New insights into the pathogenesis and pathophysiology of irritable bowel syndrome

Characteristics of ginsenoside Rd-induced effects on rat intestinal contractility with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a very common refractory disease. Its exact pathophysiological mechanism is still unclear. Despite the availability of plentiful drugs to control IBS, most patients do not respond well. Ginsenoside Rd is one of the major active components of Panax ginseng, which has been verified to produce various pharmacological actions. However, the role of ginsenoside Rd in modulating smooth muscle contractility is still undefined. The aim of this study is to investigate the effects of ginsenoside Rd on intestinal contractility and related mechanisms in IBS.

Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery

BACKGROUND

Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD.

RESULTS

The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota.

CONCLUSIONS

Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice. Video Abstract.

Faecalibacterium prausnitzii in Differentiated Thyroid Cancer Patients Treated with Radioiodine

BACKGROUND

Faecalibacterium prausnitzii, one of the most important bacteria of the human gut microbiota, produces butyrate (a short-chain fatty acid). Short-chain fatty acids are known to influence thyroid physiology and thyroid cancer's response to treatment. We aimed to analyze the relative abundance of Faecalibacterium prausnitzii on the gut microbiota of differentiated thyroid cancer patients compared to controls and its variation after radioiodine therapy (RAIT).

METHODS

Fecal samples were collected from 37 patients diagnosed with differentiated thyroid cancer before and after radioiodine therapy and from 10 volunteers. The abundance of F. prausnitzii was determined using shotgun metagenomics.

RESULTS

Our study found that the relative abundance of F. prausnitzii is significantly reduced in thyroid cancer patients compared to volunteers. We also found that there was a mixed response to RAIT, with an increase in the relative and absolute abundances of this bacterium in most patients.

CONCLUSIONS

Our study confirms that thyroid cancer patients present a dysbiotic gut microbiota, with a reduction in F. prausnitzii's relative abundance. In our study, radioiodine did not negatively affect F. prausnitzii, quite the opposite, suggesting that this bacterium might play a role in resolving radiation aggression issues.

Gut-Brain Axis Perspective on Negative Symptoms and Their Neighbors in Early Adolescence: Can We Move Care Upstream?

The current study investigated symptom network patterns in adolescents from a gut-brain-axis (GBA) biopsychosocial perspective. Our secondary analysis of data from the Adolescent Brain Cognitive Development Study assessed symptom relationships using network analysis to provide information about multivariate structural dependencies among 41 signs and symptoms. Cross-sectional EBICglasso symptom networks were evaluated to assess patterns associated with anhedonia and depressed mood. Significant differences were identified between symptom neighbors of anhedonia compared with depressed mood based on stratification by age. The GBA perspective revealed several symptom neighbors that could expand clinical assessment, diagnosing criteria, education, and interventions for adolescents at risk for, or with, anhedonia or depressed mood. Results speak to the unique impact of symptoms on health that are not interchangeable with other symptoms and do not have equal effects. Mental health nurses should consider a holistic and proactive precision health approach to improving health and well-being through evidence-based assessment of symptom associations. [Journal of Psychosocial Nursing and Mental Health Services, xx(xx), xx-xx.].

The Potential Role of Human Milk Oligosaccharides in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is the most common gastrointestinal (GI) disorder in Western populations and therefore a major public health/economic concern. However, despite extensive research, psychological and physiological factors that contribute to the aetiology of IBS remain poorly understood. Consequently, clinical management of IBS is reduced to symptom management through various suboptimal options. Recent evidence has suggested human milk oligosaccharides (HMOs) as a potential therapeutic option for IBS. Here, we review literature concerning the role of HMOs in IBS, including data from intervention and in vitro trials. HMO supplementation shows promising results in altering the gut microbiota and improving IBS symptoms, for instance by stimulating bifidobacteria. Further research in adults is required into HMO mechanisms, to confirm the preliminary results available to date and recommendations of HMO use in IBS.

A Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effects of Multi-Strain Synbiotic in Patients with Functional Diarrhea and High Fecal Calprotectin Levels: A Pilot Study

Synbiotics, including probiotics and prebiotics, are useful for patients with functional bowel disorders. However, which synbiotics are beneficial for patients with which diseases, especially those with functional diarrhea (FDr) with high fecal calprotectin levels, is currently unknown. FDr is an extension of irritable bowel syndrome with diarrhea (IBS-D). Although fewer studies have been conducted on FDr compared to IBS-D, its importance is increasing as its prevalence increases. The aim of this study was to evaluate the effects of a synbiotic containing a mixture of Lactobacillus and Bifidobacterium and its substrate, fructooligosaccharide, on bowel symptoms, fecal calprotectin levels, fecal microbiota, and safety in FDr patients with high fecal calprotectin levels. Forty patients were randomly assigned to either a synbiotic group or a placebo group. A total of 20 subjects in the synbiotic group and 19 subjects in the placebo group completed the study (8 weeks). Changes in FDr symptoms, fecal calprotectin levels, and gut microbiota were assessed during the intervention period. At 4 and 8 weeks, the number of bowel movements tended to increase in the synbiotic group, with a significant increase in the number of formed stools rather than loose stools (p < 0.05). Bowel movement satisfaction was significantly increased in the synbiotic group, but not in the placebo group. Intestinal flora analysis revealed that Lactobacillales at the order level was increased only in the synbiotic group at the end of the intervention. In contrast, at week 8 of the intervention, log-transformed fecal calprotectin levels were significantly decreased in the synbiotic group, although the change was not significantly different from that of the placebo group. These findings suggest that the intake of a multi-strain-containing synbiotic for 8 weeks could improve gut symptoms and the intestinal microenvironment of FDr patients with high fecal calprotectin levels.

The Impact of Zinc and Zinc Homeostasis on the Intestinal Mucosal Barrier and Intestinal Diseases

Zinc is an essential trace element for living organisms, and zinc homeostasis is essential for the maintenance of the normal physiological functions of cells and organisms. The intestine is the main location for zinc absorption and excretion, while zinc and zinc homeostasis is also of great significance to the structure and function of the intestinal mucosal barrier. Zinc excess or deficiency and zinc homeostatic imbalance are all associated with many intestinal diseases, such as IBD (inflammatory bowel disease), IBS (irritable bowel syndrome), and CRC (colorectal cancer). In this review, we describe the role of zinc and zinc homeostasis in the intestinal mucosal barrier and the relevance of zinc homeostasis to gastrointestinal diseases.

Colonic mucosal eosinophilia and immunohistochemical expression of COX-2 and NF-kB in patients with irritable bowel syndrome

BACKGROUND

There is growing evidence that eosinophilic infiltration can release mediators which are harmful to the intestinal epithelium in patients with irritable bowel syndrome (IBS). Although cyclooxygenase 2 (COX-2) and nuclear factor-kappa beta (NF-kB) expression had been previously reported to increase in many inflammatory conditions, there is a paucity in data investigating their expressions in IBS. Our aim was to evaluate colonic mucosal eosinophilia and immunohistochemical expression of COX-2 and NF-kB in patients with irritable bowel syndrome.

METHODS

A total of 80 patients who met the inclusion criteria of IBS based on Rome IV symptoms questionnaire were subjected to abdominal ultrasound, laboratory investigations, serum immunoglobulin E (IgE) level assessment and colonoscopic examination. Immunohistochemistry was performed to detect COX-2 and NF-kB expression in colonic biopsies obtained from IBS patients.

RESULTS

Histopathological examination showed that 60 colonic biopsy specimens (75%) showed few mixed inflammatory cells ≤3 cells/ HPF, 12 biopsy specimens (15%) showed eosinophilic infiltration ≥25 eosinophils/HPF and 8 biopsy specimens (10%) showed severe lymphocytic infiltration and aggregation. Colonic eosinophilic infiltrate was significantly higher among patients presented with IBS-D subtype. Serum IgE was significantly higher among patients with colonic eosinophilic infiltrate than the others. In IBS-D patients, colonic mucosa showed positive expression of COX-2 and NF-kB in 52.1% and 81.25% of cases, respectively.

