Mucosal Prostaglandin Research Articles

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

BackgroundPanax 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.MethodsWistar 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.ResultsPQS+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.ConclusionsCollectively, 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.

Hydrogen Sulfide-Releasing Indomethacin-Derivative (ATB-344) Prevents the Development of Oxidative Gastric Mucosal Injuries.

Hydrogen sulfide (H2S) emerged recently as an anti-oxidative signaling molecule that contributes to gastrointestinal (GI) mucosal defense and repair. Indomethacin belongs to the class of non-steroidal anti-inflammatory drugs (NSAIDs) and is used as an effective intervention in the treatment of gout- or osteoarthritis-related inflammation. However, its clinical use is strongly limited since indomethacin inhibits gastric mucosal prostaglandin (PG) biosynthesis, predisposing to or even inducing ulcerogenesis. The H2S moiety was shown to decrease the GI toxicity of some NSAIDs. However, the GI safety and anti-oxidative effect of a novel H2S-releasing indomethacin derivative (ATB-344) remain unexplored. Thus, we aimed here to compare the impact of ATB-344 and classic indomethacin on gastric mucosal integrity and their ability to counteract the development of oxidative gastric mucosal injuries. Wistar rats were pretreated intragastrically (i.g.) with vehicle, ATB-344 (7-28 mg/kg i.g.), or indomethacin (5-20 mg/kg i.g.). Next, animals were exposed to microsurgical gastric ischemia-reperfusion (I/R). Gastric damage was assessed micro- and macroscopically. The volatile H2S level was assessed in the gastric mucosa using the modified methylene blue method. Serum and gastric mucosal PGE2 and 8-hydroxyguanozine (8-OHG) concentrations were evaluated by ELISA. Molecular alterations for gastric mucosal barrier-specific targets such as cyclooxygenase-1 (COX)-1, COX-2, heme oxygenase-1 (HMOX)-1, HMOX-2, superoxide dismutase-1 (SOD)-1, SOD-2, hypoxia inducible factor (HIF)-1α, xanthine oxidase (XDH), suppressor of cytokine signaling 3 (SOCS3), CCAAT enhancer binding protein (C/EBP), annexin A1 (ANXA1), interleukin 1 beta (IL-1β), interleukin 1 receptor type I (IL-1R1), interleukin 1 receptor type II (IL-1R2), inducible nitric oxide synthase (iNOS), tumor necrosis factor receptor 2 (TNFR2), or H2S-producing enzymes, cystathionine γ-lyase (CTH), cystathionine β-synthase (CBS), or 3-mercaptopyruvate sulfur transferase (MPST), were assessed at the mRNA level by real-time PCR. ATB-344 (7 mg/kg i.g.) reduced the area of gastric I/R injuries in contrast to an equimolar dose of indomethacin. ATB-344 increased gastric H2S production, did not affect gastric mucosal PGE2 content, prevented RNA oxidation, and maintained or enhanced the expression of oxidation-sensitive HMOX-1 and SOD-2 in line with decreased IL-1β and XDH. We conclude that due to the H2S-releasing ability, i.g., treatment with ATB-344 not only exerts dose-dependent GI safety but even enhances gastric mucosal barrier capacity to counteract acute oxidative injury development when applied at a low dose of 7 mg/kg, in contrast to classic indomethacin. ATB-344 (7 mg/kg) inhibited COX activity on a systemic level but did not affect cytoprotective PGE2 content in the gastric mucosa and, as a result, evoked gastroprotection against oxidative damage.

Molecular docking and anti-ulcerative potential of Cucumis (L. Inodorous) on ibuprofen induced gastric ulceration in male wistar animals

