Aspirin induces gastric epithelial barrier dysfunction by activating p38 MAPK via claudin-7

Induction of mitochondrial toxicity by non-steroidal anti-inflammatory drugs (NSAIDs): The ultimate trade-off governing the therapeutic merits and demerits of these wonder drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are most extensively used over-the-counter FDA-approved analgesic medicines for treating inflammation, musculoskeletal pain, arthritis, pyrexia and menstrual cramps. Moreover, aspirin is widely used against cardiovascular complications. Owing to their non-addictive nature, NSAIDs are also commissioned as safer opioid-sparing alternatives in acute trauma and post-surgical treatments. In fact, therapeutic spectrum of NSAIDs is expanding. These "wonder-drugs" are now repurposed against lung diseases, diabetes, neurodegenerative disorders, fungal infections and most notably cancer, due to their efficacy against chemoresistance, radio-resistance and cancer stem cells. However, prolonged NSAID treatment accompany several adverse effects. Mechanistically, apart from cyclooxygenase inhibition, NSAIDs directly target mitochondria to induce cell death. Interestingly, there are also incidences of dose-dependent effects where NSAIDs are found to improve mitochondrial health thereby suggesting plausible mitohormesis. While mitochondria-targeted effects of NSAIDs are discretely studied, a comprehensive account emphasizing the multiple dimensions in which NSAIDs affect mitochondrial structure-function integrity, leading to cell death, is lacking. This review discusses the current understanding of NSAID-mitochondria interactions in the pathophysiological background. This is essential for assessing the risk-benefit trade-offs of NSAIDs for judiciously strategizing NSAID-based approaches to manage pain and inflammation as well as formulating effective anti-cancer strategies. We also discuss recent developments constituting selective mitochondria-targeted NSAIDs including theranostics, mitocans, chimeric small molecules, prodrugs and nanomedicines that rationally optimize safer application of NSAIDs. Thus, we present a comprehensive understanding of therapeutic merits and demerits of NSAIDs with mitochondria at its cross roads. This would help in NSAID-based disease management research and drug development.

The effect of an acute aspirin challenge on intestinal permeability in healthy adults with and without prophylactic probiotic consumption: a double-blind, placebo-controlled, randomized trial

BACKGROUND

Healthy individuals may experience increases in intestinal permeability after chronic or acute use of non-steroidal anti-inflammatory drugs, which may be attenuated by probiotics. This study investigates the effects of an acute aspirin challenge on gastroduodenal barrier function with or without prophylactic probiotic consumption.

METHODS

Twenty-nine generally healthy participants (26 ± 6 years) completed a 14-week randomized, double-blind, crossover trial. A probiotic containing 2 Lactobacilli strains or placebo was administered for 3 weeks, with a 4-week washout period between crossover phases. Daily and weekly questionnaires assessing gastrointestinal function were completed for 2 weeks before until 2 weeks after each intervention to assess gastrointestinal function. Gastroduodenal permeability was assessed by urinary excretion of orally administered sucrose after 1, 2, and 3 weeks of each intervention with a 1950 mg-aspirin challenge after 2 weeks of supplementation. Stool samples were collected weekly during supplementation for detection of species of interest.

RESULTS

Gastroduodenal permeability increased with aspirin challenge (Week 1: 3.4 ± 0.6 μmol vs Week 2: 9.9 ± 1.0 μmol urinary sucrose; p < 0.05). There were no differences in the change in permeability after the aspirin challenge or gastrointestinal function between interventions.

CONCLUSION

The acute aspirin challenge significantly increased intestinal permeability similarly in both groups, and prophylactic probiotic consumption was unable to prevent the loss in this particular model.

Fenpropathrin increases gliquidone absorption via causing damage to the integrity of intestinal barrier

Fenpropathrin is a commonly used pesticide, which was ingested by humans through diet and water. Gliquidone is a common hypoglycemic drug that diabetic patients need for long-term use. This study aimed to investigate the effects of long-term exposure to fenpropathrin on the intestinal barrier and intestinal absorption of the model drug gliquidone. The Ussing Chamber study had shown that fenpropathrin can increase the transport of gliquidone in an isolated intestinal model. In addition, the intestinal absorption of fluorescein was significantly increased in fenpropathrin-exposed rats administered by gavage. Further research suggested that fenpropathrin exposure caused a series of pathological effects: the structure of the intestine was damaged, the expression of tight junction proteins in the intestinal tissue was decreased, the intestinal MDA was increased, the SOD was decreased, and the expression of inflammatory factors was increased. In the Caco-2 cell model, it was found that fenpropathrin can increase the transport of gliquidone in the Caco-2 cell monolayer, reduce the expression of tight junction proteins and increase reactive oxygen species in Caco-2 cells. Fenpropathrin exposure also resulted in decreasing expression of PPAR-γ and UCP-2 in intestinal tissue and Caco-2 cell model, while causing increased expression of p-P38. The above results indicated that fenpropathrin exposure could induce oxidative stress and destroy the intestinal barrier by affecting the expression of p-P38/P38/PPAR-γ/UCP-2 protein, thereby increasing the intestinal absorption of gliquidone. This study provides new insights into the hazards of fenpropathrin residues in the environment.

Accumulation of Deleterious Effects in Gastric Epithelial Cells and Vascular Endothelial Cells In Vitro in the Milieu of Helicobacter pylori Components, 7-Ketocholesterol and Acetylsalicylic Acid

The Gastric pathogen Helicobacter pylori (HP) may influence the development of coronary heart disease (CHD). H. pylori induce reactive oxygen species (ROS), which transform cholesterol to 7-ketocholesterol (7-kCh), a CHD risk factor. Acetylsalicylic acid (ASA)—an Anti-aggregation drug used in CHD patients—may increase gastric bleeding and inflammation. We examined whether H. pylori driven ROS effects in the cell cultures of gastric epithelial cells (AGS) and vascular endothelial cells (HUVEC) progress in the milieu of 7-kCh and ASA. Cell cultures, exposed to 7-kCh or ASA alone or pulsed with the H. pylori antigenic complex—Glycine acid extract (GE), urease (UreA), cytotoxin associated gene A (CagA) protein or lipopolysaccharide (LPS), alone or with 7-kCh and ASA—were examined for ROS, apoptosis, cell integrity, interleukin (IL)-8, the activation of signal transducer, the activator of transcription 3 (STAT3), and wound healing. ASA and 7-kCh alone, and particularly in conjunction with H. pylori components, increased the ROS level and the rate of apoptosis, which was followed by cell disintegration, the activation of STAT3, and IL-8 elevation. AGS cells were unable to undergo wound healing. The cell ROS response to H. pylori components may be elevated by 7-kCh and ASA.

Lactobacillus plantarum MA2 Ameliorates Methionine and Choline-Deficient Diet Induced Non-Alcoholic Fatty Liver Disease in Rats by Improving the Intestinal Microecology and Mucosal Barrier

Non-alcoholic fatty liver disease (NAFLD) has become a highly concerned health issue in modern society. Due to the attentions of probiotics in the prevention of NAFLD, it is necessary to further clarify their roles. In this study, the methionine and choline-deficient (MCD) diet induced NAFLD rats model were constructed and treated with strain L. plantarum MA2 by intragastric administration once a day at a dose of 1 × 10⁸ cfu/g.bw. After 56 days of the therapeutic intervention, the lipid metabolism and the liver pathological damage of the NAFLD rats were significantly improved. The content of total cholesterol (TC) and total triglyceride (TG) in serum were significantly lower than that in the NAFLD group (p < 0.05). Meanwhile, the intestinal mucosal barrier and the structure of intestinal microbiota were also improved. The villi length and the expression of claudin-1 was significantly higher than that in the NAFLD group (p < 0.05). Then, by detecting the content of LPS in the serum and the LPS-TLR4 pathway in the liver, we can conclude that Lactobacillus plantarum MA2 could reduce the LPS by regulating the gut microecology, thereby inhibit the activation of LPS-TLR4 and it downstream inflammatory signaling pathways. Therefore, our studies on rats showed that L. plantarum MA2 has the potential application in the alleviation of NAFLD. Moreover, based on the application of the strain in food industry, this study is of great significance to the development of new therapeutic strategy for NAFLD.

Dehydroevodiamine ameliorates indomethacin-induced gastric injury via inhibition of ERK and p38 signaling pathway

BACKGROUND

Dehydroevodiamine (DHE), a pivotal quinazoline alkaloid isolated from Fructus Evodiae (Tetradium ruticarpum (A. Juss.) Hartley), has various pharmacological effects. However, the effect of DHE on gastric injury is still uncharted.

PURPOSE

To clarify the pharmacological effect and mechanism of DHE on gastric injury (GI) induced by indomethacin (IDO).

STUDY DESIGN

The gastric injury was induced in rat by oral administration of 5 mg/kg IDO for 7 days. Then the rats were treated with DHE (10, 20, 40 mg/kg, ig) for 7 days.

METHODS

The changes of food intake, body weight, gastric pH and general state observation were determined. And HE staining and AB-PAS staining was analyzed. Then, the inflammatory infiltration of gastric tissue was observed through MPO immunohistochemical approach, and the expression of TNF-α, IL-6 and IL-10 were measured. Furthermore, the levels of proteins ERK, p-ERK, P38, p-P38, JNK and p-JNK were determined to elucidate the molecular mechanism of DHE.

