Ability of rabeprazole to prevent gastric mucosal damage from clopidogrel and low doses of aspirin depends on CYP2C19 genotype

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

An update on oral antiplatelet drug interactions with proton pump inhibitors: what are the risks?

INTRODUCTION

Aspirin and anti-P2Y12 are widely prescribed in cardiovascular patients, often in combination with proton pump inhibitors (PPIs) to limit the risk of upper gastrointestinal bleedings. The potential interaction between PPIs and antiplatelet agents has been widely discussed, but doubts remain as to whether PPIs may reduce the cardiovascular protection provided by aspirin, prasugrel, ticagrelor, and clopidogrel.

AREAS COVERED

Many pharmacokinetic (PK) and pharmacodynamic (PD) studies have confirmed the interaction, especially between PPIs and clopidogrel, but with uncertain consequences on clinical outcomes. Therefore, we aimed to summarize the evidence for the widespread combined use of oral antiplatelet drugs and PPIs, to outline the current evidence supporting or opposing drug-drug interaction, and to discuss the clinical implications of such interactions.

EXPERT OPINION

A large body of evidence describes the PK/PD interaction of antiplatelet drugs with PPIs and its potential role in increasing clinical cardiovascular adverse events, but no solid clinical data have confirmed these effects. In the light of the published studies, there seems to be no restriction on the choice of PPI with aspirin, prasugrel, and/or ticagrelor. The choice of a PPI with no (or minimal) interference with the hepatic cytochrome P450 2C19 is preferred in patients receiving clopidogrel.

Cardiovascular Compatibility of Proton Pump Inhibitors: Practice Recommendations

This manuscript aims to critically evaluate the current evidence regarding adverse cardiovascular effects associated with proton pump inhibitors (PPIs) in patients with coronary artery disease (CAD). It also provides guidance for the selection of the most appropriate PPI within the context of cardiovascular polypharmacy and emphasizes the importance of establishing consensus among clinicians on the need to prescribe PPIs with limited cytochrome P450 (CYP450) enzyme inhibition to reduce the risk of drug interactions. PPIs are among the most widely used drugs for the treatment of gastroesophageal reflux disease (GERD) and the prevention of gastrointestinal (GI) bleeding. The manuscript reports the proceedings from the first practice recommendations meeting on the cardiovascular compatibility of PPIs in an Indian setting. A panel of eight Indian experts in cardiology and gastroenterology reviewed 14 consensus statements. Available literature was searched and summarized, and after multiple rounds of review, consensus was achieved for these statements. Based on the available evidence, the consensus panel highlights that a PPI with minimal drug-drug interaction (DDI) is recommended, especially in patients requiring clopidogrel or polypharmacy. Rabeprazole appears to be a good option in cases where co-prescription is indicated, owing to its optimal acid suppression and minimal drug interaction profile.

Panax quinquefolius saponins combined with dual antiplatelet therapy enhanced platelet inhibition with alleviated gastric injury via regulating eicosanoids metabolism

BACKGROUND

Panax quinquefolius saponin (PQS) was shown beneficial against platelet adhesion and for gastroprotection. This study aimed to investigate the integrated efficacy of PQS with dual antiplatelet therapy (DAPT) on platelet aggregation, myocardial infarction (MI) expansion and gastric injury in a rat model of acute MI (AMI) and to explore the mechanism regarding arachidonic acid (AA)-derived eicosanoids metabolism.

METHODS

Wistar rats were subjected to left coronary artery occlusion to induce AMI model followed by treatment with DAPT, PQS or the combined therapy. Platelet aggregation was measured by light transmission aggregometry. Infarct size, myocardial histopathology was evaluated by TTC and H&E staining, respectively. Gastric mucosal injury was examined by scanning electron microscope (SEM). A comprehensive eicosanoids profile in plasma and gastric mucosa was characterized by liquid chromatography-mass spectrometer-based lipidomic analysis.

