In oesophageal squamous cells exposed to acidic bile salt medium, omeprazole inhibits IL-8 expression through effects on nuclear factor-?B and activator protein-1.
ABSTRACT: Oesophagitis might result from the effects of chemokines produced by oesophageal cells in response to gastro-oesophageal reflux, and not solely from the direct, caustic effects of refluxed gastric juice. Proton pump inhibitors (PPI) can block chemokine production through mechanisms independent of their antisecretory effects. We studied omeprazole effects on chemokine production by oesophageal epithelial cells exposed to acidic bile salts.Human primary and telomerase-immortalised oesophageal squamous cells were exposed to acidic bile salt medium with or without omeprazole pretreatment. Interleukin (IL)-8 expression was determined by RT-PCR and ELISA. IL-8 promoter activity was measured by luciferase reporter assay. Binding of NF-?B and AP-1 subunits to the IL-8 promoter was assessed by chromatin immunoprecipitation (ChIP) assay. Immune cell migration induced by conditioned medium was determined by a double-chamber migration assay system.Acidic bile salt medium caused oesophageal epithelial cells to express IL-8 mRNA and protein by activating the IL-8 promoter through NF-?B and AP-1 binding. Omeprazole inhibited that acidic bile salt-stimulated IL-8 expression by blocking the nuclear translocation of p65 (an NF-?B subunit), and by blocking the binding of p65, c-jun and c-fos (AP-1 subunits) to the IL-8 promoter. Omeprazole also blocked the ability of conditioned medium from cells exposed to acidic bile salts to induce immune cell migration.In oesophageal squamous epithelial cells, omeprazole inhibits IL-8 expression through effects on NF-?B and AP-1 that are entirely independent of effects on gastric acid secretion. These previously unrecognised PPI effects might contribute to the healing of reflux oesophagitis.
Project description:Eosinophilic oesophagitis (EoE) and gastro-oesophageal reflux disease (GORD) can have similar clinical and histological features. Proton pump inhibitors (PPIs) are used to distinguish the disorders, with the assumption that only GORD can respond to PPIs. Oesophageal expression of eotaxin-3 stimulated by Th2 cytokines might contribute to oesophageal eosinophilia in EoE. Th2 cytokine effects on the oesophagus in GORD are not known. The objective of the authors was to explore the molecular mechanisms of Th2 cytokines on eotaxin-3 expression by oesophageal squamous cells from patients with GORD and EoE, and the effects of omeprazole on that eotaxin-3 expression.Using telomerase-immortalised and primary cultures of oesophageal squamous cells from GORD and EoE patients, the authors measured eotaxin-3 protein secretion stimulated by Th2 cytokines (interleukin (IL)-4 and IL-13). Eotaxin-3 promoter constructs were used to study transcriptional regulation. Cytokine-induced eotaxin-3 mRNA and protein expression were measured in the presence or absence of omeprazole.There were no significant differences between EoE and GORD primary cells in cytokine-stimulated eotaxin-3 protein secretion levels. In EoE and GORD cell lines, IL-4 and IL-13 activated the eotaxin-3 promoter, and significantly increased eotaxin-3 mRNA and protein expression. Omeprazole blocked the cytokine-stimulated increase in eotaxin-3 mRNA and protein expression in EoE and GORD cell lines.Oesophageal squamous cells from GORD and EoE patients express similar levels of eotaxin-3 when stimulated by Th2 cytokines, and omeprazole blocks that eotaxin-3 expression. These findings suggest that PPIs might have eosinophil-reducing effects independent of effects on acid reflux and that response to PPIs might not distinguish EoE from GORD.
Project description:The presence of bile is not an uncommon finding in acidic oesophageal and extra-oesophageal refluxate, possibly affecting the hypopharyngeal mucosa and leading to neoplastic events. We recently demonstrated that acidic bile (pH ? 4.0) can induce NF-?B activation and oncogenic mRNA phenotype in normal hypopharyngeal cells and generate premalignant changes in treated hypopharyngeal mucosa. We hypothesize that curcumin, a dietary inhibitor of NF-?B, may effectively inhibit the acidic bile-induced cancer-related mRNA phenotype, in treated human hypopharyngeal primary cells (HHPC), supporting its potential preventive use in vivo. Luciferase assay, immunofluorescence, Western blot, qPCR and PCR microarray analysis were used to explore the effect of curcumin in HHPC exposed to bile (400 ?mol/L) at acidic and neutral pH. Curcumin successfully inhibited the acidic bile-induced NF-?B signalling pathway (25% of analysed genes), and overexpression of NF-?B transcriptional factors, c-REL, RELA(p65), anti-apoptotic bcl-2, oncogenic TNF-?, EGFR, STAT3, WNT5A, ?Np63 and cancer-related IL-6. Curcumin effectively reduced bile-induced bcl-2 overexpression at both acidic and neutral pH. Our novel findings suggest that, similar to pharmacologic NF-?B inhibitor, BAY 11-7082, curcumin can suppress acidic bile-induced oncogenic mRNA phenotype in hypopharyngeal cells, encouraging its future in vivo pre-clinical and clinical explorations in prevention of bile reflux-related pre-neoplastic events mediated by NF-?B.