RESULTS

DHE alleviated food intake reduction, weight loss and gastric injury induced by IDO and made gastric pH and mucosal thickness return to normal. In addition, DHE could down regulate the expression of MPO, TNF-α and IL-6 and up regulate the expression of IL-10 to reduce the damage induced by inflammatory, and create a healing environment. Furthermore, DHE could significantly inhibit the phosphorylation of ERK and p38 not JNK.

CONCLUSION

DHE ameliorated dyspepsia, inflammatory infiltration and tissue damage induced by IDO through ERK and p38 signaling pathways rather than JNK pathway.

An Observational Study to Evaluate the Association between Intestinal Permeability, Leaky Gut Related Markers, and Metabolic Health in Healthy Adults

We explored whether metabolic health is linked to intestinal permeability, using a multi-sugar (MS) permeability test, and whether intestinal permeability is correlated with the leaky gut-related markers (LGM) zonulin, LBP, and sCD14. Metabolically healthy (n = 15) and unhealthy subjects (n = 15) were recruited based on waist circumference, fasting glucose, and high-density lipoprotein cholesterol levels. Participants underwent an MS permeability test that assessed site-specific permeabilities of the gastroduodenum and small and large intestines. The test was performed with/without an acetylsalicylic acid challenge to measure and correlate the gut permeability, LGM, and metabolic health. At baseline, metabolic health showed no correlation with gut permeability. Significant correlations were found between the metabolic health parameters and LGM. In the acetylsalicylic acid challenged MS permeability test, low-density lipoprotein cholesterol was correlated with the sucralose/erythritol ratio, reflecting the whole intestinal permeability. Correlations between most metabolic health parameters and LGM during the acetylsalicylic acid challenge were less pronounced than at baseline. In both MS permeability tests, no significant correlations were found between LGM (plasma and serum) and gut permeability. Thus, correlations between LGM and metabolic health might not be linked with paracellular gut permeability. Transcellular translocation and/or lipoprotein-related transportation is a more likely mechanism underlying the association between LGM and metabolic health.

Effect of aspirin to intentionally induce leaky gut on performance, inflammation, and carcass characteristics of feedlot cattle

The negative impacts of stress on gastrointestinal tract (GIT) barrier function can result in compromised animal growth and health. Aspirin is known to cause mucosal injury leading to increased gut permeability and tight junction damage and can be used as a model to study leaky gut in cattle. The objective of this study was to determine the long-term impact of aspirin-induced chronic leaky gut on cattle growth and carcass attributes. Two treatments were evaluated in two studies: control (no aspirin) or 0.25% of the diet dry matter (DM) aspirin fed daily. Diets consisted of 50% corn, 24% dried distillers grains, 20% corn silage, and 6% supplement on a DM basis. In experiment 1, sixteen Angus × Simmental heifers, allotted by body weight (BW) and breed composition, were fed diets for 154 d. On day 155, heifers were dosed with 1 liter of a 180-mM Cr-ethylenediaminetetraacetic acid solution using an esophageal tube and had urine collected every 1.5 to 3 h for 48 h for analysis of Cr as a measure of gut leakiness. In experiment 2, ninety-six Simmental × Angus steers (355.0 ± 14.8 kg) were allotted by BW and breed composition and fed treatment diets for 159 d. Weight was recorded monthly and serum was collected on day 159 and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6 (IL-6), serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase (AST). Data were analyzed using the MIXED procedure of SAS. Heifers fed 0.25% aspirin in experiment 1 excreted more Cr into urine compared with heifers not fed aspirin (overall treatment effect, P = 0.01). In experiment 2, aspirin tended to increase serum LBP (P = 0.06) but had no effect on concentrations of IL-6, haptoglobin, SAA, or AST (P ≥ 0.25). Aspirin tended to decrease average daily gain (P = 0.10), decreased hot carcass weight and rib-eye area (P ≤ 0.05), and increased fat thickness, marbling score, and yield grade (P ≤ 0.02). Aspirin tended to increase kidney, pelvic, and heart fat percentage (P = 0.10) and had no effect on liver abscesses (P ≥ 0.80). This study indicates that leaky gut induced by long-term administration of aspirin has negative impacts on feedlot performance and carcass composition. The negative impact of aspirin-induced leaky gut on animal performance suggests that chronic leaky gut caused by other factors (subacute acidosis, stress) may be a significant problem for the feedlot industry.

Loxoprofen enhances intestinal barrier function via generation of its active metabolite by carbonyl reductase 1 in differentiated Caco-2 cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used worldwide as antipyretic analgesics and agents for rheumatoid arthritis and osteoarthritis, but known to cause damage to the gastrointestinal mucosae as their serious adverse effects. Few studies showed the impairment of intestinal epithelial barrier function (EBF) by high concentrations (0.5-1 mM) of NSAIDs, but the underlying mechanism is not fully understood. This study is aimed at clarifying effects at a low concentration (50 μM) of three NSAIDs, loxoprofen (Lox), ibuprofen and indomethacin, on intestinal EBF using human intestinal epithelial-like Caco-2 cells. Among those NSAIDs, Lox increased the transepithelial electric resistance (TER) value, decreased the paracellular Lucifer yellow CH (LYCH) permeability, and upregulated claudin (CLDN)-1, -3 and -5, indicating that low doses of Lox enhanced EBF through increasing expression of CLDNs. Lox is known to be metabolized to a pharmacologically active metabolite, (2S,1'R,2'S)-loxoprofen alcohol (Lox-RS), by carbonyl reductase 1 (CBR1), which is highly expressed in human intestine. CBR1 was expressed in the Caco-2 cells, and the pretreatment with a CBR1 inhibitor suppressed both the Lox-evoked CLDN upregulation and EBF enhancement. In addition, the treatment of the cells with Lox-RS resulted in higher TER value and lower LYCH permeability than those with Lox. Thus, Lox-RS synthesized by CBR1 may greatly contribute to the improving efficacy of Lox on the barrier function. Since EBF is decreased in inflammatory bowel disease, we finally examined the effect of Lox on EBF using the Caco-2/THP-1 co-culture system, which is used as an in vitro inflammatory bowel disease model. Lox significantly recovered EBF which was impaired by inflammatory cytokines secreted from THP-1 macrophages. These in vitro observations suggest that Lox enhances intestinal EBF, for which the metabolism of Lox to Lox-RS by CBR1 has an important role.

The Epithelial Cell Leak Pathway

The epithelial cell tight junction structure is the site of the transepithelial movement of solutes and water between epithelial cells (paracellular permeability). Paracellular permeability can be divided into two distinct pathways, the Pore Pathway mediating the movement of small ions and solutes and the Leak Pathway mediating the movement of large solutes. Claudin proteins form the basic paracellular permeability barrier and mediate the movement of small ions and solutes via the Pore Pathway. The Leak Pathway remains less understood. Several proteins have been implicated in mediating the Leak Pathway, including occludin, ZO proteins, tricellulin, and actin filaments, but the proteins comprising the Leak Pathway remain unresolved. Many aspects of the Leak Pathway, such as its molecular mechanism, its properties, and its regulation, remain controversial. In this review, we provide a historical background to the evolution of the Leak Pathway concept from the initial examinations of paracellular permeability. We then discuss current information about the properties of the Leak Pathway and present current theories for the Leak Pathway. Finally, we discuss some recent research suggesting a possible molecular basis for the Leak Pathway.

Ethanol-induced lymphatic endothelial cell permeability via MAP-kinase regulation

Chronic alcohol alters the immune system enhancing the susceptibility to inflammation, bacterial, and viral infections in alcohol users. We have shown that alcohol causes increased permeability of mesenteric lymphatic vessels in alcohol-fed rats. The mechanisms of alcohol-induced lymphatic leakage are unknown. Endothelial cell monolayer permeability is controlled by junctional proteins complexes called tight junctions (TJ) and adherens junctions (AJ), and each can be regulated by MAPK activation. We hypothesize that ethanol induces lymphatic endothelial cell (LEC) permeability via disruption of LEC TJ through MAPK activation. An in vitro model of rat LECs was used. Ethanol-supplemented medium was added at concentrations of 0, 25, and 50 mM to confluent cells. Resistance-based barrier function, transwell permeability, cell viability, TJ, AJ, and MAPK protein activity, TJ and AJ gene expressions, and the role of p38 MAPK in barrier function regulation were measured. Ethanol increased the permeability of LECs compared to controls that was not associated with decreased cell viability. LECs treated with 50 mM ethanol showed an increase in phosphorylated levels of p38. No significant changes in TJ and AJ gene or protein expressions were observed after ethanol treatment. p38 inhibition prevented ethanol-induced increases in permeability. These findings suggest that p38 may play a role in the regulation of ethanol-induced LEC permeability, but altered permeability may not be associated with decreased TJ or AJ protein expression. Further investigation into junctional protein localization is needed to better understand the effects of ethanol on lymphatic endothelial cell-to-cell contacts and hyperpermeability.

