Distribution of atrophy in Helicobacter pylori-infected subjects taking proton pump inhibitors

Houston Consensus Conference on Testing for Helicobacter pylori Infection in the United States

Despite guidelines for detection and treatment of Helicobacter pylori infection, recommendations to test patients before and after therapy are commonly not followed in the United States. At the Houston Consensus Conference, 11 experts on management of adult and pediatric patients with H pylori, from different geographic regions of the United States, met to discuss key factors in diagnosis of H pylori infection, including identification of appropriate patients for testing, effects of antibiotic susceptibility on testing and treatment, appropriate methods for confirmation of infection and eradication, and relevant health system considerations. The experts divided into groups that used a modified Delphi panel approach to assess appropriate patients for testing, testing for antibiotic susceptibility and treatment, and test methods and confirmation of eradication. The quality of evidence and strength of recommendations were evaluated using the GRADE system. The results of the individual workshops were presented for a final consensus vote by all panel members. After the Expert Consensus Development meeting, the conclusions were validated by a separate panel of gastroenterologists, who assessed their level of agreement with each of the 29 statements developed at the Expert Consensus Development. The final recommendations are provided, on the basis of the best available evidence, and provide consensus statements with supporting literature to implement testing for H pylori infection at health care systems across the United States.

Effect of long-term proton pump inhibitor administration on gastric mucosal atrophy: A meta-analysis

BACKGROUND/AIMS

Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related gastrointestinal diseases. Recently, some studies have reported that PPIs can alter the gastric mucosal architecture; however, the relationship remains controversial. This meta-analysis study was designed to quantify the association between long-term PPI administration and gastric atrophy.

MATERIALS AND METHODS

A PubMed search was conducted to identify studies using the keywords proton pump inhibitors or PPI and gastric atrophy or atrophic gastritis; the timeframe of publication searched was up to May 2016. Heterogeneity among studies was tested with the Q test; odds ratios (OR) and 95% confidence intervals (CI) were calculated. P values were calculated by I2 tests and regarded as statistically significant when <0.05.

RESULTS

We identified 13 studies that included 1465 patients under long-term PPI therapy and 1603 controls, with a total gastric atrophy rate of 14.50%. There was a higher presence of gastric atrophy (15.84%; statistically significant) in PPI group compared to the control group (13.29%) (OR: 1.55, 95% CI: 1.00-2.41).

CONCLUSIONS

The pooled data suggest that long-term PPI use is associated with increased rates of gastric atrophy. Large-scale multicenter studies should be conducted to further investigate the relationship between acid suppressants and precancerous diseases.

Eradication of Helicobacter pylori Infection

Helicobacter pylori infects about 50 % of the world's population, causing at a minimum chronic gastritis. A subset of infected patients will ultimately develop gastric or duodenal ulcer disease, gastric adenocarcinoma, or MALT (mucosa-associated lymphoid tissue) lymphoma. Eradication of H. pylori requires complex regimens that include acid suppression and multiple antibiotics. The efficacy of treatment using what were once considered standard regimens have declined in recent years, mainly due to widespread development of antibiotic resistance. Addition of bismuth to standard triple therapy regimens, use of alternate antibiotics, or development of alternative regimens using known therapies in novel combinations have improved treatment efficacy in specific populations, but overall success of eradication remains less than ideal. Novel regimens under investigation either in vivo or in vitro, involving increased acid suppression ideally with fewer antibiotics or development of non-antibiotic treatment targets, show promise for future therapy.

Value of the "Test & Treat" Strategy for Uninvestigated Dyspepsia at Low Prevalence Rates of Helicobacter pylori in the Population

BACKGROUND AND AIM

In populations with a low prevalence rate of Helicobacter pylori (H. pylori) infection from Western countries, guidelines for the management of uninvestigated dyspepsia generally recommend that the "test and treat" strategy should be avoided in favor of empiric proton-pump inhibitor therapy in younger patients (on average < 50 years of age) without alarm symptoms and signs. The prevalence of H. pylori infection has fallen from about 30% to about 10% in Sweden and other countries. We aimed to explore whether the rationale for test and treat is relevant in contemporary clinical practice.

MATERIALS AND METHODS

In settings with an infection rate in the adult population of 30% and 10%, we modeled the positive and negative predictive values for indirect (nonendoscopy) tests on current H. pylori infection with a presumed sensitivity and specificity of 95%. We then calculated the difference in false-negative and false-positive test outcome, and eradication prescription rates in the two scenarios.