BackgroundThe use of NSAIDs have caused stomach injury by inhibiting endogenous mucosal prostaglandin production. Cucumis melo is reported to possess antiulcer potential. This study investigates the mechanism underlying the antiulcer potentials of Cucumis melo (CUM). MethodsThirty-five male Wistar rat were randomly assigned to each of seven groups; A(control given water and rat pellets), B(gastric ulcer induced with ibuprofen 400 mg/kg), C (Misoprotol 200 μg/kg), D to G (pretreated with different variation of CUM extract; 25 %, 50 %, 75 % and 100 % at a dose of 1 ml/kg for 3 weeks prior to gastric ulcer induction). Ulcer score, ulcer index and percentage inhibition, total gastric acidity was measured. Antioxidant activities, Malondialdehyde, H+/K+ ATPase, PGE2, TNF-α was done by spectrophotometry. Molecular docking investigation of Cucumis melo compounds against Prostaglandin E2 was carried out. Level of significance was tested at P ≤ 0.05 using Tukey post hoc. ResultTotal gastric acidity, ulcer score, ulcer index, MDA, TNF-α significantly decreased after CUM treatment when compared to group B. The percentage inhibition, antioxidant activities, PGE2 concentration was significantly increased in all treatment groups compared to group B. Interactions of selected compounds of CUM with Prostaglandin E2 at various docking pockets showed folic acid has highest binding affinity followed by delta7-avenasterol and codisterol to PGE2 receptor. this study shows that one of the mechanisms by which CUM exhibits its antiulcer potential by enhancing Prostaglandin synthesis and antioxidant capacity. Therefore, Cucumis melo can therefore be explored as novel antiulcer agents.

Olmesartan niosomes ameliorates the Indomethacin-induced gastric ulcer in rats: Insights on MAPK and Nrf2/HO-1 signaling pathway.

Gastric ulcer is a continuous worldwide threat that inquires protective agents. Olmesartan (OLM) has potent anti-oxidant and anti-inflammatory characters, yet having limited bioavailability. We targeted the gastro-protective potential and probable mechanism of OLM and its niosomal form against indomethacin (IND) induced-gastric ulcer in rats. we prepared OLM niosomes (OLM-NIO) with different surfactant: cholesterol molar ratios. We evaluated particle size, zeta-potential, polydispersity, and entrapment efficiency. In-vitro release study, Fourier transform infrared spectroscopy, differential scanning calorimetry, and transmission electron microscopy were performed for selected niosomes. In-vivo, we used oral Omeprazole (30mg/kg), OLM or OLM-NIO (10mg/kg) for 3days before IND (25mg/kg) ingestion. We assessed gastric lesions, oxidative and inflammatory markers. OLM-NIO prepared with span 60:cholesterol ratio (1:1) showed high entrapment efficiency 93 ± 2%, small particle size 159.3 ± 6.8nm, low polydispersity 0.229 ± 0.009, and high zeta-potential -35.3 ± 1.2mV, with sustained release mechanism by release data. In-vivo macroscopical and histological results showed gastro-protective effects of OLM pretreatment, which improved oxidative stress parameters and enhanced the gastric mucosal cyclooxygenase-1 (COX-1) and prostaglandin E2 (PGE2) contents. OLM pretreatment suppressed interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) contents and translocation of p38 mitogen-activated protein kinase (p38-MAPK). Besides, OLM substantially promoted the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) protective pathway. OLM-NIO furtherly improved all previous outcomes. We explored OLM anti-ulcerative effects, implicating oxidative stress and inflammation improvement, mediated by the Nrf2/HO-1 signaling pathway and p38-MAPK translocation. Meanwhile, the more bioavailable OLM-NIO achieved better gastro-protective effects compared to conventional OLM form.

Interaction between the effects of proton pump inhibitors and aspirin on gastric wall sestamibi uptake on myocardial perfusion imaging

BackgroundIncreased gastric wall activity on myocardial perfusion imaging (MPI) is associated with proton pump inhibitor (PPI) therapy; however, the mechanism is unknown. We proposed a role for gastric mucosal prostaglandin synthesis and asked whether concurrent use of aspirin would antagonize this effect. MethodsAn observational study was performed of 319 patients undergoing technetium-99m sestamibi (MIBI) rest/stress MPI. We assessed the effects of taking PPIs, aspirin and their interaction on the principle outcome of clinically significant gastric wall activity. ResultsThe outcome was observed in 13% of patients taking neither a PPI nor aspirin, 22% of those taking aspirin only, 51% taking a PPI only and 33% of those taking both. Adjusted odd ratios (95% confidence intervals) were 6.3 (CI 2.8-14.0; p < .001) for taking a PPI only, 1.8 (CI 0.8-3.9; p = .16) for taking aspirin only, and 3.0 (CI 1.4-6.5; p = .005) for taking the combination of a PPI and aspirin. There was evidence of negative statistical interaction between the two drug effects using additive (p = .006) and multiplicative (p = .016) scales. ConclusionsPPI use was strongly associated with enhanced gastric wall activity on MPI; however, concurrent aspirin appears to reduce the effect. Enhanced local prostaglandin synthesis may mediate the PPI effect.

