Relationship between Helicobacter pylori infection and gastric acid secretion in young healthy subjects

Influence of Helicobacter pylori infection on gastric acid secretion in pre-school Bangladeshi children

BACKGROUND

The effect of Helicobacter pylori (H. pylori) infection on gastric acid secretion (GAS) is poorly defined in children.

OBJECTIVE

To determine whether H. pylori infection is associated with abnormal GAS in children.

METHODS

We studied 30 H. pylori-infected children (identified by a positive urea breath test) and 30 noninfected children of both sexes, aged 2-5 years. Gastric pH and GAS were measured before and 8 weeks after the completion of a 2-week course of anti- H. pylori therapy (omeprazole, clarithromycin, and amoxicillin). Gastric acid output (GAO) was quantified during a 1-h basal period (GAO-B) (mmol/h) and a 1-hour stimulated period (GAO-S) (mmol/hour) following subcutaneous administration of pentagastrin (6 μg/kg).

RESULTS

A significantly greater number of infected children had a high gastric pH (>4.0, p = 0.03) compared with the noninfected group. GAO-B and GAO-S in H. pylori-infected children were significantly lower, around 50%, compared with children without H. pylori infection. H. pylori-eradication therapy resulted in a rise of both the mean GAO-B (paired t-test before vs. after therapy; 0.28 ± 0.40 vs. 0.62 ± 1.0, p = 0.12) and GAO-S (before vs. after therapy; 2.0 ± 1.4 vs. 3.4 ± 2.5, p = 0.001), with values reaching equivalence to those in the H. pylori-negative children (0.71 ± 0.56 for BAO, 3.3 ± 2.0 for SAO, p = NS).

CONCLUSION

The results suggest that the gastric barrier is compromised in children with H. pylori infection in Bangladesh. Improvement of GAO following anti- H. pylori therapy suggests a causal link between H. pylori infection and depressed GAO in this population.

Serum gastrin concentration and changes in G and D cell densities in gastric antrum in children with chronic gastritis

BACKGROUND

Elevated gastrin concentration leading to gastritis is explained as the effect of change in the density of D and G cells. The aim of the study was to determine and compare fasting serum gastrin concentrations, G and D cell densities in gastric antrum mucosa in children with chronic gastritis and in children with no gastritis or Helicobacter pylori infection.

MATERIAL AND METHODS

A total of 184 patients aged 6-18 years, with chronic abdominal pain underwent endoscopic examination. We created three groups: I--patients with chronic gastritis and H. pylori infection; II--patients with chronic gastritis but no H. pylori infection; III--patients with neither gastric mucosal abnormalities nor H. pylori infection. G and D cell densities were determined in the biopsy specimens (using Rbalpha H Gastrin & Somatostatin antibodies). Fasting serum gastrin concentrations were measured using a Beckmann gamma-counter and a GASK-PR kit.

RESULTS

The mean serum gastrin concentration in group I was higher when compared with group II (p = 0.04) and group III (p = 0.019). No statistically significant differences were found between groups II and III (p = 0.91). There were no statistically significant differences in G and D cell densities between groups.

CONCLUSION

The mean G/D cell ratios in groups I and III were almost identical. The mean fasting serum gastrin concentration was higher in children with both chronic gastritis and H. pylori infection compared with patients without infection or without antral inflammation. No difference in the G cell density or D cell density in children was found, regardless of the presence or absence of gastritis or H. pylori infection.

Helicobacter pylori infection influences the acidity in the gastric tube as an esophageal substitute after esophagectomy

