Associations of TNFα-308G/A and TNFα-238G/A Polymorphisms with Ischemic Stroke in East Asians and Non-East Asians: A Meta-Analysis

Association of TNF-α (-308G/A) Gene Polymorphism with Changes in Circulating TNF-α Levels in Response to CPAP Treatment in Adults with Coronary Artery Disease and Obstructive Sleep Apnea

RATIONALE

We recently demonstrated that patients with coronary artery disease (CAD) and obstructive sleep apnea (OSA) carrying the tumor necrosis factor-alpha (TNF-α) A allele had increased circulating TNF-α levels compared with the ones carrying the TNF-α G allele. In the current study, we addressed the effect of TNF-α (-308G/A) gene polymorphism on circulating TNF-α levels following continuous positive airway pressure (CPAP) therapy.

METHODS

This study was a secondary analysis of the RICCADSA trial (NCT00519597) conducted in Sweden. CAD patients with OSA (apnea-hypopnea index) of ≥15 events/h and an Epworth Sleepiness Scale (ESS) score of <10 were randomized to CPAP or no-CPAP groups, and OSA patients with an ESS score of ≥10 were offered CPAP treatment. Blood samples were obtained at baseline and 12-month follow-up visits. TNF-α was measured by immunoassay (Luminex, R&D Systems). Genotyping of TNF-α-308G/A (single nucleotide polymorphism Rs1800629) was performed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

In all, 239 participants (206 men and 33 women; mean age 64.9 (SD 7.7) years) with polymorphism data and circulating levels of TNF-α at baseline and 1-year follow-up visits were included. The median circulating TNF-α values fell in both groups between baseline and 12 months with no significant within- or between-group differences. In a multivariate linear regression model, a significant change in circulating TNF-α levels from baseline across the genotypes from GA to GA and GA to AA (standardized β-coefficient -0.129, 95% confidence interval (CI) -1.82; -0.12; p = 0.025) was observed in the entire cohort. The association was more pronounced among the individuals who were using the device for at least 4 h/night (n = 86; standardized β-coefficient -2.979 (95% CI -6.11; -1.21); p = 0.004)), whereas no significant association was found among the patients who were non-adherent or randomized to no-CPAP. The participants carrying the TNF-α A allele were less responsive to CPAP treatment regarding the decline in circulating TNF-α despite CPAP adherence (standardized β-coefficient -0.212, (95% CI -5.66; -1.01); p = 0.005).

CONCLUSIONS

Our results suggest that TNF-α (-308G/A) gene polymorphism is associated with changes in circulating TNF-α levels in response to CPAP treatment in adults with CAD and OSA.

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

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

TNF-α polymorphisms might influence predisposition to periodontitis: A meta-analysis

BACKGROUND

Tumor necrosis factor-α (TNF-α) polymorphisms might influence predisposition to periodontitis, but the results of already published studies were still controversial and ambiguous. So the authors designed this meta-analysis to more precisely estimate relationship between TNF-α polymorphisms and periodontitis by pooling the results of already published related studies.

METHODS

The authors searched Pubmed, Embase, Web of Science and CNKI for already published studies. Forty-five already published studies were pooled analyzed in this meta-analysis.

RESULTS

The crude pooled meta-analyses results showed that distributions of TNF-α rs361525, rs1800629, rs1800630 and rs1799964 polymorphisms among patients and controls differed significantly, which suggested that these polymorphisms might influence predisposition to periodontitis in the general population. We also got similar significant results for rs361525, rs1800629, rs1800630 and rs1799964 polymorphisms in subgroup analyses in Asians. The crude findings were further subjected to Bonferroni correction to account for multiple comparisons. For rs361525, rs1800629 and rs1799964 polymorphisms, basically no changes of results were detected. But for rs1800630 polymorphism, the results were no longer significant after adjustment for multiple comparisons.

CONCLUSIONS

This meta-analysis suggested that TNF-α rs361525, rs1800629 and rs1799964 polymorphisms might influence predisposition to periodontitis, particularly in Asians.

A Meta-Analysis of the Relationship between Tumor Necrosis Factor-α Polymorphisms and Psoriasis

BACKGROUND

Some previous studies already explored associations between tumor necrosis factor-α (TNF-α) polymorphisms and psoriasis, with conflicting findings. Here, we aimed to better analyze the relationship between TNF-α polymorphisms and psoriasis in a larger pooled population by performing a meta-analysis.

