Polymorphisms of -174G>C and -572G>C in the interleukin 6 (IL-6) gene and coronary heart disease risk: a meta-analysis of 27 research studies

A Set of Possible Markers for Monitoring Heart Failure and Cognitive Impairment Associated: A Review of Literature from the Past 5 Years

BACKGROUND

Heart failure is an epidemiologically relevant disease because of the aging population and widespread lifestyles that promote it. In addition to the acute event, it is possible for the disease to become chronic with periodic flare-ups. It is essential to study pathology from a diagnostic and prognostic point of view and to identify parameters for effective monitoring. In addition, heart failure is associated with multiple comorbidities, including cognitive impairment, which is monitored clinically but not through specific biomarkers in these patients. The purpose of this review is to gather the most recent scientific evidence on a few possible biomarkers previously identified for monitoring heart failure and associated cognitive impairment.

METHODS

We surveyed studies inherent to a set of previously identified markers, evaluating English-language articles from the past five years conducted in adult heart failure patient populations. We used the databases PubMed, Web of Sciences, and Cochrane Library for search studies, and we considered articles published in journals with an impact factor greater than five in the publication year.

RESULTS

Among the biomarkers evaluated, a concordant indication for serial measurements for heart failure monitoring emerged only for interleukin-6. For the other markers, there is still little evidence available, which is interesting but sometimes conflicting. Interesting studies have also emerged for biomarkers of cognitive decline assessed in patients with heart failure, confirming the hypotheses of the increasingly studied heart-brain correlation.

CONCLUSION

Certainly, further studies in large populations are needed to identify effective biomarkers for monitoring heart failure and associated cognitive impairment.

Association Between Interleukin-6 Gene Polymorphism and Severity of Coronary Artery Disease in Patients with Diabetes

Introduction

Previous studies have identified diabetes as a risk factor for coronary heart disease. This study determined the correlation between the IL-6 gene -572 G/C polymorphism and the incidence and severity of coronary heart disease in patients with diabetes.

Methods

One hundred four patients with diabetes who were admitted to our hospital from January 2019 to December 2020 were retrospectively enrolled in the current study. These patients were divided into a diabetes only group (group A, 27 patients) and a diabetes complicated by coronary heart disease group (group B, 77 patients). Seventy patients in the latter group were further divided into low, medium, and high Syntax score groups based on coronary angiography results. A correlation analysis between IL-6, blood lipids, and the IL-6 -572 G/C gene levels was performed.

Results

The serum IL-6 level in patients with the IL-6-572G/C-GG genotype was higher than patients with the GC and CC genotypes. In patients with diabetes, the presence of the IL-6-572G/C-GG and GC genotypes was associated with a significantly increased risk of developing coronary heart disease. Patients with the IL-6-572G/C-GG genotype and diabetes were shown to have more severe coronary artery lesions compared to patients with the CC genotype. Moreover, the G allele of the IL-6-572G/C gene was linked to a higher risk of coronary heart disease and more severe coronary artery lesions in patients with diabetes compared to the C allele.

Conclusion

The IL-6-572G/C gene polymorphism is associated with the incidence and severity of coronary heart disease in patients with diabetes.

Gene polymorphism among hypertensive patients with coronary artery disease

The obstruction of the coronary arteries causes Coronary Artery Disease (CAD). It has been reported that interleukin-6 gene is related to the development of cardiovascular diseases such as atherosclerosis and coronary artery disease. This was due to the large variability and short half-life of interleukin 6 (IL-6). There are few studies on the link between interleukin 6 and CAD on the patients with hypertension. Therefore, goal of this study was to see if there is a link between IL-6 gene polymorphisms and coronary artery disease with hypertension patients. The polymorphisms were carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The data was determined for statistical significance using chi-square analysis. A significant difference was found in the GG genotype of IL-6 -174, which was more frequent in cases of CAD (48.67 %) than in controls (8%) and 95% CI was 0.473455 - 0.500326; P<0.010620511. The GG genotype of IL-6-572C/G polymorphism was more frequent in cases of CAD (42.6%) compared with controls (8%) and 95% CI 0.386724 - 0.480945; P<0.017939631). likewise, significant association of variant allele G with CAD patients was reported. Hypertension was significantly higher among patients as compared to controls (P<0.022847535). Our findings indicated that both gene polymorphisms may be associated with development of CAD.

Association of IL-6 promoter polymorphism hotspots (- 174G/C and - 572G/C) with cardiovascular disease risk factors

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death globally, despite the recent advancements in clinical research. Early diagnosis of CVD and prevention of future complications are important for the management of CVD. In the present study, we determined the genotypic linkage of interleukin-6 (IL-6) promoters with the clinical, biochemical, and inflammatory markers of CVD in the Saudi population.

