs1800629 located in the TNF-α gene promoter region and increased levels of TNF-α were found to be associated with IS in different ethnic backgrounds. However, the published results are inconsistent and inconclusive. The primary objective of this meta-analysis was to investigate the concordance between rs1800629 polymorphism and IS. A secondary aim was to explore circulating levels of TNF-α and IGF-1 with IS in different ethnic backgrounds and different sourced specimens.

Methods

In this study, we examined whether rs1800629 genetic variant and levels of TNF-α and IGF-1 were related to the etiology of IS by performing a meta-analysis. Relevant case-control studies were retrieved by database searching and systematically selected according to established inclusion criteria.

Results

A total of 47 articles were identified that explored the relationship between the rs1800629 polymorphism and levels of TNF-α and IGF-1 with IS risk susceptibility. Statistical analyses revealed a significant association between the rs1800629 polymorphism and levels of TNF-α and IGF-1 with IS pathogenesis.

Conclusion

Our findings demonstrated that the TNF-α rs1800629 polymorphism, the increased levels of TNF-α, and decreased levels of IGF-1 were involved in the etiology of IS.

Association of Interleukin-6-174G/C Polymorphism With Ischemic Stroke: An Updated Meta-Analysis

Background: Although numerous epidemiological studies have investigated the association between -174G/C(rs1800795) polymorphism in the interleukin-6 (IL-6) gene-stimulatory region and the risk of ischemic stroke (IS), they failed to reach a unified conclusion. The true relationship between -174G/C(rs1800795) polymorphism and IS remains controversial and unclear. Therefore, in this meta-analysis, we aimed to analyze more precisely the association between -174G/C(rs1800795) single-nucleotide polymorphism (SNP) of IL-6 gene and IS in a larger pooled population. Methods: A comprehensive literature search was performed in PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials until June 30, 2021. A fixed or random-effects model was utilized based on heterogeneity between studies. The odds ratios (ORs) and 95% confidence intervals (Cis) were calculated in the models of allele comparison (G vs. C), homozygote comparison (GG vs. CC) and (GC vs. CC), dominant (GG vs. GC + CC), hyper dominant (GG + CC vs. GC), and recessive (GG + GC vs. CC) to determine the strength of associations. Results: This meta-analysis included 13 case-control studies in 35 articles with 5,548 individuals. Overall, no significant associations between IL-6 -174G/C(rs1800795) and IS were identified (G vs. C:OR [95% CI] = 0.99 [0.81, 1.21], P = 0.91; GG + CC vs. GC:0.97 [0.85, 1.11], P = 0.66; GG vs. GC + CC: 1.01 [0.81, 1.25], P = 0.94; GC vs. CC: OR [95% CI] = 1.01 [0.68, 1.5], P = 0.96; GG vs. CC:0.93 [0.57, 1.51], P = 0.76; GG + GC vs. CC:0.97 [0.64, 1.47], P = 0.89). In the subgroup analyses by ethnicity or HWE P-value, there was a statistically significant association between IL-6 -174G/C(rs1800795) polymorphisms and IS in the alleles model; (G vs. C: LogOR [95% CI] = 0.14 [-0.16,.45], P = 0.00), homozygote model (GG vs. CC: LogOR [95% CI] = 0.18 [-0.58,.95], P = 0.00) and (GC vs. CC: LogOR [95% CI] = 0.2 [-0.46,.85], P = 0.00), dominant model (GG vs. GC + CC: OR [95% CI] = 0.02 [-0.72, 0.77], P = 0.00), and recessive model (GG + GC vs. CC: OR [95% CI]= -0.17 [-0.86,.52], P = 0.00) of the European population and in the dominant model (GG vs. GC + CC: OR [95% CI] = -0.13 [-0.51, 0.24]) of the Asian population. No statistical significance was identified in both six models of HWE p ≥ 0.2 group (both P ≥ 0.05). Conclusion: This meta-analysis revealed no correlation between IL-6 -174G/C(rs1800795) polymorphism and IS, whereas the subgroup analysis indicated that the relationship between IL-6 -174G/C(rs1800795) polymorphism and IS susceptibility varied significantly according to ethnicity and geography.

circ_0023461 Silencing Protects Cardiomyocytes from Hypoxia-Induced Dysfunction through Targeting miR-370-3p/PDE4D Signaling

Background

Acute myocardial infarction (AMI) is a common cardiovascular disease with high disability and mortality. Circular RNAs (circRNAs) are implicated in the pathomechanism of multiple human diseases, including AMI. This study intended to explore the function and working mechanism of a novel circRNA circ_0023461 in hypoxia-induced cardiomyocytes.

Methods

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were implemented to detect RNA and protein expression. Cell counting kit-8 (CCK8) assay and 5-ethynyl-2'-deoxyuridine (Edu) assay were conducted to analyze cell viability and proliferation ability. Cell migration and apoptosis were assessed by Transwell assay and flow cytometry. Cell oxidative stress was analyzed using the commercial kits. Enzyme-linked immunosorbent assay (ELISA) was conducted to analyze cell inflammation. Cell glycolytic metabolism was evaluated using the commercial kits. Dual-luciferase reporter assay and RNA pull-down assay were conducted to verify the intermolecular interactions.

Results

circ_0023461 expression was upregulated in AMI patients and hypoxia-induced AC16 cells. Hypoxia restrained the viability, proliferation, migration, and glycolysis and induced the apoptosis, oxidative stress, and inflammation of AC16 cells, and these effects were attenuated by the silence of circ_0023461. MicroRNA-370-3p (miR-370-3p) was verified as a target of circ_0023461, and circ_0023461 silencing-mediated protective effects in hypoxia-induced cardiomyocytes were partly alleviated by the knockdown of miR-370-3p. miR-370-3p interacted with the 3' untranslated region (3' UTR) of phosphodiesterase 4D (PDE4D), and PDE4D overexpression partly reversed miR-370-3p overexpression-induced protective effects in hypoxia-induced cardiomyocytes. circ_0023461 can upregulate PDE4D expression by acting as a molecular sponge for miR-370-3p in AC16 cells.

Conclusion

circ_0023461 knockdown attenuated hypoxia-induced dysfunction in AC16 cells partly by targeting the miR-370-3p/PDE4D axis.

Promoter polymorphism of TNF-α (rs1800629) is associated with ischemic stroke susceptibility in a southern Thai population

Stroke represents the leading cause of disability and mortality amongst the elderly worldwide. Multiple risk factors, including both genetic and non-genetic components, as well as their interactions, are proposed as etiological factors involved in the development of ischemic stroke (IS). Promoter polymorphisms of the IL-6-174G/C (rs1800795) and TNF-α-308G/A (rs1800629) genes have been considered as predictive risk factors of IS; however, these have not yet been evaluated in a Thai population. The aims of this study were to investigate the association of IL-6-174G/C and TNF-α-308G/A polymorphisms with IS. Genomic DNA from 200 patients with IS and 200 controls were genotyped for IL-6-174G/C and TNF-α-308G/A polymorphisms using TaqMan™ SNP genotyping and quantitative PCR-high resolution melting analysis, respectively. It was found that the TNF-α-308 A allele was significantly associated with an increased risk of IS development compared with the G allele [odds ratio (OR)=2.044; 95% CI=1.154-3.620; P=0.014]. Moreover, the IS risk was significantly higher in the presence of TNF-α-308 GA or AA genotypes compared with that in the presence of GG genotypes with a dominant inheritance (OR=1.971; 95% CI=1.080-3.599; P=0.027). However, there was no association between IL-6-174G/C and the risk of IS development. The interaction study demonstrated that IL-6-174 GG and TNF-α-308 GG genotypes enhanced IS susceptibility when combined with hypertension, hyperlipidemia and alcohol consumption. Hypertensive and hyperlipidemic subjects with the TNF-α-308 GA and AA genotypes were more likely to develop IS compared with those who did not have these two conditions and had the GG genotype. In a matched study design (1:1), the IL-6-174 GC genotype was associated with higher IL-6 levels in the control group. Collectively, the present results highlight the utility of the TNF-α-308G/A polymorphism as a predictive genetic risk factor for development of IS.