RESULTS

PQS+DAPT further decreased platelet aggregation, lessened infarction and attenuated cardiac injury compared with DAPT. Plasma lipidomic analysis revealed significantly increased synthesis of epoxyeicosatrienoic acid (EET) and prostaglandin (PG) I2 (potent inhibitors for platelet adhesion and aggregation) while markedly decreased thromboxane (TX) A2 (an agonist for platelet activation and thrombosis) by PQS+DAPT, relative to DAPT. DAPT induced overt gastric mucosal damage, which was attenuated by PQS co-administration. Mucosal gastroprotective PGs (PGE2, PGD2 and PGI2) were consistently increased after supplementation of PQS+DAPT.

CONCLUSIONS

Collectively, PQS+DAPT showed synergistic effect in platelet inhibition with ameliorated MI expansion partially through upregulation of AA/EET and AA/PGI2 synthesis while suppression of AA/TXA2 metabolism. PQS attenuated DAPT-induced gastric injury, which was mechanistically linked to increased mucosal PG production.

Rabeprazole Coadministration Controls Ulcer Recurrence in Patients on Low-dose Aspirin Therapy: A Multicenter Prospective Study

Objective To evaluate the efficacy and safety of rabeprazole coadministration with low-dose aspirin (LDA). Methods From 2015 to 2018, we conducted a large-scale, multicenter, prospective observational study to assess the safety and efficacy of treatment with rabeprazole (5 or 10 mg/day) in combination with LDA. Results The incidence of adverse reactions was 0.73% (11/1,513 patients), with no serious adverse reactions. We found no trend toward increases in the incidence of adverse reactions with increases in treatment duration. The cumulative recurrence rate of ulcers by Week 52 (Kaplan-Meier estimates) was 3.50% (range, 1.56-7.75%). No gastrointestinal bleeding was reported. Conclusion Rabeprazole in combination with LDA appears as safe and effective in real-world situations as in clinical trials.

Endoscopic Reflux Esophagitis and Reflux-Related Symptoms after Helicobacter pylori Eradication Therapy: Meta-Analysis

Backgrounds: The etiology of gastroesophageal reflux disease (GERD) including reflux esophagitis and non-erosive reflux disease is multifactorial and a recent meta-analysis showed no association between the development of GERD and Helicobacter pylori eradication in both Western and East-Asian populations. However, the problem remains that various inclusion criteria are used in these studies, which hinders meta-analysis. With a focus on reflux esophagitis with endoscopic mucosal injury, we meta-analysed to evaluate the association between eradication and reflux esophagitis and symptoms using a clearly defined set of inclusion criteria. Methods: We conducted a meta-analysis of studies published up until March 2020, which compared the incidence of reflux esophagitis and symptoms between patients undergoing H. pylori eradication therapy in a randomized placebo-controlled trial (Category A); between patients with successful and failed eradication (Category B); and between patients with successful vs. failed eradication, receipt of placebo, or no-treatment H. pylori-positives (Category C). Results: A total of 27 studies were included. Significant statistical effects were found for development of endoscopic reflux esophagitis [relative risk (RR): 1.46, 95% confidence interval (CI): 1.16-1.84, p = 0.01] or de novo reflux esophagitis (RR: 1.42, 95% CI: 1.01-2.00, p = 0.03) in the case group that received eradication in all studies, especially in Western populations. There was no significant difference in the incidence of symptoms after eradication between patient and control groups, regardless of category, location of population, or baseline disease. Conclusions: Eradication therapy for H pylori increases the risk of reflux esophagitis, irrespective of past history of esophagitis. In contrast, no effect was seen on reflux-related symptoms.

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.

Incidence, Risk Factors, and Clinical Effects of Recurrent Diverticular Hemorrhage: A Large Cohort Study

BACKGROUND & AIMS

Although recurrent diverticular hemorrhage is common, its incidence and risk factors have not been measured outside of small institutional cohorts. We analyzed the incidence of and risk factors for recurrent diverticular hemorrhage and whether discontinuing anticoagulation after diverticular hemorrhage is associated with ischemic stroke.

METHODS

We performed a retrospective cohort study of patients enrolled in the OptumInsight Clinformatics database from 2000 through 2016. Incidence rates for initial and recurrent diverticular hemorrhage were calculated by identifying patients who had hospitalizations with a primary discharge diagnosis consistent with diverticular hemorrhage. The hazard ratios of second diverticular hemorrhage associated with anticoagulants or platelet aggregation inhibitors were calculated using Cox proportional hazards regression adjusted for demographics, comorbidities, and medication use. The hazard ratio for ischemic stroke among patients who discontinued anticoagulation after diverticular hemorrhage was calculated similarly.

