Increased expression of cytokines and adhesion molecules in rat chronic esophagitis

Herbal Combination 'HAGE-101912' Ameliorates Gastroesophageal Reflux Disease in Rats

Background

Gastroesophageal reflux disease (GERD) is a chronic, relapsing disorder. In this era of modern and fast-track lifestyle and food habits, the incidence of GERD is rapidly increasing. Currently, proton pump inhibitors (PPIs) are the primary choice of treatment. However, the associated side effects and a high relapse rate give rise to the need to explore alternative therapies.

Objective

The study aimed to evaluate HAGE-101912, an herbal combination, in different experimental models of GERD.

Methods

Antacid activity was assessed based on H+/K+ATPase inhibitory activity of parietal cells using artificial gastric juice. Tonic contraction of the lower esophageal sphincter (LES) was evaluated using an AD Instrument. A GERD model of the pylorus and fundus ligation (preventive and curative models) in rats was selected to assess the efficacy of HAGE-101912 at a dose of 250 mg/kg body weight, and various parameters such as the gastric pH, gastric volume, total acidity, gross esophageal ulcer index, and histopathological changes were evaluated. The prokinetic activity was assessed using the phenol red method.

Results

HAGE-101912 increased the acid-neutralizing capacity (P < 0.001), decreased H+/K+ATPase activity (P < 0.01), and increased the contraction of the LES. In the preventive model, HAGE-101912 significantly reduced the gastric acid volume (P < 0.01), total acidity (P < 0.001), and gross esophageal ulcer index (P < 0.01); increased the gastric acid pH (P < 0.01); and protected the esophageal epithelium. In addition, HAGE-101912 increased gastric emptying and gastrointestinal transit through its prokinetic activity (P < 0.05).

Conclusion

HAGE-101912 has a beneficial effect in GERD as it effectively inhibits the H+/K+ATPase, increases the gastric pH, restores the LES function, protects the esophageal epithelium, and increases gastric emptying and transit.

Analysis of local expression of inflammatory cytokines genes in patients with gastroesophageal reflux disease and its association with types and number of gastroesophageal refluxes

The aim of the study was to evaluate gene expression of proinflammatory cytokines in esophageal mucosa in patients with erosive esophagitis (EE) and non-erosive form (NERD) of gastroesophageal reflux disease (GERD) and perform correlation analysis between the genes expression and types and number of gastroesophageal refluxes. Methods. This was a single-center prospective study. Esophageal mucosa samples were taken from lower part of the esophagus during endoscopy. Expression of IL-1b, IL-10, IL-18, TNFA, TLR4, GATA3, CD68 and beta-2 macroglobulin genes was assessed with ImmunoQuantex assays. Multichannel intraluminal esophageal pH-impedance studies were performed with Ohmega recorder and 2pH-6impedance catheters. Results. Data of 60 patients (females - 34; mean age (M±SD) 54.6 years, 20 - with erosive esophagitis) were available for the analysis. In those with EE, there was higher expression of IL-18 (5.89±0.4 vs 5.28±1.1, p=0.04), GATA3 (2.92±0.86 vs 2.23±0.96, p=0.03) genes, and inflammatory index (92.12±32.41% vs 70.1±30.8%, p=0.02) compared to NERD. Direct correlation was found between acid exposure time and expression of IL-1b (Spearman rank R = 0.29), IL-18 (R=0.31), TNFA (R=0.35), GATA3 (R=0.34), TLR4 (R=0.29), CD68 (R=0.37) genes and inflammatory index (R=0.3). Indirect correlation was revealed between mean рН and expressions of IL-18 (R= -0.28), TNFA (R= -0.33), GATA3 (R= -0.28), TLR4 (R= -0.28), CD68 (R= -0.39) genes and inflammatory index (R= -0.17). No correlation was found between the genes’ expression and number of gastroesophageal refluxes. Conclusions: Expression of proinflammatory cytokines’ genes differ in patients with EE and NERD. There is a correlation between expression of studied genes and esophageal acidity.

Local inflammatory response to gastroesophageal reflux: Association of gene expression of inflammatory cytokines with esophageal multichannel intraluminal impedance-pH data

BACKGROUND

Gene expression of inflammatory cytokines may take part in the pathophysiology of different forms of gastroesophageal reflux disease (GERD).

AIM

To explore gene expression of inflammatory cytokines in esophageal mucosa in patients with erosive esophagitis (EE) and non-erosive forms of GERD (NERD) and its association with data of esophageal multichannel intraluminal impedance-pH (MII-pH) measurements.

METHODS

This was a single-center prospective study. Esophageal mucosa samples were taken from the lower part of the esophagus during endoscopy. Expression of interleukin (IL)-1β, IL-10, IL-18, tumor necrosis factor α (TNFA), toll-like receptor 4 (TLR4), GATA binding protein 3 (GATA3), differentiation cluster 68 (CD68) and β-2 microglobulin genes in esophageal mucosa was assessed with ImmunoQuantex assays. MII-pH measurements were performed on all the participants. Diagnosis of GERD was confirmed by the results of the MII-pH data. Based on the endoscopy, patients were allocated to the groups of EE and NERD. The control group consisted of non-symptomatic subjects with normal endoscopy and MII-pH results. We used nonparametric statistics to compare the differences between the groups. Association of expression of the mentioned genes with the results of the MII-pH data was assessed with Spearman’s rank method.

RESULTS

Data from 60 patients with GERD and 10 subjects of the control group were available for the analysis. Higher expression of IL-18 (5.89 ± 0.4 vs 5.28 ± 1.1, P = 0.04) and GATA3 (2.92 ± 0.86 vs 2.23 ± 0.96, P = 0.03) was found in the EE group compared to NERD. Expression of IL-1β, IL-18, TNFA, and TLR4 was lower (P < 0.05) in the control group compared to EE and NERD. Esophageal acid exposure correlated with the expression of IL-1β (Spearman’s rank r = 0.29), IL-18 (r = 0.31), TNFA (r = 0.35), GATA3 (r = 0.34), TLR4 (r = 0.29), and CD68 (r = 0.37). Mean esophageal рН correlated inversely with the expression of IL-18, TNFA, GATA3, TLR4, and CD68. No association of gene expression with the number of gastroesophageal refluxes was found.

CONCLUSION

In patients with EE, local expression of IL-18 and GATA3 was higher compared to subjects with NERD. Esophageal acid exposure correlated directly with expression of IL-1β, IL-18, TNFA, TLR4, CD68, and β-2 microglobulin genes. Inverse correlation was revealed between expression of IL-18, TNFA, GATA3, TLR4, and CD68 and mean esophageal pH.

Candidate Drugs Screening for Behcet’s Disease Based on Bioinformatics Analysis and Mouse Experiments

Background

Behcet’s disease (BD) is a chronic immune disease that involves multiple systems. As the pathogenesis of BD is not clear, and new treatments are needed, we used bioinformatics to identify potential drugs and validated them in mouse models.

Methods

Behcet’s disease-related target genes and proteins were screened in the PubMed and UVEOGENE databases. The biological functions and pathways of the target genes were analyzed in detail by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. A protein-protein interaction (PPI) network was constructed by the STRING database, and hub genes were identified by the Cytoscape plug-in CytoHubba. Gene-drug interactions were identified from the DGIdb database. Experimental autoimmune uveitis (EAU) mice were used as an animal model for drug validation.

Results

A total of 249 target genes and proteins with significant differences in BD were screened, and the results of functional enrichment analysis suggested that these genes and proteins were more located on the cell membrane, involved in regulating the production of cytokines and affecting the activity of cytokines. They mainly regulated “Cytokine- Cytokine receptor interaction”, “Inflammatory bowel disease (IBD)” and “IL-17 signaling Pathway”. In addition, 10 hub genes were obtained through PPI network construction and CytoHubba analysis, among which the top 3 hub genes were closely related to BD. The DGIdb analysis enriched seven drugs acting together on the top 3 hub genes, four of which were confirmed for the treatment of BD or its complications. There is no evidence in the research to support the results in omeprazole, rabeprazole, and celastrol. However, animal experiments showed that rabeprazole and celastrol reduced anterior chamber inflammation and retinal inflammation in EAU mice.

Conclusions

The functional analysis of genes and proteins related to BD, identification of hub genes, and validation of potential drugs provide new insights into the disease mechanism and potential for the treatment of BD.