Interleukin 6 (rs1800795) gene polymorphism is associated with cardiovascular diseases: a meta-analysis of 74 studies with 86,229 subjects

Cardiovascular diseases (CVD) are group of complex and multifactorial pathologies, in which interleukin-6 (IL-6) gene polymorphisms have been associated with several components of the CVD. Thus, in this study, we thoroughly reviewed and meta-analyzed evidence on the association between the IL-6 (rs1800795) gene polymorphism and CVD. We systematically searched in the PubMed, Web of Sciences, and Scopus databases. The analyses were performed using five study groups based on (1) a combined pool of the overall populations, (2) the country of birth, (3) the continent of birth, (4) the diagnosis and (5) both location (country or continent) and diagnosis. The analysis included the allelic, homozygote, heterozygote, dominant and recessive models. The meta-analysis showed that -174G>C (rs1800795) is a risk factor for CVD (allelic: OR=1.06, CI 95%=1.02-1.10. Z p value <0.0001; homozygous: OR=1.11, CI 95%=1.03-1.19, Z p value= 0.002; heterozygous: OR=1.08, CI 95%=1.03-1.21, Z p value= 0.003; dominant: OR= 1.12, CI 95%= 1.07-1.18, Z p value= 0.001) and that this risk increases in the Chinese population. Additionally, we found that carriers of the C allele of 174G>C (rs1800795) polymorphism have an increase in the risk of coronary artery disease under the hereditary models assessed in the study. Using robust data, we found that IL-6 (rs1800795) -174G>C gene polymorphism is associated with CVD risk.

Association between CD14 rs2569190 C>T polymorphism and ischemic stroke susceptibility: a meta-analysis based on 5,277 subjects

INTRODUCTION

Previous epidemiological studies have suggested that CD14 rs2569190 C>T polymorphism plays an important role in ischemic stroke (IS) risk, but the results were inconsistent. Therefore, we conducted a meta-analysis to determine the association between CD14 rs2569190 C>T polymorphism and IS susceptibility.

METHODS

Online databases were searched from inception up to July 1, 2018, for studies concerning CD14 rs2569190 C>T polymorphism and its association with IS susceptibility. ORs and corresponding 95% CIs were calculated in the genetic models of each polymorphism locus with Stata Version 14.0. Furthermore, heterogeneity, meta-regression, accumulative analyses, sensitivity analyses, and publication bias were examined.

RESULTS

Overall, 10 observed studies involving 5,277 subjects were included in this meta-analysis on CD14 rs2569190 C>T polymorphism. Generally, no significant associations were found between CD14 rs2569190 C>T polymorphism and IS risk (allele contrast of T vs C: OR =1.03, 95% CI =0.96-1.12, P=0.41, I2=27.8%; co-dominant models of CT vs CC: OR =1.01, 95% CI =0.81-1.25, P=0.95, I2=51.9%; co-dominant models of TT vs CC: OR =1.04, 95% CI =0.89-1.22, P=0.62, I2=25.1%; dominant model of CT + TT vs CC: OR =1.02, 95% CI =0.84-1.25, P=0.82, I2=51.4%; recessive model of TT vs CC + CT: OR =1.07, 95% CI =0.95-1.22, P=0.28, I2=0%), similar to the results in the subgroup analysis.

CONCLUSION

The current evidence indicated that CD14 rs2569190 C>T polymorphism was not a critical risk factor for IS development.

LncRNA XIST regulates myocardial infarction by targeting miR-130a-3p

The study was used to probe long noncoding RNA X-inactive specific transcript (lncRNA XIST) RNA expression profile and its influence on cell cycle, proliferation, and apoptosis in myocardial cells. We also aimed to explore the possible meditating relationship between XIST, PDE4D, and miR-130a-3p. Gene differential analysis was carried out using human lncRNA Microarray V3.0. quantitative real-time PCR was used to test mRNA expressions of XIST, miR-130a-3p, and PDE4D in normal cells and postmyocardial infarction (MI) cells. Western blot was applied to determine the protein expression profile of PED4D. Changes in viability and cell cycle/apoptosis of post-MI myocardial cells after silencing of XIST or PDE4D were investigated by MTT assay and flow cytometry, respectively. The targeting relationship between miR-130a-3p and XIST, PDE4D in myocardial cells were verified by dual luciferase reporter assay. Simulated MI environment was constructed by performing anoxic preconditioning in normal cells to probe the influence of XIST on myocardial cell apoptosis. XIST and PDE4D were overexpressed in post-MI myocardial cells, whereas miR-130a-3p was underexpressed in post-MI myocardial cells. High-expressed XIST and PDE4D both promoted myocardial cell apoptosis. High-expressed XIST also inhibited myocardial cell proliferation. XIST-downregulated miR-130a-3p and PDE4D was a direct target of miR-130a-3p. LncRNA XIST promotes MI by targeting miR-130a-3p. MI induced by PDE4D can be reversed by miR-130a-3p.

Association between PDE4D rs966221 polymorphism and risk of ischemic stroke: a systematic review and meta-analysis

PDE4D polymorphism (SNP83/rs966221) was reported to be associated with the susceptibility to ischemic stroke (IS), however, the results were inconclusive. An electronic search of Embase, PubMed, CNKI and Wan Fang Date was performed to identify relevant studies published throughout April 2017. A total of 26 studies were enrolled in the analysis. No significant association between the rs9662221 polymorphism and IS was observed in the overall analysis. Nevertheless, in the subgroup analysis, our results showed a significant association between the SNP83 polymorphism and IS in CC+ CT vs. TT (OR = 1.19, 95% CI: 1.02-1.38), CT vs.TT (OR = 1.14, 95% CI: 1.01-1.29) and C vs. T (OR = 1.25, 95% CI: 1.06-1.48) in Asian population. But we did not found any association in CC vs. CT + TT (OR = 1.2, 95% CI: 0.9-1.61) and CC vs. TT (OR = 1.26, 95% CI: 0.91-1.75) in the Asian populations. Meantime, no significant correlations were observed under the five genetic model in Caucasian population (p > 0.05). In conclusion, our meta-analysis demonstrated that the SNP83 polymorphism in the PDE4D gene might contribute to IS susceptibility especially in Asian populations. Whereas the relationship of the polymorphism to the disease in Caucasian population was still in controversial. In future, additional well designed studies with larger sample sizes are still required to further elucidate this association.

Stroke, Vascular Dementia, and Alzheimer's Disease: Molecular Links

Stroke is a brain disease that occurs when blood flow stops, resulting in reduced oxygen supply to neurons. Stroke occurs at any time and at any age, but increases after the age of 55. It is the second leading cause of death and the third leading cause of disability-adjusted, life-years. The pathophysiology of ischemic stroke is complex and recent molecular, cellular, and animal models and postmortem brain studies have revealed that multiple cellular changes have been implicated, including oxidative stress/mitochondrial dysfunction, inflammatory responses, micro RNA alterations, and marked changes in brain proteins. These cellular changes provide new information for developing therapeutic strategies for ischemic stroke treatment. Research also revealed that stroke increases with a number of modifiable factors and most strokes can be prevented and/or controlled through pharmacological or surgical interventions and lifestyle changes. Ischemic stroke is the major risk factor for vascular dementia and Alzheimer's disease. This review summarizes the latest research findings on stroke, including causal factors and molecular links between stroke and vascular disease/Alzheimer's disease.