Comparative study between H. Pylori induced and NSAIDs induced peptic ulcer

The use of Non-steroidal anti-inflammatory drugs as well as the infecting agent H Pylori has been attributed as the prominent common etiological factor for peptic ulcers in patients. Distinguishing proof of Helicobacter pylori as the essential etiologic factor in the improvement of peptic ulcer illness and the perception that the frequency of H. pylori increments with age have brought up the issue of a potential synergistic connection between the presence of H. pylori contamination and NSAID use in the improvement of treatment in gastroenterology. Both H.Pylori and NSAIDs have, nevertheless, been appeared to affect the creation rate and the nature of gastric cyclic AMP, the bodily fluid layer, mucosal prostaglandins, blood stream, and platelet-activating factor. Therefore, it is necessary to determine the risk factors such as age and history of peptic ulcers of the patient prior to prescribing. A co-prescription may be important to reduce the risk of peptic ulcers in patients of high risk. Since H.Pylori infection remains the world's most common chronic bacterial infection, it has been suggested that the establishment of a synergistic or additive effect of H.Pylori infection and NSAID use in the development of peptic ulcer is of great clinical importance as eradication of the bacterium is likely to reduce the risk of upper gastrointestinal complications in infected NSAID users. The prevention and overcoming of NSAIDS induced peptic ulcer and H Pylori induced peptic ulcer is embedded in the thorough understanding and assessment of pathophysiology and other underlying causes in each individual patient. There are wide range of studies that emphasize on the various methods of overcoming these conditions as well as understanding the co factors for the risk of ulcer. The main aim of the treatment is to protect the gastric mucosal layer from further eroding away and heal the mucosal ulcer as soon as possible to avoid further complications.

Gastroprotective effect of cilostazol against ethanol- and pylorus ligation-induced gastric lesions in rats.

Despite the availability of effective antiulcer medications, their suboptimal safety profile ignites the search for alternative/complementary treatments. Drug repositioning is an attractive, efficient, and low-risk strategy. Cilostazol, a clinically used phosphodiesterase 3 inhibitor, has pronounced anti-inflammatory and vasodilatory effects suggesting antiulcer activity. Using ethanol-induced and pyloric ligation-induced gastric ulcer models, we investigated the gastroprotective effect of cilostazol (5 or 10mg/kg, p.o.) in comparison with the standard antiulcer ranitidine (50mg/kg, p.o.) in rats. Gastric mucosa was examined macroscopically, histologically, and biochemically for ulcer severity, markers of oxidative stress, proinflammatory cytokines, apoptotic, and cytoprotective mediators. Gastric acidic output, peptic activity, and mucin content were measured in gastric fluids. Pretreatment with cilostazol reduced ulcer number and severity, ameliorated redox status (reduced glutathione and malonaldehyde content), and decreased levels of IL-1β, IL-6, and TNF-훼 in gastric mucosa, in parallel with increases in mucosal defensive factors nitric oxide (NO), prostaglandin E2 (PGE2), and heat-shock protein 70 (HSP70) promoting mucus secretion, tissue perfusion, and regeneration. Histological examination confirmed the beneficial effects of cilostazol in terms of reducing focal necrosis and infiltration of inflammatory cells, as well as increasing mucopolysaccharide content. These beneficial effects are likely secondary to an increase in cAMP and decrease in apoptosis regulator Bcl-2-associated X protein (BAX). Cilostazol, in a dose-dependent effect, exhibited vasodilatory, anti-inflammatory, and antiapoptotic actions in the gastric mucosa resulting in significant antiulcer activity comparable with the standard drug, ranitidine, but devoid of antisecretory activity. Therefore, its use should be dose and ulcer-inducer dependent.

