Proton pump inhibitors exacerbate NSAID-induced small intestinal injury by inducing dysbiosis

Physiologic, pathophysiologic, and pharmacologic regulation of gastric acid secretion

PURPOSE OF REVIEW

The present review summarizes the past year's literature, both clinical and basic science, regarding physiologic and pharmacologic regulation of gastric acid secretion in health and disease.

RECENT FINDINGS

Gastric acid kills microorganisms, assists digestion, and facilitates absorption of iron, calcium, and vitamin B12. The main stimulants of acid secretion are the hormone gastrin, released from antral G cells; paracrine agent histamine, released from oxyntic enterochromaffin-like cells; and neuropeptide acetylcholine, released from antral and oxyntic intramural neurons. Gastrin is also a trophic hormone that participates in carcinogenesis. Helicobacter pylori may increase or decrease acid secretion depending upon the acuity and predominant anatomic focus of infection; most patients manifest hypochlorhydria. Despite the fact that proton pump inhibitors (PPIs) are amongst the most widely prescribed drugs, they are underutilized in patients at high risk for UGI bleeding. Although generally considered well tolerated, concerns have been raised regarding associations between PPI use and dementia, kidney disease, myocardial infarction, pneumonia, osteoporosis, dysbiosis, small bowel injury, micronutrient deficiency, and fundic gland polyps.

SUMMARY

Our understanding of the physiologic, pathophysiologic, and pharmacologic regulation of gastric secretion continues to advance. Such knowledge is crucial for improved and safe management of acid-peptic disorders.

The non-invasive exfoliated transcriptome (exfoliome) reflects the tissue-level transcriptome in a mouse model of NSAID enteropathy

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently used classes of medications in the world, yet they induce an enteropathy that is associated with high morbidity and mortality. A major limitation to better understanding the pathophysiology and diagnosis of this enteropathy is the difficulty of obtaining information about the primary site of injury, namely the distal small intestine. We investigated the utility of using mRNA from exfoliated cells in stool as a means to surveil the distal small intestine in a murine model of NSAID enteropathy. Specifically, we performed RNA-Seq on exfoliated cells found in feces and compared these data to RNA-Seq from both the small intestinal mucosa and colonic mucosa of healthy control mice or those exhibiting NSAID-induced enteropathy. Global gene expression analysis, data intersection, pathway analysis, and computational approaches including linear discriminant analysis (LDA) and sparse canonical correlation analysis (CCA) were used to assess the inter-relatedness of tissue (invasive) and stool (noninvasive) datasets. These analyses revealed that the exfoliated cell transcriptome closely mirrored the transcriptome of the small intestinal mucosa. Thus, the exfoliome may serve as a non-invasive means of detecting and monitoring NSAID enteropathy (and possibly other gastrointestinal mucosal inflammatory diseases).

Pharmacological Efficacy/Toxicity of Drugs: A Comprehensive Update About the Dynamic Interplay of Microbes

Oral ingestion is a common, easy to access, route for therapeutic drugs to be delivered. The conception of the gastrointestinal tract as a passive physiological compartment has evolved toward a dynamic perspective of the same. Thus, microbiota plays an important role in contributing with additional metabolic capacities to its host as well as to its phenotypic heterogeneity. These adaptations in turn influence the efficacy and toxicity of a broad range of drugs. Notwithstanding, xenobiotics and therapeutic drugs affecting the microbiome's activity also significantly impact metabolism affecting different organs and tissues, and thereby drugs' toxicity/efficacy effects. Other physiological interfaces (i.e., gut, lungs, and skin) also represent complex media with features about microbiota's composition. In addition, there have been described key regulatory effects of microbes on immunotherapy, because of its potential harnessing the host immune system, mental disorders by modulating neuroendocrine systems and cancer. These alterations are responsible of physiological variations in the response(s) between individuals and populations. However, the study of population-based differences in intestinal microbial-related drug metabolism has been largely inferential. This review outlines major reciprocal implications between drugs and microbes regulatory capacities in pharmacotherapy.

Non-steroidal anti-inflammatory drug-induced enteropathy

Non-steroidal anti-inflammatory drugs (NSAIDs) are well known to be associated with serious upper gastrointestinal complications, such as peptic ulcer, bleeding, perforation, and obstruction. Recently, attention has been mainly focused on the small bowel injuries caused by NSAIDs, and new endoscopic techniques such as capsule endoscopy and double balloon endoscopy can help in detecting such injuries. This article reviewed the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of small bowel injuries caused by NSAIDs. Small bowel injures by NSAIDs might occur with a similar frequency and extent as those observed in the upper gastrointestinal tract. The pathogenesis of NSAID-induced enteropathy is complex and not clearly understood. The various lesions observed in the small bowel, including petechiae, reddened folds, loss of villi, erosions, and ulcers can be detected by capsule endoscopy. A drug that could prevent or treat NSAID-induced enteropathy has not yet been developed. Therefore, further investigations should be performed to elucidate the pathogenesis of such enteropathy and develop suitable preventive and treatment strategies.

From clinical uncertainties to precision medicine: the emerging role of the gut barrier and microbiome in small bowel functional diseases

Over the last decade, remarkable progress has been made in the understanding of disease pathophysiology. Many new theories expound on the importance of emerging factors such as microbiome influences, genomics/omics, stem cells, innate intestinal immunity or mucosal barrier complexities. This has introduced a further dimension of uncertainty into clinical decision-making, but equally, may shed some light on less well-understood and difficult to manage conditions. Areas covered: Comprehensive review of the literature on gut barrier and microbiome relevant to small bowel pathology. A PubMed/Medline search from 1990 to April 2017 was undertaken and papers from this range were included. Expert commentary: The scenario of clinical uncertainty is well-illustrated by functional gastrointestinal disorders (FGIDs). The movement towards achieving a better understanding of FGIDs is expressed in the Rome IV guidelines. Novel diagnostic and therapeutic protocols focused on the GB and SB microbiome can facilitate diagnosis, management and improve our understanding of the underlying pathological mechanisms in FGIDs.

Gut microbiota composition is associated with polypharmacy in elderly hospitalized patients

Reduced biodiversity and increased representation of opportunistic pathogens are typical features of gut microbiota composition in aging. Few studies have investigated their correlation with polypharmacy, multimorbidity and frailty. To assess it, we analyzed the fecal microbiota from 76 inpatients, aged 83 ± 8. Microbiome biodiversity (Chao1 index) and relative abundance of individual bacterial taxa were determined by next-generation 16S rRNA microbial profiling. Their correlation with number of drugs, and indexes of multimorbidity and frailty were verified using multivariate linear regression models. The impact of gut microbiota biodiversity on mortality, rehospitalizations and incident sepsis was also assessed after a 2-year follow-up, using Cox regression analysis. We found a significant negative correlation between the number of drugs and Chao1 Index at multivariate analysis. The number of drugs was associated with the average relative abundance of 15 taxa. The drug classes exhibiting the strongest association with single taxa abundance were proton pump inhibitors, antidepressants and antipsychotics. Conversely, frailty and multimorbidity were not significantly associated with gut microbiota biodiversity. Very low Chao1 index was also a significant predictor of mortality, but not of rehospitalizations and sepsis, at follow-up. In aging, polypharmacy may thus represent a determinant of gut microbiota composition, with detrimental clinical consequences.