Functional polymorphism rs3783553 in the 3'-untranslated region of IL-1A increased the risk of ischemic stroke: A case-control study

Accumulating evidence indicates interleukin-1 (IL-1) is a critical mediator of inflammatory responses in ischemic stroke (IS). The aim of this study was to investigate whether rs3783553 in the 3'-untranslated region of IL-1A was associated with the risk of IS. In this hospital-based case-control study, we genotyped the rs3783553 using polymerase chain reaction in 316 patients with IS and 332 age, sex, and ethnicity-matched controls. Plasma level of IL-1α was measured by enzyme-linked immunosorbent assay. The relative luciferase activities were measured by the Dual Luciferase assay system. The presence of ins/ins genotype was associated with higher odds ratios (ORs) of IS compared with del/del genotype (ins/ins vs del/del: adjusted OR 1.77, 95% confidence interval [CI] 1.06-2.98; recessive model: adjusted OR 1.69, 95% CI 1.06-2.70). The higher risk of IS was also observed in allele comparison (adjusted OR 1.29, 95% CI 1.00-1.65). Multivariate logistic regression analysis showed that age, hypertension, total cholesterol, triglyceride, low-density lipoprotein, and rs3783553ins/ins genotypes were independent risk factors for IS. Plasma level of IL-1α was higher among IS patients compared with controls (P = .03). Notably, IS patients with the TTCA/TTCA genotype had a higher level of IL-1α compared with those with the del/del genotype (P = .01). Luciferase reporter assay showed that the vector containing the TTCA del allele exhibited a reduced transcriptional activity in the presence of miR-122 and miR-378. These findings indicate that IL-1A rs3783553 ins/ins genotype may increase the susceptibility to IS, possibly by interrupting the binding site of miR-122 and miR-378.

Association of IL-10-1082A/G Polymorphism with Ischemic Stroke: Evidence from a Case-Control Study to an Updated Meta-Analysis

BACKGROUND AND AIMS

Interleukin-10 (IL-10) plays a vital part in the pathophysiology of vascular inflammation. Several studies have investigated the potential association between the IL-10-1082A/G polymorphism and the risk of ischemic stroke where the inflammatory process is involved, but the conclusions have been inconsistent.

METHODS

Three hundred eighty-six ischemic stroke patients and 386 healthy controls were recruited in the study. Genotyping was conducted by using the polymerase chain reaction-ligation detection reaction method. A meta-analysis was then performed by pooling our data with previous published studies.

RESULTS

In our case-control study, a lack of association was revealed between IL-10-1082A/G and ischemic stroke (p > 0.05). When combined with previous studies, however, a significant relationship between IL-10-1082A/G and ischemic stroke risk was found (G vs. A: OR = 0.73, 95% CI = 0.60-0.88, p < 0.01; GG vs. AA: OR = 0.61, 95% CI = 0.49-0.76, p < 0.01; GG+AG vs. AA: OR = 0.70, 95% CI = 0.54-0.91, p < 0.01; GG vs. AG+AA: OR = 0.68, 95% CI = 0.52-0.89, p < 0.01), as well as in subgroup analyses. Sensitivity analysis and publication bias assessment supported the reliability of the results from the meta-analysis.

CONCLUSIONS

Evidence from a case-control study to an updated meta-analysis suggests that the IL-10-1082A/G polymorphism is associated with ischemic stroke susceptibility.

Association between genetic polymorphisms of interleukins and cerebral infarction risk: a meta-analysis

Interleukins (ILs) are the most typical inflammatory and immunoregulatory cytokines. Evidences have shown that polymorphisms in ILs are associated with cerebral infarction risk. However, the results remain inconclusive. The present study was to evaluate the role of ILs polymorphisms in cerebral infarction susceptibility. Relevant case-control studies published between January 2000 and December 2015 were searched and retrieved from the electronic databases of Web of Science, PubMed, Embase and the Chinese Biomedical Database. The odds ratio (OR) with its 95% confidence interval (CI) were employed to calculate the strength of association. A total of 55 articles including 12619 cerebral infarction patients and 14436 controls were screened out. Four ILs (IL-1, IL-6, IL-10 and IL-18) contained nine single nucleotide polymorphisms (SNPs; IL-1α -899C/T, IL-1β -511C/T and IL-1β +3953C/T; IL-6 -174G/C and -572C/G; IL-10 -819C/T and -1082A/G; IL-18 -607C/A and -137G/C). Our result showed that IL-1α -899C/T and IL-18 -607C/A (under all the genetic models), and IL-6 -572C/G (under the allelic model, heterogeneity model and dominant model) were associated with increased the risk of cerebral infarction (P<0.05). Subgroup analysis by ethnicity showed that IL-6 -174G/C polymorphism (under all the five models) and IL-10 -1082A/G polymorphism (under the allelic model and heterologous model) were significantly associated with increased the cerebral infarction risk in Asians. Other genetic polymorphisms were not related with cerebral infarction susceptibility under any genetic models. In conclusion, IL-1α -899C/T, IL-6 -572C/G and IL-18 -607C/A might be risk factors for cerebral infarction development. Further studies with well-designed and large sample size are still required.

Promoter Polymorphism (-174, G/C) of Interleukin-6 and Arterial Thromboembolic Events: A Meta-Analysis

Background

Ischemic stroke and myocardial infarction are fatal diseases and are among the top 10 causes of death in Korea, including arterial thromboembolic events. Many previous studies have described the function of interleukin-6 (IL-6) in arterial thromboembolic events and the association between promoter single-nucleotide polymorphism (SNP) (rs1800795; −174, G/C) of the IL-6 gene. However, these results were controversial. Therefore, we performed a meta-analysis to more precisely assess the association between the SNP of the IL-6 gene and susceptibility to arterial thromboembolic events.

Material/Methods

We used PubMed, Embase, Google Scholar, and Korean Studies Information Service System (KISS) electronic databases. Comprehensive Meta-analysis software (Corporation, NJ) was used to evaluate the relationship between rs1800795 SNP of IL-6 gene and risk of arterial thromboembolic events. Odds ratio (OR), 95% confidence interval (CI), and P value were also calculated. The 13 eligible studies were analyzed in the meta-analysis.

Results

The present meta-analysis found that rs1800795 SNP of IL-6 gene is not significantly associated with susceptibility to arterial thromboembolic events (C allele vs. G allele, OR=1.04, 95% CI=0.91–1.19, P=0.619; CC vs. CG+GG, OR=1.09, 95% CI=0.91–1.31, P=0.364; CC+CG vs. GG, OR=0.97, 95% CI=0.78–1.21, P=0.763, respectively), and the SNP of IL-6 gene also did not show any significant association with ischemic stroke or myocardial infarction (P>0.05 in each model).

Conclusions

We found that rs1800795 SNP of IL-6 gene was not related to arterial thromboembolic events. However, further study will be needed to confirm these results.

Relationship between Interleukin-6 (-174G/C and -572C/G) Promoter Gene Polymorphisms and Risk of Intracerebral Hemorrhage: A Meta-Analysis

BACKGROUND

Polymorphisms of -174G/C and -572C/G in the Interleukin-6 (IL-6) promoter gene can affect both transcription and secretion of IL-6 and may be involved in the inflammatory mechanisms in early and delayed phases after intracerebral hemorrhage (ICH). The role of these polymorphisms remains unclear for the pathogenesis of ICH.

