Prevention and management of non-steroidal anti-inflammatory drugs-induced small intestinal injury

DA-9601 has protective effects comparable to those of proton pump inhibitor and rebamipide against nonsteroidal anti-inflammatory drugs-induced upper and lower gastrointestinal bleeding in patients with rheumatoid arthritis: A nationwide study using Korean Health Insurance Review and Assessment Service database

DA-9601 extracted from Artemisia asiatica contains a bioactive compound - eupatilin - that can protect against gastric mucosal damage through anti-inflammatory and anti-oxidative properties and is approved for treating acute and chronic gastritis in Korea, but their ability to protect gastrointestinal (GI) bleeding caused by nonsteroidal anti-inflammatory drugs (NSAIDs) is unclear. We aimed to compare the protective effects of DA-9601 to those of proton pump inhibitors (PPI) and rebamipide against upper and lower GI bleeding in patients with rheumatoid arthritis (RA) undergoing long-term NSAIDs therapy using the Korean Health Insurance Review and Assessment database. In this nationwide retrospective cohort study, we evaluated patients with RA who concurrently received NSAIDs for >3 months with DA-9601, PPI, or rebamipide between January 2015 and December 2017. The index date was the date of NSAIDs initiation, and all patients were followed up until December 2020 to detect upper and lower GI bleeding. In total, 24,258 patients with RA were eligible, and 5468 (22.5%), 4417 (18.2%), and 14,373 (59.3%) received DA-9601, PPI, or rebamipide, respectively, on the index date. During follow-up, upper and lower GI bleeding occurred in 508 (2.1%) and 402 (1.6%) patients with RA, respectively. The incidence rate of upper and lower GI bleeding was 615/100,000 and 485/100,000 person-years, respectively. Among patients with RA receiving DA-9601, PPI, or rebamipide, the frequencies of NSAIDs-induced upper GI bleeding were 0.5%, 0.4%, and 1.2%, respectively. The frequencies of NSAIDs-induced lower GI bleeding were 0.4%, 0.4%, and 0.9%, respectively. The incidence of NSAIDs-induced upper GI bleeding in patients with RA receiving DA-9601, PPI, and rebamipide was 601/100,000, 705/100,000, and 596/100,000 person-years, respectively, while the incidence of NSAIDs-induced lower GI bleeding in the same groups was 449/100,000, 608/100,000, and 465/100,000 person-years, respectively. In the multivariate Cox regression analysis, no significant difference was observed in lower and upper GI bleeding hazards between patients with RA using DA-9601, PPI, and rebamipide. Our results suggest that DA-9601 may exhibit protection against NSAIDs-induced GI bleeding that is comparable to those of PPI and rebamipide in patients with RA.

Carprofen Attenuates Postoperative Mechanical and Thermal Hypersensitivity after Plantar Incision in Immunodeficient NSG Mice

Immunodeficient NSG mice are reported to be less responsive to buprenorphine analgesia. Here, we used NSG mice to compare the efficacy of the commonly used dose of carprofen (5 mg/kg) with 5 and 10 times that dose (25 and 50 mg/kg) for attenuating postoperative mechanical and thermal hypersensitivity following an incisional pain model. Male and female NSG mice (n = 45) were randomly assigned to one of 4 groups and received daily subcutaneous injections for 3 d: saline (5 mL/kg), 5 mg/kg carprofen (Carp5), 25 mg/kg carprofen (Carp25), and 50 mg/kg carprofen (Carp50). Mechanical and thermal hypersensitivity were assessed 24 h before and at 4, 24, and 48 h after surgery. Plasma carprofen concentrations were measured in a separate group of mice (n = 56) on days 0 (at 2, 4, 12, and 23 h), 1, and 2 after the first, second, and third doses, respectively. Toxicity was assessed through daily fecal occult blood testing (n = 27) as well as gross and histopathologic evaluation (n = 15). Our results indicated that the saline group showed both mechanical and thermal hypersensitivity throughout the study. Carp5 did not attenuate mechanical or thermal hypersensitivity at any time point. Carp25 attenuated mechanical and thermal (except for the 4-h time point) hypersensitivity. Carp50 attenuated only thermal hypersensitivity at 24 h. Fecal occult blood was detected in 1 of 8 Carp25-treated mice at 48 and 72 h. Histopathologic abnormalities (gastric ulceration, ulcerative enteritis, and renal lesions) were observed in some Carp50-treated mice. Plasma carprofen concentrations were dose and time dependent. Our results indicate that Carp25 attenuated postoperative mechanical and thermal hypersensitivity more effectively than Carp5 or Carp50 in NSG mice with incisional pain. Therefore, we recommend providing carprofen at 25 mg/kg SID for incisional pain procedures using immunodeficient NSG mouse.

Small Intestinal Perforation Caused by Enteric-coated Low-dose Aspirin

A 77-year-old man presented with abdominal pain for 1 week. He was taking enteric-coated low-dose aspirin (LDA) to prevent secondary cardiovascular events and a proton pump inhibitor (PPI). Computed tomography indicated a small intestinal perforation; thus, small intestine resection was performed. Two months after surgery, he experienced a recurrence of the perforation. Since his repeated perforation was suspected to be due to LDA, LDA was discontinued. He has experienced no further recurrence since then. This is the first case of small intestinal perforation caused by enteric-coated LDA. Enteric-coated LDA may cause small intestinal perforation in patients with severe atherosclerosis under PPI administration.

A novel drug-like water-soluble small molecule Focal Adhesion Kinase (FAK) activator promotes intestinal mucosal healing

Non-steroidal anti-inflammatory drugs (NSAIDs) injure the proximal and distal gut by different mechanisms. While many drugs reduce gastrointestinal injury, no drug directly stimulates mucosal wound healing. Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, induces epithelial sheet migration. We synthesized and evaluated a water-soluble FAK-activating small molecule, M64HCl, with drug-like properties. Monolayer wound closure and Western blots measured migration and FAK phosphorylation in Caco-2 ​cells, in vitro kinase assays established FAK activation, and pharmacologic tests assessed drug-like properties. 30 ​mg/kg/day M64HCl was administered in two murine small intestine injury models for 4 days. M64HCl (0.1-1000 ​nM) dose-dependently increased Caco-2 FAK-Tyr 397 phosphorylation, without activating Pyk2 and accelerated Caco-2 monolayer wound closure. M64HCl dose-responsively activates the FAK kinase domain vs. the non-salt M64, increasing the V_max of ATP-binding. Pharmacologic tests suggested M64HCl has drug-like properties and is enterally absorbed. M64HCl 25 ​mg/kg/day continuous infusion promoted healing of ischemic jejunal ulcers and indomethacin-induced small intestinal injury in C57Bl/6 mice. M64HCl-treated mice exhibited smaller ulcers 4 days after ischemic ulcer induction or indomethacin injury. Renal histology and plasma creatinine were normal. Mild hepatic inflammatory changes and ALT elevation were similar among M64HCl-treated mice and controls. M64HCl was concentrated in kidney and gastrointestinal mucosa and functional nephrectomy studies suggested predominantly urinary excretion. Little toxicity was observed in vitro or in single-dose mouse toxicity studies until >1000x higher than effective concentrations. M64HCl, a water-soluble FAK activator, promotes epithelial restitution and intestinal mucosal healing and may be useful to treat gut mucosal injury.

