Tumor necrosis factor-alpha 308G>A polymorphism and risk of rheumatic heart disease: a meta-analysis

Plausible Role of NLRP3 Inflammasome and Associated Cytokines in Pathogenesis of Rheumatic Heart Disease

Rheumatic heart disease (RHD) is a post-streptococcal sequela caused by Streptococcus pyogenes. The global burden of disease is high among people with low socio-economic status, with significant cases emerging every year despite global eradication efforts. The current treatment includes antibiotic therapies to target strep throat and rheumatic fever and valve replacement strategies as a corrective measure for chronic RHD patients. Valvular damage and valve calcification are considered to be the end-stage processes of the disease resulting from impairment of the endothelial arrangement due to immune infiltration. This immune infiltration is mediated by a cascade of events involving NLRP3 inflammasome activation. NLRP3 inflammasome is activated by wide range of stimuli including bacterial cell wall components like M proteins and leukocidal toxins like nicotinamide dehydrogenase (NADase) and streptolysin O (SLO) and these play a major role in sustaining the virulence of Streptococcus pyogenes and progression of RHD. In this review, we are discussing NLRP3 inflammasome and its plausible role in the pathogenesis of RHD by exploiting the host-pathogen interaction mainly focusing on the NLRP3 inflammasome-mediated cytokines IL-1β and IL-18. Different therapeutic approaches involving NLRP3 inflammasome inactivation, caspase-1 inhibition, and blockade of IL-1β and IL-18 are discussed in this review and may be promising for treating RHD patients.

The Genetic Control of the Rheumatic Heart: Closing the Genotype-Phenotype Gap

Rheumatic heart disease (RHD) is a heritable inflammatory condition characterized by carditis, arthritis, and systemic disease. Although remaining neglected, the last 3 years has seen some promising advances in RHD research. Whilst it is clear that RHD can be triggered by recurrent group A streptococcal infections, the mechanisms driving clinical progression are still poorly understood. This review summarizes our current understanding of the genetics implicated in this process and the genetic determinants that predispose some people to RHD. The evidence demonstrating the importance of individual cell types and cellular states in delineating causal genetic variants is discussed, highlighting phenotype/genotype correlations where possible. Genetic fine mapping and functional studies in extreme phenotypes, together with large-scale omics studies including genomics, transcriptomics, epigenomics, and metabolomics, are expected to provide new information not only on RHD but also on the mechanisms of other autoimmune diseases and facilitate future clinical translation.

Rheumatic heart disease: A review of the current status of global research activity

Rheumatic heart disease (RHD) is a serious and long-term consequence of acute rheumatic fever (ARF), an autoimmune sequela of a mucosal infection by Streptococcus pyogenes (Group A Streptococcus, Strep A). The pathogenesis of ARF and RHD is complex and not fully understood but involves host and bacterial factors, molecular mimicry, and aberrant host innate and adaptive immune responses that result in loss of self-tolerance and subsequent cross-reactivity with host tissues. RHD is entirely preventable yet claims an estimated 320 000 lives annually. The major burden of disease is carried by developing nations and Indigenous populations within developed nations, including Australia. This review will focus on the epidemiology, pathogenesis and treatment of ARF and RHD in Australia, where: streptococcal pyoderma, rather than streptococcal pharyngitis, and Group C and Group G Streptococcus, have been implicated as antecedents to ARF; the rates of RHD in remote Indigenous communities are persistently among the highest in the world; government register-based programs coordinate disease screening and delivery of prophylaxis with variable success; and researchers are making significant progress in the development of a broad-spectrum vaccine against Strep A.

