Helicobacter pylori infection density and gastric inflammation in duodenal ulcer and non-ulcer subjects.

Abstract

The factors that determine which Helicobacter pylorn infected subjects develop duodenal ulcer (DU) are unclear. This study tested the hypothesis that infection density and urease activity are higher in DU than non-DU subjects. Fifty five DU and 55 age and sex matched non-DU subjects were studied. Quantitative methods were used for measuring infection density (viable organism count) and urease activity (Berthelot reaction). DU subjects had a greater antral infection density ( Studies have attempted to explain the outcome of H pylori infection on the basis of differences in strain virulence.6-8 A cytotoxin obtained from some strains of H pylori has been shown to produce vacuolation in cultured cell lines.9 The association between DU and carriage of cytotoxic strains of H pylori is strong, however, such strains also occur in most subjects without DU7 and therefore can only provide part of the explanation for the development of ulceration.H pylori produces large amounts of urease, the ammonia generated by this has been shown to have cytopathic effects on different cultured cell lines in a concentration dependent manner,10 11 and to be toxic to the gastric mucosa of experimental animals.'2 It is possible that strains of H pylori associated with ulceration produce greater amounts of urease.Histological assessment of the distribution and density of H pylori in the stomach has suggested that there may be greater colonisation of the gastric antrum in DU patients than subjects without DU,13 however, one study has produced conflicting results, showing no significant difference between the two groups. 14 The patchy nature of the distribution of the organism and the tendency of H pylori to colonise gastric glands in large clumps renders semi-quantitative histological studies inadequate for the measurement of a potentially immense range of infection densities in vivo. In addition, no assessment of organism viability is possible on histological sections.In this study we aimed to assess by quantitative methods H pylori infection density and urease activity in patients with DU and in those without; and the relation of infection density to factors associated with DU.

Helicobacter pylori infection and gastric mucosal epithelial cell apoptosis

“…Consistent with the fact that H. pylori colonization is greater in the antrum versus the gastric body (140,141), the extent of expression of both iNOS and COX-2 has been seen to also be considerably higher in the antrum. However, it should be noted that a recent study showed inflammation levels that were not significantly higher in the antrum versus the gastric body, which suggests a direct effect of H. pylori on the induction of expression for both genes (116).…”

Association between Helicobacter pylori concentration and the combining frequency of histopathological findings in gastric biopsies specimens

“…In our study, the presence of activity was even more frequent in the cases negative for bacteria (72.3%) than in H. pylori positive cases (53%), as observed in PHULL et al study (17) . Some authors have been reporting a association between the activity grade and the bacterial concentration (1,6,11,12,20) although some of them have reported that only this finding could have an association with the concentration of H. pylori (12,20) . Although in our study the incidence of activity was higher in biopsy specimens without the bacterium, their marked activity prevailed over the biopsy specimens that had a concentration of bacteria of 3+ (42%).…”

“…Since it was firstly described by Warren and Marshall in 1983, Helicobacter pylori (H. pylori) etiologic relevance has been emphasized (17,18) in many gastrointestinal tract and esophageal diseases as being reported to cause gastritis, peptic ulcers, dysplastic lesions, gastric adenocarcinoma, gastric lymphomas (7,8,12,14,17,19,22) and a possibly cause of non-ulcer dyspepsia (7) . In developing countries, the infection is acquired during childhood, compromising around 90% of the population.…”

“…Some studies have shown an association between H. pylori concentration and the gastritis severity and activity score (1,6,7,11,12,20) . The aim of this study was to investigate the association between H. pylori concentration and the combining frequency of histopathological findings in gastric biopsies.…”

Identificação do Helicobacter pylori pela citologia do escovado gástrico: comparação com o método histológico

“…Cerca de 27 casos positivos pelo método citológico foram negativos pela histologia: a escova de citologia abrange uma área maior a ser estudada e estes dados sugerem ser a citologia mais sensível que os métodos que se utilizam de biópsia na identificação do Helicobacter pylori. O microrganismo está distribuído irregularmente no muco gástrico na superfície epitelial, e a relativa baixa densidade da bactéria em vários grupos de pacientes pode levar a resultados falso-negativos em métodos de biópsia 12 . A comparação de um método que se utiliza do esfregaço obtido por um escovado gástrico -a citologia, com um método que se utiliza de biópsia -a histologia, influenciou na especificidade do primeiro que foi de 50,9%.…”