Risk factors for severe nonsteroidal anti-inflammatory drug-induced small intestinal damage

Sustained intestinal epithelial monolayer wound closure after transient application of a FAK-activating small molecule

M64HCl, which has drug-like properties, is a water-soluble Focal Adhesion Kinase (FAK) activator that promotes murine mucosal healing after ischemic or NSAID-induced injury. Since M64HCl has a short plasma half-life in vivo (less than two hours), it has been administered as a continuous infusion with osmotic minipumps in previous animal studies. However, the effects of more transient exposure to M64HCl on monolayer wound closure remained unclear. Herein, we compared the effects of shorter M64HCl treatment in vitro to continuous treatment for 24 hours on monolayer wound closure. We then investigated how long FAK activation and downstream ERK1/2 activation persist after two hours of M64HCl treatment in Caco-2 cells. M64HCl concentrations immediately after washing measured by mass spectrometry confirmed that M64HCl had been completely removed from the medium while intracellular concentrations had been reduced by 95%. Three-hour and four-hour M64HCl (100 nM) treatment promoted epithelial sheet migration over 24 hours similar to continuous 24-hour exposure. 100nM M64HCl did not increase cell number. Exposing cells twice with 2-hr exposures of M64HCl during a 24-hour period had a similar effect. Both FAK inhibitor PF-573228 (10 μM) and ERK kinase (MEK) inhibitor PD98059 (20 μM) reduced basal wound closure in the absence of M64HCl, and each completely prevented any stimulation of wound closure by M64HCl. Rho kinase inhibitor Y-27632 (20 μM) stimulated Caco-2 monolayer wound closure but no further increase was seen with M64HCl in the presence of Y-27632. M64HCl (100 nM) treatment for 3 hours stimulated Rho kinase activity. M64HCl decreased F-actin in Caco-2 cells. Furthermore, a two-hour treatment with M64HCl (100 nM) stimulated sustained FAK activation and ERK1/2 activation for up to 16 and hours 24 hours, respectively. These results suggest that transient M64HCl treatment promotes prolonged intestinal epithelial monolayer wound closure by stimulating sustained activation of the FAK/ERK1/2 pathway. Such molecules may be useful to promote gastrointestinal mucosal repair even with a relatively short half-life.

Unveiling the relationship between gut microbiota and heart failure: Recent understandings and insights

Gut microbiota, which comprises a broad range of bacteria inhabiting the human intestines, plays a crucial role in establishing a mutually beneficial relationship with the host body. Dysbiosis refers to the perturbations in the composition or functioning of the microbial community, which can result in a shift from a balanced microbiota to an impaired state. This alteration has the potential to contribute to the development of chronic systemic inflammation. Heart failure (HF) is a largely prevalent clinical condition that has been demonstrated to have variations in the gut microbiome, indicating a potential active involvement in the pathogenesis and advancement of the disease. The exploration of the complex interplay between the gut microbiome and HF presents a potential avenue for the discovery of innovative biomarkers, preventive measures, and therapeutic targets. This review aims to investigate the impact of gut bacteria on HF.

Bulbar and post-bulbar duodenal ulcers: characteristics based on location

OBJECTIVES

Most research on duodenal ulcers has focused on bulbar ulcers; details on post-bulbar ulcers remain largely unknown. This study was conducted to determine the characteristics of patients with post-bulbar duodenal ulcers depending on their location.

METHODS AND MATERIALS

We conducted a retrospective study of hospitalized patients newly diagnosed with duodenal ulcers on endoscopy at a tertiary referral center in Japan between April 2004 and March 2019. Five hundred fifty-one patients diagnosed with duodenal ulcers were extracted for analysis.

RESULTS

Ulcers were observed only in the bulbus in 383 cases, only in the post-bulbar duodenum in 82 cases, and were co-existing in both areas in 86 cases. The Bulbar group had less comorbidities and was more likely to have atrophic gastritis, while the Post-bulbar and Co-existing groups were more likely to be admitted for non-gastrointestinal conditions. Regular acid suppressant use was more common in the post-bulbar group than in the Bulbar group. Bulbar ulcers were associated with a shorter length of stay relative to post-bulbar and co-existing ulcers, but ulcer location was not an independent predictor of length of stay. Patients with co-existing bulbar and post-bulbar ulcers have characteristics similar to those with post-bulbar ulcers alone.

CONCLUSION

Patients with post-bulbar ulcers and those with co-existing bulbar and post-bulbar ulcers have different characteristics and outcomes relative to patients with bulbar ulcers.

Proton Pump Inhibitors Increase the Risk of Nonsteroidal Anti-inflammatory Drug-Related Small-Bowel Injury: A Systematic Review With Meta-analysis

INTRODUCTION

Conflicting results exist on the association between proton-pump inhibitor (PPI) and nonsteroidal anti-inflammatory drug (NSAID)-related small-bowel damage. The aim of this study was to determine whether PPIs increased the risk of NSAID-related small-bowel damage by meta-analysis.

METHODS

A systematic electronic search in PubMed, Embase, and Web of Science was conducted from the time the database was created until March 31, 2022, for studies reporting associations between PPI use and outcomes, including the endoscopy-verified prevalence of small-bowel injury, mean number of small-bowel injuries per patient, change in hemoglobin level, and risk of small-bowel bleeding in subjects taking NSAIDs. Meta-analytical calculations for odds ratio (OR) and mean difference (MD) were performed with the random-effects model and interpreted with 95% confidence intervals (CIs).

RESULTS

Fourteen studies comprising 1996 subjects were included. Pooled analysis demonstrated that concomitant use of PPIs significantly increased the prevalence and number of endoscopy-verified small-bowel injuries (prevalence: OR = 3.00; 95% CI: 1.74-5.16; number: MD = 2.30; 95% CI: 0.61-3.99) and decreased hemoglobin levels (MD = -0.50 g/dL; 95% CI: 0.88 to -0.12) in NSAID users but did not change the risk of small-bowel bleeding (OR = 1.24; 95% CI: 0.80-1.92). Subgroup analysis demonstrated that PPIs significantly increased the prevalence of small-bowel injury in subjects taking nonselective NSAIDs (OR = 7.05; 95% CI: 4.70-10.59, 4 studies, I 2 = 0) and COX-2 inhibitors (OR = 4.00; 95% CI: 1.18-13.60, 1 study, no calculated I 2 ) when compared with COX-2 inhibitors alone.