Protective effect of coptisine free base on indomethacin-induced gastric ulcers in rats: Characterization of potential molecular mechanisms

AimsThe aim of this study was to comparatively investigate the potential gastroprotective effect and underlying mechanisms of coptisine free base (CFB, 8-hydroxy-7, 8-dihydrocoptisine), berberine and lansoprazole against indomethacin-induced gastric ulcer in rats. Materials and methodsCFB (10, 20 and 40mg/kg), berberine (20mg/kg) and lansoprazole (30mg/kg) were orally administrated to rats prior to indometacin ingestion, and gastric lesions were evaluated macroscopically and histologically, and further analyzed by ELISA, qRT-PCR and Western blot. Key findingsCFB exerted comparable or superior gastroprotective effect to berberine in protecting against indomethacin-induced gastric injury. CFB pretreatment significantly enhanced the levels of superoxide dismutase (SOD) and glutathione (GSH), and markedly decreased the malonaldehyde (MDA) content. CFB administration effectively suppressed the levels of myeloperoxidase (MPO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and angiotensin II (Ang II). Besides, CFB substantially up-regulated the mRNA expressions of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), and promoted gastric mucosal prostaglandin E2 level (PGE2). Furthermore, CFB pretreatment remarkably increased the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) from cytosol into the nucleus, and the expression of heme oxygenase-1 (HO-1), while significantly decreased the expression of mitogen activated protein Kinase Kinase 6 (MKK6) and translocation of p38 mitogen-activated protein kinase (p38 MAPK). SignificanceThis was the first investigation reporting the anti-ulcer effect of protoberberine alkaloid free base on in vivo rodent model. The gastroprotective mechanism of CFB might involve favorable regulation of antioxidant and anti-inflammatory status mediated, at least partially, by the Nrf2 signaling pathway and p38 MAPK translocation.

Protective effect of Holothurian intestine against indomethacin induced gastric mucosal damage in rats

Our study aimed to investigate the protective effects of Holothurian intestines (HI) on NSAIDs-induced gastric mucosal damage and the possible mechanism. At first, 60 male Wistar rats were induced of gastric lesions with indomethacin (IDM, 30 mg kg−1). The rats were pretreated for 15 consecutive days with saline, sucralfate, or HI (0.4 g kg−1d−1, 0.8 g kg−1d−1 and 1.6 g kg−1d−1) prior to IDM treatment, followed by evaluations of macroscopic damage and microscopic features; and investigation of the levels of inflammatory cytokines, oxidative stress parameters, gastric mucosal prostaglandin E2 (PGE2) and total hexosamine in tissues. The expression of COX-1 and COX-2 mRNA in the gastric tissue were determined by quantitative polymerase chain reaction (qPCR). Pathological gastric ulcer indexes, levels of pro-inflammatory cytokines (IL-1β, IL-17, TNF-α) and lipid peroxidation were significantly decreased in HI-treated groups, whereas the levels of protective factors (TGF-β, GSH, SOD activity and PGE2) were significantly elevated especially in the group with HI 1.6 g kg−1d−1 (P < 0.05). Furthermore, the expression of COX-2 mRNA decreased significantly in HI groups (P < 0.05). The study investigates that holothurian intestines may act as a kind of marine medicine which have protective effect on IDM-induced gastric ulcer, which could be a dietary preventive agent for the prevention of gastric damage.

Gastroprotective Effect of Vanillin on Indomethacin-Induced Gastric Ulcer in Rats: Protective Pathways and Anti-Secretory Mechanism

Indomethacin provokes aggressive ulcerogenic adverse effects. Natural products with fewer side effects are therefore highly requested to attenuate its gastric ulcer effect. Vanillin is a natural compound widely used as flavoring agent which has antioxidant activity. Therefore, the aim of this study was to investigate its gastroprotective effect against indomethacin induced gastric injury. Rats were divided into four groups; first group served as control, group 2: Treated with indomethacin (25 mg/kg, po.), group 3: Pre-treated with ranitidine (reference drug) (50 mg/kg, po., 5 days) before indomethacin and group 4: Pretreated with vanillin (100 mg/kg, po., 5 days). Pre-treatment with vanillin reduced ulcer index, gastric juice volume, free, total acidity and histopathological changes induced by indomethacin. Although it reduced gastric oxidative stress, it elevated enzymatic antioxidant activity and gastric nitric oxide content. Moreover, it reduced gastric NFκB protein expression and activity as well as inhibition in levels of proinflammatory cytokines, Myeloperoxidase (MPO) and caspase 3 activities. It down regulated gene expression of TNF-α, Cytokine-Induced Neutrophil Chemo Attractant (CINC-2α) and caspase-9 while lacking effect on mucosal prostaglandin E2 (PGE2) level. Collectively, vanillin displayed gastroprotective effects in indomethacin induced gastric ulcer by anti-secretory action and cytoprotective effect via antioxidant and anti-inflammatory activities.

