Effects of 174 G/C polymorphism in the promoter region of the interleukin-6 gene on plasma IL-6 levels and muscle strength in elderly women

The Role of IL-6 in Neurodegenerative Disorders

"Neurodegenerative disorder" is an umbrella term for a group of fatal progressive neurological illnesses characterized by neuronal loss and inflammation. Interleukin-6 (IL-6), a pleiotropic cytokine, significantly affects the activities of nerve cells and plays a pivotal role in neuroinflammation. Furthermore, as high levels of IL-6 have been frequently observed in association with several neurodegenerative disorders, it may potentially be used as a biomarker for the progression and prognosis of these diseases. This review summarizes the production and function of IL-6 as well as its downstream signaling pathways. Moreover, we make a comprehensive review on the roles of IL-6 in neurodegenerative disorders and its potential clinical application.

Impacts of pro-inflammatory cytokines variant on cardiometabolic profile and premature coronary artery disease: A systematic review and meta-analysis

Interleukin-6 (IL-6), a pivotal pro-inflammatory cytokine, is closely linked to vascular wall thickening and atherosclerotic lesion. Since serum IL-6 levels are largely determined by the genetic variant in IL-6, this study was conducted to investigate whether the IL-6 variant impacts cardiometabolic profile and the risk of premature coronary artery disease (PCAD). PubMed, Cochrane Library, Central, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and ClinicalTrials.gov were searched from May 13, 2022 to June 28, 2023. In total, 40 studies (26,543 individuals) were included for the analysis. The rs1800795 (a function variant in the IL-6 gene) C allele was linked to higher levels of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), fasting plasma glucose (FPG), body mass index (BMI), and waist circumference (WC), and a lower levels of high-density lipoprotein cholesterol (HDL-C). However, no significant association was observed of rs1800795 with triglycerides (TG), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Interestingly, a significant association was detected between rs1800795 and PCAD. Subgroup analyses indicted that the impacts of rs1800795 on cardiometabolic risk factors were significant in Caucasians but stronger in obese patients. In contrast, the impact of rs1800795 on PCAD was significant in brown race population. In summary, rs1800795 had a slight but significant impact on cardiometabolic risk factors and PCAD. IL-6 inhibition with ziltivekimab or canakinumab may benefit high-risk populations (e.g. brown race population, Caucasians, obese patients, etc.) with rs1800795 to prevent PCAD.

IL6 genetic variants haplotype is associated with susceptibility and disease activity but not with therapy response in patients with inflammatory bowel disease

PURPOSE

The aim of the present study was to evaluate the IL6 -174 G>C (rs1800795) and -572 G>C (rs1800796) genetic variants and their association with inflammatory bowel diseases (IBDs), disease activity, and response to TNF-α inhibitors.

METHODS

The study included 178 patients with IBD and 224 healthy controls. Among the IBD patients, 66 of them were in use of TNF-α inhibitors therapy and were followed during 48 weeks and categorized as responders and non-responders.

RESULTS

In total, 89 (50.0%) had ulcerative colitis (UC) and 89 (50.0%) had Crohn's disease (CD). The IL6 -572 CC genotype presented a protective effect in CD patients in codominant and recessive models, while the IL6 -174 CC genotype was associated with susceptibility to UC and CD. The presence of G/C haplotype in the recessive model (GCGC) was associated with UC. The Crohn's disease endoscopic index of severity was low in those patients carrying the GCGC haplotype. It was observed that there was no association between the IL6 genetic variants and TNF-α inhibitor therapy response.

CONCLUSION

The G/C haplotype (recessive model) was associated with susceptibility to UC but not to CD. However, the G/C haplotype (dominant model) was associated with the endoscopic activity of CD. Moreover, these IL6 variants did not predict the TNF-α inhibitor therapy response.

