Sérgio A. Batista

Higher number of Helicobacter pylori CagA EPIYA C phosphorylation sites increases the risk of gastric cancer, but not duodenal ulcer

BackgroundHelicobacter pylori infection is one of the most common infections worldwide and is associated with gastric cancer and peptic ulcer. Bacterial virulence factors such as CagA have been shown to increase the risk of both diseases. Studies have suggested a causal role for CagA EPIYA polymorphisms in gastric carcinogenesis, and it has been shown to be geographically diverse. We studied associations between H. pylori CagA EPIYA patterns and gastric cancer and duodenal ulcer, in an ethnically admixed Western population from Brazil. CagA EPIYA was determined by PCR and confirmed by sequencing. A total of 436 patients were included, being 188 with gastric cancer, 112 with duodenal ulcer and 136 with gastritis.ResultsThe number of EPIYA C segments was significantly associated with the increased risk of gastric carcinoma (OR = 3.08, 95% CI = 1.74 to 5.45, p < 10-3) even after adjustment for age and gender. Higher number of EPIYA C segments was also associated with gastric atrophy (p = 0.04) and intestinal metaplasia (p = 0.007). Furthermore, patients infected by cag A strains possessing more than one EPIYA C segment showed decreased serum levels of pepsinogen I in comparison with those infected by strains containing one or less EPIYA C repeat. Otherwise, the number of EPIYA C segments did not associate with duodenal ulcer.ConclusionsOur results demonstrate that infection with H. pylori strains harbouring more than one CagA EPIYA C motif was clearly associated with gastric cancer, but not with duodenal ulcer.Higher number of EPIYA C segments was also associated with gastric precancerous lesions as demonstrated by histological gastric atrophic and metaplastic changes and decreased serum levels of pepsinogen I.

A regulatory instead of an IL-17 T response predominates in Helicobacter pylori-associated gastritis in children

Th17 cells seem to have an important role in the efficacy of vaccines against Helicobacter pylori. Because children are a target group for human vaccination and Th17/T(reg) cells have intrinsically linked and antagonic commitments, we compared the gastric levels of Th17- and T(reg)-associated cytokines of children and adults. IL-6, IL-10 and TGF-β1 levels and Foxp3(+) cell numbers were higher, but IL-1β, IL-17A and IL-23 were lower in infected children than in infected adults. In conclusion T(reg) instead of Th17 cell response to H. pylori-infection predominates in children.

Higher frequency of cagA EPIYA-C Phosphorylation Sites in H. pylori strains from first-degree relatives of gastric cancer patients

BackgroundTo evaluate the prevalence of more virulent H. pylori genotypes in relatives of gastric cancer patients and in patients without family histories of gastric cancer.MethodsWe evaluated prospectively the prevalence of the infection by more virulent H. pylori strains in 60 relatives of gastric cancer patients comparing the results with those obtained from 49 patients without family histories of gastric cancer. H. pylori status was determined by the urease test, histology and presence of H. pylori ureA. The cytotoxin associated gene (cagA), the cagA-EPIYA and vacuolating cytotoxin gene (vacA) were typed by PCR and the cagA EPIYA typing was confirmed by sequencing.ResultsThe gastric cancer relatives were significant and independently more frequently colonized by H. pylori strains with higher numbers of CagA-EPIYA-C segments (OR = 4.23, 95%CI = 1.53–11.69) and with the most virulent s1m1 vacA genotype (OR = 2.80, 95%CI = 1.04–7.51). Higher numbers of EPIYA-C segments were associated with increased gastric corpus inflammation, foveolar hyperplasia and atrophy. Infection by s1m1 vacA genotype was associated with increased antral and corpus gastritis.ConclusionsWe demonstrated that relatives of gastric cancer patients are more frequently colonized by the most virulent H. pylori cagA and vacA genotypes, which may contribute to increase the risk of gastric cancer.

CagA-positive Helicobacter pylori strain containing three EPIYA C phosphorylation sites produces increase of G cell and decrease of D cell in experimentally infected gerbils (Meriones unguiculatus)

PURPOSE Human infection by Helicobacter pylori is associated with an increase in the number of gastrin-producing G cells and a concomitant decrease of somatostatin-producing D cells. However, to our knowledge, changes in G and D cell numbers in response to infection with H. pylori CagA-positive strains containing different number of EPIYA-C phosphorylation sites have not been analyzed to date. Therefore, the aim of this study was to perform a quantitative analysis of the number of G and D cells in Mongolian gerbils challenged with H. pylori strains with different numbers of EPIYA-C motifs. MATERIALS AND METHODS Mongolian gerbils were inoculated with isogenic H. pylori strains containing one to three phosphorylation sites. Mucosal fragments were evaluated by morphometry and immunohistochemistry using primary polyclonal rabbit anti-gastrin and anti-somatostatin antibodies. Positive cells were counted using an image analyzer. RESULTS Forty-five days after infection, there was a decrease in the number of D cells and an increase in the G/D cell ratio in the group with three EPIYA-C. Six months after infection, there was a progressive and significant increase in the number of G cells and in the G/D cell ratio, with a concomitant decrease in the number of D cells, especially in the three EPIYA-C group. CONCLUSIONS CagA-positive H. pylori strains containing a large number of EPIYA-C phosphorylation sites induce a decrease in D cell number and an increase in G cell number and G/D ratio, which were correlated with the number of inflammatory cells of the lamina propria.

