Rebamipide has the potential to reduce the intensity of NSAID-induced small intestinal injury: a double-blind, randomized, controlled trial evaluated by capsule endoscopy

Drugs Effective for Nonsteroidal Anti-inflammatory Drugs or Aspirin-induced Small Bowel Injuries: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

The frequency of small bowel (SB) injuries has increased due to the increased use of nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin. This study was a systematic review and meta-analysis to compare drugs effective for SB injuries caused by NSAIDs or aspirin use.

METHODS

We searched MEDLINE, Embase, and Cochrane registries for randomized controlled trials through February 2023. The extracted data included changes in the number of erosions or ulcers in the jejunum or ileum observed through capsule endoscopy in patients taking NSAIDs or aspirin and administration of various mucoprotectants. We investigated the therapeutic or preventive efficacy of these drugs. The methodological bias was evaluated using Risk of Bias 2.0.

RESULTS

Eighteen randomized controlled trials of drugs effective for NSAIDs or aspirin-induced SB injuries were included and analyzed. The agents used to treat or prevent SB injuries were rebamipide, misoprostol, geranylgeranylacetone, and probiotics. In the meta-analysis, the mucoprotectants that showed a significant effect in treating NSAID users, who developed SB injuries, were misoprostol (mean difference: -9.88; 95% CI: -13.26 to -6.50). Meanwhile, the mucoprotectant that can prevent SB injuries caused by NSAIDs or aspirin in the general population was rebamipide (mean difference: -1.85; 95% CI: -2.74 to -0.96).

CONCLUSIONS

Misoprostol was effective in treating SB injuries caused by NSAIDs or aspirin (CRD42023410946).

Continuous co-prescription of rebamipide prevents upper gastrointestinal bleeding in NSAID use for orthopaedic conditions: A nested case-control study using the LIFE Study database

BACKGROUND

Rebamipide has been widely co-prescribed with non-steroidal anti-inflammatory drugs (NSAIDs) in Japan for decades. This study aimed to evaluate the effectiveness of rebamipide in preventing upper gastrointestinal bleeding in new users of NSAIDs without risk factors of NSAID-induced ulcers other than age.

METHODS

A nested case-control study was conducted using medical claims data of 1.66 million inhabitants of 17 municipalities participating in Japan's Longevity Improvement & Fair Evidence study. The cohort entry (t0) corresponded to a new user of NSAIDs for osteoarthritis or low back pain. Patients with risk factors of NSAID-induced ulcers other than age were excluded. Cases were defined as patients who underwent gastroscopy for upper gastrointestinal bleeding (occurrence date was defined as index date). A maximum of 10 controls were selected from non-cases at the index date of each case by matching sex, age, follow-up time, and type and dosage of NSAIDs. Exposure to rebamipide was defined as prescription status from t0 to index date: Non-user (rebamipide was not co-prescribed during the follow-up period), Continuous-user (rebamipide was co-prescribed from t0 with the same number of tablets as NSAIDs), and Irregular-user (neither Non-user nor Continuous-user). Conditional logistic regression analysis was conducted to estimate each category's odds ratio compared to non-users.

FINDINGS

Of 67,561 individuals who met the inclusion criteria, 215 cases and 1,516 controls were selected. Compared with that of Non-users, the odds ratios and 95% confidence interval were 0.65 (0.44-0.96) for Continuous-users and 2.57 (1.73-3.81) for Irregular-users.

CONCLUSIONS

Continuous co-prescription of rebamipide significantly reduced the risk of upper gastrointestinal bleeding in an Asian cohort of new users of NSAIDs with osteoarthritis or low back pain without risk factors other than age.

A real-world disproportionality analysis of the FDA adverse event reporting system events for ibuprofen

INTRODUCTION

Ibuprofen is commonly used as an over-the-counter (OTC) antipyretic and analgesic. As the frequency of its use has increased, there has been a corresponding increase in reports of associated adverse events (AEs). However, these events have not been systematically reported in the literature. Meanwhile, the importance of effective pharmacovigilance in evaluating the benefits and risks of drugs is being recognized.

METHODS

The data was obtained indirectly from FAERS using the OpenVigil 2 database, lexically mapped using software such as MySQL, Microsoft Excel, and the R language, and then subjected to four more rigorous algorithms to detect risk signals associated with ibuprofen AEs.

RESULTS

By analyzing data from the past 18 years, 878 ibuprofen-related AEs were identified as primary AEs. Notably, unexpected reproductive system and breast diseases, etc., which were unexpected, were observed as important system organ classes (SOCs) associated with ibuprofen. Among the 651 preferred terms (PTs) that simultaneously satisfy the four arithmetic methods, renal tubular acidosis and lip oedema are proposed as new signals for ibuprofen AEs.

CONCLUSION

This study explores the important and valuable potential AEs and ADRs of ibuprofen at the SOC and PT levels, respectively. To provide a reference on decision-making for ibuprofen to promote rational clinical dosing.

Evaluation of Safety, Tolerability and Pharmacokinetic Characteristics of SA001 and Its Active Metabolite Rebamipide after Single and Multiple Oral Administration

Dry eye disease (DED) is one of the most common eye diseases caused by multiple factors. Rebamipide, which is currently used to treat peptic ulcer disease, was shown to enhance secretory function and modulate inflammation in animal disease models. Considering the pathophysiology of DED, SA001 was developed expecting enhanced systemic exposure of rebamipide. Clinical trials to evaluate the safety, tolerability and pharmacokinetic (PK) characteristics of SA001 and its active metabolite rebamipide were conducted. After oral administration of SA001, blood and urine samples were collected for PK analysis of SA001 and rebamipide. PK parameters were compared between SA001 and conventional rebamipide (Bamedin^®) and also between fasted and fed. Safety and tolerability were evaluated throughout the study based on adverse events (AEs), physical examinations, vital signs, 12-lead electrocardiography and clinical laboratory tests. SA001 was rapidly absorbed and quickly converted to rebamipide. The systemic exposure of rebamipide was dose-proportional after single and multiple doses. The plasma concentration of rebamipide after administration of SA001 was higher with a dose adjusted AUC_last and C_max 2.20 and 5.45 times higher in the 240 mg dose group and 4.73 and 11.94 times higher in the 600 mg dose group compared to conventional rebamipide. The favorable PK and tolerability profiles support further clinical development.

