122 Magnetization Transfer MRI Quantitatively Detects Intestinal Fibrosis in Ex Vivo Human Intestinal Tissue in Crohn's Disease Jeremy Adler, Scott D. Swanson, Alexandros D. Polydorides, Barbara J. McKenna, Hero K. Hussain, Peter D. Higgins, Christopher P. Golembeski, Ellen M. Zimmermann The natural history of Crohn's disease (CD) involves chronic intestinal inflammation leading to fibrosis and stricture formation. Inflammation is readily identified, but no noninvasive method of identifying fibrosis exists. We previously demonstrated that magnetization transfer MRI (mtMRI), a specialized MRI sequence that detects tissue stiffness, quantitatively detects intestinal fibrosis in an animal model of CD. We hypothesize that mtMRI can quantitatively detect fibrosis in intestinal tissue in human CD. METHODS: Patients with CD scheduled for surgical resection of intestinal strictures were identified. Samples of resected intestinal tissue were obtained from the thickest portion of the stricture, and from the least involved tissue margin. Ex vivo tissue was scanned in Varian Inova 2.0 T, 31 cm clear bore system with Acustar S-180 actively shielded gradients at 10 kHz (M sat ) and 100 kHz (M 0 ) off- resonance. MT ratio (MTR) of bowel wall was calculated as 100*(1-M sat /M 0 ). Tissue was sectioned and stained with Mason's trichrome stain and scored for fibrosis by two GI pathologists. The area of collagen per tissue length was determined on trichrome stained sections by image analysis using MatLab. RESULTS: 12 samples of intestinal tissue were obtained from 6 patients with CD undergoing intestinal resection. Mean MTR was 15.6 ± 0.9. The mean histologic fibrosis score was 2.8 ± 0.3. MTR and fibrosis scores did not differ significantly between tissue from mid-stricture and margin. MTR correlated extremely well with tissue fibrosis score (R 2 =0.75; p=0.006) and with MatLab collagen quantification (R 2 = 0.58; p=0.04). The histologic fibrosis score correlated well with the Matlab collagen quanti- fication (R 2 =0.71; p=0.01). CONCLUSION: Magnetization transfer MRI is sensitive to tissue fibrosis in human CD ex vivo tissue and correlates with histologic assessment of fibrosis, and with collagen quantification by image analysis. This is consistent with our findings in an animal model of intestinal fibrosis, and supports our hypothesis that mtMRI can be used to quantitatively detect intestinal fibrosis and could be a useful tool for monitoring the natural history of CD. 123 Endoscopy and MRI-Enteroclysis Are Similarly Powerful to Predict Clinical Outcome in Patients with Crohn's Disease After Ileocolonic Resection Stavroula Koilakou, Johannes Sailer, Philipp Peloschek, Harald Vogelsang, Wolfgang Miehsler, Karl Turetschek, Wolfgang Schima, Walter Reinisch BACKGROUND: Ileocolonoscopy poses the gold standard in the evaluation of postoperative recurrence of Crohn's disease (CD) at the site of the ileocolonic anastomosis. MR enteroclysis is a promising technique for small bowel imaging that combines the advantages of conventional enteroclysis with those of cross-sectional imaging. AIMS: To compare the predictive value of MRI-enteroclysis and colonoscopy, regarding the probability of a clinical recurrence in CD patients, who have undergone ileocolonic resection. PATIENTS AND METHODS: 29 patients were included in the study (16 men and 13 women) with a mean age of 39.7 years (22-69y). The mean time interval between the colonoscopy and the MRI-enteroclysis was 21.4 days and the mean time interval since the index operation 3.7 years. The follow-up period was 2 years. Clinical recurrence was defined as the development of new symptoms or complications requiring a medical or surgical intervention. In 3 patients (10.3%) the radiological evaluation was not possible (metal artefacts in 2 pts, insufficient small bowel distension in 1 pt) and in 8 patients (27.6%) the intubation of the neoterminal ileum was not achievable due to anastomotic stenosis. The endoscopic findings were evaluated according to the Rutgeert's score on a i0-i4 scale by one experienced endoscopist, and the MRI findings were