Irritable Bowel Syndrome Group Research Articles

Sleep Disturbances Are Commonly Reported Among Patients Presenting to a Gastroenterology Clinic.

Poor sleep quality is common among patients with gastrointestinal (GI) disorders. However, few studies have assessed the presence of insomnia or reported circadian preferences and none have directly compared sleep between common GI conditions. To compare clinical sleep characteristics in patients presenting to a tertiary care GI clinic for irritable bowel syndrome (IBS), functional dyspepsia (FD), inflammatory bowel disease (IBD), gastroesophageal reflux disease (GERD), and celiac disease (CD). Validated sleep measures were administered to consecutive patients if they were diagnosed with IBS, IBD in clinical remission, CD, FD, or GERD. Healthy Controls (HCs) with no reported GI diagnoses or symptoms were also recruited. A total of 212 eligible respondents completed this survey, 161 GI clinic patients (IBS (n = 48), GERD (n = 29), IBD in clinical remission (n = 44), CD (n = 40)), and 41 HCs. Only, 10 respondents had a diagnosis of FD, and these were excluded. The IBS group had the highest frequency of poor sleep (72%) followed by CD (61%), GERD (60%), IBD (54%), and HC (39%). IBS patients also had the highest frequency of clinical insomnia (51%), followed by GERD (37%), CD (35%), IBD (27%), and HC (18%). 40% of IBS patients reported taking sleep medications at least once per week, compared to 32% of GERD, 23% IBD, 13% CD, and 15% HC. Patients presenting to a tertiary care GI clinic report poorer sleep than healthy controls. In general, patients with IBS report the highest rates of sleep difficulties compared to patients with other diagnoses.

Complex Neurobehavioral Testing of a Rat Model of the Irritable Bowel Syndrome

In albino Wistar rats, the irritable bowel syndrome (IBS) was induced by chronic restraint stress (restriction of the animals in plastic containers, 6 h per day during 7 days). In the Y-like maze, IBS rats demonstrated smaller numbers of spontaneous alternations (indices of immediate spatial memory; P < 0.05) than control animals. In the elevated plus maze, IBS rats showed a significantly reduced time spent in the open arms (P < 0.03) compared to the controls, suggesting anxiety-like effects. Moreover, episodes of stretching in this maze were more numerous in the IBS group (P < 0.05), also suggesting anxiogenic effects. Some depression-like behavior of IBS rats was observed in the forced swimming test, as was demonstrated by a significantly shorter mobility time, as compared to the control group (P < 0.05). In the radial 8-arm maze, however, chronic stress-induced IBS did not significantly affect the number of reference memory errors and time necessary for completing the task. Still, some working memory deficit was observed in the IBS group in this test, as the number of the respective errors was significantly greater (P < 0.05) in such rats vs. controls within some time intervals. In the open field test, suppression of locomotor activity (reduced number of square crossings), significantly increased number of rearings (suggesting higher anxiety), and altered fecal elimination in the IBS group were obvious (P < 0.05). Also, an increased time of grooming was observed in IBS rats in the above test (characterizing a higher anxiety level in the stress-exposed IBS group). When zoosocial behavior was tested in a three-chambered apparatus (10-min-long period of testing), rats of the IBS group spent significantly more time in the empty compartment (without a stranger rat) and less time in the compartment with a conspecific of the same age and weight (P < 0.01), which indicates decreased social motivation in the IBS group. Our results suggest that the aforementioned chronic stress-induced IBS model results in increased anxiety, depression, and suppressed social behavior. The IBS affects immediate and working memory (with nearly no effect, however, on reference memory).

Patients' perspectives on GP interactions after cognitive behavioural therapy for refractory IBS: a qualitative study in UK primary and secondary care.

