Prostaglandin Deficiency Research Articles

Gastroprotektivne karakteristike krioprezerviranog ekstrakta placente kod kombinovanog delovanja niskih temperatura i inhibicije ciklooksigenaze

Introduction. Non-steroidal anti-inflammatory drugs (NSAIDs) are ranked first among the world's effective anti-inflammatory and analgesic drugs with anticipated side effects. That is why the prevention of development of adverse reactions associated with NSAIDs, in particular, of those related to their ulcerogenicity, remains a serious global problem. Aims. To characterize the mechanisms of gastrocytoprotective activity of cryopreserved placenta in combined action of low temperatures and diclofenac sodium. Material and methods. The study was performed on 42 male rats weighing 200-220 g. Acute diclofenac sodium-induced gastropathy was reproduced by a single injection of the latter in rats at the dose of 50 mg/kg. The content of malonic dialdehyde, catalase activity, prostaglandin synthase activity and the content of nitrogen monoxide metabolites in homogenates of gastric mucosa were determined by spectrophotometric method. Results and discussion. The study showed that prophylactic administration of placental cryoextract in rats with diclofenac sodium-induced gastropathy is associated with increased activity of antioxidant system in gastric mucosa as demonstrated by an elevated catalase activity by 40.0% as compared with control rats. Modulation of antioxidant-prooxidant homeostasis is believed to be one of the principal mechanisms of gastrocytoprotective action in combined action of low temperatures and cryoextract of the placenta. This is shown by a statistically significant (p < 0.05) 2.2-fold increase of antioxidant-prooxidant index in the study group as compared with rats with diclofenac sodium-induced gastropathy. Administration of placental cryoextract was found to increase prostaglandin synthase activity in rats with diclofenac sodium-induced gastropathy by two times as compared with control rats, which would reduce iatrogenic prostaglandin deficiency in gastric mucosa. Also, the combined action of low temperatures and of placenta cryoextract was associated with a statistically significant (p < 0.05) increase in the level of metabolites of nitrogen monoxide (by 70.1%) as compared with rats with diclofenac sodium-induced gastropathy. Conclusions. Modulation of prooxidant-antioxidant homeostasis in gastric mucosa and increase in contents of nitrogen monoxide metabolites and prostaglandin synthase activity are the leading mechanisms of gastroprotective activity of cryopreserved placental extract in diclofenac sodium-induced gastropathy.

Preconditioning Effects of Forced and Voluntary Running on Stress– and Indomethacin–induced Gastric Injury in Rats

Physical activity and, especially, running, is natural stressor which is increasingly recommended as preconditioning for prevention of the number of diseases. Although regular physical activity can be beneficial in the prevention and the management of several diseases, the intensive exercise may promote or exacerbate the gastrointestinal injury. The aim of the study was to investigate preconditioning effects of forced and voluntary running on a vulnerability of the gastric mucosa to ulcerogenic action of cold‐restraint stress (3 h, 10°C) or indomethacin (IM, 35 mg/kg, sc). For forced treadmill (0 incline) running two protocols were used: high‐intensity (25 sm/s, 30 min) and moderate‐intensity (15 sm/s, 15 min) running. For voluntary running the rats were placed in the cages with wheels (2 h/day) during 4 days before experiment. On a Day of experiment preliminary fasted (24 h) rats were subjected forced running in treadmill or voluntary running in the wheel (2 h), then, they were given back in their cages and resting at room temperature for 1 h before the onset of ulcerogenic stimulus. Control animals were in their rcages, but they were also given ulcerogenic stimulus. Stress‐induced and IM‐induced gastric erosions were examined 3 h after the onset of cold‐restraint or 4 h after IM administration, respectively. A single high‐intensity treadmill session attenuated IM‐induced gastric erosions but aggravated stress‐induced gastric erosions. A single moderate‐intensity treadmill session didn’t influence IM or stress‐induced gastric injury, but moderate‐intensity treadmill in training regime (during 4 days before experiment) attenuated stress‐induced gastric erosions. Voluntary wheel running resulted in a decrease of IM‐induced erosions but an increase of stress‐induced gastric injury. The results obtained suggest that moderate‐intensity treadmill running in training regime exerts gastroprotective effect on stress‐induced gastric injury whereas by high‐intensity treadmill running as well as voluntary wheel running has proulcerogenic action in this model. At the same time high‐intensity treadmill as well as voluntary wheel running produced gastroprotective effect on IM‐induced gastric erosions. Thus, preconditioning effect of forced or voluntary running on the gastric injury is dependent on an intensity of treadmill running as well as a nature of ulcerogenic stimulus. We suppose that a significance of the compensatory gastroprotective action of glucocorticoids during IM‐induced prostaglandin deficiency which was demonstrated in our previous studies may explain the gastroprotective effects of the preconditioning in the IM ulcerogenic model.Support or Funding InformationThe study was supported by grant of Russian Science Foundation (RSF) N 19‐15‐00430.