evaluated by 3 qualified radiologists who consented to rate according to a MR0-MR3 scale (MR0=normal, MR1=minimal mucosal changes, MR2=moderate recurrence, MR3= severe recurrence) assessing anastomosis and neoterminal ileum. Endoscopist and radiologists were blinded for the results of each other. RESULTS: By separating patients into subgroups using as a threshold i3 (where i0-i2: absent to moderate and i3-i4: moderate to severe endoscopic lesions) and MR2 respectively (where MR0-MR1: absent to minimal and MR2- MR3: moderate to severe lesions), we found that only 12.5% (1 out of 8) of the patients in the MR0-MR1 group and 10% (1 out of 10) of those in the i0-i2 group had a recurrence during the 2-year follow-up period, whereas 50% of those with MR2-MR3 and 52.6% of those with i3-i4 had an exacerbation at the same period. All of the patients with i4 due to a non-passable anastomosis had moderate to severe MRI findings (MR2-MR3) and 50% of them had a recurrence within the next 2 years. CONCLUSIONS: Our data suggest that colonoscopy and MR-enteroclysis are similarly powerful in predicting the probability of a clinical recurrence in patients who have undergone ileocolonic resection, and might be used interchangeably according to the patient's preference. 124 High Frequency of Proximal Small Bowel Activity in Crohn's Disease Patients with Previous Distal Activity and Persistent Abdominal Complaints Detected with DBE Peter B. Mensink, Zuzana Zelinkova, R. L. West, E. J. Kuipers, Christien J. van der Woude Background: Crohn's disease (CD) patients with involvement of activity in the upper gastroin- testinal tract have a more complicated course of disease. Until the introduction of wireless capsule endoscopy (WCE) and double balloon enteroscopy (DBE), the small bowel (SB) has been ‘unexplored territory', especially concerning mild to moderate activity of CD. In recent years, studies with WCE and DBE showed active SB disease in up to 60% of patients. Aim: To study the involvement of proximal SB activity in CD patients with previously distal activity and persisting complaints, using DBE. Methods: Prospectively, patients with known CD for >3 months and persistent, otherwise unexplained, irritable bowel syndrome (IBS) like symptoms and / or anemia were included in this study. Patients with ileocolonic activity on recent endoscopy were excluded. In all patients visualization of the entire SB was attempted A-21 AGA Abstracts with DBE, using primarily the proximal route, followed by a distal route. Laboratory testing and a Crohn's disease activity index (CDAI) were performed at the time of the DBE. Results: Fifty patients were included: M/F 26/24, median age 46 (23 - 75) yrs, duration of CD median 17 (2 - 44) yrs. In 34 (68 %) patients both routes, in 11 patients only proximal and in 5 patients only the distal DBE route were performed. Visualization of the entire SB was achieved in 2 (4 %) patients. No complications occurred during or after the DBE procedure. In 32 (64 %) pts SB activity of CD was found. In 22 (69%) patients this activity was located proximal to the (neo-) terminal ileum (i.e. out of reach of ileocolonoscopy). The mean CDAI, duration of disease, leukocyte counts and CRP-levels did not differ significantly between patients with or without SB activity. In the SB activity group, the primary localization of CD in the ileo-colonic region was reported significantly more; see Table. Conclusion: Using DBE in CD patients with persistent IBS like symptoms and / or anemia, SB activity is found in 64% of pts. In 2/3 of these patients, this activity is located in the proximal SB, out of reach of the conventional ileocolonoscopy. Other clinical data, nor laboratory assess- ment, are helpful to distinguish between presence or absence of SB activity, with the exception of the primary localization of CD. Relevant clinical and laboratory data * p=0.005 125 Conditional Loss of Hepatocyte Nuclear Factor 4alpha Into the Mouse Colon Epithelium Leads to Chronic Intestinal Inflammation Mathieu Darsigny, Jean-Philippe Babeu, Carine Lussier, Fernand-Pierre Gendron, Emile Levy, Francois