Brain-gut axis: from basic understanding to treatment of IBS and related disorders

Differences in Prevalence and Psychosocial Characteristics of Irritable Bowel Syndrome According to Rome III and Rome IV Criteria in Medical and Nursing Students

Background/Aims

In Korea, changes in the prevalence of irritable bowel syndrome (IBS) after the Rome IV update have not been extensively studied. The aim of this study is to compare the prevalence and psychosocial risk factors of IBS according to Rome III and Rome IV criteria in medical and nursing students.

Methods

From August 13, 2021 to October 22, 2021, participants were enrolled and surveyed online. The survey includes general and specific questions for disease diagnosis and regarding participants' social and psychological characteristics using the 36-item short form survey, the Brief Encounter Psychosocial Instrument-Korean version, and the Hospital Anxiety and Depression Scale.

Results

In total, 338 medical students and 102 nursing students completed the survey. IBS was diagnosed in 78 students (17.7%) using Rome III criteria and in 51 students (11.6%) using Rome IV criteria. Significant differences in physical functioning score and severity score were observed between patients diagnosed using Rome IV criteria and patients diagnosed using Rome III criteria. Multiple logistic regression revealed that severity score (adjusted odds ratio = 1.01; 95% confidence interval: 1.00-1.21; P = 0.022) is the only predictor of IBS that differentiates Rome IV criteria from Rome III criteria.

Conclusions

Even after updating the Rome IV diagnostic criteria, the prevalence of IBS in medical and nursing students in Korea remained high. Patients who met the Rome IV criteria had more severe symptoms and lower quality of life than patients who met the Rome III criteria.

ZO-1 and IL-1RAP Phosphorylation: Potential Role in Mediated Brain-Gut Axis Dysregulation in Irritable Bowel Syndrome-like Stressed Mice

Background and Objectives: Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder often exacerbated by stress, influencing the brain-gut axis (BGA). BGA dysregulation, disrupted intestinal barrier function, altered visceral sensitivity and immune imbalance defects underlying IBS pathogenesis have been emphasized in recent investigations. Phosphoproteomics reveals unique phosphorylation details resulting from environmental stress. Here, we employ phosphoproteomics to explore the molecular mechanisms underlying IBS-like symptoms, mainly focusing on the role of ZO-1 and IL-1RAP phosphorylation. Materials and Methods: Morris water maze (MWM) was used to evaluate memory function for single prolonged stress (SPS). To assess visceral hypersensitivity of IBS-like symptoms, use the Abdominal withdrawal reflex (AWR). Colonic bead expulsion and defecation were used to determine fecal characteristics of the IBS-like symptoms. Then, we applied a phosphoproteomic approach to BGA research to discover the molecular mechanisms underlying the process of visceral hypersensitivity in IBS-like mice following SPS. ZO-1, p-S179-ZO1, IL-1RAP, p-S566-IL-1RAP and GFAP levels in BGA were measured by western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay to validate phosphorylation quantification. Fluorescein isothiocyanate-dextran 4000 and electron-microscopy were performed to observe the structure and function of the intestinal epithelial barrier. Results: The SPS group showed changes in learning and memory ability. SPS exposure affects visceral hypersensitivity, increased fecal water content, and significant diarrheal symptoms. Phosphoproteomic analysis displayed that p-S179-ZO1 and p-S566-IL-1RAP were significantly differentially expressed following SPS. In addition, p-S179-ZO1 was reduced in mice's DRG, colon, small intestine, spinal and hippocampus and intestinal epithelial permeability was increased. GFAP, IL-1β and p-S566-IL-1RAP were also increased at the same levels in the BGA. And IL-1β showed no significant difference was observed in serum. Our findings reveal substantial alterations in ZO-1 and IL-1RAP phosphorylation, correlating with increased epithelial permeability and immune imbalance. Conclusions: Overall, decreased p-S179-ZO1 and increased p-S566-IL-1RAP on the BGA result in changes to tight junction structure, compromising the structure and function of the intestinal epithelial barrier and exacerbating immune imbalance in IBS-like stressed mice.

Hemorrhoidal disease and its genetic association with depression, bipolar disorder, anxiety disorders, and schizophrenia: a bidirectional mendelian randomization study

BACKGROUND

Hemorrhoids and psychiatric disorders exhibit high prevalence rates and a tendency for relapse in epidemiological studies. Despite this, limited research has explored their correlation, and these studies are often subject to reverse causality and residual confounding. We conducted a Mendelian randomization (MR) analysis to comprehensively investigate the association between several mental illnesses and hemorrhoidal disease.

METHODS

Genetic associations for four psychiatric disorders and hemorrhoidal disease were obtained from large consortia, the FinnGen study, and the UK Biobank. Genetic variants associated with depression, bipolar disorder, anxiety disorders, schizophrenia, and hemorrhoidal disease at the genome-wide significance level were selected as instrumental variables. Screening for potential confounders in genetic instrumental variables using PhenoScanner V2. Bidirectional MR estimates were employed to assess the effects of four psychiatric disorders on hemorrhoidal disease.

RESULTS

Our analysis revealed a significant association between genetically predicted depression and the risk of hemorrhoidal disease (IVW, OR=1.20,95% CI=1.09 to 1.33, P <0.001). We found no evidence of associations between bipolar disorder, anxiety disorders, schizophrenia, and hemorrhoidal disease. Inverse MR analysis provided evidence for a significant association between genetically predicted hemorrhoidal disease and depression (IVW, OR=1.07,95% CI=1.04 to 1.11, P <0.001).

CONCLUSIONS

This study offers MR evidence supporting a bidirectional causal relationship between depression and hemorrhoidal disease.

Pharmacological Management for Pediatric Irritable Bowel Syndrome: A Review

Irritable bowel syndrome is a multifactorial disease with chronic symptoms that interfere with the quality of life of patients. It represents one of the most common causes of functional abdominal pain in the pediatric population. Various theses with little evidence tried to explain the pathophysiology of the disease. Neurological origin was one of the theories explaining the disease, either by the disturbance of neurotransmitters like dopamine, noradrenaline, and serotonin, which have some evidence of their relation to GI tract functions. Other factors like bio-psycho-social factors that affect the pediatric population are represented in bullying, unrealistic academic expectations from the parents, continuous educational stress, and difficult relationships with peers. Other factors may be genetic abnormalities of the receptors or visceral hypersensitivity. Treatment strategies for the disease varied from physical activity like yoga to a diet like a low-FODMAP diet. Pharmacological treatment of the disease targets the presenting symptoms, represented by antispasmodic drugs treating abdominal pain/discomfort, antipsychotics that regulate the disturbance in the brain-gut axis, and other drugs targeting diarrhea or constipation that present with the patient according to the type of IBS and the condition of the patient.

Lower gastric sensitivity in quiescent inflammatory bowel disease than in irritable bowel syndrome

OBJECTIVE

Visceral hypersensitivity is considered a key symptom in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), both of which seriously affect health-related quality of life (HrQoL). Previous findings are mostly based on invasive procedures that may interfere with the assessment of visceral perception. The current study, therefore, investigates whether IBD and IBS are characterized by altered perception of 'natural' gastric distensions ('interoception').

METHODS

Twenty IBD patients in remission (13 Crohn's disease, 7 ulcerative colitis), 12 IBS patients, and 20/12 matched healthy control (HC) individuals, respectively, underwent the water load test, in which they could drink ad libitum until the subjective thresholds of satiation (stage 1) and fullness (stage 2) were reached. Gastric motility was assessed using electrogastrography.

RESULTS

IBD patients drank significantly more water until satiation than IBS patients, whereas no differences between patients and HC groups were observed. Electrogastrographic patterns were comparable between groups, suggesting no pathologies in gastric motility in IBD or IBS. The amount of water consumed until satiation negatively correlated with HrQoL related to bowel symptoms in IBD patients, but was positively associated with emotional well-being in IBS patients.

CONCLUSION

Our findings implicate relative gastric hypersensitivity in IBS, and relative hyposensitivity in IBD patients, which are both related to specific HrQoL aspects.

