Mo1227 Cathelicidin Mimic Ceragenin CSA13 Modulates Clostridium difficile Associated Colitis and Toxin a Mediated Enteritis in Mice

clinical characteristics and post-IMR GI symptoms, recipients with a prior diagnosis of IBS appear more likely to experience post-IMR loose stools. Careful pre-IMR clinical assessment and counseling would help optimize post-IMR outcome and patient satisfaction. Further large prospective study is needed to delineate the effect of SIBO on IMR outcomes. Mo1226 MRI Scans Should Be Used to Monitor the Effects of Anti-TNF Therapy When Treating Perianal Crohn's Fistulas Nuha A. Yassin, Alan Askari, Linda Ferrari, Janindra Warusavitarne, Omar Faiz, Arun Gupta, Robin K. Phillips, Ailsa Hart Background and Aims Fistulising perianal Crohn's disease (CD) is a challenging condition to treat and a multidisciplinary approach to treatment is frequently required. Little is known regarding the long-term efficacy of anti-TNF therapy for this group of patients. We evaluated the clinical and radiological outcomes and the effects of biological therapy on our cohort of patients. Methods A local database of 180 consecutive patients with Crohn's disease treated at our institution between 2005 and 2014 was established. Data on patient demographics and relevant outcomes were collated from medical, electronic and radiological reports. Results Patients underwent Infliximab therapy (61%), Adalimumab therapy (6%) or switched between the two (33%) for the treatment of the perianal fistulas. Clinical remission was noted in 47% of patients with a classification of a simple fistula, and 22% of those with a complex fistula (p<0.01). Radiological remission however was noted in 28% of patients with a simple fistula and 5% of those with a complex fistula (p<0.01) After a median follow-up period of 52 months (range 1-163), 32% of patients were in clinical remission, 74% of patients had a clinical response to treatment and the recurrence rate after remission was 12%. Radiological remission was noted in 14% of patients, response in 62% of patients and recurrence of 4.7% over a median of 37 months (range 3-101) MRI follow-up. The median time to clinical remission was 21 months (IQR 11-36), and time to radiological remission was 20 months (IQR 1-88). Whereas the median time to clinical response was 25 (IQR 18.8-31.2), and radiological response median time was 19 months (IQR 13-24). Factors influencing the time to clinical response were fistula duration (p=0.03), and the current use of immunomodulators (p=0.02). Patients who did not have a Montreal classification of L1 disease were 2.68 times more likely to achieve clinical remission (CI=1.23-5.86, p=0.01), as were those who did not suffer with L3 disease (OR=2.47, CI=1.05-5.78). Having no proctitis at the start of biological therapy predicts a twofold increase in the likelihood of clinical remission in this group of patients (CI=1.01-6.18, p=0.04) Conclusions About three-quarters of patients with fistulising perianal Crohn's disease had clinical response to biological therapy, whereas two-third had a radiological response. Twelve percent of the patients had a clinical recurrence after remission, whereas only 4.7% had radiological recurrence after remission on MRI scanning. A time delay is noted between clinical and radiological response to treatment. Response to anti-TNF therapy for fistulising perianal Crohn's disease should be monitored with regular MRI imaging as an adjunct to clinical follow-up. Mo1227 Cathelicidin Mimic Ceragenin CSA13 Modulates Clostridium difficile Associated Colitis and Toxin a Mediated Enteritis in Mice Bowei Su, Sally Ghali, Samantha Ho, Jung Eun Lee, Diana Hoang-Ngoc Tran, Xinhua Chen, Ciaran P. Kelly, Hon Wai Koon Background: C. difficile mediates intestinal inflammation by releasing toxin A (TxA), and cathelicidin has been shown by our group to mediate anti-inflammatory effects against TxA. However cathelicidin is a peptide that can be degraded easily, limiting its potential for clinical uses. A new non-peptide cathelicidin mimic called Ceragenin (CSA13) has been recently developed as an experimental drug. We hypothesize that CSA13 can be used to treat or prevent C. difficile infection. Here we investigated if CSA13 improves survival and inhibits inflammation. Materials and Methods: CSA13 was provided by N8 Medical, Inc. (Columbus, Ohio). (Primary infection study): c57BL/6 mice were infected with C. difficile (VPI10463 strain, 10(4) cfu). CSA13 (10mg/kg) was administered via enema every day (day 0-3). (Relapse study): The mice were infected with C. difficile (10(5) cfu) followed by oral vancomycin administration every day (day 0-2). Then the vancomycin administration was discontinued (day 3-5) and CSA13 was injected subcutaneously (50mg/kg, day 6 and 8). (TxA ileal loop study): TxA (10ug) was incubated with or without CSA13 (10mg/kg) in the ileal loop of mice for 4 hours. (In vitro study): Mouse Raw264.7 macrophages were exposed to CSA13 for 4 hours followed by incubation with TxA for 4 hours. Results: C. difficile infection caused 25% mortality and colonic damages with elevated histology scores, and increased colonic TNFalpha protein levels after 3 days. CSA13 prevented all mortality and significantly inhibited C. difficile-induced colonic damages, as shown by the reduced histology scores (3.3+/-0.3 vs 1.8+/-0.3, mean+/-sem, p=0.02) and colonic TNFalpha protein levels (4.4+/-0.2 vs. 2.4+/-0.2 pg/microg protein, p=0.001). Subcutaneous CSA13 administration increased the survival rate of C. difficile infected mice in the first 3 days, compared to the vehicle group (50% vs. 20% survival). Relapse occurred after withdrawal of vancomycin administration to C. difficile infected mice. The survival rate on day 10 was 33%, but the survival rate was increased to 47% in the CSA13 treated group. Body weight of vancomycinmediated relapse group on day 7 was reduced to (81+/-2.2%) as it was partially reversed by subcutaneous CSA13 administration (89+/-1.9%, p=0.0175). TxA induced TNFalpha protein expression in ileal loops, and CSA13 significantly reduced the TxA-induced ileal TNFalpha expression (p=0.0008). CSA13 (1-10 microM) also significantly reduced TxAinduced TNFalpha protein expression in mouse macrophages (p=0.0001). However, CSA13 (up to 10 microM) did not have significant antimicrobial effects against C. difficile bacterium (VPI10463 strain) within 3 hours of incubation. Conclusions: CSA13 can serve as a novel reagent to treat primary and relapses of C. difficile infection in mice via its potent antiinflammatory effects rather than antimicrobial effects.

