Omeprazole attenuates oxygen-derived free radical production from human neutrophils

Omeprazole treatment manifests anxiolytic effects in a cysteamine hydrochloride induced mouse model of gastrointestinal disorder

Omeprazole, a proton pump inhibitor (PPI), has widely been used to treat various gastrointestinal (GI) disorders. Notably, many clinical symptoms of GI disorders have been known to be associated with anxiety. In recent years, an exponentially increased number of subjects with abnormal ageing, neurological deficits, and psychiatric problems simultaneously exhibit GI dysfunctions as well as anxiety. Considering the fact, drugs that are used to treat GI disorders can be speculated to mitigate anxiety-related symptoms, and vice versa. Although, omeprazole treatment has been reported to result in development of anxiety and neurocognitive decline, ample reports suggest that omeprazole treatment is beneficial for the positive regulation of neuroplasticity. While underlying mechanisms of omeprazole-mediated neurological alterations remain obscure, the available scientific data on the omeprazole induced adverse effects in the brain appear to be inadequate, uncertain, and controversial. Hence, this study revisited the effect of omeprazole treatment on the degree of anxiety-like behaviours in a cysteamine hydrochloride (HCl) induced mouse model of GI disorder using open field test (OFT), light-dark box (LDB) test and elevated plus maze (EPM). Results revealed that omeprazole treatment mitigates anxiety-related behaviours in the cysteamine HCl induced animal model of GI disorder. Thus, this study assuredly supports and validates the anxiolytic properties of omeprazole. However, the adverse effects associated with inappropriate intake of omeprazole may not completely be excluded. Therefore, this study advocates the future direction in determining the long-term effects of omeprazole on the brain functions.

Association between Proton Pump Inhibitor Use and Parkinson's Disease in a Korean Population

Few studies have shown an increased risk of Parkinson’s disease (PD) with the use of proton pump inhibitors (PPIs), and the pathophysiological mechanism for this association has not been unveiled. This study examined the relationship between PPI use and PD in a Korean population. We investigated 3026 PD patients and 12,104 controls who were matched by age, sex, income, and region of residence at a ratio of 1:4 in the Korean National Health Insurance Service, National Sample Cohort between 2002 and 2015. We estimated the associations between current and past use of PPIs and PD using odds ratios (ORs) and 95% confidence intervals (CIs) in a conditional/unconditional logistic regression after adjusting for probable confounders. Compared with PPI nonusers, both current users and past users had significantly greater odds of having PD, with ORs of 1.63 (95% CI = 1.44−1.84) and 1.12 (95% CI = 1.01−1.25), respectively. A significant association with PD was observed in individuals who used PPIs for 30−90 days and ≥90 days (OR = 1.26 and 1.64, 95% CI = 1.12−1.43 and 1.43−1.89) but not among those who used PPIs for <30 days. Both current and past use of PPIs associated with a higher probability of PD in the Korean population. Our study provides evidence regarding the association between PPI exposure and PD, but further investigation and possible explanations are warranted.

A case of eosinophilic gastroenteritis with high PET-CT accumulation treated by P-CAB

Eosinophilic gastroenteritis (EGE) can present findings on computed tomography (CT) images that resemble malignant tumors. EGE is generally treated with systemic oral steroid administration, which is reportedly effective in relieving symptoms at least temporarily. Here, we report a case of EGE that mimicked malignant lymphoma in a gastroduodenal lesion, in which treatment with a potassium-competitive acid blocker without systemic oral steroid administration relieved the symptoms and reversed the initial image findings. A 56-year-old woman became aware of discomfort in her epigastric region, which gradually worsened. This case showed antroduodenal wall thickness, which mimicked a malignant lymphoma with increased F-18 fluorodeoxyglucose (FDG) uptake by positron emission tomography/computed tomography (PET/CT). An upper gastrointestinal endoscopy revealed protruding erosions in the antrum and severe edematous changes in the duodenum. Extensibility of the normal gastric wall by insufflation also occurred. However, an abdominal ultrasound indicated wall thickening with a preserved wall structure. Histological examinations showed a large amount of eosinophil infiltration, mainly in the gastroduodenal mucosa, without malignant cells. Thus, we made a final diagnosis of EGE. The patient was then administered 20 mg vonoprazan fumarate per day because she refused steroid treatment and because the pathological lesion was also localized from the duodenum to the antrum. After 3 weeks of potassium-competitive acid blocker treatment, her symptoms were alleviated, and the degree and extent of thickening of the gastroduodenal wall in upper gastrointestinal endoscopy and ultrasonographic image findings had remarkably improved.

Vonoprazan shows efficacy similar to that of proton pump inhibitors with respect to symptomatic, endoscopic, and histological responses in patients with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic allergic disease with esophageal symptoms and intraepithelial eosinophil infiltration. Effects of potassium-competitive acid blockers (P-CABs) on EoE have not been elucidated. We aimed to examine and compare the effects of P-CABs and PPIs on symptomatic, endoscopic, and histological responses of patients with EoE.

METHODS

We analyzed 118 EoE patients who received PPI or P-CAB therapy with rabeprazole 10 mg (RPZ10, N = 22), rabeprazole 20 mg (RPZ20, N = 34), esomeprazole 20 mg (EPZ20, N = 25), or vonoprazan 20 mg (VPZ20, N = 33). We evaluated symptomatic responses by classifying the patients into three groups: complete relief, partial relief, and no change. Endoscopic responses were evaluated using the endoscopic reference score (EREFS) following PPI or P-CAB therapy. Histological responses were evaluated by determining eosinophil counts in esophageal biopsy samples and classifying the patients into two groups: complete remission [0/1 eosinophil/high-power field (eos/HPF)] and remission (< 15 eos/HPF).

RESULTS

There were no differences among the therapy groups in terms of clinical characteristics, endoscopic findings, and histological findings of the patients before treatment. The rate of complete relief in clinical symptoms was 54.5% in the RPZ10 group, 64.7% in the RPZ20 group, 72.0% in the EPZ20 group, and 75.7% in the VPZ20 group. There were no significant differences in the therapeutic effect among the therapy groups. Similarly, endoscopic and histological complete remission rates were not significantly different among the therapy groups.

CONCLUSIONS

Vonoprazan showed similar efficacy to PPIs in EoE.