METHODS

We searched Pubmed, Embase, Web of Science and CNKI for related articles. We calculated OR and 95% CI to estimate whether there are genetic associations between TNF-α polymorphisms and psoriasis.

RESULTS

Twenty-nine studies were included for this meta-analysis. TNF-α-238 G/A (dominant comparison: OR 0.44, 95% CI 0.34-0.59; recessive comparison: OR 1.63, 95% CI 1.03-2.57; overdominant comparison: OR 2.21, 95% CI 1.71-2.85; allele comparison: OR 0.48, 95% CI 0.36-0.62) and -857 C/T (dominant comparison: OR 0.58, 95% CI 0.41-0.80; overdominant comparison: OR 1.58, 95% CI 1.12-2.23; allele comparison: OR 0.62, 95% CI 0. 0.47-0.82) polymorphisms were found to be significantly associated with psoriasis in the general population. Subgroup analyses indicated that the -238 G/A polymorphism was significantly associated with psoriasis in Caucasians and East Asians, the -308 G/A polymorphism was significantly associated with psoriasis in East Asians, and the -857 C/T polymorphism was significantly associated with psoriasis in Caucasians.

CONCLUSIONS

TNF-α -238 G/A, -308 G/A and -857 C/T polymorphisms could be used to identity individuals with elevated susceptibility to psoriasis in certain populations.

Promoter Polymorphism (-308G/A) of Tumor Necrosis Factor-Alpha (TNF-α) Gene and Asthma Risk: An Updated Meta-Analysis

Background and Aims: The relationship between the promoter polymorphism (-308G/A) of the tumor necrosis factor-alpha (TNF-α) gene and the susceptibility to asthma has been tested in several studies. However, the results have been inconsistent. Therefore, we performed an updated meta-analysis to evaluate the relationship between this promoter polymorphism of the TNF-α gene and the risk of asthma. Methods: Fifty case-control studies were included in this meta-analysis which provided 17,937 controls and 9961 asthma patients. The pooled p-value, odds ratio (OR), and 95% confidence interval (95% CI) were used to investigate the strength of the association of this polymorphism of the TNF-α gene with the risk of asthma. The meta-analysis was carried out by Comprehensive Meta-Analysis software. Results: The results of our meta-analysis revealed that the TNF-α polymorphism (-308, G/A) was strongly associated with the risk of asthma (p < 0.05 in the allelic, dominant, and recessive models, respectively). In further analyses, based on age group and ethnicity, we observed this association for all subpopulations examined (p < 0.05 in allelic, dominant, and recessive models, respectively). Conclusion: This large-scale meta-analysis supports a strong association between the TNF-α gene promoter polymorphism (-308G/A) and the development to asthma in both children and adults.

Serum profile of cytokines and their genetic variants in metabolic syndrome and healthy subjects: a comparative study

AIM

To identify genetic variants in promoter areas of IL-6 -174 G>C and TNF-α -308 G>A in metabolic syndrome (Met S) and controls and associate them with Met S and serum cytokine levels.It was a cross-sectional study, including 224 cases of Met S and 200 controls. A fasting blood sample was taken and biochemical parameters including serum glucose, insulin, lipid profile, interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were measured. Restriction fragment length polymorphism was used to identify the genetic variants of IL-6 and TNF-α. Serum levels of IL-6 and TNF-α and insulin resistance were significantly higher in cases than the controls. IL-6 showed significant positive correlation with HOMA-IR and TNF-α. CC genotype of IL-6 was associated with the increased risk of Met S (P=0.016, OR for CC vs GC+GG = 2.33, CI: 1.15-4.71). There was no significant difference of TNF-α genotypes between the cases and the controls. Serum TNF-α and IL-6 levels were significantly higher in AA and CC genotypes of TNF-α (-308 G>A) and IL-6 (-174 G>C) as compared with the GG (P=0.00 and P=0.001). Significant correlation of IL-6 with TNF-α and insulin resistance was observed that may provide us a therapeutic target for preventing metabolic derangements from insulin resistance.