Lack of association between rs1800795 (-174 G/C) polymorphism in the promoter region of interleukin-6 gene and susceptibility to type 2 diabetes in Isfahan population

The Concentrations of Interleukin-6, Insulin, and Glucagon in the Context of Obesity and Type 2 Diabetes and Single Nucleotide Polymorphisms in IL6 and INS Genes

Obesity and diabetes are a problem of modern medicine. Although the environmental factors contributing to the development of these diseases are widely known, research into genetic factors is still ongoing. At the same time, the role of inflammation in the pathophysiology of obesity and diabetes is increasingly emphasized. Therefore, the purpose of this study was to investigate the influence of two selected polymorphisms (rs1800795 and rs3842729) on the development of obesity and type 2 diabetes. In this study, 118 participants were examined, including a control group (nonobese and nondiabetic group), an obese group, and a diabetic group. Genotype analysis was performed using the PCR-RFLP method. It has been shown that in patients with the G/G genotype within the rs1800795 polymorphism (IL6), the chance of developing type 2 diabetes is several times lower compared to patients with the G/C and C/C genotypes. However, the rs3842729 polymorphism (INS) does not directly affect the risk of obesity or type 2 diabetes (T2D), although elevated insulin concentrations have been observed in obese and diabetic patients. These results confirm the impact of the rs1800795 polymorphism on the development of diabetes; however, this relationship is more complex and requires further research on other factors.

Evaluation of IL-6 and IL-17A gene polymorphisms in Iraqi patients infected with COVID-19 and type 2 diabetes mellitus

BACKGROUND

In patients with COVID-19, diabetes mellitus type 2 (T2DM) increases the risk of hospitalization and death. Patients who have IL-6 and IL-17A single nucleotide polymorphisms (SNPs) are more likely to have severe COVID-19. This study aims to determine whether SNPs of the IL-6 gene at rs1800795 (G > C) and the IL-17A gene at rs2275913 (G > A) are associated with COVID-19 and T2DM in the Iraqi population.

PATIENTS AND METHODS

Twenty-four people were divided into 4 groups as follows: six patients with severe COVID-19 and T2DM were placed in Group 1 as "G1", six patients with COVID-19 but no T2DM were placed in Group 2 as "G2", and six patients with T2DM were placed in Group 3 as "G3". There were also six healthy controls included in each group. Polymerase chain reaction (PCR) was used to amplify the target genes after genomic DNA from the blood samples was extracted. Sanger sequencing was used to find the SNPs in both the forward and reverse directions for each sample.

RESULTS

In the case of IL-6 SNP at rs1800795, the GG genotype was more common in "G3", the CC genotype was less common in all patient groups than in controls, and the GC allele was more common in "G2" than in the control group. In comparison to the controls, the three patient groups showed lower frequencies of the C allele and higher frequencies of the G allele. Regarding IL-17A gene polymorphism, the AA and GA genotypes were more prevalent in "G2" and "G3", respectively. The GG genotype and G allele frequency dropped in all patient groups compared to the control group, whereas the A allele frequency increased in all patient groups.

CONCLUSIONS

The IL-6 gene at rs1800795 (G/C) and the IL-17A gene at rs2275913 (G/A) loci were associated with COVID-19 and T2DM in Iraqi population.

IL-6 gene rs1800795 polymorphism and diabetes mellitus: a comprehensive analysis involving 42,150 participants from a meta-analysis

BACKGROUND

Over the past two decades, several studies have focused on the association between a common polymorphism (rs1800795) from interleukin-6 (IL-6) gene and Diabetes Mellitus (DM) risk. However, the results remain ambiguous and indefinite.

METHODS

A comprehensive analysis was performed to explore this relationship. A search was conducted in the PubMed, Embase, Chinese (CNKI and Wanfang), and GWAS Catalog databases, covering all publications until February 10, 2022. Odds ratios (OR) with 95% confidence intervals (CI) were used to evaluate the strength of the association. Publication bias was assessed using both Begg and Egger tests.

