NSAID-induced Intestinal Injury Research Articles

Resveratrol attenuates non-steroidal anti-inflammatory drug-induced intestinal injury in rats in a high-altitude hypoxic environment by modulating the TLR4/NFκB/IκB pathway and gut microbiota composition.

Non-steroidal anti-inflammatory drugs (NSAIDs) are currently the most widely used anti-inflammatory medications, but their long-term use can cause damage to the gastrointestinal tract(GIT). One of the risk factors for GIT injury is exposure to a high-altitude hypoxic environment, which can lead to damage to the intestinal mucosal barrier. Taking NSAIDs in a high-altitude hypoxic environment can exacerbate GIT injury and impact gut microbiota. The aim of this study is to investigate the mechanisms by which resveratrol (RSV) intervention alleviates NSAID-induced intestinal injury in a high-altitude hypoxic environment, as well as its role in regulating gut microbiota. Aspirin was administered orally to rats to construct a rat model of intestinal injury induced by NSAIDs. Following the induction of intestinal injury, rats were administered RSV by gavage, and the expression levels of TLR4, NF-κB,IκB as well as Zonula Occludens-1 (ZO-1) and Occludin proteins in the different treatment groups were assessed via Western blot. Furthermore, the expression of the inflammatory factors IL-10, IL-1β, and TNF-α was evaluated using Elisa.16sRNA sequencing was employed to investigate alterations in the gut microbiota. The HCk group showed elevated expression of TLR4/NF-κB/IκB pathway proteins, increased expression of pro-inflammatory factors IL-1β and TNF-α, decreased expression of the anti-inflammatory factor IL-10, and expression of intestinal mucosal barrier proteins ZO-1 and Occludin. The administration of NSAIDs drugs in the plateau hypoxic environment exacerbates intestinal inflammation and damage to the intestinal mucosal barrier. After treatment with RSV intervention, the expression of TLR4/NF-κB/IκB signaling pathway proteins would be reduced, thereby lowering the expression of inflammatory factors in the HAsp group. The results of HE staining directly show the damage to the intestines and the repair of intestinal mucosa after RSV intervention. 16sRNA sequencing results show significant differences (P<0.05) in Ruminococcus, Facklamia, Parasutterella, Jeotgalicoccus, Coprococcus, and Psychrobacter between the HCk group and the Ck group. Compared to the HCk group, the HAsp group shows significant differences (P<0.05) in Facklamia, Jeotgalicoccus, Roseburia, Psychrobacter, and Alloprevotella. After RSV intervention, Clostridium_sensu_stricto bacteria significantly increase compared to the HAsp group. Resveratrol can attenuate intestinal damage caused by the administration of NSAIDs at high altitude in hypoxic environments by modulating the TLR4/NF-κB/IκB signaling pathway and gut microbiota composition.

Wheat peptides inhibit the activation of MAPK and NF-κB inflammatory pathways and maintain epithelial barrier integrity in NSAID-induced intestinal epithelial injury.

The use of non-steroidal anti-inflammatory drugs (NSAIDs) has negative effects on the gastrointestinal tract, but the proton pump inhibitors currently in use only protect against gastrointestinal disease and may even make NSAID-induced enteropathy worse. Therefore, new approaches to treating enteropathy are required. This study aimed to investigate the protective effect of wheat peptides (WPs) against NSAID-induced intestinal damage in mice and their mechanism. Here, an in vivo mouse model was built to investigate the protective and reparative effects of different concentrations of WPs on NSAID-induced intestinal injury. WPs ameliorated NSAID-induced weight loss and small intestinal tissue damage in mice. WP treatment inhibited NSAID-induced injury leading to increased levels of oxidative stress and expression levels of inflammatory factors. WPs protected and repaired the integrity and permeability injury of the intestinal tight junction induced by NSAIDs. An in vitro Caco-2 cell model was built with lipopolysaccharide (LPS). WP pretreatment inhibited LPS-induced changes in the Caco-2 cell permeability and elevated the levels of oxidative stress. WPs inhibited LPS-induced phosphorylation of NF-κB p65 and mitogen-activated protein kinase (MAPK) signaling pathways and reduced the expression of inflammatory factors. In addition, WPs increased tight junction protein expression, which contributed to improved intestinal epithelial dysfunction. Our results suggest that WPs can ameliorate NSAID-induced impairment of intestinal barrier functional integrity by improving intestinal oxidative stress levels and reducing inflammatory factor expression through inhibition of NF-κB p65 and MAPK signaling pathway activation. WPs can therefore be used as potential dietary supplements to reduce NSAID-induced injury of the intestine.