METHODS

PubMed, EMBASE, MEDLINE and Google Scholar searches were conducted from January 1, 1950 to February 29, 2016 and were supplemented with relevant articles identified in the references. The following search terms were used: ('interleukin-6' or 'IL-6') and ('genetic polymorphism' or 'single nucleotide polymorphisms' or 'SNP') and ('intracerebral hemorrhage' or 'ICH') and ('hemorrhagic stroke' or 'HS'). Fixed or random effects models were used to estimate the pooled odds ratios and 95% confidence intervals. Begg's funnel plot was used to assess the potential for publication bias.

RESULTS

In our meta-analysis, three case-control studies involving 446 ICH cases and 2,322 controls were included. No significant association was observed for the IL-6 (-174G/C and -572C/G) gene polymorphisms with the risk of ICH under dominant, recessive and allelic models.

CONCLUSION

Our meta-analysis suggests that IL-6 gene polymorphisms are not associated with the risk of ICH. However, caution must be taken while considering the results of our meta-analysis due to the presence of small sample size. Our results cannot be extrapolated to represent the effect of entire IL-6 genetic polymorphism on stroke patients worldwide. Therefore, further well-designed studies with large sample size are warranted to validate our findings and provide a profound conclusion.

MTHFR (C677T) CT genotype and CT-apoE3/3 genotypic combination predisposes the risk of ischemic stroke

The predisposition to ischemic stroke (IS) might involve interactions of several genes and environmental factors. The present study was aimed to evaluate the influence of polymorphisms in methylenetetrahydrofolate reductase (MTHFR-C677T) and apolipoprotein-E (apo-E) as risk factors for IS patients in south Indian population. 200 IS patients and 193 age and sex matched controls were genotyped for MTHFR-C677T and apoE by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Statistically significant association was observed for MTHFR CT genotype (IS-Pooled: OR=4.29; p=5.01×10(-5); IS-Males: OR=4.13; p=0.001; IS-Females: OR=8.62; p=0.027; IS-Large Vessel Disease (LVD)- Pooled: OR=4.14; p=0.0002) and T allele (IS-Pooled: OR=4.82; p=1.49×10(-5); IS-Males: OR=4.33; p=0.0002; IS-Females: OR=7.99; p=0.031; IS-LVD-Pooled: OR=4.13; p=0.0001). Further, reduced frequencies of CC genotype (IS-Pooled: OR=0.20; p=9.80×10(-6); IS-Males: OR=0.25; p=0.001; IS-Females: OR=0.12; p=0.027; IS-LVD-Pooled: OR=0.23; p=0.0001) and C allele (IS-Pooled: OR=0.21; p=1.49×10(-5); IS-Males: OR=0.23; p=0.0002; IS-Females: OR=0.13; p=0.031; IS-LVD-Pooled: OR=0.24; p=0.0001) were observed in IS patients than the controls. No association was observed for apoE genotypes/alleles in IS/LVD cases. Our study demonstrated the presence of risk for MTHFR CT genotype/T allele and 'CT-3/3' (n=33 vs. 5; OR=7.42; p=0.001) genotypic combination in the development of IS in south India. Further, follow-up study of these stroke cases i.e., in later stages of the disease whether they are developing the neurological disorders such as Alzheimer's Disease (AD) and vascular dementia (VaD) is needed to draw a fruitful conclusion in connection between neurological disorders and with these two polymorphisms, before translating it into clinical practice.

Association between the interleukin-6 genetic polymorphism 174 G/C and thrombosis disorder risk: Meta-analysis of 10,549 cases and 19,316 controls

Studies investigating the association between interleukin-6 (IL-6) gene-174 G/C polymorphism (rs1800795) and thrombosis disorder risk reported conflicting results. The aim of our study was to assess the association between the IL-6 gene 174 G/C polymorphisms and the risk of thrombosis disorders.Thirty four case-control studies in 29 articles with 29,865 individuals were incorporated in this meta-analysis by searching the public databases including Medline, Embase, and ISI Web of Science databases as of June 1st, 2015. The odds ratio (OR) and 95% confidence interval (95%CI) were used to assess the strength of the association.By pooling all studies, there was marginal association between and the risk of thrombotic disorders (1.09[0.97-1.22]), arterial thrombotic disorders (1.08[0.95-1.23]), and myocardial infarction (MI, 1.14[0.99-1.32]) under dominant genetic effect (C carriers vs GG). In subgroup analyses stratified by ethnicity, study scale, thrombotic category, and country, the results indicated that IL-6 gene-174 G/C polymorphism was significantly associated with increased risk of thrombotic disorders given the conditional such as Asians, large sample-sized, MI, population-based, and Indian studies (C carriers vs GG: 1.39 [1.13-1.72] and C allele vs G allele: 1.36 [1.18-1.56] for Asian; C carriers vs GG: 1.15 [1.01-1.31] and C allele vs G allele: 1.12 [1.01-1.23] for large sample-sized studies; C allele vs G allele: 1.10 [1.03-1.18] for population-based studies; and C carriers vs GG: 1.40 [1.19-1.65] for Indian studies). We did not observe significant association between IL-6-174 G/C and the risk of Caucasians, small sample-sized studies, stroke and venous studies, and other country studies.This meta-analysis suggests that IL-6 gene-174 G/C polymorphism may be marginally associated with risk of thrombotic disorders, arterial disorders, MI especially for Asian, Indian, population-based, and large sample-sized studies. More studies with larger sample size and well-designed studies might be warranted.

Influence of the Cyclooxygenase-2 Gene -765G/C and -1195G/A Polymorphisms on Development of Ischemic Stroke

BACKGROUND

Many studies have investigated the association between the cyclooxygenase-2 (COX-2) gene polymorphism and ischemic stroke. However, results of these studies still remain controversial. To better explain the association between COX-2 polymorphisms (-765G/C and -1195G/A) and ischemic stroke risk, a meta-analysis was performed.

METHODS

Relevant studies were identified from 4 Chinese databases (Chinese Biological Medical Literature database, Chinese National Knowledge Infrastructure database, Chongqing VIP database, and Chinese WANFANG database), PUBMED and EMBASE prior to December 2015. The strength of association between COX-2 polymorphism and ischemic stroke was evaluated by the odds ratio (OR) with 95% confidence interval (CI). Inconsistency index (I(2)) and the Cochran's Q statistic were used to check heterogeneity. Publication bias was evaluated by funnel plots and Egger's regression test.

RESULTS

A total of 4086 ischemic stroke cases and 4747 controls were identified. Significant association between COX-2 -765G/C polymorphism and the risk of ischemic stroke was found in Brazilians and the African-Americans. The OR of (CC+GC versus GG) for the Brazilians and African-Americans were (6.328, 95% CI = 2.295-17.448) and (1.644, 95% CI = 1.060-2.551). In addition, the recessive model of the Brazilians gave an OR of 3.621 (95% CI: 1.519-8.630). Furthermore, the (GC versus GG) and the allele model of the African-Americans were (OR: 1.615, 95% CI = 1.015-2.572) and (OR: 1.422, 95% CI = 1.033-1.957). Significant association was also observed for COX-2 -1195G/A polymorphism in the subtypes of small vessel disease (SVD) of ischemic stroke.

CONCLUSIONS

Our study suggests that COX-2 -765G/C and -1195G/A polymorphisms may contribute to susceptibility of ischemic stroke, specifically in Brazilians and the African-Americans, and those of SVD.

Genetic association between inflammatory genes (IL-1α, CD14, LGALS2, PSMA6) and risk of ischemic stroke: A meta-analysis

BACKGROUND

Sequence variations in genes involved in inflammatory system are known to contribute to the risk of cerebrovascular diseases (CVD) including stroke. Very few number of studies have been published in the context of the association between Interleukin-1α(IL-1α), CD14 cell surface glycoprotein (CD14), Galectin-2-encoding gene (LGALS2)and proteasome subunit type 6 (PSMA6) gene polymorphisms with susceptibility to ischemic stroke (IS).

