Eradication of Helicobacter pylori in patients with duodenal ulcer lowers basal and peak acid outputs to gastrin releasing peptide and pentagastrin

The Physiology of the Gastric Parietal Cell

Parietal cells are responsible for gastric acid secretion, which aids in the digestion of food, absorption of minerals, and control of harmful bacteria. However, a fine balance of activators and inhibitors of parietal cell-mediated acid secretion is required to ensure proper digestion of food, while preventing damage to the gastric and duodenal mucosa. As a result, parietal cell secretion is highly regulated through numerous mechanisms including the vagus nerve, gastrin, histamine, ghrelin, somatostatin, glucagon-like peptide 1, and other agonists and antagonists. The tight regulation of parietal cells ensures the proper secretion of HCl. The H+-K+-ATPase enzyme expressed in parietal cells regulates the exchange of cytoplasmic H+ for extracellular K+. The H+ secreted into the gastric lumen by the H+-K+-ATPase combines with luminal Cl- to form gastric acid, HCl. Inhibition of the H+-K+-ATPase is the most efficacious method of preventing harmful gastric acid secretion. Proton pump inhibitors and potassium competitive acid blockers are widely used therapeutically to inhibit acid secretion. Stimulated delivery of the H+-K+-ATPase to the parietal cell apical surface requires the fusion of intracellular tubulovesicles with the overlying secretory canaliculus, a process that represents the most prominent example of apical membrane recycling. In addition to their unique ability to secrete gastric acid, parietal cells also play an important role in gastric mucosal homeostasis through the secretion of multiple growth factor molecules. The gastric parietal cell therefore plays multiple roles in gastric secretion and protection as well as coordination of physiological repair.

Helicobacter pylori and gastric acid: an intimate and reciprocal relationship

Helicobacter pylori (Hp) is the main cause of gastritis, peptic ulcer disease and gastric cancer. There are still unanswered questions related to the interaction between Hp and man, like what determines the susceptibility for the initial infection and the mechanisms for the carcinogenic effect. The initial infection seems to require a temporal gastric hypoacidity. For Hp to survive in the gastric mucous layer, some acidity is necessary. Hp itself is probably not directly carcinogenic. Only when inducing oxyntic mucosal inflammation and atrophy with hypoacidity, Hp predisposes for gastric cancer. Gastrin most likely plays a central role in the Hp pathogenesis of duodenal ulcer and gastric cancer.

NF-kappaB mediated transcriptional repression of acid modifying hormone gastrin

Helicobacter pylori is a major pathogen associated with the development of gastroduodenal diseases. It has been reported that H. pylori induced pro-inflammatory cytokine IL1B is one of the various modulators of acid secretion in the gut. Earlier we reported that IL1B-activated NFkB down-regulates gastrin, the major hormonal regulator of acid secretion. In this study, the probable pathway by which IL1B induces NFkB and affects gastrin expression has been elucidated. IL1B-treated AGS cells showed nine-fold activation of MyD88 followed by phosphorylation of TAK1 within 15 min of IL1B treatment. Furthermore, it was observed that activated TAK1 significantly up-regulates the NFkB subunits p50 and p65. Ectopic expression of NFkB p65 in AGS cells resulted in about nine-fold transcriptional repression of gastrin both in the presence and absence of IL1B. The S536A mutant of NFkB p65 is significantly less effective in repressing gastrin. These observations show that a functional NFkB p65 is important for IL1B-mediated repression of gastrin. ChIP assays revealed the presence of HDAC1 and NFkB p65 along with NCoR on the gastrin promoter. Thus, the study provides mechanistic insight into the IL1B-mediated gastrin repression via NFkB.

Review article: methods of measuring gastric acid secretion

BACKGROUND

Gastric acid has an important pathophysiological role in human beings. Numerous methods have been evaluated over the years in an attempt to measure gastric acid and stomach acidity, to study the role of gastric acid in gastrointestinal diseases in humans and to evaluate the effects of acid suppressing drugs.

AIM

To review methods that have been used to measure gastric acid and gastric acidity.

METHODS

Searches of the electronic databases PUBMED, MEDLINE and EMBASE, were performed with articles restricted to English language and human subjects. References were also identified from the bibliographies of selected articles.

RESULTS

Methods for measuring gastric acid include both invasive and non-invasive techniques. Invasive tests include the conventional gastric acid aspiration tests, gastric pH measurement techniques and endoscopic methods. Non-invasive methods use urinary analysis, breath analysis, serum pepsinogens assay, scintigraphic techniques, impedence tomography and alkaline tide for measurement of gastric acid.

CONCLUSIONS

Several methods of measuring gastric acid exist. Invasive tube tests are uncomfortable and time consuming, whereas most of the non-invasive methods are at best semiquantitative and useful in detecting low or absent acid secretion. Further attempts to explore new methods for measuring gastric acid are therefore warranted.

IL1B induced Smad 7 negatively regulates gastrin expression

Background

Helicobacter pylori elicited IL1B is one of the various modulators responsible for perturbation of acid secretion in gut. We have earlier reported that IL1B activated NFkB downregulates gastrin, a major modulator of acid secretion. However, we hypothesized that regulation of gastrin by IL1B would depend on the cell's ability to integrate inputs from multiple signaling pathways to generate appropriate biological response.

Principal Finding

In this study, we report that IL1B induces Smad 7 expression by about 4.5 fold in gastric carcinoma cell line, AGS. Smad 7 resulted in transcriptional repression of gastrin promoter by about 6.5 fold when co -transfected with Smad 7 expression vector and gastrin-promoter luciferase in AGS cells. IL1B inhibited phosphorylation of Smad 3 and subsequently interfered with nuclear translocation of the positive Smad complex, thus occluding it off the gastrin promoter. IL1B promoter polymorphisms (-511T/-31C IL1B) are known to be associated with H. pylori associated gastro-duodenal ulcer. We observed that IL1B expressed from -31T promoter driven IL1B cDNA elicited 3.5 fold more Smad 7 than that expressed from the IL1B-31C variant in AGS cells. This differential activation of Smad 7 by IL1B promoter variants translated into differential downregulation of gastrin expression. We further analyzed Smad 7, NFkB, IL1B and gastrin expression in antral gut biopsy samples of patients with H. pylori associated duodenal ulcer and normal individuals. We observed that individuals with duodenal ulcer had significantly lower levels of IL1B, Smad 7, NFkB and corresponding higher level of gastrin expression.

Conclusion

Pro-inflammatory cytokine IL1B repress gastrin expression by activating Smad 7 and subsequent inhibition of nuclear localization of Smad 3/4 complex. Polymorphic promoter variants of IL1B gene can modulate the IL1B expression which resulted in differential activation Smad 7 and consequent repression of gastrin expression, respectively. Analysis of H. pylori infected duodenal ulcer patient's gut biopsy samples also supported this observation.

Effect of Helicobacter pylori infection and its eradication on reflux esophagitis and reflux symptoms

OBJECTIVES

We evaluated the association between current Helicobacter pylori infection and reflux esophagitis and the effect of H. pylori eradication on reflux esophagitis in a healthy screening population.

METHODS

A total of 10,102 subjects in a comprehensive screening cohort were enrolled, and 4,007 subjects had follow-up after a median of 2 years. Effects of H. pylori infection on reflux esophagitis were estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using multiple logistic regression analysis. We evaluated the change in prevalence of reflux esophagitis and reflux symptoms after H. pylori eradication vs. persistence.

RESULTS

The prevalence of reflux esophagitis (as classified by the Los Angeles system) was 4.9% (490/10,102). Whereas the prevalence of reflux esophagitis was 6.4% (319/4,971) in subjects without H. pylori infection, it was 3.3% (171/5,131) in subjects with infection (P<0.001). H. pylori infection had a strong negative association with reflux esophagitis in multivariate analysis (OR 0.42; 95% CI, 0.34-0.51). Compared with the prevalence of reflux esophagitis in the persistent infection group, the prevalence of reflux esophagitis increased after successful H. pylori eradication (OR 2.34; 95% CI, 1.45-3.76; P<0.001), which was comparable to that of the H. pylori-negative group (OR 2.42; 95% CI, 1.73-3.36; P<0.001). However, reflux symptoms had no association with H. pylori infection or eradication.

