897 Teduglutide, a Novel GLP-2 Analogue, Decreases Fecal Wet Weight, Sodium and Potassium Excretion in Short Bowel Syndrome (SBS) Patients Dependent On Parenteral Nutrition (PN)

897 Teduglutide, a Novel GLP-2 Analogue, Decreases Fecal Wet Weight, Sodium and Potassium Excretion in Short Bowel Syndrome (SBS) Patients Dependent On Parenteral Nutrition (PN) Palle B. Jeppesen, Kelly A. Tappenden, Richard Gilroy, Stephen J. O'Keefe, Douglas L. Seidner, Nancy McGraw, Henry Chu, Bernard Messing Background: Given the morbidities and healthcare burden associated with intestinal failure, therapies to enhance intestinal function could reduce PN dependence of inflicted individuals. Teduglutide, a degradation resistant analogue of the intestinotrophic peptide glucagon-like peptide-2, is a clinical candidate for such a therapy. Aim: A 72-hour balance sub-study was conducted as part of a larger 24-week efficacy study to quantify the ability of teduglutide to increase absorption, decrease fecal wet weight and decrease electrolyte losses. Methods: At baseline, weeks 8 and 24, patients were given food and beverages standardized to each patient's diet. Absolute absorption was calculated as the weight difference between oral intake and fecal excretion. Relative absorption was absolute absorption divided by oral intake multiplied by 100. 21 patients (4 placebo, 10 teduglutide 0.05 mg/kg/d and 7 teduglutide 0.10 mg/kg/d) were included: 10 male, 50±14 years, post duodenal remnant small bowel 57±44cm, 14 with 70±21% remnant colon, and PN for 7±6 years. Results: Complete data were obtained in 14 of 21 patients (3 placebo, 6 teduglutide 0.05 mg/kg/d, and 5 0.10mg/ kg/d). Pooled results from the two active treatment arms are presented in the table below. No significant changes were observed with placebo. With teduglutide, fecal wet weight decreased by 735±574 g/d at week 24 (p=0.006) compared to baseline. Absolute intestinal absorption increased by 795±618 g/d. In addition, teduglutide decreased fecal sodium by 49±30 (p<0.001) and potassium by 19±22 mmol/d (p=0.003). Conclusion: In this study, teduglutide increased intestinal fluid and electrolyte absorption, resulting in decreased fecal wet weight and sodium and potassium excretion in PN-dependent SBS patients. These preliminary data merit further study in larger patient populations.