The effect of tumor necrosis factor alpha (-308G/a) and interferon gamma (+874T/a) polymorphisms on susceptibility to coronary heart disease

Background: Coronary heart disease (CHD) is a chronic inflammatory disease, which is still regarded as a major cause of morbidity and mortality worldwide. Several studies have suggested that polymorphisms in cytokine genes are associated with the pathogenesis of CHD. The genotype distribution of Tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) genes polymorphisms have been shown to be different in various ethnic populations. This study was aimed to investigate the association of TNF-α-308 G/A and IFN-γ + 874T/A polymorphisms with risk of CHD in an Iranian population. Methods: A total of 187 unrelated subjects comprised 96 CHD patients and 91 healthy controls were enrolled in this cross-sectional study. The TNF-α-308 G/A and IFN-γ + 874T/A polymorphisms were genotyped using amplification refractory mutation system-PCR (ARMS-PCR). The chi-square and logistic regression tests were used to calculate the odds ratios (ORs) as a measure of differences in genotype frequencies. Results: A significant differences in the allelic and genotypic distribution of TNF-α-308 G/A and IFN-γ + 874T/A polymorphisms was found between CHD patients and healthy controls (P = 0.017, P = 0.011, P = 0.006 and P = 0.002, respectively). Logistic regression analyses were also revealed statistically significant risk for CHD with respect to TNF-α-308 A and IFN-γ + 874 T carriers either in crude or after adjustment for potential confounders (P = 0.003 and P = 0.006, respectively). Conclusion: This study provides strong evidence supporting the association of TNF-α-308G/A and IFN-γ + 874T/A polymorphisms with the increased risk of CHD. Therefore, these two cytokine polymorphisms may play a role in predisposition to coronary heart disease.

Lack of Association Between TNF-α, IFN-γ, IL-10 Gene Polymorphisms and Rheumatic Heart Disease in South Indian Population

BACKGROUND

Proinflammatory and anti-inflammatory cytokines play a crucial role in the development and maintenance of immune mediated inflammatory diseases including rheumatic heart disease (RHD). Polymorphisms in tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL)-10 genes influence the differential cytokine expression as well as the pathogenesis of various inflammatory and autoimmune diseases.

OBJECTIVE

The aim of the study is to investigate the association between TNF-α, IFN-γ, and IL-10 gene polymorphisms and RHD in South Indian population.

MATERIALS AND METHODS

TNF-α (-308, -238), IFN-γ (+874), and IL-10 (-1082, -819, -592) gene polymorphisms were determined in 100 patients with RHD and 127 healthy siblings by PCR.

RESULTS

There was no significant difference in the genotype, allele, and haplotype frequencies of TNF-α, IFN-γ, and IL-10 polymorphisms between RHD patients and healthy siblings.

CONCLUSION

The present study suggests that TNF-α, IFN-γ, and IL-10 gene variants may not be associated with the development of RHD in South Indian population.

Tumor necrosis factor-alpha gene polymorphisms and susceptibility to ischemic heart disease: A systematic review and meta-analysis

BACKGROUND

A number of studies had reported the association between tumor necrosis factor-alpha (TNF-α) gene polymorphisms and ischemic heart disease (IHD) risk. However, the results remained controversial. Therefore, we performed a systematic review with multiple meta-analyses to provide the more precise estimations of the relationship.

METHODS

We systematically searched electronic databases (PubMed, the Web of Science, EMBASE, Medline, Chinese National Knowledge Infrastructure, WanFang and ChongQing VIP Database) for relevant studies published up to February 2017. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for assessing the association. The present meta-analysis was performed using STATA 12.0 software.

RESULTS

In total, 45 articles with 17,375 cases and 15,375 controls involved were included. Pooled ORs revealed a significant association between TNF-α -308G/A gene polymorphism and IHD (A vs. G: OR = 1.22, 95% CI = 1.10-1.35; (AA + GA) vs. GG: OR = 1.18, 95% CI = 1.03-1.36; (AA vs. (GA+GG): OR = 1.37, 95% CI = 1.08-1.75)), indicating that the TNF-α -308A allele might be an important risk factor for IHD. No association between other TNF-α gene polymorphisms and susceptibility to IHD were observed. No publication bias were found. Sensitivity analyses indicated that our results were stable.

CONCLUSION

The present study indicated a possible association between the TNF-α -308G/A gene polymorphism and IHD risk. However, evidence was limited to confirm the role of TNF-α -238G/A, -857C/T, -863C/A, -1031T/C and other TNF-α gene polymorphisms in the risk of IHD.