Systematic review with meta-analysis: Stress-management interventions for patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder of unknown pathological origin that is associated with psychological distress and reduced health-related quality of life (HRQoL). We investigated the effects of stress-management for adults with IBS on typical symptoms, HRQoL and mental health. With predefined criteria (patients: adults with IBS; intervention: stress-management; control: care as usual or waitlist; outcome: patient-relevant; study-type: controlled trials), we registered the study with PROSPERO (168030) and searched the main medical databases. Two researchers independently reviewed the publications and assessed the risk of bias using the Scottish Intercollegiate Guidelines Network checklist. We performed meta-analysis with homogeneous trials of acceptable quality. After screening 6656 publications, ten suitable randomized trials of acceptable (n = 5) or low methodological quality (n = 5) involving 587 patients were identified. Our meta-analysis showed no effect of stress-management on IBS severity 1-2 months after the intervention (Hedges' g = -0.23, 95%-CI = -0.84 to -0.38, I2  = 86.1%), and after 3-12 months (Hedges' g = -0.77, 95%-CI = -1.77 to -0.23, I2  = 93.3%). One trial found a short-term reduction of symptoms, and one trial found symptom relief in the long-term (at 6 months). One of two studies that examined HRQoL found an improvement (after 2 months). One of two studies that examined depression and anxiety found a reduction of these symptoms (after 3 weeks). Stress-management may be beneficial for patients with IBS regarding the short-term reduction of bowel and mental health symptoms, whereas long-term benefits are unclear. Good quality RCTs with more than 6 months follow-up are needed.

Association between Serum Vitamin D and Irritable Bowel Syndrome Symptoms in a Sample of Adults

Vitamin D may be associated with irritable bowel syndrome (IBS) pathways. This cross-sectional study evaluated the associations between serum Vitamin D and IBS symptoms in a sample of Lebanese adults. Participants (n = 230; mean (SD) age: 43.36 (16.05) years, 62.9% females) were adults, free of diseases affecting Vitamin D metabolism, and recruited from a large university and the surrounding community. Serum Vitamin D (25-hydroxyvitamin D) was assessed using an automated chemiluminescence micro-particle immunoassay kit. The Birmingham IBS Symptom Questionnaire total scale, and pain, constipation, and diarrhea subscales were used to study IBS symptoms. Four linear regression analyses were performed, taking respectively the total scale and each of the subscales as the dependent variable. Vitamin D was forced into each model. Covariates included sociodemographic and medical variables, fluid intake, physical activity, sleep quality, stress, and adherence to the Mediterranean diet. Mean (SD) serum Vitamin D was 17.53 (12.40) ng/mL and mean (SD) Birmingham IBS Symptom Questionnaire was 16.98 (15.16) (pain: 20.75 (23.63), constipation: 25.06 (29.99), diarrhea: 9.88 (13.37)). Serum Vitamin D was not associated with the total score, nor with any of the subscales (p > 0.05 for the four regression analyses). Serum Vitamin D was not associated with IBS symptoms in a sample of Lebanese adults, adding to the controversy in this field. Further understanding of the pathophysiological mechanisms involved in Vitamin D and IBS is warranted.

Psychosocial Interventions for the Treatment of Functional Abdominal Pain Disorders in Children: A Systematic Review and Meta-analysis

Importance

Functional abdominal pain disorders (FAPDs) can severely affect the life of children and their families, with symptoms carrying into adulthood. Management of FADP symptoms is also a financial and time burden to clinicians and health care systems.

Objective

To systematically review various randomized clinical trials (RCTs) on the outcomes of cognitive behavioral therapy (CBT), educational support, yoga, hypnotherapy, gut-directed hypnotherapy, guided imagery, and relaxation in the management of FAPDs.

Data Sources

PubMed, MEDLINE, Embase, PsycINFO, and Cochrane Library.

Study Selection

All RCTs that compared psychosocial interventions with any control or no intervention, for children aged 4 to 18 years with FAPDs.

Data Extraction and Synthesis

Pairs of the authors independently extracted data of all included studies, using a predesigned data extraction sheet. One author acted as arbitrator. Risk of bias was assessed using the Cochrane risk of bias tool, and certainty of the evidence for all primary outcomes was analyzed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) framework.

Main Outcomes and Measures

Primary outcomes were treatment success, pain frequency, pain intensity, and withdrawal owing to adverse events. Dichotomous outcomes were expressed as risk ratio (RR) with corresponding 95% CIs. Continuous outcomes were expressed as mean difference (MD) or standardized MD with 95% CI.

Results

A total of 33 RCTs with 2657 children (median [range] age, 12 [7-17] years; 1726 girls [67.3%]) were included. Twelve studies compared CBT with no intervention, 5 studies compared CBT with educational support, 3 studiescompared yoga with no intervention, 2 studies compared hypnotherapy with no intervention, 2 studies compared gut-directed hypnotherapy with hypnotherapy, and 2 studies compared guided imagery with relaxation. Seven studies evaluated other unique comparisons (eg, visceral osteopathy vs normal osteopathy). Per the GRADE framework, owing to risk of bias, there was moderate certainty in evidence that CBT was associated with higher treatment success numbers (n = 324 children; RR, 2.37; 95% CI 1.30-4.34; number needed to treat [NNT] = 5), lower pain frequency (n = 446 children; RR, -0.36; 95% CI, -0.63 to -0.09), and lower pain intensity (n = 332 children; RR, -0.58; 95% CI, -0.83 to -0.32) than no intervention. Owing to high imprecision, there was low certainty in evidence that there was no difference between CBT and educational support for pain intensity (n = 127 children; MD, -0.36; 95% CI, -0.87 to 0.15). Owing to risk of bias and imprecision, there was low certainty in evidence that hypnotherapy resulted in higher treatment success compared with no intervention (n = 91 children; RR, 2.86; 95% CI, 1.19-6.83; NNT = 5). Owing to risk of bias and imprecision, there was low certainty in evidence that yoga had similar treatment success to no intervention (n = 99 children; RR, 1.09; 95% CI, 0.58-2.08).

Conclusions and Relevance

Results of this systematic review and meta-analysis suggest that CBT and hypnotherapy may be considered as a treatment for FAPDs in childhood. Future RCTs should address quality issues to enhance the overall certainty of the results, and studies should consider targeting these interventions toward patients who are more likely to respond.

Therapeutic potential of serotonin 4 receptor for chronic depression and its associated comorbidity in the gut

The latest estimates from world health organization suggest that more than 450 million people are suffering from depression and other psychiatric conditions. Of these, 50-60% have been reported to have progression of gut diseases. In the last two decades, researchers introduced incipient physiological roles for serotonin (5-HT) receptors (5-HTRs), suggesting their importance as a potential pharmacological target in various psychiatric and gut diseases. A growing body of evidence suggests that 5-HT systems affect the brain-gut axis in depressive patients, which leads to gut comorbidity. Recently, preclinical trials of 5-HT4R agonists and antagonists were promising as antipsychotic and prokinetic agents. In the current review, we address the possible pharmacological role and contribution of 5-HT4R in the pathophysiology of chronic depression and associated gut abnormalities. Physiologically, during depression episodes, centers of the sympathetic and parasympathetic nervous system couple together with neuroendocrine systems to alter the function of hypothalamic-pituitary-adrenal (HPA) axis and enteric nervous system (ENS), which in turn leads to onset of gastrointestinal tract (GIT) disorders. Consecutively, the ENS governs a broad spectrum of physiological activities of gut, such as visceral pain and motility. During the stages of emotional stress, hyperactivity of the HPA axis alters the ENS response to physiological and noxious stimuli. Consecutively, stress-induced flare, swelling, hyperalgesia and altered reflexes in gut eventually lead to GIT disorders. In summary, the current review provides prospective information about the role and mechanism of 5-HT4R-based therapeutics for the treatment of depressive disorder and possible consequences for the gut via brain-gut axis interactions. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.