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.

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.

Mucoprotective drugs can prevent and treat nonsteroidal anti-inflammatory drug-induced small bowel enteropathy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Small bowel enteropathy (SBE) is a complication of nonsteroidal anti-inflammatory drug (NSAID) therapy occurring in 71% of NSAID users. We aimed to analyse the efficacy and safety of medications to prevent and treat NSAID-induced SBE in randomized controlled trials (RCTs).

METHODS

This review was registered on PROSPERO (CRD42021223371). We systematically searched four databases until 20 October for comparing mucoprotective (MP), antibiotic and probiotic treatments to placebo, proton-pump inhibitors (PPIs) or histamine-2 (H2) receptor antagonists in NSAID-associated small intestinal injuries. The main outcomes were mucosal integrity, mucosal breaks after treatment, mucosal injury improvement and complete healing of mucosal breaks. Meta-analytical calculations for weighted mean differences (WMDs) and odds ratios (ORs) were performed with the random-effects model and interpreted with 95% confidence intervals (CIs).

RESULTS

A total of 18 RCTs were included in the quantitative synthesis. MP medications administered preventively reduced the number of mucosal erosions (WMD = -1.24, CI: -2.15 to -0.34) and lead to a significantly lower chance of developing mucosal breaks after treatment (OR = 0.38, CI: 0.16-0.93). MP therapy was associated with a higher rate of complete healing of mucosal breaks (OR = 5.39, CI: 2.79-10.42). In the qualitative synthesis, there were tendencies for a lower increase in the mean number of mucosal breaks and reddened lesions with prophylactic and a higher decrease in mucosal breaks with therapeutic MP drug administration.

CONCLUSION

MP treatment administered with NSAIDs can prevent and reduce small intestinal mucosal lesions.

Asymptomatic small intestinal ulcerative lesions: Obesity and Helicobacter pylori are likely to be risk factors

It is often difficult to explain why ulcerative lesions are found in the small intestine because there are no obvious aggressors such as gastric acid. In particular, the treatment of small intestinal ulcerative lesions in asymptomatic patients with no symptoms, normal physical examinations, and normal blood test findings is not well documented. According to a summary of capsule endoscopy studies in healthy subjects, approximately 10% of subjects have small intestinal mucosal breaks. The number of mucosal breaks in these instances is approximately 1-3. We examined small intestinal mucosal breaks in healthy subjects recruited from our past two studies. Mucosal breaks were observed in approximately 10% of subjects, and the average number was 0.24 ± 1.21. The number of mucosal breaks in the small intestine was correlated with body mass index and was significantly higher in Helicobacter pylori-infected subjects and higher in males. These results indicate that 1-2 small ulcerative lesions, such as erosions in the small intestine, can be considered to be in the normal range, and close examination is not required. It is assumed that a follow-up medical examination is required for such asymptomatic persons. The presence of many small ulcerative lesions or an unequivocal ulcer indicates an abnormality for which close examination is desired. However, in many cases, it is sufficient to scrutinize after detecting anemia, but it is difficult to make a judgment due to insufficient reports, and future studies are required.

Potential Strategies in the Prevention of Nonsteroidal Anti-inflammatory Drugs-Associated Adverse Effects in the Lower Gastrointestinal Tract

With the increasing use of nonsteroidal anti-inflammatory drugs (NSAIDs), the incidence of lower gastrointestinal (GI) complications is expected to increase. However, unlike upper GI complications, the burden, pathogenesis, prevention and treatment of NSAID-associated lower GI complications remain unclear. To date, no cost-effective and safe protective agent has been developed that can completely prevent or treat NSAID-related lower GI injuries. Selective COX-2 inhibitors, misoprostol, intestinal microbiota modulation, and some mucoprotective agents have been reported to show protective effects on NSAID-induced lower GI injuries. This review aims to provide an overview of the current evidence on the prevention of NSAID-related lower GI injuries.

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.

Protective effect and mechanism of rebamipide on NSAIDs associated small bowel injury

PURPOSE

To investigate the protective effect and mechanism of rebamipide on NSAIDs associated intestinal injury.

METHODS

Intestinal injury was induced in Sprague Dawley rats by intragastric administration of diclofenac with rebamipide intervention, and LPS and TAK-242 were given intraperitoneally respectively. The expression of TLR4/NF-κB and the related proteins in the intestinal mucosa were detected. 55 patients taking NSAIDs and diagnosed as NSAIDs associated small intestinal injury were recruited as NSAIDs group. Another 55 patients without NSAIDs and no obvious abnormality in the small bowel served as the control group.

RESULTS

The macroscopic and histological scores of the small intestinal mucosa in the rebamipide pretreatment group were significantly lower compared to the diclofenac group (p < 0.01). The expressions of Tollip, ZO-1 and Claudin-1 in the diclofenac group were down-regulated compared with that in the control group, while they increased significantly in the rebamipide pretreatment group (p < 0.01). The expressions of TLR4/NF-κBp65, IL-1β, IL-6, IL-8, and TNF-α significantly increased in the model group while they were down-regulated in the rebamipide pretreatment group (p < 0.05). Administration of LPS 1 h after diclofenac aggravated small intestinal damage, and increased expression of IL-1β, IL-6, IL-8 and TNF-α. Administration of rebamipide did not effectively reverse intestinal injury induced by diclofenac and LPS. In contrast, pretreatment with TAK-242 significantly inhibited damage and prevented the increased expression of the cytokines. The expression of TLR4 and NF-κBp65 in the patients with NSAIDs associated intestinal injury was significantly higher than that in the control group (p < 0.01), while the expression of Tollip was decreased (p < 0.01).