It is commonly considered that acidity in a gastric tube used as an esophageal substitute after esophagectomy decreases due to truncal vagotomy. However, there have been few, if any, studies on the factors influencing the acidity in the gastric tube. It is well known that Helicobacter pylori (H. pylori) plays an important role in acid secretion of the stomach. The aim of this study was to investigate whether or not H. pylori infection also influenced the acidity in the gastric tube as an esophageal substitute. We investigated the changes in the levels of gastric acidity and the status of H. pylori infection from the preoperative period to 1 year after surgery. In 65 Japanese patients who underwent resection of esophageal cancer followed by reconstruction using a gastric tube, 24-h gastric pH monitoring and examination of H. pylori infection using the 13C-urea breath test and biopsy specimen obtained from the gastric mucosa under upper gastrointestinal endoscopy were performed pre- and postoperatively. Twenty-seven among the 65 patients underwent the same examinations at 1 year after surgery. The levels of postoperative gastric acidity and at 1 year after surgery were significantly lower than that of preoperative gastric acidity (P = 0.031, P = 0.001, respectively). There was no difference in the levels of gastric acidity between 1.5 months and 1 year after surgery (P = 0.282). The levels of gastric acidity in the stomach and in the gastric tube were significantly influenced by H. pylori infection, while age, gender, and past history of peptic ulcer showed no influence. The level of gastric acidity in patients who had H. pylori infection pre- and postoperatively were significantly lower than that in patients who had no H. pylori infection pre- and postoperatively (P < 0.0001). H. pylori infection was indicated to be an important factor influencing the levels of gastric acidity in the reconstructed esophagus as well as in the stomach before surgery.

Of blood and guts: association between Helicobacter pylori and the gastric microcirculation

The relative importance of acid in Helicobacter pylori (H. pylori) ulcer pathogenesis is in doubt, with possibilities existing that other contributing factors may be involved. Vascular insufficiency may lead to the development of ischemic lesions or ulcers within the gastric mucosa. H. pylori produces a striking inflammatory response following infection and one of the major components of gastrointestinal inflammation is alterations in the vascular structure and function. This suggests that the microcirculation may be a key target of H. pylori-released factors. Recent evidence has accumulated to suggest that H. pylori can affect a number of microcirculatory variables including blood flow, leukocyte activity and also induce changes in the endothelial lining of the vessels themselves. The majority of these findings have been described by employing the technique of fluorescent in vivo microscopy, which allows direct, dynamic and real time observations of the microcirculation to be made. A universal feature of these experimental studies has been the formation of circulating or adherent platelet aggregates. It is now recognized that platelets participate in the inflammatory response by acting as a potent source of inflammatory mediators and modulating the activity of other inflammatory cells. Circulation of platelet emboli may be of cause for concern, especially as a number of studies have demonstrated an association between H. pylori infection and coronary heart disease. The present review highlights the major findings from these studies and proposes an important role for the gastric microcirculation in the pathophysiology of H. pylori-induced injury.

Effect of age and Helicobacter pylori infection on gastric acid secretion

BACKGROUND

Whether gastric acid secretion decreases with age is still controversial. With the discovery of Helicobacter pylori, the association of this bacterium with gastric acid secretion has also been discussed. The aim of this study was to investigate the relationship between gastric acid secretion, age and H. pylori infection.

METHODS

The presence of H. pylori infection, the grade of fundic atrophic gastritis (FAG), and gastric acid secretion were investigated in 280 subjects without localized lesions in the upper gastrointestinal tract. Helicobacter pylori infection was confirmed by Giemsa and immunohistochemical staining, and FAG of biopsy specimens was graded on a scale of 0-4.

RESULTS

Both basal and maximal acid output decreased with age in H. pylori-positive subjects, while they did not change with age in H. pylori-negative subjects. Gastric acid secretion decreased with the progression of FAG. An age-correlated decrease in gastric acid secretion in H. pylori-positive subjects depended on an increasing prevalence of FAG with age.

CONCLUSIONS

In the population studied, advancing age had no influence on gastric acid secretion in H. pylori-negative subjects. Gastric acid secretion decreases with age in H. pylori-positive subjects because of the increasing prevalence of FAG with age.

Negative association between Helicobacter pylori infection and reflux esophagitis in older patients: case-control study in Japan

BACKGROUND

Recent studies have clarified a close association between H. pylori infection and gastritis, peptic ulcer disease, and gastric cancer, but there is little information concerning the relationship between H. pylori infection and reflux esophagitis (RE). We investigated the relationship between H. pylori, RE, and corpus gastritis.

SUBJECTS AND METHODS

Ninety-five patients with RE and 190 sex- and age-matched asymptomatic healthy controls demonstrating no localized lesions in the upper GI tract were studied and evaluated for H. pylori infection, histologic gastritis, serum gastrin, and pepsinogens (PGs).