Project description:In an earlier study wherein we induced acute reflux by interrupting proton pump inhibitor (PPI) therapy in patients with reflux oesophagitis (RO) healed by PPIs, we refuted the traditional concept that RO develops as an acid burn. The present study explored our alternative hypothesis that RO results from reflux-stimulated production of pro-inflammatory molecules mediated by hypoxia-inducible factors (HIFs).Using oesophageal biopsies taken from patients in our earlier study at baseline and at 1 and 2?weeks off PPIs, we immunostained for HIF-1?, HIF-2? and phospho-p65, and measured pro-inflammatory molecule mRNAs. We exposed human oesophageal squamous cell lines to acidic bile salts, and evaluated effects on HIF activation, p65 function, pro-inflammatory molecule production and immune cell migration.In patient biopsies, increased immunostaining for HIF-2? and phospho-p65, and increased pro-inflammatory molecule mRNA levels were seen when RO redeveloped 1 or 2?weeks after stopping PPIs. In oesophageal cells, exposure to acidic bile salts increased intracellular reactive oxygen species, which decreased prolyl hydroxylase function and stabilised HIF-2?, causing a p65-dependent increase in pro-inflammatory molecules; conditioned media from these cells increased T cell migration rates. HIF-2? inhibition by small hairpin RNA or selective small molecule antagonist blocked the increases in pro-inflammatory molecule expression and T cell migration induced by acidic bile salts.In patients developing RO, increases in oesophageal HIF-2? correlate with increased pro-inflammatory molecule expression. In oesophageal epithelial cells, acidic bile salts stabilise HIF-2?, which mediates expression of pro-inflammatory molecules. HIF-2? appears to have a role in RO pathogenesis.NCT01733810; Results.
Project description:The fundamental mechanisms underlying erosive oesophagitis and subsequent development of Barrett's oesophagus (BO) are poorly understood. Here, we investigated the contribution of specific components of the gastric refluxate on adhesion molecules involved in epithelial barrier maintenance. Cell line models of squamous epithelium (HET-1A) and BO (QH) were used to examine the effects of bile acids on cell adhesion to extracellular matrix proteins (Collagen, laminin, vitronectin, fibronectin) and expression of integrin ligands (?3 , ?4, ?5 , ?6 and ?? ). Experimental findings were validated in human explant oesophageal biopsies, a rat model of gastroesophageal reflux disease (GORD) and in patient tissue microarrays. The bile acid deoxycholic acid (DCA) specifically reduced adhesion of HET-1A cells to vitronectin and reduced cell-surface expression of integrin-?? via effects on endocytic recycling processes. Increased expression of integrin-?v was observed in ulcerated tissue in a rat model of GORD and in oesophagitis and Barrett's intestinal metaplasia patient tissue compared to normal squamous epithelium. Increased expression of integrin-?? was observed in QH BO cells compared to HET-1A cells. QH cells were resistant to DCA-mediated loss of adhesion and reduction in cell-surface expression of integrin-?? . We demonstrated that a specific component of the gastric refluxate, DCA, affects the epithelial barrier through modulation of integrin ?? expression, providing a novel mechanism for bile acid-mediated erosion of oesophageal squamous epithelium and promotion of BO. Strategies aimed at preventing bile acid-mediated erosion should be considered in the clinical management of patients with GORD.
Project description:AIMS: To investigate the efficacy of daily maintenance treatment with omeprazole 10 mg in reducing the relapse rate of healed erosive oesophagitis. METHODS: Three hundred patients with erosive oesophagitis (grade 2 or greater) received omeprazole 20 mg daily for 12 weeks, followed by 40 mg daily for a further 12 weeks if required. After healing, patients were randomised to double blind treatment with omeprazole 10 mg daily or placebo for up to 18 months. On relapse the treatment cycle was repeated. RESULTS: The cumulative healing rate at 12 weeks in the initial healing period was 95%, and 96% and 98% on rehealing courses after relapse in the first and second maintenance periods respectively. After 12 weeks of treatment, 98% of patients were free from heartburn and 97% were free of all reflux related symptoms. Relapse in the subgroup of patients who relapsed in both maintenance periods was infrequent on omeprazole 20 mg daily: only 9% at two years. Gastrin concentrations rose above normal in one third of patients. One patient had linear hyperplasia of endocrine cells and another had micronodular hyperplasia. There were no side effects definitely attributable to omeprazole. CONCLUSION: Maintenance treatment with omeprazole 10 mg daily keeps about 60% of patients with erosive oesophagitis in prolonged remission. Patients relapsing once are likely to do so again; they can subsequently be treated effectively with omeprazole 20 mg daily.
