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spreinduction of HSPs on cytokine levels (TNF-α and IL-1β in the esophagus, esophagealmucosa was also analyzed using enzyme-linked immunosorbent assay (ELISA). Results:Expression of HSP72 was significantly increased by hyperthermia in rat esophageal mucosawhereas expression of HSP60 andHSP90 did not increase. Reflux esophagitis was dramaticallyprevented when HSP72 was preinduced by hyperthermia. Furthermore, activation of TNF-α and IL-1β in esophageal mucosa was also suppressed. Conclusions: These results suggestedthat hyperthermia protects the esophageal mucosa in reflux esophagitis model by inducingHSP72 and suppressing proinflammatory cytokine activation. These findings might suggestthat HSP-inducing therapy could be a novel and unique therapy for reflux esophagitis. Thisis the first report analyzing the function of molecular chaperone as an internal mucosalcytoprotectant in the esophageal mucosa.

M1815

A Microscopic Esophagitis Is the Basic Underlying Condition in Non-ErosiveReflux Disease (NERD)Klaus Mönkemüller, Thomas Wex, Helmut Neumann, Doerthe Kuester, Lucia C. Fry,Albert Roessner, Peter Malfertheiner

Introduction: NERD is often accompanied by microscopic changes in the distal esophagealmucosa. Aim: To investigate microscopic and molecular-biologic abnormalities in NERDusing magnification endoscopy (ME), histology, electron microscopy (EM), molecular andimmunohistochemical studies (IHC) of the intercellular spaces (ICS) and tight junctions(TJ) of the distal esophagus. Patients and Methods: 40 patients with typical GERD symptomsand responsiveness to PPI-therapy and 10 asymptomatic controls were included. The GERD-group comprised 25 and 15 patients with NERD and erosive reflux disease (ERD, LosAngeles grade A and B), respectively. A magnification endoscope (Q160 Z, x115, Olympus)was used to investigate the esophagus and cardia. Two endoscopists analyzed the photos.Interobserver variability was calculated using k-statistics. Multiple biopsies were taken forhistology (H&E, PAS), EM (x3000 and x7000) and molecular analyses. Measurement of theintercellular space volume with EM was performed with the method of Weibel. Geneexpression patterns of junctional proteins were analyzed by quantitative RT-PCR, proteinexpression by semiquantitative IHC. Statistics: non-parametric Mann-Whitney U test. Results:Endoscopic changes on magnification endoscopy (villous cardia, red streaks, intrapapillarycapillary loops or IPCL) were more common in NERD (45.7-62.8%) as compared to controls(8-28%) (p=0.04-0.004), kappa values: 0.56-.88). On histology patients with both NERDand ERD had a higher incidence of hypertrophy of the papillae (66% and 84%), basal cellhyperplasia (80% and 88%) and inflammatory infiltrates (73% and 80%) (p=0.008-0.0001).EM demonstrated that the volume of the ICS volume was increased in GERD (ERD: 24%,NERD 20%) as compared to controls (16%) (p=0.005-0.038)). The transcript levels ofoccludin were upregulated 1.8 fold in the esophageal mucosa of both NERD and ERD incomparison to controls (p=0.007-0,25). In NERD and ERD, claudin-1 expression was 2-and 3.1-fold upregulated in esophageal mucosa (P<0.02). IHC confirmed data from RT-PCR. Claudin-1 was detectable on IHC with staining scores of 1, 2 and 6 (p<0.001) incontrols, NERD and ERD, respectively. Conclusions: For the first time we have demonstratedthat there is a correlation of magnification-endoscopic, histologic, electronmicroscopic andmolecular changes of the distal esophageal mucosa of patients with ERD and NERD andthat these changes occur more commonly than in controls. The dilation of the ICS (i.e.increased volume) observed on electron-microscopy is associated with an increased expres-sion of the TJ proteins suggesting a role of the TJ in the pathogenesis of GERD.