OBJECTIVE

The present meta-analysis aimed to provide a comprehensive account of the association between IL-1α (-C889T and -C511T), CD14 (-C159T), LGALS2 (-C3279T) and PSMA6 (-C8G) gene polymorphisms and susceptibility to IS.

METHODS

A literature search for eligible genetic studies published before August 31, 2015 was conducted in the PubMed, Medline, EMBASE, OVID, and Google Scholar databases. Fixed or random effects models were used to estimate the Pooled Odds ratio (OR) and 95% confidence interval (CI) using RevMan 5.3 software.

RESULTS

Total 21 studies were included in our meta-analysis. No significant association was observed between IL-1α (-C889T) [OR = 1.18, 95% CI: 0.67-2.08, P = 0.58], IL-1α (-C511T) [OR = 0.95, 95% CI: 0.66-1.37, P = 0.77], LGALS2(-C2379T) [OR = 0.29, 95% CI: 0.02-4.26, P = 0.37] and CD14 (-C260T) [OR = 0.93, 95% CI: 0.77-1.11, P = 0. 42] gene polymorphisms and risk of IS. However, protective level of association was observed between PSMA6 (-C8G) gene polymorphism and susceptibility to IS under the recessive model [OR = 0.25, 95% CI: 0.08-0.72, P = 0.01].

CONCLUSION

Our meta-analysis shows that IL-1α (-C889T and -C511T), CD14 (-C159T), LGALS2 (-C3279T) and gene polymorphisms are not significantly associated with the risk of IS while PSMA6 (-C8G) gene polymorphism may play a protective role with the susceptibility of IS. Further prospective large epidemiological studies are needed to confirm these findings in different populations.

Association between interleukin-6 (G174C and C572G) promoter gene polymorphisms and risk of ischemic stroke in North Indian population: a case-control study

BACKGROUND

Polymorphisms of G174C and C572G in the interleukin-6 (IL-6) promoter gene can affect both transcription and secretion of IL-6 and may be involved in inflammation related to and pathogenesis of ischemic stroke (IS). Whether these IL-6 gene polymorphisms are risk factors for IS or not, remains controversial.

OBJECTIVE

The aim of this study was to determine the association between IL-6 G174C and C572G gene polymorphisms and susceptibility to ischemic stroke in North Indian Population.

METHODS

Two hundred and fifty IS patients and 250 age- and sex-matched controls were studied. Genotyping was performed using SNaPshot method. Stroke was classified using Trial of Org 10172 in acute stroke treatment classification. Conditional logistic regression analysis was used to calculate the strength of association between IL-6 (G174C and C572G) polymorphisms and risk of IS.

RESULTS

Hypertension, diabetes, dyslipidemia, alcohol, smoking, family history of stroke, sedentary life style and low socioeconomic status were found to be associated with the risk of IS. Conditional logistic regression analysis showed a significant association of IL-6 G174C with the risk of IS under dominant model (OR, 1.61; 95%CI, 1.0-2.4; P value 0.02) and allelic model (OR, 1.5; 95%CI, 1.0-2.1; P value 0.02). For IL-6 C572G, multivariate adjusted analysis showed a significant association with the risk of IS under dominant model for overall IS (OR, 1.81; 95%CI, 1.04-3.15; P value 0.03) and small vessel disease subtype of IS (OR, 2.8; 95%CI, 1.3-6.0; P value 0.006).

CONCLUSION

Our results suggest that IL-6 (G174C) polymorphism is significantly associated with the risk of IS in North Indian population. However, IL-6 (C572G) polymorphism is found significantly associated with the risk of IS after adjusting the demographic and risk factors variables. Prospective studies with large sample size are required for independent validation. Our findings could be helpful in identifying individuals at increased risk for developing IS.

Association between Tumor Necrosis Factor-α (-238G/A and -308G/A) Gene Polymorphisms and Risk of Ischemic Stroke: A Meta-Analysis

Tumor necrosis factor-α (TNF-α) is a proinflammatory pleiotropic cytokine which may contribute to the initiation and progression of ischemic stroke (IS). Thus far, numerous studies have been performed to examine the association between -238G/A (rs361525) and -308G/A (rs1800629) polymorphisms in the promoter regions of the TNF-α gene and susceptibility to IS, but results are still conflicting. The aim of this meta-analysis is to provide a relatively comprehensive account of the association between TNF-α -238G/A and -308G/A gene polymorphisms and susceptibility to IS. A literature search for eligible candidate gene studies published before April 20, 2015, was conducted in the PubMed, Medline, EMBASE and Google Scholar databases. The following combinations of main keywords were used: ('Tumor Necrosis Factor-Alpha' or 'TNF-α') and ('ischemic stroke' or 'cerebral infarction' or 'IS') and ('genetic polymorphism' or 'single nucleotide polymorphisms' or 'SNP'). Fixed- or random-effect models were used to estimate the pooled odds ratio (OR) and 95% confidence interval (CI). Meta-analysis was carried out by using RevMan 5.3 software. For TNF-α -238G/A gene polymorphism, 7 case-control studies with a total of 1,846 IS patients and 1,905 controls showed a significant association with susceptibility to IS under a dominant model (AA + GA vs. GG; OR, 1.40; 95% CI, 1.11-1.76; p value 0.004). For TNF-α -308G/A gene polymorphism, 16 case-control studies with a total of 5,651 IS patients and 5,792 controls showed a significant protective association with susceptibility to IS under a dominant model (AA + GA vs. GG; OR, 0.78, 95% CI, 0.63-0.97; p value 0.03). Our meta-analysis shows that TNF-α -238G/A gene polymorphism is more likely to be associated with the risk of IS in Caucasian populations as compared to Asian populations. However, TNF-α -308G/A gene polymorphism is more likely to be protective against IS in Asian populations as compared to Caucasian populations. Further large, well-designed prospective epidemiological studies are needed to confirm these findings.

Association of transforming growth factor-β1 gene C509T, G800A and T869C polymorphisms with intracerebral hemorrhage in North Indian Population: a case-control study

Transforming growth factor-β1 (TGF-β1) is a multifunctional pro-inflammatory cytokine involved in inflammation and pathogenesis of cerebrovascular disease. As per our knowledge, there is no published study investigating the association between variations within the TGF-β1 gene polymorphisms and risk of intracerebral hemorrhage (ICH). The aim of this study was to investigate the association of the TGF-β1 gene (C509T, G800A and T869C) polymorphisms, and their haplotypes with the risk of ICH in North Indian population. 100 ICH patients and 100 age- and sex-matched controls were studied. Genotyping was performed using SNaPshot method. Conditional logistic regression analysis was used to calculate the strength of association between TGF-β1 gene polymorphisms and risk of ICH. Hypertension, diabetes, dyslipidemia, low socioeconomic status, smoking, physical activity were found to be associated with the risk of ICH. The distribution of C509T, G800A and T869C genotypes was consistent with Hardy-Weinberg Equilibrium (HWE) in the ICH and control group. Adjusted conditional logistic regression analysis showed an independent association of TGF-β1 G800A (OR 9.07; 95% CI 2.3-35.6; P = 0.002) and T869C (OR 5.1; 95 % CI 1.9-13.2; P = 0.001) with the risk of ICH under dominant model. Haplotype analysis showed that C509-G800-C869 and C509-A800-C869 haplotypes were significantly associated with the increased risk of ICH. C509T and T869C were in strong linkage disequilibrium (D' = 0.53, r(2) = 0.23). Our results suggest that TGF-β1 (G800A, T869C) gene polymorphisms and their haplotypes are significantly associated with the risk of ICH in North Indian population. Further prospective studies with large sample size are required for independent validation. Our findings could be helpful in identifying individuals at increased risk for developing ICH.