The ameliorative effect of Lactobacillus plantarum Y44 oral administration on inflammation and lipid metabolism in obese mice fed with a high fat diet

In our previous studies, Lactobacillus plantarum Y44 showed antioxidant activity and favorable gastric and intestinal transit tolerance. The purpose of this study is to determine whether L. plantarum Y44 could ameliorate intestinal inflammation and lipid metabolism disorder in obese mice fed with a high-fat diet. L. plantarum Y44 was administered by gavage to the mice fed with a high-fat diet for 12 weeks. The mice fed with a high fat diet only showed sustainably elevated body weight, liver lipid metabolism disorder, intestinal inflammation and a lower short chain fatty acid content in feces. Oral administration of L. plantarum Y44 regulated lipid metabolism disorder by inhibiting the expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) in the liver of obese mice, reducing the contents of total cholesterol (TC), triacylglycerols (TG), low density lipoprotein cholesterol (LDL-c), alanine aminotransferase (ALT), and aspartate transaminase (AST) and increasing the content of high-density lipoprotein cholesterol (HDL-c) in the serum of obese mice. Oral administration of L. plantarum Y44 up-regulated the expression of colon tight junction protein such as claudin-1 and occludin, down-regulated p38 and phospho-p38 levels and reduced serum interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α). Oral administration of L. plantarum Y44 increased Muribaculaceae, Rikenellaceae, and Lactobacillaceae levels, reduced the Firmicutes/Bacteroidetes ratio, and Desulfovibrionaceae and Proteobacteria levels in obese mice. Oral administration of L. plantarum Y44 also enhanced the contents of propionic acid, butyric acid, butanoicacid-3-methyl, pentanoic acid and acetic acid in the feces of the obese mice. Correlation analysis of Spearman revealed a significant correlation between changes in intestinal microflora and obesity-related symptoms. L. plantarum Y44 ameliorated intestinal inflammation and lipid metabolism disorders by modulating gut microbiota.

Integrating Network Pharmacology and Experimental Validation to Decipher the Mechanism of Action of Huanglian Jiedu Decoction in Treating Atherosclerosis

Background

This study used network pharmacology, molecular docking and experimental validation to assess the effects of Huanglian Jiedu Decoction (HLJDD) on atherosclerosis (AS).

Methods

The components and targets of HLJDD were analyzed using the Traditional Chinese Medicine Systems Pharmacology database, and information on the genes associated with AS was retrieved from the GeneCards and OMIM platforms. Protein–protein interactions were analyzed using the STRING platform. A component–target–disease network was constructed using Cytoscape. GO and KEGG analyses were performed to identify molecular biological processes and signaling pathways, and the predictions were verified experimentally. Molecular docking was conducted with ChemOffice software, PyMOL software and Vina to verify the correlation of targets and compounds.

Results

HLJDD contained 31 active compounds, with quercetin, kaempferol, moupinamide and 5-hydroxy-7-methoxy-2-(3,4,5-trimethoxyphenyl)chromone as the core compounds. The most important biotargets of HLJDD in AS were ICAM-1, CD31 and RAM-11. The molecular docking results showed that the molecular docking interaction energy between the 3 key targets and the 4 high-degree components were much less than −5 kJ∙mol⁻¹. The experimental validation results showed that HLJDD might treat AS mainly by reducing TC, TG and LDL-C and increasing HDL-C, upregulating CD31 expression, reducing ICAM-1 and RAM-11 expression, and downregulating inflammatory factors, including CRP, IL-6 and TNF-α. These results support the network pharmacology data and demonstrate that HLJDD affects the expression of core genes and alters the leukocyte transendothelial migration signaling pathway.

Conclusion

Based on network pharmacology and experimental validation, our study indicated that HLJDD exerted anti-AS effect through upregulating CD31 expression and reducing the expression of ICAM-1 and RAM-11. HLJDD may be a potential therapeutic drug to the prevention of AS.

Mechanisms of deoxynivalenol-induced endocytosis and degradation of tight junction proteins in jejunal IPEC-J2 cells involve selective activation of the MAPK pathways

Mycotoxin contamination in foods is a major risk factor for human and animal health due to its prevalence in cereals and their by-products. Deoxynivalenol (DON), mainly produced by Fusarium genera, is the most common mycotoxin detected in cereal products. Deoxynivalenol disrupts intestinal barrier function and decreases protein levels of tight junction proteins (TJP). However, the overall mechanism by which DON regulates specific TJP turnover and epithelial cell integrity remains unclear. Herein, we show that DON (2 μM) decreases the protein stability and accelerates the degradation of TJP in the lysosome. Interestingly, pretreatment of cells with dynasore (a dynamin-dependent endocytosis inhibitor) protected against DON-induced degradation of claudin-3 and 4. Immunofluorescence analysis also shows that the decreased membrane presence of claudin-4 and ZO-1 induced by DON is reversible with dynamin inhibition, whereas the pretreatment with cytochalasin D (an actin-dependent endocytosis inhibitor) reverses the degradation of claudin-1 and 4 induced by DON. We also show that the endocytosis and degradation of claudin-1 is regulated by p38 mitogen-activated protein kinase (MAPK), whereas the endocytosis of claudin-4 and ZO-1 is mediated by c-Jun-N-terminal kinase (JNK). Resveratrol, with JNK inhibitory activity, also prevents the endocytosis and degradation of claudin-4 and ZO-1 and protects against DON-induced decrease in transepithelial electrical resistance (TEER) and increase in FITC-dextran permeability. Collectively, this study, for the first time, shows that DON accelerates the endocytosis and degradation of TJP and this is regulated by the activation of p38 MAPK and JNK signaling pathways. Therefore, natural bioactive compounds with p38 MAPK and JNK inhibitory activities may be effective in preventing the DON-induced TJP disruption and preserve gut barrier function in vivo.

NMR-Guided Repositioning of Non-Steroidal Anti-Inflammatory Drugs into Tight Junction Modulators

Bioavailability is a major bottleneck in the clinical application of medium molecular weight therapeutics, including protein and peptide drugs. Paracellular transport of these molecules is hampered by intercellular tight junction (TJ) complexes. Therefore, safe chemical regulators for TJ loosening are desired. Here, we showed a potential application of select non-steroidal anti-inflammatory drugs (NSAIDs) as TJ modulators. Based on our previous observation that diclofenac and flufenamic acid directly bound various PDZ domains with a broad specificity, we applied solution nuclear magnetic resonance techniques to examine the interaction of other NSAIDs and the first PDZ domain (PDZ1) of zonula occludens (ZO)-1, ZO-1(PDZ1). Inhibition of ZO-1(PDZ1) is expected to provide loosening of the epithelial barrier function because the domain plays a crucial role in maintaining TJ integrity. Accordingly, diclofenac and indomethacin were found to decrease the subcellular localization of claudin (CLD)-2 but not occludin and ZO-1 at the apicolateral intercellular compartment of Madin–Darby canine kidney (MDCK) II cells. These NSAIDs exhibited 125–155% improved paracellular efflux of fluorescein isothiocyanate insulin for the Caco-2 cell monolayer. We propose that these NSAIDs can be repurposed as drug absorption enhancers for peptide drugs.

Panax Notoginseng Saponin Attenuates Gastric Mucosal Epithelial Cell Injury Induced by Dual Antiplatelet Drugs through COX and PI3K/Akt/ VEGF-GSK-3β-RhoA Network Pathway

OBJECTIVE

To elucidate the underlying mechanism of Panax notoginseng saponin (PNS) on gastric epithelial cell injury and barrier dysfunction induced by dual antiplatelet (DA).

METHODS

Human gastric mucosal epithelial cell (GES-1) was cultured and divided into 4 groups: a control, a DA, a PNS+DA and a LY294002+PNS+DA group. GES-1 apoptosis was detected by flow cytometry, cell permeability were detected using Transwell, level of prostaglandins E2 (PGE2), 6-keto-prostaglandin F1α (6-keto-PGF1α) and vascular endothelial growth factor (VEGF) in supernatant were measured by enzyme linked immunosorbent assay (ELISA), expression of phosphatidylinositide 3-kinase (PI3K), phosphorylated-PI3K (p-PI3K), Akt, phosphorylated-Akt (p-Akt), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), glycogen synthase kinase-3β (GSK-3β) and Ras homolog gene family member A (RhoA) were measured by Western-blot.

RESULTS

DA induced apoptosis and hyper-permeability in GES-1, reduced supernatant level of PGE2, 6-keto-PGF1α and VEGF (P<0.05). Addition of PNS reduced the apoptosis of GES-1 caused by DA, restored the concentration of PGE2, 6-keto-PGF1α and VEGF (P<0.05). In addition, PNS attenuated the alteration of COX-1 and COX-2 expression induced by DA, up-regulated p-PI3K/p-Akt, down-regulated RhoA and GSK-3β. LY294002 mitigated the effects of PNS on cell apoptosis, cell permeability, VEGF concentration, and expression of RhoA and GSK-3β significantly.

CONCLUSIONS

PNS attenuates the suppression on COX/PG pathway from DA, alleviates DA-induced GES-1 apoptosis and barrier dysfunction through PI3K/Akt/VEGF-GSK-3β-RhoA network pathway.