RESULTS

H. pylori infection was significantly lower in RE patients than in asymptomatic controls (41% vs. 76%, p <.01). Histologic gastritis of both the antrum and corpus was significantly less frequent (antrum; p <.01, corpus; p <. 01), and serum levels of PGI and the PG I/II ratio were significantly higher in RE patients than in controls (PGI; p <.05, PG I/II ratio; p <.01). When the subjects were divided into two age groups (59 years of age and younger and 60 years of age and older), a significant difference was found only among patients over 60 years of age (29% vs. 85%, p <.01). Among subjects in this age group, gastritis in both the antrum and corpus were significantly milder in RE patients than in controls. Although the prevalence of H. pylori infection was similar between the two groups of patients under 59 years of age, corpus gastritis was significantly milder in patients than in controls (p <.05).

CONCLUSIONS

A significantly low prevalence of H. pylori infection was found in RE patients over 60 years of age but not in those under 59 in comparison with sex- and age-matched controls. The relative lack of corpus gastritis might play a role in the pathogenesis of RE in our population through preservation of the acid secretion area.

Eradication of Helicobacter pylori increases gastric acidity in patients with atrophic gastritis of the corpus-evaluation of 24-h pH monitoring

BACKGROUND

Recent studies have shown that the eradication of Helicobacter pylori results in a gastric acid secretion which decreases to normal levels in patients with duodenal ulcer disease. The aim of this study was to evaluate the effect of eradication of H. pylori in a 24-h study of gastric acidity in patients with atrophic gastritis of the corpus.

METHODS

Intragastric acidity was measured by continuous 24-h pH monitoring, and the histology of the gastric antrum and corpus were evaluated in 14 H. pylori-positive patients with histologically proven atrophic gastritis of the corpus (10 men, 4 women; mean age, 57 years) before and 1 year after anti-H. pylori therapy.

RESULTS

H. pylori was absent in 13 of 14 patients 1 year after treatment. Both gastritis and atrophy scores were significantly lower after eradication therapy (P < 0.01). The 24-h median pH and the percentage of 24-h pH readings above 4.0 units were significantly decreased after eradication therapy (from 5.12 +/- 0.36 to 2.69 +/- 0.21, and from 65.5 +/- 6.6% to 28.2 +/- 6.1%, P < 0.01, respectively.)

CONCLUSION

Eradication of H. pylori increases 24-h gastric acidity in patients with atrophic gastritis of the corpus. Improvement of the histology of the gastric antrum and corpus may lead to the normalization of gastric acidity.

Treatment with proton pump inhibitors induces tolerance to histamine-2 receptor antagonists in Helicobacter pylori-negative patients

BACKGROUND

Treatment with H2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) induces hypergastrinemia and causes rebound hypersecretion of gastric acid after treatment, and during treatment with H2RAs tolerance develops. In the present study we investigated whether a treatment period with a PPI induced tolerance to an H2RA.

METHODS

Thirteen patients with esophagitis were given omeprazole for 90 days. Twenty-four-hour pH monitorings without and with ranitidine were performed before and after treatment with omeprazole. Blood samples and biopsy specimens from the oxyntic mucosa were analyzed for gastrin, histamine, and chromogranin A.

RESULTS

An increase in mucosal histamine and a reduction in the effect of ranitidine on gastric pH was found 14 days after discontinuing omeprazole compared with before treatment in Helicobacter pylori-negative but not in H. pylori-positive patients.

CONCLUSIONS

Treatment with omeprazole reduces the effect of ranitidine in H. pylori-negative patients. This is caused by an increase in histamine released by the enterochromaffin-like cell secondarily to hypergastrinemia, corresponding to the tolerance towards H2RAs seen in patients with Zollinger-Ellison syndrome.