BackgroundPrevious studies have identified issues with the doctor–patient relationship in irritable bowel syndrome (IBS) that negatively impact symptom management. Despite this, little research has explored interactions between GPs and patients with refractory IBS. National guidelines suggest cognitive behavioural therapy (CBT) as a treatment option for refractory symptoms.AimTo explore perceptions of interactions with GPs in individuals with refractory IBS after receiving CBT for IBS or treatment as usual (TAU).Design and settingThis qualitative study was embedded within a trial assessing CBT in refractory IBS. Fifty-two participants took part in semi-structured interviews post-treatment in UK primary and secondary care.MethodInductive and/or data-driven thematic analysis was conducted to identify themes in the interview data.ResultsTwo key themes were identified: perceived paucity of GPs’ IBS knowledge and lack of empathy from GPs, but with acknowledgement that this has improved in recent years. These perceptions were described through three main stages of care: reaching a ‘last-resort diagnosis’; searching for the right treatment through a trial-and-error process, which lacked patient involvement; and unsatisfactory long-term management. Only CBT participants reported a shared responsibility with their doctors concerning symptom management and an intention to reduce health-seeking behaviour.ConclusionIn this refractory IBS group, specific doctor–patient communication issues were identified. Increased explanation of the process of reaching a positive diagnosis, more involvement of patients in treatment options (including a realistic appraisal of potential benefit), and further validation of symptoms could help. This study supports a role for CBT-based IBS self-management programmes to help address these areas and a suggestion that earlier access to these programmes may be beneficial.

Microstructural White Matter Abnormalities in the Dorsal Cingulum of Adolescents with IBS.

Alterations in fractional anisotropy (FA) have been considered to reflect microstructural white matter (WM) changes in disease conditions; however, no study to date has examined WM changes using diffusion tensor imaging (DTI) in adolescents with irritable bowel syndrome (IBS). The objective of the present study was two-fold: (1) to determine whether differences in FA, and other non-FA metrics, were present in adolescents with IBS compared to healthy controls using whole-brain, region of interest (ROI)-restricted tract-based spatial statistics (TBSS) and canonical ROI DTI analyses for the cingulum bundle, and (2) to determine whether these metrics were related to clinical measures of disease duration and pain intensity in the IBS group. A total of 16 adolescents with a Rome III diagnosis of IBS (females = 12; mean age = 16.29, age range: 11.96–18.5 years) and 16 age- and gender-matched healthy controls (females = 12; mean age = 16.24; age range: 11.71–20.32 years) participated in this study. Diffusion-weighted images were acquired using a Siemens 3-T Trio Tim Syngo MRI scanner with a 32-channel head coil. The ROI-restricted TBSS and canonical ROI-based DTI analyses revealed that adolescents with IBS showed decreased FA in the right dorsal cingulum bundle compared to controls. No relationship between FA and disease severity measures was found. Microstructural WM alterations in the right dorsal cingulum bundle in adolescents with IBS may reflect a premorbid brain state or the emergence of a disease-driven process that results from complex changes in pain- and affect-related processing via spinothalamic and corticolimbic pathways.

Does the number of mucosal immune cells differ in irritable bowel syndrome and its subtypes?

Recently, mucosal inflammation has been proposed to be one of the mechanisms underlying the pathophysiology of irritable bowel syndrome (IBS); however, there are controversial results regarding this hypotheses. Our aim was to evaluate immune cell infiltration in rectal and ileal biopsy specimens of patients with IBS and to compare it with those of healthy controls. In total, 36 patients with IBS (15 with diarrhea and 21 with constipation) and 16 healthy volunteers were enrolled. Ileocolonoscopy and ileal/rectal biopsies were performed. Rectal and terminal ileal biopsy specimens were evaluated for mucosal immune cell infiltration using immunohistochemical analysis. Serotonin positivity as well as counts of intraepithelial lymphocytes (IEL) and CD4+, CD8+, CD20+, and CD3+ cells were determined by a single pathologist who is an expert in the gastrointestinal system. CD3+ and CD4+ cell counts in rectal and terminal ileal biopsy specimens were lower in the IBS group than in the controls. Conversely, there was no statistically significant difference between the IBS and control groups in terms of serotonin positivity as well as counts of IEL and CD20+ and CD8+ cells. Comparison between the IBS subgroups revealed a higher number of IEL in rectal biopsy specimens of the diarrhea dominant group. In the IBS subgroups, immune cell counts in terminal ileal and rectal biopsy specimens showed a positive correlation. IBS and its subgroups showed lower immune cell counts than the controls in our study. These results indicate that there is no significant mucosal inflammation in homogeneous groups of patients with IBS. Rectal biopsies may be sufficient for the evaluation of inflammation in IBS.

