Rebamipide, a novel antiulcer agent, attenuates Helicobacter pylori induced gastric mucosal cell injury associated with neutrophil derived oxidants

Further insights into the impact of rebamipide on gentamicin-induced nephrotoxicity in rats: modulation of SIRT1 and β-catenin/cyclin D1 pathways

Gentamicin (GM) is an effective antibiotic administered to treat acute Gram-negative infections. Nevertheless, its clinical application is limited due to nephrotoxicity. Therefore, our research aimed to investigate the potential renoprotective impact of rebamipide (RBM), a gastroprotective drug, on GM-induced kidney damage in rats, as well as putative nephroprotective pathways. RBM was orally administered (100 mg/kg/d for 14 d) commencing 7 d before the administration of GM (100 mg/kg/d, intraperitoneally). Nephrotoxicity was elucidated, and the silent information regulator 1 (SIRT1) and β-catenin/cyclin D1 pathways were assessed. GM induced a significant elevation in the serum levels of creatinine, blood urea nitrogen (BUN), and kidney injury molecule-1 (KIM-1), as well as the relative kidney index. In addition, GM increased lipid peroxidation and lowered total antioxidant capacity (TAC) level and superoxide dismutase (SOD) activity. GM administration also demonstrated a significant amplification in tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), nuclear factor-κappa B p65 (NF-κB p65), p38 mitogen-activated protein kinase (p38 MAPK), and caspase-3 kidney levels, as well as B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax)/Bcl-2 ratio. Notably, RBM treatment amended all these changes induced by GM. Furthermore, the potential role of SIRT1 and β-catenin-dependent signaling pathways in GM-induced renal injury was assessed. Our findings showed that GM-treated rats demonstrated a substantial decrease in SIRT1, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) along with an increase in β-catenin, forkhead box O-3a (FOXO-3a), and cyclin D1 protein expressions. RMB treatment markedly attenuated the deterioration caused by GM on these pathways. Additionally, RBM alleviated the GM-induced deleterious kidney tissue histopathology. In conclusion, our findings have verified that RBM can halt GM-induced renal injury by partly modulating SIRT1 and β-catenin pathways.

Intratumor microbiota: a novel tumor component

Bacteria have been found in tumors for over 100 years, but the irreproducibility of experiments on bacteria, the limitations of science and technology, and the contamination of the host environment have severely hampered most research into the role of bacteria in carcinogenesis and cancer treatment. With the development of molecular tools and techniques (e.g., macrogenomics, metabolomics, lipidomics, and macrotranscriptomics), the complex relationships between hosts and different microorganisms are gradually being deciphered. In the past, attention has been focused on the impact of the gut microbiota, the site where the body's microbes gather most, on tumors. However, little is known about the role of microbes from other sites, particularly the intratumor microbiota, in cancer. In recent years, an increasing number of studies have identified the presence of symbiotic microbiota within a large number of tumors, bringing the intratumor microbiota into the limelight. In this review, we aim to provide a better understanding of the role of the intratumor microbiota in cancer, to provide direction for future experimental and translational research, and to offer new approaches to the treatment of cancer and the improvement of patient prognosis.

Crystal structure of the apurinic/apyrimidinic endonuclease XthA (HP1526 protein) from Helicobacter pylori

Helicobacter pylori is a bacterium that causes gastritis, peptic ulcer disease and adenocarcinoma while infecting human stomach. In the stomach H. pylori is under stresses caused by reactive oxygen and nitrogen species from host immune response, which causes oxidative DNA damage. The DNA damage in single base is repaired by base excision repair (BER) and/or nucleotide incision repair (NIR) pathways. H. pylori retains a minimal set of enzymes involved in the BER and NIR pathways. The HP1526 protein is a single apurinic/apyrimidinic (AP) endonuclease homologous to E. coli Xth protein but little is known for its structure up to now. In this study, the structure of the recombinant HP1526 protein from H. pylori (HpXthA) has been determined at a high resolution of 1.84 Å. From the structural analysis the HpXthA was found to belong to the Xth-like AP endonuclease family carrying the common fold of a central bilayer β-sheet flanked by α-helices with a divalent metal ion bound. A Mn²⁺ ion and a 1,3-butanediol were unusually found and modeled around the active site. Structural and sequence comparisons among the AP endonucleases show well-conserved residues for metal and DNA binding and for catalysis. Interestingly, the presence of a small polar residue Ser201 of the HpXthA commonly found in NIR-proficient AP endonucleases instead of an aspartate residue in NIR-deficient enzymes suggests that the HpXthA retain a nucleotide incision repair activity.

[Pharmacokinetics and pharmacodynamics of rebamipide. New possibilities of therapy: A review]

The MedLine database contains 570 publications, including 71 randomized clinical trials and 6 meta-analyses on the rebamipide molecule in 2022. Indications for the use of rebamipide are gastric ulcer, chronic gastritis with hyperacidityin the acute stage, erosive gastritis, prevention of damage to the gastrointestinal mucosa while taking non-steroidal anti-inflammatory drugs, eradication of Helicobacter pylori. Currently trials are studying the efficacy and safety of the drug in gouty and rheumatoid arthritis, osteoarthritis, Sjögren's syndrome, bronchial asthma, vitiligo, atherosclerosis, diseases of the kidneys and liver; using in traumatology to accelerate bone regeneration; in ophthalmology to improve the regeneration of corneal epithelium; in oncology to reduce inflammatory changes in the oral mucosa after chemoradiotherapy. The review article is about the main pharmacokinetic and pharmacodynamic characteristics of rebamipide. A detailed understanding of pharmacodynamics and pharmacokinetics allows for individual selection of therapy based on the characteristics of the patient's body - gender, age, comorbidities; choose the optimal route of administration and dosing regimen; predict adverse effects and drug interactions; be determined with new clinical indications.

Bioinformatics analysis of adhesin-binding potential and ADME/Tox profile of anti-Helicobacter pylori peptides derived from wheat germ proteins

Anti-adhesive activity of wheat germ-derived peptides, which is considered as one of the promising strategies for preventing Helicobacter pylori infection, was investigated. The underlying mechanism of anti-adhesive action was due to peptides acting as receptor analogues and binding to H. pylori adhesin proteins. However, there is lack of information on the nature and strength of this molecular interaction as well as the participating species and drug-likeness of the food-derived bioactive peptides. In this study, the biostability and ADME/Tox (absorption, distribution, metabolism, excretion and toxicity) profile of the anti-adhesive peptides were analyzed using bioinformatic tools, and their binding potential to H. pylori's adhesins estimated by molecular docking. Binding is facilitated by mostly hydrogen bonding and hydrophobic interaction occurring in the active site of the adhesin proteins with affinities ranging from -6.0 to -7.4 and -6.0 to -7.8 kcal/mol for BabA and SabA, respectively. The results indicate highly possible binding capabilities of the peptides to adhesin proteins. Out of 16 peptides studied, 14 bound in the vicinity of the active site of BabA and SabA whereas two different peptides demonstrated allosteric binding. The most hydrophobic peptide, P210 showed strong binding affinity for both BabA and SabA and, therefore, predicted to be the most promising peptide for further development in the prevention, management and treatment of H. pylori infection. The selected peptides were shown to be non-toxic, and to have high potential of localized effect of interfering with bacterial adherence. This work provides insights into the anti-adhesive mechanism of peptides and new evidence demonstrating bioactive peptides as promising nutraceutical candidates for preventing H. pylori infection.

