Inappropriate hypergastrinaemia in asymptomatic healthy subjects infected with Helicobacter pylori

Fundal gastritis as a potential cause of reflux oesophagitis

The transient lower oesophageal sphincter relaxations which allow reflux may be due to altered afferent pathways from the fundus. We aimed to determine whether fundal inflammation is the underlying cause. Two endoscopic biopsies were taken from each of the gastric antrum and fundus in 25 asymptomatic controls with a normal endoscopy (median age 54 range 13-83 years), and 33 patients with erosive oesophagitis (median age 52, 11-78 years). No patient had taken acid suppression therapy or antibiotics for at least 1 month. Sections were stained with haematoxylin and eosin and Giemsa stain and examined in a blinded fashion by one pathologist for the presence of gastritis (Sydney classification) and Helicobacter pylori. Chronic gastritis was common in both groups, but was usually mild. In Helicobacter pylori-negative subjects, there was significantly less chronic gastritis in the antrum and the fundus in oesophagitis patients than in controls (p < 0.05). When present, gastric atrophy was usually antral and mild in severity. There was no difference in the incidence of gastric atrophy in patients with oesophagitis compared with controls (24% compared with 40%; p > 0.05). Chronic gastritis is not more common in patients with oesophagitis, and is unlikely to play a part in the pathogenesis of this disease.

Helicobacter pylori and gastroesophageal reflux disease: lack of influence of infection on twenty-four-hour esophageal pH monitoring and endoscopic findings

The precise role of Helicobacter pylori infection in gastroesophageal reflux disease (GERD) is a matter of intense debate. Twenty-four-hour esophageal pH monitoring has a higher accuracy than endoscopy for the diagnosis of GERD, but the correlation between H. pylori infection and esophageal pH-metric parameters has almost never been assessed. Therefore, we evaluated the relationship between the infection and the presence of disturbances not only in endoscopy but also in 24-hour esophageal pH monitoring. One hundred consecutive patients undergoing 24-hour esophageal pH monitoring because of symptoms suggestive of GERD were included in the study. Esophageal manometry was carried out to study the position and the pressure of the lower esophageal sphincter (LES). Prevalence of H. pylori infection was evaluated by histology (hematoxylin and eosin stain) and rapid urease test. The mean age of the patients was 50 +/- 15 years; 50% were men and 56% had an abnormal pH-metry (DeMeester score more than 14.7). The prevalence of H. pylori in patients with abnormal pH-metry was 57% (95% CI, 42-70%) and was 52% (95% CI, 39-64%) in those with normal pH-metry (nonsignificant differences [NS]). In the multivariate analysis, H. pylori infection did not correlate with an abnormal pH-metry (odds ratio, 0.8; 95% CI, 0.4-1.8; NS). The proportion of cases with abnormal pH-metry among infected patients was 54% (95% CI, 41-66%) and was 59% (95% CI, 44-72%) among uninfected patients (NS). Mean values of pH-metric parameters (+/-SD), respectively for H. pylori-positive and -negative patients, were total score (30 +/- 33 vs. 36 +/- 38), number of reflux episodes (7 +/- 7 vs. 11 +/- 11), number of episodes more than 5 minutes (3.7 +/- 5 vs. 3.8 +/- 5), longest reflux episode (2.4 +/- 2 minutes vs. 3.1 +/- 3 minutes), and fraction time (%) with pH less than 4 (total, 6 +/- 7 vs. 6.8 +/- 8; upright, 3.9 +/- 4 vs. 4.5 +/- 5; supine, 7.4 +/- 12 vs. 7.2 +/- 10) (all findings were NS). Endoscopic findings, respectively for H. pylori-positive and -negative, were hiatus hernia (41% vs. 41%), endoscopic esophagitis (Savary-Miller) (54% vs. 46%), and Barrett's esophagus (15% vs. 11%) (all findings were NS). Finally, differences were not demonstrated in the pressure of the lower esophageal sphincter (12 +/- 8 mmHg vs. 14 +/- 12 mmHg) among H. pylori-positive and -negative patients. H. pylori infection is not associated with gastroesophageal reflux disease, as evaluated endoscopically and with 24-hour esophageal pH monitoring.

Helicobacter pylori augments the acid inhibitory effect of omeprazole on parietal cells and gastric H(+)/K(+)-ATPase

BACKGROUND

In duodenal ulcer patients, intragastric acidity during omeprazole treatment is significantly lower before Helicobacter pylori eradication than after cure.

AIMS

To determine if H pylori enhances the acid inhibitory potency of omeprazole in isolated parietal cells and on H(+)/K(+)-ATPase.

METHODS

Rat parietal cells and pig gastric membrane vesicles enriched in H(+)/K(+)-ATPase activity were incubated with H pylori and the H pylori fatty acid cis 9,10-methyleneoctadecanoic acid (MOA), and the inhibitory effects of omeprazole on parietal cell acid production, H(+)/K(+)-ATPase enzyme activity, and ATPase mediated proton transport were assessed.

RESULTS

In isolated parietal cells, H pylori and MOA increased the acid inhibitory potency of omeprazole 1.8 fold. H pylori did not affect the inhibitory potency of omeprazole on H(+)/K(+)-ATPase enzyme activity. In proton transport studies, H pylori (intact bacteria and sonicate) and MOA accelerated the onset of the inhibitory effect of omeprazole and enhanced the proton dissipation rate in response to omeprazole. H. pylori itself increased proton permeability at the vesicle membrane.

CONCLUSION

Our results show that H pylori augments the acid inhibitory potency of omeprazole in parietal cells and enhances omeprazole induced proton efflux rate from gastric membrane vesicles. We suggest that omeprazole unmasks the permanent effect of H pylori on proton permeability at the apical parietal cell membrane, which is counteracted in the absence of a proton pump inhibitor by a reserve H(+)/K(+)-ATPase capacity.

Circulating cytokines and gastrin levels in asymptomatic subjects infected by Helicobacter pylori (H. pylori)

The pathophysiology of hypergastrinemia in H. pylori infection has been largely investigated and different reports clearly show that the infected antrum has a marked inflammatory response with a suggestive local production of cytokines. Notwithstanding, a few data are available on the circulating levels of cytokines and gastrin in the asymptomatic people carrying H. pylori infection. Thus, aim of the study was to evaluate circulating proinflammatory cytokines [Interleukin (IL)-8, Interleukin (IL)-10, Interferon (IFN)-gamma, and Tumor Necrosis Factor (TNF)-alpha] and gastrin levels in H. pylori positive asymptomatic subjects vs. H. pylori negative ones. To this end, thirty healthy volunteers with no digestive symptoms or systemic disease were enrolled and H. pylori infection was identified by a 13C-urea breath test. Plasma levels of gastrin were determined using the RIA kit whereas IL-8, TNF-alpha, IL-10, and IFN-gamma levels in serum were measured with a solid-phase ELISA. Fifteen infected people showed significantly higher gastrin and TNF-alpha levels than uninfected subjects. On the contrary, IL-8 levels were significantly higher in the uninfected subjects than in H. pylori positive ones (P < 0.0422). IFN-gamma and IL-10 circulating levels were not affected by H. pylori presence, being not significantly different in the two groups.