The influence of different proton pump inhibitors and potassium-competitive acid blockers on indomethacin-induced small intestinal injury.

The influence of gastric acid inhibitors (GAIs) on nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is controversial. Herein, the influences of different GAIs on NSAID-induced intestinal injury and the underlying mechanisms are clarified. Indomethacin (IND; 10mg/kg/day) was administered to mice to induce small intestinal injury. Disease activity was examined macroscopically and histologically. The permeability of small intestine was evaluated by measuring plasma lipopolysaccharide levels. 16S rDNA sequencing was performed to determine the composition of intestinal flora. Among the four GAIs, ilaprazole (IPZ) significantly attenuated IND-induced small intestinal injury and maintained the integrity of the mucosal barrier. Omeprazole (OPZ) and vonoprazan (VPZ) ameliorated ulceration without significant differences, while rabeprazole (RPZ) failed to protect against the injury. To explore the potential mechanism, we investigated changes in the gut microbiota mediated by GAIs. After 5-day administration, GAIs significantly altered the composition of the gut microbiota. The IND group had a significant decrease in alpha diversity compared with the control group, and this decrease was reversed by OPZ and IPZ treatment, respectively. After IPZ treatment, the community membership was more assembled in the control group than the IND group. Further, we found that Lactobacillus was significantly increased in the groups of OPZ, IPZ, and VPZ, while Bacteroides was significantly increased in the RPZ group. Our results indicated that GAIs have different influences on the mucosal barrier, possibly by altering the composition of intestinal microbiota, and the impacts mediated by various GAIs in the IND-induced intestinal damage model seem different.

Fecal 16S rRNA Gene Sequencing Analysis of Changes in the Gut Microbiota of Rats with Low-Dose Aspirin-Related Intestinal Injury.

Background The incidence of small intestinal injury caused by low-dose aspirin (LDA) is high, but the pathogenesis and intervention measures of it have not been elucidated. Recent studies have found gut microbiota to be closely associated with onset and development of NSAID-induced intestinal injury. However, studies of the changes in the gut microbiota of rats with LDA-related intestinal injury have been lacking recently. In this study, we investigated fecal 16S rRNA gene sequencing analysis of changes in the gut microbiota of rats with LDA-related intestinal injury. Methods Sprague-Dawley (SD) rat models of small intestinal injury were established by intragastric administration of LDA. The small intestinal tissues and the fecal samples were harvested. The fecal samples were then analyzed using high-throughput sequencing of 16S rRNA V3-V4 amplicons. The gut microbiota composition and diversity were analyzed and compared using principal coordinate analysis (PCoA), nonmetric multidimensional scaling (NMDS) analysis, the unweighted pair-group method with arithmetic mean (UPGMA) clustering analysis, multivariate statistical analysis (ANOSIM, MetaStats, and LEfSe), and spatial statistics. Results The LDA rat model was successfully established. Decreased Firmicutes and increased Bacteroidetes abundances in rats with LDA-induced small intestinal injury were revealed. MetaStats analysis between the before administration of LDA (CG) and after administration of LDA (APC) groups showed that the intestinal floras exhibiting significant differences (P < 0.05, q < 0.1) were Firmicutes, Bacteroides, Cyanobacteria, Melainabacteria, Coriobacteriia, Bacteroidia, Bacteroidales, Eubacteriaceae, and Streptococcaceae. In addition, the bacterial taxa showing significant differences between the control (NS) and APC groups were Firmicutes, Bacteroides, Verrucomicrobiaceae and Peptococcaceae. Conclusions The alterations in the gut microbiota composition and diversity of rats with LDA-related intestinal injury were found in the present study. The change of gut microbiota in LDA-related intestinal injury will lay the foundation for further research on the function and signaling pathways of the intestinal flora and promote the use of intestinal flora as drug targets to treat LDA-induced small intestinal injury.