Methodological Approach of the Iron and Muscular Damage: Female Metabolism and Menstrual Cycle during Exercise Project (IronFEMME Study)

Abstract

Background: The increase in exercise levels in the last few years among professional and recreational female athletes has led to an increased scientific interest about sports health and performance in the female athlete population. The purpose of the IronFEMME Study described in this protocol article is to determine the influence of different hormonal profiles on iron metabolism in response to endurance exercise, and the main markers of muscle damage in response to resistance exercise; both in eumenorrheic, oral contraceptive (OC) users and postmenopausal well-trained women. Methods: This project is an observational controlled randomized counterbalanced study. One hundered and four (104) active and healthy women were selected to participate in the IronFEMME Study, 57 of which were eumenorrheic, 31 OC users and 16 postmenopausal. The project consisted of two sections carried out at the same time: iron metabolism (study I) and muscle damage (study II). For the study I, the exercise protocol consisted of an interval running test (eight bouts of 3 min at 85% of the maximal aerobic speed), whereas the study II protocol was an eccentric-based resistance exercise protocol (10 sets of 10 repetitions of plate-loaded barbell parallel back squats at 60% of their one repetition maximum (1RM) with 2 min of recovery between sets). In both studies, eumenorrheic participants were evaluated at three specific moments of the menstrual cycle: early-follicular phase, late-follicular phase and mid-luteal phase; OC users performed the trial at two moments: withdrawal phase and active pill phase. Lastly, postmenopausal women were only tested once, since their hormonal status does not fluctuate. The three-step method was used to verify the menstrual cycle phase: calendar counting, blood test confirmation, and urine-based ovulation kits. Blood samples were obtained to measure sex hormones, iron metabolism parameters, and muscle damage related markers. Discussion: IronFEMME Study has been designed to increase the knowledge regarding the influence of sex hormones on some aspects of the exercise-related female physiology. Iron metabolism and exercise-induced muscle damage will be studied considering the different reproductive status present throughout well-trained females’ lifespan.

Trial registration

The study was registered at Clinicaltrials.gov NCT04458662 on 2 July 2020.

Associations between IL-6 Variations and Congenital Heart Disease Incidence among Chinese Han People

Background

Our research explored if Interleukin-6 (IL-6) variants held substantial connection to congenital heart disease (CHD) susceptibility among Chinese Han children.

Material/Methods

A total of 102 CHD children were recruited as the case group while 98 healthy persons were recruited as the control group. We used polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) completed genotyping for IL-6 variants rs1800795 and rs1800796. The Hardy-Weinberg equilibrium (HWE) among controls was tested using χ² analysis. Genotype and allele frequencies for variants were compared between groups. Odds ratio (OR) accompanied by 95% confidence interval (CI) reflected the potential link of IL-6 variants to CHD occurrence.

Results

A remarkable increased trend of rs1800795 CC genotype and C allele was detected in the CHD patient group (P<0.05). Individuals carrying rs1800795 CC genotype showed higher risk for CHD (OR=3.763, 95% CI=1.162–12.190). In addition, rs1800795 C allele could increase CHD incidence (OR=1.766, 95% CI=1.101–2.832). No significant differences were detected in IL-6 gene rs1800796 polymorphism in both genotype and allele distributions between the case group and the control group (P>0.05). These associations had no significant alteration after the adjustment of age, gender, maternal smoking history, and maternal history of diabetes.

Conclusions

IL-6 variant rs1800795 exhibited a close relation to CHD susceptibility among Chinese Han people while the mutant C allele promoted CHD incidence. But rs1800796 variant showed no such influence.

Regulation of interleukin 6 by a polymorphic CpG within the frontal cortex in Alzheimer's disease

The cytokine interleukin 6 (IL-6) has been linked to the pathogenesis of Alzheimer's disease (AD). This is the first study to investigate the genetic and epigenetic interactions in the control of IL-6 in human brain and its relation to AD neuropathology in prefrontal cortex tissues from AD and controls genotyped for the SNP -174 C/G rs1800795, a polymorphic CpG in which the G allele creates a CpG site. Within CC homozygotes there were significantly higher brain levels of IL-6 protein compared to G allele carriers. The C allele that resulted in an absence of methylation at a CpG was also associated with significant changes in methylation at neighboring CpGs. Furthermore, there were significant differences in methylation between CC and CG/GG at CpG sites in the AD and control groups. That DNA methylation was altered in the brains by the presence of rs1800795, which further correlated with protein levels suggests the presence of a polymorphic CpG and genetic-epigenetic interactions in the regulation of IL-6 in the prefrontal cortex within AD brains.

