Elevated serum gastrin is associated with a history of advanced neoplasia in Barrett's esophagus

Promises and Limitations of Current Models for Understanding Barrett's Esophagus and Esophageal Adenocarcinoma

BACKGROUND & AIMS

This review was developed to provide a thorough and effective update on models relevant to esophageal metaplasia, dysplasia, and carcinogenesis, focusing on the advantages and limitations of different models of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC).

METHODS

This expert review was written on the basis of a thorough review of the literature combined with expert interpretation of the state of the field. We emphasized advances over the years 2012-2023 and provided detailed information related to the characterization of established human esophageal cell lines.

RESULTS

New insights have been gained into the pathogenesis of BE and EAC using patient-derived samples and single-cell approaches. Relevant animal models include genetic as well as surgical mouse models and emphasize the development of lesions at the squamocolumnar junction in the mouse stomach. Rat models are generated using surgical approaches that directly connect the small intestine and esophagus. Large animal models have the advantage of including features in human esophagus such as esophageal submucosal glands. Alternatively, cell culture approaches remain important in the field and allow for personalized approaches, and scientific rigor can be ensured by authentication of cell lines.

CONCLUSIONS

Research in BE and EAC remains highly relevant given the morbidity and mortality associated with cancers of the tubular esophagus and gastroesophageal junction. Careful selection of models and inclusion of human samples whenever possible will ensure relevance to human health and disease.

The Impact of Sex on the Response to Proton Pump Inhibitor Treatment

Proton pump inhibitor (PPI) treatment is responsible for substantial gastrin elevation secondary to reduced intragastric acidity. Due to the increasing global prevalence of PPI users, concerns have been raised about the clinical significance of continuous gastrin elevation and its potential long-term side effects. Hypergastrinemia secondary to PPIs has trophic effects on gastric mucosa, leading to enterochromaffin-like cell hyperplasia and gastric (fundic) polyp formation, and it is believed to provoke acid rebound following PPI withdrawal that induces PPI overutilization. Previous studies have found higher gastrin release following PPI therapy in females compared with males, and sex differences have also been demonstrated in pharmacokinetic parameters and dose requirements for acid reflux. It is conceivable that females might be at increased risk of PPI overuse, because they often receive higher milligram-per-kilogram doses. The prevalence of PPI use is more common among females, and the female sex is a risk factor for adverse drug reactions. This non-systematic review outlines the current knowledge of the impact of biological sex on the response to PPIs. The aim is to highlight the female sex as a potential risk factor that could be a step toward precision medicine and should be considered in future research on the response to PPI treatment.

Proton Pump Inhibitors and Cancer Risk: An Umbrella Review and Meta-analysis of Observational Studies

OBJECTIVES

Increasing evidence suggested that proton pump inhibitors (PPIs) use might affect the development of cancers, but previous conclusions remain controversial. Therefore, an umbrella review was performed to clarify the associations between PPIs and various types of cancer by summarizing the existing meta-analyses and systematic reviews.

METHODS

We searched PubMed, Cochrane Library, Embase, CNKI, Wanfang, and VIP database up to June 2022 for eligible meta-analyses or systematic reviews. The summary effect size, 95% CI, heterogeneity, small study effect, and 95% prediction interval were considered in the present study. A Measurement Tool to Assess Systematic Review 2 and grading of recommendation, assessment, development, and evaluation were used to assess methodological quality and evidence.

RESULTS

The umbrella review included 21 meta-analyses containing 65 studies and 10 cancer types with 6.8 million subjects. The results showed that PPI use was significantly associated with increased risks of certain types of cancer, including gastric cancer (odds ratio [OR]: 2.07; 95% CI, 1.30 to 3.29), pancreatic cancer (OR: 1.73; 95% CI, 1.23 to 2.44), colorectal cancer (OR: 1.84; 95% CI, 1.26 to 2.67), and liver cancer (OR: 1.80; 95% CI, 1.27 to 2.54), but was not associated with esophageal cancer. In addition, PPI use was associated with decreased risk of breast cancer (OR: 0.69; 95% CI, 0.50 to 0.96).

CONCLUSIONS

These findings suggested that clinicians should pay more attention to the occurrence of gastric cancer, pancreatic cancer, colorectal cancer, and liver cancer in patients who used PPIs, and PPI prescription should be written only when an accurate specific diagnosis has been made. Furthermore, additional PPIs to the treatment regimen may be benefit for women with a higher-than-average risk of breast cancer.

Randomized Controlled Trial of the Gastrin/CCK2 Receptor Antagonist Netazepide in Patients with Barrett's Esophagus

Hypergastrinemia has been associated with high-grade dysplasia and adenocarcinoma in patients with Barrett's esophagus, and experimental studies suggest proinflammatory and proneoplastic effects of gastrin on Barrett's esophagus. This is of potential concern, as patients with Barrett's esophagus are treated with medications that suppress gastric acid production, resulting in increased physiologic levels of gastrin. We aimed to determine whether treatment with the novel gastrin/CCK₂ receptor antagonist netazepide reduces expression of markers associated with inflammation and neoplasia in Barrett's esophagus. This was a randomized, double-blind, placebo-controlled trial of netazepide in patients with Barrett's esophagus without dysplasia. Subjects were treated for 12 weeks, with endoscopic assessment at baseline and at end of treatment. The primary outcome was within-individual change in cellular proliferation as assessed by Ki67. Secondary analyses included changes in gene expression, assessed by RNA-sequencing, and safety and tolerability. A total of 20 subjects completed the study and were included in the analyses. There was no difference between arms in mean change in cellular proliferation (netazepide: +35.6 Ki67+ cells/mm², SD 620.7; placebo: +307.8 Ki67+ cells/mm², SD 640.3; P = 0.35). Netazepide treatment resulted in increased expression of genes related to gastric phenotype (TFF2, MUC5B) and certain cancer-associated markers (REG3A, PAX9, MUC1), and decreased expression of intestinal markers MUC2, FABP1, FABP2, and CDX1 No serious adverse events related to study drug occurred. The gastrin/CCK₂ receptor antagonist netazepide did not reduce cellular proliferation in patients with nondysplastic Barrett's esophagus. Further research should focus on the biological effects of gastrin in Barrett's esophagus.Prevention Relevance: Treatment of patients with Barrett's esophagus with a gastrin/CCK₂ receptor antagonist did not have obvious chemopreventive effects.

