Lack of association among TNF-α gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Low levels of TNFA gene expression seem to favor the development of pulmonary tuberculosis in a population from the Brazilian Amazon

TNF-α is a Th1 cytokine profile active in the control of Mycobacterium tuberculosis infection, IL-10 is associated with persistence of bacterial infection. The aim of the study was to investigate the association of TNFA -308G/A and IL10 -819C/T polymorphisms and TNFA and IL10 gene expression levels with pulmonary and extrapulmonary tuberculosis (n = 200) and control (n = 200). The individuals were submitted to genotyping and quantification of gene expression performed by real-time quantitative polymerase chain reaction (qPCR). No association was observed between the frequencies of polymorphisms evaluated and pulmonary tuberculosis. The frequency of polymorphic genotypes for TNFA -308G/A were associated with the extrapulmonary tuberculosis (p = 0.0445). The levels of TNFA expression were lower in the pulmonary tuberculosis group than in the control (p = 0.0009). There was a positive correlation between the levels of TNFA and IL10 in patients with pulmonary tuberculosis (r = 0.560; p = 0.0103). Reduced levels of TNFA expression may promote the formation of an anti-inflammatory microenvironment, favoring the persistence of the bacillus in the host, contributing to the establishment of pulmonary tuberculosis.

Transcriptional alteration of genes linked to gastritis concerning Helicobacter pylori infection status and its virulence factors

BACKGROUND

Helicobacter pylori infection and heterogeneity in its pathogenesis could describe diversity in the expression of inflammatory genes in the gastric tissue. We aimed to investigate transcriptional alteration of genes linked to gastritis concerning the H. pylori infection status and its virulence factors.

METHODS AND RESULTS

Biopsy samples of 12 infected and 12 non-infected patients with H. pylori that showed moderate chronic gastritis were selected for transcriptional analysis. Genotyping of H. pylori strains was done using PCR and relative expression of inflammatory genes was compared between the infected and non-infected patients using relative quantitative real-time PCR. Positive correlations between transcriptional changes of IL8 with TNF-α and Noxo1 in the infected and TNF-α with Noxo1, MMP7, and Atp4A in the non-infected patients were detected. Six distinct genotypes of H. pylori were detected that showed no correlation with gender, ethnicity, age, endoscopic findings, and transcriptional levels of host genes. Irrespective of the characterized genotypes, our results showed overexpression of TNF-α, MMP7, Noxo1, and ATP4A in the infected and IL-8, Noxo1, and ATP4A in the non-infected patients.

CONCLUSIONS

A complexity in transcription of genes respective to the characterized H. pylori genotypes in the infected patients was detected in our study. The observed difference in co-regulation of genes linked to gastritis in the infected and non-infected patients proposed involvement of different regulatory pathways in the inflammation of the gastric tissue in the studied groups.

The high-dose amoxicillin-proton pump inhibitor dual therapy in eradication of Helicobacter pylori infection

INTRODUCTION

More attention has been paid to the eradication therapy of Helicobactor pylori with the enhancement of health awareness of patients. However, the increasing antibiotic resistance of H. pylori, due to the wide use and abuse of antibiotics, has become a critical factor affecting the efficacy of eradication. To effectively improve the eradication rate of H. pylori, high-dose amoxicillin-proton pump inhibitor (PPI) dual therapy has recently become one of the hot issues.

AREAS COVERED

The authors review the schemes and efficacy of high-dose amoxicillin-PPI dual therapies in eradication of H. pylori infection. The review indicates that the H. pylori eradication rate of the dual therapy is overall comparable to or better than that of bismuth-containing quadruple therapy or standard triple therapy. It is more effective to administer both amoxicillin and PPI 3-4 times daily for 14 days in the high-dose amoxicillin-PPI dual therapy, and esomeprazole seems to be superior to other PPIs.

EXPERT OPINION

The high-dose amoxicillin-PPI dual therapy is currently a promising H. pylori eradication regimen in clinical practice, deserving further verification and discussion. Much more attention should be paid to the influence of CYP2C19 polymorphisms and virulence genotyping on H. pylori eradication, and the homogeneity and objectivity of the comparison among different studies.