THE EFFECT OF MUSCLE DAMAGE AND THE IL-6-174C/G POLYMORPHISM ON THE SERUM IL-6 LEVELS OF OLDER MEN

ABSTRACT Introduction Fast population aging is a global reality. Today’s major challenge is to promote the healthy aging of more and more people by acting on factors that can be modified, such as physical exercise. Regular exercise could contribute to the prevention of chronic diseases associated with aging. Research has been conducted on the physical training response of elderly individuals, but there is not yet any consensus on the influence of strength training or IL-6 polymorphism on levels of inflammatory markers such as IL-6 and muscle damage marker CK, particularly in healthy elderly male individuals. Objectives The aim of this study was to evaluate the relationship of IL-6 promoter -174 C/G gene polymorphism on systemic IL-6 responses and muscle damage after eccentric strength training in elderly men. Methods This is a prospective, high-quality study. Gene frequency of polymorphism of promoter gene IL6 G-174C was identified using the Hardy-Weinberg test in 28 older male volunteers. The relationships of each genotype with IL-6 and CK serum levels were analyzed. CK and IL-6 levels were determined at pre-training and 0h, 3h, 24h, and 48h post-training periods. Results Differences in baseline and post-training IL-6 levels of genotypic groups were observed for all time periods analyzed (p = 0.029). Eccentric exercise efficiently reduced post-intervention muscle damage, thus showing a statistical difference between the pre- and post-intervention time points ( p = <0.0005). Conclusion Eccentric training influenced CK and IL-6 modulation independently of the polymorphism of the IL-6 promoter gene -174 C/G. Level of evidence II, Prospective comparative type.

Racial Differences in Immunological Landscape Modifiers Contributing to Disparity in Prostate Cancer

Prostate cancer affects African Americans disproportionately by exhibiting greater incidence, rapid disease progression, and higher mortality when compared to their Caucasian counterparts. Additionally, standard treatment interventions do not achieve similar outcome in African Americans compared to Caucasian Americans, indicating differences in host factors contributing to racial disparity. African Americans have allelic variants and hyper-expression of genes that often lead to an immunosuppressive tumor microenvironment, possibly contributing to more aggressive tumors and poorer disease and therapeutic outcomes than Caucasians. In this review, we have discussed race-specific differences in external factors impacting internal milieu, which modify immunological topography as well as contribute to disparity in prostate cancer.

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.

Association between interleukin 6 -174 G/C promoter gene polymorphism and runners' responses to the dietary ingestion of antioxidant supplementation based on pequi (Caryocar brasiliense Camb.) oil: a before-after study

Exercise is a double-edged sword: when practiced in moderation, it increases the expression of antioxidant enzymes, but when practiced strenuously it causes oxidative stress and cell damage. In this context, polymorphisms in the interleukin (IL)-6 gene should be investigated better because they can influence performance, at least in exercise that generates oxidative stress and leads to muscular injuries with consequent inflammation. In this work, we investigated the influence of IL-6 -174 G/C polymorphism on tissue damage and inflammation markers, lipid peroxidation, hemogram and lipid profile of runners before and after ingestion of 400 mg of pequi oil in capsules supplied daily for 14 consecutive days. The IL-6 genotypes were associated with significant differences in lipid peroxidation, with the CC mutant having lower values. There were also significant differences among these genotypes in the response to supplementation with pequi oil, exercise-induced damage and C-reactive protein (CRP) levels. The best protection against damage was observed with the heterozygous genotype. Although the CC genotype showed an increase in CRP levels after supplementation, the lack of a positive correlation between triglycerides and high-sensitivity CRP in this mutant genotype after supplementation indicated a protective effect of pequi. These findings deserve further investigation, particularly with regard to the quantification of circulating IL-6 concentrations.

Genetic variation and exercise-induced muscle damage: implications for athletic performance, injury and ageing

