Interleukin-6 polymorphism (-634C/G) in the promotor region and the progression of diabetic nephropathy in type 2 diabetes

Association between the number of existing teeth and maintenance dialysis therapy: A cross-sectional study of adult male dentists

Dental caries and periodontal disease are typical oral diseases frequently observed in patients with renal diseases. Tooth loss is an outcome of dental caries and periodontal disease, and the number of existing teeth is an indicator of oral health status. However, the association between the number of existing teeth and end-stage kidney disease (ESKD) has not been investigated in detail. This study aimed to investigate the association between oral health status, expressed by the number of existing teeth, and ESKD. We analyzed data from the second survey of the Longitudinal Evaluation of Multi-phasic, Odontological, and Nutritional Associations in Dentists, a cohort study conducted among members of the Japan Dental Association. From August 2016 to July 2017, self-administered questionnaires were mailed to 16,128 male dentists and 8,722 responded. Among them, 7,479 men with complete data on age, number of existing teeth, and ESKD were included in the analysis. Multivariate logistic regression analysis was conducted, with ESKD as the dependent variable and the number of existing teeth (≥23 teeth and <23 teeth) as the independent variable. Subgroup analysis by age (<65 years and ≥65 years) was also conducted. The <23 teeth group had a significantly higher rate of ESKD than did the ≥23 teeth group. After adjusting for age, body mass index, smoking habits, hypertension, and diabetes mellitus, there was no significant association between having <23 teeth and ESKD in all participants. However, the subgroup analysis revealed a significant association after adjustment for covariates in participants aged <65 years but not in those aged ≥65 years. In conclusion, having <23 teeth was associated with the risk of requiring maintenance dialysis therapy among Japanese men aged <65 years. Therefore, tooth loss may be associated with renal function decline.

Impact of TNFRSF1B (rs3397, rs1061624 and rs1061622) and IL6 (rs1800796, rs1800797 and rs1554606) Gene Polymorphisms on Inflammatory Response in Patients with End-Stage Kidney Disease Undergoing Dialysis

We aimed to study the impact of polymorphisms in the genes encoding interleukin-6 (IL6) and tumor necrosis factor receptor-2 (TNFR2), reported to be mortality risk predictors, in patients with end-stage kidney disease (ESKD) undergoing dialysis. TNFRSF1B (rs3397, rs1061624, and rs1061622) and IL6 (rs1800796, rs1800797, and rs1554606) polymorphisms were studied in patients with ESKD and controls; the genotype and allele frequencies and the associations with inflammatory and erythropoiesis markers were determined; deaths were recorded throughout the following two years. The genotype and allele frequencies for the TNFRSF1B rs3397 polymorphism were different in these patients compared to those in the controls and the global and European populations, and patients with the C allele were less common. Patients with the CC genotype for TNFRSF1B rs3397 presented higher hemoglobin and erythrocyte counts and lower TNF-α levels, suggesting a more favorable inflammatory response that seems to be associated with erythropoiesis improvement. Patients with the GG genotype for TNFRSF1B rs1061622 showed lower serum ferritin levels. None of the TNFRSF1B (rs3397, rs1061624, and rs1061622) or IL6 (rs1800796, rs1800797, and rs1554606) polymorphisms had a significant impact on the all-cause mortality rate of Portuguese patients with ESKD.

Genetic polymorphisms as predictive biomarkers of adverse events during preoperative chemotherapy in esophageal cancer

PURPOSE

This study aimed to explore associations between genetic polymorphisms and adverse effects due to preoperative chemotherapy with docetaxel, cisplatin, and fluorouracil (DCF) for esophageal cancer.

METHODS

Preoperative DCF (docetaxel, 70 mg/m2/day, day 1; cisplatin, 70 mg/m2/day, day 1; fluorouracil, 750 mg/m2/day, days 1-5) was repeated every 3 weeks for up to three cycles. Genotyping of nine candidate genetic polymorphisms was conducted using blood samples from the enrolled patients.

RESULTS

According to a multivariable analysis evaluating 50 patients, grade 3 or worse neutropenia was more likely to occur in those with the ABCC2-24C/T or T/T genotype (rs717620) (OR, 5.30, P = 0.013). Additionally, patients with the TYMS 3'-UTR 0 bp/0 bp genotype (rs151264360) showed a trend toward grade 3 or worse hyponatremia (OR, 0.16, P = 0.005). Grade 2 or worse thrombocytopenia was more likely to occur in patients with the TNF-α-1031C/T or T/T genotype (rs1799964) (OR, 6.30, P = 0.016) and IL-6-634C/C genotype (rs1800796) (OR, 0.18, P = 0.034), and grade 2 or worse anemia was more likely to occur in patients with the MCP-1-2518G/G genotype (rs1024611) (OR, 0.19, P = 0.027).

CONCLUSIONS

ABCC2-24C > T (rs717620), TYMS 3'-UTR 6-bp indel (rs151264360), TNF-α-1031T > C (rs1799964) as well as IL-6-634G > C (rs1800796), and MCP-1-2518A > G (rs1024611) polymorphisms might serve as independent and predictive biomarkers for neutropenia, hyponatremia, thrombocytopenia, and anemia, respectively, during preoperative chemotherapy with docetaxel, cisplatin, and fluorouracil for patients with esophageal cancer.

Associations between the polymorphisms of main components in PI3K/Akt pathway and risk of diabetic kidney disease: A meta-analysis

AIMS

Diabetic kidney disease (DKD) is a severe microvascular complication frequently associated with type 1 and type 2 diabetes mellitus. The objective of this work was to evaluate the relevance of PI3K/Akt pathway polymorphisms and DKD susceptibility by a meta-analysis.

METHODS

Case-control studies related to the relationship between PI3K/Akt pathway polymorphisms and DKD risk were searched from Pubmed, Embase, Cochrane Library, SINOMED, CNKI, and Wanfang databases. Statistical analysis and heterogeneity test were conducted by Review Manager 5.4.

RESULTS

Totally, 52 eligible studies were enrolled, including seven single nucleotide polymorphisms (SNPs) for four genes in the PI3K/AKT pathway (GNB3: rs5443; eNOS: rs1799983, rs869109213, rs2070744; IL-6: rs1800795, rs1800796; TNFα: rs1800629). The "M" allele of eNOS rs1799983 was related to the increased risk of DKD under random effects model, especially in Asian population (Overall:M vs. W: I2  = 75%, OR = 1.29, 95%CI 1.07-1.56; MM + WM vs. WW: I2  = 75%, OR = 1.50, 95%CI 1.21-1.86). The "M" allele of eNOS rs869109213 was implicated with higher prevalence of DKD under random effects model, especially in Asian population (Overall:M vs. W: I2  = 63%, OR = 1.43, 95%CI 1.22-1.68; MM + WM vs. WW: I2  = 50%, OR = 1.36, 95%CI 1.16-1.58; MM vs. WM + WW: I2  = 59%, OR = 2.20, 95%CI 1.41-3.43). The "M" allele of eNOS rs2070744 was implicated with higher prevalence of DKD under random effects model, especially in Indian population (Overall: M vs. W: I2  = 47%, OR = 1.35, 95%CI 1.15-1.59; MM + WM vs. WW: I2  = 45%, OR = 1.32, 95%CI 1.07-1.62; MM vs. WM + WW: I2  = 65%, OR = 2.29, 95%CI 1.39-3.77). The "M" allele of IL-6 rs1800796 was predominately associated with higher DKD risks under random effects model, especially in Asian population (Overall: M versus W: I2  = 23%, OR = 1.49, 95%CI 1.21-1.84; MM + WM vs. WW: I2  = 1%, OR = 1.43, 95%CI 1.15-1.77; MM + WM vs. WW: I2  = 71%, OR = 2.77, 95%CI 1.09-7.06).

CONCLUSIONS

This meta-analysis indicated that polymorphisms in the PI3K/Akt pathway in eNOS rs1799983, rs869109213, rs2070744, and IL-6 rs1800796 were related to the increased risk of DKD.