Possible Effects of Proton Pump Inhibitors on Hearing Loss Development

Considered safe and often available as over-the-counter (OTC) drugs, proton pump inhibitors (PPI) are one of the most frequently used medicines. Over recent years much research analyzing PPI has been conducted and these studies shed light on PPI side effects and the mechanisms of these processes. In this study we summarize the findings of these studies and through deduction present some hypotheses on the impact of PPI on health. Of particular interest is the impact of PPI on hearing loss development. However, despite this side effect being localized, its mechanisms are complex, systemic and involve changes in whole body. This paper summarizes how through, inter alia, alterations in the circulatory system, respiratory system, central nervous system and metabolism PPI can cause hearing impairment, which can occur in every age group and is connected with long-term use of this group of drugs. This article also discusses the role PPI plays in the acceleration of presbycusis development, in relation to the fact that older people are the group who most frequently use PPI in long term. Hearing loss negatively impacts affects quality of life, especially among older patients who are also the most afflicted group; administration of PPI should therefore be considered carefully, taking into consideration all potential benefits and side effects.

Protective Effect of Kolaviron on Cyclophosphamide-Induced Cardiac Toxicity in Rats

BACKGROUND

Cyclophosphamide (CP) is a nitrogen mustard alkylating drug used for the treatment of chronic and acute malignant lymphomas, myeloma, leukemia, neuroblastoma, adenocarcinoma, retinoblastoma, breast carcinoma, and immunosuppressive therapy. Despite its vast therapeutic uses, it is known to cause severe cardiac toxicity. Kolaviron (KV), a Garcinia kola seed extract containing a mixture of flavonoids, is reputed for its antioxidant and membrane stabilizing properties.

OBJECTIVE

This study investigated the protective effect of KV on CP-induced cardiotoxicity in rats.

METHODS

Thirty rats were used, and they were divided into 6 groups of 5 rats each. Group I received 2 mL/kg propylene glycol orally for 14 days; group II received CP (50 mg/kg/d, intraperitoneally [i.p.]) for 3 days; groups III and IV received 200 and 400 mg/kg/d KV, respectively, orally for 14 days and groups V and VI were pretreated with 200 and 400 mg/kg/d KV, respectively, orally for 14 days followed by CP (50 mg/kg/d, i.p.) for 3 days.

RESULTS

CP treatment resulted in a significantly lower food consumption and body weight in rats. The lactate dehydrogenase and creatine kinase enzymes in cardiac tissues of rats treated with CP were significantly higher. In cardiac tissues, 3-day doses of CP resulted in significantly higher heart weight, cardiac troponin I, myeloperoxidase, malondialdehyde, hydrogen peroxide and lower superoxide dismutase, catalase, glutathione peroxidase activities, and reduced glutathione levels. Histological examination of cardiac tissues showed sign of necrosis of myocardium after CP treatment. However, administration of KV at 200 and 400 mg/kg for 14 days prior to CP treatment, increase food consumption, body weight, and attenuates the biochemical and histological changes induced by CP.

CONCLUSIONS

These results revealed that KV attenuates CP-induced cardiotoxicity by inhibiting oxidative stress and preserving the activity of antioxidant enzymes.

Proton Pump Inhibitors: What the Internist Needs to Know

This report reviews the physiology of gastric acid suppression by proton pump inhibitors (PPIs) and anti-inflammatory effects of PPIs that are independent of their acid-suppressive effects. Valid indications for PPI use are discussed, as are putative adverse effects of PPIs that have been identified through weak associations in observational studies that cannot establish cause-and-effect relationships. Although evidence supporting the validity of these adverse effects is weak, there is also insufficient evidence to dismiss the risks. The report emphasizes how PPIs frequently are prescribed inappropriately and encourages physicians to carefully consider the indication for PPI therapy in their patients.

Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the AGREE Conference

BACKGROUND & AIMS

Over the last decade, clinical experiences and research studies raised concerns regarding use of proton pump inhibitors (PPIs) as part of the diagnostic strategy for eosinophilic esophagitis (EoE). We aimed to clarify the use of PPIs in the evaluation and treatment of children and adults with suspected EoE to develop updated international consensus criteria for EoE diagnosis.

METHODS

A consensus conference was convened to address the issue of PPI use for esophageal eosinophilia using a process consistent with standards described in the Appraisal of Guidelines for Research and Evaluation II. Pediatric and adult physicians and researchers from gastroenterology, allergy, and pathology subspecialties representing 14 countries used online communications, teleconferences, and a face-to-face meeting to review the literature and clinical experiences.

RESULTS

Substantial evidence documented that PPIs reduce esophageal eosinophilia in children, adolescents, and adults, with several mechanisms potentially explaining the treatment effect. Based on these findings, an updated diagnostic algorithm for EoE was developed, with removal of the PPI trial requirement.

CONCLUSIONS

EoE should be diagnosed when there are symptoms of esophageal dysfunction and at least 15 eosinophils per high-power field (or approximately 60 eosinophils per mm²) on esophageal biopsy and after a comprehensive assessment of non-EoE disorders that could cause or potentially contribute to esophageal eosinophilia. The evidence suggests that PPIs are better classified as a treatment for esophageal eosinophilia that may be due to EoE than as a diagnostic criterion, and we have developed updated consensus criteria for EoE that reflect this change.

Proton Pump Inhibitors in IPF: A Call for Clinical Trials

The recent FDA approval of two drugs, pirfenidone and nintedanib, for the treatment of idiopathic pulmonary fibrosis (IPF) has fueled interest in the development of additional drugs to treat the disease or its major clinical complications including cough and acute exacerbations. Since 2015, there are at least a dozen active interventional studies that are testing the efficacy of novel pharmacotherapies, exercise or stem cells in modifying the disease process in IPF. Additionally, there are combinatorial studies evaluating the effectiveness of pirfenidone or nintedanib in combination with other agents. However, there remains an urgent need for clinical trials to prospectively evaluate the efficacy of existing drugs with promising retrospective data, such as proton pump inhibitors (PPIs), in IPF. Several retrospective cohorts have provided tantalizing data supporting the beneficial effect of PPIs in patients with well-defined IPF. This review provides the general outlook of pharmacotherapies in IPF, and highlights preclinical and retrospective clinical data to make a case for randomized controlled clinical trials of PPIs in IPF.

Combined but not single administration of vitamin C and l-carnitine ameliorates cisplatin-induced gastric mucosa damage in male rats

Although cisplatin is a potent anticancer drug, it instigates oxidative and pro-inflammatory reactions that pose significant and distressing clinical symptoms. Therefore, this study investigated the effects of vitamin C and (or) l-carnitine on cisplatin-induced gastric mucosa damage in rat. The rats were allocated into 6 groups (n = 5). The control group received distilled water, while the treatment groups received cisplatin alone (CIP), or cisplatin with vitamin C, l-carnitine, or their combination. Cisplatin caused disruption of the gastric mucosa histoarchitecture and altered the mucus barrier function. Moreover, the stomach tissue of the CIP-treated group showed increased levels of oxidative stress markers (malondialdehyde and H₂O₂) and decreased activities of antioxidant (superoxide dismutase, glutathione peroxidase, catalase, glutathione S-transferase) and non-antioxidant (reduced glutathione) enzymes. These deleterious events were accompanied with significant increases in pro-inflammatory cytokines and inflammatory infiltration markers, myeloperoxidase and inducible nitric oxide synthase. However, the administration of both vitamin C and l-carnitine, and not either of the two showed additive effects in attenuating the adverse effects of cisplatin. The histological results agreed with the biochemical assays. The study concluded that the combined administration of vitamin C and l-carnitine, but not the single therapy, could prevent the adverse effects of cisplatin on gastric tissue.

