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Su1952 TH17 Pathway Promotes Mucosal Host Defense Against Esophageal Candidiasis in HIV-Infected Patients
Parietal cells are particularly affected. Whether or not parietal cell dysfunction leads to poor organization of the gastric glands is unknown, and will be the subject of future study.
Su1950 Effect of Celecoxib, a Selective Cycloxygenase-2 Inhibitor, on Acid-Induced HCO3- and Ulcerogenic Responses in Rat Duodenums; A Comparative Study With Conventional Non-Steroidal Anti-Inflammatory Drugs Koji Takeuchi, Kikuko Amagase, Hiroshi Satoh
AGA Abstracts
Su1948 In Vivo, Real Time Non-Invasive Assessment of Gastric Mucosal Injury Using Confocal Laser Endomicroscopy: Focus on Mucosal Microvessels, Progenitor Cells and Mucosal Protection. Direct Comparison With Quantitative Histology and Electron Microscopy. Andrzej S. Tarnawski, Amrita Ahluwalia, Michael K. Jones, Ercheng Zhu
Duodenal HCO3- secretion increases in response to luminal acid. This response is mainly mediated by endogenous prostaglandin E2 (PGE2) derived from cyclooxygenase (COX)-1. However, a recent study showed in cats that rofecoxib, a selective COX-2 inhibitor, by itself damaged the duodenal mucosa, similar to indomethacin, a non- selective COX inhibitor. In the present study, to confirm the importance of COX-1 in the duodenal mucosal defense, we examined the effect of celecoxib, another COX-2 selective inhibitor, on HCO3- and ulcerogenic responses caused by acid in rat duodenums. Methods: Male SD rats were used after 18 h fasting. Under urethane anesthesia, a loop made in the proximal duodenum was perfused with saline, and the HCO3- secretion was measured at pH 7.0 using a pH-stat method and by adding 10 mM HCl. Mucosal acidification was performed by exposing the loop to 10 mM HCl for 10 min. In addition, the duodenal damage was induced by perusing the loop with 100 mM HCl at a flow rate of 1 ml/h for 4 h. Indomethacin (5 mg/kg), loxoprofen (10 mg/kg), SC-560 (a selective COX-1 inhibitor, 3-30 mg/kg) and celecoxib (a selective COX-2 inhibitor, 30 mg/kg) were given ID 1 h before exposure to 10 mM HCl or the onset of 100 mM HCl perfusion. Results: The mucosal acidification stimulated HCO3secretion with an increase of mucosal PGE2 contents in the duodenum. The increase of HCO3- secretion and PGE2 content in response to acidification were significantly inhibited by prior administration of indomethacin. Likewise, a selective COX-1 inhibitor SC-560, dose-dependently inhibited the HCO3- response to acidification; a significant effect was observed at 10 mg/kg, together with the effect on the increased PGE2 production. However, a selective COX-2 inhibitor celecoxib had no effect on either of these responses. RT-PCR analyses showed that COX-2 mRNA was not expressed in the duodenal mucosa after acidification, while COX-1 mRNA was expressed in the normal mucosa and remained unchanged before and after acid treatment. On the other hand, perfusion of the loop with 100 mM HCl for 4 h produced mild hemorrhagic damage, and the severity of these lesions was significantly worsened by indomethacin, loxoprofen and SC-560, while celecoxib did not affect. Conclusion: These results confirmed that COX-1 is a key enzyme responsible for producing PGs involved in the mechanism for the acid-induced HCO3- secretion in the duodenum, and further suggested that COX-1/PGs play a crucial role in the protection of the duodenal mucosa against acid injury.
Background/Aims: Studies of gastric mucosal injury and healing rely on macroscopic and histological assessment of fixed stomach specimens, which may not fully reflect in vivo events. As a result, the cellular targets and real time sequence of gastric mucosal injury are not fully defined. Confocal laser endomicroscopy (CLE), a novel cutting edge technology, has enabled in vivo real-time visualization of mucosal structures at a subcellular resolution. This study was aimed to: 1) assess acute gastric injury in real time using CLE with a focus on mucosal microvessels and progenitor cells; 2) determine whether hydrotalcite (HTL), the newest generation antacid, can protect gastric mucosa against ethanol injury; and, 3) identify the mechanisms involved. Methods: Fischer F344 rats received 1 ml 0.5% fluorescein i.v. followed by intragastric (i.g.) ethanol (1 ml, 50%) or saline. In some rats, either 1 ml of vehicle or HTL (20mg/kg) was given i.g. 30 min prior to ethanol. CLE was performed using the CellvizioLAB LSU F400 with Z ProFlex probe inserted i.g. and CLE images were monitored for 30 min before and after ethanol administration. Studies: 1) CLE imaging of gastric mucosa including epithelium and microvasculature; 2) vascular permeability; 3) mucosal blood flow dynamics; 4) progenitor cell integrity; 5) molecular imaging of VEGFR2 using labeled antibody; 6) detection of i.v. injected bone marrow-derived stem cells (BMDSC) in gastric mucosa. For comparison we performed quantitative histology, and transmission and scanning electron microscopy (EM). Results: At baseline, CLE of rat gastric mucosa demonstrated a normal gastric gland pattern, vasculature, continuous microvascular blood flow and low vascular permeability. Ethanol induced the exfoliation of surface epithelium within 2-3 min, followed by a 550% increase in vascular permeability (p<0.001) at 3-5 min; rupture of microvessels within 5-10 min, extensive extravasation of erythrocytes and vascular stasis. Progenitor cells were severely damaged. Histology and EM confirmed these changes. Pretreatment with HTL reduced ethanol-induced vascular permeability by 55% (p<0.01), preserved blood flow and reduced extent and severity of injury (all p<0.01). In control rats VEGFR2 was visualized in endothelial cells of blood vessels and i.v. injected BMDSC were present in gastric microcirculation. Conclusions: 1) CLE enables precise in vivo, real time analysis of events taking place during gastric mucosal injury and evaluation of mucosal protection. 2) Microvascular injury and increased vascular permeability occur early and precede progenitor cell damage and deep hemorrhagic necrosis. 3) CLE provides a significant advantage over standard histologic and EM assessment, by allowing real time monitoring of in vivo mucosal structure and function, e.g. vascular permeability, and in vivo molecular imaging.
