The role of cyclooxygenase in gastric mucosal protection

Multicomponent reaction for synthesis, molecular docking, and anti-inflammatory evaluation of novel indole-thiazole hybrid derivatives

In this article, novel thiazol-indolin-2-one derivatives 4a-f have been synthesized via treatment of thiosemicarbazide (1) with some isatin derivative 2a-f and N-(4-(2-bromoacetyl)phenyl)-4-tolyl-sulfonamide (3) under reflux in ethanol in the presence of triethyl amine (TEA). The structures of new products were elucidated by elemental and spectral analyses. Moreover, all compounds were investigated for their in vivo anti-inflammatory activity using celecoxib as a reference drug. The target compound 4b was the most active anti-inflammatory candidate and exhibited higher edema inhibition (EI = 38.50%) than that recorded by celecoxib (EI = 34.58%) after 3 h. Furthermore, the most active compounds 4b and 4f were subjected to a molecular docking study inside COX-2 enzyme to show their binding interactions. Both compounds 4b and 4f showed good fitting into COX-2 binding site with docking energy scores - 11.45 kcal/mol and - 10.48 kcal/mol, respectively which indicated that compound 4b revealed the most promising and effective anti-inflammatory potential.

Syringic acid guards against indomethacin-induced gastric ulcer by alleviating inflammation, oxidative stress and apoptosis

The purpose of this study was to evaluate the effects of syringic acid, an anti-oxidant, on indomethacin induced gastric ulcers in rats. Experimental groups were control, ulcer, ulcer treated with 20 mg/kg esomeprazole (a proton pump inhibitor that reduces acid secretion), and ulcer treated with 100 mg/kg syringic acid. Rats were pretreated with esomeprazole or syringic acid two weeks before ulcer induction. Our histopathological observations showed that either syringic acid or esomeprazole attenuated the severity of gastric mucosal damage. Moreover, syringic acid and esomeprazole pretreatments alleviated indomethacin-induced damage by regulating oxidative stress, inflammatory response, the level of transforming growth factor-β (TGF-β), expressions of COX and prostaglandin E2, cell proliferation, apoptosis and regulation of the NF-κB signaling pathway. We conclude that either esomeprazole or syringic acid administration protected the gastric mucosa from harmful effects of indomethacin. Syringic acid might, therefore be a potential therapeutic agent for preventing and treating indomethacin-induced gastric damage.

Molecular docking, characterization, ADME/toxicity prediction, and anti-ulcer activity of new quercetin derivatives on indomethacin-induced gastric ulcer in mice

Gastric ulcer (GU) is a serious upper gastrointestinal tract disorder that affects people worldwide. The drugs now available for GU treatment have a high rate of relapses and drug interactions, as well as mild to severe side effects. As a result, new natural therapeutic medications for treating GU with fewer negative side effects are desperately needed. Because of quercetin's (QCT) diverse pharmacological effects and unique structural features, we decided to semi-synthesize new QCT derivatives and test them for antiulcer activity. Docking assays were performed on the synthesized compounds to determine their affinity for TLR-4/MD-2, MyD88/TIR, and NF-κB domains, an important inflammatory pathway involved in GU development and progression. Mice were given oral famotidine (40 mg/kg/day), QCT, QCT pentamethyl (QPM), or QCT pentaacetyl (QPA) (50 mg/kg/day) for 5 days before GU induction by a single intraperitoneal injection of indomethacin (INDO; 18 mg/kg). QPM and QPA have a stronger binding affinity for TLR-4/MD-2, MyD88/TIR and NF-κB domains than QCT. In comparison, they demonstrated the greatest reduction in ulcer score and index, gastric MDA and nitric oxide (NO) contents, MyD88 and NF-κB expressions, and gastric TLR-4 immunostaining. They also enhanced the levels of GSH, CAT, COX-1, and COX-2 in the gastric mucosa, as well as HO-1 and Nrf2 expression, with histological regression in gastric mucosal lesions, with QPA-treated mice demonstrating the best GU healing. QPA is safe against all of the target organs and adverse pathways studied, with good ADME properties. However, further in vitro experiments are necessary to demonstrate the inhibitory effects of QPM and QPA on the protein targets of interest. In addition, preclinical research on its bioavailability and safety is essential before clinical management can be undertaken. Overall, the new QPA derivative could one day serve as the basis for a new class of potential antiulcer drugs.

Components study on gastroprotective effect and holistic mechanism of the herbal pair Alpinia officinarum - Cyperus rotundus based on spectrum-effect relationship and integrated transcriptome and metabolome analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The herbal pair Alpinia officinarum-Cyperus rotundus (HPAC) has an extended history of use in the treatment of gastric ulcers, and its curative effect is definite.

AIM OF THE STUDY

To explore the material basis and holistic mechanism of HPAC on ethanol-induced gastric ulcers.

MATERIALS AND METHODS

Three chemometrics, GRA, OPLS, and BCA, were used to construct the spectrum-effect relationship between the HPLC fingerprints of HPAC extracts and the bioactivity indices (cell viability; the levels of TNF-α, IL-6, COX-2, and PGE2; and wound healing rate) against GES-1 cell damage to screen the bioactive ingredients. The bioactive components were isolated and validated in vitro. Simultaneously, the effects of HPAC with concentrated bioactive ingredients was tested on ethanol-induced gastric ulcers in vivo, and the mechanism was investigated using transcriptomics and metabolomics. The mechanism was further validated by Western blotting. Finally, the contents of the main components of HPAC were determined before and after compatibility.

RESULTS

Twelve bioactive components were screened, and the structures of nine compounds were confirmed. An in vitro verification test showed that DPHA and galangin could protect GES-1 cells from injury, and that their content increased after compatibility. The CH2Cl2 fraction of HPAC (HP-CH2Cl2) can protect mice from ethanol-induced gastric mucosal injury by reducing hemorrhage and decreasing inflammatory cell infiltration. Western blot analysis indicated that this fraction may up-regulate TRPV1 protein and down-regulate PI3K and AKT proteins.

CONCLUSIONS

DPHA and galangin may be the bioactive components against ethanol-induced GES-1 cell injury. HP-CH2Cl2 may exert gastroprotective effects by regulating PI3K, AKT and TRPV1 proteins.

PDE5 inhibitors and gastric mucosa: implications for the management of peptic ulcer disease

Peptic ulcer disease (PUD) continues to be a cause of significant morbidity and mortality worldwide. Almost two-thirds of PUD cases are asymptomatic. In symptomatic patients, epigastric pain is the most common presenting symptom of PUD, which is manifested by nausea, abdominal fullness, bloating, and dyspepsia. Most PUD cases are associated with the use of COX inhibitors or Helicobacter pylori infection, or both. The traditional management of PUD includes the use of proton pump inhibitors to reduce the gastric acid secretion and antibacterial drugs to combat H. pylori. Timely diagnosis and treatment of PUD are vital to reduce the risk of associated morbidity and mortality, as is prevention of PUD among patients at high risk, including COX inhibitors users and those infected with H. pylori. PDE5 inhibitors have been used for the management of erectile dysfunction and pulmonary hypertension for decades. In recent years, studies have mentioned tremendous pleiotropic effects of PDE5 inhibitors on gastrointestinal, urogenital, musculoskeletal, reproductive, cutaneous, and neurologic disorders. Recent data shows that PDE5 inhibition augments gastric mucosa protection, and here, we review the most recent findings regarding the use of PDE5 inhibitors for the prevention and management of PUD.