Review article: gastrin and colorectal cancer

The polypeptide hormone gastrin was identified nearly a hundred years ago and its role in the regulation of acid secretion is well established. Gastrin also acts as a growth factor and is trophic for the normal gastric oxyntic mucosa. This growth promoting action has led to the extensive investigation of its role in carcinogenesis, in particular colorectal neoplasia. The relationship between gastrin and colorectal adenocarcinoma has been subject to controversy, however the findings from several recent studies have resulted in a clearer understanding of the mechanism of action of gastrin in this is common cancer. The majority of colorectal cancers produce their own gastrin, which may act in an autocrine manner. The tumour cells also express gastrin/CCKB receptors (and/or a combination of isoforms) which mediate the proliferative action. This locally produced gastrin gives rise to a small increase in systemic gastrin levels. Autocrine gastrin may also have a role in tumour development, as expression occurs early in the adenoma-carcinoma sequence. In addition, several studies using animal models have shown that systemic hypergastrinaemia promotes the proliferation of both normal and neoplastic colonic epithelium. Hyperproliferative colonic epithelium in the presence of hypergastrinaemia has been recorded in humans and a well-designed epidemiological study has demonstrated an increased incidence of colorectal cancer. Gastrin is a potential therapeutic target in the treatment of colorectal cancer and several approaches have been assessed. Receptor antagonists and antisecretory agents have been demonstrated to be ineffectual. Novel methods of inhibition, including the use of anti-gastrin antibodies, are currently being evaluated.

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.

Altered gastrin regulation in mice infected with Helicobacter felis

Altered gastrin expression associated with Helicobacter pylori infection may contribute to the pathogenesis of peptic ulcer disease or gastric cancer in man, but gastrin has not been investigated in a murine model of Helicobacter infection. C57BL/6 mice were inoculated with Helicobacter felis and examined after 4-21 weeks for G and D cell numbers, antral gastrin and somatostatin mRNA, and luminal pH. In H. felis-infected mice, gastrin mRNA declined at four and six weeks after infection to 57% and 23%, respectively, of uninfected control values. Concurrently, somatostatin mRNA showed no change at four weeks and a modest 25% decrease at six weeks after infection. Similar reductions were noted in G and D cell numbers, resulting in a decrease in the G/D cell ratio after mice were infected with H. felis. Infected animals also showed a loss of parietal and chief cells, and an increased gastric pH. H. felis infection in C57BL/6 mice leads to an early suppression of G cell number and gastrin mRNA. These changes precede an alteration in somatostatin cell number and mRNA and, coupled with reductions in parietal and chief cells, may contribute both to severe impairment of gastric acid output and the potential for carcinogenic processes.

Effect of age and Helicobacter pylori infection on gastric acid secretion

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Helicobacter pylori and gastroesophageal reflux disease

The nature of the relationship between Helicobacter pylori (Hp) infection and gastroesophageal reflux disease (GERD) remains unclear. This article reviews the current body of knowledge regarding the association between these two common entities. The authors examine the potential interactions of Hp and GERD from epidemiologic and pathophysiologic viewpoints and summarize and critique the prevalence and eradication studies that have been performed to date. Special consideration is given to the possible effects that long-term use of proton pump inhibitors may have on Hp gastritis.

Impact of Helicobacter pylori infection on serum gastrin in haemodialysis patients

BACKGROUND

Helicobacter pylori infection is associated with increased gastrin release in patients with normal renal function. Hypergastrinaemia is a common finding in haemodialysis patients and, in many cases, may be linked to H. pylori infection. The aim of this study was to examine the effect of H. pylori infection, and its eradication, on elevated gastrin levels in haemodialysis patients.

METHODS

Eighty-nine dyspeptic patients were included in the study. While 44 patients had normal renal function, the remaining 45 were end-stage renal failure patients. Patients were assigned to one of four groups according to their H. pylori and renal function status. Infected patients were re-evaluated after 2 months following eradication treatment. Serum gastrin levels were measured in these groups both before and after eradication treatment.

RESULTS

Haemodialysis patients with H. pylori infection had higher serum gastrin levels than did H. pylori negative haemodialysis patients (321+/-131 pg/ml vs 154+/-25 pg/ml) (P<0.05). Mean serum gastrin concentration was 152+/-21 pg/ml in the non-uraemic H. pylori-positive group. This value was 58+/-17 pg/ml in the non-uraemic H. pylori-negative group (P<0.05). There were significant decreases in serum gastrin levels from pre- to post-eradication of H. pylori in the infected haemodialysis and non-uraemic patient groups (312+/-131 pg/ml to 179+/-85 pg/ml and 152+/-21 pg/ml to 72+/-2.4 pg/ml respectively, P<0.05). Four patients in group Ib and 5 patients in group IIb who had persistent infection did not have a decrease in serum gastrin level. All patients with successful eradication had a decrease in serum gastrin concentration.

CONCLUSION

Our findings suggest that H. pylori infection contributes to hypergastrinaemia in haemodialysis patients. More research is needed regarding the clinical consequences of hypergastrinaemia in these individuals.

Significance of serum pepsinogens and their relationship to Helicobacter pylori infection and histological gastritis in dialysis patients

BACKGROUND

Previous investigations reported that patients undergoing dialysis therapy had significantly higher serum pepsinogen (PG) levels than patients with normal renal function. However, in dialysis patients, the relationship between serum PG levels and Helicobacter pylori infection remains unknown.

METHODS

Sixty three maintenance dialysis patients (54 haemodialysis and nine continuous ambulatory peritoneal dialysis) who required endoscopic examination were enrolled in the study. Sixty four age- and sex-matched patients with normal renal function served as controls. We performed endoscopic examination and obtained both the gastric antral and corpus mucosa for histopathological evaluation and H. pylori identification. Twenty three patients on dialysis underwent H. pylori eradication therapy.

RESULTS

In dialysis patients, H. pylori-positives had significantly higher serum PG II levels than H. pylori-negatives (26.6+/-21.5 vs 14.1+/-7.1 ng/ml, P<0.05), but no significant difference was found in serum PG I between H. pylori-positives and H. pylori-negatives (228.8+/-158.5 vs 179. 4+/-113.5 ng/ml). There was no significant difference in serum PG II between dialysis patients and controls (19.9+/-16.5 vs 18.6+/-14.9 ng/ml), while serum PG I levels were significantly higher in dialysis patients than in controls (201.7+/-136.8 vs 77.6+/-85.8 ng/ml, P<0.05). Serum PG II levels, but not those of PG I, significantly correlated with the inflammation and activity scores of antrum in dialysis patients, and these scores were highly influenced by H. pylori infection. Dialysis patients in whom H. pylori was eradicated successfully showed significant reductions of serum PG II levels but not of PG I.