895 Increased Gastric Dyplasia and Carcinoma in Gerbils Infected with Helicobacter pylori Strains from Regions of High Versus Low Risk for Gastric Cancer in Colombia Thibaut de Sablet, Rupesh Chaturvedi, Judith Romero-Gallo, M. Blanca Piazuelo, Mary Kay Washington, Alberto G. Delgado, Mohammad Asim, Barbara G. Schneider, Liviu A. Sicinschi, Dawn Israel, Richard M. Peek, Pelayo Correa, Keith T. Wilson Background: In Colombia, individuals from the mountains have a 25-fold greater risk of developing gastric cancer than those living on the coast, despite equally high H. pylori (Hp) prevalence. We have found that Hp clinical isolates from subjects in the high risk region exhibit increased ability to induce oxidative stress in gastric epithelial cells In Vitro, when compared to strains from low risk subjects. We have linked this effect to increased induction of spermine oxidase (SMO), which generates hydrogen peroxide that causes DNA damage. Our aim was to determine if high risk Hp strains have a more potent ability to induce neoplastic changes and SMO In Vivo. Methods: Mongolian gerbils were orally inoculated with Hp clinical isolates. Histology was graded by 2 blinded pathologists. SMO was assessed by immunohistochemistry, and SMO and DNA damage were assessed in the same cells by flow cytometry using an antibody to SMO and 8-oxoguanosine (8-OxoG)-FITC binding peptide. Results: 50 gerbils (n = 5 per group) were inoculated with each of 5 high risk or 5 low risk strains, and sacrificed at 12 weeks. One low risk strain colonized 1/5 gerbils, and another (PZ5009) colonized 5/5 gerbils. One high risk strain (PZ5056) colonized 4/5 gerbils. There was a similar degree of gastritis between the groups, but PZ5056 induced hyperplasia in 2/4 colonized gerbils and dysplasia in one of these. SMO staining was only significantly increased above controls in the gerbil with dysplasia, where there was intense staining of the dysplastic epithelium. We then used gerbil-passaged low risk (PZ5009G) or high risk (PZ5056G; from gerbil with dysplasia) strains to inoculate 10 new gerbils each. When tissues were assessed 14 weeks post-inoculation, gastritis was present in all gerbils, with increased severity with the high risk adapted strain PZ5056G. Most importantly, high grade dysplasia with invasive adenocarcinoma was present in 6/10 gerbils infected with PZ5056G versus only 2/10 with low risk PZ5009G. Flow cytometric analysis of isolated gastric epithelial cells revealed increased SMO expression and DNA damage, and a greater increase in cells that were both SMO+/8-OxoG+ from gerbils infected with PZ5056G vs. PZ5009G. Conclusions: Colombian clinical isolates can colonize gerbils and gerbil-adapted strains induced a high degree of pathology. Both the parental and adapted variants of high risk strain PZ5056 induced more dysplasia and cancer, which was associated with increased SMO expression and oxidative DNA damage. These findings suggest that Hp strains infecting high risk subjects possess an increased ability to induce gastric cancer that is independent of human host factors. 896

p-value~One Way Repeated Measures ANOVA. *~p<0.05 by Bonferoni Method compared to baseline.

Helicobacter pylori Infection of Human Gastric Mucosal Biopsies Inhibits H,KATPase-Dependent Proton Pump Adam J. Smolka, Charles E. Hammond, Craig C. Beeson, Arindam Saha

898

Acute H. pylori infection of human gastric epithelial cells represses transfected H,K-ATPase α subunit (HKα) gene expression through NF-κB p50 homodimer binding to HKα promoter. This process may facilitate gastric colonization by H. pylori and may underlie transient clinical hypochlorhydria. To date, mechanistic studies of H. pylori regulation of HKα expression have utilized the AGS gastric adenocarcinoma cell line transfected with HKα promoter-Luc reporter constructs. However, the AGS cell model is limited by its origin in transformed adenocarcinoma cells that do not express endogenous H,K-ATPase. This precludes measurement of HKα mRNA and protein expression, and proton-pumping activity. In addition, ethical and technical constraints on experimental H. pylori infection of humans has precluded investigation of the time course and dynamics of gastric parietal cell H,K-ATPase activity in response to H. pylori. In this study, we developed an ex vivo model of acute H. pylori infection of human gastric mucosa based on real-time measurement of gastric biopsy extracellular acidification rate (ECAR) using an XF24 Extracellular Flux Analyzer (Seahorse Biosciences, Inc). Finely-divided (~1 mm3, ~5 mg) gastric body biopsies, acquired with IRB approval from patients undergoing endoscopy, were immobilized with Cell-Tak tissue adhesive (one/ well) in the wells of XF24 culture plates. Concurrent measurements of ECAR of each biopsy fragment were then recorded for >2 h under a variety of physiological perturbations. Histamine (1 mM) addition to biopsies (n=3) pre-treated with ethylisopropylamiloride (EIPA, an inhibitor of Na+/H+ exchanger [NHE], 150 μM, n=4) caused significant NHE-independent increases in H+ secretion (from 70 to 110 mpH units/min) compared to vehicle-only controls (n=4). In contrast, biopsies pre-treated with EIPA and omeprazole (10 μM, n=4) or the specific K+-competitive H,K-ATPase inhibitor SCH28080 (50 μM, n=4) showed no sustained