Utility of animal gastrointestinal motility and transit models in functional gastrointestinal disorders

Alteration in the gastrointestinal (GI) motility and transit comprises an important component of the functional gastrointestinal disorders (FGID). Available animal GI motility and transit models are to study symptoms (delayed gastric emptying, constipation, diarrhea) rather than biological markers to develop an effective treatment that targets the underlying mechanism of altered GI motility in patients. Animal data generated from commonly used methods in human like scintigraphy, breath test and wireless motility capsule may directly translate to the clinic. However, species differences in the control mechanism or pharmacological responses of GI motility may compromise the predictive and translational value of the preclinical data to human. In this review we aim to provide a summary on animal models used to mimic GI motility alteration in FGID, and the impact of the species differences in the physiological and pharmacological responses on the translation of animal GI motility and transit data to human.

High Rates of Non-Response Across Treatment Attempts in Chronic Irritable Bowel Syndrome: Results From a Follow-Up Study in Tertiary Care

Objective: Despite a wealth of treatment options for irritable bowel syndrome (IBS), data on the subjective experience of treatments in ongoing clinical practice are sparse. This follow-up study assessed the individual usage of treatment modalities by IBS patients over time and investigated the patients' subjective experience of therapeutic impact. Methods: The study was conducted at the Specialty Clinic for Functional Gastrointestinal Disorders of the Heidelberg University Hospital. All patients who fulfilled the Rome III criteria for IBS and treated in our outpatient clinic between January 2012 and December 2016 were invited to the assessment. The primary outcome variables were individual usage of treatment modalities and the Patient Global Impression of Change (PGIC) with treatments. Results: Three hundred and sixty-six patients fulfilled the Rome III criteria for IBS and thus were eligible for this study. Two hundred and seven patients dropped out from the study. The study could include 159 patients (43.7 ± 17.1 years; 71.1% female). The mean time since the first visit to the clinic was 2.8 ± 1.3 years (median 3.0 years). The mean time of symptom duration was 14.1 ± 11.1 years (median 10 years). The average number of treatment attempts was 12, ranging from 2 to 39). With respect to the subjective experience of therapeutic impact, there were no significant differences in the PGIC scores among different treatments (p = 0.183). The rates of non-response rates (minimally improved, no change, or minimally worse) ranged from 63.0% to 83.9%. The PGIC score was correlated negatively with the mean number of treatment attempts (r = -0.316, p < 0.01). The mean number of treatment attempts was correlated negatively with quality of life (r = -0.262, p < 0.01). Conclusion: A multidisciplinary treatment approach of IBS is characterized by high rates of non-response and a high number of frustrating treatment attempts. The connection between the various treatment attempts and the frustrating subjective experience of therapeutic impact puts a substantial burden on IBS patients.

Brain-Gut Axis: Clinical Implications

This article provides an overarching view of what is currently known about the physiology of the brain-gut axis in both health and disease and how these concepts apply to irritable bowel syndrome, the most common functional gastrointestinal disorder in pediatrics.

Hirschsprung disease - integrating basic science and clinical medicine to improve outcomes

Hirschsprung disease is defined by the absence of enteric neurons at the end of the bowel. The enteric nervous system (ENS) is the intrinsic nervous system of the bowel and regulates most aspects of bowel function. When the ENS is missing, there are no neurally mediated propulsive motility patterns, and the bowel remains contracted, causing functional obstruction. Symptoms of Hirschsprung disease include constipation, vomiting, abdominal distension and growth failure. Untreated disease usually causes death in childhood because bloodstream bacterial infections occur in the context of bowel inflammation (enterocolitis) or bowel perforation. Current treatment is surgical resection of the bowel to remove or bypass regions where the ENS is missing, but many children have problems after surgery. Although the anatomy of Hirschsprung disease is simple, many clinical features remain enigmatic, and diagnosis and management remain challenging. For example, the age of presentation and the type of symptoms that occur vary dramatically among patients, even though every affected child has missing neurons in the distal bowel at birth. In this Review, basic science discoveries are linked to clinical manifestations of Hirschsprung disease, including partial penetrance, enterocolitis and genetics. Insights into disease mechanisms that might lead to new prevention, diagnostic and treatment strategies are described.

Migraine in young females with irritable bowel syndrome: still a challenge

Migraine without aura is frequently reported in female patients with irritable bowel syndrome (IBS), but knowledge about the relationship between these two conditions is still lacking. This study was aimed to explore the particularities of migraine without aura in young female patients with IBS in order to establish a possible link between them. From a cohort of young female patients hospitalized with IBS in the Internal Medicine Department, 30 joined this pilot study, and they were assigned into two groups on the basis of presence or absence of migraine. In this sample, 15 patients have mild to moderate migraine without aura, with a recently taken normal brain scan, and 15 were without migraine. Diseases and conditions not related to migraine and other possible specific female comorbidities were ruled out. Patients undertook a thorough clinical examination in order to assess fibromyalgia (FM) and chronic pelvic pain (CPP), Questionnaires for migraine disability assessment (MIDAS) and generalized anxiety disorder (GAD) were performed. Laboratory testing of blood, urine, and stool were also performed. Optimized lymphocyte proliferation test for food allergy (FA) and a fecal microbiota (microbiological semiquantitative method) for dysbiosis (DB) assessment were performed. Based on the results, migraine-positive group displayed more severe comorbidities: FM (p=0.0002), FA (p=0.0006), CPP (p=0.026), higher scores of anxiety (GAD, p=0.0008), and more severe DB (p=0.0009). We noticed a strong positive correlation between MIDAS and GAD (r=0.83), a good positive correlation between MIDAS and DB (r=0.56), and a moderate positive correlation between MIDAS, FM, and FA (r=0.46 and 0.41). In conclusion, young female patients with IBS and migraine without aura displayed more severe associated issues - anxiety, intestinal DB, FM, FA, and CPP. The severity of migraine correlated well with anxiety range and DB magnitude and moderately with FM and FA.

Coping Skills Are Associated With Gastrointestinal Symptom Severity and Somatization in Patients With Irritable Bowel Syndrome

BACKGROUND & AIMS

Coping resources and processes are altered in patients with irritable bowel syndrome (IBS). We investigated the relationship between coping resources and gastrointestinal (GI) and extraintestinal symptom severity in patients with IBS and potential mediators of this relationship.

METHODS

We performed a cross-sectional study of 216 patients with IBS attending a secondary/tertiary care specialized outpatient center in Sweden from 2003 through 2007. We collected data on coping resources, levels of anxiety (general and GI specific), depressive symptoms, levels of GI symptoms, and extraintestinal somatic symptoms (somatization) by administering validated self-report questionnaires. General Linear Models were used to assess associations and mediation.

RESULTS

GI symptoms: low levels of physical coping resources (practice of activities that are beneficial for health; P = .0016), high levels of general anxiety symptoms (P = .033), and GI-specific anxiety symptoms (P < .0001), but not depressive symptoms (P = .89), were independently associated with GI symptom levels (R² = 0.31). Anxiety and GI-specific anxiety partially mediated the effect of physical coping. Somatization: low levels of physical coping resources (P = .003), high levels of anxiety (P = .0147), depressive (P = .0005), and GI-specific anxiety symptoms (P = .06) were associated with somatization levels (R² = 0.35). Levels of general and GI-specific anxiety and depressive symptoms partially mediated this physical coping effect. The effect of psychological coping resources (including optimism, social support, and accepting/expressing emotions) on somatization levels was not significant (P = .98), but was fully mediated by levels of anxiety and depressive symptoms, and partially by levels of GI-specific anxiety symptoms.

CONCLUSIONS

In a cross-sectional study of patients with IBS in Sweden, we found associations of levels of coping resources with GI and extraintestinal symptom severity; these associations were mediated by levels of anxiety and depressive symptoms. Although confirmation in longitudinal studies is needed, this identifies coping as a potential psychological treatment target in IBS.