How the Change in IBS Criteria From Rome III to Rome IV Impacts on Clinical Characteristics and Key Pathophysiological Factors.

The diagnostic criteria for irritable bowel syndrome (IBS) have recently been updated from Rome III to Rome IV. Whereas in Rome III a diagnosis of IBS entailed chronic abdominal pain or discomfort at least 3 days per month, in Rome IV the term discomfort has been removed and the frequency of abdominal pain increased to at least 1 day per week. We examined how this change in IBS criteria impacts on clinical characteristics and pathophysiological factors. A total of 542 Swedish subjects with Rome III IBS completed a baseline questionnaire enquiring for the number of abdominal pain days in the last 10 days; this was subsequently used as a surrogate marker to identify Rome IV IBS, in that (a) those with 0 or 1 day of pain were classed as Rome IV-negative, and (b) those with ≥2 days of pain were classed as Rome IV-positive. Comparisons were made between Rome IV-positive and -negative IBS groups for demographics, IBS subtype, gastrointestinal and psychological symptoms, somatisation, fatigue, disease-specific quality of life, rectal sensitivity, and oro-anal transit time. Overall, 85% of Rome III IBS patients fulfilled the Rome IV criteria for IBS, but 15% did not. Rome IV-positive subjects were significantly more likely to be female, have poorer quality of life, greater pain severity, bloating, somatisation, fatigue, and rectal sensitivity than Rome IV-negative subjects. There were no differences in severity of anxiety or depression, IBS subtypes, bowel habit dissatisfaction, or oro-anal transit time. Finally, increasing number of pain days correlated positively with symptoms and visceral hypersensitivity. Most Rome III-positive IBS patients seeking healthcare fulfil the Rome IV IBS criteria. They constitute a more severe group than those who lose their IBS diagnosis.

Parasutterella, in association with irritable bowel syndrome and intestinal chronic inflammation.

Irritable bowel syndrome (IBS) is a highly prevalent chronic functional gastrointestinal disorder. Recent studies have showed increasing important role of gut microbiota in the pathophysiological changes of IBS. Our study aims to elaborate the association between intestinal flora with the genesis and the development of IBS. Illumina high-throughput sequencing technology was applied to investigate microbial communities of IBS patients and healthy donors. Stool specimens from the IBS-D patients were equally premixed and implanted into germ free C57B/6 mice to construct IBS animal model, and the normal group was also transplanted with normal premixed feces. The post-transplant defecation and intra-epithelial lymphocyte counts were evaluated. Microbial communities were also checked by the illumina high-throughput sequencing technology. Fifteen genuses significantly different were found expressed in the gut flora of IBS patients, and six genuses showed significantly different abundances between the stool specimens of mice of IBS group and normal group. Among these differences, Parasutterella expression was remarkably different in both screening and validation experiments and also related to chronic intestinal inflammation; therefore, Parasutterella expression is considered in association with the development and progression of IBS. Parasutterella may be related with the genesis and development of IBS and also associated with chronic intestinal inflammation in IBS patients.

Characteristics of the bacterial microbiome in association with common intestinal parasites in irritable bowel syndrome.