Mucosal pathogenesis in gastro-esophageal reflux disease

BACKGROUND

Despite gastro-esophageal reflux disease affecting up to 20% of Western populations, relatively little is known about the molecular mechanisms underlying its most troublesome symptom: heartburn. Recent findings have unveiled the role of components of the esophageal mucosa in the pathogenesis of GERD including sensory nociceptive nerves and inflammatory mediators. Erosive esophagitis was long believed to develop as a result of acid injury at the esophageal lumen, but novel concepts suggest the generation of reflux-induced esophageal injury as a result of cytokine-mediated inflammation. Moreover, the localization and characterization of mucosal afferent nerves vary between GERD phenotypes and could explain the heterogeneity of symptom perception between patients who experience similar levels of acid reflux.

PURPOSE

The purpose of this review is to consider the crosstalk of different factors of the esophageal mucosa in the pathogenesis of GERD, with a particular focus on mucosal innervation and molecular basis of acid-induced cytokine response. We discuss the current understanding of the mucosal response to acid injury, the nociceptive role of acid-sensitive receptors expressed in the esophageal mucosa, and the role of esophageal epithelial cells in initiating the onset of erosive esophagitis.

Evidence for Cytoprotective Effect of Carbon Monoxide Donor in the Development of Acute Esophagitis Leading to Acute Esophageal Epithelium Lesions

Exposure to acidic gastric content due to malfunction of lower esophageal sphincter leads to acute reflux esophagitis (RE) leading to disruption of esophageal epithelial cells. Carbon monoxide (CO) produced by heme oxygenase (HMOX) activity or released from its donor, tricarbonyldichlororuthenium (II) dimer (CORM-2) was reported to protect gastric mucosa against acid-dependent non-steroidal anti-inflammatory drug-induced damage. Thus, we aimed to investigate if CO affects RE-induced esophageal epithelium lesions development. RE induced in Wistar rats by the ligation of a junction between pylorus and forestomach were pretreated i.g. with vehicle CORM-2; RuCl₃; zinc protoporphyrin IX, or hemin. CORM-2 was combined with NG-nitro-L-arginine (L-NNA), indomethacin, capsazepine, or capsaicin-induced sensory nerve ablation. Esophageal lesion score (ELS), esophageal blood flow (EBF), and mucus production were determined by planimetry, laser flowmetry, histology. Esophageal Nrf-2, HMOXs, COXs, NOSs, TNF-α and its receptor, IL-1 family and IL-1 receptor antagonist (RA), NF-κB, HIF-1α, annexin-A1, suppressor of cytokine signaling (SOCS3), TRPV1, c-Jun, c-Fos mRNA/protein expressions, PGE₂, 8-hydroxy-deoxyguanozine (8-OHdG) and serum COHb, TGF-β1, TGF-β2, IL-1β, and IL-6 content were assessed by PCR, immunoblotting, immunohistochemistry, gas chromatography, ELISA or Luminex platform. Hemin or CORM-2 alone or combined with L-NNA or indomethacin decreased ELS. Capsazepine or capsaicin-induced denervation reversed CORM-2 effects. COHb blood content, esophageal HMOX-1, Nrf-2, TRPV1 protein, annexin-A1, HIF-1α, IL-1 family, NF-κB, c-Jun, c-Fos, SOCS3 mRNA expressions, and 8-OHdG levels were elevated while PGE₂ concentration was decreased after RE. CO donor-maintained elevated mucosal TRPV1 protein, HIF-1 α, annexin-A1, IL-1RA, SOCS3 mRNA expression, or TGF-β serum content, decreasing 8-OHdG level, and particular inflammatory markers expression/concentration. CORM-2 and Nrf-2/HMOX-1/CO pathway prevent esophageal mucosa against RE-induced lesions, DNA oxidation, and inflammatory response involving HIF-1α, annexin-A1, SOCS3, IL-1RA, TGF-β-modulated pathways. Esophagoprotective and hyperemic CO effects are in part mediated by afferent sensory neurons and TRPV1 receptors activity with questionable COX/PGE₂ or NO/NOS systems involvement.

Interleukin-1β Enhances Umbilical Cord Mesenchymal Stem Cell Adhesion Ability on Human Umbilical Vein Endothelial Cells via LFA-1/ICAM-1 Interaction

The migration of administered mesenchymal stem cells (MSCs) to sites of injury via the bloodstream has been demonstrated. However, the underlying mechanisms of umbilical cord MSC adhesion to endothelial cells during transendothelial migration are still unclear. In this study, our data showed that IL-1β induced LFA-1 expression on MSCs and ICAM-1 expression on HUVECs. We then pretreated MSCs with protein synthesis inhibitor cycloheximide. The results showed that IL-1β induced LFA-1 expression on the surface of MSCs via the protein synthesis pathway. Through the p38 MAPK signaling pathway inhibitor SB 203580, we found that IL-1β induces the expression of LFA-1 through p38 MAPK signaling and enhances ICAM-1 expression in HUVECs. In addition, IL-1β-induced MSC adhesion to HUVECs was found to be inhibited by IL-1RA and the LFA-1 inhibitor lovastatin. These results indicate that IL-1β promotes the cell adhesion of MSCs to HUVECs through LFA-1/ICAM-1 interaction. We address the evidence that the cell adhesion mechanism of IL-1β promotes MSC adhesion to HUVECs. The implications of these findings could enhance the therapeutic potential of MSCs.

Melatonin in Prevention of the Sequence from Reflux Esophagitis to Barrett's Esophagus and Esophageal Adenocarcinoma: Experimental and Clinical Perspectives

Melatonin is a tryptophan-derived molecule with pleiotropic activities which is produced in all living organisms. This "sleep" hormone is a free radical scavenger, which activates several anti-oxidative enzymes and mechanisms. Melatonin, a highly lipophilic hormone, can reach body target cells rapidly, acting as the circadian signal to alter numerous physiological functions in the body. This indoleamine can protect the organs against a variety of damaging agents via multiple signaling. This review focused on the role played by melatonin in the mechanism of esophagoprotection, starting with its short-term protection against acute reflux esophagitis and then investigating the long-term prevention of chronic inflammation that leads to gastroesophageal reflux disease (GERD) and Barrett's esophagus. Since both of these condition are also identified as major risk factors for esophageal carcinoma, we provide some experimental and clinical evidence that supplementation therapy with melatonin could be useful in esophageal injury by protecting various animal models and patients with GERD from erosions, Barrett's esophagus and neoplasia. The physiological aspects of the synthesis and release of this indoleamine in the gut, including its release into portal circulation and liver uptake is examined. The beneficial influence of melatonin in preventing esophageal injury from acid-pepsin and acid-pepsin-bile exposure in animals as well as the usefulness of melatonin and its precursor, L-tryptophan in prophylactic and supplementary therapy against esophageal disorders in humans, are also discussed.

A novel murine model of esophageal nonerosive reflux disease: from inflammation to impairment in mucosal integrity

Nonerosive reflux disease (NERD) is a highly prevalent phenotype of the gastroesophageal reflux disease. In this study, we developed a novel murine model of NERD in mice with microscopic inflammation and impairment in the epithelial esophageal barrier. Female Swiss mice were subjected to the following surgical procedure: the transitional region between the forestomach and the glandular portion of the stomach was ligated, and a nontoxic ring was placed around the duodenum near the pylorus. The control group underwent sham surgery. The animals were euthanized at 1, 3, 7, and 14 days after surgery. Survival and body weight were monitored daily. Esophageal wet weight, macroscopic lesion, histopathological alterations, myeloperoxidase (MPO) activity, cytokine levels, transepithelial electrical resistance (TEER), and mucosal permeability were evaluated. The survival rate was 78% at 14 days, with mild loss in body weight. Surgery did not induce erosive esophagitis but instead induced microscopic inflammation and increased esophageal wet weight, IL-6, keratinocyte-derived cytokine (KC) levels, and MPO activity with maximal peak between 3 and 7 days and resolution at 14 days postsurgery. Epithelial esophageal barrier was evaluated in operated mice at 7 and 14 days postsurgery; a decrease in TEER and increase in the esophageal epithelial permeability were observed compared with the sham-operated group. In addition, the inhibition of acid secretion with omeprazole significantly prevented the esophageal inflammation and impairment of barrier function at 7 days postsurgery. Thus we established a novel experimental model of NERD in mice, which can contribute to understanding the pathophysiological events associated with NERD.NEW & NOTEWORTHY In this study, we standardized an experimental model of nonerosive reflux disease (NERD) in mice. This model involves an acute inflammatory response followed by impaired esophageal mucosal integrity, even in the absence of inflammation. Thus this model can serve for evaluation of pathophysiological aspects of NERD and open new perspectives for therapeutic strategies for patients with this disorder.