Project description:Bile-containing gastro-duodenal reflux has been clinically considered an independent risk factor in hypopharyngeal carcinogenesis. We recently showed that the chronic effect of acidic bile, at pH 4.0, selectively induces NF-?B activation and accelerates the transcriptional levels of genes, linked to head and neck cancer, in normal hypopharyngeal epithelial cells. Here, we hypothesize that NF-?B inhibition is capable of preventing the acidic bile-induced and cancer-related mRNA phenotype, in treated normal human hypopharyngeal cells. In this setting we used BAY 11-7082, a specific and well documented pharmacologic inhibitor of NF-?B, and we observed that BAY 11-7082 effectively inhibits the acidic bile-induced gene expression profiling of the NF-?B signaling pathway (down-regulation of 72 out of 84 analyzed genes). NF-?B inhibition significantly prevents the acidic bile-induced transcriptional activation of NF-?B transcriptional factors, RELA (p65) and c-REL, as well as genes related to and commonly found in established HNSCC cell lines. These include anti-apoptotic bcl-2, oncogenic STAT3, EGFR, ?Np63, TNF-? and WNT5A, as well as cytokines IL-1? and IL-6. Our findings are consistent with our hypothesis demonstrating that NF-?B inhibition effectively prevents the acidic bile-induced cancer-related mRNA phenotype in normal human hypopharyngeal epithelial cells supporting an understanding that NF-?B may be a critical link between acidic bile and early preneoplastic events in this setting.
Project description:Bile reflux contributes to oesophageal injury and neoplasia. COX-2 is involved in both inflammation and carcinogenesis; however, the precise mechanisms by which bile acids promote COX-2 expression in the oesophagus are largely unknown. We analysed the molecular mechanisms that govern bile acid-mediated expression of COX-2 in Barrett's oesophagus and oesophageal adenocarcinoma (OA).The effects of bile acids on COX-2 expression were analysed in immortalised Barrett's oesophagus and OA cells using immunoblotting and transient transfections. Pharmacological inhibitors, phospho-specific antibodies, dominant-negative mutants and siRNA techniques were used to identify relevant signalling pathways. Flow cytometry and reactive oxygen species (ROS) scavengers were used to examine ROS involvement. Immunohistochemistry was performed on oesophageal mucosa obtained from an established rat model of bile reflux.Unconjugated bile acids potently stimulated COX-2 expression and induced AKT and ERK1/2 phosphorylation in concert with COX-2 induction. These findings were mimicked in the in vivo rat model. Dominant-negative (DN) AKT and LY294002 (PI3K inhibitor) or U0126 (MEK-1/2 inhibitor) blocked chenodeoxycholic acid (CD) and deoxycholic acid (DC) mediated COX-2 induction. CD and DC also induced CREB phosphorylation and AP-1 activity. CREB-specific siRNA and DN AP-1 blocked CD and DC-induced COX-2 induction. Finally, CD and DC increased intracellular ROS, while ROS scavengers blocked COX-2 induction and the signalling pathways involved.Unconjugated bile acids induce CREB and AP-1-dependent COX-2 expression in Barrett's oesophagus and OA through ROS-mediated activation of PI3K/AKT and ERK1/2. This study enhances our understanding of the molecular mechanisms by which bile acids promote the development of oesophageal adenocarcinoma.