ObjectiveA low prevalence of intestinal parasites has been identified in individuals with irritable bowel syndrome (IBS), but potential associations with alterations in the bacterial microbiome remain largely unexplored. We aimed to investigate the relationship between parasites and bacteria in individuals with IBS in order to identify potential trans-kingdom microbial characteristics.DesignStool samples were collected from the Danish background population classified into IBS (n = 119), unspecific gastrointestinal (GI) symptoms (n = 114), and asymptomatic controls (n = 186) based on the Rome III criteria for IBS. Bacterial (16S) and eukaryotic (18S) ribosomal DNA was sequenced, and 18S data were merged with data from conventional parasite laboratory tests. The bacterial microbiome was analyzed according to symptom group and parasite colonization status.ResultsBacterial richness and diversity were similar for IBS and controls but higher in those with unspecific GI symptoms. A higher abundance of Bacteroides and a lower abundance of Faecalibacterium were detected in individuals with IBS and unspecific GI symptoms compared with controls. Principal component analyses indicated differences in bacterial composition related to parasite colonization rather than symptom group. Parasites were detected at the lowest frequency in the IBS group (39%) and in samples dominated by Bacteroides. Higher bacterial richness and diversity were found in parasite-positive samples from controls and those with unspecific GI symptoms but not in individuals with IBS.ConclusionParasite colonization, rather than bacterial composition, differed between individuals with IBS and healthy controls. Parasite colonization was associated to a rich and diverse bacterial microbiome; however, this association was altered in IBS.

Quantitation of Colonic Cells as Severity Markers in Patients with Irritable Bowel Syndrome

Background: Irritable bowel syndrome (IBS) is the most common gastrointestinal syndrome. Routine histopathology and immunohistochemistry (IHC) evaluations have shown an increase in the number of different inflammatory cells in the colon of IBS patients. In this study, we have compared the number of intraepithelial lymphocytes (IELs), eosinophils, mast cells and CD3+ T cells, in IBS patients and normal subjects. Materials and Methods: In 2016, seventy-nine patients with IBS and seventy-nine healthy subjects who underwent colonoscopy for other non-specific causes and with no pathologic findings, were enrolled in this cross-sectional study. Biopsy specimens obtained from the colon were stained, using IHC methods to determine the number of IELs, eosinophils, mast cells and CD3+ T cells. Quantitative and qualitative variables were compared between the two groups, using a Chi-square test and Student’s t-test. Results: Seventy-nine patients with IBS, 79.7% females with a mean age of 42.5±14.6 years, were recruited, as the case group, and seventy-nine individuals, 51.9% females with a mean age of 39.7±18.9 years, were enrolled as controls. The average number of IELs per high power fields (hpf) was found to be higher in the IBS group, and this difference was statistically significant (32.8±11.8 vs. 28.6±12.9; P=0.034). Also, the mean count/hpf of CD3+ T lymphocytes (23.1±7.9 vs. 20.2±8.1; P=0.024) and mast cells (7.6±3.1 vs. 6.6±3.0; P=0.041) were significantly higher in the IBS group, compared to the control group. The number of eosinophils was higher in the IBS group, but the differences were not statistically significant (P=0.066). Conclusion: According to the results, we suggest that analysis of immune cells and IELs in intestinal biopsies might be an appropriate method for diagnosis of IBS. [GMJ.2018;7:e1063]

Quantitation of Colonic Cells as Severity Markers in Patients with Irritable Bowel Syndrome

Background: Irritable bowel syndrome (IBS) is the most common gastrointestinal syndrome. Routine histopathology and immunohistochemistry (IHC) evaluations have shown an increase in the number of different inflammatory cells in the colon of IBS patients. In this study, we have compared the number of intraepithelial lymphocytes (IELs), eosinophils, mast cells and CD3+ T cells, in IBS patients and normal subjects. Materials and Methods: In 2016, seventy-nine patients with IBS and seventy-nine healthy subjects who underwent colonoscopy for other non-specific causes and with no pathologic findings, were enrolled in this cross-sectional study. Biopsy specimens obtained from the colon were stained, using IHC methods to determine the number of IELs, eosinophils, mast cells and CD3+ T cells. Quantitative and qualitative variables were compared between the two groups, using a Chi-square test and Student’s t-test. Results: Seventy-nine patients with IBS, 79.7% females with a mean age of 42.5±14.6 years, were recruited, as the case group, and seventy-nine individuals, 51.9% females with a mean age of 39.7±18.9 years, were enrolled as controls. The average number of IELs per high power fields (hpf) was found to be higher in the IBS group, and this difference was statistically significant (32.8±11.8 vs. 28.6±12.9; P=0.034). Also, the mean count/hpf of CD3+ T lymphocytes (23.1±7.9 vs. 20.2±8.1; P=0.024) and mast cells (7.6±3.1 vs. 6.6±3.0; P=0.041) were significantly higher in the IBS group, compared to the control group. The number of eosinophils was higher in the IBS group, but the differences were not statistically significant (P=0.066). Conclusion: According to the results, we suggest that analysis of immune cells and IELs in intestinal biopsies might be an appropriate method for diagnosis of IBS. [GMJ.2018;7:e1063]