CONCLUSION

Rebamipide effectively alleviated intestinal mucosa injury by probably suppressing the TLR4/NF-κB signaling pathway and the decreasing of ZO-1 and Claudin-1 induced by diclofenac.

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.

Herb-drug interaction in the protective effect of Alpinia officinarum against gastric injury induced by indomethacin based on pharmacokinetic, tissue distribution and excretion studies in rats

Alpinia officinarum Hance of the Chinese traditional herb for the treatment of emesis, abdominal pain and diarrhea has been used to counteract gastric disease induced by indomethacin in rats without obvious side effects. However, the role of herb-drug interaction between indomethacin and A. officinarum based on pharmacokinetic, tissue distribution and excretion still remains unknown. In this study, an ultra-fast liquid-tandem mass spectrometry (UFLC-MS/MS) method was developed for simultaneous determination of indomethacin and its three metabolites, O-desmethylindomethacin (ODI), deschlorobenzoylindomethacin (NDI) and indomethacin acyl-β-D-glucuronide (IDAβG) by oral administration of indomethacin solution with and without the ethanolic extract of A. officinarum and applied to comparative pharmacokinetic, tissue distribution and excretion studies. Our results clarified that oral administration of A. officinarum produced significant alterations in the pharmacokinetic parameters of indomethacin. And the pharmacokinetic interaction between indomethacin and A. officinarum reduced the systemic exposure of indomethacin and increased its elimination. Tissue distribution results demonstrated that co-administration of A. Officinarum could not reduce the accumulation of indomethacin in the target tissue of the stomach, but could accelerate the excretions of indomethacin and its three metabolites including ODI, NDI and IDAβG in the bile and feces of rats in the excretion study. Therefore, A. Officinarum might have a gastrointestinal protective effect through the interaction role with indomethacin based on the pharmacokinetics and excretion in rats.

[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.

Drug-Induced Small Bowel Injury: a Challenging and Often Forgotten Clinical Condition

PURPOSE OF REVIEW

Most drugs are given by the oral route. Oral intake allows direct contact between the drug and the entire GI tract mucosa, exposing it to potential topical damage until absorption. Medication-induced GI symptoms and lesions are therefore commonly encountered in clinical practice. This review will examine the most common drugs or classes of drugs affecting small bowel function and/or structure.

RECENT FINDINGS

Since non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used medicines, NSAID enteropathy is highly prevalent and brings about considerable morbidity. Antimicrobials and proton-pump inhibitors profoundly modify intestinal microbiota, affecting gut sensory and motor functions, while other drugs (like iron and gold derivatives) impair intestinal permeability. Olmesartan (and likely ACE inhibitors) induce villous atrophy and consequent malabsorption. Mycophenolate mofetil, cancer chemotherapeutic agents, and immune checkpoint inhibitors cause intestinal inflammation, abdominal pain, and diarrhea. Potassium chloride supplements may induce small bowel ulceration, stenosis, and perforation while the cotraceptive pill and anticoagulants are associated with intestinal ischemia and spontaneous intramural hematoma, respectively. In clinical practice, a deep knowledge of clinical pharmacology and toxicology and a high degree of suspicion of drug-related adverse events are mandatory. Only then, the practicing physician will be able to diagnose medication-induced small bowel lesions correctly and will implement the best strategies to treat them.

Effectiveness of acid suppressants and other mucoprotective agents in reducing the risk of occult gastrointestinal bleeding in nonsteroidal anti-inflammatory drug users

Acid suppressants such as histamine-2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) are effective in preventing gastrointestinal (GI) bleeding in nonsteroidal anti-inflammatory drugs (NSAIDs) users. Despite widespread acid suppressant use, there remain concerns about several potential risks of long-term use. Therefore, we investigated whether gastroprotective agents (GPAs) other than acid suppression therapy are effective in preventing NSAID-related GI injury. To this end, we studied 9,133 patients with osteoarthritis or rheumatoid arthritis who used NSAIDs for ≥1 month. A decrease of 2 g/dL or more in the hemoglobin level was considered a GI injury indicator. The GPAs included acid suppressants and other mucoprotective agents. Acid suppressants included PPIs and H2RAs. Other mucoprotective agents included misoprostol, rebamipide, and eupatilin. During a median follow-up period of 27 (range, 4.3-51.3) weeks, occult GI bleeding occurred in 1,191 (13%) patients. A comparison of patients who used GPAs concomitantly with that of nonusers in a multivariable analysis revealed the hazard ratios (HRs; 95% confidence intervals [CIs]) for occult GI bleeding were 0.30 (0.20-0.44), 0.35 (0.29-0.43), 0.47 (0.23-0.95), 0.43 (0.35-0.51), and 0.98 (0.86-1.12) for PPIs, H2RAs, misoprostol, rebamipide, and eupatilin, respectively. Compared to PPI co-treatment, H2RA, misoprostol, rebamipide, and eupatilin co-treatments were associated with occult GI bleeding HRs (95% CIs) of 1.19 (0.79-1.79), 1.58 (0.72-3.46), 1.44 (0.96-2.16), and 3.25 (2.21-4.77), respectively. Our findings suggest that mucoprotective agents, such as rebamipide and misoprostol, as well as acid suppressants, are effective in reducing the risk for GI injury in NSAID users.

Bactericidal/Permeability-Increasing Fold-Containing Family B Member 4 May Be Associated with NSAID-Induced Enteropathy

BACKGROUND

There is considerable individual variability in nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy.

AIM

To identify the SNP that is most significantly involved with NSAID-induced enteropathy.

METHODS

One hundred fifty human subjects who were known to have a certain degree of loxoprofen- or celecoxib-induced small-intestinal damage from a previous study were enrolled. The subjects were divided into groups based on treatments and also on the increased number of small intestinal mucosal breaks. The candidate SNP was selected by an initial analysis of GWAS among the groups in various combinations. After the initial analysis, the gene including the specified SNP was analyzed in detail using GWAS and genotype imputation.