Proton-pump inhibitors elevate infection rate in cardiothoracic surgery patients by influencing PMN function in vitro and in vivo

Proton-pump inhibitors (PPI) as pantoprazole are highly effective acid suppressive agents that belong to the world's most sold medication. However, they are pronounced to have immunosuppressive aspects. In our study, a negative influence of PPI on functions of polymorphonuclear cells in vitro like phagocytosis, oxidative burst, chemotaxis, and killing activity was shown, whereas formation of neutrophil extracellular traps (NET)osis remained unaffected. Pantoprazole stimulation additionally reduced the production of the proinflammatory cytokine IL-1β in whole blood assay as well as the production of IL-2 and IFN-γ after whole blood stimulation with phytohaemagglutinin. Moreover, IFN-γ feedback mechanisms and signaling by STAT-1 was impaired by PPI. Cardiac surgery is accompanied by developing systemic inflammatory response syndrome with immunosuppressive aspects. We exhibited reduced oxidative burst analyzing cardiac surgery patients' samples receiving or not receiving PPI. Furthermore, a higher rate of infections in patients receiving permanent PPI medication in retrospective analysis was uncovered. Patients undergoing cardiac surgery with cardiopulmonary bypass and regular PPI medication developed significant more infections retrospectively indicating a clinical impact of the immunosuppressive influence of PPI.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

The effect of omeprazole treatment on the gut microflora and neutrophil function

BACKGROUND AND AIM

Proton pump inhibitors (PPIs) may increase the risk of Clostridium difficile infections. There are interactions between gut microbiota and innate immune cells including neutrophils. We evaluated the effect of treatment with omeprazole on the gut microflora and neutrophil function.

METHODS

In 50 patients, we evaluated the effect of 4-week omeprazole treatment (n=25 with 20mg per day and n=25 with 20mg twice daily) on intragastric pH, results of stool culture and lactulose hydrogen breath test (LHBT) and neutrophil function.

RESULTS

The treatment caused significant increase of the mean intragastric pH, especially in the group with 20mg omeprazole twice daily (from 2.05±0.59 to 5.06±1.6, P<0.001). In LHBT, the increase of hydrogen concentration was observed in higher percentage of patients with 20mg of omeprazole twice daily, compared to patients with the lower dose (42.1% vs 29.4%; ns). Four weeks of omeprazole treatment have caused considerable changes in stool culture results. Patients treated with higher dose of omeprazole have had some tendency to decrease diversity of colonic microflora in comparison with patients treated with the lower dose of omeprazole. Treatment with omeprazole did not result in C. difficile positive stool culture and had no significant effect on neutrophil function.

CONCLUSIONS

Omeprazole treatment have caused considerable changes in stool culture results. Patients treated with the higher dose had some tendency to decreased diversity of colonic microflora and towards changes in fermenting bacteria of the gut. The potential effect of omeprazole on gut microflora does not depend on neutrophil function deterioration.

The effect of short-term oral treatment with omeprazole or pantoprazole on the function of polymorphonuclear neutrophils

Recent studies report an increased risk of enteric infections in patients treated with proton pump inhibitors (PPIs). Polymorphonuclear neutrophils (PMNs) play a key role in host response to bacterial infection. We evaluated the effect of omeprazole and pantoprazole treatment on the PMN function. Fifteen patients were treated with omeprazole 20 mg daily and 15 patients with pantoprazole 40 mg daily for 7 days. Treatment with omeprazole or pantoprazole had no effect on spontaneous nitroblue tetrazolium (NBT) test results. Significant increase in the percentage of phagocytes in the omeprazole group in stimulated NBT test (by 69%) was found. Treatment with omeprazole or pantoprazole had no effect on nitric oxide (NO) concentration in the PMN culture supernatant and serum, cyclic guanosine monophosphate concentration in the PMN culture supernatant and serum, as well as inducible nitric oxide synthase (iNOS) protein expression and p38 mitogen-activated protein kinase activity in PMNs. In conclusion, treatment with PPI has no effect on NO production and p38 mitogen-activated protein kinase activity in PMNs. Interestingly, short-term treatment with omeprazole but not with pantoprazole enhances PMN reactive oxygen species production.

Oxidative Stress and Hypertensive Diseases

It has become clear that reactive oxygen species (ROS) contribute to the development of hypertension via myriad effects. ROS are essential for normal cell function; however, they mediate pathologic changes in the brain, the kidney, and blood vessels that contribute to the genesis of chronic hypertension. There is also emerging evidence that ROS contribute to immune activation in hypertension. This article discusses these events and how they coordinate to contribute to hypertension and its consequent end-organ damage.

Omeprazole Induces Apoptosis in Jurkat Cells

We report for the first time a potent apoptotic effect of omeprazole (OM). Apoptosis was induced in Jurkat cells in a time and concentration-dependent mode. Caspase 3 and PARP were rapidly cleaved in response to OM, but apoptosis was only partially inhibited by the caspase 3 inhibitor DEVD-CHO. OM also induced an early lysosomal destabilization which increased progressively and was correlated with a parallel increase in apoptotic cells. The cysteine protease inhibitor E64d gave strong protection against apoptosis thus proving the involvement of lysosomal enzymes in OM-induced apoptosis whereas, it did not impede the caspase 3 cleavage. Instead ZVAD-fmk, a general caspase inhibitor, also able to inhibit cathepsin activity, protected cells completely from OM-induced apoptosis. It therefore seems that both caspases and cysteine cathepsins are involved in the execution stage of OM-induced apoptosis.

Pleiotropic effect of the proton pump inhibitor esomeprazole leading to suppression of lung inflammation and fibrosis

Background

The beneficial outcome associated with the use of proton pump inhibitors (PPIs) in idiopathic pulmonary fibrosis (IPF) has been reported in retrospective studies. To date, no prospective study has been conducted to confirm these outcomes. In addition, the potential mechanism by which PPIs improve measures of lung function and/or transplant-free survival in IPF has not been elucidated.