Quantitation of Colonic Cells as Severity Markers in Patients with Irritable Bowel Syndrome.

Background: Irritable bowel syndrome (IBS) is the most common gastrointestinal syndrome. Routine histopathology and immunohistochemistry (IHC) evaluations have shown an increase in the number of different inflammatory cells in the colon of IBS patients. In this study, we have compared the number of intraepithelial lymphocytes (IELs), eosinophils, mast cells and CD3+ T cells, in IBS patients and normal subjects. Materials and Methods: In 2016, seventynine patients with IBS and seventy-nine healthy subjects who underwent colonoscopy for other non-specific causes and with no pathologic findings, were enrolled in this cross-sectional study. Biopsy specimens obtained from the colon were stained, using IHC methods to determine the number of IELs, eosinophils, mast cells and CD3+ T cells. Quantitative and qualitative variables were compared between the two groups, using a Chi-square test and Student’s t-test. Results: Seventy-nine patients with IBS, 79.7% females with a mean age of 42.5±14.6 years, were recruited, as the case group, and seventy-nine individuals, 51.9% females with a mean age of 39.7±18.9 years, were enrolled as controls. The average number of IELs per high power fields (hpf) was found to be higher in the IBS group, and this difference was statistically significant (32.8±11.8 vs. 28.6±12.9; P=0.034). Also, the mean count/hpf of CD3+ T lymphocytes (23.1±7.9 vs. 20.2±8.1; P=0.024) and mast cells (7.6±3.1 vs. 6.6±3.0; P=0.041) were significantly higher in the IBS group, compared to the control group. The number of eosinophils was higher in the IBS group, but the differences were not statistically significant (P=0.066). Conclusion: According to the results, we suggest that analysis of immune cells and IELs in intestinal biopsies might be an appropriate method for diagnosis of IBS.

Functional Dyspepsia and Severity of Psychologic Symptoms Associate With Postprandial Symptoms in Patients With Irritable Bowel Syndrome

Patients with irritable bowel syndrome (IBS) have an increased response of postprandial symptoms to a combined lactulose nutrient challenge test, compared with healthy volunteers. We investigated the associations among comorbid functional dyspepsia (FD), severity of psychologic symptoms, and breath test results in response to this test. We performed a prospective study of 205 patients with IBS (Rome III criteria), 94 of whom also had FD (IBS-FD), and 83 healthy volunteers in Sweden from 2008 through 2015. All participants completed a breath hydrogen test after a 400-mL liquid meal with 25 g lactulose. Gastrointestinal (GI) symptom severity was assessed using a graded scale and digestive comfort was recorded before the meal and every 15 minutes until 240 minutes after the meal. GI symptom scores over time were compared between groups using linear mixed models with anxiety, depression, and somatization as covariates. Average levels of all GI symptoms varied over time among all groups (P < .0001). Patients with IBS-FD had higher levels of bloating (P= .004), abdominal pain (P= .005), and lower levels of digestive comfort (P < .01) than patients with only IBS. We observed a difference in increase in abdominal pain from baseline between IBS-FD and IBS groups (P= .013). Anxiety levels were associated with levels of all symptoms (all P < .025) except abdominal pain, which was associated with somatization severity (P < .0001). Furthermore, anxiety levels associated with level of exhaled hydrogen (P= .0042). In a prospective study of patients with IBS, we found those with FD to have increased GI symptoms before and after a liquid meal with lactulose. Anxiety and somatization have an independent additional effect. The presence of comorbid FD and levels of psychologic symptoms affect reports of food-related symptoms in patients with IBS. ClinicalTrial.gov no: NCT01252550.