Gaseous Mediators in Gastrointestinal Mucosal Defense and Injury

Of the numerous gaseous substances that can act as signaling molecules, the best characterized are nitric oxide, carbon monoxide and hydrogen sulfide. Contributions of each of these low molecular weight substances, alone or in combination, to maintenance of gastrointestinal mucosal integrity have been established. There is considerable overlap in the actions of these gases in modulating mucosal defense and responses to injury, and in some instances they act in a cooperative manner. Each also play important roles in regulating inflammatory and repair processes throughout the gastrointestinal tract. In recent years, significant progress has been made in the development of novel anti-inflammatory and cytoprotective drugs that exploit the beneficial activities of one or more of these gaseous mediators.

The intestinal barrier: a fundamental role in health and disease

The gastrointestinal mucosa constitutes a critical barrier where millions of microbes and environmental antigens come in close contact with the host immune system. Intestinal barrier defects have been associated with a broad range of diseases and therefore denote a new therapeutic target. Areas covered: This review is based on an extensive literature search in PubMed of how the intestinal barrier contributes to health and as a trigger for disease. It discusses the anatomy of the intestinal barrier and explains the available methods to evaluate its function. Also reviewed is the importance of diet and lifestyle factors on intestinal barrier function, and three prototypes of chronic diseases (inflammatory bowel disease, celiac disease and nonalcoholic fatty liver disease) that have been linked to barrier defects are discussed. Expert commentary: The intestinal barrier has been investigated by various methods, but correlation of results across studies is difficult, representing a major shortcoming in the field. New upcoming techniques and research on the effect of barrier-restoring therapeutics may improve our current understanding of the gut barrier, and provide a step forward towards personalised medicine.

Peptic ulcer disease

The rapidly declining prevalence of Helicobacter pylori infection and widespread use of potent anti-secretory drugs means peptic ulcer disease has become substantially less prevalent than it was two decades ago. Management has, however, become more challenging than ever because of the threat of increasing antimicrobial resistance worldwide and widespread use of complex anti-thrombotic therapy in the ageing population. Peptic ulcers not associated with H pylori infection or the use of non-steroidal anti-inflammatory drugs are now also imposing substantial diagnostic and therapeutic challenges. This Seminar aims to provide a balanced overview of the latest advances in the pathogenetic mechanisms of peptic ulcers, guidelines on therapies targeting H pylori infection, approaches to treatment of peptic ulcer complications associated with anti-inflammatory analgesics and anti-thrombotic agents, and the unmet needs in terms of our knowledge and management of this increasingly challenging condition.

Proton pump inhibitor therapy did not increase the prevalence of small-bowel injury: A propensity-matched analysis

Background

Previous studies have reported that the suppression of acid secretion by using proton pump inhibitors (PPIs) results in dysbiosis of the small-bowel microbiota, leading to exacerbated small-bowel injuries, including erosions and ulcers. This study was designed to assess the association between PPI therapy and small-bowel lesions after adjustment for the differences in baseline characteristics between users and non-users of PPIs.

Methods

We retrospectively studied patients suspected to be suffering from small-bowel diseases, who underwent capsule endoscopy between 2010 and 2013. We used propensity matching to adjust for the differences in baseline characteristics between users and non-users of PPIs. The outcomes included the prevalence of small-bowel lesions: erosion, ulcer, angioectasia, varices, and tumor.

Results

We selected 327 patient pairs for analysis after propensity matching, and found no significant differences in the prevalence of small-bowel injuries, including erosions and ulcers, between users and non-users of PPIs. Two subgroup analyses of the effect of the type of PPI and the effect of PPI therapy in users and non-users of nonsteroidal anti-inflammatory drugs indicated no significant differences in the prevalence of small-bowel injuries in these two groups.

Conclusion

PPI therapy did not increase the prevalence of small-bowel injury, regardless of the type of PPI used and the use of nonsteroidal anti-inflammatory drugs.

The influence of CYP2C19 polymorphisms on exacerbating effect of rabeprazole in celecoxib-induced small bowel injury

BACKGROUND

Simultaneous use of proton pump inhibitors (PPIs) has been shown to increase the risk of nonsteroidal anti-inflammatory drug (NSAID)-induced small bowel injury.

AIM

To investigate whether polymorphisms of the cytochrome P450 2C19 gene (CYP2C19), encoding a key metabolising enzyme for PPIs, are associated with small bowel injury induced by celecoxib in combination with the PPI rabeprazole.

METHODS

Study participants included 55 healthy Japanese volunteers, who participated in the PPI-NSAID Kyushu University Study using video capsule endoscopy. For 2 weeks, 26 subjects were treated with celecoxib plus rabeprazole (rabeprazole group), and 29 subjects received celecoxib plus placebo (placebo group). All subjects were genotyped for CYP2C19 using real-time fluorescent polymerase chain reaction. Subjects were sub-classified as poor metabolizers or extensive metabolizers. The incidence and number of small bowel injuries were compared between poor metabolizers and extensive metabolizers in each group.

RESULTS

In the rabeprazole group, the incidence of small bowel injuries was significantly higher in poor metabolizers than in extensive metabolizers (85.7% vs 31.6%, P=.026). The number of mucosal injuries in the rabeprazole group was also significantly higher in poor metabolizers compared with extensive metabolizers (median [range] 3 [0-31] vs 0 [0-7], P=.01). In addition, we found a significant interaction between CYP2C19 genotype and concomitant use of rabeprazole in subjects at risk for celecoxib-induced small bowel injury.

CONCLUSIONS

The CYP2C19 genotype might be associated with the risk of small bowel injury when celecoxib is combined with rabeprazole.

FFA2 activation combined with ulcerogenic COX inhibition induces duodenal mucosal injury via the 5-HT pathway in rats