Histamine H2-Receptor Antagonists Improve Non-Steroidal Anti-Inflammatory Drug-Induced Intestinal Dysbiosis

Dysbiosis, an imbalance of intestinal flora, can cause serious conditions such as obesity, cancer, and psychoneurological disorders. One cause of dysbiosis is inflammation. Ulcerative enteritis is a side effect of non-steroidal anti-inflammatory drugs (NSAIDs). To counteract this side effect, we proposed the concurrent use of histamine H2 receptor antagonists (H2RA), and we examined the effect on the intestinal flora. We generated a murine model of NSAID-induced intestinal mucosal injury, and we administered oral H2RA to the mice. We collected stool samples, compared the composition of intestinal flora using terminal restriction fragment length polymorphism, and performed organic acid analysis using high-performance liquid chromatography. The intestinal flora analysis revealed that NSAID [indomethacin (IDM)] administration increased Erysipelotrichaceae and decreased Clostridiales but that both had improved with the concurrent administration of H2RA. Fecal levels of acetic, propionic, and n-butyric acids increased with IDM administration and decreased with the concurrent administration of H2RA. Although in NSAID-induced gastroenteritis the proportion of intestinal microorganisms changes, leading to the deterioration of the intestinal environment, concurrent administration of H2RA can normalize the intestinal flora.

A Rapid Screenable Assay for Compounds That Protect Against Intestinal Injury in Zebrafish Larva.

This chapter describes a method to assay compounds modulating NSAID-induced intestinal injury in zebrafish larvae. The assay employs the NSAID glafenine, which causes intestinal epithelial cell damage and death by inducing organelle stress responses (endoplasmic reticulum and mitochondrial) and blocking the unfolded protein response pathway. This epithelial damage includes sloughing of intestinal cells into the lumen and out the cloaca of the zebrafish larvae. Exposing larvae to acridine orange highlights this injury when visualized under fluorescence microscope; injured fish develop intensely red-staining intestines, as well as a "tube" or cord of red color extending through the intestine and out the cloaca. Using this rapid visually screenable method, various candidate compounds were successfully tested for their ability to prevent glafenine-induced intestinal injury. Because this assay involves examination of larval zebrafish intestinal pathology, we have also included our protocol for preparation and analysis of zebrafish histology. The protocol includes numerous steps to generate high-quality zebrafish histology slides, as well as protocols to establish accurate anatomic localization of any given tissue cross-section-processes that are made technically difficult by the small size of zebrafish larvae.

Autophagy Deficiency Diminishes Indomethacin-Induced Intestinal Epithelial Cell Damage through Activation of the ERK/Nrf2/HO-1 Pathway.

Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause epithelial cell damage in the stomach, intestine, and colon. NSAIDs are reported to induce autophagy and apoptosis in intestinal epithelial cells; however, their role in cell damage is poorly understood. To examine the role of autophagy in cell damage, we used autophagy-related gene Atg5-conditional knockout mice, in which the Atg5 gene is only knocked out in intestinal epithelial cells. In an indomethacin (IM)-induced gastrointestinal ulcer mouse model, intestinal epithelium damage was reduced in Atg5-conditional knockout mice compared with wild-type mice. IM-induced damage in IEC6 rat intestinal epithelial cells was reduced when Atg5 was silenced (IEC6shAtg5 cells). Western blot analyses indicated that IM-induced apoptosis decreased, and the potent, oxidative stress-related extracellular signal-regulated kinase (ERK)/nuclear factor-erythroid2-like2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway was upregulated in IEC6shAtg5 cells. An experiment using a reactive oxygen species (ROS)-sensitive fluorescent dye in IEC6shAtg5 cells revealed that the amount of ROS at the baseline and the rate of increase after IM treatment were lower than in intact IEC6 cells. The mitochondrial membrane potential at the baseline and the reduction rate in IM-treated IEC6shAtg5 cells were lower than in intact IEC6 cells, indicating that autophagy deficiency increased ROS production caused by mitochondrial disturbance. Furthermore, MnTMPyP, a manganese-superoxide dismutase mimetic, significantly inhibited IM-induced autophagy and subsequent apoptosis as well as activation of the ERK/Nrf2/HO-1 pathway. These data suggest that autophagy deficiency and subsequent activation of the ERK/Nrf2/HO-1 pathway diminished IM-induced, apoptosis-mediated intestinal epithelial cell damage, and genetic analyses of single nucleotide polymorphisms in autophagy-related genes could predict NSAID-induced intestinal injury.