RESULTS

After analysis, 70 subjects receiving the loxoprofen treatment and 69 subjects receiving celecoxib treatment were determined to be eligible for the analysis. The minimum p value in GWAS was detected in the analysis of 16 cases with an increase of five or more mucosal breaks and 123 controls with zero to four mucosal breaks. In the GWAS, five SNPs in the bactericidal/permeability-increasing fold-containing family B member 4 (BPIFB4) gene showed the lowest p value (p = 2.69 × 10^-7 with an odds ratio of 40.9). Of the five SNPs, four were nonsynonymous SNPs (rs2070325: V268I, rs2889732: T320N, rs11699009: F527L, rs11696307: T533I, and rs11696310: intronic). Furthermore, 23 SNPs in BPIFB4 detected by genotype imputation based on the GWAS data also showed suggestive associations (p < 1 × 10^-6).

CONCLUSION

The results indicate that SNPs in BPIFB4 were associated with NSAID-induced small intestinal mucosal injury (UMIN: 000007936).

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.

Associations between drugs and small-bowel mucosal bleeding: Multicenter capsule-endoscopy study

BACKGROUND AND AIM

Although several drugs may induce small-bowel mucosal injuries, it is unclear whether these injuries contribute to overt small-bowel bleeding. This study was designed to evaluate the associations between drug use and small-bowel mucosal injury and between these mucosal injuries and overt bleeding in a disease-relevant population.

METHODS

We retrospectively studied patients with suspected small-bowel diseases who underwent capsule endoscopy between 2010 and 2013. Drug exposure, Charlson Comorbidity Index, smoking, and alcohol consumption were assessed before capsule endoscopy. Adjusted odds ratios (AOR) and confidence intervals (CI) were estimated for small-bowel mucosal injury and small-bowel overt bleeding.

RESULTS

In total, 850 patients were analyzed during the study period. Median age was 64 years, and 544 patients (64.0%) were men. Among the patients with small-bowel mucosal injury (n = 60) and without mucosal injury (n = 705), use of non-steroidal anti-inflammatory drugs (NSAIDs) (AOR 1.8, 95% CI 1.01-3.31) was significantly associated with an increased risk of small-bowel mucosal injury compared with non-use. Patients with small-bowel mucosal injury with overt bleeding (n = 85) and without overt bleeding (n = 60) were compared, and no significant difference between the groups in the usage rates for NSAIDs, thienopyridine, other antiplatelets, anticoagulants, acetaminophen, tramadol hydrochloride, or steroids was revealed, even after adjusting for confounders.

CONCLUSION

Although the use of NSAIDs was significantly associated with an increased risk of small-bowel mucosal injury, no significant associations were observed between the use of such drugs and small-bowel overt bleeding.

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.

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.

Yogurt Containing Lactobacillus gasseri Mitigates Aspirin-Induced Small Bowel Injuries: A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Although there is evidence about the beneficial effects of probiotics, their effects on aspirin-induced small bowel injuries have not been well examined. We evaluated the effects of the probiotic Lactobacillus gasseri OLL2716 (LG) on aspirin-induced small intestinal lesions, such as ulcers, erosions, reddened lesions, and bleeding.

SUMMARY

This study enrolled 64 patients who received aspirin for more than 1 month and provided written informed consent to be part of the study. The patients received 112 ml of yogurt containing LG or placebo twice daily for 6 weeks. Small bowel injuries were evaluated by capsule endoscopy before and after consuming the yogurt. The effect of LG on patient symptoms was also assessed using the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease (FSSG) and Gastrointestinal Symptom Rating Scale (GSRS) questionnaires before and after 6 weeks of treatment. There was no significant difference in any baseline characteristics and the number of small bowel mucosal breaks between the 2 groups. In contrast with the placebo group, the LG group had significantly fewer small bowel mucosal breaks and reddened lesions after 6 weeks (p < 0.01). The FSSG and GSRS scores were also significantly improved in the LG group but not in the placebo group. Key Messages: This double-blind, placebo-controlled study found that LG may be useful in reducing aspirin-induced small bowel injuries and in mitigating gastrointestinal symptoms.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Celecoxib Monotherapy Maintained Small Intestinal Mucosa Better Compared With Loxoprofen Plus Lansoprazole Treatment: A Double-blind, Randomized, Controlled Trial

GOALS

The aim of this study was to compare celecoxib with loxoprofen for protection of small intestine.

BACKGROUND

RCT studies report that COX-2 selective inhibitor celecoxib induces fewer small intestinal injuries than nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). Loxoprofen is a prodrug nonselective NSAID developed to protect upper gastrointestinal tract.

STUDY

A total of 150 healthy volunteers (40 to 70 y) were enrolled. After medical checkup including laboratory data, subjects were randomly assigned to celecoxib (200 mg daily) or loxoprofen (180 mg daily) plus lansoprazole (15 mg daily). All drugs were prepared using inactive capsules. After randomization, all subjects were first examined by baseline capsule endoscopy (CE). After 14 days, subjects underwent posttreatment CE. We compared baseline and posttreatment CE findings of the 2 groups. All CE data were evaluated blindly by 3 reviewers. Pretreatment and posttreatment laboratory variables were also compared.

RESULTS

A total of 74 subjects (49±6 y, F/M: 36/38) were enrolled in celecoxib group and 76 subjects (49±7 y, F/M: 39/37)in loxoprofen group. Five in celecoxib group and 4 in loxoprofen group were excluded from CE analysis mainly due to incomplete CE. The percentage of subjects with at least 1 posttreatment mucosal break was lower in celecoxib group (10%) than in loxoprofen group (49%) (P<0.0001). A total of 0.3±1.0 posttreatment small intestinal mucosal breaks were detected in the celecoxib group, and 6.8±21.5 in the loxoprofen group (P<0.0001). Posttreatment hemoglobin concentration in loxoprofen group (5.1% reduction) was lower compared with celecoxib group (2.1% reduction) (P=0.006).

