W1336 Dysbiosis in Diarrhoea-Predominant IBS: Significant Increase in Mucosa- Associated Bacteroides Gareth Parkes, Neil B. Rayment, Barry Hudspith, Liljana Petrovska, Carlo Nunes, Miranda Lomer, Jonathan Brostoff, Kevin Whelan, Jeremy D. Sanderson INTRODUCTION: A number of studies indicate a role for the gastrointestinal microbiota in irritable bowel syndrome (IBS). Studies have shown that patients with IBS have altered gastrointestinal microbiota, although most of these focus on the faecal microbiota. Given the increasing evidence of an inflammatory component to IBS and the proximity of the mucosa-associated microbiota to the colonic epithelium we hypothesise that the mucosa- associated microbiota play a key role in the pathogenesis of IBS. AIMS AND METHODS: To compare the mucosa-associated microbiota between patients with diarrhoea predominant IBS (IBS-D) and controls using fluorescent in situ hybridisation. Patients with IBS-D were identified using Rome III criteria, whilst controls all had a normal bowel habit and without abdominal pain, rectal bleeding or bloating. Rectal biopsies were snap frozen in liquid nitrogen and 6μm sections cut, fixed in 4% paraformaldehyde and permeabilised in 0.2% Triton/PBS. Sections were hybridised overnight with oligonucleotide probes specific for total bacteria (EUB), bacteroides (Bac303), Clostridium coccoides-Eubacterium rectale (EREC482), bifidobacteria (Bif164), Lactobacillus (Lab154) and Escherichia coli. Hybridised mucosa-associated microbiota were viewed under a confocal microscope and were quantified by counting five randomly selected high power fields. RESULTS: Results are summarised in table 1. The mean (SD) age of IBS-D patients was 36.2 (10.1) and controls was 46.1 (11.7). All bacteria were found in a mucinous layer adjacent but not adherent to the epithelium and there were no invasive bacteria seen. There were significantly greater numbers of total mucosa-associated bacteria, highly significant greater numbers of bacteroides and a trend towards greater numbers of clostridia in patients with IBS-D CONCLUSION: This study demonstrates a clear dysbiosis in the mucosa-associated microbiota in diarrhoea predominant IBS. Bacteroides and some species of clostridia are pro-inflammatory. Although we do not know whether this is a primary or secondary phenomenon, it does suggest that the gastrointestinal microbiota may be important in the aetiology of IBS and that modulation of the gut microbiota may be of benefit. Table 1 W1337 Abdominal Symptoms in Patients with Long Qt Syndrome and a “Gain of Function” Mutation in the Nav1.5 Sodium Channel Breg Braak, Tamira K. Klooker, Dirk Scholvinck, Nynke Hofman, Arthur Wilde, Guy E. Boeckxstaens Background & Aims: Patients with the long QT syndrome type 3 (LQTS3) are characterized by “gain of function” mutations in the SCN5A gene encoding for the Nav1.5 sodium channel. As interstitial cells of Cajal and intestinal circular smooth muscle cells express Nav1.5 channels, mutations in the SCN5A gene may possibly lead to abnormalities in gastrointestinal neuromuscular function. Previously we have demonstrated that a ‘loss of function' mutation in the Nav1.5 sodium channel (Brugada patients) does not affect the presence of functional bowel disorders. In the current study we investigated the prevalence of gastrointestinal symptoms in LQTS3 patients with a proven SCN5A “gain of function” mutation. Methods: LQTS3 patients and healthy non-carrier family members (controls) were recruited from a prospective database of the outpatient clinic of the department of Cardiology. A total of 80 subjects were asked to fill out the Gastrointestinal Symptom Rating Scale (GSRS), the Rome III Criteria for irritable bowel syndrome (IBS) and functional dyspepsia (FD) and the Gastrointestinal Quality of Life Index (GIQLI) questionnaire. Results: A total of 59 subjects (74%) returned the questionnaire. 32 LQTS3 patients (44 ± 4 yr, 19 F) with a proven SCN5A mutation (M+), were compared to 27 (47 ± 3 yr, 14F) mutation negative family members. The prevalence of IBS was significantly increased in M+ subjects (odds ratio 4.9, 95% confidence interval: 1.4-17.3, p<0.05). M+ patients reported more often loose stools (odds ratio 5.9, 95% confidence interval: 2.3-15.3, p<0.001) and frequent bowel movements (odds ratio 4.7, 95% confidence interval: 1.8-12.4, p<0.005). The presence of functional dyspepsia and gastrointestinal symptoms such as abdominal pain, epigastric pain, reflux, bloating, urgency and flatulence were not significantly different between the M+ and the controls. Quality of life scores were comparable in both groups (median total score M+: 118.5 ± 14; controls: 122 ± 17, NS). Conclusion: In contrast to ‘loss of function' mutation, subjects with a SCN5A “gain of function” mutation reported an increased prevalence of diarrhea, and have an increased risk of developing IBS. These data suggest a possible role Nav1.5 sodium channels in the development of functional bowel