Association of the IL-6 gene rs1800796 polymorphism with recurrent pregnancy loss in a population of women from northwestern China: a case-control study

We aimed to identify whether IL-1β (rs1143627, rs1143634 and rs16944), IL-6 (rs1800796), IL-10(rs1800872 and rs1800896), and vascular endothelial growth factor (VEGF) (rs1570360) gene polymorphisms were risk factors for recurrent pregnancy loss (RPL) in a population of women in northwestern China. A total of 150 women with a history of two or more unexplained and consecutive spontaneous abortions before their 24th gestational week and 150 age-matched women with at least two normal pregnancies and no history of pregnancy loss were included in the present study as cases and controls, respectively. We extracted genomic DNA from peripheral blood, and executed genotyping with the SNaPshot technique. Logistic regression analysis was conducted to determine the odds ratios (ORs) of the associations between the polymorphisms and RPL. Of the seven polymorphisms we studied, only IL-6 rs1800796 showed a statistically significant association with RPL, as we noted an elevated risk of RPL with the G allele (OR = 1.57; 95% CI, 1.10-2.24; p = .01). The risk of RPL in women with the GG + CG genotype (OR = 1.96; 95% CI, 1.19-3.21; p = .01) was also higher than that in women with the CC genotype. The present study thus indicated that the IL-6 gene rs1800796 polymorphism may serve as an important risk factor for RPL in this group of women from northwestern China.IMPACT STATEMENTWhat is already known on this subject? Cytokine and vascular endothelial growth factor (VEGF) gene polymorphisms may affect the risk of recurrent pregnancy loss (RPL) by modulating cytokine and VEGF expression.What do the results of this study add? The study results showed that the IL-6 rs1800796 single-nucleotide polymorphism constituted a risk factor for RPL in a population of women in northwestern China.What are the implications of these findings for clinical practice and/or further research? This study clearly reflects clinical significance as it provides a theoretical basis for the early screening of RPL by revealing that the IL-6 gene rs1800796 polymorphism increased the risk of RPL in women in northwestern China.

Suggestive evidence of genetic association of -572G > C polymorphism with primary open angle glaucoma in a North Indian Punjabi population

BACKGROUND

IL6 is an important candidate gene implicated in the pathogenesis of glaucoma. The present study assessed the genetic association of -174G > C and -572G > C polymorphisms in the IL6 promoter region with primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) in a north Indian Punjabi cohort.

METHODS

910 subjects (313 POAG, 148 PACG cases and 449 controls) were recruited. Genotyping was done by TaqMan assays. Genetic association was tested under different genetic models using Plink. Diplotype and linkage disequilibrium (LD) analysis was done through Haploview. Association of clinical parameters with the genotypes was assessed by one-way ANOVA. Adjustment for potential confounding variables was done by binary logistic regression. IL6 levels were measured in POAG patients and controls.

RESULTS

572G > C variant showed marginal difference in genotype frequency between pooled cases and POAG subgroup with respect to controls (p = 0.042; OR = 1.33; and p = 0.041; OR = 1.37). The GC genotype conferred 1.37-fold protection under codominant model in POAG cases (p = 0.034, OR = 1.37, 95% CI = 1.02-1.85; p_corr = 0.025, OR = 1.45, 95% CI = 1.04-2.02). The mean value for IOP was elevated among cases having 'CC' genotype at the -572G > C locus (p = 0.037). Lower levels of IL6 were detected in POAG patients in plasma samples (p = 0.0001).

CONCLUSION

The study reports suggestive evidence for -572G > C variant in IL6 in affecting genetic susceptibility to POAG in the targeted North Indian Punjabi cohort. A correlation of IL6 levels in aqueous humor (AH) and systemic circulation in POAG was observed, the functional and diagnostic relevance of which may be further investigated.

Th2 cell regulatory and effector molecules single nucleotide polymorphisms and periodontitis

To investigate the association between T helper 2 (Th2) cell regulatory and effector molecules' genetic polymorphisms and periodontitis. Single nucleotide polymorphisms (SNPs) of 11 Th2 cell regulatory or effector molecules genes (CD28, CTLA4, IL4, IL5, IL6, IL9, IL10, IL13, IL4R, GATA3, STAT6, and rs1537415; total 130 SNPs) were studied in Chinese nonsmokers (163 periodontitis-free controls, 141 periodontitis patients) using Sequenom iPlex assays. SNPs potentially associated with periodontitis (adjusted allelic P < 0.1) in this cross-sectional study were further investigated via meta-analysis. Allele G of rs4553808 in promoter of CTLA4 was more frequently detected in periodontitis than controls (P < 0.005), but did not remain significant after age and gender adjustment. Haplotype (GTT) in a block of three CTLA4 SNPs (rs4553808, rs16840252, rs5742909) was significantly associated with periodontitis. Meta-analysis of SNPs identified indicated allele T of CTLA4 rs5742909 (3 studies; 461 control, 369 periodontitis) and allele G of IL6 rs1800796 (18 studies; 2760 control, 2442 periodontitis) were significantly associated with periodontitis (OR = 1.44 and OR = 1.30, respectively). Within limitations of this study, a haplotype of CTLA4 concerning Th2 cell regulation, may be associated with periodontitis in Chinese nonsmokers followed. Meta-analysis indicated rs5742909 of CTLA4 and rs1800796 of IL6 appeared significantly associated with periodontitis.

Meta-analysis of association between il-6-174 g/c polymorphism and female infertility related disorders

Female infertility continues to increase in prevalence annually and factors causing it need to be researched. As IL-6-174 G/C polymorphism is known to alter the plasma levels of IL-6, abnormal levels of IL-6 found in infertile females could be due to genetic reasons. With the understanding of the importance of IL-6 in reproductive physiology, several individual studies done so far to find the association of this polymorphism with female infertility related disorders were systematically combined for meta-analysis. Articles were searched using electronic data base sources and were included based on specific criteria. Finally, eight articles which includes polycystic ovarian syndrome (PCOS; n = 4), endometriosis (n = 3) and tubal damage (n = 1) were selected for the analysis. Results showed statistically significant heterogeneity across studies under the allele model (p < 0.0001, I² = 78 %) and dominant model (p < 0.00001, I² = 82%) but not under recessive model (p = 0.31, I² = 16%). This difference could be possibly due to variation in ethnicity, lifestyle, age or BMI related factors. The pooled odds ratio under the three genetic models were 0.87(CI = 0.75-1.02), 0.77 (CI = 0.63-0.94) and 1.05 (CI = 0.76-1.46) respectively. Sub group analysis showed statistical significant (P < 0.01) for PCOS under allele and dominant model, but not for endometriosis and tubal damage. By this meta-analysis, we can say that IL-6-174 G/C polymorphism can be considered as a potential genetic marker for PCOS but not for endometriosis and tubal damage disorders. However, more studies with adequate sample sizes are required to be done in endometriosis, tubal disease and other female infertility disorders to arrive at a definite conclusion.

Role of Interleukin-6 in Depressive Disorder

Major depressive disorder (MDD), which is a leading psychiatric illness across the world, severely affects quality of life and causes an increased incidence of suicide. Evidence from animal as well as clinical studies have indicated that increased peripheral or central cytokine interleukin-6 (IL-6) levels play an important role in stress reaction and depressive disorder, especially physical disorders comorbid with depression. Increased release of IL-6 in MDD has been found to be a factor associated with MDD prognosis and therapeutic response, and may affect a wide range of depressive symptomatology. However, study results of the IL6 genetic effects in MDD are controversial. Increased IL-6 activity may cause depression through activation of hypothalamic-pituitary-adrenal axis or influence of the neurotransmitter metabolism. The important role of neuroinflammation in MDD pathogenesis has created a new perspective that the combining of blood IL-6 and other depression-related cytokine levels may help to classify MDD biological subtypes, which may allow physicians to identify the optimal treatment for MDD patients. To modulate the IL-6 activity by IL-6-related agents, current antidepressive agents, herb medication, pre-/probiotics or non-pharmacological interventions may hold great promise for the MDD patients with inflammatory features.

The profiles of microRNAs from urinary extracellular vesicles (EVs) prepared by various isolation methods and their correlation with serum EV microRNAs

AIMS

MicroRNAs (miRNAs) that circulate in biological fluids are frequently enclosed in extracellular vesicles (EVs). However, urinary EVs and their cargo miRNAs have not been systematically studied according to their EV isolation methods.

METHODS

In type 2 diabetes mellitus persons with diabetic nephropathy (n = 4), we compared miRNA species in urine EVs prepared by ultracentrifugation (UC), qEV original size exclusion column (qEV), ExoQuick-TC Plus (ExoQuick), and ultrafiltration using Amicon Ultra centrifugal filter devices (Amicons) 10 K and 100 K. EV miRNAs were profiled by next-generation sequencing (NGS). Additionally, we evaluated the correlations of EV miRNA expression between the urine and serum samples isolated by UC.