CONCLUSIONS

In terms of protection of small intestine from NSAIDs toxicity, celecoxib monotherapy was superior to loxoprofen+lansoprazole combination therapy (UMIN: 000007936).

[Small bowel injuries due to nonsteroidal anti-inflammatory drugs and antiplatelet therapy. Approaches to prevention and treatment]

Nonsteroidal anti-inflammatory drug (NSAID)-induced small bowel injuries (NSAID enteropathies) become clinically important. Videocapsule endoscopy shows that the small bowel is involved in NSAID-related gastrointestinal tract (GIT) injury in almost two-thirds of all cases. Due to a large number of patients who receive NSAIDs, combined antiplatelet therapy, or long use anticoagulants, GIT injury prevention becomes an actual problem. Treatment for NSAID enteropathy is different from that for NSAID gastropathy. In NSAID enteropathy, it is advisable to use drugs that are able to increase the production of prostaglandins and mucus, to restore intestinal epithelial permeability, and to exert anti-inflammatory and antioxidant effects. Rebamipide that produces many pleiotropic effects and also has cytoprotective properties may become the drug of choice for treating patients with NSAID enteropathy. In addition, rebamipide has no effects on various cytochrome P-450 enzyme systems, by reducing the risk of drug interactions.

Risk factors for small bowel bleeding in chronic nonsteroidal anti-inflammatory drug users

OBJECTIVE

The incidence of nonsteroidal anti-inflammatory drugs (NSAIDs)-induced enteropathy is currently increasing. However, the predictors of small bowel bleeding (SBB) associated with NSAIDs are unknown. This study aimed to assess the risk factors of SBB in chronic NSAIDs users.

METHODS

We retrospectively compared the medical records of 147 patients receiving NSAIDs in a tertiary-care setting (31 with SBB and 116 without previous bleeding events) and analyzed the predictors of SBB.

RESULTS

In total, 31 patients underwent video capsule endoscopy to detect SBB, 74.2% of whom showed the evidence of SBB. Non-invasive treatment was performed in 90.3% of the patients. Multivariate logistic regression analysis revealed that the presence of coronary artery disease [adjusted odds ratio (aOR) 12.43, 95% confidence interval (CI) 1.19-130.34, P = 0.04], use of thienopyridine (aOR 16.93, 95% CI 3.78-75.72, P < 0.001) and prior use of rebamipide (aOR 0.31, 95% CI 0.12-0.82, P = 0.02) were independently associated with SBB in NSAIDs users.

CONCLUSIONS

Coronary artery disease and co-use of thienopyridine were associated with SBB in NSAIDs users. The patients with coronary artery disease co-using thienopyridine need to be monitored for the occurrence of SBB when they were prescribed with NSAIDs.

Protective effect of rabamipide on non-steroid anti-inflammatory drug induced enteropathy in rats

AIM: To investigate the effect of rabamipide on non-steroid anti-inflammatory drug (NSAID) induced enteropathy in rats and the possible mechanism.

METHODS: Thirty male Sprague-Dawley rats were randomized into three groups: a control group, a diclofenac induced injury group, and a rabamipide pretreatment group. Intestinal injury was induced in rats of the diclofenac induced injury group and rabamipide pretreatment group by intragastric administration of diclofenac (7.5 mg/kg) once per day for continuous 4 d. The rabamipide pretreatment group was pretreated with rabamipide 100 mg/(kg•d) orally once daily 1 h before the administration of diclofenac. The control group received 0.9% NaCl by gavage during the same period. All the rats were sacrificed on the 4^th day. Small intestinal injuries were assessed for histopathological damage and macroscopic injury and recorded as corresponding scores. Immunohistochemistry and Western blot were used to detect the distribution and expression of intestinal epithelial tight junction protein occludin. The expression of ERK, p38, phosphorylated ERK (p-ERK) and phosphorylated p38 (p-p38) was determined by Western blot.

RESULTS: Compared with the control group, histopathological and macroscopic scores of intestinal damage were significantly increased in the diclofenac induced injury group (P < 0.05). Intestinal damage scores in the rabamipide pretreatment group were significantly decreased compared with those in the diclofenac induced injury group (P < 0.05). Compared with the control group, expression of occludin in the diclofenac induced injury group was decreased significantly (P < 0.05), while that in the rabamipide pretreatment group increased significantly compared with the diclofenac induced injury group (P < 0.05). Significant activation of ERK and p38 was seen in the diclofenac induced injury group compared with the control group (P < 0.05), and pretreatment with rabamipide significantly inhibited the activation of ERK and p38 compared with the diclofenac induced injury group (P < 0.05).

CONCLUSION: Rabamipide has a protective effect on NSAID induced enteropathy in rats, probably by increasing the expression of occludin protein and inhibiting the activation of ERK as well as p38 signaling pathways.

Rebamipide Promotes the Regeneration of Aspirin-Induced Small-Intestine Mucosal Injury through Accumulation of β-Catenin

BACKGROUND

The effect of rebamipide on repairing intestinal mucosal damage induced by nonsteroidal anti-inflammatory drugs and its mechanism remain unclear. In this study, we sought to explore the mechanism whereby rebamipide could promote the regeneration of aspirin-induced intestinal mucosal damage.

METHODS

BALB/c mice were administered aspirin (200 mg/kg/d) for 5 days to induce acute small intestinal injury (SII). Subsequently, SII mice were treated with rebamipide (320 mg/kg/d) for 5 days. The structure of intestinal barrier was observed with transmission electron microscope, and Zo-1 and occludin expressions were detected. The proliferative index was indicated by the percentage of proliferating cell nuclear antigen positive cells. The prostaglandin E2 (PGE2) levels in the small intestine tissues were measured by an enzyme immunoassay. The mRNA and protein expression levels of cyclooxygenase (COX) and β-catenin signal were detected in the small intestine using quantitative PCR and Western blot, respectively.