CONCLUSION

Patients with IBS -particularly IBS-D subtype- should undergo colonoscopy and biopsy to exclude underlying inflammatory pathology. Moreover, patients with positive COX-2 and NF-kB need further evaluation and follow-up.

Causal Relationship between Physiological and Pathological Processes in the Brain and in the Gastrointestinal Tract: The Brain-Intestine Axis

The brain and gastrointestinal tract are the most important organs responsible for detecting, transmitting, integrating, and responding to signals coming from the internal and external environment. A bidirectional system of neurohumoral communication (the "intestine-brain" axis) combines the activity of the intestine and brain (or brain and intestine) of a person. It affects human development and behavior. This paper analyzes the literature data on the existence of a relationship between the central and enteral nervous systems. Based on data on the number of neurons in the enteral nervous system (approximately 250 million nerve cells), the concept of a "second brain" in the intestine has been proposed in foreign literature, which, by its influence on the brain, can have a more powerful influence than the spinal cord (approximately 10 million neurons) with its autonomic nervous system. However, it turned out that Russian scientists, academicians of the Academy of Sciences of the Soviet Union I.P. Pavlov, K.M. Bykov, and A.M. Ugolev, analyzed cortical-visceral relationships in the 20th century and wrote about the existence of a connection between the central and enteral nervous systems. One of the urgent problems of modern physiology, pathophysiology, biophysics, biochemistry, and medicine is to clarify the causal relationship between the central and enteral nervous systems, as well as between neurological, mental, and gastrointestinal diseases in order to combine the efforts of specialists of various medical and biological profiles to solve urgent medical problems.

Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort

(1) Background: Specific foods, and more particularly, fermentable oligo-, di-, and mono-saccharides and polyols (FODMAPs) are often considered as triggers of digestive symptoms in Irritable Bowel Syndrome (IBS). Our aim was to study FODMAP consumption in controls and IBS participants in a large French population-based cohort; (2) Methods: Participants from the NutriNet-Santé cohort study completed the Rome IV and IBS-SSS questionnaire in a cross sectional study. Among them, 27,949 eligible participants had previously completed three 24-h recalls as well as anthropometrics, socio-demographical and lifestyle data. Total FODMAP intake (in g/day) was computed using a specific composition table. The association between FODMAPs and IBS was estimated through multivariable logistic regression models; (3) Results: Included participants were mainly women (75.4%) and the mean age was 43.4 ± 14.1 years. FODMAPs accounted for a mean daily intake of 19.4 ± 9.5 g/day. Overall 1295 participants (4.6%) were identified with an IBS. After adjusting for confounding factors, IBS participants had lower intakes in FODMAPs than non-IBS ones (aOR: 0.88, 95% CI: 0.82–0.95, p-value: 0.001). IBS severity was associated with more frequent low FODMAP intakes (<9 g/day); (4) Conclusions: Participants tended to consume 19 g of FODMAPs per day, but slightly less for IBS participants than for controls. In IBS participants, higher severity was associated with lower intakes.

Model Integration: Can Understanding Biopsychosocial Gut-Brain Axis Mechanistic Pathways Improve our Clinical Reasoning in Primary Care?

Introduction

Most NPs practice in primary care settings. Cognitive tools to inform and advance NP understanding of biopsychosocial mechanisms can support early recognition, interdisciplinary collaboration, interventions, and prevention of negative outcomes.

Theory and Methods

We describe the development of a model to support NP consideration of gut-brain axis (GBA) evidence-based pathways, contributing variables, and related health outcomes.

Results

The model's outcomes are factors associated with homeostasis or disruption of biological, psychological, and social systems.

Discussion/conclusion

This cognitive tool aims to support NP awareness of multi-domain GBA relationships to consider with differential diagnoses and clinical treatment of the "whole body system".

Wei Chang An pill regulates gastrointestinal motility in a bidirectional manner

CONTEXT

Wei Chang An (WCA) is a commercial prescription developed for the coordination of gastrointestinal movement.

OBJECTIVE

To investigate the role of WCA in the regulation of diarrhoea and constipation in rats.