BPC 157 Rescued NSAID-cytotoxicity Via Stabilizing Intestinal Permeability and Enhancing Cytoprotection

The stable gastric pentadecapeptide BPC 157 protects stomach cells, maintains gastric integrity against various noxious agents such as alcohol, nonsteroidal anti-inflammatory drugs (NSAIDs), and exerts cytoprotection/ adaptive cytoprotection/organoprotection in other epithelia, that is, skin, liver, pancreas, heart, and brain. Especially BPC 157 counteracts gastric endothelial injury that precedes and induces damage to the gastric epithelium and generalizes "gastric endothelial protection" to protection of the endothelium of other vessels including thrombosis, prolonged bleeding, and thrombocytopenia. In this background, we put the importance of BPC 157 as a possible way of securing GI safety against NSAIDs-induced gastroenteropathy since still unmet medical needs to mitigate NSAIDs-induced cytotoxicity are urgent. Furthermore, gastrointestinal irritants such as physical or mental stress, NSAIDs administration, surfactants destroyer such as bile acids, alcohol can lead to leaky gut syndrome through increasing epithelial permeability. In this review article, we described the potential rescuing actions of BPC 157 against leaky gut syndrome after NSAIDs administration for the first time.

Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle

Stress negatively affects the gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. A deeper understanding of how diet and stress impacts the GIT barrier function in feedlot cattle is needed. Aspirin decreases mucus production and mucosal repair in the GIT and could be used as a model for GIT barrier dysfunction research. The objective of this study was to evaluate the effectiveness of aspirin to induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425.0 ± 8.6 kg) were allotted to 0, 50, 100, or 200 mg/kg body weight (BW) aspirin doses based on BW. Experiment 1 consisted of two periods separated by 4 wk where four heifers per treatment received the same aspirin dose during each period. Heifers were fed a 49.4% corn silage and 50.6% concentrate diet. The 200 mg/kg BW aspirin treatment was dosed as a 100 mg/kg BW aspirin oral bolus 36 and 24 h prior to Cr-ethylenediaminetetraacetic acid (EDTA) dosing (1 liter; 180 mM). The 50 and 100 mg/kg BW aspirin treatments were dosed as an oral bolus 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr. Serum was collected at 0 and 48 h and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6, serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase. In experiment 2, sixteen crossbred steers (576.0 ± 14.2 kg) fed a similar diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (eight steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected, and claudin (CLDN) 1, 2, and 3, occludin, and zonula occludens tight junction messenger ribonucleic acid (mRNA) expression was determined. Data were analyzed using the MIXED procedure of SAS. Urinary Cr excretion increased linearly at hours 3, 6, 9, and 12 (P ≤ 0.04) as aspirin dose increased from 0 to 200 mg/kg. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rates and linearly decreased mean retention time of Cr (P = 0.02). Aspirin increased SAA (P = 0.04) and tended to increase LBP (P = 0.09) in serum but did not affect any other serum inflammatory marker (P ≥ 0.19). Aspirin tended to increase jejunal CLDN-1 mRNA expression (P = 0.10) but did not affect the mRNA expression of other genes regulating tight junction function (P ≥ 0.20). Results from this study indicate that aspirin disrupts the GIT barrier function in beef cattle and has a potential as a model in GIT permeability research.

Zika virus dysregulates human Sertoli cell proteins involved in spermatogenesis with little effect on tight junctions

Zika virus (ZIKV), a neglected tropical disease until its re-emergence in 2007, causes microcephaly in infants and Guillain-Barré syndrome in adults. Its re-emergence and spread to more than 80 countries led the World Health Organization in 2016 to declare a Public Health Emergency. ZIKV is mainly transmitted by mosquitos, but can persist in infected human male semen for prolonged periods and may be sexually transmitted. Testicular Sertoli cells support ZIKV replication and may be a reservoir for persistent ZIKV infection. Electrical impedance analyses indicated ZIKV infection rapidly disrupted Vero cell monolayers but had little effect upon human Sertoli cells (HSerC). We determined ZIKV-induced proteomic changes in HSerC using an aptamer-based multiplexed technique (SOMAscan) targeting >1300 human proteins. ZIKV infection caused differential expression of 299 proteins during three different time points, including 5 days after infection. Dysregulated proteins are involved in different bio-functions, including cell death and survival, cell cycle, maintenance of cellular function, cell signaling, cellular assembly, morphology, movement, molecular transport, and immune response. Many signaling pathways important for maintenance of HSerC function and spermatogenesis were highly dysregulated. These included IL-6, IGF1, EGF, NF-κB, PPAR, ERK/MAPK, and growth hormone signaling. Down-regulation of the PPAR signaling pathway might impact cellular energy supplies. Upstream molecule analysis also indicated microRNAs involved in germ cell development were downregulated by infection. Overall, this study leads to a better understanding of Sertoli cellular mechanisms used by ZIKV during persistent infection and possible ZIKV impacts on spermatogenesis.

Impaired gastric mucosal integrity identified by confocal endomicroscopy in Helicobacter pylori-negative functional dyspepsia

BACKGROUND

Low-grade inflammation may be involved in the pathogenesis of functional dyspepsia (FD). We hypothesis that altered gastric permeability is involved in the onset and persistence of this disorder. Therefore, our aim was to evaluate gastric mucosal integrity and mast cell numbers in patients with FD.

METHODS

We enrolled 58 patients with FD fulfilling the Rome III criteria (H Pylori negative), 20 inflammatory control subjects (H Pylori positive), and 20 healthy controls (H Pylori negative). Probe-based confocal endomicroscopy was performed using intravenous fluorescein to assess the paracellular fluorescein leakage and cell shedding. Mast cells were identified with quantitative immunohistochemistry on mucosal biopsies.

KEY RESULTS

Endomicroscopic score of paracellular permeability was significantly higher in H pylori-negative FD patients compared with healthy controls (1.45 ± 1.27 vs 3.69 ± 3.18, P = .006). However, FD patients and healthy controls did not show differences in cell shedding score (0.75 ± 0.79 vs 1.29 ± 1.14, P = .069). Mast cell numbers were significantly increased compared with healthy control samples (18.91 ± 5.47 vs 14.1 ± 3.88, P < .001). The magnitude of increase in permeability was positively correlated with mast cell numbers of FD patients (rs = .6588, P < .0001), but not dyspepsia symptom scores.

CONCLUSION AND INFERENCES

Impaired gastric barrier function is present in FD patients. This might provide a new pathophysiological mechanism and therapeutical target in FD.

Aspirin enhances sensitization to the egg-white allergen ovalbumin in rats

Enhancement of oral absorption of food allergens by non-steroidal anti-inflammatory drugs (NSAIDs), especially aspirin, is considered an exacerbating factor in the development of food allergies. In this study, we examined the effect of aspirin on oral sensitization to and absorption of the egg-white allergen ovalbumin (OVA) in rats. The absorption of OVA was evaluated by measuring the plasma concentration of OVA after oral administration by gavage. To evaluate oral sensitization to OVA, plasma levels of immunoglobulin (Ig) E and IgG₁ antibodies (Abs) specific to OVA were determined by enzyme-linked immunosorbent assay after initiation of sensitization. High-dose aspirin (30 mg/kg) increased oral OVA absorption and plasma levels of OVA-specific IgE and IgG₁ Abs compared with those observed in vehicle-treated rats. In contrast, low-dose aspirin (3 mg/kg) exerted no changes in either absorption or sensitization. Spermine, an absorption enhancer, increased the oral absorption of OVA to nearly the same extent as high-dose aspirin, whereas the plasma levels of OVA-specific IgE and IgG₁ Abs exhibited no significant differences between spermine- and vehicle-treated rats. Among the NSAIDs, diclofenac and indomethacin increased sensitization to OVA, similar to high-dose aspirin, but meloxicam exerted no effects on Ab levels. In conclusion, we showed that high-dose aspirin enhanced oral sensitization to OVA. Our study suggests that enhanced oral sensitization to OVA cannot be ascribed to increased absorption of OVA from the intestinal tract. Although the mechanisms underlying this enhancement of sensitization are still controversial, our study suggests that modification of cytokine production due to impairment of the intestinal barrier function and inhibition of cyclooxygenase-1 activity by aspirin may be involved.

Identifying and managing patients at risk of severe allergic reactions to food: Report from two iFAAM workshops

Food allergy affects a small but important number of children and adults. Much of the morbidity associated with food allergy is driven by the fear of a severe reaction and fatalities continue to occur. Foods are the commonest cause of anaphylaxis. One of the aims of the European Union-funded Integrated Approaches to Food Allergen and Allergy Risk Management (iFAAM) project was to improve the identification and management of children and adults at risk of experiencing a severe reaction. A number of interconnected studies within the project have focused on quantifying the severity of allergic reactions; the impact of food matrix, immunological factors on severity of reactions; the impact of co-factors such as medications on the severity of reactions; utilizing single-dose challenges to understand threshold and severity of reactions; and community studies to understand the experience of patients suffering real-life allergic reactions to food. Associated studies have examined population thresholds and co-factors such as exercise and stress. This paper summarizes two workshops focused on the severity of allergic reactions to food. It outlines the related studies being undertaken in the project indicating how they are likely to impact on our ability to identify individuals at risk of severe reactions and improve their management.