Tumor necrosis factor-alpha (- 308G/A, + 488G/A, - 857C/T and -1031 T/C) gene polymorphisms and risk of ischemic stroke in north Indian population: A hospital based case-control study

Background

Genetic factors may play a role in the susceptibility of Ischemic stroke (IS). Previous studies have shown that Tumour necrosis factor-α (TNF-α) gene polymorphisms were associated with the risk of IS in multiple ethnicities. The present case–control study tested the hypothesis that genetic polymorphisms of the TNF-α gene may affect the risk of IS in North Indian population. We investigated the association of four single nucleotide polymorphisms (− 308G/A, + 488G/A, − 857C/T and -1031 T/C) within TNF-α gene promoter and their haplotypes with the risk of IS.

Methods

IS was classified using the Trial of Org 10,172 in Acute Stroke Treatment (TOAST) classification. Genotyping was performed for 250 IS patients and 250 age- and sex-matched IS free controls by using SNaPshot technique. Multivariate logistic regression was used to control the confounding effects of demographic and risk factor variables. Haplotype analyses were done by using PHASE software and Linkage disequilibrium (LD) analyses were done by using Haploview version 4.2 software.

Results

An independent association between TNF-α + 488G/A (OR = 2.59; 95%CI 1.46 to 4.60; p = 0.001) and -857C/T (OR = 1.77; 95%CI 1.01 to 3.11; p < 0.04) and risk of IS was observed under dominant model. However, no significant association between -308G/A and -1031 T/C gene polymorphisms and risk of IS was observed. Haplotype analysis showed that A308-G488-C857-T1031 haplotypes were significantly associated with the increased risk of IS [OR = 1.66; 95%CI 1.02 to 2.71; p = 0.003]. Strong linkage disequilibrium (LD) was observed for + 488G/A and -857C/T (D’ = 0.41, r² = 0.004).

Conclusions

Two SNPs (+ 488G/A and -857C/T) of TNF-α gene and their haplotypes are significantly associated with the risk of IS in the population enrolled from North India. Our findings indicate that polymorphisms and haplotypes of TNF-α gene may be used as a genetic marker for identifying individuals at increased risk for developing IS.

The association between three promoter polymorphisms of IL-1 and stroke: a meta-analysis

AIM

The association between Interleukin-1 (IL-1) gene polymorphism and stroke remains controversial. The present study was designed to clarify this relationship through a pooled analysis of the numerous epidemiological studies focusing on this association.

METHODS

Published data addressing the association between polymorphism of the IL-1 gene and stroke were selected from electronic databases. A total of 21 studies from 19 publications including 5280 stroke patients and 5699 controls were included in this meta-analysis which detect whether IL-1α-889C/T, IL-1β-511C/T and IL-1 RN polymorphism were associated with stroke susceptibility.

RESULT

The combined results of overall analysis revealed that there was a significant association between IL-1α-889C/T polymorphism and stroke (allele model: OR = 1.39, 95% CI = 1.14-1.68, P < 0.001; recessive model: OR = 1.56, 95% CI = 1.27-1.90, P < 0.001; dominant model: OR = 1.45, 95% CI = 1.13-1.87, P = 0.004; additive model: OR = 1.70, 95% CI = 1.37-2.10, P < 0.001). On a subgroup analysis by ethnicity of study population, significant association was found in Asians (allele model: OR = 1.25 95% CI = 1.12-1.39, P < 0.001; recessive model: OR = 1.36, 95% CI = 1.09-1.69, P = 0.007; dominant model: OR = 1.29, 95% CI = 1.12-1.48, P < 0.001; additive model: OR = 1.42, 95% CI = 1.13-1.80, P = 0.003). There are no associations of IL-1β-511C/T and IL-RN polymorphisms on stroke risk were identified.

CONCLUSION

In conclusion, our results suggested that IL-1α-889C/T polymorphism is associated with stroke risk, especially in Asians. However, no associations of IL-1β-511C/T and IL-RN polymorphisms on stroke risk in overall analysis or subgroup analysis.

Investigation on the IL-18 -607A/C and -137C/G on the susceptibility of ischemic stroke

OBJECTIVE

We conducted a case-control study with 322 cases and 322 controls to assess the role of the two common SNPs in the promoter of IL-18 gene.

METHODS

Polymerase chain reaction restriction fragment length of polymorphism (PCR-RFLP) was taken to genotype -607A/C and -137C/G in the promoter of the IL-18 gene.

RESULTS

By comparing cases and control subjects, we found that IS cases were more likely to have higher BMI, higher proportion of hypertension, and have higher proportion of smokers and drinkers. We found that IL-18 -607CC genotype (OR=1.70, 95% CI=1.03-2.81) and C allele (OR=1.26, 95% CI=1.01-1.58) were significantly more frequent in IS patients when compared with AA genotype. We did not find significant association between IL-18 -607A/C gene polymorphism and BMI, hypertension, smoking and drinking on the risk of IS.

CONCLUSION

Our study suggests that polymorphisms in IL-18 -607A/C can influence the development of IS, and this gene polymorphism is associated with risk of IS in a Chinese population.

Association between Interleukin-6 (G174C and G572C) promoter gene polymorphisms and risk of ischaemic stroke: A meta-analysis

BACKGROUND

Interleukin-6 (IL-6), as one of the most typical pro-inflammatory and immunoregulatory cytokines, is believed to be associated with the genesis and maintenance of inflammatory response. Genetic association studies (GAS) that have investigated the association between Interleukin 6 (G174C and G572C) promoter gene polymorphisms and susceptibility to ischemic stroke (IS) which have produced contradictory and unconvincing results.

PURPOSE

The aim of this meta-analysis is to provide a relatively comprehensive account of the association of IL-6 (G174C and G572C) polymorphisms with susceptibility to IS.

METHODS

A literature search was conducted using electronic database PubMed, Medline, and Trip database for all case-control studies investigating for association of IL-6 genetic polymorphisms with ischemic stroke published till August 30, 2014. The following combinations of main keywords were used: ('Interleukin-6' or 'IL-6') and ('ischaemic stroke or 'cerebral infarction' or 'IS') and ('genetic polymorphism' or 'single nucleotide polymorphisms' or 'SNP'). Pooled Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for IL-6 gene-disease association. Meta-analysis was carried out using Revman 5.3 software.

RESULTS

16 case-control studies involving a total of 3,317 IS patients and 3,432 healthy controls for G174C polymorphism and 3 case-control studies with a total of 2,001 IS patients and 2,027 healthy controls for G572C IL-6 gene polymorphisms were included in a meta-analysis. For IL-6 G174C gene polymorphisms, no significant association was observed under dominant [GC + CC vs. GG: OR = 1.01, 95% CI: 0.77-1.34, P = 0. 92], recessive [CC vs. GG + GC: OR = 0.82, 95% CI: 0.40-1.70, P = 0. 59] and allelic model [C vs. G Allele: OR = 0.99, 95% CI: 0.74-1.31, P = 0. 93]. For IL-6 G572C, no significant association was observed under dominant [CC vs. GG + GC: OR = 0.99, 95% CI: 0.57-1.71, P = 0. 97], recessive [CC vs. GG + GC: OR = 0.93, 95% CI: 0.60-1.45, P = 0. 75] and allelic model [C vs. G Allele: OR = 0.95, 95% CI: 0.66-1.36, P = 0. 76].

CONCLUSION

This meta-analysis shows that IL-6 (G174C) and IL-6 (G572C) gene polymorphisms may not be associated with an increased susceptibility to IS. Further studies are required for confirmatory results.