RESULTS

In the cohort analyzed, 14,925 patients had an initial diverticular hemorrhage; 1368 of these patients had a second episode. The unstandardized incidence rates of initial and second diverticular hemorrhage were 10.9 per 100,000 person-years (95% confidence interval [CI] 10.7-11.0) and 3625.6 per 100,000 person-years (95% CI 3436.0-3823.0). Platelet aggregation inhibitors were associated with second episodes of diverticular hemorrhage (hazard ratio 1.47; 95% CI 1.15-1.88), whereas all classes of anticoagulation agents were not associated. Among patients with a potential indication for stroke prophylaxis, those who discontinued anticoagulation after the diverticular hemorrhage had an increased hazard of ischemic stroke (hazard ratio 1.93; 95% CI 1.17-3.19).

CONCLUSIONS

In this retrospective cohort study, platelet aggregation inhibitors, but not anticoagulants, were associated with recurrent diverticular hemorrhage. Discontinuing anticoagulation was associated with increased hazard for ischemic stroke.

Effect of Low-Dose Aspirin on Chronic Acid Reflux Esophagitis in Rats

BACKGROUND

Clinical role of low-dose aspirin (LDA) in pathogenesis of gastroesophageal reflux disease is by far controversial. This can be attributed to the paucity of basic research detailing the mechanism of LDA-induced esophageal mucosal injury (EI) on underlying chronic acid reflux esophagitis (RE).

AIM

The aim of this study was to clarify the effect of LDA on chronic RE in rats.

METHODS

Esophagitis was induced in 8-week-old male Wistar rats by ligating the border between forestomach and glandular portion with a 2-0 silk tie and covering the duodenum with a small piece of 18-Fr Nélaton catheter. Seventy-eight chronic RE rat models were divided into five treatment groups, consisting of orally administered vehicle (controls), and aspirin doses of 2, 5, 50 or 100 mg/kg once daily for 28 days. EI was assessed by gross area of macroscopic mucosal injury, severity grade of esophagitis and microscopic depth of infiltration by inflammatory cells.

RESULTS

Area of esophagitis in animals with aspirin dose of 100 mg/kg/day showed a 36.5% increase compared with controls, although it failed to achieve statistical significance (p = 0.812). Additionally, the rate of severe EI was increased in animals with aspirin dose of 100 mg/kg/day as compared with controls (p < 0.05). The grade of severity correlated with the depth of inflammation (r _s = 0.492, p < 0.001).

CONCLUSIONS

Maximal dose aspirin (100 mg/kg/day) contributed in exacerbating preexisting EI. LDA (2 and 5 mg/kg/day), on the other hand, did not affect chronic RE in this model. LDA seems to be safe for use in patients with chronic RE.

Influence of low-dose proton pump inhibitors administered concomitantly or separately on the anti-platelet function of clopidogrel

Proton pump inhibitors (PPIs) at low doses can effectively prevent gastrointestinal bleeding due to aspirin and are widely used in Japan for gastroprotection in patients taking anti-platelet agents. We examined the influence of different PPIs at low doses administered concomitantly or separately on anti-platelet functions of clopidogrel. In 41 healthy Japanese volunteers with different CYP2C19 genotypes who took clopidogrel 75 mg in the morning alone, or with omeprazole 10 mg, esomeprazole 10 mg, lansoprazole 15 mg, or rabeprazole 10 mg, either concomitantly in the morning or separately in the evening, we measured the inhibition of platelet aggregation (IPA, %) using VerifyNow P2Y12 assay at 4 h after the last clopidogrel dose on Day 7 of each regimen. IPA by clopidogrel with rabeprazole administered at lunchtime, approximately 4 h after clopidogrel, was also measured. Mean IPAs in those concomitantly receiving omeprazole, esomeprazole, lansoprazole or rabeprazole (47.2 ± 21.1%, 43.2 ± 20.2%, 46.4 ± 18.8%, and 47.3 ± 19.2%, respectively) were significantly decreased compared with those receiving clopidogrel alone (56.0%) (all ps < 0.001). This decrease was observed when PPIs were administered separately in the evening. However, IPA by clopidogrel with rabeprazole administered at lunchtime was 51.6%, which was markedly similar to that of clopidogrel alone (p = 0.114). All tested PPIs reduce the efficacy of clopidogrel when administered concomitantly. Our preliminary data suggest that administration of rabeprazole 4 h following clopidogrel may minimize potential drug-drug interactions.