Prolonged unaccustomed exercise involving muscle lengthening (eccentric) actions can result in ultrastructural muscle disruption, impaired excitation-contraction coupling, inflammation and muscle protein degradation. This process is associated with delayed onset muscle soreness and is referred to as exercise-induced muscle damage. Although a certain amount of muscle damage may be necessary for adaptation to occur, excessive damage or inadequate recovery from exercise-induced muscle damage can increase injury risk, particularly in older individuals, who experience more damage and require longer to recover from muscle damaging exercise than younger adults. Furthermore, it is apparent that inter-individual variation exists in the response to exercise-induced muscle damage, and there is evidence that genetic variability may play a key role. Although this area of research is in its infancy, certain gene variations, or polymorphisms have been associated with exercise-induced muscle damage (i.e. individuals with certain genotypes experience greater muscle damage, and require longer recovery, following strenuous exercise). These polymorphisms include ACTN3 (R577X, rs1815739), TNF (-308 G>A, rs1800629), IL6 (-174 G>C, rs1800795), and IGF2 (ApaI, 17200 G>A, rs680). Knowing how someone is likely to respond to a particular type of exercise could help coaches/practitioners individualise the exercise training of their athletes/patients, thus maximising recovery and adaptation, while reducing overload-associated injury risk. The purpose of this review is to provide a critical analysis of the literature concerning gene polymorphisms associated with exercise-induced muscle damage, both in young and older individuals, and to highlight the potential mechanisms underpinning these associations, thus providing a better understanding of exercise-induced muscle damage.

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.

Association between interleukin-6 polymorphisms and urinary system cancer risk: evidence from a meta-analysis

Background

Interleukin-6 (IL-6) is a multifunctional proinflammatory cytokine involved in cancer initiation and progression. Numerous studies have investigated the associations between IL-6 polymorphisms (IL-6 −174G>C, −592G>C, −597G>A) and risk of urinary system cancers, including prostate cancer, bladder cancer, and renal cell cancer. However, conclusions from these studies were controversial. Thus, we conducted the current meta-analysis to obtain the comprehensive profile regarding the association between IL-6 polymorphisms and urinary system cancer risk.

Methods

According to inclusion and exclusion criteria, the associations of IL-6 polymorphisms with urinary system cancer were searched from database and analyzed using STATA 12.0 statistical software. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations.

Results

A total of 20 previous publications consisting of 15,033 cases and 17,655 controls were involved in this meta-analysis. Significant association was observed in overall population regarding IL-6 −592G>C polymorphisms (G vs C: OR =0.1.30, 95% CI =1.13−2.52; GG vs CC: OR =1.81, 95% CI =1.31−2.52; GG vs GC + CC: OR =1.33, 95% CI =1.02−1.75; GG + GC vs CC: OR =1.41, 95% CI =1.09−1.83). In the stratified analyses by ethnicity, the significant associations were found among Asian (GG vs CC: OR =1.89, 95% CI =1.34−2.66; GG + GC vs CC: OR =1.43, 95% CI =1.09−1.87) and Black population (GC vs CC: OR =0.20, 95% CI =0.05−0.82) rather than Caucasian men. Likewise, there were noticeable associations in almost all the other subanalyses such as cancer types, control sources, genotyped methods, and sample sizes. However, no significant associations were identified between any of IL-6 −174G>C polymorphisms with urinary system cancer, except for Asian population (G vs C: OR =0.81, 95% CI =0.70−0.95; GG vs CC: OR =0.51, 95% CI =0.35−0.74; GC vs CC: OR =0.49, 95% CI =0.33−0.72; GG + GC vs CC: OR =0.50, 95% CI =0.35−0.72; respectively). In addition, no significant associations were detected between IL-6 −597G>A polymorphism and urinary system cancer, regardless of whole or subgroups.

Conclusion

This meta-analysis presents a relatively comprehensive view of the associations between IL-6 polymorphism and urinary system cancer risk to explore the carcinogenic mechanisms, which will help shed light on the clinical diagnosis and therapy for urinary system cancer. However, further detailed studies are needed to verify our conclusion.

The A allele of cluster of differentiation 36 (CD36) SNP 1761667 associates with decreased lipid taste perception in obese Tunisian women

Recent studies have suggested that excessive intake of dietary fat is associated with obesity. Some obese subjects have been reported to exhibit high thresholds for the gustatory detection of lipids via lipid receptors, such as cluster of differentiation 36 (CD36). We studied lingual detection thresholds for emulsions containing oleic acid in obese Tunisian women (n 203) using a three-alternative forced choice (3-AFC) method. Genotyping of the TNF-α (rs1800629), IL-6 (rs1800795) and CD36 (rs1761667) genes was performed to associate with lipid taste perception thresholds. The CD36 genotype distribution was as follows: GG (n 42), AG (n 102) and AA (n 59). Women with the CD36 GG genotype exhibited oral detection thresholds for oleic acid that were more than three times lower than those with the CD36 AA genotype. The present study confirms a high threshold of gustatory fat detection in obese women with the CD36 AA genotype, but there is no significant association with the IL-6 and TNF-α gene polymorphisms.