Interleukin-6 gene-174 G/C promoter polymorphism and its association with clinical profile of patients with multiple myeloma

AIM

In multiple myeloma (MM), the growth and survival of myeloma cells is controlled by interleukin-6 (IL-6), the plasma levels of which is controlled by a guanine/cytosine substitution occurring in position -174 of IL-6 gene promoter region. We studied the occurrence of IL-6-174 G/C polymorphism in patients of MM and correlated the presence of genotypes with serum IL-6 levels and tumor staging.

METHODS

One hundred three patients with MM and 117 age- and sex-matched healthy controls were staged by International Staging System. IL-6 genotypes were evaluated by polymerase chain reaction and restriction enzyme analysis. Serum levels of IL-6 were assessed by enzyme-linked immunosorbent assay.

RESULTS

Frequency of GG, GC and CC genotypes did not differ significantly between cases (GG 52%, GC 40%, CC 9%) and controls. The median serum level of IL-6 was significantly higher among the GC genotype versus other genotypes (24 ng/mL, P = 0.007) as compared with the GG versus other genotypes (12 ng/mL, P = 0.001). GC was associated more with stage 3 disease (27%) than was GG (11%) or CC (22% P = 0.001).

CONCLUSIONS

At position 174 of the IL-6 promoter, patients with GC genotype had higher serum levels of IL-6 and presented with more severe disease compared with patients with GG or CC genotype.

PSMA6 (rs2277460, rs1048990), PSMC6 (rs2295826, rs2295827) and PSMA3 (rs2348071) genetic diversity in Latvians, Lithuanians and Taiwanese

PSMA6 (rs2277460, rs1048990), PSMC6 (rs2295826, rs2295827) and PSMA3 (rs2348071) genetic diversity was investigated in 1438 unrelated subjects from Latvia, Lithuania and Taiwan. In general, polymorphism of each individual locus showed tendencies similar to determined previously in HapMap populations. Main differences concern Taiwanese and include presence of rs2277460 rare allele A not found before in Asians and absence of rs2295827 rare alleles homozygotes TT observed in all other human populations. Observed patterns of SNPs and haplotype diversity were compatible with expectation of neutral model of evolution. Linkage disequilibrium between the rs2295826 and rs2295827 was detected to be complete in Latvians and Lithuanians (D´ = 1; r² = 1) and slightly disrupted in Taiwanese (D´ = 0.978; r² = 0.901).

Population differentiation (F_ST statistics) was estimated from pairwise population comparisons of loci variability, five locus haplotypes and PSMA6 and PSMC6 two locus haplotypes. Latvians were significantly different from all Asians at each of 5 SNPs and from Lithuanians at the rs1048990 and PSMC6 loci. Lithuanian and Asian populations exhibited similarities at the PSMC6 loci and were different at the PSMA6 and PSMA3 SNPs. Considering five locus haplotypes all European populations were significantly different from Asian; Lithuanian population was different from both Latvian and CEU.

Allele specific patterns of transcription factor binding sites and splicing signals were predicted in silico and addressed to eventual functionality of nucleotide substitutions and their potential to be involved in human genome evolution and geographical adaptation. Current study represents a novel step toward a systematic analysis of the proteasomal gene genetic diversity in human populations.

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SNPs in PSMA6, PSMC6 and PSMA3 differentiate Latvian and Taiwanese populations.

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rs2277460, rs1048990 and rs2348071 differentiate Lithuanians and Taiwanese.

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Lithuanians and Taiwanese are similar in rs2295826, rs2295827 diversity.

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rs1048990, rs2295826 and rs2295827 differentiate Latvians and Lithuanians.

Influence of the β-fibrinogen-455G/A polymorphism on development of ischemic stroke and coronary heart disease

BACKGROUND

Ischemic stroke (IS) and coronary heart disease (CHD) are two vascular disorders that are a common cause of death worldwide. Several studies have assessed the association of the β-fibrinogen-455G/A (FGB-455G/A) polymorphism and risk of IS and CHD, but the results are still inconsistent. Our study aimed to investigate whether the FGB-455G/A polymorphism was associated with susceptibility to IS and CHD by using meta-analysis.

METHODS

Relevant studies were identified from PubMed, Embase and four Chinese database up to July 2013.Data were analyzed and processed by Stata 11.2. A pooled OR with 95% CI was calculated to estimate the strength of the genetic association. Cumulative meta-analysis was performed to assess the tendency of pooled OR over time.

RESULTS

45 studies based on a total of 7238 cases and 7395 controls were included in our meta-analysis. The results indicated that the FGB-455G/A polymorphism is associated with the risk of IS when compared with the dominant model (OR=1.518, 95%CI=1.279-1.802 for AA+GA vs. GG). In the subgroup analysis by ethnicity, significantly elevated risks were associated with the A allele in Asians (OR=1.700, 95%CI=1.417-2.040), but not in Caucasians (OR=0.942, 95%CI=0.813-1.091). Both the hypertension and non-hypertension subgroups reached significant results, but no significance was found when stratified according to sex or subtype of IS. Results indicate that the FGB-455G/A polymorphism is associated with CHD (OR=1.802, 95%CI=1.445-2.246).

CONCLUSION

Our meta-analysis suggests that the FGB-455G/A polymorphism contributes to susceptibility to IS and CHD.

[Association of T174M polymorphism of the angiotensinogen gene with the higher risk of cerebral stroke in women]

AIM

To study the association of M235T (rs699) and T174M (rs4762) polymorphisms of the angiotensinogen (AGT) gene with the risk of cerebral stroke (CS) in the Russians of the Central Chernozem Region.

MATERIALS AND METHODS

A total of 638 DNA samples obtained from 353 patients with CS and 285 sex- and age-matched healthy individuals were examined. The polymorphisms were genotyped by polymerase chain reaction (T174M) and TaqMan allelic discrimination (M235T) assays.

RESULTS

Heterozygous AGT 174TM genotype carriers were found to be at a higher risk for CS (odd ratio (OR) = 1.52; 95% confidence interval (CI), 1.08-2.15; p = 0.02). A gender-stratified analysis showed that the mutant 174M allele (OR = 1.86; 95% CI, 1.14-3.03, p = 0.01) and variant 174TM and 174MM genotypes (OR = 1.86; 95% CI, 1.09-3.20; p = 0.02) were associated with the higher risk of cerebral stroke in women.

CONCLUSION

The association of AGT T174M polymorphism with the risk of CS was first found; but the higher risk of the disease in the carriers of variant alleles and genotypes was observed in the women only.

Influence of interleukin-6 gene -174G>C polymorphism on development of atherosclerosis: a meta-analysis of 50 studies involving 33,514 subjects

Increasing epidemiological studies have focused on the associations between interleukin-6 (IL-6) gene -174G>C polymorphism and atherosclerotic diseases, but the results are still controversial. This meta-analysis was designed to identify whether this association exists. PubMed, Embase, Web of Science, Cochrane database, Clinicaltrials.gov and Current Controlled Trials, Chinese Clinical Trial Registry, CBMdisc, CNKI and Google Scholar were searched to get the genetic association studies. The crude odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were used to estimate the association between the IL-6 gene -174G>C polymorphism and atherosclerosis ( AS ) risk. The subgroup analyses were made on the following: ethnicity, atherosclerotic diseases and source of controls. Finally, 50 studies (15,029 cases and 18,485 controls) were included in this meta-analysis. Overall, no significant association was found between the IL-6 gene -174G>C polymorphism and AS risk (for C allele vs. G allele: OR=1.02, 95% CI=0.94-1.11, p=0.64; for C/C vs. G/G: OR=1.01, 95% CI=0.85-1.21, p=0.88; for C/C vs. C/G+G/G: OR=0.97, 95% CI=0.84-1.12, p=0.68; for C/C+C/G vs. G/G: OR=1.07, 95% CI=0.97-1.17, p=0.18). In the subgroup analyses, significant associations were found between the IL-6 gene -174G>C polymorphism and AS in non-Caucasian group (for CC+CG vs. GG: OR=1.22, 95% CI=1.06-1.41, p=0.005), other atherosclerotic diseases group (for C allele vs. G allele: OR =0.75, 95% CI=0.61-0.93, p=0.008; for C/C vs. G/G: OR=0.56, 95% CI=0.38-0.81, p=0.002; for C/C vs. C/G+G/G: OR=0.60, 95% CI=0.45-0.79, p=0.0004) and population-based group (for C allele vs. G allele: OR=1.09, 95% CI=1.00-1.18, p=0.04; for CC+CG vs. GG: OR=1.15, 95% CI=1.04-1.27, p=0.005). In summary, the present meta-analysis suggests that the IL-6 gene -174G C polymorphism is associated with the susceptibility to AS. However, due to the high heterogeneity in the meta-analysis, the results should be interpreted with caution.