CONCLUSIONS

In dialysis patients, high serum levels of PG II, but not PG I, are significantly related to H. pylori infection and mucosal inflammation. A significant decrease in serum PG II levels could be used as a predictor of the eradication of H. pylori infection in dialysis patients.

Helicobacter pylori-induced gastritis may contribute to occurrence of postprandial symptomatic hypoglycemia

In our clinical experience, postprandial symptomatic hypoglycemic (PSH) patients with H. pylori gastritis showed a substantial improvement in their hypoglycemic symptoms after the eradication of H. pylori. Therefore, in this study we have investigated whether H. pylori gastritis may contribute to the occurrence of PSH. For this purpose, we have evaluated the following parameters in 12 PSH patients with H. pylori gastritis before and one month after the eradication therapy: (1) the number and severity of PSH attacks that occurred in a one-month period using a 30-day diary, (2) the total symptom score following a mixed meal using a visual analog scale questionnaire (VASQ), and (3) the glucose and insulin responses to the mixed meal. After the eradication of H. pylori, the serum insulin responses at 30 and 60 min decreased (P < 0.001 in both), whereas the plasma glucose levels at 150, 180 and 210 min increased significantly (P < 0.001 for 180 min and P < 0.01 in others) following the mixed meal. The number and severity score of PSH attacks that occurred in a one-month period and the area under curve for symptom score in VASQ decreased significantly (P < 0.001 in all). These results suggest that H. pylori gastritis may contribute to the occurrence of PSH.

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.

The effect of Helicobacter pylori eradication on intragastric pH during dosing with lansoprazole or ranitidine

BACKGROUND

The antisecretory effect of omeprazole on intragastric pH is decreased in the absence of Helicobacter pylori.

AIM

To investigate the effect of H. pylori eradication on intragastric pH during lansoprazole or ranitidine dosing in 41 asymptomatic H. pylori-positive subjects.

METHOD

Two groups of healthy H. pylori-positive volunteers were investigated. One group was dosed with lansoprazole 30 mg at 08.00 hours for at least 8 days, before and after 2 weeks of placebo-controlled double-blind eradication therapy using ranitidine bismuth citrate 400 mg b.d. and clarithromycin 500 mg b.d. The other group was dosed with ranitidine 300 mg at 23.00 hours for at least 8 days using the same trial design. An upper endoscopy was performed to establish H. pylori status by rapid urease test, culture and histology before both periods of dosing. Twenty-four hour intragastric pH recording was performed on the final day of all periods of dosing.

RESULTS

H. pylori eradication significantly decreased the intragastric pH reached during lansoprazole treatment throughout all periods of the day. Intragastric pH during ranitidine treatment was not affected by H. pylori eradication, except for the late-night period.

CONCLUSION

H. pylori eradication has a more pronounced effect on the acid-inhibiting properties of lansoprazole than on those of ranitidine.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Gastroduodenal ulcers: causes, diagnosis, prevention and treatment

During the past decade, new acid antisecretory drugs have been developed, and our understanding of the mechanisms of mucosal ulceration has been broadened. However, the major change has been an appreciation of the role of Helicobacter pylori in peptic ulcer disease.

A placebo-controlled trial to assess the effects of 8 days of dosing with rabeprazole versus omeprazole on 24-h intragastric acidity and plasma gastrin concentrations in young healthy male subjects

BACKGROUND

Rabeprazole (LY307640, E3810) is a new, potent, proton pump inhibitor. A single daily 20 mg dose significantly decreases 24-h intragastric acidity. There are no data currently available directly comparing the effect of rabeprazole on 24-h acidity with established proton pump inhibitors.

AIM

To compare the effects of rabeprazole 20 mg o.m. and omeprazole 20 mg o.m. on 24-h intragastric acidity and plasma gastrin concentration in a randomized, double-blind, placebo-controlled trial, in healthy H. pylori-negative subjects.

METHODS

Twenty-four healthy male volunteers, negative for H. pylori infection by serology and 13C-urea breath test, were studied on the 1st and 8th day of dosing with either placebo, rabeprazole 20 mg or omeprazole 20 mg, once each morning, in a crossover fashion. On days 1 and 8, hourly intragastric acidity was measured by gastric aspiration for 24 h from 08.00 hours. On day 8, plasma gastrin concentrations were also measured hourly from 08.00 to 24.00 hours, then every 2 h thereafter.

RESULTS

A single dose of both rabeprazole and omeprazole significantly decreased 24-h intragastric acidity compared with placebo. The 24-h acidity on day 1 was significantly decreased for rabeprazole compared with omeprazole (331 vs. 640 mmol.h/L, P < 0.001), resulting in a significantly higher median 24-h intragastric pH and longer times at which intragastric pH was > 3 and > 4. On day 8 of dosing, the decrease in 24-h intragastric acidity was greater with rabeprazole than with omeprazole, but the difference was not statistically significant (160 vs. 218 mmol.h/L, P = 0.1). However, 24-h plasma gastrin concentration (1687 vs. 1085 pmol.h/L. P < 0.01) and percentage time that intragastric pH was > 3 (69 vs. 59%, P = 0.008) and > 4 (60 vs. 51%, P = 0.03) were significantly greater.

CONCLUSIONS

Rabeprazole 20 mg once daily has a significantly faster onset of antisecretory activity than omeprazole 20 mg once daily. After 8 days the differences in intragastric pH > 3 and > 4 holding times persisted, but there was no significant difference in 24-h acidity.

Stimulation of pepsinogen release from chief cells by Helicobacter pylori: evidence for a role of calcium and calmodulin

To define the mechanisms by which Helicobacter pylori stimulates pepsinogen secretion, the in vitro release of pepsinogen was studied using a preparation of pig chief cell monolayers. Helicobacter pylori induced a time- and concentration-dependent release of pepsinogen into the medium, with about a three-fold increase in pepsinogen secretion over controls found after 45 min of incubation. 3x10(7) H. pylori produced 50% of the maximal response found at a H. pylori count of 2x10(8). The action of H. pylori did not depend on the presence of the vacuolating toxin (vacA) and the cytotoxin-associated protein (cagA). Dibutyryl-cAMP and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate also markedly stimulated pepsinogen secretion and enhanced the stimulatory effect of H. pylori. Helicobacter pylori-stimulated pepsinogen release was inhibited by lanthanum and the calmodulin antagonist W-7, but not by the L-type Ca2+ channel blocker nifedipine, TMB-8, an agent that blocks the release of Ca2+ from intracellular stores, the protein kinase C inhibitor staurosporine and the protein kinase A inhibitor H-8. It is suggested that H. pylori directly stimulates pepsinogen release from gastric chief cells and that this effect is mediated via the calcium/calmodulin messenger branch.

