Evidence that proton-pump inhibitor therapy induces the symptoms it is used to treat

Marginal Ulcer Incidence and the Population of Gastrin Producing G cells Retained in the Gastric Pouch after Roux-en-Y Gastric Bypass: Is There a Relationship?

INTRODUCTION

Marginal ulcers are the most prevalent endoscopic abnormality after RYGB. The etiology is still poorly understood; however, an increase in acid secretion has been strongly implicated as a causal agent. Although gastrin is the greatest stimulant of acid secretion, to date, the presence of gastrin producing G cells retained in the gastric pouch, related to the occurrence of marginal ulcers, has not been evaluated.

OBJECTIVE

Evaluate the density of G cells and parietal cells in the gastric pouch of RYGB patients with a diagnosis of marginal ulcer on the post-op EGD.

METHOD

We retrospectively evaluated 1104 gastric bypasses performed between 2010 and 2020. Patients with marginal ulcer who met the inclusion criteria and controls were selected from this same population. Endoscopic gastric pouch biopsies were evaluated using immunohistochemical study and HE staining to assess G cell and parietal cell density.

RESULTS

In total, 572 (51.8%) of the patients performed endoscopic follow-up after RYGB. The incidence of marginal ulcer was 23/572 (4%), and 3 patients required revision surgery due to a recalcitrant ulcer. The mean time for ulcer identification was 24.3 months (2-62). G cell count per high-power field (× 400) was statistically higher in the ulcer group (p < 0.05). There was no statistical difference in parietal cell density between groups (p 0.251).

CONCLUSION

Patients with a marginal ulcer after gastric bypass present a higher density of gastrin-producing G cells retained in the gastric pouch.

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.

Real-world evidence with magnetic sphincter augmentation for gastroesophageal reflux disease: a scoping review

Background

The burden of gastroesophageal reflux disease (GERD) is high, with up to 30% of the Western population reporting reflux-related symptoms with or without hiatal hernia. Magnetic sphincter augmentation (MSA) is a standardized laparoscopic procedure for patients who are dissatisfied with medical therapy and for those with early-stage disease who would not usually be considered ideal candidates for fundoplication. The MSA device is manufactured in different sizes and is designed to augment the physiologic barrier to reflux by magnetic force.

Methods

An extensive scoping review was performed to provide a map of current evidence with respect to MSA, to identify gaps in knowledge, and to make recommendations for future research. All the authors contributed to the literature search in PubMed and Web of Science and contributed to summarizing the evidence.

Results

Magnetic sphincter augmentation, especially in combination with crural repair, is effective in reducing GERD symptoms, proton pump inhibitor use, and esophageal acid exposure, and in improving patients’ quality of life. Safety issues such as device erosion or migration have been rare and not associated with mortality. The MSA device can be removed laparoscopically if necessary, thereby preserving the option of fundoplication or other therapies in the future. Contraindication to scanning in high-power Tesla magnetic resonance systems remains a potential limitation of the MSA procedure. High-resolution manometry and functional lumen imaging probes appear to be promising tools to predict procedural outcomes by improving reflux control and reducing the incidence of dysphagia.

Conclusion

A consensus on acquisition and interpretation of high-resolution manometry and impedance planimetry data is needed to gain better understanding of physiology, to improve patient selection, and to pave the way for a personalized surgical approach in antireflux surgery.

[Updating in prescription of proton pump inhibitors. What to do and what not to do]

INTRODUCTION

Proton pump inhibitors (PPIs) are the most prescribed pharmacological subgroup of the National Health System and their use has been related to possible potentially serious adverse effects.

OBJECTIVE

To review the current indications for treatment with PPIs as well as the data related to their safety, in order to promote their adecuate use.

MATERIAL AND METHODS

A review of the literature focused on the following topics has been carried out: a) molecules and mechanism of action; b) current indications for treatment and adherence to them; c) adverse effects related to its use; d) drug interactions; e) alternatives in deprescription.

RESULTS

The current indications have not changed substantially in recent years and are well established, however, there is a high percentage of inappropriate prescription, mainly in individuals with low or no risk.

CONCLUSIONS

PPIs are safe drugs and generally well tolerated and their benefits are higher than possible adverse effects. Adhering to evidence-based recommendations represents the only rational approach to safe and effective therapy.

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.

