Omeprazole and gastric polyposis in humans

Sporadic Fundic Gland Polyps and Gastric Acid Suppression Level

BACKGROUND

Fundic gland polyps (FGPs) are a common endoscopic finding and are known to be associated with proton pump inhibitors (PPIs) use. It is not known if their prevalence is affected by gastric acidity levels. This study aimed to assess whether there is a correlation between FGPs and gastric acidity levels as identified on 24-hour ambulatory impedance-pH studies in patients on PPI therapy.

METHODS

We performed a review of 402 consecutive patients who take at least once daily PPI and underwent esophagogastroduodenoscopy with combined impedance-pH studies in the same setting (time and place) between January 2010 and December 2014. Patients were classified into 2 groups based on the presence or absence of biopsy-confirmed FGPs during endoscopy.

RESULTS

Of the 402 patients, 30 (7%) had FGPs. One of these polyps was found with low-grade dysplasia. There was no significant difference of the distributions of the [H⁺] in the FGPs versus the nonpolyp groups (P = 0.741). There was no significant difference between the 2 groups regarding PPI dose frequency regimens (once and twice) (P = 0.074). However, we found weak ordinal association with PPI duration (P = 0.01) (Spearman = 0.1).

CONCLUSIONS

FGPs are common endoscopic lesions. Incidence of dysplasia in FGPs is not only rare, but also of unknown clinical significance. Although they seem to be associated with PPIs, the mechanism remains unclear, as we found no correlation between the presence of FGPs and gastric acid control or PPI dose. Future studies would be useful to elucidate an alternate mechanism.

A Clinicopathologic Evaluation of Incidental Fundic Gland Polyps With Dysplasia: Implications for Clinical Management

OBJECTIVES

Fundic gland polyps (FGPs) can rarely exhibit dysplasia of the surface epithelium. Based on retrospective data, FGPs with dysplasia (FGPDs) are thought to be a strong marker for familial adenomatous polyposis (FAP), although sporadic, non-syndromic FGPDs also occur. Owing to the significant syndromic association, diagnosis of an apparently sporadic FGPD may prompt clinical evaluation for FAP, especially its attenuated variant. We sought to evaluate the positive predictive value of incidental FGPDs for FAP. We also characterized the clinicopathologic features of incidental FGPDs to advance clinical management.

METHODS

Incidental FGPDs were identified from 2004 to 2015 in patients without FAP at biopsy. All clinical follow-up data were reviewed, and germline analysis for APC and MUTYH mutations was performed in consenting patients.

RESULTS

We identified 25 incidental FGPDs in patients not known to have FAP (11.6% of FGPDs, 1.0% of all FGPs). Four patients had a family history of gastric polyps or gastrointestinal cancers. Clinical management included completion polypectomy and gastric endoscopic surveillance (44%), endoscopic surveillance alone (32%), no follow-up (24%), colonoscopy referral (12%), and genetic counseling (4%). Colonoscopies on record revealed 0-7 cumulative adenomas. Follow-up averaged 4.4 years (range 0.3-10.6). No clinical evidence of FAP, gastric cancer, death, or surgery occurred. None of the 11 patients consenting to germline APC and MUTYH testing had genomic alterations.

CONCLUSIONS

Incidental FGPDs in this series were all found to be sporadic (25/25) by endoscopic, clinical, and molecular findings, and thus FGPDs were not harbingers of FAP. As isolated findings, FGPDs do not appear to warrant follow-up genetic counseling or testing.

Use of Proton Pump Inhibitors and Risks of Fundic Gland Polyps and Gastric Cancer: Systematic Review and Meta-analysis

BACKGROUND & AIMS

There have been increasing numbers of case reports and observational studies of adverse events in patients receiving long-term therapy with proton pump inhibitors (PPIs). The effects of PPI therapy on risks of fundic gland polyps (FGPs) and gastric cancer have received considerable attention. We performed a systematic review with a meta-analysis of randomized controlled trials and observational studies that assessed these risks.

METHODS

We searched the PUBMED, EMBASE, and Cochrane Central Register of Controlled Trials databases for relevant studies published through July 2015. We calculated pooled odds ratio for FGPs and the risk ratio for gastric cancer in PPI users compared with PPI nonusers using fixed- and random-effects models.