DISCUSSION

PPIs increased the risk of NSAID-related small-bowel damage, and the clinical significance of higher prevalence of small-bowel injuries should be studied in the future.

Is the microbiome the cause of irritable bowel syndrome and inflammatory bowel disease? Lessons to consider from odontology

BACKGROUND

A substantial amount of research is pointing to the disrupted microbiome and dysfunctional host-microbiome interaction as potential causes of Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). The true cause of the diseases is still not fully elucidated, and the various treatments used are not truly effective in the long run, especially for IBD, since a true cure is not known to exist. Treatment failure and surgery are common for IBD, many times leading to a perceived lower quality of life, not to mention the enormous cost for society for treatment up until that point and after. Although it is clear that the microbiome has a major role in the disease, it seems the majority of the research and treatments are still focused on treating and understanding the inflammation and not the primary cause of the inflammation in the first place. This was also the case for many decades in the search for the cause of periodontitis (PD) and gingivitis (GV), a destructive and non-destructive inflammatory disorder, respectively, the first resulting in loss of tissue supporting the teeth. There was much uncertainty and confusion until it was fully established that the microbiome was the cause. PD treatments primarily nowadays reflect the cause, i.e. the removal of microbes. There is no doubt, however, that the inflammatory pathways are important in both diseases and the purpose of this text is not to dispute this in respect to gastrointestinal disorders too. However, a different view on inflammation and associated disorders is explored to explain the nature of extraintestinal manifestations.

PURPOSE

The aim of this report is not to systematically fully review the literature to try to strengthen causality, as there are many reviews that explore the microbial aspects of IBS and IBD. Instead, the objective is to above all reflect on what has been learned in the field of odontology/stomatology and discuss relevant gastrointestinal research in order to propose tentative hypotheses and questions regarding IBS and IBD aetiology. Perhaps it could help soften the confusion regarding the microbial aetiology and dysbiosis concept, while guiding future research and treatments, primarily regarding microbial transplants, antibiotics, and diet.

"MURAL" model to predict bleeding from mural-based lesions in potential small bowel bleeding may improve diagnostic capability and decrease cost

In potential small bowel bleeding, video capsule endoscopy (VCE) is excellent to detect mucosal lesions, while mural-based lesions are better detected by computed tomography enterography (CTE). A predictive tool to identify mural-based lesions should guide selecting investigations. In this retrospective study, we developed and validated the "MURAL" model based on logistic regression to predicts bleeding from mural-based lesions. Cost-effectiveness analysis comparing diagnostic strategy among VCE, CTE, and MURAL model was performed. Of 296 patients, 196 and 100 patients were randomly included in the derivative and validation cohorts, respectively. The MURAL model comprises 5 parameters: age, presence of atherosclerosis, chronic kidney disease, antiplatelet use, and serum albumin level. The area under the receiver operating characteristic curve was 0.778 and 0.821 for the derivative and validation cohorts, respectively. At a cutoff value of 24.2%, the model identified mural-based lesions with 70% sensitivity and 83% specificity in the validation cohort. Cost-effectiveness analysis revealed that application of the MURAL model demonstrated a comparable missed lesion rate but had a lower missed tumor rate, and lower cost compared to VCE strategy. The model for predicting mural-based lesions provide some guidance in investigative decision-making, which may improve diagnostic efficiency and reduce costs.

Risk factors for small-intestinal mucosal breaks beyond aspirin

BACKGROUND AND AIM

There remains lots of unknowns for small intestinal mucosal breaks (SIMBs). The application of magnetic controlled capsule endoscope (MCCE) may provide a better understanding of SIMBs. The aim of our study was to investigate the prevalence and characteristics of SIMBs in the general population as well as risk factors for SIMBs other than aspirin.

METHODS

Clinical data on individuals who visited our institute between January 2019 and February 2021 for MCCE examination as a health check were collected and analyzed retrospectively. All study participants must have completed the small bowel inspection. Multivariate analysis was employed to reveal the independent risk factors for SIMBs.

RESULTS

A total of 1599 participants, 103 of whom were aspirin users, were finally included. The prevalence of SIMBs was 8.3% (132/1599) in all participants, with 36.9% (38/103) in aspirin users and 6.3% (94/1496) in non-aspirin users. The multivariate analysis showed that in addition to aspirin (OR: 6.17, 95% CI: 3.25-11.58), obesity (OR: 2.30, 95% CI: 1.38-3.92) and smoking (OR: 1.85, 95% CI: 1.56-3.20) were also independent risk factors for SIMBs. Jejunum involvement was more common in aspirin users (20/38, 52.6%), while ilium involvement was more common in non-aspirin users (58/94, 61.7%). Moderate SIMBs (erosions) were more common in aspirin users (17/38, 44.7%), while severe SIMBs (large erosions/ulcers) were more common in non-aspirin users (17/94, 18.1%).

CONCLUSIONS

The risk factors for SIMBs include aspirin as well as smoking and obesity, and the severity and distributive features of SIMBs differ between aspirin users and non-aspirin users.

NSAID-Associated Small Intestinal Injury: An Overview From Animal Model Development to Pathogenesis, Treatment, and Prevention

With the wide application of non-steroidal anti-inflammatory drugs (NSAIDs), their gastrointestinal side effects are an urgent health burden. There are currently sound preventive measures for upper gastrointestinal injury, however, there is a lack of effective defense against lower gastrointestinal damage. According to a large number of previous animal experiments, a variety of NSAIDs have been demonstrated to induce small intestinal mucosal injury in vivo. This article reviews the descriptive data on the administration dose, administration method, mucosal injury site, and morphological characteristics of inflammatory sites of various NSAIDs. The cells, cytokines, receptors and ligands, pathways, enzyme inhibition, bacteria, enterohepatic circulation, oxidative stress, and other potential pathogenic factors involved in NSAID-associated enteropathy are also reviewed. We point out the limitations of drug modeling at this stage and are also pleased to discover the application prospects of chemically modified NSAIDs, dietary therapy, and many natural products against intestinal mucosal injury.

Review article: drug-induced small bowel injury

BACKGROUND

Drug-induced gastrointestinal injury has been increasingly reported, but its exact incidence is not known. The small and large intestines represent the most affected sites of injury, accounting for 20%-40% of all gastrointestinal side effects.