Risk of Post-Myocardial Infarction Pneumonia with Proton Pump Inhibitors, H2 Receptor Antagonists and Mucoprotective Agents: A Retrospective Nationwide Cohort Study

Patients with myocardial infarction (MI) are at high risk of developing pneumonia. Proton pump inhibitors (PPI) and H2-receptor antagonists (H2RA) are commonly used acid-suppressive medications to the patients with MI for gastrointestinal (GI) protection, which may increase the risk for pneumonia. We evaluated whether PPI, H2RA, and mucoprotective agents without anti-acid properties increase the risk of post-MI pneumonia. We performed a retrospective cohort study based on the National Health Insurance Service—National Sample Cohort in Korea. The study included 3701 patients discharged with MI without prior history of pneumonia. During follow-up, treatments with PPI, H2RA, and mucoprotective agents were collected as time-dependent variables based on the prescription records. We performed multivariate time-dependent Cox regression analyses for the development of post-MI pneumonia. During the mean 4.85 ± 3.75 years follow-up, 999 participants developed pneumonia. In the multivariate analyses (adjusted hazard ratio; 95% confidence interval), the risk for pneumonia was significantly increased in treatment with PPI (2.25; 1.57–3.21) and H2RA (1.50; 1.16–1.93). Meanwhile, the risk for pneumonia was not increased in treatment with mucoprotective agents. When we evaluated GI bleeding event according to the medications as a secondary outcome analysis, mucoprotective agents were associated with increased GI bleeding risk, but PPI and H2RA were not. In the use of the GI medications in the treatment of patients with MI, the influence of these drugs on bleeding and pneumonia should be considered.

Impact of the Gut Microbiota Balance on the Health-Disease Relationship: The Importance of Consuming Probiotics and Prebiotics

Gut microbiota is a group of microorganisms that are deposited throughout the entire gastrointestinal tract. Currently, thanks to genomic tools, studies of gut microbiota have pointed towards the understanding of the metabolism of important bacteria that are not cultivable and their relationship with human homeostasis. Alterations in the composition of gut microbiota could explain, at least in part, some epidemics, such as diabetes and obesity. Likewise, dysbiosis has been associated with gastrointestinal disorders, neurodegenerative diseases, and even cancer. That is why several studies have recently been focused on the direct relationship that these types of conditions have with the specific composition of gut microbiota, as in the case of the microbiota-intestine-brain axis. In the same way, the control of microbiota is related to the diet. Therefore, this review highlights the importance of gut microbiota, from its composition to its relationship with the human health-disease condition, as well as emphasizes the effect of probiotic and prebiotic consumption on the balance of its composition.

Dietary Cameroonian Plants Exhibit Anti-Inflammatory Activity in Human Gastric Epithelial Cells

In Cameroon, local plants are traditionally used as remedies for a variety of ailments. In this regard, several papers report health benefits of Cameroonian spices, which include antioxidant and anti-microbial properties, whereas gastric anti-inflammatory activities have never been previously considered. The present study investigates the antioxidant and anti-inflammatory activities of hydro-alcoholic extracts of eleven Cameroonian spices in gastric epithelial cells (AGS and GES-1 cells). The extracts showed antioxidant properties in a cell-free system and reduced H₂O₂-induced ROS generation in gastric epithelial cells. After preliminary screening on TNFα-induced NF-κB driven transcription, six extracts from Xylopia parviflora, Xylopia aethiopica, Tetrapleura tetraptera, Dichrostachys glomerata, Aframomum melegueta, and Aframomum citratum were selected for further studies focusing on the anti-inflammatory activity. The extracts reduced the expression of some NF-κB-dependent pro-inflammatory mediators strictly involved in the gastric inflammatory process, such as IL-8, IL-6, and enzymes such as PTGS2 (COX-2), without affecting PTGS1 (COX-1). In conclusion, the selected extracts decreased pro-inflammatory markers by inhibiting the NF-κB signaling in gastric cells, justifying, in part, the traditional use of these spices. Other molecular mechanisms cannot be excluded, and further studies are needed to better clarify their biological activities at the gastric level.

The effectiveness of rebamipide mouthwash therapy for radiotherapy and chemoradiotherapy-induced oral mucositis in patients with head and neck cancer: a systematic review and meta-analysis

Background

Oral mucositis is a frequent and severe adverse event in patients undergoing chemoradiotherapy for head and neck cancers, especially grade 3 or 4 mucositis. Occurrence may result in drop-out from treatment, thereby reducing survival. We aimed to clarify the effectiveness and safety of rebamipide mouthwash for oral mucositis in patients with head and neck cancer receiving treatment.

Methods

We carried out a systematic review and meta-analysis of patients with head and neck cancer who were treated with rebamipide mouthwash. We searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL), and the World Health Organization (WHO) International Clinical Trial Registry Platform. The primary outcome was the incidence of severe oral mucositis, and secondary outcomes were time from treatment start to onset of oral mucositis, the response rate of radiotherapy, and any adverse events.

Results

We included three studies comparing rebamipide versus placebo, all of which evaluating chemoradiotherapy induced oral mucositis. The chemotherapeutic agent was docetaxel in one study and cisplatin in the remaining two. Radiotherapy in each study consisted of 3D-conformal radiation therapy, intensity modulated radiation therapy and conventional radiation therapy, respectively. The calculated odds ratio was 0.29 [95% confidence interval (CI): 0.15 to 0.55], showing a positive association in the three studies between the incidence of grade 3–4 oral mucositis and chemotherapy for head and neck cancer. One study reported an onset of oral mucositis and the time to onset was 14.6 ± 6.4 days for the rebamipide group and 11.2 ± 4.4 days for placebo. One study reported a complete response of 8.3% for placebo and 16.7% for the rebamipide the group, and the partial response was 91.7 and 75.0%, respectively. Adverse events were reported in two studies to be 6.1 and 11.6% for placebo, and 19.4 and 26.0% in the rebamipide group, respectively.

Conclusions

Rebamipide mouthwash is effective in the prevention of severe mucositis and stomatitis. However, evaluation of adverse events in observational studies are needed.