RESULTS

While the positive predictive value for the test decreased from 0.89 to 0.68 when the prevalence of H. pylori fell from 30% to 10%, there were only 1% more false-negative tests and 1% less false-positive tests. The eradication prescription rate would decrease by 18% with a 10% prevalence rate.

CONCLUSION

The recommendation to stop applying "test and treat" at lower prevalence rates of H. pylori should be reconsidered. The test and treat strategy is the preferred approach for most patients who present with dyspepsia.

Systematic review: the effects of long-term proton pump inhibitor use on serum gastrin levels and gastric histology

BACKGROUND

Proton pump inhibitors (PPIs) have a well-established safety profile. However, concerns have been raised about a potential relationship between PPI-induced hypergastrinaemia and the development of enterochromaffin-like (ECL) cell hyperplasia, neuroendocrine tumours and gastric cancer during long-term therapy.

AIM

To review the effects of long-term PPI use on serum gastrin levels and gastric histopathology.

METHODS

A systematic literature search was conducted in PubMed on 21 April 2015 to identify studies reporting the effects of long-term (defined as >3 years) PPI use on gastrin levels and gastric histopathology.

RESULTS

A total of 16 studies (1920 patients) met the inclusion criteria. During long-term PPI therapy, mean gastrin levels rose to one to three times the upper limit of the normal range (~100 pg/mL), and an increased prevalence of ECL cell hyperplasia was observed (+7.8-52.0%). Helicobacter pylori-positive patients had a significantly increased risk of developing ECL linear/micronodular hyperplasia compared with H. pylori-negative patients [OR: 2.45 (95% CI: 1.47-4.10), P = 0.0006]; however, no evidence of neoplastic changes was found. The risk of corpus atrophy was markedly higher in H. pylori-positive patients than in H. pylori-negative patients [OR: 11.45 (95% CI: 6.25-20.99), P < 0.00001]. Not a single case of gastric adenocarcinoma was found.

CONCLUSIONS

Long-term PPI therapy induced moderate hypergastrinaemia in most patients and an increased prevalence of ECL cell hyperplasia. H. pylori-positive patients receiving long-term PPI therapy were exposed to a higher risk of corpus atrophy than H. pylori-negative patients. No neuroendocrine tumours or gastric cancers were found.

Gastric exocrine and endocrine cell morphology under prolonged acid inhibition therapy: results of a 5-year follow-up in the LOTUS trial

BACKGROUND

Sustained acid inhibition with PPI stimulates gastrin secretion, exerting a proliferative drive on enterochromaffin-like cells (ECL cells) of the oxyntic mucosa. It may also accelerate development of gastric gland atrophy in Helicobacter pylori-infected individuals.

AIMS

To evaluate gastric exocrine and endocrine cell changes in GERD patients randomised to laparoscopic antireflux surgery (LARS, n = 288) or long-term (5 years) esomeprazole (ESO) treatment (n = 266).

METHODS

Antral and corpus biopsies were taken at endoscopy and serum gastrin and chromogranin A levels were assayed, at baseline and after 1, 3 and 5 years' therapy.

RESULTS

Biopsies were available at each time point for 158 LARS patients and 180 ESO patients. In H. pylori-infected subjects, antral mucosal inflammation and activity improved significantly (P < 0.001) and stabilised after 3 years on esomeprazole while no change in inflammation was observed after LARS. Oxyntic mucosal inflammation and activity remained stable on esomeprazole but decreased slightly over time after LARS. Neither intestinal metaplasia nor atrophy developed in the oxyntic mucosa. ECL cell density increased significantly after ESO (P < 0.001), corresponding with an increase in circulating gastrin and chromogranin A. After LARS, there was a significant decrease in ECL cell density (P < 0.05), accompanied by a marginal decrease in gastrin and chromogranin.

CONCLUSIONS

Antral gastritis improved in H. pylori-infected GERD patients after 5 years on esomeprazole, with little change in laparoscopic antireflux surgery patients, who acted as a control. Despite a continued proliferative drive on enterochromaffin-like cells during esomeprazole treatment, no dysplastic or neoplastic lesions were found and no safety concerns were raised. NCT 00251927.

Long-term proton pump inhibitor use and gastrointestinal cancer

Proton pump inhibitors profoundly affect the stomach and have been associated with carcinoid tumors in female rats. There is now sufficient experience with this class of drugs to allow reasonable estimation of their safety in terms of cancer development in humans. Long-term use of proton pump inhibitors is associated with an increase in gastric inflammation and development of atrophy among those with active Helicobacter pylori infections. The actual risk is unknown but is clearly low. However, it can be markedly reduced or eliminated by H. pylori eradication. It is thus recommended that patients being considered for long-term proton pump inhibitor therapy should be tested for H. pylori infection and, if present, this pathogen should be eradicated. Oxyntic cell hyperplasia, glandular dilatations, and fundic gland polyps may develop in patients not infected with H. pylori, but these changes are believed to be reversible and without significant cancer risk.