A NMDA-receptor calcium influx assay sensitive to stimulation by glutamate and glycine/D-serine

N-methyl-D-aspartate-receptors (NMDARs) are ionotropic glutamate receptors that function in synaptic transmission, plasticity and cognition. Malfunction of NMDARs has been implicated in a variety of nervous system disorders, making them attractive therapeutic targets. Overexpression of functional NMDAR in non-neuronal cells results in cell death by excitotoxicity, hindering the development of cell-based assays for NMDAR drug discovery. Here we report a plate-based, high-throughput approach to study NMDAR function. Our assay enables the functional study of NMDARs with different subunit composition after activation by glycine/D-serine or glutamate and hence presents the first plate-based, high throughput assay that allows for the measurement of NMDAR function in glycine/D-serine and/or glutamate sensitive modes. This allows to investigate the effect of small molecule modulators on the activation of NMDARs at different concentrations or combinations of the co-ligands. The reported assay system faithfully replicates the pharmacology of the receptor in response to known agonists, antagonists, positive and negative allosteric modulators, as well as the receptor’s sensitivity to magnesium and zinc. We believe that the ability to study the biology of NMDARs rapidly and in large scale screens will enable the identification of novel therapeutics whose discovery has otherwise been hindered by the limitations of existing cell based approaches.

Neuroendocrine Dysregulation in Irritable Bowel Syndrome Patients: A Pilot Study

Background/Aims

Irritable bowel syndrome (IBS) is a multifactorial disorder, involving dysregulation of brain-gut axis. Our aim was to evaluate the neuroendocrine activity in IBS.

Methods

Thirty IBS and 30 healthy volunteers were enrolled. Psychological symptoms were evaluated by questionnaires. Urinary 5-hydroxyindoleacetic acid, plasma serotonin (5-hydroxytryptamine, 5-HT), endothelin, and neuropeptide Y (NPY), and plasma and urinary cortisol levels were evaluated. Fourteen IBS subjects underwent microneurography to obtain multiunit recordings of efferent postganglionic muscle sympathetic nerve activity (MSNA).

Results

Prevalent psychological symptoms in IBS were maladjustment (60%), trait (40%) and state (17%) anxiety, obsessive compulsive-disorders (23%), and depressive symptoms (23%). IBS showed increased NPY (31.9 [43.7] vs 14.8 [18.1] pmol/L, P = 0.006), 5-HT (214.9 [182.6] vs 141.0 [45.5] pg/mL, P = 0.010), and endothelin [1.1 [1.4] vs 2.1 [8.1] pg/mL, P = 0.054], compared to healthy volunteers. Moreover, plasma NPY, endothelin, cortisol and 5-HT, and urinary 5-hydroxyindoleacetic acid were associated with some psychological disorders (P ≤ 0.05). Despite a similar resting MSNA, after cold pressor test, IBS showed a blunted increase in MSNA burst frequency (+4.1 vs +7.8 bursts/min, P = 0.048; +30.1% vs +78.1%, P = 0.023). Baseline MSNA tended to be associated with urinary cortisol (ρ = 0.557, P = 0.059). Moreover, changes in heart rate after mental stress were associated with urinary cortisol (ρ = 0.682, P = 0.021) and changes in MSNA after mental stress were associated with plasma cortisol (ρ = 0.671, P = 0.024).”

Conclusion

Higher concentrations of endothelin, NPY, and 5-HT were found to be associated with some psychological disorders in IBS patients together with an altered cardiovascular autonomic reactivity to acute stressors compared to healthy volunteers.

The Gut Microbiome in Irritable Bowel Syndrome and Other Functional Bowel Disorders

Emerging data from epidemiologic, microbiome, and physiology research in patients with functional bowel disorders (FBDs) provide evidence for a linkage between alterations in the intestinal microbiota and FBDs. However, currently most of the data is based on association studies, and the causality role of the microbiota in these disorders is not established. Growing evidence for compositional changes and the increasing recognition of the association between the intestinal microbiota and gut-brain functions that are relevant to the pathophysiology and/or clinical symptoms of FBDs have led to increased interest in manipulating the intestinal microbiota for the treatment of these disorders.

Pathogenesis, Experimental Models and Contemporary Pharmacotherapy of Irritable Bowel Syndrome: Story About the Brain-Gut Axis

Background

Although the precise pathophysiology of irritable bowel syndrome (IBS) remains unknown, it is generally considered to be a disorder of the brain-gut axis, representing the disruption of communication between the brain and the digestive system. The present review describes advances in understanding the pathophysiology and experimental approaches in studying IBS, as well as providing an update of the therapies targeting brain-gut axis in the treatment of the disease.

Methods

Causal factors of IBS are reviewed. Following this, the preclinical experimental models of IBS will be introduced. Besides, both current and future therapeutic approaches of IBS will be discussed.

Results

When signal of the brain-gut axis becomes misinterpreted, it may lead to dysregulation of both central and enteric nervous systems, altered intestinal motility, increased visceral sensitivity and consequently contributing to the development of IBS. Interference of the brain-gut axis can be modulated by various psychological and environmental factors. Although there is no existing animal experiment that can represent this complex multifactorial disease, these in vivo models are clinically relevant readouts of gastrointestinal functions being essential to the identification of effective treatments of IBS symptoms as well as their molecular targets. Understanding the brain-gut axis is essential in developing the effective therapy for IBS. Therapies include improvement of GI motor functions, relief of visceral hypersensitivity and pain, attenuation of autonomic dysfunctions and suppression of mucosal immune activation.

Conclusion

Target-oriented therapies that provide symptomatic, psychological and physiological benefits could surely help to improve the quality of life of IBS patients.

Implementing psychological therapies for functional GI disorders in children and adults

INTRODUCTION

Functional GI disorders (FGIDs) are common in adults and children. Psychological factors play an important role in the onset and maintenance of FGIDs and in explaining the associated disability. Psychological treatments such as Cognitive Behavioral Therapy and Hypnotherapy have been found efficacious in FGIDs but Integrating psychological treatments into traditionally medically-oriented care can be challenging.

AREAS COVERED

This review outlines the case for integrating psychological therapies into medical care for FGIDs and examine various models of integrated care that can be adapted to fit specific practice scenarios. Expert commentary: We advise integrating a psychologist in the care and treatment planning of every patient. Clinic-specific needs dictate how integrated care for patients with FGIDs can be delivered.

Maternal Weaning Modulates Emotional Behavior and Regulates the Gut-Brain Axis

Evidence shows that nutritional and environmental stress stimuli during postnatal period influence brain development and interactions between gut and brain. In this study we show that in rats, prevention of weaning from maternal milk results in depressive-like behavior, which is accompanied by changes in the gut bacteria and host metabolism. Depressive-like behavior was studied using the forced-swim test on postnatal day (PND) 25 in rats either weaned on PND 21, or left with their mother until PND 25 (non-weaned). Non-weaned rats showed an increased immobility time consistent with a depressive phenotype. Fluorescence in situ hybridization showed non-weaned rats to harbor significantly lowered Clostridium histolyticum bacterial groups but exhibit marked stress-induced increases. Metabonomic analysis of urine from these animals revealed significant differences in the metabolic profiles, with biochemical phenotypes indicative of depression in the non-weaned animals. In addition, non-weaned rats showed resistance to stress-induced modulation of oxytocin receptors in amygdala nuclei, which is indicative of passive stress-coping mechanism. We conclude that delaying weaning results in alterations to the gut microbiota and global metabolic profiles which may contribute to a depressive phenotype and raise the issue that mood disorders at early developmental ages may reflect interplay between mammalian host and resident bacteria.