MATERIALS AND METHODS

The study consisted of 89 patients (male and female) with CVD who were admitted at the King Abdulaziz university hospital, Jeddah, Saudi Arabia. The biochemical parameters were evaluated using an automated chemistry analyzer, and inflammatory markers were measured using specific enzyme-linked immunosorbent assay (ELISA) kits. For genotypic analysis, Sanger sequencing was performed. We observed a statistically significant association (p < 0.05) between GG (66.29%), GC (30.34%), and CC (3.37%) genotypes at the - 174G/C (rs1800795) hotspot and neopterin levels. However, the genotypes at the - 572G/C (rs1800796) hotspot did not show any association with age, gender, obesity, diabetes, hypertension, dyslipidemia, smoking, and coronary artery status. In addition, no significant association was observed with biochemical and inflammatory markers, namely fasting blood sugar, glycated hemoglobin A1c, creatinine, total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, IL-6, and C-reactive protein. The comparison between different possible genotypic groups and CVD risk factors showed a statistically significant (p < 0.05) association between the male gender and HDL with GG, rs1800795 group vs. GC, rs1800796 group. Similarly, neopterin level was also found to be significantly (p < 0.05) associated with the genotypes GC, rs1800795, and GG, rs1800796. Additionally, the male gender (p < 0.01), age (p < 0.05), serum creatinine (p < 0.001), and neopterin (p < 0.05) were found to be significantly associated with GG, rs1800795 + GG, rs1800796, GC, rs1800795 + GC, and rs1800796 GC.

CONCLUSION

The direct association of neopterin level with IL-6 promoter polymorphism at - 174G/C (rs1800795) hotspot indicated the role of inflammation in CVD pathogenesis in the Saudi population.

Association of interleukin 6 -174 G/C polymorphism with coronary artery disease and circulating IL-6 levels: a systematic review and meta-analysis

INTRODUCTION

Circulating IL-6 levels and at least one polymorphic form of IL6 gene (IL6 -174 G/C, rs1800795) have been shown to be independently associated with coronary artery disease (CAD) by several investigators. Despite more than 12 published meta-analyses on this subject, association of -174 G/C with CAD, especially amongst distinct ancestral population groups remain unclear. We, therefore, conducted a systematic review and an updated meta-analysis to comprehensively ascertain the association of IL6 -174 G/C with CAD and circulating IL-6 levels.

MATERIALS AND METHODS

Relevant case-control/cohort studies investigating association of -174 G/C with CAD and circulating IL-6 levels were identified following a comprehensive online search. Association status for CAD was determined for the pooled sample, as well as separately for major ancestral subgroups. Association status for circulating IL-6 levels was assessed for the pooled sample, as well as separately for CAD cases and CAD free controls. Study-level odds ratios (OR) and 95% confidence intervals (CI) were pooled using random/fixed-effects model.

RESULTS

Quantitative synthesis for the CAD endpoint was performed using 55 separate qualifying studies with a collective sample size of 51,213 (19,160 cases/32,053 controls). Pooled association of -174 G/C with CAD was found to be statistically significant through dominant (OR 1.15; 95% CI 1.05-1.25, p = 0.002) as well as allelic genetic model comparisons (OR 1.13, 95% CI 1.06-1.21, p = 0.0003). This effect was largely driven by Asian and Asian Indian ancestral subgroups, which also showed significant association with CAD in both genetic model comparisons (OR range 1.29-1.53, p value range ≤ 0.02). Other ancestral subgroups failed to show any meaningful association. Circulating IL-6 levels were found to be significantly higher amongst the 'C' allele carriers in the pooled sample (Standard mean difference, SMD 0.11, 95% CI 0.01-0.22 pg/ml, p = 0.009) as well as in the CAD free control subgroup (SMD 0.10, 95% CI 0.02-0.17 pg/ml, p = 0.009), though not in the CAD case subgroup (SMD 0.17, 95% CI = - 0.02 to 0.37, p = 0.12).

CONCLUSIONS

The present systematic review and meta-analysis demonstrate an overall association between IL6 -174 G/C polymorphism and CAD, which seems to be mainly driven by Asian and Asian Indian ancestral subgroups. Upregulation of plasma IL-6 levels in the 'C' allele carriers seems to be at least partly responsible for this observed association. This warrants further investigations with large, structured case-control studies especially amongst Asian and Asian Indian ancestral groups.

