as HSF1 from HSP90 allowing HSF1 to perform it's functions in the cell. Applying these molecular insights to IBD, we find 17-AAG use profoundly suppresses development of DSS- induced colitis. In another model of colitis, adoptive transfer of CD4+CD45Rbhi cells to Rag deficient mice leads to colitis at ~50 days, and compared with DMSO-treated controls, mice treated with 17-AAG did not develop colitis, gained weight(p<0.05), and had negligible diarrhea and near normal histology. In addition, flow cytometry showed increased absolute numbers of CD4+Foxp3+ cells in the lymph nodes and increased expression of Treg related genes, CTLA-4, and IL-10. Lastly, We noted an anti-inflammatory effect on effector T cells themselves including a decrease in IL-17 expression as well as decreases in Th1 cytokines. In summary, HSP90i(17-AAG) use can regulate Foxp3-dependent functions and enhance Treg suppression with biologically important consequences. In addition, HSP90i can inhibit Th1 and Th17 cell cytokine secretion. Dissecting the complex interactions of the heat shock response including HSF1, HSP90 , HSP70 and others, presents but one of several potential ways to pharmacologically manipulate Treg cells In Vitro and In Vivo, with likely future beneficial consequences for the therapy of IBD. M1747 Cationic Amino Acid Transporter 2 Has an Important Role in Regulation of Proinflammatory Mediators in DSS Colitis Lori A. Coburn, Kshipra Singh, Rupesh Chaturvedi, Brooks Scull, Daniel P. Barry, Mary K. Washington, Keith T. Wilson Background: L-arginine (L-Arg) is the substrate for both inducible nitric oxide synthase and arginase, which are upregulated in IBD and in mouse colitis models. L-Arg uptake by cells is mediated by cationic amino acid transporter (CAT) proteins; CAT2 is the inducible form in macrophages. We have shown that mice lacking CAT2 have exacerbated DSS colitis compared to wild-type (WT) mice. Our aim was to determine if L-Arg supplementation reduces DSS colitis and if CAT2 is required for any potential benefits. Methods: Male C57BL/ 6 WT and CAT2-/- mice were given 4% DSS for 6 days followed by 4 - 7 days of 1% L- Arg (DSS/L-Arg) or H2O only. Body weights were measured daily. At sacrifice, colons were assessed for length and weight. Histology was assessed by a validated scoring system including depth and percent involvement with inflammation and crypt damage (0-40 scale). Serum and tissue L-Arg was measured by HPLC. Tissue chemokines and cytokines were measured by Bio-Plex magnetic bead assay. Results: In WT mice supplemented with L-Arg there was significantly less body weight loss at days 7-10 than mice receiving H2O only (p < 0.05 - 0.001). The decrease in colon length and increase in colon weight caused by DSS were significantly attenuated in the DSS/L-Arg group (p < 0.005). However, there was no significant improvement in histologic injury at this time point. Serum and tissue levels of L-Arg were elevated in the DSS/H20 mice and intriguingly, only tissue L-Arg levels were increased in the DSS/L-Arg mice (p < 0.01). Analysis of tissue lysates by magnetic bead assay revealed a significant increase in the pro-inflammatory cytokines IL-1α, IL-1β, IL-6, IL-17, G-CSF, and the chemokines KC, MCP-1, MIP-1α, and RANTES; these increases were significantly decreased by L-Arg supplementation (p < 0.01 for all). When CAT2-/- mice were treated with DSS or DSS/L-Arg, the improvement in body weight loss, colon weight and colon length with L-Arg was lost. There was a significant decrease in survival in CAT2-/- mice beginning on day 6 with DSS that was not abrogated with L-Arg supplementation. In contrast in WT mice, L-Arg completely prevented death (p < 0.01). Conclusions: L-Arg supplementation is effective in improving clinical and biochemical pro-inflammatory para- meters in DSS colitis and this protection is lost in CAT2-/- mice. Histologic changes appear to be underestimated by the early mortality in mice receiving DSS only. Our findings indicate the benefits of L-Arg supplementation are dependent on functional CAT2 expression. CAT2 mediated L-Arg uptake is integral to the regulation of proinflammatory mediators in DSS col- itis. M1748 Resveratrol as Anti-Inflammatory and Anti-Fibrotic Therapy in Peptidoglycan- Polysaccharide Rat Model of Crohn's Disease Kinan Rahal, Jeremy Adler, Phyllissa Schmiedlin-Ren, Muhammad Dhanani, Victoria Sultani, Ellen M. Zimmermann