Hua Gong

Serum and Colonic Mucosal Immune Markers in Irritable Bowel Syndrome

OBJECTIVES:Low-grade colonic mucosal inflammation has been postulated to have an important role in the pathophysiology of irritable bowel syndrome (IBS). The objectives of this study were (i) to identify serum and tissue-based immunological and neuroendocrine markers associated with mucosal inflammation in male (M) and female (F) patients with non-post-infectious IBS (non-PI-IBS) compared with healthy controls and (ii) to assess possible correlations of such markers with IBS symptoms.METHODS:Sigmoid mucosal biopsies were obtained from 45 Rome II positive IBS patients without a history of PI-IBS (26 F, 35.5% IBS-C, 33.3% IBS-D, 31.1% IBS-A/M) and 41 healthy controls (22 F) in order to measure immunological markers (serum cytokine levels, colonic mucosal mRNA levels of cytokines, mucosal immune cell counts) and neuroendocrine markers associated with mucosal inflammation (corticotropin releasing factor- and neurokinin (NK)-related ligands and receptors, enterochromaffin cells). Symptoms were measured using validated questionnaires.RESULTS:Of all the serum and mucosal cytokines measured, only interleukin-10 (IL-10) mRNA expression showed a group difference, with female, but not male, patients showing lower levels compared with female controls (18.0±2.9 vs. 29.5±4.0, P=0.006). Mucosal mRNA expression of NK-1 receptor was significantly lower (1.15±0.19 vs. 2.66±0.56, P=0.008) in female, but not male, patients compared with healthy controls. No other significant differences were observed.CONCLUSIONS:Immune cell counts and levels of cytokines and neuropeptides that are associated with inflammation were not significantly elevated in the colonic mucosa of non-PI-IBS patients, and did not correlate with symptoms. Thus, these findings do not support that colonic mucosal inflammation consistently has a primary role in these patients. However, the finding of decreased IL-10 mRNA expression may be a possible biomarker of IBS and warrants further investigation.

Tu1392 Psychological Variables Add Incremental Value to Biological Markers in Differentiating IBS From Healthy Volunteers

Background: The development of a diagnostic test for irritable bowel syndrome (IBS) would aid physicians in the clinical management of patients presenting with gastrointestinal complaints without apparent organic cause. While no validated test yet exists there has been promising progress in the area of biological markers (Lembo et et, APT 2009). Given that IBS is thought to be a heterogeneous condition and the biopsychosocial model allows for the possibility of a bidirectional relationship between the central and enteric nervous systems we explored the possibility that psychological variables might provide additional discrimination of IBS from health over and above that provided by a panel of biological markers. Aim: To test the hypothesis that psychological variables provide incremental value in discriminating IBS from health but not IBS subtypes from each other. Method: n=244 individuals recruited from community gastroenterologists and hospital clinics. The sample was comprised of 76 healthy volunteers, 60 IBS-C, 57 IBS-D and 51 IBS-M (mixed). A panel of 34 biological markers was considered (including serum histamine, IL-6, IL-10, TNFalpha, PGE2, VIPr1, tTG) in addition to psychological measures of anxiety and depression (Hospital Anxiety and Depression Scale -HADS), perceived stress and Patient Health Questionnaire (PHQ-15) with items referring to GI complaints removed. Logistic regression was used to create diagnostic models and model performance was assessed through calculation of the area under the receiver-operator characteristic curve (AUC) and sensitivity and specificity with the Rome III criteria as the reference standard. Results: A panel of 34 biomarkers provides useful discrimination of IBS from health with AUC=0.81 and sensitivity 0.81 and specificity 0.64. The addition of four psychological measures increases performance to AUC=0.93 (Fig 1), sensitivity 0.85 and specificity 0.88. Discrimination of IBS-C from IBS-D is increased from AUC 0.92 to 0.94, IBS-C from IBS-M from 0.85 to 0.88 and IBS-D from IBS-M from 0.86 to 0.91. Conclusion: The results supported the hypothesis that psychological characteristics provide independent discrimination of IBS from health. The improvement in overall discriminatory performance appears to result improved specificity with little improvement in sensitivity. The results also supported the hypothesis that psychological characteristics provide little additional value in discriminating IBS subtypes from each other.