AIM

To provide an updated literature review detailing medications linked to the development of small bowel injury.

METHODS

We conducted a literature search on PubMed from its inception to May 1, 2021. We included English-language original studies, meta-analyses, systematic reviews, review articles and case reports.

RESULTS

Drug-induced enteropathy can range from asymptomatic histological changes resulting in a subtle, self-limited disease to a chronic inflammatory condition mimicking inflammatory bowel disease, or bowel perforation. Endoscopy can demonstrate erythema, mucosal friability, oedema, erosions, ulcers or strictures in severe cases. Histology may include mucosal erosions and ulcerations, focal active enteritis, villous atrophy, epithelial apoptosis or necrotising enteritis. A well-established association has been found with the use of nonsteroidal anti-inflammatory drugs, immunosuppressants, chemotherapeutic agents, antibiotics, immunotherapies, etanercept and olmesartan. Possible associations have been reported with other biologic agents, medications used for glycemic control, antihypertensives, cholinesterase inhibitors, potassium and iron supplements, with conflicting data regarding contraceptives/hormonal therapy and isotretinoin.

CONCLUSION

Physicians should be aware of the manifestations of drug-induced enteropathy as early recognition can lead to prompt discontinuation of the offending therapy and, therefore, a reduced risk of future complications.

Can manipulation of gut microbiota really be transformed into an intervention strategy for cardiovascular disease management?

Recent advancement in manipulation techniques of gut microbiota either ex vivo or in situ has broadened its plausible applicability for treating various diseases including cardiovascular disease. Several reports suggested that altering gut microbiota composition is an effective way to deal with issues associated with managing cardiovascular diseases. However, actual translation of gut microbiota manipulation-based techniques into cardiovascular-therapeutic approach is still questionable. This review summarized the evidence on challenges, opportunities, recent development, and future prospects of gut microbiota manipulation for targeting cardiovascular diseases. Initially, issues associated with current cardiovascular diseases treatment strategy, association of gut microbiota with cardiovascular disease, and its influence on cardiovascular drugs were discussed, followed by applicability of gut microbiota manipulation as a cardiovascular disease intervention strategy along with its challenges and future prospects. Despite the fact that the gut microbiota is rugged, interventions like probiotics, prebiotics, synbiotics, fecal microbiota transplantation, fecal virome transplantation, antibiotics, diet changes, and exercises could manipulate it. Advanced techniques like administration of engineered bacteriophages and bacteria could also be employed. Intensive exploration revealed that if sufficiently controlled approach and proper monitoring were applied, gut microbiota could provide a compelling answer for cardiovascular therapy.

Effects of Colchicine on NSAID-Induced Severe Small Intestinal Damage: A Pilot Study

BACKGROUND

We previously reported that nonsteroidal anti-inflammatory drugs (NSAIDs) induced small intestinal damage through nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome-dependent interleukin-1β secretion in mice. Our further study demonstrated that colchicine, a therapeutic agent for gout, significantly suppressed NSAID-induced small intestinal damage by inhibiting NLRP3 inflammasome activation in mice. However, clinical efficacy of colchicine for NSAID-induced small intestinal damage has not been established.

OBJECTIVES

We examined the clinical efficacy of colchicine in patients with NSAID-induced severe small intestinal damage as an animal-to-human translational research.

METHODS

This is a single-center, single-arm, prospective pilot study. From February 2017 to March 2019, we performed video capsule endoscopy (VCE) to screen 10 patients who took NSAIDs continuously for more than 3 months, and 7 of those with severe small intestinal damage were enrolled. Participants were treated with oral colchicine 0.5 mg twice daily for 8 weeks and thereafter followed up with blood tests and VCE.

RESULTS

After 8 weeks of colchicine treatment, complete healing was achieved in 4 patients (57.1%), and the median number of small erosions decreased significantly from 7.0 (range, 5.0-10.5) to 0.0 (range, 0.0-2.3) (p = 0.031). One patient withdrew due to diarrhea, and 5 patients revealed slightly elevated liver enzymes during the study. No other adverse events including changes in blood tests and clinical symptoms were observed.

CONCLUSIONS

Colchicine treatment achieved a high rate of complete healing in patients with NSAID-induced severe small intestinal damage.

A novel gene associated with small bowel bleeding in patients taking low-dose aspirin

OBJECTIVE

We have previously revealed the clinical factors and genetic polymorphisms associated with gastrointestinal mucosal injury and bleeding, induced by low-dose aspirin (LDA). After performing genome-wide analysis of single nucleotide polymorphisms (SNPs) using the Drug Metabolizing Enzymes and Transporters (DMET) system among drug metabolism and transporter genes, certain SNPs were found to increase the risk for LDA-induced small bowel bleeding. The aim of this study was to identify the SNPs involved in LDA-induced small bowel bleeding.

SUBJECTS AND METHODS

Subjects were patients taking LDA, with small bowel bleeding diagnosed using capsule endoscopy. We investigated the clinical characteristics and the previously identified SNPs, that were examined by the DNA direct sequence method.

RESULTS

56 patients with bleeding and 410 controls taking LDA were enrolled. The risk factors associated with small bowel bleeding included smoking, cerebrovascular diseases, chronic renal failure, non-steroidal anti-inflammatory drug (NSAID) or anticoagulants combination, and two SNPs (CYP4F11 20043G>A (D446N) rs1060463, GSTP1 313A>G rs1695). After propensity score matching, GSTP1 rs1695 was significantly associated with small bowel bleeding.

CONCLUSION

The GSTP1 SNP may be a predictive marker for small bowel bleeding among patients taking LDA.