Pharmacogenomics of proton pump inhibitors

At present, proton pump inhibitors (PPIs), as a class of strong antacid agents, are widely used in the clinical treatment of gastrointestinal diseases. PPIs achieved a strong effect of acid suppression with high specificity and long duration. However, the issue of PPI abuse exists worldwide because of the lack of relevant knowledge. Due to tremendous inter-individual differences in uptake, the clinical application of PPIs appears to be limited. Therefore, rational use of PPIs in daily clinical practice is an important research topic. In addition, PPIs were found with many side effects. CYP2C19, as one of the most important enzymes in cytochrome P450 enzyme family, is responsible for the metabolism of over 10% of drugs. The bioavailability and metabolism of PPIs are mainly affected by drug-metabolizing enzymes CYP2C19 and CYP3A4, which are located in the liver. By suppressing cytochrome P450 isoenzyme, PPIs may affect the metabolism of multiple drugs, thus leading to unwanted side effects in case of combined medication. What's more, the individual difference in PPI administration is derived from distinct molecular mechanisms mediated by CYP3A4 and/or CYP2C19. Non-genetic factors, such as combined medication and food pyramid, also impact on the effectiveness of PPIs. Gene mutations can also alter the enzymatic activity of CY2C19, thereby resulting in different blood concentrations of drugs metabolized by CYP2C19. In conclusion, PPIs have the advantages of safety and effectiveness; however, the problem of drug resistance still exists, which indicates their selective application in clinical practice. In this paper, we review the advances in pharmacogenomics of PPIs, with an aim to provide reference to individualized clinical medication.

Potent Gastric Acid Inhibition Over 24 Hours by 4-Times Daily Dosing of Esomeprazole 20 mg

BACKGROUND

When administered at a standard dose, proton pump inhibitors (PPIs) do not always provide sufficient acid inhibition for all subjects, particularly in extensive metabolizers (EMs) of CYP2C19. Whether esomeprazole at a dose of 20 mg four times daily dosing (q.i.d.) can attain sufficient acid inhibition throughout 24 h in EMs remains unclear. We therefore investigated the efficacy of esomeprazole q.i.d. for acid inhibition.

METHODS

In a randomized cross-over design, 30 Helicobacter pylori-negative healthy young Japanese volunteers received esomeprazole at a dose of 20 mg two times a day (b.i.d.) or q.i.d. for 7 days. A pH monitoring was conducted before the trial as a control and on day 7 of both regimens.

RESULTS

Median pH values in the q.i.d. regimen were significantly higher than those with the b.i.d. regimen in EMs (b.i.d.: 5.3, q.i.d.: 6.6, p = 0.022), intermediate metabolizer (IM) (b.i.d.: 5.5, q.i.d.: 6.8, p = 0.005) and poor metabolizer (PM) (b.i.d.: 6.2, q.i.d.: 7.0, p = 0.047), respectively. Median pH with the b.i.d. regimen differed significantly by CYP2C19 genotypes (p = 0.004), but not the q.i.d. regimen (p = 0.384).

CONCLUSION

Esomeprazole q.i.d. achieved potent acid inhibition in all Helicobacter pylori-negative subjects, irrespective of CYP2C19 genotype, which might be one of the rescue regimens for patients' refractory to PPI treatment.

Effect of bacterial and host factors on Helicobacter pylori eradication therapy

INTRODUCTION

A clearer understanding of the factors affecting the cure rate of Helicobacter pylori infection might lead to the development of novel prevention strategies and therapeutic targets.

AREAS COVERED

This review covers two important issues that affect the eradication of H. pylori: bacterial and host factors. Several virulence factors have been shown to be predictors for gastroduodenal diseases. Successful treatment of H. pylori infection also depends on host genetic factors such as CYP2C19 and IL-1B. The latest evidence on host genetic factors is discussed.