The risk of gastric cancer in patients with duodenal and gastric ulcer: research progresses and clinical implications

INTRODUCTION

Although controversial, clinicians generally consider patients who present with gastric ulcer to have an increased risk of gastric cancer, while the risk for patients with duodenal ulcer is reduced in comparison with that of the general population. Infection with Helicobacter pylori and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are the major causes for peptic ulcers, but their roles in relation to the risk of gastric cancer in patients with peptic ulcer may be different.

METHODS AND RESULTS

This article reviewed existing literature to assess our understanding of the risk of gastric cancer in patients with gastric and duodenal ulcers more than 25 years after the discovery of H. pylori and also examined whether gastric ulcers induced by NSAID carry a lower risk of gastric cancer as compared to those induced by H. pylori infection or other causes.

Inflammation, atrophy, and gastric cancer

The association between chronic inflammation and cancer is now well established. This association has recently received renewed interest with the recognition that microbial pathogens can be responsible for the chronic inflammation observed in many cancers, particularly those originating in the gastrointestinal system. A prime example is Helicobacter pylori, which infects 50% of the world's population and is now known to be responsible for inducing chronic gastric inflammation that progresses to atrophy, metaplasia, dysplasia, and gastric cancer. This Review provides an overview of recent progress in elucidating the bacterial properties responsible for colonization of the stomach, persistence in the stomach, and triggering of inflammation, as well as the host factors that have a role in determining whether gastritis progresses to gastric cancer. We also discuss how the increased understanding of the relationship between inflammation and gastric cancer still leaves many questions unanswered regarding recommendations for prevention and treatment.

Progression of atrophic gastritis and intestinal metaplasia drives Helicobacter pylori out of the gastric mucosa

This study was performed to evaluate the implication of anti-H. pylori IgG positivity when CLOtest, histological test, and culture in the antrum and body are all negative, and to find out the specific disease category that is more affected by the hostile relationship of atrophic gastritis and intestinal metaplasia (IM) with H. pylori. Four hundred thirty-six patients (84 controls, 69 with duodenal ulcer, 96 with benign gastric ulcer, 43 with dysplasia, 144 with gastric cancer), who had not received any eradication therapy, were divided into three groups according to H. pylori test: CLOtest or histological H. pylori-positive group (group A; 294 cases), only anti-H. pylori IgG-positive group (group B; 62 cases), and anti-H. pylori IgG-negative group (group C; 80 cases). The grade of neutrophil and monocyte infiltration, atrophic gastritis, and IM was compared according to the updated Sydney system classification. Neutrophil and monocyte infiltrations were significantly severe in the group A. In contrast, the grade of atrophic gastritis and IM in the antrum was significantly higher in group B than the other two groups, A or C. When patients were divided according to the disease outcome in each group, the grade of IM in the body was statistically higher only in the patients with cancer or dysplasia in group B. These results suggest that anti-H. pylori IgG positivity with all negative invasive H. pylori tests represents past infection with H. pylori rather than a false negative, especially in the case of dysplasia and gastric cancer.

Changes of gastric mucosal architecture during long-term omeprazole therapy: results of a randomized clinical trial

BACKGROUND

The impact of long-term acid suppression on the gastric mucosa remains controversial.

AIM

To report further observations on an established cohort of patients with gastro-oesophageal reflux disease, after 7 years of follow-up.

METHODS

Of the original cohort randomized to either antireflux surgery or omeprazole, 117 and 98 patients remained in the medical and surgical arms, respectively. Gastric biopsies were taken at baseline and throughout the study.

RESULTS

Fifty-three antireflux surgery and 39 omeprazole-treated patients had Helicobacter pylori infection at randomization. Eighty-three omeprazole-treated and 60 antireflux surgery patients remained H. pylori negative over the 7 years, and no change was observed in mucosal morphology except for a change in endocrine cell population (linear and diffuse hyperplasia, P = 0.03). During the 7-year study many patients, who were initially H. pylori infected, had the infection eradicated leaving only 13 omeprazole and 12 antireflux surgery patients still infected. In these patients, omeprazole induced a deterioration of the mucosal inflammation scores (P = 0.01) with a numerical increase of glandular atrophy.