The effect of polymorphisms (174G> C and 572C> G) on the Interleukin-6 gene in coronary artery disease: a systematic review and meta-analysis

Background

Coronary Artery Disease (CAD) is caused by the blockage of the coronary arteries. it is argued that there has an association between the Interleukin-6 gene and the occurrence of atherosclerosis, coronary artery disease, Due to the short half-life and high variability of Interleukin-6 (IL-6), limited studies have been performed on the association of serum levels of interleukin-6 with coronary artery disease. The aim of this study is to investigate the relationship between IL-6 gene polymorphisms and coronary artery disease.

Methods

This study was conducted as a meta-analysis of selected articles with no lower time limit and upto March 2020. Articles related to the subject were obtained by searching several data sources,such as the SID, IranDoc, Scopus, Embase, Web of Science (ISI), PubMed, Science Direct, and Google Scholar databases. The heterogeneity of the studies was assessed using the I² index in the Comprehensive Meta-Analysis software.

Results

The GG genotype of the IL-6174 G> C polymorphism with a 0.8 odds ratio tended to reduce the risk of CAD by 20%. The odds ratio of CAD in CG and GG genotypes were found to be 1.16 and 1.48 times respectively, indicating the increasing effect of these two genotypes. In the IL-6-572 C>G polymorphism, CG and GG genotypes increased the risk of CAD by 1.21 and 1.27 times respectively, and the CC genotype tended to reduce the risk of CAD by 15%, considering the odds ratio of 0.85.

Conclusion

This study showed a relationship between IL-6174G> C and Interleukin-6 (IL-6) 572 C>G genes and coronary artery disease. Moreover, the protective effects of GG genotype in IL-6 gene 174 G> C and CC genotype in IL-6 gene 572 C>G gene were reported. The study also confirmed that the CG and CC genotypes of the G>C IL-6174 gene have an increasing effect on coronary artery disease. Moreover, CG and GG genotypes in the IL-6 gene 572 C>G increased the risk of developing CAD. It should be noted that the increased risk of developing CAD was limited to meta-analytic studies in reported literatures.

Gene Polymorphisms Increasing the Risk of Intracranial Aneurysms: Interleukin-6 -174G>C and -572G>C (Part II)

Introduction The interleukin-6 (IL-6), a proinflammatory cytokine, supports the adaptive immune response and regulates inflammatory processes. The -174 G>C and -572 G>C promoter polymorphisms of the IL-6 gene take part in the pathogenesis of intracranial aneurysms (IAs) and influence the clinical presentation of subarachnoid hemorrhage. This meta-analysis purposes to evaluate whether and which IL-6 allelic variations are related to a risk of IAs formation. Methods A PRISMA-based literature search was performed on the PubMed/Medline and Web of Science databases. The keywords used were "interleukin-6," "IL-6," "polymorphism," "interleukin-6 genotype," combined with "intracranial aneurysms" and "subarachnoid hemorrhage." Only human case-control studies, with a study (IAs) and a control group, written in English, and published in the last 15 years were selected. A meta-analysis was performed, estimating odds ratios and 95% confidence intervals in fixed- or random-effects models, as applicable. Statistical analysis was conducted with RevMan 5.0 software. Results 9 studies were eligible. No associations were found between -174 G>C polymorphisms and IAs susceptibility. Notable results were reported by the analysis of -572G>C polymorphisms. -572GG/GC/CC genotypes were strongly related to IAs occurrence with a statistical significance of p=0.03, p=0.0009, and p=0.00001, respectively. Conclusion A higher incidence of -572G>C promoter polymorphisms were demonstrated in the IAs group, highlighting the pivotal role of inflammatory genes in the natural history of brain aneurysms. Additional studies are required considering the racial heterogenicity and the need to widen the population sample.

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.

Tumor Necrosis Factor-Alpha and Interleukin-6 Gene Polymorphisms in Iranian Patients with Ischemic Heart Failure

BACKGROUND

Proinflammatory cytokines have been known to be elevated in patients with Chronic Heart Failure (CHF). Given the importance of proinflammatory cytokines in the context of the failing heart, the prevalence of Tumor Necrosis Factor-α (TNF-α), Interleukin (IL)-6 polymorphisms in patients with CHF was studied due to ischemic heart disease.

METHODS

Forty three patients with ischemic heart failure were enrolled in this study and compared with 140 healthy individuals. The allele and genotype frequency of four Single Nucleotide Polymorphisms (SNPs) within the IL-6 (-174, nt565) and TNF-α (-308, -238) genes were determined, using Polymerase Chain Reaction with Sequence-Specific Primers (PCR-SSP) assay.