Su1951 Recovery of Gastric Function After Acetium Administration: A 6 Months Study in Atrophic Gastritis Subjects Francesco Di Mario, Hunor Pal Farkas, Francesco Ferrara, Nadia Dal Bo, Tiziana Slongo, Roberto Marcello, Massimo Rugge, Carmelo Scarpignato Background: No consensus from different studies exists regarding the reversibility of atrophic gastritis; however, removal of H pylori from the already atrophic stomach may block further progression of the disease. Although studies report a partial restoration of serum pepsinogen I (sPGI) levels after eradication, it is not clear if this finding reflects gastric mucosal healing on a morphological level. Immune-mediated atrophic changes in the stomach by definition seem to be irreversible. Recently a new compound (L-cystein Acetium, Biohit, Finland) has been proposed for prevention of gastric carcinogenesis in patients with atrophic gastritis, by reducing acetaldehyde (class I human carcinogen) production after food intake. Aims: To assess the changes in gastric function after long term administration of L-cysteine in moderate to severe atrophic gastritis by sPGI and gastrin 17 (sG17). Methods: 30 patients with histological features of moderate-severe body atrophic gastritis and sPGI < 25 μg/L (7 men, mean age 47.9 years, range 27-71) had sPGI and sG17 measured at baseline. In 8 patients autoimmune origin was confirmed by anti-parietal cell antibodies, the rest underwent eradication therapy for Helicobacter pylori infection earlier. Long term oral therapy with Acetium (3x100mg L-cysteine/day before meals) has been initiated and serologic markers were determined at 3 and/or 6 months. Results Mean sPGI levels prior to treatment were 7.9 μg/L, compared to the latest measurements' mean of 11,38 μg/L (p<0.001) reflecting possible increase in active parietal cell mass. On the other hand the mean baseline level of sG17 decreased from 34.4 pmol/L to 26,25 pmol/L (p<0.001) indicating changes in the negative feedback of the regulation transmitted by gastrin. In a few cases, where multiple serological measurements were available, an obvious increasing trend was observed in sPGI levels over time, as well as decrease in sG17 levels. Conclusion: L-cysteine seems to be useful in restoring gastric secretion in subjects with chronic atrophic gastritis both after H.p. eradication and in case of autoimmune etiology.
Su1949 Esophageal Mucosal Integrity Recovers After Laparoscopic Fundoplication in Children With Gastroesophageal Reflux Disease Femke A. Mauritz, Nicolaas Fedde Rinsma, José M. Conchillo, Ernst van Heurn, Peter D. Siersema, David C. van der Zee, Maud van Herwaarden-Lindeboom Background Esophageal intraluminal baseline impedance levels reflect the electrical resistance of the esophageal wall and may serve as an instrument for in vivo evaluation of esophageal mucosal integrity in gastroesophageal reflux disease (GERD) in children. Fundoplication as treatment for GERD aims to reduce (acid) reflux events and restore mucosal integrity. This could be reflected by increased intraluminal baseline impedance levels after operation. The aim of this study was, therefore, to evaluate the effect of laparoscopic fundoplication on mucosal integrity by assessing intraluminal baseline impedance levels before and after fundoplication in children with GERD. Methods Eleven children (5 males) with therapy resistant GERD were included. Median age was 6.5 years (range, 1.6 - 18.2) at the time of laparoscopic fundoplication. Twenty-four hour multichannel intraluminal impedance pH monitoring (MII-pH monitoring) was performed before and 3 months after fundoplication. For every consecutive two hour intervals in the 24-h tracings, intraluminal baseline impedance levels were measured over a period of ≥ 30 seconds not containing any swallows or gastroesophageal reflux episodes. Intraluminal baseline impedance levels were calculated over four segments (3, 5, 7 and 15 cm above the LES) using a specific function incorporated in the analysis software (Ohmega MMS). Results Fundoplication was successful in reducing total acid exposure time (from 11.4% ± 2.3% to 0.9% ± 0.3%, p<0.001) and overall number of reflux episodes (from 106.5 ± 20.1 to 19.7 ± 3.9, p=0.001). The mean distal baseline impedance level increased after fundoplication (from 2423 ± 414 Ω to 3560 ± 328 Ω, p<0.01). Baseline impedance levels also increased at 5 cm (from 2969 ± 428 Ω to 4105 ± 300 Ω, p=0.02) and 7 cm segments (from 3124 ± 459 Ω to 3980 ± 248 Ω, p=0.04) above the LES. In the proximal segment, no significant changes were found after fundoplication (from 3099 ± 341 Ω to 3621 ± 172 Ω, p=0.12). Prior to fundoplication, mean distal baseline impedance level showed a negative correlation with acid exposure time (r: -0.78, p<0.01). We also observed a gradual increase of intraluminal baseline impedance levels from the distal to the proximal impedance segment in the esophagus, reflecting the distribution of acid exposure in the esophagus. Conclusion Reduction of acid exposure and number of reflux episodes by laparoscopic fundoplication leads to a significant increase in intraluminal baseline impedance levels in children with GERD, which may indicate repair of mucosal integrity and success of therapy.