CONCLUSIONS

Long-term omeprazole therapy does not alter the exocrine oxyntic mucosal morphology in H. pylori-negative patients, but mucosal endocrine cells appear to be under proliferative stimulation; in H. pylori-positive patients there are changes in mucosal inflammation and atrophy.

Long-term acid suppression by omeprazole in gastro-oesophageal reflux disease patients does not lead to anti-gastric autoantibody production

BACKGROUND

Helicobacter pylori-associated atrophy of the gastric corpus is associated with the presence of anti-canalicular autoantibodies. Also, long-term profound acid suppression in H. pylori-infected subjects may cause atrophic corpus gastritis.

AIM

To investigate whether long-term acid suppression by omeprazole leads to antigastric autoantibodies.

METHODS

Fifty patients, of which 34 H. pylori-positive on entry of the study, were treated with omeprazole (20-40 mg once daily) for reflux oesophagitis, and were evaluated for anti-gastric autoantibody responses by immunohistochemistry before and after treatment. H. pylori was not eradicated and patients were followed for an average of 6.6 years (range 3-14.1 years). In addition to immunohistochemistry, anti-H(+), K(+)-ATPase reactivity was assessed by Western blot in paired sera of 41 patients (26 H. pylori-positive and 15 uninfected) and results are critically evaluated.

RESULTS

In immunohistochemistry, all patients were negative for anti-canalicular autoantibodies when omeprazole therapy started, except for two patients with corpus-predominant gastritis in the presence of H. pylori. One patient, who was H. pylori-negative, newly developed an anti-canalicular antibody response during therapy.

CONCLUSIONS

Our results indicate that, as compared with non-infected patients, long-term profound acid suppression therapy in H. pylori-infected gastro-oesophageal reflux disease patients does not increase or accelerate gastric autoimmunity.

A negative Helicobacter pylori serology test is more reliable for exclusion of premalignant gastric conditions than a negative test for current H. pylori infection: a report on histology and H. pylori detection in the general adult population

OBJECTIVE

Corpus-dominant gastritis, gastric mucosal atrophy and intestinal metaplasia (IM) associated with Helicobacter pylori infection are all known potential risk markers for the development of gastric cancer. As the accuracy for finding cases at risk in the general population is unknown, we aimed to determine the prevalence of current and/or past H. pylori infection and associated gastric mucosal findings by means of histological survey of a random adult population.

MATERIAL AND METHODS

A random Swedish sample (n = 3000, age 20-81 years) was surveyed using a validated gastrointestinal symptom questionnaire with 74% response rate. One-third of the responders were selected at random for esophago-gastro-duodenoscopy with biopsies and H. pylori serology.

RESULTS

Of those endoscoped (n = 1000, mean age 53.5, 51% women), 43.0% were H. pylori+ by serology (seropositive), 33.9% had signs of current infection on either histology or culture (gold standard+), and 9.3% were seropositive, but gold standard negative. Corpus atrophy was found in 10% and IM in 13% when gold standard positive, and in a significantly higher number (17% and 21%, respectively) of those with only a serological sign of past infection. Among those who were seronegative, values were 1% and 2%, respectively. Corpus-dominant gastritis was found in 4.1%, all seropositive.

CONCLUSION

One-third had an ongoing H. pylori infection, and a further 10% had signs of past infection. Corpus-dominant gastritis was found mostly among the former, while detection of those with corpus atrophy and IM also required a test for past infection. Seronegativity almost excludes precancerous conditions in a screening situation.

Acid-adaptive genes of Helicobacter pylori

Helicobacter pylori is the only neutralophile that has been able to colonize the human stomach by using a variety of acid-adaptive mechanisms. One of the adaptive mechanisms is increased buffering due to expression of an acid-activated inner membrane urea channel, UreI, and a neutral pH-optimum intrabacterial urease. To delineate other possible adaptive mechanisms, changes in gene expression in response to acid exposure were examined using genomic microarrays of H. pylori exposed to different levels of external pH (7.4, 6.2, 5.5, and 4.5) for 30 min in the absence and presence of 5 mM urea. Gene expression was correlated with intrabacterial pH measured using 2',7'-bis-(2-carboxyethyl)-5-carboxyfluorescein and compared to that observed with exposure to 42 degrees C for 30 min. Microarrays containing the 1,534 open reading frames of H. pylori strain 26695 were hybridized with cDNAs from control (pH 7.4; labeled with Cy3) and acidic (labeled with Cy5) conditions. The intrabacterial pH was 8.1 at pH 7.4, fell to 5.3 at pH 4.5, and rose to 6.2 with urea. About 200 genes were up-regulated and approximately 100 genes were down-regulated at pH 4.5 in the absence of urea, and about half that number changed in the presence of urea. These genes included pH-homeostatic, transcriptional regulatory, motility, cell envelope, and pathogenicity genes. The up-regulation of some pH-homeostatic genes was confirmed by real-time PCR. There was little overlap with the genes induced by temperature stress. These results suggest that H. pylori has evolved multifaceted acid-adaptive mechanisms enabling it to colonize the stomach that may be novel targets for eliminating infection.