Serotonin (5-HT), predominantly synthesized and released by enterochromaffin cells, is implicated in gastrointestinal symptoms such as emesis, abdominal pain, and diarrhea. Because luminal short-chain fatty acids (SCFAs) release 5-HT from enterochromaffin cells, which express the SCFA receptor free fatty acid receptor 2 (FFA2) in rat duodenum, we examined the effects of the selective FFA2 agonist phenylacetamide-1 (PA1) on duodenal 5-HT release with consequent bicarbonate secretion [duodenal bicarbonate secretion (DBS)] and on indomethacin (IND)-induced enteropathy. Intestinal injury was induced by IND (10 mg/kg sc) with or without PA1. We measured DBS in vivo in a duodenal loop perfused with PA1 while measuring 5-HT released in the portal vein. Duodenal blood flow was measured by laser-Doppler flowmetry. IND induced small intestinal ulcers with duodenal sparing. PA1 given with IND (IND + PA1) dose dependently induced duodenal erosions. IND + PA1-induced duodenal lesions were inhibited by the FFA2 antagonist GLPG-0974, ondansetron, or omeprazole but not by RS-23597 or atropine. Luminal perfusion of PA1 augmented DBS accompanied by increased portal blood 5-HT concentrations with approximately eight times more release at 0.1 mM than at 1 µM, with the effects inhibited by coperfusion of GLPG-0974. Luminal PA1 at 1 µM increased, but at 0.1 mM diminished, duodenal blood flow. Cosuperfusion of PA1 (0.1 mM) decreased acid-induced hyperemia, further reduced by IND pretreatment but restored by ondansetron. These results suggest that, although FFA2 activation enhances duodenal mucosal defenses, FFA2 overactivation during ulcerogenic cyclooxygenase inhibition may increase the vulnerability of the duodenal mucosa to gastric acid via excessive 5-HT release and 5-HT₃ receptor activation, implicated in foregut-related symptoms such as emesis and epigastralgia.NEW & NOTEWORTHY Luminal free fatty acid receptor 2 agonists stimulate enterochromaffin cells and release serotonin, which enhances mucosal defenses in rat duodenum. However, overdriving serotonin release with high luminal concentrations of free fatty acid 2 ligands such as short-chain fatty acids injures the mucosa by decreasing mucosal blood flow. These results are likely implicated in serotonin-related dyspeptic symptom generation because of small intestinal bacterial overgrowth, which is hypothesized to generate excess SCFAs in the foregut, overdriving serotonin release from enterochromaffin cells.

Evidence against the participation of a pharmacokinetic interaction in the protective effect of single-dose curcumin against gastrointestinal damage induced by indomethacin in rats

OBJECTIVE

To determine the role of a pharmacokinetic interaction in the protective effect of curcumin against the gastric damage induced by indomethacin administration as such or as its prodrug acemetacin.

METHODS

Wistar rats orally received single dose of indomethacin (30 mg/kg) with and without curcumin (30 mg/kg); gastric injury was evaluated by determining the total damaged area. Additional groups of rats received an oral single dose of indomethacin (30 mg/kg) or its prodrug acemetacin (34.86 mg/kg) in the presence or absence of curcumin (30 mg/kg). Indomethacin and acemetacin concentrations in plasma from blood draws were determined by high-performance liquid chromatography.Plasma concentration-against-time curves were constructed, and bioavailability parameters, maximal concentration (C_max) and area under the curve to the last sampling time (AUC_0-t) were estimated.

RESULTS

Concomitant administration of indomethacin and curcumin resulted in a significantly reduced gastric damage compared to indomethacin alone. However, co-administration of curcumin did not produce any significant alteration in the bioavailability parameters of indomethacin and acemetacin after administration of either the active compound or the prodrug.

CONCLUSION

Curcumin exhibits a protective effect against indomethacin-induced gastric damage, but does not produce a reduction of the bioavailability of this nonsteroidal anti-inflammatory drug, indomethacin. Data thus suggest that a pharmacokinetic mechanism of action is not involved in curcumin gastroprotection.

FFA3 Activation Stimulates Duodenal Bicarbonate Secretion and Prevents NSAID-Induced Enteropathy via the GLP-2 Pathway in Rats

BACKGROUND

Therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with enteropathy in humans and experimental animals, a cause of considerable morbidity. Unlike foregut NSAID-associated mucosal lesions, most treatments for this condition are of little efficacy. We propose that the endogenously released intestinotrophic hormone glucagon-like peptide-2 (GLP-2) prevents the development of NSAID-induced enteropathy. Since the short-chain fatty acid receptor FFA3 is expressed on enteroendocrine L cells and on enteric nerves in the gastrointestinal tract, we further hypothesized that activation of FFA3 on L cells protects the mucosa from injury via GLP-2 release with enhanced duodenal HCO₃^- secretion. We thus investigated the effects of synthetic selective FFA3 agonists with consequent GLP-2 release on NSAID-induced enteropathy.

METHODS

We measured duodenal HCO₃^- secretion in isoflurane-anesthetized rats in a duodenal loop perfused with the selective FFA3 agonists MQC or AR420626 (AR) while measuring released GLP-2 in the portal vein (PV). Intestinal injury was produced by indomethacin (IND, 10 mg/kg, sc) with or without MQC (1-10 mg/kg, ig) or AR (0.01-0.1 mg/kg, ig or ip) treatment.

RESULTS

Luminal perfusion with MQC or AR (0.1-10 µM) dose-dependently augmented duodenal HCO₃^- secretion accompanied by increased GLP-2 concentrations in the PV. The effect of FFA3 agonists was inhibited by co-perfusion of the selective FFA3 antagonist CF3-MQC (30 µM). AR-induced augmented HCO₃^- secretion was reduced by iv injection of the GLP-2 receptor antagonist GLP-2(3-33) (3 nmol/kg), or by pretreatment with the cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor CFTR_inh-172 (1 mg/kg, ip). IND-induced small intestinal ulcers were dose-dependently inhibited by intragastric administration of MQC or AR. GLP-2(3-33) (1 mg/kg, ip) or CF3-MQC (1 mg/kg, ig) reversed AR-associated reduction in IND-induced enteropathy. In contrast, ip injection of AR had no effect on enteropathy.

CONCLUSION

These results suggest that luminal FFA3 activation enhances mucosal defenses and prevents NSAID-induced enteropathy via the GLP-2 pathway. The selective FFA3 agonist may be a potential therapeutic candidate for NSAID-induced enteropathy.

Human Gut Microbiota: Toward an Ecology of Disease

Composed of trillions of individual microbes, the human gut microbiota has adapted to the uniquely diverse environments found in the human intestine. Quickly responding to the variances in the ingested food, the microbiota interacts with the host via reciprocal biochemical signaling to coordinate the exchange of nutrients and proper immune function. Host and microbiota function as a unit which guards its balance against invasion by potential pathogens and which undergoes natural selection. Disturbance of the microbiota composition, or dysbiosis, is often associated with human disease, indicating that, while there seems to be no unique optimal composition of the gut microbiota, a balanced community is crucial for human health. Emerging knowledge of the ecology of the microbiota-host synergy will have an impact on how we implement antibiotic treatment in therapeutics and prophylaxis and how we will consider alternative strategies of global remodeling of the microbiota such as fecal transplants. Here we examine the microbiota-human host relationship from the perspective of the microbial community dynamics.

Prophylaxis for Stress Ulcers With Proton Pump Inhibitors Is Not Associated With Increased Risk of Bloodstream Infections in the Intensive Care Unit

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) have been associated with increased risk of infection, likely because of changes in intestinal epithelial permeability and the gastrointestinal microbiome. PPIs are frequently given to patients in the intensive care unit (ICU) to prevent stress ulcers. These patients are at risk for bloodstream infections (BSIs), so we investigated the relationship between PPI use and BSIs among patients in the ICU.

METHODS

We performed a retrospective cohort study of adults (≥18 years) admitted to 1 of 14 ICUs within a hospital network of 3 large hospitals from 2008 through 2014. The primary exposure was PPI use for stress ulcer prophylaxis in the ICU. The primary outcome was BSI, confirmed by culture analysis, arising 48 hours or more after admission to the ICU. Subjects were followed for 30 days after ICU admission or until death, discharge, or BSI. Multivariable Cox proportional hazards modeling was used to test the association between PPIs and BSI after controlling for patient comorbidities and other clinical factors.