disorders. A-683 AGA Abstracts W1338 Preliminary Observations of Simultaneous Lactulose Breath Testing (LBT) and Scintigraphy in Controls: SIBO Is Not SIBO. Jason Bratten, Stewart Spies, Michael P. Jones Introduction: Recent studies report that many IBS pts may have sxs caused by SIBO. The diagnosis of SIBO in this setting has been made using LBT with non-validated criteria. Using these same criteria, a number of investigators find no differences between IBS pts and ctrls. The aim of this study was to evaluate published criteria for SIBO using simultaneous LBT and scintigraphy in ctrls. Methods: Ctrls were interviewed to exclude the absence of digestive sxs. LBT/scintigraphy was performed using 10gm lactulose in 4oz H2O labeled with 1mCi of Tc-99m sulfur colloid. Breath samples were collected every 15min for 180min. Scintigraphic imaging was continuous. Activity in cecal and splenic flexure regions of interest was calculated every 5 min. LBT were considered positive for SIBO if there was breath H2 production >20ppm; dual breath H2 peaks or an increase in breath H2 within 90min after lactulose ingestion. Results: 11 consecutively recruited ctrls were studied (age(SEM)=26(1)yrs; 7/ 11F). LBT was nondiagnostic in 2/11 due to no rise in breath H2 despite scintigraphic orocecal transit times of 50 and 105 min. 9/11 ctrls had LBT meeting diagnostic criteria for SIBO with incr breath H2 <90min (8/9); breath H2 >20ppm (7/9) and 3/9 ctrls had dual breath H2 peaks. 6/9 ctrls were positive by ≥2 criteria. Orocecal transit times (mean±SEM) measured by LBT (90±15 min) and scintigraphy (83±10 min) were highly correlated (r= 0.95; p<0.0001). Diagnostic rises in breath H2 were consistently associated with rises increases in tracer activity in the cecal area of interest (figure). Conclusion: Abnormalities of LBT reported as diagnostic for SIBO are common in asymptomatic controls. Increases in breath H2, regardless of pattern or timing, occur when the lactulose meal arrives in the large intestine. The published criteria for SIBO by LBT require critical appraisal before its use as a diagnostic tool for SIBO can be advocated. W1339 Use of Colonic and Anorectal Manometry Testing to Evaluate Patients with Constipation Refractory to Medical Therapy Linda Anh B. Nguyen, Amy J. Marincek, William J. Snape Background: Chronic constipation is a common symptom that affects the general population. Most patients respond to medical therapy. Patients who are refractory to medical therapy with colonic inertia are often considered for subtotal colectomy. Aims: 1) Identify the pathophysiologic abnormalities in patients with refractory constipation comparing patients with normal vs. slow transit and 2) Assess whether Sitz marker studies are a reliable indicator for colonic inertia. Patients and Methods: 45 patients (mean age 42.6 years, F=42) with refractory constipation for >6 months were evaluated with a Sitz marker study, colonic manometry (CM) and anorectal manometry (ARM). Patients were characterized as slow transit constipation (STC) if there were >5 markers in the colon on day #5 of the Sitz marker study. CM was performed using a water perfused catheter with 8 side holes placed 15 cm apart. The catheter was placed over a guidewire into the proximal ascending colon at the time of colonoscopy. Tracings were analyzed visually for the presence of high amplitude propagating contractions (HAPC). Recordings were obtained for 1 hour fasting, 30 min after intraluminal bisacodyl 10mg, and 30 min after neostigmine 0.5mg SQ. Patients with an absence of at least 1 HAPC despite stimulation with medications were diagnosed as colonic inertia. ARM and balloon expulsion tests were done to evaluate for sensation and pelvic dyssenergia (PD). Patients with both an abnormal ARM and balloon expulsion test were classified as definite PD. Those with a single abnormality were classified as equivocal. Results: STC was seen in 33/45(73.3%) patients. In patients with STC, CM was abnormal in 21(63.6%) patients. Patients with normal colon transit were more likely to have normal CM studies compared to STC (75.0% vs. 36.4%, p=0.04). Sitz marker studies have a PPV of 42.9% for identifying patients with colonic inertia. PD also occurred in 16(76.2%) patients with colonic inertia. PD was present in 11/12 (91.7%) patients with STC who had a normal CM (1 patient did not have an ARM). In patients with normal colon transit and normal CM, 6 had PD and 3 had normal pelvic floor studies. Patients with normal transit were just as likely to have PD as those with STC (66.7% vs. 84.4%, p=0.23). Conclusions: 1) PD is common in patients with refractory constipation irrespective of colon transit. It is the most common finding in patients with normal colon transit. 2) Colonic inertia was present in 63% of patients with STC. 3) Colon transit studies using Sitz markers are not specific for identifying colonic inertia. Further evaluations should be performed prior to referring patients for surgery. AGA Abstracts