Helicobacter pylori and gastric acid output in peptic ulcer disease

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.

Review article: Helicobacter pylori-negative duodenal ulcer disease

BACKGROUND

Helicobacter pylori infection rates in duodenal ulcer (DU) patients may be lower than previously estimated.

AIM

To review the real prevalence of H. pylori-negative DUs and its possible causes.

METHODS

Bibliographical searches in MEDLINE looking for the terms 'H. pylori' and 'duodenal ulcer'.

RESULTS

Mean prevalence of H. pylori infection in DU disease, calculated from studies published during the last 10 years including a total of 16 080 patients, was 81%, and this figure was lower (77%) when only the last 5 years were considered. Associations with H. pylori-negative DU were: (1) False negative results of diagnostic methods, (2) NSAID use (21% in studies with <90% infection rate), (3) Complicated DU (bleeding, obstruction, perforation), (4) Smoking, (5) Isolated H. pylori duodenal colonization, (6) Older age, (7) Gastric hypersecretion, (8) Diseases of the duodenal mucosa, (9) Helicobacter'heilmanii' infection and (10) Concomitant diseases.

CONCLUSION

In patients with H. pylori-negative DU disease, one should carefully confirm that the assessment of H. pylori status is reliable. In truly H. pylori-negative patients, the most common single cause of DU is, by far, the use of NSAIDs. Ulcers not associated with H. pylori, NSAIDs or other obvious causes should, for the present, be viewed as 'idiopathic'. True idiopathic DU disease only exceptionally exists.

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.

Reflux esophagitis patients in Singapore have motor and acid exposure abnormalities similar to patients in the Western hemisphere

OBJECTIVE

Endoscopic esophagitis is less common in the East than in the West. The reason for this is unknown. This study examines prospectively the relationship between endoscopic esophagitis and lower esophageal sphincter pressure, distal esophageal contractility, esophageal peristaltic performance, esophageal acid exposure, gastric acid output, and Helicobacter pylori (H. pylori) status in a consecutive series of Asian patients.

METHODS

Esophageal manometry and ambulatory pH monitoring were carried out in 48 patients with endoscopic esophagitis and 208 patients with symptoms suspicious of gastroesophageal reflux disease but without esophagitis. Gastric acid output and H. pylori serology were determined in 22 of the esophagitis group and 36 of the nonesophagitis group.

RESULTS

Compared to the nonesophagitis patients, esophagitis patients had a higher prevalence of hypotensive lower esophageal sphincter (49% vs 24%, p < 0.001), impaired esophageal contractility (45% vs 22%, p < 0.005), poor peristaltic performance (23% vs 12%, p < 0.05), and pathological acid reflux (48% vs 27%, p < 0.005). However, there was no difference in the two groups with respect to gastric acid output and H. pylori positivity.

CONCLUSIONS

Lower esophageal sphincter competence, esophageal peristaltic contractility, and esophageal acid exposure were important factors in the pathogenesis of reflux esophagitis--results identical to Western studies. Gastric acid output per se and H. pylori infection might not be responsible for susceptibility to esophagitis.

Reduced secretion of epidermal growth factor in duodenal ulcer patients with Helicobacter pylori infection

AIM: To investigate the concentration changes of epidermal growth factor (EGF) in duodenal ulcer patients with Helicobacter pylori (H. pylori) infection.

METHODS: Immunoreactive concentration of somatostatin, gastrin and epidermal growth factor of gastric and saliva juice in healthy volunteers, and chronic gastritis and duodenal ulcer patients with H. pylori infection were measured by radioimmunoassay.