Pharmacokinetics of single and repeated oral doses of esomeprazole and gastrin elevation in healthy males and females

OBJECTIVE

Gastrin elevation secondary to proton pump inhibitor (PPI) therapy is well documented. Recent studies have demonstrated a sex-related difference where females on PPIs have significantly higher baseline gastrin levels than males. The aim of the study was to analyse the pharmacokinetics of esomeprazole and short-term effect on serum gastrin levels and evaluate potential sex-related difference.

MATERIALS AND METHODS

Healthy volunteers received 40 mg of esomeprazole daily for five days. After the 1st and 5th dose blood samples for fasting gastrin and pharmacokinetic analysis were collected at scheduled time-points for eight hours. Esomeprazole was analysed by liquid chromatography and gastrin concentrations were measured using radioimmunoassay.

RESULTS

A total of 30 volunteers were enrolled. Females had higher median baseline gastrin (pM) than males 12 (IQR 10-15) vs. 7 (IQR 4-11) (p = .03). In the study cohort, median gastrin levels rose from 10 (IQR 6-14) to 15 (IQR 13-20) (p = .0002). The serum levels for esomeprazole increased by an average of 299.8 ng/mL (p < .001) from day 1 to day 5. Comparison of the esomeprazole pharmacokinetic parameters between males and females revealed no significant sex-related differences. No significant correlation was found between the AUC and the gastrin level on day 5 (p = .15).

CONCLUSIONS

In healthy volunteers, serum gastrin increased significantly after a four-day PPI-therapy. There was also a significant increase in serum esomeprazole from day 1 to day 5. The increase in gastrin and esomeprazole concentration was not related to sex and no significant sex-related difference was found in terms of pharmacokinetic parameters. European Clinical Trial Database (2015-002230-41).

Current Status of Chemoprevention in Barrett's Esophagus

Candidates for chemoprevention in Barrett's esophagus have long been suggested and there has been observational data to support many drugs, including statins, hormone replacement therapy, metformin, proton pump inhibitor therapy, and aspirin. Proton pump inhibitor therapy and aspirin are the most promising agents. Data suggest that aspirin and proton pump inhibitor therapy can decrease the risk of neoplastic progression in Barrett's esophagus. Further, the combination of aspirin and proton pump inhibitor therapy decrease all-cause mortality by approximately 33%. Future guideline groups need to evaluate the evidence rigorously, but the combination of proton pump inhibitor therapy and aspirin is promising.

Effects of Proton Pump Inhibitor Therapy, H. pylori Infection and Gastric Preneoplastic Pathology on Fasting Serum Gastrin Concentrations

BACKGROUND

Hypergastrinaemia occasionally indicates the presence of a gastrinoma. However it is much more commonly associated with various benign causes including proton pump inhibitor (PPI) use, Helicobacter pylori infection and/or atrophic gastritis. The extent to which these factors interact to influence fasting serum gastrin concentrations remains incompletely understood.

MATERIALS AND METHODS

Fasting serum gastrin concentrations were measured by radioimmunoassay in 1,400 patients attending for diagnostic oesophagogastro-duodenoscopy. After exclusions, 982 patients were divided into four groups and their results analysed. We compared gastrin concentrations in normal patients (no H. pylori infection, no PPI use and no histological evidence of gastric preneoplasia (n=233)), with those in patients who were taking regular PPIs (H. pylori negative with no gastric preneoplasia (n=301)), patients who had active H. pylori infection but no gastric preneoplasia (n=164) and patients with histologically confirmed gastric preneoplasia (n=284).

RESULTS

Median fasting gastrin concentration in the normal group was 20pM and was significantly increased in PPI users (46pM, p<0.0001), patients with active H. pylori infection (27pM, p<0.0001), and patients with antral (25pM, p<0.01) or corpus (48pM, p<0.0001) gastric preneoplasia. PPI use resulted in further significant increases in fasting serum gastrin concentrations in patients who were infected with H. pylori (50pM, n=56) or who had antral gastric preneoplasia (53pM, n=87), but did not significantly alter serum gastrin concentrations in patients with corpus preneoplasia (90pM, n=66).

CONCLUSIONS

PPI use, H. pylori infection and atrophic gastritis all caused significant elevations of median fasting gastrin concentrations. However, several patients who had potential risk factors for hypergastrinaemia still demonstrated fasting serum gastrin concentrations within the normal range.

Proton pump inhibitors and odds of cholangiocarcinoma: A retrospective case-control study

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) have been reported to be associated with cholangitis and might possibly be carcinogenic. However, few studies have been conducted to investigate the association of PPIs with cholangiocarcinoma (CCA). Thus, a hospital-based case-control study was carried out in China to explore the association between PPIs and CCA.

METHODS

In this study, 1468 CCA cases (826 intrahepatic cholangiocarcinoma (ICC) and 642 extrahepatic cholangiocarcinoma (ECC)) were included, which were observed at Beijing Friendship Hospital, from February 2002 to October 2018. We retrospectively extracted PPI use and other possible risk factors from clinical records, followed by an investigation of the relationship with CCA via calculation of odds ratios (ORs), adjusted odds ratios (AORs), and 95% confidence intervals (CIs) using logistic regression analysis.