RESULTS

From each of 100 ml of urine, the UC method yielded the highest number of EV miRNA species (233 ± 37.3), with the ExoQuick yielded the lowest (103 ± 17.4). Urine EV miRNA profiles were highly correlated between UC, qEV, ExoQuick and Amicon 10 K methods. EV miRNA profiles between the urine and serum samples showed variable correlations between the patients (paired sample number = 3, r = 0.39-0.72).

CONCLUSIONS

UC, qEV, ExoQuick, and Amicon 10 K are acceptable for urinary EV isolation to profile miRNAs. Urine- and serum-derived EV miRNA profiles have variable correlations depending on specific patients.

Association Between IL-6 Polymorphisms and Diabetic Nephropathy Risk: A Meta-analysis

BACKGROUND

The objective of this work was to evaluate the relevance of frequent interleukin-6 (IL-6) polymorphisms and diabetic nephropathy (DN) susceptibility by a systematic meta-analysis.

MATERIALS AND METHODS

The included studies related to the relationship between IL-6 and DN risk were searched from Pubmed, Embase and the Cochrane Library, and the Newcastle-Ottawa Scale was used to evaluate the study quality. A heterogeneity test was performed to determine the appropriate effect models based on the Q test and I² statistic. Odds ratios with 95% confidence intervals were used to determine the strength of associations. Afterwards, subgroup analysis was conducted to assess the effect of specific factors on the corresponding results. Additionally, publication bias and sensitivity analysis were also undertaken.

RESULTS

In total, 11 eligible articles were obtained. The meta-analysis revealed that the "C"allele of IL-6 rs1800795 was related to the decreased risk of DN (C versus G: P = 0.0471). The "G"allele of IL-6 rs1800796 was predominately associated with higher DN risks (GG versus CC: P = 0.0194; GG versus CC + GC: P = 0.0196). The "C"allele of IL-6 rs1800797 was implicated with higher prevalence of DN (C versus G: P = 0.0001; CC versus GG: P = 0.0003; CC versus GG + CG: P = 0.0227; CC + CG versus GG: P = 0.0001) while IL-6 rs2069837 and rs2069840 were not correlated with the susceptibility to DN.

CONCLUSIONS

This meta-analysis indicated that IL-6 rs1800795, rs1800796 and rs1800797 played important roles in DN development while IL-6 rs2069837 and rs2069840 might not be related to DN.

The interactions of physical activity, exercise and genetics and their associations with bone mineral density: implications for injury risk in elite athletes

Low bone mineral density (BMD) is established as a primary predictor of osteoporotic risk and can also have substantial implications for athlete health and injury risk in the elite sporting environment. BMD is a highly multi-factorial phenotype influenced by diet, hormonal characteristics and physical activity. The interrelationships between such factors, and a strong genetic component, suggested to be around 50-85% at various anatomical sites, determine skeletal health throughout life. Genome-wide association studies and case-control designs have revealed many loci associated with variation in BMD. However, a number of the candidate genes identified at these loci have no known associated biological function or have yet to be replicated in subsequent investigations. Furthermore, few investigations have considered gene-environment interactions-in particular, whether specific genes may be sensitive to mechanical loading from physical activity and the outcome of such an interaction for BMD and potential injury risk. Therefore, this review considers the importance of physical activity on BMD, genetic associations with BMD and how subsequent investigation requires consideration of the interaction between these determinants. Future research using well-defined independent cohorts such as elite athletes, who experience much greater mechanical stress than most, to study such phenotypes, can provide a greater understanding of these factors as well as the biological underpinnings of such a physiologically "extreme" population. Subsequently, modification of training, exercise or rehabilitation programmes based on genetic characteristics could have substantial implications in both the sporting and public health domains once the fundamental research has been conducted successfully.

Genetic variations in key inflammatory cytokines exacerbates the risk of diabetic nephropathy by influencing the gene expression

BACKGROUND

Diabetic nephropathy is the single strongest predictor of mortality in patients with diabetes. The development of overt nephropathy involves important inter-individual variations, even after adjusting for potential confounding influences of modifiable and non-modifiable risk factors. Genome-wide transcriptome studies have reported the activation of inflammatory signaling pathways and there is mounting indication of the role of genetic factors.

METHODS

We screened nine genetic variations in three cytokine genes (TNF-α, IL-6 and IL-β) in 1326 unrelated subjects comprising of healthy controls (n = 464), type 2 diabetics with nephropathy (DN, n = 448) and type 2 diabetes without nephropathy (T2D, n = 414) by sequence-specific amplification. Functional implication of SNPs was elucidated by correlation studies and relative gene expression using Realtime-Quantitative PCR (RT-qPCR).

RESULTS

Individual SNP analysis showed highest association of IL-1β rs16944-TT genotype (OR = 3.51, 95%CI = 2.36-5.21, P = 0.001) and TNF-α rs1800629-AA genotype (OR = 2.75, 95% CI = 1.64-4.59, P = 0.001) with T2D and DN respectively. The haplotype frequency showed significant risk of seven combinations among T2D and four combinations among DN subjects. The highest risk of T2D and DN was associated with GGTGAGTTT (OR = 4.25, 95%CI = 3.3-14.20, P = 0.0016) and GACGACCTT (OR = 21.3, 95%CI = 15.1-28.33, P = 0.026) haplotypes respectively. Relative expression by RT-qPCR showed increased cytokine expression in cases as compared to controls. TNF-α expression was increased by more than four-folds (n-fold = 4.43 ± 1.11) in DN. TNF-α, IL-6 and IL-1β transcript levels were significantly modulated by promoter region SNPs.

CONCLUSIONS

The present study implicates a strong association between cytokine TNF-α, IL-6 and IL-1β gene promoter polymorphisms and modulation of transcript levels with susceptibility to nephropathy in diabetes subjects.

IL-6 and IL-18 cytokine gene variants of pulmonary tuberculosis patients with co-morbid diabetes mellitus and their household contacts in Hyderabad

PURPOSE

Association of cytokine genes reflects their susceptibility towards infection and disease in household contacts (HHC) of pulmonary tuberculosis (PTB) patients. Hyperglycemia, a common factor in diabetics might influence their risk towards mycobacterium tuberculosis infection and disease development. This study determines the association of IL-6 and IL-18 cytokine gene variants of TB patients with diabetes mellitus (TBDM) and their HHC in Hyderabad.

METHODS

Single nucleotide polymorphisms of IL-6 (-174 G>C and -572 G>C) and IL-18 (-137 G>C and -607 C>A) cytokine genes were genotyped by Amplification Refractory Mutation System and Restriction Fragment Length polymerase chain reaction in total of 705 subjects comprising of TBDM, their HHC, PTB, DM and Healthy controls (HC).

RESULTS

At IL-6 -174G>C variant, GG genotype, G allele in TBDM and TBDM HHC, at -572G>C variant, C allele in TBDM and GG haplotype in TBDM HHC were showing positive association, however DM have not shown any association at IL-6 polymorphic sites. With respect to the IL-18 gene polymorphisms, at -137 G>C variant, GG genotype was positively associated in PTB while at -607 C>A variant positive association was shown with AC genotype in TBDM, their HHC and DM; GACC diplotype in TBDM and GCGC in PTB.

CONCLUSION

Our findings suggest that susceptible combination of IL-6 and IL-18 cytokine genes associated with disease in the HHCs highlight their risk of inclination towards the disease.

Study of IL4-590C/T and IL6-174G/C Gene Polymorphisms in Type 2 Diabetic Patients With Chronic Kidney Disease in North Indian Population

To explore the associations between potential functional promoter polymorphisms in pro-inflammatory and anti-inflammatory (IL-4(-590C/T) and IL-6(-174G/C) cytokine genes, and kidney dysfunction in North Indian type 2 diabetic subjects with chronic kidney disease. A total of 150 subjects aged 25-75 year were included in this study. The glomerular filtration rate (GFR) and serum creatinine were estimated. PCR was performed to analyse genotype distribution in IL-4 (-590T/C) and IL-6 (-174G/C) among healthy, type 2 diabetic patients with or without CKD. The genotype distributions were determined by Hardy-Weinberg equilibrium. CKD patients showed lower GFR (59.36 ± 1.33 ml/min/1.73 m² ) and higher serum creatinine (1.93 ± 0.99% mg) level in comparison to diabetic patients without CKD and healthy subjects. Genotypic distribution of the different genotypes among the study groups in IL-4 gene was genotype CC = 30, TC = 12, and TT = 8 in CKD patients. In type 2 diabetic patients without CKD, genotype distribution was CC = 38, TC = 10, and TT = 2. In healthy subjects, distribution of genotype was CC = 35, TC = 14, and TT = 1. The distribution of different genotype among the study groups for IL-6 gene was GG = 27, GC = 20, and CC = 3 in healthy subjects; GG = 28, GC = 19, and CC = 3 in diabetic patients without CKD and GG = 38, GC = 11, and CC = 1 in diabetic patients with CKD. There was no significant difference in the distribution of genotype frequencies between healthy subjects and diabetic patients without CKD but a significant difference was found in diabetic patients with CKD. The functional promoter polymorphisms IL4-590C/T and IL6-174G/C, which affect the IL-4 and IL-6 levels in north Indian subjects, were associated with kidney dysfunction and CKD. J. Cell. Biochem. 118: 1803-1809, 2017. © 2016 Wiley Periodicals, Inc.