MATERIAL AND METHODS

The diarrhoea and constipation models were prepared by gavage of Folium senna and diphenoxylate hydrochloride. Rats were randomized equally (n = 6) into the normal group given saline daily, the positive group given Pinaverium Bromide (13.5 mg/kg) or Sennoside A (0.1 mg/kg) and three WCA-treated groups (22, 44, and 88 mg/kg) by gavage daily for 7 consecutive days. The effects of WCA were assessed by a series of faecal symptoms and histopathology. Gastrointestinal parameters were determined by ELISA. The effect of WCA on gastrointestinal tissues was evaluated by strip assay. Expression of ROCK-1 and MLCK was measured by RT-PCR and Western blotting.

RESULTS

Data from Bristol stool form scale, diarrhoea index, visceral sensitivity, defaecation time, and intestinal propulsive rate showed that WCA protected rats against diarrhoea and constipation (p < 0.01). The up-regulation of Substance P and 5-hydroxytryptamine in diarrhoea rats and down-regulation of Substance P and vasoactive intestinal polypeptide in constipation rats were inhibited by WCA (p < 0.05). WCA stimulated the gastrointestinal strip contractions but inhibited ACh-induced contractions (p < 0.01). The decreased ROCK-1 and MLCK expression in diarrhoea rats and increased in constipation rats were suppressed by WCA (p < 0.01).

CONCLUSIONS

WCA has both antidiarrhea and anti-constipation effects, suggesting its bidirectional role in gastrointestinal modulation, and providing evidence of WCA for irritable bowel syndrome treatment.

Does Alzheimer's disease stem in the gastrointestinal system?

Over the last decades, our knowledge of the key pathogenic mechanisms of Alzheimer's disease (AD) has dramatically improved. Regarding the limitation of current therapeutic strategies for the treatment of multifactorial diseases, such as AD, to be translated into the clinic, there is a growing trend in research to identify risk factors associated with the onset and progression of AD. Here, we review the current literature with a focus on the relationship between gastrointestinal (GI)/liver diseases during the lifespan and the incidence of AD, and discuss the possible mechanisms underlying the link between the diseases. We also aim to review studies evaluating the possible link between the chronic use of the most common GI medications and the future risk of AD development.

Adherence to Dietary Approaches to Stop Hypertension Eating Plan and Prevalence of Irritable Bowel Syndrome in Adults

Background/Aims

Despite huge evidence on the link between adherence to dietary approaches to stop hypertension (DASH) eating pattern and several metabolic abnormalities, the association of this diet with irritable bowel syndrome (IBS) has not been investigated so far. We aim to examine the association between adherence to the DASH diet and prevalence of IBS symptoms and subtypes in adults.

Methods

This cross-sectional study was done among 3362 adult people in Isfahan, Iran. Usual dietary intakes were assessed using a validated 106-item dish-based semi-quantitative food frequency questionnaire. To investigate participants’ adherence to DASH-style diet, we created DASH score based on 8 main foods and nutrients emphasized or minimized in the DASH diet. Participants were classified into 3 categories according to their DASH-style diet scores. A validated modified Persian version of the Rome III questionnaire was applied for assessment of IBS.

Results

Totally, 22.2% of study participants were affected by IBS. After adjustment for potential confounding factors, we found that participants in the highest tertile of DASH score had lower odds of IBS (OR, 0.65; 95% CI, 0.50-0.83) compared with those in the lowest tertile. The same findings were also reached for IBS with constipation (OR for the highest vs the lowest tertile of DASH-style diet = 0.56; 95% CI, 0.38-0.85). No significant association was seen between adherence to DASH-style diet and IBS with diarrhea (OR, 1.31; 95% CI, 0.83-2.06).

Conclusions

We found a significant inverse association between adherence to DASH dietary pattern and odds of IBS and IBS with constipation. Further prospective studies are required to confirm these findings.