S1315 Identification of Novel Metabolites in Serum of Patients With Irritable Bowel Syndrome

Background & Aims: Some reports suggest that probiotics are helpful for treatment of Irritable bowel syndrome (IBS). The aim of this study was to evaluate the effects of probiotic mixture compared with placebo on the symptoms and the compositions of fecal microbiota in patients with diarrhea-dominant IBS (D-IBS). Methods: Forty-seven patients with D-IBS consented by ROME III were randomized in a parallel group, double-blind design to placebo or seven probiotics mixture 7x1011 CFU (Streptococcus thermophous, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium breve) daily for 8 weeks after 1-week run-in period. The primary outcome was the adequate relief (AR) for overall IBS symptoms; secondary outcomes included the individual IBS symptoms, and the IBS quality of life (IBS-QOL). The AR was weekly checked by questionnaire for 10 weeks (8 weeks of treatment phase, 2 weeks of post-treatment phase). The IBS symptom diary based on visual analogue scale (VAS for abdominal pain, abdominal discomfort, diarrhea, urgency, mucus in stool, bloating, passage of gas) and stool parameters (hardness and frequency) were recorded on a daily basis and assessed each week for 11 weeks. IBS-QOL assessment and stool sampling for evaluating the composition of fecal microbiota by denaturing gradient gel electrophoresis (DGGE) were performed at the beginning and at the end of the treatment phase. Results: For all weeks, the proportions of AR was higher in probiotics group than placebo (p<0.05). The proportion of the patients who reported “yes” to adequate relief on half of the weeks (5 weeks) in the treatment trial was significantly higher in probiotics group than placebo (50% vs. 13%, p= 0.01). However, the improvements of the individual symptom scores and stool parameters were not superior in probiotics group. In IBS-QOL, the changing rates of overall scores for probiotics group tended to be higher than those for placebo (21.3±21.6% vs. 9.0±21.5%, p=0.073). The improvements of all 8 domains of IBS-QOL were consistently superior in probiotics group. In the comparison for DGGE profiles of fecal bacteria, there was no difference in the similarities of their bacterial compositions between the two groups. The concordance rates of bacterial compositions from the two time-points were 66.2±13.4% in probiotics and 69.1±11.8% in placebo group (p=0.519). Conclusion: The probiotic mixture is effective in providing adequate relief of overall IBS symptoms, and has a tendency to improve of IBS-QOL in D-IBS. But, the effect of probiotics is not related with the compositional changes of fecal microbiota.

T2072 Colonic Mucosal Inflammation is Unlikely to Play a Primary Role in Irritable Bowel Syndrome

Introduction: An enhanced mucosal immune or inflammatory response has been postulated to play a key role in the pathophysiology of IBS. Previous studies have reported an increase in serum cytokines and colonic mucosal lymphocyte and mast cell counts in IBS patients vs. healthy controls (HCs), but data are inconsistent and limited. Aims: 1) To compare inflammatory markers in the blood and colonic mucosa in IBS and HCs, 2) To determine if these measures are affected by sex, and 3) To explore if these measures are related to IBS symptoms.Methods: Male (M) and female (F) Rome positive IBS patients with stable disease activity and HCs underwent a sigmoidoscopy with colon biopsies (taken at 30 cm from the anal verge). Blood samples were also collected. The following was measured: 1) serum levels of cytokines (IL-1β, IL-6, IL-8, IL-10, and TNF-α), 2) mucosal mRNA levels of the same cytokines, CRF, and CRF1 receptor using real-time PCR, and 3) lymphocyte and mast cell counts per total biopsy area using an automated system. All subjects completed questionnaires assessing GI and non-GI symptoms. Results: 45 IBS patients (26F, 19M) and 41 agematched HCs (22F, 19M) were studied. IBS subtypes were 34% IBS-C, 34% IBS-D, and 32% IBS-M/A. None of the IBS patients had documented post-infectious IBS. Overall, there were no statistically significant differences in any of the measured inflammatory markers between IBS patients and HCs. However, group differences were seen amongst female subjects. Compared to healthy women, female IBS had a small but significant mean increase in serum level of the pro-inflammatory cytokine TNF-α (4.4±0.08 vs. 4.1±0.06 pg/ml, p= 0.046). They also had lower mucosal mRNA levels of the anti-inflammatory cytokine IL-10 compared to HCs (4.9±0.1 vs. 5.5±0.2, p=0.02). However, neither finding maintained statistical significance when corrected for multiple comparisons. Serum cytokine levels did not correlate with their respective mucosal cytokine mRNA levels (p=NS). There were no significant differences in CRF colonic mucosal expression or cell counts between IBS and controls. Serum IL-10 levels (r=-0.44, p = 0.006) and colonic mucosal CRF expression (r=0.45, p=0.003) negatively correlated with current symptom ratings. Conclusion: Taken together, the lack of strong and significant differences in mucosal and serum immune markers between IBS andHCs argues against the presence of a predominant proinflammatory response within the colonic mucosa in IBS. Further studies are needed to determine if an immune disturbance plays a more significant role in women with IBS, and if immune markers are associated with symptom flares in IBS.