Association of medications for lifestyle-related diseases with reflux esophagitis

BACKGROUND

Because of a change in lifestyle, especially adoption of westernized eating habits, lifestyle-related diseases have become increasingly prevalent. The aim of this study was to investigate the association of medications for lifestyle-related diseases with reflux esophagitis (RE).

METHODS

We conducted a hospital-based, cross-sectional retrospective study of consecutive outpatients who received an upper gastrointestinal endoscopy in our department from February 2008 to November 2014, which was performed by one specialist who was a member of the Japan Gastroenterological Endoscopy Society. We investigated the patient profile, Helicobacter pylori (H. pylori) infection status, medications for lifestyle-related diseases (including calcium channel blockers, statins, and bisphosphonates), and upper gastrointestinal endoscopic findings (RE, hiatal hernia, Barrett's mucosa, and endoscopic gastric mucosal atrophy [EGA]). Patients with gastrectomy, peptic ulcer disease, gastric or esophageal malignant disease, and those who used proton pump inhibitors or histamine-2 receptor antagonists were excluded. We divided the subjects into a group without RE (RE(-)) and a RE (RE(+)) group as judged by endoscopy, and investigated the risk factors for RE.

RESULTS

Of 1,744 consecutive cases, 590 cases (300 males and 290 females; mean age 60.5±13.2 years) were eligible. RE(-) and RE(+) cases numbered 507 and 83, respectively. Bivariate analysis showed significant positive associations of RE with male sex, body mass index (BMI), calcium channel blockers, Barrett's mucosa, hiatal hernia and negative associations of RE with H. pylori positivity, EGA. Multivariate analysis showed significant positive associations of RE with BMI (odds ratio [OR]: 1.20, 95% confidence interval [95% CI]: 1.10-1.29), use of calcium channel blockers (OR: 2.12, 95% CI: 1.16-3.87), Barrett's mucosa (OR: 2.97, 95% CI: 01.64-5.38), hiatal hernia (OR: 3.13, 95% CI: 1.79-5.47) and negative associations of RE with H. pylori positivity (OR: 0.20, 95% CI: 0.07-0.57), use of statins (OR: 0.42, 95% CI: 0.18-0.96), and EGA (OR: 0.83, 95% CI: 0.70-0.98).

CONCLUSION

Calcium channel blockers were positively associated with RE and statins were negatively associated with RE, while bisphosphonates were not associated with RE.

Interferon γ-Induced Nuclear Interleukin-33 Potentiates the Release of Esophageal Epithelial Derived Cytokines

Background

Esophageal epithelial cells are an initiating cell type in esophageal inflammation, playing an essential role in the pathogenesis of gastroesophageal reflux disease (GERD). A new tissue-derived cytokine, interleukin-33 (IL-33), has been shown to be upregulated in esophageal epithelial cell nuclei in GERD, taking part in mucosal inflammation. Here, inflammatory cytokines secreted by esophageal epithelial cells, and their regulation by IL-33, were investigated.

Methods

In an in vitro stratified squamous epithelial model, IL-33 expression was examined using quantitative RT-PCR, western blot, ELISA, and immunofluorescence. Epithelial cell secreted inflammatory cytokines were examined using multiplex flow immunoassay. IL-33 was knocked down with small interfering RNA (siRNA) in normal human esophageal epithelial cells (HEECs). Pharmacological inhibitors and signal transducers and activators of transcription 1 (STAT1) siRNA were used to explore the signaling pathways.

Results

Interferon (IFN)γ treatment upregulated nuclear IL-33 in HEECs. Furthermore, HEECs can produce various inflammatory cytokines, such as IL-6, IL-8, monocyte chemoattractant protein 1 (MCP-1), regulated on activation normal T-cell expressed and presumably secreted (RANTES), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in response to IFNγ. Nuclear, but not exogenous IL-33, amplified IFN induction of these cytokines. P38 mitogen-activated protein kinase (MAPK) and janus protein tyrosine kinases (JAK)/STAT1 were the common signaling pathways of IFNγ-mediated induction of IL-33 and other cytokines.

Conclusions

Esophageal epithelial cells can actively participate in GERD pathogenesis through the production of various cytokines, and epithelial-derived IL-33 might play a central role in the production of these cytokines.

Alterations in junctional proteins, inflammatory mediators and extracellular matrix molecules in eosinophilic esophagitis

Eosinophilic esophagitis (EoE), an inflammatory atopic disease of the esophagus, causes massive eosinophil infiltration, basal cell hyperplasia, and sub-epithelial fibrosis. To elucidate cellular and molecular factors involved in esophageal tissue damage and remodeling, we examined pinch biopsies from EoE and normal pediatric patients. An inflammation gene array confirmed that eotaxin-3, its receptor CCR3 and interleukins IL-13 and IL-5 were upregulated. An extracellular matrix (ECM) gene array revealed upregulation of CD44 & CD54, and of ECM proteases (ADAMTS1 & MMP14). A cytokine antibody array showed a marked decrease in IL-1α and IL-1 receptor antagonist and an increase in eotaxin-2 and epidermal growth factor. Western analysis indicated reduced expression of intercellular junction proteins, E-cadherin and claudin-1 and increased expression of occludin and vimentin. We have identified a number of novel genes and proteins whose expression is altered in EoE. These findings provide new insights into the molecular mechanisms of the disease.

Platelet-activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non-erosive reflux disease patients and controls

BACKGROUND

A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls.

METHODS

Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3-week washout from PPI or H(2) antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex enzyme-linked immunosorbent assay for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet-activating factor (PAF).

KEY RESULTS

Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α (MIP-1α), and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable with healthy controls.

CONCLUSIONS & INFERENCES

Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients' mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.

Platelet-activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non-erosive reflux disease patients and controls

BACKGROUND

A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls.

METHODS

Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3-week washout from PPI or H(2) antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex enzyme-linked immunosorbent assay for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet-activating factor (PAF).

KEY RESULTS

Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α (MIP-1α), and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable with healthy controls.

CONCLUSIONS & INFERENCES

Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients' mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.

Gastro-oesophageal reflux disease is associated with up-regulation of desmosomal components in oesophageal mucosa

AIMS

Gastro-oesophageal reflux disease (GERD) is associated with impaired epithelial barrier function. This study was aimed at investigating the role of desmosomal proteins in relation to GERD.

METHODS AND RESULTS

Ninety-five patients with GERD-related symptoms (erosive, n = 51; non-erosive, n = 44) and 27 patients lacking those symptoms were included. Endoscopic and histological characterization of oesophagitis was performed according to the Los Angeles and Ismeil-Beigi criteria, respectively. Multiple biopsies were taken from the oesophageal mucosa of each patient. Gene expression analysis of plakoglobin, desmoglein-1, desmoglein-2 and desmoglein-3 was performed by quantitative real time (RT)-polymerase chain reaction and immunohistochemistry in the oesophageal mucosa. Routine histology revealed specific GERD-related alterations, such as dilatation of intercellular spaces (DIS), basal cell hyperplasia (BCH), and elongation of the papillae, in the oesophageal mucosa of patients with GERD, as compared with controls (all parameters: P < 0.05). All four genes and corresponding proteins were found to be up-regulated by between 1.7 and 8.1-fold (transcript level, P < 0.05; protein level, P < 0.05). Induced gene expression levels of plakoglobin, desmoglein-1 and desmoglein-2 correlated significantly with DIS and BCH.

CONCLUSIONS

Taken together, the uniform up-regulation of desmosomal genes/proteins in the oesophageal mucosa of patients with GERD supports the concept of architectural and molecular changes in the desmosomal compartment in the pathogenesis of GERD.

NcoI TNF-β gene polymorphism and TNF expression are associated with an increased risk of developing Barrett's esophagus and esophageal adenocarcinoma

OBJECTIVE

Esophageal cancer development is a sequence that starts with reflux esophagitis (RE), followed by Barrett's esophagitis (BE), dysplasia, and finally esophageal adenocarcinoma (EAC). Tumor necrosis factor (TNF) is a potent anti-neoplastic agent, hence DNA polymorphisms that reduce TNF levels potentially enhance the development of BE and EAC. The aim of the study was to determine the impact of TNF gene variation on the RE-BE-EAC cascade.

