Comparison of Prevention of NSAID-Induced Gastrointestinal Complications by Rebamipide and Misoprostol: A Randomized, Multicenter, Controlled Trial-STORM STUDY

Transcriptome Analysis for Cytoprotective Actions of Rebamipide against Indomethacin-Induced Gastric Mucosal Injury in Rats

We have reported that rebamipide, a gastroprotective drug, suppresses indomethacin-induced gastric mucosal injury in humans and rats. However, the mechanisms of the cytoprotective actions of rebamipide have not been fully addressed. In the present study, we determined mRNA expression profile of the gastric mucosa treated with indomethacin in rats, and investigated the cytoprotective effects of rebamipide against indomethacin-induced injury with a high-density oligonucleotide array (Rat Toxicology U34 GeneChip array). Gastric epithelial cells were obtained by laser-assisted microdissection. Data analysis was performed with a GeneChip Operating Software, GeneSpring software 7.0, and Ingenuity Pathway Analysis. Among 1,031 probes, the expression of 160 probes (15.5%) showed at least 2.0-fold up-regulation (158 probes) and down-regulation (2 probes) 2 h after indomethacin administration in comparison with the vehicle-treated rats. The pathway analysis of the up-regulated 123 probes identified the network with a highly significant score, which consisted of known clusters of cell death, cancer, and endocrine system disorders. We succeeded in listing 10 genes that were up-regulated by the treatment with indomethacin and that were down-regulated by rebamipide, including growth arrest and DNA damage-induced 45α. In conclusion, we demonstrated that cell death, especially apoptosis, pathway is involved in the pathogenesis of indomethacin-induced gastric mucosal injury, and that inhibition of apoptosis-related genes is possibly important for the cytoprotective effect of rebamipide against this injury.

Prevention of Indomethacin-Induced Gastric Mucosal Injury in Helicobacter pylori-Negative Healthy Volunteers: A Comparison Study Rebamipide vs Famotidine

The clinical efficacy of gastroprotective drugs or low-dose H(2) receptor antagonists in the prevention of nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy is limited. The aim of the present study was to investigate efficacy of rebamipide and famotidine in Helicobacter pylori (H. pylori)-negative healthy volunteers taking NSAID. This study was a randomized, two way crossover study comparing the preventive effect rebamipide 100 mg, t.i.d. and famotidine 10 mg, b.i.d against indomethacin (25 mg, t.i.d.)-induced gastric mucosal injury in H. pylori-negative healthy volunteers. 12 subjects satisfied criteria and were randomized. Endoscopy was performed at baseline and again after the treatment for 7 days, and symptoms were recorded during the treatment. Tissue levels of lipid peroxides and myeloperoxidase and serum indomethacin concentrations were also measured. Subjective symptoms were developed in 58% (7/12) of the rebamipide group, and in 75% (9/12) of the famotidine group (no significant differences). The incidence of gastric lesions (modified Lanza score 2 or higher) was 17% (2/12) in the rebamipide group and 25% (3/12) in the famotidine group. Peptic ulcers did not occur in both groups. There were no significant differences in tissue levels of lipid peroxide and myeloperoxidase and serum level of indomethacin between two groups after the treatment. In conclusion, these data recommend rebamipide (100 mg, t.i.d.) or famotidine (10 mg, b.i.d.) for the prevention of acute gastric injury induced by NSAID in patients without a particular risk factor.