Effect of Lactobacillus paracasei N1115 and fructooligosaccharides in nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a growing health concern worldwide. Administration of probiotics and prebiotics has been proposed as a convenient and effective treatment. Our study aims to evaluate the therapeutic benefits of Lactobacillus paracasei N1115 (N1115) and fructooligosaccharides (FOS) by examining the histopathogenesis and underlying molecular events of NAFLD.

MATERIAL AND METHODS

An NAFLD mouse model was established by feeding C57BL/6 mice with a high-fat diet (HFD). N1115, FOS and synbiotics were administered for 16 weeks.

RESULTS

N1115, FOS and synbiotics alleviated HFD-induced hepatic steato-sis and release of tumor necrosis factor-α, and slowed the progression of cirrhosis. Compared to the HFD group, these dietary supplements reduced serum total triglyceride and cholesterol, and appeared to decrease the fasting blood glucose and insulin. Intraperitoneal glucose tolerance tests, homeostatic model assessment of insulin resistance and real-time PCR showed that the regimens could overcome insulin resistance. These findings were associated with the transcriptional repression of inflammatory factors such as lipopolysaccharides, Toll-like receptor 4 and nuclear factor-κB. Lastly, N1115, FOS, and synbiotics improved the intestinal barrier functions and histologic integrity. This was accompanied by the restoration of the p38 MAPK pathway and in-creased expression of the tight junction components occludin-1 and claudin-1.

CONCLUSIONS

N1115, FOS and synbiotics are effective in the prevention and treatment of NAFLD. Our data support the translation of these agents into clinical evaluation in human subjects with NAFLD and/or associated risk factors.

Intestinal absorption of the wheat allergen gliadin in rats

BACKGROUND

Aspirin enhances food allergy symptoms by increasing absorption of ingested allergens. The objective of this study is to elucidate the role of aspirin in facilitating intestinal absorption of the wheat allergen, gliadin, in rats.

METHODS

Plasma concentrations of gliadin were determined after oral administration by gavage or administration into a closed intestinal loop in rats. We used an in situ intestinal re-circulating perfusion experiment to examine the effect of pepsin on aspirin-facilitated gliadin absorption. Fluorescein isothiocyanate (FITC)-labeled dextran-40 (FD-40) was used as a marker of non-specific absorption. The molecular size of gliadin and its allergenicity in plasma were examined using immunoblot analysis and intradermal reaction tests with Evans blue dye (EBD) extravasation, respectively.

RESULTS

Aspirin increased plasma concentrations of gliadin after oral administration but had no effect in the closed intestinal loop study. An in situ intestinal re-circulating perfusion study showed that FITC-labeled gliadin was absorbed similarly to FD-40. Aspirin increased absorption of both intact and pepsin-digested gliadin, with a more significant effect on absorption of pepsin-treated gliadin. Immunoblotting showed that most gliadin was absorbed in intact form. When the gliadin fraction was extracted from rat plasma after gavage and injected intradermally into gliadin-sensitized rats, EBD extravasation was observed at injection sites in a gliadin dose-dependent manner.

CONCLUSIONS

Aspirin increased the absorption of intact and pepsin-digested gliadin via the paracellular pathway, maintaining their allergenicity. Moreover, the effect of aspirin on gliadin absorption was enhanced by modification and digestion of gliadin in the stomach.

Transport of Flavanolic Monomers and Procyanidin Dimer A2 across Human Adenocarcinoma Stomach Cells (MKN-28)

It has been proven that A-type procyanidins, containing an additional ether bond, compared to B-type procyanidins are also bioavailable in vitro and in vivo. However, their bioavailability and absorption in the gastrointestinal tract remain uncertain. In this study, a model of the human adenocarcinoma stomach cell line (MKN-28) was established to explore the cellular transport of flavanolic monomers and procyanidin dimer A2, which were isolated from the litchi pericarp extract. After the integrity and permeability of the cell monolayer were ensured by measurement of the transepithelial electrical resistance and the apparent permeability coefficient for Lucifer yellow, the transportation of procyanidins A2 and B2, (-)-epicatechin (EC), and (+)-catechin (CC) was studied at pH 3.0, 5.0, or 7.0 in the apical side, with compound concentrations of 0.05 and 0.1 mg/mL based on the cytotoxicity test. High-performance liquid chromatography and liquid chromatography-mass spectrometry analyses indicated that EC, CC, and A2 were transported in the MKN-28 cell line from 30 to 180 min, while B2 showed no transport. The maximal transport efficiencies of EC, CC, and A2 were 23 ± 0.81, 13.16 ± 1.53, and 16.41 ± 1.36%, respectively, existing at 120, 180, and 120 min of transportation. Laser scanning confocal microscopy analysis presented the dynamic transmission of EC, in accordance with the result of concentration determination, suggesting that the A-type procyanidins are possibly absorbed through the stomach barrier, which is pH- and time-dependent.

Modulation of Intestinal Epithelial Permeability by Plasma from Patients with Crohn's Disease in a Three-dimensional Cell Culture Model

Intestinal epithelial barrier is affected by multiple factors, such as tumour necrosis factor-α (TNF-α). Plasma concentration of TNF-α is higher in patients with Crohn’s disease (CD) than healthy controls (HC) and correlates positively with disease activity. This study aimed to determine the effect of plasma from active, inactive CD patients on intestinal barrier function and to investigate the underlying mechanism. Plasma samples were collected from CD patients and HC. 3D Caco-2 cysts were treated with plasma or TNF-α, with or without pre-incubation of adalimumab (a monoclonal antibody that antagonizes TNF-α) or JNK inhibitor SP600125. The results demonstrated that exposure of the cysts to plasma from CD patients resulted in enhanced paracellular permeability in a disease activity-dependent manner. Compared to HC, active CD plasma decreased ZO-1 and OCCLUDIN expression on mRNA and protein levels, and led to an increased JNK phosphorylation. Pre-incubation with adalimumab or SP600125 ameliorated TJ disruption and barrier dysfunction induced by plasma from CD patients. These results indicate that plasma from CD patients is able to induce epithelial barrier disruption, in part through TNF-α induced TJs modulation. The data also demonstrate an involvement of MAPK pathway, in particular the JNK isoform, in CD patient plasma-induced barrier dysfunction.

Sex-associated preventive effects of low-dose aspirin on obesity and non-alcoholic fatty liver disease in mouse offspring with over-nutrition in utero

Aspirin has been found to diminish hypertriglyceridemia and hyperglycemia in both obese rodents and patients with type 2 diabetes mellitus. We aimed to test whether low-dose aspirin can prevent obesity and the progression of non-alcoholic fatty liver disease (NAFLD) in high-risk subjects. We used offspring mice with maternal over-nutrition as a high-risk model of obesity and NAFLD. The offspring were given postnatal HF-diet and diethylnitrosamine (DEN) to induce obesity and NAFLD, and were treated with or without a low dose of aspirin for 12 weeks (ASP or CTL groups). Aspirin treatment reduced body weight gain, reversed glucose intolerance, and depressed hepatic lipid accumulation in female, but not in male mice. Female mice displayed re-sensitized insulin/Akt signaling and overactivated AMPK signaling, with enhanced level of hepatic PPAR-γ, Glut4, and Glut2, while male mice only enhanced hepatic PPAR-α and PPAR-γ levels. The female ASP mice had inhibited p44/42 MAPK activity and enhanced Pten expression, while male displayed activated p38 MAPK signaling. Furthermore, the female but not the male ASP mice reduced Wnt-signaling activity via both the epigenetic regulation of Apc expression and the post-transcriptional regulation of β-catenin degradation. In summary, our study demonstrates a sex-associated effect of low-dose aspirin on obesity and NAFLD prevention in female but not in male mice.

Bioengineering a novel 3D in vitro model of gastric mucosa for stomach permeability studies

The field of stomach-directed therapeutics and diagnosis is still hampered by the lack of reliable in vitro models that closely mimic the gastric mucosa where gastric cancer cells are generally confined. Here we propose a rapid, complex, and innovative 3D in vitro model of the gastric mucosa, by extending a conventional gastric monolayer model to an inner stratum of the mucosa - the lamina propria. The developed model comprises normal stomach fibroblasts embedded in a 3D RGD-modified alginate hydrogel prepared on the basolateral side of a Transwell® insert, mimicking the extracellular matrix and cellular component of the lamina propria, onto which a moderately differentiated adenocarcinoma stomach cell line (MKN74) was seeded, reproducing the physiological conditions of the gastric barrier. The integrity and functionality of the in vitro model was evaluated through permeability studies of FITC-dextran and 200 nm fluorescent polystyrene nanoparticles at gastric conditions. Nanoparticle transport was pH-dependent and strongly impacted by the biomimetic lamina propria, highlighting that a gastric extracellular matrix (ECM)-like microenvironment should be integrated in an in vitro permeability model to be adopted as a reliable evaluation tool of innovative therapeutics and diagnosis of gastric diseases. STATEMENT OF SIGNIFICANCE: Current in vitro models of the gastric mucosa are limited to simplistic 2D cell culture systems, which ignore the dimensionality of the stomach wall and make it difficult to reliably test new therapeutic approaches to gastric pathologies. By combining stomach fibroblasts embedded within a 3D RGD-modified alginate hydrogel and epithelial gastric cancer cells in a Transwell® system, we established a new biomimetic model of the stomach mucosa. Epithelial cells recreate the gastric epithelium, while the cell-laden 3D hydrogel recapitulates both the cellular composition and dimensionality of the extracellular matrix of gastric lamina propria. This cellularized 3D model stands as a promising evaluation platform to assist the development of new strategies for the treatment and diagnosis of gastric diseases.