Study on the clinical mechanism of Tong-Xie-An-Chang Decoction in the treatment of diarrheal irritable bowel syndrome based on single-cell sequencing technology

BACKGROUND

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a kind of functional gastrointestinal disorder with obscure pathogenesis, and exploration about differential gene expression and cell heterogeneity of T lymphocytes in peripheral blood in IBS-D patients still remains unknown. Clinicians tend to use symptomatic treatment, but the efficacy is unstable and symptoms are prone to relapse. Traditional Chinese Medicine (TCM) is used frequently in IBS-D with stable and lower adverse effects. Tong-Xie-An-Chang Decoction (TXACD) has been proven to be effective in the treatment of IBS-D. However, the underlying therapeutic mechanism remains unclear. This trial aims to evaluate the clinical efficacy and safety of TXACD in IBS-D and elucidate the gene-level mechanism of IBS-D and therapeutic targets of TXACD based on single-cell sequencing technology.

METHODS/DESIGN

This is a randomized controlled, double-blind, double-simulation clinical trial in which 72 eligible participants with IBS-D and TCM syndrome of liver depression and spleen deficiency will be randomly allocated in the ratio of 1:1 to two groups: the experimental group and the control group. The experimental group receives Tong-Xie-An-Chang Decoction (TXACD) and Pinaverium bromide tablets placebo; the control group receives pinaverium bromide tablets and TXACD placebo. Each group will be treated for 4 weeks. The primary outcome: the rate of IBS-Symptom Severity Score (IBS-SSS). The secondary outcomes: TCM syndrome score, adequate relief and IBS-Quality of Life Questionnaire (IBS-QOL). Mechanistic outcome is the single-cell sequencing profiling of the T lymphocytes in peripheral blood from IBS-D participants before and after the treatment and healthy individuals.

DISCUSSION

This trial will prove the efficacy and safety of TXACD with high-quality evidence and provide a comprehensive perspective on the molecular mechanism of IBS-D by single-cell sequencing profiling, which makes us pinpoint specific biomarkers of IBS-D and therapeutic targets of TXACD.

The Infant-Derived Bifidobacterium bifidum Strain CNCM I-4319 Strengthens Gut Functionality

Bifidobacteria are among the first colonisers of the gastrointestinal tract of breast-fed newborns due to, among other things, their ability to metabolise oligosaccharides naturally occurring in human milk. The presence of bifidobacteria in the infant gut has been shown to promote intestinal health and homeostasis as well as to preserve a functional gut barrier, thus positively influencing host health and well-being. Among human-associated gut commensals, Bifidobacterium bifidum has been described as the only species capable of the extracellular degradation of both mucin-type glycans and HMOs, thereby giving this species a special role as a commensal gut forager of both host and diet-derived glycans. In the present study, we assess the possible beneficial properties and probiotic potential of B. bifidum strain CNCM I-4319. In silico genome analysis and growth experiments confirmed the expected ability of this strain to consume HMOs and mucin. By employing various animal models, we were also able to assess the ability of B. bifidum CNCM I-4319 to preserve gut integrity and functionality from stress-induced and inflammatory damage, thereby enforcing its potential as an effective probiotic strain.

Associations among neurophysiology measures in irritable bowel syndrome (IBS) and their relevance for IBS symptoms

Abnormal gut-brain interactions are common in irritable bowel syndrome (IBS), but the associations between neurophysiological measures and their relation to gastrointestinal (GI) symptoms are poorly understood. Our aim was to explore these relationships and define the most relevant neurophysiology measures for GI symptom severity in IBS. IBS patients underwent small intestinal motility (manometry; fasted and fed contraction frequency, phase III time) and secretion (transmural potential difference), rectal sensorimotor (barostat; sensory thresholds, tone response, compliance), autonomic nervous system (baroreceptor sensitivity and effectiveness), and colonic motor function (transit time) examinations. GI symptom severity (GSRS-IBS), and anxiety and depression (HAD) as a proxy measure of central nervous system (CNS) dysfunction, were assessed. In total 281 IBS patients (Rome II criteria) were included (74% females, median age 36 [interquartile range 28-50] years). Significant correlations between neurophysiology measures were stronger within, rather than between, different neurophysiological examinations. The strongest neurophysiology-symptom correlations occurred between a combination of CNS and visceral sensitivity parameters, and GSRS-IBS total score and pain domain (ρ = 0.40, p < 0.001, and ρ = 0.38, p < 0.001). Associations between GI symptoms in IBS and individual and combinations of neurophysiological factors occurred, primarily in CNS and visceral sensitivity measures, providing new insights into the clinical presentation of IBS.