CONCLUSIONS

In a healthy screening population, H. pylori infection had a strong negative association with reflux esophagitis, but H. pylori eradication increased the prevalence of erosive esophagitis to the level of H. pylori-negative individuals. Long-term clinical significance of newly developed erosive esophagitis after H. pylori eradication should be evaluated prospectively.

Effect of interleukin-8 on histamine release from totally isolated vascularly perfused rat stomach

BACKGROUND

Recent studies have demonstrated relationships between cytokines and gastric acid secretion. The present study was performed in rats to elucidate the effects of interleukin-8 (IL-8) on gastric acid secretion through an increase in histamine release from the stomach.

METHODS

The experiments were performed in gastric lumen-perfused rats for the study of acid secretion and in totally isolated vascularly perfused rat stomach preparations for the study of histamine release. The histamine in the effluent was determined by radioimmunoassay.

RESULTS

IL-8 (500 ng) significantly enhanced gastrin-stimulated acid secretion. IL-8, at a concentration of 500 ng/20 ml per 10 min, did not alter basal histamine release, but at 100 ng/20 ml and 500 ng/20 ml it dose-dependently increased gastrin-stimulated histamine release.

CONCLUSIONS

IL-8 enhances gastrin-stimulated acid secretion and histamine release from the rat stomach, which may explain the enhancing effect of IL-8 on gastric acid secretion.

The diurnal profile of gastric pepsin activity is reduced with Helicobacter pylori infection

Both Helicobacter pylori and pepsin are proven mucosal damaging agents and implicated in the aetiology of peptic ulcer disease. Historically studies of pepsin over time have proved methodologically difficult, and as a result little work has been done on the effect of H. pylori on luminal pepsin secretion. Our objectives were to determine pepsin activity over 24 hr in normal human subjects and to examine luminal pepsin activity in relation to H. pylori infection. Twenty-seven healthy volunteers had gastric juice samples aspirated every 2 hr for 24 hr. All subjects had H. pylori status determined by C13 urea breath test and serology. Meals were standardized throughout the study period. Gastric juice samples were measured for pH, diluted, and frozen in acetate buffer pH 4.1 for up to 1 month, conditions shown to cause no loss of activity. Individual samples were measured for pepsin activity by assaying for new N-terminal peptide formation. Mean pepsin activity (microg enzyme/ml) in 21 normal H. pylori-negative subjects ranged from 114 to 1030 microg/ml, with a characteristic diurnal profile of increasing activity to maximum after the evening meal. Mean pepsin activity in subjects with H. pylori was consistently below that for age-matched H. pylori-negative subjects at each time point. Overall mean pepsin activity was significantly lower in those with H. pylori compared to those without (P < 0.001). There is significant pepsin activity in the stomach throughout the 24-hr period, with a trend for the highest activity through the night. Subjects with H. pylori infection have lower luminal pepsin activity.

Effect of Helicobacter pylori infection on gastric acid secretion and meal-stimulated serum gastrin in children

BACKGROUND

Comparative studies of gastric acid secretion in children related to Helicobacter pylori infection are lacking. The purpose of this study was to compare acid secretion and meal-stimulated gastrin in relation to H. pylori infection among pediatric patients.

MATERIALS AND METHODS

Thirty-six children aged 10-17 years (17 with H. pylori infection) undergoing diagnostic endoscopy participated in the study. Diagnoses included gastritis only (n = 23), duodenal ulcer (n = 5) and normal histology (n = 8). Gastric acid output was studied using the endoscopic gastric secretion test before and 2-3 months after H. pylori eradication. Meal-stimulated serum gastrin response was assessed before and 12 months after eradication.

RESULTS

H. pylori gastritis was typically antrum-predominant. Acid secretion was greater in H. pylori-positive patients with duodenal ulcer than in gastritis-only patients or controls [mean +/- standard error (SE): 6.56 +/- 1.4, 3.11 +/- 0.4 and 2.65 +/- 0.2 mEq/10 minutes, respectively; p <.001]. Stimulated acid secretion was higher in H. pylori-positive boys than girls (5.0 +/- 0.8 vs. 2.51 +/- 0.4 mEq/10 minutes, respectively; p <.05). Stimulated acid secretion pre- and post-H. pylori eradication was similar (5.47 +/- 0.8 vs. 4.67 +/- 0.9 mEq/10 minutes, respectively; p =.21). Increased basal and meal-stimulated gastrin release reversed following H. pylori eradication (e.g. basal from 134 to 46 pg/ml, p <.001 and peak from 544 to 133 pg/ml, p <.05).

CONCLUSIONS

H. pylori infection in children is associated with a marked but reversible increase in meal-stimulated serum gastrin release. Gastric acid hypersecretion in duodenal ulcer remains after H. pylori eradication, suggesting that the host factor plays a critical role in outcome of the infection.

Personal view: to treat or not to treat? Helicobacter pylori and gastro-oesophageal reflux disease - an alternative hypothesis

Helicobacter pylori causes acute on chronic gastritis and is responsible for most peptic ulcers and gastric cancer. However, recent papers have suggested that it may protect against gastro-oesophageal reflux, Barrett's oesophagus and oesophageal cancer. Furthermore, the rapid increase in gastro-oesophageal reflux disease, Barrett's oesophagus and adenocarcinoma of the oesophagus in the developed world has been attributed by some to the falling prevalence of H. pylori. These considerations have led to the suggestion that H. pylori infection should not necessarily be treated, especially in patients with gastro-oesophageal reflux disease. Conversely, data from prospective randomized studies have shown that H. pylori eradication does not cause gastro-oesophageal reflux disease in patients with duodenal ulcer or in the normal population, nor does it worsen the outcome of pre-existing gastro-oesophageal reflux disease. Therefore, although H. pylori is negatively associated with gastro-oesophageal reflux disease, its eradication does not induce the disease. A hypothesis is presented suggesting that the increased prevalence of gastro-oesophageal reflux disease is a result of rising acid secretion in the general population, which, in turn, is a consequence of the increased linear height (a predictor of acid secretion). The greater acid secretion could also explain the decline in the prevalence of H. pylori and perhaps account for the inverse relationship between H. pylori and gastro-oesophageal reflux disease. These considerations are explored in discussing whether H. pylori infection should be treated in infected patients presenting with gastro-oesophageal reflux disease.

Inhibitory potency of twice-a-day omeprazole on gastric acidity is enhanced by eradication of H. pylori in duodenal ulcer patients

The gastric pH-elevating effect of proton pump inhibitors such as omeprazole has been reported to be greater in the presence than in the absence of an H. pylori infection. It is unknown if this effect persists when a higher dose of omeprazole is taken. We undertook both 24-hr pH-metry and 24-hr aspiration studies in 12 H. pylori-positive patients with a history of duodenal ulcer (DU); (1) when not on omeprazole; (2) when on omeprazole 20 mg twice a day for 8 days; (3) two months after eradication of H. pylori and when not on omeprazole; and (4) after eradication of H. pylori and when on omeprazole twice a day. Eradication of H. pylori in DU results in lower mean and median pH; decreased percent pH > or = 3/ > or = 4, and greater median H+ after breakfast, after lunch, and overnight; and omeprazole appears to have less of a pH-elevating effect in the absence than in the presence of an H. pylori infection. The fall in gastric juice NH3 concentration as a result of eradicating H. pylori partially explained the lower pH-elevating effect of omeprazole. The variation in acid inhibitory effect of omeprazole after as compared with before eradication of H. pylori could not be explained by differences; (1) in gastric juice concentrations of IL-1alpha, IL-8, IL-13, or epidermal growth factor; (2) in the fasting or fed total concentration of gastric juice bile acids; (3) in the fasting concentrations or area under-the-curve (AUC) of the gastric H+ concentrations in response to food; or (4) in the pharmacokinetics of omeprazole. The difference in H+ AUC without omeprazole minus with omeprazole was actually greater when compared after versus before eradication of H. pylori. Thus, in DU the pH-elevating potency of omeprazole taken twice a day is greater in the presence than in the absence of an H. pylori infection.