RESULTS

The frequency of the TNF-α (-238) A/A genotype was significantly higher in patients comparing to controls (p=0.043), while TNF-α G/A genotype at the same position decreased significantly, in comparison with controls (p=0.018). The most frequent haplotype for TNF-α was A/A in the patient group in comparison with controls (p=0.003). There was no significant difference in allele and genotype frequencies of IL-6 at positions -174 and nt565, and TNF-α at position -308.

CONCLUSION

Certain alleles, genotypes, and haplotypes in TNF-α, but not IL-6, gene were overrepresented in patients with ischemic heart failure, which may, in turn, predispose individuals to this disease.

Interactions between vitamin D receptor (VDR) gene and Interleukin-6 gene and environment factors on coronary heart disease risk in a Chinese Han population

AIMS

To investigate the association of several single nucleotide polymorphisms (SNPs) within Interleukin-6 (IL- 6) and vitamin D receptor (VDR) gene, and additional gene- gene and gene- smoking interaction with coronary heart disease (CHD) risk in a Chinese population.

METHODS

Hardy-Weinberg equilibrium (HWE) examination was used by SNPstats (http://bioinfo.iconcologia.net/SNPstats). Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among SNPs and smoking. Stratified analysis for gene- smoking interaction was investigated by logistic regression.

RESULTS

CHD risk was significantly higher in carriers with the C allele of rs1800796 within IL-6 gene than those with GG genotype (GC+ CC versus GG), adjusted OR (95%CI) =1.62 (1.19-2.23); CHD risk was also higher in carriers with the T allele of rs2228570 within VDR gene than those with CC genotype (CT+ TT versus CC), adjusted OR (95%CI) = 1.68 (1.26-2.17). However, we did not find any direct associations of the others SNPs in IL- 6 and VDR gene with CHD risk. We also found a significant interaction between rs1800796 and smoking, the cross-validation consistency of this two- locus model was 10/ 10, and the testing accuracy was 60.11%. Current smokers with rs1800796- GC or CC genotype have the highest CHD risk, compared to never- smokers with rs1800796- GG genotype within IL- 6 gene, OR (95%CI) = 2.57 (1.74 -3.46).

CONCLUSIONS

We found that the C allele of rs1800796 within IL-6 and T allele of rs2228570 within VDR gene, interaction between rs1800796 and smoking were all associated with increased CHD risk.

The effects of IL-1A and IL-6 genes polymorphisms on gene expressions, hormonal and biochemical parameters in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a multifactorial disease characterised by chronic inflammation. We aimed to investigate an association between IL-1A and IL-6 gene polymorphisms and both hormonal/biochemical parameters and levels of IL-1A and IL-6. A total of 103 women diagnosed with PCOS according to ESHRE/ASRM criteria were investigated. The patients were divided into two groups as obese and non-obese. IL-1A and IL-6 genes polymorphisms as well as hormonal/biochemical parameters and levels of IL-1A and IL-6 were analysed in the same groups. Serum IL-1A and IL-6 levels were found to increase both in obese and non-obese groups. However, there was no association between IL-1A level and IL-1A polymorphism. A relationship was detected between H score, FSH, LH, total testosterone, HDL-C and TG levels and CG + GG genotypes of IL-6. Furthermore, an association was found between IL-6 levels and CC genotype of IL-6 in the obese PCOS patients. The abnormalities in hormonal/biochemical parameters detected in Turkish PCOS patients may be related with IL-6 gene polymorphism rather than IL-1A.

Association between Interleukin-6 gene -572G>C polymorphism and coronary heart disease

The association of the Interleukin 6 (IL-6) -572G>C polymorphism and risk of coronary heart disease (CHD) have been implicated in a large number of investigations, but the results remain debatable. This meta-analysis was performed to provide more compelling evidence for the connection between the IL-6 -572G>C polymorphism and CHD risk. Studies eligible for this meta-analysis were identified through electronic search of PubMed, EMBASE, and CNKI. The fixed effects model was performed to summarize an odds ratio (OR) with 95 % confidence interval (CI). The meta-analysis of 3,985 patients and 7,153 controls from 17 studies showed that the CC genotype carriers had 0.84-fold lower risk of developing CHD when compared with the carriers with the GC+GG genotypes (OR(CC vs. GC+GG) = 0.84; 95% CI = 0.75-0.95; P = 0.414; I(2) = 3.5%). The decreased risk of CHD was also found in Asians (OR = 0.87; 95% CI = 0.77-0.98; P = 0.227; I(2) = 22.7%) and Caucasians (OR = 0.60; 95% CI = 0.40-0.92; P = 0.958; I(2) = 0) under the same genetic comparison. The results of our meta-analysis revealed that the IL-6 -572G>C polymorphism may be linked with risk of CHD in a protective model.