Acid-induced expression of an LPS-associated gene in Helicobacter pylori

To investigate urease-independent mechanisms by which Helicobacter pylori resists acid stress, subtractive RNA hybridization was used to identify H. pylori genes whose expression is induced after exposure to acid pH. This approach led to the isolation of a gene that encoded a predicted 34.8kDa protein (WbcJ), which was homologous to known bacterial O-antigen biosynthesis proteins involved in the conversion of GDP-mannose to GDP-fucose. An isogenic wbcJ null mutant strain failed to express O-antigen and Lewis X or Lewis Y determinants and was more sensitive to acid stress than was the wild-type strain. Qualitative differences in LPS profiles were observed in H. pylori cells grown at pH 5 compared with pH 7, which suggests that H. pylori may alter its LPS structure in response to acidic pH. This may be an important adaptation facilitating H. pylori colonization of the acidic gastric environment.

Hypergastrinaemia during long-term omeprazole therapy: influences of vagal nerve function, gastric emptying and Helicobacter pylori infection

AIM

elucidate the mechanisms that lead to severe hypergastrinaemia during long-term omeprazole therapy for gastro-oesophageal reflux disease (GERD).

PATIENTS AND METHODS

A total of 26 GERD patients were studied during omeprazole maintenance therapy. Twelve patients with severe hypergastrinaemia (gastrin > 400 ng/L) were compared with 14 control patients (gastrin < 300 ng/L). Helicobacter pylori serology and a laboratory screen were obtained in all patients. Gastric emptying was scored by the evidence of food remnants upon endoscopy 12 h after a standardized meal. Gastric antrum and corpus biopsies were analysed for histological parameters, as well as somatostatin and gastrin concentrations. All patients underwent a meal-stimulated gastrin test and the hypergastrinaemia patients also underwent a vagal nerve integrity assessment by pancreatic polypeptide testing (PPT).

RESULTS

Severe hypergastrinaemia patients had a longer duration of treatment (80 vs. 55 months; P = 0.047) and were characterized by a higher prevalence of H. pylori infection (9/12 vs. 2/14, P = 0.004), corpus mucosal inflammation and atrophic gastritis (P < 0.04). This was reflected in lower serum pepsinogen A concentrations (mean +/- S.E.M. 53.6 +/- 17.9 vs. 137 +/- 16.0 mg/L, P = 0.03), pepsinogen A/C ratio (1.8 +/- 0.3 vs. 4.1 +/- 0.6, P = 0.005) and mucosal somatostatin concentrations (2.75 +/- 0.60 vs. 4.48 +/- 1.08 mg/g protein, P = 0.038). Two patients in the hypergastrinaemia group had signs of delayed gastric emptying, but none in the normogastrinaemia group did (P = N.S.). In addition, both groups had a normal meal-stimulated gastrin response.

CONCLUSION

Severe hypergastrinaemia during omeprazole maintenance therapy for GERD is associated with the duration of therapy and H. pylori infection, but not with abnormalities of gastric emptying or vagal nerve integrity.

The seroprevalence of cagA-positive Helicobacter pylori strains in the spectrum of gastroesophageal reflux disease

BACKGROUND & AIMS

The role of Helicobacter pylori in the pathogenesis of gastroesophageal reflux disease (GERD) is unknown. We determined the prevalence of cagA-positive (cagA+) H. pylori strains in patients with GERD or its complications compared with controls of similar age.

METHODS

A total of 153 consecutive patients with GERD, Barrett's esophagus, and Barrett's esophagus complicated by dysplasia or adenocarcinoma were compared with 57 controls who underwent upper endoscopy for reasons other than GERD. H. pylori infection and CagA antibody status were determined by histology and enzyme-linked immunosorbent assay.

RESULTS

H. pylori prevalence was lower (34%) in patients with GERD and its sequelae than in the control group (45.6%)(P = 0.15). Regardless of the group, increasing age was associated with higher prevalence of H. pylori (P = 0.003). When compared with controls (42.3%), the prevalence of cagA+ H. pylori strains decreased (P = 0.008) in patients with more severe complications of GERD (GERD, 36.7% [nonerosive GERD, 41.2%; erosive GERD, 30.8%]; Barrett's esophagus, 13.3%; and Barrett's with adenocarcinoma/dysplasia, 0%).

CONCLUSIONS

Prevalence of H. pylori in patients with GERD and its sequelae was lower but not significantly different than that of a control group. However, patients carrying cagA+ strains of H. pylori may be protected against the complications of GERD, especially Barrett's esophagus and its associated dysplasia and adenocarcinoma.

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.

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The acid response to gastrin distinguishes duodenal ulcer patients from Helicobacter pylori-infected healthy subjects

BACKGROUND & AIMS

Helicobacter pylori-induced hypergastrinemia is accompanied by increased acid secretion in patients with duodenal ulcer (DU) but not in infected healthy volunteers. The aim of this study was to investigate the mechanism underlying this difference.

METHODS

Thirty-four H. pylori-negative and 20 H. pylori-positive healthy volunteers and 15 H. pylori-positive patients with DU were studied. Maximal acid output and sensitivity to gastrin (gastrin concentration required to achieve 50% maximal acid output) were assessed by examining the dose response to gastrin 17. Inhibitory control was tested by comparing the maximal acid response to cholecystokinin octapeptide with that for gastrin 17.

RESULTS

Sensitivity to gastrin was similar in patients with DU (median, 69.5 ng.L-1; range, 26.2-142) and H. pylori-negative healthy volunteers (median, 82.2 ng.L-1; range, 17.7-410); H. pylori-positive healthy volunteers were less sensitive than either (164.5 ng.L-1; range, 44.8 to > 3360 ng.L-1). Patients with DU had higher maximal acid output (51.2 mmol.h-1; range, 30.8-73.7 mmol.h-1) than either infected healthy volunteers (37.8 mmol.h-1; range, 0.0-65.0 mmol.h-1; P < 0.04) or uninfected healthy volunteers (35.3 mmol.h-1; range, 21.3-67.3 mmol.h-1; P < 0.002). The maximal acid output in both groups of healthy subjects was similar. The proportion of maximal acid output to gastrin 17 achieved by cholecystokinin was similar in patients with DU (36.6%; range, 21.5%-58.2%) and H. pylori-negative healthy volunteers (28.7%; range, 5.9%-85.8%).

