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sdevelopment of GI symptoms and alteration in intestinal permeability. Methods: In a prospec-tive, longitudinal study, urinary metabotyping was conducted on 38 male soldiers (ages 19-23) during combat training and the subsequent rest period using gas chromatography-mass spectrometry. Stress was measured using the perceived stress scale-10 item (PSS-10)questionnaire, while incidence and severity of GI symptoms were assessed using the irritablebowel syndrome symptom severity score (IBS-SSS). Whole gut intestinal permeability wasevaluated by quantifying the 24h urinary excretion of sucralose as a percentage of the orallyadministered 1g dose. Results: PSS-10 stress and IBS-SSS scores were higher during thecombat-training period than at rest [p<0.05]. The urinary metabotype was clearly distinctfrom the rest period [partial least squares discriminant analysis (PLSDA) R2X=0.395, R2Y=0.716, Q2 (cumulative)=0.581], confirming the presence of a unique stress-induced metabo-type. Based on PLSDA, differential metabolites related to combat stress were uncovered (e.g.elevated pyroglutamate and fructose; reduced gut microbial metabolites such as hippurateand m-hydroxyphenylacetate) [p<0.05]. The extent of pyroglutamate upregulation exhibiteda positive correlation with the increase in IBS-SSS in soldiers during combat-training [r=0.5, p<0.05]. Additionally, the rise in fructose levels during combat-training was positivelycorrelated with an increase in intestinal permeability [r=0.5, p<0.05]. Conclusion: Protractedand mixed psychological and physical combat-training stress yielded unique metabolicchanges that corresponded with the incidence and severity of GI symptoms and alterationin intestinal permeability. Taken together, our data provided new insights into the molecularchanges underlying stress-induced GI perturbations which could be exploited for futurebiomarker research or therapeutic strategies.

Su2055

Genetic Variants Producing Less IL-1ra Are Commoner in Irritable BowelSyndrome Than Controls and Patients With Small Intestinal BacterialOvergrowth Have Higher Intestinal Mucosal IL-1 α and β Levels Than ThoseWithout: Evidence for Gut InflammationUday C. Ghoshal, Deepakshi Srivastava, Ujjala Ghoshal, Rama D. Mittal

Background: Low-grade inflammation (controlled by pro and anti-inflammatory molecules),particularly due to small intestinal bacterial overgrowth (SIBO), may cause irritable bowelsyndrome (IBS). In this case-control study, polymorphisms of IL-RA gene (anti-inflammatory)and small intestinal mucosal IL-1α and β levels (pro-inflammatory) in relation to presenceof SIBO were evaluated. Method: 209 IBS patients (Rome III) and 273 healthy controls weregenotyped (PCR) for IL-1RA polymorphism. Mucosal IL-1α and β levels (picogram/milligramof biopsy) were estimated (ELISA) in 82 patients with and without SIBO (>105 CFU/mlupper gut aspirate bacteria). Results: Genotype 1/1 (over-producer of IL1-RA) was infrequentamong patients than controls (111/209 [53.1%] vs 171/273 [62.6%], P=0.007); genotypes1/3 (15 [7.2%] vs 7 [2.6%], P=0.012, O.R=3.301, 95% C.I=1.31-8.35) and 2/3 (both under-producers; 10 [4.8%] vs 2 [0.7%], P=0.009, O.R=7.703, 95% C.I=1.66-35.82) were morefrequent in IBS. 15/82 (18.3%) patients had SIBO. Levels of IL-1α and β were higher inpatients with SIBO than without (IL-1α: 35.4 [20.1-66.8] pg/mg vs 25.5 [4.2-65.3] pg/mg,P<0.001; IL-1β: 206.8 [133.5-365.9] pg/mg vs 93.1 [25.5-197.7] pg/mg, P<0.001) andthose with bloating than without (26.6 [6.1-66.8] pg/mg vs 16.4 [4.2-36.9] pg/mg, P=0.012;96.1 [34.8-365.9] pg/mg vs 60.4 [25.5-235.9] pg/mg, P=0.015). IL-1β was higher in patientswith Bristol stool type 6 as compared to those with type 1-2 (130.5 [64.1-365.9] pg/mg vs92.6 [52.5-135.6] pg/mg, P=0.002) and type 3-5 (130.5 [64.1-365.9] pg/mg vs 94.2 [25.5-306.6] pg/mg, P=0.007). Conclusion: Polymorphisms 1/1 (over-producer of IL-1RA) wasinfrequent and 1/3 and 2/3 (under-producers) frequent in IBS. Increased IL-1α and β levelswere associated with SIBO. Increased IL-1β level was predominantly associated with bloatingand loose stools (Bristol type 6).