Protective role of resolvin D1, a pro-resolving lipid mediator, in nonsteroidal anti-inflammatory drug-induced small intestinal damage

Resolvin D1, a specialized pro-resolving lipid mediator produced from docosahexaenoic acid by 15- and 5-lipoxygenase, exerts anti-inflammatory effects driving to the resolution of inflammation. The present study aimed to elucidate its role in small intestinal damage induced by nonsteroidal anti-inflammatory drug (NSAID). Indomethacin was administered orally to C57BL/6J male mice, which were sacrificed 24 h later to collect small intestine specimens. Before administration of indomethacin, mice were subjected to intraperitoneal treatment with resolvin D1 or oral administration of baicalein, a 15-lipoxygenase inhibitor. Small intestinal damage induced by indomethacin was attenuated by pretreatment with resolvin D1. Furthermore, resolvin D1 reduced the gene expression levels of interleukin-1β, tumor necrosis factor-α, and CXCL1/keratinocyte chemoattractant. Conversely, the inhibition of 15-lipoxygenase activity by baicalein increased the expression of genes coding for these inflammatory cytokines and chemokine, leading to exacerbated small intestinal damage, and reduced the concentration of resolvin D1 in the small intestinal tissue. Exogenous treatment with resolvin D1 negated the deleterious effect of baicalein. 15-lipoxygenase was mainly expressed in the epithelium and inflammatory cells of the small intestine, and its gene and protein expression was not affected by the administration of indomethacin. Inhibition of the resolvin D1 receptor, lipoxin A4 receptor /formyl peptide receptor 2, by its specific inhibitors Boc-1 and WRW4 aggravated indomethacin-induced small intestinal damage. Collectively, these results indicate that resolvin D1 produced by 15-lipoxygenase contributes to mucoprotection against NSAID-induced small intestinal damage through its anti-inflammatory effect.

Gaseous Mediators as a Key Molecular Targets for the Development of Gastrointestinal-Safe Anti-Inflammatory Pharmacology

Non-steroidal anti-inflammatory drugs (NSAIDs) represent one of the most widely used classes of drugs and play a pivotal role in the therapy of numerous inflammatory diseases. However, the adverse effects of these drugs, especially when applied chronically, frequently affect gastrointestinal (GI) tract, resulting in ulceration and bleeding, which constitutes a significant limitation in clinical practice. On the other hand, it has been recently discovered that gaseous mediators nitric oxide (NO), hydrogen sulfide (H2S) and carbon monoxide (CO) contribute to many physiological processes in the GI tract, including the maintenance of GI mucosal barrier integrity. Therefore, based on the possible therapeutic properties of NO, H2S and CO, a novel NSAIDs with ability to release one or more of those gaseous messengers have been synthesized. Until now, both preclinical and clinical studies have shown promising effects with respect to the anti-inflammatory potency as well as GI-safety of these novel NSAIDs. This review provides an overview of the gaseous mediators-based NSAIDs along with their mechanisms of action, with special emphasis on possible implications for GI mucosal defense mechanisms.

Rebamipide ameliorates indomethacin-induced small intestinal damage and proton pump inhibitor-induced exacerbation of this damage by modulation of small intestinal microbiota

Non-steroidal anti-inflammatory drugs (NSAIDs) induce small intestinal damage. It has been reported that rebamipide, a mucoprotective drug, exerts a protective effect against NSAID-induced small intestinal damage; however, the underlying mechanism remains unknown. In this study, we investigated the significance of the small intestinal microbiota in the protective effect of rebamipide against indomethacin-induced small intestinal damage in mice. A comprehensive analysis of the 16S rRNA gene sequencing revealed an alteration in the composition of the small intestinal microbiota at the species level, modulated by the administration of rebamipide and omeprazole. The transplantation of the small intestinal microbiota of the mice treated with rebamipide suppressed the indomethacin-induced small intestinal damage. Omeprazole, a proton pump inhibitor, exacerbated the indomethacin-induced small intestinal damage, which was accompanied by the alteration of the small intestinal microbiota. We found that the transplantation of the small intestinal microbiota of the rebamipide-treated mice ameliorated indomethacin-induced small intestinal damage and the omeprazole-induced exacerbation of the damage. These results suggest that rebamipide exerts a protective effect against NSAID-induced small intestinal damage via the modulation of the small intestinal microbiota, and that its ameliorating effect extends also to the exacerbation of NSAID-induced small intestinal damage by proton pump inhibitors.

Gut Microbiota in NSAID Enteropathy: New Insights From Inside

As a class of the commonly used drugs in clinical practice, non-steroidal anti-inflammatory drugs (NSAIDs) can cause a series of adverse events including gastrointestinal injuries. Besides upper gastrointestinal injuries, NSAID enteropathy also attracts attention with the introduction of capsule endoscopy and double balloon enteroscopy. However, the pathogenesis of NSAID enteropathy remains to be entirely clarified. Growing evidence from basic and clinical studies presents that gut microbiota is a critical factor in NSAID enteropathy progress. We have reviewed the recent data about the interplay between gut microbiota dysbiosis and NSAID enteropathy. The chronic medication of NSAIDs could change the composition of the intestinal bacteria and aggravate bile acids cytotoxicity. Meanwhile, NSAIDs impair the intestinal barrier by inhibiting cyclooxygenase and destroying mitochondria. Subsequently, intestinal bacteria translocate into the mucosa, and then lipopolysaccharide released from gut microbiota combines to Toll-like receptor 4 and induce excessive production of nitric oxide and pro-inflammatory cytokines. Intestinal injuries present in the condition of intestinal inflammation and oxidative stress. In this paper, we also have reviewed the possible strategies of regulating gut microbiota for the management of NSAID enteropathy, including antibiotics, probiotics, prebiotics, mucosal protective agents, and fecal microbiota transplant, and we emphasized the adverse effects of proton pump inhibitors on NSAID enteropathy. Therefore, this review will provide new insights into a better understanding of gut microbiota in NSAID enteropathy.

The Role of Nutritional Factors and Intestinal Microbiota in Rheumatoid Arthritis Development

Evidence about the role of nutritional factors and microbiota in autoimmune diseases, and in rheumatoid arthritis (RA) in particular, has grown in recent years, however many controversies remain. The aim of this review is to summarize the role of nutrition and of the intestinal microbiota in the development of RA. We will focus on selected dietary patterns, individual foods and beverages that have been most consistently associated with RA or with the occurrence of systemic autoimmunity associated with RA. We will also review the evidence for a role of the intestinal microbiota in RA development. We propose that diet and digestive microbiota should be considered together in research, as they interact and may both be the target for future preventive interventions in RA.