Active and inactive gastroesophageal reflux diseases related to Helicobacter pylori therapy

We systematically reviewed the literature on gastroesophageal reflux disease (GERD) related to Helicobacter pylori therapy, and classified the GERD according to various aspects. Preexisting GERD is active GERD before H. pylori therapy, and a substantial proportion of the GERD patients improve after successful H. pylori therapy. If the GERD does not persist or recur after cessation of acid-suppressive therapy combined with H. pylori therapy, it may have been cured (cured GERD). If it recurs, it may have been masked by acid-suppressive therapy and unmasked with cessation of the therapy (pharmacologically masked and unmasked GERD). Newly developed GERD after successful H. pylori therapy is a kind of unmasked GERD arising after cure of infection (de novo unmasked GERD). The possible mechanism of the improvement of cured GERD is normalized hyperacidity associated with an improved cytokine-somatostatin-gastrin system followed by normalized G-cell activity and parietal cell mass. Preexisting GERD is not a reason to avoid eradication therapy. De novo unmasked GERD develops in a substantial proportion of patients with cured infection. The possible mechanism is increased acid exposure in the esophagus due to gastric acid increase, which is caused by a loss of neutralizing effect by ammonia, normalized cytokine-acid suppression and improvement of corpus atrophy. De novo unmasked GERD is important because GERD is recurrent and may induce adenocarcinoma of the esophagus. However, it is expected that cure of infection lowers gastric cancer incidence. Eradication therapy is recommended irrespective of the possibility that de novo unmasked GERD may have a slight increase of the risk of esophageal adenocarcinoma.

Neutrophil-derived hydroxyl radicals mediate interleukin-8-induced increases in tetragastrin-stimulated acid secretion in rats

Until recently, the secretion of gastric acid, which plays an important role in the pathogenesis of peptic ulcer, was thought to be controlled by diet, the autonomic nerves and gut hormones. However, peptic ulcer is now known to be caused by the infection with Helicobacter pylori (H. pylori), so it is possible that inflammation modifies the secretion of gastric acid. We used gastric-lumen-perfused rats to first examine the effect of interleukin-8 (IL-8) on acid secretion and then the involvement of free radicals and neutrophils in the action of IL-8. IL-8 enhanced tetragastrin-stimulated acid secretion and free radical scavengers or inhibitors and the pretreatment with anti-rat neutrophil serum inhibited this effect, which indicates that IL-8 enhances gastrin-stimulated acid secretion and that neutrophil-derived hydroxyl radicals mediate the IL-8-induced increase in acid secretion.

Effect of Helicobacter pylori eradication on development of erosive esophagitis and gastroesophageal reflux disease symptoms: a post hoc analysis of eight double blind prospective studies

OBJECTIVES

The aim of this study was to assess the development of erosive esophagitis, the development of gastroesophageal reflux disease (GERD) symptoms in patients without prior symptomatic or endoscopic GERD, and the worsening of GERD symptoms in patients with prior symptomatic GERD in a post hoc analysis of eight double-blind prospective trials of Helicobacter pylori (H. pylori) therapy in 1165 patients.

METHODS

Patients with active or past duodenal ulcer and without baseline erosive esophagitis had end of study endoscopies 4-30 wk after completion of therapy. A total of 533 patients had heartburn and regurgitation scores assessed at baseline and 4 wk after end of therapy, and were divided into two groups: 1) no prior GERD symptoms (N = 127) and 2) prior GERD symptoms (N = 406). H. pylori was assessed at baseline and > or = 4 wk after therapy by rapid urease test, histology, and culture.

RESULTS

Erosive esophagitis developed in 24 (4%) of 621 patients with cure versus 14 (3%) of 544 with persistent H. pylori (OR = 1.52, 95% CI = 0.78-2.97). In the longest study (28-30-wk follow-up), esophagitis developed in two (7%) of 28 patients with cure versus five (7%) of 76 with persistent infection. New GERD symptoms developed in 13 (14%) of 92 patients with cure versus seven (20%) of 35 with persistent infection (OR = 0.66,95% CI = 0.24-1.82). GERD worsened in 20 (7%) of 269 with cure vs 20 (15%) of 137 with persistent H. pylori (OR = 0.47, 95% CI = 0.24-0.91; p = 0.02).

CONCLUSIONS

Our results do not support the hypothesis that H. pylori eradication in patients with duodenal ulcer disease leads to the development of erosive esophagitis, the development of new symptomatic GERD, or worsening of symptoms in patients with pre-existing GERD.

Pediatric disorders of the stomach

Disorders of the stomach represent a significant portion of the practice of pediatric gastroenterology. Controversy still exists in the appropriate management of children with abdominal pain and vomiting and large gaps remain in our understanding of the physiology and pathophysiology of the stomach in children. Nevertheless, we have made significant progress in understanding Helicobacter pylori infection and gastric motility in the pediatric population.

Helicobacter pylori eradication does not worsen quality of life related to reflux symptoms: a prospective trial

BACKGROUND

Concern has been raised that Helicobacter pylori therapy may lead to the development of gastro-oesophageal reflux disease. This prospective study was designed to assess reflux-related quality of life and the symptoms of gastro-oesophageal reflux disease in patients undergoing H. pylori therapy.

METHODS

Patients with a primary complaint of dyspepsia (upper abdominal pain or discomfort) and endoscopic biopsy positive for H. pylori received triple therapy for 2 weeks. A validated reflux-related quality of life questionnaire sensitive to change was given at baseline, 1 month and 6 months after therapy; symptoms were also recorded. A urea breath test was performed 1 month after the end of therapy; patients and investigators were blind to the results.

RESULTS

H. pylori was eradicated in 48 of 61 patients. The mean scores in cured patients for each of the five domains were comparable at baseline and 6 months after therapy: differences were - 0.23 to 0.13 (P > 0.20) on a scale of 1-7. The proportion of cured patients with a large decrease in quality of life (10-17% in the five domains) was similar to the proportion with a large increase (15-21%). Heartburn was present at baseline in 22 cured patients; at 6 months, it persisted in 13 and resolved in nine, whilst nine patients developed new heartburn.

CONCLUSIONS

A population of patients presenting with dyspepsia should have no overall increase or decrease in quality of life due to symptomatic gastro-oesophageal reflux disease in the 6 months after H. pylori therapy.

Influence of Helicobacter pylori infection on the prevalence of reflux esophagitis in Japanese patients

BACKGROUND AND AIM

Reflux esophagitis is caused by esophageal motor dysfunction in patients with sufficient gastric acid secretion. Helicobacter pylori causes atrophic gastritis and influences gastric acid secretion. Hiatus hernia (HH) of the esophagus causes motor dysfunction in the lower esophagus. Therefore, this study aimed to test whether H. pylori infection, gastric mucosal atrophy and HH are predictive factors for reflux esophagitis.

METHODS

Helicobacter pylori infection was examined in 781 patients by the measurement of serum immunoglobulin (Ig)G antibody, bacteriological culture and histological examination of biopsy specimens. The prevalence of HH, endoscopically identified gastric mucosal atrophy (closed- or open-type) and reflux esophagitis were investigated by reviewing endoscopic films. Investigated patients were divided into three age groups, under 49, 50-69, and over 70 years. The prevalence of esophagitis, H. pylori infection, gastric mucosal atrophy, and HH were compared to identify the possible predictive factors for reflux esophagitis by using logistic regression analysis.