Role of Glucocorticoids in Gastroprotection Induced by Capsaicin

The pivotal role of capsaicin‐sensitive peptidergic sensory fibers in maintaining of gastric mucosal integrity against injurious interventions has been well established in rats and then in human. Clinical finding suggests that capsaicin‐induced gastric mucosal protection against the injurious effects of ethanol or indomethacin is due to the acute stimulatory effect of the compound. It was concluded that patients taking non‐steroidal anti‐inflammatory drugs (NSAID) regularly can decrease the incidence and severity of gastric ulceration, if they have moderate spicy foods. Opposite effect has been observed in rats desensitized by capsaicin. Functional blockade of gastric sensory nerve endings elicited by systemic capsaicin application was resulted in impaired mucosal protection against various ulcerogenic agents. Our previous findings suggest a pivotal compensatory role of glucocorticoids in maintenance of gastric mucosal integrity in rats desensitized by capsaicin. In this study, we tested if glucocorticoids can participate in capsaicin‐caused gastroprotection during NSAID‐caused gastropathy accompanied by prostaglandin deficiency in rats. Gastric injury was induced by indomethacin (IM). A single IM administration (35 mg/kg, sc) into fasting (24 h) rats caused the formation of gastric erosions 4 h after injection. The effects of small doses (0.1, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0 mg/kg, sc) of capsaicin on the blood corticosterone and glucose levels and IM‐induced gastric injury were tested. A single capsaicin administration was performed one hour before IM administration. To test the participation of corticosterone in the gastroprotective effect of capsaicin, the pretreatment by the inhibitor of glucocorticoid synthesis, metyrapone (30 mg/kg, i.p., 30 min before capsaicin) was used. We found that the pretreatment with capsaicin (0.5–10.0 mg/kg, sc) reduced dose dependently the area of IM‐induced erosions. This protection was accompanied by a gradual increase in blood corticosterone and glucose levels. Metyrapone injected shortly before capsaicin administration (1.0 mg/kg) caused a fast inhibition of capsaicin‐induced corticosterone response and reversed the protective effect of capsaicin on the gastric mucosa against the IM‐produced injury. The present study confirms evidence for the powerful gastroprotective potency of capsaicin during NSAID‐caused gastropathy. The findings obtained demonstrate that capsaicin administration resulted in an increase in plasma corticosterone levels which in turn plays a pivotal role in maintaining of gastric mucosal integrity against injurious intervention of IM.Support or Funding InformationThe study was supported by grants of RSF N 19‐15‐00430 (NSAID‐caused gastropathy with prostaglandin deficiency) and RFBR N 19‐015‐00514a (capsaicin‐induced gastroprotection)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Gastroprotective Role of Glucocorticoids During NSAID-induced Gastropathy

Nonsteroidal anti-inflammatory drugs (NSAIDs) make significant contributions to gastric ulcer disease which remains widespread. Although several factors have been postulated as pathogenic elements of the gastric injury induced by NSAIDs, it is, however believed that prostaglandin deficiency plays a critical role in the pathogenesis of this injury. During prostaglandin deficiency, other defensive mechanisms might operate to attenuate NSAID-induced gastropathy. According to our results, NSAIDs, similar to stress, induce an increase in glucocorticoid production that in turn helps the gastric mucosa to resist the harmful actions of these drugs. In this article, we review our experimental data suggesting that glucocorticoids may play a role as natural defensive factors in maintaining the integrity of the gastric mucosa during NSAID therapy and might operate to attenuate NSAID-induced gastropathy.