AGA Abstracts
Su1952 TH17 Pathway Promotes Mucosal Host Defense Against Esophageal Candidiasis in HIV-Infected Patients Ana Luiza Werneck-Silva, Carla Pagliari, Rosely A. Patzina, Wellington F. da Silva, Luciane K. Galo, Maria Irma S. Duarte INTRODUCTION: Esophageal candidiasis is the most common opportunistic infection in the GI tract in HIV+ patients. Host defense mechanisms against Candida albicans vary by anatomical site, as HIV+ patients are primarily susceptible to oropharyngeal and esophageal, but not vaginal or disseminated candidiasis. Although immunity to C. albicans was long considered to be mediated by Th1 cells, new data in both rodent and in humans have revealed a role for the Th17 lineage, a subset of effector T cells that are localized at the mucosal level, including the gut mucosa. To date, the relative contribution(s) of Th1 and Th17 responses in esophageal candidiasis have not been defined. AIMS: To determine the role of mucosal T cell immunity and IL-17 pathway against esophageal Candida infection in HIV+ patients. METHODS: Immunohistochemistry to CD4+ and CD8+ T cells, INFγ, TGFβ, IL-6 and IL-17 were performed in esophageal histological samples obtained from endoscopy in 28 HIV+, 16 with Candida esophagitis (Group A) (6 female and 10 male)
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min, 24 and 72 hours (H24, H72) after direct application of CKT and placebo tablets (PLT). Characterizations included endoscopic, probe-based confocal laser endomicroscopy, histological examinations and ex vivo permeability measurements on mucosal resection. Results: At 90 min, enanthema was observed in 57% of animals at CKT sites. At H24 two pigs showed enanthema and one pig an aphtous lesion at the CKT site. At PLT sites, the aspect was normal at 90 min but enanthema was observed in 22% of animals at H24. At H72, no lesion was identifiable in any animal for any site. At 90 min, CKT sites showed a significant increase in epithelial irregularity and crypt pit intensity, which remained unchanged at H24. PLT induced a slight but significant increase in epithelial irregularity and architectural disorganization. At H72, semi quantitative scores and crypt pit intensity were significantly reduced and similar to H0. At PLT sites, crypt pit and intercryptic intensities remained unchanged. Mucosal thickness at CKT sites was similar to that at CTRL sites. Fundic paracellular permeability was not changed at CKT sites. Conclusions: Direct and prolonged gastric application of Colokit® tablets in pigs induces acute superficial macroscopic and microscopic injuries in some animals. These lesions are spontaneously reversible in less than 72 hours. Su1955 Inactivation of Carcinogenic Acetaldehyde by Slowly L-Cysteine Releasing Capsule Formulation in Gastric Juice of PPI Treated Volunteers After IntraGastric Infusion of Ethanol Ryuhei Maejima, Katsunori Iijima, Panu H. Hendolin, Pertti Kaihovaara, Lea I. Paloheimo, Tomoyuki Koike, Tooru Shimosegawa, Kari J. Syrjänen, Mikko Salaspuro INTRODUCTION: Acetaldehyde (ACH) associated with alcoholic beverages has been classified as carcinogenic (Group 1) to humans by IARC/WHO. Gastric mucosa, many microbes colonizing acid-free or hypochlorhydric stomach as well as many Helicobacter pylori strains possess alcohol dehydrogenase activity capable of locally producing ACH from ethanol. ACH produced from ethanol in oral cavity and esophagus contributes to local ACH exposure in the upper digestive tract. Atrophic gastritis and H. pylori infection associated with enhanced exposure to locally formed ACH are the two most important risk factors for gastric cancer. Furthermore, ethanol-derived ACH may contribute through gastro-esophageal reflux to the pathogenesis of esophageal squamous cell carcinoma. Aldehyde dehydrogenase (ALDH2), a major enzyme responsible for ACH elimination, is genetically deficient among 30-50% of Eastern Asians. In alcohol drinkers, ALDH2-deficiency associates strongly with increased risk for upper digestive tract cancers through exposure to ethanol-derived carcinogenic ACH via saliva. Capsule that slowly releases L-cysteine in the stomach converting ACH to inactive 4-methyltiazolidine-2-carboxylic acid (MTCA) has been recently implicated in prevention of gastric carcinogenesis among patients with atrophic gastritis. AIMS: To assess the effect of PPI-treatment on gastric juice ACH levels, following an intra-gastric infusion of 15% ethanol, with or without administration of L-cysteine. The final results will be stratified according to the individual ALDH2 genotypes. METHODS: The final study cohort comprises ten ALDH2-active and ten ALDH2-deficient H. pylori negative healthy volunteers. Through a nasogastric tube 15% ethanol (0.5g/kg) is infused into the stomach. 5ml of gastric aspirates and saliva are collected at 30-min intervals up to 120 min. The first aspirations are done before and after 7-day administration of proton pump inhibitor (PPI, rabeprazole 10mg b.i.d.) (experiment 1 and 2). After 3 more days on PPI, aspiration is repeated with 200mg of slowly releasing L-cysteine administered before ethanol infusion (experiment 3). RESULTS: Thus far, 11 volunteers have completed the three experiments. PPI treatment increased gastric juice ACH levels by an average of 50% for 2 hours (p=0.0428 at 30min.). After intake of L-cysteine free ACH levels in gastric juice decreased by a mean of 60% up to 120min (p=0.005, p=0.003, p=0.03 at 30-,60- and 90min, respectively). The possible effect of ALDH2 polymorphism on gastric juice ACH levels will be elucidated when all 20 subjects have completed the study protocol. CONCLUSIONS: The results confirm the previous reports on PPI treatment as a trigger of free ACH levels in gastric juice. An average of 60% of the ethanol-derived carcinogenic ACH in the stomach can be inactivated by concomitant administration of slowly releasing L-cysteine.