Tu1230 Comparative Proteome Analysis of Indomethacin-Treated Intestinal Cells Reveals Down-Regulation of Collagen I in NSAID-Induced Intestinal Injury

Background: Small intestinal lesions induced by NSAIDs are of great concern in clinical settings. Various hypotheses, mainly of which related to the inhibition of prostaglandin synthesis, have been proposed for the origin of these inflammatory responses, however, the precise mechanism is yet to be known. The cellular process of the lesions must involve upand down-regulations of a large number of proteins and complex interactions between them. To elucidate it, global and systematic identification of the proteins in intestinal cells affected by non-steroidal anti-inflammatory drugs (NSAIDs) is essential. Two-dimensional polyacrylamide gel electrophoresis allows the analysis of total proteins from both cells and tissues, so it can help to elucidate the complex interactions and mechanisms inside cells. Aims: To identify the proteins that play a critical role in NSAIDs toxicity in intestinal cells and to clarify the mechanism of intestinal mucosal injuries induced by NSAIDs. Materials and Methods: We performed 2-DE on IEC-6 rat normal intestinal cells that were treated with indomethacin (200 μΜ, 24 h) or a vehicle control. The differentially displayed proteins were identified through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Results: We found 18 up-regulated and 8 down-regulated proteins that showed a statistically significant difference of p < 0.05 and a ≥1.5 average fold difference in spot volume as a result of indomethacin treatment. Among these, we found that collagen I and the proteins involved in collagen I synthesis and maturation were all down-regulated. Consistent with this, immunohistochemical analysis showed that the indomethacin-treated rat intestinal mucosal cells exhibits decreased collagen I expression on its apical surface. Furthermore, the cell-protective effect of collagen I on intestinal mucosal cells was demonstrated by the use of a collagen-synthesis inhibitor and cell cultivation on collagen-coated plates versus uncoated plates. Conclusions: For the first time in the literature, a proteomic approach was employed to identify the global proteome alterations of the intestinal mucosa using indomethacin-treated and untreated IEC-6 cells. These results show that collagen I may play an important role in cytoprotection against indomethacin-induced intestinal mucosal injury. Insights gained from the current study may facilitate the development of new therapeutic strategies against NSAID-induced intestinal injury.

Tu1232 Expressions of CYP3A and P-Glycoprotein Were Decreased in the Secondary Inflammatory Response of Dextran Sodium Sulfate-Induced Mice Colitis and Its Contribution to the Blood Concentration of Cyclosporine A

Background: Small intestinal lesions induced by NSAIDs are of great concern in clinical settings. Various hypotheses, mainly of which related to the inhibition of prostaglandin synthesis, have been proposed for the origin of these inflammatory responses, however, the precise mechanism is yet to be known. The cellular process of the lesions must involve upand down-regulations of a large number of proteins and complex interactions between them. To elucidate it, global and systematic identification of the proteins in intestinal cells affected by non-steroidal anti-inflammatory drugs (NSAIDs) is essential. Two-dimensional polyacrylamide gel electrophoresis allows the analysis of total proteins from both cells and tissues, so it can help to elucidate the complex interactions and mechanisms inside cells. Aims: To identify the proteins that play a critical role in NSAIDs toxicity in intestinal cells and to clarify the mechanism of intestinal mucosal injuries induced by NSAIDs. Materials and Methods: We performed 2-DE on IEC-6 rat normal intestinal cells that were treated with indomethacin (200 μΜ, 24 h) or a vehicle control. The differentially displayed proteins were identified through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Results: We found 18 up-regulated and 8 down-regulated proteins that showed a statistically significant difference of p < 0.05 and a ≥1.5 average fold difference in spot volume as a result of indomethacin treatment. Among these, we found that collagen I and the proteins involved in collagen I synthesis and maturation were all down-regulated. Consistent with this, immunohistochemical analysis showed that the indomethacin-treated rat intestinal mucosal cells exhibits decreased collagen I expression on its apical surface. Furthermore, the cell-protective effect of collagen I on intestinal mucosal cells was demonstrated by the use of a collagen-synthesis inhibitor and cell cultivation on collagen-coated plates versus uncoated plates. Conclusions: For the first time in the literature, a proteomic approach was employed to identify the global proteome alterations of the intestinal mucosa using indomethacin-treated and untreated IEC-6 cells. These results show that collagen I may play an important role in cytoprotection against indomethacin-induced intestinal mucosal injury. Insights gained from the current study may facilitate the development of new therapeutic strategies against NSAID-induced intestinal injury.