Citrulline: A Potential Predictor of Reductions in Parenteral Nutrition Achieved in Chronic Parenteral Nutrition Dependant Patients with Short Bowel Syndrome (SBS) Treated with Teduglutide Richard Gilroy, Stephen J. O'Keefe, Nancy McGraw, Henry Chu, Khursheed N. Jeejeebhoy, Bernard Messing Parenteral nutrition(PN) allows patients with intestinal failure to survive; however, PN is associated with poor quality of life and life-threatening complications. Teduglutide(TG),an analogue of GLP-2, is an intestinotrophic peptide that increases small intestinal villus height and crypt depth and thereby enterocyte mass. Citrulline, a marker of enterocyte mass, has been demonstrated to increase with TG use. Purpose: The current analysis explores whether changes in citrulline predict reductions in PN in patients dosed at TG 0.05mg/kg/day, a dose associated with significant reductions in PN when compared to placebo. Methods: In a double-blind placebo controlled crossover study, 83 subjects were randomized to TG with 35 to the 0.05 mg/kg/d dose. Twenty-nine subjects at 8 weeks and 26 subjects at 24 weeks with complete data contributed to the analysis. Results: All patients had been on home PN greater than 1 year and 22 had at least part of their colon in continuity. Mean PN at baseline was 9.6+-4.5 L/week and reduced to 6.9 +-4.2 L/week (-28%) at 24 weeks. The mean citrulline at baseline was 18.0 +-10.3 ng/mL, 29.4+-13.7 ng/mL at 8 weeks and 29.6+-16.2 ng/mL at week 24. A clear correlation between increases in citrulline and reductions in PN was seen at 8 weeks (corr -0.481, r=0.0082) and 24 weeks (corr -0.571, r=0.0023).(Images 1 & 2) Conclusion: Significant reductions in PN may be achieved in chronic home PN

A-139

AGA Abstracts

AGA Abstracts

increase in H+ secretion after histamine addition. Inoculation of biopsies with H. pylori(MOI~50, 15 h) not only reduced the basal rate of SCH28080-sensitive H+ secretion compared to controls (from 120 to 50 mpH units/min, n=4), but also markedly attenuated the H+ secretion rate in response to histamine (from 250 to 120 mpH units/min, n=4). The data indicate that statistically-significant rates of secretagogue-dependent, inhibitor-sensitive changes in H,K-ATPase acid secretion can be reproducibly measured in endoscopic biopsies, and provide direct evidence that acute H. pylori inoculation of human gastric body biopsies causes down-regulation of both basal and histamine-stimulated acid secretion.

Global methylation was assessed by a cystosine incorporation assay and by immunohistochemistry (IHC) with anti-5-methylcytosine. Serum folate and B12 were measured by radioimmunoassay and homocysteine was measured by HPLC. Tissue folate levels were assessed by a microbiological assay. RESULTS. There was a significant decrease in CpG methylation in the transgenic mice that correlated with an increasing degree of dysplasia. HF infection resulted in a non significant increase in global methyl content, whereas transgenic mice showed a significant and progressive decrease in methylation from IM to CIS (p<0.01). This gLOM was confirmed by IHC in both epithelial and stromal cells. Serum folate and B12 levels were not significantly different. Serum total homocysteine, however, was significantly elevated in transgenic mice (p<0.001) compared to WT with and without HF infection. Preliminary results suggest that there may be a decreasing trend in tissue folate content between transgenic HF infected and uninfected mice, but not between non-transgenic mice. CONCLUSIONS. These results suggest that neoplastic progression, but not HF-induced inflammatory changes alone, is associated with an early progressive global loss of methylation. These changes correlate with decreasing serum methyl donor levels (increasing tHCY levels) and in preliminary results with tissue methyl donor levels (tissue folate content). The findings indicate that gLOM is an early change in this model of gastric cancer that is specific to neoplasia and does not occur simply as a result of inflammation.