Cytotoxin and urease activities of Helicobacter pylori isolates from Japanese patients with atrophic gastritis or duodenal ulcer

Abstract

The vacuolating cytotoxin and urease secreted by Helicobacter pylori are thought to be virulent factors. Because vacuolation is potentiated by the presence of ammonium ion, which is produced by urease in vitro, it is of interest to examine whether cytotoxin and urease work reciprocally in the development of atrophic gastritis or duodenal ulcer. In the present study, patients (all H. pylori-positive) were divided into four groups: mild atrophic gastritis (group 1; nine patients), severe atrophic gastritis (group 2; 36 patients), duodenal ulcer with mild atrophic gastritis (group 3; 19 patients) and duodenal ulcer with severe atrophic gastritis (group 4; 12 patients). Cytotoxin production and urease activity of H. pylori isolated from these patients were analysed. Cytotoxin production was observed in four of nine (44.4%), 28 of 36 (77.8%), 11 of 19 (57.9%) and eight of 12 (66.7%) isolates from groups 1, 2, 3 and 4, respectively. Cytotoxin-producing H. pylori isolates were found significantly more in patients with severe atrophy than in patients with mild atrophy (P = 0.048). The mean of relative activity of cytotoxin in H. pylori isolate was 1.6 +/- 2.3, 7.9 +/- 7.4, 5.8 +/- 6.0 and 9.0 +/- 9.1 in groups 1, 2, 3 and 4, respectively. Helicobacter pylori isolates from severe atrophy or duodenal ulcer patients in groups 2 or 4 possessed significantly higher activity than those from non-ulcer patients in group 1 (P = 0.017 and 0.030, respectively). The mean of urease activity was 8.6 +/- 4.6, 10.0 +/- 5.9, 10.0 +/- 8.5 and 11.2 +/- 7.7 IU/mg in groups 1, 2, 3 and 4, respectively. These differences indicated no statistical significance. In each H. pylori isolate, the production of cytotoxin and urease were independent, which indicated that there was no reciprocal effect between them in vivo. Thus, cytotoxin-producing H. pylori isolates were more prevalent in patients with severe atrophic gastritis and the cytotoxin activities of H. pylori isolates from the patients with severe atrophic gastritis or duodenal ulcer were much higher than those from the patients with mild atrophic gastritis, which suggested that vacuolating cytotoxin may be a disease-inducing factor.

Serological response to Helicobacter pylori recombinant antigens in Chilean infected patients with duodenal ulcer, non‐ulcer dyspepsia and gastric cancer

“…These results are similar to those of Graham et al (17) and Kodama et al (18), but disagree with other results (1 1, 14, 15, 49, 50) which show a significant association between these antigens and duodenal ulcer. Similarly, we have found no links between CagA or VacA and gastric cancer, in contrast to previous studies on different H. pylori-infected populations respecting CagA (19)(20)(21)(22) and VacA (25,26). However, results similar to ours have been reported by other authors (23, 24).…”

“…In contrast, Perez-Perez et al (23) and Mitchell et al (24) failed to show any correlation between gastric cancer rates and prevalence of CagA+ infection, including Western and Eastern countries. Regarding the VacA antigen, cytotoxinproducing H. pylori isolates were found more frequently in patients with severe atrophic gastritis, an early stage during the development of gastric cancer, than in patients with mild atrophy (25). Also, high prevalence of neutralizating activity to H. pylori cytotoxin has been found in serum of gastric carcinoma patients (26).…”

Analysis and typing of the vacA gene from cagA-positive strains of Helicobacter pylori isolated in Japan

“…The histological atrophy of the antrum and the endoscopic atrophy assessed by these criteria are positively correlated (12). Atrophy with patterns C-I and C-II was defined as mild, while atrophy with patterns C-III, O-I, O-II, and O-III were defined as severe (19). Of 40 patients with chronic atrophic gastritis, 17 (mean age, 49.4 Ϯ 13.5 years) had mild atrophy.…”

“…The prevalence of both gastric cancer and atrophic gastritis is extremely high in Japan (17,21,24). We have reported previously that tox ϩ H. pylori isolates were more prevalent in patients with severe atrophic gastritis and that the cytotoxin activities in H. pylori isolates from patients with severe atrophic gastritis were much higher than those from patients with mild atrophic gastritis in Japan (19). The lineage of H. pylori isolates infecting Japanese subjects may be different from that of isolates in other parts of the world or a specific strain may have accumulated in the Japanese population.…”

Proteomic Helicobacter pylori biomarkers discriminative of low‐grade gastric MALT lymphoma and duodenal ulcer

“…UreA is mainly found in the cytoplasm 40, 41, but it is also present at the cell surface and can be released by the bacterium 42. Murikita et al did not find any difference in urease activity between strains associated with atrophic gastritis or DU 43. Ito et al .…”