The effect of rebamipide on non-steroidal anti-inflammatory drug-induced gastro-enteropathy: a multi-center, randomized pilot study

BACKGROUND/AIMS

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly-used medications, and ailments such as arthritis or heart disease, require long-term use of these drugs, which can induce gastroenteropathy with bleeding and ulcers. This study investigated the associations between efficacy, safety, and gastrointestinal symptoms linked to rebamipide and proton pump inhibitor administration in patients requiring long-term NSAID use.

METHODS

This study was a multi-center, randomized, open-labeled, pilot design.

RESULTS

Thirty-three patients were included. Of these, 15 were included in the study group and 18 were in the control group. NSAID-induced gastric ulcers, which were the primary outcome of this study, did not occur in either the study or control group. Changes in the number of small bowel erosions and ulcers were -0.6 ± 3.06 in the study group and 1.33 ± 4.71 in the control group. The number of subjects with mucosal breaks (defined as multiple erosions and/or ulcers) was three (20%) in the study group and six (40%) in the control group (p = 0.427). No serious adverse events occurred in either group. However, dyspepsia and skin rashes occurred in six patients (31.58%) in the study group and 13 (65%) in the control group (p = 0.036).

CONCLUSION

Although statistically significant differences were not generated, possibly as a result of the small sample size, mucosal breaks observed via capsule endoscopy revealed that rebamipide was likely to be more effective than lansoprazole in preventing small intestine damage caused by NSAIDs. Furthermore, fewer side-effects emerged with rebamipide.

Opioid Use in Murine Model Results in Severe Gastric Pathology that May Be Attenuated by Proton Pump Inhibition

Opioids are the gold standard for chronic and acute pain management; however, their consequence on gastric function is relatively understudied. Opioid users have a higher incidence of gastric dysfunction, worse quality of life, increased hospitalizations, and increased use of antiemetic and pain modulator medications. The current study shows that morphine treatment in the murine model results in greater disruption of gastric epithelial cell morphology, increased gastric cell apoptosis, elevated inflammatory cytokines, and matrix metallopeptidase-9 secretion. Morphine treatment also increases gastric acid secretion and causes delays in gastric emptying. Moreover, morphine treatment causes an increase in systemic IL-6 level, which plays an important role in morphine-induced delayed gastric emptying and gastric damage. IL-6 knockout mice show a significant level of reduction in morphine-induced gastric delaying, acid retention, and gastric damage. Thus, morphine-mediated gastric damage is a consequence of the accumulation of acid in the stomach due to increased gastric acid secretion and delayed gastric emptying. Treatment with a proton pump inhibitor resulted in a significant reduction in morphine-induced gastric inflammation, gastric delaying, and improved morphine tolerance. Hence, these studies attribute morphine-mediated induction in gastric acidity and inflammatory cytokines as drivers for morphine-associated gastric pathology and show the therapeutic use of proton pump inhibitors as an inexpensive approach for clinical management of morphine-associated pathophysiology and analgesic tolerance.

Preventive effect of rebamipide on NSAID-induced lower gastrointestinal tract injury using FAERS and JADER

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for their antipyretic, analgesic, and anti-inflammatory properties. However, various aspects of NSAID-induced lower gastrointestinal tract injury remain unclear, and effective prophylaxis has not been established. Based on its pharmacological effect and clinical trials, rebamipide may prevent lower gastrointestinal tract injury, although this evidence is limited by the small scale of trials. The present study used the FDA Adverse Event Reporting System (FAERS) and the Japanese Adverse Event Reporting Database (JADER) to assess the efficacy of rebamipide in combination with loxoprofen and diclofenac in preventing NSAID-induced lower gastrointestinal tract injury. The calculated reporting odds ratio and 95% confidence interval (CI) for rebamipide in combination with loxoprofen and diclofenac were 1.15 (95% CI 0.88–1.51) and 1.28 (95% CI 0.82–2.01) for FAERS, and 0.50 (95% CI 0.35–0.71) and 0.43 (95% CI 0.27–0.67) for JADER, respectively. No signal was detected when combining drugs. These results suggest a prophylactic effect of rebamipide on NSAID-induced lower gastrointestinal tract injury.

Research progress of non-steroidal anti-inflammatory drug-induced small intestinal injury

Non-steroidal anti-inflammatory drugs (NSAIDs) are used widely around the world because of their anti-inflammatory, analgesic, and antiplatelet activity. However, long-term application of NSAIDs can lead to complications. Previously, the clinical attention was dedicated to the NSAID-induced upper gastrointestinal complications. Recently, the detection rate of small intestinal damage related to NSAIDs has increased due to the wide use of endoscopes such as capsule endoscopy and double-balloon colonoscopy. Although the majority of patients have no significant symptoms, there are still a small percentage of patients who develop obvious symptoms or complicated ulcers that require therapeutic intervention. Despite significant advances in our understanding of NSAIDs, the treatment modality and regimen for NSAID-induced small intestinal damage have remained relatively unclear. This article will provide a comprehensive overview of NSAID-induced small intestinal damage with regard to the epidemiology, clinical manifestations, diagnosis, risk factors, pathogenesis, and treatment, in order to provide informative evidence for clinical practice.