Su1746 Pathogenesis of Steroid-Induced Gastric Ulceration in Rats: Involvement of Prostaglandin Deficiency, Pepsin Secretion, and Healing Impairment Action

Su1746 Pathogenesis of Steroid-Induced Gastric Ulceration in Rats: Involvement of Prostaglandin Deficiency, Pepsin Secretion, and Healing Impairment Action

Phospholipids and insulin resistance in psychosis: a lipidomics study of twin pairs discordant for schizophrenia.

BackgroundSeveral theories have been proposed to conceptualize the pathological processes inherent to schizophrenia. The 'prostaglandin deficiency' hypothesis postulates that defective enzyme systems converting essential fatty acids to prostaglandins lead to diminished levels of prostaglandins, which in turn affect synaptic transmission.MethodsHere we sought to determine the lipidomic profiles associated with schizophrenia in twin pairs discordant for schizophrenia as well as unaffected twin pairs. The study included serum samples from 19 twin pairs discordant for schizophrenia (mean age 51 ± 10 years; 7 monozygotic pairs; 13 female pairs) and 34 age and gender matched healthy twins as controls. Neurocognitive assessment data and gray matter density measurements taken from high-resolution magnetic resonance images were also obtained. A lipidomics platform using ultra performance liquid chromatography coupled to time-of-flight mass spectrometry was applied for the analysis of serum samples.ResultsIn comparison to their healthy co-twins, the patients had elevated triglycerides and were more insulin resistant. They had diminished lysophosphatidylcholine levels, which associated with decreased cognitive speed.ConclusionsOur findings may be of pathophysiological relevance since lysophosphatidylcholines, byproducts of phospholipase A2-catalyzed phospholipid hydrolysis, are preferred carriers of polyunsaturated fatty acids across the blood-brain barrier. Furthermore, diminishment of lysophosphatidylcholines suggests that subjects at risk of schizophrenia may be more susceptible to infections. Their association with cognitive speed supports the view that altered neurotransmission in schizophrenia may be in part mediated by reactive lipids such as prostaglandins.

Small Intestinal Injury Caused by NSAIDs/Aspirin: Finding New from Old

Small intestinal injury caused by non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin is an epoch making topic in clinical field with the aid of new devices, capsule endoscopy and double balloon enteroscopy to look at small intestine directly. However, the injury has been reported in animals since more than 40 years ago. Proposed mechanisms are impairment of mucosal defense through inhibition of cyclooxygenase (COX) resulting in deficiency of prostaglandins, and mitochondrial disorder. Possible aggressive factors are NSAIDs/aspirin themselves, bile, and enterobacteria. Translocation of enterobacteria through the mucosa impaired integrity may be the first step of the injury. Bacterial lipopolysaccharides stimulate toll-like receptor-4 in macrophages, which increases proinflammatory cytokines through MyD88 signaling pathway. Finally neutrophils are activated and the small intestinal mucosa is injured with the attacks of NSAIDs/aspirin themselves, bile, and proteolytic enzymes and active oxygen species released by neutrophils. Candidates of treatment tools are prostaglandin derivatives, mucoprotective drugs, probiotics, and mitochondrial protective drugs such as metronidazole and cyclosporin A. Further clinical studies are needed to elucidate the effect in humans.