Su2056

Novel MRI Techniques and Parameters for Assessing the Impact of Laxativeson the Human ColonKathryn Murray, Luca Marciani, Caroline L. Hoad, Eleanor Cox, Giles A. Major, AdaSilos-Santiago, Caroline B. Kurtz, Kaviani Mehri, Jan A. Paul, Penny A. Gowland, JeffreyJohnston, Robin C. Spiller

BACKGROUND: Chronic constipation affects nearly 20% of the population worldwide buthalf of the patients are dissatisfied with treatment stimulating the recent surge in noveltreatments. Assessing the potential of these novel treatments requires better, patient accept-able, non-invasive techniques to measure key parameters underlying their mode of action.AIMS: To validate our novel MRI parameters for assessing small bowel water content (SBWC),ascending colon water content (ACWC), colonic volumes, colonic T1 and transit, usingispaghula. METHODS: 16 healthy volunteers (4 females, 12 males, ages 19 - 33 years)participated in this double-blind, placebo-controlled, crossover study. They took either 7gof ispaghula, 3.5g of ispaghula or a placebo thrice daily on days 1-6. On day 5 they swallowed5 transit marker pills (TMP) filled with a MR contrast agent and on day 6 were scannedserially for 7 hours. The TMPs were assigned a weighted average position score (WAPS)depending on their location in the bowel. RESULTS: (mean AUC ± SEM) Visible differenceswere seen in the colon of the healthy volunteers after an ispaghula treatment (Figure 1).Relative to the placebo, both the 7g and 3.5g dose of ispaghula increased the ACWCsignificantly (AUC 85±2 L.min and 5±1 L.min respectively v 0.5 ± 0.3 L.min, p< 0.0001),and differences between the 7g and 3.5g dose were also significant (p =0.004). Relative tothe placebo, SBWC was increased significantly by both the 7g dose (53 ± 9 L.min vs placebo27 ± 4 L.min, p=0.0003), and the 3.5 g dose (43 ± 7 L.min, p=0.0035), with significantdifference also between the 7g and 3.5g dose (p=0.02). Ispaghula significantly increased thecolonic volumes and T1, but 24 h WAPS for transit were not significantly changed bytreatment (Table 1). CONCLUSIONS: The volume of water in both the ascending colonand the small bowel are significantly increased by Ispaghula and could be useful biomarkersof laxative effect. Ispaghula also increased colonic T1 and colonic volumes without alteringtransit times suggesting it has little motility stimulating effect. These MRI methods giveinsights on how ispaghula acts on the small bowel and colon and when applied in constipatedpatients will provide novel information on the mechanisms of action.

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Table 1: Comparison of the effect of a 3.5 and 7g ispaghula t.d.s. on ascending (AC)transverse (TC) and descending (DC) colonic volume, colonic T1 and colonic transit (WAPS)relative to a placebo treatment; ** p<0.01, ***p<0.001, ****p<0.0001

Figure 1: A representative example of coronal images of the ascending colon of a volunteerafter a week of (a) 7g of ispaghula, (b) 3.5g of ispaghula and (c) placebo

Su2057

Markers for Visceral Hypersensitivity in Patients With Irritable BowelSyndromeSamefko Ludidi, Zlatan Mujagic, Daisy Jonkers, Daniel Keszthelyi, Martine Hesselink,Joanna Kruimel, José M. Conchillo, Ad Masclee