The Modulation of Potassium Channels in the Smooth Muscle as a Therapeutic Strategy for Disorders of the Gastrointestinal Tract

Alterations of smooth muscle contractility contribute to the pathophysiology of important functional gastrointestinal disorders (FGIDs) such as functional dyspepsia and irritable bowel syndrome. Consequently, drugs that decrease smooth muscle contractility are effective treatments for these diseases. Smooth muscle contraction is mainly triggered by Ca(2+) influx through voltage-dependent channels located in the plasma membrane. Thus, the modulation of the membrane potential results in the regulation of Ca(2+) influx and cytosolic levels. K(+) channels play fundamental roles in these processes. The open probability of K(+) channels increases in response to various stimuli, including membrane depolarization (voltage-gated K(+) [K(V)] channels) and the increase in cytosolic Ca(2+) levels (Ca(2+)-dependent K(+) [K(Ca)] channels). K(+) channel activation is mostly associated with outward K(+) currents that hyperpolarize the membrane and reduce cell excitability and contractility. In addition, some K(+) channels are open at the resting membrane potential values of the smooth muscle cells in some gut segments and contribute to set the resting membrane potential itself. The closure of these channels induces membrane depolarization and smooth muscle contraction. K(V)1.2, 1.5, 2.2, 4.3, 7.4 and 11.1, K(Ca)1.1 and 2.3, and inwardly rectifying type 6K(+) (K(ir)6) channels play the most important functional roles in the gastrointestinal smooth muscle. Activators of all these channels may theoretically relax the gastrointestinal smooth muscle and could therefore be promising new therapeutic options for FGID. The challenge of future drug research and development in this area will be to synthesize molecules selective for the channel assemblies expressed in the gastrointestinal smooth muscle.

Brain-Gut Axis Modulation of Acupuncture in Functional Dyspepsia: A Preliminary Resting-State fcMRI Study

Objective. To explore acupuncture effects on brain functional connectivity in patients with functional dyspepsia (FD). Methods. Eight patients in an acupuncture treatment group and ten healthy adults in the control group participated in the study. Acupuncture effectiveness was evaluated based on changes of the gastrointestinal symptoms, gastric motility measurements, and gastrin levels and comparisons with the control group when appropriate. To investigate functional connectivity changes related to FD and potential modulation after acupuncture, a set of regions of interest (ROIs) were selected according to previous fMRI reports of acupuncture. Results. Patients showed significant improvements of FD signs and symptoms after acupuncture treatments. For all of the ROIs, we identified subportions of the networks showing reduced connectivity in patients with FD. Connectivity between the ROIs and corresponding disease targets showed significant improvement after acupuncture treatment (P < 0.05) in all ROIs except for right medial temporal lobe-hippocampus and right inferior parietal lobule. Conclusion. Functional connectivity of the brain is changed in patients with FD but approximates that in healthy control after acupuncture treatment. The relief of gastrointestinal signs and symptoms by acupuncture is likely due to the normalization of brain-gut axis associated with FD.

Aspects of the non-pharmacological treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most commonly diagnosed gastrointestinal conditions. It represents a significant healthcare burden and remains a clinical challenge. Over the years IBS has been described from a variety of different perspectives; from a strict illness of the gastrointestinal tract (medical model) to a more complex multi-symptomatic disorder of the brain-gut axis (biopsychosocial/psychosomatic model). In this article we present aspects of the pathophysiology and the non-pharmacological treatment of IBS based on current knowledge. Effects of conditioned stress and/or traumatic influences on the emotional system (top-down) as well as effects on the intestine through stressors, infection, inflammation, food and dysbiosis (bottom-up) can affect brain-gut communication and result in dysregulation of the autonomic nervous system (ANS), playing an important role in the pathophysiology of IBS. Conditioned stress together with dysregulation of the autonomic nervous system and the emotional system may involve reactions in which the distress inside the body is not recognized due to low body awareness. This may explain why patients have difficulty identifying their symptoms despite dysfunction in muscle tension, movement patterns, and posture and biochemical functions in addition to gastrointestinal symptoms. IBS shares many features with other idiopathic conditions, such as fibromyalgia, chronic fatigue syndrome and somatoform disorders. The key to effective treatment is a thorough examination, including a gastroenterological examination to exclude other diseases along with an assessment of body awareness by a body-mind therapist. The literature suggests that early interdisciplinary diagnostic co-operation between gastroenterologists and body-mind therapists is necessary. Re-establishing balance in the ANS is an important component of IBS treatment. This article discusses the current knowledge of body-mind treatment, addressing the topic from a practical point of view.

Hypnosis Treatment of Gastrointestinal Disorders: A Comprehensive Review of the Empirical Evidence

Hypnotherapy has been investigated for 30 years as a treatment for gastrointestinal (GI) disorders. There are presently 35 studies in the published empirical literature, including 17 randomized controlled trials (RCTs) that have assessed clinical outcomes of such treatment. This body of research is reviewed comprehensively in this article. Twenty-four of the studies have tested hypnotherapy for adult irritable bowel syndrome (IBS) and 5 have focused on IBS or abdominal pain in children. All IBS hypnotherapy studies have reported significant improvement in gastrointestinal symptoms, and 7 out of 10 RCTs in adults and all 3 RCTs in pediatric patient samples found superior outcomes for hypnosis compared to control groups. Collectively this body of research shows unequivocally that for both adults and children with IBS, hypnosis treatment is highly efficacious in reducing bowel symptoms and can offer lasting and substantial symptom relief for a large proportion of patients who do not respond adequately to usual medical treatment approaches. For other GI disorders the evidence is more limited, but preliminary indications of therapeutic potential can be seen in the single randomized controlled trials published to date on hypnotherapy for functional dyspepsia, functional chest pain, and ulcerative colitis. Further controlled hypnotherapy trials in those three disorders should be a high priority. The mechanisms underlying the impact of hypnosis on GI problems are still unclear, but findings from a number of studies suggest that they involve both modulation of gut functioning and changes in the brain's handling of sensory signals from the GI tract.

The role of AST-120 and protein-bound uremic toxins in irritable bowel syndrome: a therapeutic perspective

AST-120 (kremezin) exhibits its favourable effects in reducing the levels of renal toxins by selective adsorption of low molecular weight substances from the intestinal lumen. So far, a vast majority of studies were focused on the role of AST-120 in the treatment of chronic kidney diseases and cardiovascular disorders, and positive therapeutic effects of the agent have already been confirmed in clinical conditions. Up to the present, there are only a few studies regarding the role of AST-120 in irritable bowel syndrome (IBS). Compelling data suggest the ability of the compound to adsorb protein-bound uremic toxins and mast cell derived mediators and to modulate the farnesoid X receptor, which is a bile acid sensor indispensable for maintaining homeostasis in the intestine. In this review we focus on the actions of AST-120 on intestinal permeability, reduction of visceral sensitivity and alteration of gut motility. We also discuss whether AST-120 can mitigate common IBS symptoms, such as abdominal pain, bloating and malfunction of the colonic transit and thus improve the quality of life of patients with IBS.

Irritable Bowel Syndrome Increases the Risk of Epilepsy: A Population-Based Study

An abnormal interaction in the brain-gut axis is regarded as the cause of irritable bowel syndrome (IBS). We attempted to determine the association between IBS and subsequent development of epilepsy.A total of 32,122 patients diagnosed with IBS between 2000 and 2011 were identified from the Longitudinal Health Insurance Database as the study cohort, and 63,295 controls were randomly selected from the insurants without IBS and frequency-matched according to age, sex, and index year as the comparison cohort. Both cohorts were followed up until the end of 2011 to measure the incidence of epilepsy. We analyzed the risks of epilepsy using Cox proportional hazards regression models.The IBS patients had greater cumulative incidence of epilepsy than the cohort without IBS (log-rank test, P < 0.001 and 2.54 versus 1.86 per 1000 person-years). The IBS cohort had a higher risk of epilepsy after adjusting for age, sex, diabetes, hypertension, stroke, coronary artery disease, head injury, depression, systemic lupus erythematosus, brain tumor, and antidepressants usage (adjusted hazard ratio [aHR]: 1.30, 95% confidence interval [CI]: 1.17-1.45). Stratified by the presence of other risk factors, the relative risk was also greater for patients with (aHR: 1.25, 95% CI: 1.10-1.41) or without other risk factors (aHR: 1.68, 95% CI: 1.35-2.10) in the IBS cohort than for those in the non-IBS cohort. The age-specific relative risk of epilepsy in the IBS cohort was greater than that in the non-IBS cohort for both 35 to 49 age group and 50 to 64 age group (age ≤ 34, aHR:1.31, 95% CI: 0.93-1.85; age 35-49, aHR: 1.43, 95% CI: 1.12-1.83; age 50-64, aHR: 1.56, 95% CI: 1.27-1.91). However, there was no difference between patients > 65 years with IBS and those without IBS (aHR: 1.11, 95% CI: 0.94-1.31).This population-based cohort study revealed that IBS increases the risk of developing epilepsy. However, IBS may be less influential than other risk factors. Further study is necessary to clarify whether IBS is a risk factor or an epiphenomenon for epilepsy development.