Quality of ulcer healing in gastrointestinal tract: Its pathophysiology and clinical relevance

In this paper, we review the concept of quality of ulcer healing (QOUH) in the gastrointestinal tract and its role in the ulcer recurrence. In the past, peptic ulcer disease (PUD) has been a chronic disease with a cycle of repeated healing/remission and recurrence. The main etiological factor of PUD is Helicobacter pylori (H. pylori), which is also the cause of ulcer recurrence. However, H. pylori-negative ulcers are present in 12%-20% of patients; they also recur and are on occasion intractable. QOUH focuses on the fact that mucosal and submucosal structures within ulcer scars are incompletely regenerated. Within the scars of healed ulcers, regenerated tissue is immature and with distorted architecture, suggesting poor QOUH. The abnormalities in mucosal regeneration can be the basis for ulcer recurrence. Our studies have shown that persistence of macrophages in the regenerated area plays a key role in ulcer recurrence. Our studies in a rat model of ulcer recurrence have indicated that proinflammatory cytokines trigger activation of macrophages, which in turn produce increased amounts of cytokines and chemokines, which attract neutrophils to the regenerated area. Neutrophils release proteolytic enzymes that destroy the tissue, resulting in ulcer recurrence. Another important factor in poor QOUH can be deficiency of endogenous prostaglandins and a deficiency and/or an imbalance of endogenous growth factors. Topically active mucosal protective and antiulcer drugs promote high QOUH and reduce inflammatory cell infiltration in the ulcer scar. In addition to PUD, the concept of QOUH is likely applicable to inflammatory bowel diseases including Crohn's disease and ulcerative colitis.

NSAIDs and Acidic Environment Induce Gastric Mucosal Cellular Mitochondrial Dysfunction

Non-steroidal anti-inflammatory drugs (NSAIDs) often cause gastrointestinal complications such as gastric ulcers and erosions. Recent studies on the pathogenesis have revealed that NSAIDs induce lipid peroxidation in gastric epithelial cells by generating superoxide in mitochondria, independently with cyclooxygenase inhibition and the subsequent prostaglandin deficiency. More recently, gastric hydrochloric acid (HCl) has been regarded as an inciting factor of gastric mucosal injuries, and reportedly induced cellular lipid peroxidation in vitro. We hypothesized that gastric acid and NSAID treatment synergistically induce cellular injury in gastric epithelial cells. We treated gastric epithelial RGM1 cells with acidic solutions and NSAIDs, and examined cellular injury, lipid peroxidation, mitochondrial transmenbrane potential and mitochondrial superoxide. We pretreated RGM1 cells with the acidic solutions for 0.5 h and after that treated them with each NSAID for 15 h and found that the exposure to acid and NSAIDs indeed induced cellular injury. We hypothesized that gastric acid and NSAID treatment synergistically induce mitochondrial superoxide production, which induces gastric cellular injury.

Pathogenesis of NSAID-induced gastric damage: Importance of cyclooxygenase inhibition and gastric hypermotility

This article reviews the pathogenic mechanism of non-steroidal anti-inflammatory drug (NSAID)-induced gastric damage, focusing on the relation between cyclooxygenase (COX) inhibition and various functional events. NSAIDs, such as indomethacin, at a dose that inhibits prostaglandin (PG) production, enhance gastric motility, resulting in an increase in mucosal permeability, neutrophil infiltration and oxyradical production, and eventually producing gastric lesions. These lesions are prevented by pretreatment with PGE₂ and antisecretory drugs, and also via an atropine-sensitive mechanism, not related to antisecretory action. Although neither rofecoxib (a selective COX-2 inhibitor) nor SC-560 (a selective COX-1 inhibitor) alone damages the stomach, the combined administration of these drugs provokes gastric lesions. SC-560, but not rofecoxib, decreases prostaglandin E₂ (PGE₂) production and causes gastric hypermotility and an increase in mucosal permeability. COX-2 mRNA is expressed in the stomach after administration of indomethacin and SC-560 but not rofecoxib. The up-regulation of indomethacin-induced COX-2 expression is prevented by atropine at a dose that inhibits gastric hypermotility. In addition, selective COX-2 inhibitors have deleterious influences on the stomach when COX-2 is overexpressed under various conditions, including adrenalectomy, arthritis, and Helicobacter pylori-infection. In summary, gastric hypermotility plays a primary role in the pathogenesis of NSAID-induced gastric damage, and the response, causally related with PG deficiency due to COX-1 inhibition, occurs prior to other pathogenic events such as increased mucosal permeability; and the ulcerogenic properties of NSAIDs require the inhibition of both COX-1 and COX-2, the inhibition of COX-1 upregulates COX-2 expression in association with gastric hypermotility, and PGs produced by COX-2 counteract the deleterious effect of COX-1 inhibition.

