1047a Helicobacter pylori Infection and Chronic Thrombocytopenic Purpura in Children and Adolescents – a Randomized Controlled Trial

AGA Abstracts

randomized to three different antibiotic regimens: 14 days of bid lansoprazole 30mg, amoxicillin 1,000mg, and clarithromycin 500mg (PAC-14); 5 days of bid lansoprazole 30mg and amoxicillin 1,000mg followed by 5 days of bid lansoprazole 30mg, clarithromycin 500mg, and metronidazole 500mg (SQ-10); or 5 days of bid lansoprazole 30mg, amoxicillin 1,000mg, and clarithromycin 500mg, and metronidazole 500mg (PACM-5). We evaluated eradication by UBT 6-8 weeks after randomization. Odds ratios (OR) for eradication (combining the three treatments) and 95% confidence intervals (CI) were calculated for age, sex, education, study center, compliance with treatment, body mass index, smoking, alcohol consumption, number of children in the house, household crowding index, history of antibiotic use and dyspeptic symptoms. A multivariate logistic regression model including all significant variables was developed. Results: We obtained a follow-up UBT on 1414 participants (96%). Adherence to therapy (<=20% of pills returned) was 93%. Overall eradication was 80%. In a multivariate model including all subjects with a UBT test at follow-up, the probability of eradication at 6 weeks was significantly increased among subjects complying with treatment (OR=4.4, p<0.0001). The relative odds for eradication increased with age (OR=1.14 per 10 year increase, p=0.04), was higher for men than women (OR=1.6, p=0.006) and less common among current drinkers (OR= 0.6, p=0.03). Eradication also varied significantly by study center, with the highest rates observed in Honduras, Costa Rica and Chile. Conclusions: Our results indicate that treatment adherence is very important in eradication programs. Differences in response by center and epidemiologic variables can provide clues on transmission, early reinfection, bacterial strains and antibiotic resistance or metabolism. Although in our study the number of children in the house was not associated with treatment outcome, higher treatment success among men and older participants could be related to the fact that those groups are less likely to be close to infected children in the home and deserves further study. Support: Bill & Melinda Gates Foundation grant #43930 and National Cancer Institute grant # CA037429.

1047a Helicobacter pylori Infection and Chronic Thrombocytopenic Purpura in Children and Adolescents - a Randomized Controlled Trial Elisabete Kawakami, Helena S. Hanai Brito, Josefina P. Braga, Rodrigo S. Machado, Sandra R. Loggetto, Celso Granato There is scientific evidence of an association between Helicobacter pylori infection and chronic Immune Thrombocytopenic Purpura (cITP) in adult patients. However, this association has rarely been studied in pediatric patients. Objective. To evaluate the effect of H. pylori eradication in the remission of thrombocytopenia in children with cITP. Patients and Methods. 85/100 cITP patients (Mean age 11.1y±4.3; M/F=0.98:1) from 4 Pediatric Hematology Centers in São Paulo City, Brazil, were included. The diagnosis of cITP was based on American Society of Hematology (ASH) guidelines (1996): platelet count above 150X109/ L, lasting more than 6 months. H. pylori infection was defined by 2 locally validated positive tests: 13C-urea breath test (Sensitivity: 96.8% CI95%: 93.8-99.4%; Specificity: 93.2% CI95%: 81.8-97.7%) and monoclonal stool antigen test (Sensitivity: 100% CI95%: 92.7-100%; Specificity: 97.8% CI95%: 94.7-99%). CagA and VacA IgG antibodies were investigated by immunoblotting in serum samples of all infected patients. Randomization: 22 Infected patients were randomized into 2 groups: Group I. 11 H. pylori treatment group; Group II. 11 H. pylori non treatment group (called later for H. pylori treatment in case of low platelet count persistence) and Group III. 63 H. pylori uninfected patients. A standard triple therapy for H. pylori with amoxicillin, clarithromycin, furazolidone and/or doxycycline, and a proton pump inhibitor for 14 days ( 92.3% of eradication). The 13C-urea breath test was repeated after 4 to 8 weeks to verify H. pylori eradication. Platelet (PLT) count was determined in all patients at 3, 6 and 12 months after treatment, or inclusion. PLT response was defined as follows: Complete response: PLT>150 X109/L; Partial response: PLT 50 to 150X109/L, or 20 to 30X109/L above the basal count; Non responders. Results. Mean age, gender and the baseline PLT count ( 63 ± 48 X109/L, 55 ± 42 X109/L and 72 ± 38 X109/L) was similar in 3 groups (p>0,05). At the 6 month follow-up, there was complete PLT response in Group I - 6/10 (60%) versus Group II - 2/10 (20%) (p= 0.068; OR=6.0 CI95%=0.59-76.4); Group I - 6/10 (60%) versus Group III - 09/44 (20.5%) (p=0.013 OR 6,5 95%CI 1.25-36.13). CagA and VacA IgG antibodies were present in almost all infected patients (90% and 80%, respectively). Conclusion. These data suggest that H. pylori eradication can be associated with an increase in platelet count in children with cITP. An investigation of H. pylori and its eradication should be considered in children with cITP. 1048 Mir-214 as a Therapeutic Target in Ulcerative Colitis (UC)-Associated Colon Cancer Christos Polytarchou, Tiziana Palumbo, Maria Hatziapostolou, Charalabos Pothoulakis, Dimitrios Iliopoulos Background & Aims: Patients with inflammatory bowel disease (IBD), have a higher risk for colon cancer development. However, the mechanisms linking chronic inflammation to colon carcinogenesis remain poorly understood. Here, we describe a novel microRNAinflammatory feedback circuit involved in UC-associated colon carcinogenesis. Methods: MicroRNA array analysis was performed in colon cancer tissues derived from patients with no history of IBD (n=37) and from patients with history of UC (n=21). A microRNA inhibitor library, consisting of 350 anti-sense microRNAs, was transfected in HCT-116 cells and NFκB luciferase activity was examined 24h later. MiR-214 was overexpressed in HCT-116 cells and PDLIM2 mRNA levels were assessed by RT-PCR 24h later. 15 mice were treated with azoxymethane (AOM) and 3 cycles of 5% dextran sulfate sodium (DSS) and then LNA-miR214 (5mg/kg) was administered (tail vein, 4 cycles every 5d). Mice were sacrificed and tumor number and size were evaluated. Results: We identified a 16 microRNA signature of UC-associated colon oncogenesis. Specifically, 9 microRNAs were up-regulated, while 7 microRNAs were down-regulated (>2-fold) between sporadic and UC-related colon cancers. MiR-214 was identified as the most up-regulated (11.4-fold) microRNA in colon cancers derived from patients with UC history relative to sporadic colon cancers. MicroRNA high throughput screening revealed that miR-214 inhibition suppressed >90% NF-κB luciferase activity in HCT-116 cells. Bioinformatics analysis revealed that miR-214 has a highly conserved binding site in the 3'UTR of PDLIM2 (PDZ and LIM domain 2) gene. MiR-214 overexpression suppressed 85% PDLIM2 luciferase activity and 6.2-fold PDLIM2 mRNA levels in HCT-116 cells, validating the bioinformatic predictions. In HCT-116 cells inhibition of PDLIM2 expression by siRNA increased NF-κB activity, acting as a nuclear ubiquitin E3 ligase targeting the p65 NF-κB subunit. We also identified that the miR-214/PDLIM2/NFκB pathway was deregulated in tumors derived from AOM/DSS- but not AOM-treated mice, suggesting the specificity of this pathway to UC-associated colon carcinogenesis. Systemic administration of a miR-214 inhibitor suppressed tumor growth (80%) in AOM/DSS-treated mice with no signs of side effects and toxicity in liver, kidney, spleen or heart. Finally, we found that miR-214/PDLIM2/NF-κB pathway was deregulated in 19/21 colon tumors from patients with UC history and 1/37 sporadic colon tumors. Conclusion: We identified for the first time a miR-214-dependent inflammatory circuit specifically activated during UCassociated colon carcinogenesis. Administration of miR-214 inhibitor has therapeutic potential in colon cancer patients with UC history. Acknowledgement: We thank the Translational Pathology Core Laboratory, Department of Pathology at UCLA for providing human colon cancer tissues.