Problems Associated with Deprescribing of Proton Pump Inhibitors

Proton pump inhibitors (PPIs) are recommended as a first-line treatment for gastroesophageal reflux disease (GERD) and other acid related disorders. In recent years, concerns have been raised about the increasing prevalence of patients on long-term PPI therapy and inappropriate PPI use. It is well known that short-term PPI therapy is generally well tolerated and safe; however, their extensive long-term use is a major global issue. One of these long-standing concerns is PPI-induced gastrin elevation secondary to hypoacidity. Hypergastrinemia is believed to play a role in rebound hyperacidity when PPIs are discontinued resulting in induced dyspeptic symptoms that might result in the reinstitution of therapy. Gastrin exerts tropic effects in the stomach, especially on enterochromaffin-like (ECL) cells, and concerns have also been raised regarding the potential progression to dysplasia or tumor formation following long-term therapy. It is well known that a substantial number of patients on long-term PPI therapy can discontinue PPIs without recurrence of symptoms in deprescribing trials. What is unknown is how sustainable deprescribing should be undertaken in practice and how effective it is in terms of reducing long-term outcomes like adverse drug events, morbidity and mortality. Moreover, there is no clear consensus on when and how deprescribing strategies should be attempted in practice. This review sought to summarize the harms and benefits of long-term PPI therapy with special focus on gastrin elevation and its relation to deprescribing studies and future interventions that may improve PPI use.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

Magnetic sphincter augmentation (MSA) in patients with hiatal hernia: clinical outcome and patterns of recurrence

Introduction

Magnetic sphincter augmentation (MSA) is an effective treatment for patients with gastroesophageal reflux disease. In early studies, patients with a hiatal hernia (HH) ≥ 3 cm were excluded from consideration for implantation and initially the FDA considered its use as “precautionary” in this context. This early approach has led to an attitude of hesitance among some surgeons to offer this therapy to patients with HH. This study was designed to evaluate the impact of HH status on the outcome of MSA and to report the rate of HH recurrence after MSA.

Methods and procedures

This is a retrospective review of prospectively collected data of patients who underwent MSA between June 2013 and August 2017. Baseline clinical and objective data were collected. Patients were divided into four groups based on HH status: no HH, small HH (< 3 cm), large HH (≥ 3 cm), and paraesophageal hernia (PEH). Patient satisfaction, GERD–HRQL and RSI data, freedom from PPI, need for postoperative dilation, length of hospitalization, 90-day readmission rate, need for device removal, and HH recurrence was compared between groups.

Results

There were 350 patients [60% female, mean (SD) age: 53.5 (13.8)] who underwent MSA. There were 65 (18.6%) with no HH, 205 (58.6%) with small HH (< 3 cm), 58 (16.6%) with large HH (≥ 3 cm) and 22 (6.2%) with PEH. At a mean follow-up of 13.6 (10.4) months, the rate of outcome satisfaction was similar between the groups (86%, 87.9%, 92.2% and 93.8%, p = 0.72). This was also true for GERD–HRQL total score clinical improvement (79.1%, 77.8%, 82% and 87.5%, p = 0.77). The rate of postoperative dysphagia (p = 0.33) and freedom from PPIs (p = 0.96) were similar among the four groups. Duration of hospitalization was higher among those with a large HH or PEH, and only PEH patients had a higher 90-day readmission rate (p = 0.0004). There was no difference between the need for dilation among groups (p = 0.13). The need for device removal (5% overall) was similar between the four groups (p = 0.28). HH recurrence was 10% in all groups combined, and only 7 of 240 (2.9%) patients required reoperation; the majority of these patients underwent a minimal dissection approach (no hernia repair) at the index operation. The incidence of recurrent HH increased in direct correlation with the preoperative HH size (0%, 10.1%, 16.6 and 20%, p = 0.032).

Conclusion

In the largest series of MSA implantation, we demonstrate that the excellent outcomes and high degree of satisfaction after MSA are independent of the presence or size of HH. Despite higher rates of hernia recurrence in large HH and PEH patients, the rates of postoperative endoscopic intervention, and device removal is similar to those with no or small HH. The minimal dissection approach to MSA should be abandoned.

Artepillin C, drupanin, aromadendrin-4'-O-methyl-ether and kaempferide from Brazilian green propolis promote gastroprotective action by diversified mode of action

ETHOPHARMACOLOGICAL RELEVANCE

The propolis is extensively used in folk medicine in natura or to prepare pharmaceutical formulations since ancient time to improve health or prevent diseases, among them gastrointestinal disorders. Aiming to contribute in the scientific validation about the popular use of Brazilian Green propolis (BGP) against gastritis and gastric ulcer, this work evaluated the antiulcer potential of isolated compounds from BGP, three prenylated p-coumaric acid derivatives and two flavonoids, respectively named: 3,5 diprenyl-4-hydroxycinnamic acid (artepillin C) (1), 3-prenyl-4-dihydroxycinnamoiloxy cinnamic acid (baccharin) (2), 3-prenyl-4-hydroxycinnamic acid (drupanin) (3), aromadendrin-4'-O-methyl-ether (4) and kaempferide (5).

MATERIAL AND METHODS

The compounds were characterized by nuclear magnetic resonance and mass spectrometry. Their gastroprotective effects were evaluated against ethanol/HCl- and indomethacin-induced ulcer in mice. Further, histological, histochemical, oxidative and inflammatory parameters were analyzed at ulcerated tissue. Acid antisecretory activities also were also assessed.