AGT M235T polymorphisms and ischemic stroke risk: a meta-analysis

Recently, the association between AGT M235T polymorphism and ischemic stroke (IS) has attracted widespread attention, and many investigations have been performed. However, the results were inconsistent. Therefore, we performed a meta-analysis to further evaluate the association between M235T and IS. All of the relevant studies were identified from PubMed, EMBASE, Chinese National Knowledge Infrastructure database (CNKI), Chinese Biological Medical Literature database (CBM), Chinese Wanfang and Chongqing VIP database up to January 2013. Statistical analyses were conducted with STATA software version 11.1. Odds ratios with 95% confidence interval were applied to evaluate the strength of the association. We performed the cumulative meta-analysis to assess the tendency of pooled OR over time. Heterogeneity was evaluated by Q-test and the I(2) statistic. The funnel plots and Egger's regression test were used to assess the publication bias. A significant association between AGT M235T polymorphism and IS was found under the dominant model (OR=1.368, 95% CI=1.070-1.749), recessive model (OR=1.66, 95% CI=1.310-2.103), over-dominant model (OR=1.285, 95% CI=1.085-1.523), co-dominant model (OR=1.574, 95% CI=1.276-1.942) and allele model (OR=1.447, 95% CI=1.207-1.735). Besides the Caucasian and the population-based controls, significant association could be found in the subgroup analysis of Asian and hospital-based controls. Results from cumulative analysis showed a tendency of significant association of this polymorphism with IS. However, the opposite trend was observed among Caucasians. Results from our meta-analysis indicated that the AGT M235T polymorphism might be a risk factor for IS among Asians, but not for Caucasians. More studies are required to further confirm our findings.

Endothelial NO synthase gene polymorphisms and risk of ischemic stroke in Asian population: a meta-analysis

Background

The association between polymorphism 4b/a, T-786C and G894T in endothelial NO synthase gene (eNOS) and ischemic stroke (IS) remains controversial in Asian. A meta-analysis was performed to better clarify the association between eNOS gene and IS risk.

Methods

Based on the search of PubMed, Web of Science (ISI), CNKI (National Knowledge Infrastructure), Wan Fang Med Online and CBM (Chinese Biology Medical Literature Database) databases, all eligible case-control or cohort studies were identified. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) from fixed and random effect models were calculated. Heterogeneity among studies was evaluated using the I². Meta-regression was used to explore the potential sources of between-study heterogeneity. Begg's test was used to estimate publication bias.

Results

Our study included 27 articles, contained 28 independent case–control studies, involved a total of 3,742 cases and 3,691 controls about 4b/a, 1,800 cases and 1,751 controls about T-786C and 2,747 cases and 2,872 controls about G894T. A significant association of 4a allele with increased risk of IS was found in dominant (FEM: OR = 1.498, 95% CI = 1.329–1.689), recessive (FEM: OR = 2.132, 95% CI = 1.383–3.286) and codominant (REM: OR = 1.456, 95% CI = 1.235–1.716) models. For T-786C and G894T, there were significant associations with dominant and codominant genetic models, but not with recessive genetic model.

Conclusions

The meta-analysis indicated that eNOS gene 4b/a, T-786C, G894T polymorphism might be associated with IS.

Detailed analysis of gene polymorphisms associated with ischemic stroke in South Asians

The burden of stroke is disproportionately high in the South Asian subcontinent with South Asian ethnicity conferring a greater risk of ischemic stroke than European ancestry regardless of country inhabited. While genes associated with stroke in European populations have been investigated, they remain largely unknown in South Asians. We conducted a comprehensive meta-analysis of known genetic polymorphisms associated with South Asian ischemic stroke, and compared effect size of the MTHFR C677T-stroke association with effect sizes predicted from homocysteine-stroke association. Electronic databases were searched up to August 2012 for published case control studies investigating genetic polymorphisms associated with ischemic stroke in South Asians. Pooled odds ratios (OR) for each gene-disease association were calculated using a random-effects model. We identified 26 studies (approximately 2529 stroke cases and 2881 controls) interrogating 33 independent genetic polymorphisms in 22 genes. Ten studies described MTHFR C677T (108 with TT genotype and 2018 with CC genotype) -homocysteine relationship and six studies (735 stroke cases and 713 controls) described homocysteine-ischemic stroke relationship. Risk association ORs were calculated for ACE I/D (OR 5.00; 95% CI, 1.17–21.37; p = 0.03), PDE4D SNP 83 (OR 2.20; 95% CI 1.21–3.99; p = 0.01), PDE4D SNP 32 (OR 1.57; 95% CI 1.01–2.45, p = 0.045) and IL10 G1082A (OR 1.44; 95% CI, 1.09–1.91, p = 0.01). Significant association was observed between elevated plasma homocysteine levels and MTHFR/677 TT genotypes in healthy South Asians (Mean difference (ΔX) 5.18 µmol/L; 95% CI 2.03–8.34: p = 0.001). Our results demonstrate that the genetic etiology of ischemic stroke in South Asians is broadly similar to the risk conferred in Europeans, although the dataset is considerably smaller and warrants the same clinical considerations for risk profiling.

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.

Association of inflammatory response gene polymorphism with atherothrombotic stroke in Northern Han Chinese

Atherosclerosis is an important pathophysiological basis of atherothrombotic stroke (ATS), and inflammation plays a significant role in atherosclerosis formation. In this study, single-nucleotide polymorphisms (SNPs) in three key inflammation-related genes, 5-lipoxygenase activating protein (ALOX5AP), phosphodiesterase 4D (PDE4D), and interleukin-1α (IL-1α), were investigated to determine their association with ATS in Northern Han Chinese. Six-hundred and eighty-two ATS patients and 598 unrelated controls were recruited. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism and matrix-assisted laser desorption ionization time-of-flight mass spectrometry primer extension. The genotype and allele frequencies of each SNP were statistically analyzed. Risk of ATS was found for the ALOX5AP SG13S114A/T AA genotype (P = 0.040) and A allele (P = 0.033), PDE4D SNP83C/T TT genotype (P = 0.010) and T allele (P = 0.008) and SNP219A/G GG genotype (P = 0.025) and G allele (P = 0.022), and the IL-1α-889C/T T allele (P = 0.035). The differences still remained significant after adjustment. The ALOX5AP HapA haplotype was not correlated with ATS (P = 0.834), but GCGA represented an at-risk haplotype (P = 0.008). Furthermore, the PDE4D AA haplotype at SNP219-220 might be an at-risk haplotype (P = 0.013), while GA might be a protective haplotype (P = 0.005). The ALOX5AP (SG13S114A/T), PDE4D (SNP83C/T, 219A/G), and IL-1α (-889C/T) SNPs were associated with an increased risk of ATS in Northern Han Chinese.