Irritable Bowel Syndrome Group Research Articles

Pain Intensity and Difficulty of Colonoscopy in Patients with Irritable Bowel Syndrome Compared to Patients with Other Diagnoses

Background: Irritable bowel syndrome (IBS) is one of the most common functional disorders of gastrointestinal system. The diagnosis of IBS is made by ROME criteria while excluding other organic causes of symptoms. The presence of alarming sings warrants further evaluation by radiologic or endoscopic studies. It is a common belief among gastroenterologists that colonoscopy in the IBS patients (compared to other patients) is more difficult for the colonoscopists and more painful for the patients. The present study aimed at evaluating the difficulty of colonoscopy, intensity of pain sensation, quality of bowel preparation, and other related findings in the IBS patients compared to non-IBS patients. Methods: This study was conducted during January and May 2016 in a single referral academic colonoscopy center in Shiraz University of Medical Sciences on referring adult patients who were classified into 2 groups, IBS and non-IBS. Duration of procedure, quality of colon preparation, severity of pain, and difficulty of the procedure assessed by Visual Analogue Scale (VAS) were the main assessed parameters. Statistical analysis was performed by SPSS software Version No.16, and independent t test was used to compare the means. Results: In this study, 172 patients (59 males and 113 females) were enrolled and allocated into 2 groups, IBS: 72, non-IBS:100. The mean age in IBS and non-IBS groups was 43.4 and 46.6 years, respectively. Although IBS patients had a more statistically significant pain sensation than non-IBS patients during the procedure (5 vs. 4.4 in VAS, P = 0.03), the quality of colon preparation and difficulty of the procedure revealed no significant differences (7.5 vs. 7.2, P = 0.23; and 4.7 vs. 4.8 in VAS, P = 0.6, respectively). The duration of procedure was significantly lower in the IBS group (13.1 vs. 14.1 minutes, P = 0.006), while the success rate for cecal intubation was similar in both groups (97% vs. 95%, P = 0.7). Conclusions: Our results showed that IBS patients had more pain sensation during the colonoscopy, but the procedure itself was not more difficult in this group of patients. Finally, with a similar success rate the duration of colonoscopy was shorter in IBS patients.

Increased intestinal mucosal leptin levels in patients with diarrhea-predominant irritable bowel syndrome.

AIMTo measure the leptin levels in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and analyze the relationship of leptin with clinical features, visceral sensitivity, mast cells, and nerve fibers.METHODSForty-two patients with IBS-D fulfilling the Rome III criteria and 20 age- and sex-matched healthy controls underwent clinical and psychological evaluations using validated questionnaires (including IBS Symptom Severity Scale, IBS-specific Quality of Life, Hamilton Anxiety Scale, and Hamilton Depression Scale), along with colonoscopy, colonic mucosal biopsy, and visceral sensitivity testing. Serum leptin levels were assayed using enzyme-linked immunosorbent assay. Mucosal leptin expression and localization were evaluated using immunohistochemistry and immunofluorescence. Mucosal leptin mRNA levels were quantified using quantitative real-time reverse transcription polymerase chain reaction. Mast cell counts and activation rates were investigated by toluidine blue staining. Correlation analyses between these parameters were performed.RESULTSThere were no statistically significant differences in age, gender, or body mass index between the IBS-D group and the control group. The median IBS Symptom Severity Scale score in the IBS-D group was 225.0 (range, 100-475). IBS-D patients had significantly increased anxiety [IBS-D: median, 6.5; interquartile range (IQR), 3.3; control: median, 2.0; IQR, 2.0; P < 0.001] and depression (IBS-D: median, 7.0; IQR, 3.0; control: median, 3.0; IQR, 2.0; P < 0.001) scores. IBS-D patients had significantly lower first sensation threshold (IBS-D: median, 50.6; IQR, 25.9; control: median, 80.5; IQR, 18.6; P < 0.001), defecation sensation threshold (IBS-D: median, 91.5; IQR, 29.3; control: median, 155.0; IQR, 21.1; P < 0.001) and maximum tolerable threshold (IBS-D: median, 163.2; IQR, 71.2; control: median, 226.2; IQR, 39.3; P < 0.001). Mucosal leptin expression, as reflected by integrated optical density (IBS-D: median, 4424.71; IQR, 4533.63; control: median, 933.65; IQR, 888.10; P < 0.001), leptin mRNA expression (IBS-D: median, 1.1226; IQR, 1.6351; control: median, 0.8947; IQR, 0.4595; P = 0.009), and mast cell activation rate (IBS-D: median, 71.2%; IQR, 12.9%; control group: median, 59.4%; IQR, 18.88%; P < 0.001) were significantly increased in IBS-D patients. The colocalization of leptin and leptin receptors was observed on mast cells and PGP9.5-positive nerve fibers in the intestinal mucosa. Also, leptin expression was positively correlated with anxiety, depression, and the mast cell activation rate, but negatively correlated with the defecation sensation threshold and the maximum tolerance threshold during visceral sensitivity testing (adjusted P < 0.0038).CONCLUSIONIncreased levels of mucosal leptin may interact with mast cells and the nervous system to contribute to the pathogenesis of IBS-D.