RESULTS

PPIs were used by 135 (9.2%) CCA cases and 173 (5.9%) controls. We found that PPI use was associated with a 1.61-fold elevated CCA odds (P < .001) (AOR = 1.61, 95% CI = 1.28-2.05; P < .001). After stratification by CCA subtypes, the AORs of PPIs were consistent for both CCA subtypes, with ORs of 1.36 (AOR = 1.36, 95% CI = 1.02-1.83; P = .003) and 1.95 (AOR = 1.95, 95% CI = 1.46-2.62; P < .001) for ICC and ECC respectively. Our results also showed that PPI use was slightly linked to the odds of CCA in a dose-dependent manner.

CONCLUSION

PPI use was correlated with a significant 61% increased odds of CCA, particularly in the ECC. However, the retrospective design and observational nature cannot establish causation. Larger scale, multi-centre prospective studies are required for further validation.

Predictors of Gastrin Elevation Following Proton Pump Inhibitor Therapy

GOALS

The goal of this study was to elucidate the most important predictors for elevation of gastrin in patients on long-term PPI therapy through analysis of data from 2 published studies in Icelandic patients with erosive GERD.

BACKGROUND

Gastrin elevation is a known but variable consequence of proton pump inhibitor (PPI) therapy. Concerns have been raised about the clinical importance of chronic PPI induced gastrin elevation.

STUDY

This cross-sectional analysis included patients with endoscopically verified erosive esophagitis receiving long-term PPI therapy. PPI exposure in dosage over weight (mg/kg) and dosage over body surface area (mg/m) was compared with fasting gastrin levels in two separate multiple linear regression models. Data was collected on age, gender, weight, H. pylori infection, smoking, PPI duration and type.

RESULTS

Overall data from 157 patients (78 females) were analyzed. Median serum gastrin levels were higher in females than males (92 vs. 60 pg/mL; P=0.001). Simple linear regression showed a correlation between serum gastrin levels and gender (P=0.0008) as well as PPI exposure in mg/kg (P=0.0001) and mg/m (P=0.0001). Multiple linear regression analysis showed that PPI exposure, both in mg/kg (β=0.95 [CI=0.4-1.5]; P=0.001) and mg/m (β=0.02 [CI=0.0-0.0]; P=0.0015) along with female gender (β=0.2 [CI=0.0-0.4]; P=0.02) predicted higher gastrin values.

CONCLUSIONS

Dosage and female gender seem to play an important role in the development of gastrin elevation on PPI therapy. A significant correlation was found between fasting serum gastrin and dosage of PPIs over weight and body surface area.

Relationship between Barrett's esophagus and colonic diseases: a role for colonoscopy in Barrett's surveillance

BACKGROUND

Given that risk factors for Barrett's carcinogenesis are predictive, appropriate management and surveillance of Barrett's esophagus (BE) may be provided. The presence of colorectal neoplasms (CRNs) is a possible predictor of the development of BE and the progression to esophageal adenocarcinoma (EAC). We evaluated the relationship between BE or EAC and colonic diseases, including neoplasms and diverticulosis.

METHODS

Patients (N = 5606) who underwent both colonoscopy and esophagogastroduodenoscopy between January 2016 and December 2017 at three institutions were enrolled. The relationships between the presence of colonic diseases and BE or EAC and other clinical or endoscopic predictors of the presence of BE were investigated retrospectively.

RESULTS

The prevalence of BE ≥ 1 cm and ≥ 3 cm in length was 13.0% and 0.52%, respectively. BE was closely related with the presence of colorectal adenoma (48.4% vs. 37.2% in non-BE; P < 0.001), adenocarcinoma (16.6% vs. 8.4%, P < 0.001) and colonic diverticulosis (CD) (34.1% vs. 29.3%, P < 0.001). In patients with long-segment BE, CRNs (79.3%, P < 0.001) and CD (48.2%, P = 0.038) were more common. EAC patients also had a statistically significantly higher incidence of CRNs than non-BE patients (87.5% vs. 45.6%, P = 0.027). Diverticulosis at the distal colon correlated significantly with EAC and BE (50.0%, P = 0.010 and 15.4%, P = 0.024, vs. 12.0% in non-BE). Multivariate analysis showed that CRNs (t = 8.55, P < 0.001), reflux esophagitis (t = 5.26, P < 0.001) and hiatal hernia (t = 11.68, P < 0.001) were predictors of BE.

CONCLUSIONS

The presence of CRNs was strongly associated with BE and EAC. Therefore, colonoscopy may be useful for establishing a strategy for the surveillance of BE.

Origins of Metaplasia in the Esophagus: Is This a GE Junction Stem Cell Disease?

The incidence of esophageal adenocarcinoma (EAC) and its precursor lesion Barrett's esophagus (BE) has been increasing steadily in the western world in recent decades. Understanding the cellular origins of BE and the conditions responsible for their malignant transformation would greatly facilitate risk assessment and identification of patients at risk of progression, but this topic remains a source of debate. Here, we review recent findings that have provided support for the gastroesophageal junction (GEJ) as the main source of stem cells that give rise to BE and EAC. These include both gastric cardia cells and transitional basal cells. Furthermore, we discuss the role of chronic injury and inflammation in a tumor microenvironment as a major factor in promoting stem cell expansion and proliferation as well as transformation of the GEJ-derived stem cells and progression to EAC. We conclude that there exists a large amount of empirical support for the GEJ as the likely source of BE stem cells. While BE seems to resemble a successful adaptation to esophageal damage, carcinogenesis appears as a consequence of natural selection at the level of GEJ stem cells, and later glands, that expand into the esophagus wherein the local ecology creates the selective landscape for cancer progression.