RESULTS

COX expression was significantly down-regulated in aspirin induced SII (P < 0.05). In SII mice treated with rebamipide, histopathological findings of aspirin-induced intestinal inflammation were significantly milder and tight junctions between intestinal epithelial cells were improved significantly. The proliferative index increased after rebamipide treatment when compared with that in the control mice. The expressions of COX-2, β-catenin, and c-myc and the PGE2 concentrations in small intestinal tissues were significantly increased in mice with rebamipide treatments (P < 0.05).

CONCLUSION

Rebamipide administration in aspirin-induced SII mice could improve the intestinal barrier structure and promote the regeneration of small intestinal epithelial injury through up-regulating COX-2 expression and the accumulation of β-catenin.

Effect of long-term proton pump inhibitor therapy and healing effect of irsogladine on nonsteroidal anti-inflammatory drug-induced small-intestinal lesions in healthy volunteers

This study assessed time-course changes of the small intestinal lesions during long-term treatment with diclofenac sodium plus omeprazole and the effects of irsogladine on such lesions. Thirty two healthy volunteers were treated with diclofenac sodium (75 mg/day) plus omeprazole (10 mg/day) for 6 weeks, with irsogladine (4 mg/day) added from weeks 6 to 10 (Group A) or with diclofenac sodium plus irsogladine for 6 weeks (Group B). Five volunteers received diclofenac sodium plus omeprazole for 10 weeks (Group C). Subjects underwent capsule endoscopy at each time. In Group A, the number of lesions remarkably increased at week 2, but the worse was not found at week 6 compared with week 2, whereas no exacerbation of lesions was observed in Group B. Additional treatment with irsogladine from weeks 6 to 10 in Group A significantly decreased the number of lesions at weeks 10 compared with Group C. In Group C, no significant change in lesions was observed since weeks 2. In conclusions, a PPI did not prevent the occurrence of small intestinal damage. However such lesions were not aggravated since weeks 2. These suggested mucosal adaptation may occur in the small intestine. Irsogladine was effective in both preventing and healing such lesions.

Indomethacin suppresses LAMP-2 expression and induces lipophagy and lipoapoptosis in rat enterocytes via the ER stress pathway

BACKGROUND

Indomethacin enhances small intestinal epithelial cell apoptosis, which may account for mucosal ulceration. However, the involvement of autophagy in indomethacin-induced enterocyte damage is unreported.

METHODS

Using light microscopy and electron microscopy techniques, Western blot analysis, and pharmacological inhibition of autophagy, we investigated the autophagic response of cultured rat enterocytes to indomethacin treatment (200 µM) at various time points. Furthermore, autophagy was examined in enterocytes of rats given indomethacin by gavage (10 mg/kg).

RESULTS

Our data indicate that indomethacin induced accumulation of cytoplasmic lipid droplets (LDs) in cultured enterocytes, which was associated with time-dependent autophagic responses. Initially (0-6 h), mediated by endoplasmic reticulum stress and suppression of mammalian target of rapamycin, a predominant cytoprotective lipophagy was activated in indomethacin-treated enterocytes, as evidenced by induction and colocalization of LC3-II with LDs, excessive formation of autophagosomes sequestering LDs (autolipophagosomes; ALPs), and decreased viability of enterocytes on blocking autophagy with 3-methyladenine. On prolonged exposure to indomethacin (6-24 h), there was a decrease of LAMP-2 expression in enterocytes coupled with accumulation of ALPs and LDs with fewer autolysosomes in addition to an elevation of lipoapoptosis. These time-dependent autophagic and apoptotic responses to indomethacin treatment were detected in enterocytes of indomethacin-treated rats, confirming in vitro results.

CONCLUSIONS

The findings of this study describe a novel mechanism of enterocyte damage by indomethacin mediated by endoplasmic reticulum stress, accumulation of LDs, and subsequent activation of the early phase of cytoprotective lipophagy. This is followed by a late phase characterized by reduced expression of lysosomal autophagic proteins, accumulation of ALPs, and enhanced lipoapoptosis.

Environmental and NSAID-enteropathy: dysbiosis as a common factor

At first sight, environmental enteropathy and NSAID enteropathy may appear to have little in common. One occurs almost exclusively in poor countries and the other primarily in rich countries. One is the consequence of unhygienic living conditions, while the other is a consequence of use of a drug for relief of pain and inflammation. However, there may be a common pathogenic link between these two conditions, namely a significant alteration in the microbiome (dysbiosis), and this raises the possibility of common approaches to treatment. Correction of the dysbiosis that is central to the intestinal tissue injury and dysfunction observed in environmental and nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathies is a logical approach to bringing about restoration of intestinal function. For both conditions, removal of the trigger for dysbiosis is the simplest approach, but is not always feasible. Correcting the underlying dysbiosis through the use of probiotics or prebiotics may be a viable option.

Omeprazole increased small intestinal mucosal injury in two of six disease-free cases evaluated by capsule endoscopy

Recently, a report showed that proton-pump inhibitors (PPI) exacerbate non-steroidal anti-inflammatory drug-induced small intestinal injury in the rat. In the present report of two human cases, small intestinal injuries were probably induced and/or exacerbated after PPI treatment. Case 1 was a 30-year-old healthy man in whom no small intestinal mucosal break was detected at baseline capsule endoscopy. After 2 weeks of omeprazole given 20 mg once daily, he was found to have two small intestinal mucosal breaks. Case 2 was a 40-year-old healthy man in whom six small intestinal mucosal breaks were detected at baseline capsule endoscopy. After 2 weeks of omeprazole given 20 mg once daily, 12 small intestinal mucosal breaks were detected. Follow-up capsule endoscopy carried out 3 weeks after stopping omeprazole in case 2 showed seven small intestinal mucosal breaks were detected, showing restitution of the small intestinalmucosal injury. These two cases were obtained from a pilot study evaluating the effect of single administration of PPI on small intestinal mucosa in humans. In the pilot study, six healthy male volunteers were given omeprazole 20 mg for a period of 2 weeks. Small intestinal injury was evaluated before and after PPI treatment using capsule endoscopy. In four subjects other than the two above-mentioned cases, no small intestinal mucosal breaks were found at both baseline and post-treatment capsule endoscopy. Considering the two cases with increased or newly detected small intestinal mucosal breaks, omeprazole may exacerbate/induce small intestinal injury.