Anisomycin, a JNK and p38 activator, suppresses cell-cell junction formation in 2D cultures of K38 mouse keratinocyte cells and reduces claudin-7 expression, with an increase of paracellular permeability in 3D cultures

Keratinocytes in the oral mucosal epithelium, which is a non-keratinized stratified epithelium, are exposed to various stimuli from the oral cavity. JNK and p38 are stress-activated mitogen-activated protein kinases (MAPKs) that are phosphorylated by various stimuli and are involved in the assembly and disassembly of tight junctions (TJs) in keratinocytes. Therefore, we investigated the effects of stress-activated MAPKs on TJs in a mouse keratinocyte cell line during cell-cell junction formation in two-dimensional (2D) cultures or stratification to form non-keratinized epithelium in 3D cultures. In 2D cultures, calcium induced zipper-like staining for ZO-1 at 2 h and string-like staining for ZO-1 at 12 h, which indicated immature and mature cell-cell junctions, respectively. Anisomycin (AM), a JNK and p38 activator, inhibited formation of string-like staining for ZO-1, whereas inhibition of JNK, but not p38, after AM treatment restored string-like staining for ZO-1, although claudins (CLDNs) 4, 6, and 7 did not completely colocalize to ZO-1-positive sites. In 3D cultures, AM treatment for 2 weeks activated only p38, suppressed flattening of the superficial cells, removed CLDN7 from ZO-1-positive spots on the surface of 3D cultures, which represent TJs, and decreased transepithelial electrical resistance. Thus, short-term AM treatment inhibited maturation of cell-cell junctions by JNK, but not p38, activation. p38 activation by long-term AM treatment affected morphology of stratified structures and paracellular permeability, which was increased by CLDN7 removal from TJs. Various chronic stimuli that activate stress-activated MAPKs may weaken the keratinocyte barrier and be involved in TJ-related diseases.

Network pharmacology-based identification of protective mechanism of Panax Notoginseng Saponins on aspirin induced gastrointestinal injury

BACKGROUND & AIMS

Aspirin is the first line therapy for cardiovascular and cerebrovascular diseases and is widely used. However aspirin-induced gastrointestinal injury is one of its most common side effect which limits long-term use. Panax Notoginseng Saponins(PNS) which is also used to prevent thrombus may alleviate this side effect according to previous clinical evidences. Owing to the complexity of drug combination, the protective mechanism of PNS on aspirin-induced gastrointestinal injury remains unclear. Therefore, a network pharmacology-based strategy was proposed in this study to address this problem.

METHODS

A network pharmacology approach comprising multiple components, candidate targets of each component, known therapeutic targets, network analysis has been used in this study. Also, we establish aspirin-induced gastrointestinal injury model by the oral administration of aspirin (0.5 g/kg body weight) to verify the predicted targets from network pharmacology. All rats was randomly allocated to control groups (n = 6),aspirin groups (n = 6)and aspirin + PNS groups (n = 6) and conducted H&E staining and ELISA for VEGFA.

RESULTS

The comprehensive systematic approach was successfully to identify 5 compounds and 154 candidate targets in PNS and 479 candidate targets in aspirin. After network establishment and analysis, 27 potential targets hit by PNS, aspirin and 6 kind of gastrointestinal diseases were found. The experiments results indicated that aspirin group has visible inflammation and lesions while aspirin + PNS group have not. The higher expression of VEGFA in aspirin + PNS group verified the predicted potential protective targets of PNS.

CONCLUSIONS

PNS may have protective function for aspirin-induced gastrointestinal injury through increasing VEGFA expression. Network pharmacology strategy may provide a forceful tool for exploring the mechanism of herb medicine and discovering novel bioactive ingredients.

Helicobacter pylori infection impairs gastric epithelial barrier function via microRNA‑100‑mediated mTOR signaling inhibition

Helicobacter pylori (H. pylori) infection has an important effect on human health as it is an established cause of gastric carcinoma. microRNAs (miRNAs/miRs) are a family of small RNAs with various functions in the control of cellular profiles. However, the effect of miR‑100 in H. pylori infection remains unknown. Healthy volunteers (n=100) and patients with H. pylori infection (n=98) were included in the present study. H. pylori infection was confirmed by urea breath tests. The levels of miR‑100 in gastroscopic biopsy samples and cultured GES‑1 cells were measured by reverse transcription‑quantitative polymerase chain reaction. Furthermore, miR‑100 was overexpressed or inhibited in GES‑1 cells by an miR‑100 mimic or inhibitor, respectively. The expression of cell‑junction proteins and members of the mechanistic target of rapamycin kinase (mTOR) signaling pathway was investigated by western blotting. The results demonstrated that miR‑100 levels were upregulated in infected patients and cultured gastric epithelial cells, compared with the respective controls. Additionally, the expression of epithelial (E)‑cadherin and zona occludens‑1 in the gastric mucosa of infected patients and GES‑1 cells was downregulated. Furthermore, infected gastric epithelial cells exhibited impaired barrier functions, as measured by resistance and permeability tests. Overexpression of miR‑100 inhibited junction protein expression, as well as the activation of the mTOR signaling pathway, while suppression of miR‑100 restored E‑cadherin expression and mTOR signaling. The results of the present study indicate that H. pylori infection may cause dysfunction of the gastric epithelial barrier by increasing miR‑100 levels, which subsequently inhibit mTOR signaling. These results may have potential applications affecting miR‑100 in H. pylori‑related diseases.

Apple Polyphenol Suppresses Indomethacin-Induced Gastric Damage in Experimental Animals by Lowering Oxidative Stress Status and Modulating the MAPK Signaling Pathway

Indomethacin is a nonsteroid anti-inflammatory drug (NSAID) that is used to alleviate pain and inflammation in clinical medicine. Previous studies indicated that NSAIDs can cause gastrointestinal mucosal complications, and it is associated with mucosal lipid peroxidation and oxidative damage. Based on the evidences, decreasing oxidative stress may be an ideal therapeutic strategy for preventing gastrointestinal ulcer. Apple (Rosaceae Malus sp.) is one of the most commonly consumed fruits worldwide. The abundant polyphenolic constituents have received increasing attention for decades. In both in vivo and in vitro studies, the reports showed that apple polyphenol (AP) seems to provide an indirect antioxidant protection by activating cellular antioxidant enzymes to defend against oxidative stress. To address this issue and develop AP into a healthy improvement supplement, we studied the effect and potential mechanisms of AP in indomethacin-treated animal. The results showed AP can decelerate the gastric lesion, significantly suppress lipid peroxidation, increase the level of glutathione and the activity of catalase, and regulate the MAPK signaling proteins. These findings imply that AP protects the gastric mucosa from indomethacin-caused lesions and the protection is at least partially attributable to its antioxidative properties. This alternative medical function of AP may be a safe and effective intervention for preventing indomethacin-induced gastric complications.

Aspirin and non-steroidal anti-inflammatory drugs use reduce gastric cancer risk: A dose-response meta-analysis

Background

The association between non-steroidal anti-inflammatory drugs (NSAIDs) and gastric cancer (GC) risk is controversial. The aim of this study is to evaluate the chemopreventive effect of NSAIDs for GC.

Methods

A literature search was performed for relevant studies using the PubMed and Embase database (up to March 2016). Risk ratios (RRs) and 95% confidence intervals (CIs) were used as the effect measures. The dose–response analysis and subgroup analysis were also performed.

Results

Twenty-four studies were included. Our results indicated that NSAIDs could reduce GC risk (any NSAIDs: RR=0.78, 96%CI=0.72-0.85; aspirin: RR=0.70, 95%CI=0.62-0.80; non-aspirin NSAIDs: RR=0.86, 95%CI=0.80-0.94), especially for non-cardia GC risk. Moreover, the dose-response analysis indicated the risk of GC decreased by 11% and 5% for 2 years increment of any NSAIDs and aspirin use, respectively. There were nonlinear relationships between the frequency of any NSAIDs use and aspirin use and GC risk (P for non-linearity<0.01), with a threshold effect of 5 times/week. A monotonically decreasing trend was observed only for the frequency of less than 5 times/week.

Conclusions

Our results indicate that NSAIDs is inversely associated with GC risk, especially for non-cardia GC risk. NSAIDs use may become a feasible approach to prevent GC.