Parameters indicative of persistence of valvular pathology at initial diagnosis in acute rheumatic carditis: the role of albumin and CD19 expression

OBJECTIVE

The aim of this study is to define the predictors of chronic carditis in patients with acute rheumatic carditis (ARC).

METHODS

Patients diagnosed with ARC between May 2010 and May 2011 were included in the study. Echocardiography, electrocardiography, lymphocyte subset analysis, acute phase reactants, plasma albumin levels, and antistreptolysin-O (ASO) tests were performed at initial presentation. The echocardiographic assessments were repeated at the sixth month of follow-up. The patients were divided into two groups according to persistence of valvular pathology at 6th month as Group 1 and Group 2, and all clinical and laboratory parameters at admission were compared between two groups of valvular involvement.

RESULTS

During the one-year study period, 22 patients had valvular disease. Seventeen (77.2%) patients showed regression in valvular pathology. An initial mild regurgitation disappeared in eight patients (36.3%). Among seven (31.8%) patients with moderate regurgitation initially, the regurgitation disappeared in three, and four patients improved to mild regurgitation. Two patients with a severe regurgitation initially improved to moderate regurgitation (9.1%). In five (22.8%) patients, the grade of regurgitation [moderate regurgitation in one (4.6%), and severe regurgitation in 4 (18.2%)] remained unchanged. The albumin level was significantly lower at diagnosis in Group 2 (2.6±0.48g/dL). Lymphocyte subset analysis showed a significant decrease in the CD8 percentage and a significant increase in CD19 percentage at diagnosis in Group 2 compared to Group 1.

CONCLUSION

The blood albumin level and the percentage of CD8 and CD19 (+) lymphocytes at diagnosis may help to predict chronic valvular disease risk in patients with acute rheumatic carditis.

Impact of MIF Gene Promoter Variations on Risk of Rheumatic Heart Disease and Its Age of Onset in Saudi Arabian Patients

Although macrophage migration inhibitory factor (MIF) has consistently been shown to be an important immune modulator, data on the association between MIF promoter variations and the risk of developing rheumatic heart disease (RHD) remain inconclusive. RHD is an important complication of streptococcal infections in the Middle East, not least in Saudi Arabia, and identifying risk markers is an important priority. Therefore, we investigated the association between two functional MIF promoter variations and RHD susceptibility and severity in Saudi patients: the MIF-173G > C substitution (rs755622) and the MIF-794 CATT5-8 tetranucleotide repeat (rs5844572). Three hundred twenty-six individuals (124 RHD patients and 202 age-, sex-, and ethnically matched healthy controls) were genotyped using allelic discrimination and fragment analysis. Data were analyzed with respect to disease susceptibility, severity, sex, and age of onset. There was a significantly lower frequency of 173C allele carriage in RHD patients compared to controls [odds ratio (OR) = 0.47; 95% confidence intervals (CIs) = 0.28-0.77; p = 0.003]. Interestingly, the 173C allele was associated with late disease onset (p = 0.001). The 794 5-repeat allele was associated with decreased RHD risk (OR = 0.56; 95% CIs = 0.38-0.82; p = 0.003). In contrast, the 794 6-repeat allele was associated with increased risk of RHD (OR = 1.7; 95% CIs = 1.2-2.5; p = 0.002). MIF promoter variations appear to have a dual role in RHD, with 173C allele non-carriers at higher risk of developing RHD at a younger age. These results require further validation in larger multi-ethnic cohorts, and functional studies are necessary to understand the underlying molecular mechanisms driving the at-risk phenotype.