Enhanced Analgesic Effects and Gastrointestinal Safety of a Novel, Hydrogen Sulfide-Releasing Anti-Inflammatory Drug (ATB-352): A Role for Endogenous Cannabinoids

Aims: The covalent linking of nonsteroidal anti-inflammatory drugs to a hydrogen sulfide (H₂S)-releasing moiety has been shown to dramatically reduce gastrointestinal (GI) damage and bleeding, as well as increase anti-inflammatory and analgesic potency. We have tested the hypothesis that an H₂S-releasing derivative of ketoprofen (ATB-352) would exhibit enhanced efficacy without significant GI damage in a mouse model of allodynia/hyperalgesia. Results: ATB-352 was significantly more potent and effective as an analgesic than ketoprofen and did not elicit GI damage. Pretreatment with an antagonist of the CB1 cannabinoid receptor (AM251) significantly reduced the analgesic effects of ATB-352. The CB1 antagonist exacerbated GI damage when coadministered with ketoprofen, but GI damage was not induced by the combination of ATB-352 and the CB1 antagonist. In vitro, ATB-352 was substantially more potent than ketoprofen as an inhibitor of fatty acid amide hydrolase, consistent with a contribution of endogenous cannabinoids to the analgesic effects of this drug. Blood anandamide levels were significantly depressed by ketoprofen, but remained unchanged after treatment with ATB-352. Innovation: Ketoprofen is a potent analgesic, but its clinical use, even in the short term, is significantly limited by its propensity to cause significant ulceration and bleeding in the GI tract. Covalently linking an H₂S-releasing moiety to ketoprofen profoundly reduces the GI toxicity of the drug, while boosting analgesic effectiveness. Conclusion: This study demonstrates a marked enhancement of the potency and effectiveness of ATB-352, an H₂S-releasing derivative of ketoprofen, in part, through the involvement of the endogenous cannabinoid system. This may have significant advantages for the control and management of pain, such as in a postoperative setting.

Current knowledge on non-steroidal anti-inflammatory drug-induced small-bowel damage: a comprehensive review

Recent advances in small-bowel endoscopy such as capsule endoscopy have shown that non-steroidal anti-inflammatory drugs (NSAIDs) frequently damage the small intestine, with the prevalence rate of mucosal breaks of around 50% in chronic users. A significant proportion of patients with NSAIDs-induced enteropathy are asymptomatic, but some patients develop symptomatic or complicated ulcers that need therapeutic intervention. Both inhibition of prostaglandins due to the inhibition of cyclooxygenases and mitochondrial dysfunction secondary to the topical effect of NSAIDs play a crucial role in the early process of injury. As a result, the intestinal barrier function is impaired, which allows enterobacteria to invade the mucosa. Gram-negative bacteria and endogenous molecules coordinate to trigger inflammatory cascades via Toll-like receptor 4 to induce excessive expression of cytokines such as tumor necrosis factor-α and to activate NLRP3 inflammasome, a multiprotein complex that processes pro-interleukin-1β into its mature form. Finally, neutrophils accumulate in the mucosa, resulting in intestinal ulceration. Currently, misoprostol is the only drug that has a proven beneficial effect on bleeding small intestinal ulcers induced by NSAIDs or low-dose aspirin, but its protection is insufficient. Therefore, the efficacy of the combination of misoprostol with other drugs, especially those targeting the innate immune system, should be assessed in the next step.

[NSAID enteropathy]

Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly used drugs in the world, and their side effects are very high. First of all, these are NSAID gastropathy, but in the long term, 5070% of NSAIDs cause damage to the small intestine (NSAID enteropathy), sometimes with serious consequences. To date, no drugs have been proposed with proven effectiveness to prevent this side effect. Apparently, this is not due to the fully clarified mechanism of pathogenesis. The most promising is the hypothesis of the participation of individual representatives of microflora in the development of enteropathy. Therefore, modulating the intestinal flora with the help of probiotics can be the basic therapeutic strategy for the prevention and treatment of such damage.

NSAID-Gut Microbiota Interactions

Nonsteroidal anti-inflammatory drugs (NSAID)s relieve pain, inflammation, and fever by inhibiting the activity of cyclooxygenase isozymes (COX-1 and COX-2). Despite their clinical efficacy, NSAIDs can cause gastrointestinal (GI) and cardiovascular (CV) complications. Moreover, NSAID use is characterized by a remarkable individual variability in the extent of COX isozyme inhibition, therapeutic efficacy, and incidence of adverse effects. The interaction between the gut microbiota and host has emerged as a key player in modulating host physiology, gut microbiota-related disorders, and metabolism of xenobiotics. Indeed, host-gut microbiota dynamic interactions influence NSAID disposition, therapeutic efficacy, and toxicity. The gut microbiota can directly cause chemical modifications of the NSAID or can indirectly influence its absorption or metabolism by regulating host metabolic enzymes or processes, which may have consequences for drug pharmacokinetic and pharmacodynamic properties. NSAID itself can directly impact the composition and function of the gut microbiota or indirectly alter the physiological properties or functions of the host which may, in turn, precipitate in dysbiosis. Thus, the complex interconnectedness between host-gut microbiota and drug may contribute to the variability in NSAID response and ultimately influence the outcome of NSAID therapy. Herein, we review the interplay between host-gut microbiota and NSAID and its consequences for both drug efficacy and toxicity, mainly in the GI tract. In addition, we highlight progress towards microbiota-based intervention to reduce NSAID-induced enteropathy.

High-fat diet-mediated dysbiosis exacerbates NSAID-induced small intestinal damage through the induction of interleukin-17A

Non-steroidal anti-inflammatory drugs (NSAIDs) cause damage in the small intestine in a bacteria-dependent manner. As high-fat diet (HFD) is a potent inducer of gut dysbiosis, we investigated the effects of HFD on bacterial flora in the small intestine and NSAID-induced enteropathy. 16S rRNA gene analysis revealed that the population of Bifidobacterium spp. significantly decreased by fold change of individual operational taxonomic units in the small intestine of mice fed HFD for 8 weeks. HFD increased intestinal permeability, as indicated by fluorescein isothiocyanate-dextran absorption and serum lipopolysaccharide levels, accompanied by a decrease in the protein expressions of ZO-1 and occludin and elevated mRNA expression of interleukin (IL)-17A in the small intestine. HFD-fed mice exhibited increased susceptibility to indomethacin-induced damage in the small intestine; this phenotype was observed in normal diet-fed mice that received small intestinal microbiota from HFD-fed mice. Administration of neutralizing antibodies against IL-17A to HFD-fed mice reduced intestinal permeability and prevented exacerbation of indomethacin-induced damage. Thus, HFD-induced microbial dysbiosis in small intestine caused microinflammation through the induction of IL-17A and increase in intestinal permeability, resulting in the aggravation of NSAID-induced small intestinal damage.