RESULTS

Overall, 34 case-control studies with 7257 T2DM patients and 15,598 controls, and 12 case-control studies (10,264 T1DM patients and 9031 health controls) were included in the analysis. A significantly lower association was observed between the rs1800795 polymorphism and T2DM risk in Asians, mixed population, and hospital-based (HB) subgroups (C-allele vs. G-allele: OR = 0.76, 95% CI  0.58-0.99, P = 0.039 for Asians; CG vs. GG: OR = 0.74, 95% CI  0.58-0.94, P = 0.014 for mixed population; CC vs. GG: OR = 0.61, 95% CI  0.41-0.90, P = 0.014 for HB). However, increased associations were found from total, mixed population, and HB subgroups between rs1800795 polymorphism and T1DM susceptibility (CG vs. GG: OR = 1.32, 95% CI 1.01-1.74, P = 0.043 for total population, CC vs. GG: OR = 2.45, 95% CI 1.18-5.07, P = 0.016 for mixed individuals; C-allele vs. G-allele: OR = 1.29, 95% CI 1.07-1.56, P = 0.0009 for HB subgroup).

CONCLUSIONS

In summary, there is definite evidence to confirm that IL-6 rs1800795 polymorphism is associated with susceptibility to decreased T2DM and increased T1DM.

The Role of Plasma Interleukin-6 Levels on Atherosclerotic Cardiovascular Disease and Cardiovascular Mortality Risk Scores in Javanese Patients with Chronic Kidney Disease

Interleukin-6 (IL-6) has been identified as an important pro-inflammatory factor involved in mediating the severity of chronic kidney disease (CKD). This study sought to determine the effect of plasma IL-6 levels on atherosclerotic cardiovascular disease (ASCVD) and cardiovascular mortality risk scores in Javanese CKD patients. We also analyzed the frequency of IL-6 G174C single nucleotide polymorphism (SNP) in the population. This study was a cross-sectional study involving seventy-three patients of Javanese ethnic origin with stable chronic kidney disease. We assessed the ASCVD risk score, cardiovascular mortality score, genotyping of IL-6 G174C SNP, and plasma IL-6 levels in these patients. The genotype distribution and allele frequencies of the IL-6 G174C SNP were predominated by the G genotype/allele (GG: 97.26%, GC: 1.37%, CC: 1.37%, G-allele: 97.95%, and C-allele: 2.05%). Despite the fact that plasma IL-6 levels did not directly affect cardiovascular mortality risk, further analysis revealed its direct effect on the ASCVD risk score (path coefficient = 0.184, p = 0.043, 95% CI = 0.018−0.380), which in turn affected cardiovascular mortality risk (path coefficient = 0.851, p = <0.01, 95% CI = 0.714−0.925). In conclusion, plasma IL-6 levels play important roles on ASCVD risk and cardiovascular mortality risk in Javanese patients with CKD.

Meta-analysis: Interleukin 6 gene -174G/C polymorphism associated with type 2 diabetes mellitus and interleukin 6 changes

The gene coding interleukin 6 (IL‐6) is a promising candidate in predisposition to type 2 diabetes mellitus (T2DM). This study aimed to meta‐analytically examine the association of IL‐6 gene −174G/C polymorphism with T2DM and circulating IL‐6 changes across −174G/C genotypes. Odds ratio (OR) and standard mean difference (SMD) with 95% confidence interval (CI) were calculated. Twenty‐five articles were meta‐analysed, with 20 articles for T2DM risk and 9 articles for circulating IL‐6 changes. Overall, there was no detectable significance for the association between −174G/C polymorphism and T2DM, and this association was relatively obvious under dominant model (OR: 0.82, 95% CI: 0.56‐1.21). Improved heterogeneity was seen in some subgroups, with statistical significance found in studies involving subjects of mixed races (OR: 0.63, 95% CI: 0.46‐0.86). Begg's and filled funnel plots, along with Egger's tests revealed week evidence of publication bias. In genotype‐phenotype analyses, carriers of −174CC and −174CG genotypes separately had 0.10 and 0.03 lower concentrations (pg/mL) of circulating IL‐6 than −174GG carriers. Albeit no detectable significance for the association of −174G/C with T2DM, our findings provided suggestive evidence on a dose‐dependent relation between −174G/C mutant alleles and circulating IL‐6 concentrations, indicating possible implication of this polymorphism in the pathogenesis of T2DM.