Herbal melanin modulates PGE2 and IL-6 gastroprotective markers through COX-2 and TLR4 signaling in the gastric cancer cell line AGS

We reported a gastric anti-ulcerogenic effect of the Nigella sativa (L.)-derived herbal melanin (HM) using rat models. However, the molecular mechanisms underlying this HM gastroprotective effect remain unknown. Cyclooxygenase-2 (COX-2)-catalyzed prostaglandin E2 (PGE2) and toll-like receptor 4 (TLR4)-mediated interleukin-6 (IL-6) production and secretion play major roles in gastric mucosal protection. In the current study, the human gastric carcinoma epithelial cell line AGS was used as a model to investigate the effect of HM on TLR4, COX-2, glycoprotein mucin 4 protein and gene expression using immuno-cyto-fluorescence staining, Western blot technology, and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Gastroprotective markers PGE2 and IL-6 production and secretion were also assessed using an enzyme-linked immunosorbent assay (ELISA). Bacterial lipopolysaccharides (LPS), well-known inducers of TLR4, COX-2, PGE2 and IL-6 expression, were used as a positive control. We showed that HM upregulated its main receptor TLR4 gene and protein expression in AGS cells. HM increased, in a dose- and time-dependent manner, the secretion of PGE2 and the expression of COX-2 mRNA and protein, which was detected in the nucleus, cytoplasm and predominantly at the intercellular junctions of the AGS cells. In addition, HM enhanced IL-6 production and secretion, and upregulated the mucin 4 gene expression, the hallmarks of gastroprotection. To check whether HM-induced PGE2 and IL-6 through TLR4 signaling and COX-2 generated, AGS cells were pre-treated with a TLR4 signaling inhibitor TAK242 and the COX-2 inhibitor NS-398. A loss of the stimulatory effects of HM on COX-2, PGE2 and IL-6 production and secretion was observed in TAK242 and NS-398-pre-treated AGS cells, confirming the role of TLR4 signaling and COX-2 generated in the HM gastroprotective effects. In conclusion, our results showed that HM enhances TLR4/COX-2-mediated secretion of gastroprotective markers PGE2 and IL-6, and upregulates mucin 4 gene expression in the human gastric epithelial cell line AGS, which may contribute to the promising beneficial gastroprotective effect of HM for human gastric prevention and treatment.

Melatonin protects against ketorolac induced gastric mucosal toxic injuries through molecular mechanism associated with the modulation of Arylakylamine N-Acetyltransferase (AANAT) activity

Ketorolac tromethamine (KT), is a widely used non-steroidal anti-inflammatory drug (NSAID) for treating moderate to severe pain. However, the use of KT has been restricted due to its highly toxic attributes that lead to severe gastric ulceration and bleeding. The protective effects of exogenous melatonin (MT) has been reported in conditions associated with gastro-intestinal disorders. This study aims at exploring the role of gastric endogenous MT level and it's metabolizing enzyme AANAT, at the onset of ketorolac mediated toxicities in the gastric mucosa. Gastric mucosal damage was induced in experimental rats by oral administration of graded doses of KT, where 50 mg/kg b.w. of KT was observed to incur maximum gastric lesions. However, gastric damages were found to be protected in rats, pre-treated with 60 mg/kg b.w. of MT. Post-sacrifice, mean ulcer index, oxidative status, total melatonin levels and enzyme activities associated with MT biosynthesis and catabolism were estimated. The results reveal that KT decreases AANAT activity with a concomitant decline in endogenous MT level which cumulatively aggravates gastric toxicity. Moreover, exogenous MT administration has been found to be protective in ameliorating this ulcerogenic process in rats, challenged with KT. Biochemical and histo-pathological observations revealed the reduction in oxidative stress level and replenishment of depleted gastric MT levels in MT pre-treated animals, which might be the causative factors in conferring protection to the gastric tissues and residing mitochondria. The results revealed a correlation between depleted gastric MT level and ulcer formation, which unveiled a novel ulcerogenic mechanism. This may bring forth future therapeutic relevance for treating patients suffering from KT mediated acute gastric toxicities.

Rhizoma Atractylodis Macrocephalae-Assessing the influence of herbal processing methods and improved effects on functional dyspepsia

Background: The unique pharmaceutical methods for the processing of botanical drugs according to the theory of traditional Chinese medicine (TCM) affect clinical syndrome differentiation and treatment. The objective of this study was to comprehensively elucidate the principles and mechanisms of an herbal processing method by investigating the alterations in the metabolites of Rhizoma Atractylodis Macrocephalae (AMR) processed by Aurantii Fructus Immaturus (AFI) decoction and to determine how these changes enhance the efficacy of aqueous extracts in treating functional dyspepsia (FD). Methods: A qualitative analysis of AMR before and after processing was conducted using UPLC-Q-TOF-MS/MS, and HPLC was employed for quantitative analysis. A predictive analysis was then conducted using a network analysis strategy to establish a botanical drug-metabolite-target-disease (BMTD) network and a protein-protein interaction (PPI) network, and the predictions were validated using an FD rat model. Results: A total of 127 metabolites were identified in the processed AMR (PAMR), and substantial changes were observed in 8 metabolites of PAMR after processing, as revealed by the quantitative analysis. The enhanced aqueous extracts of processed AMR (PAMR) demonstrate improved efficacy in treating FD, which indicates that this processing method enhances the anti-inflammatory properties and promotes gastric motility by modulating DRD2, SCF, and c-kit. However, this enhancement comes at the cost of attenuating the regulation of motilin (MTL), gastrin (GAS), acetylcholine (Ach), and acetylcholinesterase (AchE). Conclusion: Through this series of investigations, we aimed to unravel the factors influencing the efficacy of this herbal formulation in improving FD in clinical settings.

Influence of Poloxamer on the Dissolution and Stability of Hot-Melt Extrusion-Based Amorphous Solid Dispersions Using Design of Experiments

The current study aimed to see the effects of poloxamer P407 on the dissolution performance of hydroxypropyl methylcellulose acetate succinate (AquaSolve™ HPMC-AS HG)-based amorphous solid dispersions (ASD). A weakly acidic, poorly water-soluble active pharmaceutical ingredient (API), mefenamic acid (MA), was selected as a model drug. Thermal investigations, including thermogravimetry (TG) and differential scanning calorimetry (DSC), were conducted for raw materials and physical mixtures as a part of the pre-formulation studies and later to characterize the extruded filaments. The API was blended with the polymers using a twin shell V-blender for 10 min and then extruded using an 11-mm twin-screw co-rotating extruder. Scanning electron microscopy (SEM) was used to study the morphology of the extruded filaments. Furthermore, Fourier-transform infrared spectroscopy (FT-IR) was performed to check the intermolecular interactions of the components. Finally, to assess the in vitro drug release of the ASDs, dissolution testing was conducted in phosphate buffer (0.1 M, pH 7.4) and hydrochloric acid-potassium chloride (HCl-KCl) buffer (0.1 M, pH 1.2). The DSC studies confirmed the formation of the ASDs, and the drug content of the extruded filaments was observed to be within an acceptable range. Furthermore, the study concluded that the formulations containing poloxamer P407 exhibited a significant increase in dissolution performance compared to the filaments with only HPMC-AS HG (at pH 7.4). In addition, the optimized formulation, F3, was stable for over 3 months when exposed to accelerated stability studies.

Interpreting the Benefit and Risk Data in Between-Drug Comparisons: Illustration of the Challenges Using the Example of Mefenamic Acid versus Ibuprofen

Evidence-based pain therapy should rely on precisely defined and personalized criteria. This includes balancing the benefits and risks not only of single drugs but often requires complex between-drug comparisons. Non-steroidal anti-inflammatory drugs (NSAIDs) have been available for several decades and their use is described in an abundance of guidelines. Most of these guidelines recommend that ‘the selection of a particular NSAID should be based on the benefit-risk balance for each patient’. However, head-to-head studies are often lacking or of poor quality, reflecting the lower standards for clinical research and regulatory approval at the time. The inconsistency of approved indications between countries due to national applications adds to the complexity. Finally, a fading research interest once drugs become generic points to a general deficit in the post-marketing evaluation of medicines. Far from claiming completeness, this narrative review aimed to illustrate the challenges that physicians encounter when trying to balance benefits and risks in a situation of incomplete and inconsistent data on longstanding treatment concepts. Ibuprofen and mefenamic acid, the most frequently sold NSAIDs in Austria, serve as examples. The illustrated principles are, however, not specific to these drugs and are generalizable to any comparison of older drugs in daily clinical practice.