Identification of dihalogenated proteins in rat intestinal mucosa injured by indomethacin

Previous studies have shown that activated neutrophils and their myeloperoxidase (MPO)-derived products play a crucial role in the pathogenesis of non-steroidal anti-inflammatory drug (NSAID)-related small intestinal injury. The aim of the present study is to identify dihalogenated proteins in the small intestine on indomethacin administration. Intestinal damage was induced by subcutaneous administration of indomethacin (10 mg/kg) in male Wistar rats, and the severity of the injury was evaluated by measuring the area of visible ulcerative lesions. Tissue-associated MPO activity was measured in the intestinal mucosa as an index of neutrophil infiltration. The dihalogenated proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) using novel monoclonal antibodies against dibromotyrosine (DiBrY), and they were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting and a Mascot database search. Single administration of indomethacin elicited increased ulcerative area and MPO activity in the small intestine. 2D-PAGE showed an increased level of DiBrY-modified proteins in the indomethacin-induced injured intestinal mucosa and 6 modified proteins were found. Enolase-1 and albumin were found to be DiBrY modified. These proteins may be responsible for the development of neutrophil-associated intestinal injury induced by indomethacin.

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

BACKGROUND

A study reported that rebamipide was effective at reducing short-term nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy. The purpose of this study was to re-evaluate the effect of the co-administration of rebamipide on small intestinal injuries induced by short-term NSAID treatment.

METHODS

Eighty healthy male volunteers were randomly assigned to two study groups: a control group (N = 40), which received NSAID (diclofenac sodium, 75 mg/day) and omeprazole (20 mg/day) treatment along with a placebo; and a rebamipide group, which received NSAID, omeprazole and rebamipide (300 mg/day). Small intestinal injuries (mucosal breaks plus denuded areas) were evaluated by capsule endoscopy before and after 14 days of treatment.

RESULTS

A total of 38 control subjects and 34 rebamipide subjects completed the treatment and were evaluated by capsule endoscopy. NSAID therapy increased the mean number of mucosal injuries per subject from a basal level of 0.1 ± 0.3 to 16 ± 71 and 4.2 ± 7.8 in the control and rebamipide groups, respectively, but the difference was not significant. The difference in the percentage of subjects with at least one mucosal injury post-treatment was also not significant (control 63%; rebamipide 47%). Limiting our analysis to subjects with mucosal injuries, rebamipide co-treatment had the tendency to reduce the mean number of mucosal injuries per subject from 25 in the control group to 8.9 in the rebamipide group (multiple comparisons test; p = 0.088, Mann-Whitney U test; p = 0.038).

CONCLUSIONS

Rebamipide co-therapy had the potential to reduce the intensity of small intestinal injury induced by 2-week administration of diclofenac.

Small bowel tissue concentration of rebamipide: study of two dosages in healthy subjects

Non-steroidal anti-inflammatory drug (NSAID)-related small intestinal complications exist, since developed new diagnostic modalities, such as balloon and capsule endoscopies. Some experiments have shown rebamipide to protect from NSAID-induced small intestinal complications. The purpose of this study is to investigate whether the effective concentrations of rebamipide (COR) are present in the small intestine after taking an ordinary clinical dose and double dose of this drug. Twelve healthy male subjects were enrolled. After taking 100 or 200 mg of rebamipide, balloon enteroscopy was performed at 1 and 3 h, and biopsy samples were obtained from the jejunum and the stomach. Venous blood samples were taken simultaneously. Samples were analyzed by high-performance liquid chromatography. The mean COR in the jejunum was higher than 100 µM at 1 h and higher than 10 µM at 3 h in both the 100 and 200 mg groups. Mean COR in the stomach was less than 100 µM at 1 h in the 100 mg group; however it was higher than 100 µM in the 200 mg group. In conclusion, the COR level in the jejunum was sufficient to protect for NSAID-induced gastrointestinal complications.

Gastroduodenal mucosal injury in patients taking low-dose aspirin and the role of gastric mucoprotective drugs: possible effect of rebamipide