The impact of host's genetic susceptibility on Helicobacter pylori infection in children

The aim of our study was to investigate the impact of interleukin (IL)-6 190C/T, IL-6 174G/C, IL-6 572G/C, tumor necrosis factor-alpha (TNF-α) 308G/A, and angiotensin-converting enzyme (ACE) I/D gene polymorphisms on Helicobacter pylori (H. pylori) infection in children.A cross-sectional study was performed on 126 children (57 children with H. pylori infection and 69 children without H. pylori infection) aged between 3 and 18 years presenting to a Pediatrics Tertiary Hospital from Romania. Children were assessed clinically, endoscopically, histopathologically, and genetically.In our study, we found that the presence of the CT and CT+TT genotypes of IL-6 190C/T (P < .002 and P = .04), allele G of IL-6 572 G/C polymorphism (P = .01), genotypes GA and AA of TNF-α 308 G/A polymorphism (P = .04, P = .01), and genotype II of ACE I/D polymorphism (P = .02) were associated with H. pylori infection, while the CC genotype of IL-6 174G/C polymorphism was scarcely encountered in children with H. pylori infection [P = .02, odds ratio (OR) = 0.06; 95% confidence interval (95% CI): 0.003-0.128]. Taking under consideration the 4 variant genotypes (IL-6 572G/C, IL-6 190C/T, TNF-α 308G/A, and ACE I/D), we noticed a 2 times higher incidence of H. pylori infection (OR = 6.34; 95% CI: 2.15-25.8).We may consider that the IL-6 190C/T, IL-6 174G/C, IL-6 572G/C, TNF-α 308G/A, and ACE I/D gene polymorphisms may increase the children's susceptibility for acquiring H. pylori infection; therefore, they may contribute to the pathogenesis of H. pylori gastritis.

Genetic association between TNF-α promoter polymorphism and susceptibility to squamous cell carcinoma, basal cell carcinoma, and melanoma: A meta-analysis

Tumor necrosis factor-alpha (TNF-α) is a multifunctional pro-inflammatory cytokine that plays an important role in cancer development. We performed a meta-analysis to assess the relationship between single nucleotide polymorphisms in the TNF-α promoter region (rs1800629 and rs361525) and susceptibility to squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and melanoma. After database retrieval, article selection, data extraction, and quality assessment, 20 articles comprising 4865 cases and 6329 controls were included in this study. rs1800629 was associated with an increased overall risk of SCC, lung SCC, and oral SCC in the AA vs G and AA vs GG+GA genetic models (all OR>1, P_association<0.05). No increased risk of skin SCC, skin BCC or melanoma was observed (all P_association>0.05). Rs361525 was not associated with overall SCC risk in the allele, heterozygote, dominant, recessive, or carrier model (all P_association>0.05). Begg's and Egger's tests (P_Begg>0.05; P_Egger>0.05) demonstrated there was no significant publication bias. These data indicate that the AA genotype of TNF-α rs1800629, but not rs361525, is associated with an increased risk of SCC, suggesting it could potentially serve as a prognostic marker for predicting SCC risk.

Interleukin 8 (-251 T>A) polymorphism in children and teenagers infected with Helicobacter pylori

Background

Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the human stomach and causes a variety of gastric diseases. This study evaluated the correlations between the -251 (T>A) (rs4073) polymorphism of interleukin-8 (IL-8), the etiology of gastric disease, and H. pylori infection in pediatric and adolescent patients.

Methods

DNA samples were obtained from 285 gastric biopsies from pediatric patients. H. pylori was detected by PCR, whereas PCR-RFLP was used to characterize the -251 (T>A) polymorphism of IL-8.

Results

The histological analysis revealed the presence of gastritis in 158 patients (55.44%). H. pylori was found in 71 samples (24.9%). The -251 (T>A) polymorphism revealed that 58 (29.47%) samples were TT, 143 (50.18%) samples were TA, and 84 (20.35%) samples were AA.

Conclusions

Our findings suggest that IL8-251 A allele may be an important risk factor for the development of gastric disease when associated with H. pylori infection.

Virulence factors and pathogenic mechanism of Helicobacter pylori

Helicobacter pylori (H. pylori) is closely related with some diseases such as chronic gastritis, peptic ulcer, gastric mucosa associated lymphoid tissue lymphoma, and gastric cancer. The pathogenicity of H. pylori mainly relies on its flagellum, spiral structure, lipopolysaccharide, cytotoxin associated protein A, and vacuolating cytotoxin A. Through complex pathogenic mechanisms, H. pylori causes various kinds of diseases. In this paper, we discuss the latest research progress in the understanding of the virulence factors and pathogenic mechanism of H. pylori.