Gastrin stimulates a cholecystokinin-2-receptor-expressing cardia progenitor cell and promotes progression of Barrett's-like esophagus

Objective

The incidence of esophageal adenocarcinoma (EAC) is increasing, but factors contributing to malignant progression of its precursor lesion, Barrett's esophagus (BE), have not been defined. Hypergastrinemia caused by long-term use of proton pump inhibitors (PPIs), has been suggested as one possible risk factor. The gastrin receptor, CCK2R, is expressed in the cardia and upregulated in BE, suggesting the involvement of the gastrin-CCK2R pathway in progression. In the L2-IL-1β mouse model, Barrett's-like esophagus arises from the gastric cardia. Therefore, we aimed to analyze the effect of hypergastrinemia on CCK2R+ progenitor cells in L2-IL-1β mice.

Design

L2-IL-1β mice were mated with hypergastrinemic (INS-GAS) mice or treated with PPIs to examine the effect of hypergastrinemia in BE progression. CCK2R-CreERT crossed with L2-IL-1β mice were used to analyze the lineage progenitor potential of CCK2R+ cells. Cardia glands were cultured in vitro, and the effect of gastrin treatment analyzed. L2-IL-1β mice were treated with a CCK2R antagonist YF476 as a potential chemopreventive drug.

Results

Hypergastrinemia resulted in increased proliferation and expansion of Barrett's-like esophagus. Lineage tracing experiments revealed that CCK2R+ cells are long-lived progenitors that can give rise to such lesions under chronic inflammation. Gastrin stimulated organoid growth in cardia culture, while CCK2R inhibition prevented Barrett's-like esophagus and dysplasia.

Conclusions

Our data suggest a progression model for BE to EAC in which CCK2R+ progenitor cells, stimulated by hypergastrinemia, proliferate to give rise to metaplasia and dysplasia. Hypergastrinemia can result from PPI use, and the effects of hypergastrinemia in human BE should be studied further.

Insights Into the Pathophysiology of Esophageal Adenocarcinoma

Although researchers have identified genetic alterations that contribute to development of esophageal adenocarcinoma, we know little about features of patients or environmental factors that mediate progression of chronic acid biliary reflux to Barrett's esophagus and cancer. Increasing our understanding of the mechanisms by which normal squamous epithelium progresses to early-stage invasive cancer will help formulate rational surveillance guidelines and allow us to divest resources away from patients at low risk of malignancy. We review the cellular and genetic alterations that occur during progression of Barrett's esophagus, based on findings from clinical studies and mouse models of disease. We review the features of the luminal and mucosal microenvironment of Barrett's esophagus that promote, in a small proportion of patients, development of esophageal adenocarcinoma. Markers of clonal evolution can be used to determine patient risk for cancer and set surveillance intervals.

Study of Gender Differences in Proton Pump Inhibitor Dose Requirements for GERD: A Double-Blind Randomized Trial

GOALS

To determine the proportion of patients with gastroesophageal reflux disease who are on proton pump inhibitors (PPIs) who could reduce their prior dosage by half, and identify predictors of successful step-down.

BACKGROUND

Appropriate hypergastrinemia results from gastric acid inhibition. A gender difference in fasting gastrin with higher levels among women than among men on long-term PPI therapy has been demonstrated.

STUDY

Patients with endoscopically verified erosive esophagitis on long-term PPI therapy were randomized double blindly to step down their dose by half or continue with the same dose for 8 weeks. Fasting gastrin levels were measured before and after treatment. The primary endpoint was successful step-down throughout the study period.

RESULTS

Overall, 100 patients were randomized, 49 (24 females) to continue with the same dose as before and 51 (25 females) to step down. Female patients had higher gastrin levels compared with male patients: 78 pg/mL (IQR, 50 to 99) versus 50 pg/mL (IQR, 36 to 74) (P=0.007). Among those randomized to the step-down intervention only 3/25 (12%) women failed to complete the 2 months of lower-dose therapy versus 9/25 (36%) men (P=0.09). Female gender (P=0.048) was the strongest predictor for successful step-down (odds ratio=1.27; 95% CI, 1.01-1.60). The chance of failing to maintain symptom control was twice as high in the reduction group (24%) as compared with the control group (13%) (P=0.2).

CONCLUSIONS

Female patients on long-term PPI therapy were 3 times more likely to tolerate half of their prior dose. Female gender had higher probability for successful step-down. These results indicate that women with gastroesophageal reflux disease might manage with lower doses of PPIs as compared with men.European Clinical Trial Database (https://eudract.ema.europa.eu/), number 2013-002067-26.

Proton Pump Inhibitors Do Not Reduce the Risk of Esophageal Adenocarcinoma in Patients with Barrett's Esophagus: A Systematic Review and Meta-Analysis

Objectives

Proton pump inhibitors (PPIs) have been used for treatment of Barrett's esophagus (BE) for many years. However, the connection between PPIs and esophageal adenocarcinoma (EAC) in patients with BE has still been controversial. The current systematic review and meta-analysis was designed to evaluate the association between PPIs and the risk of EAC or high-grade dysplasia (HGD) in patients with BE.

Methods

A systematic literature search of studies reporting the association between PPIs and the risk of EAC and/or HGD in patients with BE was conducted in PubMed, Embase, Web of Science and the Cochrane Library. Next, literature was screened using previously established criteria and relevant data were extracted from included studies. Finally, the software program Review Manage 5.2 was applied to aggregate data and analyze the results.

Results

Nine observational studies, comprising five cohort and four case-control studies (including a total of 5712 patients with BE), were identified. Upon meta-analysis, PPIs were found to have no association with the risk of EAC and/or HGD in patients with BE (unadjusted OR 0.43, 95% CI 0.17–1.08). Analysis for duration response relationship revealed no significant trend toward protection against EAC or HGD with PPIs usage for >2~3 years (one study using 7-year cutoff) when compared to usage for shorter time periods (PPIs usage >2~3 years vs. <2~3 years: OR 0.91 (95% CI 0.25–3.31) vs. 0.91 (0.40–2.07)).There also was considerable heterogeneity between studies.