Mean Platelet volume to platelet and red cell distribution width to platelet ratios in Irritable Bowel Syndrome

Aim: Irritable Bowel syndrome (IBS) is a common gastrointestinal disease worldwide with a broad spectrum of symptoms. In present retrospective study, we aimed to compare mean platelet volume to platelet ratio (MPR) and red cell distribution width to platelet ratio (RPR) values of IBS patients to those of healthy subjects. Methods: Patients whom followed up in internal medicine clinic of our institution between 2014 January to 2018 January were enrolled to the study. IBS subjects divided into constipation dominant or diarrhea dominant IBS groups. Healthy individuals visited our outpatient clinics for a check-up were enrolled as control group. Results: Median MPR of the constipation IBS, diarrhea IS and control groups were 0,034 (0,02-0,06), 0,034 (0,02-0,06), and 0,028 (0,01-0,05), respectively. The difference between groups was statistically significant (p=0.004). Conclusion: We think that elevated MPR in a patient with typical symptoms of IBS could be helpful in the diagnosis of the disease. Therefore, we suggest automatic calculation of MPR in hemogram assays.

Exploring the link between Irritable Bowel Syndrome and the microbiome

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal (GI) disorder featuring chronic or recurrent abdominal discomfort, usually with changes in GI habit. However, the mechanisms responsible for IBS are poorly understood. Although alterations in the GI microbiome has been implicated in IBS, there is a lack of consensus on what the exact role of the microbiome is, and how it changes, in IBS. To gain a better understanding of the link between the microbiome and IBS, we undertook shotgun metagenomic sequencing of faecal samples from a case‐control study. The overall aim of the study was to identify microbial and metabolomic factors that provide mechanistic insights into functional GI disorders and increase the predictability of phenotypes for use in nutrition intervention studies. Faecal samples from 112 individuals with functional GI symptoms (cases) or those that were asymptomatic (controls) were shotgun sequenced using the Illumina NextSeq platform. Taxonomic classifications were determined using Metaxa2 and the SILVA 128 database. Gene functions were assigned with the MG‐RAST pipeline. Bacterial genera that discriminated case‐controls from IBS groups included Faecalibacterium, Blautia, Roseburia, Bilophila, and Streptococcus, which were relatively more abundant in certain IBS subtypes. For example, Faecalibacterium was relatively more abundant in individuals presenting with constipation associated IBS (IBS‐C; P&lt;0.001), while Blautia was more prominent in those with the diarrhea form of IBS (IBS‐D; P=0.015). Gene functions that best separated groups included those related to carbohydrate metabolism (higher in IBS compared to case‐controls), protein metabolism, and virulence factors. Our results suggest that carbohydrate fermentation by the microbiome may be an important factor in IBS. This work shows that efforts to understand the role of the microbiome in IBS need to include consideration of microbial function rather than just microbial composition.Support or Funding InformationFunded by the Ministry of Business, Innovation and Employment, New ZealandThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The relationship between lower urinary tract symptoms and irritable bowel syndrome: a meta-analysis of cross-sectional studies.

While several epidemiologic studies have investigated the relationship between lower urinary tract symptoms (LUTS) and irritable bowel syndrome (IBS), it remains unclear. To investigate the relationship between IBS and LUTS, a systematic review and meta-analysis of cross-sectional studies was carried out. Online databases were searched up to December 1st, 2017 for cross-sectional studies that evaluated the association between IBS and the risk of LUTS. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. In all, 9 articles that contained 19907 participants and 2620 cases of LUTS were included in this meta-analysis. Compared with the non-IBS group, the IBS group had a higher risk of LUTS (total OR=2.11, 95% CI: 1.91-2.33, P<0.00001). Patients with IBS were more likely to have urine storage symptoms (total OR=1.80, 95% CI: 1.34-2.42, P<0.0001). Subgroup analysis by gender showed that the IBS group had a higher risk of LUTS in both men (total OR=2.17, 95% CI: 1.82-2.58, P<0.00001) and women (total OR=1.85, 95% CI: 1.57-2.17, P<0.00001). Our meta-analysis provides evidence that IBS is associated with an increased risk of LUTS in both men and women.