EXPERT OPINION

The authors identify three main targets for achieving effective eradication therapy. The first therapeutic target is to identify counter measures for antibiotic-resistant H. pylori strains. Thus, antibiotic susceptibility should be checked in all patients, ideally, before the start of eradication treatment. The second therapeutic target is the inhibition of acid suppression. Maintaining a high intragastric pH for 24 h increases the effectiveness of some antibiotics and the eradication effects for H. pylori. The third therapeutic target is to identify high-risk groups; the CYP2C19 and IL-1B polymorphisms are candidates for significant risk factors. A personalized medical approach will likely increase the cure rate of H. pylori infection.

Long-term efficacy and safety of rabeprazole in patients taking low-dose aspirin with a history of peptic ulcers: a phase 2/3, randomized, parallel-group, multicenter, extension clinical trial

A 24-week, double-blind, clinical trial of rabeprazole for the prevention of recurrent peptic ulcers caused by low-dose aspirin (LDA) has been reported, but trials for longer than 24 weeks have not been reported. The aim of this study is to assess the long-term efficacy and safety of rabeprazole for preventing peptic ulcer recurrence on LDA therapy. Eligible patients had a history of peptic ulcers on long-term LDA (81 or 100 mg/day) therapy. Patients with no recurrence of peptic ulcers at the end of the 24-week double-blind phase with rabeprazole (10- or 5-mg once daily) or teprenone (50 mg three times daily) entered the extension phase. Rabeprazole doses were maintained for a maximum of 76 weeks, including the double-blind 24-week period and the extension phase period (long-term rabeprazole 10- and 5-mg groups). Teprenone was randomly switched to rabeprazole 10 or 5 mg for a maximum of 52 weeks in the extension phase (newly-initiated rabeprazole 10- and 5-mg groups). The full analysis set consisted of 151 and 150 subjects in the long-term rabeprazole 10- and 5-mg groups, respectively, and the cumulative recurrence rates of peptic ulcers were 2.2 and 3.7%, respectively. Recurrent peptic ulcers were not observed in the newly-initiated rabeprazole 10- and 5-mg groups. No bleeding ulcers were reported. No clinically significant safety findings, including cardiovascular events, emerged. The use of long-term rabeprazole 10- and 5-mg once daily prevents the recurrence of peptic ulcers in subjects on low-dose aspirin therapy, and both were well-tolerated.

Recurrence and mortality among patients hospitalized for acute lower gastrointestinal bleeding

BACKGROUND & AIMS

The long-term recurrence of lower gastrointestinal bleeding (LGIB) and associated mortality have not been studied extensively. We investigated rates of recurrence of LGIB, mortality, and associated risk factors.

METHODS

In a retrospective study, we analyzed data from 342 patients hospitalized for overt LGIB at the National Center for Global Health and Medicine in Japan from December 2004 through June 2013. All patients underwent colonoscopy. We assessed Charlson comorbidity index scores and the use of nonsteroidal anti-inflammatory drugs, low-dose aspirin, other antiplatelet drugs, or warfarin. Rebleeding, the total number of rebleeding episodes, and mortality were measured. The Cox proportional hazards model was used to estimate hazard ratios (HRs).

RESULTS

Rebleeding occurred in 84 patients, at a mean follow-up time of 19 months. The cumulative percentages of patients with rebleeding at 1 and 5 years were 19% and 46%, respectively. During the follow-up period, 29 patients (39%) had secondary rebleeding and 18 patients (62%) had subsequent rebleeding. Multivariate analysis showed age 65 years and older (HR, 1.7; P = .04) and the use of nonsteroidal anti-inflammatory drugs (HR, 2.0; P < .01) and nonaspirin antiplatelet drugs (HR, 1.8; P < .05) as independent risk factors for rebleeding. Dual therapy had a higher risk than single therapy (adjusted HR, 1.8; P < .05). During the mean follow-up period of 28 months, 21 patients died (2 from bleeding). Cumulative mortality rates at 1 and 5 years were 4.2% and 13%, respectively. Mortality was associated significantly with age ≥65 years (P < .05), Charlson comorbidity index score, and warfarin use.