RESULTS

Compound 2 did not reduce the ethanol/HCl- induced ulcer at 30 mg/kg (p.o), whereas the minimum oral gastroprotective doses of 1, 3, 4 and 5 were 0.3, 0.3, 3 and 3 mg/kg, respectively. Besides, these compounds prevented ethanol/HCl-induced ulcer by intraperitoneal route, as well as indomethacin-induced ulcer by oral route. The gastroprotection was accompanied by normalization of superoxide dismutase, catalase and glutathione-S-transferase activities and reduction in myeloperoxidase activity. Moreover, the compounds 4 and 5 increased the gastric mucin content and 1 reduced TNF amount. Furthermore, 1, 3, 4 and 5 decreased volume, pH, total acidity and pepsin activity of the gastric juice from rats.

CONCLUSIONS

Together, our findings showed a diversified mode of action elicited by 1, 3, 4 and 5 on the gastroprotection and contribute to explain the anti-ulcer activity reported for BGP.

Proton pump inhibitors and the risk of severe adverse events - A cardiovascular bombshell?

Proton pump inhibitors are currently one of the most prescribed pharmacological classes in developed countries, given their effectiveness and safety profile, which has until now been considered favorable. However, in recent years, several papers have been published that associate prolonged use of these drugs with a wide range of adverse effects, posing doubts about their safety. Among the adverse effects described is an increased risk of cardiovascular events. This relationship was first described in subjects after acute coronary syndrome due to the interference of proton pump inhibitors in the cytochrome P450 2C19 and the conversion of clopidogrel to its active metabolite. More recent studies have also reported this relationship with the use of antiplatelet agents that do not depend on cytochrome P450 2C19 activation. The proposed mechanism is inhibition of dimethylarginine dimethylaminohydrolase, a physiological inhibitor of asymmetric dimethylarginine, which increases plasma concentrations of the latter enzyme, leading to lower levels of nitric oxide. By reviewing in this article the relationship between the use of proton pump inhibitors and increased risk of cardiovascular and cerebrovascular events, the authors aim to alert the medical community to the potentially harmful effects of these drugs, and recommend the setting of a moratorium on their prolonged use.

Healing and Antisecretory Effects of Aqueous Extract of Eremomastax speciosa (Acanthaceae) on Unhealed Gastric Ulcers

OBJECTIVE

This work investigated the healing and antisecretory effects of the aqueous extract of Eremomastax speciosa on "unhealed gastric ulcers" associated with gastric acid hypersecretion.

MATERIALS AND METHODS

"Unhealed gastric ulcers" were induced using indomethacin following the establishment of acetic-acid-induced chronic gastric ulcers. The extract (200 and 400 mg/kg, per os) was administered concomitantly with indomethacin (1 mg/kg, subcutaneously). The effects of the extract on both basal and histamine-stimulated gastric acid secretion were determined. Mucus secretion and oxidative stress parameters were measured, and histological assessment of ulcer healing was carried out.

RESULTS

The extract significantly promoted the healing process in rats subjected to "unhealed gastric ulcers" (82.4-88.5% healing rates). Treatment with the extract significantly reduced the basal (25.95-49.51% reduction rates) and histamine-stimulated (24.25-47.41%) acid secretions. The healing effect of the extract was associated with a significant (p < 0.05) increase of mucus secretion and concentrations of antioxidant enzymes compared with the controls. The extract at the highest dose showed normalization of the mucosa, without glandular destruction and with the disappearance of fibrosis and lymphocyte infiltration.

CONCLUSION

The abilities of the extract to increase mucus secretion, to reinforce antioxidant status, and to inhibit acid secretion would be some of the mechanisms by which this extract would accelerate the healing process in "unhealed gastric ulcers."

Randomised trial of the effect of a gastrin/CCK2 receptor antagonist on esomeprazole-induced hypergastrinaemia: evidence against rebound hyperacidity

PURPOSE

Hypergastrinaemia induced by proton pump inhibitor (PPI) therapy may cause ECL-cell and parietal-cell hyperplasia and rebound hyperacidity and dyspepsia after PPI withdrawal. The aim of the study was to assess the effect of different dosage-regimens of netazepide, a gastrin/CCK₂ receptor antagonist, on PPI-induced hypergastrinaemia and elevated chromogranin A (CgA).

METHODS

Six groups of eight healthy subjects participated in a randomised, double-blind study of esomeprazole 40 mg daily for 28 days, in combination with netazepide 1, 5 or 25 mg or placebo, daily, during the last 14 days of esomeprazole or during 14 days after treatment withdrawal. Fasting serum gastrin and plasma CgA were measured during treatment and after withdrawal, as biomarkers of acid suppression and ECL-cell activity, respectively. Dyspepsia was monitored throughout the study.

RESULTS

Esomeprazole increased gastrin and CgA. Netazepide increased gastrin, but not CgA, and inhibited dose dependently the CgA response to esomeprazole. Gastrin and CgA returned to baseline within 2-3 days of esomeprazole withdrawal; netazepide did not shorten that time. There was no rebound dyspepsia after esomeprazole withdrawal.