Methods

Here, we used biochemical, cell biological and preclinical studies to evaluate regulation of markers associated with inflammation and fibrosis. In our in vitro studies, we exposed primary lung fibroblasts, epithelial and endothelial cells to ionizing radiation or bleomycin; stimuli typically used to induce inflammation and fibrosis. In addition, we cultured lung fibroblasts from IPF patients and studied the effect of esomeprazole on collagen release. Our preclinical study tested efficacy of esomeprazole in a rat model of bleomycin-induced lung injury. Furthermore, we performed retrospective analysis of interstitial lung disease (ILD) databases to examine the effect of PPIs on transplant-free survival.

Results

The cell culture studies revealed that esomeprazole controls inflammation by suppressing the expression of pro-inflammatory molecules including vascular cell adhesion molecule-1, inducible nitric oxide synthase, tumor necrosis factor-alpha (TNF-α) and interleukins (IL-1β and IL-6). The antioxidant effect is associated with strong induction of the stress-inducible cytoprotective protein heme oxygenase-1 (HO1) and the antifibrotic effect is associated with potent inhibition of fibroblast proliferation as well as downregulation of profibrotic proteins including receptors for transforming growth factor β (TGFβ), fibronectin and matrix metalloproteinases (MMPs). Furthermore, esomeprazole showed robust effect in mitigating the inflammatory and fibrotic responses in a murine model of acute lung injury. Finally, retrospective analysis of two ILD databases was performed to assess the effect of PPIs on transplant-free survival in IPF patients. Intriguingly, this data demonstrated that IPF patients on PPIs had prolonged survival over controls (median survival of 3.4 vs 2 years).

Conclusions

Overall, these data indicate the possibility that PPIs may have protective function in IPF by directly modulating the disease process and suggest that they may have other clinical utility in the treatment of extra-intestinal diseases characterized by inflammatory and/or fibrotic phases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0614-x) contains supplementary material, which is available to authorized users.

The preventive effect of β3 adrenoceptor stimulation against experimentally induced reflux esophagitis

A β3 adrenoceptor agonist plays an important regulatory role in stimulation of thermogenesis and lipolysis and it appears to have anti-ulcer and spasmolytic effects. So the present aim was to examine the effect of BRL 37344 (a selective B3 adrenoceptor agonist) on reflux esophagitis.

METHODS

Forty-eight rats were divided into twelve sham-operated with BRL 37344 and/or omeprazole with or without indomethacin. RE was induced in rats, then gastric acid output, pH, plasma nitric oxide (NO), esophageal PGE2, malondialdehyde (MDA) and reduced glutathione (GSH) were measured and the esophageal injury was assessed by macroscopic damage score.

RESULTS

Pretreatment with BRL significantly increased plasma NO, GSH, decreased acid output, esophageal MDA and esophageal injury in comparison to pretreatment. In addition, there was a no significant increase in esophageal PGE2.

CONCLUSION

It can be concluded that BRL 37344 has an anti-oxidant protective effect in rats with RE.

Proton pump inhibitor use before percutaneous endoscopic gastrostomy is associated with adverse outcomes

BACKGROUND/AIMS

Knowledge of the risk factors associated with adverse outcomes after percutaneous endoscopic gastrostomy (PEG) may be helpful for developing PEG recommendations. The purpose of this study was to identify the clinical risk factors associated with adverse clinical outcomes after PEG, especially regarding the use of proton pump inhibitors (PPIs).

METHODS

We retrospectively reviewed the data from PEG patients at seven university hospitals between June 2006 and January 2012. All patients were followed up through February 2012 after PEG, and the clinical risk factors for adverse clinical outcomes after PEG were analyzed.

RESULTS

Data from 1,021 PEG patients were analyzed. PPI users were more frequently included in the complication group than the noncomplication group (p=0.040). PEG-related complications (p=0.040) and mortality (p=0.003) were more frequent in the PPI group than in the control group. In the subgroup analysis of complicated PEG cases, infectious complications were more frequently found in the PPI group than in the control group (35.8% vs 27.8%). After adjustment for multiple possible confounding factors, PPI users (odds ratio, 1.531; 95% confidence interval, 1.017 to 2.305) and diabetic patients had increased mortality after PEG.

CONCLUSIONS

PPI use may be associated with adverse outcomes in patients with PEG; however, further prospective studies investigating this issue are warranted.

Radiation lethality potentiation in total body irradiated mice by a commonly prescribed proton pump inhibitor, Pantoprazole sodium

PURPOSE

Pantoprazole sodium (Protonix) is a proton pump inhibitor (PPI) widely used to treat peptic ulcer and gastroesophageal reflux due to its ability to inhibit gastric acid secretion. Therefore, a large group of the population exposed to total body irradiation (TBI) in the event of a nuclear disaster would be on this or similar medications. We investigated the effect of pantoprazole on TBI-induced lethality in mice.

METHODS AND MATERIALS

Male CD2F1 mice were exposed to various doses of uniform TBI using a (137)Cs irradiator. Pantoprazole was administered by twice daily subcutaneous injection in saline from 4 days before to 5 days after irradiation. Effects on gastric pH, and gastrointestinal (GI) and hematopoietic toxicity were evaluated.

RESULTS

Pantoprazole administration significantly exacerbated 30 day lethality and gastrointestinal toxicity. Median survival after 9.0 Gy TBI was reduced from 22 days to 12 days (p = 0.006). Pantoprazole adversely effected intestinal crypt survival and mucosal surface area. In contrast, equivalent doses of a histamine type-2(H2) receptor blocker (cimetidine) did not alter TBI-induced lethality.

CONCLUSION

The adverse effect of pantoprazole on TBI-induced lethality is highly important because of the widespread use of PPI in the general population, as well as use of these drugs for acid suppression in individuals exposed to radiation. Further studies of the mechanisms underlying the adverse effect of PPI after exposure to TBI are clearly warranted. Until results from such studies are available, other acid-suppressing strategies should be preferred in the context of radiation exposure.

The effect of omeprazole on the development of experimental autoimmune encephalomyelitis in C57BL/6J and SJL/J mice

BACKGROUND

Gastric disturbances such as dyspepsia are routinely encountered by multiple sclerosis (MS) patients, and these conditions are often treated with gastric acid suppressors such as proton pump inhibitors, histamine H2 receptor antagonists, or antacids. The proton pump inhibitor omeprazole can alter the gut flora and immune responses, both of which can influence the course of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The objective of the current study was to examine the effect of omeprazole treatment on the development of EAE. Bacterial microbiome analysis of mouse fecal pellets was determined in C57BL/6J EAE mice chronically treated with omeprazole, and spleen immune cell content, clinical scores, weight, rotarod latency, and histopathology were used as outcome measures in C57BL/6J and SJL/J mice with EAE.