RESULTS

We analyzed data from 24,774 patients in the ICU, including 756 patients (3.1%) who developed BSIs while in the ICU. The cumulative incidence of BSI was 3.7% in patients with PPI exposure compared with 2.2% in patients without PPI exposure (log-rank test, P < .01). After adjusting for potential confounders, PPI exposure was not associated with increased risk of BSI while in the ICU (adjusted hazard ratio, 1.08; 95% confidence interval, 0.91-1.29). Comorbidities, antibiotic use, and mechanical ventilation were all independently associated with increased risk for BSIs.

CONCLUSIONS

In a retrospective study of patients in the ICU, administration of PPIs to prevent bleeding was not associated with increased risk of BSI. These findings indicate that concern for BSI should not affect decisions regarding use of PPIs in the ICU.

Aspirin and omeprazole for secondary prevention of cardiovascular disease in patients at risk for aspirin-associated gastric ulcers

INTRODUCTION

Cardiovascular disease is the most important cause of morbidity and mortality in the world and low-dose aspirin is considered the cornerstone of the cardiovascular disease prevention. However, low-dose aspirin use is associated with gastrointestinal adverse effects in the whole gastrointestinal tract. In this setting, co-therapy with a proton pump inhibitor is the most accepted strategy to reduce aspirin related upper gastrointestinal damage. In addition, some adverse effects have been described with proton pump inhibitors long term use. Areas covered: Low-dose aspirin related beneficial and adverse effects in cardiovascular system and gastrointestinal tract are reviewed. In addition, this manuscript summarizes current data on upper gastrointestinal damage prevention and adverse events with proton pump inhibition. Finally, we discuss the benefit/risk ratio of proton pump inhibitor use in patients at risk of gastrointestinal damage taking low-dose aspirin. Expert commentary: Nowadays, with the current available evidence, the combination of low-dose aspirin with proton pump inhibitor is the most effective therapy for cardiovascular prevention in patients at high gastrointestinal risk. However, further studies are needed to discover new effective strategies with less related adverse events.

Management for non-variceal upper gastrointestinal bleeding in elderly patients: the experience of a tertiary university hospital

BACKGROUND

Peptic ulcer bleeding (PUB) is the main cause of non-variceal upper gastrointestinal bleeding (UGIB). Endoscopic treatment and acid suppression with proton-pump inhibitors (PPIs) are most important in the management of PUB and these treatments have reduced mortality. However, elderly patients sometimes have a poor prognostic outcome due to severe comorbidities.

METHODS

A retrospective study was performed on 504 cases with acute non-variceal UGIB who were examined in our hospital, in order to reveal the risk factor of a poor outcome in elderly patients.

RESULTS

Two hundred and thirty-four cases needed hemostasis; 11 cases had unsuccessful endoscopic treatments; 31 cases had re-bleeding after endoscopic hemostasis. Forty-three cases died within 30 days after the initial urgent endoscopy, but only seven cases died from bleeding. Elderly patients aged over 65 years had more severe comorbidities, and were prescribed non-steroidal anti-inflammatory drugs (NSAIDs), antiplatelet agents and/or anticoagulation agents, more frequently, compared with non-elderly patients. The significant risk factor of needing hemostatic therapy was the taking of two or more NSAIDs, antiplatelet agents and/or anticoagulation agents. The most important risk of a poor outcome in elderly patients was various kinds of severe comorbidities. And so, it is important to predict such an outcome in these cases. AIMS65 is a simple and relatively useful scoring system that predicts the risk of a poor outcome in UGIB. High-score patients via AIMS65 were associated with a high mortality rate because of death from comorbidities.

CONCLUSIONS

The elderly patients in whom were prescribed two or more NSAIDs, antiplatelet agents and/or anticoagulation agents, should have UGIB prevented using a PPI. The most significant risk of a poor outcome in elderly patients was severe comorbidities. We recommend that elderly patients with UGIB should be estimated as having a poor outcome as soon as possible via the risk scoring system AIMS65.

Role of non-steroidal anti-inflammatory drugs on intestinal permeability and nonalcoholic fatty liver disease

The use of non-steroidal anti-inflammatory drugs (NSAIDs) is widespread worldwide thanks to their analgesic, anti-inflammatory and antipyretic effects. However, even more attention is placed upon the recurrence of digestive system complications in the course of their use. Recent data suggests that the complications of the lower gastro-intestinal tract may be as frequent and severe as those of the upper tract. NSAIDs enteropathy is due to enterohepatic recycling of the drugs resulting in a prolonged and repeated exposure of the intestinal mucosa to the compound and its metabolites. Thus leading to so-called topical effects, which, in turn, lead to an impairment of the intestinal barrier. This process determines bacterial translocation and toxic substances of intestinal origin in the portal circulation, leading to an endotoxaemia. This condition could determine a liver inflammatory response and might promote the development of non-alcoholic steatohepatitis, mostly in patients with risk factors such as obesity, metabolic syndrome and a high fat diet, which may induce a small intestinal bacterial overgrowth and dysbiosis. This alteration of gut microbiota may contribute to nonalcoholic fatty liver disease and its related disorders in two ways: firstly causing a malfunction of the tight junctions that play a critical role in the increase of intestinal permeability, and then secondly leading to the development of insulin resistance, body weight gain, lipogenesis, fibrogenesis and hepatic oxidative stress.

A Curious Case of Intestinal Diaphragm Disease Unmasked by Perforation of a Duodenal Ulcer

Nonsteroidal anti-inflammatory drugs are a common cause of intestinal injury. A variety of NSAID-induced injuries may occur including ulcers, erosions, colitis, strictures, and diaphragm disease. Diaphragm disease refers to the development of multiple thin, concentric, stenosing strictures in the intestine. Strictures occur most often in the midintestine and are thought to be pathognomonic of NSAID damage. They can lead to intermittent or complete bowel obstruction. Diagnosis may be elusive as there is nothing specific about NSAID-induced injury at endoscopy and histology is also nonspecific. Even at laparotomy, the diagnosis of diaphragm disease may be missed as the serosa may appear normal and strictures can be difficult to palpate. While most NSAID-induced lesions tend to resolve quickly following withdrawal of the offending drug, diaphragm-like strictures usually require intervention such as stricturoplasty or surgical resection of the involved segment of bowel. Here we report the case of a 60-year-old male patient who presented with iron deficiency anaemia and recurrent subacute bowel obstruction. Following endoscopy and repeated CT scanning of his abdomen, he was diagnosed with Crohn's disease. He was treated with 5-ASAs and immune suppression until a perforated duodenal ulcer resulted in emergency laparotomy and the subsequent discovery of multiple intestinal diaphragms attributable to long-standing NSAID use.

Factors associated with villus atrophy in symptomatic coeliac disease patients on a gluten-free diet

BACKGROUND

Duodenal injury persists in some coeliac disease patients despite gluten-free diet, and is associated with adverse outcomes.

AIM

To determine the prevalence and clinical risk factors for persistent villus atrophy among symptomatic coeliac disease patients.