Peptic ulcers: causes, prevention, perforation and treatment

Peptic ulcer disease (PUD) is a sore on the lining of stomach or duodenum. In some cases, a peptic ulcer may develop just above stomach in esophagus, i.e. esophageal ulcer. Peptic ulcer has always been the most common etiology underlying upper gastrointestinal perforation, while gastric perforation represents 10-15% of all peptic ulcers. Alternation in balance between aggressive and protective factors at the luminal surface of the epithelial cells, leads to development of peptic ulcer. Aggressive factors include Helicobacter pylori, hydrochloric acid, pepsins, nonsteroidal anti-inflammatory drugs (NSAIDs), bile acids, ischemia, hypoxia, smoking and alcohol. On the other hands, bicarbonate, mucus layer, mucosal blood flow, prostaglandins (PGs) and growth factors are the most known defensive factors. The shared symptoms include a dull or burning pain in middle or upper stomach between meals or at night, bloating, heartburn, nausea and vomiting are among the most common symptom of peptic ulcer. Some other symptoms in severe cases are dark or black stool (due to bleeding), vomiting blood, weight loss and pain in the mid to upper abdomen. An ulcer may or may not have all or some of the symptoms. In general, ulcers are best diagnosed by instrumental procedures depending on the case and the available facilities in the centre. The most reliable tests include, I) sophagogastroduodenoscopy (EGD), a thin tube with a camera inserted through the mouth into GIT. A biopsy is also taken during an EGD to be examined for H. pylori, II), X-ray for the upper GIT taken after drinking a thick barium salt, III) blood test to check if there is anemia and IV) detection of blood in the stool. Perforation is the major complication of PUD and the perforated peptic ulcer needs the use of surgical intervention. About 80% of the indications for peptic ulcer surgery are related to perforate peptic ulcers. Most cases are treated by simple suture of the perforated intestinal wall. In most cases, the best treatment is surgical or laparoscopic suture closure of the perforated ulcer. Natural products have found a special place in the treatment plans for peptic ulcer disease. They exhibit their antiulcerogenic activities by various mechanisms either prophylactic or therapeutic or both. The prophylactic products have considerable antioxidant and anti-inflammatory activities. On the other hand, therapeutic agents possess antisecretory or healing effects. The anti-H.pylori activity of some plant extracts, however, may explain their antiulcerogenic activity.

NEBIVOLOL AMELIORATES INDOMETHACIN-INDUCED GASTRIC ULCER IN ADULT ALBINO RATS: ROLE OF INDUCIBLE NITRIC OXIDE SYNTHASE

The effect of nebivolol (NBV), a third-generation selective β1- antagonist, on indomethacin (IND) - induced gastric ulcer in rats was investigated. Thirty two male rats were used in this study, divided into four groups as follows: control group, IND ulcer-induced group, IND + NBV (1mg/kg/day, p.o.) group, and IND + NBV (5mg/kg/day, p.o.) group. Gastric ulcer was induced by a single injection of IND (30 mg/Kg, i.p.); NBV was administered for seven days prior to ulcer induction. At the end of the experiment, the stomach of each rat was removed for macroscopic examination and gastric ulcer scoring. The gastric mucosa was prepared for quantitative real-time polymerase chain reaction (qRT-PCR) and tissue homogenate preparation for biochemical study. Then, the remaining part was used for histopathological and immunohistochemical examination. Results showed that NBV significantly protected rats from indomethacin-induced gastric ulceration. There is a significant decreased in the mean ulcer number, score and index along with increased preventive index. Also, NBV significantly decreased the elevations of nitrite⁄nitrate, malondialdehyde, tumor necrosis factor-α, and interleukin-1beta in IND-treated rats. In addition, NBV significantly ameliorated the IND-induced reductions of glutathione level, glutathione peroxidase, superoxide dismutase, and catalase activities, and prostaglandin E2. Moreover, histopathological, immunohistochemical analysis of inducible nitric oxide synthase (iNOS) and qRT-PCR for mRNA expression of iNOS gene:confirmed the biochemical results. It was concluded that NBV renders protection in IND-induced gastric ulceration in rats via maintenance of mucosal nitric oxide and prostaglandin E2, reducing oxidative stress and inflammatory responses.