Altered attentional control linked to catastrophizing in patients with irritable bowel syndrome.

Our study aimed to investigate differences in attentional control between patients with irritable bowel syndrome (IBS) and healthy participants and to examine the link between attentional control and IBS catastrophizing. Previous research has shown that patients with chronic functional illnesses have lower levels of attentional control. However, no previous study has found altered attentional control in patients with IBS or directly investigated the link between attentional control and catastrophizing. We also aimed to establish whether anxiety is associated with attentional functions in patients with IBS. In this cross-sectional study, we compared 41 IBS patients with 39 healthy-matched control participants on attentional functions using an attention network task. IBS catastrophizing (Gastrointestinal Cognitions), IBS symptom severity (GSRS-IBS), Depression, Anxiety, and Stress (DASS-21), and Visceral Anxiety Sensitivity were assessed using self-report measures. Patients with IBS had lower attentional control compared to healthy participants, t (78)=-2.75, p=.007, d=.62. Groups did not differ in alerting or orienting attention. IBS patients with lower attentional control scored higher on IBS catastrophizing than those with higher attention control, t (38.59)=2.19, p=.032, d=.66. Anxiety was related to orienting attention in the IBS group (ρ=.38, p=.015). Patients with IBS displayed reduced attentional control. Crucially, those patients with lower attentional control also had more catastrophizing thoughts than patients with better attentional control. These findings suggest that improving attentional control could be a valid target for psychological interventions for IBS. Statement of contribution What is already known on this subject? It has been hypothesised that psychological processes play a role in the maintenance of irritable bowel syndrome (IBS), and altered levels of attentional control have been found in patients with other functional illnesses but not yet in patients with IBS. Pain catastrophizing, a maladaptive thinking pattern, has been linked with IBS symptom severity, and previous research has shown an association between attentional control and intrusive thoughts. Whether there is an association between catastrophizing thoughts and attentional control in patients with IBS is unknown. What does this study add? Patients with irritable bowel syndrome show reduced levels of attentional control. IBS patients with lower levels of attentional control have more catastrophizing thoughts. Therapies emphasizing attentional control training may help reduce catastrophizing.

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

[This corrects the article DOI: 10.18632/oncotarget.20687.].

Gas chromatography/mass spectrometry based metabolomic study in a murine model of irritable bowel syndrome.

AIMTo study the role of microbial metabolites in the modulation of biochemical and physiological processes in irritable bowel syndrome (IBS).METHODSIn the current study, using a metabolomic approach, we analyzed the key metabolites differentially excreted in the feces of control mice and mice with IBS, with or without Clostridium butyricum (C. butyricum) treatment. C57BL/6 mice were divided into control, IBS, and IBS + C. butyricum groups. In the IBS and IBS + C. butyricum groups, the mice were subjected to water avoidance stress (WAS) for 1 h/d for ten days. Gas chromatography/mass spectrometry (GC-MS) together with multivariate analysis was employed to compare the fecal samples between groups.RESULTSWAS exposure established an appropriate model of IBS in mice, with symptoms of visceral hyperalgesia and diarrhea. The differences in the metabolite profiles between the control group and IBS group significantly changed with the progression of IBS (days 0, 5, 10, and 17). A total of 14 differentially excreted metabolites were identified between the control and IBS groups, and phenylethylamine was a major metabolite induced by stress. In addition, phenylalanine metabolism was found to be the most relevant metabolic pathway. Between the IBS group and IBS + C. butyricum group, 10 differentially excreted metabolites were identified. Among these, pantothenate and coenzyme A (CoA) biosynthesis metabolites, as well as steroid hormone biosynthesis metabolites were identified as significantly relevant metabolic pathways.CONCLUSIONThe metabolic profile of IBS mice is significantly altered compared to control mice. Supplementation with C. butyricum to IBS mice may provide a considerable benefit by modulating host metabolism.