METHODS

A nested cross-sectional analysis was performed on coeliac disease patients with self-reported moderate or severe symptoms while following a gluten-free diet, who underwent protocol-mandated duodenal biopsy upon enrolment in the CeliAction clinical trial. Demographic factors, symptom type, medication use, and serology were examined to determine predictors of persistent villus atrophy.

RESULTS

Of 1345 symptomatic patients, 511 (38%, 95% CI, 35-41%) were found to have active coeliac disease with persistent villus atrophy, defined as average villus height to crypt depth ratio ≤2.0. On multivariable analysis, older age (OR, 5.1 for ≥70 vs. 18-29 years, 95% CI, 2.5-10.4) was a risk factor while longer duration on gluten-free diet was protective (OR, 0.37, 95% CI, 0.24-0.55 for 4-5.9 vs. 1-1.9 years). Villus atrophy was associated with use of proton-pump inhibitors (PPIs; OR, 1.6, 95% CI, 1.1-2.3), non-steroidal anti-inflammatory drugs (NSAIDs; OR, 1.64, 95% CI, 1.2-2.2), and selective serotonin reuptake inhibitors (SSRIs; OR, 1.74, 95% CI, 1.2-2.5). Symptoms were not associated with villus atrophy after adjusting for covariates. Conclusions A majority of symptomatic coeliac disease patients did not have active disease on follow-up histology. Symptoms were poorly predictive of persistent mucosal injury. The impact of NSAIDs, PPIs, and SSRIs on mucosal healing in coeliac disease warrants further study.

Current Topics of Strategy of NSAID-Induced Small Intestinal Lesions

Small intestinal mucosal injuries have been recently recognized as common complications associated with non-steroidal anti-inflammatory drugs (NSAIDs) because video capsule endoscopy and balloon enteroscopy are now available for the detection of small intestinal lesions. Small intestinal injury occurs not in an acid-dependent mechanism but by various factors such as enteric bacteria, bile acids, prostaglandin (PG) deficiency and topical factors (abnormal intestinal mucosal permeability, mitochondrial dysfunction, reactive oxygen species, endoplasmic reticulum stress and so on), and there is no well-established prophylactic approach. Several experimental and clinical studies found the effectiveness of some of the mucoprotective drugs, PG analogs, but not that of acid suppressants. Considering the effect of proton pump inhibitors (PPIs) for upper gastrointestinal (GI) disease and in the small intestine, the following 2 kinds of strategies against NSAID-induced GI injuries may be recommended. In patients with a high risk of upper GI disease (peptic ulcer etc.), simultaneous administration of a PPI (for upper GI disease) and a mucoprotective drug (for small intestine) is needed to prevent NSAID-induced GI injury. In other cases, an effective mucoprotective drug is enough for the protection of the entire digestive tract, that is, starting from the esophagus to the small intestine. These strategies may fulfill both economical and curative effects.

Localized delivery of curcumin from injectable gelatin/Thai silk fibroin microspheres for anti-inflammatory treatment of osteoarthritis in a rat model

The previously developed gelatin/silk fibroin microspheres were loaded with curcumin and applied for anti-inflammatory treatment in monosodium iodoacetate (MIA)-induced osteoarthritis (OA) in a rat model. The MIA-induced OA rats received a single intra-articular injection with gelatin or gelatin/silk fibroin (30/70) microspheres encapsulating curcumin. The therapeutic effects of treatment groups [concentration of interleukin-6 (IL-6) in blood serum, radiographic and the histological grading on articular joint] were compared with those of normal saline treated OA and normal rats. The result showed that both microsphere groups reduced the level of IL-6 in serum after 1 week of treatment. The gelatin/silk fibroin (30/70) microspheres encapsulating curcumin delayed the cellular destruction in articular joint and synovial tissue after 8 weeks. The radiographic and histological gradings on articular cartilage lesion and synovial tissue change of rats treated with gelatin/silk fibroin (30/70) microspheres encapsulating curcumin were close to those of the normal rats. It was explained that the slow-degrading gelatin/silk fibroin (30/70) microspheres released curcumin for extended period and showed a prolonged anti-inflammatory effect, compared to the fast-degrading gelatin microspheres. This delivery system of curcumin was suggested to be applied for localized treatment of anti-inflammatory in OA with minimal invasion.

Microbiota Plays a Key Role in Non-Steroidal Anti-Inflammatory Drug-Induced Small Intestinal Damage

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) damage the small intestine by causing multiple erosions and ulcers. However, to date, no established therapies and prophylactic agents are available to treat such damages. We reviewed the role of intestinal microbiota in NSAID-induced intestinal damage and identified potential therapeutic candidates.

SUMMARY

The composition of the intestinal microbiota is an important factor in the pathophysiology of NSAID-induced small intestinal damage. Once mucosal barrier function is disrupted due to NSAID-induced prostaglandin deficiency and mitochondrial malfunction, lipopolysaccharide from luminal gram-negative bacteria and high mobility group box 1 from the injured epithelial cells activate toll-like receptor 4-signaling pathway and nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 inflammasome; this leads to the release of proinflammatory cytokines such as tumor necrosis factor-α and interleukin-1β. Proton pump inhibitors (PPIs) are often used for the prevention of NSAID-induced injuries to the upper gastrointestinal tract. However, several studies indicate that PPIs may induce dysbiosis, which may exacerbate the NSAID-induced small intestinal damage. Our recent research suggests that probiotics and rebamipide could be used to prevent NSAID-induced small intestinal damage by regulating the intestinal microbiota. Key Messages: Intestinal microbiota plays a key role in NSAID-induced small intestinal damage, and modulating the composition of the intestinal microbiota could be a new therapeutic strategy for treating this damage.

Gut Microbiota Mediates Protection Against Enteropathy Induced by Indomethacin

Non-steroidal anti-inflammatory drugs (NSAIDs) can cause significant small bowel injuries. The role of gut microbiota in this NSAID-induced enteropathy is poorly understood. We studied the dynamic changes in gut microbiota following indomethacin administration in mice, and investigated the effects of these adaptive changes on subsequent NSAID-induced enteropathy. The changes in gut microbiota were studied using 16S rRNA sequencing, and the effects of such changes were investigated using antibiotics and a faecal transplantation model. After indomethacin treatment, significant adaptive changes in gut microbiota were observed, including increased abundance of Firmicutes and decreased abundance in that of Bacteroidetes. Depletion of gut microbiota with antibiotics led to a higher mortality (P = 0.0021) in mice compared to controls. Mice pre-transplanted with adaptively changed microbiota showed less small bowel injury and lower levels of pro-inflammatory cytokines when exposed to indomethacin. In summary, this study identifies adaptive changes in the gut microbiota upon indomethacin administration, which can in turn ameliorate further NSAID-induced injury. The heightened mortality with antibiotic depletion of the adaptively changed microbiota suggests its important role in protecting against such injury. This study provides insight for future efforts to target the microbiota as a therapeutic strategy.