Meta-analysis of the correlation between IL-6 -174 G/C polymorphism and polycystic ovarian syndrome

AIM

The correlation between interleukin-6 (IL-6) gene polymorphism and polycystic ovary syndrome (PCOS) has been reported, but the conclusions are controversial. The present study was aimed to evaluate the association between IL-6 -174 G/C polymorphism and susceptibility of PCOS by meta-analysis.

MATERIAL AND METHODS

A systematic search on Medline, Embase, CNKI, Wanfang Data and VIP databases containing Chinese and English studies was conducted electronically using specific eligibility criteria. Meta-analysis was performed using Review Manager 5.2 software after Hardy-Weinberg equilibrium test. Effect sizes of odds ratio and 95% confidence interval (CI) were calculated and combined appropriately. To verify the reliability of the results, subgroup analyses and sensitivity analyses were performed.

RESULTS

Four selected studies containing 351 cases and 464 control participants were included. The pooled odds ratio between IL-6 -174 G/C polymorphism and susceptibility of PCOS under allele (C/G), dominant (CC+GC/GG) and recessive (CC/GG+GC) models were 0.63 (95%CI, 0.41-0.96), 0.53 (95%CI, 0.26-1.08) and 0.67 (95%CI, 0.39-1.16), respectively. The result under allele model was unstable in sensitivity analysis. Subgroup analysis showed that the correlation between IL-6 -174 G/C polymorphism and susceptibility of PCOS was not statistically significant in the studies that conformed to the Hardy-Weinberg equilibrium.

CONCLUSION

IL-6 -174 G/C polymorphism may be not related to susceptibility of PCOS. Nevertheless, further studies with large samples and studies considering other single-nucleotide polymorphisms of the IL-6 gene are needed to confirm our findings.

Relationship between Interleukin-6 gene polymorphism and hippocampal volume in antipsychotic-naïve schizophrenia: evidence for differential susceptibility?

Background

Various lines of evidence including epidemiological, genetic and foetal pathogenetic models suggest a compelling role for Interleukin-6 (IL-6) in the pathogenesis of schizophrenia. IL-6 mediated inflammatory response triggered by maternal infection or stress induces disruption of prenatal hippocampal development which might contribute towards psychopathology during adulthood. There is a substantial lack of knowledge on how genetic predisposition to elevated IL-6 expression effects hippocampal structure in schizophrenia patients. In this first-time study, we evaluated the relationship between functional polymorphism rs1800795 of IL-6 and hippocampal gray matter volume in antipsychotic-naïve schizophrenia patients in comparison with healthy controls.

Methodology

We examined antipsychotic-naïve schizophrenia patients [N = 28] in comparison with healthy controls [N = 37] group matched on age, sex and handedness. Using 3 Tesla – MRI, bilateral hippocampi were manually segmented by blinded raters with good inter-rater reliability using a valid method. Additionally, Voxel-based Morphometry (VBM) analysis was performed using hippocampal mask. The IL-6 level was measured in blood plasma using ELISA technique. SNP rs1800795 was genotyped using PCR and DNA sequencing. Psychotic symptoms were assessed using Scale for Assessment of Positive Symptoms and Scale for Assessment of Negative Symptoms.

Results

Schizophrenia patients had significantly deficient left and right hippocampal volumes after controlling for the potential confounding effects of age, sex and total brain volume. Plasma IL-6 levels were significantly higher in patients than controls. There was a significant diagnosis by rs1800795 genotype interaction involving both right and left hippocampal volumes. Interestingly, this effect was significant only in men but not in women.

Conclusion

Our first time observations suggest a significant relationship between IL-6 rs1800795 and reduced hippocampal volume in antipsychotic-naïve schizophrenia. Moreover, this relationship was antithetical in healthy controls and this effect was observed in men but not in women. Together, these observations support a “differential susceptibility” effect of rs1800795 in schizophrenia pathogenesis mediated through hippocampal volume deficit that is of possible neurodevelopmental origin.