Risk of post-stroke pneumonia with proton pump inhibitors, H2 receptor antagonists and mucoprotective agents: A retrospective nationwide cohort study

Stroke patients are at high risk of developing pneumonia, which is major cause of post-stroke mortality. Proton pump inhibitors and H₂ receptor antagonists are anti-ulcer drugs, which may predispose to the development of pneumonia by suppression of the gastric acid with bactericidal activity. Unlike proton pump inhibitors and H₂ receptor antagonists, mucoprotective agents have gastroprotective effects with no or less anti-acid property. We aimed to investigate effects of the acid-suppressive medications (proton pump inhibitors and H₂ receptor antagonists) and mucoprotective agents on risk for post-stroke pneumonia using the National Health Insurance Service-National Sample Cohort in Korea. This retrospective cohort study included 8,319 patients with acute ischemic stroke. Use of proton pump inhibitors, H₂ receptor antagonists, and mucoprotective agents (rebamipide, teprenone, irsogladine, ecabet, polaprezinc, sofalcone, sucralfate, and misoprostol) after stroke were determined based on the prescription records, which were treated as time-dependent variables. Primary outcome was the development of post-stroke pneumonia. During the mean follow-up period of 3.95 years after stroke, 2,035 (24.5%) patients had pneumonia. In the multivariate time-dependent Cox regression analyses (adjusted hazard ratio [95% confidence interval]), there was significantly increased risk for pneumonia with use of proton pump inhibitors (1.56 [1.24–1.96]) and H₂ receptor antagonists (1.40 [1.25–1.58]). In contrast to the proton pump inhibitors and H₂ receptor antagonists, use of mucoprotective agents did not significantly increase the risk for pneumonia (0.89 [0.78–1.01]). In conclusion, the treatment with proton pump inhibitors and H₂ receptor antagonists was associated with increased risk for pneumonia in stroke patients. Clinicians should use caution in prescribing the acid-suppressive medications for the stroke patients at great risk for pneumonia.

Role of mucoprotective agents in endoscopic submucosal dissection-derived ulcers: A systematic review

BACKGROUND

Currently, it is still unclear whether adding a mucoprotective agent to a proton pump inhibitor (PPI) results in better outcomes compared with using a PPI alone in patients with post-gastric endoscopic submucosal dissection (ESD) ulcers. This study aimed to examine the efficacy of PPI alone versus combination treatment in healing of post-gastric ESD ulcers, as well as on delayed bleeding and amount of blood transfused.

METHODS

A systematic search of MEDLINE, EMBASE, Cochrane, and ISI Web of knowledge databases, up until May 2017, for randomized trials comparing PPI alone versus PPI plus a mucoprotective drug in achieving ulcer healing in patients undergoing gastric ESD was performed. The primary outcome is scarring stage on endoscopic assessment at 4 or 8 weeks after gastric ESD.

RESULTS

From an initial 3071 citations, eight articles (n = 953 lesions from 934 patients) were analyzed. Patients receiving combination treatment achieved a scarring stage significantly more often than those on a PPIs alone at 4 or 8 weeks after ESD, (risk ratio = 1.36, 95% CI; 1.06-1.75). No study reported amount of blood transfused. There were no significant between treatment-group differences in terms of delayed bleeding (risk ratio = 0.58, 95% CI; 0.17-1.99). Neither location of ulcer nor Helicobacter pylori infection was related to ulcer scarring stage.

CONCLUSION

The limited evidences suggested combination treatment may be more effective in accelerating the process of ulcer healing in patients undergoing gastric ESD than the use of PPI alone, but does not appear to alter delayed bleeding risk.

Molecular Mechanisms of H. pylori-Induced DNA Double-Strand Breaks

Infections contribute to carcinogenesis through inflammation-related mechanisms. H. pylori infection is a significant risk factor for gastric carcinogenesis. However, the molecular mechanism by which H. pylori infection contributes to carcinogenesis has not been fully elucidated. H. pylori-associated chronic inflammation is linked to genomic instability via reactive oxygen and nitrogen species (RONS). In this article, we summarize the current knowledge of H. pylori-induced double strand breaks (DSBs). Furthermore, we provide mechanistic insight into how processing of oxidative DNA damage via base excision repair (BER) leads to DSBs. We review recent studies on how H. pylori infection triggers NF-κB/inducible NO synthase (iNOS) versus NF-κB/nucleotide excision repair (NER) axis-mediated DSBs to drive genomic instability. This review discusses current research findings that are related to mechanisms of DSBs and repair during H. pylori infection.

Efficacy and safety of the use of rebamipide in the scheme of triple eradication therapy of Helicobacter pylori infection: a prospective randomized comparative study

Purpose of the study. To evaluate the effectiveness and safety of the use of rebamipide as part of the triple eradication therapy (ET) scheme of Helicobacter pylori infection. Materials and methods. A prospective, randomized comparative study included 94 patients with uncomplicated H. pylori-associated stomach / duodenal ulcer. In the process of randomization, patients are divided into three groups depending on the intended therapy. The first group (n=36) received a classical triple scheme of the first-line ET (omeprazole 20 mg twice a day, amoxicillin 1000 mg twice a day, clarithromycin 500 mg twice a day) for 10 days. Patients of the second group (n=33) were assigned a classical triple scheme of ET with the inclusion of rebamipide (omeprazole 20 mg twice a day, amoxicillin 1000 mg twice a day, clarithromycin 500 mg twice a day, rebamipide 100 mg 3 times a day day) for 10 days. Patients of the third group (n=25) were assigned a classical triple scheme of ET with the inclusion of rebamipide (omeprazole 20 mg twice a day, amoxicillin 1000 mg twice a day, clarithromycin 500 mg twice a day, rebamipide 100 mg 3 times a day) in for 10 days, with the prolongation of the administration of rebamipide for the next 20 days. The effectiveness of ET was determined by the respiratory test after 6 weeks after the end of treatment. Adverse events were recorded by patients in specially developed diaries. All patients with gastric ulcer at the 6th week underwent a histological examination of the biopsy specimens of the antrum and the body of the stomach, assessing the inflammatory activity of the process on a point system in accordance with the updated Sydney system. Results and discussion. Efficiency of H. pylori eradication in the first group was 77.7% (ITT), 82.3% (PP), in the second group - 81.8% (ITT), 84.4% (PP), and in the third group - 84% (ITT), 87.5% (PP). The use of rebamipide in the triple ET regimen was associated with an increase in H. pylori eradication efficiency, both with simultaneous use with the scheme [odds ratio (OR) 1.16; 95% confidence interval (CI) 0.32-4.24], and with subsequent prolonged admission (OR 1.5, 95% CI 0.34-6.7). A somewhat more pronounced dynamics of the epithelization of erosive and ulcerative changes in the mucous membrane of the stomach and duodenum to the 21st and 28th days in the third group of patients was noted. The incidence of adverse events between the groups was comparable: 22.2% in the first group, 24.2% in the second group and 20% in the third group. In the pathomorphological evaluation of biopsy specimens of patients with gastric ulcer at the 6th week after the treatment, significant differences were revealed between the first and third groups in terms of the inflammatory activity in the antrum stomach (2±0.63 vs. 1.4±0.52; p=0,0399). The conclusion. The inclusion of rebamipide in the classical triple scheme of H. pylori ET increases the effectiveness of treatment and does not affect the safety profile. In the post-eradication period, it is advisable to continue the use of rebamipide to potentiate the repair of the gastric mucosa and regress the inflammatory processes.

[The Efficacy of Rebamipide or Ecabet Sodium Supplementation for Helicobacter pylori Eradication Therapy Compared with Quadruple (Concomitant) Regimen]

Background/Aims

Although some previous studies reported that a treatment combined with mucoprotective agent could improve the eradication rate in dual or triple therapy, there are other reports that question the efficacy of combining these drugs in concomitant therapy (CoCTx). The aim of this study was to investigate the effects of rebamipide or ecabet on the Helicobacter pylori (H. pylori) eradication combined with CoCTx.