The role of mucus in cell-based models used to screen mucosal drug delivery

The increasing interest in developing tools to predict drug absorption through mucosal surfaces is fostering the establishment of epithelial cell-based models. Cell-based in vitro techniques for drug permeability assessment are less laborious, cheaper and address the concerns of using laboratory animals. Simultaneously, in vitro barrier models that thoroughly simulate human epithelia or mucosae may provide useful data to speed up the entrance of new drugs and new drug products into the clinics. Nevertheless, standard cell-based in vitro models that intend to reproduce epithelial surfaces often discard the role of mucus in influencing drug permeation/absorption. Biomimetic models of mucosae in which mucus production has been considered may not be able to fully reproduce the amount and architecture of mucus, resulting in biased characterization of permeability/absorption. In these cases, artificial mucus may be used to supplement cell-based models but still proper identification and quantification are required. In this review, considerations regarding the relevance of mucus in the development of cell-based epithelial and mucosal models mimicking the gastro-intestinal tract, the cervico-vaginal tract and the respiratory tract, and the impact of mucus on the permeability mechanisms are addressed. From simple epithelial monolayers to more complex 3D structures, the impact of the presence of mucus for the extrapolation to the in vivo scenario is critically analyzed. Finally, an overview is provided on several techniques and methods to characterize the mucus layer over cell-based barriers, in order to intimately reproduce human mucosal layer and thereby, improve in vitro/in vivo correlation.

Increased expression of tight junction protein occludin is associated with the protective effect of mosapride against aspirin-induced gastric injury

Mosapride is known to affect gastric motility, however whether mosapride has anti-ulcergenic effects in gastric mucosal injury is unclear. The aim of the present study was to investigate the effects of mosapride on aspirin-induced gastric injuries. GES-1 cells were cultured and divided into 5 groups: Control group, aspirin injury group (treated with 18.2 mmol/l aspirin) and mosapride pretreatment groups (treated with 0.4, 0.5, or 0.6 µmol/l mosapride). Cell proliferation was evaluated via MTT assay and cell apoptosis was investigated via flow cytometry. The expression of occludin was determined by western blot analysis. A total of 40 male Sprague-Dawley rats were randomized into five groups: Control group, aspirin injury group (150 mg/kg) and mosapride pretreatment groups (0.25, 0.50 or 0.75 mg/kg). Gastric mucosal lesions were induced by administering 200 mg/kg aspirin daily for 4 days. Rats in the mosapride groups were pretreated with mosapride 1 h prior to aspirin administration. Histological changes were evaluated under a light microscope and gastric epithelial TJs were observed via transmission electron microscopy. The results revealed that cell apoptosis was significantly increased in the aspirin injury group compared with the control (P<0.05), whereas apoptosis was significantly decreased in the mosapride pretreatment groups compared with the aspirin group (P<0.05). Cell viability was significantly increased in the mosapride pretreatment groups compared with the aspirin injury group (P<0.05), and that of the aspirin injury group was significantly decreased compared with the control group (P<0.05). Compared with the aspirin injury group, occludin expression was significantly increased in the three mosapride pre-treatment groups (all P<0.05). It was also demonstrated that gastric damage was significantly attenuated in the mosapride pretreatment groups compared with the aspirin injury group (P<0.05). Impaired TJ integrity was observed in aspirin injury group, whereas TJs in the mosapride groups were almost intact. In conclusion, the results of the present study suggest that mosapride exerts a gastroprotective action on aspirin-induced gastric mucosal injury at least in part via attenuating cell apoptosis and increasing occludin expression.

Food-Dependent, Exercise-Induced Anaphylaxis: Diagnosis and Management in the Outpatient Setting

Food-dependent, exercise-induced anaphylaxis is a disorder in which anaphylaxis develops most predictably during exercise, when exercise takes place within a few hours of ingesting a specific food. IgE to that food should be demonstrable. It is the combination of the food and exercise that precipitates attacks, whereas the food and exercise are each tolerated independently. Recently, it was demonstrated that exercise is not essential for the development of symptoms, and that if enough of the culprit food is ingested, often with additional augmentation factors, such as alcohol or acetylsalicylic acid, symptoms can be induced at rest in the challenge setting. Thus, food-dependent, exercise-induced anaphylaxis appears to be more correctly characterized as a food allergy syndrome in which symptoms develop only in the presence of various augmentation factors, with exercise being the primary one. However, additional factors are not usually present when the patient exercises normally, so ongoing investigation is needed into the physiologic and cellular changes that occur during exercise to facilitate food-induced anaphylaxis.

Membrane-free culture and real-time barrier integrity assessment of perfused intestinal epithelium tubes

In vitro models that better reflect in vivo epithelial barrier (patho-)physiology are urgently required to predict adverse drug effects. Here we introduce extracellular matrix-supported intestinal tubules in perfused microfluidic devices, exhibiting tissue polarization and transporter expression. Forty leak-tight tubules are cultured in parallel on a single plate and their response to pharmacological stimuli is recorded over 125 h using automated imaging techniques. A study comprising 357 gut tubes is performed, of which 93% are leak tight before exposure. EC₅₀-time curves could be extracted that provide insight into both concentration and exposure time response. Full compatibility with standard equipment and user-friendly operation make this Organ-on-a-Chip platform readily applicable in routine laboratories.

Efforts to determine the effects of drugs on epithelial barriers could benefit from better in vitro models. Here the authors develop a microfluidic device supporting the growth and function of extracellular matrix-supported intestinal tubules, and evaluate the effect of staurosporine and acetylsalicylic acid on barrier integrity.

Biological properties of citral and its potential protective effects against cytotoxicity caused by aspirin in the IEC-6 cells

Citral, 3,7-dimethyl-2,6-octadienal, is a key component of several essential oils extracted from lemon-scented herbal plants. The present study was designed to investigate the antioxidant activities of citral and assess its possible protective effects against aspirin-induced toxicity in vitro. We used IEC-6 cells (rat small intestine epithelial cells). The antioxidant activities were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), β-carotene/linoleic acid and Ferric reducing antioxidant power (FRAP). Cytotoxicity was evaluated by cell viability, anti-oxidant enzyme activities, malondialdehyde (MDA) production and by the expression of MAPKs (Mitogen-Activated Protein Kinases) pathways. According to results, citral showed an important antioxidant activity. It inhibited the oxidation of linoleic acid, a moderate DPPH was found and it showed a Ferric reducing antioxidant potential with an EC₅₀ value of 125±28.86μg/mL. Then, the co-treatment of aspirin with citral significantly decreased the aspirin-induced cell death, and the MDA level. It modulated the superoxide dismutase (SOD) and glutathione (GSH) activities. Also, the activation of MAPKs was attenuated by citral. These findings suggest that citral can protect IEC-6 cells against aspirin-induced oxidative stress that may help to discover new chemicals out of natural antioxidant substances.

Runner's diarrhea: what is it, what causes it, and how can it be prevented?

PURPOSE OF REVIEW

Runner's diarrhea is an acute exercise-induced diarrhea. Usually, this is not a pathological situation but it can affect performance. This review focuses on the discussion of the main causes of runner's diarrhea and nutritional recommendations to prevent it.

RECENT FINDINGS

Although based on limited data, multiple transportable carbohydrate intake during exercise instead of glucose alone can be recommended for preventing the urge to defecate and (possibly) diarrhea. Additionally, avoiding ingestion of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) is related to a lower incidence of reported gastrointestinal problems. There is, however, still no study that associates FODMAPs and runner's diarrhea. Gluten-free diets seem to have no impact on exercise-induced intestinal damage and there is no evidence to recommend this diet for the prevention of diarrhea in nonceliac athletes.

SUMMARY

The main causes of diarrhea in runners are ischemic, mechanical, and nutritional factors. For the prevention of diarrhea, it has been recommended that dehydration and the ingestion of fiber, fat, protein, high concentrated carbohydrate beverages, FODMAPs, caffeine, bicarbonate, and nonsteroidal anti-inflammatory drugs be avoided. However, the causes of diarrhea and nutritional strategies to prevent it are based on limited research and more studies are definitely needed.

A Quinacrine Analogue Selective Against Gastric Cancer Cells: Insight from Biochemical and Biophysical Studies

One of the earliest synthetic antimalarial drugs, quinacrine, was recently reported as interesting for the treatment of acute myeloid leukemia. Inspired by this and similar findings, we evaluated a set of quinacrine analogues against gastric (MKN-28), colon (Caco-2), and breast (MFC-7) cancer cell lines and one normal human fibroblast cell line (HFF-1). All the compounds, previously developed by us as dual-stage antimalarial leads, displayed antiproliferative activity, and one of the set stood out as selective toward the gastric cancer cell line, MKN-28. Interestingly, this compound was transported across an in vitro MKN-28 model cell line in low amounts, and approximately 80 % was trapped inside those cells. Nuclear targeting of the same compound and its interactions with calf thymus DNA were assessed through combined fluorescence microscopy, spectroscopy, and calorimetry studies, which provided evidence for the compound's ability to reach the nucleus and to interact with DNA.

Claudins in cancer: bench to bedside

The claudin family, in mammals, encoded by at least 27 members of a single ancestral gene, CLDN, is the main constituent as integral membrane proteins of tight junctions. It has been shown that the expression levels of claudins are often decreased or that their expressions are absent in human neoplasias. These findings are consistent with the well-accepted concept that carcinogenesis is accompanied by the disruption or loss of functional tight junctions. In contrast, accumulating data have showed elevated or aberrant expression of claudins in various cancers, indicating specific roles of claudins in tumorigenesis. Importantly, dysregulated claudins play an oncogenic role or conversely have a tumor-suppressive effect depending on target tissues or cell types, and thus, they contribute to tumor development and progression. Although tight junctions are intercellular structures in epithelial cells, specific roles of claudins in cancer are supported by the evidence that TJs are not simple static constituents for establishing cell adhesion structures but are also cell signaling components that have functions in receiving environmental cues and transmitting signals inside cells. Since the expression profile of claudins is associated with patients' outcome and prognosis in several cancer types, an understanding of the expression pattern and subcellular localization of claudins in various pathologies will lead to the establishment of claudins as useful biomarkers for the detection and diagnosis of cancers.