Tu1234 Effects of the Dipeptidyl Peptidase-4 Inhibitor, Sitagliptin, on Indomethacin-Induced Intestinal Mucosal Injury in a Model of Type 2 Diabetes

Background: Small intestinal lesions induced by NSAIDs are of great concern in clinical settings. Various hypotheses, mainly of which related to the inhibition of prostaglandin synthesis, have been proposed for the origin of these inflammatory responses, however, the precise mechanism is yet to be known. The cellular process of the lesions must involve upand down-regulations of a large number of proteins and complex interactions between them. To elucidate it, global and systematic identification of the proteins in intestinal cells affected by non-steroidal anti-inflammatory drugs (NSAIDs) is essential. Two-dimensional polyacrylamide gel electrophoresis allows the analysis of total proteins from both cells and tissues, so it can help to elucidate the complex interactions and mechanisms inside cells. Aims: To identify the proteins that play a critical role in NSAIDs toxicity in intestinal cells and to clarify the mechanism of intestinal mucosal injuries induced by NSAIDs. Materials and Methods: We performed 2-DE on IEC-6 rat normal intestinal cells that were treated with indomethacin (200 μΜ, 24 h) or a vehicle control. The differentially displayed proteins were identified through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Results: We found 18 up-regulated and 8 down-regulated proteins that showed a statistically significant difference of p < 0.05 and a ≥1.5 average fold difference in spot volume as a result of indomethacin treatment. Among these, we found that collagen I and the proteins involved in collagen I synthesis and maturation were all down-regulated. Consistent with this, immunohistochemical analysis showed that the indomethacin-treated rat intestinal mucosal cells exhibits decreased collagen I expression on its apical surface. Furthermore, the cell-protective effect of collagen I on intestinal mucosal cells was demonstrated by the use of a collagen-synthesis inhibitor and cell cultivation on collagen-coated plates versus uncoated plates. Conclusions: For the first time in the literature, a proteomic approach was employed to identify the global proteome alterations of the intestinal mucosa using indomethacin-treated and untreated IEC-6 cells. These results show that collagen I may play an important role in cytoprotection against indomethacin-induced intestinal mucosal injury. Insights gained from the current study may facilitate the development of new therapeutic strategies against NSAID-induced intestinal injury.

Tu1231 Inhibition of RAC-1 Ameliorates Dextran Sodium Sulfate-Induced Colitis in Mice