Role of Sulforaphane in Protection of Gastrointestinal Tract Against H. pylori and NSAID-Induced Oxidative Stress

BACKGROUND

Sulforaphane (SFN), a phytochemical found in abundance in broccoli sprouts, potently induces a variety of antioxidant enzymes, and thereby protects cells from injury induced by various kinds of oxidative stresses. It has been suggested that both H. pylori infection and intake of non-steroidal anti-inflammatory drugs (NSAIDs) induce chronic oxidative stress in gastrointestinal (GI) mucosa, thereby causing mucosal injury in the GI tract. Therefore, it would be a reasonable assumption that SFN protects GI mucosa against oxidative injury induced by H. pylori or NSAIDs.

METHODS

We examined the effects of SFN on H. pylori viability in vitro, levels of gastritis in H.pylori-infected mice in vivo, and in H.pylori-infected human subjects. We also examined the effects of SFN on NSAID-induced small intestinal injury in mice.

RESULTS

Our data from the H. pylori infection study clearly demonstrated that SFN inhibited H. pylori viability both in vitro and in vivo, and mitigated H. pylori-induced gastritis in mice and humans. Similarly, our study on NSAID-induced small intestinal injury showed that SFN not only mitigated aspirin-induced injury of small intestinal epithelial cells in vitro, but also ameliorated indomethacin-induced small intestinal injury in mice in vivo.

CONCLUSIONS

These data strongly suggest that SFN contributes to the protection of GI mucosa against oxidative injury induced by H. pylori or NSAIDs.

Oxidative stress controlling agents are effective for small intestinal injuries induced by non-steroidal anti-inflammatory drugs

BACKGROUND AND AIM

Video-capsule endoscopy (VCE) has shown that intestinal ulcers are common in non-steroidal anti-inflammatory drugs (NSAIDs) users, although the mechanisms and management have not been clearly defined. To explore the contribution of oxidative stress and potential of anti-oxidants for NSAIDs-induced intestinal ulcers, we assessed human serum oxidative stress balance and the effect of anti-oxidants using a mouse model.

METHODS

A total of 30 NSAIDs users (17 aspirin and 13 non-aspirin users) received VCE. Serum reactive oxygen metabolite (d-ROM) and antioxidative OXY-adsorbent test (OXY) were measured. The indomethacin (IND)-induced mouse intestinal ulcer model was used to assess the effect of anti-oxidants. Eight-week-old mice were divided into four groups; control diet and diet including IND (N group), IND and L-carnitine (NC group), and IND and vitamin E (NE group).

RESULTS

Serum OXY levels among non-aspirin users were lower in the mucosal injuries positive group than the negative group (P < 0.05). In the mouse models, the degree of mucosal injuries was lower in NC and NE than N (P < 0.01). Serum d-ROM levels were lower in NC and NE than N (P < 0.01), and OXY levels were higher in NC than N and NE (P < 0.01). The degeneration of intestinal mitochondria was mild in NC and NE. The serum KC/CXCL-1 level and hepatic expression of the anti-oxidant molecule Gpx4 were lower in NC than N.

CONCLUSIONS

Non-aspirin NSAID-induced intestinal ulcers are related to decreased anti-oxidative stress function. Anti-oxidants, especially L-carnitine, are good candidates for intestinal ulcers.

Mechanisms of inflammation-driven bacterial dysbiosis in the gut

The gut microbiota has diverse and essential roles in host metabolism, development of the immune system and as resistance to pathogen colonization. Perturbations of the gut microbiota, termed gut dysbiosis, are commonly observed in diseases involving inflammation in the gut, including inflammatory bowel disease, infection, colorectal cancer and food allergies. Importantly, the inflamed microenvironment in the gut is particularly conducive to blooms of Enterobacteriaceae, which acquire fitness benefits while other families of symbiotic bacteria succumb to environmental changes inflicted by inflammation. Here we summarize studies that examined factors in the inflamed gut that contribute to blooms of Enterobacterieaceae, and highlight potential approaches to restrict Enterobacterial blooms in treating diseases that are otherwise complicated by overgrowth of virulent Enterobacterial species in the gut.

Protons pump inhibitor treatment and lower gastrointestinal bleeding: Balancing risks and benefits

Proton pump inhibitors (PPIs) represent a milestone in the treatment of acid-related diseases, and are the mainstay in preventing upper gastrointestinal bleeding in high-risk patients treated with nonsteroidal anti-inflammatory drugs (NSAIDs) or low-dose aspirin. However, this beneficial effect does not extend to the lower gastrointestinal tract. PPIs do not prevent NSAID or aspirin-associated lower gastrointestinal bleeding (LGB). PPIs may increase both small bowel injury related to NSAIDs and low-dose aspirin treatment and the risk of LGB. Recent studies suggested that altering intestinal microbiota by PPIs may be involved in the pathogenesis of NSAID-enteropathy. An increase in LGB hospitalization rates may occur more frequently in older patients with more comorbidities and are associated with high hospital resource utilization, longer hospitalization, and increased mortality. Preventive strategies for NSAID and aspirin-associated gastrointestinal bleeding should be directed toward preventing both upper and lower gastrointestinal damage. Future research should be directed toward identifying patients at low-risk for gastrointestinal events associated with the use of NSAIDs or aspirin to avoid inappropriate PPI prescribing. Alternatively, the efficacy of new pharmacologic strategies should be evaluated in high-risk groups, with the aim of reducing the risk of both upper and lower gastrointestinal bleeding in these patients.

Genetic ablation or pharmacologic inhibition of autophagy mitigated NSAID-associated gastric damages

Non-steroidal anti-inflammatory drug (NSAID)-associated endoplasmic reticulum (ER) stress (a cyclooxygenase-2-independent mechanism) and consequent autophagic cell death are responsible for NSAID-associated gastric damage. Therefore, alleviating cytotoxicity executed via ER stress and autophagy can be a strategy to prevent NSAID-associated gastric damage. Here, we explored whether genetic or pharmacologic inhibition of autophagy can mitigate NSAID-associated gastric damage in in vitro and in vivo models. To examine the effects of genetic inhibition of NSAID-associated autophagy, we administered indomethacin to RGM1 gastric mucosal cells transfected with shPERK, siLC3B, or shATG5 and microtubule-associated protein light chain 3B knock-out (LC3B^-/-) mice. 3-Methyladenine (3-MA) or chloroquine (CQ) was used for pharmacologic inhibition of autophagy in both models. Indomethacin administration increased the expression of ER stress proteins including GRP78, ATF6, and CHOP. Indomethacin provoked the appearance of autophagic vesicles with the increased expression of ATG5 and LC3B-II. Genetic ablation of various ER stress genes significantly attenuated indomethacin-induced autophagy and apoptosis (p < 0.01), whereas knock-down of either ATG5 or LC3B significantly reduced indomethacin-induced cytotoxicity (p < 0.01). Testing each of the genes implicated in ER stress and autophagy showed that indomethacin leads to gastric cell apoptosis through autophagy induction consequent to ER stress. Pharmacological inhibition of autophagy with either 3-MA or CQ in rats or genetic ablation of LC3B in mice all had a significant rescuing effect against indomethacin-associated gastric damage (p < 0.01) and a decrease in molecular markers of autophagic and apoptotic gastric cells. In conclusion, preemptive autophagy inhibition can be a potential strategy to mitigate NSAID-associated gastric damage.