A test of the adaptive network explanation of functional disorders using a machine learning analysis of symptoms

The classification and etiology of functional disorders is controversial. Evidence supports both psychological and biological (disease) models that show, respectively, that functional disorders should be classified as one (bodily distress syndrome) and many (e.g., irritable bowel syndrome (IBS), fibromyalgia syndrome (FMS), and chronic fatigue syndrome (CFS)). Two network models (symptom network and adaptive network) can explain the specificity and covariation of symptomatology, but only the adaptive network model can explain the covariation of the somatic symptoms of functional disorders. The adaptive network model is based on the premise that a network of biological mechanisms has emergent properties and can exhibit adaptation. The purpose of this study was to test the predictions that symptom similarity increases with pathology and that network connection strengths vary with pathology, as this would be consistent with the notion that functional disorder pathology arises from network adaptation. We conducted a symptom internet survey followed by machine learning analysis. Participants were 1751 people reporting IBS, FMS or CFS diagnosis who completed a 61-item symptom questionnaire. Eleven symptom clusters were identified. Differences in symptom clusters between IBS, FMS and CFS groups decreased as overall symptom frequency increased. The strength of outgoing connections between clusters varied as a function of symptom frequency and single versus multiple diagnoses. The findings suggest that the pathology of functional disorders involves an increase in the activity and causal connections between several symptom causing mechanisms. The data provide support for the proposal that the body is capable of complex adaptation and that functional disorders result when rules that normally improve adaptation create maladaptive change.

Modulation of inflammation by toll-like receptor 4/nuclear factor-kappa B in diarrhea-predominant irritable bowel syndrome.

In order to investigate the function of toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signal pathways in the pathogenesis of diarrhea-predominant irritable bowel syndrome (IBS-D), IBS-D animal models were established in wistar rats challenged with acute and chronic stresses (29 days). Wistar rats without stress-challenged were used as controls. IBS-D models were randomly divided into two groups: one was treated with normal saline, another group was treated with TLR4/NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC) (50mg/kg/week) for continuous four times. Our results demonstrate that continuous stresses can induce the characteristic symptoms of IBS-D, including high wet stool rate and intestinal flora imbalance. Further examinations of colon tissues show that the protein expression levels of TLR4 and NF-κB in IBS-D groups are higher than that in control group. The secretory levels of interleukin (IL-8), tumor necrosis factor α (TNFα), and myeloid differentiation factor 88 (MyD88) are significantly increased in IBS-D group. Administration with PDTC effectively downregulates levels of these inflammatory factors. In contrast, interleukin-10 (IL-10) is in an opposite alteration with lower levels in IBS-D groups and the PDTC treatment increases it to the levels as in control group. Moreover, inhibition of the TLR4/NF-κB by PDTC improves the microstructure of intestinal mucosa mainly by increasing the height of villi. Our results suggest that TLR4/NF-κB signal pathway plays an important role in the modulation of inflammatory responses in IBS-D, which might be a therapeutic target for the IBS-D. All of these findings also provide the evidence concerning an inherent linkage between the axis of stress/NF-κB/inflammation and IBS-D.

Anxiety and Depression in Irritable Bowel Syndrome.