Inhibitory effects of patchouli alcohol on stress-induced diarrhea-predominant irritable bowel syndrome.

AIMTo elucidate the mechanism of patchouli alcohol (PA) in treatment of rat models of diarrhea-predominant irritable bowel syndrome (IBS-D).METHODSWe studied the effects of PA on colonic spontaneous motility using its cumulative log concentration (3 × 10−7 mol/L to 1 × 10−4 mol/L). We then determined the responses of the proximal and distal colon segments of rats to the following stimuli: (1) carbachol (1 × 10−9 mol/L to 1 × 10−5 mol/L); (2) neurotransmitter antagonists including Nω-nitro-L-arginine methyl ester hydrochloride (10 μmol/L) and (1R*, 2S*)-4-[2-Iodo-6-(methylamino)-9H-purin-9-yl]-2-(phosphonooxy)bicyclo[3.1.0]hexane-1-methanol dihydrogen phosphate ester tetraammonium salt (1 μmol/L); (3) agonist α,β-methyleneadenosine 5′-triphosphate trisodium salt (100 μmol/L); and (4) single KCl doses (120 mmol/L). The effects of blockers against antagonist responses were also assessed by pretreatment with PA (100 μmol/L) for 1 min. Electrical-field stimulation (40 V, 2-30 Hz, 0.5 ms pulse duration, and 10 s) was performed to observe nonadrenergic, noncholinergic neurotransmitter release in IBS-D rat colon. The ATP level of Kreb’s solution was also determined.RESULTSPA exerted a concentration-dependent inhibitory effect on the spontaneous contraction of the colonic longitudinal smooth muscle, and the half maximal effective concentration (EC50) was 41.9 μmol/L. In comparison with the KCl-treated IBS-D group, the contractile response (mg contractions) in the PA + KCl-treated IBS-D group (11.87 ± 3.34) was significantly decreased in the peak tension (P < 0.01). Compared with CCh-treated IBS-D rat colon, the cholinergic contractile response of IBS-D rat colonic smooth muscle (EC50 = 0.94 μmol/L) was significantly decreased by PA (EC50 = 37.43 μmol/L) (P < 0.05). Lack of nitrergic neurotransmitter release in stress-induced IBS-D rats showed contraction effects on colonic smooth muscle. Pretreatment with PA resulted in inhibitory effect on L-NAME-induced (10 μmol/L) contraction (P < 0.05). ATP might not be the main neurotransmitter involved in inhibitory effects of PA in the colonic relaxation of stress-induced IBS-D rats.CONCLUSIONPA application may serve as a new therapeutic approach for IBS-D.

Clostridium butyricum regulates visceral hypersensitivity of irritable bowel syndrome by inhibiting colonic mucous low grade inflammation through its action on NLRP6.

Visceral hypersensitivity induced by stress is quite common in irritable bowel syndrome (IBS) patients. Probiotics play an important role in reducing visceral hypersensitivity in IBS patients. However, the mechanism has not been clearly elucidated. In this study, we investigated the role of nod-like receptor pyrin domain-containing protein 6 (NLRP6) in Clostridium butyricum-regulated IBS induced by stress. Our results showed that NLRP6 was down-regulated in IBS group colon tissues. In addition, IL-18, IL-1β, myeloperoxidase (MPO), d-lactic acid (D-LA), and CD172a were up-regulated in the IBS group of colonic mucous. IL-18 and IL-1β were also increased after the NLRP6 gene was silenced. Pathological score suggested low inflammation of colonic mucous rather than terminal ileum. Water-avoidance stress (WAS) showed visceral hypersensitivity to colonic distension. However, treatment with Clostridium butyricum reversed these results, exerting a beneficial effect. In conclusion, Clostridium butyricum may exert a beneficial action on visceral hypersensitivity of IBS by inhibiting low grade inflammation of colonic mucous through its action on NLRP6.