Relationship between TP53 and interleukin-6 gene variants and the risk of types 1 and 2 diabetes mellitus development in the Kermanshah province

Diabetes mellitus (DM) is a metabolic disorder that results from insufficient secretion or insulin resistance, or both. Insulin secretion deficiency leads to chronic hyperglycemia along with impaired metabolism of proteins, lipids, and carbohydrates. This study aimed to investigate the TP53 gene SNP (single nucleotide polymorphism) rs1042522 genotype and the interleukin-6 (IL-6) gene SNP rs1800795 genotype in DM and control groups. This study was performed on 70 patients with type 1 DM, 100 patients with type 2 DM without related complications, 66 control subjects for type 1 DM, and 95 control subjects for type 2 DM. The control groups were matched regarding age and gender and did not have a familial relationship with the patient groups. All the subjects were residents of Kermanshah, located in the western part of Iran. Polymorphisms of TP53 and IL-6 genes were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Lipid profile, fasting blood glucose, and HbA1c were measured using the ELISA and immunoturbidometric methods. The frequency of genotypes (CC, CG, GG) of the TP53 gene codon 72 in type 1 DM and its control group were significantly different (P= 0.013). Likewise, the frequency of genotypes (CC, CG, GG) of the TP53 gene codon 72 was significantly different between type 2 DM and control groups (P <0.001). The frequency of genotypes (GG, GC, CC) of G174C polymorphisms in the IL-6 gene was different between type 1 DM and control group as well as between type 2 DM and its control group, but it was not statistically significant. SNP rs1042522 genotypes in the dominant form (CG + GG vs. CC) (OR= 3.880; P < 0.001) and alleles G vs. C alleles (OR= 0.384; P < 0.001) increased the risk of type 2 DM significantly. There was no significant difference between type 1 and type 2 DM groups and respected control groups regarding the frequency of the IL-6 gene SNP rs1800795 alleles. The G allele of SNP rs1042522 encoding the TP53 gene increases the risk of developing DM in the population of the Kermanshah province, Iran.

The association between Interleukin-6 rs1800795/rs1800797 polymorphisms and risk of rotator cuff tear in a Chinese population

Expression of proinflammatory cytokines, such as interleukin (IL)-6 (IL-6) and metalloproteases, are elevated in patients with rotator cuff tear (RCT). In order to investigate the role of IL-6 gene polymorphisms on RCT risk, we genotyped two SNPs on IL-6 gene (rs1800795 and rs1800797) in 138 RCT patients and 137 healthy controls using polymerase chain reaction (PCR) and Sanger sequencing. The IL-6 expression in shoulder joint synovial fluid was determined by using enzyme-linked immunosorbent assay (ELISA) method. The constant score and visual analog scale (VAS) were used to evaluate the clinical outcome of two s (surgicsal vs. conservative) for RCT patients. For rs1800795, individuals with the GG genotype or G allele had significantly higher risk of RCT. Elevated risk of tear size was associated with the GG genotype of the rs1800795 polymorphism. The IL-6 rs1800797 polymorphism was also associated with an increased risk of RCT, especially among female, drinkers, and individuals with B(MI) < 25 kg/m². The elevated levels of IL-6 gene were observed among the mutant genotype of rs1800795/rs1800797 polymorphism. Surgical group is significantly better than conservative treatment from the perspective of constant score and VAS. Furthermore, CG genotype of rs1800795 polymorphism increased the constant score at 6 months in comparison with CC genotype. In conclusion, our study supports a role of IL-6 rs1800795/rs1800797 polymorphisms on increased RCT risk. The RCT patients with CG genotype of rs1800795 polymorphism have more obvious surgical treatment effects by influencing the IL-6 expression.

Interleukin-1β and interleukin-6 gene polymorphisms in Egyptian sickle cell disease patients

Background

Sickle cell disease (SCD) is a disorder characterized by a heterogeneous clinical outcome. Interleukin-1β (IL-1β) and interleukin-6 (IL-6) are important mediators of inflammatory response. Genetic modifiers that alter cytokine levels may contribute to the clinical variability of SCD. The present study investigated the associations of IL-1β + 3954 C>T and IL-6 (− 174G>C and − 597 G>A) gene polymorphisms with clinical and laboratory data in SCD patients. The study was conducted on 100 SCD patients (59 sickle cell anemia patients “SS” and 41 sickle beta thalassemia patients “Sβ”). Fifty age- and sex-matched healthy volunteers were included as a control group. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used for the detection of IL-1β and IL-6 gene polymorphisms.