Methods

We retrospectively reviewed the medical records of 277 patients with proven H. pylori infection. They were assigned to one of 3 regimens for 10 days, twice daily: (a) CoCTx (n=118): lansoprazole 30 mg, amoxicillin 1 g, metronidazole 500 mg, and clarithromycin 500 mg; (b) CoCTx+rebamipide (100 mg) (n=85); (c) CoCTx+ecabet (1 g) (n=74).

Results

The baseline characteristics were not significantly different. H. pylori eradication rates were 82.2% (97/118) in CoCTx, 90.6% (77/85) in CoCTx+rebamipide, and 89.2% (66/74) in CoCTx+ecabet (p=0.17), which were statistically insignificant. Overall adverse events were more frequently reported in the CoCTx+rebamipide (50.6%. 43/85) and CoCTx+ecabet (44.6%, 33/74) groups than in the CoCTx (32.2%, 38/118) (p = 0.03) group. Drug compliances were not different between three groups (CoCTx: 95.8%, 113/118; CoCT+rebamipide: 92.9%, 79/85; CoCTx+ecabet 98.6%,73/74) (p=0.209). Multivariate analysis showed that the risk of eradication failure was significantly increased with decreased drug compliance (odds ratio 3.52, 95% confidence interval 1.00-12.32; p=0.05).

Conclusions

Addition of these mucoprotective agent was not superior to CoCTx alone for eradicating H. pylori infection with frequent adverse events. Rather, drug compliance is the most related factor affecting the eradication rate. Our data suggest the importance of drug compliance over the drugs used.

Do Cyclosporine A, an IL-1 Receptor Antagonist, Uridine Triphosphate, Rebamipide, and/or Bimatoprost Regulate Human Meibomian Gland Epithelial Cells?

PURPOSE

Researchers have hypothesized that treatment with cyclosporine A (CyA), interleukin-1 receptor antagonists (IL-1RA; e.g., anakinra), P2Y2 receptor agonists (e.g., uridine triphosphate; UTP), and rebamipide may alleviate human meibomian gland dysfunction (MGD) and/or dry eye disease. Investigators have also proposed that prostaglandin analogues (e.g., bimatoprost) may induce MGD. Our goal was to determine whether these compounds directly influence human meibomian gland epithelial cell (HMGEC) function.

METHODS

Multiple concentrations of each compound were tested for effects on immortalized (I) HMGEC morphology and survival. Nontoxic dosages were used for our studies. Immortalized HMGEC were cultured in the presence of vehicle, CyA, IL-1RA, UTP, rebamipide, or bimatoprost for up to 6 days in various media. Experiments included positive controls for proliferation (epidermal growth factor and bovine pituitary extract), differentiation (azithromycin), and signaling pathway activation (insulin-like growth factor 1). Cells were analyzed for neutral lipid staining, lysosome accumulation, lipid composition, and phosphatidylinositol-3-kinase/Akt (AKT), phosphorylation.

RESULTS

Our findings demonstrate that CyA, IL-1RA, UTP, rebamipide, and bimatoprost had no effect on the proliferation; neutral lipid content; lysosome number; or levels of free cholesterol, triglycerides, or phospholipids in IHMGECs. Cylosporine A, IL-1RA, rebamipide, and bimatoprost significantly reduced the phosphorylation of AKT, as compared to control. Of interest, tested doses of CyA above 8 nM killed the IHMGECs.

CONCLUSIONS

Our results show that CyA, IL-1RA, UTP, rebamipide, and bimatoprost do not influence the proliferation or differentiation of IHMGEC. However, with the exception of UTP, these compounds do decrease the activity of the AKT signaling pathway, which is known to promote cell survival.

Rebamipide, an Amino Acid Analog of 2(1H)-Quinolinone, Inhibits the Formation of Human Osteoclasts

Objectives. Drug repositioning or drug reprofiling (DR) has recently been growing in importance. DR has a significant advantage over traditional drug development because the repositioned drug has already passed toxicity tests; its safety is known, and the risk of adverse toxicology is reduced. In the current study, we investigated the role of rebamipide, a mucosa-protecting agent, with recently reported anti-inflammatory function, in human osteoclastogenesis. Methods. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence of M-CSF and sRANKL. Osteoclast formation was evaluated by immunohistological staining for CD51/61 (vitronectin receptors). Osteoclast formation, in the presence or absence of rebamipide (0, 1, and 3 mM), was observed by time-lapse photography and actin ring formation. The number of absorption sites and area of absorption were calculated using Osteologic™ plates. Pit formation was studied by 3D-SEM. Results. Rebamipide inhibited human osteoclast formation at 3 mM, a pharmacological concentration, and inhibited resorbing activity dose-dependently. Rebamipide induced the degradation of actin rings in mature osteoclasts. This mechanism may involve inhibiting the osteoclast fusion pathway through reducing the expression of DC-specific transmembrane protein (DC-STAMP). Conclusions. The present study suggests that rebamipide would be useful as a novel agent for osteoporosis and rheumatoid arthritis.

Resveratrol Protects against Helicobacter pylori-Associated Gastritis by Combating Oxidative Stress

Helicobacter pylori (H. pylori)-induced oxidative stress has been shown to play a very important role in the inflammation of the gastric mucosa and increases the risk of developing gastric cancer. Resveratrol has many biological functions and activities, including antioxidant and anti-inflammatory effect. The purpose of this study was to probe whether resveratrol inhibits H. pylori-induced gastric inflammation and to elucidate the underlying mechanisms of any effect in mice. A mouse model of H. pylori infection was established via oral inoculation with H. pylori. After one week, mice were administered resveratrol (100 mg/kg body weight/day) orally for six weeks. The mRNA and protein levels of iNOS and IL-8 were assessed using RT-PCR, Western blot and ELISA. The expression levels of IκBα and phosphorylated IκBα (which embodies the level and activation of NF-κB), Heme Oxygenase-1 (HO-1; a potent antioxidant enzyme) and nuclear factor-erythroid 2 related factor 2 (Nrf2) were determined using Western blot, and lipid peroxide (LPO) level and myeloperoxidase (MPO) activity were examined using an MPO colorimetric activity assay, thiobarbituric acid reaction, and histological-grade using HE staining of the gastric mucosa. The results showed that resveratrol improved the histological infiltration score and decreased LPO level and MPO activity in the gastric mucosa. Resveratrol down-regulated the H. pylori-induced mRNA transcription and protein expression levels of IL-8 and iNOS, suppressed H. pylori-induced phosphorylation of IκBα, and increased the levels of HO-1 and Nrf2. In conclusion, resveratrol treatment exerted significant effects against oxidative stress and inflammation in H. pylori-infected mucosa through the suppression of IL-8, iNOS, and NF-κB, and moreover through the activation of the Nrf2/HO-1 pathway.

Rebamipide suppresses mite-induced asthmatic responses in NC/Nga mice

Allergic asthma caused by continuous allergen exposure evokes allergen-specific Th2 responses and is characterized by chronic airway inflammation and hyperresponsiveness. A previous report showed that rebamipide improved asthmatic symptoms in an ovalbumin/trypsin mice model. However, it is still unclear how rebamipide exerts its effects in asthma. In this study, rebamipide improved the asthmatic responses induced by mite exposure in NC/Nga mice, revealing the mechanism of this therapeutic effect. Rebamipide suppressed the infiltration of eosinophils into the airways and lung as well as attenuating the production of reactive oxygen species in tissues. In addition to these anti-inflammatory effects, rebamipide inhibited the production of IL-33, a member of the IL-1 family that drives the subsequent production of Th2-associated cytokines. These observations identify the point where rebamipide exerts its suppressive action on asthma and suggest that rebamipide has therapeutic potential in preventing mite-induced asthma.

Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.57-3.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy.

Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.57–3.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy.

Protective effects of garlic extract, PMK-S005, against nonsteroidal anti-inflammatory drugs-induced acute gastric damage in rats

BACKGROUND

PMK-S005 is synthetic s-allyl-L-cysteine (SAC), a sulfur-containing amino acid, which was initially isolated from garlic. The antioxidant and anti-inflammation activities of SAC have been demonstrated in diverse experimental animal models.

AIMS

The purpose of this study was to investigate the gastroprotective effects of PMK-S005 against NSAIDs-induced acute gastric damage in rats.

METHODS

Eight-week SD rats were pretreated with PMK-S005 (1, 5, or 10 mg/kg) or rebamipide (50 mg/kg) 1 h before administration of NSAIDs including aspirin (200 mg/kg), diclofenac (80 mg/kg), and indomethacin (40 mg/kg). After 4 h, the gross ulcer index, histological index, and gastric mucus level were determined. Myeloperoxidase (MPO), TNF-α, IL-1β, PGE2, and LTB4 levels were estimated in the gastric mucosal tissue by ELISA. Protein expressions of cPLA2, COX-1, and COX-2 were assessed by Western blot analysis.

RESULTS

Pretreatment with PMK-S005 significantly attenuated the NSAIDs-induced gastric damage and increased the gastric mucus level. In addition, PMK-S005 attenuated increases in MPO, TNF-α, and IL-1β production. The expressions of cPLA2 and COX-2 induced by NSAIDs were decreased by PMK-S005 pretreatment. PMK-S005 did not cause suppression of PGE2 synthesis induced by NSAIDs, but LTB4 production was significantly suppressed by PMK-S005. The effects of PMK-S005 were consistently maximized at a concentration of 5 mg/kg, which were frequently superior to those of rebamipide.

CONCLUSIONS

These results strongly suggest that PMK-S005 can be a useful gastroprotective agent against acute gastric mucosal damage by suppressing proinflammatory cytokines, down-regulating cPLA2, COX-2 and LTB4 expression, and increasing the synthesis of mucus.

Effect of supplementation with rebamipide for Helicobacter pylori eradication therapy: a systematic review and meta-analysis

BACKGROUND AND AIM

Several studies have reported that the application of rebamipide during the eradication of Helicobacter pylori can improve the eradication rate. However, the efficacy and safety are controversial. The present study systematically evaluated whether rebamipide improves the eradication rate of H. pylori by conducting a meta-analysis based on randomized controlled trials (RCTs).

METHODS

Literature searches were conducted in the following database: PubMed, the Cochrane Library, and the Igaku-chuo-zasshi database in Japan. A meta-analysis of all RCTs comparing rebamipide supplementation with non-rebamipide-containing therapy was performed.

RESULTS

We identified six randomized trials (611 patients). Pooled H. pylori eradication rates by per-protocol analysis were 73.3% and 61.4% for patients with or without rebamipide, respectively. The odds ratio was 1.74 (95% confidence interval. 1.19-2.53).

CONCLUSIONS

Supplementation with rebamipide might be effective in increasing the H. pylori eradication rates of proton-pump inhibitor-amoxicillin dual therapy.

Oxidative DNA Damage Response in Helicobacter pylori-Infected Mongolian Gerbils

Helicobacter pylori (H. pylori) induced DNA damage which may be related to gastric cancer development. The DNA damage response coordinates DNA repair, cell-cycle transition, and apoptosis through activation of DNA damage response molecules. The damaged DNA is repaired through non-homologous end joining (NHEJ) or homologous recombination (HR). In the present study, we investigated the changes of HR DNA repair proteins (ataxia-telangiectasia-mutated; ATM, ATM and Rad3-related; ATR), NHEJ repair proteins (Ku70/80), cell cycle regulators (Chk1, Chk2), and apoptosis marker (p53/p-p53) were determined in H. pylori-infected Mongolian gerbils. In addition, the effect of an antioxidant N-acetylcysteine (NAC) on H. pylori-induced DNA damage response was determined to assess the involvement of oxidative stress on DNA damage of the animals infected with H. pylori. One week after intragastric inoculation with H. pylori, Mongolian gerbils were fed with basal diet with or without 3% NAC for 6 weeks. After 6 week, the expression levels of DNA repair proteins (Ku70/80, ATM, ATR), cell cycle regulators (Chk1, Chk2) and apoptosis marker (p-p53/p53) were increased in gastric mucosa of Mongolian gerbils, which was suppressed by NAC treatment. In conclusion, oxidative stress mediates H. pylori-induced DNA damage response including NHEJ and HR repairing processes, cell cycle arrest and apoptosis in gastric mucosa of Mongolian gerbils.

Protective effect of Korean Red Ginseng extract against Helicobacter pylori-induced gastric inflammation in Mongolian gerbils

Helicobacter pylori-induced gastric inflammation includes induction of inflammatory mediators interleukin (IL)-8 and inducible nitric oxide synthase (iNOS), which are mediated by oxidant-sensitive transcription factor NF-κB. High levels of lipid peroxide (LPO) and increased activity of myeloperoxidase (MPO), a biomarker of neutrophil infiltration, are observed in H. pylori-infected gastric mucosa. Panax ginseng Meyer, a Korean herb medicine, is widely used in Asian countries for its biological activities including anti-inflammatory efficacy. The present study aims to investigate whether Korean Red Ginseng extract (RGE) inhibits H. pylori-induced gastric inflammation in Mongolian gerbils. One wk after intragastric inoculation with H. pylori, Mongolian gerbils were fed with either the control diet or the diet containing RGE (200 mg RGE/gerbil) for 6 wk. The following were determined in gastric mucosa: the number of viable H. pylori in stomach; MPO activity; LPO level; mRNA and protein levels of keratinocyte chemoattractant factor (KC, a rodent IL-8 homolog), IL-1β, and iNOS; protein level of phospho-IκBα (which reflects the activation of NF-κB); and histology. As a result, RGE suppressed H. pylori-induced mRNA and protein levels of KC, IL-1β, and iNOS in gastric mucosa. RGE also inhibited H. pylori-induced phosphorylation of IκBα and increases in LPO level and MPO activity of gastric mucosa. RGE did not affect viable H. pylori colonization in the stomach, but improved the histological grade of infiltration of polymorphonuclear neutrophils, intestinal metaplasia, and hyperplasia. In conclusion, RGE inhibits H. pylori-induced gastric inflammation by suppressing induction of inflammatory mediators (KC, IL-1β, iNOS), MPO activity, and LPO level in H. pylori-infected gastric mucosa.

