Figure 2: Depicts the levels of ELP-3 in UC, and the differences between HD and UC patients with either a normal, mild, or moderate to severe endoscopic score based on their MES. Significance illustrated as follows: p<0.05 *. P<0.01 **, p<0.001 *** Tu1792 BIOMARKERS OF ELASTIN DEGRADATION IS ASSOCIATED WITH CLINICALLY AND BIOCHEMICALLY ACTIVE DISEASE IN CROHN'S DISEASE Martin Pehrsson, Viktor Domislovic, Morten Asser Karsdal, Marko Brinar, Ana Barisic, Zeljko Krznaric, Tina Manon-Jensen, Joachim Høg Mortensen Background: In Crohn’s disease (CD) the extensive and potentially transmural inflammation results in increased activity of both matrix metalloproteases (MMPs) and serine proteases, causing a higher degree of intestinal tissue remodeling. This increased proteolytic activity could potentially cause degradation and loss of function of mechanical and functional matrix proteins, such as elastin. Therefore, we sought to investigate the association between biomarkers of elastin degradation and the disease activity in CD patients. Methods: 72 CD patients and 29 healthy donors (HD) were included in the study. Disease activity was determined according to the Crohn’s disease activity index score (CDAI>150) and/or a fecal calprotectin (fCALP>250). Additionally, CD patients were endoscopically assessed according to the simple endoscopic score (SES) for CD. Different protease derived biomarkers of elastin degradation: protease-3 (ELP-3), MMP-7 (ELM-7), and cathepsin-G (EL-CG) was measured in serum by ELISA. One-way ANOVA (Kruskal-Wallis) was applied for the statistical analysis. Results: The levels of ELP-3 was significantly elevated in active CD when compared with the HD (p<0.001), and inactive CD (p<0.01). Levels of EL-G were significantly elevated when comparing active CD and HD (p<0.05), with the same result observed for the levels of EL-CG when comparing active CD and the HD (p<0.05). Endoscopically, ELP-3 was shown significantly elevated in moderate to severe CD patients when compared with the HD (p<0.01). Conclusion: In this study, measurements of the elastin degradation markers was capable of differentiating between CD patients with either a clinically active or biochemi- cally active disease, with the biomarker levels being significantly highest in the patients with an active disease. This was also the case when assessing endoscopic disease activity, where the protease-3 derived biomarker levels were highest in patients of moderate to severe disease activity. As such, the data provides indications of the beneficial use of these serum biomarkers as additional disease activity assessment tools for CD patients. S-1163 AGA Abstracts Figure 1: Depicts the levels of the elastin degradation markers in CD, and the differences between HD and CD patients with either inactive or active disease based on a CDAI >150 and/or fCALP >250. The lower part of the figure depicts the levels of ELP-3 in CD, and the differences between HD and CD patients in remission, with mild, or moderate to severe CD based on their SES score. Significance illustrated as follows: p<0.05 *, p<0.01 **, and p<0.001 ***. Tu1793 BILE ACID MALABSORPTION AND OUTCOMES AFTER TREATMENT WITH COLESEVELAM IN MICROSCOPIC COLITIS Srishti Saha, Edward V. Loftus, William J. Tremaine, Sahil Khanna, Leslie J. Donato, Michael Camilleri, Darrell S. Pardi Background: Bile acid malabsorption (BAM) is hypothesized to contribute to diarrhea in patients with microscopic colitis (MC). Reports of BAM in MC in human studies are inconsis- tent, and vary based on methods used to diagnose BAM. We conducted a pilot study to assess the response of MC to colesevelam, a bile-acid sequestrant, and explore the correlation between a serum marker of BAM and treatment response. Methods: An open-label study was conducted in adults with MC [diarrhea: >3 bowel movements (BM) daily for >6weeks with histologic evidence of MC). Patients with inflammatory bowel disease, celiac disease, major gastrointestinal surgery, history of bowel obstruction, chronic liver disease, hypertri- glyceridemia, current pregnancy or lactation, antibiotic use within 4 weeks or other medica- tions (immunosuppressants, oral anticoagulants, drugs affecting GI transit, bile acid binders, cholesterol lowering agents) within 1 week were excluded. Fasting serum 7 -hydroxy-4- cholesten-3-one (C4) level was collected prior to starting study drug and on the morning after the last dose. All patients were given colesevelam 625mg 3 tabs PO BID for 10 days. Daily symptom diary was maintained for 8 days pre- and post- treatment. Clinical remission was defined as mean stool frequency <3 BM/day and <1 watery BM/day while on treatment (Hjortswang criteria). Other outcomes assessed were change in diarrhea (BM/d), change in C4 level, and correlation between baseline C4 and treatment response. Patients who responded were offered the drug clinically after completion of the study. Descriptive statistics, Wilcoxon signed rank test and univariate logistic regression were used as appropriate. p<0.05 was considered statistically significant. Results: Eight patients were included; 1 patient did not provide a symptom diary and was excluded from further analysis. Median age was 62 years (range, 39-70); 100% were female. Three patients had collagenous colitis and 4 had lymphocytic colitis. Median time from diagnosis was 8 months (range, 0-70). Prior treatments received were: anti-diarrheals in 42.8% (3), corticosteroids in 42.8% (3) and azathioprine in 14.3% (1); 71.4% (5) had partial response to prior treatment and 14.3% (1) were steroid- dependent. All patients had active disease at baseline; post-treatment, 57.1% (4) achieved remission. On univariate logistic regression, baseline C4 level predicted remission post- treatment (odds ratio, 1.6; 95% CI, 1.01-59.4; p=0.02). The effect of colesevelam on symp- toms is shown in Table 1. Four patients experienced adverse events (Table 2). Overall, 71.4% (5) continued with colesevelam after completion of the study. Conclusion: In this small open-label pilot study, colesevelam improved symptoms of MC and baseline C4 level predicted response. Our results indicate a possible role for treatment of BAM in MC and further studies are warranted. AGA Abstracts