1068 Direct Evidence for Long-Lasting Acetylation of Cyclooxygenase-1 Associated With Reduction of Colorectal Mucosa Prostaglandin E2 Levels and Ribosomal Protein S6 Phosphorylation by Low-Dose Aspirin in Subjects Undergoing Colorectal Cancer Screening

1068 Direct Evidence for Long-Lasting Acetylation of Cyclooxygenase-1 Associated With Reduction of Colorectal Mucosa Prostaglandin E2 Levels and Ribosomal Protein S6 Phosphorylation by Low-Dose Aspirin in Subjects Undergoing Colorectal Cancer Screening

The role of losartan and enalapril in the protection against stress-induced gastric mucosal ulceration in rats

Background: Angiotensin II (ANG II) is a stress hormone and its level dramatically increases in the stomach during stress. In addition, it generates reactive oxygen species (ROS) with cellular damage and inflammation. So the aim of this study is to evaluate the mechanism of losartan and enalapril in the prevention of stress-induced gastric ulcer through their action on mucosal prostaglandin (PGs) and antioxidant enzymes and compare between them. Methods: Thirty- six adult male wistar albino rats weighing 180-200 g were divided into 6 groups; n= 6. Groups 1, 2, and 3 were received saline (normal control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks. Groups 4, 5, and 6 were pretreated with saline (ulcer control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks duration. On 29 th day, group 4, 5 and 6 were submitted to gastric ulcer by water immersion method, then animals of all groups were sacrificed, stomachs were excised for gross and microscopic examination and determination of the mucosal levels of prostaglandin E2 (PGE2), superoxide dismutase (SOD), nitric oxide (NO) and catalase (CAT). Results: Stress produced gastric ulcer and a significant decrease in all measured gastric parameters compared to normal control group. Pre-treatment of rats with losartan or enalapril decreased the stress-induced alterations in mucosal parameters, but only losartan caused a significant increase in CAT activity in addition. Conclusions: Antagonize the action of ANG II by losartan and enalapril have preventive advantages in stress-induced gastric ulcer and losartan has better influence as it has an additional effect on CAT activity.

Nonsteroidal Anti-inflammatory Drug and Aspirin-induced Peptic Ulcer Disease

Despite decreasing Helicobacter pylori prevalence, the prevalence of peptic ulcer disease is increasing in the aged population, mainly due to increasing use of NSAIDs to manage pain and inflammation. In addition, low dose aspirin is employed as an anti-coagulant for those who have suffered or are at high risk of ischemic stroke and cardiovascular disease. However, NSAIDs and aspirin are injurious to mucosa of stomach and duodenum. NSAID-induced inhibition of mucosal prostaglandin synthesis is thought to be a major mechanism of gastrointestinal mucosal injury. The proportion of elderly has increased rapidly in Korea, with the proportion over 65 years old expected to be 24.3% in 2030. In this higher-risk population, the strategy to reduce the incidence of NSAID-related peptic ulcers and complications such as bleeding, obstruction and perforation is very important. Proton pump inhibitors (PPIs) with cyclooxygenase-2 inhibitor can be used for reducing the risk of NSAID-related ulcers and upper gastrointestinal (GI) complications. However, continuous use of PPI has several problems. In addition, NSAID-related problems in the lower GI tract have increased, in contrast to the decrease of NSAID-related upper GI disease. The aim of this review is to provide an evidence-based knowledge regarding the mechanism, complications of treatment, and prevention strategies for NSAID- or aspirin-related peptic ulcer disease in Korea.

The gastroprotective effect of pogostone from Pogostemonis Herba against indomethacin-induced gastric ulcer in rats.

