propria (LP) and peripheral blood (PB) mononuclear (MN) cells of patients with IBD as well as non-IBD controls. Methods: LPMCs (n=87) and PBMCs (n=88) were obtained from non-IBD controls (LP n=18, PB n=27), uninflamed UC (UC-; LP n=13, PB n=6), inflamed UC (UC+; LP n=19, PB n=21), uninflamed CD (CD-; LP n=24, PB n=9), and inflamed CD (CD+; LP n=13, PB n=25) patients, cryopreserved and thawed in batches. Cells were stimu- lated with PMA/ionomycin, stained with a panel of CYTOF antibodies, and data analyzed with both automated clustering and manual gating. Results: LP differences distinguish inflamed IBD (IBD+) from uninflamed IBD (IBD-) and from non-IBD: IBD LP is enriched with HLADR+CD38+ (“activated”) T cells (26.4% IBD+ > 13.9% IBD- > 5.9% non-IBD, out of total CD45+ cells [p=5.6e-07]). Tregs (1.10% IBD+ > 0.6% IBD- > 0.26% non-IBD [p= 0.00067]) and IL-1b+ macrophages (0.31% IBD+, 0.07% IBD-, 0.23% non-IBD [p=2.1e- 07]) were increased in IBD+. Additionally, IBD- had fewer DCs than IBD+ and non-IBD (4.6% IBD+, 2.4% IBD-, 5.8% non-IBD [p=0.00024]). LP differences distinguish UC+ from CD+: UC+ LP has fewer T cells compared to CD+ (UC+ 59% vs. CD+ 69% [p=0.013]) with a trend towards more B cells. Among T cells, CD4+ are more abundant in UC+ than in CD+ and non-IBD (UC+ 19% vs. CD+ 14% [p=0.026] vs. 14% non-IBD [p=0.024]). There are more “activated” CD4+ T cells in UC+ that express IL-17 over IFNg with the opposite being true in CD+ (ratio 1.55 IL-17:IFNg in UC+ vs. 0.27 IL17:IFNg in CD+ [p=0.0017]). CD+ LP has greater IL-1b+ CD123+DCs compared to UC+ and non-IBD (0.026% UC+, 0.082% CD+, 0.034% non-IBD [p=0.011]). The unique PB difference distinguishing CD+ from UC+ and non-IBD was an increase in IL-1b+ monocytes in CD+ (0.24% UC+, 0.69% CD+, 0.29% non-IBD [p=0.009]). Conclusions: CYTOF analysis of LP and PB reveals differ- ences associated with colonic inflammation as well as immune characteristics that differentiate UC and CD. Whereas differences in the LP involve populations of activated T cells, Tregs, and innate immune cells, significant differences in the PB are restricted to innate cells. Certain signatures, such as greater abundance of IL-1b+ monocytes in the PB of CD+ patients, could potentially be used to distinguish inflammatory disease states in the periphery and identify new avenues of diagnostic and treatment approaches. Figure 1. VISNE density heatmaps demonstrate global differences in T cell population abundance in LP across IBD disease types and inflammation status in a representative subset of patients included in the abstract (a). Area defined by asterisk (*) is diminished in controls but significantly more abundant in inflamed tissue (both UC and CD). This area corresponds to both CD4+ and CD8+ T cells that co-express HLADR and CD38 (as demonstrated by the marker heatmaps in b). Manual analysis of HLADR+CD38+ T cells as a percent of total CD45+ cells reveals that this population is most abundant in inflamed IBD > uninflamed IBD > control tissue (p=5.6e-07). Su1886 SACRAL NERVE STIMULATION INHIBITS THE MAPK/NF-KB SIGNALING PATHWAY AND PROMOTES TREG-TH1/17 CELL BALANCE IN TNBS- INDUCED INFLAMMATION IN RATS Yan Meng, Payam Gharibani, Alimujiang Maisiyiti, Yiling Zhang, Jiande Chen Background & Aims: 2,4,6-trinitrobenzene sulfonic acid (TNBS) is known to induce inflam- mation through triggering the MAPK/NF-kB pathway and activation of T helper cells. Recently, sacral nerve stimulation (SNS) was reported to exert an anti-inflammatory effect on TNBS-induced colitis. The aim of this study was to investigate whether the SNS anti- inflammatory