RESULTS: Gastrin concentration of gastric juice in H. pylori-positive chronic gastritis (P > 0.05) and duodenal ulcer patients (P < 0.01) was higher than that of healthy volunteers (P < 0.05), whereas som atostatin concentration of gastric juice in chronic gastritis (P < 0.05) and duodenal ulcer patients (P < 0.01) was lower than that in healthy volunteers. Furthermore, EGF levels of gastric and saliva juice in duodenal ulcer patients with H. pylori infection (n = 10, 272.0 ng/L ± 96.3 ng/L and 8.3 ng/L ± 2.4 ng/L, respectively) were significantly lower than that in healthy volunteers (n = 12, 405.6 ng/L ± 35.6 ng/mL and 22.0 ng/L ± 17.0 ng/L, respectively) and in H. pylori-positive chronic gastritis patients (n = 25, 423.0 ng/L ± 104.0 ng/L and 22.0 ng/L ± 11.1 ng/L, respectively (P < 0.05).

CONCLUSION: A lower secretion of EGF may be a causative factor in the pathogenesis of H. pylori-positive duodenal ulcer.

Basal and stimulated gastrin levels and gastric acid output five months after therapy for Helicobacter pylori eradication in duodenal ulcer patients

The aim of our study was to demonstrate the effect of Helicobacter pylori eradication on basal and stimulated serum gastrin levels and gastric acid output 5 months after therapy of patients with duodenal ulcer. Thirty-two patients (24 men and eight women with a mean age of 45 years) who had had endoscopy and were diagnosed as having duodenal ulcer entered the study. In all patients three biopsy specimens were taken from the duodenal bulb, gastric antrum, body, and fundus. These specimens were then sent for microbiological and histological examination. Triple therapy consisting of bismuth, metronidazole, and tetracycline was administered. Endoscopy was repeated 1 and 5 months after therapy, and biopsy specimens were again taken from the gastric antrum and body. Before treatment, serum samples were taken to measure basal and stimulated (90 min) gastrin levels after ingestion of two beef cubes, and basal and stimulated acid outputs (after pentagastrin) were studied. Measurements of gastrin and gastric acid output were repeated 5 months after therapy. H. pylori was eradicated in 26 patients (81.3%). Basal gastrin levels (mean +/- SD) at diagnosis and after eradication were 44 +/- 12 and 35.8 +/- 2 pg/ml, respectively (p < 0.05). Similarly, stimulated gastrin levels (integrated values) decreased from 5,303 +/- 1,526 pg/ml/min before therapy to 3,779 +/- 1,204 pg/ml/min after eradication (p < 0.001). However, basal (4.9 +/- 4mEq/h) and stimulated (28.5 +/- 10mEq/h) acid output did not vary after eradication (3.9 +/- 4 mEq/h and 26.2 +/- 12 mEq/h, respectively). We conclude that basal and stimulated gastric acid output are not changed by H. pylori eradication in duodenal ulcer patients 5 months after therapy, in spite of its association with a significant decrease in basal and stimulated gastrin levels.

Duodenal ulcer, Helicobacter pylori, and gastric secretion

Patients with chronic dyspepsia were categorised by macroscopic appearance at oesophagogastroduodenoscopy as having duodenal ulceration (DU), other diagnosed lesions such as reflux oesophagitis, carcinoma of stomach, etc, or no organic lesion (non-ulcer dyspepsia, NUD). Material was collected to identify gastric infection with Helicobacter pylori (H pylori) by CP urease test, culture, and histological examination and to make the microscopic diagnosis of active chronic gastritis. Each patient in the DU and NUD categories was then invited to volunteer for a gastric secretion study in which maximal gastric secretion in response to histamine was measured. Sixty two gastric secretion tests were performed (31 DU, 31 NUD). The presence of H pylori was associated with active chronic gastritis (100%). DU patients secreted more acid than the NUD patients. H pylori positivity was associated with decreased maximal gastric secretion in both groups. There was a positive correlation between smoking and maximal acid output shown only in H pylori negative but not in H pylori positive patients. These findings were clear cut when all corrections of maximal gastric secretion were made for pyloric loss, duodenogastric reflux, and stature. This study failed to show any aetiological link between H pylori and DU by increased maximal gastric secretion.