The present study was conducted to investigate the prevalence of mucosal injury in patients taking low-dose aspirin in Japan and examine the effect of gastric mucoprotective drugs on aspirin-related gastroduodenal toxicity. We selected 530 patients who had taken low-dose aspirin for 1 month or more after undergoing esophagogastroduodenoscopy from 2005 through 2006 at Teikyo University Hospital, Tokyo, Japan. Endoscopic records were retrospectively reviewed to determine the presence of massive bleeding and mucosal injury (ulcer or erosion). The influence of clinical factors, including co-administration of gastroprotective drugs, was also examined. Hemorrhage was observed in 25 patients (3.7%) and mucosal injury (36.2%) in 192 patients. The presence of Helicobacter pylori antibody was a significant risk factor associated with mucosal injury. Patients taking any gastroprotective drug showed a significantly lower rate of mucosal injury than those not taking these drugs. Patients taking rebamipide concomitantly with proton pump inhibitors or histamine 2 receptor antagonists had mucosal injury less frequently than those taking acid suppressants plus other mucoprotective drugs. In conclusion, these results show the possible gastroprotective effects of rebamipide, suggesting that it may be a good choice in aspirin users with gastroduodenal toxicity that is not suppressed by acid suppressants alone.

Rebamipide: a gastrointestinal protective drug with pleiotropic activities

Rebamipide, a gastroprotective drug, was developed in Japan and was proven to be superior to cetraxate, the former most prescribed drug of the same category, in 1989 in the treatment for gastric ulcers. The initially discovered basic mechanisms of action of rebamipide included its action as a prostaglandin inducer and oxygen free-radical scavenger. In the last 5 years, several basic and clinical studies have been performed for functional dyspepsia, chronic gastritis, NSAID-induced gastrointestinal injuries, gastric ulcer following eradication therapy for Helicobacter pylori, gastric ulcer after endoscopic surgery and ulcerative colitis. In addition, several molecules have been identified as therapeutic targets of rebamipide to explain its pleiotropic pharmacological actions. The aim of this article is to provide an update on the pharmacological and clinical profile of rebamipide and to explore further possibilities for additional indications.

A Review of Anti-Inflammatory Drug-Induced Gastrointestinal Injury: Focus on Prevention of Small Intestinal Injury

Capsule endoscopy and balloon endoscopy, advanced modalities that allow full investigation of the entire small intestine, have revealed that nonsteroidal anti-inflammatory drugs (NSAIDs) can cause a variety of abnormalities in the small intestine. Recently, several reports show that traditional NSAIDs (tNSAIDs) and acetylsalicylic acid (ASA) can induce small intestinal injuries. These reports have shown that the preventive effect of proton pump inhibitors (PPIs) does not extend to the small intestine, suggesting that concomitant therapy may be required to prevent small intestinal side effects associated with tNSAID/ASA use. Recently, several randomized controlled trials used capsule endoscopy to evaluate the preventive effect of mucoprotective drugs against tNSAID/ASA-induced small intestinal injury. These studies show that misoprostol and rebamipide reduce the number and types of tNSAID-induced small intestinal mucosal injuries. However, those studies were limited to a small number of subjects and tested short-term tNSAID/ ASA treatment. Therefore, further extensive studies are clearly required to ascertain the beneficial effect of these drugs.

Clinical trial: rebamipide promotes gastric ulcer healing by proton pump inhibitor after endoscopic submucosal dissection--a randomized controlled study

BACKGROUND

Endoscopic submucosal dissection (ESD) is useful for treating gastric tumors. Several trials have shown the efficacy of 4 or 8 weeks of proton pump inhibitor (PPI) administration for post-ESD ulcers. However, if the size of the post-ESD ulcer is larger than predicted, PPI administration alone might not be sufficient for the ulcer to heal within 4 weeks. We examined the efficacy of a combination therapy of PPI and rebamipide, a mucosal-protective antiulcer drug, on the acceleration of post-ESD ulcer healing.

METHODS

Patients were randomly assigned to either the PPI and rebamipide therapy or the PPI alone. Sixty-two consecutive patients with gastric tumors gave informed consent for enrolling in the study. In all cases, the estimated size of the post-ESD ulcer was larger than 20 mm. Oral administration of the drug was started on the 2nd day post-ESD and continued to the 28th day.