Impact of V-ets Erythroblastosis Virus E26 Oncogene Homolog 1 Gene Polymorphisms Upon Susceptibility to Autoimmune Diseases: A Meta-Analysis

V-ets erythroblastosis virus E26 oncogene homolog 1 (ETS1) is recognized as a gene of risk to autoimmune diseases (ADs). Two single nucleotide polymorphisms (SNPs) in ETS1 (rs1128334 G>A and rs10893872 T>C) were considered associated with ADs risk. However, the results remain conflicting.We performed a meta-analysis to evaluate more precise estimations of any relationship. We searched PubMed, OvidSP, and Chinese National Knowledge Infrastructure databases (papers published prior to September 12, 2014) and extracted data from eligible studies. Meta-analysis was performed using the STATA 12.0 software. Random effect model or fixed effect model were chosen according to the study heterogeneities.A total of 11 studies including 7359 cases (9660 controls) for rs1128334 and 8 studies including 5419 cases (7122 controls) for rs10893872 were involved in this meta-analysis. Overall, our results showed that there were significant associations for rs1128334 with AD risk in 5 genetic models, both in pooled analysis and in systemic lupus erythematous (SLE) subgroup, and in 3 genetic models of the uveitis subgroup. Although for rs10893872, the results showed that there were significant associations in allele model both in pooled analysis and in SLE subgroup. As a conclusion, this meta-analysis demonstrated that these 2 SNPs (rs1128334 and rs10893872) in ETS1 were associated with ADs risk.

Meta-analysis of microRNA-146a rs2910164 G>C polymorphism association with autoimmune diseases susceptibility, an update based on 24 studies

BACKGROUND

Published data showed that the susceptibility of autoimmune diseases (ADs) was associated with the polymorphism rs2910164 in microRNA-146a (miR-146a). However, the results remain controversial so far. Two meta-analyses published in 2013 and 2014 came to opposite conclusions. In order to derive a more precise estimation of the relationship, we performed this meta-analysis.

METHODS

We searched the PubMed, OvidSP and CNKI databases (published prior to September 8th, 2014) and extracted data from eligible studies. The procedure of meta-analysis was performed by using the Stata 12.0 software. Random effect model or fixed effect model were chosen respectively, according to the between study heterogeneities.

RESULTS

A total of 24 case-control studies, 11 more than previous meta-analysis on this topic, were involved. We took stratified analyses by different ethnicities and different types of diseases in different genetic models. In Caucasian subgroup, significant increased risks of GC genotype and GC+CC genotype with ADs susceptibility were found in heterozygote model (GC vs GG, OR = 1.38, 95% CI 1.04-1.83, p = 0.024) and dominant model (GC+CC vs GG, OR = 1.37, 95% CI 1.01-1.85, p = 0.041), respectively. Meanwhile, in other disease subgroup, significant increased risks of C allele, CC genotype and GC+CC genotype were found in allele model (C vs G, OR = 1.16, 95% CI 1.04-1.31, p = 0.010), homozygote model (CC vs GG, OR = 1.42, 95% CI 1.10-1.84, p = 0.006) and dominant model (GC+CC vs GG, OR = 1.25, 95% CI 1.04-1.51, p = 0.020), respectively.

CONCLUSIONS

MiR-146a rs2910164 G>C polymorphism was associated with the susceptibility of ADs.

Lack of association between the CDH1 polymorphism and gastric cancer susceptibility: a meta-analysis

E-Cadherin (CDH1) plays a key role in cell adhesion, which is vital to the normal development and maintenance of cells. Down regulation of CDH1, may lead to dysfunction of the cell-cell adhesion system, resulting in increased susceptibility to tumor development and subsequent tumor cell invasion and metastasis. The CDH1 C-160A polymorphism could decrease its transcription efficiency and may increase susceptibility to cancer development, but its relevance to gastric cancer is generally disputed. Consequently, we performed a meta-analysis of published case-control studies, including 4218 gastric cancer cases and 5461 controls. Overall, no significant association was observed between the CDH1 C-160A polymorphism and risk of gastric cancer in all genetic models. In the stratified analysis by total sample size, a significant association was observed in the small sample size subgroup (total sample size < 300), but the results should be interpreted with caution. In conclusion, this meta-analysis failed to confirm the association between the CDH1 C-160A polymorphism and risk of gastric cancer. Large-scale and well-designed studies are needed to confirm our findings.