Gut Microbiome and Response to Cardiovascular Drugs

The gut microbiome is emerging as an important contributor to both cardiovascular disease risk and metabolism of xenobiotics. Alterations in the intestinal microbiota are associated with atherosclerosis, dyslipidemia, hypertension, and heart failure. The microbiota have the ability to metabolize medications, which can results in altered drug pharmacokinetics and pharmacodynamics or formation of toxic metabolites which can interfere with drug response. Early evidence suggests that the gut microbiome modulates response to statins and antihypertensive medications. In this review, we will highlight mechanisms by which the gut microbiome facilitates the biotransformation of drugs and impacts pharmacological efficacy. A better understanding of the complex interactions of the gut microbiome, host factors, and response to medications will be important for the development of novel precision therapeutics for targeting CVD.

NSAID-induced enteropathy: the current state of the problem

The review analyzes the main etiological and pathogenetic mechanisms of the development of NSAID-enteropathy. Particular attention is paid to the role of intestinal microbiota in the manifestation and progression of NSAID-enteropathy. The special role of probiotics in the prevention and treatment of NSAIDs enteropathy is considered.

Eicosanoids in the gastrointestinal tract

Eicosanoids play important roles in modulating inflammation throughout the body. The gastrointestinal (GI) tract, in part because of its intimate relationship with the gut microbiota, is in a constant state of low-grade inflammation. Eicosanoids like PGs, lipoxins and leukotrienes play essential roles in maintenance of mucosal integrity. On the other hand, in some circumstances, these mediators can become major drivers of inflammatory processes when the lining of the GI tract is breached. Drugs such as nonsteroidal anti-inflammatories, by altering the production of various eicosanoids, can dramatically impact the ability of the GI tract to respond appropriately to injury. Disorders such as inflammatory bowel disease appear to be driven in part by altered production of eicosanoids. Several classes of drugs have been developed that target eicosanoids. LINKED ARTICLES: This article is part of a themed section on Eicosanoids 35 years from the 1982 Nobel: where are we now? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.8/issuetoc.

Involvement of gliadin, a component of wheat gluten, in increased intestinal permeability leading to non-steroidal anti-inflammatory drug-induced small-intestinal damage

Gliadin, a component of wheat gluten known to be an important factor in the etiology of celiac disease, is related to several other diseases through its enhancing effect on intestinal paracellular permeability. We investigated the significance of gliadin in non-steroidal anti-inflammatory drug (NSAID)-induced small-intestinal damage in mice. 7-week-old C57BL/6 male mice were divided into the following groups: standard diet group, in which mice were fed with wheat-containing standard rodent diet (CE-2); gluten-free diet group, in which mice were fed with gluten-free diet (AIN-76A); and gliadin-administered group, in which mice fed with gluten-free diet were administered with gliadin (~250 mg/kg BW). Each group was subdivided into negative, healthy control group and NSAID-treated group. To some mice fed with gluten-free diet and administered with gliadin, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor was administered for clarification of the significance of EGFR in NSAID-induced small intestinal damage and intestinal permeability. In mice fed with a gluten-free diet, indomethacin or diclofenac induced very mild mucosal damage in the small intestine compared with that in mice fed with a wheat-containing standard diet. Gliadin exacerbated the NSAID-induced small-intestinal damage in mice fed with a gluten-free diet. With the administration of indomethacin, MPO activity, a marker of neutrophil infiltration into the mucosa and mRNA expression level of tumor necrosis factor α and interleukin-1β in the small intestine were higher in the gliadin-administered mice. Gliadin increased the intestinal paracellular permeability without indomethacin administration (4.3-fold) and further increased the permeability after indomethacin administration (2.1-fold). Gliadin induced phosphorylation of epidermal growth factor receptor (EGFR) in small-intestinal tissues, and erlotinib (an EGFR tyrosine kinase inhibitor) attenuated the indomethacin-induced intestinal damage and permeability exacerbated by gliadin, accompanied by inhibition of EGFR phosphorylation. These results suggest that gliadin plays an important role in the induction and exacerbation of NSAID-induced small-intestinal damage, and that increase in intestinal permeability via the EGFR signalling pathway is involved in its mechanism.

Pathophysiology of NSAID-Associated Intestinal Lesions in the Rat: Luminal Bacteria and Mucosal Inflammation as Targets for Prevention

Non-steroidal anti-inflammatory drugs (NSAIDs) can damage the small intestine, mainly through an involvement of enteric bacteria. This study examined the pathophysiology of NSAID-associated intestinal lesions in a rat model of diclofenac-enteropathy and evaluated the effect of rifaximin on small bowel damage. Enteropathy was induced in 40-week old male rats by intragastric diclofenac (4 mg/kg BID, 14 days). Rifaximin (delayed release formulation) was administered (50 mg/kg BID) 1 h before the NSAID. At the end of treatments, parameters dealing with ileal damage, inflammation, barrier integrity, microbiota composition, and TLR-NF-κB-inflammasome pathway were evaluated. In addition, the modulating effect of rifaximin on NLRP3 inflammasome was tested in an in vitro cell system. Diclofenac induced intestinal damage and inflammation, triggering an increase in tissue concentrations of tumor necrosis factor and interleukin-1β, higher expression of TLR-2 and TLR-4, MyD88, NF-κB and activation of caspase-1. In addition, the NSAID decreased ileal occludin expression and provoked a shift of bacterial phyla toward an increase in Proteobacteria and Bacteroidetes abundance. All these changes were counterbalanced by rifaximin co-administration. This drug was also capable of increasing the proportion of Lactobacilli, a genus depleted by the NSAID. In LPS-primed THP-1 cells stimulated by nigericin (a model to study the NLRP3 inflammasome), rifaximin reduced IL-1β production in a concentration-dependent fashion, this effect being associated with inhibition of the up-stream caspase-1 activation. In conclusion, diclofenac induced ileal mucosal lesions, driving inflammatory pathways and microbiota changes. In conclusion, rifaximin prevents diclofenac-induced enteropathy through both anti-bacterial and anti-inflammatory activities.