RESULTS

Omeprazole treatment resulted in decreases in Akkermansia muciniphila and Coprococcus sp. and an increase in unidentified bacteria in the family S24-7 (order Bacteroidales) in C57BL/6J mice with EAE. Omeprazole did not alter spleen immune cell content compared to vehicle in EAE mice, but differences independent of treatment were observed in subsets of T cells between early and advanced disease in C57BL/6J mice as well as between the two strains of mice at an advanced disease stage. Omeprazole caused no difference in clinical scores in either strain, but significantly lowered weight gain compared to vehicle in the C57BL/6J mice with EAE. Omeprazole also did not alter rotarod behavior or hindbrain inflammatory cell infiltration compared to vehicle in both strains of mice with EAE. Rotarod latency did reveal a negative correlation with clinical scores during active disease in both mouse strains, but not during clinical remission in SJL/J mice, suggesting that rotarod can detect disability not reflected in the clinical scores.

CONCLUSIONS

Despite alterations in the gut microbiota and weight gain in the C57BL/6J EAE model, omeprazole had no effect on multiple measures of disease activity in C57BL/6J and SJL/J mice with EAE, supporting the notion that omeprazole does not substantially influence disease activity in MS patients.

Correlation between virulence gene expression and proton pump inhibitors and ambient pH in Clostridium difficile: results of an in vitro study

Proton pump inhibitors (PPIs) are associated with the development of Clostridium difficile infection in humans. Though it is assumed that PPIs mediate this effect through gastric acid suppression, there has been little investigation into whether PPIs, or ambient pH, might directly affect the expression of C. difficile toxin genes. In the present study, C. difficile ribotypes 001, 027 and 078 obtained from human subjects were grown under anaerobic conditions prepared at pHs of 5, 7.3 and 9. Matched trios were exposed to 100 µM and 200 µM of omeprazole along with PPI untreated controls. Custom designed reverse transcription quantitative PCR hydrolysis probes were used to assess C. difficile gene expression for toxins A (tcdA), B (tcdB) and binary toxin (cdtB), as well as their positive regulators (tcdR and cdtR), using rrsA, which encodes 16S rRNA, as a constitutively expressed reference gene. tcdC and codY, negative regulators of toxin expression, were also assessed. Basic pH resulted in greater expression of tcdA, and with PPI exposure a 120-fold higher expression was noted with ribotype 001. tcdB and cdtB expressions were much less responsive to pH or PPIs, though a clear response to acidic pH and PPI exposure was observed in ribotype 027. tcdC and codY expressions were largely unaffected, except with ribotype 027; low pH and PPIs resulted in their greater expression, though to a lesser degree than with toxin genes and their positive regulators. Non-neutral pH and PPI exposure appear to have an effect on C. difficile, one that has a net effect towards toxin gene expression.

Proton pump inhibitors as also inhibitors of atrial fibrillation

Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related upper digestive diseases, including gastric and duodenal ulcer and gastroesophageal reflux disease (GERD). Remarkably, several small clinical trials have shown that these drugs also reduce the symptoms and frequency of atrial fibrillation (AF) episodes in patients treated for comorbid acid reflux. Although the mechanism remains unclear, the effect might pinpoint a connection between GERD and AF. To this end, it is known that both oxidants and inflammation affect initiation and maintenance of AF, and PPIs may reduce symptoms and frequency of AF episodes through their antioxidant and anti-inflammatory effects. This review focuses on the anti-AF effects of PPIs beyond their inhibition of gastric acid production.

A sulfated-polysaccharide fraction from seaweed Gracilaria birdiae prevents naproxen-induced gastrointestinal damage in rats

Red seaweeds synthesize a great variety of sulfated galactans. Sulfated polysaccharides (PLSs) from seaweed are comprised of substances with pharmaceutical and biomedical potential. The aim of the present study was to evaluate the protective effect of the PLS fraction extracted from the seaweed Gracilaria birdiae in rats with naproxen-induced gastrointestinal damage. Male Wistar rats were pretreated with 0.5% carboxymethylcellulose (control group—vehicle) or PLS (10, 30, and 90 mg/kg, p.o.) twice daily (at 09:00 and 21:00) for 2 days. After 1 h, naproxen (80 mg/kg, p.o.) was administered. The rats were killed on day two, 4 h after naproxen treatment. The stomachs were promptly excised, opened along the greater curvature, and measured using digital calipers. Furthermore, the guts of the animals were removed, and a 5-cm portion of the small intestine (jejunum and ileum) was used for the evaluation of macroscopic scores. Samples of the stomach and the small intestine were used for histological evaluation, morphometric analysis and in assays for glutathione (GSH) levels, malonyldialdehyde (MDA) concentration, and myeloperoxidase (MPO) activity. PLS treatment reduced the macroscopic and microscopic naproxen-induced gastrointestinal damage in a dose-dependent manner. Our results suggest that the PLS fraction has a protective effect against gastrointestinal damage through mechanisms that involve the inhibition of inflammatory cell infiltration and lipid peroxidation.

An investigation of the effect of thiamine pyrophosphate on cisplatin-induced oxidative stress and DNA damage in rat brain tissue compared with thiamine

This study investigated the effects of thiamine pyrophosphate (TPP) at dosages of 10 and 20 mg/kg on oxidative stress induced in rat brain tissue with cisplatin and compared this with thiamine. Cisplatin neurotoxicity represents one of the main restrictions on the drug being given in effective doses. Oxidative stress is considered responsible for cisplatin toxicity. Our results showed that cisplatin increased the levels of oxidant parameters such as lipid peroxidation (thio barbituric acid reactive substance (TBARS)) and myeloperoxidase (MPO) in brain tissue and suppressed the effects of antioxidants such as total glutathione (GSH) and superoxide dismutase (SOD). TPP, especially at a dosage of 20 mg/kg, significantly reduced TBARS and MPO levels that increase with cisplatin administration compared with the thiamine group, while TPP significantly increases GSH and SOD levels. In addition, the level of 8-Gua (guanine), a product of DNA damage, was 1.7 ± 0.12 8-hydroxyl guanine (8-OH Gua)/105 Gua in brain tissue in the control group receiving cisplatin, compared with 0.97 ± 0.03 8-OH Gua/105 Gua in the thiamine pyrophosphate (20 mg/kg) group and 1.55 ± 0.11 8-OH Gua/105 Gua in the thiamine (20 mg/kg) group. These results show that thiamine pyrophosphate significantly prevents oxidative damage induced by cisplatin in brain tissue, while the protective effect of thiamine is insignificant.

Biochemical and histologic study of lethal cisplatin nephrotoxicity prevention by mirtazapine

BACKGROUND

Cisplatin is a platinum derivative frequently used in the chemotherapy of different solid tumors. This biochemical and histologic study investigated a possible protective effect of mirtazapine with regard to cisplatin-induced nephrotoxicity in the rat.