Background: Small intestinal lesions induced by NSAIDs are of great concern in clinical settings. Various hypotheses, mainly of which related to the inhibition of prostaglandin synthesis, have been proposed for the origin of these inflammatory responses, however, the precise mechanism is yet to be known. The cellular process of the lesions must involve upand down-regulations of a large number of proteins and complex interactions between them. To elucidate it, global and systematic identification of the proteins in intestinal cells affected by non-steroidal anti-inflammatory drugs (NSAIDs) is essential. Two-dimensional polyacrylamide gel electrophoresis allows the analysis of total proteins from both cells and tissues, so it can help to elucidate the complex interactions and mechanisms inside cells. Aims: To identify the proteins that play a critical role in NSAIDs toxicity in intestinal cells and to clarify the mechanism of intestinal mucosal injuries induced by NSAIDs. Materials and Methods: We performed 2-DE on IEC-6 rat normal intestinal cells that were treated with indomethacin (200 μΜ, 24 h) or a vehicle control. The differentially displayed proteins were identified through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Results: We found 18 up-regulated and 8 down-regulated proteins that showed a statistically significant difference of p < 0.05 and a ≥1.5 average fold difference in spot volume as a result of indomethacin treatment. Among these, we found that collagen I and the proteins involved in collagen I synthesis and maturation were all down-regulated. Consistent with this, immunohistochemical analysis showed that the indomethacin-treated rat intestinal mucosal cells exhibits decreased collagen I expression on its apical surface. Furthermore, the cell-protective effect of collagen I on intestinal mucosal cells was demonstrated by the use of a collagen-synthesis inhibitor and cell cultivation on collagen-coated plates versus uncoated plates. Conclusions: For the first time in the literature, a proteomic approach was employed to identify the global proteome alterations of the intestinal mucosa using indomethacin-treated and untreated IEC-6 cells. These results show that collagen I may play an important role in cytoprotection against indomethacin-induced intestinal mucosal injury. Insights gained from the current study may facilitate the development of new therapeutic strategies against NSAID-induced intestinal injury.

GPR43 activation with COX inhibition induces duodenal injury via 5‐HT pathway (905.1)

The reason why NSAIDs injure the small intestinal mucosa, but spare the duodenal mucosa is unknown. The short‐chain fatty acid receptor GRP43 is expressed in 5‐HT containing enterochromaffin cells, and a selective GPR43 agonist phenylacetamide‐1 (PA1) increases duodenal HCO3‐ secretion (DBS) via 5HT4 receptor activation. We hypothesized that GPR43 activation modulates duodenal mucosal defenses via 5‐HT release in an NSAID‐induced intestinal injury model.We measured DBS with pH and CO2 electrodes in vivo through a duodenal loop, perfused with PA1 (0.1 ‐ 10 µM) while measuring released 5‐HT in the portal vein (PV). Intestinal injury was induced by indomethacin (IND, 10 mg/kg, sc) with or without PA1 (0.1 ‐ 1 mg/kg, ig), the 5HT3 antagonist ondansetron (Ond, 3 mg/kg, ip), omeprazole (OPZ, 10 mg/kg, ig), or atropine (10 mg/kg, ig).Luminal perfusion with PA1 dose‐dependently increased DBS accompanied by 5‐HT release into PV. IND induced small intestinal ulcers with duodenal sparing. PA1 + IND dose‐dependently induced duodenal lesions, whereas PA1 alone had no effect. PA1 + IND‐induced duodenal lesions were inhibited by Ond or OPZ, but not by atropine. Non‐duodenal intestinal lesions were reduced by Ond or atropine, but not by OPZ as previously reported.These results suggest that although GPR43 activation enhances mucosal defenses by increased DBS via 5HT4 activation, GPR43 activation combined with COX inhibition may increase the vulnerability of the duodenal mucosa to gastric acid via 5HT3 activation.Grant Funding Source: Supported by VA Merit Review, NIH R01 DK54221

Preventive effect of agaro‐oligosaccharides on non‐steroidal anti‐inflammatory drug‐induced small intestinal injury in mice

Non-steroidal anti-inflammatory drugs (NSAIDs), which are commonly used in clinical medicine, cause erosion, ulcers, and bleeding in the gastrointestinal tract. No effective agent for the prevention and treatment of small intestinal injury by NSAIDs has been established. This study investigates the effects of agaro-oligosaccharides (AGOs) on NSAID-induced small intestinal injury in mice. Mice were treated with indomethacin, an NSAID, to induce intestinal injury. The respective degrees of mucosal injury of mice that received AGO and control mice were compared. Heme oxygenase-1 (HO-1) expression using quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemistry were measured. The expression of keratinocyte chemoattractant (KC) was measured using qRT-PCR and enzyme-linked immunosorbent assay. AGO administration induced HO-1 expression in mouse small intestinal mucosa. Induction was observed mainly in F4/80 positive macrophages. The increased ulcers score, myeloperoxidase activity, and KC expression by indomethacin were inhibited by AGO administration. Conversely, HO inhibitor cancelled AGO-mediated prevention of intestinal injury. In mouse peritoneal macrophages, AGOs enhanced HO-1 expression and suppressed lipopolysaccharide-induced KC expression. Furthermore, AGOs enhanced the expressions of alternatively activated macrophage markers arginase-1, mannose receptor-1, and chitinase 3-like 3. Results suggest that oral administration of AGOs prevents NSAID-induced intestinal injury.