Clinical efficacy and safety of ketotifen in treating irritable bowel syndrome with diarrhea

OBJECTIVE

The aim of the study was to investigate the clinical efficacy and safety of ketotifen for the treatment of irritable bowel syndrome with diarrhea (IBS-D).

METHODS

A total of 108 enrolled IBS-D patients were randomly divided into a ketotifen group (n = 55) and a control (placebo) group (n = 53). The patients in the ketotifen group received ketotifen tablets (1 mg, oral) two times daily; patients in the control group received oral placebo for 8 weeks. Before and after 8 weeks of treatment, gastrointestinal symptoms, anorectal sensory function and the number and activity status of mast cells were assessed for both groups.

RESULTS

(1) The overall effective rate of gastrointestinal symptom improvement in the ketotifen group was significantly higher than that in the control group (76.4 vs. 37.7%, P < 0.001). (2) First sensation, defecation urgency and discomfort/pain threshold in the ketotifen group improved significantly after treatment (P < 0.05); no significant changes were observed in the control group (P > 0.05). (3) In the ketotifen group, the number of mast cells in the terminal ileum decreased, and the percentages of degranulated mast cells in the sigmoid colon, ascending colon and terminal ileum decreased significantly after treatment compared with before treatment; these differences were statistically significant (P < 0.01). In the control group, the number of mast cells and the percentages of degranulated mast cells in various sites did not change significantly before and after treatment (P > 0.05). (4) Six patients (10.9%) in the ketotifen group experienced drowsiness and fatigue, but the symptoms disappeared after 1 week of treatment.

CONCLUSION

Ketotifen significantly alleviated gastrointestinal symptoms and improved visceral hypersensitivity in patients with IBS-D. The therapeutic effect of ketotifen is related to a reduced number and decreased activity of mast cells in the intestinal mucosa, especially in the terminal ileum.

An Intervention for Person-Centered Support in Irritable Bowel Syndrome: Development and Pilot Study

Irritable bowel syndrome is a common and often chronic functional bowel disorder that can cause severe disruption of daily functioning in those affected, with subsequent high healthcare utilization and work absenteeism. Nurses represent an underutilized group in the current management of irritable bowel syndrome. The aim of this study was to systematically develop a person-centered support intervention in irritable bowel syndrome and evaluate this in a pilot study. The development followed the revised framework for complex interventions from the Medical Research Council and involved literature reviews and multiprofessional expert groups. The intervention was then tested in a pilot study including 17 patients and evaluated through validated questionnaires measuring irritable bowel syndrome symptom severity, gastrointestinal-specific anxiety, and self-efficacy as well as through interviews. There was a significant improvement in irritable bowel syndrome symptom severity between baseline and follow-up, but not for self-efficacy or gastrointestinal-specific anxiety. The patients' perceptions of participating in the intervention were positive and induced a learning process; they were able to form a supportive relationship with the nurse and their ability to self-manage improved. The promising results from this small pilot study in terms of feasibility, potential efficacy, and the patients' positive feedback make this intervention a suitable candidate for a larger controlled trial.

Relevance of Sex and Subtype in Patients With IBS: An Exploratory Study of Gene Expression

BACKGROUND

Psychological state, stress level, and gastrointestinal function are intricately related and relevant to symptom exacerbation in patients with irritable bowel syndrome (IBS), but genetic contributors to this brain-gut connection are not fully understood. The purpose of this exploratory study was to compare gene expression in participants with IBS to that of healthy controls (HC) and to examine patterns of expression in participants with IBS by sex and IBS subtype.

METHOD

Participants were recruited to an ongoing protocol at the National Institutes of Health. Differences in demographic and clinical characteristics were assessed using descriptive statistics and Mann-Whitney U tests. Expression levels of 84 genes were evaluated in peripheral whole blood using Custom RT2 Profiler polymerase chain reaction (PCR) Arrays, and data analysis was performed through GeneGlobe Data Analysis Center.