CONCLUSIONS

Esomeprazole and netazepide each increase gastrin, consistent with a secondary effect of gastric acid suppression, but by different mechanisms. Esomeprazole-induced hypergastrinaemia stimulates ECL cells and thereby increases CgA. Netazepide-induced hypergastrinaemia does not increase CgA, because netazepide blocks gastrin/CCK₂ receptors on ECL cells. Co-administration of netazepide 5 mg abolishes the effect of esomeprazole-induced hypergastrinaemia on ECL cells. The quick return to baseline of gastrin and CgA and absence of dyspepsia after esomeprazole withdrawal do not support the concept of rebound hyperacidity.

Acid suppressing therapy as a risk factor for Candida esophagitis

Studies were reviewed from PubMed for risk factors for the development, recurrence, prevention and therapy of Candida esophagitis, and for mechanisms induced by acid-suppressing therapy potentially influencing these factors. Documented observations included greatly increased Candida populations in the mouth, esophagus, stomach, and upper small intestine induced by acid-suppressing therapy. Among patients without HIV disease, PPI consumers more frequently had developed Candida esophagitis than did non-consumers and had also developed its recurrences more frequently. Similar phenomena associated with H2 -blocker use were less intense, and the possibility of similar phenomena in patients with HIV disease apparently had not yet been examined in spite of their high frequency of this disorder. PPI-induced elimination of the gastric acid barrier is a major mechanism leading to oro-pharyngeal and esophageal candida colonization, while PPI-induced impairment of absorption of most orally administered antifungal agents may limit the prophylactic and therapeutic success of these agents. These observations suggest potential value in limiting PPI use in populations of patients with Candida infections including esophagitis, as well as in patients at risk for their development, and also suggest that post-PPI rebound acid hypersecretion may provide additional anti-Candida benefit. Studies designed to develop the risk-benefit ratios of PPI use in these patients deserve investigation with high priority appropriate for studies in patients with HIV disease.

Gastric neuroendocrine neoplasms and proton pump inhibitors: fact or coincidence?

OBJECTIVE

Reporting on three cases of gastric neuroendocrine tumors (g-NETs) in patients taking long-term proton pump inhibitors (PPIs). These tumors are not classifiable considering current criteria. g-NETs are currently grouped as: types 1 and 2, related to hypergastrinemia due to chronic atrophic gastritis and Zollinger-Ellison syndrome respectively, and type 3, normogastrinemic and more aggressive. Although the g-NETs onset in patients taking PPIs is biologically plausible, only a few cases have been reported so far.

MATERIALS AND METHODS

From January 2005 to July 2014, 31 g-NETs were referred to our Unit: 24 (77%), one (3%) and three (10%) resulted types 1, 2 and 3, respectively. Three cases (10%) did not meet the current classification criteria.

RESULTS

The three patients were administered long-term PPIs for gastro-esophageal reflux disease. Patient 1: a 78-year-old man, with a 4-mm well-differentiated g-NET (Ki-67<1%) and marked hypergastrinemia. Patient 2: a 58-year-old man affected by a 6-mm well-differentiated (Ki-67 = 4%) g-NET, with normal gastrin levels. Patients 3: a 67-year-old woman with an 18-mm well-differentiated g-NET (Ki-67 <2%), with mild hypergastrinemia. In the three patients, histology and pertinent blood tests excluded chronic atrophic gastritis, Helicobacter pylori infection or Zollinger-Ellison syndrome. The first two patients underwent endoscopic polypectomy; in the third case total gastrectomy was performed. Further clinical, endoscopic and imaging follow-up did not show any g-NET recurrence.

CONCLUSIONS

The present data point to the existence and epidemiological relevance of g-NETs associated with PPIs intake. These neoplasms are not included in the current classification, thus their treatment and follow-up have not been established.

Use of antacids, alginates and proton pump inhibitors: a survey of the general Danish population using an internet panel

OBJECTIVE

Both over-the-counter medicine, such as antacids or alginates, and proton pump inhibitors (PPI) are used for treating acid-related disorders. We sought to describe what characterizes users of these different medicines, including long-term PPI users within the general population.

METHOD

A cross-sectional survey was conducted in an internet panel representative of the Danish adult population in 2012. Data queried included antacid/alginate and PPI use, reason for therapy, co-medication, and presence of upper gastrointestinal symptoms. Long-term PPI use was defined as using PPI ≥1/3 of the last year (∼120 days). Risk of long-term PPI use was estimated by logistic regression.