Group A= HIV+ patients with esophageal Candidiasis Group B= HIV+ patients without Candidiasis Group C= HIV negative healthy controls without Candidasis Su1953 Esophageal Strictures in Children Contain Focal Obliterative Muscularization and Mural Inflammation Margaret H. Collins, Eileen S. Alexander, Lisa J. Martin, Tommie M. Grotjan, Juan P. Abonia, Vincent A. Mukkada, Philip E. Putnam, Marc E. Rothenberg Background: Esophageal strictures (ES) in children cause significant morbidity, but are not well characterized pathologically. We report unique histopathologic analyses of surgically resected pediatric ES and control esophagi (CE--obtained at autopsy). Methods: Slides of ES (n=10) and CE (n=8) identified in our pathology database (1/1968-4/2013) were reviewed; additional slides from paraffin blocks containing transmural sections were stained with actin (1A4, 1:1,000, Cell Marque, Rocklin, CA), tryptase (predilute, Ventana, Tucson, AZ), or chymase (1:50, Abd Serotech, Raleigh, NC) antibodies. Muscularis mucosa and propria thicknesses were measured in millimeters in architecturally-intact well-oriented areas using an eyepiece reticle. Peak mast cell (PMC) and eosinophil counts were obtained from the most inflamed high power field (hpf) viewed at 400X (0.3 mm2). Results were expressed as median, lower and upper quartiles. Wilcoxon Rank Sums non-parametric t-test was used to compare groups and P≤0.05 was considered significant. Results: Age at sample collection did not differ between CE and ES patients (2.5 (0.5-4.9) vs 3.7 (2.5-10.5) years, P=0.2). Causes of ES were caustic ingestion (5/10—mean time from ingestion to resection was 10 months), reflux (2/10), congenital abnormality and possible eosinophilic esophagitis (1/10), and unknown (2/10). All ES showed significant structural alterations compared to CE. Specifically, lamina propria, muscularis mucosa, and submucosa were replaced by fibromuscular foci (obliterative muscularization) containing actin+ fibers which were continuous with muscularis propria. In areas of preserved architecture, compared to CE ES displayed significantly thickened muscle layers: muscularis mucosa (1.2 (0.65-1.49) vs 0.19 (0.100.33) mm, P=0.002) and propria (3.1 (2.68-4.4) vs 1.2 (0.92 - 1.68) mm, P<0.001). In CE, mast cells were concentrated in the mucosa and submucosa, but in ES mast cells were most numerous in muscularis propria. Compared to CE, in ES tryptase+ PMC were increased in both muscularis mucosa (17 (13-26.5) vs 11 (7-12.8), P=0.01) and propria (40.5 (3155.8) vs 4.5 (4-8.3), P<0.001); chymase+ PMC were increased in muscularis propria (34 (23-48.5) vs 4.5 (2.5-13.3), P<0.001). Eosinophils were found in small numbers (≤7/hpf) in muscularis mucosa and/or lamina propria in only 2/8 CE, but were present in all layers of ES, and peak eosinophil count in muscularis propria was increased compared to CE (11.5 (1.5-39.5) vs 0 (0-0), P=0.002). Conclusions: ES in children show significant structural alterations and inflammation, including obliterative muscularization, and mast cell and eosinophil mural infiltrates, similar to colon strictures in Crohn disease. These data suggest that inflammatory cells may be important in the pathogenesis of ES, and that systemic antiinflammatory therapy may be beneficial in ES.
Su1956 Esophageal Stricture From Magnesium Citrate Powder Ingestion: A Unique Case Angela Assal, Harinder Dhaliwal BACKGROUND AND AIMS: In the United States over 5000 caustic ingestions occur annually and can lead to major complications. There are no reported cases of caustic ingestions secondary to magnesium (Mg) citrate in the medical literature (PubMed, OVID and Google). However, a search of grey literature identified two personal accounts on public forums of ‘inflamed' and ‘burned' esophagus. Here we report an incident of Mg citrate powder ingestion leading to severe esophageal stricturing. CASE: A 40 year old male presented to the Emergency Department after ingestion of Mg citrate powder prescribed by his naturopath for constipation. The patient swallowed one teaspoon of powder (630mg of elemental Mg) without mixing it with 6oz of fluid as instructed. He first presented with dyspnea and chest pain one day post-ingestion; he denied dysphagia. CT scan showed bilateral effusions and esophageal thickening. He was discharged with levofloxacin for aspiration pneumonia. 13 days postingestion he returned with chest pain and dysphagia. The gastroenterology team was consulted and endoscopy (EGD) demonstrated severe LA Grade D esophagitis from 18cm to the gastroesophageal junction. The patient was discharged with oral proton-pump inhibitor (PPI) twice-a-day and plan for repeat EGD in 8 weeks. He presented again 23 days postingestion for progressively worsening dysphagia and odynophagia. His blood work, including Mg level, was normal. Second EGD identified a tight ulcerated stricture 25 cm from the incisors consistent with a caustic stricture. A 6mm CRE wire guided balloon was used to dilate the stricture. Fresh heme and tearing were seen within the stricture so no further dilation was attempted. The patient was admitted to hospital and remained NPO as he could not swallow; intravenous fluids and PPI were initiated. An upper gastrointestinal barium radiograph identified a tapered narrowing initiating at 3cm below the cricopharyngeus, persisting over 13cm and 2mm in diameter (image 1). The first attempt at endoscopic dilation with a 15 Fr Savary bougie was unsuccessful due to significant transmural inflammation with
Su1954 Reversibility of Gastric Mucosal Lesions Induced by Sodium Phosphate Tablets and Characterized by Probe-Based Confocal Laser Endomicroscopy Emmanuel Coron, Marie Dewitte, Philippe Aubert, Nicolas Musquer, Michel Neunlist, Stanislas Bruley des Varannes Background: Bowel preparation is paramount for colonoscopy. The sodium phosphate laxatives used for preparation may potentially induce gastric injuries. Aim: To characterize the effects of a sodium phosphate laxative (Colokit® tablet [CKT]) on the gastric mucosa in an animal model. Methods: Effects on the gastric mucosa of pigs (n=14) were determined 90
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AGA Abstracts
AGA Abstracts