Background:Psychological factors have been prominently implicated in the causation as well as maintenance of irritable bowel syndrome (IBS). Studies comparing psychiatric morbidity in IBS with healthy controls have reported contrasting findings. The current study was undertaken to assess the prevalence of anxiety and depression in patients with IBS in comparison to healthy controls and to explore the relationship, if any, of anxiety and depression with various subtypes of IBS.Materials and Methods:Fifty consecutive patients of IBS (diagnosed as per Rome III criteria) between 18 and 65 years of age and fifty age- and sex-matched healthy controls were assessed for the presence of anxiety and depression using Hamilton Rating Scale for Anxiety (HAMA) and Hamilton Rating Scale for Depression (HAMD), respectively.Results:The patient group scored higher than controls (P < 0.001) in both HAMA and HAMD scores. The HAMA scores were significantly higher (P < 0.001) in the severe IBS group compared to those with moderate IBS. HAMA scores predicted 25.6% (R2 = 0.256) of variance in IBS severity scores. However, there was no significant difference between the two groups in terms of HAMD scores.Conclusion:The high prevalence of psychiatric comorbidities such as anxiety and depression in IBS samples in our study provides evidence in favor of proper screening for these disorders in gastrointestinal clinics. Recognition and treatment for these comorbidities can improve the quality of life as well as overall outcomes.

Is Epstein-Barr virus infection associated with the pathogenesis of microscopic colitis?

BackgroundEpstein-Barr virus (EBV) has been associated with inflammation in the colon, particularly in patients with inflammatory bowel disease (IBD). Even if a relevant plasmocytosis, similar to IBD, is present in microscopic colitis (MC), the frequency of EBV infection in this setting is unknown. ObjectivesWe aimed to compare the frequency of colonic EBV infection in patients with MC, ulcerative colitis (UC), and irritable bowel syndrome (IBS). Study designThe frequency of colonic EBV infection in biopsies of 30 patients with MC, 30 patients with UC, and 30 controls with IBS was retrospectively assessed. PCR was performed to detect viral EBV DNA in colonic biopsies. In situ hybridization was also performed to identify and localize EBV-encoded small RNA1 and 2 (EBERs) within cells. ResultsThe presence of EBV DNA was detected in 27 out of 30 MC patients, in 20 out of 30 UC cases, and in none of IBS group. The frequency of EBV DNA in MC was significantly higher compared with that reported in UC (90.0% vs. 66.7%, p=0.03). EBERs+ cells were observed in 18 out of 30 MC patients, in only 3 out of 30 UC patients (60.0% vs. 10.0%, p<0.001), and in none of IBS group. ConclusionsEBV infection is almost always detectable in the colonic mucosa of patients with MC. Further studies are necessary to confirm this association and to clarify the role of EBV in MC and, more generally, in colonic inflammation.

Functional Bowel Disease.

Introduction: Combination of Rome III criteria have a moderate accuracy for diagnosis of Irritable bowel syndrome (IBS). Colonoscopies are performed to rule out other etiologies, and >50% are normal being considered as a “functional disease”. It has been described and impaired intestinal barrier function with mucosal inflammation in the small bowel of this patients, and recent reports evidence a possible organic disease. However, this fact has not been completely evaluated. Aim: to determine utility of Confocal Laser Endomicroscopy (p-CLE) identifying colorectal mucosa micro-inflammation in patients with IBS. Methods: Prospective, controlled, non-randomized and simple blind study (Jan-2016/Mar-2017), including patients with IBS according to Roma III criteria (IBS group), and healthy patients (control group). Exclusion criteria: patients receiving NSAIDs, corticosteroids or antibiotics, heart, kidney, liver or severe metabolic disease, IBD, bacterial overgrowth, gastrointestinal bleeding, history of colitis, colonic obstruction, colectomy, allergy to fluorescein, pregnancy and poor bowel preparation (Boston Scale<6). Both groups underwent colonoscopy using p-CLE with target-biopsy of each colorectal section. Altered crypt architecture, epithelial gaps with fluorescein leaks and dilated and prominent branching vessels were the considered p-CLE criterion for inflammation. Following Geboes Scale, biopsies where evaluated by an only pathologist blinded to endoscopic findings. Overall diagnostic accuracy was defined by sensitivity, specificity, PPV, NPV, observed and inter-rater agreement. Results: A total of 444 biopsies (74 patients) were included (mean age 53.1 [25-90] yo, 64.9% women). Normal colonoscopy was observed in all cases. There were an increased number of inflammatory lesions at p-CLE in IBS group (65.8%) compared with controls (23.4%) (OR 6.28; 4.14 - 9.52; P<0.01) (table 1). Goebes' grade >0 was more frequently in IBS group (60.8 vs. 27.5%; P<0.01). p-CLE for inflammatory findings in IBS, considering target biopsy as gold standard, reached a sensitivity, specificity, PPV, NPV, observed and inter-rater agreement of 86.7, 88.7, 85.9, 89.4, 87.8 and 75.4%. Conclusion: p-CLE proved to be a reliable method for detecting colorectal mucosa micro-inflammation in patients with IBS, showing that patients with IBS have 6 times more prevalence of mucosal colorectal microinflammatory than healthy patients.Inflammatory lesions at p-CLE, n (%)

MicroRNA-29a increased the intestinal membrane permeability of colonic epithelial cells in irritable bowel syndrome rats.