Therapeutic Versus Preventative Use of Ginkgo biloba Extract (EGb 761) against Indomethacin-Induced Gastric Ulcer in Mice

The main bioactive constituents in the standardized Ginkgo biloba leaf extract (EGb 761) are the terpene lactones and flavonoid glycosides. EGb 761’s antioxidant and anti-inflammatory properties have previously been demonstrated. Indomethacin-induced gastric ulcers have a multifactorial etiology and represent a major restriction to its therapeutic utility. The underlying ulcerogenic process involves oxidative and inflammatory biomolecular insults. This study was performed to explore the curative and preventative benefits of EGb 761 in experimentally-induced ulcers. To develop gastric ulcers in mice, indomethacin (40 mg/kg) was administered orally. EGb 761 (200 mg/kg) was given by gavage for 7 days before (preventative) and after (therapeutic) indomethacin administration. The histological alterations and macroscopic mucosal lesions were assessed. In gastric tissue homogenates, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), and inflammatory cytokines were measured. The expressions of cyclooxygenase-2 (COX-2), cytokines, and proliferating cell nuclear antigen (PCNA) in the stomach mucosa were also investigated. The ulcer index, histological alterations, gastric oxidants, and inflammatory biomarkers were all significantly increased by indomethacin. In stomach specimens, it increased COX-2 and PCNA expression. EGb 761 treatments, both prophylactic and therapeutic, resulted in significant reductions in ulcer lesions, nitrosative and oxidative damage, and inflammatory markers, along with the lowering of COX-2 and PCNA expressions. Furthermore, in the fight against stomach ulcers, EGb 761 treatment was found to be more efficient than prevention.

Heme Oxygenase 1 in Vertebrates: Friend and Foe

HO-1 is the inducible form of the enzyme heme-oxygenase. HO-1 catalyzes heme breakdown, reducing the levels of this important oxidant molecule and generating antioxidant, anti-inflammatory, and anti-apoptotic byproducts. Thus, HO-1 has been described as an important stress response mechanism during both physiologic and pathological processes. Interestingly, some findings are demonstrating that uncontrolled levels of HO-1 byproducts can be associated with cell death and tissue destruction as well. Furthermore, HO-1 can be located in the nucleus, influencing gene transcription, cellular proliferation, and DNA repair. Here, we will discuss several studies that approach HO-1 effects as a protective or detrimental mechanism in different pathological conditions. In this sense, as the major organs of vertebrates will deal specifically with distinct types of stresses, we discuss the HO-1 role in each of them, exposing the contradictions associated with HO-1 expression after different insults and circumstances.

The protective effect of NF-κB signaling pathway inhibitor PDTC on mice with chronic atrophic gastritis

OBJECTIVE

To understand the protective effect of NF-κB signaling pathway inhibitor pyrrolidinedithiocarbamate (PDTC) on mice with chronic atrophic gastritis (CAG).

METHODS

Helicobacter pylori (H. pylori) infection combined with high-salt diet was used to construct the CAG mouse model, and 100 or 200 mg/kg/day PDTC was intragastrically treated for 8 weeks. Then, hematoxylin and eosin (HE) and Alcian blue-periodic acid-Schiff (AB-PAS) staining were used to observe the pathology of gastric mucosa, while immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immuno sorbent assay (ELISA) and western blotting were determined to detect the expression of related molecules.

RESULTS

The nuclear content of NF-κB p65 in the gastric mucosa of the CAG mice was increased accompanying by the structural disorder of the gastric mucosal epithelium, inflammatory cell infiltration, intestinal metaplasia, and increased MUC2 expression, but the symptoms were alleviated after PDTC treatment. In addition, the expressions of TNF-α, IL-1β, IL-6 and COX2 in the gastric mucosa and serum of CAG mice were higher than those control mice, which were reduced in CAG mice treated with either 100 or 200 mg/kg PDTC. Furthermore, 100 mg/kg and 200 mg/kg PDTC treatments reduced the serum PGE₂ in CAG mice with the decreased PCNA and Ki-67 expression in gastric mucosa. The therapeutic effect of 200 mg/kg PDTC was significantly better than that of 100 mg/kg PDTC.

CONCLUSION

PDTC inhibited inflammation and the excessive proliferation of gastric mucosal epithelial cells, thereby exerting a potential therapeutic effect on CAG.

The Role of Organic Small Molecules in Pain Management

In this review, a timeline starting at the willow bark and ending in the latest discoveries of analgesic and anti-inflammatory drugs will be discussed. Furthermore, the chemical features of the different small organic molecules that have been used in pain management will be studied. Then, the mechanism of different types of pain will be assessed, including neuropathic pain, inflammatory pain, and the relationship found between oxidative stress and pain. This will include obtaining insights into the cyclooxygenase action mechanism of nonsteroidal anti-inflammatory drugs (NSAID) such as ibuprofen and etoricoxib and the structural difference between the two cyclooxygenase isoforms leading to a selective inhibition, the action mechanism of pregabalin and its use in chronic neuropathic pain, new theories and studies on the analgesic action mechanism of paracetamol and how changes in its structure can lead to better characteristics of this drug, and cannabinoid action mechanism in managing pain through a cannabinoid receptor mechanism. Finally, an overview of the different approaches science is taking to develop more efficient molecules for pain treatment will be presented.

Effects of a Novel GPR55 Antagonist on the Arachidonic Acid Cascade in LPS-Activated Primary Microglial Cells

Neuroinflammation is a crucial process to maintain homeostasis in the central nervous system (CNS). However, chronic neuroinflammation is detrimental, and it is described in the pathogenesis of CNS disorders, including Alzheimer’s disease (AD) and depression. This process is characterized by the activation of immune cells, mainly microglia. The role of the orphan G-protein-coupled receptor 55 (GPR55) in inflammation has been reported in different models. However, its role in neuroinflammation in respect to the arachidonic acid (AA) cascade in activated microglia is still lacking of comprehension. Therefore, we synthesized a novel GPR55 antagonist (KIT 10, 0.1–25 µM) and tested its effects on the AA cascade in lipopolysaccharide (LPS, 10 ng / mL)-treated primary rat microglia using Western blot and EIAs. We show here that KIT 10 potently prevented the release of prostaglandin E₂ (PGE₂), reduced microsomal PGE₂ synthase (mPGES-1) and cyclooxygenase-2 (COX-2) synthesis, and inhibited the phosphorylation of Ikappa B-alpha (IκB-α), a crucial upstream step of the inflammation-related nuclear factor-kappaB (NF-κB) signaling pathway. However, no effects were observed on COX-1 and -2 activities and mitogen-activated kinases (MAPK). In summary, the novel GPR55 receptor antagonist KIT 10 reduces neuroinflammatory parameters in microglia by inhibiting the COX-2/PGE₂ pathway. Further experiments are necessary to better elucidate its effects and mechanisms. Nevertheless, the modulation of inflammation by GPR55 might be a new therapeutic option to treat CNS disorders with a neuroinflammatory background such as AD or depression.