METHODS

The animals were divided into 4 groups: 15 mg/kg mirtazapine + 10 mg/kg cisplatin, 30 mg/kg mirtazapine + 10 mg/kg cisplatin, only 10 mg/kg cisplatin and negative control (healthy) group. During 14 days, the treatment and treated control group took drugs, while the healthy animals were given distilled water on the same schedule. All animals were sacrificed by high-dose anesthesia at the end of the 14 days of treatment; their kidneys were removed and subjected to histologic and biochemical study.

RESULTS

In both of the doses we used, mirtazapine decreased the levels of malondialdehyde, creatinine, blood urea nitrogen and myeloperoxidase activity when compared to cisplatin group. On the other hand, it increased total glutathione level in all doses. Slight histopathological findings were determined in mirtazapine groups when compared to cisplatin control group.

CONCLUSION

In the light of our results and literature knowledge, we can conclude that the protective effect of mirtazapine in cisplatin toxicity originates from its own antioxidant activity.

Influence of proton pump inhibitors on dexamethasone-induced gastric mucosal damage in rats

The present study was designed to compare the curative role of proton pump inhibitors, omeprazole, rabeprazole and lansoprazole against dexamethasone-induced ulcer model. Dexamethasone (5 mg/kg/day) was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all rats. Omeprazole (20 mg/kg), rabeprazole (20 mg/kg), and lansoprazole (20 mg/kg) were administered by oral route 30 minutes prior to dexamethasone for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as estimation of myeloperoxidase, cortisol, alkaline phosphatase, malondialdehyde, endogenous anti-oxidants like superoxide dismutase, catalase and reduced glutathione. In dexamethasone induced ulcer model, omeprazole showed significant decrease in malondialdehyde, myeloperoxidase, alkaline phosphatase level and increase in superoxide dismutase, catalase and reduced glutathione level as compared to rabeprazole and lansoprazole. Omeprazole showed significant reduction in cortisol content where as rabeprazole and lansoprazole did not show significant changes as compared to control. The result indicates that omeprazole is the most effective and selective proton pump inhibitor in dexamethasone induced ulcer model as compared to rabeprazole and lansoprazole.

Leaky lysosomes in lung transplant macrophages: azithromycin prevents oxidative damage

Background

Lung allografts contain large amounts of iron (Fe), which inside lung macrophages may promote oxidative lysosomal membrane permeabilization (LMP), cell death and inflammation. The macrolide antibiotic azithromycin (AZM) accumulates 1000-fold inside the acidic lysosomes and may interfere with the lysosomal pool of Fe.

Objective

Oxidative lysosomal leakage was assessed in lung macrophages from lung transplant recipients without or with AZM treatment and from healthy subjects. The efficiency of AZM to protect lysosomes and cells against oxidants was further assessed employing murine J774 macrophages.

Methods

Macrophages harvested from 8 transplant recipients (5 without and 3 with ongoing AZM treatment) and 7 healthy subjects, and J774 cells pre-treated with AZM, a high-molecular-weight derivative of the Fe chelator desferrioxamine or ammonium chloride were oxidatively stressed. LMP, cell death, Fe, reduced glutathione (GSH) and H-ferritin were assessed.

Results

Oxidant challenged macrophages from transplants recipients without AZM exhibited significantly more LMP and cell death than macrophages from healthy subjects. Those macrophages contained significantly more Fe, while GSH and H-ferritin did not differ significantly. Although macrophages from transplant recipients treated with AZM contained both significantly more Fe and less GSH, which would sensitize cells to oxidants, these macrophages resisted oxidant challenge well. The preventive effect of AZM on oxidative LMP and J774 cell death was 60 to 300 times greater than the other drugs tested.

Conclusions

AZM makes lung transplant macrophages and their lysososomes more resistant to oxidant challenge. Possibly, prevention of obliterative bronchiolitis in lung transplants by AZM is partly due to this action.

Drugs that inhibit gastric acid secretion may alter the course of inflammatory bowel disease

BACKGROUND

Recent data suggest that acid suppressive medications may alter factors central to the pathophysiology of inflammatory bowel diseases (IBD), whether through shifts in the intestinal microbiome due to acid suppression or effects on immune function.

AIM

To assess the relationship between the use of proton pump inhibitors (PPIs) or histamine2-receptor antagonists (H2Ra) and incidence of 'flares' (hospitalisation/surgery and change in medication).

METHODS

We conducted a new user cohort study including individuals diagnosed with IBD in British Columbia using linked healthcare utilisation databases (available from July 1996 through April 2006). Propensity-score matched incidence rates during a 6-month follow-up period and rate ratios (RR) and 95% CI were calculated.

RESULTS

Among 16 151 IBD patients, 1307 Crohn's disease (CD) and 996 ulcerative colitis (UC) patients experienced a new use of PPIs, whereas 741 CD and 738 UC used H2Ra. All IBD subgroups were matched separately to an equal number of unexposed IBD patients. H2Ra use in CD doubled the risk of hospitalisation/surgery (RR = 1.94; 95%CI 1.24-3.10) and numerically less so in UC patients (RR = 1.11) with widely overlapping CIs (0.61-2.03). Proton pump inhibitors use was associated with medication change in UC (RR = 1.39; 95%CI 1.20-1.62), but without meaningfully, increased risk of hospitalisation/surgery for UC or CD patients. Extending follow-up showed persistence, but attenuation, of all effects.

CONCLUSIONS

Initiation of PPIs or H2Ra may be associated with short-term changes in the course of IBD. Although confounding by indication was adjusted using propensity score matching, residual confounding may persist and findings need to be interpreted cautiously.

Potential immunological consequences of pharmacological suppression of gastric acid production in patients with multiple sclerosis

Corticosteroids are standard treatment for patients with multiple sclerosis experiencing acute relapse. Because dyspeptic pain is a common side effect of this intervention, patients can be given a histamine receptor-2 antagonist, proton pump inhibitor or antacid to prevent or ameliorate this disturbance. Additionally, patients with multiple sclerosis may be taking these medications independent of corticosteroid treatment. Interventions for gastric disturbances can influence the activation state of the immune system, a principal mediator of pathology in multiple sclerosis. Although histamine release promotes inflammation, activation of the histamine receptor-2 can suppress a proinflammatory immune response, and blocking histamine receptor-2 with an antagonist could shift the balance more towards immune stimulation. Studies utilizing an animal model of multiple sclerosis indicate that histamine receptor-2 antagonists potentially augment disease activity in patients with multiple sclerosis. In contrast, proton pump inhibitors appear to favor immune suppression, but have not been studied in models of multiple sclerosis. Antacids, histamine receptor-2 antagonists and proton pump inhibitors also could alter the intestinal microflora, which may indirectly lead to immune stimulation. Additionally, elevated gastric pH can promote the vitamin B12 deficiency that patients with multiple sclerosis are at risk of developing. Here, we review possible roles of gastric acid inhibitors on immunopathogenic mechanisms associated with multiple sclerosis.