Anti-inflammatory effects of DA-9601, an extract of Artemisia asiatica, on aceclofenac-induced acute enteritis

DA-9601 is an extract obtained from Artemisia asiatica, which has been reported to have anti-inflammatory effects on gastrointestinal lesions; however, its possible anti-inflammatory effects on the small intestine have not been studied yet. Therefore, in this study, we investigated the protective effects of DA-9601 against the ACF-induced small intestinal inflammation. Inflammation of the small intestine was confirmed by histological studies and the changes in the CD4⁺ T cell fraction induced by the inflammation-related cytokines, and the inflammatory reactions were analyzed. Multifocal discrete small necrotic ulcers with intervening normal mucosa were frequently observed after treatment with ACF. The expression of IL-6, IL-17, and TNF-α genes was increased in the ACF group; however, it was found to have been significantly decreased in the DA-9601 treated group. In addition, DA-9601 significantly decreased the levels of proinflammatory mediators such as IL-1β, GM-CSF, IFN-γ, and TNF-α; the anti-inflammatory cytokine IL-10, on the other hand, was observed to have increased. It is known that inflammatory mediators related to T cell imbalance and dysfunction continuously activate the inflammatory response, causing chronic tissue damage. The fractions of IFN-γ⁺ Th1 cells, IL-4⁺ Th2 cells, IL-9⁺ Th9 cells, IL-17⁺ Th17 cells, and Foxp3⁺ Treg cells were significantly decreased upon DA-9601 treatment. These data suggest that the inflammatory response induced by ACF is reduced by DA-9601 via lowering of the expression of genes encoding the inflammatory cytokines and the concentration of inflammatory mediators. Furthermore, DA-9601 inhibited the acute inflammatory response mediated by T cells, resulting in an improvement in ACF-induced enteritis.

Efficacy of berberine in treatment of rheumatoid arthritis: From multiple targets to therapeutic potential

Rheumatoid arthritis is a systemic autoimmune disorder involved in persistent synovial inflammation. Berberine is a nature-derived alkaloid compound with multiple pharmacological activities in different pathologies, including RA. Recent experimental studies have clarified several determinant cellular and molecular targets of BBR in RA, and provided novel evidence supporting the promising therapeutic potential of BBR to combat RA. In this review, we recapitulate the therapeutic potential of BBR and its mechanism of action in ameliorating RA, and discuss the modulation of gut microbiota by BBR during RA. Collectively, BBR might be a promising lead drug with multi-functional activities for the therapeutic strategy of RA.

Non-steroidal anti-inflammatory drug-induced enteropathy as a major risk factor for small bowel bleeding: a retrospective study

Background

Small bowel (SB) bleeding accounts for 5% of all gastrointestinal (GI) bleeding cases and 80% of obscure GI bleeding cases. Although angioectasia is the common etiology of SB bleeding, nonsteroidal anti-inflammatory drug (NSAID)-induced SB lesions are also reported as a major cause in studies from Eastern countries. Herein, we assessed the frequency of occurrence of NSAID-induced SB lesions in Korean patients with obscure GI bleeding.

Methods

We retrospectively analyzed medical records of all consecutive patients aged ≥18 years who underwent capsule endoscopy from March 2018 to February 2019 at Ulsan University Hospital and Kosin University Gospel Hospital.

Results

Of the 83 subjects (all Korean; mean age ± standard deviation: 59 ± 18 years; age range: 18–84 years; men: n = 52; women: n = 31), 55 (66.2%) had stool with clear blood and 28 (33.8%) had normal stool with iron deficiency anemia. The detection rate of SB bleeding and lesions using capsule endoscopy was 72.3% (60 of 83 patients). A significantly higher frequency (40 of 51) of ulcerative/erosive lesions than other causes was observed in patients with inactive bleeding but visible SB lesions. As a result, NSAID-induced enteropathy accounted for 30.1% of 83 patients with obscure GI bleeding (25 of the all 60 SB bleeding cases).

Conclusions

Contrary to what is reported for patients in Western countries, this study in Korean patients showed an improved diagnostic yield of capsule endoscopy for obscure GI bleeding and that NSAID-induced enteropathy was the most common etiology of SB bleeding. Aggressive small intestine examination is required for patients with unexplained GI bleeding.

Glycomacropeptide Ameliorates Indomethacin-Induced Enteropathy in Rats by Modifying Intestinal Inflammation and Oxidative Stress

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is considered a serious and increasing clinical problem without available treatment. Glycomacropeptide (GMP) is a 64-amino acid peptide derived from milk κ-casein with numerous biological activities. The aim of this study was to investigate the protective effect of GMP on NSAID enteropathy in rats. Enteropathy was induced by seven days oral indomethacin administration. Rats were orally GMP treated from seven days previous and during the establishment of the enteropathy model. Changes in metabolism, hematological and biochemical blood alterations, intestinal inflammation and oxidative damage were analyzed. Integrity barrier markers, macroscopic intestinal damage and survival rate were also evaluated. GMP treatment prevented anorexia and weight loss in animals. Furthermore, prophylaxis with GMP ameliorated the decline in hemoglobin, hematocrit, albumin and total protein levels. The treatment had no therapeutic efficacy on the decrease of occludin and mucin (MUC)-2 expression in intestinal tissue. However, GMP markedly decreased neutrophil infiltration, and CXCL1, interleukin-1β and inducible nitric oxide synthase expression. Nitric oxide production and lipid hydroperoxide level in the small intestine were also diminished. These beneficial effects were mirrored by preventing ulcer development and increasing animal survival. These results suggest that GMP may protect against NSAID enteropathy through anti-inflammatory and antioxidant properties.

Natural polyphenols prevent indomethacin-induced and diclofenac-induced Caco-2 cell death by reducing endoplasmic reticulum stress regardless of their direct reactive oxygen species scavenging capacity

Objectives

Indomethacin (INDO) and diclofenac (DIC) can induce intestinal cell death through induction of oxidative stress-mediated ER stress and mitochondrial dysfunction. This study investigated the cytoprotective potential of 11 polyphenols, namely caffeic acid (CAF), curcumin (CUR), epigallocatechin gallate (EGCG), gallic acid (GAL), hypophyllanthin (HYPO), naringenin (NAR), phyllanthin (PHY), piperine (PIP), quercetin (QUE), rutin (RUT) and silymarin (SLY) against these two NSAIDs in Caco-2 cells.

Methods

Reactive oxygen species (ROS) production was determined with fluorescence spectroscopy using specific probes (DHE, DCFH-DA, HPF). Cell viability and mitochondrial function were assessed by MTT and TMRE assays. The mRNA levels of Bax, Bcl-2 and CHOP proteins were determined by quantitative real-time polymerase chain reaction technique.

Key findings

All test polyphenols reduced NSAIDs-mediated ROS production. Only EGCG, QUE and RUT protected INDO-/DIC-induced cell death. These three polyphenols suppressed Bax/Bcl-2 mRNA ratio, CHOP up-regulation and MMP disruption in NSAIDs-treated cells. CAF and NAR prevented cytotoxicity from INDO, but not DIC. The cytoprotective effect of NAR, but not CAF, involved alteration of Bax/Bcl-2 mRNA ratio or MMP disruption, but not CHOP transcription.

Conclusion

The cytoprotective activity of polyphenols against NSAIDs-induced toxicity stemmed from either suppression of CHOP-related ER and mitochondria stresses or other CHOP-independent pathways, but not from the intrinsic ROS scavenging capacity.