CONCLUSIONS

Based on a retrospective analysis of patients with LGIB, 46% of all patients have rebleeding, and the overall mortality rate is 13% within 5 years after hospitalization. Besides age ≥65 years, use of antithrombotic drugs increases the risk of bleeding recurrence and mortality among patients with LGIB.

Randomised clinical trial: prevention of recurrence of peptic ulcers by rabeprazole in patients taking low-dose aspirin

BACKGROUND

Few studies have evaluated the effects of rabeprazole on low-dose aspirin (LDA)-induced gastroduodenal injuries.

AIM

To conduct a randomised, double-blind, triple-dummy, active-controlled, multicentre trial, named the PLANETARIUM study, to assess the efficacy, dose-response relationship and safety of rabeprazole for peptic ulcer recurrence in Japanese patients on long-term LDA therapy.

METHODS

Eligible patients had a history of endoscopically confirmed peptic ulcers and were receiving long-term LDA (81 or 100 mg/day) therapy for cardiovascular or cerebrovascular protection. Subjects were randomly segregated into three groups receiving rabeprazole 10 mg once daily (standard dose in Japan), rabeprazole 5 mg once daily, or teprenone (geranylgeranylacetone; mucosal protective agent commercially available in Japan) 50 mg three times per day as an active control. The primary endpoint was recurrence of peptic ulcers over 24 weeks.

RESULTS

Among 472 randomised subjects, 452 subjects (n = 151, 150, 151, respectively) constituted the full analysis set. The cumulative recurrence rates of peptic ulcers over 24 weeks in the 10- and 5-mg rabeprazole groups were 1.4% and 2.8%, respectively, both of which were significantly lower than that in the teprenone group (21.7%). The cumulative occurrence rate of bleeding ulcers over 24 weeks in the teprenone group was 4.6%, while bleeding ulcers were not observed in the 10- or 5-mg rabeprazole groups. Rabeprazole was well tolerated at both doses.

CONCLUSION

Rabeprazole prevents the recurrence of peptic ulcers with no evidence of a major dose-response effect in subjects on low-dose aspirin therapy.

A randomized, double-blind, placebo-controlled study of rebamipide for gastric mucosal injury taking aspirin with or without clopidogrel

INTRODUCTION

Antithrombotic drugs, such as low-dose aspirin (LDA) and clopidogrel, can cause upper gastrointestinal complications.

AIM

The goal of the present study was to investigate whether a mucosal-protective agent, rebamipide, could prevent gastric mucosal injuries induced by LDA with or without clopidogrel in healthy subjects.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled trial was performed with 32 healthy male volunteers. Subjects were randomly assigned to a 14-day course of one of the following regimens: group A, placebo (tid) + LDA; group B, rebamipide (100 mg tid) + LDA (100 mg once-daily); group C, placebo + LDA + clopidogrel (75 mg once-daily); or group D, rebamipide + LDA + clopidogrel. The grade of gastric mucosal injuries was evaluated by esophagogastroduodenoscopy before and after dosing (on day 0 and day 14), and the grade of gastric mucosal injury was assessed according to the modified Lanza score. Subjective symptoms were assessed using the Gastrointestinal Symptom Rating Scale (GSRS). A rapid urease test was performed on day 0, and blood tests were performed on day 0 and day 14.

RESULTS

Rebamipide significantly inhibited gastric mucosal injury induced by LDA alone or by LDA plus clopidogrel when compared with placebo in healthy subjects. GSRS score and hemoglobin level were not significantly different among the four groups.

CONCLUSIONS

Rebamipide is useful for the primary prevention of gastric mucosal injury induced by LDA alone or by LDA plus clopidogrel in healthy subjects.

Comparison of acid inhibition with standard dosages of proton pump inhibitors in relation to CYP2C19 genotype in Japanese

INTRODUCTION

The aim of therapeutic regimens using proton pump inhibitors (PPIs) in patients with acid-related diseases is to potently inhibit acid secretion for the full 24 h. However, optimum treatment is still unclear because the pharmacodynamics of PPIs differ among CYP2C19 genotypes and most of the previous studies have had loss of sample power.

METHODS

Using pH monitoring, we compared acid inhibition at standard dosage of omeprazole (20 mg, 50 times), lansoprazole (30 mg, 68 times), and rabeprazole (10 mg, 65 times) in Helicobacter pylori-negative healthy young Japanese volunteers.