Zollinger-Ellison syndrome and antral G-cell hyperfunction in patients with resistant duodenal ulcer disease

We measured basal and pentagastrin-stimulated acid secretion, as well as basal and meal-stimulated plasma gastrin concentration to determine, in 67 patients affected by resistant duodenal ulcer, whether their condition could be related to gastric acid secretion and/or gastrin-related syndromes. We then compared them to 46 duodenal ulcer control patients. The outpatients were investigated consecutively. The resistant duodenal ulcer patients differed from the controls only in their higher complication rates (bleeding or perforation, P < 0.05). We identified five patients in the resistant duodenal ulcer group with Zollinger-Ellison syndrome and 12 with antral G cell hyperfunction, whereas in the control group only one patient was affected by antral G cell hyperfunction. IgG anti-Helicobacter pylori antibodies were positive for the presence of infection in 7 of the hypergastrinaemic patients. When Zollinger-Ellison syndrome or antral G cell hyperfunction were excluded, no differences could be found in gastric acid secretion, or basal and meal-stimulated plasma gastrin levels, between the resistant and control duodenal ulcer patients, except for basal acid hypersecretion (resistant duodenal ulcer 16% vs duodenal ulcer 2% P = 0.0144). In the presence of duodenal ulcer disease resistant to H2-blockers, it is mandatory to measure basal plasma gastrin concentration since it was possible to diagnose the gastrin-related syndromes, Zollinger-Ellison syndrome and antral G cell hyperfunction, in 26% of this group of patients.

Circadian acidity pattern in prepyloric ulcers: a comparison with normal subjects and duodenal ulcer patients

We used continuous 24-h pH monitoring to compare the circadian intragastric acidity of 36 patients with prepyloric ulcers (PPU) with that of 101 normal subjects (NS) and that of 206 patients with duodenal ulcer (DU). The ulcer crater was endoscopically ascertained in all cases, and PPU were located within an area up to 2 cm proximal to the pylorus. The pH curve pertaining to DU patients ran below that of NS during most of the circadian period, whereas the pH profile of PPU patients was higher than that of NS, and this was particularly true during the evening and the night. The acidity of PPU patients was significantly lower (p < 0.01) than that of NS during the night only, whereas it was lower (p < 0.05-0.001) than that of DU patients during each time interval analysed (24 h, nighttime, and daytime). Our findings show that the gastric acidity of PPU patients differs greatly from that of DU patients, since it is lower throughout the whole 24-h period, and particularly during the night. Thus these two entities are pathophysiologically different with regard to the acidity pattern and should be considered two distinct subgroups of peptic ulcer disease instead of being incorporated, as usually happens, in the clinical group 'duodenal ulcer disease'.

Helicobacter pylori potentiates histamine release from serosal rat mast cells in vitro

Helicobacter pylori seems to be involved in the etiology of peptic ulcer and chronic gastritis. Histamine is fundamental in gastric secretion modulation, and some features of H. pylori-associated gastritis (edema, vasodilatation, inflammatory cell infiltration) are typical of the histamine-mediated response. This in vitro study has been undertaken as a preliminary step, in order to find a possible link between H. pylori and histamine release. H. pylori isolated from gastric biopsies has been tested as whole washed bacterium, whole formalin-killed bacterium, and crude cell wall preparation with serosal mast cells obtained by density gradient centrifugation or elutriation from peritoneal and pleural washings of male Wistar albino rats. Histamine release was assayed fluorimetrically. No significant histamine release was obtained by testing the various bacterial preparations alone with mast cells. On the contrary, whole washed cells, whole formalin-killed cells and crude cell walls from H. pylori have been found to potentiate compound 48/80 or calcium ionophore A23187-induced histamine release. Crude cell walls showed the highest activity, whereas filtered supernatants from broth cultures constantly appeared inactive. The enhancement in histamine release differed between the different strains. The present in vitro study, which shows the potentiating effect of H. pylori on histamine release, may prove interesting; however, at present, clinical implications cannot be inferred and further studies as well as in vivo demonstrations are needed.