Effects of Helicobacter pylori on gastritis, pentagastrin-stimulated gastric acid secretion, and meal-stimulated plasma gastrin release in the absence of peptic ulcer disease

OBJECTIVE

There is strong evidence accumulating that chronic infection with Helicobacter pylori (H. pylori) interferes with inhibitory pathways of the regulation of acid secretion. The increase in maximum acid output (MAO), and the increase in the sensitivity of the parietal cell to gastrin commonly observed in patients suffering from duodenal ulcer disease (DU), however, remains largely unexplained. Insufficient evidence is available concerning how these parameters are influenced by H. pylori infection in patients not suffering from peptic ulcer disease (PUD) and how they are related to H. pylori-induced gastritis. The aim of this study was to compare basal gastric acid secretion (BAO), MAO, and the sensitivity of the parietal cell to gastrin in H. pylori-positive and H. pylori-negative patients not suffering from PUD, and to study the relationship with their individual postprandial gastrin release and the degree of gastric antral and corpus gastritis.

METHODS

H. pylori status was assessed by CLO test and histology (two biopsies each from the antrum and the corpus) in 14 H. pylori-positive and 16 H. pylori-negative nonulcer patients of comparable age, weight and gender. Gastritis score was assessed by a pathologist, who was unaware of the acid secretory data. Following determination of BAO, the relation of pentagastrin and gastric acid secretion was established with a cumulative pentagastrin dose response curve for the dose range 0.03-6.0 microg/kg(-1) h(-1) and MAO (Vmax) and pentagastrin sensitivity (ED50) were determined. Basal and postprandial gastrin release was measured by radioimmunoassay.

RESULTS

There was a significant higher gastritis score in the H. pylori-positive compared with the H. pylori-negative subjects. The dose response curves of the pentagastrin stimulated gastric acid secretion were not different between H. pylori-positive and H. pylori-negative groups. No correlation was seen between the gastritis score, basal acid output (BAO) peak acid output (PAO), maximum acid output (MAO), ED50 values and the plasma gastrin values. There was, however, a considerable larger variation of the PAO and MAO data of the H. pylori-infected subjects and >50% of the respective data was above or below the relatively low range of the respective values of the noninfected subjects.

CONCLUSIONS

H. pylori-induced gastritis does not regularly enhance maximum acid output in nonulcer patients, nor does it modify the sensitivity of the parietal cell to gastrin. H. pylori infection is thus unlikely to be directly responsible for an increase of these parameters in DU disease. Our data support, however, the concept that chronic H. pylori infection can either enhance or attenuate maximum acid secretory capacity in certain subgroups of patients.

The association between antral G and D cells and mucosal inflammation, atrophy, and Helicobacter pylori infection in subjects with normal mucosa, chronic gastritis, and duodenal ulcer

OBJECTIVE

The aim of this study was to clarify the mechanism of inappropriate hypergastrinemia in Helicobacter pylori (H. pylori)-infected subjects.

METHODS

We measured fasting serum gastrin (SG) concentrations, and investigated immunohistochemically G and D cell numbers in 47 subjects with normal mucosa, 24 subjects with chronic gastritis, and 24 subjects with duodenal ulcer (DU). The degree of inflammation and atrophy were classified into four categories based on criteria established in the Sydney System: none, mild, moderate, and severe. Avidin-biotin complex methods were used to identify G and D cells, which were counted per unit square (0.25 mm2) in five random fields from each of two well-oriented antral and fundic biopsies. SG concentrations were measured by radioimmunoassay.

RESULTS

The G cell number was not significantly different between 24 subjects with H. pylori-associated gastritis and those with DU. However, the number of antral D cells was significantly lower and the G/D cell ratio was significantly higher in subjects with DU than in those with H. pylori-associated gastritis (p < 0.01), although the degree of inflammation and atrophy in the antrum and H. pylori status were similar between the two groups. The mean fasting SG concentration was higher in subjects with DU than in those with H. pylori-associated gastritis, but the difference was not statistically significant.

CONCLUSIONS

Our results demonstrate that a marked decrease in antral D cell number with a high G/D cell ratio may contribute to hypergastrinemia and the pathogenesis of DU.