and 12 without Candida infection (Group B) (8 female and 4 male). Blood and esophageal samples from 12 HIV negative healthy volunteers (Group C) (8 female and 4 male) served as normal controls. Immunostained cells were quantified by counting the number of positive cells for each specimen at X400 magnification using a square grid of 0.0625mm2. The number of positive cells was compared between groups using Graph Pad Prism version 5.00 for Windows (Graph Pad software, San Diego, CA, USA) to perform a Mann-Whitney test with the level for significance set at 95%. The blood CD4+ and CD8+ T cell count obtained at the time of endoscopy was analyzed by flow cytometry. The study conformed to the principles of Declaration of Helsinki and Brazilian requirements governing. RESULTS: CD4+ blood T cell were significantly reduced (p<0.0001) and CD8+ blood T cell significantly enhanced in HIV+ patients with Candida esophagitis (Group A) as compared with Group B (p=0.007) and C (p=0.003). This finding was not seen in the histological analysis. Immunohistochemical analysis of the esophageal samples showed a Th17 pattern of cytokines (an interleukin-17+IFNγ− response) in both groups of HIV+ patients (Group A and B) probably induced by IL-6. The median level of IL-17 and IL-6 was significantly higher in Group A (p=0.01) than in Group B (p=0.0006) as shown in Table 1. CONCLUSION: Immunity to esophageal candidiasis in HIV+ patients seems to be dominantly regulated by Th 17 pathway rather than by Th1 cells. The level of CD4+ and CD8+ T cell in blood was not directly correlated with the level in the esophageal mucosa. Also, we did not find a significant difference in the level of esophageal CD4+ T cells between the HIV+ patients and the control group. Lessons of immunity in the mouth and gut mucosa cannot necessarily be applied to the esophagus. Table 1 Blood and esophageal mucosal immunological response in HIV+ patients with and without Candida esophagitis
Su1950 Effect of Celecoxib, a Selective Cycloxygenase-2 Inhibitor, on Acid-Induced HCO3- and Ulcerogenic Responses in Rat Duodenums; A Comparative Study With Conventional Non-Steroidal Anti-Inflammatory Drugs Koji Takeuchi, Kikuko Amagase, Hiroshi Satoh
AGA Abstracts
Su1948 In Vivo, Real Time Non-Invasive Assessment of Gastric Mucosal Injury Using Confocal Laser Endomicroscopy: Focus on Mucosal Microvessels, Progenitor Cells and Mucosal Protection. Direct Comparison With Quantitative Histology and Electron Microscopy. Andrzej S. Tarnawski, Amrita Ahluwalia, Michael K. Jones, Ercheng Zhu
Duodenal HCO3- secretion increases in response to luminal acid. This response is mainly mediated by endogenous prostaglandin E2 (PGE2) derived from cyclooxygenase (COX)-1. However, a recent study showed in cats that rofecoxib, a selective COX-2 inhibitor, by itself damaged the duodenal mucosa, similar to indomethacin, a non- selective COX inhibitor. In the present study, to confirm the importance of COX-1 in the duodenal mucosal defense, we examined the effect of celecoxib, another COX-2 selective inhibitor, on HCO3- and ulcerogenic responses caused by acid in rat duodenums. Methods: Male SD rats were used after 18 h fasting. Under urethane anesthesia, a loop made in the proximal duodenum was perfused with saline, and the HCO3- secretion was measured at pH 7.0 using a pH-stat method and by adding 10 mM HCl. Mucosal acidification was performed by exposing the loop to 10 mM HCl for 10 min. In addition, the duodenal damage was induced by perusing the loop with 100 mM HCl at a flow rate of 1 ml/h for 4 h. Indomethacin (5 mg/kg), loxoprofen (10 mg/kg), SC-560 (a selective COX-1 inhibitor, 3-30 mg/kg) and celecoxib (a selective COX-2 inhibitor, 30 mg/kg) were given ID 1 h before exposure to 10 mM HCl or the onset of 100 mM HCl perfusion. Results: The mucosal acidification stimulated HCO3secretion with an increase of mucosal PGE2 contents in the duodenum. The increase of HCO3- secretion and PGE2 content in response to acidification were significantly inhibited by prior administration of indomethacin. Likewise, a selective COX-1 inhibitor SC-560, dose-dependently inhibited the HCO3- response to acidification; a significant effect was observed at 10 mg/kg, together with the effect on the increased PGE2 production. However, a selective COX-2 inhibitor celecoxib had no effect on either of these responses. RT-PCR analyses showed that COX-2 mRNA was not expressed in the duodenal mucosa after acidification, while COX-1 mRNA was expressed in the normal mucosa and remained unchanged before and after acid treatment. On the other hand, perfusion of the loop with 100 mM HCl for 4 h produced mild hemorrhagic damage, and the severity of these lesions was significantly worsened by indomethacin, loxoprofen and SC-560, while celecoxib did not affect. Conclusion: These results confirmed that COX-1 is a key enzyme responsible for producing PGs involved in the mechanism for the acid-induced HCO3- secretion in the duodenum, and further suggested that COX-1/PGs play a crucial role in the protection of the duodenal mucosa against acid injury.
Background/Aims: Studies of gastric mucosal injury and healing rely on macroscopic and histological assessment of fixed stomach specimens, which may not fully reflect in vivo events. As a result, the cellular targets and real time sequence of gastric mucosal injury are not fully defined. Confocal laser endomicroscopy (CLE), a novel cutting edge technology, has enabled in vivo real-time visualization of mucosal structures at a subcellular resolution. This study was aimed to: 1) assess acute gastric injury in real time using CLE with a focus on mucosal microvessels and progenitor cells; 2) determine whether hydrotalcite (HTL), the newest generation antacid, can protect gastric mucosa against ethanol injury; and, 3) identify the mechanisms involved. Methods: Fischer F344 rats received 1 ml 0.5% fluorescein i.v. followed by intragastric (i.g.) ethanol (1 ml, 50%) or saline. In some rats, either 1 ml of vehicle or HTL (20mg/kg) was given i.g. 30 min prior to ethanol. CLE was performed using the CellvizioLAB LSU F400 with Z ProFlex probe inserted i.g. and CLE images were monitored for 30 min before and after ethanol administration. Studies: 1) CLE imaging of gastric mucosa including epithelium and microvasculature; 2) vascular permeability; 3) mucosal blood flow dynamics; 4) progenitor cell integrity; 5) molecular imaging of VEGFR2 using labeled antibody; 6) detection of i.v. injected bone marrow-derived stem cells (BMDSC) in gastric mucosa. For comparison we performed quantitative histology, and transmission and scanning electron microscopy (EM). Results: At baseline, CLE of rat gastric mucosa demonstrated a normal gastric gland pattern, vasculature, continuous microvascular blood flow and low vascular permeability. Ethanol induced the exfoliation of surface epithelium within 2-3 min, followed by a 550% increase in vascular permeability (p<0.001) at 3-5 min; rupture of microvessels within 5-10 min, extensive extravasation of erythrocytes and vascular stasis. Progenitor cells were severely damaged. Histology and EM confirmed these changes. Pretreatment with HTL reduced ethanol-induced vascular permeability by 55% (p<0.01), preserved blood flow and reduced extent and severity of injury (all p<0.01). In control rats VEGFR2 was visualized in endothelial cells of blood vessels and i.v. injected BMDSC were present in gastric microcirculation. Conclusions: 1) CLE enables precise in vivo, real time analysis of events taking place during gastric mucosal injury and evaluation of mucosal protection. 2) Microvascular injury and increased vascular permeability occur early and precede progenitor cell damage and deep hemorrhagic necrosis. 3) CLE provides a significant advantage over standard histologic and EM assessment, by allowing real time monitoring of in vivo mucosal structure and function, e.g. vascular permeability, and in vivo molecular imaging.