CagA phosphorylation EPIYA-C motifs and the vacA i genotype in Helicobacter pylori strains of asymptomatic children from a high-risk gastric cancer area in northeastern Brazil

Helicobacter pylori infection is one of the most common infections worldwide and is associated with gastric diseases. Virulence factors such as VacA and CagA have been shown to increase the risk of these diseases. Studies have suggested a causal role of CagA EPIYA-C in gastric carcinogenesis and this factor has been shown to be geographically diverse. We investigated the number of CagA EPIYA motifs and the vacA i genotypes in H. pylori strains from asymptomatic children. We included samples from 40 infected children (18 females and 22 males), extracted DNA directly from the gastric mucus/juice (obtained using the string procedure) and analysed the DNA using polymerase chain reaction and DNA sequencing. The vacA i1 genotype was present in 30 (75%) samples, the i2 allele was present in nine (22.5%) samples and both alleles were present in one (2.5%) sample. The cagA-positive samples showed distinct patterns in the 3’ variable region of cagA and 18 of the 30 (60%) strains contained 1 EPIYA-C motif, whereas 12 (40%) strains contained two EPIYA-C motifs. We confirmed that the studied population was colonised early by the most virulent H. pylori strains, as demonstrated by the high frequency of the vacA i1 allele and the high number of EPIYA-C motifs. Therefore, asymptomatic children from an urban community in Fortaleza in northeastern Brazil are frequently colonised with the most virulent H. pylori strains.

Higher Frequency of CagA EPIYA-C Phosphorylation Sites in H. pylori Strains From Relatives of Gastric Cancer Patients

Background and aims:Helicobacter pylori dupA (duodenal ulcer promoting) gene was reported as a virulence factor that induced duodenal ulcer and had a suppressive action on gastric cancer. However, the association of the dupA gene on clinical outcomes is different in different populations. Full-sequenced data of H. pylori showed that the length of the dupA gene is depends on the strain; Shi470 and G27 have approximately 600bp longer than that of other strains (e.g., strain J99) in the C-terminal region of the dupA gene. This suggests that the dupA gene has two genotypes: long and short type. In addition, previous studies indicated that some strains have a presence of the mutation (insertion or mutation) in the dupA gene, which created a premature stop codon . In this study, we aimed to examine the dupA genotypes (long type or short type), presence of the mutation, and examined the association with clinical outcomes in Japanese population. Methods: A total of 388 patients (97 with gastritis, 137 with duodenal ulcer [DU], 121 with gastric ulcer [GU], and 24 with gastric cancer [GC]) were included in this study. The status of the dupA genes was examined by polymerase chain reaction. The oligonucleotide primers for the dupA typing were designed according to the dupA gene sequence deposited in Genbank. First primers were designed to include the additional region of C-terminal of the dupA gene (long type dupA). Second primers were designed to include the conventional dupA gene (short type dupA). We also sequenced full-length dupA gene and evaluated the presence of mutation. Results: The prevalence of short type dupA gene alone was not significantly different among four groups (gastritis 14.4%, DU 8.0%, GU 6.5%, and GC 4.2%, respectively). Interestingly, the prevalence of the long type dupA gene in strains from DU was significantly higher than that from gastritis (19.7 v.s. 9.3%, p = 0.02). Those of GU, GC were also significantly higher than that of gastritis (25.8, 25.0 and 9.3%, p = 0.0001, p = 0.03, respectively). Full-length sequence of the dupA gene was completed in 33 strains. Among them, point mutation lead to stop codon was found in only one strain. Conclusions: The long type but not the short type dupA gene can be used as discriminating factor of peptic ulcer and gastric cancer from gastritis in Japan. These observations suggest that only strains that are intact dupA-positive might be involved in gastroduodenal diseases.

T1637 Gastric Carcinoma Patients Have a Specific Cytokine Profile Characterized By Strongly Increased Levels of Treg Cytokines, IL-1β, IL-6, IL-8 and IL-23 and Decreased Levels of IL-1α, IL-12p70, IFN-γ and TNF-α

G A A b st ra ct s a significant increase in PELI1 mRNA expression. PELI1 knock-down inhibited TLR2mediated activation of NF-κB and the IL-8 promoter in response to Pam2CSK4 and H. pylori LPS. Conversely, TRIB3 knock-down enhanced NF-κB and IL-8 promoter activity in response to Pam2CSK4 and H. pylori LPS. Furthermore, over-expression of TRIB3 resulted in a dose dependent inhibition of the activating properties Pam2CSK4 and H. pylori LPS. Conclusions: PELI1 positively regulates TLR2-mediated signaling in response to H. pylori LPS, while TRIB3 has a negative effect. Further studies are required to investigate the expression of these proteins in gastric epithelial cells from H. pylori-infected patients. By identifying new regulators of H. pylori-induced cell signaling events, potential therapeutic targets to treat H. pylori-associated disease may be revealed.