Effects of resveratrol on the expression and DNA methylation of cytokine genes in diabetic rat aortas

This paper studies the expression of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, and IFN-γ and anti-inflammatory cytokines such as IL-10 in diabetic rat aortas, the effects of resveratrol on these cytokines, and the potential epigenetic mechanisms involved. The experiment was performed on rats divided into four groups: normal group (NC), normal interventional group (NB), diabetic group (DM), and diabetic interventional group (DB). The NB and DB groups were treated with resveratrol. After more than 3 months, the rats' aortas were removed and analyzed for cytokines by using immunohistochemistry, Western blotting, real-time PCR, and methylation-specific PCR. Histological localization of these cytokines was mainly found in the arterial intima of diabetic rats. The protein and mRNA expression levels of IL-1β, IL-6, TNF-α, and IFN-γ were significantly higher in the DM group than in the NC group (p < 0.05), whereas in the resveratrol-treated groups (NB and DB), the levels were relatively lower than those in the corresponding groups. The DM group showed reduced levels of DNA methylation at the specific cytosine phosphate guanosine sites of IL-1β, IL-6, TNF-α, and IFN-γ, relative to those in the NC group (p < 0.01), and these levels were increased by resveratrol. In contrast, IL-10 was dramatically methylated and showed decreased expression in response to high glucose, and resveratrol reversed this effect. These results demonstrate that the inflammatory response is involved in diabetic macroangiopathy. Resveratrol inhibits the expression of proinflammatory cytokines and thus may have a protective effect on the aorta in hyperglycemia. Thus, DNA methylation, an epigenetic gene silencing signal, may be responsible for these two phenomena.

Interleukin-10-1082 gene polymorphism is associated with papillary thyroid cancer

The etiopathogenesis of thyroid cancer has not been clearly elucidated although the role of chronical inflammation and the imbalance between pro- and anti-inflammatory cytokines may play a role in the etiology. The aim of the present study was to investigate whether cytokine gene polymorphisms are associated with papillary thyroid cancer (PTC), and to evaluate the relationship between genotypes and clinical/laboratory manifestation of PTC. Tumor necrosis factorα (TNFα) G-308A (rs 1800629), interleukin-6 (IL-6) G-174C (rs 1800795) and IL-10 A-1082G (rs 1800896) single nucleotide polymorphisms in DNA from peripheral blood leukocytes of 190 patients with thyroid cancer and 216 healthy controls were investigated by real-time PCR combined with melting curve analysis. There was no notable risk for PTC afflicted by TNFα-308 and IL-6-174 alone. However, IL-10-1082 G allele frequency were higher among PTC patients than healthy controls (p=0.009). The patients with IL-10-1082 GG geotype have twofold increased risk of developing thyroid cancer according to AA genotype (OR 2.07, 95% CI 1.21-3.55). In addition, the concomitant presence of IL-10-1082 G allele (GG+AG genotypes) together with IL-6 -174 GG genotype has a nearly twofold increased risk for thyroid cancer (OR 1.75 with 95% CI 1.00-3.05, p=0.049). We suggest that IL-10-1082 G allele is associated with an increased risk of PTC. The polymorphism of IL-10 gene can improve our knowledge about the pathogenesis of PTC, and could provide to estimate people at the increased risk for PTC.

-174G/C polymorphism in the interleukin-6 promoter is differently associated with prostate cancer incidence depending on race

Interleukin-6 (IL-6), a pro-inflammatory cytokine, is involved in prostate cancer progression, including androgen independence. Serum IL-6 levels also correlate with prostate tumor burden, prostate-specific antigen levels and metastasis. Since circulating cytokine levels vary considerably inter-individually, such variation could be linked to genetic factors, including genetic polymorphism. The -174G>C/rs1800795 polymorphism in the IL-6 promoter is functionally relevant in terms of transcriptional regulation and disease association. We investigated a possible association of the -174G/C polymorphism with prostate cancer. Since significant racial disparities exist in prostate cancer incidence, we also investigated this association between the -174G/C polymorphism and prostate cancer in Caucasians and African-Americans, separately. Direct sequencing of the PCR amplicon from genomic DNA was used for genotyping rs1800795 in all subjects [age-matched controls (N = 140) and prostate cancer patients (N = 164)]. Sample size and power was calculated using the PGA software. We found the GG genotype to be associated with increased risk of prostate cancer in Caucasian subjects, whereas the CC genotype was associated with increased risk in the African-American sample set. Such a dimorphic genotypic association with cancer and race is unique and suggests a complex gene-gene and gene-environment interaction.