Systematic review: the use of proton pump inhibitors and increased susceptibility to enteric infection

The use of proton pump inhibitors (PPIs) is increasing worldwide. Suppression of gastric acid alters the susceptibility to enteric bacterial pathogens. AIM  This systematic review was undertaken to examine the relationship between PPI use and susceptibility to enteric infections by a specific pathogen based on published literature and to discuss the potential mechanisms of PPI enhanced pathogenesis of enteric infections. METHODS  PubMed, OVID Medline Databases were searched. Search terms included proton pump inhibitors and mechanisms of, actions of, gastric acid, enteric infections, diarrhoea, Clostridium difficile, Salmonella, Shigella and Campylobacter. RESULTS The use of PPIs increases gastric pH, encourages growth of the gut microflora, increases bacterial translocation and alters various immunomodulatory and anti-inflammatory effects. Enteric pathogens show variable gastric acid pH susceptibility and acid tolerance levels. By multiple mechanisms, PPIs appear to increase susceptibility to the following bacterial enteropathogens: Salmonella, Campylobacter jejuni, invasive strains of Escherichia coli, vegetative cells of Clostridium difficile, Vibrio cholerae and Listeria. We describe the available evidence for enhanced susceptibility to enteric infection caused by Salmonella, Campylobacter and C. difficile by PPI use, with adjusted relative risk ranges of 4.2-8.3 (two studies); 3.5-11.7 (four studies); and 1.2-5.0 (17 of 27 studies) for the three respective organisms. CONCLUSIONS Severe hypochlorhydria generated by PPI use leads to bacterial colonisation and increased susceptibility to enteric bacterial infection. The clinical implication of chronic PPI use among hospitalized patients placed on antibiotics and travellers departing for areas with high incidence of diarrhoea should be considered by their physicians.

Inflammation and oxidative stress in gastroesophageal reflux disease

The etiology of esophageal mucosal injury is complex, since it may involve the reflux of gastric acid, bile acid, and pancreatic juice, external factors such as drugs and alcohol, or functional factors such as esophagogastric motility. The mechanism of esophageal mucosal injury has gradually been understood at the molecular biological level. It is particularly important that pro-inflammatory factors, such as inflammatory cytokines (interleukin-6 and -8), leukocytes and oxidative stress, have been demonstrated to be involved in the development of gastroesophageal reflux disease (GERD) including nonerosive reflux disease (NERD). In addition, nociceptors such as acid-sensitive vanilloid receptors, protease-activated receptors and substance P have also been implicated in the pathogenesis of neurogenic inflammation in NERD patients with esophageal hypersensitivity. The development of new therapy with anti-inflammatory and anti-oxidant effects is expected to assist in the treatment of intractable NERD/GERD and the prevention of carcinogenesis.

Proton pump inhibitors and gastritis

Proton pump inhibitors (PPIs) are novel compounds that strongly inhibit the H⁺/K⁺-ATPase in the gastric parietal cells to cause profound suppression of acid secretion. Acid-generating ATPase, also known as vacuolar-type ATPase, is located in the lysozomes of leukocytes and osteoclasts and its activity is also reportedly influenced by treatment with PPIs. This concept is supported by the results of studies using autoradiography in which ³H-Lansoprazole uptake sites were clearly detected in the cytoplasmic granules of neutrophils infiltrating the gastric mucosa. In vitro studies indicate that PPIs increase the intra-vacuolar pH in the lysosomes of purified neutrophils and attenuate the adherence of neutrophils to the vascular endothelium. In clinical practice, the acidic environment in the stomach plays a critical role in the development of gastritis induced by Helicobacter pylori (H. pylori). This is worthy of note, because persistent gastritis often results in atrophic and metaplastic changes in the gastric mucosa, which are believed to be preneoplastic abnormalities. In patients with H. pylori-infection, PPI therapy causes corpus-predominant gastritis, which is frequently found in the background mucosa in patients with gastric cancer. The efficacy and safety of long-term PPI-treatment have not been conclusive, thus we need to pay more attention to the additional pharmacological actions of PPIs.

A matched case-control study of a novel Acid-pump antagonist and proton-pump inhibitor for the treatment of iatrogenic ulcers caused by endoscopic submucosal dissection

BACKGROUND/AIMS

Revaprazan, a novel acid-pump antagonist, and proton-pump inhibitors (PPIs) have pH-independent effects on ulcer healing. The addition of a PPI promotes the cell restitution rate as well as vessel regeneration and maturation for ulcer repair. Revaprazan is known to protect the mucosa by increasing the prostaglandin concentration.

METHODS

We reviewed the medical records of patients who underwent endoscopic submucosal dissection (ESD) for gastric neoplasia at Yeungnam University Hospital between January 2008 and May 2009. We conducted a matched case-control study to compare the healing rates effected by revaprazan and rabeprazole.

RESULTS

Each group consisted of 30 patients. The baseline characteristics did not differ significantly between the two groups. Stage S1 disease was observed in 97% and 100% of patients after 8 weeks of treatment in the revaprazan and rabeprazole groups, respectively. In the revaprazan group, only one patient had stage H2 disease: a 54-year-old man with a 5.5-cm lesion after ESD of the ulcer, type IIa early gastric cancer, and adenocarcinoma. No serious adverse effects occurred during the treatment period in either group.

CONCLUSIONS

The safety and efficacy profiles of revaprazan and rabeprazole are similar for the treatment of ESD-induced ulcers.

Omeprazole promotes gastric epithelial cell migration

Proton pump inhibitors (PPIs) are effective at preventing non-steroidal anti-inflammatory drug (NSAID)-induced gastric ulcers. They are also superior to histamine H2-receptor antagonists and misoprostol in treating NSAID-induced gastric ulcer healing. This study explored whether omeprazole, a PPI, can modulate ulcer healing through epithelial cell proliferation and/or cell migration using a rat normal gastric epithelial cell line (RGM-1). Flow cytometry was used to determine cell proliferation and an artificial wound model was used to measure cell migration. Western blot analysis was performed to evaluate the possible mechanisms of action. Omeprazole treatment (10−8, 10−6 and 10−4M) for 12 and 24 h did not promote cell proliferation. However, similar doses of the drug (10−6 and 10−4 M) incubated for 24–48 h significantly promoted the basal cell migration of gastric epithelial cells. Further, the higher concentration of omeprazole (10−4M) reversed the inhibitory action of indometacin (10−5M) on cell migration. Western blot results showed that omeprazole did not increase cyclooxygenase-2 expression and did not activate signal transduction pathways, including extracellular signal-regulated kinase (ERK1/ERK2), P38 mitogenic-activated protein kinase, and phosphatidyl inositol 3-kinase. The results suggest that omeprazole is beneficial in basal ulcer healing and it reversed the adverse action of indometacin on ulcer repair under acid-independent conditions. These actions are likely to be mediated through the promotion of gastric epithelial cell migration but not cell proliferation.