Interleukin-6 C-572G gene polymorphism and coronary artery disease in Asian: a meta-analysis of 2511 subjects

The interleukin-6 (IL-6) C-572G gene polymorphism has been suggested to be associated with the increased coronary artery disease (CAD) risk, but the study results are still debatable. To explore the association between IL-6 C-572G gene polymorphism and CAD in the Asian population, the current meta-analysis involving 2511 subjects from 7 separate studies was conducted. The combined odds ratio (ORs) for the association between IL-6 C-572G gene polymorphism and CAD and their corresponding 95% confidence intervals (95% CIs) were assessed by random or fixed effect model. A significant association between IL-6 C-572G gene polymorphism and CAD was found in the Asian population under an allelic (OR: 1.50, 95% CI: 1.30-1.71, P<0.00001), recessive (OR: 2.221, 95% CI: 1.444-3.417, P=1.0×10(-10)) dominant (OR: 1.313, 95% CI: 1.188-1.451, P=1.0×10(-10)), homozygous (OR: 2.454, 95% CI: 1.606-3.751, P=1.0×10(-10)), heterozygous (OR: 3.01, 95% CI:1.99-4.55, P<0.00001) and additive genetic models (OR: 1.372, 95% CI: 1.231-1.528, P=1.0×10(-10)). In the Asian population, the IL-6 C-572G gene polymorphism was indicated to be correlated with CAD susceptibility. The carriers of -572G allele might be predisposed to CAD risk.

Genetic polymorphisms of interleukin-6 gene and susceptibility to coronary artery disease in Chinese population: Evidence based on 4582 subjects

The aim of this study was to explore whether interleukin-6 (IL-6) gene (-174 G/C and -572 C/G) polymorphisms are associated with susceptibility to coronary artery disease (CAD) risk in Chinese population. All the statistical tests were performed using Stata version 11.0. Twelve articles involving 16 studies were included in this meta-analysis, covering a total of 2309 CAD cases and 2273 controls. For IL-6 gene -572 C/G polymorphism, the results showed evidence for significant association between IL-6 gene -572 C/G polymorphism and CAD risk (for G allele vs. C allele: OR=1.48, 95% CI=1.26-1.74, p<0.001; for G/G vs. C/C: OR=2.60, 95% CI=1.54-4.39, p<0.001; for G/G vs. G/C+C/C: OR=2.15, 95% CI=1.35-3.42, p=0.001; for G/G+G/C vs. C/C: OR=1.55, 95% CI=1.29-1.85, p<0.001). However, for IL-6 gene -174 G/C polymorphism, no significant association was found between this variation and CAD risk. In summary, our meta-analysis showed evidence that IL-6 gene -572 C/G polymorphism may be a risk factor for CAD susceptibility. For IL-6 gene -174 G/C polymorphism, no significant association was found between this variation and CAD risk.

Single nucleotide polymorphisms in interleukin-6 and their association with venous thromboembolism

The aim of the present study was to reveal the contribution of single nucleotide polymorphisms of the interleukin‑6 (IL‑6) gene and the progression of venous thromboembolism (VTE). A case‑control study composed of 246 VTE patients, including 160 from the Han population (76 males and 84 females, mean age 57.41±13.25 years), 86 from the Uyghur population (41 males and 45 females, mean age 51.61±13.73 years) and 292 gender and ethnicity‑matched control participants, including 170 from the Han population (91 males and 79 females, mean age 55.82±11.83 years) and 122 from the Uyghur population (64 males and 58 females, mean age 53.52±13.64 years) were enrolled in the present study. The results demonstrated that the serum levels of IL‑6, C‑reactive protein (CRP), D‑dimer, fibrinogen, plasminogen activator inhibitor‑1 and leptin were significantly higher in the VTE group compared with the control group (P<0.05). The frequencies of the ‑572C/G promoter polymorphisms of the IL‑6 genotypes CC, CG and GG were identified to be 34, 48 and 18% in the Han population and 33, 47 and 20% in the Uyghur population, respectively. The allele frequency distributions of the C and G alleles were 58 and 42% in the Han population and 56 and 43% in the Uyghur population, respectively. Significant differences were identified in the ‑572C/G promoter polymorphisms between the VTE group and the control group (P<0.05). For the ‑597G/A polymorphism, all individuals carried the GG and GA genotype; AA genotypes were not detected. Logistic regression analysis was used to identify the risk factors for VTE, adjusting by confounding factors, the results of which demonstrated that the CC homozygote of the IL‑6 ‑572G/C, CRP, IL‑6 and high‑density lipoprotein‑cholesterol were independent risk factors of VTE (P<0.05). In conclusion, the ‑572G/C genotype of IL‑6 may be a genetic marker of VTE in the Han and Uyghur populations.