Oxidative stress involvement and gene expression in indomethacin-induced gastropathy

It has been proposed that neutrophil- and oxygen radical-dependent microvascular injuries are important prime events that lead to gastric mucosal injury induced by indomethacin. Reactive oxygen species (ROS) produced by activated neutrophils after indomethacin treatment cause gastric mucosal injury via ROS-mediated oxidation of important biomolecules such as lipid, protein, and DNA. In addition, it has been revealed that indomethacin-induced gastric mucosal injury occurs via gastric epithelial cell apoptosis. However, there is little known about the mechanism of indomethacin-triggered cellular response and apoptotic signaling in gastric mucosal cells. In the present study, we summarize the evidence that supports the involvement of oxidative stress and apoptosis in indomethacin-induced gastropathy, and review the gene expression profiles of gastric epithelial cells after indomethacin treatment determined by DNA microarray analysis.

Rebamipide suppresses PolyI:C-stimulated cytokine production in human conjunctival epithelial cells

PURPOSE

We previously documented that ocular surface epithelial cells could regulate ocular surface inflammation and suggested that, while Toll-like receptor 3 upregulates, EP3, one of the prostaglandin E2 receptors, downregulates ocular surface inflammation. Others reported that rebamipide, a gastroprotective drug, could not only increase the gastric mucus production, but also suppressed gastric mucosal inflammation and that it was dominantly distributed in mucosal tissues. The eyedrop form of rebamipide, approved in Japan for use in the treatment of dry eye diseases, upregulates mucin secretion and production, thereby suppressing superficial punctate keratopathy on the ocular surface of patients with this disease. In the current study, we investigated whether rebamipide has anti- inflammatory effects on the ocular surface.

METHODS

To examine the effects of rebamipide on polyI:C-induced cytokine expression by primary human conjunctival epithelial cells, we used enzyme-linked immunosorbent assay and quantitative reverse transcription-polymerase chain reaction assay. We studied the effects of rebamipide on ocular surface inflammation in our murine experimental allergic conjunctivitis (EAC) model.

RESULTS

Rebamipide could suppress polyI:C-induced cytokine production and the expression of mRNAs for CXCL10, CXCL11, RANTES, MCP-1, and IL-6 in human conjunctival epithelial cells. In our EAC model, the topical administration of rebamipide suppressed conjunctival allergic eosinophil infiltration.

CONCLUSIONS

The topical application of rebamipide on the ocular surface might suppress ocular surface inflammation by suppressing the production of cytokines by ocular surface epithelial cells.

A study on the efficacy of rebamipide for patients with proton pump inhibitor-refractory non-erosive reflux disease

BACKGROUND AND AIM

Reflux symptoms in patients with non-erosive reflux disease (NERD) cannot be easily controlled by treatment with proton pump inhibitors (PPI). The anti-inflammatory function of rebamipide may be effective for protecting the esophageal mucosa. This prospective randomized multicenter placebo-controlled study was performed to clarify the efficacy of rebamipide for NERD patients whose reflux symptoms were refractory to PPI treatment.

METHODS

One hundred forty-nine patients were enrolled on the basis of a QUEST score of over 6 and absence of endoscopically proven esophageal mucosal breaks. All the patients were initially administered 15 mg of lansoprazole for 4 weeks, and the symptoms were then assessed using QUEST and GSRS. PPI-refractory patients were randomly assigned to administration of rebamipide or placebo t.i.d. for 4 weeks.

RESULTS

Three of the 149 patients were lost to follow-up, and 60 among the remaining 146 patients were found to be PPI-refractory. Among these PPI-refractory patients, 31 were randomly assigned to a rebamipide group and 29 to a placebo group. At the end of drug administration, the QUEST and GSRS scores did not differ between the rebamipide and placebo groups, although a significantly higher proportion of patients in the rebamipide group showed amelioration of abdominal pain and diarrhea.

CONCLUSION

Administration of rebamipide cannot effectively control reflux symptoms in NERD patients whose symptoms are refractory to PPI therapy.

Contributing factors to gastric ulcer healing after endoscopic submucosal dissection including the promoting effect of rebamipide

BACKGROUND

The healing process for artificial ulcers resulting from endoscopic submucosal dissection (ESD) for gastric cancer is not understood.

AIM

To clarify factors that promote healing and the additional healing effects of rebamipide, we conducted a randomized controlled trial to compare proton pump inhibitor (PPI) and combination PPI plus rebamipide treatments.

METHODS

One hundred and seventy patients with early gastric cancers that had undergone ESD were enrolled. Follow-up endoscopy was scheduled at 4-6 weeks after ESD. We assessed marginal healing and basal healing independently by endoscopic observation. Marginal healing was determined by a regenerating epithelium and/or converging folds around the periphery of the ulcer. Basal healing was declared when the ulcer was covered by white coat thinning such that basal granulation could be seen. The sizes of the artificial ulcers were divided into normal size (area <1,200 mm(2)) or large size (area ≥ 1,200 mm(2)).

RESULTS

Initial ulcer size and duration after ESD were significantly correlated with both marginal and basal healing rates by univariate analysis. The marginal healing rate of antral lesions was higher than that of body lesions. Multivariate analysis showed a large-sized ulcer was the only significant predictor of delayed healing, with delayed healing defined as no observed marginal or basal healing (p < 0.0001). Subgroup analysis for the effect of rebamipide on large-sized ulcers showed a significantly higher rate of basal healing in the combination PPI and rebamipide group (p = 0.015).

CONCLUSIONS

Healing in ESD-induced ulcers was dependent on the initial ulcer size. In large-sized ulcers, rebamipide promotes basal healing.

Roles of oxidative stress in stomach disorders

The stomach is a sensitive digestive organ that is susceptible and exposed to exogenous pathogens from the diet. In response to such pathogens, the stomach induces oxidative stress, which might be related to the development of gastric organic disorders such as gastritis, gastric ulcers, and gastric cancer, as well as functional disorders such as functional dyspepsia. In particular, the bacterium Helicobacter pylori plays a major role in eliciting and confronting oxidative stress in the stomach. The present paper summarizes the pathogenesis of oxidative stress in the stomach during the development of various stomach diseases.

What is the difference between Helicobacter pylori-associated dyspepsia and functional dyspepsia?

Advances in basic and clinical research have revealed that Helicobacter pylori (H. pylori) infection plays an important role in the development of gastroduodenal dysmotility and hypersensitivity, as also in dyspepsia symptoms. In addition, recent studies have proposed an inflammation-immunological model for the pathogenesis of functional dyspepsia. Since H. pylori is the major microbe that provokes a gastroduodenal inflammatory response, it should not be overlooked when considering the pathophysiology of dyspepsia symptoms. In fact, population-based studies have demonstrated that H. pylori is detected more frequently in dyspepsia patients. However, although many clinical studies tried to reveal the association of H. pylori infection with gastric motility dysfunction or hypersensitivity, the results have been conflicting. On the other hand, many etiological features were revealed for the development of H. pylori-associated dyspepsia, such as abnormal ghrelin or leptic secretion, altered expression of muscle-specific microRNAs, and duodenal inflammatory cell infiltration. In addition, therapeutic strategy for H. pylori-associated dyspepsia would be different from H. pylori-negative functional dyspepsia. This review focuses the issue of whether H. pylori-associated dyspepsia should be considered as a different disease entity from functional dyspepsia.

The effect of probiotics and mucoprotective agents on PPI-based triple therapy for eradication of Helicobacter pylori

BACKGROUND/AIMS

Recent studies have found that probiotics have anti-Helicobacter pylori (HP) properties. We evaluated the additive effects of (i) Saccharomyces boulardii combined with proton pump inhibitor (PPI)-based triple therapy and (ii) S. boulardii and a mucoprotective agent (DA-9601) coupled with PPI-based triple therapy for HP eradication.