Arachidonic Acid Derivatives and Neuroinflammation

Neuroinflammation is characterized by dysregulated inflammatory responses localized within the brain and spinal cord. Neuroinflammation plays a pivotal role in the onset of several neurodegenerative disorders and is considered a typical feature of these disorders. Microglia perform primary immune surveillance and macrophage-like activities within the central nervous system. Activated microglia are predominant players in the central nervous system response to damage related to stroke, trauma, and infection. Moreover, microglial activation per se leads to a proinflammatory response and oxidative stress. During the release of cytokines and chemokines, cyclooxygenases and phospholipase A2 are stimulated. Elevated levels of these compounds play a significant role in immune cell recruitment into the brain. Cyclic phospholipase A2 plays a fundamental role in the production of prostaglandins by releasing arachidonic acid. In turn, arachidonic acid is biotransformed through different routes into several mediators that are endowed with pivotal roles in the regulation of inflammatory processes. Some experimental models of neuroinflammation exhibit an increase in cyclic phospholipase A2, leukotrienes, and prostaglandins such as prostaglandin E2, prostaglandin D2, or prostacyclin. However, findings on the role of the prostacyclin receptors have revealed that their signalling suppresses Th2-mediated inflammatory responses. In addition, other in vitro evidence suggests that prostaglandin E2 may inhibit the production of some inflammatory cytokines, attenuating inflammatory events such as mast cell degranulation or inflammatory leukotriene production. Based on these conflicting experimental data, the role of arachidonic acid derivatives in neuroinflammation remains a challenging issue.

Alpha-lipoic acid: A promising adjuvant for nonsteroidal anti-inflammatory drugs therapy with improved efficacy and gastroprotection

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in a wide variety of diseases due to their analgesic and anti-inflammatory effects, but their usage have been limited due to significant ulcerogenic side effects. In the present study, we aimed to evaluate the effect of α-lipoic acid (ALA) treatment on the anti-inflammatory activity of indomethacin (Indo) as well as the possible therapeutic effect of ALA on high dose Indo-induced gastropathy in female mice. Mice were treated with Indo (5 or 30 mg/kg, p.o) alone or in combination with ALA (50, 100 or 200 mg/kg, i.p). in vivo anti-inflammatory effect was evaluated by formalin-induced paw edema measured as paw thickness and edema. Gastric damage was evaluated macroscopically and histologically by scoring mucosal hemorrhage, erosion, edema and inflammation. To our results, Indo was ineffective at 5 mg/kg, but co-treatment with Indo and ALA significantly reduced paw edema, implying that ALA augmented the anti-inflammatory effect of subtherapeutic dose of Indo. However, ALA was not able to induce a further increase in the anti-inflammatory effect of Indo at 30 mg/kg. Unlike the treatment with Indo at 5 mg/kg, Indo at 30 mg/kg caused severe gastric damage that prevented by co-treatment with ALA. These results suggest that combination of ALA with NSAIDs can both increase anti-inflammatory effect and prevent NSAIDs-induced gastric damage. ALA would be promising adjuvant that can reduce dose for effective NSAID therapy, which improves safety profile of NSAIDs especially in cases long-term administration of high dose needed.

"Azole" as privileged heterocycle for targeting the inducible cyclooxygenase enzyme

An over-expression of COX-2 isoenzyme belonging to the Cyclooxygenase Enzyme Family triggers the overproduction of pro-inflammatory prostaglandins that instigate the development of chronic inflammation and related disorders. Hence, the rationally designed drugs for mitigating over-activity of COX-2 isoenzyme play a regulatory role toward the alleviation of the progression of these disorders. However, a selective COX-2 inhibition chemotherapy prompts several side effects that necessitate the identification of novel molecular scaffolds for deliberating state-of-the-art drug designing strategies. The heterocyclic "azole" scaffold, being polar and hydrophilic, possesses remarkable physicochemical advantages for designing physiologically active molecules capable of interacting with a wide range of biological components, including enzymes, peptides, and metabolites. The substituted derivatives of azole nuclei enable a comprehensive SAR analysis for the appraisal of bioactive profile of the deliberated molecules for obtaining the rationally designed compounds with prominent activities. The comprehensive SAR analysis readily prompted the identification of Y-shaped molecules and the eminence of bulkier group for COX-2 selective inhibition. This review presents an epigrammatic collation of the pharmacophore-profile of the chemotherapeutics based on azole motif for a selective targeting of the COX-2 isoenzyme.

Synergistically dual-functional nano eye-drops for simultaneous anti-inflammatory and anti-oxidative treatment of dry eye disease

We have developed a rapid and straightforward topical treatment method for dry eye disease (DED) using poly(catechin) capped-gold nanoparticles (Au@Poly-CH NPs) carrying amfenac [AF; a nonsteroidal anti-inflammatory drug (NSAID)] through effective attenuation of ocular surface tissue damage in dry eyes. A dual-targeted strategy based on ocular therapeutics was adopted to simultaneously block the cyclooxygenase enzymes-induced inflammation and reactive oxygen species (ROS)-induced oxidative stress, the primary two causes of DED. The self-assembled core-shell Au@Poly-CH NPs synthesized via a simple reaction between tetrachloroaurate(iii) and catechin possess a poly(catechin) shell (∼20 nm) on the surface of each Au NP (∼60 nm). The anti-oxidant and anti-inflammatory properties of AF/Au@Poly-CH NPs were evaluated by DCFH-DA and prostaglandin E2/VEGF assays, respectively. Our results demonstrate that Au@Poly-CH NPs not only act as an anti-oxidant to suppress ROS-mediated processes, but also serve as a drug carrier of AF for a synergistic effect on anti-inflammation. In vivo biocompatibility studies show good tolerability of AF/Au@Poly-CH NPs for potential use in the treatment of ocular surface pathologies. The dual-targeted therapeutic effects of AF/Au@Poly-CH NPs lead to rapid recovery from DED in a rabbit model. Au@Poly-CH NPs loaded with NSAIDs is a promising multifunctional nanocomposite for treating various inflammation- and oxidative stress-related diseases.

Management of NSAID-associated peptic ulcer disease

Non-steroidal anti-inflammatory drug (NSAID) use increases the risk of gastrointestinal complications such as ulcers or bleeding. The presence of factors like advanced age, history of peptic ulcer, Helicobacter pylori infection and the use of anticoagulants or antiplatelet agents increase this risk further. COX-2 inhibitors and antisecretory drugs, particularly proton pump inhibitors, help to minimize the risk of gastrointestinal complications in high-risk patients. This review presents a practical approach to the prevention and treatment of NSAID-associated peptic ulcer disease and examines the new advances in the rational use of NSAIDs.

Benexate hydrochloride betadex modulates nitric oxide synthesis and cytokine expression in gastric ulcers

The present study investigated benexate hydrochloride betadex (BHB)-mediated ulcer healing, and changes to microcirculation modulated through nitric oxide synthase (NOS) and anti-inflammatory activity. A rat model of gastric mucosal injury was established through injection of a 60% acetic acid solution into the stomach. Following ulcer induction, the rats were administered BHB orally for 5 days at doses of 0, 100, 300 or 1,000 mg/kg. The highest dose of BHB was also administered with or without L-NG-nitroarginine methyl ester (L-NAME). The area of gastric ulcers was determined by planimetry, and expression of cyclooxygenases (COX), cytokines and NOS in stomach tissues were measured using western blotting. Compared with the control group, gastric ulcer size was significantly decreased in the 1,000 mg/kg BHB-treated group (P<0.05). Administration of BHB led to a significant increase in endothelial (e)NOS expression (P<0.05). Although acetic acid co-treatment with L-NAME induced more severe mucosal damage, BHB decreased COX expression and tumor necrosis factor-α levels when administered with the nitric oxide inhibitor, L-NAME (P<0.05). BHB exhibited protective effects in a rat model of gastric ulcers, which were associated with a decrease in pro-inflammatory cytokine levels and the activation of eNOS.