M1816

Alterations in Esophageal Acid Sensitivity in Older Adults with GERDChien-Lin Chen, Chih-Hsun Yi, Tso-Tsai Liu, William C. Orr

Background: Aging is associatedwith decreased sensory perception and altered biomechanicalfeatures in the esophagus. The effect of age on esophageal response to experiment acidificationin gastroesophageal reflux disease (GERD) has not been fully explored. This study aimedto compare the effect of intraluminal acidification on esophageal sensory perception andmotor activity in older (aged 60 or older) and younger patients with GERD. Methods: Aprospective study of 40 patients referred for investigation of reflux symptoms was conducted.Esophageal acid exposure and mucosal injury were evaluated by ambulatory pH monitoringand upper endoscopy. All subjects had saline and hydrochloric acid infused into the mid-esophagus. Esophageal body motility was recorded at baseline and during each infusionperiod. The esophageal response to acid infusion was documented including lag time,intensity rating, and sensitivity score. Results: Twenty patients were studied in each group.Acid infusion induced typical heartburn in 100% of the younger patients compared to 55%of the older patients (p = 0.001). The younger group had a significantly shorter lag time toinitial heartburn perception (p = 0.01) and a greater sensory intensity rating (p = 0.001).The acid infusion sensitivity score was significantly lower in the older patients (p = 0.001).Age positively correlated to lag time to initial symptom perception (R = 0.44, p = 0.005),but negatively correlated to sensory intensity (R = −0.40, p = 0.01) and acid infusionsensitivity score (R = −0.39, p = 0.01) in all individuals. The amplitude of peristaltic wavesin distal esophagus was greater during saline (p < 0.05) and acid infusion (p < 0.05)compared to baseline only in younger patients. When compared with saline infusion, acidinfusion induced a significant increase in the deglutition frequency in younger patients (0.51vs 0.67, p = 0.005), but not in older patients (0.59 vs 0.65, p = 0.67). Conclusions: Agingwas associated with the reduction in sensory perception and motor responses to esophagealacidification. Conclusion: Age-related alterations in sensorimotor response to esophagealacidification may be an important element in the pathogenesis and clinical presentation ofGERD in older adults.

A-424AGA Abstracts

M1817

Intresophageal Perfusion of Hcl (0.1n) Stimulates Expression of CanonicalWnt Ligand Wnt-3a in the Esophageal Mucosa of Healthy VolunteersIrshad Ali, Jonathan Huang, Sri Naveen Surapaneni, Linda Tatro, Parvaneh Rafiee, RezaShaker

Earlier studies of full thickness esophagus have shown differential distribution of Wntsignaling components across the esophageal squamous mucosa with the canonical Wntligands Wnt-1, Wnt-2b and Wnt-3 andWnt-3a preferentially localized, at or in juxtapositionto the basal cell layer. Subsequent studies have shown that expression of the canonicalligand Wnt-1 was significantly increased in esophageal epithelial Het-1A cells exposed tolow pH suggesting that this ligand may be involved in the homeostasis of the esophagealmucosa. However, since Het-1A cells are immortalized, the current study was undertakento determine whether the low pH response observed in these cells was relevant to theesophageal epithelial cell response to low pH In Vivo. AIM: To determine the effect of lowpH on the expression of canonical Wnt ligands in the human esophageal squamous mucosaIn Vivo. METHODS: Eight healthy human volunteers (aged 21-66 y) were used for thisstudy. Transnasal unsedated endoscopy was performed to confirm normalcy of the esophagusand to obtain biopsy specimens before and one and 4h after 0.1N HCl perfusion (2ml/min).Biopsies were taken from the same horizontal region 5cm above the LES. Biopsy sampleswere flash frozen and processed for Western blot analysis. Band densities were determinedwith NIH Image J software and the results expressed as a ratio of gene protein product/B-actin. RESULTS: Wnt-3a protein expression was significantly greater in biopsies taken at4h post acid perfusion compared to biopsies taken from pre-acid infused mucosa (A,*p<0.05). Wnt-1 protein levels nearly doubled at 4h but did not reach statistical significance.c-Myc protein, a target gene of the Wnt pathway was significantly increased at 1h (B,*p<0.025) and 4h after acid perfusion (B, **p<0.001) compared to levels in biopsies frompre-acidified mucosa. Conclusions: 1) Acid exposure increasesWnt-3a in esophageal mucosa.2) Stimulation of Wnt-3a, a canonical Wnt ligand involved in cell proliferation by low pHsuggests that it may be involved in basal cell hyperplasia observed in GERD patients.