Dual antiplatelet therapy does not affect the incidence of low-dose aspirin-induced small intestinal mucosal injury in patients after percutaneous coronary intervention for coronary stenosis: a multicenter cross-sectional study

Although low-dose aspirin (LDA) is known to induce small intestinal mucosal injury, the effect of dual antiplatelet therapy (DAPT; LDA + clopidogrel) on small intestinal mucosa in patients after percutaneous coronary intervention (PCI) for coronary stenosis is unknown. Fifty-one patients with a history of PCI and LDA use were enrolled, and 45 eligible patients were analyzed. Patients were grouped based on DAPT (DAPT: n = 10 and non-DAPT: n = 35) and proton pump inhibitor (PPI) use (PPI user: n = 22 and PPI-free patients: n = 23) to compare small intestinal endoscopic findings. The relationship between LDA-use period and small intestinal endoscopic findings was also examined. Multivariate analysis was performed to identify risk factors for LDA-induced mucosal injury using age, sex, DAPT, PPI, gastric mucoprotective drug, and LDA-use period. The rate of small intestinal mucosal injury incidence did not significantly differ between DAPT and non-DAPT patients (50% vs 51.1%, respectively; p = 0.94), or PPI users and PPI-free patients (50% vs 52.2%, respectively; p = 0.88). Additionally, LDA-use period of ≤24 months (n = 15) yielded a significantly higher rate of small intestinal mucosal injury incidence than LDA-use period >24 months (n = 30) (80% vs 36.7%, respectively; p = 0.006). Multivariate analysis revealed that a LDA-use period of ≤24 months was a significant risk factor for small intestinal mucosal injury (odds ratio: 19.5, 95% confidence interval: 2.48–154.00, p = 0.005). Following PCI for coronary stenosis, neither DAPT nor PPI affected LDA-induced small intestinal mucosal injury. Moreover, patients who used LDA within the last 24 months were at a greater risk of small intestinal mucosal injury.

Microscopic colitis-microbiome, barrier function and associated diseases

Microscopic colitis (MC) is a chronic inflammatory bowel disease (IBD) with little in terms of endoscopic abnormalities and is frequently associated with other autoimmune diseases. The peak incidence of the disease is in middle aged or older populations, mostly females. The pathogenesis of MC is complex, multifactorial and poorly understood. Current concepts revolve around innate immunity or microbiome alterations as well as gut barrier dysfunction, all of which lead to the development of subtle inflammatory lesions in gut mucosa. The results of numerous basic and clinical studies involving molecular techniques as well as advanced endoscopic imaging revealed the important role of both intrinsic (e.g., hormonal) as well as extrinsic (e.g., NSAIDs and PPIs) factors in the modulation of gastrointestinal microbiome and MC pathogenesis. Capsule endoscopy as well confocal endomicroscopy imaging, alongside standard endoscopic techniques offer new tools in the evaluation of MC patients and allow their better stratification for novel treatment protocols based on modulation of gut microbiome and barrier function.

Isoliquiritigenin Ameliorates Indomethacin-Induced Small Intestinal Damage by Inhibiting NOD-Like Receptor Family, Pyrin Domain-Containing 3 Inflammasome Activation

Activation of the NOD-Like Receptor Family, Pyrin Domain-Containing 3 (NLRP3) inflammasome, which consists of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and pro-caspase-1, triggers pro-caspase-1 cleavage promoting the processing of pro-interleukin (IL)-1β into mature IL-1β, which is critical for the development of non-steroidal anti-inflammatory drug (NSAID)-induced enteropathy. We investigated the effects of isoliquiritigenin, a flavonoid derived from the roots of Glycyrrhiza species, on NSAID-induced small intestinal damage and the inflammasome activation. To induce enteropathy, mice were administered indomethacin by gavage with or without isoliquiritigenin pretreatment. Some mice received an intraperitoneal injection of recombinant murine IL-1β in addition to isoliquiritigenin and indomethacin. Indomethacin induced small intestinal damage and increased protein levels of cleaved caspase-1 and mature IL-1β in the small intestine. Treatment with 7.5 and 75 mg/kg isoliquiritigenin inhibited indomethacin-induced small intestinal damage by 40 and 56%, respectively. Isoliquiritigenin also inhibited the indomethacin-induced increase in cleaved caspase-1 and mature IL-1β protein levels, whereas it did not affect the mRNA expression of NLRP3, ASC, caspase-1, and IL-1β. Protection against intestinal damage in isoliquiritigenin-treated mice was completely abolished with exogenous IL-1β. NLRP3-/- and caspase-1-/- mice exhibited resistance to intestinal damage, and isoliquiritigenin treatment failed to inhibit the damage in NLRP3-/- and caspase-1-/- mice. Isoliquiritigenin prevents NSAID-induced small intestinal damage by inhibiting NLRP3 inflammasome activation.

Meta-analysis: proton pump inhibitors moderately increase the risk of small intestinal bacterial overgrowth

The use of proton pump inhibitors (PPIs) may potentially predispose to the development of small intestinal bacterial overgrowth (SIBO), but this association is controversial due to conflicting results from studies conducted to date. The aim of this meta-analysis was to evaluate the association between the use of PPIs and the risk of SIBO. We systematically searched the online PubMed, Embase, and Cochrane Library databases and Web of Science for relevant articles published up to November 2016. Two researchers identified and extracted data independent of each other. The pooled analysis was performed using the generic inverse-variance random-effects model. Subgroup and sensitivity analysis were conducted to assess the stability and heterogeneity of the pooled results. The risk of publication bias was evaluated by assessing for funnel plot asymmetry and by Egger's test and Begg's test. A total of 19 articles met the eligibility criteria for the meta-analysis, reporting on 7055 subjects. The pooled odds ratio (OR) showed a statistically significant association between increased risk of SIBO and PPI use (OR 1.71, 95% confidence interval 1.20-2.43). Subgroup analyses demonstrated an association between SIBO and PPI use in studies that employed small bowel aspirates culture and glucose hydrogen breath tests (GHBT) as diagnostic tests for SIBO. Our meta-analysis suggests that the use of PPI moderately increases the risk of SIBO, thereby highlighting the need for appropriate prescribing of PPIs.

Gastrointestinal bleeding associated with chronic excessive use overdosing with topical ketoprofen patch in elderly patient

PURPOSE

Topical ketoprofen patch has been developed to reduce the risk of systemic adverse effects such as gastrointestinal injury and renal toxicity.