Su1951 Recovery of Gastric Function After Acetium Administration: A 6 Months Study in Atrophic Gastritis Subjects Francesco Di Mario, Hunor Pal Farkas, Francesco Ferrara, Nadia Dal Bo, Tiziana Slongo, Roberto Marcello, Massimo Rugge, Carmelo Scarpignato Background: No consensus from different studies exists regarding the reversibility of atrophic gastritis; however, removal of H pylori from the already atrophic stomach may block further progression of the disease. Although studies report a partial restoration of serum pepsinogen I (sPGI) levels after eradication, it is not clear if this finding reflects gastric mucosal healing on a morphological level. Immune-mediated atrophic changes in the stomach by definition seem to be irreversible. Recently a new compound (L-cystein Acetium, Biohit, Finland) has been proposed for prevention of gastric carcinogenesis in patients with atrophic gastritis, by reducing acetaldehyde (class I human carcinogen) production after food intake. Aims: To assess the changes in gastric function after long term administration of L-cysteine in moderate to severe atrophic gastritis by sPGI and gastrin 17 (sG17). Methods: 30 patients with histological features of moderate-severe body atrophic gastritis and sPGI < 25 μg/L (7 men, mean age 47.9 years, range 27-71) had sPGI and sG17 measured at baseline. In 8 patients autoimmune origin was confirmed by anti-parietal cell antibodies, the rest underwent eradication therapy for Helicobacter pylori infection earlier. Long term oral therapy with Acetium (3x100mg L-cysteine/day before meals) has been initiated and serologic markers were determined at 3 and/or 6 months. Results Mean sPGI levels prior to treatment were 7.9 μg/L, compared to the latest measurements' mean of 11,38 μg/L (p<0.001) reflecting possible increase in active parietal cell mass. On the other hand the mean baseline level of sG17 decreased from 34.4 pmol/L to 26,25 pmol/L (p<0.001) indicating changes in the negative feedback of the regulation transmitted by gastrin. In a few cases, where multiple serological measurements were available, an obvious increasing trend was observed in sPGI levels over time, as well as decrease in sG17 levels. Conclusion: L-cysteine seems to be useful in restoring gastric secretion in subjects with chronic atrophic gastritis both after H.p. eradication and in case of autoimmune etiology.
Su1949 Esophageal Mucosal Integrity Recovers After Laparoscopic Fundoplication in Children With Gastroesophageal Reflux Disease Femke A. Mauritz, Nicolaas Fedde Rinsma, José M. Conchillo, Ernst van Heurn, Peter D. Siersema, David C. van der Zee, Maud van Herwaarden-Lindeboom Background Esophageal intraluminal baseline impedance levels reflect the electrical resistance of the esophageal wall and may serve as an instrument for in vivo evaluation of esophageal mucosal integrity in gastroesophageal reflux disease (GERD) in children. Fundoplication as treatment for GERD aims to reduce (acid) reflux events and restore mucosal integrity. This could be reflected by increased intraluminal baseline impedance levels after operation. The aim of this study was, therefore, to evaluate the effect of laparoscopic fundoplication on mucosal integrity by assessing intraluminal baseline impedance levels before and after fundoplication in children with GERD. Methods Eleven children (5 males) with therapy resistant GERD were included. Median age was 6.5 years (range, 1.6 - 18.2) at the time of laparoscopic fundoplication. Twenty-four hour multichannel intraluminal impedance pH monitoring (MII-pH monitoring) was performed before and 3 months after fundoplication. For every consecutive two hour intervals in the 24-h tracings, intraluminal baseline impedance levels were measured over a period of ≥ 30 seconds not containing any swallows or gastroesophageal reflux episodes. Intraluminal baseline impedance levels were calculated over four segments (3, 5, 7 and 15 cm above the LES) using a specific function incorporated in the analysis software (Ohmega MMS). Results Fundoplication was successful in reducing total acid exposure time (from 11.4% ± 2.3% to 0.9% ± 0.3%, p<0.001) and overall number of reflux episodes (from 106.5 ± 20.1 to 19.7 ± 3.9, p=0.001). The mean distal baseline impedance level increased after fundoplication (from 2423 ± 414 Ω to 3560 ± 328 Ω, p<0.01). Baseline impedance levels also increased at 5 cm (from 2969 ± 428 Ω to 4105 ± 300 Ω, p=0.02) and 7 cm segments (from 3124 ± 459 Ω to 3980 ± 248 Ω, p=0.04) above the LES. In the proximal segment, no significant changes were found after fundoplication (from 3099 ± 341 Ω to 3621 ± 172 Ω, p=0.12). Prior to fundoplication, mean distal baseline impedance level showed a negative correlation with acid exposure time (r: -0.78, p<0.01). We also observed a gradual increase of intraluminal baseline impedance levels from the distal to the proximal impedance segment in the esophagus, reflecting the distribution of acid exposure in the esophagus. Conclusion Reduction of acid exposure and number of reflux episodes by laparoscopic fundoplication leads to a significant increase in intraluminal baseline impedance levels in children with GERD, which may indicate repair of mucosal integrity and success of therapy.