RESULTS

All patients received the assigned pharmaceuticals and adhered well to the treatment regimen for 28 days. The endpoint ulcers reached S1 (scar stage) in 11/31 (36%) patients in the PPI-only group and in 21/31 (68%) in the combination group (P = 0.010).

CONCLUSIONS

The combination of PPI plus rebamipide was more effective than the PPI alone for treating ulcers larger than 20 mm within 4 weeks after ESD.

Present status and strategy of NSAIDs-induced small bowel injury

Non-steroidal anti-inflammatory drugs (NSAIDs) are well known to cause gastroduodenal mucosal lesions as an adverse effect. Recently, the serious problem of NSAID-induced small intestinal damage has become a topic of great interest to gastroenterologists, since capsule endoscopy and balloon enteroscopy are available for the detection of small intestinal lesions. Such lesions have been of great concern in clinical settings, and their treatment and prevention must be devised as soon as possible. The prevalence of NSAIDs-induced small intestinal injury is higher than had been expected. Recent studies show that more than 50% of patients taking NSAIDs have some mucosal damage in the small intestine. The gross appearance of NSAID-induced enteropathy varies, appearing variously as diaphragm-like strictures, ulcers, erosions, and mucosal redness. To investigate NSAID-induced enteropathy, and to rule out other specific enteropathies, other useful methods (in addition to capsule endoscopy and balloon enteroscopy) include such modalities as radiological examination of the small intestine, the permeability test, scintigraphy or the fecal excretion test using (111)Indium-labeled white blood cells, and measurement of the fecal calprotectin concentration. Diaphragm-like strictures and bleeding from mucosal breaks may be treatable with interventional enteroscopy. Misoprostol, metronidazole, and sulfasalazine are frequently used to treat NSAID-induced enteropathy, but have undesirable effects in some cases. In the experimental model, we confirmed that several existing drugs for gastroduodenal ulcers prevented indomethacin-induced small intestinal injury. Such drugs may be useful for preventing the adverse effects of NSAIDs not only in the stomach but also in the small intestine. We hope to examine these drugs in future clinical studies.

Advance in gastroduodenal mucosal defense

The gastrointestinal tract has developed multiple mechanisms of protection from intrinsic and extrinsic injury, including but not limited to drugs, ischemic/reperfusion injuries, and infections such as Helicobacter pylori. These range from mucosal blood flow and strengthening the epithelial barrier to luminal factors such as HCO₃- secretion and regulating epithelial cell-surface pH. We reviewed recent development in host defense against Helicobacter pylori, duodenal bicarbonate secretion, protection from nonsteroidal anti-inflammatory drugs induced gastrointestinal injury, and apoptosis, as well as newer therapies.

Rescue strategies against non-steroidal anti-inflammatory drug-induced gastroduodenal damage

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed drugs worldwide, which attests to their efficacy as analgesic, antipyretic and anti-inflammatory agents as well as anticancer drugs. However, NSAID use also carries a risk of major gastroduodenal events, including symptomatic ulcers and their serious complications that can lead to fatal outcomes. The development of "coxibs" (selective cyclooxygenase-2 [COX-2] inhibitors) offered similar efficacy with reduced toxicity, but this promise of gastroduodenal safety has only partially been fulfilled, and is now dented with associated risks of cardiovascular or intestinal complications. Recent advances in basic science and biotechnology have given insights into molecular mechanisms of NSAID-induced gastroduodenal damage beyond COX-2 inhibition. The emergence of newer kinds of NSAIDs should alleviate gastroduodenal toxicity without compromising innate drug efficacy. In this review, novel strategies for avoiding NSAID-associated gastroduodenal damage will be described.