Project description:<h4>Objective</h4>Besides reducing gastric acid secretion, proton pump inhibitors (PPIs) suppress Th2-cytokine-stimulated expression of an eosinophil chemoattractant (eotaxin-3) by esophageal epithelial cells through acid-independent, anti-inflammatory mechanisms. To explore acid-inhibitory and acid-independent, anti-inflammatory PPI effects in reducing esophageal eosinophilia, we studied eotaxin-3 expression by the proximal and distal esophagus of children with esophageal eosinophilia before and after PPI therapy. In vitro, we studied acid and bile salt effects on IL-13-stimulated eotaxin-3 expression by esophageal epithelial cells.<h4>Design</h4>Among 264 children with esophageal eosinophilia seen at a tertiary pediatric hospital from 2008 through 2012, we identified 10 with esophageal biopsies before and after PPI treatment alone. We correlated epithelial cell eotaxin-3 immunostaining with eosinophil numbers in those biopsies. In vitro, we measured eotaxin-3 protein secretion by esophageal squamous cells stimulated with IL-13 and exposed to acid and/or bile salt media, with or without omeprazole.<h4>Results</h4>There was strong correlation between peak eosinophil numbers and peak eotaxin-3-positive epithelial cell numbers in esophageal biopsies. Eotaxin-3 expression decreased significantly with PPIs only in the proximal esophagus. In esophageal cells, exposure to acid-bile salt medium significantly suppressed IL-13-induced eotaxin-3 secretion; omeprazole added to the acid-bile salt medium further suppressed that eotaxin-3 secretion, but not as profoundly as at pH-neutral conditions.<h4>Conclusion</h4>In children with esophageal eosinophilia, PPIs significantly decrease eotaxin-3 expression in the proximal but not the distal esophagus. In esophageal squamous cells, acid and bile salts decrease Th2 cytokine-stimulated eotaxin-3 secretion profoundly, possibly explaining the disparate PPI effects on the proximal and distal esophagus. In the distal esophagus, where acid reflux is greatest, a PPI-induced reduction in acid reflux (an effect that could increase eotaxin-3 secretion induced by Th2 cytokines) might mask the acid-independent, anti-inflammatory PPI effect of decreasing cytokine-stimulated eotaxin-3 secretion.
Project description:Cysteinyl leukotrienes contribute to Th2-type inflammatory immune responses. Their levels in oesophageal tissue, however, do not distinguish patients with eosinophilic oesophagitis (EoE) from controls.We asked whether mRNA levels of leukotriene C4 synthase (LTC4 S), a key regulator of leukotriene production, could serve as a marker for EoE.Digital mRNA expression profiling (nCounter(®) Technology) was performed on proximal and distal oesophageal biopsies of 30 paediatric EoE patients and 40 non-EoE controls. Expression data were confirmed with RT-qPCR. LTC4 S mRNA levels were quantified in whole blood samples. Leukotriene E4 was measured in urine.LTC4 S mRNA levels were elevated in proximal (2.6-fold, P < 0.001) and distal (2.9-fold, P < 0.001) oesophageal biopsies from EoE patients. Importantly, increased LTC4 S mRNA transcripts identified a subpopulation of EoE patients (28%). This patient subgroup had higher serum IgE levels (669 U/mL vs. 106 U/mL, P = 0.01), higher mRNA transcript numbers of thymic stromal lymphopoietin (TSLP) (1.6-fold, P = 0.009) and CD4 (1.4-fold, P = 0.04) but lower IL-23 mRNA levels (0.5-fold, P = 0.04). In contrast, elevated levels of IL-23 mRNA were found in oesophageal biopsies of patients with reflux oesophagitis. LTC4 S mRNA transcripts in whole blood and urinary excretion of leukotriene E4 were similar in EoE patient subgroups and non-EoE patients.Elevated oesophageal expression of LTC4 S mRNA is found in a subgroup of EoE patients, concomitant with higher serum IgE levels and an oesophageal transcriptome indicative of a more-pronounced allergic phenotype. Together with TSLP and IL-23 mRNA levels, oesophageal LTC4 S mRNA may facilitate diagnosis of an EoE subpopulation for personalized therapy.
Project description:OBJECTIVE:To compare the effects and tolerability of omeprazole and cisapride with that of placebo for control of heartburn in primary care patients. DESIGN:Randomised, double blind, placebo controlled study. SETTING:65 primary care practices in Norway. PARTICIPANTS:483 untreated patients with complaints of heartburn >/=3 days a week, with at most grade 1 reflux oesophagitis. INTERVENTIONS:Omeprazole 20 mg once daily, cisapride 20 mg twice daily, or placebo for 8 weeks. MAIN OUTCOME MEASURES:Adequate control of heartburn, defined as </=1 day of the past 7 days with no more than mild heartburn, after 4 weeks of treatment. RESULTS:In the all patients treated analysis, adequate control of heartburn was achieved in 71% of patients taking omeprazole, 22% taking cisapride, and 18% taking placebo after 4 weeks of treatment (omeprazole v cisapride and placebo, P<0.0001; cisapride v placebo, non-significant). Results were comparable in patients with or without reflux oesophagitis. In patients treated with omeprazole only, symptom control was achieved significantly more often in patients positive for Helicobacter pylori. Antacid use was 2-3 times greater in patients taking cisapride or placebo than in those taking omeprazole. Relief of non-reflux symptoms did not significantly differ between the three groups. Significantly more patients taking cisapride reported adverse events than those taking omeprazole or placebo. CONCLUSIONS:Omeprazole 20 mg once daily was highly effective in relieving heartburn whereas cisapride 20 mg twice daily was not significantly more effective than placebo.