METHODS

We recruited 991 HP infected patients and randomized them into one of three groups, (A) PPI-based 7-day triple therapy, (B) the same triple therapy plus S. boulardii for 4 weeks, and (C) the same 7-day triple therapy plus S. boulardii and mucoprotective agent for 4 weeks. All patients in the three groups were tested via (13)C-urea breath test 4 weeks after the completion of the therapy.

RESULTS

According to the results of an intention-to-treat analysis, HP eradication rates for the groups A, B, and C were 71.6% (237/331), 80.0% (264/330), and 82.1% (271/330), respectively (p = .003). According to the results of a per protocol analysis, the eradication rates were 80.0% (237/296), 85.4% (264/309) and, 84.9% (271/319), respectively (p = .144). The frequency of side effects in group B (48/330) and C (30/330) was lower than that in group A (63/331) (p < .05).

CONCLUSION

This study suggests that supplementation with S. boulardii could be effective for improving HP eradication rates by reducing side effects thus helping completion of eradication therapy. However, there were no significant effects on HP eradication rates associated with the addition of mucoprotective agents to probiotics and triple therapy.

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.

Preliminary trial of rebamipide for prevention of low-dose aspirin-induced gastric injury in healthy subjects: a randomized, double-blind, placebo-controlled, cross-over study

Although low-dose aspirin is widely used, since it is a cheap and effective means of prevention of cardiovascular events, it can cause hemorrhagic gastrointestinal complications. The aim of this study was to evaluate the efficacy of rebamipide in preventing low-dose aspirin-induced gastric injury. A randomized, double-blind, placebo-controlled, crossover trial was performed in twenty healthy volunteers. Aspirin 81 mg was administered with placebo or rebamipide 300 mg three times daily for 7 consecutive days. The rebamipide group exhibited significant prevention of erythema in the antrum compared with the placebo group (p = 0.0393, respectively). Results for the body and fornix did not differ significantly between the placebo and rebamipide groups. In conclusion, short-term administration of low-dose aspirin induced slight gastric mucosal injury in the antrum, but not in the body or fornix. Rebamipide may be useful for preventing low-dose aspirin-induced gastric mucosal injury, especially which confined to the antrum.

Rebamipide and mosapride enhance pilocarpine-induced salivation

BACKGROUND

During esophageal acid clearance, salivation plays an important role in defending the esophageal mucosa. Mosapride, an agent used in chronic, long-term therapy of gastro-esophageal reflux disease (GERD) was regarded as mediating its efficacy through prokinetic properties. Rebamipide is also widely used as an anti-gastritis and anti-ulcer agent in GERD patients with chronic gastritis. The aim of this study is to investigate the effects of rebamipide, mosapride, and risperidone on the salivation induced by pilocarpine.

MATERIALS AND METHODS

The experiments were conducted on 4-week male SD rats (120-150g). The salivation was induced by intraperitoneally administrated pilocarpine and saliva was collected using preweighted small cotton balls inserted into the animal's mouth every 30 min for 180 min. Thirteen minutes before intraperitoneal administration of pilocarpine, rebamipide, mosapride, and risperidone were administered intraduodenally. Control rats were conducted by intraperitoneal administration of saline and intraduodenal administration of 0.5% methylcellulose solution.

RESULTS

The saliva weight at 0-30 min was significantly (p<0.01) increased after administration of pilocarpine, compared to control rats. An additional administration of mosapride and rebamipide increased the saliva weight at 0-30 min. The total volume of saliva for 150 min after administration of pilocarpine was the highest after preadministration of rebamipide, followed by mosapride, and risperidone.

CONCLUSIONS

Increase in salivation produced by i.p. pilocarpine was enhanced by preadministration of rebamipide and mosapride.

An open-labeled study of rebamipide treatment in chronic gastritis patients with dyspeptic symptoms refractory to proton pump inhibitors

To assess the efficacy of rebamipide therapy in chronic gastritis patients with refractory dyspeptic symptoms, we enrolled 30 patients with chronic gastritis nonresponsive to the antisecretory medications, proton pump inhibitors. Upper gastrointestinal endoscopy was performed in all patients to confirm and evaluate the severity of gastritis by gastric mucosal injury score and the histology by the updated Sydney system before and after treatment with rebamipide 300 mg daily for 8 weeks. At the end of the study, significant improvement in the scores for symptoms (epigastralgia, stomach heaviness, and abdominal fullness) and endoscopic mucosal injury were observed for all patients. The degrees of neutrophil activity in antrum and mononuclear cell inflammation in both body and antrum significantly decreased from baseline. Improvement of gastritis might be the mechanism by which rebamipide prevents gastric mucosal inflammation. In conclusion, rebamipide treatment improved symptom, endoscopic, and histologic features of chronic gastritis in patients with refractory dyspeptic symptoms.

Relationship between diseases accompanied by tissue destruction and granulocytes with surface adrenergic receptors

It is well-known that physiological phenomena and certain diseases, including neonatal granulocytosis, age-associated granulocytosis, periodontitis, pancreatitis, Crohn's disease, ulcerative colitis, hemorrhoids, endometriosis, and NSADs-enteritis, are accompanied by tissue destruction and granulocytosis. We investigated what is a key factor connecting tissue destruction and granulocytosis, attention being focused on adrenergic receptors on granulocytes and stress-induced sympathetic nerve stimulation. If we introduce the concept that "granulocytosis and subsequent tissue destruction are induced by sympathetic nerve stimulation," the mechanisms underlying many physiological phenomena and the etiology of several uncurable diseases in humans can be clearly understood.

Overview: Helicobacter pylori and extragastric disease

Isolation of the gastric spiral bacterium Helicobacter pylori totally reversed the false dogma that the stomach was sterile. In addition to its causal role in peptic ulceration, the newly identified bacterium has now been implicated in other gastric and even extragastric diseases, including chronic atrophic gastritis, gastric MALT lymphoma, gastric cancer, functional dyspepsia, idiopathic thrombocytopenic purpura (ITP), iron deficiency anemia, chronic urticaria, ischemic heart disease, and others. The majority of the reports are anecdotal, epidemiologic, or eradication studies, but there are also relevant in vitro studies. ITP represents one disease showing a strong link with H pylori infection. There are also accumulating data on the role of H pylori infection in iron deficiency anemia and ischemic heart disease. In summary, the association between H pylori infection and other extragut diseases is still controversial but worthy of further investigation.

Rebamipide enema therapy as a treatment for patients with active distal ulcerative colitis

BACKGROUND

The clinical efficacy of corticosteroids in the treatment of ulcerative colitis (UC) is well-established. However, prolonged usage of these drugs can result in serious complications. Rebamipide {2-(4-chlorobenzoylamino)-3[2-(1H)-quinolinon-4-yl] propionic acid}, a cytoprotective agent, has been reported to have anti-inflammatory activity and to repair mucosal injury in animal colitis models. The aim of the present study was to assess the clinical efficacy and safety of a novel Rebamipide enema therapy in UC patients.