METHODS

DNA from 887 Caucasian participants (197 controls, 305 RE, 257 BE, 128 EAC) was tested for the gene polymorphism TNF-β NcoI, and TNF production was determined by TNF-α specific immunohistochemistry on esophageal biopsies from these BE (n = 31) and EAC (n = 4) patients.

RESULTS

As compared with healthy controls, the TNF-β NcoI A/A genotype was significantly more prevalent in BE (p = 0.04) and EAC patients (p = 0.02), but not in RE patients (p = 0.1). While TNF-α protein levels were invariably high in esophageal biopsies from EAC patients, most esophageal BE samples showed low to moderate TNF levels.

CONCLUSIONS

Chronic inflammation, like in BE, markedly increase the risk of malignant transformation. In this study, the significantly higher frequency of the TNF-β NcoI A/A genotype and the local TNF expression indicate that the pro-inflammatory cytokine TNF plays a role in the development of BE and EAC.

Cox2 and β-catenin/T-cell factor signaling intestinalize human esophageal keratinocytes when cultured under organotypic conditions

The incidence of esophageal adenocarcinoma (EAC) is rising in the United States. An important risk factor for EAC is the presence of Barrett esophagus (BE). BE is the replacement of normal squamous esophageal epithelium with a specialized columnar epithelium in response to chronic acid and bile reflux. However, the emergence of BE from squamous keratinocytes has not yet been demonstrated. Our research has focused on this. Wnt and cyclooxygenase 2 (Cox2) are two pathways whose activation has been associated with BE and progression to EAC, but their role has not been tested experimentally. To explore their contribution, we engineered a human esophageal keratinocyte cell line to express either a dominant-active Wnt effector CatCLef or a Cox2 complementary DNA. In a two-dimensional culture environment, Cox2 expression increases cell proliferation and migration, but neither transgene induces known BE markers. In contrast, when these cells were placed into three-dimensional organotypic culture conditions, we observed more profound effects. CatCLef-expressing cells were more proliferative, developed a thicker epithelium, and upregulated Notch signaling and several BE markers including NHE2. Cox2 expression also increased cell proliferation and induced a thicker epithelium. More importantly, we observed cysts form within the epithelium, filled with intestinal mucins including Muc5B and Muc17. This suggests that Cox2 expression in a three-dimensional culture environment induces a lineage of mucin-secreting cells and supports an important causal role for Cox2 in BE pathogenesis. We conclude that in vitro modeling of BE pathogenesis can be improved by enhancing Wnt signaling and Cox2 activity and using three-dimensional organotypic culture conditions.

Association of low serum adiponectin levels with erosive esophagitis in men: an analysis of 2405 subjects undergoing physical check-ups

BACKGROUND

Obesity is a risk factor for gastro-esophageal reflux disease (GERD). It is generally considered that intra-abdominal pressure in obese subjects is involved in the pathogenesis of GERD through acid exposure to the esophagus. Recently, visceral fat has been recognized as an endocrine organ that secretes various adipocytokines including adiponectin. The aim of this study was to elucidate the relation between adiponectin and erosive esophagitis.

METHODS

This was a cross-sectional retrospective observational study: 2405 consecutive subjects who underwent screening esophago-gastro-duodenoscopy with serum adiponectin measurement as part of their physical check-up programs were analyzed. Clinical factors were compared between subjects with and without erosive esophagitis. The association between adiponectin and erosive esophagitis was assessed using a bootstrapping re-sampling method after adjustment for factors that tended to be different in univariate analysis.

RESULTS

Serum adiponectin levels were significantly lower in those with erosive esophagitis (8.17 μg/ml) than in those without (10.1). The erosive esophagitis group had a greater body mass index (BMI) and waist circumference (WC) and a higher prevalence of hiatal hernia. Using the bootstrap method, with a lower adiponectin cut-off value of 3-7 μg/ml, the lower limit of the 95% confidence interval of the adjusted odds ratio consistently exceeded 1 after adjustment for BMI and hiatal hernia in men. When adjusting for WC instead of BMI, the effect of adiponectin was reduced but remained significant at a lower cut-off value (3-3.5 μg/ml).

CONCLUSIONS

Low serum adiponectin levels may be associated with an increased risk for erosive esophagitis in men.

Gastroesophageal reflux disease--from reflux episodes to mucosal inflammation

Gastroesophageal reflux disease (GERD) affects 20-30% of the population in Western countries, and is one of the most common clinical problems in daily practice. GERD-associated functional and structural abnormalities are caused by recurrent exposure of the esophagus to acidic and nonacidic refluxate of gastric contents (containing duodenal and intestinal proteases as well as acid and gastric pepsin) from the stomach. Major progress has been made in the understanding of the molecular pathogenesis of GERD-associated mucosal inflammation, suggesting a complex and multifactorial pathogenesis and immune-mediated effects. This Review summarizes the complexity of mucosal pathogenesis, including microscopic changes, mucosal inflammation and GERD-specific molecular mediators, in the context of the clinical features and pathophysiological characteristics of GERD. The abnormal exposure of the esophagus to luminal contents leads to chronic mucosal inflammation that is characterized by the release of IL-8 specifically, as well as other proinflammatory mediators, from the esophageal mucosa. Evidence from animal studies indicates a stepwise inflammatory response by the epithelium, which attracts immune effector cells to infiltrate the mucosa. From bench to bedside, these novel molecular findings might provide new treatment options beyond current acid-suppressive therapy and the principle of inhibition of transient lower esophageal sphincter relaxation.

Analysing the role of COX-2 in acute oesophagitis and in melatonin-exerted protection against experimental reflux oesophagitis in rats†

Objectives

Cyclooxygenase(COX)-2 is implicated in variety of pathophysiological processes, although its role in acute reflux oesophagitis is debatable. This study was designed to evaluate the role of COX-2 during oesophagitis and in melatonin-elicited protection in rats.

Methods

Reflux oesophagitis was induced in rats by ligating the pyloric end and the limiting ridge of the stomach for 5 h. Celecoxib (COX-2 blocker; 10 mg/kg), 16,16-dimethyl prostaglandinE2 (dmPGE2; a synthetic analogue of PGE2; 10 µg/kg), melatonin (20 and 40 mg/kg) and omeprazole (10 mg/kg) were given intra-peritoneally 45 min before induction of oesophagitis in rats. Alterations in COX-1 and 2 gene expression and protein levels level were analysed via RT-PCR and Western blotting, respectively. Mucosal PGE2 level and myeloperoxidase (MPO) activity were measured using an enzyme immunoassay (EIA) kit and spectrophotometrically, respectively.

Key findings

COX-2 over-expression during reflux oesophagitis promotes inflammation of the oesophagus as celecoxib pretreatment significantly reduced tissue damage and MPO activity in rats with reflux oesophagitis (RE-rats). By contrast, dmPGE2 pretreatment significantly exacerbated tissue injury and simultaneously increased COX-2 expression, PGE2 levels and MPO activity in RE-rats. Further, melatonin pretreatment significantly reduced the tissue injury, COX-2 over-expression, PGE2 level and MPO activity in RE-rats. Melatonin offered more potent suppression of COX-2, PGE2 and MPO activity than the proton-pump inhibitor omeprazole; however, both reduced the lesion injury to a similar extent. Melatonin at a dose of 20 mg/kg failed to inhibit significantly the dmPGE2-induced tissue damage, COX-2 expression, PGE2 level and MPO activity in RE-rats while at a higher dose of 40 mg/kg it significantly attenuated these changes.

Conclusion

Our results suggest that COX-2 plays an important pro-inflammatory role during acute reflux oesophagitis in rats and its inhibition contributes significantly to melatonin-exerted protection against reflux oesophagitis.

Effect of different doses of GLP-2 (Teduglutide) on acute esophageal lesion due to acid-pepsin perfusion in male rats

Gastro-esophageal reflux currently is widespread disorders with dangerous complications. GLP-2 is a peptide that has trophic and anti-inflammatory effects on gastrointestinal mucosa. The aim of this study was to evaluate the protective role of GLP-2 in esophageal mucosa lesion due to perfusion acid-pepsin. Thirty-six male rats were used in this study and divided into six groups. They were control, acid-pepsin, GLP-2 20 μg, GLP-2 30 μg, GLP-2 40 μg and GLP-2 50 μg/kg groups. Esophageal blood flow, plasma NO metabolite, esophageal tissue NO metabolites and histological study of esophagus were performed as indicators of esophageal damage following acid-pepsin perfusion. Results showed that GLP-2 significantly increased plasma and tissue NO metabolites in comparison to acid-pepsin group. Also histological study showed significantly fewer lesions in the most effective dose GLP-2 30 μg in comparison to acid-pepsin group, our results show that GLP-2 could be useful for the treatment of esophageal in animal model.