RESULTS

Sixty-nine patients with reflux esophagitis were found among the 781 investigated cases. The odds ratios of negative H. pylori infection, endoscopically identified closed-type gastric mucosal atrophy, and HH for the prevalence of reflux esophagitis were 1.342, 1.751 and 5.527, respectively. These results indicated that the presence of H. pylori infection was only a weak negative risk factor, and that HH was the most reliable endoscopic predictive factor for reflux esophagitis.

CONCLUSION

Helicobacter pylori infection is a weak negative risk factor for the prevalence of reflux esophagitis, while HH is the most reliable predictive factor.

Effectiveness of acid suppression in preventing gastroesophageal reflux disease (GERD) after successful treatment of Helicobacter pylori infection

There is evidence that Helicobacter pylori eradication might predispose to gastroesophageal reflux disease (GERD). The aim of this prospective study was to examine the effectiveness of antisecretory treatment, after successful H. pylori eradication, in preventing GERD, since no data exist so far. Eighty initially H. pylori(+) patients, without GERD at the time of H. pylori eradication [50 peptic ulcer (PU) and 30 nonulcer (NU), 55 men, 25 women, median age 38 years, range 19-57], after successful H. pylori eradication were randomized to recieve either omeprazole 20 mg daily (group A) or no treatment (group B) for one year. All patients underwent upper gastrointestinal endoscopy at 0, 6, and 12 months or when GERD symptoms occurred. There were 40 patients in each group, and there were no statistically significant differences between the two groups in terms of sex, age, body weight, ulcer/no ulcer ratio, and other demographic data. Seven patients from group A and five patients from group B were lost to follow-up, and therefore there were 33 and 35 patients in groups A and B, respectively, who completed the study. One of 33 patients in group A (3%) and 10/35 (28.5%) in group B developed GERD symptoms during follow-up (P = 0.0022). The respective values for esophagitis were 0/33 (0%) and 6/35 (17.1%) (P = 0.0083). In conclusion, antisecretory treatment in H. pylori(+) patients, after successful eradication, is effective in preventing GERD.

The association between CagA status and the development of esophagitis after the eradication of Helicobacter pylori

BACKGROUND

Strains of Helicobacter pylori with the cytotoxine-associated gene A (cagA) are linked to severe forms of gastroduodenal disease. Although eradication of H. pylori may predispose to the development of reflux esophagitis, the effects of CagA status on risk of esophagitis after successful H. pylori treatment are not known.

METHODS

We studied 50 consecutive patients without esophagitis in whom H. pylori was eradicated successfully. CagA status was determined by immunoblotting sera from patients against H. pylori antigens. Patients underwent upper gastrointestinal endoscopy before eradication and 6, 12, 18, and 24 months after eradication or when reflux symptoms occurred. Biopsy specimens of the antrum and corpus were evaluated for gastritis before H. pylori eradication and at the end of the study. The sum of the scores for acute and chronic inflammation (both measured on a 0 [absent] to 3 [severe] scale) comprised the total gastritis severity score.

RESULTS

In a multivariate proportional hazards regression analysis, positive CagA serology (hazard ratio [HR] = 10, 95% confidence interval [CI]: 1.3 to 81) and moderate-to-severe corpus gastritis (total severity score > or =4) before eradication (HR = 2.3, 95% CI: 1.2 to 6.1) were independent risk factors for the development of esophagitis after H. pylori eradication.

CONCLUSION

Patients infected with strains of H. pylori that are cagA-positive are at increased risk of developing esophagitis after eradication of H. pylori.

Protective effect of ammonia against reflux esophagitis in rats

Although several recent studies have reported that curing Helicobacter pylori (H. pylori) may result in the development of reflux esophagitis (RE), the mechanisms leading to this complication are unknown. One by product of H. pylori infection is ammonia, which serves as an acid neutralizer. The aim of this study was to clarify whether ammonia, which is produced during H. pylori infection, has a protective effect on the esophagus. Eight-week-old male Sprague-Dawley rats were fasted for 24 hrs. Under anesthesia, both the pylorus and limiting ridge were simultaneously ligated. One hour postligation, 0.3 ml of saline or ammonia at various concentrations was administered intragastrically by gastric intubation. Three hours after ligation, the animals were killed, the esophagus and stomach were removed, and the length of esophageal hemorrhagic erosions was measured. The incidence of RE was 100% (7/7) in the control group, 71% (5/7) in the low-ammonia group, 29% (2/7) in the middle-ammonia group, and 14% (1/7) in the high-ammonia group. The severity of lesions decreased in correspondence to increases in ammonia concentration. The development of RE was significantly inhibited by ammonia in a dose-dependent manner. This study indicates that ammonia protects against development of RE. A decreased amount of ammonia in the stomach might be related to the development of RE after H. pylori eradication therapy.

Peptic ulcer and Helicobacter pylori

Although there has been an explosion of data not only since the discovery of H. pylori in 1982, but also since the first comprehensive review of H. pylori in the Gastroenterology Clinics in 1993, much remains to be learned. In 1993, there were many skeptics doubting the importance of H. pylori in ulcer disease. Although this skepticism has dissipated, many ulcer patients infected with H. pylori still do not receive appropriate therapy. This situation possibly relates to the safety, efficacy, and simplicity of prescribing acid-suppressive therapy in contrast to the confusion regarding anti-H. pylori treatment regimens. Among the many continuing unanswered questions regarding the role of H. pylori and PUD are the still enigmatic nature of host, environmental, and H. pylori-related factors that determine outcome. Why do only some infected individuals (and why do more men than women) develop PUD, and what determines whether gastric ulcers or duodenal ulcers develop? What is the explanation for the seasonal variation in ulcer disease? Although PUD is an infectious disease, are other environmental factors critical for the manifestation of ulcers in association with infection? What factors govern the outcome of the combination of H. pylori infection and NSAID use? Has attention been too focused first on the pathophysiology of acid secretion and now on H. pylori? In curing H. pylori in association with PUD, are clinicians going to displace disease northward, substituting erosions, inflammation, and neoplasia (and associated symptoms) in the esophagus and gastroesophageal junction for an ulcer crater (and its associated symptoms) in the duodenum or stomach? The epidemiology of PUD is changing--in more recent reports of ulcer patients, H. pylori and NSAID use are less prevalent than in earlier reports. These questions and comments should not be misinterpreted as advocating a lack of aggressiveness in diagnosis and treatment of H. pylori in the setting of PUD, however. Nevertheless, the pendulum is swinging.

Role of cyclooxygenase-2 in modulating gastric acid secretion in the normal and inflamed rat stomach

Nonsteroidal anti-inflammatory drugs elevate gastric acid secretion, possibly contributing to their ability to interfere with gastric ulcer healing. Inhibitors of cyclooxygenase-2 have been shown to delay experimental gastric ulcer healing. In the present study, we tested the hypothesis that cyclooxygenase-2-derived prostaglandins modulate gastric acid secretion. Studies were performed in normal rats and in rats with iodoacetamide-induced gastritis. Inflammation in the latter group was confirmed histologically and by a threefold increase in tissue levels of the granulocyte marker myeloperoxidase and was also associated with overexpression of cyclooxygenase-2 in the stomach. Basal acid secretion in both groups of rats was not affected by pretreatment with DuP-697, a selective inhibitor of cyclooxygenase-2. A nonselective cyclooxygenase inhibitor, indomethacin, had no effect on acid secretion in normal rats but caused a doubling of acid secretion in the rats with gastritis. DuP-697 had no effect on pentagastrin-induced secretion in either group of rats. Gastritis itself was associated with significantly increased pentagastrin-induced acid secretion, and this was further increased in rats pretreated with indomethacin. These results suggest that in a setting of gastric inflammation, prostaglandins derived from cyclooxygenase-1, not cyclooxygenase-2, exert inhibitory effects on acid secretion.

Relationship between antral lymphocyte density and basal gastrin levels in patients with Helicobacter pylori infection

BACKGROUND

The mechanism by which Helicobacter pylori causes hypergastrinaemia is not completely understood.