Protective activity of crocin against indomethacin-induced gastric lesions in rats

The present study was designed to elucidate the mechanism(s) of the gastro-protective effect of crocin against indomethacin-induced gastric lesions. Crocin or pantoprazole was administered to rats 30 min before indomethacin. Five hours later, the animals were killed and their stomachs were removed and examined macroscopically. Samples of gastric mucosa were collected for microscopic evaluation, mRNA expression of caspase-3, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 was quantified by RT-PCR, and protein levels of COX-1, COX-2, iNOS and caspase-3 were assessed by Western blotting. The pH, volume of gastric effluent and antioxidant activity were measured in 5 separate groups of rats following pylorus ligation. Indomethacin induced significant increases in mRNA and protein expression of iNOS and caspase-3 and increased MDA levels, and reduced the pH of the gastric effluent and protein and mRNA expression of COX-2 and protein expression of COX-1 and mucus content associated with gastric ulceration. Crocin and pantoprazole significantly inhibited mRNA and protein expression of iNOS, caspase-3 and MDA, and reduced mucus content induced by indomethacin. However, unlike pantoprazole, crocin failed to increase COX-1 and pH, but had variable increasing effects on mRNA and protein expression of COX-2. Macroscopic and microscopic observations showed that mucosal erosions induced by indomethacin were significantly inhibited by pantoprazole and crocin. These findings suggest that crocin exerts its gastro-protective effects mainly by inhibition of MDA, reduction in iNOS and caspase-3, and inhibition of the reduction in mucus content induced by indomethacin. Crocin is a novel agent that has potential in the prevention of ulceration induced by NSAIDs.

Molecular basis for nonspecificity of nonsteroidal anti-inflammatory drugs (NSAIDs)

Inhibition of the production of inflammatory mediators by the action of nonsteroidal anti-inflammatory drugs (NSAIDs) is highly accredited to their recognition of cyclooxygenase enzymes. Along with inflammation relief, however, NSAIDs also cause adverse effects. Although NSAIDs strongly inhibit enzymes of the prostaglandin synthesis pathways, several other proteins also serve as fairly potent targets for these drugs. Based on their recognition pattern, these receptors are categorised as enzymes modifying NSAIDs, noncatalytic proteins binding to NSAIDs and enzymes with catalytic functions that are inhibited by NSAIDs. The extensive binding of NSAIDs is responsible for their limited in vivo efficacy as well as the large spectrum of their effects. The biochemical nature of drugs binding to multiple protein targets and its implications on physiology are discussed.

S-allyl cysteine alleviates nonsteroidal anti-inflammatory drug-induced gastric mucosal damages by increasing cyclooxygenase-2 inhibition, heme oxygenase-1 induction, and histone deacetylation inhibition

BACKGROUND AND AIM

Nonsteroidal anti-inflammatory drugs (NSAIDs), the most highly prescribed drugs in the world for the treatment of pain, inflammation, and fever, are associated with gastric mucosal damages including ulcer directly or indirectly. This study was aimed to document the preventive effects of an organosulfur constituent of garlic, S-allyl cysteine (SAC), against NSAIDs-induced gastric damages, as well the elucidation of its pharmacological actions, such as anti-inflammatory, anti-oxidative, and cytoprotective actions.

METHODS

Different doses of SAC were administrated intragastrically before the indomethacin administration. After killing, in addition to gross and pathological evaluations of ulcer, the expressions of inflammatory mediators, including cyclooxygenase-2, prostaglandin E2 , IL-1β, tumor necrosis factor-α, IL-6, and anti-oxidant capacity, were analyzed by Western blot analysis or ELISA, respectively. Transferase deoxytidyl uridine end labeling assay, periodic acid and Schiff staining, F4/80 staining, and CD31 staining were compared among doses of SAC. Detailed documentation of in vitro biological actions of SAC, including NF-κB, histone deacetylator inhibition, phase 2 enzyme, and MAPKs, was performed.

RESULTS

SAC was very effective in preventing indomethacin-induced gastric damages in a low dose through significant decreases in macrophage infiltration as well as restorative action. Indomethacin-induced expressions of inflammatory mediators were all significantly attenuated with SAC in accordance with histone deacetylator inhibition. In addition, SAC significantly increased the total anti-oxidant concentration and mucus secretion, and allows for a significant induction of HO-1. However, these preventive effects of SAC were dependent on dosage of SAC; higher dose above 10 μM paradoxically aggravated NSAID-induced inflammation.

CONCLUSION

Synthetic SAC can be promising therapeutics agent to provide potent anti-inflammatory, anti-oxidative, and mucosa protective effects against NSAID-induced damages.

The role of gastrokine 1 in gastric cancer

Homeostatic imbalance between cell proliferation and death in gastric mucosal epithelia may lead to gastritis and gastric cancer. Despite abundant gastrokine 1 (GKN1) expression in the normal stomach, the loss of GKN1 expression is frequently detected in gastric mucosa infected with Helicobacter pylori, as well as in intestinal metaplasia and gastric cancer tissues, suggesting that GKN1 plays an important role in gastric mucosal defense, and the gene functions as a gastric tumor suppressor. In the stomach, GKN1 is involved in gastric mucosal inflammation by regulating cytokine production, the nuclear factor-κB signaling pathway, and cyclooxygenase-2 expression. GKN1 also inhibits the carcinogenic potential of H. pylori protein CagA by binding to it, and up-regulates antioxidant enzymes. In addition, GKN1 reduces cell viability, proliferation, and colony formation by inhibiting cell cycle progression and epigenetic modification by down-regulating the expression levels of DNMT1 and EZH2, and DNMT1 activity, and inducing apoptosis through the death receptor-dependent pathway. Furthermore, GKN1 also inhibits gastric cancer cell invasion and metastasis via coordinated regulation of epithelial mesenchymal transition-related protein expression, reactive oxygen species production, and PI3K/Akt signaling pathway activation. Although the modes of action of GKN1 have not been clearly described, recent limited evidence suggests that GKN1 acts as a gastric-specific tumor suppressor. This review aims to discuss, comment, and summarize the recent progress in the understanding of the role of GKN1 in gastric cancer development and progression.

Positive and negative effects of prostaglandins in Alzheimer's disease

The aim of this review was to clarify the role of prostaglandins and prostaglandin receptors in the immunopathology of Alzheimer's disease. A PubMed search was done using the key word, 'Alzheimer's disease' in combination with the term 'prostaglandins'. Articles from the past 10 years were preferentially selected but important ones from the past 20 years were also included according to the authors' judgment. Alzheimer's disease is characterized by pathological hallmarks such as extracellular deposition of the amyloid β-peptide, the appearance of intracellular neurofibrillary tangles, extensive neuronal loss and synaptic changes in the cerebral cortex and hippocampus. These processes induce inflammatory pathways by activating microglia, astrocytes and infiltrating leukocytes that produce inflammatory mediators including cytokines and prostaglandins.Prostaglandins are small lipid mediators derived from arachidonic acid by multi-enzymatic pathways in which cyclooxygenases and phospholipases are the rate-limiting enzymes. In the central nervous system, prostaglandins exhibit either neurotoxic or neuroprotective effects by acting on specific G-protein-coupled receptors that have different subfamilies and differences in their selective agonists, tissue distribution and signal transduction cascades. Further studies on the role of prostaglandins in Alzheimer's disease may contribute to clarification of their neuroprotective actions, which may lead to the development of successful therapeutic strategies.

Preventive efficacy and safety of rebamipide in nonsteroidal anti-inflammatory drug-induced mucosal toxicity

Background/Aims

The use of proton pump inhibitors or misoprostol is known to prevent the gastrointestinal complications of nonsteroidal anti-inflammatory drugs (NSAIDs). Rebamipide is known to increase the mucosal generation of prostaglandins and to eliminate free oxygen radicals, thus enhancing the protective function of the gastric mucosa. However, it is unknown whether rebamipide plays a role in preventing NSAID-induced gastropathy. The aim of this study was to determine the effectiveness of rebamipide compared to misoprostol in preventing NSAID-induced gastrointestinal complications in patients requiring continuous NSAID treatment.