BackgroundThe whole pathogenesis of diarrhea-predominant irritable bowel syndrome(IBS-D) is poorly understood. Our goal was to evaluate the expression change of microRNA-29a(miR-29a) in colonic epithelial cells in IBS rats and clarify the mechanism of miR-29a increasing the intestinal membrane permeability through aquaporins(AQPs).MethodsThe IBS-D rats models were induced by rectal distention pressure combining with extremities constraint. The colonic epithelial cells were divided into four groups. A: normal group. B: IBS-D control group. C: IBS-D +miR-29a NC. D: IBS-D + miR-29a antagomir. The expression of miR-29a, the concentration of the K+ and Lactate Dehydrogenase(LDH) and the expression of AQPs were detected.ResultsThe miR-29a expression increased in IBS-D control group(2.090±0.022) compared with the control group(1.00±0.031) (P<0.001) while it decreased in IBS-D+miR-29a antagomir group(1.403±0.042) compared with IBS-D control group(P<0.001). The K+ decreased in IBS-D control group(1.305±0.289) compared with the control group(2.171±0.204)(P<0.05) while it increased in IBS-D+miR-29a antagomir group(1.813±0.102)(P<0.05) compared with IBS-D control group. The LDH increased in IBS-D control group(4153.440±177.365) compared with the control group(1434.573±96.111)(P<0.001) while it decreased in IBS-D+miR-29a antagomir group(2700.473±275.414) compared with IBS-D control group (P<0.01). The expression of AQP1, AQP3 and AQP8 decreased in IBS-D control group(0.132±0.010,0.110±0.005,0.108±0.007) compared with the control group (P<0.001) while it increased in IBS-D+miR-29a antagomir group(0.197±0.005,0.182±0.011,0.194±0.003) compared with IBS-D control group(P<0.001). The IBS-D+miR-29a negative control(NC) group, a comparison with IBS-D+miR-29a antagomir group, each date showed the similar trend to the IBS-D control group.ConclusionsMiR-29a increased the intestinal membrane permeability of colonic epithelial cells by reducing the AQPs expression in IBS-D rats.

Negative correlation of cortical thickness with the severity and duration of abdominal pain in Asian women with irritable bowel syndrome.

Background & aimsIrritable bowel syndrome (IBS) manifests as chronic abdominal pain. One pathophysiological theory states that the brain–gut axis is responsible for pain control in the intestine. Although several studies have discussed the structural changes in the brain of IBS patients, most of these studies have been conducted in Western populations. Different cultures and sexes experience different pain sensations and have different pain responses. Accordingly, we aimed to identify the specific changes in the cortical thickness of Asian women with IBS and to compare these data to those of non-Asian women with IBS.MethodsThirty Asian female IBS patients (IBS group) and 39 healthy individuals (control group) were included in this study. Brain structural magnetic resonance imaging was performed. We used FreeSurfer to analyze the differences in the cortical thickness and their correlations with patient characteristics.ResultsThe left cuneus, left rostral middle frontal cortex, left supramarginal cortex, right caudal anterior cingulate cortex, and bilateral insula exhibited cortical thinning in the IBS group compared with those in the controls. Furthermore, the brain cortical thickness correlated negatively the severity as well as duration of abdominal pain.ConclusionsSome of our findings differ from those of Western studies. In our study, all of the significant brain regions in the IBS group exhibited cortical thinning compared with those in the controls. The differences in cortical thickness between the IBS patients and controls may provide useful information to facilitate regulating abdominal pain in IBS patients. These findings offer insights into the association of different cultures and sexes with differences in cortical thinning in patients with IBS.