AIM

To evaluate whether antral lymphocyte density could play a role in this alteration.

METHODS

A total of 12 patients with active duodenal ulcer and 10 with non-ulcer dyspepsia were enrolled upon detection of Helicobacter pylori infection at endoscopy Enrolled as controls were 7 matched dyspeptic patients without Helicobacter pylori infection. Biopsy specimens were collected for Helicobacter pylori and histological assessments, and for antral lymphocyte density assessment by a histomorphometric method. A blood sample was obtained from each patient to determine basal gastrin levels. All patients were controlled by a further endoscopy 4 weeks after the end of Helicobacter pylori treatment.

RESULTS

Antral lymphocyte density (5,464 +/- 1,328 and 5,635 +/- 1,186 vs 2,267 +/- 557 lymphocytes/mm2; p<0.001 and p<0.001, respectively) and gastrin levels (66.7 +/- 14.1 and 60.4 +/- 21.7 vs 40.7 +/- 7.8 pg/dl; p=0.004 and p=0.02, respectively) were higher in duodenal ulcer and non-ulcer dyspepsia patients than in controls, while no significant differences emerged between duodenal ulcer and non-ulcer dyspepsia patients. There was a significant direct correlation between antral lymphocyte density and gastrin levels both in duodenal ulcer (r=0.77; p=0.003) and in non-ulcer dyspepsia (r=0.75; p=0.03) patients, while no correlation was found in controls [r=0.12; p=0.8). After treatment, this correlation persisted in 10 eradication failure patients (r=0.68; p=0.027), but disappeared in those successfully cured.

CONCLUSIONS

These data suggest that lymphocyte density in the antral mucosa could play a role in the impaired gastrin production occurring in patients with Helicobacter pylori infection.

Autonomic control of heart period in duodenal ulcer patients insights from spectral analysis of heart rate variability

Beyond the fundamental pathogenetic importance of Helicobacter Pylori a possible additional role of vagal innervation in favouring or modulating the clinical history of duodenal ulcer (DU) has been suggested by old studies employing invasive methodologies. Aim of this study was to assess whether vagal prevalence in autonomic modulation was present in healed DU patients (n=20) as compared to controls,(n=50), using a validated non-invasive methodology, based on spectral analysis of cardiovascular variability. This approach provides markers of the sympathetic and vagal modulations of the SA node, respectively by way of the normalized low frequency (LF(RR)) and high frequency (HF(RR)) components of RR interval variability; LF/HF ratio furnishes a marker of sympatho-vagal balance. In addition, sham feeding (SF) provided a means to assess, in DU patients, neurally mediated acid secretion, as the SF acid output (SAO) to basal acid output (BAO) ratio (SAO/BAO). Results showed that LF(RR) was smaller in DU patients than in controls (40.3+/-3.9 vs. 52.3+/-2.3 normalized units, nu; P<0.05). On the contrary, HF(RR) was greater (52.1+/-3.7 vs. 35.7+/-2.3 nu; P<0.05). Conversely the LF component of SAP variability, a marker of sympathetic vasomotor modulations, and the index alpha, a measure of baroreflex control of the SA node, as well as respiratory patterns, were similar in the two groups. SAO/BAO ratio was significantly correlated with markers of autonomic control of the SA node (r = -0.67, P<0.0083 with HF(RR)). In conclusion results suggest an enhanced vagal modulation of heart period in DU patients at rest, that appears linked to indices of neurally mediated gastric acid secretion response.

Review article: is Helicobacter pylori status relevant in the management of GORD?

There is growing interest in the relationship between H. pylori infection and gastro-oesophageal reflux disease (GORD). However, this relationship is complex, as yet not fully elucidated, and probably based on a multiplicity of factors. The prevalence of H. pylori infection in patients with GORD is similar, more often lower than in matched controls. There is a negative correlation between H. pylori infection and the severity of GORD. There are many hypothetical mechanisms by which H. pylori infection may protect from the development of GORD. Conversely, there are many possible mechanisms by which H. pylori infection could theoretically foster the GORD. Patients after H. pylori eradication may develop GORD, and this seems to suggest a protective role of H. pylori infection, but other possible explanations include weight gain after H. pylori eradication, changes in dietary habits and smoking, and pre-existing GORD. H. pylori infected patients treated by various acid-inhibiting therapies such as proton pump inhibitors (PPIs), H2-receptors antagonists (H2-RA) or vagotomy, have an increase of their corpus gastritis severity, both in the activity of inflammation and in the density of organisms. Long-term therapy of GORD in H. pylori infected may lead to rapid progression of atrophic gastritis intestinal metaplasia and dysplasia, and increase the risk of developing gastric cancer. More recently it has been shown that H. pylori infection may interfere with the acid suppressive therapies used for treating GORD. In our opinion the progression of gastritis depends on the threshold of acid output at which H. pylori can 'flourish'. Recently interest is growing on gastric transitional zones and Helicobacter ecology. Any decrease of acid secretion changes the behaviour of H. pylori: the activity of gastritis improves in the antrum, but it deteriorates in the body. During proton pump inhibitor treatment, H. pylori redistribution occurs within the stomach, from an antral to a corpus or fundus prevalent pattern; corpus-fundus gastritis, exacerbated by PPI therapy, may result both in a diminished acid secretion and gastro-oesophageal reflux. The interest in Barrett's oesophagus is growing due to the associated risk of adenocarcinoma. The literature seems to demonstrate that the prevalence of H. pylori infection of the stomach in Barrett's oesophagus patients is not different from that exhibited by controls, roughly one-third of the subjects. Intestinal metaplasia of the gastric cardia seems to be equally frequent in patients with and without GORD. Finally, it appears unlikely that a causal relationship exists between H. pylori infection and Barrett's-associated adenocarcinoma.

Helicobacter pylori gastritis and gastric physiology

It is now recognized that Helicobacter pylori infection exerts profound and diverse effects on gastric acid secretory function and that the alterations in acid secretion depend on the pattern of gastritis caused by the infection. In patients with an antral predominant nonatrophic gastritis, there is acid hypersecretion leading to duodenal ulcer disease. In patients with an atrophic pangastritis, there is markedly reduced acid secretion and increased risk for gastric cancer. It is now recognized that acid secretion also modifies H. pylori gastritis and a person's premorbid acid secretory status may be an important factor in determining the pattern of gastritis that an individual develops. This two-way interaction between H. pylori gastritis and gastric acid secretion is important in understanding the role of H. pylori infection in the response to proton-pump inhibitor therapy: It explains the more profound control of gastric acid secretion in H. pylori-positive patients and why rebound acid hypersecretion is confined to H. pylori-negative subjects.

Effect of Helicobacter pylori eradication on 24-hour gastric pH and duodenal gastric metaplasia

Published data on the regression of the extent of duodenal gastric metaplasia (DGM) after the eradication of Helicobacter pylori infection and the normalization of the organism-induced alterations in gastric physiology are scanty and controversial. Therefore, we decided to assess the circadian pattern of gastric acidity and the degree of DGM before and one year after H. pylori eradication in a group of duodenal ulcer patients. Fifteen consecutive H. pylori-positive patients with endoscopically proven duodenal ulcer were recruited for this study. The diagnosis of H. pylori infection was based on CLO-test and histology, and DGM was assessed on four bulb biopsies taken before and one year after H. pylori eradication. At the same time, gastric pH was measured by 24-hr continuous intraluminal recording. H. pylori eradication was ascertained by means of concomitant negative CLO-test and histology performed both four weeks after the end of the eradicating treatment and at the one-year endoscopic control. After successful cure, all patients discontinued any antiulcer medication. The mean 24-hr gastric pH was 1.7 +/- 0.4 before and 1.6 +/- 0.4 after one year of H. pylori eradication (P = 0.75). DGM improved in three cases, worsened in four cases, and was unchanged in eight cases at the one-year control (P = 0.87). No correlation was found between 24-hr gastric pH and DGM (P = NS) both at baseline and one year after eradication. Our results show that neither circadian gastric acidity nor DGM change significantly one year after H. pylori eradication in duodenal ulcer patients. Thus, the disappearance of H. pylori infection does not determine any increase in gastric pH and any reversal of gastric-type epithelium in the duodenum.