CONCLUSIONS

A combination of decreased sensitivity to gastrin in infected healthy volunteers and increased maximal acid secretory capacity in patients with DU underlies their different acid response to H. pylori-induced hypergastrinemia.

Does Helicobacter pylori infection contribute to gastroesophageal reflux disease?

Helicobacter pylori organisms that infect the stomach conceivably could contribute to esophageal inflammation in patients with gastroesophageal reflux disease (GERD) through any of at least three potential mechanisms: 1) by causing an increase in gastric acid secretion; 2) by spreading to infect the gastric-type columnar epithelium that occasionally can line the distal esophagus; and/or 3) by secreting noxious bacterial products into the gastric juice. Studies regarding these potential mechanisms are discussed in this report. Most investigations have found no apparent association between H. pylori infection and reflux esophagitis. Presently, infection with H. pylori does not appear to play an important role in the pathogenesis of GERD.

Effect of enprostil on omeprazole-induced hypergastrinemia and inhibition of gastric acid secretion in peptic ulcer patients

This study was performed to examine the effects of additional enprostil administration on hypergastrinemia and gastric acid suppression induced by omeprazole. Serum gastrin concentrations were measured in 10 peptic ulcer patients (six Helicobacter pylori-positive and four Helicobacter pylori-negative patients) before treatment, after two weeks of omeprazole (20 mg/day), and after two weeks of omeprazole and enprostil (50 micrograms/day). The additional acid inhibitory effect of enprostil was evaluated by 24-hr intragastric pH measurements in five healthy Helicobacter pylori-negative volunteers. After omeprazole treatment, the serum gastrin level of Helicobacter pylori-positive patients (3.5-fold of control) was markedly higher than that of Helicobacter pylori-negative patients (1.7-fold of control). Additional treatment with enprostil suppressed serum gastrin levels to 0.4-fold and 0.7-fold of omeprazole treatment levels in Helicobacter pylori-positive and Helicobacter pylori-negative patients, respectively. In healthy volunteers, median pH recorded during the nonmeal daytime interval increased significantly with additional enprostil. Thus, enprostil reduces undesirable omeprazole-induced hypergastrinemia, especially in Helicobacter pylori-positive patients, and effectively suppresses acid secretion.

Changes in serum pepsinogen, gastrin, and immunoglobulin G antibody titers in helicobacter pylori-positive gastric ulcer after eradication of infection

There are no studies of changes in immunoglobulin G (IgG) titers to Helicobacter pylori, serum pepsinogen, and gastrin in patients with H. pylori-positive gastric ulcers. We investigated the effect of therapy for H. pylori-positive gastric ulcer on IgG titers to H. pylori, serum pepsinogen I and II, and gastrin. Thirty-six patients with H. pylori-positive gastric ulcer were treated with lansorazole and antibiotics for 2 weeks. Serum pepsinogen I and II concentrations, serum gastrin, and IgG titers to H. pylori were measured before treatment and then at 4 and 12 weeks after stopping the treatment. The presence or eradication of H. pylori was determined using the rapid urease test and by histologic H. pylori staining. For 19 patients in whom H. pylori had been successfully eradicated, the pepsinogen I/II ratio increased, pepsinogen II levels decreased, and the anti-H. pylori IgG decreased compared with the results from before therapy and with those from 4 and 12 weeks after therapy. Gastrin levels decreased compared with pretreatment results and those from 4 weeks after the end of treatment. In 17 patients in whom the therapy failed to eradicate H. pylori infection, there were no sequential significant changes in the pepsinogen I/II ratio or in the levels of pepsinogen I, pepsinogen II, anti-H. pylori IgG, and gastrin. A decrease in the serum levels of the IgG antibody to H. pylori and gastrin and also an increase in the pepsinogen I/II ratio could be used as predictors for the eradication of H. pylori infection in gastric ulcer.

Helicobacter pylori inhibits the secretory activity of gastric parietal cells in patients with chronic gastritis. An ultrastructural study

BACKGROUND

Previous in vitro studies suggested that Helicobacter pylori may inhibit the acid secretion of gastric parietal cells. The aim of this study was to investigate ultrastructurally the influence of H. pylori infection on the gastric parietal cell function in vivo.

METHODS

This study comprised 28 patients with chronic gastritis. Biopsy specimens were taken from the gastric body in all cases and examined by electron microscopy. Gastric parietal cells were counted in each ultrathin section and classified into secretory and non-secretory types. The pH of the gastric juice was also measured in all patients.

RESULTS

The number of parietal cells in the secretory phase was significantly lower in H. pylori-infected (n = 16) patients than in those (n = 12) without H. pylori infection. The intragastric pH was significantly higher in patients with H. pylori-associated gastritis than in those without H. pylori infection. Parietal cells in secretory phase tended to decrease in proportion to the activity of the gastric mucosal inflammation.

CONCLUSIONS

The results of this investigation suggests that H. pylori-associated gastritis is related to a decreased secretory activity of the gastric parietal cells.

Catalase and superoxide dismutase secreted from Helicobacter pylori

BACKGROUND

Previously, we have reported that toxic oxidants produced by activated neutrophils play a pivotal role in the development of Helicobacter pylori-induced gastric mucosal damage. Microorganisms, however, are characterized by their ability to produce a variety of antioxidant enzymes. This study is designed to measure the oxygen radical scavenging enzymes, such as catalase and superoxide dismutase (SOD), and urease in the supernatant of H. pylori (NCTC11637) suspension.

MATERIALS AND METHODS

H. pylori was inoculated on a sheep blood agar plate and harvested. Bacterial suspensions (10(9) cfu/ml phosphate buffer) were washed twice and incubated at 37 degrees C for 1, 2, 12, and 24 hours or were sonicated in ice. Their supernatants were obtained by centrifugation and filtration. SOD activity was measured spectrophotometrically by the cytochrome c method. Catalase activity was assayed by the fall in absorbance at 240 nm as H2O2 is degraded. Urease activity was determined by measuring the release of ammonia using Berthelot reaction.

RESULTS

Activities of both SOD and catalase were detected in the supernatants of 1-hour microaerophilic incubation. Their activities were almost constant in 4-, 12-, and 24-hour microaerobic incubation or sonication. Urease activity was increased dramatically in proportion to the period of microaerobic incubation.

CONCLUSION

Although H. pylori possesses antioxidant as a constitutive compartment, the magnitude of its secretion was below the detectable level. It is not likely that SOD and catalase play a significant role for scavenging the oxidants from injured gastric mucosa, such as infiltrated leukocytes.