Background Irritable bowel syndrome (IBS) is a heterogeneous disorder with visceral hyper-sensitivity as an important hallmark. It is not known whether IBS patients with visceralhypersensitivity have different epidemiological and clinical characteristics compared to IBSpatients without visceral hypersensitivity. Aim of our study was to compare in detail a largegroup of hyper- versus normosensitive IBS patients. Materials & Methods IBS patients (RomeIII criteria) have been re recruited for a large-scale cohort study. All patients form this cohortthat underwent a rectal barostat procedure were included and allocated based on those withand without visceral hypersensitivity. Patient demographics, and symptoms were collectedusing questionnaires (GSRS, HADS, SF-36) and a 14-day symptom diary for IBS-relatedsymptoms. A multivariate logistic regression model was used to identify risk markers forhaving visceral hypersensitivity. A P-value < 0.05 was considered statistically significant.Results Ninety-five normosensitive and 93 hypersensitive IBS patients participated in thisstudy. Hypersensitive patients had significantly higher scores for GSRS abdominal pain(3.57±0.13 vs. 3.15±0.13; P<0.05), indigestion (4.24±0.15 vs. 3.69±0.13; P<0.01), reflux(2.29±0.13 vs. 1.73±0.13; P<0.01) and constipation syndrome (3.62±0.17 vs. 2.99±0.14;P<0.01). Also symptom intensity (2.72±0.09 vs. 2.38±0.10; P<0.05), discomfort, (2.61±0.80vs. 2.31±0.09 P<0.05) and mean symptom composite score (14.2±0.40 vs. 12.49±0.48;P<0.01) were significantly increased in the hypersensitive patients. Hypersensitive patientswere characterized by lower age (36.9±1.62 vs. 45.8±1.71; P<0.001), higher female sexprevalence (81.7% vs. 66.0%; P<0.05) and furthermore, the use of SSRI medication wassignificantly increased in the hypersensitive IBS patients (16.1% vs. 6.3%; P<0.05). However,after adjustment for other risk markers, only increasing age was found to be significantlyassociated with lower odds for having hypersensitivity (OR 0.97 (95% CI: 0.94; 0.99)).Conclusion Apart from more severe symptomatology, hypersensitive IBS patients are charac-terized by significantly younger age compared to normosensitve IBS patients.

Su2058

Epigenetic Regulation of COMT by Interleukin-6 in Patients With IrritableBowel SyndromeScott A. Larson, G. Nicholas Verne, QiQi Zhou

Background: Irritable bowel syndrome (IBS) is a common GI disorder that affects up to20% of the US population. In addition to visceral pain, many IBS patients also exhibitsomatic symptoms including migraine headaches and back, temporomandibular joint andmuscle pain. The mechanisms that cause IBS are unclear. Interleukin-6 (IL-6) is altered andcontributes to the progression of human GI disorders. Increased IL-6 production can alterthe expression of mRNAs involved in chronic visceral pain regulation, and moreover canmodulate expression of methylation-dependent genes. Genetic variation in the Catechol-O-Methyltransferase (COMT) gene has been associated with varied perception of multiplenociceptive stimuli, varied susceptibility to chronic pain conditions such as fibromyalgia,migraine, and TMD, and varied need for opioids in pain treatment. This enzyme has a broadset of biological functions including regulation of catecholamine and enkephalin levels. Theobjective of this study was to evaluate COMT expression in colonic tissues of IBS patentswith visceral pain. Methods: We evaluated 38 IBS patients using the FBDSI and visceralpain severity score and 25 controls. A super-array profiling for Human NeurotransmitterReceptors and Regulators (84 genes) were performed using colonic tissues. PCR and ELISAassays were used to confirm the related gene expression and interleukin-6 levels. Methylation-specific PCR was carried out to verify the methylation status in the 5'-promoter region ofCOMT. Results: Two genes were significantly decreased (COMT NPY1R) in IBS patients onsuper-array profiling; significantly decreased COMT expression was present in colon tissuesfrom IBS patients along with the overexpression of IL-6 when compared to controls whichcorrelated with FBDSI and visceral pain severity scores. This supports that the 5'-promoter

region of COMT was noted to be embedded within a CpG island. By methylation-specificPCR, we confirmed that COMT inhibition is associated with IL-6-linked hypermethylationof the COMT promoter. Thus, epigenetic regulation of gene expression by IL-6 can contributeto IBS progression by altering promoter methylation and gene expression of pain-regulatorypathways, such as those involving COMT. Furthermore, the expression level of COMT wassignificantly increased after demethylation treatment by 5-Aza-CdR in colon epithelial cells.Conclusion: Visceral pain in IBS patients may result from decreased COMT expression. IL-6 induced hypermethylation of COMT may be involved and lead to increased severity ofIBS symptoms. These findings provide the basis for an exciting field in which epigenomicmRNAs of colon tissues may be manipulated with potential therapeutic benefits in humanIBS patients.