Conclusion

No dysplasia- or cancer-protective effects of PPIs usage in patients with BE were identified by our analysis. Therefore, we conclude that clinicians who discuss the potential chemopreventive effects of PPIs with their patients, should be aware that such an effect, if exists, has not been proven with statistical significance.

Cholecystokinin expression in tumors: biogenetic and diagnostic implications

Cholecystokinin (CCK) is a classic gut hormone. CCK is also a complex system of peptides expressed in several molecular forms in enteroendocrine I cells, in cerebral and peripheral neurons, in cardiac myocytes and spermatozoa. CCK gene expression has now been found at protein or peptide level in different neuroendocrine tumors; cerebral gliomas and astrocytomas and specific pediatric tumors. Tumor hypersecretion of CCK was recently reported in a patient with a metastatic islet cell tumor and hypercholecystokininemia resulting in a novel tumor syndrome, the cholecystokininoma syndrome. This review presents an overview of the cell-specific biogenesis of CCK peptides, and a description of the CCK expression in tumors and of the cholecystokininoma syndrome. Finally, assays for the diagnosis of CCK-producing tumors are reviewed.

Oesophageal adenocarcinoma and gastric cancer: should we mind the gap?

Over recent decades we have witnessed a shift in the anatomical distribution of gastric cancer (GC), which increasingly originates from the proximal stomach near the junction with the oesophagus. In parallel, there has been a dramatic rise in the incidence of oesophageal adenocarcinoma (OAC) in the lower oesophagus, which is associated with antecedent Barrett oesophagus (BO). In this context, there has been uncertainty regarding the characterization of adenocarcinomas spanning the area from the lower oesophagus to the distal stomach. Most relevant to this discussion is the distinction, if any, between OAC and intestinal-type GC of the proximal stomach. It is therefore timely to review our current understanding of OAC and intestinal-type GC, integrating advances from cell-of-origin studies and comprehensive genomic alteration analyses, ultimately enabling better insight into the relationship between these two cancers.

Safety of proton pump inhibitors and risk of gastric cancers: review of literature and pathophysiological mechanisms

INTRODUCTION

Despite being an overall safe drug, several long-term adverse effects are associated with proton pump inhibitors (PPIs). The link between PPI use and gastric neuroendocrine tumors (NETs), gastric adenocarcinomas and Barrett's esophagus progression gastric cancers has been investigated due to PPI-induced hypergastrinemia.

AREAS COVERED

The pathophysiological mechanisms underlying PPI exposure and gastric NETs, gastric adenocarcinomas and Barrett's esophagus progression are discussed. The quality of randomized control studies, cohort studies and case reports investigating the link between gastric cancers and PPIs are examined. Recommendations for clinicians are provided.

EXPERT OPINION

PPIs cause a hypergastrinemic state, increasing enterochromaffin-like cell dysplasia and risk of gastric NET development, increasing gastritis severity in the context of Helicobacter pylori infection, and progression of carcinogenesis in a certain predisposed subset of Barrett's esophagus patients. There are case reports of PPI-induced gastric NETs and adenocarcinomas as consequences of these effects. In pernicious anemia and chronic gastritis, clinicians should be aware of potential increased risk of gastric NET development with chronic PPI use in these patients. Eradication status of H. pylori prior to commencing long-term PPI therapy should be established to reduce the risk of severe atrophic gastritis and development of gastric dysplasia.

Chemoprevention in Barrett's Esophagus: Current Status

Chemoprevention in Barrett's esophagus is currently applied only in research settings. Identifying pathways that can be targeted by safe, pharmaceutical or natural compounds is key to expanding the scope of chemoprevention. Defining meaningful surrogate markers of cancer progression is critical to test the efficacy of chemopreventive approaches. Combinatorial chemoprevention that targets multiple components of the same pathway or parallel pathways could reduce the risk and improve the efficacy of chemoprevention. Here we discuss the role of chemoprevention as an independent or an adjuvant management option in BE-associated esophageal adenocarcinoma.

Biomarkers in Barrett's Esophagus: Role in Diagnosis, Risk Stratification, and Prediction of Response to Therapy

Esophageal adenocarcinoma (EAC) has increased dramatically in the past 3 decades, making its precursor lesion Barrett's esophagus (BE) an important clinical problem. Effective interventions are available, but overall outcomes remain unchanged. Most of the BE population remains undiagnosed; most EACs are diagnosed late, and most BE patients will never progress to cancer. These epidemiologic factors make upper endoscopy an inefficient and ineffective strategy for BE diagnosis and risk stratification. In the current review, biomarkers for diagnosis, risk stratification, and predictors of response to therapy in BE are discussed.

The Effect of Proton Pump Inhibitors on Barrett's Esophagus

Proton pump inhibitors (PPIs) may protect against carcinogenesis in Barrett's esophagus because they eliminate the chronic esophageal inflammation of reflux esophagitis, and because they decrease esophageal exposure to acid, which can cause cancer-promoting DNA damage and increase proliferation in Barrett's metaplasia. Most clinical studies of PPIs and cancer development in Barrett's esophagus have found a cancer-protective effect for these drugs, although there are some contradictory data. Chemoprevention of dysplasia and cancer in Barrett's esophagus with PPIs appears to be cost-effective, and the indirect evidence supporting a cancer-protective role for PPIs is strong enough to warrant PPI treatment of virtually all patients with Barrett's esophagus.