Education and Hypnosis for Treatment of Functional Gastrointestinal Disorders (FGIDs) in Pediatrics

FGIDs in children and adolescents (ROME III classification) have a significant impact on the daily functioning and quality of life. Often it is the pain that is one of the main contributors to the burden of functional dyspepsia, functional abdominal pain (syndrome), and irritable bowel syndrome. Current knowledge confirms that a number of integrated networks at cortical and subcortical sites are responsible for the experience of pain. From the work of Mayer and Tillisch (2011), mainly based on structural and functional magnetic resonance imaging and positron emission tomography, it has become clear that abdominal pain syndromes are disorders of the bi-directional mind-brain-gut interactions. In this multi-factorial bio-psycho-social model we recognize the importance of neurobiological processes in the mind-brain-gut interactions, leading to alterations in motility, sensation, and immune functions. Medical treatment often offers little or no relief. Until now pharmaceutical research has not succeeded in developing safe new drugs with an effect on the brain-gut axis. More recent published research shows the rationale for the use of medical hypnosis in FGID. In this article the author will illustrate her specific approach in a pediatric gastroenterology clinic with children and adolescents with FGIDs. Being a pediatric gastroenterologist, the author emphasizes the importance of a clear diagnosis, explains the rationale for educating the patient and his or her parents on the multi-factorial bio-psycho-social model and the concepts of chronic pain, discusses the specific settings and pitfalls for hypnosis treatment in children, and last but not least, provides some examples of hypnotic sessions used with FGIDs.

Irritable bowel syndrome: an integrated explanatory model for clinical practice

BACKGROUND

Although irritable bowel syndrome (IBS) is a symptom-based diagnosis, clinicians' management of and communication about the disorder is often hampered by an unclear conceptual understanding of the nature of the problem. We aimed to elucidate an integrated explanatory model (EM) for IBS from the existing literature for pragmatic use in the clinical setting.

METHODS

Systematic and exploratory literature searches were performed in PubMed to identify publications on IBS and EMs.

KEY RESULTS

The searches did not identify a single, integrated EM for IBS. However, three main hypotheses were elucidated that could provide components with which to develop an IBS EM: (i) altered peripheral regulation of gut function (including sensory and secretory mechanisms); (ii) altered brain-gut signaling (including visceral hypersensitivity); and (iii) psychological distress. Genetic polymorphisms and epigenetic changes may, to some degree, underlie the etiology and pathophysiology of IBS and could increase the susceptibility to developing the disorder. The three model components also fit into one integrated explanation for abdominal symptoms and changes in stool habit. Additionally, IBS may share a common pathophysiological mechanism with other associated functional syndromes.

CONCLUSIONS & INFERENCES

It was possible to elucidate an integrated, three-component EM as a basis for clinicians to conceptualize the nature of IBS, with the potential to contribute to better diagnosis and management, and dialog with sufferers.

Low-FODMAP Diet for Irritable Bowel Syndrome: Is It Ready for Prime Time?

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disease, which adversely affects the quality of life. Its prevalence has been reported to be around 10-15 % in North America and constitutes the most common cause for gastroenterology referral. Unfortunately, the pathophysiology of IBS is not completely understood. Not surprisingly, the management strategies can leave the patients with inadequate symptom control, making IBS a debilitating gastrointestinal syndrome. Dietary interventions as a treatment strategy for IBS have been recently evaluated. One such intervention includes dietary restriction of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs). FODMAPs define a group of short-chain carbohydrates that are incompletely absorbed in small intestine and later fermented in the colon. Evidence in the form of randomized controlled trials and observational studies have evaluated the mechanism of action and efficacy of low-FODMAP diet. This dietary intervention has showed promising results in symptom reduction in IBS patients. However, latest trials have also shown that the low-FODMAP diet is associated with marked changes in gut microbiota specifically reduction in microbiota with prebiotic properties. Implications of such changes on gastrointestinal health need to be further evaluated in future trials.

More negative self-esteem and inferior coping strategies among patients diagnosed with IBS compared with patients without IBS--a case-control study in primary care

Background

Irritable Bowel Syndrome (IBS) is a chronic, relapsing gastrointestinal disorder, that affects approximately 10% of the general population and the majority are diagnosed in primary care. IBS has been reported to be associated with altered psychological and cognitive functioning such as mood disturbances, somatization, catastrophizing or altered visceral interoception by negative emotions and stress. The aim was to investigate the psychosocial constructs of self-esteem and sense of coherence among IBS patients compared to non-IBS patients in primary care.

Methods

A case–control study in primary care setting among IBS patients meeting the ROME III criteria (n = 140) compared to controls i.e. non-IBS patients (n = 213) without any present or previous gastrointestinal complaints. The data were collected through self-reported questionnaires of psychosocial factors.

Results

IBS-patients reported significantly more negative self-esteem (p < 0.001), lower scores for positive self-esteem (p < 0.001), and lower sense of coherence (p < 0.001) than the controls. The IBS-cases were also less likely to report ‘good’ health status (p < 0.001) and less likely to report a positive belief in the future (p < 0.001). After controlling for relevant confounding factors in multiple regressions, the elevation in negative self-esteem among IBS patients remained statistically significant (p = 0.02), as did the lower scores for sense of coherence among IBS cases (p = 0.04).

Conclusions

The more frequently reported negative self-esteem and inferior coping strategies among IBS patients found in this study suggest the possibility that psychological therapies might be helpful for these patients. However these data do not indicate the causal direction of the observed associations. More research is therefore warranted to determine whether these psychosocial constructs are more frequent in IBS patients.

Increased colonic bile acid exposure: a relevant factor for symptoms and treatment in IBS

OBJECTIVE

Bile acids may play a role in the pathogenesis of IBS. We investigated the potential effects of bile acids entering the colon and its role in the symptom pattern in IBS.

DESIGN

We measured 75Se-labelled homocholic acid-taurine (75SeHCAT) retention, and serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor (FGF) 19 in patients with IBS (n=141) and control subjects (75SeHCAT n=29; C4 and FGF19 n=435). In patients with IBS stool frequency and form, as well as GI symptom severity were registered, and in a proportion of patients colonic transit time and rectal sensitivity were measured (n=66). An 8-week open-label treatment with colestipol was offered to patients with 75SeHCAT <20%, and the effect of treatment was evaluated with IBS severity scoring system and adequate relief of IBS symptoms.

RESULTS

Compared with controls, patients with IBS had lower 75SeHCAT values (p=0.005), higher C4c levels (C4 corrected for cholesterol) (p<0.001), but similar FGF19 levels. Abnormal 75SeHCAT retention (<10%) was seen in 18% of patients, whereas 23% had elevated C4c levels. Patients with IBS with 75SeHCAT retention <10% had more frequent stools, accelerated colonic transit time, rectal hyposensitivity, a higher body mass index, higher C4c and lower FGF19 levels. Colestipol treatment improved IBS symptoms (IBS severity scoring system 220±109 vs. 277±106; p<0.01), and 15/27 patients fulfilled criteria for treatment response (adequate relief ≥50% of weeks 5-8).

CONCLUSIONS

Increased colonic bile acid exposure influences bowel habit and colonic transit time in patients with IBS. A high response rate to open label treatment with colestipol supports this, but placebo-controlled studies are warranted.

Allergy-related diseases and recurrent abdominal pain during childhood - a birth cohort study

BACKGROUND

Allergy and immune dysregulation may have a role in the pathophysiology of recurrent abdominal pain of functional origin, but previous studies of allergy-related diseases and abdominal pain have contradictory results.