RESULTS

We analyzed data from 12 studies, comprising more than 87,324 patients: 1 randomized controlled trial reporting the effect of PPIs on gastric polyps (location not specified), 6 cohort and 1 case-control studies on FGPs, and 1 cohort and 3 case-control studies on gastric cancer. Pooled odds ratios for FGPs were 1.43 (95% confidence interval, 1.24-1.64) and 2.45 (95% confidence interval, 1.24-4.83) from fixed- and random-effects models, respectively. The pooled risk ratio for gastric cancer was 1.43 (95% confidence interval, 1.23-1.66) from each model. We observed significant heterogeneity among studies reporting on FGPs, but not among studies reporting on gastric cancer.

CONCLUSIONS

Based on a systematic review with meta-analysis, long-term use of PPIs (≥12 months) is associated with an increased risk of FGPs. PPI therapy might also increase the risk of gastric cancer, but this association could be biased, because of the limited number of studies and possible confounding factors.

Systematic review with meta-analysis: fundic gland polyps and proton pump inhibitors

BACKGROUND

A causal association between proton pump inhibitor (PPI) use and fundic gland polyps has been suggested, but the data are conflicting.

AIM

To clarify the relationship through a meta-analysis of the existing data.

METHODS

A systematic retrieval and selection of records was performed. The main inclusion criteria were original studies reporting the prevalence of fundic gland polyps in PPI users or the reverse, compared to controls. Key outcomes were the odds ratios (OR) for fundic gland polyp prevalence in association with PPI use, prevalence of PPI use amongst subjects with fundic gland polyps and fundic gland polyp prevalence among PPI users. Statistical analysis was performed using Mix 2.0 Pro.

RESULTS

The initial search using electronic databases and manual searching retrieved 339 peer-reviewed articles and abstracts. Twenty articles met all inclusion and exclusion criteria, with a total of 40 218 subjects included. The meta-analysis of 12 studies revealed an increase in fundic gland polyps amongst PPI users compared to controls (OR 2.46, 95% CI 1.42-4.27, P = 0.001), particularly among individuals taking PPIs for at least 6 months (OR: 4.71, 95% CI 2.22-9.99, P < 0.001) or 12 months (OR: 5.32, 95% CI 2.58-10.99, P < 0.001).

CONCLUSIONS

Proton pump inhibitor usage is associated with a significantly increased prevalence of fundic gland polyps, and there is a trend for this to increase with longer length of PPI exposure. However, the meta-analysis is limited mainly to cohort studies.

Current Status of Gastric Proton Pump Inhibitors in the Treatment of Acid-Peptic Disease

Proton pump inhibitors represent an important advance in the treatment of acid-peptic disease. Omeprazole, the prototype of the drug class, produces a profound and sustained degree of gastric acid suppression. Recent studies confirm earlier reports that omeprazole 20 mg/d is generally more effective than standard histamine2 receptor antagonist (H2RA) dosage regimens in treating duodenal ulcer (DU), gastric ulcer (GU), and erosive esophagitis. Omeprazole tends to accelerate DU and GU healing, especially during the first 2 weeks of treatment, and also accelerates mucosal healing in patients with all grades of esophagitis. Omeprazole is the drug of choice for treating patients with large or refractory ulcers, severe or refractory erosive esophagitis, Barrett's esophagus, and Zollinger-Ellison syndrome. Maintenance therapy with omeprazole seems to reduce ulcer recurrence and esophagitis, but optimal treatment regimens must be established. Dual therapy with omeprazole and amoxicillin shows encouraging results in eradicating Helicobacter pylori, reducing duodenal ulcer recurrence rates, and altering the natural history of peptic ulcer disease. Further studies are required to determine the efficacy of omeprazole in preventing nonsteroidal anti-inflammatory drug-induced ulcers and stress-related mucosal bleeding, and in treating upper gastrointestinal bleeding. Omeprazole is well-tolerated in the majority of patients receiving either short-term or long-term treatment. The type and frequency of adverse effects are similar to those reported with the H2RAs. There is no evidence to support genotoxicity or hypergastrinemia-induced enterochromaffin-like cell carcinoid of the stomach in patients receiving omeprazole treatment for more than 5 years. Omeprazole interacts selectively with hepatic P-450 and may potentially interact with phenytoin, warfarin, or diazepam. Pharmacoeconomic studies suggest that treatment with omeprazole provides a significant cost-savings over the H2RAs in patients with moderate to severe erosive esophagitis and possibly in patients with DU. Lansoprazole, a newly developed proton pump inhibitor, seems to offer no clear advantage over omeprazole.

Incidence and risk factor of fundic gland polyp and hyperplastic polyp in long-term proton pump inhibitor therapy: a prospective study in Japan

GOAL

To investigate the development of fundic gland polyp (FGP) and gastric hyperplastic polyp (HPP) during long-term proton pump inhibitor (PPI) therapy and risk factors of each polyp via patient status in a multicenter prospective study.