Pathophysiology of Helicobacter pylori-induced gastritis and peptic ulcer disease

Helicobacter pylori causes persistent infection and inflammation in the human stomach, yet only a small fraction of persons harboring this organism develop peptic ulcer disease. An important question is why this variation in infection outcome exists. Recent studies have demonstrated that H pylori isolates possess substantial phenotypic and genotypic diversity that may engender differential host inflammatory responses that influence clinical outcome. Further investigation in this field may help to define which H pylori-infected persons bear the highest risk for subsequent development of peptic ulcer disease, and thus enable physicians to focus eradication therapy.

Evaluation of Helicobacter pylori in reflux oesophagitis and Barrett's oesophagus

BACKGROUND

One of the major pathophysiological abnormalities in patients with gastro-oesophageal reflux disease is thought to involve transient lower oesophageal sphincter (LOS) relaxations. One component of the neural mechanism controlling the LOS appears to be a reflex are whose afferent limb originates in the gastric fundus. As inflammation is known to be associated with neural activation an investigation was made to determine whether gastric infection with H pylori is altered in prevalence or distribution in patients with reflux disease.

METHODS

Five groups of subjects referred for endoscopy-group 1: 25 controls (asymptomatic individuals with anaemia and normal endoscopy); group 2: 36 subjects with erosive oesophagitis alone (Savary-Millar grades I-III); group 3: 16 subjects with duodenal ulcer alone; group 4: 15 subjects with oesophagitis with duodenal ulcer; group 5: 16 subjects with Barrett's oesophagus. No patients were receiving acid suppressants or antibiotics. An antral biopsy specimen was taken for a rapid urease test, and two biopsy specimens were taken from the antrum, fundus, and oesophagus (inflamed and non-inflamed) for histological evidence of inflammation and presence of H pylori using a Giemsa stain.

RESULTS

Nine (36%) controls had H pylori. Patients with duodenal ulcer alone had a significantly higher incidence of colonisation by H pylori than other groups (duodenal ulcer 15 (94%); oesophagitis 13 (36%); oesophagitis+duodenal ulcer 6 (40%); Barrett's oesophagus 4 (25%)). H pylori was not more common in oesophagitis. When H pylori colonised the gastric antrum it was usually found in the gastric fundus. There was no difference in anatomical distribution of H pylori in the different patient groups. In Barrett's oesophagus H pylori was found in two of 16 in the metaplastic epithelium.

CONCLUSION

H pylori is not more common and its distribution does not differ in those with oesophagitis compared with control subjects, and is therefore unlikely to be aetiologically important in these patients. H pylori, however, can colonise Barrett's epithelium.

Circadian gastric acidity in Helicobacter pylori positive ulcer patients with and without gastric metaplasia in the duodenum

BACKGROUND

The presence of gastric metaplasia allows helicobacter pylori to colonise the duodenum and this condition is thought to be acquired as a response to acid hypersecretion. This functional disorder, however, is present only in a subgroup of duodenal ulcer patients and, in addition, surface gastric metaplasia has been frequently found in the proximal duodenum of normal subjects and patients with non-ulcer dyspepsia, who cannot be certainly considered as acid hypersecretors.

AIMS

To clarify the role of acid in inducing gastric type epithelium in the duodenum. This study aimed at assessing whether the pattern of circadian gastric acidity differs between H pylori positive duodenal ulcer patients with and without duodenal gastric metaplasia.

PATIENTS

Seventy one patients with duodenal ulcer confirmed by endoscopy and who were found to be positive for H pylori infection by histology on antrum biopsy specimens were enrolled into this study.

METHODS

Gastric type epithelium in the duodenum was found in 49 of 71 ulcer patients (69%). Continuous 24 hour gastric pH metry was performed in 50 healthy subjects and in the two subgroups of duodenal ulcer patients with and without gastric metaplasia in the duodenum. Gastric acidity was calculated for 24 hours (1700-1659), night (2000-0759) and day-time (0800-1959).

RESULTS

Ulcer patients without gastric metaplasia showed a significantly higher gastric acidity (p < 0.001) than controls for every time interval considered, while the ulcer subgroup with gastric metaplasia was more acid than healthy subjects (p < 0.001) during the whole 24 hour period and the daytime. There was no difference between the two subgroups of duodenal ulcer patients with and without gastric metaplasia during the various time segments analysed.

CONCLUSION

The findings confirm that the circadian gastric acidity of duodenal ulcer patients is higher than that of controls. As there is no difference in gastric pH between duodenal ulcer patients with and without gastric metaplasia, gastric hyperacidity is not specific to patients with duodenal gastric metaplasia. It is probable that this histological change is a non-specific response to mucosal injury resulting from various factors and not exclusively to acid.

Does Helicobacter pylori-induced gastritis enhance food-stimulated insulin release?

The fact that H. pylori gastritis results in an increased secretion of basal and meal-stimulated gastrin, which is also a physiologic amplifier of insulin release directed us to investigate whether H. pylori gastritis may lead to an enhancement of nutrient-stimulated insulin secretion. For this purpose, we have investigated the insulin responses to both oral glucose and a mixed meal in 15 patients with H. pylori gastritis before and one month after the eradication therapy and also in 15 H. pylori-negative control subjects. The areas under the curve (AUC) for serum insulin following both oral glucose and a mixed meal in the patients with H. pylori gastritis before the eradication were significantly (P < 0.05) higher than those in the H. pylori-negative controls. After the eradication of H. pylori, the AUC for serum insulin following oral glucose and mixed meal decreased by 9.4% and 13.1%, respectively (P < 0.001 in both), and serum basal and meal-stimulated gastrin levels decreased significantly (P < 0.001). These results suggest that H. pylori gastritis enhances glucose and meal-stimulated insulin release probably by increasing gastrin secretion.

High acid secretion may protect the gastric mucosa from injury caused by ammonia produced by Helicobacter pylori in duodenal ulcer patients

The aim of the present study was to investigate the mechanism by which gastric atrophy does not tend to occur in patients with duodenal ulcer despite frequent Helicobacter pylori infection. This investigation was performed in 60 patients with duodenal ulcer and 63 age-matched gastritis patients. Endoscopic findings in the antrum and corpus were classified as normal, atrophic and superficial changes. Biopsy specimens were taken from the antrum and corpus. Ninety per cent of patients with duodenal ulcer and 63.5% of patients with gastritis had H. pylori infection (P < 0.01). The incidence of normal findings in duodenal patients was 30% in antral regions and 50% in the corpus (P < 0.05). Atrophic change was observed in 21.7% of patients in the antrum and 3.3% of patients in the corpus (P < 0.01). The grade of inflammation in duodenal ulcer specimens was significantly higher in the antrum than in the corpus (P < 0.01). H. pylori density was significantly higher in the antrum than in the corpus in ulcer patients (P < 0.01). No significant difference in endoscopic findings, H. pylori density or the grade of inflammation was found between the antrum and corpus in patients with gastritis. The mean intragastric ammonia concentration was 10.3 mg/dL in duodenal ulcer patients and 6.2 mg/dL in gastritis patients (P < 0.01). The mean pH was 3.5 and 4.6 in ulcer and gastritis specimens, respectively (P < 0.01). Our data suggest that gastric mucosa injury is less frequently associated with duodenal ulcers than with gastritis due to the low H. pylori density in the corpus and to the higher acid output that neutralizes the ammonia produced by H. pylori.