Interleukin 6 (IL-6) and IL-10 Promoter Region Polymorphisms Are Associated with Risk of Lumbar Disc Herniation in a Northern Chinese Han Population

AIM

This study assessed the association of single-nucleotide polymorphisms (SNPs) in the proinflammatory cytokines interleukin 6 (IL-6) and IL-10 with the risk of lumbar disc herniation in a Chinese Han population.

METHODS

We collected blood samples from 267 patients with lumbar disc herniation (case group) and 300 normals (control group) and performed analyses of the IL-6 572C/G and 174G/C SNPs as well as the IL-10 592A/C and 1082G/A SNPs using TaqMan technology.

RESULTS

The frequencies of the IL-6-572 GG, GC, and CC genotypes were 5.99%, 42.3%, and 51.6%, respectively, in the case group, and 1.6%, 24%, and 64.3%, respectively, in the control group. Thus, the relative risk of the IL-6-572 G genotype (GG plus GC) was 1.69-fold higher for developing lumbar disc herniation compared to the CC genotype (95% confidence interval: 1.16-2.39, p < 0.01). The risks associated with the IL-6-572 CG and GG genotypes were 1.55- and 4.48-fold higher, respectively, versus the CC genotype for developing lumbar disc herniation (p < 0.01). The IL-10-1082 AG genotype was significantly higher in the case group (26.22%) versus the control group (11.67%); whereas the AA genotype was lower in the case group (73.78%) versus the control group (88.33%; p < 0.05). The IL-10-1082 G allele frequency was significantly higher in the case group (13.11%) versus the control group (5.83%; p < 0.05).

CONCLUSION

This study demonstrates that genetic variants in the promoter regions of the IL-6 and IL-10 genes are associated with lumbar disc herniation risk in this Northern Chinese Han population.

Interleukin-6 gene polymorphisms correlate with the progression of nephropathy in Chinese patients with type 2 diabetes: A prospective cohort study

AIMS

Interleukin-6 (IL-6), an inflammatory cytokine, is considered a candidate gene possibly involved in susceptibility to nephropathy in diabetes. This study aimed to examine whether IL-6 polymorphisms predict the progression of nephropathy in a prospective Chinese cohort of patients with type 2 diabetes.

METHODS

A total of 568 type 2 diabetic patients with normoalbuminuria at baseline were followed up for a mean of 5.3±1.5years. Urinary albumin-to-creatinine ratio (ACR) ⩾30mg/g in two consecutive urine tests were defined as progression to diabetic nephropathy (n=143). Five polymorphisms of IL-6 gene, rs1800795, rs1800796, rs1524107, rs2069837, and rs2069840, were genotyped. Cox proportional hazard models were used to estimate hazard ratio (HR) and 95% CI of progression to diabetic nephropathy under different genetic models.

RESULTS

Almost all patients (99.6%) carried the rs1800795 GG homozygous genotypes. In the Cox proportional models adjusted for multiple covariates, the HR under recessive model was 2.02 for rs1800796 GG (vs. CC+CG, 95% CI: 1.08-3.75, p=0.027), 2.37 for rs2069837 GG (vs. AA+AG, 95% CI: 1.15-4.87, p=0.019), and 2.08 for rs1524107 CC (vs. TT+TC, 95% CI: 1.12-3.89, p=0.021). These associations remained significant for rs1800796 and rs1524107 after correction for multiple testing (α=0.017). Overall, our results suggest that rs1800796 GG and rs1524107 CC homozygous genotypes may confer a greater risk for development of nephropathy in type 2 diabetes.

CONCLUSIONS

IL-6 gene polymorphisms rs1800796 and rs1524107 may serve as predictors of progression of nephropathy in Chinese patients with type 2 diabetes.

Significant impact of IL-6 -174G/C but inverse relation with -634 C/G polymorphism in patients with non-small cell lung cancer in Kashmiri population

To study the possible role of proinflammatory interleukin 6 -174 G>C (rs 1800795) and -634 C>G (rs 1800796) polymorphism in the pathogenesis of non-small cell lung cancer (NSCLC). A total of 190 NSCLC patients and 200 healthy controls were evaluated for polymorphic analysis of -174 G/C and -634 C/G by PCR-RFLP followed by DNA sequencing. A significant association was observed in the genotypic and allelic distribution of IL-6 -174 G/C in the NSCLC group as compared to control group [OR = 2.7 (1.77-4.11), p < 0.0001]. Smokers with the -174C allele were found to be significantly associated with NSCLC (p = 0.01), while 634C/G SNP showed an inverse relation [OR-0.4, p < 0.0001]. The present investigation revealed a significant association of the IL6 -174 G/C gene promoter polymorphism with NSCLC, and thus, the IL-6 -174G/C genotype can be considered as one of the biological markers in the etiology of NSCLC.

Investigation of relationship between IL-6 gene variants and hypertension in Turkish population

Hypertension (HT) is a common and life threating health problem worldwide leading to stroke, heart attack and renal failure. It is characterized by elevated blood pressure forced heart load. Human interleukin-6 (IL-6) and C- reactive protein (CRP) are known to be involved in inflammatory processes. IL-6 gene is a polymorphic gene which -174 G/C is a common and -572 G/C is a rare polymorphisms identified in promoter region. Publications on IL-6 gene polymorphisms raised the question whether this gene polymorphisms lead to susceptibility to HT or not. To investigate the effects of IL-6 gene -174 G/C (rs 1800795) and -572 G/C (rs1800796) polymorphisms on plasma IL-6 and CRP levels and their associations with hypertension disease in Turkish population we analyzed -174 G/C and -572 G/C polymorphisms and plasma IL-6 and CRP levels in 111 healthy controls and 108 hypertension patients from Adıyaman, Turkey. We determined the genotypes using polymerase chain reaction-restriction fragment length polymorphism and analyzed plasma levels of IL-6 by ELISA and CRP by automated standard biochemical methods. We have found no statistically significant differences between IL-6 gene -174 G/C and -572 G/C genotypes and allelic frequencies and IL-6 and CRP plasma levels and HT (p > 0.05). No CC genotype was found in control subjects for -572 G/C polymorphism. In conclusion, we found relation to -174 G/C and -572 G/C gene variants between neither IL-6 and CRP levels nor hypertension. The -572 G allele and GG genotype are predominant in Turkish population in Adıyaman, Turkey whereas the CC genotype is very rare.

Amino- and Carboxyl-Terminal CCR5 Mutations in Brazilian HIV-1-Infected Women and Homology Model of p.L55Q CCR5 Mutant

Genetic factors from an HIV-1 host can affect the rate of progression to AIDS and HIV infection. To investigate the frequency of mutations in the CCR5 gene, HIV-1 samples from infected women and uninfected individuals were selected for sequencing of the CCR5 gene regions encoding the N- and C-terminal protein domains. Physicochemical CCR5 modeling and potential protein domain analysis were performed in order to evaluate the impact of the mutations found in the properties and structure of CCR5. The p.L55Q mutation in the N-terminal protein domain was observed only in uninfected individuals, with an allelic frequency of 1.8%. Physicochemical analysis revealed that the p.L55Q mutation magnified the flexibility and accessibility profiles and the modeling of CCR5 structures showed resulting in a small deviation to the right, as well as a hydrophobic to hydrophilic property alteration. The p.L55Q mutation also resulted in a slight modification of the electrostatic load of this region. Additionally, three novel silent mutations were found at the C-terminal coding region among HIV-1-infected women. The results suggest that the p.L55Q mutation might alter CCR5 conformation. Further studies should be conducted to verify the role of this mutation in HIV-1 susceptibility.