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Su1952 TH17 Pathway Promotes Mucosal Host Defense Against Esophageal Candidiasis in HIV-Infected Patients Ana Luiza Werneck-Silva, Carla Pagliari, Rosely A. Patzina, Wellington F. da Silva, Luciane K. Galo, Maria Irma S. Duarte INTRODUCTION: Esophageal candidiasis is the most common opportunistic infection in the GI tract in HIV+ patients. Host defense mechanisms against Candida albicans vary by anatomical site, as HIV+ patients are primarily susceptible to oropharyngeal and esophageal, but not vaginal or disseminated candidiasis. Although immunity to C. albicans was long considered to be mediated by Th1 cells, new data in both rodent and in humans have revealed a role for the Th17 lineage, a subset of effector T cells that are localized at the mucosal level, including the gut mucosa. To date, the relative contribution(s) of Th1 and Th17 responses in esophageal candidiasis have not been defined. AIMS: To determine the role of mucosal T cell immunity and IL-17 pathway against esophageal Candida infection in HIV+ patients. METHODS: Immunohistochemistry to CD4+ and CD8+ T cells, INFγ, TGFβ, IL-6 and IL-17 were performed in esophageal histological samples obtained from endoscopy in 28 HIV+, 16 with Candida esophagitis (Group A) (6 female and 10 male)
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min, 24 and 72 hours (H24, H72) after direct application of CKT and placebo tablets (PLT). Characterizations included endoscopic, probe-based confocal laser endomicroscopy, histological examinations and ex vivo permeability measurements on mucosal resection. Results: At 90 min, enanthema was observed in 57% of animals at CKT sites. At H24 two pigs showed enanthema and one pig an aphtous lesion at the CKT site. At PLT sites, the aspect was normal at 90 min but enanthema was observed in 22% of animals at H24. At H72, no lesion was identifiable in any animal for any site. At 90 min, CKT sites showed a significant increase in epithelial irregularity and crypt pit intensity, which remained unchanged at H24. PLT induced a slight but significant increase in epithelial irregularity and architectural disorganization. At H72, semi quantitative scores and crypt pit intensity were significantly reduced and similar to H0. At PLT sites, crypt pit and intercryptic intensities remained unchanged. Mucosal thickness at CKT sites was similar to that at CTRL sites. Fundic paracellular permeability was not changed at CKT sites. Conclusions: Direct and prolonged gastric application of Colokit® tablets in pigs induces acute superficial macroscopic and microscopic injuries in some animals. These lesions are spontaneously reversible in less than 72 hours. Su1955 Inactivation of Carcinogenic Acetaldehyde by Slowly L-Cysteine Releasing Capsule Formulation in Gastric Juice of PPI Treated Volunteers After IntraGastric Infusion of Ethanol Ryuhei Maejima, Katsunori Iijima, Panu H. Hendolin, Pertti Kaihovaara, Lea I. Paloheimo, Tomoyuki Koike, Tooru Shimosegawa, Kari J. Syrjänen, Mikko Salaspuro INTRODUCTION: Acetaldehyde (ACH) associated with alcoholic beverages has been classified as carcinogenic (Group 1) to humans by IARC/WHO. Gastric mucosa, many microbes colonizing acid-free or hypochlorhydric stomach as well as many Helicobacter pylori strains possess alcohol dehydrogenase activity capable of locally producing ACH from ethanol. ACH produced from ethanol in oral cavity and esophagus contributes to local ACH exposure in the upper digestive tract. Atrophic gastritis and H. pylori infection associated with enhanced exposure to locally formed ACH are the two most important risk factors for gastric cancer. Furthermore, ethanol-derived ACH may contribute through gastro-esophageal reflux to the pathogenesis of esophageal squamous cell carcinoma. Aldehyde dehydrogenase (ALDH2), a major enzyme responsible for ACH elimination, is genetically deficient among 30-50% of Eastern Asians. In alcohol drinkers, ALDH2-deficiency associates strongly with increased risk for upper digestive tract cancers through exposure to ethanol-derived carcinogenic ACH via saliva. Capsule that slowly releases L-cysteine in the stomach converting ACH to inactive 4-methyltiazolidine-2-carboxylic acid (MTCA) has been recently implicated in prevention of gastric carcinogenesis among patients with atrophic gastritis. AIMS: To assess the effect of PPI-treatment on gastric juice ACH levels, following an intra-gastric infusion of 15% ethanol, with or without administration of L-cysteine. The final results will be stratified according to the individual ALDH2 genotypes. METHODS: The final study cohort comprises ten ALDH2-active and ten ALDH2-deficient H. pylori negative healthy volunteers. Through a nasogastric tube 15% ethanol (0.5g/kg) is infused into the stomach. 5ml of gastric aspirates and saliva are collected at 30-min intervals up to 120 min. The first aspirations are done before and after 7-day administration of proton pump inhibitor (PPI, rabeprazole 10mg b.i.d.) (experiment 1 and 2). After 3 more days on PPI, aspiration is repeated with 200mg of slowly releasing L-cysteine administered before ethanol infusion (experiment 3). RESULTS: Thus far, 11 volunteers have completed the three experiments. PPI treatment increased gastric juice ACH levels by an average of 50% for 2 hours (p=0.0428 at 30min.). After intake of L-cysteine free ACH levels in gastric juice decreased by a mean of 60% up to 120min (p=0.005, p=0.003, p=0.03 at 30-,60- and 90min, respectively). The possible effect of ALDH2 polymorphism on gastric juice ACH levels will be elucidated when all 20 subjects have completed the study protocol. CONCLUSIONS: The results confirm the previous reports on PPI treatment as a trigger of free ACH levels in gastric juice. An average of 60% of the ethanol-derived carcinogenic ACH in the stomach can be inactivated by concomitant administration of slowly releasing L-cysteine.
Group A= HIV+ patients with esophageal Candidiasis Group B= HIV+ patients without Candidiasis Group C= HIV negative healthy controls without Candidasis Su1953 Esophageal Strictures in Children Contain Focal Obliterative Muscularization and Mural Inflammation Margaret H. Collins, Eileen S. Alexander, Lisa J. Martin, Tommie M. Grotjan, Juan P. Abonia, Vincent A. Mukkada, Philip E. Putnam, Marc E. Rothenberg Background: Esophageal strictures (ES) in children cause significant morbidity, but are not well characterized pathologically. We report unique histopathologic analyses of surgically resected pediatric ES and control esophagi (CE--obtained at autopsy). Methods: Slides of ES (n=10) and CE (n=8) identified in our pathology database (1/1968-4/2013) were reviewed; additional slides from paraffin blocks containing transmural sections were stained with actin (1A4, 1:1,000, Cell Marque, Rocklin, CA), tryptase (predilute, Ventana, Tucson, AZ), or chymase (1:50, Abd Serotech, Raleigh, NC) antibodies. Muscularis mucosa and propria thicknesses were measured in millimeters in architecturally-intact well-oriented areas using an eyepiece reticle. Peak mast cell (PMC) and eosinophil counts were obtained from the most inflamed high power field (hpf) viewed at 400X (0.3 mm2). Results were expressed as median, lower and upper quartiles. Wilcoxon Rank Sums non-parametric t-test was used to compare groups and P≤0.05 was considered significant. Results: Age at sample collection did not differ between CE and ES patients (2.5 (0.5-4.9) vs 3.7 (2.5-10.5) years, P=0.2). Causes of ES were caustic ingestion (5/10—mean time from ingestion to resection was 10 months), reflux (2/10), congenital abnormality and possible eosinophilic esophagitis (1/10), and unknown (2/10). All ES showed significant structural alterations compared to CE. Specifically, lamina propria, muscularis mucosa, and submucosa were replaced by fibromuscular foci (obliterative muscularization) containing actin+ fibers which were continuous with muscularis propria. In areas of preserved architecture, compared to CE ES displayed significantly thickened muscle layers: muscularis mucosa (1.2 (0.65-1.49) vs 0.19 (0.100.33) mm, P=0.002) and propria (3.1 (2.68-4.4) vs 1.2 (0.92 - 1.68) mm, P<0.001). In CE, mast cells were concentrated in the mucosa and submucosa, but in ES mast cells were most numerous in muscularis propria. Compared to CE, in ES tryptase+ PMC were increased in both muscularis mucosa (17 (13-26.5) vs 11 (7-12.8), P=0.01) and propria (40.5 (3155.8) vs 4.5 (4-8.3), P<0.001); chymase+ PMC were increased in muscularis propria (34 (23-48.5) vs 4.5 (2.5-13.3), P<0.001). Eosinophils were found in small numbers (≤7/hpf) in muscularis mucosa and/or lamina propria in only 2/8 CE, but were present in all layers of ES, and peak eosinophil count in muscularis propria was increased compared to CE (11.5 (1.5-39.5) vs 0 (0-0), P=0.002). Conclusions: ES in children show significant structural alterations and inflammation, including obliterative muscularization, and mast cell and eosinophil mural infiltrates, similar to colon strictures in Crohn disease. These data suggest that inflammatory cells may be important in the pathogenesis of ES, and that systemic antiinflammatory therapy may be beneficial in ES.