1047 Efficacy of an Investigational Recombinant Antigen Based Vaccine Against a CagA H. pylori Infectious Challenge in Healthy Volunteers Peter Malfertheiner, Michael Selgrad, Thomas Wex, Jan Bornschein, Emanuela Palla, Giuseppe Del Giudice, David Graham, Penny M. Heaton Background and Aim: In a phase I clinical trial the investigational vaccine (IVAC, Novartis) based on CagA, VacA and NAP recombinant H. pylori antigens elicited a significant humoral and T-cell mediated immune response. We tested the efficacy of the IVAC in healthy volunteers exposed to the challenge with a CagA positive H. pylori strain. Material and Methods: 34 healthy H. pylori negative volunteers (18-40 years) were assigned in random order (4:3) to receive three intramuscular doses of the IVAC or placebo at 0, 1 and 2 months. One month after the third vaccination/placebo all subjects received the infective challenge with a well characterized CagA positive isolate, susceptible to all antibiotics used in current eradication regimens. Subjects were monitored with non invasive H. pylori tests on a weekly basis. The primary end point for the presence of infection had been set at 12 weeks post challenge. Upper gastrointestinal endoscopy (UGE) with biopsies for histology, rapid urease test and culture, urea breath test (UBT), fecal antigen test (FAT) and H. pylori serology were performed prior to the challenge and at 12 weeks post challenge. Results: In all but one subjects transient infection was documented by at least one non invasive H. pylori test. All but 2 subjects experienced abdominal symptoms, usually between day 5 and 10 and received symptomatic therapy. At week 12 post challenge 16 of the 34 subjects (47 %) were shown to be infected with H. pylori by at least one test: among culture, histology, UBT or FAT. The rates of infection were similar in the IVAC and placebo group. H. pylori serology including CagA-, VacA-, NAP-antibodies results were positive in 28 of 34 subjects (82 %). In the IVAC group the infection rate was 42% (n=8) and clearance 58% (n=11) compared to the placebo with infection in 53 % (n=8) and 47% (n=7), respectively. All H. pylori positive subjects at week 12 post challenge were successfully treated with the 14 days PPI containing standard triple therapy. Conclusion: Spontaneous clearance of the H. pylori infection occurred spontaneously in approximately 50% of subjects and the rate was similar in the IVAC and placebo groups at week 12. The results of this study provide useful insights for the further development of an H. pylori vaccine.

1049 MicroRNA Library Screen Reveals Mir-410 as Anti-Apoptotic Factor in Cholangiocarcinomas Tiziana Palumbo, George A. Poultsides, Christina Vorvis, Dimitrios Iliopoulos Background and Aims: Cholangiocarcinomas (CLCs) account for the 3% of all gastrointestinal cancers and are characterized by the malignant proliferation of cholangiocytes. The treatment options for CLCs are very limited, thus it is essential to develop novel therapeutic approaches. MicroRNAs are small non-coding RNAs that are involved in CLC pathogenesis, however

AGA Abstracts

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