RESULTS

A total of 18,223 people received the questionnaire, of which 52% (9390) responded. Antacid/alginate use was reported by 23%; 16% reported use of only antacid/alginate. PPI use was reported by 13.6%; 6.2% were defined as long-term PPI users. Antacid/alginate users were younger, used less co-medication, had most often started on therapy because of reflux symptoms, and had less often ongoing symptoms. Risk of long-term PPI use appeared to be increased in male gender, by renewing PPI prescription by phone/e-mail, using co-medication, and having started on PPI for several reasons. Combination of antacid/alginate and PPI was reported by approximately 50% of those on therapy with weekly or daily symptoms.

CONCLUSION

23% of Danish adults were using antacids or alginates and 14% were using PPI, of which one-half were on long-term therapy. Prescription renewal by phone or e-mail and use of other prescription medication were associated with long-term PPI use, indicating a behavioral pattern, in which unnecessary PPI therapy may be maintained.

Gastroesophageal reflux symptoms not responding to proton pump inhibitor: GERD, NERD, NARD, esophageal hypersensitivity or dyspepsia?

Gastroesophageal reflux (GER) is a common gastrointestinal process that can generate symptoms of heartburn and chest pain. Proton pump inhibitors (PPIs) are the gold standard for the treatment of GER; however, a substantial group of GER patients fail to respond to PPIs. In the past, it was believed that acid reflux into the esophagus causes all, or at least the majority, of symptoms attributed to GER, with both erosive esophagitis and nonerosive outcomes. However, with modern testing techniques it has been shown that, in addition to acid reflux, the reflux of nonacid gastric and duodenal contents into the esophagus may also induce GER symptoms. It remains unknown how weakly acidic or alkaline refluxate with a pH similar to a normal diet induces GER symptoms. Esophageal hypersensitivity or functional dyspepsia with superimposed heartburn may be other mechanisms of symptom generation, often completely unrelated to GER. Detailed studies investigating the pathophysiology of esophageal hypersensitivity are not conclusive, and definitions of the various disease states may overlap and are often confusing. The authors aim to clarify the pathophysiology, definition, diagnostic techniques and medical treatment of patients with heartburn symptoms who fail PPI therapy.

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.

LINX(®) Reflux Management System in chronic gastroesophageal reflux: a novel effective technology for restoring the natural barrier to reflux

Gastroesophageal reflux disease (GERD) results from incompetency of the lower esophageal sphincter that allows the contents of the stomach to reflux into the esophagus, the airways, and the mouth. The disease affects about 10% of the western population and has a profound negative impact on quality of life. The majority of patients are successfully treated with proton-pump inhibitors, but up to 40% have incomplete relief of symptoms even after dose adjustment. The laparoscopic Nissen fundoplication represents the surgical gold standard, but is largely underused because of the level of technical difficulty and the prevalence of side effects. These factors have contributed to the propensity of patients to continue with medical therapy despite inadequate symptom control and complications of the disease. As a consequence, a significant 'therapy gap' in the treatment of GERD remains evident in current clinical practice. The LINX(®) Reflux Management System (Torax Medical, St. Paul, MN, USA) is designed to provide a permanent solution to GERD by augmenting the sphincter barrier with a standardized, reproducible laparoscopic procedure that does not alter gastric anatomy and is easily reversible. Two single-group trials confirmed that a magnetic device designed to augment the lower esophageal sphincter can be safely and effectively implanted using a standard laparoscopic approach. The device decreased esophageal acid exposure, improved reflux symptoms and quality of life, and allowed cessation of proton-pump inhibitors in the majority of patients.

Systematic review: symptoms of rebound acid hypersecretion following proton pump inhibitor treatment

INTRODUCTION

While the physiological existence of rebound acid hypersecretion (RAHS) after withdrawal of proton pump inhibitors (PPI) therapy is established, the clinical implications are less certain. It has been speculated that a clinical relevant rebound phenomenon may be responsible for difficulties in getting off acid-suppressive medication and partly explain the increase in long-term use of PPI. A number of studies addressing this issue have been published recently. The authors aimed to systematically review the existing evidence of clinically relevant symptoms caused by acid rebound following PPI treatment.

MATERIAL AND METHODS

PubMed was searched using the terms "rebound acid hypersecretion" and generic names of PPIs.

RESULTS

Five studies were included. Two studies on asymptomatic volunteers found that 44% experienced acid-related symptoms up to 4 weeks after treatment was withdrawn. Symptoms were generally mild to moderate and mainly heartburn and regurgitation. Three studies, using patients with reflux disease, found no signs of symptoms caused by acid rebound.

CONCLUSION

Gastric acid rebound hypersecretion following PPI therapy induces reflux-like symptoms post-treatment in asymptomatic volunteers, but the significance of this in patient populations is not clear. The studies in patients with reflux disease found no evidence of symptomatic RAHS, but these studies were hampered by severe methodological weaknesses.