Association of polymorphisms in IL6 gene promoter region with type 1 diabetes and increased albumin-to-creatinine ratio

BACKGROUND

Pro-inflammatory cytokines, such as interleukin-6 (IL-6), have been considered as key factors in type 1 diabetes mellitus (T1DM) and diabetic nephropathy, thus, our aim was to investigate the association of IL6-174G>C (rs1800795) and -634C>G (rs1800796) polymorphisms with T1DM susceptibility and diabetic nephropathy.

METHODS

These polymorphisms were analyzed in 144 children and adolescents with T1DM and 173 normoglycemic control subjects. Glycemic control, laboratory parameters of kidney function and serum lipids were evaluated. By studying only T1DM patients, we evaluated the polymorphisms associated with relevant biochemical parameters in various genetic models.

RESULTS

Type 1 diabetes mellitus patients showed poor glycemic control and albumin-to-creatinine ratio, total cholesterol and LDL-cholesterol levels increased when compared with normoglycemic subjects (p < 0.001, p = 0.004 and p < 0.001, respectively). IL6-174C allele was associated with an increased risk of developing T1DM (OR = 1.53, CI = 1.01-2.31, p = 0.044). In the T1DM group, IL6-174CC carriers showed higher concentrations of glycated hemoglobin (p = 0.029), albumin-to-creatinine ratio (p = 0.021), total cholesterol (p = 0.010), and LDL-cholesterol (p = 0.002), when compared with GG+GC carriers. No association was found for the IL6-634C>G polymorphism.

CONCLUSIONS

These results suggest that IL6-174G>C may contribute to T1DM and increased albumin-to-creatinine ratio as well as to poor glycemic control and hyperlipidemia.

Associations between polymorphisms of interleukin-6 and related cytokine genes and serum liver damage markers: a cross-sectional study in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study

Cytokines, including interleukin-6 (IL-6), play an important role in the liver. The aim of this study was to investigate associations between common polymorphisms in potential functional promoters of cytokine genes and liver damage markers among enrollees of a large Japanese cohort study. Subjects included 3257 Japanese individuals (1608 men and 1649 women, aged 35-69 years). Six single nucleotide polymorphisms (SNPs) in the promoter regions of five cytokine genes, IL1B (T-31C), IL6 (C-634G), IL8 (T-251A), IL10 (T-819C), tumor necrosis factor-A (TNFA) (T-1031C), and TNFA (C-857T), were genotyped by polymerase chain reaction. Information regarding alcohol intake, smoking habits, height, and weight was collected by a self-administered questionnaire. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured during a routine health check-up. Of the six SNPs genotyped, an IL6 polymorphism (rs1800796, C-634G) was most strongly associated with a liver damage marker, AST. Mean serum AST was significantly different among the three genotypes (mean ± SD, 22.7 ± 7.3 IU/L for CC, 22.8 ± 7.7 IU/L for CG, and 24.3 ± 8.6 IU/L for GG, p=0.011 by analysis of variance). The differences remained significant after adjustment for potential confounders by general linear models. The variations in mean serum AST and ALT levels were marked especially among men. Thus, the functional polymorphism IL6 C-634G may affect serum AST and ALT levels, possibly through different IL-6 production.

Response to the dipeptidyl peptidase-4 inhibitors in Japanese patients with type 2 diabetes might be associated with a diplotype of two single nucleotide polymorphisms on the interleukin-6 promoter region under a certain level of physical activity

Aims/Introduction

Muscle-derived interleukin-6 (IL-6) has been reported to promote glucagon-like peptide-1 (GLP-1) secretion, and we explored the association of single nucleotide polymorphisms (SNPs) in the human IL-6 promoter region with the responsiveness to dipeptidyl peptidase-4 inhibitors (DPP-4Is), drugs that increase circulating GLP-1.

Materials and Methods

The present observational study enrolled Japanese patients with type 2 diabetes who took a DPP-4I over 3 months, and most of the clinical information was collected retrospectively. We defined non-responders as those having less than a 0.2% decrease of the glycated hemoglobin level at 3 or 4 months after starting DPP-4I treatment. Physical activity was retrospectively estimated by the Japanese short version of International Physical Activity Questionnaire.

Results

We studied 316 patients whose physical activity corresponding to the season of the DPP-4I administration was estimated. The non-responder rate was 29.7%. We analyzed rs1800796 and rs2097677, both are suggested to be functional in Japanese. Multivariate analysis for all patients showed that the adjusted odds ratio for the non-responder risk of the diplotype rs1800796 G/*–rs2097677 A/* against C/C-G/G (OR_G*A*) was 0.445 (P = 0.068). When patients were stratified by the International Physical Activity Questionnaire into low (n = 149) and moderate/high (n = 167) activity groups, however, OR_G*A* in each group was 1.58 (P = 0.615) and 0.153 (P = 0.003), respectively.

Conclusions

The diplotype rs1800796 G/*–rs2097677 A/* might contribute to responsiveness to DPP-4Is in Japanese patients with type 2 diabetes under a certain level of physical activity. However, further investigation is warranted to confirm this.

Relationships between genetic polymorphisms in inflammation-related factor gene and the pathogenesis of nasopharyngeal cancer

Our study aims to discuss the association between inflammation-related factors such as single nucleotide polymorphisms (SNPs) with susceptibility and recurrence in nasopharyngeal carcinoma. We used Taqman real-time polymerase chain reaction (PCR) to characterize the genetic variation of five SNPs in 194 nasopharyngeal carcinoma patients and 231 healthy subjects. All statistical analysis is performed with statistical product and service solutions v13.0; odds ratio (OR) value and 95 % confidence interval (CI) were calculated. There is no relationship between TGFβ1 -869 T/C, IL-6 -634C/G, TGFβ1 -509C/T, IL1 -511C/T and nasopharyngeal carcinoma susceptibility. Both single factor and multiple factors analysis showed that IL1a -889 T/T genotype is significantly associated with nasopharyngeal carcinoma in decreasing the risk of nasopharyngeal carcinoma. A highly significant association was found between IL1a -889 T/T genotype and protective genotype as defined by various pathological types. This is more obvious in the protective genotype of the non-keratin-type squamous carcinoma undifferentiated type. We also discovered that genotype G/G and C/G + G/G of IL6 -634 gene are associated with reduced recurrence of nasopharyngeal carcinoma. IL1a -889 gene polymorphism and susceptibility is related to nasopharyngeal carcinoma and can potentially decrease the risk of nasopharyngeal carcinoma in the Han Chinese population in north China. IL1-889 TT genotype is protective genotype for nasopharyngeal carcinoma. We have provided evidence that the GG genotype of the IL6 -634 gene is associated with recurrent risk of nasopharyngeal carcinoma. The G allele is the protective gene of nasopharyngeal carcinoma recurrence.

Interleukin-6 level and gene polymorphism in spontaneous miscarriage

The aetiology of spontaneous miscarriage, the most common pregnancy complication, remains undefined. One of postulated factors involved in miscarriage pathology is interleukin 6 (IL-6). Therefore, the aim of the study was to evaluate IL-6 and interleukin 6 receptor (IL-6R) gene polymorphisms in patients with spontaneous miscarriage. One hundred fifty-seven patients diagnosed with spontaneous miscarriage and age and gestational time matched controls were included in the case-control study. In all study participants circulating IL-6 levels (chemiluminescent immunoassay) and IL6-174G>C as well as IL6R rs2228145:A>C polymorphisms were evaluated. The distribution of IL6 as well as IL6R alleles and genotypes were similar in the controls and patients with miscarriage. Only a trend of more frequent appearance of -174GC+CC and C allele in the patients with miscarriage was noted. Blood serum concentrations of IL-6 were significantly elevated in patients with miscarriage vs those with physiological pregnancy. Likewise, IL-6 concentrations differ significantly with the types of miscarriage. The highest concentrations of the cytokine was seen in subjects with incomplete miscarriage (4.28 ± 4.88 pg/ml) followed by imminent miscarriage (2.97 ± 2.42 pg/ml), and then missed miscarriage (2.07 ± 1.90 pg/ml), being significantly the lowest in missed miscarriage group. No association between the IL6 genotype and IL-6 serum concentration were noted, both in the miscarriage group and in the control group. The findings of the study support the role of IL-6 in spontaneous miscarriage irrespectively of its type. However, no correlation between circulating IL-6 and IL6 gene polymorphism, as well as IL-6 and IL-6R polymorphisms associations with spontaneous miscarriage were revealed.