Nonsteroidal Anti-Inflammatory Drugs Prevent Vincristine-Dependent Cancer-Associated Fibroblasts Formation

Vincristine is used in the clinical treatment of colon cancer, especially in patients diagnosed in the advanced phase of cancer development. Unfortunately, similar to other agents used during antitumor therapy, vincristine might induce chemoresistance. Studies of this process focus mainly on the analysis of the molecular mechanisms within cancer, usually ignoring the role of stromal cells. Our present findings confirm that vincristine stimulates the secretion of tumor growth factors class beta and interleukin-6 from cancer-associated fibroblasts as a result of paracrine stimulation by cancer cells. Based on alterations in morphology, modulation of capillary formation, and changes in endothelial and mesenchymal marker profile, our findings demonstrate that higher levels of tumor growth factor-βs and interleukin-6 enhance cancer-associated fibroblast-like cell formation through endothelial–mesenchymal transition and that nonsteroidal anti-inflammatory drug treatment (aspirin and ibuprofen) is able to inhibit this phenomenon. The process appears to be regulated by the rate of microtubule polymerization, depending on β-tubulin composition. While higher levels of tubulin-β2 and tubulin-β4 caused slowed polymerization and reduced the level of factors secreted to the extracellular matrix, tubulin-β3 induced the opposite effect. We conclude that nonsteroidal anti-inflammatory drugs should be considered for use during vincristine monotherapy in the treatment of patients diagnosed with colorectal cancer.

A fatal case of bowel obstruction caused by non-steroidal anti-inflammatory drug enteropathy

We report the case of a 34-year-old woman who died after presenting to hospital with a 2-month history of vomiting, abdominal pain and diarrhea. Subsequent inquiries revealed that she had a history of non-steroidal anti-inflammatory drug (NSAID) abuse, and the autopsy revealed stricture formation consistent with being caused by NSAID enteropathy.

NSAIDs and the small bowel

PURPOSE OF REVIEW

The review describes the effects of NSAID gastrointestinal toxicity on the small bowel, wherein injury is as prevalent as in the gastroduodenum. This is well documented by capsule endoscopy, which also provides an endoscopic endpoint for novel treatment strategies.

RECENT FINDINGS

Appreciation of the prevalence of NSAID enteropathy has grown with capsule endoscopy and the use of composite end points that include obscure haemoglobin decreases in clinical studies. Along with dual cyclo-oxygenase isoform inhibition, gram-negative antigen presentation plays a role in the pathogenesis of NSAID enteropathy. The concomitant use of proton pump inhibitor (PPI) agents with both selective and nonselective NSAIDs in gastroduodenal protection exacerbates endoscopic enteropathy, which is thought to be due to intestinal dysbiosis. Strategies for small bowel mucosal protection include prostaglandin repletion and augmenting the intestinal flora.

SUMMARY

NSAID- related enteropathy is common and often presents subclinically. The most common presentation is anaemia, which may be less common in those on cyclo-oxygenase (COX)-2 inhibitors than nonselective NSAIDs. PPI use worsens NSAID enteropathy with more occult bleeding and ulceration and has been linked to gram-negative intestinal dysbiosis. If NSAID cessation is not possible, COX-2 inhibition without PPI therapy should be considered in patients with upper gastrointestinal risk factors. Mucoprotective agents such as misoprostol and rebamipide show promise and probiotics may have a future role.

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.

Is the use of AGILE patency capsule prior to videocapsule endoscopy useful in all patients with spondyloarthritis?

BACKGROUND AND AIMS

As already known, spondyloarthritis patients present a striking resemblance in intestinal inflammation with early Crohn's disease. Moreover, the frequent use of nonsteroidal anti-inflammatory drugs is an important part of their treatment. Both conditions could lead to intestinal stenoses. Therefore we proposed to investigate the usefulness of the patency capsule test in patients with spondyloarthritis.

MATERIAL AND METHODS

64 consecutive patients (33 males; mean age 38 ± 11 years) that fulfilled the AMOR criteria for seronegative spondyloarthropathy (59.4% ankylosing spondylitis) lacking symptoms or signs of intestinal stenosis were enrolled and submitted to an AGILE™ capsule patency test followed by a video capsule endoscopy (PillCam SB2™), as part of a protocol investigating the presence of intestinal inflammatory lesions. After reviewing the VCE recordings, the Lewis score (of small bowel inflammatory involvement) was computed.

RESULTS

In only 5 patients (7.8%) of the study group, the luminal patency test was negative. However, there was no retention of the videocapsule in any of the patients. From the 59 patients with a positive patency test, 3 patients presented single small bowel stenoses (two with ulcerated overlying inflamed mucosa, one cicatricial), all being traversed by the videocapsule along the length of the recording. None of the patients with a negative test had bowel stenoses. There was no correlation between the patency test and the Lewis score, the C reactive protein value, diagnosis of inflammatory bowel disease, or the family history of spondyloarthritis, psoriasis or inflammatory bowel disease.

CONCLUSION

The AGILE patency capsule does not seem to be a useful tool for all patients with spondyloarthritis prior to small bowel videocapsule endoscopy (ClinicalTrial.gov ID NCT 00768950).

Review article: a practical approach to the clinical management of NSAID enteropathy

Co-prescription of acid suppressive therapy, together with advances in small bowel imaging techniques, have shifted the burden of NSAID-related toxicity from gastro-duodenal to more distal small bowel injury. Due to predominantly subclinical disease, NSAID enteropathy remains under-recognised, with an incidence of 53-80% amongst healthy short-term users, and a prevalence of 50-71% following long-term (>3 months) use. Despite their distinct pathogenesis, those at risk of NSAID-related gastro-duodenal and small bowel complications share several risk factors. Clinical complications of NSAID enteropathy such as protein-losing enteropathy, small bowel strictures and diaphragm disease, confer significant morbidity, and are often irreversible. Small bowel prophylaxis has proven of modest efficacy after short-term, high-dose NSAID use in asymptomatic patients. While selective COX-2 inhibitors are associated with fewer gastro-duodenal complications relative to non-selective NSAIDs, their comparative benefit in protecting against small bowel enteropathy remains unclear. Prophylaxis should be considered in those at high risk of small bowel complications, as treatment options for established disease remain limited; however, the optimal agent remains unclear. We propose a clinical algorithm that may help prevent, monitor, investigate, and manage the sequelae of NSAID-induced small bowel toxicity.

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.