Results

The homomutant genotypes of IL-1β (+ 3954 C>T), IL-6 (− 174G>C), and IL-6 (− 597 G>A) were infrequently presented among SCD patients and control group. No significant differences were detected between SS, Sβ patients, and control group as regards the genotypic frequencies and allele distributions of the studied polymorphisms. As regards the clinical complications, the mutant genotypes of IL-1β (+ 3954 C>T) had a significantly higher frequency among Sβ patients with splenomegaly. Hemoglobin is significantly lower in SS patients with mutant allele (AA and GA) for IL-6 (− 597 G>A) (P = 0.005), while Sβ patients with mutant genotype for IL-6 (− 597 G>A) had significantly higher total leucocytic count (P = 0.031).

Conclusion

IL-1β (+ 3954 C>T), IL-6 (− 174G>C), and IL-6 (− 597G>A) polymorphisms are not associated with disease phenotype. However, IL6 polymorphism (− 597 G>A) might predispose to underlying inflammatory process.

IL-1β and IL-1Ra Variant Profiles in Turkish Patients with Diabetic Peripheral Neuropathy

BACKGROUND

Diabetic peripheral neuropathy (DPN) is one of the most common complications of Type 2 diabetes mellitus (T2DM). This study was conducted to investigate the possible association between interleukin-1β (IL-1β) rs16944 /IL-1 receptor antagonist (IL-1Ra) VNTR variants and genetic susceptibility to DPN in a Turkish cohort.

METHODS

A total of 200 subjects were enrolled in this study, 98 patients with DPN and 102 cases of age and sex-matched healthy controls. Genotyping was performed for all individuals using PCR-RFLP analysis.

RESULTS

IL-1β rs16944 CC genotype had a 3.20-fold increased risk for DPN (p=0.0003, OR=3.20, 95% Cl:1.72-5.96). IL-1β rs16944 CT genotype was higher in healthy control than patients (p=0.004). IL-1β rs16944 C allele was higher in the patient group compared to controls while T allele was lower in patients than controls (p=0.003). IL-1Ra VNTR a1/a1 and a2/a2 genotypes were lower in DPN patients while a1/a2 genotype was higher in patients (p=0.045). The patients carrying a1/T haplotype had decreased risk of DPN than control groups (p=0.004). The patients carrying a2/a2 genotype had lower HDL level (p=0.039). The subjects carrying a2/a2 genotype had higher total cholesterol level while the subjects carrying a1/a2 genotype had lower total cholesterol (p=0.026 and p=0.037, respectively). IL-1Ra a1 allele was associated with higher HDL level (p=0.041).

CONCLUSION

Findings of this study indicated that the IL-1β rs16944 and IL-1Ra VNTR variants are probably to be associated with susceptibility DPN risk in a Turkish cohort.

Association among interleukin-6 gene polymorphisms, type 2 diabetes mellitus, and chronic periodontitis: a pilot study

AIM

The purpose of this pilot study was to determine the association between single nucleotide polymorphisms (-174 G>C) in the interleukin-6 (IL-6) gene with chronic periodontitis (CP) and type 2 diabetes mellitus (T2DM) in south Indian population.

METHODS

Genomic DNA was obtained from the white blood cells of 30 patients with T2DM, 30 patients with CP, 30 patients with T2DM with CP, and 30 controls. DNA was amplified using polymerase chain reaction with specific primers flanking the locus -174 of the IL-6 gene and further genotyped using the restriction fragment length polymorphism method. The genotype distribution and allele frequencies between the study groups were determined using χ² -test. The relative risk was estimated with a 95% confidence interval.

RESULTS

The CP group (26.7%) displayed a greater percentage of GC genotype (P = 0.026) when compared to the control group (3.3%). A statistically-significant difference in the allele frequencies was found between the control and CP group with the C-allele frequency being greater (0.13) in the CP group than normal controls (0.02).

CONCLUSION

The GC genotype was found to be the risk genotype and the C allele was found to be the risk allele for the development of CP.