Inflammation and oxidative stress in gastroesophageal reflux disease

The etiology of esophageal mucosal injury is complex, since it may involve the reflux of gastric acid, bile acid, and pancreatic juice, external factors such as drugs and alcohol, or functional factors such as esophagogastric motility. The mechanism of esophageal mucosal injury has gradually been understood at the molecular biological level. It is particularly important that pro-inflammatory factors, such as inflammatory cytokines (interleukin-6 and -8), leukocytes and oxidative stress, have been demonstrated to be involved in the development of gastroesophageal reflux disease (GERD) including nonerosive reflux disease (NERD). In addition, nociceptors such as acid-sensitive vanilloid receptors, protease-activated receptors and substance P have also been implicated in the pathogenesis of neurogenic inflammation in NERD patients with esophageal hypersensitivity. The development of new therapy with anti-inflammatory and anti-oxidant effects is expected to assist in the treatment of intractable NERD/GERD and the prevention of carcinogenesis.

Role of Th-2 cytokines in the development of Barrett's esophagus in rats

BACKGROUND

Barrett's esophagus is characterized by a distinct Th-2-predominant cytokine profile, unlike the pro-inflammatory nature of reflux esophagitis. The aim of this study was to examine the role of Th-2 cytokines during the development of Barrett's esophagus, using a rat model.

METHODS

Barrett's esophagus was induced by Levrat's esophagojejunostomy technique in Brown-Norway (BN) rats. Rats were killed at 8, 15, 30, and 50 weeks after the operation. We studied the incidences of esophagitis and Barrett's esophagus, and the mRNA expression of cytokines and CDX2 by real-time reverse transcriptase-polymerase chain reaction and immunohistochemical staining. Finally, we compared the incidence of Barrett's esophagus in BN rats with that in Sprague-Dawley (SD) rats.

RESULTS

Esophagitis was found in all rats. Barrett's esophagus appeared 8 weeks after the operation, and its incidence and length increased over time. Levels of Th-2 cytokines such as interleukin (IL)-4, IL-10, and IL-13 were significantly increased in Barrett's esophagus as compared to those in non-Barrett's esophagus, while there were no differences in the levels of pro-inflammatory cytokines. The peak of elevated IL-4 mRNA was observed before that of CDX2 mRNA. IL-4 was co-localized in CD4-positive cells and CDX2-positive goblet cells. The incidence of Barrett's esophagus was more common in BN rats (8/10, 80%) than in SD rats (2/7, 28%) at 30 weeks.

CONCLUSION

Th-2 cytokines, especially IL-4, may play a crucial role in the development of Barrett's esophagus in an early phase. These results provide understanding of the pathogenesis of Barrett's esophagus from the aspect of the Th-2 immune response.

Establishment of a reflux esophago-laryngitis model in rats

BACKGROUND

To investigate the pathophysiology of reflux laryngitis, an experimental model is required.

AIM

The aim of this study is to establish an animal model of reflux esophago-laryngitis, modifying our previously reported model of chronic acid reflux esophagitis.

METHODS

The modified chronic acid reflux esophagitis (m-RE) group (n = 10), in which the duodenum was wrapped with 2.5 mm of Nelaton catheter, was not treated with any drugs. Also postoperatively, two treatment groups (n = 10 in each) received different dosages of rabeprazole (RPZ): 1.0 mg/kg/day (RPZ 1.0 group) or 10.0 mg/kg/day (RPZ 10.0 group). As a control group (n = 5), other rats underwent sham operation. The esophagus and larynx were resected on day 14 after the operation, and ulcer score of the esophagus was assessed. The epithelial thickness and leukocyte infiltration of the supraglottic and subglottic laryngeal mucosae were investigated. The number of interleukin (IL)-1β-positive cells was also counted and defined as the IL-1β labeling index.

RESULTS

In the m-RE group, the epithelial thickness, leukocyte infiltration, and IL-1β labeling index of the supraglottic and subglottic laryngeal mucosae were increased compared with controls (P < 0.01). In the RPZ groups, not only the ulcer score of esophagus but also the epithelial thickness, leukocyte infiltration, and IL-1β labeling index of both the supraglottic and subglottic laryngeal mucosae were decreased dose-dependently relative to the m-RE group (P < 0.05).

CONCLUSIONS

Our modified chronic acid reflux esophagitis model proved useful in establishing a rat reflux esophago-laryngitis model, with both pathological laryngeal findings and reflux esophagitis shown to be improved by administration of a proton pump inhibitor.

Secretory phospholipase A2 inhibition attenuates intercellular adhesion molecule-1 expression in human esophageal adenocarcinoma cells

BACKGROUND

Esophageal adenocarcinoma is an aggressive malignancy, with most patients succumbing to metastatic disease. The presence of intercellular adhesion molecule-1 (ICAM-1) in these cancer cells contributes to their metastatic potential. The ICAM-1 production in other cell types is stimulated by the actions of phospholipase enzymes. We hypothesize that inhibition of the enzyme secretory phospholipase A2 (sPLA2), which contributes to the growth potential of normal esophageal mucosa and esophageal cancer cells, may attenuate ICAM-1 production and nuclear factor-kappa beta activation in human esophageal adenocarcinoma cells.

METHODS

The FLO-1 verified human esophageal adenocarcinoma cells were treated with 5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino) pentanoic acid, a specific inhibitor of group IIa sPLA2 (5 μM, 10 μM, and 15 μM doses), followed by tumor necrosis factor-alpha stimulation (20 ng/mL). Cells and medium were collected and analyzed by immunoblotting, flow cytometry, and enzyme-linked immunosorbent assay. Statistical analysis was performed using analysis of variance with the Fisher's least significant difference post-hoc test.

RESULTS

Treatment with sPLA2 inhibitor attenuated total cellular ICAM-1 expression in a dose-dependent manner (p<0.005). Cell-surface and secreted ICAM-1 expression decreased significantly with sPLA2 inhibitor treatment (p<0.001 and p<0.05, respectively). sPLA2 inhibition attenuated nuclear factor-kappa beta activation dose-dependently (p<0.05).

CONCLUSIONS

Esophageal adenocarcinoma has significant metastatic potential, and inhibiting its metastasis would significantly advance the treatment of this disease. We demonstrate here that treatment of human esophageal adenocarcinoma cells with sPLA2 inhibitor attenuates the expression of ICAM-1, a marker of metastatic potential, and nuclear factor-kappa beta activation, suggesting a common pathway between the two. These findings identify inhibition of sPLA2 as a potential therapeutic target for esophageal adenocarcinoma.

Inflammatory mediators in gastroesophageal reflux disease: impact on esophageal motility, fibrosis, and carcinogenesis

Gastroesophageal reflux disease (GERD) is one of the most common problems in clinical practice today. It is widely believed that functional and structural abnormalities of the gastroesophageal junction as well as an abnormal exposure to gastroduodenal contents are the main contributors to its pathogenesis. Novel findings of the inflammatory process in GERD suggest a far more complex process involving multifaceted inflammatory mechanisms. This review summarizes knowledge about the expression of inflammatory mediators in GERD and their potential cellular sources and provides an integrated concept of disease pathogenesis. In addition we evaluate the contribution of inflammatory mediators to well-known complications of GERD, namely motility abnormalities, fibrosis, and carcinogenesis. Novel findings regarding the pathophysiology of esophageal inflammation should enhance our understanding of GERD and its complications and provide new treatment insights.

Gastroesophageal reflux might cause esophagitis through a cytokine-mediated mechanism rather than caustic acid injury

BACKGROUND & AIMS

Reflux esophagitis is believed to be caused by the caustic effects of refluxed gastric acid on esophageal epithelial cells. However, caustic chemical injuries develop rapidly whereas esophagitis might not appear until weeks after the induction of reflux in animal models. We studied early histologic events in the development of reflux esophagitis in a rat model and performed in vitro experiments to determine whether exposure to acidified bile salts causes esophageal epithelial cells to secrete chemokines that might contribute to inflammation.