Association of Klotho and interleukin 6 gene polymorphisms with aging in Han Chinese population

Certain gene polymorphisms are associated with human aging. This study investigated polymorphisms of a metabolism-related gene, Klotho, and an inflammatory gene, IL6, for association with the aging process in a healthy Han Chinese population. A total of 482 healthy subjects were recruited and divided into aging and young groups according to chronological age and biological age. Snapshots were used to detect a Klotho gene tag SNP (rs571118) and the F-SNPs rs9536314 (F352V) and rs9527025 (C370S), and an interleukin 6 (IL-6) gene tag SNP (rs1524107) and the F-SNPs rs1800795 (-174G/C) and rs1800796 (-572G/C). Klotho F352V and IL-6-174G/C was G homozygous, C370S was T homozygous while IL-6-572G/C MAF less than 5%. There was a statistically significant difference in the Klotho rs571118 SNP between chronological age groups, but not biological age groups. However, other SNPs, including IL-6 gene SNPs, didn't correlate with age in the Han Chinese population. Human aging is a complex process that includes chronological and biological aging. Our current data showed that Klotho gene rs571118 SNP was associated with chronological aging, but not biological aging, in a Han Chinese population. Further study will investigate genetic build up for the difference between chronological and biological aging.

Genetic and environmental influences on the prospective correlation between systemic inflammation and coronary heart disease death in male twins

OBJECTIVE

Because of lack of evidence, we aimed to examine to what degree low-grade systemic inflammation and coronary heart disease (CHD) death shared common genetic and environmental substrates.

APPROACH AND RESULTS

From the 41-year prospective National Heart, Lung, and Blood Institute Twin Study, we included 950 middle-aged male twins at baseline (1969-1973). Low-grade systemic inflammation was measured with plasma levels of interleukin-6 (IL-6) and C-reactive protein. Univariate and bivariate structural equation models were used, adjusted for a risk score for CHD death. The score-adjusted heritability was 19% for IL-6, 27% for C-reactive protein, and 22% for CHD death. The positive phenotypic correlation of IL-6 with CHD death (radjusted=0.27; 95% confidence interval [CI], 0.08-0.43) was driven by additive genetic factors (contribution [relative contribution], 0.30 [111%]) but attenuated by unique environment (-0.03 [-11%]). The genetic correlation between IL-6 and CHD death was 0.74 (95% CI, 0.21-1.00), whereas the unique environmental correlation was -0.05 (95% CI, -0.35 to 0.25). The proportion of genetic variance for CHD death shared with that for IL-6 was 74%. The phenotypic correlation of C-reactive protein with CHD death (radjusted=0.10; 95% CI, -0.02 to 0.22) was explained by additive genetic factors (0.20 [149%]) but was attenuated by the unique environment (-0.09 [-49%]). The genetic correlation of C-reactive protein with CHD death was 0.63 (95% CI, -0.07 to 1.00), whereas the unique environmental correlation was -0.07 (95% CI, -0.29 to 0.17).

CONCLUSIONS

Low-grade systemic inflammation, measured by IL-6, and long-term CHD death share moderate genetic substrates that augment both traits.

Lack of association between a functional polymorphism (rs1800796) in the interleukin-6 gene promoter and lung cancer

Background

A number of studies have examined the association between interleukin-6 (IL-6) rs1800796 polymorphism and risk of lung cancer but revealed inconsistent results. The aim of this study was to clarify the association between IL-6 rs1800796 polymorphism and risk of lung cancer.

Methods

Literature databases including PubMed, Embase and CNKI were searched up to January 2014. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) under co-dominant model, dominant model and recessive model were estimated using random-effects model.

Results

A total of seven studies, including 2691 lung cancer cases and 3067 controls, were included in the meta-analysis. The results suggested that IL-6 rs1800796 polymorphism was not associated with risk of lung cancer under homogeneous co-dominant model (OR = 1.06, 95%CI = 0.73-1.54), heterogeneous co-dominant model (OR = 1.24, 95%CI = 0.96-1.60), dominant model (OR = 1.23, 95%CI = 0.95-1.58) and recessive model (OR = 0.96, 95%CI = 0.70-1.32). The association was still not significant in either never-smokers (OR = 1.19, 95%CI = 0.95-1.48) or ever-smokers (OR = 1.73, 95%CI = 0.89-3.36).