Potential anti-inflammatory effects of proton pump inhibitors: a review and discussion of the clinical implications

Proton pump inhibitors (PPIs) are potent blockers of gastric acid secretion, and are widely regarded as the agents of choice for the treatment of acid-peptic disorders. For patients with upper gastrointestinal symptoms of uncertain etiology, improvement with PPI therapy is considered prima facie evidence of a pathogenetic role for acid-peptic disease. In addition to anti-secretory effects, however, PPIs have been found to have anti-oxidant properties and direct effects on neutrophils, monocytes, endothelial, and epithelial cells that might prevent inflammation. Those anti-inflammatory effects of the PPIs might influence a variety of inflammatory disorders, both peptic and non-peptic, within and outside of the gastrointestinal tract. The purpose of this report is to review the mechanisms whereby PPIs might exert anti-inflammatory effects exclusive of gastric acid inhibition, to discuss the clinical implications of those effects, and to emphasize that a clinical response to PPIs should not be construed as proof for an underlying acid-peptic disorder.

Antiulcer activity of fluvoxamine in rats and its effect on oxidant and antioxidant parameters in stomach tissue

Background

Although many drugs are available for the treatment of gastric ulcers, often these drugs are ineffective. Many antidepressant drugs have been shown to have antiulcer activity in various models of experimental ulcer. One such drug, the antidepressant mirtazapine, has been reported to have an antiulcer effect that involves an increase in antioxidant, and a decrease in oxidant, parameters. To date, however, there is no information available regarding the antiulcer activity for a similar antidepressant, fluvoxamine. This study aimed to investigate the antiulcer effects of fluvoxamine and to determine its relationship with antioxidants.

Methods

Groups of rats fasted for 24 h received fluvoxamine (25, 50, 100 and 200 mg/kg), ranitidine (50 mg/kg) or distilled water by oral gavage. Indomethacin (25 mg/kg) was orally administered to the rats as an ulcerative agent. Six hours after ulcer induction, the stomachs of the rats were excised and an ulcer index determined. Separate groups of rats were treated with the same doses of fluvoxamine and ranitidine, but not with indomethacin, to test effects of these drugs alone on biochemical parameters. The stomachs were evaluated biochemically to determine oxidant and antioxidant parameters. We used one-way ANOVA and least significant difference (LSD) options for data analysis.

Results

The 25, 50, 100 and 200 mg/kg doses of fluvoxamine exerted antiulcer effects of 48.5, 67.5, 82.1 and 96.1%, respectively, compared to the control rat group. Ranitidine showed an 86.5% antiulcer effect. No differences were observed in the absence of indomethacin treatment for any dose of fluvoxamine or for ranitidine. The levels of antioxidant parameters, total glutathione and nitric oxide, were increased in all fluvoxamine groups and in the ranitidine group when compared with the indomethacin-only group. In addition, fluvoxamine and ranitidine decreased the levels of the oxidant parameters, myeloperoxidase and malondialdeyhyde, in the stomach tissues of the rats when compared to indomethacin group.

Conclusion

We conclude that fluvoxamine has antiulcer effects, and that these occur by a mechanism that involves activation of antioxidant parameters and inhibition of some toxic oxidant parameters.

Management of NSAID-induced gastrointestinal toxicity: focus on proton pump inhibitors

The association between NSAIDs and the presence of upper gastrointestinal (GI) complications is well established. Evidence that acid aggravates NSAID-induced injury provides a rationale for minimizing such damage by acid suppression. Proton pump inhibitors (PPIs) appear to be very effective in treating NSAID-related dyspepsia, and also in healing gastric and duodenal ulcers in patients continuing to receive the NSAID. An analysis of data from comparative studies of PPIs versus ranitidine, misoprostol and sucralfate shows a therapeutic advantage in favour of the PPI. Several studies now confirm the efficacy of co-therapy with PPIs in the short- and long-term prevention of NSAID-induced upper GI injury. PPIs are more effective than histamine H(2)-receptor antagonists at standard dosages in reducing the risk of gastric and duodenal ulcer, and are superior to misoprostol in preventing duodenal but not gastric lesions. However, when balancing effectiveness and tolerance, PPIs may be considered the treatment of choice in the short- and long-term prevention of NSAID-related mucosal lesions. To date, there are only a few published articles dealing with the role of PPIs in the prevention of upper GI complications. Recent epidemiological and interventional studies provide some evidence that PPIs are of benefit. However, more controlled studies using clinical outcomes are needed to establish the best management strategy (PPIs combined with traditional NSAIDs or with cyclo-oxygenase-2 selective inhibitors) especially in patients with multiple risk factors, in patients using concomitant low-dose aspirin, corticosteroids or anticoagulants (high risk group), or in patients with a history of ulcer complications (very high risk group). Furthermore, it should be underlined that Helicobacter pylori infection positively interacts with the gastroprotective effect of PPIs; therefore, the true efficacy of these drugs in preventing NSAID-related ulcer complications should be reassessed without the confounding influence of this microorganism.

Effect of some natural products either alone or in combination on gastritis induced in experimental rats

Gastritis, an inflammatory state in gastric mucosa, can be induced experimentally in various ways. The present study considered the iodoacetamide model (Iodo). Omega-3 fatty acids (fish oil), black seed oil, and curcuminoids (natural products) in addition to omeprazole (synthetic proton-pump inhibitor) were tested. Supplementation of 0.1% iodoacetamide to drinking water of experimental rats for two consecutive weeks resulted in: (i) increased serum nitric oxide (NO) and gastrin, and decreased pepsinogen, (ii) depletion of gastric mucosal glutathione (GSH), and (iii) increased gastric mucosal lipid peroxidation (MDA), but failed to affect gastric mucosal myeloperoxidase (MPO) activity. Histological examination showed marked neutrophilic infiltration after 1 week of iodoacetamide administration and shedding of apical cell layer with pale edematous vacuolated gastric gland cells and thickening of muscularis mucosa after 2 weeks of iodoacetamide intake. Individual administration of omega-3 fatty acids 12 mg/kg, black seed oil 50 mg/kg, and curcuminoids 50 mg/kg body weight orally daily for 3 weeks decreased MDA, gastrin, and NO, and normalized mucosal GSH but failed to affect serum pepsinogen level. Combined administration of these natural products for 3 weeks normalized MPO activity, and other effects were nearly the same as with individual use. Omeprazole administration 30 mg/kg body weight orally daily for 3 weeks induced a similar response except for an observed increase in serum gastrin and pepsinogen levels.