Contribution of Glucocorticoid Hormones to the Gastroprotective Effect of Ischemic Preconditioning in Rats in Normal Conditions and In Prostaglandin Deficiency

Contribution of Glucocorticoid Hormones to the Gastroprotective Effect of Ischemic Preconditioning in Rats in Normal Conditions and In Prostaglandin Deficiency

Gastric Ulcerogenic and Healing Impairment Actions of Alendronate, A Nitrogen- Containing Bisphosphonate - Prophylactic Effects of Rebamipide

Alendronate, a nitrogen containing bisphosphonate (BPP), when given p.o., decreases the transmucosal potential difference by direct irritating action, resulting in non-hemorrhagic lesions in both the corpus and antrum of fasted rats, and after re-feeding produces large ulcers in the antrum with increased vascular permeability and submucosal edema. The pathogenesis of these ulcers may be explained by the impairment of the mucosal anti-oxidative system and does not involve acid digestion as well as a deficiency of prostaglandins (PGs). Alendronate, although does not affect cyclooxygenase/ PGE(2) production in the ulcerated mucosa, but impairs the healing of gastric ulcers in rats, and this effect may be related to the down-regulation of vascular endothelial growth factor and basic fibroblast growth factor (bFGF), the important growth factors for the vascularization/granulation as well as the suppression of the stimulatory action of epidermal growth factor on the epithelial proliferation/migration. Rebamipide, a mucosal protective and antiulcer drug, does not affect the direct irritating action of alendronate in the gastric mucosa but prevents the alendronate-induced antral ulceration, probably due to anti-oxidative and anti-inflammatory actions. In addition, this agent also antagonizes the healing impairment action of alendronate by counteracting the down-regulation of bFGF expression in the ulcerated mucosa. It is assumed that rebamipide is a promising drug that can be used as a prophylactic against the adverse effects of BPPs in the stomach.

The pathophysiology of non-steroidal anti-inflammatory drug (NSAID)-induced mucosal injuries in stomach and small intestine

Non-steroidal anti-inflammatory drugs are the most commonly prescribed drugs for arthritis, inflammation, and cardiovascular protection. However, they cause gastrointestinal complications. The pathophysiology of these complications has mostly been ascribed to non-steroidal anti-inflammatory drugs’ action on the cyclooxygenase inhibition and the subsequent prostaglandin deficiency. However, recent clinical demonstrated the prevalence of non-steroidal anti-inflammatory drugs-induced small intestinal mucosal injury is more often than previously expected. In this review, we discuss the defense mechanisms of stomach, and the pathophysiology of non-steroidal anti-inflammatory drugs-induced injury of stomach and small intestine, especially focused on non-steroidal anti-inflammatory drugs’ action on mitochondria.

Eicosanoid Lipid Mediators in Fibrotic Lung Diseases: Ready for Prime Time?

Recognition of a pivotal role for eicosanoids in both normal and pathologic fibroproliferation is long overdue. These lipid mediators have the ability to regulate all cell types and nearly all pathways relevant to fibrotic lung disorders. Abnormal fibroproliferation is characterized by an excess of profibrotic leukotrienes and a deficiency of antifibrotic prostaglandins. The relevance of an eicosanoid imbalance is pertinent to diseases involving the parenchymal, airway, and vascular compartments of the lung, and is supported by studies conducted both in humans and animal models. Given the lack of effective alternatives, and the existing and emerging options for therapeutic targeting of eicosanoids, such treatments are ready for prime time.