Rebamipide, a cytoprotective drug, increases gastric mucus secretion in human: evaluations with endoscopic gastrin test

We have previously developed a rapid, simple endoscopic method for evaluating gastrin-stimulated maximal acid output (the endoscopic gastrin test, EGT). In EGT, gastric fluid newly secreted over 10 min after gastrin stimulation is collected under direct endoscopic visualization. In this study, employing the EGT, we evaluated the effect of rebamipide, a cytoprotective anti-ulcer drug, on gastric mucus secretion. In ten Helicobacter pylori-negative healthy volunteers, gastric juice was collected by EGT prior to and after 4-week administration of rebamipide. The collected gastric juice was subjected to analysis for gastric mucus output. Total gastric mucin output was significantly increased by 53% by rebamipide administration from 3.2 +/- 1.2 mg hexose/10 min to 4.9 +/- 2.2 mg hexose/10 min (P < 0.01). Further analysis by ion-exchange chromatography revealed that rebamipide administration induced a specific increase in acidic mucin rich in sialic acid. Applying EGT, this study demonstrated that rebamipide administration increased gastric mucus secretion in human.

Hepatoprotective effects of misoprostol and silymarin on carbon tetrachloride-induced hepatic damage in rats

The aim of this study was to investigate the effect of misoprostol, silymarin or the co-administration of misoprostol + silymarin on the carbon tetrachloride (CCl(4))-induced hepatic injury in rats. Misoprostol (10, 100, 1000 microg/kg), silymarin (25 mg/kg) or misoprostol (100 microg/kg) + silymarin (25 mg/kg) was given once daily orally simultaneously with CCl(4) and for 15 days thereafter. The results showed that misoprostol (10, 100 or 1000 microg/kg) conferred significant protection against the hepatotoxic actions of CCl(4) in rats, reducing serum alanine aminotransferase (ALT) levels by 24.7%, 42.6% and 49.4%, respectively compared with controls. Misoprostol, given at 100 or 1000 microg/kg, decreased aspartate aminotransferase (AST) by 28 and 43.6% and alkaline phosphatase (ALP) by 19.3% and 53.4% respectively. Meanwhile, silymarin reduced ALT, AST and ALP levels by 62.7%, 66.1% and 65.1% respectively. The co-administration of misoprostol (100 microg/kg) and silymarin (25 mg/kg) resulted in 61.4%, 66.1% and 57.5% reduction in ALT, AST and ALP levels respectively. Histopathological alterations and depletion of hepatocyte glycogen and DNA content by CCl(4) were markedly reduced after treatment with misoprostol, silymarin or misoprostol + silymarin. Image analysis of liver specimens revealed a marked reduction in liver necrosis; area of damage: 32.4%, 24% and 10.2% after misoprostol (10, 100 or 1000 microg/kg), 7.2% after silymarin and 10.9% after treatment with misoprostol 100 microg/kg + silymarin, compared with CCl(4) control group (46.7%). These results indicate that treatment with misoprostol protects against hepatocellular necrosis induced by CCl(4). This study suggests a potential therapeutic use for misoprostol in liver injury.

Intestinal permeability in the pathogenesis of NSAID-induced enteropathy

BACKGROUND

The pathogenesis of nonsteroidal antiinflammatory drug (NSAID)-induced small bowel disease suggests that increased intestinal permeability is the central mechanism that translates biochemical damage to tissue damage. The purpose of this review is to summarize studies on the effect of NSAIDs to increase intestinal permeability in humans and methods for limiting this effect.

METHODS

A Medline search was made for papers that described measurements of increased intestinal permeability in humans.

RESULTS

Virtually all studies agree that all conventional NSAIDs increase intestinal permeability in the human within 24 h of ingestion and that this is equally evident when they are taken long term. Various methods have been tried to limit the damage. The most promising agents are coadministration of synthetic prostaglandins, micronutrients, pre-NSAIDs, and COX-2 selective agents. However, their efficacy in preventing the development of NSAID enteropathy in the long term has not been studied in detail, and, in the case of COX-2 selective agents, small bowel damage is comparable to that which is seen with conventional NSAIDs.