RESULTS

Participants with IBS (n = 27) reported greater levels of perceived stress (p = .037) and differed in expression values of ±2 for the genes ADIPOR1, ADIPOR2, CNR2, COMT, OXTR, and PPARA compared to HC (n = 43). Further analyses by sex and IBS subtype revealed differential patterns of gene expression related to the endocannabinoid system, cytokines, stress, and sex steroid hormones.

CONCLUSIONS

Diverse yet interconnected processes such as metabolism, inflammation, immunity, social behavior, and pain are associated with differences in gene expression between participants with IBS and HC. These findings lend support for genomic associations with the brain-gut connection in patients with IBS and highlight the relevance of sex and IBS subtype in performing such analyses.

The Dietary Management of Patients with Irritable Bowel Syndrome: A Narrative Review of the Existing and Emerging Evidence

Even though irritable bowel syndrome (IBS) has been known for more than 150 years, it still remains one of the research challenges of the 21st century. According to the current diagnostic Rome IV criteria, IBS is characterized by abdominal pain associated with defecation and/or a change in bowel habit, in the absence of detectable organic causes. Symptoms interfere with the daily life of patients, reduce health-related quality of life and lower the work productivity. Despite the high prevalence of approximately 10%, its pathophysiology is only partly understood and seems multifactorial. However, many patients report symptoms to be meal-related and certain ingested foods may generate an exaggerated gastrointestinal response. Patients tend to avoid and even exclude certain food products to relieve their symptoms, which could affect nutritional quality. We performed a narrative paper review of the existing and emerging evidence regarding dietary management of IBS patients, with the aim to enhance our understanding of how to move towards an individualized dietary approach for IBS patients in the near future.

Identification of an intestinal microbiota signature associated with hospitalized patients with diarrhea

As an important global health challenge, diarrhea kills nearly two million people each year. Postinfectious irritable bowel syndrome (IBS) usually manifests itself as the diarrhea-predominant subtype. Small intestinal bacterial overgrowth has been observed more frequently in patients with IBS compared to healthy controls. However, the pathophysiology of IBS is not fully understood, and based on recent evidences, altered gut microbiota is involved in the pathogenesis of IBS. Therefore, we aimed to compare the microbiome in hospitalized patients with diarrhea and healthy individuals. Thirty patients and 10 healthy controls were included into this case-control study. Microbial count was performed using quantitative real-time polymerase chain reaction method using bacterial 16S rRNA gene. Clostridium cluster IV and Bacteroides were significantly more frequent in the patients compared with the healthy individuals (p = 0.02 and 0.023, respectively). However, the quantity of Enterococcus and Bifidobacterium groups were significantly higher in healthy controls than in diarrheal group (p = 0.000076 and 0.001, respectively). The results showed that the number of bacteria in all bacterial groups was significantly different between healthy individuals and diabetic group, whereas the difference between the healthy group and IBS was not significant for Bifidobacterium group. The findings of this study outlined the relationship between diarrhea, IBS, and diabetes disease and bacterial composition. It could be concluded that modifying the bacterial composition by probiotics can be helpful in the control and management of the mentioned disease.

Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis

BACKGROUND AND PURPOSE

Irritable bowel syndrome (IBS) affects 10%-20% of the adult population and is characterized by abdominal symptoms without relevant organic disease. There are numerous clinical trials available investigating the relationship between IBS, lactose maldigestion (LM), and lactose intolerance (LI), but there have been no meta-analyses on this topic yet. We aimed to assess the prevalence of LM, objective and subjective (self-reported) LI in IBS patients compared to healthy controls (HC) without IBS.

METHODS

A systematic literature search was conducted up to 24 April 2018 in PubMed, Embase, and Cochrane Library. Adult IBS patients had to be diagnosed according to the Rome criteria or other well-defined criteria system. We enrolled controlled studies including healthy adult participants without IBS, as control group. Odds ratios with 95% confidence intervals were calculated.