TNF-α, IL6, and IL10 polymorphisms and the effect of physical exercise on inflammatory parameters and physical performance in elderly women

High levels of inflammatory mediators are associated with reduced physical capabilities and muscle function in the elderly. Single nucleotide polymorphisms (SNPs) may affect the expression and synthesis of these molecules, thus influencing the intensity of the inflammatory response and susceptibility to certain diseases. Physical exercise may attenuate age-related chronic inflammation and improve physical performance. This study evaluated the interaction between the SNP rs1800629 in TNF-α, rs1800795 in IL6, and rs1800896 in IL10 and the effect of physical exercise on physical performance and inflammation in elderly women. There was a significant interaction between rs1800629 and the effect of exercise on physical performance and between the combined 3-SNP genotype and changes in physical performance in response to exercise. These SNPs did not influence the effect of exercise on inflammatory parameters. Elderly women with a combination of genotypes associated with an anti-inflammatory profile (low TNF-α and IL-6 production, high IL-10 production) showed better physical performance independent of exercise modality, evidence of an interactive influence of genetic and environmental factors on improving physical performance in elderly women.

The interleukin-6 -147 g/c polymorphism is associated with increased risk of coronary artery disease in young South African Indian men

BACKGROUND

Interleukin-6 (IL-6) is a proinflammatory cytokine involved in the pathogenesis of chronic inflammatory diseases such as coronary artery disease (CAD). The -174 IL-6 G/C promoter polymorphism influences mRNA levels and protein expression and is implicated in CAD. The Indian population in South Africa, unlike the black community, has a high prevalence of premature CAD. This polymorphism has not been fully explored in this population. The present study assessed the -174 IL-6 G/C polymorphism in young Indian patients with angiographically documented CAD and compared them with age- and gender-matched Indian and black control subjects.

METHODS

Polymorphic variants were assessed by polymerase chain reaction-restriction fragment length polymorphism, and IL-6 levels were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

The -174 IL-6 C allele was found with a higher frequency (23%) in the total Indian group compared to 2% in the black participants [P<0.0001, odds ratio (OR)=0.05, 95% confidence interval (CI) 0.018-0.14). The difference in frequency was more pronounced when Indian controls were compared to black controls (29% vs. 2%, respectively) (P<0.0001, OR=0.05, 95% CI 0.02-0.17). A significant association between the -174 IL-6 G allele and CAD was found in Indian patients compared to Indian controls (84% in cases vs. 71% in Indian controls; P=0.043, OR=0.47 95% CI 0.23-0.95). Levels of IL-6 in circulation were higher in black controls (6.62±0.63 pg/mL) compared to Indian controls (2.51±0.57 pg/mL) and CAD patients (1.46±0.36 pg/mL) (P<0.0001). Levels of IL-6 were higher in all groups with homozygous -174 IL-6 C alleles, but only significant in the healthy Indian control group (GG 3.73±0.94 pg/mL vs. GC/CC 0.89±0.5 pg/mL, P=0.0001).

CONCLUSION

The presence of the IL-6 -174 G allele influences levels of IL-6 and increases the risk of CAD in South African Indians.

Genes, physical fitness and ageing

Persons aged 80 years and older are the fastest growing segment of the population. As more individuals live longer, we should try to understand the mechanisms involved in healthy ageing and preserving functional independence in later life. In elderly people, functional independence is directly dependent on physical fitness, and ageing is inevitably associated with the declining functions of systems and organs (heart, lungs, blood vessels, skeletal muscles) that determine physical fitness. Thus, age-related diminished physical fitness contributes to the development of sarcopenia, frailty or disability, all of which severely deteriorate independent living and thus quality of life. Ageing is a complex process involving many variables that interact with one another, including - besides lifestyle factors or chronic diseases - genetics. Thus, several studies have examined the contribution of genetic endowment to a decline in physical fitness and subsequent loss of independence in later life. In this review, we compile information, including data from heritability, candidate-gene association, linkage and genome-wide association studies, on genetic factors that could influence physical fitness in the elderly.