Asymmetries in reciprocal baroreflex mechanisms and chronic pain severity: Focusing on irritable bowel syndrome

Objective measures of pain severity remain ill defined, although its accurate measurement is critical. Reciprocal baroreflex mechanisms of blood pressure (BP) control were found to impact differently on pain regulation, and thus their asymmetry was hypothesized to also connect to chronic pain duration and severity. Seventy-eight female patients with irritable bowel syndrome (IBS) and 27 healthy women were assessed for IBS severity and chronicity, negative affect, and various measures of resting autonomic function including BP, heart rate and its variability (HRV), baroreceptor-sensitivity to activations and inhibitions, gains of brady- and tachy-cardiac baro-responses, gains of BP falls/rises, and BP start points for these spontaneous baroreflexes. IBS directly and indirectly (through increased negative affect) was associated with asymmetry between baroreceptor activations/inhibitions compared to symmetrical baroreflex reciprocity in the healthy women. In the IBS group, independently of specific IBS symptoms, pain chronicity was associated with (i) decreased BP falls coupled with either (a) decreased tachycardia associated with lower disease severity (earlier "pain resilience" mechanism), or (b) decreased bradycardia associated with higher disease severity (later "pain decompensation" mechanism), or (ii) increased BP start point for baroreceptor activations coupled with either (a) BP increase (delayed "pain adaptation" mechanism) or (b) affect-related HRV decrease (delayed "pain aggravation" mechanism). We anticipate the findings to be a starting point for validating these autonomic metrics of pain suffering and pain coping mechanisms in other chronic pain syndromes to suggest them as biomarkers of its severity and duration for profiling and correct management of chronic pain patients.

Differential expression of microRNA related to irritable bowel syndrome in a rabbit model.

This study aimed to evaluate the differential expressions of microRNAs (miRNAs) in white hair black eye (WHBE) rabbits of irritable bowel syndrome (IBS). WHBE and Japanese white (JW) rabbits were divided into the control and IBS groups. The IBS groups were exposed to moist heat, stress and low-dose laxatives. Their intestinal movement rate was measured. Blood samples were taken to detect serum 5-hydroxytryptamine (5-HT) and dopamine levels and colonic tissues were obtained to detect c-Fos expression by immunohistochemistry. Deep sequencing technology was used to obtain miRNA sequences in the intestinal tissues of WHBE and JW control groups. Expressions of 14 miRNAs were measured by real-time polymerase chain reaction in both the control and the IBS model groups. Serum 5-HT and dopamine levels, intestinal movement rate and c-Fos expressions in the WHBE rabbits were significantly increased compared with the control group. MiR-29a-3p, miR-24-3p, miR-221-3p, let-7f-5p, let-7g-5p, let-7i-5p, miR-192-5p, miR-126-3p and miR-130b-3p expressions in WHBE IBS rabbits at day 14 were significantly higher than those in the control group while miR-324-3p and miR-132 were downregulated. MiR-29a-3p, let-7i-5p, miR-192-5p and miR-126-3p were significantly upregulated only in JW IBS rabbits at day 14 and miR-324-3p, miR-223-3p and miR-132 were significantly downregulated in JW IBS group. MiR-24-3p, miR-221-3p, let-7f-5p, miR-126-3p and miR-130b-3p expressions in WHBE IBS rabbits were higher than that in JW IBS rabbits. Twelve miRNAs were differentially expressed in IBS rabbits. Five are specific in WHBE IBS rabbits, suggesting that they play a role in increased sensitivity to IBS.

Visceral sensitivity, gut barrier function and autonomic nerve function in patients with diarrhea-predominant irritable bowel syndrome

To evaluate visceral sensitivity, gut barrier function and autonomic nerve function (ANF) in patients with diarrhea-predominant irritable bowel syndrome (IBS-D), and to explore their roles in IBS-D pathophysiology. Methods: A total of 46 IBS-D patients (IBS-D group) were selected from the Department of Gastroenterology of China-Japan Friendship Hospital from October 2015 to March 2016, and 20 healthy volunteer were served as a control group (HC group). Clinical and psychological symptoms were evaluated by questionnaire, and visceral sensitivity to rectal balloon distention, gut barrier function and autonomic nerve function (ANF) were examined. The difference in the above-mentioned indexes were compared between the 2 groups, and the correlations in the parameters were analyzed in the IBS-D group. Results: The scores of IBS symptom severity scale (IBS-SSS), Hamilton anxiety scale (HAMA), Hamilton depression scale (HAMD) and visceral sensitivity index (VSI) were significantly higher in the IBS-D group than those in the HC group (P<0.01). In the visceral sensitivity test, maximum tolerable threshold in the IBS-D group was significantly decreased compared to that in the HC group (P<0.01); there was no significant difference in first sensation threshold and defecating sensation threshold between the two groups (P>0.05). As gut barrier function markers, the serum diamine oxidase (DAO) and d-lactate were significantly increased in the IBS-D group (P<0.05). In ANF test, the total score and parasympathetic score as well as the proportion of abnormal scores in the IBS-D group were significantly higher than those in the HC group (P<0.05). In IBS-D group, the HAMA, VSI and serum DAO were positively correlated with IBS-SSS (r=0.528, 0.575, 0.507; P<0.01), while the 3 visceral sensitivity thresholds were negatively correlated with IBS-SSS (r= -0.636, -0.476, -0.697; P<0.01); in addition to the IBS-SSS, the HAMA, HAMD, VSI and serum DAO were also significant negatively correlated with the visceral sensitivity thresholds (all P<0.05); no significant correlations were found between the ANF and the other parameters. Conclusion: IBS-D patients show psychological symptoms, visceral hypersensitivity, impaired gut barrier function and abnormal ANF characterized by parasympathetic dysfunction; the former 3 factors are all associated with disease severity, and thus may play vital roles in IBS-D pathophysiology.

