Increased expression of interleukin-6 gene in gastritis and gastric cancer

Helicobacter pylori (H. pylori) induces an intense inflammatory response, mediated by proinflammatory cytokines, including interleukin (IL)-6 and its membrane receptor (IL-6R), which activates important signaling pathways in the development of gastric disease and cancer. We investigated the gene and protein expression of IL-6 and IL-6R and the influence of polymorphisms rs1800795, rs1800796, and rs1800797 on its gene expression together with H. pylori infection. Furthermore, an in-silico analysis was performed to support our results. Gastric biopsies were obtained from patients with gastric symptoms and patients with gastric cancer (GC) and were divided into groups (Control, Gastritis, and Cancer). H. pylori was detected by PCR. Real-time-qPCR was employed to determine gene expression, and western blot assay was used to analyze protein expression levels. PCR-RFLP was used to characterize IL-6 polymorphisms. Bioinformatics analyses were performed using the Gene Expression Omnibus (GEO) database and GEO2R to screen out differentially expressed genes (DEGs). H. pylori was detected in 43.3% of the samples. Statistically significant differences were found for IL-6 (P=0.0001) and IL-6R (P=0.0005) genes among the three groups, regardless of the presence of H. pylori. Among patients with H. pylori infection, the IL-6 and IL-6R gene and protein expressions were significantly increased, highlighting IL-6 gene overexpression in patients with GC. No statistically significant differences were found for the rs1800795, rs1800796, and rs1800797 polymorphisms compared to IL-6 gene expression. The results indicated that the IL-6 polymorphisms do not influence its expression, but IL-6 and IL-6R expression seems to be altered by the presence of H. pylori.

Detection of Helicobacter pylori in gastric biopsies, saliva and dental plaques of dyspeptic patients from Marília, São Paulo, Brazil: presence of vacA and cagA genes

Helicobacter pylori, a gram-negative bacterium, possesses two important virulence factors: the vacuolating toxin (vacA), and the cytotoxin-associated gene product (cagA). The aim of the present study was to evaluate the presence of H. pylori in the stomach and oral cavity of humans and compare the cagA and vacA genotypes of H. pylori found in different samples (stomach, saliva and dental plaque) from the same patient. Gastric biopsies, saliva and dental plaques were obtained from 62 dyspeptic adults. DNA was extracted and evaluated for the presence of H. pylori and the alleles cagA and vacA. Persons with gastritis had a higher frequency of H. pylori -positive samples in the stomach while positive samples from gastric biopsies were significantly correlated with those from the oral cavity. There was a high H. pylori frequency in patients while the cagA gene was associated with vacA s1 alleles in gastric biopsies. Our results suggest a reservoir of the species in the oral cavity and that, in one patient, more than one H. pylori strain may exist in the saliva, dental plaque and stomach. We found a relationship between gastric infection and the bacterium in the oral cavity, with the cytotoxin genotype varying between saliva and dental plaque.(AU)

Relationship between Helicobacter pylori detection and an increased risk of infection in childhood

The risk of developing gastric cancer is believed to be related to differences among Helicobacter pylori strains and the inflammatory responses mediated by host genetic factors. H. pylori infection is acquired at an early age and in the absence of appropriate antibiotic therapy, it generally persists for life. Tp53 gene regulates the transcription of several cytokines and chemokines involved in innate immunity and its action may be influenced by the presence of different H. pylori strains. The present study aimed to detect H. pylori in pediatric patients, to access Tp53 polymorphism at codon 72 and to correlate such findings with age and histopathological results. Three hundred and forty-two patients were analyzed. DNA from their gastric biopsies was extracted and the detection of H. pylori was performed through polymerase chain reaction assays, urease test and histopathologic examination. Allelic discrimination of SNP rs1042522 (Tp53) was performed by real-time polymerase chain reaction. Our results suggest a possible relationship between the presence of H. pylori and chronic gastritis in children and young patients, and showed a significant association between ageing and positivity for H. pylori. It was verified that patients aged < 10 years were 1.3 times more likely to have infection by H. pylori when compared with those aged > 10 years. Finally, no association was found between Tp53 polymorphisms and the presence of H. pylori.