Su1762 Ursodeoxycholic Acid (URSO) May Be Protective Against NSAID-Induced Intestinal Injury

Su1762 Ursodeoxycholic Acid (URSO) May Be Protective Against NSAID-Induced Intestinal Injury

Non-Steroidal Anti-Inflammatory Drug-Induced Enteropathy

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed drugs in the world. NSAID-induced lower gastrointestinal (GI) complications are increasing while upper GI complications are decreasing. Lower GI events accounted for 40% of all serious GI events in patients on NSAIDs. Capsule endoscopy and device assisted enteroscopy are available for detection of small intestinal lesions. Capsule endoscopy studies have demonstrated that NSAIDs use in healthy volunteers raised the incidence (55% to 75%) of intestinal damage. It appears that selective cyclooxygenase-2 inhibitors (coxibs) improved upper and lower GI safety based on results of clinical trials. Selective coxibs are still capable of triggering GI adverse events and cardiovascular toxicity issues were the main focus of concerns. Unfortunately, definite strategies are not available to prevent or heal NSAID-induced intestinal injuries. Thus, there is still a strong clinical need for effective drugs with improved safety profiles than the existing NSAIDs.

Zebrafish glafenine-intestinal injury is ameliorated by mu-opioid signaling via enhancement of Atf6-dependent cellular stress responses

SUMMARYBeside their analgesic properties, opiates exert beneficial effects on the intestinal wound healing response. In this study, we investigated the role of μ-opioid receptor (MOR) signaling on the unfolded protein response (UPR) using a novel zebrafish model of NSAID-induced intestinal injury. The NSAID glafenine was administered to zebrafish larvae at 5 days post-fertilization (dpf) for up to 24 hours in the presence or absence of the MOR-specific agonist DALDA. By analysis with histology, transmission electron microscopy and vital dye staining, glafenine-treated zebrafish showed evidence of endoplasmic reticulum and mitochondrial stress, with disrupted intestinal architecture and halted cell stress responses, alongside accumulation of apoptotic intestinal epithelial cells in the lumen. Although the early UPR marker BiP was induced with glafenine-induced injury, downstream atf6 and s-xbp1 expression were paradoxically not increased, explaining the halted cell stress responses. The μ-opioid agonist DALDA protected against glafenine-induced injury through induction of atf6-dependent UPR. Our findings show that DALDA prevents glafenine-induced epithelial damage through induction of effective UPR.

Decreased leukocyte recruitment by inorganic nitrate and nitrite in microvascular inflammation and NSAID-induced intestinal injury

Nitric oxide (NO) generated by vascular NO synthases can exert anti-inflammatory effects, partly through its ability to decrease leukocyte recruitment. Inorganic nitrate and nitrite, from endogenous or dietary sources, have emerged as alternative substrates for NO formation in mammals. Bioactivation of nitrate is believed to require initial reduction to nitrite by oral commensal bacteria. Here we investigated the effects of inorganic nitrate and nitrite on leukocyte recruitment in microvascular inflammation and in NSAID-induced small-intestinal injury. We show that leukocyte emigration in response to the proinflammatory chemokine MIP-2 is reduced by 70% after 7days of dietary nitrate supplementation as well as by acute intravenous nitrite administration. Nitrite also reduced leukocyte adhesion to a similar extent and this effect was inhibited by the soluble guanylyl cyclase inhibitor ODQ, whereas the effect on emigrated leukocytes was not altered by this treatment. Further studies in TNF-α-stimulated endothelial cells revealed that nitrite dose-dependently reduced the expression of ICAM-1. In rats and mice subjected to a challenge with diclofenac, dietary nitrate prevented the increase in myeloperoxidase and P-selectin levels in small-intestinal tissue. Antiseptic mouthwash, which eliminates oral nitrate reduction, markedly blunted the protective effect of dietary nitrate on P-selectin levels. Despite attenuation of the acute immune response, the overall ability to clear an infection with Staphylococcus aureus was not suppressed by dietary nitrate as revealed by noninvasive IVIS imaging. We conclude that dietary nitrate markedly reduces leukocyte recruitment to inflammation in a process involving attenuation of P-selectin and ICAM-1 upregulation. Bioactivation of dietary nitrate requires intermediate formation of nitrite by oral nitrate-reducing bacteria and then probably further reduction to NO and other bioactive nitrogen oxides in the tissues.