Impact of serum-derived bovine immunoglobulin/protein isolate therapy on irritable bowel syndrome and inflammatory bowel disease: a survey of patient perspective.

BackgroundPatients with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) commonly experience diarrhea, abdominal pain, bloating, and urgency. These symptoms significantly compromise the patient’s quality of life (QoL) by limiting participation in normal daily activities and adversely affect work productivity and performance.PurposeThe aim of this study was to understand from the patient’s perspective how oral serum-derived bovine immunoglobulin/protein isolate (SBI) impacts bowel habits, management of condition, and basic QoL.MethodsA 1-page questionnaire was distributed randomly to >14,000 patients who were prescribed SBI (EnteraGam®) for relevant intended uses. The survey was designed to collect data related to the influence of IBS or IBD on daily life activities and the impact of SBI usage on daily stool frequency, management of their condition, and QoL. Patient-reported responses were analyzed using a paired t-test to compare mean change in daily stool output and descriptive statistics for continuous variables.ResultsA total of 1,377 patients returned the surveys. Results from 595 surveys were analyzed with a focus on patients with IBS or IBD who had provided numeric responses regarding daily stool frequency. Respondents with IBS who reported having a normal stool frequency (≤4 stools per day) increased from 35% prior to using SBI to 91% while using SBI. A similar change toward normal stool frequency was reported by IBD respondents. Mean daily stool numbers decreased for respondents in the combined IBS and IBD groups (P=0.0001) from 6.5±4.3 before SBI to 2.6±1.9 following SBI use. The majority of respondents agreed strongly or very strongly that SBI helped them manage their condition (66.9%) and helped them return to the activities they enjoyed (59.1%).ConclusionResults from this patient survey suggest that SBI use can lead to clinically relevant decreases in daily stool frequency in patients with IBS or IBD along with improvements in the overall management of their condition and aspects of QoL.

Effects of microRNA-490-5p on visceral sensitivity in rat with intestinal dysfunction

Objective To investigate the role of microRNA-490-5p (miR-490-5p) in the regulation of visceral sensitivity in rats with intestinal dysfunction. Methods The lentivirus vector system was used to construct the rno-miRNA-490-5p lentivirus expression vector. The rats were divided into normal group, diarrhea-predominant irritable bowel syndrome (IBS-D) group, lentivirus empty vector group and the siRNA silent group and the latter three groups were model groups. The efficiency of siRNA was measured by real-time polymerase chain reaction (PCR). The rats were gavaged with 10% India ink, and then the time of first black stool, water content of feces and threshold of expansion capacity caused abdominal elevation or back arching were calculated. The visceral sensitivity of rats after miRNA-490-5p silenced was evaluated with abdominal withdrawal reflex (AWR) score by stimulating with different intensities of colonic dilatation. The abdominal electrical activity of rats stimulated by colonic distension was measured by BL-420F biological and functional experimental system. The change of the tension of rats isolated colon intestinal stimulated with acetylcholine chloride was also detected by BL-420F biological and functional experimental system. T test was used to compare the differences between the model groups and the normal group. One way analysis of variance was performed for multi-group comparison after miRNA-490-5p interfered. For comparison between two groups among multiple groups, least significant difference (LSD) method was used when the variance was equal, and Games-Howell method was used when the variance was unequal. Results The gastrointestinal propulsion time and the threshold of expansion capacity caused abdominal elevation or back arching of model groups were both lower than those of the normal group ((8.54±4.07) h vs (12.33±2.23) h, (0.56±0.08) mL vs (0.84±0.09) mL), and the differences were statistically significant (t=2.62 and 6.37, both P 0.05). After miRNA-490-5p silenced, gastrointestinal propulsion time of normal group, IBS-D group, lentivirus empty vector group and the siRNA silent group was (11.12±1.01) h, (6.23±3.17) h, (6.09±2.26) h and (12.36±1.97) h, and the differences among four groups were statistically significant (F=10.55, P 0.05). After distension with 1.6 mL sodium chloride solution, the abdominal electrical activity amplitude of silenced group was lower than the other groups, and the differences were statistically significant (F=11.09, P<0.01). After adding 1∶1 000 acetylcholine chloride added, the tension of colon of normal group, IBS-D group, lentivirus empty vector group and the siRNA silent group increased by 0.71±0.21, 0.81±0.06, 0.88±0.21 and 0.43±0.07, however there was no significant difference among the four groups (F=2.57, P=0.100). Conclusions Visceral hypersensitivity existed in rats with intestinal dysfunction. miRNA-490-5p may be involved in the regulation of visceral sensitivity. Key words: Irritable bowel syndrome; Visceral sensitivity; Abdominal electrical activities; Colonic tension; Rat