Conclusion

The present meta-analysis suggested that there was no association between IL-6 rs1800796 polymorphism and lung cancer, which was independent of smoking status.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1060061508127855

The effects of gene polymorphisms in interleukin-4 and interleukin-6 on the susceptibility of rheumatoid arthritis in a Chinese population

BACKGROUND

Interleukin-4 (IL-4) and interleukin-6 (IL-6) have been reported to associate with pathogenesis of rheumatoid arthritis (RA); however, the role of IL-4 and IL-6 genetic polymorphisms in RA remains unknown.

METHOD

A total of 752 unrelated Chinese patients with RA and 798 healthy Chinese volunteers with no family histories of any autoimmune diseases were recruited. The promoter IL-4-590 C/T and IL-6-174 G/C polymorphisms were genotyped.

RESULT

The genotype distributions and allele frequencies of IL-4-590 C/T and IL-6-174 G/C polymorphisms in RA patients were significantly different from healthy volunteers. Statistically significant differences were observed in genotypes for IL-4-590 and IL-6-174. The frequencies of both the T allele on the IL-4-590 and the C on the IL-6-174 were significantly increased in RA patients.

CONCLUSION

The IL-4-590 and IL-6-174 promoter polymorphisms may be associated with increased risk of RA and could be used as genetic marker for assessing the susceptibility and severity of RA in Chinese.

Association of A561C and G98T polymorphisms in E-selectin gene with coronary artery disease: a meta-analysis

Objective

E-selectin (SELE) mediates the rolling and adhesion of leukocytes on activated endothelial cells and plays a critial role in the pathogenesis of coronary artery disease (CAD). Associatons between the A561C and G98T polymorphisms of the SELE gene and CAD risk were investigated broadly, but the results were inconsistent. In the present study, we performed a meta-analysis to systematically evaluate the associations between the two polymorphisms and the risk of CAD.

Methods

Comprehensive research was conducted to identify relevant studies. The fixed or random effect model was selected based on the heterogeneity among studies, which was evaluated with Q-test and Ι². Meta-regression was used to explore the potential sources of between-study heterogeneity. Peters's linear regression test was used to estimate the publication bias.

Results

Overall, 24 articles involving 3694 cases and 3469 controls were included. After excluding articles deviating from Hardy–Weinberg equilibrium in controls and sensitive analysis, our meta-analysis showed a significant association between the A561C ploymprphism and CAD in dominant (OR  = 1.84, 95% CI  = 1.56–2.16) and codominant (OR  = 1.74, 95% CI  = 1.49–2.03) models. As for the G98T polymorphism, significantly increased CAD risk was observed in dominant (OR  = 1.47, 95% CI  = 1.16–1.87) and codominant (OR  = 1.48, 95% CI  = 1.18–1.86) models, but after subgroup analysis, the association was not significant among Caucasians in dominant (OR  = 1.58, 95% CI  = 0.73–3.41) and codominant (OR  = 1.58, 95% CI  = 0.79–3.20) models.

Conclusions

Despite some limitations, our meta-analysis suggested that the SELE gene polymorphisms (A561C, G98T) were significantly associated with increased risk of CAD. However, after subgroup analysis no significant association was found among Caucasians for the G98T polymorphism, which may be due to the small sample size and other confounding factors. Future investigations with multicenter, large-scale, and multi-ethnic groups are needed.

Increased basal and alum-induced interleukin-6 levels in geriatric patients are associated with cardiovascular morbidity

BACKGROUND/AIM OF THE STUDY

Low-grade systemic inflammation was suggested to participate to the decline of physiological functions and increased vulnerability encountered in older patients. Geriatric syndromes encompass various features such as functional dependence, polymorbidity, depression and malnutrition. There is a strong prevalence of cardiovascular diseases and related risk factors and chronic cytomegalovirus infections in the geriatric population. As these underlying conditions were proposed to influence the inflammatory state, the aim of this study was to assess their potential contribution to the association of geriatric syndromes with inflammatory parameters.

METHODOLOGY

We recruited 100 subjects in the general population or hospitalized for chronic medical conditions (age, 23-96 years). We collected information on clinical status (medical history, ongoing comorbidities, treatments and geriatric scales), biological parameters (hematological tests, cytomegalovirus serology) and cytokines production (basal and alum-induced interleukin (IL)-1β and IL-6 levels). Using stepwise backward multivariate analyses, we defined which set of clinical and biological variables could be predictive for increased inflammatory markers.

