Association among H. pylori virulence markers dupA, cagA and vacA in Brazilian patients

Background:Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pyloriappear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor ofHelicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence ofdupA gene and evaluate the association amongdupA and other virulence factors includingcagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.Results:Patients with gastritis tested positive for H. pylori more frequently. The dupA gene was detected in 41.5% of them (85/205); cagA gene was found in 98 isolates (47.8%) andvacA genotype s1/m1 in 50.2%, s1/m2 in 8.3%, s2/m2 in 36.6%, s2/m1 in 0.5% and s1/s2/m1/m2 in 4.4%. We also verified a significant association between cagA and dupA genes [p = 0.0003, relative risk (RR) 1.73 and confidence interval [CI] = 1.3-2.3]. The genotypes s1/m1 were also associated with dupA gene (p = 0.0001, RR: 1.72 and CI: 1.3-2.2). The same associations were found when analyzing pediatric and adult groups of patients individually.Conclusion:Ours results suggest that dupA is highly frequent in Brazilian patients and is associated with cagA gene andvacA s1/m1 genotype, and it may be considered an important virulence factor in the development of gastric diseases in adults or children

Expression of miRNA-146a, miRNA-155, IL-2, and TNF-alpha in inflammatory response to Helicobacter pylori infection associated with cancer progression

miRNAs appear to play an important role in controlling the expression of several genes, and they are a potential biomarker and prognostic tool in gastric diseases. We analyzed 53 controls, 86 patients with gastritis, and 19 patients with gastric cancer. Real-time-PCR was used to determine the expression levels of miRNA-146a, miRNA-155, IL-2, and TNF-. The subsequent analysis of the target genes was performed using the bioinformatics approach. There was no difference in IL-2 expression between the groups. However, there was a significant increase in TNF- expression in the gastritis group relative to the control and a significant decrease in the gastric cancer group relative to the control. There was also a statistically significant increase in miRNA-146a and miRNA-155 expression in the gastritis group relative to the control, but not in the gastric cancer group. Similar results were found when the presence of H. pylori was considered. The data revealed an increase in miRNA-146a and miRNA-155 expression but not enough to control the expression of TNF-. The presence of H. pylori was found to affect increases in TNF- and microRNA expression, and miRNA-146a and miRNA-155 alone were not able to eliminate bacteria or restore tissue homeostasis.Sao Paulo Research FoundationUniversidade do Sagrado Coração (USC), Bauru, Sao Paulo, BrazilUniv Fed Sao Paulo UNIFESP, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Sao Paulo, SP, BrazilFAPESP: 2015/11371-5FAPESP: 2015/11613-9Web of Scienc