METHODS

At various time points after esophagoduodenostomy, the rat esophagus was removed and inflammatory changes were analyzed by histologic analyses. Human esophageal squamous cell lines were exposed to acidified bile salts to evaluate their effects on cytokine production and immune-cell migration.

RESULTS

Reflux esophagitis started at postoperative day 3 with lymphocytic infiltration of the submucosa that progressed to the epithelial surface-these findings contradicted those expected from a caustic chemical injury. Basal cell and papillary hyperplasia preceded the development of surface erosions. Exposure of squamous cells to acidified bile salts significantly increased the secretion of interleukin-8 and interleukin-1beta; conditioned media from these cells caused significant increases in the migration rates of T cells and neutrophils.

CONCLUSIONS

These findings support, but do not prove, an alternative concept for the development of reflux esophagitis in which refluxed gastric juice does not directly damage the esophagus, but rather stimulates esophageal epithelial cells to secrete chemokines that mediate damage of esophageal tissue.

Interleukin-6, desmosome and tight junction protein expression levels in reflux esophagitis-affected mucosa

AIM: To investigate the correlation between the expression levels of interleukin (IL)-6 and proteins in tight junctions (TJs) in the esophageal mucosa of rats modeling different types of reflux esophagitis (RE), and the ability of aluminum phosphate to protect against RE-induced mucosal damage via these proteins.

METHODS: Male SPF Wistar rats aged 56 d were divided randomly into acid RE, alkaline RE, mixed RE, and control groups. Various surgical procedures were performed to establish rat models of acid RE. At 14 d after the procedure, some of the rats started aluminum phosphate treatment. Transmission electron microscopy (TEM) was used to observe the morphological features of TJs and desmosomes in the esophageal epithelium. Immunohistochemical methods and Western blotting were used to measure expression of claudin 1, occludin, ZO-1, JAM-1, DSG-1 and IL-6; reverse transcription polymerase chain reaction (RT-PCR) was used to measure expression of mRNA of claudin 1, occludin, ZO-1, JAM-1, DSG-1 and IL-6.

RESULTS: At day 14 after the procedures, an RE model was established in all subsequently sacrificed rats of groups A, B and C. By both gross and microscopic observation, the mucosa was damaged and thickened as the disease progressed. With TEM observation, a widened intercellular space was noticed, with significantly fewer desmosomes. Immunohistochemistry showed significantly higher levels of all proteins in all RE models compared to control rats at 3 d after operation (65.5% ± 25.6% vs 20.5% ± 2.1%, P < 0.05, respectively). At 14 d after operation, along with continuing hyperplasia in the basal layer, the expression of TJ proteins in individual cells gradually decreased (12.4% ± 2.1% vs 20.5% ± 2.1%, P < 0.05, respectively). Western blottings and RT-PCR showed a directly proportional increase in IL-6 levels in relation to TJ proteins, as compared to controls (0.878 ± 0.024 vs 0.205 ± 0.021 and 0.898 ± 0.022 vs 0.205 ± 0.021, P < 0.05, respectively). Upon treatment with aluminum phosphate, however, these protein levels were restored to normal gradually over 30-60 d in rats with acid RE (30.4% ± 2.1% vs 20.5% ± 2.1%, P > 0.05, treated vs untreated, respectively). These levels increased in the rat with alkaline RE, and this increase was accompanied by continued hyperplasia in comparison with controls (85.5% ± 25.6% vs 20.5% ± 2.1%, P < 0.05, respectively). Furthermore, the expression of TJ proteins was not correlated significantly with that of IL-6 in this group.

CONCLUSION: These findings indicate that TJ proteins are highly expressed as an early molecular event involved in RE development, and that IL-6 is an inflammatory factor in this process.

Cdx genes, inflammation and the pathogenesis of Barrett's metaplasia

Metaplasia is the conversion of one cell or tissue type to another and can predispose patients to neoplasia. Perhaps one of the best-known examples of metaplasia is Barrett's metaplasia (BM), a pathological condition in which the distal oesophageal epithelium switches from stratified squamous to intestinal-type columnar epithelium. BM predisposes to oesophageal adenocarcinoma and is the consequence of long-term acid bile reflux. The incidence of BM and oesophageal adenocarcinoma has risen dramatically in recent years. A key event in the pathogenesis of BM is the induction of oesophageal CDX2 expression. Importantly, recent data reveal the molecular mechanisms that link inflammation in the development of Barrett's metaplasia, CDX2 and the progression to cancer. This review highlights the relationship between inflammation, metaplasia and carcinogenesis.

Protective effects of cholinergic anti-inflammatory pathway against acute esophagitis in rats

AIM: To investigate the effects of cholinergic anti-inflammatory pathway (CAP) on levels of cytokines, choline acetyltransferase (ChAT) and nitric oxide synthetase (NOS) activities and on the degree of acute esophagitis in rats, and to determine whether CAP has protective effects against experimental esophagitis in rats.

METHODS: Acute esophagitis was induced by perfusion of 0.1 mol/L hydrochloric acid with pepsin in the lower part of the esophagus. Forty SD rats were randomly assigned to five groups. Group 1 served as a normal saline-treated control (NS group), while in group 2 the distal esophagus was exposed to acidified pepsin for 2 h (AP group). In the other three groups, animals were subjected to sham surgery (SHAM group) or bilateral cervical vagotomy alone (VTM group) or with electrical stimulation before and after acid perfusion (VNS group). The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10) and activities of ChAT and NOS in the esophageal tissues were determined. Esophageal injury was assessed by macroscopic and microscopic examination.

RESULTS: The levels of TNF-α, IL-6, IL-10 and activities of ChAT and NOS in the esophageal tissues increased after acid perfusion. Compared to the SHAM group, vagus nerve electrical stimulation inhibited the release of TNF-α (135.6 ± 11.6 vs 200.0 ± 20.5, P < 0.05), IL-6 (166.9 ± 44.3 vs 305.6 ± 16.5, P < 0.05) and the degree of esophagitis, while the anti-inflammatory cytokine IL-10 was not affected. Conversely, vagotomy resulted in an elevated severity of esophagitis, associated with significant increase of TNF-α (283.8 ± 33.6 vs 200.0 ± 20.5, P < 0.05) and IL-6 (515.1 ± 77.1 vs 305.6 ± 16.5, P < 0.01) levels and decrease of NOS activity. The esophagitis score was significantly higher in acid treatment group than that in NS group (P < 0.01). The macroscopic and microscopic scores increased in VTM group compared with that in SHAM group (P < 0.01 and 0.05). The esophagitis score was decreased markedly in VNS group compared with that in VTM group (P < 0.01).

CONCLUSION: The results of this study provide evidence for the involvement of the cholinergic anti-inflammatory pathway in modulating inflammation and injury during experimental esophagitis.

Immunomodulatory effects of etanercept in a model of brain injury act through attenuation of the acute-phase response

TNF-alpha has proved to be a successful target in the treatment of many peripheral inflammatory diseases, but the same interventions worsen immune-mediated CNS disease. However, anti-TNF-alpha strategies may offer promise as therapy for non-immune CNS injury. In this study, we have microinjected IL-1beta or lipopolysaccharide (LPS) into the rat brain as a simple model of brain injury and have systemically administered the TNF-alpha antagonist etanercept to discover whether hepatic TNF-alpha, produced as part of the acute-phase response to CNS injury, modulates the inflammatory response in the brain. We report a significant reduction in neutrophil numbers recruited to the IL-1beta- or LPS-challenged brain as a result of TNF-alpha inhibition. We also show an attenuation in the levels of hepatic mRNA including TNF-alpha mRNA and of TNF-alpha-induced genes, such as the chemokines CCL-2, CXCL-5, and CXCL-10, although other chemokines elevated by the injury were not significantly changed. The reduction in hepatic chemokine synthesis results in reduced numbers of circulating neutrophils, and also a reduction in the numbers recruited to the liver as a consequence of brain injury. These findings suggest that TNF-alpha inhibitors may reduce CNS inflammatory responses by targeting the hepatic acute-phase response, and thus therapies for brain injury need not cross the blood-brain barrier to be effective.