Resveratrol is a phytoalexin that is abundant in skin of red grapes, peanuts and blueberries and has anti-inflammatory and anti-fibrotic effects. We previously showed that resveratrol decreased proliferation of rat intestinal smooth muscle cells and decreased collagen I synthesis In Vitro. We hypothesize that resveratrol will decrease inflammation and fibrosis in an animal model of Crohn's disease. Methods: Peptidoglycan-polysaccharide (PG-PS) or control HSA was injected into the bowel wall of Lewis rats at laparotomy. PG-PS rats develop chronic inflammation and fibrosis approximately d14 post-injection. Resveratrol treatment with 20 mg/kg, 40 mg/kg and 100 mg/kg (n=5-6/group in 3 experiments) was begun on d1 post- injection. Gross gut score was determined at 28 days. Trichrome sections of cecum were measured for collagen content by MatLab image colorimetric analysis. Quantitative real-time PCR for procollagen I & III, IGF-I, TGFβ, TNFα, IL1, and IL6 was performed on cecal tissue. Results: PG-PS rats (vehicle treated) developed more fibrosis than HSA rats by all measurements: gross gut score (p<0.001), collagen image colorimetric analysis (p=0.04), procollagen I (p=0.002), and procollagen III (p=0.002). PG-PS rats treated with the lower resveratrol doses showed a trend toward decreased gross gut score, inflammatory cytokines and collagen that did not reach statistical significance. PG-PS rats treated with 100 mg/kg resveratrol expressed decreased inflammatory cytokines, IL1 (3.50 ± 1.08 vs. 10.79 ± 1.88; resveratrol vs. vehicle, respectively; p=0.005), IL6 (16.51 ± 8.90 vs. 46.83 ± 8.65; p=0.02), TNFα (0.80 ± 0.14 vs. 1.89 ± 0.22; p=0.002). TGFβ was less in the resveratrol group (2.24 ± 0.37 vs. 4.06 ± 0.58; p=0.01). There was a trend in gross gut score (13.80 ± 2.29 vs. 18.25 ± 0.85; p=0.07) and tissue collagen by image analysis that did not reach significance. Procollagen I (6.66 ± 2.44 vs. 13.39 ± 3.18; p=0.07), procollagen III (5.85 ± 2.48 vs. 9.55 ± 2.20; p=0.16) and IGF-I (4.30 ± 1.15 vs. 6.82 ± 2.55; p=0.18) also demonstrated a trend. Conclusion: Resveratrol decreased inflammatory cytokines and TGFβ in PG-PS model of Crohn's disease and demonstrates a promising trend in decreasing tissue fibrosis. These finding may have clinical application in inflammatory bowel disease. S-411 AGA Abstracts M1749 Aquaporin Expression is Down-Regulated in a Murine Model of Colitis and Improved by Apple Polyphenol Extracts Maria T. Ribecco, Giovanna Mazzone, Concetta Tuccillo, Giulia Graziani, Vincenzo Fogliano, Nicola Caporaso, Giuseppe D'Argenio Background and Aim: Colitis is associated with alterations in electrolyte and water transport. These changes give rise to some of the symptoms experienced by patients with colitis. Alterations in fluid flux may also contribute to increased susceptibility to mucosal injury. Recently, endogenous water channel proteins (aquaporins; AQPs), have been identified in colonic tissue. We have recently shown that apple polyphenol extracts (APE) are able to prevent NSAIDs injury to the rat stomach. In the present study the expression of AQP8 as an index of colonic fluid flux was examined in a murine model of colitis; furthermore, we investigate whether rectal administration of APE can ameliorate colonic inflammation and influence AQP8 expression in the colon. Materials and methods: TNBS dissolved in 0.25 mL of 50% ethanol (v/v) was instilled into the rat colon through a rectal catheter . For the normal control rats, saline was used instead of the TNBS solution. Twelve rats with TNBS- induced colitis were divided in two groups (n = 6 in each group) and treated with rectal administration of 1 mL/die of APE 10-4M or vehicle daily for 14 days. Cyclooxygenase-2 (COX-2), tumour necrosis factor alpha (TNF-α) as stress response enzyme and cytokine, AQP8 as an index of colonic fluid flux were assessed by RT-PCR and western blot analyses. AQP8 tissue localisation was examined by immunohistochemistry. Results 1) APE signific- antly reduced TNBS colitis both macroscopically (lesion score: 4.7 + 1.9 vs 1.7. + 1.0, p<0.05) and microscopically (10.9 + 3.1 vs 4.5 + 1.5, p<0.05); 2) TNBS colitis was associated with increased mRNA and protein expression of COX-2 and TNF-α and this increase was counteracted by APE. The expression of AQP8 mRNA was significantly decreased in TNBS rats and restored by APE treatment. These changes in mRNA expression