METHODS

Twenty patients with the active distal type of UC in whom corticosteroid treatment had been unsuccessful were treated with rectal administration of Rebamipide twice a day for 3 weeks, during which corticosteroid dosage was kept constant. The efficacy of treatment was assessed from clinical symptoms and endoscopic findings. The anti-inflammatory effect of Rebamipide was also examined by monitoring changes in the intensity of histological inflammation and levels of cytokine activity in the rectal mucosa.

RESULTS

At 3 weeks after the initiation of Rebamipide enema therapy, 11 patients (55%) achieved clinical remission. Sixteen (80%) were colonoscopically judged to be responders, with decreased levels of interleukin (IL)-1beta but not of IL-8, and an increased ratio of IL-1 receptor antagonist/IL-1beta in organ cultures of mucosal tissues. The change in the number of infiltrating neutrophils was not significantly correlated with the clinical response to this therapy. No side-effects were noted in any patients.

CONCLUSION

Rebamipide enema therapy proved to be safe and useful in corticosteroid-refractory patients with the active distal type of UC.

Effect of a gastro-protective agent, rebamipide, on symptom improvement in patients with functional dyspepsia: a double-blind placebo-controlled study in Japan

BACKGROUND AND AIM

Although mucosal protective agents have been used frequently for treatment of symptomatic gastritis, there has been no well-controlled study of functional dyspepsia. The aim of this study was to assess the efficacy of a 4-week treatment with rebamipide for the relief of overall dyspeptic symptoms and the improvement in quality of life from an untreated baseline in Japanese patients with functional dyspepsia.

METHODS

In a double-blinded, randomized, placebo-controlled, single-center study, 81 patients with functional dyspepsia were recruited and treated with rebamipide (100 mg, t.i.d.) or placebo for 4 weeks. Symptoms were assessed at baseline and at the end of the study period by a symptom questionnaire. Quality of life was evaluated by the QPD 32.

RESULTS

Data was analyzed for symptoms from 38 patients who received rebamipide and 33 patients who received placebo treatment. Overall symptoms were significantly improved in both the rebamipide and placebo treatment groups from the untreated baseline after 4 weeks of treatment, and the mean changes in overall symptoms were not significantly different between the groups. However, the improvement in symptom score was significantly greater in the treatment arm than in the placebo arm for three items, which were bloating, belching, and pain or discomfort that was relieved after a meal. Regarding quality of life, social restriction and pain intensity were significantly improved in the rebamipide treatment group in per-protocol analysis (P = 0.048 and P = 0.031, respectively).

CONCLUSIONS

Although rebamipide was not significantly better than placebo in reducing overall symptoms by 4 weeks' treatment, it may partially improve the symptoms. It may also be beneficial in improvement of quality of life in Japanese patients with functional dyspepsia.

A pilot study to evaluate a new combination therapy for gastric ulcer: Helicobacter pylori eradication therapy followed by gastroprotective treatment with rebamipide

BACKGROUND AND AIM

Controversies remain over the need for antiulcer treatment following 1-week eradication triple therapy for Helicobacter pylori-positive peptic ulcers. The usefulness of combination therapy for gastric ulcers in Japanese patients, which consists of H. pylori eradication followed by gastroprotective therapy with rebamipide, was therefore evaluated.

METHODS

The study was conducted in 52 H. pylori-positive patients with an endoscopically-proven open gastric ulcer. All patients received 1-week triple therapy (lansoprazole, amoxicillin and clarithromycin) followed by 7-week rebamipide therapy. After completion of the combination therapy, all patients underwent evaluation of ulcer healing by endoscopy, gastric ulcer symptoms and H. pylori eradication by rapid urease test and (13)C-urea breath test.

RESULTS

The ulcer healing rates were 85.7% (36/42) at 8 weeks, 83.3% (30/36) in eradicated patients and 100% (6/6) in non-eradicated patients. The overall gastrointestinal symptom-free rate improved from 19.0% at baseline to 88.1% at 8 weeks. H. pylori was effectively eradicated in 85.7% (36/42) of patients.

CONCLUSIONS

The results suggested that the combination therapy for open gastric ulcer was safe, well-tolerated and effective. However, data from a double-blind placebo-controlled study is necessary to confirm these findings.

Rebamipide significantly inhibits indomethacin-induced mitochondrial damage, lipid peroxidation, and apoptosis in gastric epithelial RGM-1 cells

Nonsteroidal antiinflammatory drugs (NSAIDs) cause complications such as gastrointestinal injury. NSAIDs were recently reported to cause mitochondrial injury: to dissipate the mitochondrial transmembrane potential (MTP), and to induce mitochondrial permeability transition pore (PTP), which liberates cytochrome c. This enzyme generates reactive oxygen species (ROS) thereby triggers caspase cascade and cellular lipid peroxidation, resulting in cellular apoptosis. However, the mechanism of this NSAID-induced MTP's role in cellular apoptosis remains unknown. Rebamipide, an antiulcer drug, is reported to scavenge ROS and to show the protective effects on indomethacin-induced tissue peroxidations. Since cytochrome c and its generation of ROS are involved in indomethacin-induced cellular apoptosis, rebamipide may attenuate mitochondrial damage. The aim of this study was to elucidate whether indomethacin induces both the MTP decrease and cellular apoptosis, and the effect of rebamipide on these phenomena. We examined the effect of rebamipide on 1) MTP change, 2) lipid peroxidation, 3) apoptosis, and 4) caspase activation using gastric mucosal epithelial cell-line treated with indomethacin. With a specially designed fluorescence analyzing microscope system, MTP change, cellular lipid peroxidation, and cellular apoptosis were investigated with the small star, filled following fluorescent dyes, MitoRed, DPPP, and Hoechst 33,258, respectively. Indomethacin treatment decreased MTP but increased both cellular lipid peroxidation and cellular apoptosis via caspase 3 and 9 activation. Rebamipide clearly inhibited these phenomena {in vitro}. We demonstrated that fluorescent dyes such as MitoRed, DPPP, and Hoechst 33,258 are useful indicators for detecting oxidative cellular injuries in living cells. Rebamipide exerts a protective effect on mitochondrial membrane stability in gastric epithelial cells.

Gastro-protective agent rebamipide induces cyclooxygenease-2 (COX-2) in gastric epithelial cells

Cyclooxyngease-2 (COX-2) is a key enzyme in prostaglandin (PG) synthesis, and COX-2 induction plays an important role in the healing of gastric ulceration. Rebamipide is a gastro-protective agent and attenuates the activity of neutrophils. A number of reports have shown that rebamipide treatment increases PG production in the gastric mucosa {in vivo}. Although its clinical significance in ulcer healing has been demonstrated, {in vitro} evidence remains to be accumulated. Non-transformed rat gastric mucosal cells (RGM1 cells) were stimulated with rebamipide. RT-PCR and Western blot analysis revealed time and dose-dependent transcriptional and translational stimulation of COX-2. PGE(2) was also produced dose-dependently. However, marked COX-2 induction by rebamipide was transient and lasted less than 24 hr. COX-1 expression was unaltered by rebamipide. Reporter assay results confirmed the stimulation of Cox-2 promoter activity by rebamipide. In conclusion, this study provides {in vitro} evidence that rebamipide transcriptionally induces COX-2 and supports the rationale for its clinical use.