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.

Gastric emptying and Helicobacter pylori infection in duodenal ulcer disease

The pathogenetic link between Helicobacter pylori gastritis and duodenal ulcer is still unknown. Fast gastric emptying of liquids might be important in the pathogenesis of gastric metaplasia of the duodenum and duodenal ulcer through an increased exposure of the duodenum to gastric acid. In H. pylori-infected subjects, an abnormal gastric emptying could affect urea breath test results and correlate with histological gastritis. This study was performed to evaluate the gastric emptying of liquids in duodenal ulcer patients with H. pylori infection and the possible relation between the bacterial load, gastric emptying, and urea breath test results. Seventeen duodenal ulcer patients with H. pylori gastritis and 15 healthy volunteers were studied by a [14C]octanoic acid and [13C]urea breath test to evaluate gastric emptying rate and H. pylori status simultaneously. Endoscopy with antral biopsies were performed in all duodenal ulcer patients. Duodenal ulcer patients with H. pylori infection have a normal liquid gastric emptying that is unrelated with histological severity of gastritis. The urea breath test results and the gastric emptying parameters do not correlate with histology. A significant correlation between the gastric emptying and the urea hydrolysis rate is found. It is concluded that H. pylori infection and duodenal ulcer disease is not associated with abnormally fast liquid gastric emptying, and this finding should be taken into account when a casual link between H. pylori infection and duodenal ulcer disease is searched for. The correlation between gastric emptying and urea hydrolysis rate explains why no conclusions on intragastric bacterial load can be drawn from the urea breath test results.

Prolonged hypergastrinemia does not increase the frequency of colonic neoplasia in patients with Zollinger-Ellison syndrome

Whereas considerable experimental evidence suggests chronic hypergastrinemia can increase the occurrence of colonic neoplasia, the risks in man remain unclear. Zollinger-Ellison syndrome (ZES) is associated with marked plasma elevation of all forms of gastrin and, because of its prolonged course, has been shown to be an excellent model disease to study the effects of chronic hypergastrinemia in man. To determine whether profound chronic hypergastrinemia affects the occurrence of colonic dysplasia and neoplasia, 97 consecutive patients with ZES were studied. All patients underwent colonoscopic examination to the cecum, and the location, size, and type of polyps/tumors were determined. The patients had a mean fasting gastrin level 31 times above normal and a mean disease duration of 10 years; 17/97 (18%) had adenomatous polyps, 67/97 (69%) no adenomatous polyps, and 2/97 (2%) had colonoscopy and/or autopsy studies fo asymptomatic controls. Stratification by age or gender, presence of MEN-I, tumor extent, and duration of degree of hypergastrinemia did not increase prevalence. This study shows that despite prolonged, profound hypergastrinemia, no increased rate of colonic neoplasia (polyps or cancer) was noted. These data suggest that the development of hypergastrinemia secondary to continuous use of H+,K+-ATPase inhibitors for as long as 10 years is unlikely to cause an increased risk of developing colonic neoplasia in man.

Helicobacter pylori and disturbance of gastric function associated with duodenal ulcer disease and gastric cancer

Helicobacter pylori is now recognized as the major acquired factor in the pathogenesis of duodenal ulcer disease (DU). There is also an association between H. pylori infection and the subsequent development of gastric cancer. The mechanisms by which such infection predisposes the host to these diseases are incompletely understood, but disorders induced by the bacterium in gastric function play a pivotal role. In most patients, H. pylori infection stimulates acid secretion, leading to a predisposition to DU development. However, in some patients, the infection is associated with a significant decrease in acid secretion, a predisposition to gastric cancer. These divergent effects of H. pylori on gastric acid secretion explain the early conflicting reports on changes in acid secretion associated with the infection. The reason why H. pylori infection produces divergent effects on gastric acid secretion is unclear, but may be related to differences in bacterial strains or genetic, dietary or other environmental factors.

Enhanced levels of chemiluminescence and platelet activating factor in urease-positive gastric ulcers

Helicobacter pylori are believed to play an important role in the formation of gastric ulcer in a syndrome characterized by a high urease activity. On the other hand, the production of oxygen radicals and platelet activating factor (PAF) is enhanced in gastric ulcers. The present study is designed to investigate the relationship between the different aspects of gastric mucosal injury, urease activity, oxygen radical production, and PAF content in gastric specimens. Biopsy specimens taken from 35 gastric ulcer patients were studied. Urease activity was detected by a rapid urease test (CLO). Oxygen radical production was measured as a value of luminol-dependent chemiluminescence (ChL) and PAF content was determined by radioimmunoassay in the biopsy samples. The CLO-positive rate was significantly higher in the gastric ulcer group in comparison with that in controls. ChL values and PAF content were significantly increased in gastric ulcers, especially in CLO-positive specimens. The CLO-positive rate, ChL values, and PAF content were also found to be increased at a distant site beyond the ulcer lesions. During the course of macroscopic ulcer healing of CLO-positive cases, the CLO positive level and the ChL values were not significantly decreased, although PAF content was significantly lower. Enhanced oxygen radical and PAF production were observed not only in the ulcer region but also at a distant site from the ulcer in the urease-positive gastric mucosa. The persistent enhancement of ChL values during the healing stage of urease-positive gastric ulcers suggests its involvement in the recurrence of gastric ulcers.

Serum gastrin and mucosal somatostatin in Helicobacter pylori-associated gastritis

AIMS

The aims were to study gastrin concentrations and gastric mucosal somatostatin and gastrin concentrations in relation to the extent of gastritis in Helicobacter infection.

METHODS

We measured basal serum gastrin concentrations in antral mucosal biopsy specimens and somatostatin concentrations in corpus biopsy specimens in 88 consecutive dyspeptic subjects undergoing endoscopy. These subjects were divided into three categories on the basis of histology, serology, and culture: H. pylori-positive pangastritis, H. pylori positive antral gastritis with normal body histology, and H. pylori-negative controls. Statistical evaluation was done with the Wilcoxon rank sum test.