PRINCIPAL FINDINGS

We confirmed the age-associated increase of circulating IL-6 levels. In contrast to geriatric scales, we found history of cardiovascular diseases to be strongly associated for this parameter as for high IL-6 production upon ex vivo stimulation with alum.

CONCLUSIONS

Association between low-grade inflammation and geriatric conditions could be linked to underlying cardiovascular diseases.

An interleukin-6 gene promoter polymorphism is associated with polycystic ovary syndrome in South Indian women

PURPOSE

Polycystic ovary syndrome (PCOS) is a most common endocrine disorder of reproductive age women. Interleukin-6 is involved in the pathophysiological characteristics associated with polycystic ovary syndrome (PCOS). The-174 G/C IL-6 gene promoter region single nucleotide polymorphism (SNP) may influence or modulate gene function and/or transcriptional efficiency. The current study was aimed to evaluate the association between IL-6 gene -174 G/C promoter polymorphism and Polycystic Ovary Syndrome in South Indian women.

METHODS

In the present study, we examined the genotypic and allele distribution among the PCOS patients (n = 104) and controls (n = 156). The genotypes of IL-6 -174 G/C SNP were analyzed by polymerase chain reaction (PCR) and sequencing analysis. The allele frequency and genotype distributions of cases and controls were analyzed using Fisher's exact test.

RESULTS

The genotype frequencies observed among the 104 cases and 156 controls were G/G 66.3 % and 49.4 %, G/C 29.8 % and 46.8 %, and C/C 3.8 % and 3.8 % (OR: 1.6226, CI: 1.0574-2.4899). The G and C allele frequencies were 81.25 % and 72.8 %, and 18.75 % and 27.2 %, respectively. The genotype and allele distribution revealed significant differences between PCOS patients and controls (all P values < 0.05).

CONCLUSION

Our findings showed a significant statistical association between IL-6 -174 G/C SNP and PCOS risk in South Indian women. The 'G' allele frequency influences significantly higher in PCOS patients than controls. However, the exact mechanism by which 'G' allele frequency influence PCOS patients is yet to be determined.

The association between interleukin-6 gene polymorphisms and intracranial aneurysms: a meta-analysis

BACKGROUND

Interleukin-6 (IL-6) is an important proinflammatory cytokine, and some studies have demonstrated that IL-6 promoter polymorphisms (-174G/C and -572G/C) may be associated with intracranial aneurysms. A meta-analysis based on the evidence currently available from the literature was conducted to make a more precise estimation of this relationship.

METHODS

Electronic databases (the National Library of Medline and Embase databases) were searched before June 2013. Odds ratio (OR) and 95% confidence interval (CI) were calculated in fixed- or random-effects models when appropriate. Subgroup analyses were performed by race. This meta-analysis included six case-control studies, which included 1188 intracranial aneurysms cases and 4099 controls.

RESULTS

The combined results based on all studies showed that intracranial aneurysms cases had a significantly lower frequency of -572CC [OR (Recessive model) = 0.47, 95% CI = 0.36, 0.60, P < 0.001; OR (Codominant model) = 0.29, 95% CI = 0.20, 0.44, P < 0.001], -572GC [OR (Codominant model) = 0.73, 95% CI = 0.55, 0.98, P = 0.04] and -174CC [OR (Recessive model) = 0.73, 95% CI = 0.54, 0.98, P = 0.03; OR (Codominant model) = 0.70, 95% CI = 0.51, 0.97, P = 0.03] genotype. In the subgroup analysis by race, we found that (1) intracranial aneurysms cases had a significantly lower frequency of -572CC [OR (Recessive model) = 0.41, 95% CI = 0.32, 0.53, P < 0.001; OR (Codominant model) = 0.18, 95% CI = 0.12, 0.29, P < 0.001] and -572GC [OR (Codominant model) = 0.61, 95% CI = 0.42, 0.88, P = 0.009] genotype in Asians; (2) intracranial aneurysms cases had a significantly higher frequency of -572CC [OR (Recessive model) = 4.41, 95% CI = 1.35, 14.36, P = 0.01; OR (Codominant model) = 4.41, 95% CI = 1.35, 14.38, P = 0.01] genotype and lower frequency of -174CC [OR (Recessive model) = 0.73, 95% CI = 0.54, 0.98, P = 0.03; OR (Codominant model) = 0.70, 95% CI = 0.51, 0.97, P = 0.03] genotype in Caucasians.

CONCLUSIONS

Our meta-analysis suggested that IL-6 promoter polymorphisms (-174G/C and -572G/C) were associated with intracranial aneurysms. However, due to the small subjects included in analysis and the selection bias in some studies, the results should be interpreted with caution.