Methods

We studied 479 patients who required continuous NSAID treatment. The patients were randomly assigned to groups that received 100 mg of rebamipide three times per day or 200 μg of misoprostol three times per day for 12 weeks. The primary endpoint of the analysis was the occurrence rate of gastric ulcers, as determined by endoscopy after 12 weeks of therapy.

Results

Of the 479 patients in the study, 242 received rebamipide, and 237 received misoprostol. Ultimately, 44 patients (18.6%) withdrew from the misoprostol group and 25 patients (10.3%) withdrew from the rebamipide group. There was a significant difference in withdrawal rate between the two groups (p=0.0103). The per protocol analysis set was not valid because of the dropout rate of the misoprostol group; thus, the intention to treat (ITT) analysis set is the main set for the efficacy analysis in this study. After 12 weeks, the occurrence rate of gastric ulcers was similar in the rebamipide and misoprostol groups (20.3% vs 21.9%, p=0.6497) according to ITT analysis. In addition, the therapeutic failure rate was similar in the rebamipide and misoprostol groups (13.6% vs 13.1%, p=0.8580). The total severity score of the gastrointestinal symptoms was significantly lower in the rebamipide group than in the misoprostol group (p=0.0002). The amount of antacid used was significantly lower in the rebamipide group than in the misoprostol group (p=0.0258).

Conclusions

Rebamipide can prevent gastric ulcers when used with NSAIDs and can decrease the gastrointestinal symptoms associated with NSAID administration. When the possibility of poor compliance and the potential adverse effects of misoprostol are considered, rebamipide appears to be a clinically effective and safe alternative.

COX-2 Gene Promoter Methylation in Patients Infected with Helicobacter Pylori

Cyclooxygenase (COX) plays a critical role in peptic ulcer development. COX-2 contains CpG islands in promoter area, which suggests possible epigenetic mechanisms of gene silencing. We evaluated COX-2 gene promoter methylation levels in the gastric mucosa of patients with various gastric diseases. DNA was extracted from endoscopic biopsy materials collected from the gastric mucosa. The methylation levels of the COX-2 gene promoter were measured quantitatively by using pyrosequencing. COX-2 mRNA expression in Kato III and AGS cells was measured using real-time PCR. COX-2 gene promoter methylation levels were significantly higher in Helicobacter pylori (HP)-positive cases than in HP-negative cases (27.5% vs. 8.1%, respectively, P < 0.001). COX-2 gene promoter methylation levels in patients in whom HP was successfully eradicated were significantly lower than those in HP-positive cases (18.7% vs. 27.5%, respectively, P < 0.01). We then investigated the effects of COX-2 gene promoter methylation on its mRNA expression in vitro. COX-2 mRNA expression was not observed in Kato III cells, despite the addition of the protein kinase C stimulator α-phorbol 12,13-dibutyrate (PDBu). COX-2 expression was observed after the addition of the demethylating agent 5-Aza-dC and was enhanced by PDBu. HP infection caused a significant increase in the methylation levels of the COX-2 gene promoter in the gastric mucosa. In addition to transcriptional regulation, COX-2 expression is regulated through epigenetic mechanisms.

Current perspectives in NSAID-induced gastropathy

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most highly prescribed drugs in the world. Their analgesic, anti-inflammatory, and antipyretic actions may be beneficial; however, they are associated with severe side effects including gastrointestinal injury and peptic ulceration. Though several approaches for limiting these side effects have been adopted, like the use of COX-2 specific drugs, comedication of acid suppressants like proton pump inhibitors and prostaglandin analogs, these alternatives have limitations in terms of efficacy and side effects. In this paper, the mechanism of action of NSAIDs and their critical gastrointestinal complications have been reviewed. This paper also provides the information on different preventive measures prescribed to minimize such adverse effects and analyses the new suggested strategies for development of novel drugs to maintain the anti-inflammatory functions of NSAIDs along with effective gastrointestinal protection.

Prostaglandins and rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, autoimmune, and complex inflammatory disease leading to bone and cartilage destruction, whose cause remains obscure. Accumulation of genetic susceptibility, environmental factors, and dysregulated immune responses are necessary for mounting this self-reacting disease. Inflamed joints are infiltrated by a heterogeneous population of cellular and soluble mediators of the immune system, such as T cells, B cells, macrophages, cytokines, and prostaglandins (PGs). Prostaglandins are lipid inflammatory mediators derived from the arachidonic acid by multienzymatic reactions. They both sustain homeostatic mechanisms and mediate pathogenic processes, including the inflammatory reaction. They play both beneficial and harmful roles during inflammation, according to their site of action and the etiology of the inflammatory response. With respect to the role of PGs in inflammation, they can be effective mediators in the pathophysiology of RA. Thus the use of agonists or antagonists of PG receptors may be considered as a new therapeutic protocol in RA. In this paper, we try to elucidate the role of PGs in the immunopathology of RA.

Effect of mosapride on prednisolone-induced gastric mucosal injury and gastric-emptying disorder in dog

Previous report demonstrated that prokinetic agent mosapride has anti-ulcerogenic action in rat-indomethacin gastric mucosal injury model. Here, we assessed the prophylactic effect of mosapride on gastric mucosal injury and emptying disorder induced by prednisolone in dogs. Crossover study design was employed. Six healthy beagles were administered prednisolone alone (2 mg/kg, twice a day [BID] subcutaneously) and prednisolone with mosapride (1 mg/kg, BID, orally), followed by an interval of at least 6 weeks. In each treatment, gastric mucosal injury was scored endoscopically according to the modified Lanza scale, and gastric emptying was assessed with (13)C-octanoic acid breath test. The incidence of gastrointestinal adverse events was also investigated. Coadministration of mosapride with prednisolone significantly (P<0.05) reduced the gastric mucosal injury score (mean ± SD, 17.67 ± 6.96), compared with that of prednisolone treatment alone (25.50 ± 13.03). Prednisolone treatment delayed the half-emptying time (184 ± 45 min) compared with that of controls (137 ± 19 min), and coadministration of mosapride improved this gastric-emptying delay (143 ± 29 min). Furthermore, the incidence of the gastrointestinal adverse event vomiting became less frequent upon coadministration with mosapride. In addition to its prokinetic action, our study suggests that mosapride has an anti-ulcerogenic action in dogs. The use of mosapride in combination with prednisolone is effective for attenuating prednisolone-induced gastrointestinal adverse events.

Delayed production of arachidonic acid contributes to the delay of proteinase-activated receptor-1 (PAR1)-triggered prostaglandin E2 release in rat gastric epithelial RGM1 cells

Proteinase-activated receptor-1 (PAR1), upon activation, exerts prostanoid-dependent gastroprotection, and increases prostaglandin E(2) (PGE(2)) release through cyclooxygenase-2 (COX-2) upregulation in rat gastric mucosal epithelial RGM1 cells. However, there is a big time lag between the PAR1-triggered PGE(2) release and COX-2 upregulation in RGM1 cells; that is, the former event takes 18 h to occur, while the latter rapidly develops and reaches a plateau in 6 h. The present study thus aimed at clarifying mechanisms for the delay of PGE(2) release after PAR1 activation in RGM1 cells. Although a PAR1-activating peptide, TFLLR-NH(2), alone caused PGE(2) release at 18 h, but not 6 h, TFLLR-NH(2) in combination with arachidonic acid dramatically enhanced PGE(2) release even for 1-6 h. TFLLR-NH(2) plus linoleic acid caused a similar rapid response. CP-24879, a Δ(5)/Δ(6)-desaturase inhibitor, abolished the PGE(2) release induced by TFLLR-NH(2) plus linoleic acid, but not by TFLLR-NH(2) alone. The TFLLR-NH(2)-induced PGE(2) release was not affected by inhibitors of cytosolic phospholipase A(2) (cPLA(2)), Ca(2+)-independent PLA(2) (cPLA(2)) or secretory PLA(2) (sPLA(2)), but was abolished by their mixture or a pan-PLA(2) inhibitor. Among PLA(2) isozymes, mRNA of group IIA sPLA(2) (sPLA(2)-IIA) was upregulated following PAR1 stimulation for 6-18 h, whereas protein levels of PGE synthases were unchanged. These data suggest that the delay of PGE(2) release after COX-2 upregulation triggered by PAR1 is due to the poor supply of free arachidonic acid at the early stage in RGM1 cells, and that plural isozymes of PLA(2) including sPLA(2)-IIA may complementarily contribute to the liberation of free arachidonic acid.