Synergistic antitumor effect of combined 5-fluorouracil (5-FU) with 5-chloro-2,4-dihydroxypyridine on 5-FU-resistant gastric cancer cells: possible role of a dihydropyrimidine dehydrogenase-independent mechanism

BACKGROUND

S-1 is an oral fluorouracil antitumor drug that combines three pharmacological agents: tegafur, a prodrug of 5-fluorouracil (5-FU); 5-chloro-2,4-dihydroxypyridine (CDHP), an inhibitor of dihydropyrimidine dehydrogenase (DPD); and potassium oxonate, an agent included to reduce gastrointestinal toxicity. S-1 has a potent antitumor effect on gastric cancer, even in 5-FU-refractory cases. However, there is a lack of basic information to account for this clinical outcome. This study was performed to determine the differences in antitumor effects of combined administration of 5-FU and CDHP between NUGC-3 cells and NUGC-3/5FU/L cells, which are resistant to 5-FU (established by repeated cultures of NUGC-3 with escalating concentrations of 5-FU), and to determine the mechanisms involved.

METHODS

Both cell lines were incubated with various concentrations of 5-FU and/or CDHP. The antitumor effect was assessed using an MTS assay and cell counts. DPD levels were assayed by using enzyme-linked immunosorbent assay. Expression of DPD and thymidylate synthase (TS) mRNA was quantified using real-time quantitative polymerase chain reaction analysis.

RESULTS

The combination of 5-FU (IC15) with CDHP exerted a synergistic antitumor effect on NUGC-3/5FU/L, but not on NUGC-3, while CDHP by itself did not affect cell growth in either cell line. Expression of DPD was not detected in NUGC-3/5FU/L. In NUGC-3/5FU/L, 5-FU-enhanced expression of TS mRNA was inhibited by the addition of CDHP. In contrast, in NUGC-3, administration of 5-FU with or without CDHP did not alter TS mRNA expression.

CONCLUSIONS

The inhibitory mechanism of CDHP, which is independent of DPD, may in part contribute to the antitumor effect of S-1 even in 5-FU-resistant gastric cancer cases.

Proton pump inhibitor-responsive chronic cough without acid reflux: a case report

Background

Because 24-h esophageal pH monitoring is quite invasive, the diagnosis of gastroesophageal reflux disease (GERD)-associated cough has usually been made based merely on the clinical efficacy of treatment with proton pump inhibitor (PPI).

Case presentation

We recently encountered two patients with PPI-responsive chronic non-productive cough for whom switching from bronchodilators and glucocorticosteroids to PPI resulted in improvement of cough. The cough returned nearly to pre-administration level a few weeks after discontinuation of PPI. Though GERD-associated cough was suspected, 24-h esophageal pH monitoring revealed that the cough rarely involved gastric acid reflux. Following re-initiation of PPI, the cough disappeared again.

Conclusion

PPI may improve cough unrelated to gastric acid reflux.

Dickkopf homologs in squamous mucosa of esophagitis patients are overexpressed compared with Barrett's patients and healthy controls

OBJECTIVES

Esophageal mucosal response to acid exposure varies from minimal changes to erosions/ulcerations and Barrett's metaplasia. While differences in acid contact time have been suggested, the reason for these different responses is not completely understood. The aim of this study was to identify and compare gene expression differences between normal distal and proximal squamous esophageal mucosa (SM) in esophagitis patients with that of healthy controls and Barrett's patients.

METHODS

Gene microarray was performed on laser-capture microdissected epithelial cells isolated from biopsy specimens followed by real-time PCR. The effect of acidic pH (pH 4.5) on Dickkopf Homolog 1 (Dkk-1) expression in the human esophageal epithelial cell line (Het-1A) was determined.

RESULTS

Gene microarray analysis demonstrated that the upregulation of five genes in the distal compared with the proximal SM in esophagitis patients was greater than the healthy controls and Barrett's patients. Overexpression of Dkk-1 and Dkk-4 was further confirmed by real-time PCR. Dkk-1 and Dkk-4 mRNA levels in the distal SM of the esophagitis patients were 7.0- and 3.1-fold higher, respectively, than in the distal SM of the Barrett's patients and 4.1- and 4.1-fold higher than in healthy controls, respectively. Dkk-1 protein expression in the distal esophagitis SM was also higher than the Barrett's patients and healthy controls. Acidic pH exposure of Het-1A cells resulted in Dkk-1 upregulation at the level of both mRNA and protein.

CONCLUSIONS

Dkk-1 and Dkk-4 may potentially be involved in the development of different injuries in response to pathological gastroesophageal acid reflux.

Roles of epidermal growth factor and Na+/H+ exchanger-1 in esophageal epithelial defense against acid-induced injury

Epidermal growth factor (EGF) is predominantly secreted by salivary glands and activates Na(+)/H(+) exchanger-1 (NHE-1), which regulates intracellular pH (pH(i)). We investigated the roles of EGF and NHE-1 in esophageal epithelial defense against acid using human esophageal epithelial cell lines and a rat chronic esophagitis model. Esophageal epithelial cells were incubated with acidified medium in the absence or presence of EGF. Cell viability and changes in pH(i) were measured. Chronic acid reflux esophagitis was induced in rats with and without sialoadenectomy. Esophageal lesion index, epithelial proliferation, and expression of EGF receptors and NHE-1 were examined. EGF protected esophageal epithelial cells against acid in a dose-dependent manner, and the cytoprotective effect of EGF was completely blocked by treatment with NHE-1 inhibitors. Tyrosine kinase, calmodulin, and PKC inhibitors significantly inhibited cytoprotection by EGF, whereas MEK, phosphatidylinositol 3-kinase, and PKA inhibitors had no effect. EGF significantly increased pH(i) recovery after NH(4)Cl pulse acidification, and this increase in pH(i) recovery was significantly blocked by inhibitors of calmodulin and PKC. Sialoadenectomy led to an increase in the severity of chronic esophagitis but affected neither epithelial proliferation nor expression of EGF receptors. Expression of NHE-1 mRNA was increased in esophagitis and upregulated in rats with sialoadenectomy. The increasing severity of esophagitis in rats with sialoadenectomy was prevented by exogenous administration of EGF. In conclusion, EGF protects esophageal epithelial cells against acid through NHE activation via Ca(2+)/calmodulin and the PKC pathway. Deficiency in endogenous EGF is associated with increased severity of esophagitis. EGF and NHE-1 play crucial roles in esophageal epithelial defense against acid.

Role of pancreatic trypsin in chronic esophagitis induced by gastroduodenal reflux in rats

BACKGROUND

Reflux of the duodenal contents with gastric acid has been reported to contribute to the development of esophageal mucosal damage and inflammation. Recent studies show that pancreatic trypsin can stimulate the production of inflammatory mediators, including chemokines and prostaglandins from human esophageal epithelial cells in vitro. The aim of the present study was to investigate the role of pancreatic trypsin in the pathogenesis of chronic esophageal inflammation induced by gastroduodenal reflux in rats.

METHODS

Esophagogastroduodenal anastomosis was carried out in male Wistar rats by anastomosing the jejunum to the gastroesophageal junction under diethyl ether inhalation anesthesia. The animals undergoing surgery were treated with the control diet, rabeprazole sodium, nizatidine, ecabet sodium, camostat mesilate (CMM), ONO-1714, a specific inducible nitric oxide synthase (iNOS) inhibitor, or meloxicam, a selective cyclooxygenase-2 (COX-2) inhibitor. Esophageal injury was evaluated by macroscopic and microscopic findings, and mRNA expression for CINC-1, COX-2, and iNOS was determined by real-time polymerase chain reaction (PCR). Trypsin activity within the esophageal lumen was measured 2 weeks after surgery, and the expression of protease-activated receptor (PAR)-1 and -2 was confirmed by reverse transcription (RT)-PCR.

RESULTS

At 8 weeks after surgery, gastroduodenal reflux induced esophageal erosions and ulcer formation as well as marked thickening of the esophageal wall. Histological study showed an increase of thickness of the esophageal mucosa, hyperplasia of the epidermis and basal cells, ulcer formation, and marked infiltration of inflammatory cells. The macroscopic ulcer score and histological ulcer length were significantly reduced by treatment with rabeprazole or CMM but not by nizatidine or ecabet sodium, compared with each control. Rabeprazole, nizatidine, or ecabet sodium did not affect the severity of mucosal hyperplastic scores or histological parameters in esophagitis. In contrast, the CMM group showed a significant decrease in the mucosal hyperplastic and inflammatory scores. The enhanced expression of CINC-1, COX-2, and iNOS mRNA in the control group was also markedly inhibited in the CMM-treated group. ONO-1714 or meloxicam treatment significantly reduced the macroscopic scores of ulcer and hyperplasia. The trypsin activity in the esophageal lumen was significantly increased in the control diet group, and this increase was significantly inhibited in the CMM-treated group. The expression of PAR-1 and -2 mRNA was confirmed in rat esophageal epithelium.