The gastrointestinal tract in uremia

Gastrointestinal mucosal abnormalities ranging from edema to ulceration occur in two thirds of patients dying of uremia. Early studies suggested that uremic patients on maintenance dialysis treatment were at increased risk of peptic ulceration but more recent data indicate that this is not so. Other gastrointestinal problems reported for uremic subjects on maintenance dialysis treatment include bleeding from telangiectatic lesions, constipation, mucosal deposition of amyloid and acute pancreatitis. Nausea and vomiting are common in the uremic patient but gastric emptying studies have yielded conflicting results. Patients undergoing renal transplantation are at increased risk of development of esophagitis, complicated peptic ulcer, intestinal ulceration, and perforation as well as acute pancreatitis.

Helicobacter pylori in duodenal ulcer patients with idiopathic gastric acid hypersecretion

Thirty-three consecutive patients with idiopathic gastric acid hypersecretion (defined as a basal acid output > 10.0 meq/hr with a normal fasting serum gastrin level and negative secretin stimulation test) who were being treated for duodenal ulcer disease and other acid-peptic disorders were evaluated for the presence of Helicobacter pylori by means of a rapid urease test. Fourteen patients had duodenal ulcer and 19 had other acid-peptic disorders (gastroesophageal reflux in 14, including six with Barrett's esophagus; four with nonulcer dyspepsia; and one with erosive gastritis). Helicobacter pylori was present in 12 of the 14 ulcer patients (86%) compared to only two of the 19 nonulcer patients (11%) (P < 0.0001). The distribution of basal acid output for patients with duodenal ulcer was similar to that for nonulcer patients, and no significant difference in the mean basal acid output was found among Helicobacter pylori-positive compared to Helicobacter pylori-negative patients. Seven of the duodenal ulcer patients with a basal acid output greater than 15.0 meq/hr were Helicobacter pylori-positive, suggesting that the organism can withstand even extreme levels of gastric acidity. In conclusion, this study demonstrates that the prevalence of Helicobacter pylori infection in patients with duodenal ulcer disease associated with idiopathic gastric acid hypersecretion is not different from a majority of ulcer patients with normal acid secretory profiles and offers additional evidence that extreme levels of gastric acid are not bactericidal for the organism.

Non-immunological defence mechanisms of the gut

Non-immunological defence mechanisms represent an important line of intestinal defence in addition to humoral and cellular immunity. This review summarises the evidence for the role of the non-immunological defence system. Protective factors that have been amply documented are gastric juice, intestinal motility, and intestinal flora. Components of pancreatic juice, lysozyme, and epithelial cell turnover may also be involved. Special attention is given to gastric acid, infection with Helicobacter pylori, and hypochlorhydria and their association with infectious diarrhoea. Epidemic hypochlorhydria is discussed since this increases sensitivity to intestinal infections in third world countries.

Gastric Helicobacter and upper gastrointestinal symptoms in chronic renal failure

We studied histologically antral biopsies from 89 consecutive patients with chronic renal failure for Helicobacter pylori (previously Campylobacter pylori). A dose-response gastric secretion test was also performed. The frequency of Helicobacter-positive subjects was low (15/89, 17%), corresponding to figures reported in the literature for young symptomless volunteers. Helicobacter-positive patients had significantly more frequently upper gastrointestinal symptoms than Helicobacter-negative individuals (P less than 0.05). Antral gastritis was more common in the Helicobacter-positive than in the Helicobacter-negative renal patients (P less than 0.01), but the incidence of body gastritis did not differ between them. The Helicobacter-positive patients had lower serum urea levels (P less than 0.01) and higher acid outputs (P less than 0.001) than Helicobacter-negative subjects. All patients had raised fasting serum gastrin levels, which possibly obscured the difference between Helicobacter-positive (283 pg/ml) and -negative (331 pg/ml) patients. We conclude that in chronic renal failure gastric colonization of Helicobacter pylori is not more frequent than usual. It correlates positively with antral gastritis, gastric acid output and upper gastrointestinal symptoms, but negatively with serum urea levels.