Su1956 Esophageal Stricture From Magnesium Citrate Powder Ingestion: A Unique Case Angela Assal, Harinder Dhaliwal BACKGROUND AND AIMS: In the United States over 5000 caustic ingestions occur annually and can lead to major complications. There are no reported cases of caustic ingestions secondary to magnesium (Mg) citrate in the medical literature (PubMed, OVID and Google). However, a search of grey literature identified two personal accounts on public forums of ‘inflamed' and ‘burned' esophagus. Here we report an incident of Mg citrate powder ingestion leading to severe esophageal stricturing. CASE: A 40 year old male presented to the Emergency Department after ingestion of Mg citrate powder prescribed by his naturopath for constipation. The patient swallowed one teaspoon of powder (630mg of elemental Mg) without mixing it with 6oz of fluid as instructed. He first presented with dyspnea and chest pain one day post-ingestion; he denied dysphagia. CT scan showed bilateral effusions and esophageal thickening. He was discharged with levofloxacin for aspiration pneumonia. 13 days postingestion he returned with chest pain and dysphagia. The gastroenterology team was consulted and endoscopy (EGD) demonstrated severe LA Grade D esophagitis from 18cm to the gastroesophageal junction. The patient was discharged with oral proton-pump inhibitor (PPI) twice-a-day and plan for repeat EGD in 8 weeks. He presented again 23 days postingestion for progressively worsening dysphagia and odynophagia. His blood work, including Mg level, was normal. Second EGD identified a tight ulcerated stricture 25 cm from the incisors consistent with a caustic stricture. A 6mm CRE wire guided balloon was used to dilate the stricture. Fresh heme and tearing were seen within the stricture so no further dilation was attempted. The patient was admitted to hospital and remained NPO as he could not swallow; intravenous fluids and PPI were initiated. An upper gastrointestinal barium radiograph identified a tapered narrowing initiating at 3cm below the cricopharyngeus, persisting over 13cm and 2mm in diameter (image 1). The first attempt at endoscopic dilation with a 15 Fr Savary bougie was unsuccessful due to significant transmural inflammation with
Su1954 Reversibility of Gastric Mucosal Lesions Induced by Sodium Phosphate Tablets and Characterized by Probe-Based Confocal Laser Endomicroscopy Emmanuel Coron, Marie Dewitte, Philippe Aubert, Nicolas Musquer, Michel Neunlist, Stanislas Bruley des Varannes Background: Bowel preparation is paramount for colonoscopy. The sodium phosphate laxatives used for preparation may potentially induce gastric injuries. Aim: To characterize the effects of a sodium phosphate laxative (Colokit® tablet [CKT]) on the gastric mucosa in an animal model. Methods: Effects on the gastric mucosa of pigs (n=14) were determined 90
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and 12 without Candida infection (Group B) (8 female and 4 male). Blood and esophageal samples from 12 HIV negative healthy volunteers (Group C) (8 female and 4 male) served as normal controls. Immunostained cells were quantified by counting the number of positive cells for each specimen at X400 magnification using a square grid of 0.0625mm2. The number of positive cells was compared between groups using Graph Pad Prism version 5.00 for Windows (Graph Pad software, San Diego, CA, USA) to perform a Mann-Whitney test with the level for significance set at 95%. The blood CD4+ and CD8+ T cell count obtained at the time of endoscopy was analyzed by flow cytometry. The study conformed to the principles of Declaration of Helsinki and Brazilian requirements governing. RESULTS: CD4+ blood T cell were significantly reduced (p<0.0001) and CD8+ blood T cell significantly enhanced in HIV+ patients with Candida esophagitis (Group A) as compared with Group B (p=0.007) and C (p=0.003). This finding was not seen in the histological analysis. Immunohistochemical analysis of the esophageal samples showed a Th17 pattern of cytokines (an interleukin-17+IFNγ− response) in both groups of HIV+ patients (Group A and B) probably induced by IL-6. The median level of IL-17 and IL-6 was significantly higher in Group A (p=0.01) than in Group B (p=0.0006) as shown in Table 1. CONCLUSION: Immunity to esophageal candidiasis in HIV+ patients seems to be dominantly regulated by Th 17 pathway rather than by Th1 cells. The level of CD4+ and CD8+ T cell in blood was not directly correlated with the level in the esophageal mucosa. Also, we did not find a significant difference in the level of esophageal CD4+ T cells between the HIV+ patients and the control group. Lessons of immunity in the mouth and gut mucosa cannot necessarily be applied to the esophagus. Table 1 Blood and esophageal mucosal immunological response in HIV+ patients with and without Candida esophagitis