How painful is this? Idiosyncrasies of attention in irritable Bowel syndrome

IntroductionTheoretical controversy surrounds the issue of the extent to which cognitive processes can be identified which are characteristic of patients with irritable Bowel syndrome (IBS). The issue is important because particular patterns of idiosyncrasies would suggest tailored therapeutic interventions.ObjectivesTo map the processing of pain information in IBS and healthy participants in relation to physical and social threat, using latency as well as frequency metrics.MethodsParticipants (20 with IBS and 33 controls) were tested in an extended exogenous cuing paradigm whose derived measures included assessments of bias, engagement and disengagement. They also completed a battery of health and illness activity tests.ResultsThere was a significant interaction between bias in processing of pain (physical threat) and of neutral stimuli, as shown on Fig. 1. Further significant idiosyncrasies were observed in the relations between measures of attention and levels both of symptoms and of illness behaviour.ConclusionsDetailed evidence was obtained of anomalies in attention in IBS. The results may be interpreted in terms of interactive feedback between pain perception in relation to the gut, pain-specific attentional processes, and health behaviour. It will be discussed how mindfulness based cognitive therapy can be used as an intervention to disrupt this feedback.Disclosure of interestThe authors have not supplied their declaration of competing interest.Fig. 1Attentional bias in IBS and healthy groups with pain and neutral stimuli. Target in the same (valid) or different (invalid) position as the cue, bias = (RT invalid − RT valid).

Water Load Test in Children with Chronic Abdominal Pain or Obesity Compared with Nonobese Controls.

Satiety is the perception of satisfied fullness and represents a summation of neural and hormonal influences. Satiety can be assessed by drink tests, including water load. The objective of our study was to confirm the difference in water load volume between nonobese control children and children with functional dyspepsia (FD), children with irritable bowel syndrome (IBS), and obese children. A total of 158 children ages 6 to 13 years participated in the study. There were 43 children with FD, 25 with IBS, 44 obese children, and 46 nonobese age-matched control children. Subjects drank as much water as possible in 3 minutes or until their stomachs felt full. Children in the FD and IBS groups drank less water than did the nonobese controls; the obese children drank more water than did the nonobese controls. The water load test demonstrated high specificity but poor sensitivity in predicting children with FD. A water load test offers a simple, noninvasive research tool to measure satiety. Children with chronic abdominal pain drank less than nonobese control children; however, the water load test did not discriminate between FD and IBS. Obese children drank more water than the other groups, suggesting the possibility of an underlying abnormality in the perception of satiety.

Blastocystis and irritable bowel syndrome: Frequency and subtypes from Iranian patients

There are inconsistent findings about the role of Blastocystis infection in irritable bowel syndrome (IBS). The present study was aimed to determine the frequency of Blastocystis and their subtypes (ST) in patients with IBS. A total of 122 patients with IBS and 122 healthy individuals referred to the medical laboratory centers in Ahvaz (southwest of Iran) participated in the study. The frequency of Blastocystis was determined. Blastocystis genomic DNA was extracted from positive feces, and PCR was performed using seven primer pairs targeting the SSU rDNA gene. Blastocystis was detected in 19.67% of patients with IBS and 17.2% of individuals without IBS. The difference between two groups was not statistically significant (P=0.3). Among the five subtypes of Blastocystis, ST3 was more common in patients with IBS and control group. However, there were no significant differences between two groups in terms of subtypes of Blastocystis (P=0.6). It seems, the role of Blastocystis in the etiology of IBS should be further investigated. Furthermore, a model of study should be designed to investigate the role of host factors in severity of parasitic disease.