Evaluation of anti-inflammatory and ulcerogenic potential of zinc-ibuprofen and zinc-naproxen complexes in rats

Because of numerous indications and high availability, non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed and used medicines in the world. However, long-term therapy with and improper use of NSAIDs may lead to gastrointestinal damage. Therefore, improving the therapeutic index of the existing drugs has become a priority over the past decades. Considerable attention in the field has been concentrated on metal complexes of non-steroidal anti-inflammatory drugs. The aim of this study is to evaluate the effect of complexation with zinc on the anti-inflammatory and ulcerogenic effects of ibuprofen and naproxen after single and triple intragastric administration to rats. The anti-inflammatory effect was assessed in carrageenan-induced inflammatory edema in the hind paw of male albino Wistar rats. The mucosal lesions were inspected and evaluated for gross pathology. Single administration of both the investigated complexes, namely zinc-ibuprofen and zinc-naproxen (20 mg/kg equivalent to ibuprofen and naproxen, respectively) and their parent drugs and physical mixtures with zinc hydroaspartate (ZHA doses: 16.05 and 14.37 mg/kg), caused a significant reduction of the edema after the same time from the carrageenan injection in comparison to the control groups. However, no statistically significant differences between the investigated drugs were observed after their single administration. The mean ulceration score for the mixture of ibuprofen and ZHA was statistically lower than the mean score achieved in rats after treatment with ibuprofen alone. On the other hand, triple intragastric administration of the ZHA-ibuprofen and ZHA-naproxen combination showed substantial enhancement of the anti-inflammatory activity against control groups, as well as against the parent NSAIDs. The most potent anti-inflammatory activity was demonstrated after 2 h from the carrageenan injection in animals receiving ZHA together with naproxen. The edema growth was reduced in these animals by 80.9% as compared to the control group. This result was significantly higher than the results achieved in animals receiving zinc-naproxen (50.2%) or naproxen alone (47.9%). Both NSAID complexes with zinc and mixtures with ZHA alleviated ulcerations caused by parent NSAIDs; however, the mixtures of both ibuprofen and naproxen with ZHA after triple administration were the least damaging. In view of the above results, zinc supplementation during NSAID therapy may have a beneficial effect on ulcer prevention and healing by reducing the effective dose of the parent drug and increasing its potency.

Suppression of calpain expression by NSAIDs is associated with inhibition of cell migration in rat duodenum

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for the alleviation of pain and inflammation, but these drugs are also associated with a suite of negative side effects. Gastrointestinal (GI) toxicity is particularly concerning since it affects an estimated 70% of individuals taking NSAIDs routinely, and evidence suggests the majority of toxicity is occurring in the small intestine. Traditionally, NSAID-induced GI toxicity has been associated with indiscriminate inhibition of cyclooxygenase isoforms, but other mechanisms, including inhibition of cell migration, intestinal restitution, and wound healing, are likely to contribute to toxicity. Previous efforts demonstrated that treatment of cultured intestinal epithelial cells (IEC) with NSAIDs inhibits expression and activity of calpain proteases, but the effects of specific inhibition of calpain expression in vitro or the effects of NSAIDs on intestinal cell migration in vivo remain to be determined. Accordingly, we examined the effect of suppression of calpain protease expression with siRNA on cell migration in cultured IECs and evaluated the effects of NSAID treatment on epithelial cell migration and calpain protease expression in rat duodenum. Our results show that calpain siRNA inhibits protease expression and slows migration in cultured IECs. Additionally, NSAID treatment of rats slowed migration up the villus axis and suppressed calpain expression in duodenal epithelial cells. Our results are supportive of the hypothesis that suppression of calpain expression leading to slowing of cell migration is a potential mechanism through which NSAIDs cause GI toxicity.

Role of enterohepatic recirculation in drug disposition: cooperation and complications

Enterohepatic recirculation (EHC) concerns many physiological processes and notably affects pharmacokinetic parameters such as plasma half-life and AUC as well as estimates of bioavailability of drugs. Also, EHC plays a detrimental role as the compounds/drugs are allowed to recycle. An in-depth comprehension of this phenomenon and its consequences on the pharmacological effects of affected drugs is important and decisive in the design and development of new candidate drugs. EHC of a compound/drug occurs by biliary excretion and intestinal reabsorption, sometimes with hepatic conjugation and intestinal deconjugation. EHC leads to prolonged elimination half-life of the drugs, altered pharmacokinetics and pharmacodynamics. Study of the EHC of any drug is complicated due to unavailability of the apposite model, sophisticated procedures and ethical concerns. Different in vitro and in vivo methods for studies in experimental animals and humans have been devised, each having its own merits and demerits. Involvement of the different transporters in biliary excretion, intra- and inter-species, pathological and biochemical variabilities obscure the study of the phenomenon. Modeling of drugs undergoing EHC has always been intricate and exigent models have been exploited to interpret the pharmacokinetic profiles of drugs witnessing multiple peaks due to EHC. Here, we critically appraise the mechanisms of bile formation, factors affecting biliary drug elimination, methods to estimate biliary excretion of drugs, EHC, multiple peak phenomenon and its modeling.

Advances in research of non-steroidal anti-inflammatory drugs induced small intestinal injury

Non-steroidal anti-inflammatory drugs (NSAIDs) have anti-inflammatory, anti-pyretic and analgesic properties and have been widely used in clinical practice; however, they can cause cytotoxicity in the gastrointestinal tract, especially in the intestine. The injurious effects of NSAIDs on the small intestine occur frequently and can lead to severe clinical outcomes. A multifactorial etiology is involved in the pathogenesis of these lesions. Current studies found that, in addition to the suppression of cyclooxygenase activity, several factors including enterobacterial invasion, neutrophil migration, enterohepatic cycling of NSAIDs, bile and mitochondrial injury have been implicated in the pathogenesis of these lesions. This article reviews the mechanisms and therapeutic strategies in NSAIDs induced intestinal injury.

Safety and efficacy of paracetamol and NSAIDs in osteoarthritis: which drug to recommend?

INTRODUCTION

Osteoarthritis (OA) is the most common form of arthritis and is a major cause of disability, especially in people ≥ 45 years old. Several international societies recommend the use of both acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs) to alleviate OA pain. However, patients with OA often have comorbidities, notably cardiovascular risk factors, which may hamper the use of these analgesics.

AREAS COVERED

This paper reviews the safety of both acetaminophen and NSAIDs in OA. Recent data have pointed to a gastrointestinal and cardiovascular toxicity of acetaminophen, which has been neglected for a long time. In addition, several meta-analyses revealed that acetaminophen is a poor analgesic in OA. Traditional NSAIDs and cyclooxygenase 2 inhibitors (coxibs) have similar analgesic effects but vary greatly in their potential gastrointestinal and cardiovascular toxicity.