Hypersecretory duodenal ulcer and Helicobacter pylori infection: a four-year follow-up study

BACKGROUND

About 10% of duodenal ulcer patients are characterized by gastric acid hypersecretion with normal gastrin values. Relapsing duodenal ulcer after Helicobacter pylori cure has been related to high acid output and maintenance antisecretory therapy has been suggested in hypersecretory duodenal ulcer patients. The role of Helicobacter pylori infection and the effects of Helicobacter pylori cure in hypersecretory duodenal ulcer patients still remain to be fully studied.

AIM

To study: a) whether gastric acid hypersecretion "per se" is a risk factor for duodenal ulcer recurrence; b) whether maintenance antisecretory therapy is necessary after eradication in hypersecretory duodenal ulcer patients.

PATIENTS

The study population comprised 8 hypersecretory duodenal ulcer patients, selected from a population of 79 Helicobacter pylori-positive duodenal ulcer patients.

METHODS

Hypersecretory duodenal ulcer patients were followed-up for at least 4 years after eradication. Gastric acid secretion was measured again 12 months after Helicobacter pylori eradication. Gastroscopy with histology was performed 3, 6, 12 and 36 months after treatment, 13C-urea breath test after 42 months; clinical questionnaires were completed every 6 months.

RESULTS

After eradication, despite a not significantly reduced high acid output (median value of basal acid output and pentagastrin-stimulated acid output, respectively, 23.1 mEq/h and 64.1 mEq/h before treatment vs 16 mEq/h and 49.7 mEq/h 12 months after treatment), all patients were free from symptoms, none of them had duodenal ulcer relapse or complications (7/8 before treatment), or needed antisecretory maintenance therapy, except for one patient taking non-steroidal anti-inflammatory drugs.

CONCLUSIONS

These findings, obtained in a selected population of hypersecretory duodenal ulcer patients with long-term follow-up, suggest that after successful Helicobacter pylori eradication gastric acid hypersecretion "per se" is not able to determine the recurrence of duodenal ulcer.

Conceivable mechanisms by which Helicobacter pylori provokes duodenal ulcer disease

A conceivable concept for the development of duodenal ulcers in Helicobacter pylori (H. pylori) infected subjects is presented in this chapter. The concept includes an explanation of the fact that only a minority of all H. pylori-infected subjects will develop a duodenal ulcer. Helicobacter pylori infection of the antrum induces a hypersecretion of gastric acid secretion, giving rise to gastric metaplasia in the duodenal bulb. This gastric metaplasia is a prerequisite for H. pylori colonization of the bulb. These events are common to all H. pylori-infected subjects. However, a much higher density of H. pylori bacteria and colonization with virulent organisms has been found in the bulb of duodenal ulcer patients, resulting in a much stronger inflammatory reaction with active duodenitis and an impaired bicarbonate secretion. These characteristics, together with acid hypersecretion, seem to be the important factors in evoking a duodenal ulcer.

The role of gastrin in ulcer pathogenesis

Duodenal ulcer patients are characterized by an antrum-predominant, body-sparing, nonatrophic Helicobacter pylori (H. pylori) gastritis, which results in increased gastrin release and increased acid secretion. The increased gastrin release is caused by the infection impairing the acid-mediated inhibitory control of gastrin release. The elevated levels of the gastrin stimulate the healthy uninflamed, non-atrophic acid-secreting region of the stomach to secrete excess amounts of acid. The increased gastrin also exerts trophic effects on the oxyntic mucosa, causing hyperplasia of both the enterochromaffin-like cells and the parietal cells. These trophic changes in the mucosa further enhance its ability to secrete acid. The increased acid secretion results in an increased duodenal acid load, causing gastric metaplasia of the duodenal bulb and eventually the development of ulceration. In H. pylori-infected subjects without duodenal ulceration, a different pattern of gastritis is seen. This includes atrophy of the antrum, which reduces the number of G-cells and thus the degree of hypergastrinaemia induced by the antral infection. There are usually also varying degrees of inflammation and atrophy of the acid-secreting mucosa, which impair its ability to secrete acid in response to gastrin stimulation. The combined effects of the atrophy of the antrum and the inflammation of the antrum of the body mucosa therefore prevent H. pylori-induced acid hypersecretion and may result in varying degrees of hypochlorhydria. The particular pattern of gastritis that a subject develops in response to H. pylori infection and their likelihood of developing a duodenal ulcer is likely to be determinded by host genetic factors plus dietary factors.

Changes in gastric acid secretion assayed by endoscopic gastrin test before and after Helicobacter pylori eradication

BACKGROUND

It remains controversial whether or not Helicobacter pylori infection causes altered gastric acid secretion. A novel test for evaluating gastric acid secretion (endoscopic gastrin test; EGT) has recently been developed.

AIM

To investigate by EGT the effects of H pylori eradication on the state of gastric acid secretion in patients with peptic ulcer.

METHODS

Twenty six patients with duodenal ulcer and 33 with gastric ulcer, for all of whom H pylori infection had been documented, were studied by EGT, histological examination of gastric mucosa, and measurement of plasma gastrin levels before and one and seven months after H pylori eradication.

RESULTS

In patients with duodenal ulcer, the mean EGT value before H pylori eradication was higher than that in H pylori negative controls, but it had decreased significantly seven months after the treatment. In contrast, the mean EGT value of patients with gastric ulcer before H pylori eradication was lower than that in H pylori negative controls, but it had increased one month after the treatment; this was followed by a slight decrease at seven months. In both groups, mean EGT values seven months after the treatment were not significantly different from the mean control value.

CONCLUSIONS

The reduced acid secretion in gastric ulcer patients and gastric acid hypersecretion in duodenal ulcer patients were both normalised after the clearance of H pylori.

Increase in apoptosis and decrease in ornithine decarboxylase activity of the gastric mucosa in patients with atrophic gastritis and gastric ulcer after successful eradication of Helicobacter pylori

OBJECTIVE

Recent reports have shown that patients infected with Helicobacter pylori (H. pylori) have a higher risk of gastric cancer. However, the mechanism of this increased risk is still unclear. In the gastric mucosa, the size of a continuously renewed population of cells is determined by the rates of cell production and of cell loss. Ornithine decarboxylase (ODC) activity is elevated in various gastrointestinal cancers and serves as a marker of mucosal proliferative activity. Apoptosis occurs throughout the gut and is associated with cell loss. Both cell proliferation and cell loss have important roles in H. pylori-associated gastric carcinogenesis. Therefore, we investigated the effect of H. pylori eradication on ODC activity and apoptosis in the gastric mucosa of patients with atrophic gastritis and gastric ulcers.

METHODS

Biopsy specimens of the gastric antrum were obtained at endoscopy from 17 H. pylori-positive gastric ulcers patients and 15 H. pylori-positive gastritis patients before and 4 wk after eradication therapy with amoxicillin, omeprazole, and a new anti-ulcer agent, ecabet sodium, and from 10 gastric ulcer patients in whom ulcer healed but H. pylori was left untreated. ODC activity and induction of apoptosis were determined immunohistochemically.

RESULTS

H. pylori was successfully eradicated with the triple therapy in 12 (80%) of 15 gastritis patients and 13 (76%) of 17 gastric ulcer patients. ODC activity was present in the gastric mucosa in 21 (84%) patients before eradication but in only four (16%) patients after successful eradication (p = 0.0005). The apoptotic index increased significantly (p = 0.0006) from 4.2% +/- 0.4% before treatment to 7.4% +/- 0.5% after successful eradication.

CONCLUSIONS

Successful eradication of H. pylori decreases mucosal ODC activity and increases apoptosis in the gastric mucosa. These findings indicate that by decreasing mucosal cell proliferation and increasing epithelial cell loss, H. pylori eradication may help decrease the subsequent risk of gastric cancer.