RESULTS

Basal serum gastrin concentrations were significantly increased only in subjects with pangastritis and not in those with antral gastritis only, as compared with controls (mean +/- SEM: 72 +/- 7, 46 +/- 10, and 42 +/- 7 ng/l, respectively). Subjects with pangastritis or antral gastritis had significantly lower antral somatostatin concentrations than controls (mean +/- SEM: 0.80 +/- 0.07, 1.03 +/- 0.15, and 2.40 +/- 0.31 micrograms/g(protein), respectively). We also found significantly lower antral gastritis only as compared with controls (mean +/- SEM: 62 +/- 13, 78 +/- 16, and 165 +/- 25 micrograms/g(protein), respectively). In subjects with pangastritis a significantly lower concentration of somatostatin was found in the corpus biopsy specimens than in those with antral gastritis only and controls.

CONCLUSIONS

These results suggest that hypergastrinemia in H. pylori gastritis is not caused by antral gastritis and antral somatostatin deficiency alone but that corpus inflammation plays a key role in the origin of hypergastrinemia. Furthermore, in patients with pangastritis a corpus mucosal somatostatin deficiency was found.

Eradication of Helicobacter pylori infection in patients with non-ulcer dyspepsia. Effects on basal and bombesin-stimulated serum gastrin and gastric acid secretion

BACKGROUND

This study evaluates the effect of eradicating Helicobacter pylori on basal and bombesin-stimulated gastric acid secretion and serum gastrin in non-ulcer dyspepsia.

METHODS

Before and 1 month after an attempt to eradicate H. pylori basal and bombesin-stimulated gastric acid outputs were measured in 23 patients. H. pylori was eradicated in 15 patients (group A) but not in the other 8 (group B). Incremental gastric acid output was calculated by subtracting basal from bombesin-stimulated values.

RESULTS

Basal acid output increased significantly (p = 0.01) after therapy in group A (delta 1.6 +/- 0.6 mmol/h) but not in group B (delta 0.2 +/- 0.5 mmol/h). Incremental gastric acid output decreased distinctly (delta-3.9 +/- 1.4 mmol/h) after therapy in group A (p = 0.02) but not in group B (delta-2.2 +/- 1.7 mmol/h). Basal serum gastrin decreased significantly (p < 0.005) after therapy in group A (delta-9 +/- 4 pM) but not in group B (delta-1 +/- 2 pM). Integrated serum gastrin responses to bombesin decreased markedly (p < 0.001) after therapy in group A (delta-5.0 +/- 1.6 nM*60 min) but slightly in group B (delta-0.9 +/- 1.3 nM*60 min) (p < 0.05).

CONCLUSIONS

In patients with non-ulcer dyspepsia basal serum gastrin concentrations decrease but basal gastric acid outputs increase after eradication of H. pylori. Bombesin-induced increments in gastric acid output, however, decrease in parallel with gastrin release.

Behaviour of acid secretion, gastrin release, serum pepsinogen I, and gastric emptying of liquids over six months from eradication of helicobacter pylori in duodenal ulcer patients. A controlled study

The behaviour of basal and stimulated acid secretion, gastrin release, serum pepsinogen I, and gastric emptying of liquids was studied in 19 consecutive patients with Helicobacter pylori positive duodenal ulcer, over a follow up period of six months. Eleven patients were studied before and at three and six months after eradication with lansoprazole plus amoxicillin and tinidazole (case group), whereas the remainder, with persistent H pylori infection, were studied before and after three and six months from ulcer healing, thus constituting the control group. In the case group, three months after eradication, fasting serum pepsinogen I fell from (mean (SEM)) 91.9 (6.9) (pretreatment) to 72.2 (5.1) ng/l and the integrated gastrin response to a meal reduced from 11,470 (1174) (pretreatment) to 8130 (608) pg/ml/h (p < 0.05). Fasting serum gastrin concentrations and maximal acid output reduced significantly only six months after eradication. In contrast, no significant change of any of these measurements was seen in the control group either at three or six months from healing compared with the pretreatment values. Gastric emptying of liquids did not change over the entire period of follow up in both study groups. In conclusion, eradication of H pylori in duodenal ulcer patients is accompanied by a rapid fall in serum pepsinogen I and plasma gastrin concentrations, whereas a slight but significant reduction of maximal acid secretion takes place later on. In contrast, gastric emptying of liquids does not seem to be influenced by H pylori status.

Helicobacter pylori infection is associated with low antral somatostatin content in young adults. Implications for the pathogenesis of hypergastrinemia

BACKGROUND

Recent studies on the role of Helicobacter pylori in the pathogenesis of duodenal ulcers have focused on the mechanism by which H. pylori infections cause exaggerated gastrin release.

METHODS

We determined meal-stimulated serum gastrin concentrations and antral somatostatin content in 24 asymptomatic volunteers (6 H. pylori-infected, 18 H. pylori-uninfected). Somatostatin content was determined by radioimmunoassay in biopsy specimens obtained from the antrum.

RESULTS

Fasting and integrated 2-h gastrin concentrations were significantly higher in H. pylori-positive volunteers than in H. pylori-negative volunteers (fasting, 111 +/- 16.3 pmol/l versus 53.4 +/- 3.5 pmol/l; p < 0.05; integrated 2-h, 267 +/- 41.2 pmol/l versus 70.1 +/- 2.1 pmol/l; p < 0.01). Antral somatostatin content was 0.764 +/- 0.173 ng/mg and 2.931 +/- 0.414 ng/mg in H. pylori-positive and -negative volunteers, respectively (p < 0.01).

CONCLUSIONS

Low antral somatostatin content may cause hypergastrinemia in asymptomatic healthy volunteers, and H. pylori may contribute to the pathogenesis of duodenal ulcer, through this mechanism.

Diagnosis of gastric adenocarcinoma using a scoring system: combined assay of serological markers of Helicobacter pylori infection, pepsinogen I and gastrin

This study was carried out to develop a scoring system for the diagnosis of gastric adenocarcinoma (GAC). A total of 686 subjects, 150 patients with GAC, 182 with gastric ulcer, 127 with duodenal ulcer, and 227 subjects with negative findings, were enrolled. Analysis of the likelihood ratio (LR) showed that patients with advanced age, ulcer in the stomach, low serum levels of pepsinogen I (PGI), low PGI x gastrin values, and low PGI/gastrin ratio were likely to have GAC. Of these indicators, the serum PGI level had the greatest weight, with a LR of 7.59 for the group with a level < 30 ng/ml. A scoring system combining serum PGI level, Helicobacter pylori seropositivity, and gastric ulcer status was derived, using a logistic regression model. This scoring system was found to be better than any one-parameter criterion for diagnosing GAC after evaluation by the area under the receiver operating characteristic curve (0.84; 95% confidence interval, 0.81-0.88) or by specificity-fixed sensitivity (sensitivity 0.82 at specificity 0.72, sensitivity 0.87 at specificity 0.66, sensitivity 0.96 at specificity 0.44). This scoring system may be potentially useful as a new model for the noninvasive diagnosis of GAC in the future.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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