RESULTS

Median pH with rabeprazole was 5.4 (3.3-7.5), which was significantly greater than with either omeprazole [4.4 (2.1-7.3)] or lansoprazole [4.8 (3.5-6.4)] (both P < 0.05). Median 24-h pH differed among the different CYP2C19 genotypes in all three PPIs. In CYP2C19 extensive metabolizers (EMs), the genotype that is refractory to PPI treatment, median pH with omeprazole, lansoprazole, and rabeprazole was 3.8 (2.1-4.4), 4.5 (3.5-5.3) and 4.8 (3.3-7.5), respectively.

DISCUSSION

Treatment with the selected PPIs at their standard dosages had difficulty maintaining acid inhibition for a full 24 h, especially in CYP2C19 EM. However, rabeprazole has the merit of less influence of CYP2C19 genotype compared with the other PPIs.

Clinical significance of Helicobacter pylori infection in patients with acute coronary syndromes: an overview of current evidence

Although Helicobacter pylori (Hp) primarily colonizes gastric mucosa, it can occasionally inhabit in atherosclerotic plaques. Both forms of Hp infection may be involved in the pathogenesis of atherosclerosis via activation of a systemic or local inflammatory host reaction and induction of plaque progression and/or instability, possibly leading to coronary syndromes. The association between Hp infection and cardiovascular endpoint prevalence remains uncertain; however, it has been reported in many epidemiological investigations and may be reasonably explained by pathophysiological mechanisms. Besides the inflammatory pathway, Hp infection may trigger acute coronary syndromes by enhanced platelet reactivity and increased risk of gastrointestinal bleeding (type 2 myocardial infarction). The former seems to be predominantly related to the stimulatory effect of Hp infection on von Willebrand factor-binding and P-selectin activation, and the latter results from cytotoxic bacteria properties and aggravation of digestive tract injury related to aspirin or dual antiplatelet therapy. Despite these premises, the role of Hp infection in cardiovascular syndromes should still be recognized as controversial and requiring randomized, controlled trials to evaluate the outcome of Hp eradication in both cardiac and gastroenterological endpoints. Such need is also justified by potential bias of previous studies resulting from (1) using different diagnostic methods for identification of Hp infection, since only a small number of studies required confirmation of active Hp infection; and from (2) common lack of adjustment for important confounders such as socioeconomic status, smoking and effectiveness of eradication therapy, as well as the genetic characteristics of both the host and the bacterium.

Attenuated expression of the tight junction proteins is involved in clopidogrel-induced gastric injury through p38 MAPK activation

Bleeding complications and delayed healing of gastric ulcer associated with use of clopidogrel is a common clinical concern; however, the underlying mechanisms remain to be determined. This study aimed to clarify whether clopidogrel could cause the damage of the human gastric epithelial cells and to further elucidate the mechanisms involved. After human gastric epithelial cell line GES-1 had been treated with clopidogrel (0.5-2.5 mM), the cell proliferation was examined by MTT assay, apoptosis was measured with DAPI staining and flow cytometry analysis, and the barrier function of the tight junctions (TJ) was evaluated by permeability measurement and transmission electron microscopy. Moreover, expression of the TJ proteins occludin and ZO-1 and the phosphorylation of the mitogen-activated protein kinases (MAPK) p38, ERK, and JNK were examined by western blot. In addition, three MAPK inhibitors specific to p38, ERK and JNK were used, respectively, to verify the signaling pathways responsible for regulating the expression of the TJ proteins being tested. Results showed that clopidogrel significantly increased dextran permeability, induced apoptosis, suppressed GES-1 cell viability, and reduced the expression of the TJ proteins (occludin and ZO-1), acting through p38 MAPK phosphorylation. Furthermore, these observed effects were partially abolished by SB-203580 (a p38 MAPK inhibitor), rather than by either U-0126 (an ERK inhibitor) or SP-600125 (a JNK inhibitor), suggesting that clopidogrel-induced disruption in the gastric epithelial cells is mediated by the p38 MAPK pathway. It is concluded that attenuated expression of the TJ proteins occludin and ZO-1 in human gastric epithelial cells could be involved in clopidogrel-induced gastric mucosal injury through activation of the p38 MAPK pathway.