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

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

Prostaglandins in pathogenesis and treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) characterized by inflammation, demyelination, axonal loss, and gliosis. The inflammatory lesions are manifested by a large infiltration and a heterogeneous population of cellular and soluble mediators of the immune system, such as T cells, B cells, macrophages, and microglia, as well as a broad range of cytokines, chemokines, antibodies, complement, and other toxic substances. Prostaglandins (PGs) are arachidonic acid-derived autacoids that have a role in the modulation of many physiological systems including the CNS, respiratory, cardiovascular, gastrointestinal, genitourinary, endocrine, and immune systems. PG production is associated with inflammation, a major feature in MS that is characterized by the loss of myelinating oligodendrocytes in the CNS. With respect to the role of PGs in the induction of inflammation, they can be effective mediators in the pathophysiology of MS. Thus use of agonists or antagonists of PG receptors may be considered as a new therapeutic protocol in MS. In this review, we try to clarify the role of PGs in immunopathology and treatment of MS.

The 5-HT4 receptor agonist mosapride attenuates NSAID-induced gastric mucosal damage

BACKGROUND

The cholinergic anti-inflammatory pathway is a novel physiological mechanism found at various locations in the body where the nicotinic regulation of inflammatory cells through the autonomic nervous system is involved. In this study, we tested the hypothesis that cholinergic nerve stimulation by a 5-HT(4) agonist may modulate the progression of gastric mucosal ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

Acute gastric ulcers were induced in rats by the oral administration of indomethacin.

RESULTS

Gastric damage analysis indicated that pretreatment with mosapride, a selective 5-HT(4) agonist, at 0.25, 0.5, and 0.75 mg/kg, inhibited the mucosal damage induced by indomethacin. In gastric emptying analysis, an evacuation effect was observed in the 3.0 mg/kg mosapride pretreatment group, but this effect was not observed in the lower dose (0.5 mg/kg) group. The antiulcerogenic activity of mosapride treatment (at 0.5 mg/kg) was blocked by a 5-HT(4)-specific antagonist, GR113808 (1 mg/kg, i.v.). Additionally, we demonstrated that methyllycaconitine (0.29 and 0.87 mg/kg i.p.), a selective inhibitor of alpha7 nicotinic acetylcholine (ACh) receptors (alpha7nAChRs), ablated the antiulcerogenic action of mosapride.

CONCLUSIONS

These results suggest that the mucosal protective action of mosapride may be mediated by an action on immune cells through the acceleration of ACh release from parasympathetic nerves via the activation of 5-HT(4) receptors, followed by activation of the nicotinic anti-inflammatory system. It appears that the alpha7nAChR may be involved in the antiulcerogenic action of mosapride.

Efficacy and Safety of Celecoxib in the Treatment of Acute Pain due to Ankle Sprain in a Latin American and Middle Eastern Population

Ankle sprains are common acute soft-tissue injuries. This 7-day open-label, multicentre, randomized study compared the efficacy and safety of celecoxib with non-selective non-steroidal antiinflammatory drugs (NSAIDs) in treating acute ankle sprain with moderate-to-severe ankle pain in 278 patients. Patients received either celecoxib (400 mg loading dose followed by 200 mg twice daily) or standard doses of non-selective NSAIDs. The primary endpoint was a change in the patient's assessment of ankle pain on a 0 mm (no pain) −100 mm (worst possible pain) visual analogue scale (VAS) at day 3 compared with baseline. From a baseline of 73 mm, mean VAS pain scores decreased to 29 and 32 mm in the celecoxib and non-selective NSAID groups, respectively. The lower limit of the 95% confidence interval for the treatment difference with regard to change from baseline was greater than the pre-established non-inferiority margin of −10 mm. Using an initial loading dose, celecoxib was at least as efficacious as non-selective NSAIDs in treating acute pain due to ankle sprain.

Influence of cyclooxygenase inhibitors on the function of the prostaglandin transporter organic anion-transporting polypeptide 2A1 expressed in human gastroduodenal mucosa

The human organic anion-transporting polypeptide 2A1 (OATP2A1) is a prostaglandin transporter expressed in several tissues and plays an important role for local distribution of prostaglandins, which contribute to the integrity of gastric mucosa. Blockade of prostaglandin pathways by cyclooxygenase (COX) inhibitors has been associated with serious side effects such as gastrointestinal ulceration and bleeding. However, little is known regarding OATP2A1 expression in the upper gastrointestinal tract and the potential impact of cyclooxygenase inhibitors on OATP2A1 function. We first investigated the expression of OATP2A1 mRNA and protein in human gastroduodenal mucosa using human biopsy specimens obtained from antrum, corpus, and duodenum. The results indicate that OATP2A1 is expressed in the neck region and deep pyloric glands of antrum and in parietal cells of gastric corpus. Second, we examined various COX inhibitors for their effects on OATP2A1 transporter activity. Using HEK293 cells expressing OATP2A1, we found that diclofenac and lumiracoxib are potent inhibitors of OATP2A1-mediated transport of prostaglandin (PG) E(2) with IC(50) values of 6.2 +/- 1.2 and 3.1 +/- 1.2 microM. In contrast, indomethacin, ketoprofen, and naproxen led to significant stimulation of OATP2A1-mediated PGE(2) transport by 162.7 +/- 13.9, 77.2 +/- 3.6, and 32.3 +/- 4.9%, respectively. Taken together, our results suggest that various clinically used COX inhibitors have differential impact on the function of the prostaglandin transporter OATP2A1 in human stomach and that these effects may contribute to differences in the gastrointestinal side effects of COX inhibitors.

Characterization of mechanisms underlying the effects of esomeprazole on the impairment of gastric ulcer healing with addition of NSAID treatment

BACKGROUND

The efficacy of proton pump inhibitors in patients at high risk of gastrointestinal injury receiving non-steroidal anti-inflammatory drugs is currently debated.

AIMS

To evaluate the effects of esomeprazole on the impairment of gastric ulcer healing associated with non-steroidal anti-inflammatory drug treatment.

METHODS

Gastric ulcers were induced in rats by acetic acid. Four days later, animals were treated daily with equivalent acid-inhibiting doses of esomeprazole or famotidine, alone or in combination with indomethacin. At day 3 or 7 of treatment, ulcerated tissues were processed to assess: ulcer area; malondialdehyde; prostaglandin E(2); nuclear factor-kB; proliferating cell nuclear antigen and caspase-3 (Western blot).

RESULTS

In indomethacin-treated animals, esomeprazole was more effective than famotidine or the antioxidant melatonin in promoting ulcer healing. Malondialdehyde levels were increased by indomethacin, and this effect was counteracted by esomeprazole, but not famotidine. Esomeprazole and famotidine, given alone or in combination with indomethacin, increased proliferating cell nuclear antigen expression. Increased levels of prostaglandin E(2) were detected in ulcerated tissues. Ulcer prostaglandin E(2) production was reduced by indomethacin, alone or in combination with esomeprazole or famotidine, while it was enhanced when esomeprazole or famotidine were tested alone. The activation of caspase-3 was induced by indomethacin, and this effect was prevented by esomeprazole, but not famotidine. In the presence of indomethacin, esomeprazole, but not famotidine, enhanced nuclear factor-kB activation in gastric ulcers.