BACKGROUND

The risk of developing FGP may increase during long-term PPI therapy. However, the association with PPI-induced hypergastrinemia is unclear. Helicobacter pylori (Hp) infection (which there is a high rate of in Japan) may influence the development of HPP.

METHODS

Reflux esophagitis patients on PPI maintenance therapy were enrolled. At baseline, the presence of protruding lesion (gastric polyps) and mucosal atrophy was examined endoscopically. The serum gastrin level (SGL) and Hp infection status were noted. The patients took rabeprazole 10 mg/day for 104 weeks and endoscopy was performed at weeks 24, 52, 76, and 104 to check for newly developed FGPs and HPPs. The hazard ratios (HRs) of risk factors were calculated.

RESULTS

191 patients were analyzed. The distribution of patients with baseline SGLs (pg/mL) of <200, >or=200 to <400, and >or=400 was 118 (61.8%), 51 (26.7%), and 22 (11.5%), respectively. 78 (40.8%) patients were Hp-positive, and gastric polyps were found in 70 (36.6%) patients. By the end of rabeprazole therapy, 26 (13.6%) and 17 (8.9%) patients had developed new FGPs and HPPs. In terms of risk factors, Hp-positive was significantly lower (HR=0.288; 95% CI, 0.108-0.764) for FGP while SGL>or=400 pg/mL was significantly higher (HR=4.923; 95% CI, 1.486-16.31) for HPP.

CONCLUSION

During long-term PPI therapy, FGP development was associated with absence of Hp infection. Meanwhile, Hp infection and high SGL may influence HPP development.

Serum gastrin and chromogranin A levels in patients with fundic gland polyps caused by long-term proton-pump inhibition

OBJECTIVE

Use of proton-pump inhibitors (PPIs) causes hypergastrinemia, and it is well known that gastrin has a trophic effect on the oxyntic mucosa. Some PPI users develop fundic gland polyps. The purpose of this study was to determine whether patients developing fundic gland polyps have a more pronounced gastric hypoacidity, hypergastrinemia or increased serum chromogranin A (CgA), which is an enterochromaffin-like (ECL) cell marker.

MATERIAL AND METHODS

Five PPI users who developed multiple fundic gland polyps during PPI use were included in the study. PPI users without fundic gland polyps (n = 6) as well as healthy individuals (n = 6) were used as controls. In PPI users, we measured 24-h gastric pH, serum gastrin and CgA during one day, with standardized meals, whereas only gastrin and CgA were measured in the healthy individuals. Helicobacter pylori status was determined.

RESULTS

Gastric pH, serum gastrin and CgA did not differ significantly between PPI users with and those without fundic gland polyps. All patients with fundic gland polyps were H. pylori negative, whereas 4 out of 6 PPI users without fundic gland polyps were H. pylori positive. Fasting CgA levels were elevated in all PPI users, and CgA more than doubled during the day in all groups.

CONCLUSIONS

Fundic gland polyps induced by PPIs are not related to the level of hypergastrinemia. Serum CgA is markedly affected by meals and should be measured in samples from fasting patients.

Increased risk of fundic gland polyps during long-term proton pump inhibitor therapy

BACKGROUND

It is controversial whether proton pump inhibitor use leads to fundic gland polyp development.

AIM

To determine whether fundic gland polyp development is due to proton pump inhibitor use and to investigate mechanisms involved.

METHODS

Proton pump inhibitor use and the presence of fundic gland polyps were assessed in consecutive patients undergoing oesophagogastroduodenoscopy. Biopsies from fundic gland polyps and gastric mucosa were taken. Dysplasia was graded as negative, low or high grade. Prevalence of parietal cell hyperplasia and parietal cell protrusions and the proportional cystic area were assessed.

RESULTS

599 patients participated, 322 used proton pump inhibitors, 107 had fundic gland polyps. Long-term proton pump inhibitor use was associated with an increased risk of fundic gland polyps (1-4.9 years use: OR 2.2, 95% CI: 1.3-3.8; > or =5 years: OR 3.8, 95% CI: 2.2-6.7) while short-term therapy (<1 year) was not (OR 1.0, 95% CI: 0.5-1.8). Low-grade dysplasia was found in one fundic gland polyp. Fundic gland polyps associated with long-term proton pump inhibitor use had a larger proportional cystic area and higher frequency of parietal cell hyperplasia and parietal cell protrusion.

CONCLUSIONS

Long-term proton pump inhibitor use is associated with an up to fourfold increase in the risk of fundic gland polyps. Risk of dysplasia is negligible. Aetiologically, these polyps seem to arise because of parietal cell hyperplasia and parietal cell protrusions resulting from acid suppression.