Interleukin-6 -634C/G polymorphism is associated with lung cancer risk: a meta-analysis

Several studies have examined the associations of polymorphisms in interleukin-6 (IL6) with lung cancer (LC) risk. However, the results were conflicting. Thus, a meta-analysis was conducted to determine the relationship between IL6 polymorphisms and LC risk. Databases including PubMed, EMBASE, Wanfang, and China National Knowledge Infrastructure (CNKI) were searched. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Thirteen studies were included in this meta-analysis. Overall, a significant association between IL6 -634C/G polymorphism and LC susceptibility was observed for GG + CG vs. CC (OR = 1.33, 95% CI 1.20-1.47, P < 0.00001). This polymorphism was also significantly associated with LC risk in Asians (OR = 1.33, 95% CI 1.20-1.47, P < 0.00001), female patients (OR = 1.30, 95% CI 1.11-1.52, P = 0.0009), male patients (OR = 1.25, 95% CI 1.03-1.52, P = 0.02), non-small cell lung cancer patients (OR = 1.21, 95% CI 1.03-1.41, P = 0.02), small cell lung cancer patients (OR = 1.91, 95% CI 1.23-2.97, P = 0.004), smokers (OR = 1.42, 95% CI 1.21-1.65, P < 0.0001), and non-smokers (OR = 1.32, 95% CI 1.13-1.53, P = 0.0003), respectively. No significant result was found for IL6 -174C/G polymorphism. This meta-analysis suggested that IL6 -634C/G polymorphism was a risk factor for LC.

The association of the 174G>C polymorphism of interleukin 6 gene with diabetic nephropathy in patients with type 2 diabetes mellitus

AIMS

To evaluate the association of 174G>C polymorphism on interleukin-6 (IL-6) gene with diabetic nephropathy in patients with type 2 diabetes.

METHODS

A total of 393 Greek subjects with type 2 diabetes (mean age 66.5±10.0years, men n=203, women n=190) were examined. Diabetic nephropathy was defined as presence of microalbuminuria and/or proteinuria. The IL-6 174G>C polymorphism was detected by polymerase chain reaction and appropriate restriction enzyme digestion. High sensitivity C-reactive protein was assayed by particle-enhanced immunonephelometry.

RESULTS

The genotype distribution (%) was GG: 49.1, GC: 26.8 and CC: 24.1, with no gender difference. The CC homozygotes had lower albumin excretion (mg/24h) in comparison with the GC genotype [CC: 8.9 (4.0-20.9) vs GC: 21.95 (9.1-53.35), P=0.004]. Participants with the GC genotype tended to have more frequently nephropathy than those with the GG or the CC genotype [GC: 44.55% vs GG: 35.1% and CC: 28.3%, P=0.07)]. The CC homozygotes in comparison with GC heterozygotes had lower odds to have nephropathy (odds ratio: 0.51, 95% confidence intervals=0.28-0.91, P=0.02), even after adjustment for sex, age, duration of diabetes, body mass index, smoking, hypertension, lipids and glycated hemoglobin, (P=0.01).

CONCLUSION

In type 2 diabetes states, CC homozygotes have lower albumin excretion and are protected from nephropathy in comparison with GC genotypes.

Association of interleukin-6 -174 G>C promoter polymorphism with increased risk of type 2 diabetes mellitus patients with diabetic nephropathy in Turkey

OBJECTIVE

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus. We aimed to evaluate the interleukin (IL)-6 gene polymorphisms in type 2 DN and control subjects.

MATERIALS AND METHODS

The patients selected from the Department of Endocrinology and Metabolism Diseases included 43 type 2 diabetes mellitus patients without DN and 43 type 2 diabetes mellitus patients with DN and 340 healthy normal controls. All subjects underwent venous blood drawing for complete hormonal assays, lipid profile, glucose, and insulin and Il-6 gene polymorphism genetic analysis.

RESULTS

IL-6 -174 G>C genotype distribution was different between the control group and the type 2 diabetes mellitus patients (p=0.004). The higher frequency of the polymorphic G allele was also similar for the group with type 2 diabetes mellitus as for the control group. The frequency of the polymorphic G allele was 83.9% in diabetic patients with nephropathy versus 70.9% in those without nephropathy (p=0.039).

CONCLUSION

We suggest that the -174 G>C polymorphism of the IL-6 gene is an independent risk factor for DN in Turkish type 2 diabetes mellitus patients.

Association between interleukin-6 gene polymorphisms and bone mineral density: a meta-analysis

BACKGROUND

Many studies have examined the association between interleukin-6 (IL-6) gene polymorphisms and bone mineral density (BMD). However, the results remain conflicting. To assess the relationship more precisely, a meta-analysis was performed.

METHODS

The PubMed, Embase, Chinese BioMedical Literature (CBM), Wanfang, and China National Knowledge Infrastructure (CNKI) database were searched for relevant articles published up to March 2013. Weighted mean difference (WMD) and 95% confidence interval (95% CI) were calculated using a fixed-effects or random-effects model.

RESULTS

A total of 16 articles with 11,957 subjects were investigated in this meta-analysis. Overall, -634C/G polymorphism was significantly associated with BMD at the femoral neck (WMD, -0.016 g/cm(2); 95% CI, -0.028 to -0.003 g/cm(2)), lumbar spine (WMD, -0.049 g/cm(2); 95% CI, -0.069 to -0.030 g/cm(2)), and whole body (WMD, -0.023 g/cm(2); 95% CI, -0.037 to -0.009 g/cm(2)) for GG versus CC+CG. In subgroup analyses stratified by ethnicity, individuals carrying -634GG genotype had a significantly lower mean BMD at any skeletal site examined, compared with individuals with -634CC or -634CG genotype in Asian populations. For -174G/C polymorphism, the BMD differences between CC+CG and GG genotype were 0.004 g/cm(2) at the distal radius (95% CI, 0.004 to 0.005 g/cm(2)), 0.011 g/cm(2) at the trochanter (95% CI, 0.002 to 0.020 g/cm(2)), and 0.017 g/cm(2) at the Ward's triangle (95% CI, 0.003 to 0.032 g/cm(2)). No significant publication bias was observed in either the -634C/G or -174G/C polymorphism.

CONCLUSIONS

This suggests that there are modest effects of the -634C/G and -174G/C polymorphisms on BMD. Large-scale and well-designed studies are required to further investigate gene-gene and gene-environment interactions on IL-6 polymorphisms and BMD in various populations.

The linkage between inflammation and Type 2 diabetes mellitus

The Type 2 diabetes mellitus (DM2) is considered nowadays as one of the most important chronic disturbances because of the significant number of people with diabetes and its severe complications, responsible for elevated indexes of morbidity and mortality. DM2 is characterized by several degrees of insulin resistance and relative deficiency in its secretion. Genetic and environmental factors have been described as of major importance in the DM2 development as obesity, which is directly correlated with development of resistance in peripheral tissues and inflammatory state in metabolic activated adipose tissue. Inflammatory responses may have a dual role in DM2, since it may have either a causal relationship leading to resistance to insulin or may be intensified by the hyperglycemic state, resulting in DM2 complications. In this review, we discuss the association of polymorphisms in genes encoding inflammatory cytokines and the increased level of these pro-inflammatory markers, associated to chronic pathologic conditions in DM2.

Association between the interleukin-6 gene -572 C/G polymorphism and the risk of type 2 diabetes mellitus: a meta-analysis of 11,681 subjects

The association between the interleukin-6 (IL-6) gene -572 C/G (rs1800796) polymorphism and type 2 diabetes mellitus (T2DM) risk remains controversial. Thus, we performed this meta-analysis by searching PubMed, Embase, Web of Science, CBMdisc and CNKI databases until January 30, 2012. In addition, hand searching of the references of identified articles was performed. A total of 10 case-control studies including 11,681 subjects were selected to evaluate the possible association. Our results showed evidence for significant association between the IL-6 gene -572 C/G polymorphism and T2DM risk (for G allele vs. C allele: odds ratio [OR] = 1.29, 95% confidence interval [CI] = 1.09-1.52, P = 0.002, P = 0.008 after Bonferroni testing; for G/G vs. C/C: OR = 1.89, 95% CI = 1.51-2.37, P < 0.00001, P < 0.00004 after Bonferroni testing; for GG vs. G/C + C/C: OR = 1.75, 95% CI = 1.20-2.56, P = 0.004, P = 0.016 after Bonferroni testing; for G/G + G/C vs. C/C: OR = 1.32, 95% CI = 1.11-1.57, P = 0.001, P = 0.004 after Bonferroni testing). In addition, similar results were obtained in the subgroup analysis based on ethnicity. In summary, the present meta-analysis suggests a significant association between the IL-6 gene -572 G allele and increased risk of T2DM.