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.

A randomized, double-blinded, placebo-controlled, multicenter trial, healing effect of rebamipide in patients with low-dose aspirin and/or non-steroidal anti-inflammatory drug induced small bowel injury

BACKGROUND

It is not clear what kind of drug is appropriate to heal NSAID-induced enteropathy. Several reports showed the preventive effect of prostaglandin analogue or inducer using healthy subjects who took NSAIDs. However there was no report for healing effect and for patients. The aim of this study was to evaluate the healing effect of rebamipide in patients with NSAIDs-induced enteropathy. In addition, we evaluated for nutritional parameter.

METHODS

This study was conducted as a randomized, double-blinded, placebo-controlled, multicenter trial. Study protocol was approved by each hospital's ethical committees. Patients with LDA and/or NSAID more than 3 months were enrolled. Patients with enteropathy were divided into the placebo and the rebamipide groups. Rebamipide 100 mg three times daily was administered during 4 weeks. Capsule endoscopies were performed at 0 and 4 week. The number of small intestinal ulcer and erosion were evaluated. Total protein was analyzed as nutritional parameter.

RESULTS

Sixty one participants were completed this study. Change in number of small intestinal erosion in the rebamipide group was -2.5 ± 3.4, and 2.1 ± 3.9 in the placebo group (P < 0.0001). Change in number of small intestinal ulcer in the rebamipide group was -0.5 ± 1.6, and 0.1 ± 0.7 in the placebo group (P = 0.024). Change in serum total protein levels in the rebamipide group was 0.06 ± 0.36, and -0.27 ± 0.34 in the placebo group (P = 0.0005).

CONCLUSIONS

Rebamipide has not only the healing effect for NSAIDs-induced enteropathy compared with placebo, but the improvement of nutritional condition. These results showed a tentative therapeutical strategy for chronic NSAIDs users.

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.

NSAID enteropathy: could probiotics prevent it?

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used drugs in the world; nevertheless, about 50-70% of patients on long-term NSAIDs develop small intestine injury, namely NSAID enteropathy, sometimes with serious outcomes. No medications with proven efficacy are yet available to prevent NSAID enteropathy. A series of therapeutic strategies targeting the different mechanisms involved in small bowel injury have been investigated, but without definitive results. Intestinal bacteria and their degradation products are essential for the development of NSAID-induced small bowel lesions, because "germ-free" animals were found to be resistant to indomethacin injuries. Therefore, it has been suggested that modulating the intestinal flora, for example by using probiotics, could protect against NSAID enteropathy. In this work, we reviewed the main therapeutic strategies for NSAID enteropathy, in particular analyzing the available studies relating to the eventual protective role of probiotics. We found that results are not all concordant; nevertheless, the more recent studies provide better understanding about pathogenetic mechanisms involved in small intestinal injury and the role of probiotics, and show encouraging results. Larger and well-designed studies should be performed to evaluate the actual role of probiotics in NSAID enteropathy, the eventual differences among probiotic strains, dose-responses, and optimal duration of therapy.

Preventive effect of irsogladine or omeprazole on non-steroidal anti-inflammatory drug-induced esophagitis, peptic ulcers, and small intestinal lesions in humans, a prospective randomized controlled study

Background

Proton-pump inhibitors such as omeprazole are a standard treatment to prevent non-steroidal anti-inflammatory drug-induced upper gastrointestinal mucosal injuries. However, it is unclear which drugs may protect against all NSAID-induced digestive-tract injuries. Here, we compare the efficacy of the gastromucoprotective drug irsogladine with omeprazole in preventing NSAID-induced esophagitis, peptic ulcers, and small-intestinal mucosal injury in healthy subjects.

Methods

Thirty-two healthy volunteers were assigned to an irsogladine group (Group I; n = 16) receiving diclofenac sodium 75 mg and irsogladine 4 mg daily for 14 days, or an omeprazole group (Group O; n = 16) receiving diclofenac sodium 75 mg and omeprazole 10 mg daily for 14 days. Esophagitis and peptic ulcers were evaluated by esophagogastroduodenoscopy and small-intestinal injuries by capsule endoscopy, fecal calprotectin, and fecal occult blood before and after treatment.

Results

There was no significant difference between Group I and Group O with respect to the change in lesion score in the esophagus, stomach, and duodenum before and after treatment.NSAID treatment significantly increased the number of small intestinal mucosal breaks per subject by capsule endoscopic evaluation, from a basal level of 0.1 ± 0.3 up to 1.9 ± 2.0 lesions in Group O (p = 0.0002). In contrast, there were no significant changes in the mean number of mucosal breaks before and after co-treatment in Group I (0.3 ± 0.8 to 0.5 ± 0.7, p = 0.62), and the between-group difference was significant (p = 0.0040). Fecal calprotectin concentration, when the concentration before treatment was defined as 1, was significantly increased both in Group O (from 1.0 ± 0.0 to 18.1 ± 37.1, p = 0.0002) and Group I (from 1.0 ± 0.0 to 6.0 ± 11.1, p = 0.0280); the degree of increase in Group O was significantly higher compared with that in Group I (p<0.05). In addition, fecal occult blood levels increased significantly in Group O (p = 0.0018), but there was no change in Group I (p = 1.0), and the between-group difference was significant (p = 0.0031).

Conclusion

Irsogladine protected against NSAID-induced mucosal injuries throughout the gastrointestinal tract, from esophagus to small intestine, significantly better than omeprazole.

Trial registration

This study was registered in the UMIN Clinical Trials Registry (Registry ID number; UMIN000008114)

Evaluation of selective cyclooxygenase-2 inhibitor-induced small bowel injury: randomized cross-over study compared with loxoprofen in healthy subjects

AIM

Non-steroidal anti-inflammatory drugs have the potential to injure the mucosa of the upper digestive tract and small bowel, whereas celecoxib (a selective cyclooxygenase-2 inhibitor) has less influence on the entire digestive tract mucosa. The present study was conducted to compare the extents of small bowel mucosal injury induced by celecoxib and loxoprofen (the most frequently used non-steroidal anti-inflammatory drugs in Japan).