CONCLUSIONS

With this model, we have demonstrated that CMM significantly reduces inflammation and hyperplasia in the esophageal mucosa. These results indicate that trypsin, which is primarily inhibited by CMM, plays an important role in the mucosal damage induced by gastroduodenal reflux and that it can be a therapeutic target in patients with gastroduodenal reflux esophagitis.

Prevention by rebamipide of acute reflux esophagitis in rats

Proinflammatory factors, including neutrophil-derived oxygen free radicals and inflammatory cytokines, have recently been implicated in the pathogenesis of reflux esophagitis. Rebamipide has been widely used as an anti-ulcer agent. The aim of the present study was to assess the protective effect of rebamipide against acute reflux esophagitis in rats. Esophagitis was induced in rats by ligation at the limiting ridge and the lower portion of the duodenum. Vehicle or rebamipide were given as a single dose intraduodenally. Lesion index (LI), thiobarbituric acid-reactive substances (TBA-RS), myeloperoxidase (MPO) activity, mRNA and protein of tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractant (CINC)-1 in the esophageal mucosa were markedly increased; pretreatment with rebamipide, however, significantly reduced both macroscopic and microscopic injuries and increases in inflammatory mediators. The results of this study indicate that rebamipide protects against the occurrence of esophagitis and has highly promising potential as a new therapeutic agent for reflux esophagitis.

Dysphagia associated with gastroesophageal reflux disease is improved by proton pump inhibitor

This study aimed to determine whether dysphagia associated with gastroesophageal reflux disease was effectively treated with rabeprazole, a proton pump inhibitor. Sixty-eight outpatients with gastroesophageal reflux-associated dysphagia were enrolled in this study. Endoscopic esophagitis was confirmed in 52 of 68 subjects. The proton pump inhibitor rabeprazole was administered at 20 mg daily for 8 weeks. Rabeprazole was administered for a further 6 months to 16 subjects whose dysphagia was improved (10 mg/day) and 5 of these underwent 24-hr esophageal pH monitoring before and after treatment. Dysphagia was completely resolved in 40 of 68 subjects, which were categorized in Group I. Dysphagia improved partially in 20 subjects and was unchanged in 8 subjects. These 28 subjects were categorized into Group II. Comparison was made between Group I and Group II and multivariate analysis demonstrated that the only factor that correlated with the effect of rabeprazole on dysphagia was "improvement in heartburn symptoms." There were no relapses of symptoms during the 6-month follow-up period, and pH monitoring showed sustained suppression of acid secretion. The results indicate that rabeprazole is effective in the treatment of dysphagia associated with gastroesophageal reflux disease. We were, however, unable to elicit any factors that could predict the therapeutic effect of rabeprazole before commencing treatment.

Functional oesophageal epithelial defense against acid

Functional oesophageal epithelial defense, including cell proliferation, restitution, buffers and ion transporters, plays a significant role in maintaining mucosal integrity and enabling rapid repair after injury. Growth factors such as epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) are associated with oesophageal epithelial proliferation or restitution. Na+/H+ exchanger-1, an ion transporter, regulates intracellular pH and cell volume, and may have roles in cell proliferation, migration and survival. Cytokine, adhesion molecules, cyclooxygenase-2 and free radicals are associated with oesophageal inflammation and breach of the functional epithelial defense. Although the oesophagus does not have strong functional epithelial defense against acid, this defensive mechanisms may be involved in the pathogenesis of non-erosive gastro-oesophageal reflux disease. Medical therapy may be developed in future to enhance functional oesophageal epithelial defense.

Altered localization and expression of tight-junction proteins in a rat model with chronic acid reflux esophagitis

BACKGROUND

The esophageal tight junction is responsible for the paracellular sealing of the epithelium. Alteration of the expression of tight-junction proteins plays crucial roles in the pathogenesis of some human diseases. The aim of this study was to investigate the distribution and expression pattern of tight-junction proteins in the esophageal mucosa of control rats and rats with reflux esophagitis.

METHODS

Chronic acid reflux esophagitis was experimentally induced by operation in rats. The animals were killed on days 7 and 14 after the operation. The thickness of the mucosa and the 5-bromo-2-deoxyuridine (BrdU) labeling index were assessed. The expression pattern of the tight-junction proteins claudin 1-4 and occludin in the esophageal mucosa was investigated by immunofluorescence staining and Western blotting in the controls and esophagitis rats.

RESULTS

In the esophagitis model, the thickness and BrdU labeling index increased with time. In control rats, claudin-1, -3, and -4 were localized on the cellular membranes of esophageal epithelial cells, mainly in the spinous and granular layers, while claudin-2 was not detected in any layer. Occludin was seen on the cellular membranes in all esophageal mucosal layers. In the esophagitis rats, the expression of claudin-1 was increased both in the plasma membrane and in the cytoplasm around the erosion in the spinous and granular layers. The expression of claudin-4 and occludin shifted to the cytoplasm from the plasma membrane in the spinous and granular layers. In contrast, the expression of claudin-3 was decreased in the spinous and granular layers.

CONCLUSIONS

The localization and the expression patterns of tight-junction proteins were different in the controls and the rat esophagitis model. The expression of claudin-3 in the esophageal mucosa was decreased, while that of claudin-1 was increased. It is postulated that these alterations in tight-junction proteins most likely increase the permeability of the esophageal the epithelium, thereby impairing the defense mechanism of this epithelium.

CDX1 is an important molecular mediator of Barrett's metaplasia

The molecular pathogenesis of Barrett's metaplasia (BM) of the esophagus is poorly understood. The change to an intestinal phenotype occurs on a background of esophagitis due to refluxing acid and bile. CDX1, an important regulator of normal intestinal development, was studied as a potential key molecule in the pathogenesis of BM. CDX1 mRNA and protein were universally expressed in all samples of BM tested but not in normal esophageal squamous or gastric body epithelia. This tissue-specific expression was attributable to the methylation status of the CDX1 promoter. Conjugated bile salts and the inflammatory cytokines TNF-alpha and IL-1beta were all found to increase CDX1 mRNA expression in vitro. These effects were primarily mediated by NF-kappaB signaling but only occurred when the CDX1 promoter was unmethylated or partially methylated. The data suggest that CDX1 is a key molecule linking etiological agents of BM to the development of an intestinal phenotype. Although the initial trigger for CDX1 promoter demethylation is not yet identified, it seems likely that demethylation of its promoter may be the key to the induction and maintenance of CDX1 expression and so of the BM phenotype.

Interleukin-8 expression in the esophageal mucosa of patients with gastroesophageal reflux disease

BACKGROUND

It has been reported that inflammatory cell infiltration can be detected in patients with endoscopically negative gastroesophageal reflux disease (GERD) as well as those with erosive reflux esophagitis. In this study, we examined the expression of mRNA for interleukin (IL)-8, a potent chemokine for neutrophils, in the esophageal mucosa of patients with GERD and compared the results with their endoscopic findings and symptoms.

METHODS

Biopsy samples were obtained from 80 patients. Endoscopic diagnosis was performed according to the Los Angeles classification. Patients with typical symptoms such as heartburn despite normal endoscopic findings were classified as the non-erosive GERD group. Total cellular RNA was extracted from the biopsy samples and IL-8 mRNA was quantified by real-time polymerase chain reaction (PCR). Localization of IL-8 protein in the esophageal mucosa was done by immunostaining.

RESULTS

Expression of IL-8 mRNA was correlated with the endoscopic grade of esophagitis or with inflammatory cell infiltration, but not with the symptoms of the patients. Expression of IL-8 mRNA was also detected in all patients with non-erosive GERD. The level of IL-8 expression in non-erosive GERD was low compared with that in erosive GERD, but was higher than that in normal controls. IL-8 immunostaining was found in the basal layers of the esophageal mucosa. Administration of lansoprazole, a proton-pump inhibitor, decreased both IL-8 mRNA and protein levels in the esophageal mucosa.

CONCLUSION

These results suggest that IL-8 in the esophageal mucosa may be involved in the pathogenesis of esophageal inflammation, including non-erosive GERD.