AIM

To examine the association between allergy-related diseases or sensitisation during childhood and abdominal pain at age 12 years.

METHODS

In this birth cohort study of 4089 children, parents answered questionnaires regarding asthma, allergic rhinitis, eczema and food hypersensitivity ('allergy-related diseases') at ages 0,1,2,4,8 and 12 years. Blood for analyses of allergen-specific IgE was sampled at 4 and 8 years. At 12 years, the children answered questions regarding abdominal pain. Children with coeliac disease or inflammatory bowel disease were excluded. Associations were examined using multivariable logistic regression.

RESULTS

Among 2610 children with complete follow-up, 9% (n = 237) reported abdominal pain at 12 years. All allergy-related diseases were associated with concurrent abdominal pain at 12 years and the risk increased with increasing number of allergy-related diseases (P for trend <0.001). Asthma at 1 and 2 years and food hypersensitivity at 8 years were significantly associated with abdominal pain at 12 years. There was an increased risk of abdominal pain at 12 years in children sensitised to food allergens at 4 or 8 years, but in stratified analyses, this was confined to children whose parents had not reported food hypersensitivity at time of sensitisation.

CONCLUSION

Allergy-related diseases as well as sensitisation to food allergens were associated with an elevated risk of abdominal pain, and the risk increased with the number of allergy-related diseases.

Impact of psychological stress on irritable bowel syndrome

Psychological stress is an important factor for the development of irritable bowel syndrome (IBS). More and more clinical and experimental evidence showed that IBS is a combination of irritable bowel and irritable brain. In the present review we discuss the potential role of psychological stress in the pathogenesis of IBS and provide comprehensive approaches in clinical treatment. Evidence from clinical and experimental studies showed that psychological stresses have marked impact on intestinal sensitivity, motility, secretion and permeability, and the underlying mechanism has a close correlation with mucosal immune activation, alterations in central nervous system, peripheral neurons and gastrointestinal microbiota. Stress-induced alterations in neuro-endocrine-immune pathways acts on the gut-brain axis and microbiota-gut-brain axis, and cause symptom flare-ups or exaggeration in IBS. IBS is a stress-sensitive disorder, therefore, the treatment of IBS should focus on managing stress and stress-induced responses. Now, non-pharmacological approaches and pharmacological strategies that target on stress-related alterations, such as antidepressants, antipsychotics, miscellaneous agents, 5-HT synthesis inhibitors, selective 5-HT reuptake inhibitors, and specific 5-HT receptor antagonists or agonists have shown a critical role in IBS management. A integrative approach for IBS management is a necessary.

Widespread hyperalgesia in adolescents with symptoms of irritable bowel syndrome: results from a large population-based study

Widespread hyperalgesia is well documented among adult patients with irritable bowel syndrome (IBS), but little is known about pain sensitivity among adolescents with IBS. We examined pain sensitivity in 961 adolescents from the general population (mean age 16.1 years), including pain threshold and tolerance measurements of heat (forearm) and pressure pain (fingernail and shoulder) and cold pressor tolerance (hand). Adolescents with IBS symptoms (Rome III criteria) had lower heat pain thresholds compared to controls after adjustments for sex, comorbid pain, and psychological distress (mean difference = -.8 °C; 95% confidence interval [CI] = -1.6 to -.04). Similar results were found for pressure pain threshold at the shoulder (mean difference = -46 kPa; 95% CI = -78 to -13) and fingernail (mean difference = -62 kPa; 95% CI = -109 to -15), and for an aggregate of all 3 threshold measures (z-score difference = -.4; 95% CI = -.6 to -.2), though pressure pain threshold differences were nonsignificant after the final adjustments for psychological distress. No difference of pain tolerance was found between the IBS cases and controls. Our results indicate that adolescents in the general population with IBS symptoms, like adults, have widespread hyperalgesia.

PERSPECTIVE

This is the first report of widespread hyperalgesia among adolescents with IBS symptoms in the general population, with lower pain thresholds found to be independent of sex and comorbid pain. Our results suggest that central pain sensitization mechanisms in IBS may contribute to triggering and maintaining chronic pain symptoms.

Subtypes of irritable bowel syndrome in children: prevalence at diagnosis and at follow-up

OBJECTIVES

To assess the prevalence of irritable bowel syndrome (IBS) subtypes in childhood at diagnosis and their changes over 1 year.

STUDY DESIGN

This is an observational, prospective, multicenter study. Consecutive pediatric patients with IBS, according to Rome III criteria, were enrolled over a 1-year period. Parents recorded weekly stool frequency and consistency and gastrointestinal and extraintestinal symptoms in a diary. Stool consistency was scored according to the Bristol Stool Form Scale. Children were evaluated after 2, 3, 6, and 12 months.

RESULTS

We enrolled 100 children with IBS (median age 9.9 years, range 4.2-16.7 years, 52 girls and 48 boys). At time of enrollment, constipation-IBS was the prevalent subtype (45%), with a prevalence of girls at 62% (P < .005); diarrhea-IBS was reported in 26% of children, with a prevalence of boys at 69% (P < .005); and alternating-IBS was described in 29% of children, without a difference between sexes. During the follow-up, 10% of patients changed their IBS subtypes at 2 months, 9% at 3 months, 7% at 6 months, and 6.3% at 12 months. Twenty-four percent of patients changed IBS subtype between the time of enrollment and 12 months.

CONCLUSIONS

Constipation-IBS is the prevalent subtype in children, with a higher frequency in girls. In boys, diarrhea-IBS is the most common subtype. It is important to acquire knowledge about IBS subtypes to design clinical trials that may eventually shed new light on suptype-specific approaches to this condition.

K+ channels as potential targets for the treatment of gastrointestinal motor disorders

K(+) channels play important functional roles in excitable cells, as neurons and muscle cells. The activation or inhibition of K(+) channels hyperpolarizes or depolarizes the cell membrane, respectively. These effects determine in the smooth muscle decrease or increase in Ca(2+) influx through voltage-gated Ca(2+) (CaV1.2) channels and relaxation or contraction, respectively. Recent studies highlight the importance of voltage-dependent type 7 K(+) (KV7 or KCNQ) channels in regulating muscle tone and contractility in stomach and colon. KV7 channels, that include 5 subtypes (KV7.1-7.5), are activated at relatively negative potential values, close to those of the resting membrane potential for the smooth muscle cells of some segments of the gastrointestinal tract. Thus, they contribute to set the resting membrane potential and their blockade induces increase in smooth muscle contractility in stomach and colon. In addition, KV7 channel activation produces profound relaxations of gastric and colonic smooth muscle. Therefore, KV7 channel activators could be used to relax the smooth muscle and relieve symptoms in diseases such as functional dyspepsia and irritable bowel syndrome with prevalent diarrhea. The discovery of activators selective for the channel subtypes present in the smooth muscle, mainly KV7.4 and 7.5, would allow avoiding adverse cardiac and nervous system effects. A further step forward would be characterizing putative differences among the KV7 channel subtypes expressed in the various smooth muscles and synthesizing molecules specific for the gastrointestinal smooth muscle.

Mechanisms and efficacy of dietary FODMAP restriction in IBS

IBS is a debilitating condition that markedly affects quality of life. The chronic nature, high prevalence and associated comorbidities contribute to the considerable economic burden of IBS. The pathophysiology of IBS is not completely understood and evidence to guide management is variable. Interest in dietary intervention continues to grow rapidly. Ileostomy and MRI studies have demonstrated that some fermentable carbohydrates increase ileal luminal water content and breath hydrogen testing studies have demonstrated that some carbohydrates also increase colonic hydrogen production. The effects of fermentable carbohydrates on gastrointestinal symptoms have also been well described in blinded, controlled trials. Dietary restriction of fermentable carbohydrates (popularly termed the 'low FODMAP diet') has received considerable attention. An emerging body of research now demonstrates the efficacy of fermentable carbohydrate restriction in IBS; however, limitations still exist with this approach owing to a limited number of randomized trials, in part due to the fundamental difficulty of placebo control in dietary trials. Evidence also indicates that the diet can influence the gut microbiota and nutrient intake. Fermentable carbohydrate restriction in people with IBS is promising, but the effects on gastrointestinal health require further investigation.