EXPERT OPINION

Given the putative gastrointestinal and cardiovascular toxicity and poor analgesic properties of acetaminophen in OA, its use in patients with risk factors is questionable. Acetaminophen should be used at the lowest effective dosage and for the shortest time in all OA patients. Given the different safety profiles, the choice of NSAIDs, traditional or coxibs, should be based on individual patient risk factors. A good knowledge of the different strategies to decrease the gastrointestinal and cardiovascular toxic effects of NSAIDs is key to the management of OA.

Delayed intestinal stricture following non-resectional treatment for non-occlusive mesenteric ischemia associated with hepatic portal venous gas: a case report

Background

Hepatic portal venous gas associated with non-occlusive mesenteric ischemia is indicative of a serious pathology that leads to bowel necrosis and it has a high mortality rate. Although non-occlusive mesenteric ischemia is acknowledged as a condition that requires early surgical treatment, it has been reported that bowel necrosis and surgical resection of the gangrenous lesion may be avoided if the condition is identified quickly and the cause is detected at an early phase. However, no reports or guidelines have been published that describe the management of patients in whom bowel necrosis and surgical treatment were avoided. We report the case of a patient who presented with non-occlusive mesenteric ischemia who was managed with non-resectional treatment at an early phase and had a delayed small-bowel stricture.

Case presentation

A 24-year-old man presented to the hospital with fever, abdominal pain, and vomiting. Abdominal computed tomography confirmed a diffuse gaseous distention with small-bowel pneumatosis and hepatic portal venous gas. An urgent laparotomy was performed, because septic shock associated with diffuse peritonitis and bowel necrosis was strongly suspected. Although we found purulent ascites and a perforated appendix at the time of surgery, gangrenous and transmural ischemic changes were not evident in the small bowel and colon. We performed an appendectomy without a bowel resection, and the patient was discharged on an oral diet. However, he was re-admitted to hospital, because 4 days after discharge he developed postoperative paralytic ileus. Non-operative management was chosen, but his symptoms did not improve. We decided to perform a laparotomy 40 days after the initial operation, and a considerable adhesion was detected. Therefore, only a synechotomy was performed. On day 57, he experienced symptoms that were associated with bowel obstruction once again. On day 59, a partial resection of the jejunum was performed. Severe luminal strictures were apparent within the jejunum, and marked structural changes were evident.

Conclusion

While non-surgical management can be chosen for selected patients with non-occlusive mesenteric ischemia, continuous observation to evaluate the development of delayed strictures that lead to bowel obstructions is required in patients who undergo non-resectional treatment.

The Effect of Combined Oxytocin-Misoprostol Versus Oxytocin and Misoprostol Alone in Reducing Blood Loss at Cesarean Delivery: A Prospective Randomized Double-Blind Study

PURPOSE

To compare the effect of combined oxytocin-misoprostol versus oxytocin and misoprostol alone in reducing blood loss at cesarean delivery.

METHODS

One hundred fifty patients of 18-40 years with singleton term pregnancies scheduled for cesarean section under spinal anesthesia were recruited in a prospective double-blind randomized clinical trial to one of the three following groups to receive 20 IU infusion of oxytocin (group O), 400-µg sublingual misoprostol tablets (group M) or 200-µg misoprostol plus 5 IU bolus intravenous oxytocin (group MO) after delivery. The hemoglobin level before surgery and 24 h after surgery, the need for additional oxytocic therapy, and the incidence of adverse effects were recorded.

RESULTS

The mean blood loss during surgery was significantly lower in group MO compared to other groups (P = 0.04). Comparison of mean arterial pressure (P = 0.38) and heart rate (P = 0.23) changes during spinal anesthesia and surgery failed to reveal any statistically significant differences between all groups through repeated measure analysis.

CONCLUSION

The use of combined lower dose of misoprostol-oxytocin significantly reduced the amount of blood loss during and after the lower segment cesarean section compared to higher dose of oxytocin and misoprostol alone, and its use was not associated with any serious side effects.

Spontaneous free perforation of the small intestine in adults

Spontaneous free perforation of the small intestine is uncommon, especially if there is no prior history of visceral trauma. However, free, even recurrent, perforation may complicate a defined and established clinical disorder, such as Crohn’s disease. In addition, free perforation may be the initial clinical presentation of an occult intestinal disorder, such as a lymphoma complicating celiac disease, causing diffuse peritonitis and an acute abdomen. Initial diagnosis of the precise cause may be difficult, but now has been aided by computerized tomographic imaging. The site of perforation may be helpful in defining a cause (e.g., ileal perforation in Crohn’s disease, jejunal perforation in celiac disease, complicated by lymphoma or collagenous sprue). Urgent surgical intervention, however, is usually required for precise diagnosis and treatment. During evaluation, an expanding list of other possible causes should be considered, even after surgery, as subsequent management may be affected. Free perforation may not only complicate an established intestinal disorder, but also a new acute process (e.g., caused by different infectious agents) or a longstanding and unrecognized disorder (e.g., congenital, metabolic and vascular causes). Moreover, new endoscopic therapeutic and medical therapies, including use of emerging novel biological agents, have been complicated by intestinal perforation. Recent studies also support the hypothesis that perforation of the small intestine may be genetically-based with different mutations causing altered connective tissue structure, synthesis and repair.

Efficacy of anakinra in gouty arthritis: a retrospective study of 40 cases

Introduction

Gout is a common arthritis that occurs particularly in patients who frequently have associated comorbidities that limit the use of conventional therapies. The main mechanism of crystal-induced inflammation is interleukin-1 production by activation of the inflammasome. We aimed to evaluate the efficacy and tolerance of anakinra in gouty patients.

Methods

We conducted a multicenter retrospective review of patients receiving anakinra for gouty arthritis. We reviewed the response to treatment, adverse events and relapses.

Results

We examined data for 40 gouty patients (32 men; mean age 60.0 ± 13.9 years) receiving anakinra. Mean disease duration was 8.7 ± 8.7 years. All patients showed contraindications to and/or failure of at least two conventional therapies. Most (36; 90%) demonstrated good response to anakinra. Median pain on a 100-mm visual analog scale was rapidly decreased (73.5 (70.0 to 80.0) to 25.0 (20.0 to 32.5) mm, P <0.0001), as was median C-reactive protein (CRP) level (130.5 (55.8 to 238.8) to 16.0 (5.0 to 29.5) mg/l, P <0.0001). After a median follow-up of 7.0 (2.0 to 13.0) months, relapse occurred in 13 patients after a median delay of 15.0 (10.0 to 70.0) days. Seven infectious events, mainly with long-term use of anakinra, were noted.

Conclusions

Anakinra may be efficient in gouty arthritis, is relatively well tolerated with short-term use, and could be a relevant option in managing gouty arthritis when conventional therapies are ineffective or contraindicated. Its long-term use could be limited by infectious complications.