High-grade dysplasia in sporadic fundic gland polyps: a case report and review of the literature

We present a case of fundic gland polyps (FGPs) containing high-grade dysplasia in a 68-year-old man. High-grade dysplasia, and even gastric adenocarcinoma, associated with FGPs have been described in patients with familial adenomatous polyposis (FAP) and attenuated familial adenomatous polyposis (AFAP) but never in non-FAP patients. Two colonoscopies in the past six years virtually rule out FAP and AFAP in our patient. Dysplasia in FGPs from non-FAP patients is extremely rare, and until now only cases of low-grade dysplasia have been described. The literature on dysplasia in FGPs is reviewed briefly. Additional immunohistochemical investigations in this case showed nuclear staining of beta-catenin, increased proliferation and apoptosis in the dysplastic areas of the FGPs. Our case suggests that the malignant potential of FGPs is not limited to FAP-associated FGPs.

Sporadic fundic gland polyps with epithelial dysplasia : evidence for preferential targeting for mutations in the adenomatous polyposis coli gene

Gastric fundic gland polyps (FGPs) occur in two distinct clinicopathological scenarios: sporadic and familial adenomatous polyposis (FAP) associated. FAP-associated FGPs arise through somatic second hit alterations of the adenomatous polyposis coli (APC) gene and frequently demonstrate epithelial dysplasia (Am J Pathol 2000, 157:747-754). Sporadic FGPs, in contrast, tend to contain beta-catenin gene mutations and only infrequently show dysplasia (Am J Pathol 2001, 158:1005-1010). However, sporadic FGPs with dysplasia have not been previously investigated. We studied 13 sporadic FGPs with surface/foveolar low-grade dysplasia or changes indefinite for dysplasia for alterations in the APC/beta-catenin pathway, using chromosome 5q allelic loss assays and direct DNA sequencing of the mutation cluster region in exon 15 of APC and the phosphorylation region in exon 3 of beta-catenin. In addition, to evaluate for possible additional genetic alterations in FGPs, all cases were evaluated for microsatellite instability using fluorescent-based amplification of a standard panel of five microsatellite markers. Alterations in APC were present in seven (53.8%) FGPs, including two cases with bi-allelic APC inactivation (truncating intragenic mutation plus 5q allelic loss), two cases with APC mutation only, and three cases with 5q allelic loss only. In contrast, only two (15.4%) FGPs contained stabilizing beta-catenin mutations. All 13 FGPs were microsatellite stable. These results indicate that sporadic FGPs with dysplasia/indefinite for dysplasia are molecularly similar to FAP-associated FGPs, and are dissimilar to the more common sporadic nondysplastic FGPs. Mutations in APC and beta-catenin, despite occurring in the same genetic pathway, show differing biological properties, a phenomenon that has previously been demonstrated in colorectal neoplasms. The lack of microsatellite instability in FGPs in this study and of K-ras mutations in a previous study suggests that secondary genetic alterations are rare in both dysplastic and nondysplastic FGPs.

Long-term safety of proton pump inhibitors: risks of gastric neoplasia and infections

After Helicobacter pylori eradication was introduced and largely eliminated the need for maintenance therapy for peptic ulcer disease, gastroesophageal reflux disease (GERD) became the main indication for prolonged gastric acid inhibition. The drug effect on GERD depends on the degree of acid inhibition, thus the efficacious proton pump inhibitors are preferred. The proton pump inhibitors have few immediate side effects, the main concern being the profound hypoacidity and hypergastrinaemia they induce. In short-term, hypergastrinaemia causes rebound hyperacidity, possibly worsening GERD and reducing the efficacy of histamine H(2) blockers. In the long-term, hypergastrinaemia causes enterochromaffin-like cell hyperplasia and carcinoids. Since enterochromaffin-like cells may be important in gastric carcinogenesis, iatrogenic hypergastrinaemia may predispose to carcinoma. Gastric hypoacidity also increases gut bacterial infections, and the barrier function of acid against viral and prion infections requires further assessment.