correlated with AQP8 protein expression as determined by Western blotting and immunohistochemistry. AQP8 was expressed in the surface and upper crypt epithelium and also displayed cytoplasmic staining pattern in normal tissue. Following the induction of colitis, AQP8 staining decreased in intensity and became quite undetectable. Treatment with APE restored a staining pattern comparable with that of normal control tissue. Conclusion: colonic injury in rat is associated with a down-regulation in AQP8 expression while treatment with Ape results in reduced inflammation and restoration of AQP8 expression. Our findings show that APE, protecting the colon against alterations in fluid flux, may also contribute to reduce mucosal susceptibility to injury. M1750 Westernized High-Fat Diet Accelerates Development of Dextran Sulfate Sodium-Induced Colitis in Mice and Supplementation of Heme Aggravates the Disease Course Elise M. van der Logt, Tjasso Blokzijl, Roelof Van der Meer, Maikel P. Peppelenbosch, Klaas Nico Faber, Gerard Dijkstra Introduction: Dietary factors, like fat and red meat, may play a role in the development of inflammatory bowel diseases (IBD), e.g. Crohn's disease and Ulcerative colitis (UC). Moreover, the incidence of IBD is high/rising in populations that consume westernized diets. Red meat contains high levels of heme, which can induce heme-oxygenase 1 (HO-1), an enzyme that protects the cell from oxidative stress. HO-1 converts heme into metabolites with antioxidant- and anti-inflammatory properties. Pharmaceutical inhibition of HO-1 leads to increased epithelial damage in an animal of colitis, suggesting that HO-1 may improve the disease course of UC. Methods: We investigated the effects of a westernized high-fat diet supplemented with or without heme, on dextran sulfate sodium (DSS)-induced colitis in mice. During an acclimatization period of one week, female Balb/c mice were fed either a control- or a westernized-diet. This was followed by one week of pre-treatment with either control-, westernized- or westernized diet supplemented with 0.5 μmol/g heme. Subsequently, all three groups were subdivided in a group that was exposed to 4% DSS in the drinking water and another group that was maintained with normal drinking water. Bodyweight was recorded daily. Colon length, colon histology, HO-1 staining, inflammation- (myeloperoxidase, iNOS, cytokines) and epithelial- (villin) markers were studied. Results: DSS induced a significant reduction in body weight in control diet-fed mice after 4 days. In westernized diet-fed mice this was already observed after 2 days. Supplementation of heme aggravated the disease course of DSS-induced colitis, indicated by increased weight loss, more severe diarrhea and decreased physical activity. DSS-treated mice on control- or westernized diet were sacrificed on day 6 and 4, respectively. Shortening of the colon due to DSS-induced colitis was not influenced by the addition of heme. Supplementation of heme to the westernized-diet led to an increased HO-1 staining of the epithelial lining of the colon, but this was not associated with a change in the level of inflammation- and epithelial markers (mRNA expression of iNOS, cytokine and villin). Except for myeoloperoxidase activity, which was increased compared to westernized-diet fed mice. Conclusion: A westernized diet accelerates DSS- induced colitis in mice and supplementation of heme aggravates the disease course. Therefore, effects of this diet should be investigated in IBD patients. M1751 Oxygen Sensor Inhibition Attenuates TNF-α Induced Intestinal Epithelial Damage by Hypoxia Inducible Factor (HIF) 1-Dependent Repression of Fas- Associated Death Domain Protein (Fadd) Pieter Hindryckx, Martine De Vos, Peggy Jacques, Liesbeth Ferdinande, Harald Peeters, Brigitta M. Brinkman, Peter Vandenabeele, Dirk Elewaut, Debby Laukens Background and aims Oxygen sensor inhibitors stabilize Hypoxia-Inducible Factor (HIF), which has barrier protective activity in the gut. As the inflammatory cytokine Tumor Necrosis Factor alpha (TNF α) contributes to inflammatory bowel disease (IBD) in part by comprom- ising intestinal epithelial barrier integrity, we hypothesized that oxygen sensor-inhibition may have beneficial effects in TNF α induced intestinal pathology. Methods Littermate C57BL/6 TNFΔARE/+ mice, which spontaneously develop chronic terminal ileitis, were AGA Abstracts