Boudreau INTRODUCTION: Hepatocyte nuclear factor 4α (HNF4α) is a master regulator of hepatocyte and pancreatic transcription. Hnf4α deletion in mouse is embryonically lethal with severe defects in visceral endoderm formation, liver maturation and colon development. Although Hnf4α is crucial in the morphological and functional differentiation of the mature hepatic epithelium, the precise role of this transcriptional regulator in the homeostasis of the adult intestinal epithelium has not yet been addressed. AIM: To investigate the role of Hnf4α during the maintenance of colonic functions with the generation of a conditional intestinal epithelial Hnf4α mouse knockout. METHODS AND RESULTS: Conditional deletion of Hnf4 was generated by by crossing floxed Hnf4α mice with the VillinCre transgenic mouse line. Immunolocalisation and real time PCR confirmed that the deletion of Hnf4α was already efficient at post-natal day 1. Surprisingly, mice deficient for intestinal Hnf4α developed normally until the reach of adulthood with an epithelium displaying apparent normal morphological and functional structures. However, Hnf4α conditional knockout mice spon- taneously developed severe colonic inflammation later in life. This was accompanied with relapsing rectal prolapses and the presence of blood in the feces. The colon of mutant mice displayed focal areas of crypt dropout, leucocytes infiltration, lengthening of the colonic crypts, increased level of the epithelial proliferation index (BrdU labelling) and a partial loss of epithelial goblet cells. Mucin-2 gene transcript expression was reduced by more than 60% in mutant mice as determined by real-time PCR. Claudin-4, an important component of the colonic epithelial tight junction, was up-regulated both at the gene transcript and protein level. Finally, a gene profiling analysis among normal and Hnf4α deficient mice identified significant modifications in the expression of few subclasses of genes with known functions in lipid metabolism, mitochondrial activity as well as protection against oxidative stress. CONCLUSION: This work identifies for the first time Hnf4α as a crucial transcriptional modulator of intestinal inflammation. Since Hnf4α is solely expressed by the epithelial compartment of the intestine, our results highlight the crucial importance of epithelial functions into the mucosal protection and maintenance of an adequate equilibrium against inflammatory challenges that are often impaired during inflammatory bowel diseases. (This work was supported by a CIHR) 126 Molecular Identity and Regulation of Na-Adenosine Co-Transport During Chronic Intestinal Inflammation Jeff H. Ye, Steven Coon, Ramesh Kekuda, Uma Sundaram Background: Extracellular adenosine has been shown to suppress and resolve inflammation in animal models of chronic intestinal inflammation. Adenosine is absorbed in the small intestine by Na-dependent adenosine co-transport. Three concentrative nucleoside trans- porters (CNT1-3) have been identified. CNT2 is the primary adenosine transporter. However, the molecular identity and distribution of CNT 2 along the mammalian small intestinal villus-crypt axis is unknown. Furthermore, effect of chronic intestinal inflammation and broad spectrum modulation of intestinal inflammation with steroids on adenosine uptake is also unknown. Aims: Determine the distribution of CNT2 and effect of chronic intestinal inflammation and steroid treatment on CNT2 function. Methods: Chronic intestinal inflam- mation in rabbit was induced by Eimeria magna. Cells were isolated from rabbit ileum by a Ca++ chelation technique. Brush board membrane vesicles (BBMV) were prepared from villus cells by Ca++ precipitation and differential centrifugation. Uptake studies were per- formed by rapid filtration with 3H-adenosine. Total RNA was isolated by TRIzol reagent and used for RTQ-PCR and RT-PCR. Results: RT-PCR demonstrated that CNT2 was present in villus but not in crypt cell. Na-dependent adenosine co-transport was present in villus cell BBM (8.1± 0.9 pmol/ug protein in the presence of Na and 3.0±0.5 in the absence of AGA Abstracts