M1818

Oxidative Stress Modulates TRPV1 Activity On Esophageal EpitheliumEtsuko Kishimoto, Osamu Handa, Yuji Naito, Ikuhiro Hirata, Tatsushi Omatsu, TomohisaTakagi, Satoshi Kokura, Hiroshi Ichikawa, Norimasa Yoshida, Toshikazu Yoshikawa

Introduction: Human esophageal epithelium is always exposed to physical stimuli or acidthat sometimes cause inflammation of mucosa. Transient receptor potential vanilloid 1(TRPV1) is a sensory neuron-specific ion channel activated by capsaicin, heat and protons.Reacently it has been reported that TRPV1 is expressed in esophageal mucosa and theiractivation is involved in GERD or NERD symptoms. Furthermore, the redox state has beenshown to modulate TRPV1 receptor activity. So we focused on the involvement in oxidativestress-induced post-translational modification of TRPV1 in the analysis of its activation bycapsaicin using esophageal epithelial cells (HET-1A) In Vitro.Methods: TRPV1 protein ofHET-1A was determined by Western blot analysis and immunoreactivity. Interleukin-8 (IL-8) in the supernatant was measured by ELISA after the stimulation by capsaicin with/without4-hydroxy-2-nonenal (HNE) preincubation. Intracellular production of reactive oxygen spe-cies (ROS) was determined by redox-sensitive fluorescent probe, RedoxSensor. ROS- andHNE-modified proteins were determined byWesten blot analysis using biotin-labelled cysteinand anti-HNE monoclonal antibody, respectively. Result: TRPV1 was expressed on themembrane of HET-1A. TRPV1 protein was recognized on 100KD by Western blot. Capsaicininduced IL-8 prodution from HET-1A in a dose dependent manner, and its production wasdiminished with antagonists of TRPV1, capsazepine and ruthenium red. Intracellual ROSlevels and ROS- and HNE-modified proteins were increased after the stimulation withcapsaicin. Moreover, preincubation with synthetic HNE enhanced IL-8 production in HET-1A cells stimulated with capsaicin. Conclusion: TRPV1 is expressed in not only sensoy nerveof esophageal mucosa but also esophageal epithelium. TRPV1 on esophageal epitheliumcells has the funtion of chemokine producion, and that funcion might be regulated by ROSvia the post -translational modification of TRPV1.

M1819

Exposure to Acid and Bile Salts Causes Esophageal Squamous Cells to SecreteChemokines That Stimulate Immune Cell MigrationXiaofang Huo, Hui Ying Zhang, Xi Zhang, Kathy Hormi-Carver, Stuart J. Spechler,Rhonda F. Souza

Introduction: In rats that had esophagoduodenostomy, we found that reflux esophagitisdeveloped in a fashion more consistent with an immune-mediated injury than with achemical burn (acid-peptic) injury. We hypothesized that refluxed material might inducethe esophageal squamous epithelial cells to secrete chemokines that attract inflammatorycells, which subsequently damage the epithelium. To explore this hypothesis, we exposedesophageal squamous epithelial cells to acid and bile salts, and studied effects on chemokinesecretion and immune cell migration. Methods: Two non-neoplastic, telomerase-immortal-ized esophageal squamous cell lines derived from patients with GERD were exposed toacidic media (pH 4) containing conjugated bile acids (total concentration 400 μM), or toneutral media (pH 7) without bile acids for 10 minutes TID for 5 days. We used ELISA tomeasure the concentration of IL-8, a chemokine involved in neutrophil and lymphocytemigration, secreted into the conditioned media (CM) after each day of exposure. To studyeffects on immune cell migration, we used a transwell system in which immune cells loadedinto one chamber were observed to migrate into another in response to 3 test solutions(CM alone, IL-8 alone, and CM with an IL-8 blocking antibody). Immune cells included ahuman T-cell line (Jurkat), a mouse macrophage cell line (Raw264.7), a human neutrophilline (HL-60 promyelocytic leukemia cells differentiated with DMSO), and a humanmonocyteline (HL-60 cells differentiated with PMA). Results: We observed a significant increase inIL-8 secretion by both esophageal cell lines after 2 days of exposure to acidic bile salt media;IL-8 secretion continued to increase through day 5. CM collected at days 4 and 5 caused