KEY MESSAGES

NSAID administration triggered ER stress and subsequent autophagy. Inhibition of autophagy resulted in attenuated NSAID-associated cytotoxicity. Autophagy inhibitors represent a novel strategy to prevent NSAID-associated gastric damage.

In vivo effects of s-pantoprazole, polaprenzinc, and probiotic blend on chronic small intestinal injury induced by indomethacin

Treatment and prevention methods for non-steroidal anti-inflammatory drug-induced enteropathy have not yet been established. We tested the preventive effects of s-pantoprazole sodium trihydrate (PAN), polaprezinc (PZ), and probiotics on an indomethacin (Indo)-induced small intestinal injury in a rat model. Rats were randomised into 6 groups to receive: normal saline (control), Indo (6 mg/kg), PZ plus Indo, PAN plus Indo, or probiotics plus Indo (at 108 and 109 cfu/head) for 2 weeks. We measured body weight, food intake, severity of small intestinal damage, haemoglobin (Hb) levels in the small intestinal fluid, intestinal inflammatory cytokines, and a few groups of faecal bacteria. The experimental groups were found to have the following survival rates: 0% for the Indo, PZ, and PAN groups; 50% for both probiotic groups; and 100% for control. Treatment with probiotics of different concentrations reduced small intestinal lesion scores and intestinal fluid Hb as compared with the Indo group, while these parameters did not reduce in the PZ and PAN groups. The anti-inflammatory marker interleukin 10 increased in both probiotic groups. Analysis of a few groups of faecal bacteria revealed that Indo-induced a significant increase in Gram-negative bacteria and decreases in Bifidobacterium and Lactobacillus. Similar changes were also observed in the PZ and PAN groups. However, opposite effects were found in both probiotic groups. The use of probiotics appeared to be beneficial in preventing Indo-induced chronic small intestinal injury.

Gata4 is critical to maintain gut barrier function and mucosal integrity following epithelial injury

The intestinal epithelial barrier is critical to limit potential harmful consequences from exposure to deleterious luminal contents on the organism. Although this barrier is functionally important along the entire gut, specific regional regulatory mechanisms involved in the maintenance of this barrier are poorly defined. Herein, we identified Gata4 as a crucial regulator of barrier integrity in the mouse proximal intestinal epithelium. Conditional deletion of Gata4 in the intestine led to a drastic increase in claudin-2 expression that was associated with an important increase of gut barrier permeability without causing overt spontaneous inflammation. Administration of indomethacin, a non-steroidal anti-inflammatory drug (NSAID) that causes enteritis, led to rapid and restricted proximal small intestinal injuries in Gata4 mutant mice as opposed to control mice. Comparative analysis of gene transcript profiles from indomethacin-challenged control and Gata4 mutant mice identified defects in epithelial cell survival, inflammatory cell recruitment and tissue repair mechanisms. Altogether, these observations identify Gata4 as a novel crucial regulator of the intestinal epithelial barrier and as a critical epithelial transcription factor implicated in the maintenance of proximal intestinal mucosal integrity after injury.

Uncovering the uncertainty: Risk factors and clinical relevance of P1 lesions on small bowel capsule endoscopy of anemic patients

AIM

To identify risk factors for P1 lesions on small bowel capsule endoscopy (SBCE) and to describe the natural history of anemic patients with such type of lesions.

METHODS

One hundred patients were consecutively selected for a case-control analysis performed between 37 cases with P1 lesions and 63 controls with negative SBCE. Age, gender, comorbidities and regular medication were collected. Rebleeding, further investigational studies and death were also analyzed during the follow-up.

RESULTS

No significant differences on gender, median age or Charlson index were found between groups. Although no differences were found on the use of proton pump inhibitors, acetylsalicylic acid, anticoagulants or antiplatelet agents, the use of non-steroidal anti-inflammatory drugs (NSAID) was associated with a higher risk of P1 lesions (OR = 12.00, 95%CI: 1.38-104.1). From the 87 patients followed at our center, 39 were submitted to additional studies for investigation of iron-deficiency anemia (IDA), and this was significantly more common in those patients with no findings on SBCE (53.7% vs 30.3%, P = 0.033). A total of 29 patients had at least one rebleeding or IDA recurrence episode and 9 patients died of non-anemia related causes but no differences were found between cases and controls.

CONCLUSION

P1 lesions are commonly found in patients with IDA submitted to SBCE. The use of NSAID seems to be a risk factor for P1 lesions. The outcomes of patients with P1 lesions do not differ significantly from those with P0 lesions or normal SBCE.

Determination of the adequate dosage of rebamipide, a gastric mucoprotective drug, to prevent low-dose aspirin-induced gastrointestinal mucosal injury

Small intestinal mucosal injury caused by low-dose aspirin is a common cause of obscure gastrointestinal bleeding. We aimed to investigate the protective effects and optimal dose of rebamipide for low-dose aspirin-induced gastrointestinal mucosal injury. In this prospective randomized trial, 45 healthy volunteers (aged 20–65 years) were included and divided into three groups. The groups received enteric-coated aspirin 100 mg (low-dose aspirin) plus omeprazole 10 mg (Group A: proton pump inhibitor group), low-dose aspirin plus rebamipide 300 mg (Group B: standard-dose group), or low-dose aspirin plus rebamipide 900 mg (Group C: high-dose group). Esophagogastroduodenoscopy and video capsule endoscopy were performed, and the fecal occult blood reaction and fecal calprotectin levels were measured before and two weeks after drug administration. Although the fecal calprotectin levels increased significantly in Group A, they did not increase in Groups B and C. The esophagogastroduodenoscopic and video capsule endoscopic findings and the fecal occult blood test findings did not differ significantly among the three groups. In conclusion, standard-dose rebamipide is sufficient for preventing mucosal injury of the small intestine induced by low-dose aspirin, indicating that high-dose rebamipide is not necessary.

Prescription drugs associated with false-positive results when using faecal immunochemical tests for colorectal cancer screening

BACKGROUND

The most common side effect in population screening programmes is a false-positive result which leads to unnecessary risks and costs.

AIMS

To identify factors associated with false-positive results in a colorectal cancer screening programme with the faecal immunochemical test (FIT).

METHODS

Cross-sectional study of 472 participants with a positive FIT who underwent colonoscopy for confirmation of diagnosis between 2013 and 2014. A false-positive result was defined as having a positive FIT (≥20μg haemoglobin per gram of faeces) and follow-up colonoscopy without intermediate/high-risk lesions or cancer.

RESULTS

Women showed a two-fold increased likelihood of a false-positive result compared with men (adjusted OR, 2.3; 95%CI, 1.5-3.4), but no female-specific factor was identified. The other variables associated with a false-positive result were successive screening (adjusted OR, 1.5; 95%CI, 1.0-2.2), anal disorders (adjusted OR, 3.1; 95%CI, 2.1-4.5) and the use of proton pump inhibitors (adjusted OR, 1.8; 95%CI, 1.1-2.9). Successive screening and proton pump inhibitor use were associated with FP in men. None of the other drugs were related to a false-positive FIT.