The type 2 CCK/gastrin receptor antagonist YF476 acutely prevents NSAID-induced gastric ulceration while increasing iNOS expression

YF476 differs from the proton pump inhibitor (PPI) esomeprazole in mode of action by antagonizing the type 2 receptor of cholecystokinin/gastrin (CCK-2R). YF476 protection against diclofenac-induced gastric ulcers was compared to esomeprazole and correlated with plasma levels of hormones related to gastric pH (gastrin, ghrelin, and somatostatin), gastric gene expression of these hormones, their receptors, and inducible nitric oxide synthase (iNOS). YF476 or esomeprazole pretreatments were followed by diclofenac. Four hours later, gastric tissue was excised and analyzed for ulcer index. An intragastrically implanted Bravo capsule measured pH for 5 days during YF476 plus pentagastrin treatment. Changes in gene expression were assayed for gastrin, ghrelin, and somatostatin; their receptors; and iNOS. YF476 acutely (within 4 h) protected against diclofenac-induced gastric ulcers equivalent to esomeprazole. Gastric pH recorded during 5 days in the presence of pentagastrin was 1.83 (±0.06). YF476 raised pH to 3.67 (±0.09) and plasma ghrelin, gastrin, and somatostatin increased. YF476 increased gene expression of somatostatin receptor and gastrin, while ghrelin receptor decreased; transcripts coding ghrelin, somatostatin, and CCK-2R remained unchanged. In the presence of diclofenac, esomeprazole increased expression of all these transcripts and that of iNOS, while YF476 yielded only decreased CCK-2R and increased iNOS transcripts. YF476 is a potential new preventative treatment for patients at risk of nonsteroidal antiinflammatory drug (NSAID)-induced ulceration. Gastric gene expressions of ghrelin, gastrin, and somatostatin and their receptors differ between esomeprazole and YF476. Despite these differences and different modes of action to raise gastric pH, both drugs acutely increase iNOS, suggesting iNOS expression parallels pH.

Proton pump inhibitors: potential adverse effects

PURPOSE OF REVIEW

This review summarizes adverse effects of potential proton pump inhibitors (PPIs), including nutritional deficiencies (B12 and magnesium), rebound acid hypersecretion, acute interstitial nephritis, gastric carcinoid tumor, cardiovascular risk with clopidogrel and PPI coprescription, bone fractures, enteric infections and pneumonia. An epidemiologic framework is applied to assess clinical relevance and reinforce best practice recommendations.

RECENT FINDINGS

The evidence for PPI adverse events is limited by the absence of Level 1 (randomized controlled trial) studies. The best evidence supports Clostridium difficile and bone fractures in susceptible populations. A substantial reduction in gastrointestinal bleeding risk without increase in cardiovascular events was observed in the COGENT trial when clopidogrel was coprescribed with omeprazole. The risk of pneumonia is inconsistent, and although acute interstitial nephritis, nutritional deficiencies (including B12 and hypomagnesemia), gastric carcinoid and rebound hyperacidity are biologically plausible, studies have failed to demonstrate supportive clinical relevance.

SUMMARY

Prescribe PPI for robust indications only. Strong data supporting risk of adverse events are lacking; however, exercise caution in the elderly and in patients with other risk factors for bone fractures or C. difficile infection.

[Newly recognized side-effects of proton pump inhibitors. Arguments in favour of fundoplication for GERD?]

Among other indications proton pump inhibitors (PPIs) are used as medical treatment of gastroesophageal reflux disease (GERD) and are the most frequently prescribed and most frequently used drugs in gastroenterology. Until recently PPIs were regarded as very safe and associated with very few side-effects. However, during recent years study results have revealed many severe adverse events associated especially with long-term PPI use. We review the currently available evidence, regarding the side-effects of PPIs and discuss the potential impact on treatment strategies for GERD (conservative treatment vs. antireflux surgery). Currently available data suggest that PPIs are associated with osteoporosis-related fractures, Clostridium difficile associated diarrhea (CDAD), community and hospital-acquired pneumonia, pharmacologic interaction with clopidogrel and acetylsalicylic acid with subsequent increased rate of cardiovascular events, refractory hypomagnesemia and rebound reflux symptoms etc. The risk-benefit ratio of PPIs is increasingly recognized as being less favourable. This leads to a more critical viewpoint and raises the question whether the side-effects of PPIs may outweigh the benefits, especially with long-term use. The side-effects of PPIs seem to make a strong argument in favour of laparoscopic fundoplication in the treatment of GERD.

[Adverse effects of proton pump inhibitors: should we worry about long-term exposure?]

Long-term treatment with proton pump inhibitors (PPI) is becoming more prevalent. Although they are well tolerated in the short term, serious concerns about long-term use have arisen. Recent data suggest that the latter is associated with an increased risk for osteoporotic fracture (especially vertebral), Clostridium difficile infection and rebound acid hypersecretion after treatment discontinuation. Acute interstitial nephritis is rare but may progress to chronic renal failure. An increased risk of community-acquired pneumonia has not been established in the general population and seems limited to the most vulnerable patients. Consistent data are still missing to correctly assess the risk of iron deficiency, vitamin B12 deficiency or hypomagnesaemia and the risk of digestive malignant diseases, despite the pathophysiological basis that exists concerning gastric malignancy. Many drug interactions can occur on long-term treatment, including some that imply the cytochrome P450 enzymes. Finally, the risk-benefit balance for a chronic PPI use in children seems unfavorable in most cases.