Colonic dysmotility and morphological abnormality frequently detected in Japanese patients with irritable bowel syndrome.

Background/AimsColonoscopy and computed tomography (CT) are used primarily to exclude organic diseases in patients with irritable bowel syndrome (IBS), rather than to assess the pathophysiology of IBS. We aimed to evaluate colonic dysmotility and morphology in Japanese patients with IBS.MethodsOne hundred eighty-four patients with IBS and 49 asymptomatic controls who underwent colonoscopy in combination with CT colonography or barium enema were retrospectively reviewed between 2008 and 2012. Water-aided colonoscopy was performed without sedation by a single endoscopist. The duration and pattern of colonic movement and cecal intubation time were recorded. To assess colonic morphology, barium enema or CT colonography were performed immediately after colonoscopy.ResultsColonic dysmotility was more frequent in the IBS group (28.8% vs. 2.0% in controls, P<0.001), especially in cases of IBS with diarrhea (IBS-D) (IBS with constipation [IBS-C] 28.8% vs. IBS-D 60.0% vs. mixed IBS [IBS-M] 5.1%, P<0.001). Colonic morphological abnormality was more frequent in the IBS group than in the control group (77.7% vs. 24.5%, P<0.001), especially in IBS-M and IBS-C groups (IBS-C 77.5% vs. IBS-D 48.9% vs. IBS-M 100%, P<0.001). Most patients with IBS with colonic dysmotility had experienced stress related to their symptoms. Cecal intubation time was significantly longer in the IBS group than in the control group (12.1±6.9 minutes vs. 4.6±1.9 minutes, P<0.001).ConclusionsUnsedated colonoscopy, combined with radiographic findings, can detect colonic dysmotility and morphological abnormality. Technical difficulties observed during cecal intubation may partially explain the pathophysiology of IBS.

Indications for Small-bowel Capsule Endoscopy in Patients with Chronic Abdominal Pain.

Objective The aim of the present study is to assess the difference in the detection rates of small-bowel lesions in chronic abdominal pain (CAP) patients with irritable bowel syndrome (IBS) and non-IBS. Patients Ninety-nine CAP patients who were scheduled to undergo capsule endoscopy (CE) to investigate their abdominal symptoms were included in this study. Among the subjects, 34 patients fulfilled the Rome III criteria for IBS (IBS group); the remaining 65 patients were categorized as the non-IBS group. CE was performed in both groups and the total enteroscopy achievement rate, small-bowel lesion detection rate, and the presence of small-bowel lesions were evaluated. We also evaluated the patients' blood test results and the rate at which abdominal symptoms improved following internal medication. Results Total enteroscopy was achieved in 62% (21/34) and 86% (56/65) of the IBS and non-IBS patients, respectively. The total enteroscopy achievement rate was significantly higher in non-IBS patients. The small-bowel lesion detection rates were 3% (1/34) and 19% (12/65), respectively, and the detection rate was significantly higher in the non-IBS patients. In the non-IBS patients, mean C-reactive protein (CRP) was significantly higher in the patients with small-bowel lesions. The abdominal symptoms of 12 (92%) of the CAP patients with small-bowel lesions were improved by internal medication. Conclusion CE may be considered for non-IBS CAP patients with high levels of CRP.

Relationship of peripheral blood neutrophil to lymphocyte ratio and irritable bowel syndrome

Background/aim: This study aimed to determine the relationship between the peripheral blood neutrophil to lymphocyte ratio (NLR) and irritable bowel syndrome (IBS). Materials and methods: A total of 107 patients suffering from constipation-predominant IBS, diagnosed in accordance with the ROMA III criteria and having complete blood count tests, were enrolled in this study. All patients underwent total colonoscopy in order to rule out any probable underlying organic colonic pathology. Results: The control group consisted of 106 healthy people with no medical complaints. The peripheral blood NLR was 2.80 ± 2.52 on average in the IBS group. The NLR average was 2.37 ± 1.65 in the control group, and the average NLR ratio in the patient group was statistically significant (P < 0.03) and higher than that of the control group when the patient and the control groups were compared. Conclusion: Peripheral blood NLR as a reliable, precise indicator of inflammation in constipation-predominant IBS patients, detected with a simple complete blood count, was slightly elevated but statistically significant compared to the control group.