Role of proton pump inhibitor on esophageal carcinogenesis and pancreatic acinar cell metaplasia development: an experimental in vivo study

Chronic gastro-duodenal reflux in the esophagus is a major risk for intestinal metaplasia and Barrett’s adenocarcinoma. A role for chronic use of proton pump inhibitor (PPI) in the increased incidence of esophageal adenocarcinoma in Western countries has been previously suggested. The aim of this work was to study the effect of chronic administration of omeprazole (a proton pump inhibitor) per os in a model of reflux induced esophageal carcinogenesis. One week after esophago-gastro-jejunostomy, 115 Sprague-Dawley rats were randomized to receive 10 mg/Kg per day of omeprazole or placebo, 5 days per week. The esophago-gastric specimens were collected 28±2 weeks after randomization and analyzed in a blinded fashion. Mortality and esophageal metaplasia rates did not differ between the two groups (p = 0.99 for mortality, p = 0.36 for intestinal metaplasia and p = 0.66 for multi-layered epithelium). Gastric pancreatic acinar cell metaplasia (PACM) was more frequently observed in PPI-treated rats (p = 0.003). Severe ulcer lesions significantly prevailed in the placebo group (p = 0.03). Locally invasive esophageal epithelial neoplasia were observed in 23/39 PPI-treated versus 14/42 placebo-animals (p = 0.03). In conclusion, chronic omeprazole treatment improved the healing of esophageal ulcerative lesions. Locally invasive neoplastic lesions and PACM prevailed among PPI-treated animals. However, neither an effect on the overall mortality nor on the incidence of pre-neoplastic lesions was observed in this work.

Do glycine-extended hormone precursors have clinical significance?

Half of the known peptide hormones are C-terminally amidated. Subsequent biogenesis studies have shown that the immediate precursor is a glycine-extended peptide. The clinical interest in glycine-extended hormones began in 1994, when it was suggested that glycine-extended gastrin stimulated cancer cell growth. Accompanying findings of gastrin gene expression in common cancers spurred the interest. The interest is now accompanied by skepticism, which is due to failure to demonstrate truly specific receptors for glycine-extended peptides and failure to demonstrate separate physiological and clinical effects of glycine-extended precursors for most other amidated hormones than gastrin and cholecystokinin (CCK). The idea of glycine-extended peptides as independent messengers was interesting. But clinical science has to move ahead from ideas that cannot be supported at key points after decades of research.

Evaluation of a 4-protein serum biomarker panel-biglycan, annexin-A6, myeloperoxidase, and protein S100-A9 (B-AMP)-for the detection of esophageal adenocarcinoma

BACKGROUND

Esophageal adenocarcinoma (EAC) is associated with a dismal prognosis. The identification of cancer biomarkers can advance the possibility for early detection and better monitoring of tumor progression and/or response to therapy. The authors present results from the development of a serum-based, 4-protein (biglycan, myeloperoxidase, annexin-A6, and protein S100-A9) biomarker panel for EAC.

METHODS

A vertically integrated, proteomics-based biomarker discovery approach was used to identify candidate serum biomarkers for the detection of EAC. Liquid chromatography-tandem mass spectrometry analysis was performed on formalin-fixed, paraffin-embedded tissue samples that were collected from across the Barrett esophagus (BE)-EAC disease spectrum. The mass spectrometry-based spectral count data were used to guide the selection of candidate serum biomarkers. Then, the serum enzyme-linked immunosorbent assay data were validated in an independent cohort and were used to develop a multiparametric risk-assessment model to predict the presence of disease.

RESULTS

With a minimum threshold of 10 spectral counts, 351 proteins were identified as differentially abundant along the spectrum of Barrett esophagus, high-grade dysplasia, and EAC (P<.05). Eleven proteins from this data set were then tested using enzyme-linked immunosorbent assays in serum samples, of which 5 proteins were significantly elevated in abundance among patients who had EAC compared with normal controls, which mirrored trends across the disease spectrum present in the tissue data. By using serum data, a Bayesian rule-learning predictive model with 4 biomarkers was developed to accurately classify disease class; the cross-validation results for the merged data set yielded accuracy of 87% and an area under the receiver operating characteristic curve of 93%.

CONCLUSIONS

Serum biomarkers hold significant promise for the early, noninvasive detection of EAC.

Proton pump inhibitor use may not prevent high-grade dysplasia and oesophageal adenocarcinoma in Barrett's oesophagus: a nationwide study of 9883 patients

BACKGROUND

Proton pump inhibitors (PPI) may potentially modify and decrease the risk for development of oesophageal adenocarcinoma in Barrett's oesophagus (BO).

AIM

To investigate if the intensity and adherence of PPI use among all patients with BO in Denmark affected the risk of oesophageal adenocarcinoma.

METHODS

We performed a nationwide case-control study in Denmark among 9883 patients with a new diagnosis of BO. All incident oesophageal adenocarcinomas and high-grade dysplasias were identified, and risk ratios were estimated on the basis of prior use of PPIs. Sex- and age-matched BO patients without dysplasia or malignancies in a 10:1 ratio were used for comparison. Conditional logistic regression was used for analysis, adjusting for low-grade dysplasia, gender and medication.

RESULTS

We identified 140 cases with incident oesophageal adenocarcinomas and/or high-grade dysplasia, with a median follow-up time of 10.2 years. The relative risk of oesophageal adenocarcinoma or high-grade dysplasia was 2.2 (0.7-6.7) and 3.4 (95% CI: 1.1-10.5) in long-term low- and high-adherence PPI users respectively.

CONCLUSIONS

No cancer-protective effects from PPI's were seen. In fact, high-adherence and long-term use of PPI were associated with a significantly increased risk of adenocarcinoma or high-grade dysplasia. This could partly be due to confounding by indication or a true negative effect from PPIs. Until the results from future studies hopefully can elucidate the association further, continuous PPI therapy should be directed at symptom control and additional modalities considered as aid or replacement.

The effects of long-term therapy with proton pump inhibitors on meal stimulated gastrin

BACKGROUND

Dyspepsia develops in healthy volunteers after withdrawal of proton-pump inhibitors. This phenomenon, attributed to rebound acid hypersecretion, is thought to be mediated by reflex hypergastrinemia.