Proton Pump Inhibitors Exacerbate NSAID-Induced Small Intestinal Injury by Inducing Dysbiosis

Proton pump inhibitors (PPIs) and nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used classes of drugs, with the former frequently coprescribed to reduce gastroduodenal injury caused by the latter. However, suppression of gastric acid secretion by PPIs is unlikely to provide any protection against the damage caused by NSAIDs in the more distal small intestine. Rats were treated with antisecretory doses of omeprazole or lanzoprazole for 9 days, with concomitant treatment with anti-inflammatory doses of naproxen or celecoxib on the final 4 days. Small intestinal damage was blindly scored, and changes in hematocrit were measured. Changes in small intestinal microflora were evaluated by denaturing gradient gel electrophoresis and reverse-transcription polymerase chain reaction. Both PPIs significantly exacerbated naproxen- and celecoxib-induced intestinal ulceration and bleeding in the rat. Omeprazole treatment did not result in mucosal injury or inflammation; however, there were marked shifts in numbers and types of enteric bacteria, including a significant reduction (∼80%) of jejunal Actinobacteria and Bifidobacteria spp. Restoration of small intestinal Actinobacteria numbers through administration of selected (Bifidobacteria enriched) commensal bacteria during treatment with omeprazole and naproxen prevented intestinal ulceration/bleeding. Colonization of germ-free mice with jejunal bacteria from PPI-treated rats increased the severity of NSAID-induced intestinal injury, as compared with mice colonized with bacteria from vehicle-treated rats. PPIs exacerbate NSAID-induced intestinal damage at least in part because of significant shifts in enteric microbial populations. Prevention or reversal of this dysbiosis may be a viable option for reducing the incidence and severity of NSAID enteropathy.

The Neuropeptide DALDA Protects Against NSAID-Induced Acute Intestinal Injury in Zebrafish Larvae

The Neuropeptide DALDA Protects Against NSAID-Induced Acute Intestinal Injury in Zebrafish Larvae

Diazoxide attenuates indomethacin-induced small intestinal damage in the rat

ATP-sensitive potassium (K ATP) channel openers have been shown to protect against cellular damage in neurons, cardiac muscle, and kidney and to effectively reduce nonsteroidal anti-inflammatory drug (NSAID)-induced gastric damage in rats. We investigated the effects of K ATP channel opener diazoxide on small intestinal injury induced in rats by indomethacin administration. The effect of glibenclamide, a K ATP channel blocker, was also evaluated. Diazoxide (15, 45 and 135 mg/kg) or glibenclamide (18 mg/kg), were given by oral gavage 1 h before and 6 h after indomethacin treatment (20 mg/kg p.o.). After 24 h, macroscopic and histologic lesions, myeloperoxidase (MPO) activity and lipid peroxidation levels were evaluated. Diazoxide at 15 mg/kg was ineffective, while at doses of 45 mg/kg and 135 mg/kg was able to significantly improve all damage parameters. Glibenclamide administration enhanced intestinal injury. These results show for the first time a beneficial effect of diazoxide in indomethacin-induced enteritis in the rat. Several mechanisms, such as oxidative phosphorylation uncoupling and hypermotility seem particularly important in NSAID-induced intestinal injury. Such events lead to increased mucosal permeability and to penetration of noxious lumen components, which ignite the inflammatory response. Since K ATP channel openers were shown to protect against mitochondrial damage, to reduce intercellular permeability and to relax smooth muscle, we suggest that diazoxide could exert its beneficial effects by one or more of these actions.