How does Helicobacter pylori cause mucosal damage? Its effect on acid and gastrin physiology

Helicobacter pylori infection increases gastric acid secretion in patients with duodenal ulcers but diminishes acid output in patients with gastric cancer and their relatives. Investigation of the basic mechanisms may show how H. pylori causes different diseases in different persons. Infection of the gastric antrum increases gastrin release. Certain cytokines released in H. pylori gastritis, such as tumor necrosis factor alpha and specific products of H. pylori, such as ammonia, release gastrin from G cells and might be responsible. The infection also diminishes mucosal expression of somatostatin. Exposure of canine D cells to tumor necrosis factor alpha in vitro reproduces this effect. These changes in gastrin and somatostatin increase acid secretion and lead to duodenal ulceration. But the acid response depends on the state of the gastric corpus mucosa. The net effect of corpus gastritis is to decrease acid secretion. Specific products of H. pylori inhibit parietal cells. Also, interleukin 1 beta, which is overexpressed in H. pylori gastritis, inhibits both parietal cells and histamine release from enterochromaffin-like cells. H. pylori also promotes gastric atrophy, leading to loss of parietal cells. Factors such as a high-salt diet and a lack of dietary antioxidants, which also increase corpus gastritis and atrophy, may protect against duodenal ulcers by decreasing acid output. However, the resulting increase of intragastric pH may predispose to gastric cancer by allowing other bacteria to persist and produce carcinogens in the stomach.

Antigastric autoantibodies in Helicobacter pylori gastritis: prevalence, in-situ binding sites and clues for clinical relevance

Colonization of human gastric mucosa with Helicobacter pylori leads to chronic active gastritis and induces the occurrence of an acquired mucosa-associated lymphoid tissue (MALT) in the stomach. This remodelling of the gastric mucosa together with chronic antigen persistence may induce autoimmune reactions. The aim of this study was to investigate humoral autoimmune reactions to human gastric mucosa in H. pylori gastritis and their clinical relevance. Sera from patients with dyspeptic symptoms were tested for presence of IgG immunoglobulins against H. pylori. Gastric infection with H. pylori and alterations of gastric mucosa were demonstrated by histological examination of gastric biopsy specimens. All sera were tested for reactivity against human gastric mucosa by immunohistochemistry. Two different in-situ binding sites of antigastric autoantibodies were observed. Binding to canalicular structures within parietal cells was significantly correlated with antibodies to H. pylori, elevated basal gastrin levels and atrophy of gastric corpus glands. Our data indicate that autoimmune reactions to antigens in the human gastric mucosa occur in H. pylori gastritis and that they may play a role in the pathogenesis of the disease.

Helicobacter pylori infection, serum gastrin, and gastric acid secretion in teen-age subjects with duodenal ulcer, gastritis, or normal mucosa

BACKGROUND

Many studies have confirmed the close association of Helicobacter pylori with duodenal ulcer (DU) in adults. However, in the subtype of DU known as 'childhood' or 'early onset DU' genetic factors seem to play a prominent role in the pathogenesis. The aim of this study was to investigate the prevalence of H. pylori in teen-age subjects with DU, gastritis, and normal mucosa and to examine the relationship of H. pylori to serum gastrin levels and gastric acid secretion.

METHODS

Sixty-one teen-age subjects (24 with DU, 14 with gastritis, and 23 normal subjects) were investigated for the presence of H. pylori, antral histology, gastrin levels, basal acid output (BAO), and maximal acid output (MAO).

RESULTS

All 24 patients with DU and 8 of 14 with gastritis were infected with H. pylori; none of the normal subjects were infected. Mean gastritis scores and fasting serum gastrin levels were significantly higher in patients with DU or H. pylori-positive gastritis than in subjects with H. pylori-negative gastritis or normal mucosa (p < 0.05). The difference in serum gastrin levels was also significant when patients with DU were compared with those with H. pylori-positive gastritis (p < 0.05). BAO and MAO were significantly higher in patients with DU than in subjects with H. pylori-positive gastritis or normal mucosa (p < 0.05), but there was no difference between subjects with H. pylori-positive gastritis and those with normal mucosa.

CONCLUSION

H. pylori infection is associated closely with teen-age DU and gastritis and with hypergastrinemia but does not affect BAO and MAO in most infected teen-age subjects.