Mo1225 Factors Associated With C. difficile Negative Gastrointestinal Symptoms After Intestinal Microbiome Restoration Jessica R. Allegretti, Matthew J. Hamilton, Joshua R. Korzenik, Walter W. Chan Background: Fecal Microbiota Transplantation (FMT) or Intestinal Microbiome Restoration (IMR) is a safe and effective treatment for recurrent C.difficile infection (CDI). The procedure is performed via colonoscopy often with stool infusion into the terminal ileum (TI). Many patients report bloating or loose stool post-IMR despite resolution of CDI. Screening for small intestinal bacteria overgrowth (SIBO) is not routinely performed pre-IMR. The effect of donor or recipient SIBO status on outcome of IMR and the cause of post-IMR gastrointestinal (GI) symptoms remain unclear. Aims: 1) To evaluate the effect of pre-procedure SIBO status on IMR outcome. 2) To assess the relationship between post-IMR GI symptoms and donor or recipient clinical characteristics. Methods: This was a prospective cohort study of adult patients with recurrent or refractory CDI referred for IMR at a tertiary care center. In addition to routine pre-IMR screening for infections and thorough medical histories, all donors and recipients underwent standard lactulose breath test (LBT) for SIBO prior to IMR. IMR was performed via colonoscopy. Presence of GI symptoms (bloating, loose stools, constipation) and CDI recurrence were assessed at 12-week follow-up post-IMR. Fisher's exact test for binary variables and student t-test for continuous variables were performed for statistical analyses. Results: Twenty-six subjects [13 recipients (mean age: 55 yrs, 85% women) and 13 recipient-selected donors (mean age: 50 yrs, 62% women)] enrolled in the study. Eight (62%) IMRs involved stool infusion into TI. Three (23%) recipients and 4 (31%) donors had positive LBT pre-IMR. Twelve (92%) recipients had resolution of CDI at 12-week follow-up post-IMR. The lone CDI recurrence was found in a recipient with positive LBT pre-IMR. Two (15%) patients reported bloating post-IMR, while 5 (38%) noted loose stools. Neither donor nor recipient pre-IMR LBT result was associated with development of post-IMR GI symptoms. There was a trend towards increased loose stools among recipients with pre-IMR diagnosis of irritable bowel syndrome (IBS) (75% vs 25%, p=0.07). No other clinical characteristics were associated with post-IMR GI symptoms. Conclusion: IMR is effective and well tolerated for recurrent CDI. Positive pre-IMR LBT in recipients or asymptomatic donors does not lead to worse IMR outcomes including CDI recurrence or GI symptoms. Although no statistically significant relationship was found between patient

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AGA Abstracts

AGA Abstracts

GI fluid 5-ASA levels were noted within 1 h after ingesting all 3 mesalamine products; Ac5-ASA levels increased after 1 h for Pentasa and Apriso and 3 h for Lialda. Prominent 5ASA and Ac-5-ASA release after Pentasa was observed at all GI sites (including gastric). Gastric 5-ASA levels were >170-fold higher after Pentasa vs. Lialda. Peak small bowel GI 5-ASA (Figure 1) and Ac-5-ASA (not shown) levels were 15 to 1000+ fold lower for Lialda vs. Pentasa and Apriso, emphasizing greater colon release for Lialda. In addition, peak GI Ac-5-ASA levels were seen earlier with Pentasa (4.0+2.0 h) vs. Apriso (7.0+0.0 h) and Lialda (6.0+1.4 h). Plasma 5-ASA and Ac-5-ASA levels were lower vs. GI fluids consistent with luminal actions (Table 1). As in GI fluids, plasma 5-ASA and Ac-5-ASA appeared earliest for Pentasa and latest for Lialda. Peak plasma levels occurred 12 h after Lialda, reflecting again mostly colon absorption. Conclusions: Using novel multiport catheters to aspirate GI fluids for regional drug release analysis, we showed variable time-dependent appearance and absorption of 3 mesalamine products. Release of 5-ASA and its metabolite occurred earliest and most proximally with Pentasa (including gastric release). Small bowel release and absorption were slower and more distal with Apriso and were minimal with Lialda. Such innovative in vivo techniques will be used to validate in vitro dissolution methods and support computational models for future processes that are applicable to developing luminally-acting and extended-release drugs. This research was funded by FDA grants HHSF223201000082C and HHSF223201300460A.