Gastro-oesophageal reflux disease and Helicobacter pylori: an intricate relation

Heartburn is a common symptom affecting 21-44% of the adult population on a monthly basis. Oesophagitis is less common, affecting 2% of individuals. Epidemiological studies have shown that patients with gastro-oesophageal reflux disease (GORD) have similar incidence rates of Helicobacter pylori infection as do controls. Some groups have reported that there is a lower incidence, deducing that infection does not cause, and in some way confers protection against GORD. Additional supportive evidence is available from reports of GORD development following successful H pylori eradication. The mechanisms involved are complicated. Individuals with H pylori induced pangastritis and subsequent hypochlorhydria may be protected whereas those with an antral predominant gastritis, as in duodenal ulcer disease, with an increased acid output may be prone to development of GORD. Recent evidence has linked H pylori infection with the development of inflammation of the gastric cardia---carditis. Reports are available which show that carditis is a frequent finding in patients with GORD. The incidence of both cardia and oesophageal carcinoma is increasing. The relation between GORD, carditis, intestinal metaplasia, and cardia carcinoma is unclear. Intestinal metaplasia may result from multifocal atrophic gastritis, linked to H pylori infection or from GORD and the development of Barrett's oesophagus. Long term follow up studies will be required to assess the malignant potential of these histological entities and whether or not H pylori infection has an aetiological role.

Helicobacter pylori modulation of gastric acid

Helicobacter pylori plays major causative roles in peptic ulcer disease and gastric cancer. Elevated acid secretion in patients with duodenal ulcers (DUs) contributes to duodenal injury, and diminished acid secretion in patients with gastric cancer allows carcinogen-producing bacteria to colonize the stomach. Eradication of H. pylori normalizes acid secretion both in hyper-secreting DU patients and hypo-secreting relatives of gastric cancer patients. Therefore, we and others have asked how H. pylori causes these disparate changes in acid secretion. H. pylori gastritis more or less restricted to the gastric antrum in DU patients is associated with increased acid secretion. This is probably because gastritis increases release of the antral acid-stimulating hormone gastrin and diminished mucosal expression of the inhibitory peptide somatostatin. Bacterial products and inflammatory cytokines including TNFalpha may cause these changes in endocrine function. Gastritis involving the gastric corpus tends to diminish acid secretion, probably because bacterial products and cytokines including IL-1 inhibit parietal cells. Pharmacological inhibition of acid secretion increases corpus gastritis in H. pylori-infected subjects, so it is envisaged that gastric hypo-secretion of any cause might become self-perpetuating. H. pylori-associated mucosal atrophy will also contribute to acid hypo-secretion and is more likely in when the diet is high in salt or lacking in antioxidant vitamins. Data on gastric acid secretion in patients with esophagitis are limited but suggest that acid secretion is normal or slightly diminished. Nevertheless, H. pylori infection may be relevant to the management of esophagitis because: (i) H. pylori infection increases the pH-elevating effect of acid inhibiting drugs; (ii) proton pump inhibitors may increase the tendency of H. pylori to cause atrophic gastritis; and (iii) successful eradication of H. pylori is reported to increase the likelihood of esophagitis developing in patients who had DU disease. Points (ii) and (iii) remain controversial and more work is clearly required to elucidate the relationship between H. pylori, acid secretion, gastric mucosa atrophy and esophagitis.

A new endoscopic method of gastric acid secretory testing

OBJECTIVE

To date, the effect of Helicobacter pylori on acid secretion remains controversial. To evaluate changes in the gastric acid secretory response before and after H. pylori eradication in a large number of patients, we devised a new endoscopic method of gastric acid secretory testing, the endoscopic gastrin test (EGT).

METHODS

In EGT, endoscopy was begun 15 min after intramuscular injection of 4 microg/kg tetragastrin. Gastric fluid secreted between 20 and 30 min after gastrin injection was aspirated and collected during endoscopic examination. The amount of acid in the sample collected over this 10-min period was estimated by titration and expressed in H+ mEq/10 min. Fifteen subjects underwent a conventional secretory test using a nasogastric tube (conventional method) and EGT on different days to assess the correlation between results obtained with the two methods. In 10 of these subjects, EGT was repeated under the same conditions to assess its reproducibility.

RESULTS

EGT values correlated very well with peak acid output determined by the conventional method (n = 15, r = 0.92) and had high reproducibility (n = 10, CV = 5.6). We noted that EGT takes just a little longer to perform than a routine endoscopic examination, and the influence of an endoscope in the stomach on acid secretion was not present.

CONCLUSION

The EGT should be very useful as a rapid, simple substitute for conventional secretory testing when repeated gastric secretory tests are required, especially in investigating the effect of H. pylori on acid secretion in a larger population.

Interleukin-8 enhances tetragastrin-stimulated acid secretion in vivo

Recent studies have demonstrated a relationship between cytokines and gastric acid secretion. However, details of the mechanism underlying that relationship have not been elucidated. For this study, an in vivo experiment was undertaken to investigate the possibility that IL-8 would be involved in the mechanism of gastric acid secretion. Gastric lumen-perfused rats were prepared and the stomachs were perfused with a saline solution. The effluent was collected at 15-min intervals and assayed for titratable acid against 0.01 M NaOH. IL-8 (200 ng/rat) given intravenously did not influence basal acid output in rats. However, when IL-8 was administered by injection during continuous tetragastrin infusion (4 microg/kg/hr) acid output increased significantly (P < 0.01). The acid output during the first hour following IL-8 injection was 43.6% higher than prior to the injection. Acid output during the second hour was lower than during the first hour. However, successive injection of IL-8 again increased tetragastrin-stimulated acid output by 23.4% (P < 0.05). IL-8 injection did not change histamine-stimulated acid output. The results indicate that IL-8 has the effect of enhancing gastrin-stimulated acid secretion and might have an important role in the pathophysiology of gastric acid secretion in vivo.

Role of gastric acid in the aetiology of dyspeptic disease and dyspepsia

The main diseases associated with dyspepsia are peptic ulcer disease, gastro-oesophageal reflux disease and non-ulcer dyspepsia. Increased gastric acid secretion is a characteristic of most duodenal ulcer patients and of a small minority of non-ulcer dyspepsia and gastro-oesophageal reflux disease patients. Although acid secretion is normal in most gastro-oesophageal reflux disease patients, the condition is mainly the result of excess exposure of the distal oesophagus to acid refluxing from the stomach. Increased mucosal sensitivity to acid is involved in the aetiology of dyspeptic symptoms in the majority of patients with peptic ulcer disease and gastro-oesophageal reflux disease, and in a minority of non-ulcer dyspepsia subjects. Gastric acid, therefore, plays an important role in both the aetiology of dyspeptic diseases and in the aetiology of dyspeptic symptoms.

Decreased prevalence of Helicobacter pylori infection in gastroesophageal reflux disease

BACKGROUND

An increased incidence of reflux esophagitis has been reported after eradication of H. pylori in patients with duodenal ulcer. To determine if H. pylori is associated with lower rates of esophagitis, we studied the prevalence of H. pylori infection in patients with and without reflux esophagitis and a subgroup of patients with concomitant peptic ulcer disease.

METHODS

Patients who underwent esophagogastroduodenoscopy and had diagnostic testing for H. pylori over a 30-month period were studied. H. pylori infection was determined by rapid urease testing, gastric histopathology, or serology. Reflux esophagitis was determined by endoscopic and/or histologic criteria.

RESULTS

Of 514 patients, 39.5% had H. pylori infection and 22.2% had reflux esophagitis. The prevalence of H. pylori infection in patients with reflux esophagitis was 30.7%, compared with 42.0% in patients without esophagitis (p = 0.039). The odds ratio for esophagitis risk with H. pylori infection was 0.61 (95% CI, 0.39-0.95). Neither patient age nor gender affected H. pylori prevalence. In patients with duodenal ulcer, H. pylori was present in 36.4% of patients with esophagitis and in 69.2% of patients without esophagitis (p = 0.018). The odds ratio for esophagitis with H. pylori infection in these patients was 0.25 (95% CI, 0.09-0.73).