Pogostemonis Herba, known as "Guang-Huo-Xiang" in Chinese, has been widely used in the treatment of gastrointestinal dysfunction. Pogostone is one of the major constituents of Pogostemonis Herba. The aim was to scientifically evaluate the possible gastroprotective effect and the underlying mechanisms of pogostone against indomethacin-induced gastric ulcer in rats. Rats were orally treated with vehicle, lansoprazole (30 mg/kg) or pogostone (10, 20 and 40 mg/kg) and subsequently exposed to acute gastric lesions induced by indomethacin. Gross evaluation, histological observation, gastric mucosal superoxide dismutase activity, glutathione content, catalase activity, malonaldehyde level and prostaglandin E2 production were performed. Immunohistochemistry and reverse transcription polymerase chain reaction for cyclooxygenase-1 and cyclooxygenase-2, as well as terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, immunohistochemistry for heat-shock protein 70, B-cell lymphoma-2 and Bax were conducted. Results indicated that rats pretreated with pogostone showed remarkable protection from the gastric mucosa damage compared to vehicle-treated rats based on the ulcer index and inhibition percentage. Histologically, oral administration of pogostone resulted in observable improvement of gastric injury, characterized by reduction of necrotic lesion, flattening of gastric mucosa and alleviation of submucosal edema with hemorrhage. Pogostone pretreatment significantly raised the depressed activities of superoxide dismutase, glutathione and catalase, while reduced the elevated malonaldehyde level compared with indomethacin-induced group. Pogostone-pretreated group induced a significant increase in gastric mucosal prostaglandin E2 level and obvious up-regulation of proteinlevelsand mRNA expressions of cyclooxygenase-1 and cyclooxygenase-2. Furthermore, antiapoptotic effect of pogostone was verified by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, and the apoptotic process triggered by pogostone involved the up-expression of heat-shock protein70 and B-cell lymphoma-2 protein, and suppression of Bax protein expressions in the ulcerated tissues. It is speculated that the gastroprotective effect of pogostone against indomethacin-induced gastric ulceration might be associated with its stimulation of cyclooxygenase-mediated prostaglandin E2, antioxidant and antiapoptotic effect.

Sodium caprate-induced increases in intestinal permeability and epithelial damage are prevented by misoprostol

Epithelial damage caused by intestinal permeation enhancers is a source of debate concerning safety. The medium chain fatty acid, sodium caprate (C10), causes reversible membrane perturbation at high dose levels required for efficacy in vivo, so the aim was to model it in vitro. Exposure of Caco-2 monolayers to 8.5mM C10 for 60min followed by incubation in fresh buffer led to (i) recovery in epithelial permeability (i.e. transepithelial electrical resistance (TEER) and apparent permeability coefficient (Papp) of [14C]-mannitol), (ii) recovery of cell viability parameters (monolayer morphology, plasma membrane potential, mitochondrial membrane potential, and intracellular calcium) and (iii) reduction in mRNA expression associated with inflammation (IL-8). Pre-incubation of monolayers with a mucosal prostaglandin cytoprotectant was attempted in order to further decipher the mechanism of C10. Misoprostol (100nM), inhibited C10-induced changes in monolayer parameters, an effect that was partially attenuated by the EP1 receptor antagonist, SC51322. In rat isolated intestinal tissue mucosae and in situ loop instillations, C10-induced respective increases in the [14C]-mannitol Papp and the AUC of FITC-dextran 4000 (FD-4) were similarly inhibited by misoprostol, with accompanying morphological damage spared. These data support a temporary membrane perturbation effect of C10, which is linked to its capacity to mainly increase paracellular flux, but which can be prevented by pre-exposure to misoprostol.

Gastroprotective effect of andrographolide sodium bisulfite against indomethacin-induced gastric ulceration in rats.

Andrographolide sodium bisulfite (ASB), a water-soluble sulfonate of andrographolide has been shown to possess anti-inflammatory, antipyretic and analgesic activities. However, there is no report on the gastroprotective effect of ASB against indomethacin-induced gastric ulcer. Here we investigated the possible anti-ulcerogenic potential of ASB and the underlying mechanism against indomethacin-induced gastric ulcer in rats. The ulcer area, histopathological assessment, contents of gastric mucosal glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), malonaldehyde (MDA) and prostaglandin E2 (PGE2) were examined. In addition, cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) mRNA expression and immunohistochemical evaluation of HSP70, Bcl-2 and Bax proteins were also investigated. Results indicated that ASB pre-treatment significantly reduced the ulcer areas induced by indomethacin compared with the vehicle group. The gastric levels of GSH, CAT and SOD were markedly increased by ASB while the level of MDA was decreased. In addition, ASB pretreatment significantly promoted the gastric PGE2 levels and up-regulated the COX-1 and COX-2 mRNA expression in comparison with the vehicle group. Immunohistochemistry analysis showed obvious up-regulation of HSP70 and Bcl-2 protein expression while suppression of Bax protein in the gastric tissue of ASB-pretreated group. Taken together, these findings indicated that the gastroprotective effect of ASB might be associated with the improvement of antioxidative status, activation of COX-mediated PGE2 synthesis, down-regulation of Bax proteins and up-regulation of Bcl-2 and HSP70 proteins. ASB might have the potential for further development as a promising alternative for antiulcer treatment.