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.

New pharmacologic approaches in gastroesophageal reflux disease

This article highlights current and emerging pharmacological treatments for gastroesophageal reflux disease (GERD), opportunities for improving medical treatment, the extent to which improvements may be achieved with current therapy, and where new therapies may be required. These issues are discussed in the context of current thinking on the pathogenesis of GERD and its various manifestations and on the pharmacologic basis of current treatments.

Mechanism of acid hypersecretion post curative gastrinoma resection

BACKGROUND

Some patients with Zollinger-Ellison syndrome post curative gastrinoma resection continue to show gastric acid hypersecretion; however, the mechanism is unknown.

AIM

The aim of this study was to prospectively study acid secretion following curative gastrinoma resection and analyze factors contributing in patients with Zollinger-Ellison syndrome.

METHODS

Fifty patients cured post gastrinoma resection were studied with serial assessments of acid secretory status, cure status and ECL-cell status/activity (with serial biopsies, CgA, urinary N-MIAA). Correlative analysis was performed to determine predictive factors.

RESULTS

Hypersecretion occurred in 31 patients (62%) and 14 had extreme-hypersecretion. There was an initial decline (3-6 months) in BAO/MAO, which then remained stable for eight years. Preoperative BAO correlated with the postoperative secretion, but not other clinical, tumoral, laboratory variables, the degree of postoperative acid suppression or type of antisecretory drug needed. Hypersecretors had greater postoperative ECL changes (P=0.005), serum CGA (P=0.009) and 24-h urinary N-MIAA (P=0.0038).

CONCLUSIONS

Post curative resection, gastric hypersecretion persists long term (mean 8 years) in 62% of patients and in 28% it is extreme, despite normogastrinemia. No preoperative variable except BAO correlates with postresection hypersecretion. The persistent increased ECL-cell extent post curative resection suggests prolonged hypergastrinemia can lead to changes in ECL-cells that are either irreversible in humans or sustained by unknown mechanisms not involving fasting hypergastrinemia and which can result in hypersecretion, in a proportion of which it can be extreme. Whether similar findings may occur in patients with idiopathic GERD treated for prolonged periods (>10 years) with PPIs, at present, is unknown.

Laparoscopic sphincter augmentation device eliminates reflux symptoms and normalizes esophageal acid exposure: one- and 2-year results of a feasibility trial

OBJECTIVES

One- and 2-year evaluation of a feasibility trial (clinicaltrials.gov registration numbers NCT01057992, NCT01058070, and 01058564) to assess the safety and efficacy of a laparoscopically implanted sphincter augmentation device for the treatment of gastroesophageal reflux disease (GERD).

METHODS

A sphincter augmentation device (LINX Reflux Management System; Torax Medical, Shoreview, MN), designed to prevent reflux due to abnormal opening of the lower esophageal sphincter (LES), was laparoscopically implanted at the gastroesophageal junction in 44 patients. At baseline, all patients had abnormal esophageal acid exposure on 24-hour pH monitoring and improved, but persistent, typical GERD symptoms while on acid suppression therapy with proton pump inhibitors (PPIs). The device comprises a miniature string of interlinked titanium beads, with magnetic cores, placed around the gastroesophageal junction. The magnetic bond between adjacent beads augments sphincter competence. The beads temporarily separate to accommodate a swallowed bolus, allow belching or vomiting, and reapproximate to augment the LES in the closed position. Patients were evaluated after surgery by GERD Health-Related Quality of Life symptom score, PPI usage, endoscopy, esophageal manometry, and 24-hour esophageal pH monitoring.

RESULTS

The total mean GERD Health-Related Quality of Life symptom scores improved from a mean baseline value of 25.7 to 3.8 and 2.4 at 1- and 2-year follow-up, representing an 85% and 90% reduction, respectively (P < 0.0001). Complete cessation of PPI use was reported by 90% of patients at 1 year and by 86% of patients at 2 years. Early dysphagia occurred in 43% of the patients and self-resolved by 90 days. One device was laparoscopically explanted for persistent dysphagia without disruption of the anatomy or function of the cardia. There were no device migrations, erosions, or induced mucosal injuries. At 1 and 2 years, 77% and 90% of patients had a normal esophageal acid exposure. The mean percentage time pH was less than 4 decreased from a baseline of 11.9% to 3.1% (P < 0.0001) at 1 year and to 2.4% (P < 0.0001) at 2 years. Patient satisfaction was 87% at 1 year and 86% at 2 years.

CONCLUSIONS

The new laparoscopically implanted sphincter augmentation device eliminates GERD symptoms without creating undue side effects and is effective at 1 and 2 years of follow-up.