CONCLUSION

Concurrent use of proton pump inhibitors at the time of FIT might increase the likelihood of a false-positive result. Further investigation is needed to determine whether discontinuing them could decrease the false-positive rate.

Mitigation of indomethacin-induced gastrointestinal damages in fat-1 transgenic mice via gate-keeper action of ω-3-polyunsaturated fatty acids

Non-steroidal anti-inflammatory drugs (NSAIDs) damage the gastrointestinal (GI) epithelial cell membranes by inducing several signals through lipid raft organization after membrane incorporation, whereas ω-3 polyunsaturated fatty acids (PUFAs) relieve inflammation, reduce oxidative stress, and provide cytoprotection, consequent to lipid raft disorganization. Therefore, we hypothesized that ω-3 PUFAs can protect the GI from NSAID-induced damages by initiating the gatekeeper action of cell membranes, subsequent to anti-inflammatory and anti-oxidative actions. Administration of indomethacin (IND) leads to the formation of lipid rafts and activation of caveolin-1; however, no such observations were made upon co-administration of eicosapentaenoic acid (EPA) and IND. In addition, the EPA-induced lipid raft disorganization, caveolin-1 inactivation, and cellular cytotoxicity were inhibited when target cells were knocked-out using G-protein coupled receptor 120 (GPR 120). EPA significantly attenuated IND-induced oxidative damage and apoptosis. IND administration induced significant ulceration, bleeding, and oedema in the stomach or small intestine of wild-type (WT) mice; however, such severe damages to the GI significantly decreased in fat-1 transgenic (TG) mice (P < 0.001), which exhibited decreased cyclooxygenase-2 expression and apoptosis, decreased interleukin-1β and FAS concentrations, and increased heme oxygenase-1 concentration. Our study indicates that the gatekeeper function of ω-3 PUFAs improves GI safety when administered with NSAID.

Colchicine prevents NSAID-induced small intestinal injury by inhibiting activation of the NLRP3 inflammasome

The inflammasome is a large, multiprotein complex that consists of a nucleotide-binding oligomerization domain-like receptor (NLR), an apoptosis-associated speck-like protein containing a caspase recruitment domain, and pro-caspase-1. Activation of the inflammasome results in cleavage of pro-caspase-1 into cleaved caspase-1, which promotes the processing of pro-interleukin (IL)-1β into mature IL-1β. We investigated the effects of colchicine on non-steroidal anti-inflammatory drug (NSAID)-induced small intestinal injury and activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome. Colchicine treatment inhibited indomethacin-induced small intestinal injury by 86% (1 mg/kg) and 94% (3 mg/kg) as indicated by the lesion index 24 h after indomethacin administration. Colchicine inhibited the protein expression of cleaved caspase-1 and mature IL-1β, without affecting the mRNA expression of NLRP3 and IL-1β. Although treatment with recombinant IL-1β (0.1 μg/kg) did not change the severity of small intestinal damage, the preventive effects of colchicine were abolished by supplementation with the same dose of recombinant IL-1β. Indomethacin-induced small intestinal damage was reduced by 77%, as determined by the lesion index in NLRP3^−/− mice, and colchicine treatment failed to inhibit small intestinal damage in NLRP3^−/− mice. These results demonstrate that colchicine prevents NSAID-induced small intestinal injury by inhibiting activation of the NLRP3 inflammasome.

Clinical importance of nonsteroidal anti-inflammatory drug enteropathy: the relevance of tumor necrosis factor as a promising target

The pathogenesis of nonsteroidal anti-inflammatory drug (NSAID) enteropathy is still unclear, and consequently, there is no approved therapeutic strategy for ameliorating such damage. On the other hand, molecular treatment strategies targeting tumor necrosis factor (TNF) exerts beneficial effects on NSAID-induced intestinal lesions in rodents and rheumatoid arthritis patients. Thus, TNF appears to be a potential therapeutic target for both the prevention and treatment of NSAID enteropathy. However, the causative relationship between TNF and NSAID enteropathy is largely unknown. Currently approved anti-TNF agents are highly expensive and exhibit numerous side effects. Hence, in this review, the pivotal role of TNF in NSAID enteropathy has been summarized and plant-derived polyphenols have been suggested as useful alternative anti-TNF agents because of their ability to suppress TNF activated inflammatory pathways both in vitro and in vivo.

Small intestinal injury in NSAID users suffering from rheumatoid arthritis or osteoarthritis

The goal of this prospective study was to assess non-steroidal anti-inflammatory drug (NSAID)-induced enteropathy in patients with rheumatoid arthritis (RA) or osteoarthritis (OA) by means of non-invasive wireless capsule enteroscopy. A total of 143 patients (74 with RA, 69 with OA) treated with NSAIDs (>1 month) and 42 healthy volunteers were included. All subjects underwent capsule endoscopy, laboratory tests and filled in questionnaires. The severity of small bowel injury was graded as: mild (red spots or sporadic erosions), moderate (10–20 erosions) or severe (>20 erosions or ulcers). Capsule endoscopy identified small bowel lesions in 44.8 % of patients (mild 36.4 %, moderate 3.5 % and severe in 4.9 %). Mild non-specific lesions were found in 11.9 % healthy volunteers. There was a significantly higher prevalence of enteropathy in RA (56.8 %) compared to OA (31.9 %, p < 0.01). A significant difference between NSAID users (RA and OA) with and without enteropathy was observed in erythrocytes (p < 0.01), the leucocyte count (p < 0.05), haemoglobin (p < 0.05), haematocrit (p < 0.05), serum albumin (p < 0.01) and erythrocyte sedimentation rate (p < 0.05). No relationship was found between enteropathy and dyspepsia, gender or age. NSAID therapy is associated with a significant risk of small bowel injury. The risk is significantly higher in RA patients suggesting a possible influence of the underlying disease.

Trial registration number: DRKS00004940.

Long-Term Outcomes of NSAID-Induced Small Intestinal Injury Assessed by Capsule Endoscopy in Korea: A Nationwide Multicenter Retrospective Study

BACKGROUND/AIMS

We evaluated the long-term outcome and clinical course of patients of nonsteroidal anti-inflammatory drug (NSAID)-induced small intestinal injury by performing capsule endoscopy (CE).

METHODS

A multicenter retrospective study was conducted using data collected from the CE nationwide database registry, which has been established since 2002.

RESULTS

A total of 140 patients (87 males; mean age, 60.6±14.8 years) from the CE nationwide database registry (n=2,885) were diagnosed with NSAID-induced small intestinal injury and enrolled in our study. Forty-nine patients (35.0%) presented with a history of aspirin use and an additional 49 (35.0%) were taking NSAIDs without aspirin. The most prominent findings after performing CE were multiple ulcerations (n=82, 58.6%) and erosions or aphthae (n=32, 22.9%). During the follow-up period (mean, 15.9±19.0 months; range, 0 to 106 months), NSAID-induced small intestinal injury only recurred in six patients (4.3%). Older age and hypertension were positive predictive factors for recurrence.

CONCLUSIONS

These results suggest that the recurrence of NSAID-induced small bowel injury was not frequent in the presence of conservative treatment. Therefore, the initial diagnosis using CE and the medication history are important.