A two-SNP IL-6 promoter haplotype is associated with increased lung cancer risk

BACKGROUND

Aberrant expression of interleukin-6 (IL-6) may play an important role in lung carcinogenesis. Whether IL-6 promoter haplotypes are associated with lung cancer risk and their functions have not yet been studied. We tested the hypothesis that single-nucleotide polymorphism (SNP) and/or haplotypes of IL-6 promoter are associated with risk of lung cancer.

METHODS

Two functional IL-6 promoter SNPs (-6331T>C and -572C>G) were genotyped in the discovery group including 622 patients and 614 controls, and the results were replicated in an independent validation group including 615 patients and 638 controls. Luciferase reporter gene assays were conducted to examine the function of IL-6 promoter haplotypes.

RESULTS

None of the functional IL-6 promoter SNPs were associated with lung cancer risk in either study. However, a two-SNP CC (-6331C and -572C) IL-6 promoter haplotype was significantly more common among cases than among controls in both groups (P = 0.031 and P = 0.035, respectively), indicating that this haplotype is associated with increased lung cancer risk {adjusted odds ratio [OR], 1.56 [95 % confidence interval (95 % CI), 1.04-2.34] and 1.51 [95 % CI, 1.03-2.22], respectively}. Combined analysis of both studies showed a strong association of this two-SNP haplotype with increased lung cancer risk (adjusted OR, 1.53; 95 % CI, 1.16-2.03; P = 0.003). Comparably, luciferase reporter assays of A549 lung cancer cell lines transfected with the CC haplotype revealed that the two-SNP haplotype had significantly higher IL-6 transcriptional activity compared with cells transfected with the common haplotype.

CONCLUSIONS

This is the first evidence of identifying an IL-6 promoter haplotype (CC) associated with increased risk of lung cancer.

Interleukin-6 -634 C/G and -174 G/C polymorphisms in Korean patients undergoing hemodialysis

BACKGROUND/AIMS

Chronic inflammatory status is a possible risk factor for vascular access dysfunction in hemodialysis (HD) patients, but susceptibility differences appear among individuals. Interleukin (IL)-6 is a well-known inflammatory cytokine with various polymorphisms. We examined whether IL-6 polymorphisms are associated with vascular access dysfunction in HD patients.

METHODS

A total of 80 HD patients (including 42 diabetic patients) were enrolled. Polymorphisms in the IL-6 gene promoter (-634 C/G and -174 G/C) were studied using restriction length polymorphism polymerase chain reaction analysis. Vascular access patency was compared between the patient groups with respect to IL-6 polymorphisms. An additional 89 healthy individuals were enrolled in the control group. Plasma IL-6 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

The GG genotype and G allele at position -634 in the IL-6 promoter were more frequently observed in HD patients than in controls. Furthermore, the distribution of the -634 polymorphism differed according to vascular access patency in non-diabetic HD patients. However, the G allele was not a significant risk factor for early access failure. No significant association appeared between the IL-6 -634 C/G polymorphism and plasma IL-6 levels. The C allele of the IL-6 -174 G/C polymorphism was not detected in our study population.

CONCLUSIONS

The IL-6 -634 G allele appears with greater frequently in patients with end-stage renal disease and may be associated with vascular access dysfunction in non-diabetic HD patients.

Interleukin-6 promoter polymorphisms and susceptibility to atrial fibrillation in elderly Han Chinese patients with essential hypertension

There is an accumulating body of evidence indicating a strong association between inflammation and the pathogenesis of atrial fibrillation (AF). Interleukin-6 (IL-6) is a pleiotropic cytokine, functions as a mediator of inflammatory response, and has both proinflammatory and anti-inflammatory properties. The aim of the present study was to investigate the association of the -634C/G polymorphism of the IL-6 gene with AF in elderly Han Chinese patients with essential hypertension (EH). A total of 169 elderly patients with EH were eligible for this study. Patients with AF (n=75) were allocated to the AF group, and 94 subjects without AF to the control group. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotype frequencies. The distribution of the IL-6 -634C/G genotypes (CC, CG, and GG) was 67.02%, 30.85%, and 2.13% in the controls, and 50.67%, 40.00%, and 9.33% in AF subjects, respectively (P=0.0312). The frequency of the G allele in the AF group was significantly higher than that in the control group (29.33% vs. 17.55%, P=0.0103). Compared with the CC and CG genotypes, the GG homozygote had a 4.7353-fold increased risk of AF [95% confidence interval (CI)=0.9537-23.5116, P=0.0382]. These findings suggest that the IL-6 -634C/G polymorphism is associated with AF, and the G allele has increased risk of AF in elderly Han Chinese patients with EH.

The Association of Interleukin 6−634C/G Polymorphism With Left Atrial Thrombus and Severe Spontaneous Echocontrast in Patients With Atrial Fibrillation

Atrial fibrillation (AF) not only is an independent risk factor for death but also confers significant risk of morbidity from stroke associated with left atrial thrombus. The association of interleukin 6 ( IL-6) polymorphism with thrombus in AF has not been investigated before. We carried out a case–control study in Han Chinese. The IL-6 −634C/G genotypes of 31 patients with thrombus and 45 patients without thrombus were detected by polymerase chain reaction and restriction fragment length polymorphism. The frequencies of the IL-6 genotypes (CC, CG, and GG) were 29.03%, 54.54%, and 16.13% for the patients with thrombus, and 55.56%, 40.00%, and 4.44% for the patients without thrombus, respectively ( P = .0391). Compared with the CC genotype, the G allele carriers (CG + GG) had a 2.79-fold increased risk of thrombus or severe spontaneous echocontrast (SEC). These results suggest that IL-6 −634C/G polymorphism is associated with thrombus and severe SEC, and the G allele is an independent risk for thrombus and severe SEC in Han Chinese patients with AF.

Interleukin-6 gene (IL-6): a possible role in brain morphology in the healthy adult brain

Background

Cytokines such as interleukin 6 (IL-6) have been implicated in dual functions in neuropsychiatric disorders. Little is known about the genetic predisposition to neurodegenerative and neuroproliferative properties of cytokine genes. In this study the potential dual role of several IL-6 polymorphisms in brain morphology is investigated.

Methodology

In a large sample of healthy individuals (N = 303), associations between genetic variants of IL-6 (rs1800795; rs1800796, rs2069833, rs2069840) and brain volume (gray matter volume) were analyzed using voxel-based morphometry (VBM). Selection of single nucleotide polymorphisms (SNPs) followed a tagging SNP approach (e.g., Stampa algorigthm), yielding a capture 97.08% of the variation in the IL-6 gene using four tagging SNPs.

Principal findings/results

In a whole-brain analysis, the polymorphism rs1800795 (−174 C/G) showed a strong main effect of genotype (43 CC vs. 150 CG vs. 100 GG; x = 24, y = −10, z = −15; F(2,286) = 8.54, p_uncorrected = 0.0002; p_{AlphaSim-corrected} = 0.002; cluster size k = 577) within the right hippocampus head. Homozygous carriers of the G-allele had significantly larger hippocampus gray matter volumes compared to heterozygous subjects. None of the other investigated SNPs showed a significant association with grey matter volume in whole-brain analyses.

Conclusions/significance

These findings suggest a possible neuroprotective role of the G-allele of the SNP rs1800795 on hippocampal volumes. Studies on the role of this SNP in psychiatric populations and especially in those with an affected hippocampus (e.g., by maltreatment, stress) are warranted.

Cytokines in diabetic nephropathy

Diabetic nephropathy (DN), the most common cause of end-stage renal disease (ESRD), is increasingly considered an inflammatory process characterized by leukocyte infiltration at every stage of renal involvement. Cytokines act as pleiotropic polypeptides that regulate inflammatory and immune responses, providing important signals in the pathologic and physiologic processes. Inflammation and activation of the immune system are closely involved in the pathogenesis of diabetes and its microvascular complications. Proinflammatory, Th1, Th2, and Th17 cytokines, as well as TGF-beta, all take part in the development and progression of DN. Gene polymorphism of cytokines and their receptors may have functional variations and can be applied to predict the susceptibility and progression to DN. Improved knowledge on recognizing cytokines as significant pathogenic mediators in DN leaves opens the possibility of new potential therapeutic agents for future clinical treatments.