It's a gut feeling: how the gut microbiota affects the state of mind

Common human experience shows that stress and anxiety may modulate gut function. Such observations have been combined with an increasing evidence base that has culminated in the concept of the brain-gut axis. Nevertheless, it has not been until recently that the gut and its attendant components have been considered to influence higher cerebral function and behaviour per se. Moreover, the proposal that the gut and the bacteria contained therein (collectively referred to as the microbiota) can modulate mood and behaviours, has an increasing body of supporting evidence, albeit largely derived from animal studies. The gut microbiota is a dynamic and diverse ecosystem and forms a symbiotic relationship with the host. Herein we describe the components of the gut microbiota and mechanisms by which it can influence neural development, complex behaviours and nociception. Furthermore, we propose the novel concept of a 'state of gut' rather than a state of mind, particularly in relation to functional bowel disorders. Finally, we address the exciting possibility that the gut microbiota may offer a novel area of therapeutic intervention across a diverse array of both affective and gastrointestinal disorders.

Irritable bowel syndrome: The evolution of multi-dimensional looking and multidisciplinary treatments

Irritable bowel syndrome (IBS) is common in the society. Among the putative pathogeneses, gut dysmotility results in pain and disturbed defecation. The latter is probably caused by the effect of abnormal gut water secretion. The interaction between abnormal gas accumulation, abdominal pain and bloating remains controversial. Visceral hypersensitivity and its modification along with the central transmission are the characteristics of IBS patients. The identification of biologic markers based on genetic polymorphisms is undetermined. Imbalanced gut microbiota may alter epithelial permeability to activate nociceptive sensory pathways which in turn lead to IBS. Certain food constituents may exacerbate bowel symptoms. The impact of adult and childhood abuses on IBS is underestimated. Using the concept of biopsychosocial dysfunction can integrate multidimensional pathogeneses. Antispasmodics plus stool consistency modifiers to treat the major symptoms and defecation are the first-line drug treatment. New drugs targeting receptors governing bowel motility, sensation and secretion can be considered, but clinicians must be aware of their potential serious side effects. Psychiatric drugs and modalities may be the final options for treating intractable subjects. Probiotics of multi-species preparations are safe and worth to be considered for the treatment. Antibiotics are promising but their long-term safety and effectiveness are unknown. Diet therapy including exclusion of certain food constituents is an economic measure. Using relatively safe complementary and alternative medicines (CAMs) may be optional to those patients who failed classical treatment. In conclusion, IBS is a heterogeneous disorder with multidimensional pathogeneses. Personalized medicines with multidisciplinary approaches using different classes of drugs, psychiatric measures, probiotics and antibiotics, dietary therapy, and finally CAMs, can be considered.

[Psychological alterations in patients with adult celiac disease]

Patients with recently-diagnosed adult celiac disease were evaluated with the Gastrointestinal Symptom rating Scale (GSRS) and Psychological General Well-Being Index (PGWBI) to evaluate their psychological alterations, the association between any alterations and gastrointestinal symptoms, and their outcome after starting a gluten-free diet. The patients underwent nutritional assessment and then started a gluten-free diet; they were reassessed 6 months later. Quantitative variables are expressed as the median and 25th-75th percentiles.

RESULTS

We included 21 patients, 17 women and 4 mena, with a mean age of 43 years (31-47). The results of histological analysis were compatible with Marsh I lesions in 6 patients, Marsh IIIa in 6 and Marsh IIIb in 9. At baseline, 8 patients showed severe psychological distress, 4 showed moderate distress and 9 showed no distress. The GSRS score was 34 (17-43) and the PGWBI was 64 (48-87), with a significant correlation between the 2 indexes (rho=-.58, P=.006). At 6 months, 3 patients had severe psychological distress, 5 had moderate distress, 9 showed no distress and 4 showed psychological well-being. The GSRS score at 6 months was 13 (8-17) and the PGWBI was 83 (68-95) (P<.05 compared with baseline data for the 3 indicators). The 6 axes of the PGWBI showed significant improvement. At 6 months, no correlation was found between the GSRS and PGWBI.

CONCLUSIONS

Patients with celiac disease have psychological alterations whose intensity is related to gastrointestinal symptoms. These symptoms improve after the start of a gluten-free diet.

Linaclotide

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. Subscribers to The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The February 2013 monograph topics are tofacitinib, cabozantinib, suvorexant, vortioxetine, and apremilast. The DUE/MUE is on tofacitinib.

Linaclotide

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. Subscribers to The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The February 2013 monograph topics are tofacitinib, cabozantinib, suvorexant, vortioxetine, and apremilast. The DUE/MUE is on tofacitinib.

Extra-intestinal and long term consequences of Giardia duodenalis infections

Giardiasis is the most common waterborne parasitic infection of the human intestine worldwide. The etiological agent, Giardia duodenalis (syn. G. intestinalis, G. lamblia), is a flagellated, binucleated protozoan parasite which infects a wide array of mammalian hosts. Human giardiasis is a true cosmopolitan pathogen, with highest prevalence in developing countries. Giardiasis can present with a broad range of clinical manifestations from asymptomatic, to acute or chronic diarrheal disease associated with abdominal pain and nausea. Most infections are self-limiting, although re-infection and chronic infection can occur. Recent evidence indicating that Giardia may cause chronic post-infectious gastrointestinal complications have made it a topic of intense research. The causes of the post-infectious clinical manifestations due to Giardia, even after complete elimination of the parasite, remain obscure. This review offers a state-of-the-art discussion on the long-term consequences of Giardia infections, from extra-intestinal manifestations, growth and cognitive deficiencies, to post-infectious irritable bowel syndrome. The discussion also sheds light on some of the novel mechanisms recently implicated in the production of these post-infectious manifestations.

Irritable bowel syndrome and migraine: bystanders or partners?

Irritable bowel syndrome (IBS) and migraine are distinct clinical disorders. Apart from the characteristics of chronic and recurrent pain in nature, these pain-related disorders apparently share many similarities. For example, IBS is female predominant with community prevalence about 5-10%, whereas that of migraine is 1-3% also showing female predominance. They are often associated with many somatic and psychiatric comorbidities in terms of fibromyaglia, chronic fatigue syndrome, interstitial cystitis, insomnia and depression etc., even the IBS subjects may have coexisted migraine with an estimated odds ratio of 2.66. They similarly reduce the quality of life of victims leading to the social, medical and economic burdens. Their pathogeneses have been somewhat addressed in relation to biopsychosocial dysfunction, heredity, genetic polymorphism, central/visceral hypersensitivity, somatic/cutaneous allodynia, neurolimbic pain network, gonadal hormones and abuses etc. Both disorders are diagnosed according to the symptomatically based criteria. Multidisciplinary managements such as receptor target new drugs, melantonin, antispasmodics, and psychological drugs and measures, complementary and alternatives etc. are recommended to treat them although the used agents may not be necessarily the same. Finally, the prognosis of IBS is pretty good, whereas that of migraine is less fair since suicide attempt and stroke are at risk. In conclusion, both distinct chronic pain disorders to share many similarities among various aspects probably suggest that they may locate within the same spectrum of a pain-centered disorder such as central sensitization syndromes. The true pathogenesis to involve these disorders remains to be clarified in the future.

Probiotics in the management of functional bowel disorders: promise fulfilled?

Irritable bowel syndrome (IBS) and chronic constipation (CC) are common problems worldwide and are associated with significant impact on activities of daily living and quality of life. Recent interest, in IBS in particular, has focused on the potential roles of the microbiota and its interaction with the host's immune system. Recently, high-quality clinical trials have been performed on prebiotics and probiotics in IBS or CC. Although strategies that seek to modify the microbiota, such as the use of probiotics, offer much promise in IBS and CC, more high-quality trials and, studies of longer duration are required.