effect was mediated via the MAPK/NF-kB signaling pathway and/or balancing Th1/17-Treg cells. Meanwhile, we also explored if SNS could alter self-renewal of neurons in myenteric plexus. Methods: Forty male Sprague-Dawley (SD) rats were implanted wire electrodes unilaterally at sacral nerve (S3). One week later, the rats were administrated with TNBS intra-rectally. Five days later, 20 of the rats were treated with SNS 1 hour daily for 10 days with the optimized parameters derived from previous studies and the other 20 rats were treated with sham-SNS (exactly the same setting but SNS at 0mA). Additional 20 rats were treated with intra-rectal injection of saline, serving as controls. Animal behaviors and various inflammatory factors were assessed by the disease activity index (DAI), macroscopic score, microscopic score, fluorescence-activated cell sorter and western blot. Longitudinal muscle myenteric plexus (LMMP) was studied by immunohistochemistry. Results: 1) Com- pared with saline, the TNBS treatment substantially induced inflammation, increased the percentage of Th1 cells (P=0.03), Th17 cells (P=0.02) and Treg cells (P=0.04); it also increased p-ERK/ERK by 2.3 folds (P<0.01) and p-JNK/JNK by 20.7 folds (P<0.001) and increased nuclear translation of NF-κB p65 by 3.5 folds (P<0.01); 2) compared to sham- SNS, SNS significantly decreased DAI (area under the curve: 64.3±3.8 vs. 49.5±3.2, P<0.01), macroscopic scores (5.85±0.9 vs. 2.55±0.6, P=0.03) and microscopic scores (4.6±1.1 vs. 2.7±0.8, P=0.04) and normalized the colon length; 3) in colon tissues, compared with sham- SNS, SNS reduced the percentage of Th1 cells (8.87±2.32% to 5.40±1.39%, P=0.04) and Th17 cells (12.35±1.61% to 9.75±1.17%, P=0.04) but increased Treg cells (15.73±2.81% to 20.15±2.24%, P=0.03); 4) SNS reduced the percentage of the phosphorylation of MAPKs compared to Sham-SNS (p-ERK/ERK: 22.5%, P=0.03; p-JNK/JNK: 25.6%, P=0.04) and prevented the nuclear translocation of NF-κB p65 by 40.7% (P=0.02, vs. sham-SNS); 5) the percentage of choline acetyltransferase (ChAT) neurons were decreased by TNBS but reversed by SNS (19.06±2.07% to 25.68±3.56%, P=0.02). The percentage of nitric oxide synthase (NOS) neurons was increased by TNBS but decreased by SNS (17.21±1.27% to 13.34±1.63%, P=0.03). Conclusions: SNS is effective in inhibiting colon inflammation S-649 AGA Abstracts through the inhibition of the MAPK/NF-kB pathway, balancing of Th1/Th17-Treg cells, and also improving the LMMP neuronal self-renewal and regeneration. Figure.1 The percentage of Th1 (IFN-γ),Th17 (IL-17) and Treg (Foxp3) cells in colon tissues of TNBS-induced colitis in rats. SNS: sacral nerve stimulation. (*p<0.05 vs. Control;#p<0.05 vs. Sham-SNS) Figure.2 The percentage of the phosphorylation of MAPKs (p-ERK/ERK; p-JNK/JNK) and the nuclear translocation of NF-κB p65 in colon tissues of TNBS-induced colitis in rats. RI: relative intensity; SNS: sacral nerve stimulation. (*p<0.05 vs. Control;#p<0.05 vs. Sham-SNS) Su1887 ENDOGENOUS OPIOIDS IN CHRONIC COLITIS INDUCE SUSTAINED ANTINOCICEPTIVE EFFECT VIA AN OPIOID RECEPTOR - COMPARTMENTALIZED ENDOSOMAL SIGNALING PATHWAY Nestor N. Jiménez-Vargas, Lih En Tiah, Pradeep Rajasekhar, Holly Yeatman, Meritxell Canals, David E. Reed, Alan E. Lomax, Nigel W. Bunnett, Daniel P. Poole, Michelle L. Halls, Stephen Vanner Background: Studies have shown that colonic tissue from inflammatory bowel disease (IBD) patients and pre-clinical models of IBD have an increased number of CD4+T cells releasing endogenous opioids. We have shown that these endogenous opioids in the colons of mice AGA Abstracts