AIMS

To measure fasting and postprandial gastrin in patients on long-term proton-pump inhibitor treatment and correlate gastrin levels with the duration of treatment and other potential predictors.

METHODS

In this cross sectional study patients, with erosive esophagitis, on long-term proton-pump inhibitor treatment and healthy controls underwent gastrin measurements at baseline and four times following a meal and Helicobacter pylori status was determined.

RESULTS

A total of 100 patients and 50 controls were studied. Pre- and postprandial gastrin levels were higher in patients (p<0.001). No significant correlation was found between the area under the gastrin-curve and the treatment duration. Female patients had significantly higher gastrin levels than males pre- and postprandial, whereas such differences was not found in the control group. Female gender was the only independent predictor of s-gastrin levels (OR 2.50 compared to males, 95% CI: 1.08-5.76, p=0.032) in the patient group.

CONCLUSION

Gastrin values were higher in patients compared to controls. There was no correlation between gastrin levels and treatment duration. Female patients had significantly higher gastrin values than males.

Rebound effect of modern drugs: serious adverse event unknown by health professionals

OBJECTIVE

Supported in the Hippocratic aphorism primum non nocere, the bioethical principle of non-maleficence pray that the medical act cause the least damage or injury to the health of the patient, leaving it to the doctor to assess the risks of a particular therapy through knowledge of possible adverse events of drugs. Among these, the rebound effect represents a common side effect to numerous classes of modern drugs, may cause serious and fatal disorders in patients. This review aims to clarify the health professionals on clinical and epidemiological aspects of rebound phenomenon.

METHODS

A qualitative, exploratory and bibliographic review was held in the PubMed database using the keywords 'rebound', 'withdrawal', 'paradoxical', 'acetylsalicylic acid', 'anti-inflammatory', 'bronchodilator', 'antidepressant', 'statin', 'proton pump inhibitor' and 'bisphosphonate'.

RESULTS

The rebound effect occurs after discontinuation of numerous classes of drugs that act contrary to the disease disorders, exacerbating them at levels above those prior to treatment. Regardless of the disease, the drug and duration of treatment, the phenomenon manifests itself in a small proportion of susceptible individuals. However, it may cause serious and fatal adverse events should be considered a public health problem in view of the enormous consumption of drugs by population.

CONCLUSION

Bringing together a growing and unquestionable body of evidence, the physician needs to have knowledge of the consequences of the rebound effect and how to minimize it, increasing safety in the management of modern drugs. On the other hand, this rebound can be used in a curative way, broadening the spectrum of the modern therapeutics.

Role of gastrin-peptides in Barrett's and colorectal carcinogenesis

Gastrin is the main hormone responsible for the stimulation of gastric acid secretion; in addition, gastrin and its derivatives exert proliferative and antiapoptotic effects on several cell types. Gastrin synthesis and secretion are increased in certain situations, for example, when proton pump inhibitors are used. The impact of sustained hypergastrinemia is currently being investigated. In vitro experiments and animal models have shown that prolonged hypergastrinemia may be related with higher cancer rates; although, this relationship is less clear in human beings. Higher gastrin levels have been shown to cause hyperplasia of several cell types; yet, the risk for developing cancer seems to be the same in normo- and hypergastrinemic patients. Some tumors also produce their own gastrin, which can act in an autocrine manner promoting tumor growth. Certain cancers are extremely dependent on gastrin to proliferate. Initial research focused only on the effects of amidated gastrins, but there has been an interest in intermediates of gastrin in the last few decades. These intermediates aren’t biologically inactive; in fact, they may exert greater effects on proliferation and apoptosis than the completely processed forms. In certain gastrin overproduction states, they are the most abundant gastrin peptides secreted. The purpose of this review is to examine the gastrin biosynthesis process and to summarize the results from different studies evaluating the production, levels, and effects of the main forms of gastrin in different overexpression states and their possible relationship with Barrett’s and colorectal carcinogenesis.

Barrett esophagus: what a mouse model can teach us about human disease

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising in the western world and accounts for 2% of all cancer-related deaths. The precursor lesion for EAC is Barrett esophagus (BE), which is strongly associated with gastresophageal reflux disease. A major limitation to the study of EAC has been the absence of tractable and genetically modifiable preclinical models of BE. A mouse model of BE and EAC that resembles human disease could provide novel insights into the origins and molecular pathogenesis of BE. In addition, validated animal models could help stratify BE patients given the limited predictive power of current standard endoscopic measures and clinical assessment. Here, we review the findings from recently developed mouse models of BE and EAC and their impact on clinical decision making, surveillance programs and therapeutic options. The data, taken together, suggest potential origins of BE from the gastric cardia, a role of bile acid and hypergatrinemia for carcinogenesis, a growing importance for columnar-like epithelium and a critical role for Notch signaling.

Rebound acid hypersecretion after withdrawal of gastric acid suppressing drugs: new evidence of similitude

BACKGROUND

Homeopathy is based on the principle of similitude (similia similibus curentur) using medicines that cause effects similar to the symptoms of disease in order to stimulate the reaction of the organism. Such vital, homeostatic or paradoxical reaction of the organism is closely related to rebound effect of drugs.

METHOD

Review of the literature concerning the rebound effects of drugs used to suppress gastric acidity, particularly proton pump inhibitors (PPIs).

RESULTS

The mechanism of action of these effects is discussed. Rebound in terms of clinical symptoms and physiological effects occur in about 40% of people taking PPIs, their timing depends on the half-life of the drug and the adaptation period of the physiological mechanisms involved. The wide use of PPIs may be linked to the rising incidence of carcinoid tumours.