Association of IL-1β and IL-6 gene polymorphisms with recurrent spontaneous abortion in a Chinese Han population

As certain cytokines may play a role in unexplained recurrent spontaneous abortion (RSA) and also some cytokine gene polymorphisms may affect the level of cytokine production, the aim of this study was to investigate the relationship between Chinese RSA and polymorphisms of the genes coding for interleukin (IL)-1β (-31C/T, -511C/T, +3954C/T) and IL-6 (-634C/G). Women (n = 162) with at least three consecutive spontaneous abortions and 156 ethnically matched healthy women with at least one successful pregnancy were included. Genotypes were determined using restriction fragment length polymorphism analysis of polymerase chain reaction products. No significant differences were found in the IL-1β-31T, -511T and +3954T distributions between the RSA group and the control group. On the other hand, the frequencies of the IL-6-634GG genotype and -634G allele were significantly decreased in the RSA group versus the control group (genotype: P = 0.0003; allele: P = 0.002), suggesting the IL-6-634C/G polymorphism might be a possible genetic protective factor for RSA.

Polymorphisms in interleukin-6-6331 influences the susceptibility of a Chinese population to gastric cancer

We investigated the association of Interleukin (IL)-6-6331 polymorphisms with susceptibility to gastric cancer in 375 patients with gastric cancer and 386 age- and gender-matched healthy controls. After adjustment for the potential confounding effects of gender and age, IL-6-6331TC genotype was associated with a decreased risk of gastric cancer compared with the CC genotype. Further stratification analyses indicated that the protective effect of TC genotype was also observed in poorly differentiated gastric cancer, noncardia gastric cancer, and intestinal-type gastric cancer, respectively. These results suggest that the IL-6-6331 polymorphism is involved in susceptibility to developing gastric cancer.

The endothelial dysfunction in patients with type 2 diabetes mellitus is associated with IL-6 gene promoter polymorphism in Chinese population

The purpose of this study is to examine the effects of IL-6 gene promoter -174G/C and -572G/C polymorphism on endothelial function of Chinese T2DM and normal glucose regulation (NGR) subjects. 512 newly diagnosed T2DM patients and 483 NGR subjects were recruited and Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) was performed for the IL-6 gene promoter -174G/C and -572G/C polymorphism. Flow-mediated dilation (FMD) was measured as a non-invasive indicator for endothelial function. The results show that the C allele and CC genotype at -174 of IL-6 gene promoter region was extremely rare in both T2DM and NGR groups; genotypes' and alleles' frequency at -572 of IL-6 gene promoter region is of no difference between T2DM and NGR groups; within T2DM group, higher plasma IL-6 concentration and lower FMD was found in patients with -572 GC (2.36 ± 0.69, 4.23 ± 3.82%) or GG (2.32 ± 0.74, 4.24 ± 3.67%) genotype, compared with patients with CC (2.15 ± 0.62, 5.28 ± 3.94%) genotype. The conclusion of the study is that in comparison with patients of CC genotype, the T2DM patients of -572 GC or GG genotype may have more aggravated endothelial dysfunction (ED) and be at higher risk for coronary artery disease (CAD).

Molecular cloning, promoter analysis, SNP detection of Clusterin gene and their associations with mastitis in Chinese Holstein cows

To examine the effect of Clusterin (CLU) on mastitis, genetic association analysis was applied on mastitis and milk production traits of 1,137 Chinese Holstein cows. We detected two novel single nucleotide polymorphisms (SNPs), G+15781A in the seventh exon and C-994T before 5'-upstream region (UTR) of CLU gene, found five TATA box, one CpG island and more transcription factor binding sites in promoter region, respectively, Milk fat rate in genotype AA was significantly higher than in GG on fat rate (P < 0.01), milk fat and milk yield in combined haplotype H1H4 (AGCT) were significantly higher than in H3H4 (GGCT) (P < 0.05), H1H4 was decided advantage in nine milk production traits. Quadruplet cows in G+15781A were decided advantage in each milk production traits that 305-day milk yield, fat rate, protein rate and somatic cell scores (SCS) increased following with birth order. A allele and T allele had positive effect on SCS. In conclusion, this study showed that the haplotype AA may be a genetic marker on mastitis and other performance for Chinese Holstein cows.

Polymorphism of proinflammatory cytokine genes and albuminuria in the Japanese general population: the Takahata study

BACKGROUND

A cluster of proinflammatory cytokines plays an important role in the development of various renal diseases, and the expression of these cytokines is genetically modified. To examine the association between polymorphisms of proinflammatory cytokine genes and albuminuria, a cross-sectional study was conducted in the general population.

METHODS

Single nucleotide polymorphisms (SNPs) in six proinflammatory cytokine genes, including interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, CC chemokine ligand 1 (CCL1) and monocyte chemoattractant protein-1 (MCP-1), were genotyped in 2927 Japanese subjects. Urine albumin-creatinine ratio (UACR) was measured in morning spot urine samples.

RESULTS

Albuminuria (UACR ≥ 30 mg/g) was significantly associated with the A/A + A/G genotype at rs2069852 in the IL-6 gene (P = 0.01) and the A/A genotype at rs228269 in the CCL1 gene (P = 0.002). Multivariate analysis with adjustment for traditional risk factors showed that these genotypes independently predicted albuminuria [odds ratio (OR) 1.782, 95% confidence interval (CI) 1.171-2.712, P = 0.007 for the A/A + A/G genotype at rs2069852 in IL-6, and OR 1.432, 95% CI 1.128-1.770, P = 0.003 for the A/A genotype at rs228269 in CCL1]. The prevalence of albuminuria and the UACR were increased along with the increase of risk genotypes.

CONCLUSIONS

This study revealed that SNPs in the IL-6 and CCL1 genes were associated with albuminuria, and the combination of these genotypes had an additive effect on the prevalence and severity of albuminuria. This indicates that genetic factors influencing inflammatory responses may affect the development of renal injury in the Japanese general population.

A genetic variant near the equine interleukin 6 gene associated with copper:zinc ratio

The aim of this study was to validate an A/T single nucleotide polymorphism (SNP) corresponding to a LINE2 sequence located ∼1.1kb downstream of the IL-6 gene (SNP BIEC2-911738) and to determine if this variant is correlated with interleukin 6 (IL-6) modulation or with different plasma concentrations of Zn, Cu, Se and Fe. The frequency of the newly described variant T ranged from 0 to 23.1% among different breeds of horses. SBIEC2-911738 was not associated with changes in IL-6 plasma levels. Increased Cu:Zn ratios were observed in horses carrying the AT genotype independently of breed when stabled for 24h after physical exercise.

Polymorphisms in inflammatory pathway genes, host factors and lung cancer risk in Chinese female never-smokers

Inflammation appears to be important in lung carcinogenesis among smokers, but its role among never-smokers is not well established. We hypothesized that inflammatory medical conditions and gene polymorphisms interact to increase lung cancer risk in never-smokers. We interviewed 433 Singaporean female never-smoker lung cancer patients and 1375 hospital controls, and evaluated six polymorphisms in the interleukin 1-β, interleukin 6 (IL6), cyclooxygenase-2, peroxisome proliferator-activated receptor-γ and interleukin 1-β receptor antagonist (IL1RN) genes. Tuberculosis was associated with a non-significant elevated risk of lung cancer [odds ratio (OR) 1.58, 95% confidence interval (CI) 0.95-2.62]. There was no effect of asthma, atopy or chronic productive cough individually. However, the presence of one or more of these conditions (asthma, cough or atopy) increased risk (OR 2.24, 95%CI 1.15-4.38) in individuals possessing the T/T genotype at interleukin 1-β -31T/C, but not in those possessing the C/T (OR 0.87, 95%CI 0.51-1.57) or C/C genotypes (OR 0.58, 95%CI 0.27-1.27), and in individuals having the *2 variable number of tandem repeat allele of IL1RN [OR 5.09 (1.39-18.67)], but not in those without (OR 0.93, 95%CI 0.63-1.35). The IL6-634 G allele increased the risk of lung cancer (OR 1.44, 95%CI 1.07-1.94). Lung cancer risk also increased with the number of polymorphism sites where at least 1 'risk' allele was present [interleukin 1-β -31T/C (T allele), IL1RN (*2 allele) and IL6-634C/G (G allele)] among those with asthma, cough or atopy (Ptrend 0.001) but not in those without (Ptrend 0.47). Our results suggest that the effect of inflammatory medical conditions on lung cancer in never-smokers is modulated by host genetic susceptibility and will need to be confirmed in other studies conducted in similar populations.