Role of transient receptor potential vanilloid 4 activation in indomethacin-induced intestinal damage

Gastrointestinal ulcers and bleeding are serious complications of nonsteroidal anti-inflammatory drug (NSAID) use. Although administration of antibiotics and Toll-like receptor 4 knockdown mitigate NSAID-induced enteropathy, the molecular mechanism of these effects is poorly understood. Intestinal hyperpermeability is speculated to trigger the initial damage due to NSAID use. Transient receptor potential vanilloid 4 (TRPV4) is a nonselective cation channel expressed throughout the gastrointestinal tract epithelium that is activated by temperature, extension, and chemicals such as 5,6-epoxyeicosatrienoic acid (5,6-EET). The aim of this study was to investigate the possible role of TRPV4 in NSAID-induced intestinal damage. TRPV4 mRNA and protein expression was confirmed by RT-PCR and immunochemistry, respectively, in mouse and human tissues while TRPV4 channel activity of the intestinal cell line IEC-6 was assessed by Ca(2+)-imaging analysis. TRPV4 activators or the NSAID indomethacin significantly decreased transepithelial resistance (TER) in IEC-6 cells, and indomethacin-induced TER decreases were inhibited by specific TRPV4 inhibitors or small-interfering RNA TRPV4 knockdown, as well as by the epoxygenase inhibitor N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide, which decreased 5,6-EET levels. In TRPV4 knockout mice, indomethacin-induced intestinal damage was significantly reduced compared with WT mice. Taken together, these results show that TRPV4 activation in the intestinal epithelium caused epithelial hyperpermeability in response to NSAID-induced arachidonic acid metabolites and contributed to NSAID-induced intestinal damage. Thus, TRPV4 could be a promising new therapeutic target for the prevention of NSAID-induced intestinal damage.

Stercoral perforation in a child: a rare complication of NSAID use

The adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the gastrointestinal (GI) tract are well known. However, NSAID use rarely leads to a stercoral perforation, an extremely rare but life-threatening cause of acute abdomen. We present a case of stercoral sigmoid colon perforation in a 2-year-old girl, secondary to unintentional NSAID overdose, developing as a result of miscommunication between the general practitioner (GP) and the mother. To the best of our knowledge, stercoral perforation has never before been reported in a child.

Sarcomatoid carcinoma of the jejunum presenting as obscure gastrointestinal bleeding in a patient with a history of gliosarcoma

Small bowel malignant tumors are rare and sarcomatoid carcinomas have rarely been reported at this site. We report a 56-year-old woman, with history of an excised gliosarcoma, who presented with recurrent obscure gastrointestinal bleeding. She underwent endoscopy and colonoscopy, which failed to identify the cause of the bleeding. The abdominal computed tomography scan located a tumor in the small bowel. Pathology revealed a jejunal sarcomatoid carcinoma. She developed tumor recurrence and multiple liver metastases shortly after surgery. Immunohistochemistry is required for accurate diagnosis. Sarcomatoid carcinoma is a rare cause of obscure gastrointestinal bleeding, which is associated with a poor prognosis.

Intestinal and hepatic expression of cytochrome P450s and mdr1a in rats with indomethacin-induced small intestinal ulcers

BACKGROUND

Non-steroidal anti-inflammatory drugs induce the serious side effect of small intestinal ulcerations (SIUs), but little information is available regarding the consequences to drug metabolism and absorption.

AIM

We examined the existence of secondary hepatic inflammation in rats with indomethacin (INM)-induced SIUs and assessed its relationship to the cytochrome P450 (CYP) and P-glycoprotein (mdr1a), the major drug-metabolizing factors in the small intestine and the liver.

METHODS

Gene expression of the CYP family of enzymes and mdr1a was measured with quantitative real-time polymerase chain reaction (qPCR). Vancomycin (VCM), a poorly absorbed drug, was administered intraduodenally to rats with SIUs.

RESULTS

INM induced SIUs predominantly in the lower region of the small intestine with high expression of inflammatory markers. Liver dysfunction was also observed, which suggested a secondary inflammatory response in rats with SIUs. In the liver of rats with SIUs, the expression of CYP2C11, CYP2E1, and CYP3A1 was significantly decreased, and loss of CYP3A protein was observed. Although previous studies have shown a direct effect of INM on CYP3A activity, we could not confirm any change in hepatic CY3A4 expression (major isoform of human CYP3A) in vitro. The plasma VCM concentration was increased in rats with SIUs due to partial absorption from the mucosal injury, but not in normal mucosa.

CONCLUSIONS

INM-induced SIUs had a subtle effect on intestinal CYP expression, but had an apparent action on hepatic CYP, which was influenced, at least in part, by the secondary inflammation. Furthermore, drug absorption was increased in rats with SIUs.

Recent Advances in NSAIDs-Induced Enteropathy Therapeutics: New Options, New Challenges

The injurious effects of NSAIDs on the small intestine were not fully appreciated until the widespread use of capsule endoscopy. It is estimated that over two-thirds of regular NSAID users develop injury in the small intestinal injuries and that these injuries are more common than gastroduodenal mucosal injuries. Recently, chronic low-dose aspirin consumption was found to be associated with injury to the lower gut and to be a significant contributing factor in small bowel ulceration, hemorrhage, and strictures. The ability of aspirin and NSAIDs to inhibit the activities of cyclooxygenase (COX) contributes to the cytotoxicity of these drugs in the gastrointestinal tract. However, many studies found that, in the small intestine, COX-independent mechanisms are the main contributors to NSAID cytotoxicity. Bile and Gram-negative bacteria are important factors in the pathogenesis of NSAID enteropathy. Here, we focus on a promising strategy to prevent NSAID-induced small intestine injury. Selective COX-2 inhibitors, prostaglandin derivatives, mucoprotective drugs, phosphatidylcholine-NSAIDs, and probiotics have potential protective effects on NSAID enteropathy.

Rebamipide helps defend against nonsteroidal anti-inflammatory drugs induced gastroenteropathy: a systematic review and meta-analysis

BACKGROUND

Gastrointestinal toxicity of nonsteroidal anti-inflammatory drugs (NSAIDs) has been perplexing most clinicians and users of NSAIDs. Rebamipide is increasingly advocated as a candidate option for the prevention of NSAIDs induced gastrointestinal mucosal injury.

AIMS

To assess the efficacy and the safety of rebamipide for the prevention and treatment of NSAID-induced gastroenteropathy.