Cellular membrane fluidity measurement by fluorescence polarization in indomethacin-induced gastric cellular injury in vitro

Gastric complications of indomethacin involve generation of reactive oxygen species, which induce gastric mucosal injury via lipid peroxidation of cell membranes. Peroxidation by reactive oxygen species alters the amounts of unsaturated fatty acids in the cell membrane and thus affects membrane fluidity. Indomethacin-induced lipid peroxidation can thus be detected by measuring cellular membrane fluidity by the fluorescence polarization (FP) method. The aim of this study was to elucidate the usefulness of the FP method for detecting indomethacin-induced gastric cellular injury in RGM-1 cells. Indomethacin-treated RGM-1 cells were investigated by conventional cytotoxicity assay, fluorometry of diphenyl-1-pyrenylphosphine (DPPP) to detect lipid peroxidation, and FP. The effects of both a radical scavenger and an initiator on membrane fluidity change (MFC) in RGM-1 cells were examined. The sensitivity of FP in detecting cellular injury was compared with those of DPPP fluorometry and conventional cytotoxicity measurements. Indomethacin caused an increase in MFC as determined by FP before cytotoxicity was detected by conventional methods. The increase in MFC was associated with increased membrane phospholipid peroxidation (MPP) but not with a prostaglandin deficiency, and the increases in both MFC and MPP were prevented by vitamin E. The FP method is potentially useful for detecting cellular injury in vitro.

Compensatory gastroprotective role of glucocorticoid hormones during inhibition of prostaglandin and nitric oxide production and desensitization of capsaicin-sensitive sensory neurons

Glucocorticoid hormones produced in response to various ulcerogenic stimuli contribute to the maintenance of the gastric mucosal integrity. The role of glucocorticoids in gastroprotection becomes especially important where there is deficiency of prostaglandins (PGs) or nitric oxide (NO) or desensitization of capsaicin-sensitive sensory neurons (CSN). It has been found that neither inhibition of PG or NO production nor desensitization of CSN by itself provokes damage in the gastric mucosa of rats with normal corticosterone levels. However, each of these treatments results in mucosal damage in adrenalectomized rats; this effect being prevented by corticosterone replacement. Indomethacin-induced gastric erosions are potentiated to similar degrees by adrenalectomy, inhibition of NO production or desensitization of CSN. The potentiation caused by inhibition of NO production or CSN desensitization is further enhanced by concomitant glucocorticoid deficiency. These results suggest a pivotal compensatory role of glucocorticoids in the maintenance of the gastric mucosal integrity under the adverse conditions where the gastroprotective mechanisms provided by PGs, NO and capsaicin-sensitive sensory neurons are impaired.

Dexamethasone Damages the Rat Stomach but Not Small Intestine During Inhibition of COX-1

We previously reported that inhibition of both COX-1 and COX-2 is required for the gastrointestinal ulcerogenic properties of nonsteroidal anti-inflammatory drugs (NSAIDs). Inhibition of COX-1 up-regulates COX-2 expression, and the prostaglandins (PGs) produced by COX-2 help to maintain the mucosal integrity during inhibition of COX-1. In the present study we investigated whether dexamethasone damages rat gastrointestinal mucosa during inhibition of COX-1 and further developed the idea that COX-2 expression is a key event in the ulcerogenic actions of NSAIDs. Dexamethasone was given p.o. in the absence or presence of SC-560 (a selective COX-1 inhibitor), and the stomach or intestine was examined 8 or 24 hr later, respectively. Neither dexamethasone nor SC-560 alone damaged the gastrointestinal mucosa. In the presence of SC-560, however, dexamethasone damaged the stomach but not small intestine. SC-560 decreased PGE(2) levels in both tissues, with a gradual recovery accompanying the up-regulation of COX-2 expression, and both the recovery of PGE(2) levels and the expression of COX-2 were inhibited by dexamethasone. In the animals treated with SC-560, iNOS expression was up-regulated in the intestinal but not the gastric mucosa, and this response was also inhibited by dexamethasone. These results suggest a risk from steroid therapy in the stomach when COX-2 expression is up-regulated. Dexamethasone does not provoke damage in the intestine, despite inhibiting the up-regulation of COX-2 expression under conditions of PG deficiency; at least one of the reasons is that this agent prevents the expression of iNOS, a major factor in the pathogenesis of intestinal lesions.