Gastric mucosal morphological consequences of acid suppression: a balanced view

In the chapter, an analysis of the literature on the relationship between Helicobacter pylori, the use of proton pump inhibitors and the development of atrophic gastritis is presented, and the difficulties of classifying gastritis and the new possibilities of quantifying chronic inflammation by morphometric analysis are discussed. The issue surrounding the necessity of eradicating H. pylori in H. pylori-positive patients has still not been solved. Most studies have now accepted that proton pump inhibitors indeed accelerate the onset of atrophic gastritis in H. pylori-positive patients, but evidence against such an association was published in one recent (Scandinavian) study; conclusions from this study have, however, been challenged by several groups. Some data are available on the efficacy of H. pylori eradication with regard to the prevention of atrophy. The limited significance of the development of parietal cell protrusions and fundic gland cysts is better understood, but much less is known of the development and long-term consequence of H. pylori-induced autoimmune gastritis. Finally, recent studies in H. pylori-positive patients indicate that treatment with proton pump inhibitors may promote bacterial N-nitrosation formation. These data taken together suggest that the eradication of H. pylori may be based not only on morphological arguments, but also on bacterial alterations in the gastric milieu.

Personal review: is profound acid inhibition safe?

Inhibitors of gastric acid secretion, particular proton pump inhibitors, are effective drugs in the treatment and prophylaxis of acid-related diseases. Proton pump inhibitors are therefore prescribed widely, often for minor complaints. Gastric acidity kills swallowed microorganisms, and acid secretion must be of biological importance because it is maintained in phylogenesis. Acid secretion is controlled by feedback mechanisms, mainly via gastrin. A decrease in acidity always causes an increase in plasma gastrin. The trophic effect of gastrin leads to hyperplasia and neoplasia of the enterochromaffin-like (ECL) cell. ECL cell derived tumours in man were previously regarded as rare, and also as rather benign. It is now clear that the ECL cell gives rise to a significant proportion of gastric carcinomas. Moreover, ECL cell carcinoids secondary to hypergastrinaemia may develop into highly malignant tumours. Treatment with a proton pump inhibitor is followed by rebound acid hypersecretion and decreased efficiency of H2-blockers, thus such treatment may induce a type of physical dependence. It is therefore reasonable to be cautious and not to treat younger (< 50 years) patients for long periods of time with profound inhibitors of gastric acid secretion. Chromogranin A in the blood is a sensitive marker of the ECL cell mass, and it could be used to survey patients on long-term proton pump inhibitors.

Parietal cell protrusions in gastric ulcer disease

Oxyntic mucosal biopsy specimens from patients receiving omeprazole therapy have been described as frequently showing characteristic tonguelike protrusions of parietal cell cytoplasm (PCP) into the gland lumen. Although protrusion of parietal cell cytoplasm is believed to be associated with omeprazole therapy and has been implicated in the histogenesis of fundic gland polyps, we have observed it in a wide variety of different conditions unrelated to peptic ulcer disease or omeprazole therapy. To establish the incidence of PCP and analyze its relationship to gastritis, gland dilatation, cystic change, and fundic gland polyps, we studied 400 gastric mucosal biopsy specimens from gastric ulcer patients who were not receiving omeprazole therapy and who did not receive any medications for at least 2 weeks. Severity of each of these changes was graded on a scale of I to III. PCP was observed in oxyntic mucosal biopsy specimens from 60 (15%) patients and was associated with varying grades of chronic superficial or interstitial gastritis in 25 (Helicobacter pylori was identified in 12). Although chronic atrophic gastritis, cystic change, or fundic gland polyps were not identified in any of the cases with PCP, gland dilatation was present in 25 of 60 (42%) biopsy specimens. No consistent linear correlation was observed between increasing grades of PCP and gastritis or gland dilatation. Our findings of PCP in 15% of gastric ulcer patients who were off all medications for 2 weeks indicate that PCP is not always related to omeprazole usage. It appears to be a change encountered in a wide variety of diverse settings and, therefore, should not be used to monitor omeprazole therapy. In gastric ulcer patients, there is no linear correlation between PCP and gland dilatation or severity of gastritis. The lack of association of PCP with such cardinal features of fundic gland polyps as gland dilatation and cystic change suggests that PCP per se has little if any role in the development of such polyps. The exact clinical and functional significance of PCP remain to be established and merits further investigation.

Review article: infective complications of therapeutic gastric acid inhibition

Gastric acid secretion has a non-specific bactericidal action which contributes to gastrointestinal defence mechanisms against micro-organisms. Therapeutic inhibition of acid secretion with histamine H2 receptor antagonists and proton pump inhibitors might therefore be expected to predispose to infection. This article reviews clinical reports of infection occurring during therapeutic gastric acid inhibition, and assesses the risk of infection incurred by such treatment. Non-typhoid salmonelloses, Campylobacter infections, local candidiasis, and possibly Strongyloides hyperinfections may be more prevalent after acid inhibitory treatment, but concurrent impairment of other gastrointestinal defence mechanisms may be necessary to permit infection.