Su2059

Prevalence of Irritable Bowel Syndrome in Mexico. A Nationwide PopulationBased Study Using the ROME III QuestionnaireMercedes Amieva-Balmori, Arturo Meixueiro, Pedro Canton, Jose Maria Remes-Troche

Introduction: Mexico (United States of Mexico) is a federation comprising thirty-one statesand a Federal District, which in turn are divided into 8 geographic regions. Although irritablebowel syndrome (IBS) is common worldwide, there is uncertainty regarding differences ingeographical regions. In Mexico, some studies have reported that IBS prevalence range from4.4% to 16.0%. However, those studies were performed in small sample and selectedpopulation's. Aim: To estimate the prevalence of IBS in a nationwide Mexican populationusing the Rome III Adult Questionnaire (RIIIAQ) Material and Methods: This study is partof a nationwide project named "SIGAME" (acronym for "Sintomas Gastrointestinales enMexico" in Spanish, or Gastrointestinal Symptoms in Mexicans, in English) which aim is toevaluate the prevalence of gastrointestinal symptoms in a representative population of subjectsthat lives in Mexico. A face to face interview using a specific web application was performedby 73 interviewers, which were residents of one of the 8 geographic regions of the country.The 8 areas are: 1) Northeast (3 states), 2) Northwest (6 states), 3) West (4 states), 4) East(4 states), 5) Central north (5 states), 6) Central south (2 states and Federal district), 7)Southeast (4 states), and 8) Southwest (3 states). All the interviewers had a training for usethe website and the questionnaires. An authorized version of the RIIIAQ Spanish versionwas used and was applied to an open population randomly selected which lives in one ofthe 31 states and the federal district. Sample size was calculated to include at least 500subjects' residents for each of the 8 geographic areas. Results: A total of 2186 have beenevaluated (1309 females, 59.9%, mean age 41.2 ± 14 years). Among the 8 geographic areas587 (26.9%) subjects live in region 3, 444 (20.3%) in region 6, 332 (15.2%) in region 2,234 (10.7%) in region 4, 185 (8.5%) in region 5, 184 (8.4%) in region 1, 111 (5.1%) inregion 7 and 109 (5%) in region 8. Overall prevalence for IBS was 7.6% (n=166, CI 95%6.56-8.78%). Prevalence for IBS among the 8 regions in the country is shown in figure.Women represented 75.2% (n=125) of the patients with IBS for a F:M ratio of 3:1. Therelative frequencies of the IBS subtypes were IBS-M: 47.6%, IBS-C: 42.8%, IBS-D: 9% andIBS-U: 0.6%. Factors associated to IBS were gender (female 9.5% vs. male 4.7%, p=0.001),unemployed (p=0.001) and high-education level (p=0.05. Overlap of GERD symptomsamong IBS subjects was 48.2%. Conclusions: Prevalence of IBS in Mexico varies from 6.5-8.7%, and is similar among the 8 geographic regions of our country. As in other countriesfemales are more affected and overlap with GERD is common. IBS in Mexico is a frequentdisease independently of the geographic, diet and cultural factors. This study was supportedby research grant of Asofarma Mexico

Su2060

Small Intestinal Microbial Composition Is Different in Veterans With GulfWar IllnessPrashanth Setty, Dionysios A. Antonopoulos, Natalie Mills, Eugene B. Chang, Julie Bard,Jason C. Koval, Henry C. Lin

Three of the top five complaints of patients with Gulf War Illness (GWI) are gastrointestinal,including bloating, abdominal pain and diarrhea (similar to IBS),suggesting the possibilityof an underlying change in gut microbial community. Aim: To test the hypothesis that thesmall intestinal microbiome of patients with GWI may be different from controls. Methods:

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Intestinal biopsy specimens from upper (~100 cm distal to pylorus) and lower (~5 cmproximal to ileocecal valve) sections of the small intestine were obtained from GWI patients(n=17) and control subjects (n=9) during endoscopy. From these specimens DNA was firstisolated, a panel of 16S rRNA specific primers were used to amplify and quantitate fourdifferent bacterial groups (the phyla Bacteroidetes and Firmicutes; and the genera Bifidobact-erium [Actinobacteria] and Desulfovibrio [Proteobacteria]) using quantitative PCR (qPCR).qPCR cycle threshold (Ct) values for these groups in GWI patients and controls werenormalized against actin and then compared in a pair-wise fashion (Lower Ct value = higherbacterial load). In addition, changes in the gut microbial community profile were investigatedby targeting the V4 region (positions 515-806) of the 16S rRNA encoding gene. Triplicatelibraries were prepared and sequenced for each sample as technical replicates on a 151bpx 12bp x 151bp Illumina MiSeq run. Results: Normalized qPCR Ct values of upper GIsection samples revealed a significant increase in the Bacteroidetes (control: 23.66 +/- 1.42,GWI: 21.21 +/- 0.30, p < 0.05) and a significant reduction in Bifidobacterium (control:27.27 +/- 1.69, GWI: 31.02 +/- 0.21, p < 0.01). No significant changes were detected inthe load of Firmicutes and Desulfovibrio. In lower GI section samples, Bacteroidetes weredominant in both control and GWI groups (control: 19.50 +/- 0.62, GWI: 19.60 +/- 0.46)compared to other phyla. MiSeq-derived results also showed that in samples from the upperGI section, the contribution of Bacteroidetes was more pronounced in GWI patients comparedto controls (control: 31.5% GWI: 54.3%). Lower GI section samples were dominated bymembers of the Bacteroidetes in both the control and GWI groups (85.7% and 82.6%respectively) with a minor contribution by members of the Firmicutes (11.9% and 13.8%).Ordinations based on unweighted UniFrac showed a clear delineation between upper andlower GI section samples. Inspection at the genus level of the upper GI section samples fromGulf War patients indicated patient-to-patient variation of dominant genera that supports thedrift observed in the ordinations. Conclusion: The composition of the microbial communityin the small intestine is different in patients with GWI than controls supporting the idea ofshift in the microbiome in GWI.

Su2061

Large Effects of a Low FODMAPs Diet in Patients With Irritable BowelSyndrome: A Systematic Review and Meta-AnalysisMaria Lonshteyn, Apoorva Chandar, Yngve Falck-Ytter

Background: The complaints of patients with irritable bowel syndrome (IBS) revolve aroundabdominal pain, bloating, and dissatisfaction with stool consistency. While pain and inconsis-tent bowel movements can be addressed pharmacologically, limited options exist for effectivereduction of bloating. Building on the findings of observational studies, randomized controltrials (RCTs) have shown benefit in reducing bloating as well as overall gastrointestinalsymptoms from a diet low in fermentable oligosaccharides, disaccharides, monosaccharidesand polyols (FODMAPs). Methods: Electronic databases and conference abstracts weresearched to identify RCTs evaluating the effect of a low FODMAPs diet on overall symptomsin patients with IBS. Meta-analysis was performed using random effects model. Risk of biaswas assessed using the Cochrane risk of bias tool and quality of evidence for outcomesacross studies was determined using GRADE methodology. Results: Out of 187 citations, 4RCTs were identified with a total of 178 participants, each with IBS fulfilling Rome II orIII criteria. The patients were mostly female, aged 21 - 63 and without any significantcomorbidities. Their IBS symptom profile was variable, though patients with constipationpredominant IBS were excluded from one study. In 3 studies, patients were blinded to thediet that they received. Two studies evaluated the effects of a low FODMAPs diet on globalsymptoms, asking patients whether their symptoms were adequately controlled on any givenday; one study assessed the effects of FODMAPs using a Likert scale (0-3) with 0 and 1referring to absent or slight symptoms while 2 and 3 referred to moderate or severe symptoms.The last study evaluated overall gastrointestinal symptoms with a 100 mm visual analoguescale with a reduction >10 mm being clinically important. The duration of the studies rangedfrom 1 - 8 weeks. Pooled results showed that out of 91 patients on an unrestricted diet,75 failed to achieve adequate symptom control while only 21 patients on the low FODMAPsdiet were unsuccessful in adequately controlling their symptoms yielding a relative riskreduction of 69% (95% CI = 55% - 79%; I-squared = 0%). This would translate into 569fewer failures in a thousand to achieve adequate symptom relief (figure). No adverse eventsrelated to the FODMAP diet were reported in the trials. Conclusions: There is moderatequality evidence (GRADE rating) for the use of a low FODMAPs diet in patients with IBSfor reducing functional symptoms such as bloating, flatus and abdominal discomfort. Withsuch a restrictive diet, longer follow up is necessary to monitor adherence, continuedsymptom relief, and potential unanticipated consequences. Currently, given the high rateof response and little apparent harm, a low FODMAPs diet appears effective in the treatmentof IBS.

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