CONCLUSIONS

These findings support Hahnemann's concept of secondary action of drugs. We are developing a homeopathic materia medica and repertory of modern drugs on the basis of reported rebound effects.

Role of acid suppression in the development and progression of dysplasia in patients with Barrett's esophagus

Barrett's esophagus (BE) usually develops in patients with gastroesophageal reflux disease and therefore it has been suggested that esophageal acid exposure plays an import role in the initiation of BE and its progression towards esophageal adenocarcinoma (EAC). The mechanisms whereby acid exposure causes BE are not completely revealed and the potential role of esophageal acid exposure in carcinogenesis is unclear as well. Since acid exposure is thought to play an important role in the progression of BE, therapies aimed at preventing the development of EAC have primarily focused on pharmacological and surgical acid suppression. In clinical practice, acid suppression is effective in relieving reflux symptoms and decreases esophageal acid exposure in most patients. However, in some individuals, pathological acid exposure persists and these patients continue to be at risk for developing dysplasia or EAC. To date, published trials suggest that acid suppression is able to prevent the development and progression of dysplasia in patients with BE, but definite and compelling proof is still lacking. This article reviews the mechanisms of acid-induced carcinogenesis in BE and the role of acid suppression in the prevention of neoplastic progression.

Targeting gastrin for the treatment of gastric acid related disorders and pancreatic cancer

Gastrin, acting through peripheral cholecystokinin (CCK) 2 receptors, is a major hormonal regulator of gastric acid secretion. The effects of gastrin on acid secretion occur both acutely and chronically because gastrin directly stimulates gastric acid secretion and also exerts trophic effects on the enterochromaffin-like and parietal cells that together constitute the acid secretory apparatus of the stomach. Several antagonists that target the CCK2 receptor have been identified and investigated for the treatment of gastroesophageal reflux disease and pancreatic cancer. In this paper, we discuss the contribution of gastrin to these disease pathologies and the data generated to date from clinical studies investigating CCK2 receptor antagonists.

Correlation between serum gastrin and cellular proliferation in Barrett's esophagus

BACKGROUND

Patients with Barrett's esophagus (BE) are commonly treated with proton-pump inhibitors (PPIs) to minimize the exposure of esophageal mucosa to stomach acid. However, the use of these medications can lead to significant hypergastrinemia in a subset of patients, which is concerning due to the known tumorigenic and proliferative effects of gastrin. The present pilot study aims to investigate a potential correlation between serum gastrin and cellular proliferation in BE.

METHODS

We performed a cross-sectional analysis of patients with nondysplastic BE on PPI therapy. Fasting serum gastrin was measured on the same day as esophageal biopsies were obtained. These biopsies were then stained with Ki-67 nuclear antibody. Pearson's correlation coefficient was calculated to assess the relationship between Ki-67 index and ln(gastrin).

RESULTS

A total of 10 patients were included in the study. The mean age was 62.6 (±8.4) years and 5 patients were male. The median serum gastrin level was 45.2 pM (interquartile range [IQR] 33-113) and the median Ki-67 index was 49.6% (IQR 23-64). We found a statistically significant positive correlation between Ki-67 index and ln(gastrin) (r = 0.64; p = 0.05).

CONCLUSIONS

In nondysplastic BE patients on PPI therapy, serum gastrin levels were significantly correlated with cellular proliferation. These pilot data lend support to a potential causal effect of gastrin on neoplastic progression in BE. Longitudinal studies of patients with BE are needed to determine whether hypergastrinemia is a risk factor for the development of dysplasia and adenocarcinoma or could be used as a biomarker for disease progression.

Barrett's esophagus, esophageal and esophagogastric junction adenocarcinomas: the role of diet

Identification of modifiable risk factors is an attractive approach to primary prevention of esophageal adenocarcinoma (EAC) and esophagogastric junction adenocarcinoma (EGJAC). We conducted a review of the literature to investigate the association between specific dietary components and the risk of Barrett’s esophagus (BE), EAC and EGJAC, supposing diet might be a risk factor for these tumors. Consumption of meat and high-fat meals has been found positively associated with EAC and EGJAC. An inverse association with increased intake of fruit, vegetables and antioxidants has been reported but this association was not consistent across all studies reviewed. Few studies have examined the association between diet and BE. Additional research is needed to confirm the aforementioned association and clarify the mechanisms by which dietary components affect the risk of developing EAC and EGJAC. Future studies could advance our knowledge by emphasizing prospective designs to reduce recall bias, by using validated dietary intake questionnaires and biological measures and by considering important confounders such as gastro-esophageal reflux disease (GERD) symptoms, tobacco and alcohol use, biometrics, physical activity, and socioeconomic factors.

Adverse effects of proton pump inhibitor drugs: clues and conclusions

PURPOSE OF REVIEW

To review evidence relating to the strength of associations that have appeared in largely observational studies, between high-dose or long-term use of proton pump inhibitor drugs and certain possibly attributable side-effects, which emerge from studies confounded by other variables. In retrospective studies not designed to assess safety, evidence of causality is generally lacking.

RECENT FINDINGS

The associations of fractures of hip, wrist, forearm and other sites appear weak and only slightly higher than the risks in control populations matched for age. They may increase with drug exposure, but probably do so only in individuals in whom other risk factors are also operational (smoking, alcohol, poor nutrition, steroids, etc.). The risks of Clostridium difficile colitis, other enteric infections, small bowel bacterial overgrowth and possibly spontaneous bacterial peritonitis also appear increased. Impaired gastric secretion may adversely affect the absorption of various nutrients, but their clinical impact is ill defined. Potentially more important are the consequences of hypergastrinemia, including rebound hypersecretion of acid, and possible development of various cancers, including carcinoid tumors. Effects of other drugs, including clopidogrel, on metabolism are reviewed, but clouded by uncertainties.

SUMMARY

The safety of long-term PPI administration needs serious prospective study.