CONCLUSIONS

Esomeprazole counteracts the detrimental action of indomethacin on ulcer repair through both acid-dependent and acid-independent effects. The acid-independent actions are related to decrease in tissue oxidation and apoptosis and to enhancement of nuclear factor-kB activation.

Prevention of nonsteroidal anti-inflammatory drug-induced small-intestinal injury by prostaglandin: a pilot randomized controlled trial evaluated by capsule endoscopy

BACKGROUND

There is no known preventive agent against nonsteroidal anti-inflammatory drug (NSAID) induced small-intestinal injury.

OBJECTIVE

To evaluate by capsule endoscopy whether coadministration of prostaglandin (PG) can prevent small-intestinal damage induced by short-term NSAID treatment.

DESIGN

Single-blind, randomized, controlled trial.

SETTING

All procedures were performed at Nippon Medical School.

SUBJECTS

Thirty-four healthy male volunteers.

METHODS

All subjects were randomly assigned to 2 groups: an NSAID-control group, who underwent NSAID (diclofenac sodium, 25 mg 3 times daily) and omeprazole (20 mg once daily) treatment, and an NSAID-PG group, who received PG (misoprostol, 200 microg 3 times daily) in addition to the same NSAID-omeprazole treatment. Eligible subjects, 15 per group, underwent capsule endoscopy before and 14 days after treatment.

MAIN OUTCOME MEASUREMENTS

The number of mucosal breaks at capsule endoscopy.

RESULTS

NSAID treatment significantly increased the mean (SD) number of mucosal breaks per subject, from a basal level of 0.1 +/- 0.3 up to 2.9 +/- 6.3 lesions in the NSAID-control group (P = .012). In contrast, there was no significant change in the mean number of mucosal breaks before and after PG cotreatment (P = 0.42). Thus, the mean number of posttreatment mucosal breaks per subject was significantly higher in the NSAID-control group than in the NSAID-PG group (P = .028). There was a significant increase in the percentage of subjects in the NSAID-control group, with at least 1 mucosal break after treatment (from 6.7% to 53.3%), whereas there was no change in the incidence of mucosal breaks in the NSAID-PG group, which remained at 13.3%. (P = .002).

LIMITATIONS

Single-center, open-label study.

CONCLUSIONS

PG cotherapy reduced the incidence of small-intestinal lesions induced by a 2-week administration of diclofenac sodium.

Cyclooxygenases: structural and functional insights

Cyclooxygenase (COX; prostaglandin G/H synthase, EC 1.14.99.1) catalyzes the first two steps in the biosynthesis of prostaglandins (PGs). The two COX isoforms COX-1 and COX-2 are the targets of the widely used nonsteroidal anti-inflammatory drugs, indicating a role for these enzymes in pain, fever, inflammation, and tumorigenesis. The ubiquitous constitutive expression of COX-1 and inducible expression of COX-2 have led to the widely held belief that COX-1 produces homeostatic PGs, while PGs produced by COX-2 are primarily pathophysiological. However, recent discoveries call this paradigm into question and reveal as yet underappreciated functions for both enzymes. This review focuses on some of these new insights.

Polyphenols with antiulcerogenic action from aqueous decoction of mango leaves (Mangifera indica L.)

This study was designed to determine the gastroprotective effect of a Mangifera indica leaf decoction (AD), on different experimental models in rodents. The administration of AD up to a dose of 5 g/kg (p.o.) did not produce any signs or symptoms of toxicity in the treated animals, while significantly decreasing the severity of gastric damage induced by several gastroprotective models. Oral pre-treatment with AD (250, 500 or 1000 mg/kg) in mice and rats with gastric lesions induced by HCl/ethanol, absolute ethanol, non-steroidal anti-inflammatory drug (NSAID) or stress-induced gastric lesions resulted in a significant decrease of said lesions. Phytochemical analyses of AD composition demonstrated the presence of bioactive phenolic compounds that represent 57.3% of total phenolic content in this extract. Two main phenolic compounds were isolated, specifically mangiferin (C-glucopyranoside of 1,3,6,7-tetrahydroxyxanthone) and C-glucosyl-benzophenone (3-C-β-D-glucopyranosyl-4’,2,4,6-tetrahydroxybenzophenone). These findings indicate the potential gastroprotective properties of aqueous decoction from M. indica leaves.

COX-1 vs. COX-2 as a determinant of basal tone in the internal anal sphincter

Prostanoids, produced endogenously via cyclooxygenases (COXs), have been implicated in the sustained contraction of different smooth muscles. The two major types of COXs are COX-1 and COX-2. The COX subtype involved in the basal state of the internal anal sphincter (IAS) smooth muscle tone is not known. To identify the COX subtype, we examined the effect of COX-1- and COX-2-selective inhibitors, SC-560 and rofecoxib, respectively, on basal tone in the rat IAS. We also determined the effect of selective deletion of COX-1 and COX-2 genes (COX-1(-/-) and COX-2(-/-) mice) on basal tone in murine IAS. Our data show that SC-560 causes significantly more efficacious and potent concentration-dependent decreases in IAS tone than rofecoxib. In support of these data, significantly higher levels of COX-1 than COX-2 mRNA were found in the IAS. In addition, higher levels of COX-1 mRNA and protein were expressed in rat IAS than rectal smooth muscle. In wild-type mice, IAS tone was decreased 41.4 +/- 3.4% (mean +/- SE) by SC-560 (1 x 10(-5) M) and 5.4 +/- 2.2% by rofecoxib (P < 0.05, n = 5). Basal tone was 0.172 +/- 0.021 mN//mg in the IAS from wild-type mice and significantly less (0.080 +/- 0.015 mN/mg) in the IAS from COX-1(-/-) mice (P < 0.05, n = 5). However, basal tone in COX-2(-/-) mice was not significantly different from that in wild-type mice. We conclude that COX-1-related products contribute significantly to IAS tone.

Effects of pantoprazole on ulcer healing delay associated with NSAID treatment

Nonsteroidal anti-inflammatory drugs delay gastric ulcer healing, and the ability of proton pump inhibitors to counteract this detrimental effect is debated. This study evaluates the effects of pantoprazole on experimental gastric ulcer healing in the presence of indomethacin. Rats with acetic-acid-induced gastric ulcers were orally treated for 3 or 7 days with pantoprazole (15 micromol/kg/day) or famotidine (20 micromol/kg/day), alone or in combination with indomethacin (3 micromol/kg/day). Ulcerated tissues were processed to assess ulcer area, malondialdehyde, proliferating cell nuclear antigen (PCNA) and cleaved caspase-3. Experiments on pylorus-ligated rats indicated that pantoprazole and famotidine were employed at equivalent inhibitory doses on gastric acid secretion (-67.9% and -64.5%, respectively). Indomethacin delayed ulcer healing both at days 3 and 7 (+22 and +35 mm(2) vs control ulcer, respectively). At day 3, pantoprazole was more effective than famotidine in promoting ulcer healing in indomethacin-treated animals (-53.6 and -31.6 mm(2) vs indomethacin, respectively). Malondialdehyde levels and caspase-3 activation in ulcers were increased by indomethacin (+79% and +3.7 folds vs control ulcer, respectively), and these effects were counteracted by pantoprazole (-77.9% and -3.5 folds vs indomethacin, respectively), but not famotidine. Increments of ulcer PCNA expression (+2.5 folds vs normal) were enhanced further by pantoprazole or famotidine, alone or in combination with indomethacin (+8.6 and +10.3 folds vs normal, respectively). Similar results were obtained after 7-day treatments of ulcerated animals with test drugs. It is concluded that, along with acid suppression, pantoprazole exerts acid-independent effects on ulcer healing, which can be ascribed to a decrease in tissue oxidation and apoptosis.