Interaction between cytokine gene polymorphisms and the effect of physical exercise on clinical and inflammatory parameters in older women: study protocol for a randomized controlled trial

Background

Aging is associated with chronic low-grade inflammatory activity with an elevation of cytokine levels. An association between regular physical activity and reduction of blood levels of anti-inflammatory cytokines is demonstrated in the literature pointing to an anti-inflammatory effect related to exercise. However, there is no consensus regarding which type of exercise and which parameters are the most appropriate to influence inflammatory markers. Evidence indicates that the single nucleotide polymorphism (SNP) can influence the synthesis of those cytokines affecting their production.

Methods/Design

The design of this study is a randomized controlled trial. The aim of this study is to investigate the interaction between the cytokine genes SNP and the effect of physical activity on older women. The main outcomes are: serum levels of sTNFR-1, sTNFR-2, interleukin (IL)-6, IL-10, measured by the ELISA method; genotyping of tumor necrosis factor- (TNF)-alpha (rs1800629), IL6 (rs1800795), IL10 (rs1800896) by the TaqMan Method (Applied Biosystems, Foster City, CA, USA); and physical performance assessed by Timed Up and Go and 10-Meter Walk Tests. Secondary outcomes include: Geriatric Depression Scale, Perceived Stress Scaleand aerobic capacity, assessed by the six-minute walk; and lower limb muscle strength, using an isokinetic dinamometer (Biodex Medical Systems, Inc., Shirley, NY,USA). Both exercise protocols will be performed three times a week for 10 weeks, 30 sessions in total.

Discussion

Investigating the interaction between genetic factors and exercise effects of both protocols of exercise on the levels of inflammatory cytokine levels can contribute to guide clinical practice related to treatment and prevention of functional changes due to chronic inflammatory activity in older adults. This approach could develop new perspectives on preventive and treatment proposals in physical therapy and in the management of the older patient.

Trial registration

(ReBEC) RBR9v9cwf

Lessons from genome-wide association studies findings in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder with a complex genetic background. Recent genome-wide association studies (GWAS) have placed important new contributors into the genetic framework of early- and late-onset forms of this dementia. Besides confirming the major role of classic allelic variants (e.g. apolipoprotein E) in the development of AD, GWAS have thus far implicated over 20 single nucleotide polymorphisms in AD. In this review, we summarize the findings of 16 AD-based GWAS performed to date whose public registries are available at the National Human Genome Research Institute, with an emphasis on understanding whether the polymorphic markers under consideration support functional implications to the pathophysiological role of the major genetic risk factors unraveled by GWAS.

Association between the interleukin-6 promoter polymorphism -174G/C and serum lipoprotein(a) concentrations in humans

BACKGROUND

Lipoprotein(a) [Lp(a)] is an independent risk factor for cardiovascular disease. The interleukin-6 (IL-6) receptor antagonist tocilizumab has been shown to lower serum Lp(a) concentrations. We investigated whether the IL-6 single nucleotide polymorphism -174G/C is associated with baseline serum Lp(a) concentrations.

METHODOLOGY/PRINCIPAL FINDINGS

We divided 2321 subjects from the Lipid Analytic Cologne (LIANCO) cohort into 2 groups, the ones with substantially elevated Lp(a), defined as concentrations ≥60 mg/dl (n = 510), and the ones with Lp(a) <60 mg/dl (n = 1811). The association with the genotypes GG (33.7%), GC (50.75%) and CC (15.55%) was investigated. The GC and the CC genotype were associated with a significantly increased odds ratio of having substantially elevated Lp(a) concentrations (OR = 1.3, 95% CI 1.04 to 1.63, P = 0.02 and OR = 1.44, 95% CI 1.06 to 1.93, P = 0.018). These associations remained significant after adjusting for age, sex, smoking behavior, body mass index, serum lipoproteins, hypertension and diabetes. Of these covariates, only LDL cholesterol was significantly and independently associated with elevated Lp(a) concentrations.

CONCLUSIONS/SIGNIFICANCE

The IL-6 single nucleotide polymorphism -174G/C is associated with increased odds of having elevated Lp(a). Whether this association plays a role in the Lp(a)-lowering effects of IL-6 receptor antagonists remains to be established.