CONCLUSIONS

NSAID enteropathy is associated with significant morbidity and occasionally mortality. There are no proven effective ways of preventing this damage. Because increased intestinal permeability appears to be a central mechanism in the pathogenesis of NSAID enteropathy, it becomes a potential therapeutic target for prevention. At present there are a number of ways to limit the increased permeability, but additional studies are required to assess if this approach reduces the prevalence and severity of NSAID enteropathy.

Gastroduodenal mucosal defense

PURPOSE OF REVIEW

The gastrointestinal tract has developed multiple mechanisms of protection from intrinsic and extrinsic sources of injury, including but not limited to drugs, ischemic/reperfusion injuries, and infections such as Helicobacter pylori. We review recent developments in host defense against Helicobacter pylori, duodenal bicarbonate secretion, protection from nonsteroidal anti-inflammatory drug induced gastrointestinal injury, and apoptosis, as well as newer therapies.

RECENT FINDINGS

Leptin and survivin confer protection against ethanol and indomethacin induced injury. Mucin-1, a cell surface mucin, is an important barrier to gastrointestinal infection. Prostaglandin E(2), Escherichia coli heat-stable enterotoxin, orexins, and carbonated beverages stimulate duodenal bicarbonate secretion.

SUMMARY

Gastroduodenal mucosal defense is a dynamic process, and further insights into these defense mechanisms have and will lead to safer and more effective treatments.

Efficacy of rebamipide for diclofenac-induced small-intestinal mucosal injuries in healthy subjects: a prospective, randomized, double-blinded, placebo-controlled, cross-over study

BACKGROUND

Although obscure gastrointestinal bleeding cannot be detected by colonoscopy or upper endoscopy, wireless video capsule endoscopy (VCE) is capable of imaging it. Few data are available on medical therapy for patients with nonsteroidal anti-inflammatory drug (NSAID)-induced small-intestinal mucosal injuries. The aim of this study was to compare prevention by rebamipide and placebo of NSAID-induced smallintestinal injury in healthy subjects.

METHODS

Ten healthy subjects who provided written informed consent were enrolled. Rebamipide or placebo plus diclofenac was administered with omeprazole for 7 days, and for an additional 7-day period with treatments reversed in the same subjects, with a 4-week washout period between treatments. VCE of the small intestine was performed four times, before and after each of the two study periods.

RESULTS

The number of subjects with small-intestinal mucosal injuries was higher in the placebo group (8/10) than in the rebamipide group (2/10) (P = 0.023). Two cases of ulcer and one of bleeding were observed in the placebo group, while no ulcer or bleeding was observed in the rebamipide group.

CONCLUSIONS

Rebamipide had significantly higher efficacy than placebo in preventing NSAID-induced small-intestinal mucosal injury.

Systematic review: ulcer definition in NSAID ulcer prevention trials

BACKGROUND

In clinical trials of peptic ulcer prevention, the most appropriate definition of an ulcer remains challenging.

AIMS

To evaluate the ulcer definitions used in clinical trials of ulcer prevention among non-steroidal anti-inflammatory drug users and to determine whether any specific definition is preferred.

METHODS

A systematic literature search of the PubMed, Medline and EMBASE databases was conducted. Results were limited to full papers published in English from June 1987 to June 2007 that met the following criteria: randomized, controlled non-steroidal anti-inflammatory drug trials of > or =8 weeks' duration, with a primary end point of ulcer upon endoscopy.

RESULTS

Forty five publications met the inclusion criteria and were reviewed. Overall, an ulcer diameter of > or =3 mm was used in 25 publications and most included a description of ulcer depth. Of the remainder, ulcer was defined as any lesion with unequivocal/observable depth (with no lower limit for ulcer diameter; five publications) or an excavated mucosal break >3 mm (one publication), whereas nine defined a minimum ulcer size of > or =5 or >5 mm. Ulcer definition was unclear in the remaining five publications.

CONCLUSION

In clinical trials of ulcer prevention among non-steroidal anti-inflammatory drug users, a gastric or duodenal lesion > or =3 mm in diameter with significant depth is the preferred definition.