Proton pump inhibitors and rebound acid hypersecretion

Rebound acid hypersecretion is defined as an increase in gastric acid secretion above pre-treatment levels after cessation of antisecretory therapy. Proton pump inhibitors (PPIs) have been proved to be more effective than histamine-2 receptor antagonists in suppressing intragastric acidity and have therefore become the main choice for management of acid-related complaints. Recent studies have shown that PPI therapy-elicited rebound acid hypersecretion could in turn induce acid-related symptoms. This makes it difficult for patients to cease PPI therapy. Hypergastrinemia is an important mechanism that leads to rebound acid hypersecretion. To reduce the occurrence of rebound acid hypersecretion, efforts should be made to restrict indications for using PPIs.

New pharmacologic approaches in gastroesophageal reflux disease

This article highlights current and emerging pharmacological treatments for gastroesophageal reflux disease (GERD), opportunities for improving medical treatment, the extent to which improvements may be achieved with current therapy, and where new therapies may be required. These issues are discussed in the context of current thinking on the pathogenesis of GERD and its various manifestations and on the pharmacologic basis of current treatments.

Editorial: just how "difficult" is it to withdraw PPI treatment?

Two recent studies-one of which is published in this edition of the American Journal of Gastroenterology-have reported that new dyspeptic or reflux symptoms may develop among previously asymptomatic individuals after withdrawal of a short course of a proton pump inhibitor (PPI). It has been suggested that this is attributable to rebound gastric acid hypersecretion, and that the same phenomenon explains why some patients become chronic PPI users and physicians experience "difficulty" in withdrawing PPI treatment from patients. Although we congratulate the authors of both studies for their controlled observations, we question the generalizability of these observations and hypotheses to the clinical domain. PPI treatment continues to be the optimal management strategy for most patients with gastroesophageal reflux disease and is indicated for chronic use as ulcer prophylaxis in nonsteroidal anti-inflammatory drug takers at high risk for bleeding. However, as with all drugs, PPIs should be dosed appropriately, and should be reserved for patients with conditions for which there is clear evidence of benefit from therapy.

Rebound acid hypersecretion from a physiological, pathophysiological and clinical viewpoint

OBJECTIVE

The recent description of dyspepsia in healthy individuals after stopping treatment with proton-pump inhibitors (PPIs) indicates that reflux disease may worsen due to this treatment. The aim of this paper is to review current knowledge of the regulation of gastric acid secretion, including maximal acid secretion, and to improve understanding of the pathogenesis of acid-related conditions.

MATERIAL AND METHODS

We reviewed our findings from three decades of studies on gastric acid secretion in the isolated rat stomach and in humans as well as studies by the group of Robert Jensen involving gastrinoma patients.

RESULTS

The parietal cell has receptors for histamine and acetylcholine, whereas the gastrin receptor is localized to the enterochromaffin-like (ECL) cell. Gastrin-stimulated histamine release depends on the ECL cell mass, which is regulated by gastrin. The parietal cell mass is also influenced by gastrin. All conditions with hypergastrinemia concomitant with a normal oxyntic mucosa result in an increase in acid secretion. Helicobacter pylori infection in the antral mucosa may induce duodenal ulcers by its effect on acid secretion, as in patients with gastrinoma. Whereas PPIs induce clinically important rebound acid hypersecretion, histamine-2 blockers do not, since they also induce tolerance.

CONCLUSION

From a biological and physiological point of view, patients should be given treatment that disturbs the normal physiology as little as possible.

Dyspepsia as an adverse effect of drugs

Drugs are frequently implicated as a possible cause in new onset dyspeptic symptoms and few drugs are free of this suspicion. Nausea, anorexia, abdominal pain and dyspepsia make up between one-tenth and one-third of reported adverse reactions but they are all so common, both in the background population and among patients, that they are frequently attributed to an illness rather than to medications. No symptom or clinical sign is pathognomonic for adverse drug effects, maybe with the exception of vomiting. Dyspepsia is a common reporting in placebo-arms of treatment trials. Owing to the high background incidence of dyspepsia, it is difficult to discern between spontaneous and true drug-related dyspepsia. The mechanisms by which a drug causes dyspepsia are often unknown even though some drugs are known to cause direct mucosal injury. Non-steroidal anti-inflammatory drugs and antibiotics are common causes of drug-related dyspepsia.

Revisiting the parietal cell

The parietal cell is responsible for secreting concentrated hydrochloric acid into the gastric lumen. To fulfill this task, it is equipped with a broad variety of functionally coupled apical and basolateral ion transport proteins. The concerted scientific effort over the last years by a variety of researchers has provided us with the molecular identity of many of these transport mechanisms, thereby contributing to the clarification of persistent controversies in the field. This article will briefly review the current model of parietal cell physiology and ion transport in particular and will update the existing models of apical and basolateral transport in the parietal cell.