Gastroprotective effect of crocin in ethanol-induced gastric injury in rats

The present study investigated the gastroprotective effect of crocin in ethanol-induced gastric injury in rats. Rats were allocated into a normal group, an ulcer group, a crocin-treated group, an ulcer group pretreated with crocin, and an ulcer group pretreated with omeprazole as a reference anti-ulcer drug. Rats were sacrificed 3h after ethanol administration. Prophylactic administration of crocin (50mg/kg/day, i.p.) for 3 consecutive days before the administration of 70% ethanol (10ml/kg, orally) resulted in significant gastroprotection compared to ethanol-ulcerated rats as manifested by significant reduction in the gastric ulcer index. Crocin pretreatment increased ethanol-lowered levels of gastric juice mucin and mucosal prostaglandin E2 (PGE2) and interleukin-6 (IL-6). Moreover, crocin significantly decreased ethanol-elevated tumor necrosis factor-alpha (TNF-α) level, myeloperoxidase activity and heat shock protein 70 mRNA and protein levels. It also restored ethanol-altered mucosal levels of glutathione, malondialdehyde and superoxide dismutase activity. Furthermore, crocin-pretreatment alleviated ethanol-induced mucosal apoptosis as revealed by significant down-regulation of cytochrome c and caspase-3 mRNA expression, significant decrease in caspase-3 activity and mitigated DNA fragmentation as indicated by significant decrements in comet parameters. The protective efficacy of crocin was further supported by histological assessment. No significant difference was observed between crocin and omeprazole (20mg/kg orally 1h before ethanol administration) regarding their mucin-secretagogue and antioxidant effects, as well as their effects on TNF-α, IL-6 and cytochrome c. On the other hand, omeprazole was superior in enhancing PGE2 level and in alleviating neutrophil infiltration, caspase-3 activation and DNA fragmentation. Conclusively, crocin protects rat gastric mucosa against ethanol-induced injury via anti-inflammatory, anti-oxidative, anti-apoptotic and mucin-secretagogue mechanisms that are probably mediated by enhanced PGE2 release.

Sulindac reversal of 15-PGDH-mediated resistance to colon tumor chemoprevention with NSAIDs.

Non-steroidal anti-inflammatory drugs prevent colorectal cancer by inhibiting cyclooxygenase (COX) enzymes that synthesize tumor-promoting prostaglandins. 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is a tumor suppressor that degrades tumor-promoting prostaglandins. Murine knockout of 15-PGDH increases susceptibility to azoxymethane-induced colon tumors. It also renders these mice resistant to celecoxib, a selective inhibitor of inducible COX-2 during colon neoplasia. Similarly, humans with low colonic 15-PGDH are also resistant to colon adenoma prevention with celecoxib. Here, we used aspirin and sulindac, which inhibit both COX-1 and COX-2, in order to determine if these broader COX inhibitors can prevent colon tumors in 15-PGDH knockout (KO) mice. Unlike celecoxib, sulindac proved highly effective in colon tumor prevention of 15-PGDH KO mice. Significantly, however, aspirin demonstrated no effect on colon tumor incidence in either 15-PGDH wild-type or KO mice, despite a comparable reduction in colonic mucosal Prostaglandin E₂ (PGE₂) levels by both sulindac and aspirin. Notably, colon tumor prevention activity by sulindac was accompanied by a marked induction of lymphoid aggregates and proximal colonic inflammatory mass lesions, a side effect seen to a lesser degree with celecoxib, but not with aspirin. These findings suggest that sulindac may be the most effective agent for colon cancer prevention in humans with low 15-PGDH, but its use may also be associated with inflammatory lesions in the colon.