METHODS

Ten healthy adult males were given celecoxib (200 mg/day, Group C) and loxoprofen (180 mg/day, Group L) in a cross-over design for 14 days, and the influence of each drug on small bowel mucosa was evaluated by comparing pre- and post-treatment capsule endoscopy findings. We measured the percentage of patients with small bowel mucosal injury following administration of these drugs as primary endpoint. Additionally, mean number of small bowel mucosal injuries per subject was analyzed as secondary endpoint.

RESULTS

The percentage of subjects experiencing small bowel mucosal injury as primary endpoint was 10% in Group C and 70% in Group L after treatment. This magnitude of the difference of between Group C and Group L was statistically significant (P = 0.031). The number of small bowel mucosal injuries as secondary endpoint differed significantly between the two groups, and the influence of celecoxib on small bowel injury was less than that of loxoprofen.

CONCLUSION

These results indicate that celecoxib has less influence on small bowel mucosa than loxoprofen and can be used safely.

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.

Rebamipide inhibits indomethacin-induced small intestinal injury: possible involvement of intestinal microbiota modulation by upregulation of α-defensin 5

Enterobacteria play important roles in the pathophysiology of small intestinal injuries induced by nonsteroidal anti-inflammatory drugs (NSAIDs). We investigated the effects of rebamipide, a gastrointestinal mucoprotective drug, on indomethacin-induced small intestinal injuries, intestinal microbiota, and expression levels of α-defensin 5, which is a Paneth cell-specific antimicrobial peptide and is important for the regulation of intestinal microbiota. Indomethacin (10mg/kg) was orally administered to mice after oral administration of rebamipide (100 or 300 mg/kg) or vehicle for 1 week, and the small intestinal injuries were assessed. After oral administration of rebamipide, the small intestinal contents were subjected to terminal restriction fragment length polymorphism (T-RFLP) analysis to assess the intestinal microbiota composition. Further, the expression levels of mRNA and protein for α-defensin 5 in the ileal tissue were determined by real-time reverse transcription-polymerase chain reaction and western blotting analysis, respectively. Rebamipide inhibited indomethacin-induced small intestinal injuries and T-RFLP analysis showed that rebamipide increased the percentage of Lactobacillales and decreased the percentage of Bacteroides and Clostridium than that in vehicle-treated controls. The mice that were treated with rebamipide showed an increase in α-defensin 5 mRNA expression and protein levels in the ileal tissue compared to vehicle-treated control mice. Indomethacin reduced expression of α-defensin 5 mRNA in ileal tissue, while rebamipide reversed expression of α-defensin 5 mRNA. In conclusion, our study results suggest that rebamipide inhibits indomethacin-induced small intestinal injuries, possibly by modulating microbiota in the small intestine by upregulation of α-defensin 5.

Rebamipide ameliorates indomethacin-induced small intestinal injury in rats via the inhibition of matrix metalloproteinases activity

BACKGROUND AND AIM

The pathogenesis of non-steroidal anti-inflammatory drugs (NSAIDs)-induced small intestinal lesions remains unclear, although it is considered to be quite different from that of upper gastrointestinal tract ulcers due to the absence of acid and the presence of bacteria and bile in the small intestine. The aim of this study was to characterize specific gene expression profiles of intestinal mucosa in indomethacin-induced small intestinal injury, and to investigate the effects of rebamipide on the expression of these genes.

METHODS

Intestinal injury was induced in male Wistar rats by subcutaneous administration of indomethacin. Total RNA of the intestinal mucosa was extracted 24 h after indomethacin administration, gene expression was investigated using microarray analysis, and the identified genes were confirmed by real-time polymerase chain reaction (PCR). In addition, we investigated whether the treatment with rebamipide altered the expression of these identified genes.

RESULTS

The administration of indomethacin induced small intestine injuries, and these lesions were significantly inhibited by the treatment with rebamipide. Microarray analysis showed that the genes for several matrix metalloproteinases (MMPs) and several chemokine-related genes were significantly upregulated, and metallothionein 1a (MT1a) was downregulated in the intestinal mucosa after administration of indomethacin. The expressions of these genes were reversed by the treatment with rebamipide.

CONCLUSION

These data suggest that MMPs, chemokines, and MT1a may play an important role in the intestinal mucosal injury induced by indomethacin. In particular, the inhibition of MMP genes and chemokine-related genes by rebamipide may be important for the therapeutic effect against NSAIDs-induced small intestinal injury.

Efficacy of rebamipide for low-dose aspirin-related gastrointestinal symptoms

Gastrointestinal symptoms are a problematic issue for patients who take low-dose aspirin for long time. We conducted a pilot study to investigate the efficacy of combination therapy with proton pump inhibitor and rebamipide. This was a prospective, randomized, double-blind, placebo-controlled cross-over study. All the subjects received aspirin 100 mg and omeprazole 20 mg. The subjects were divided into two groups and received either rebamipide 300 mg or placebo, which was prescribed for 4 weeks. The subjects were instructed to record their gastrointestinal symptom rating scale before the study and 1 and 4 weeks after beginning the protocol. These scores of the groups were compared before and after the treatment to evaluate the severity of their symptoms and the number of symptom items present in each group. For the subjects receiving rebamipide, the total prevalence of lower gastrointestinal symptoms was significantly different from the placebo group (p=0.0093) at week 4. No troublesome symptoms were observed in the rebamipide group. Inconclusion, the administration of rebamipide prevented the occurrence of troublesome symptoms, especially lower gastrointestinal symptoms, in patients taking aspirin and omeprazole. Rebamipide is a candidate drug for combination therapy with proton pump inhibitors to prevent low-dose aspirin-induced gastrointestinal symptoms.

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.