MATERIALS AND METHODS

We reported here a case of lower intestinal bleeding associated with chronic excessive use of topical ketoprofen patch in an elderly patient.

RESULTS

A 74-year-old female visited to the outpatient clinic of the Gifu University Hospital and admitted thereafter. She had fecal occult blood and anemia. Enteroscopic examination showed several ulcerative lesions and a protruded lesion accompanied with redness in the small intestinal mucosa. She used 8 sheets of 20 mg ketoprofen patch every day for a long period to relieve pain in the shoulder, lower back and lower limb. She had no diseases that are related to the initiation of gastrointestinal bleeding, including infection, inflammatory bowel disease, autoimmune disease and malignant disease. Thus, the present lower intestinal bleeding was concluded to be due to the use of topical ketoprofen patch. The symptoms were recovered after cessation of the patch.

CONCLUSIONS

Extensive care should be taken to avoid ulcerative intestinal hemorrhage to elderly patients receiving multiple doses of non-steroidal anti-inflammatory drug patch for multiple days.

Clinical factors associated with positive capsule endoscopy findings in patients with obscure gastrointestinal bleeding: a single-center study

BACKGROUND

Capsule endoscopy (CE) is a useful tool for patients with obscure gastrointestinal bleeding (OGIB), but positive finding rate differs among trials, which may be attributable to the difference in patients' background.

OBJECTIVES

To evaluate the predictive factors associated with positive findings on CE.

METHODS

Consecutive patients with OGIB who underwent CE between March 2004 and May 2015 at a single university hospital were enrolled. Patients' clinical factors and CE data were reviewed retrospectively, and we evaluated the relationship between clinical factors and positive findings by univariate and multivariate logistic regression analyses.

RESULTS

Five hundred and seventy-eight patients were included in the analysis. Positive CE findings were obtained in 284 patients (49.1%). In multivariate analysis, low hemoglobin level (odds ratio (OR), 1.142 per 1 g/dL decrease; p < .001), Charlson comorbidity index (CCI) score (OR, 1.170 per 1 point increase; p = .002), and non-steroidal anti-inflammatory drug (NSAID) use (OR, 1.640; p = .044) were associated with an increased prevalence of positive findings. As for components of CCI, malignant tumor (OR, 1.839; p = .017) was associated with the positive findings.

CONCLUSIONS

OGIB patient with a low-hemoglobin level, complex and severe comorbidities, and NSAID use should receive CE.

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.

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.

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.

Is a fecal occult blood test a useful tool for judging whether to perform capsule endoscopy in low-dose aspirin users with negative colonoscopy and esophagogastroduodenoscopy?

BACKGROUND

Aspirin use is reportedly not to be associated with fecal immunochemical occult blood test (FIT) false-positive results for the detection of colorectal cancer. The need for additional small bowel exploration in FIT-positive, low-dose aspirin users with a negative colonoscopy is controversial. The aim of this study was to assess the ability of FIT to judge whether capsule endoscopy (CE) should be performed in low-dose aspirin users with negative colonoscopy and esophagogastroduodenoscopy findings by comparing FIT results with CE findings.

METHODS

A total of 264 consecutive low-dose aspirin users with negative colonoscopy and esophagogastroduodenoscopy who were scheduled to undergo CE at five hospitals in Japan were enrolled. Patients had been offered FIT prior to the CE. The association between the FIT results and the CE findings was then assessed.

RESULTS

One hundred and fifty-seven patients were included in the final analysis. Eighty-four patients (53.5 %) had positive FIT results. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of positive FIT results for small bowel ulcers were 0.56, 0.47, 0.30, and 0.73, respectively. Furthermore, the NPV of positive FIT results for severe small bowel injury (Lewis score ≥790) was markedly high (0.90). When the analysis was performed only in low-dose aspirin users with anemia, the sensitivity of the positive FIT results was notably improved (0.72).

CONCLUSIONS

Small bowel evaluation using CE is not recommended for FIT-negative, low-dose aspirin users. However, small bowel evaluation using CE should be considered in both FIT-positive and anemic low-dose aspirin users.

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.

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.

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.

Proton Pump Inhibitors Increase Incidence of Nonsteroidal Anti-Inflammatory Drug-Induced Small Bowel Injury: A Randomized, Placebo-Controlled Trial

BACKGROUND & AIMS

Some studies have reported a high incidence of small bowel injuries in 60%-80% of subjects who take nonselective nonsteroidal anti-inflammatory drugs and PPIs simultaneously. We performed a randomized, double-blind, controlled study to determine whether proton pump inhibitors (PPIs) exacerbate nonsteroidal anti-inflammatory drug-induced small bowel injury.

METHODS

Fifty-seven healthy subjects were randomly assigned groups given the cyclooxygenase (COX) 2 inhibitor celecoxib (200 mg, twice daily) plus placebo for 2 weeks (COX-2 + placebo group, n = 30), or celecoxib plus the PPI rabeprazole (20 mg, once daily) for 2 weeks (COX-2 + PPI group, n = 27). The study was performed from October 2012 through September 2013 at a tertiary medical center in Japan. All subjects were evaluated by capsule endoscopy at the start of the study and then after 2 weeks administration of celecoxib with rabeprazole or placebo. The incidence rates and the numbers of small bowel injuries (ulcers and erosions) that were observed under capsule endoscopy were compared between groups. The primary endpoint was the incidence of mucosal injuries at the second capsule endoscopy examination.

RESULTS

A significantly higher proportion of subjects in the COX-2 + PPI group developed small bowel injury (12 of 27 subjects; 44.4%) than in the COX-2 + placebo group (5 of 30 subjects; 16.7%; P = .04). Subjects in the COX-2 + PPI group had a significant increase in risk of small bowel injury compared with the COX-2 + placebo group (relative risk, 2.67; 95% confidence interval, 1.08-6.58). The number of erosions in each member of the COX-2 + PPI group was greater than in each member of the COX-2 + placebo group (P = .02). The number of ulcers did not differ between groups. Twenty-six percent of subjects in the COX-2 + PPI group developed mucosal injury in the jejunum, compared with none of the subjects in the COX-2 + placebo group (P = .003); no such trend was found in the ileum.

CONCLUSIONS

In a randomized, controlled trial, PPIs increased the risk of short-term nonsteroidal anti-inflammatory drug-induced small bowel injury. UMIN clinical trial registry number: UMIN000008883.