METHODS

PubMed, Embase, Web of Science, Google Scholar, the Cochrane Library, Japan Science and Technology Information Aggregator, and China Biology Medicine Disc were searched up to December 2011. Randomized controlled trials (RCTs) recruiting subjects with co-prescriptions of NSAIDs and rebamipide were eligible. Efficacy and safety of rebamipide were reevaluated, and dichotomous data were pooled to obtain relative risk (RR) with a 95 % confidence interval. Heterogeneity and publication bias were assessed by the inconsistency index statistic and funnel plot analysis, respectively.

RESULTS

The search identified 338 citations, and 15 RCTs including 965 individuals were eligible. In general, rebamipide acted better than placebo against short-term NSAID-induced gastroduodenal injury. Separate studies showed rebamipide was equal to or not superior to traditional strategies (including PPIs, H2RA and misoprostol treatment). Especially, rebamipide showed a beneficial effect against the small bowel damage (total RR = 2.70, 95 % confidence interval = 1.02-7.16, P = 0.045) when compared with placebo group. The average incidence of adverse events was about 36.1 % (0-70.0 %) but no serious event was recorded.

CONCLUSIONS

Current evidences show rebamipide is effective and safe for defending against NSAID-induced gastroduodenal and lower-gastrointestinal injuries. However, more well-designed trials should be conducted to fully confirm the practical value of rebamipide.

Mechanisms, prevention and clinical implications of nonsteroidal anti-inflammatory drug-enteropathy

This article reviews the latest developments in understanding the pathogenesis, detection and treatment of small intestinal damage and bleeding caused by nonsteroidal anti-inflammatory drugs (NSAIDs). With improvements in the detection of NSAID-induced damage in the small intestine, it is now clear that this injury and the associated bleeding occurs more frequently than that occurring in the stomach and duodenum, and can also be regarded as more dangerous. However, there are no proven-effective therapies for NSAID-enteropathy, and detection remains a challenge, particularly because of the poor correlation between tissue injury and symptoms. Moreover, recent studies suggest that commonly used drugs for protecting the upper gastrointestinal tract (i.e., proton pump inhibitors) can significantly worsen NSAID-induced damage in the small intestine. The pathogenesis of NSAID-enteropathy is complex, but studies in animal models are shedding light on the key factors that contribute to ulceration and bleeding, and are providing clues to the development of effective therapies and prevention strategies. Novel NSAIDs that do not cause small intestinal damage in animal models offer hope for a solution to this serious adverse effect of one of the most widely used classes of drugs.

The interplay between NSAIDs and Candida albicans on the gastrointestinal tract of guinea pigs

Recent studies suggest that Candida albicans colonization is associated with several gastrointestinal inflammatory disorders and is also responsible for the delay in ulcer healing. No data are reported about the effects of C. albicans on the nonsteroidal anti-inflammatory drugs (NSAIDs)-induced necroinflammatory lesions. On the other hand, beneficial effects of NSAIDs regarding the colonization potential with C. albicans have been reported. Our aim was to investigate whether the association between NSAIDs and C. albicans could potentially induce necroinflammatory lesions in the guinea pigs gastric and enteral mucosa. Three interventional groups of 11 guinea pigs each were investigated after 5 days of receiving indomethacin, C. albicans or the association of both. C. albicans and necroinflammatory lesions were graded based on histological examinations. Statistical analysis used Mann-Whitney nonparametric test. NSAIDs did not significantly decrease C. albicans colonization grades on gastrointestinal mucosa. Administration of indomethacin subsequent to C. albicans determined significantly more severe necroinflammatory lesions compared to group that only received C. albicans. The association of NSAIDs and C. albicans did not cause significantly more severe degenerative or inflammatory lesions compared to the administration of only NSAIDs in this experimental model. Associations between NSAIDs and C. albicans caused significantly more severe necroinflammatory injuries than the lesions produced by C. albicans, without enhancing the mucosal injury or inflammation caused by NSAIDs.

Internal frontier: The pathophysiology of the small intestine

Even though the small intestine occupies a major portion of the abdominal space and is essential for life, in most pathology textbooks any chapter on small intestinal diseases, especially in human beings, is typically shorter than those for other gastrointestinal organs. Clinical and experimental investigations of the small intestine in various clinical situations, such as nutrition management, obesity interventions, and emergency care, have elucidated several important biological problems associated with the small intestine, the last frontier of gastroenterology. In this issue, a review by Professor Basson and his team at Michigan State University sheds light on the changes in the human small intestine under various conditions based on their clinical and surgical experience. With the advent of recent innovations in enteroscopy, a form of endoscopy used to examine deep within the small intestine, the issue that they highlighted, i.e., mucosal adaptation and atrophy of the human small intestine, has emerged as a major and manageable challenge for gastroenterologists in general, including the readers of the World Journal of Gastroenterology.

Multiple NSAID-induced hits injure the small intestine: underlying mechanisms and novel strategies

Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause serious gastrointestinal (GI) injury including jejunal/ileal mucosal ulceration, bleeding, and even perforation in susceptible patients. The underlying mechanisms are largely unknown, but they are distinct from those related to gastric injury. Based on recent insights from experimental models, including genetics and pharmacology in rodents typically exposed to diclofenac, indomethacin, or naproxen, we propose a multiple-hit pathogenesis of NSAID enteropathy. The multiple hits start with an initial pharmacokinetic determinant caused by vectorial hepatobiliary excretion and delivery of glucuronidated NSAID or oxidative metabolite conjugates to the distal small intestinal lumen, where bacterial β-glucuronidase produces critical aglycones. The released aglycones are then taken up by enterocytes and further metabolized by intestinal cytochrome P450s to potentially reactive intermediates. The "first hit" is caused by the NSAID and/or oxidative metabolites that induce severe endoplasmic reticulum stress or mitochondrial stress and lead to cell death. The "second hit" is created by the significant subsequent inflammatory response that would follow such a first-hit injury. Based on these putative mechanisms, strategies have been developed to protect the enterocytes from being exposed to the parent NSAID and/or oxidative metabolites. Among these, a novel strategy already demonstrated in a murine model is the selective disruption of bacteria-specific β-glucuronidases with a novel small molecule inhibitor that does not harm the bacteria and that alleviates NSAID-induced enteropathy. Such mechanism-based strategies require further investigation but provide potential avenues for the alleviation of the GI toxicity caused by multiple NSAID hits.

Non-steroidal anti-inflammatory drugs-induced small intestinal injury and probiotic agents

Intestinal bacteria play a role in the development of non-steroidal anti-inflammatory drugs (NSAID)-induced small intestinal injury. Agents such as probiotics, able to modify the gut ecology, might theoretically be useful in preventing small intestinal damage induced by NSAIDs. The clinical studies available so far do suggest that some probiotic agents can be effective in this respect.