Development of intestinal, but not gastric damage caused by a low dose of indomethacin in the presence of rofecoxib

The ulcerogenic effect of rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, on the gastrointestinal mucosa was investigated in the presence of a low dose of indomethacin. Indomethacin at 3 mg/kg did not cause any damage in both the stomach and small intestine, despite inhibiting prostaglandin (PG) production. Rofecoxib had no effect on PG production and did not cause any damage in these tissues. In the presence of indomethacin, however, rofecoxib provoked damage in the small intestine but not the stomach. Indomethacin at 3 mg/kg induced hypermotility and COX-2 expression in the intestine but not in the stomach, both in an atropine-sensitive manner. These results suggest that a low dose of indomethacin produces damage in the small intestine but not in the stomach when administered together with rofecoxib. The PG deficiency caused by a low dose of indomethacin produces hypermotility and COX-2 expression in the small intestine, and results in damage when COX-2 is inhibited. It is assumed that the hypermotility response is a key event in the expression of COX-2 and thereby important in the development of mucosal damage in the gastrointestinal tract.

Gastroprotective action of glucocorticoid hormones during NSAID treatment

In this article we present an overview of the results of our studies suggesting that endogenous glucocorticoid hormones play a role as natural defensive factors in maintaining the integrity of the gastric mucosa during treatment with non-steroidal anti-inflammatory drugs (NSAIDs). In-domethacin and aspirin at ulcerogenic doses induce a rise in corticosterone, which helps the gastric mucosa to resist the harmful actions of these ulcerogenic agents. The gastroprotective action of glucocorticoids during NSAID treatment may be mediated by multiple actions, including maintenance of glucose homeostasis, mucus production and attenuation of enhanced gastric motility and microvascular permeability. According to our findings, glucocorticoid hormones also participate in the healing processes of NSAID-induced gastric injury. It was demonstrated that there is some cooperative interaction between glucocorticoids and prostaglandins (PGs) in gastroprotection, in a way that a deficiency of one protective factor can lead to an apparently compensatory increase of the other. The gastric mucosa becomes more susceptible to injury during deficiency of both glucocorticoids and PGs.

Rofecoxib Produces Intestinal but Not Gastric Damage in the Presence of a Low Dose of Indomethacin in Rats

Indomethacin in small doses is known to inhibit prostaglandin (PG) production, yet it does not damage the gastrointestinal mucosa. We examined whether a cyclooxygenase (COX)-2 inhibitor induces gastrointestinal damage in the presence of a low dose of indomethacin and investigated the ulcerogenic mechanism in relation to COX-2 expression. Rats with or without 18-h fasting were administered rofecoxib (a selective COX-2 inhibitor; 10 or 30 mg/kg p.o.) in the absence or presence of indomethacin (3 mg/kg p.o.), and the gastric or intestinal mucosa was examined 8 and 24 h later, respectively. Neither indomethacin nor rofecoxib alone caused damage in the stomach or small intestine. However, indomethacin damaged the small intestine in the presence of rofecoxib, yet the same treatment did not damage the stomach. Indomethacin reduced the mucosal PGE2 content in both tissues, whereas rofecoxib did not. The COX-2 mRNA was up-regulated in the intestine but not the stomach after indomethacin treatment, and the reduced PGE2 content was significantly recovered later only in the small intestine, in a rofecoxib-inhibitable manner. Indomethacin produced hypermotility in the small intestine but not the stomach, whereas rofecoxib had no effect. These results suggest that the PG deficiency caused by a low dose of indomethacin produces hypermotility and COX-2 expression in the small intestine but not the stomach, resulting in damage when COX-2 is inhibited. It is assumed that the hypermotility response is a key event in the expression of COX-2 and thereby important in the development of mucosal damage in the gastrointestinal tract.