Early Activation of MAPK p44/42 Is Partially Involved in DON-Induced Disruption of the Intestinal Barrier Function and Tight Junction Network

Deoxynivalenol (DON), produced by the plant pathogens Fusarium graminearum and Fusarium culmorum, is one of the most common mycotoxins, contaminating cereal and cereal-derived products. Although worldwide contamination of food and feed poses health threats to humans and animals, pigs are particularly susceptible to this mycotoxin. DON derivatives, such as deepoxy-deoxynivalenol (DOM-1), are produced by bacterial transformation of certain intestinal bacteria, which are naturally occurring or applied as feed additives. Intestinal epithelial cells are the initial barrier against these food- and feed-borne toxins. The present study confirms DON-induced activation of MAPK p44/42 and inhibition of p44/42 by MAPK-inhibitor U0126 monoethanolate. Influence of DON and DOM-1 on transepithelial electrical resistance (TEER), viability and expression of seven tight junction proteins (TJ), as well as the potential of U0126 to counteract DON-induced effects, was assessed. While DOM-1 showed no effect, DON significantly reduced TEER of differentiated IPEC-J2 and decreased expression of claudin-1 and -3, while leaving claudin-4; ZO-1, -2, and -3 and occludin unaffected. Inhibition of p44/42 counteracted DON-induced TEER decrease and restored claudin-3, but not claudin-1 expression. Therefore, effects of DON on TEER and claudin-3 are at least partially p44/42 mediated, while effects on viability and claudin-1 are likely mediated via alternative pathways.

Connexin43 hemichannels contributes to the disassembly of cell junctions through modulation of intracellular oxidative status

Connexin (Cx) hemichannels regulate many cellular processes with little information available regarding their mechanisms. Given that many pathological factors that activate hemichannels also disrupts the integrity of cellular junctions, we speculated a potential participation of hemichannels in the regulation of cell junctions. Here we tested this hypothesis. Exposure of renal tubular epithelial cells to Ca²⁺-free medium led to disassembly of tight and adherens junctions, as indicated by the reduced level of ZO-1 and cadherin, disorganization of F-actin, and severe drop in transepithelial electric resistance. These changes were preceded by an activation of Cx43 hemichannels, as revealed by extracellular efflux of ATP and intracellular influx of Lucifer Yellow. Inhibition of hemichannels with chemical inhibitors or Cx43 siRNA greatly attenuated the disassembly of cell junctions. Further analysis using fetal fibroblasts derived from Cx43 wide-type (Cx43^+/+), heterozygous (Cx43^+/-) and knockout (Cx43^-/-) littermates showed that Cx43-positive cells (Cx43^+/+) exhibited more dramatic changes in cell shape, F-actin, and cadherin in response to Ca²⁺ depletion, as compared to Cx43-null cells (Cx43^-/-). Consistently, these cells had higher level of protein carbonyl modification and phosphorylation, and much stronger activation of P38 and JNK. Hemichannel opening led to extracellular loss of the major antioxidant glutathione (GSH). Supplement of cells with exogenous GSH or inhibition of oxidative sensitive kinases largely prevented the above-mentioned changes. Taken together, our study indicates that Cx43 hemichannels promote the disassembly of cell junctions through regulation of intracellular oxidative status.

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The mechanisms about the coordinated regulation of cell junctions are obscure.

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Ca²⁺ depletion activates hemichannels and disrupts cell junctions.

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Hemichannel opening exaggerates oxidative stress via efflux of GSH.

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Blocking hemichannels attenuates oxidative stress and cell junction disassembly.

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Hemichannels regulate cell junctions via modulation of intracellular redox status.

Role of regenerating gene I in claudin expression and barrier function in the small intestine

We have recently shown that loss of the regenerating gene (Reg) I causes susceptibility to nonsteroidal anti-inflammatory drug-induced gastrointestinal damage. However, the mechanism by which Reg I plays a protective role against this pathophysiological condition is unclear. Here, we investigated whether Reg I plays roles in the induction of tight junction proteins and mucosal barrier function in the small intestine. The small-intestinal permeability was evaluated in Reg I-deficient mice by FITC-dextran and transepithelial electrical resistance (TEER) assay. The effect of REG Iα on TEER, claudins expression, and intracellular signaling was examined using Caco2 cells in vitro. Small-intestinal expression of claudins 3 and 4 was investigated in Reg I-deficient mice in vivo. REG I deficiency significantly decreased the expression of claudin 3 in the small-intestinal epithelium. When mice were treated with indomethacin, the serum level of FITC-dextran in Reg I knockout mice was significantly higher than that in wild-type (WT) mice. The level of small-intestinal TEER was significantly decreased in Reg I knockout mice compared with WT mice under normal condition. REG Iα stimulation significantly enhanced the level of TEER in Caco2 cells. Treatment with REG Iα enhanced the expression of claudins 3 and 4 and promoted Sp1, Akt, and ERK phosphorylation in Caco2 cells, whereas these effects were attenuated by treatment with anti-REG Iα antibody. Reg I may play a role in the maintenance of mucosal barrier function by inducing tight junction proteins such as claudins 3 and 4.

Indomethacin induces increase in gastric epithelial tight junction permeability via redistribution of occludin and activation of p38 MAPK in MKN-28 Cells

Tight Junctions (TJ) create a paracellular barrier that is compromised when nonsteriodal anti-inflammatory drugs (NSAIDs) injure the gastric epithelium, leading to increased permeability. However, the mechanism of NSAID-induced gastric injury is unclear. Here, we examined the effect of indomethacin on barrier function and TJ in gastric MKN-28 cells. In concentration response studies, 500 µm indomethacin induced a significant decrease in transepithelial resistance (TER; 380 vs. 220 Ω·cm(2) for control and indomethacin-treated cells respectively, p < 0.05), and increased dextran permeability by 0.2 vs 1.2 g/l (p < 0.05). These changes in barrier function were completely ameliorated by the p38 MAPK inhibitor (SB-203580) but not by JNK inhibitor (SP-600125) or MEK/ERK inhibitor (PD-98059). SiRNA knock down of p38 MAPK prevented the loss of barrier function caused by indomethacin in MKN-28 cells. Western analyses of TJ proteins revealed that expression of occludin was reduced by indomethacin, whereas there was no change in other TJ proteins. The loss of occludin expression induced by indomethacin was prevented by inhibition of p38 MAPK but not JNK or ERK and also by siRNA of p38 MAPK. Immunofluorescence revealed disruption of occludin localization at the site of the tight junction in indomethacin-treated cells, and this was attenuated by inhibition of p38 MAPK. NSAID injury to murine gastric mucosa on Ussing chambers revealed that indomethacin caused a significant drop in TER and increased paracellular permeability. Pretreatment with the p38 MAPK inhibitor significantly attenuated the disruption of barrier function, but JNK and MEK/ERK inhibition had no effect. Western blot analysis on gastric mucosa reveled loss of TJ protein occludin by indomethacin, which was prevented by inhibition of p38 MAPK. This data suggests that indomethacin compromises the gastric epithelial barrier via p38 MAPK inducing occludin alterations in the TJs.

Inhibition of p38 MAPK activation attenuates esophageal mucosal damage in a chronic model of reflux esophagitis

BACKGROUND

Reflux esophagitis (RE) is one of the common gastrointestinal diseases that are increasingly recognized as a significant health problem. This study was designed to investigate the role of p38 mitogen-activated protein kinase (MAPK) in experimental chronic RE model of rats.

METHODS

Chronic acid RE rats were induced by fundus ligation and partial obstruction of the pylorus and treated with SB203580 (a p38 MAPK inhibitor, i.p., 1 mg/kg/day) for 14 days.

KEY RESULTS

Immunohistochemical staining and Western blotting results revealed the activation of p38 MAPK signaling in the esophagus mucosa 14 days post injury. Through gross and histological assessment, we found that inhibition of p38 MAPK activation by SB203580 attenuated esophageal mucosal damage in RE rats. Inhibition of p38 MAPK activation in RE rats attenuated esophageal barrier dysfunction, through enhancing the expression of tight junction proteins and reducing the expression of matrix matalloproteinases-3 and -9. Inhibition of p38 MAPK activation in RE rats reduced CD68-positive cells in esophagus mucosa and mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β in esophagus and protein levels of TNF-α, IL-6, and IL-1β in serum. In addition, we found that inhibition of p38 MAPK activation in RE rats suppressed protein expression of inducible nitric oxide synthase and reduced formation of nitric oxide (NO), 3-nitrotyrosin, and malondialdehyde in esophagus.

CONCLUSIONS & INFERENCES

Inhibition of p38 MAPK activation attenuated esophageal mucosal damage in acid RE rats, possibly by modulating esophageal barrier function and regulating inflammatory cell recruitment, and the subsequent formation of cytokines, NO, and reactive oxygen species.