Expression of UreI is required for intragastric transit and colonization of gerbil gastric mucosa by Helicobacter pylori

Helicobacter pylori colonizes the antral mucosa of the human stomach. There is a controversy as to whether the microorganism is exposed to acidity in its ecological niche. In vitro, the microorganism requires urease for gastric colonization and survival at pH < 4.0. UreI encodes an acid activated urea channel enabling urea access to intrabacterial urease at acidic pH. UreI is also necessary for survival at pH < 4.0. However, the role of UreI for both intragastric transit and colonization of the epithelial gastric mucosa has never been analyzed in detail. We therefore infected gerbils, whose intragastric pH and response to infection resemble those of man, with H. pylori G1.1 wild type bacteria and their corresponding isogenic ureI mutants. Inhibitors of gastric acid secretion and colonization were used for manipulation of gastric pH. Gastric colonization was determined by urease assay and PCR. Gastric pH was measured with pH electrodes. Whereas H. pylori wild type or ureI complemented ureI knockout bacteria colonized the antrum, ureI deletion mutants were unable to colonize. However, continuous inhibition of acid secretion resulted in gastric colonization by the ureI mutants, as also observed with the wild type strain. Restoration of acid secretion resulted in eradication of ureI mutants but not wild type bacteria. The data show that ureI is essential for both gastric transit after inoculation and mucosal colonization in the untreated stomach. The eradication of ureI mutants following restoration of acid secretion suggests that the organism is exposed to pH < 4.0 at the surface of the antral mucosa and that UreI provides a target for specific monotherapy of H. pylori infections.

Chronic inactive gastritis and coccoid Helicobacter pylori in patients treated for gastroesophageal reflux disease or with H pylori eradication therapy

Gastric biopsy specimens from 105 consecutive adults with persistent dyspepsia who did not have changes due to esophageal reflux disease changes or gastric or duodenal ulcers at endoscopy were scored using the updated Sydney gastritis classification system. The medication history of proton pump inhibitors (PPIs) or Helicobacter pylori eradication therapy during the month before endoscopy was retrieved. Of the patients, 72 (68.6%) had chronic inactive gastritis, and 7 (6.7%) had antral-predominant, chronic mild active gastritis. H pylori infection was present in 36 patients (34.3%), of whom 29 had chronic inactive gastritis. Forty-six patients (43.8%) had a positive medication history, including 40 (56%) of 72 with chronic inactive gastritis. The most common morphologic feature associated with H pylori infection was moderate chronic inactive gastritis, which was found most often in patients who had received recent PPIs or H pylori eradication therapy. Pathologists should be aware of the extensive use of these medications, their association with chronic inactive gastritis, and rare H pylori thatfrequently are coccoid shaped. Modified Giemsa stain may not be the optimal method to detect H pylori in this group of patients.

Ammonia-induced apoptosis is accelerated at higher pH in gastric surface mucous cells

Gastric luminal ammonia produced by Helicobacter pylori has been shown to cause gastric mucosal injury. This study was conducted to examine the mechanisms by which gastric luminal ammonia causes apoptosis of gastric epithelial cells. Monolayers of GSM06 cells, developed from murine gastric surface mucous cells, were cultured in the absence or presence of 10-30 mM NH(4)Cl at ambient pH of 5.0, 6.0, and 7.0. In the presence of luminal NH(4)Cl, GSM06 cells showed 1) cell shrinkage and nuclear chromatin condensation, 2) DNA fragmentation into oligonucleosomes, 3) leakage of cytochrome c into cytosolic fraction without affecting bax expression, and 4) increases in activity of caspases-3 and -9. These changes were accentuated when the cells were cultured at pH 7.0. In the absence of NH(4)Cl, none of these changes was detected at any pH examined. These results suggest that gastric luminal ammonia, at concentrations detected in H. pylori-infected subjects, induces apoptosis of gastric epithelial cells by release of cytochrome c from mitochondria, followed by activation of caspases-9 and -3, especially at higher ambient pH.