CONCLUSIONS

Our study demonstrates that H. pylori infection is significantly less prevalent in patients with reflux esophagitis and may protect against its development. In duodenal ulcer patients, this effect was more dramatic. Further study is required to confirm these findings and elucidate mechanisms underlying possible beneficial effects of H. pylori.

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.

Different management for Helicobacter pylori positive and negative patients with gastro-oesophageal reflux disease?

Available evidence would suggest that Helicobacter pylori infection does not contribute to the pathogenesis of gastro-oesophageal reflux disease. The prevalence of H pylori infection in patients with reflux disease is no greater than that in control populations. There are some data suggesting that the organism has a protective role: patients with duodenal ulcers develop reflux disease after H pylori eradication, whereas in patients with oesophageal reflux those with H pylori infection have less severe reflux changes. There is also evidence indicating that the presence of H pylori augments the anti-secretory properties of both the H2 receptor antagonists and proton pump inhibitors (PPIs), suggesting that eradication therapy may not be beneficial. However, the considerable recent interest in the association between H pylori and reflux disease has largely been generated by studies outlining the interactions between H pylori infection and acid suppression in the long term. In H pylori positive patients, therapy with PPIs is associated with a proximal extension of the infection and its associated gastritis. In addition long term PPI therapy is reported to be associated with an accelerated development of atrophic gastritis, suggesting that H pylori should be diagnosed and treated. Although these latter findings in particular need confirmation, H pylori eradication therapy should be considered in this patient group, at least until there is evidence to the contrary.

Influence of bacterial CagA status on gastritis, gastric function indices, and pattern of symptoms in H. pylori-positive dyspeptic patients

OBJECTIVE

To date, little is known about a possible relationship between H. pylori-related disturbances of gastric function and the bacterial virulence. The aim of this study was to assess whether certain gastric function indices as well as the pattern of symptoms in nonulcer dyspepsia (NUD) are related to CagA status.

METHODS

A total of 56 consecutive patients with NUD (38 H. pylori-positive and 18 H. pylori-negative) were studied. Dyspeptic symptoms were categorized according to the predominant complaints and scored for severity and frequency. In all subjects, basal and pentagastrin-stimulated acid secretion, fasting and meal-induced gastrin release, fasting serum pepsinogen I (PG I) levels, and gastric emptying of solids were determined. CagA status was determined by assaying serum CagA IgG antibodies by western blotting.

RESULTS

Eighteen of 38 (47%) H. pylori-positive dyspeptics were CagA seropositive. Type and severity of dyspeptic symptoms did not significantly differ between CagA-positive and CagA-negative dyspeptics nor between H. pylori-positive and negative patients. Among the gastric function indices studied, only meal-stimulated gastrin was significantly influenced by CagA status (peak gastrin 129.9 [44.1] vs 99.1 [48.6] pg/ml in CagA-positive and negative NUD, respectively), but this was not accompanied by any significant modification of basal or stimulated acid secretion or gastric emptying of solids. The activities of both antral and corpus gastritis in NUD harboring CagA-positive strains were significantly higher than those of CagA-negative NUD. Accordingly, serum PG I levels were significantly higher in CagA-positive than CagA-negative or H. pylori-negative dyspeptics.

CONCLUSIONS

These findings support a role for CagA status in influencing the activity and perhaps the distribution of gastritis in NUD, as well as the degree of gastrin response to a meal; however, this is not accompanied by disturbances of acid secretion or gastric emptying or by differences in the type and severity of symptoms.

Effects of Helicobacter pylori gastritis on gastric secretion in healthy human beings

Helicobacter pylori gastritis is common, but effects on gastric secretion are not well understood. We measured basal and pentagastrin-stimulated gastric acidity, pepsin activity, and fluid output, as well as serum gastrin concentrations and H. pylori antibody levels, before and after treatment of H. pylori gastritis in 28 men and women. Subjects were studied before and 1 and 3 mo after a course of bismuth, metronidazole, and tetracycline. Elimination of H. pylori gastritis, accomplished in 14 subjects, increased basal and pentagastrin-stimulated gastric acidity (by 15 meq/l) and basal acid output significantly (by 2.1 meq/h 1 mo after therapy). Elimination of H. pylori had an opposite effect on pepsin secretion, significantly decreasing pepsin output by 30%. Elimination of H. pylori significantly reduced nonparietal fluid output by 35%, without affecting fluid output from parietal cells. Serum gastrin and H. pylori antibody levels declined significantly after elimination of H. pylori. None of these changes was observed in 14 subjects whose H. pylori gastritis was resistant to antimicrobial therapy. In summary, eradication of H. pylori infection increases gastric acidity by reducing nonparietal gastric secretion from peptic and other cells.

Effects of Helicobacter pylori eradication on gastric function indices in functional dyspepsia. A prospective controlled study

BACKGROUND

To date, it is unclear whether Helicobacter pylori infection is associated with disturbances of gastric emptying or acid secretion in patients with functional dyspepsia (FD). Our aim was to investigate whether, in the long run, cure of H. pylori infection significantly influences gastric emptying of solids, acid secretion, and gastrin and pepsinogen I (PGI) release in patients with FD.

METHODS

Thirty-eight consecutive H. pylori-positive patients with FD, whose complaints were scored for severity and frequency on the basis of a validated symptom questionnaire, were initially enrolled in the study. They were randomized to receive an eradicating regimen consisting of omeprazole plus clarithromycin and tinidazole for 1 week or full-dose ranitidine for 3 weeks. In 33 patients (18 H. pylori-cured and 15 with persistent infection) basal and pentagastrin-stimulated acid secretion, fasting and meal-induced gastrin concentrations, fasting serum PGI levels, and gastric emptying of solids were determined before and 6 months after therapy.

RESULTS

In the 18 H. pylori-cured patients meal-induced gastrin and fasting PGI levels were significantly reduced after 6 months as compared with pretreatment values (peak serum gastrin, 76.0 +/- 23.4 versus 111.9+/-37.4 pg/ml; PGI, 57.1+/-23.4 versus 72.9+/-29.1 ng/ml), whereas they remained virtually unchanged in the 15 patients with persistent infection. In contrast, both basal and stimulated acid secretion and gastric emptying time of solids remained unmodified over time in both groups of patients.

CONCLUSIONS

We confirm that also in patients with functional dyspepsia H. pylori eradication in the long run significantly reduces gastrin and PGI release as a result of improvement in the underlying antral gastritis, but this is not accompanied by modifications of gastric emptying of solids or acid secretion.

Eradication of Helicobacter pylori infection in the management of patients with dyspepsia and non-ulcer dyspepsia

Although H. pylori infection has been recognized as a major etiological agent for the development of chronic active gastritis, duodenal ulcer and benign non-NSAID related gastric ulcer, its role in the development of symptoms in patients with dyspepsia remains uncertain. Results from population-based epidemiological studies have been conflicting regarding a causal link between H. pylori infection and dyspepsia. Abnormalities in gastric acid secretion may exist in some dyspeptic patients. Whether disordered gastric motility seen in dyspeptic patients is related to the infection is not clear based on the results in the literature. Numerous clinical trials have been undertaken to eradicate H. pylori infection and improve the symptoms in dyspeptic patients; however, the results have been discrepant between studies. Many published studies suffer from methodological problems that have made interpretation difficult. Large, well-conducted, randomized, placebo-controlled, clinical trials with long-term follow-up are needed to justify the beneficial effect of H. pylori eradication treatment in dyspeptic patients seen in some small studies. H. pylori eradication therapy is cost-effective in H. pylori-infected dyspeptic patients although this benefit may take a long time to accrue, especially in younger patients.