KEY RESULTS

Altogether 14 articles were suitable for statistical analyses. IBS patients reported themselves significantly more frequently lactose intolerant than HCs (odds ratio [OR] = 3.499; 95% confidence interval [CI] = 1.622-7.551). Generally, there was no significant difference in the prevalence of LM based on ingested lactose dose (OR = 1.122; 95% CI = 0.929-1.356) and test type (OR = 1.156; 95% CI = 0.985-1.356). However, significantly more IBS patients had objective LI (OR = 2.521; 95% CI = 1.280-4.965).

CONCLUSIONS AND INFERENCES

Lactose intolerance, but not LM is more frequent among patients with IBS compared to HCs. According to our results, IBS among other functional bowel disorders is a possible contributing factor of LI in people with LM.

Translocator protein 18kDa antagonist ameliorates stress-induced stool abnormality and abdominal pain in rodent stress models

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by abdominal pain and abnormal bowel habits, both of which are exacerbated by psychological stress. The translocator protein 18kDa (TSPO) is a marker of reactive gliosis in a number of central nervous system (CNS) diseases and responsible for many cellular functions, including neurosteroidogenesis. Although it has been reported that psychological stress disturbs neurosteroids levels, the pathophysiological relevance of TSPO in IBS is poorly understood.

METHODS

We examined the effects of a TSPO antagonist, ONO-2952, on stress-induced stool abnormality and abdominal pain in rats, and on anxiety-related behavior induced by cholecystokinin.

KEY RESULTS

Oral administration of ONO-2952 attenuated stress-induced defecation and rectal hyperalgesia in rats with an efficacy equivalent to that of a 5-HT₃ receptor antagonist. In addition, ONO-2952 suppressed cholecystokinin-induced anxiety-like behavior with an efficacy equivalent to that of psychotropic drugs. On the other hand, ONO-2952 did not affect spontaneous defecation, gastrointestinal transit, visceral nociceptive threshold, and neurosteroid production in non-stressed rats even at a dose 10 times higher than its effective dose in the stress models.

CONCLUSIONS AND INFERENCES

These results suggest that TSPO antagonism results in antistress action, and that ONO-2952 is a promising candidate for IBS without side effects associated with current treatment.

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

AIM

To study the role of microbial metabolites in the modulation of biochemical and physiological processes in irritable bowel syndrome (IBS).

METHODS

In 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.

RESULTS

WAS 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.

CONCLUSION

The 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.

Endoscopic muscle biopsy sampling of the duodenum and rectum: a pilot survival study in a porcine model to detect myenteric neurons

BACKGROUND AND AIMS

Small bowel and colorectal muscle biopsy sampling requires a surgical approach. Advancing our understanding of the pathophysiology of motility disorders, such as functional bowel disorders, intestinal pseudo-obstruction, and slow-transit constipation, is hindered by our inability to noninvasively obtain muscularis propria (MP) for evaluation of multiple cell types, including myenteric neurons. The aims of this study were to determine (1) technical feasibility, reproducibility, and safety of performing duodenal endoscopic muscle biopsy sampling (dEMB) and rectal endoscopic muscle biopsy sampling (rEMB) using a clip-assist technique and (2) the presence of myenteric neurons in tissue samples.

METHODS

Five 40-kg pigs were studied. Each animal underwent a dEMB and rEMB procedure. dEMB was performed using a single resection clip-assist technique. An over-the-scope clip was advanced to the duodenum. Tissue was suctioned into the cap and the clip deployed. The pseudopolyp of the duodenal wall created was then resected using snare electrocautery. rEMB was performed using a double resection clip-assist technique. EMR was initially performed to uncover the underlying MP using a band ligation technique. An over-the-scope clip was then advanced to the exposed MP. The MP was retracted and suctioned into the cap and the clip deployed. The pseudopolyp of the MP was resected using snare electrocautery. An antibody to protein gene product 9.5 was used to determine the presence of myenteric neurons in the samples. Animals were kept alive for 2 weeks, at which time an upper endoscopy and necropsy were performed.

RESULTS

dEMB and rEMB were successfully performed in all animals with no procedural adverse events using this "no hole" (close then cut) approach. Mean procedure times for dEMB and rEMB were 23.7 ± 2.5 minutes and 13.25 ± 2.8 minutes, respectively. Mean length of resected full-thickness duodenal wall was 13.25 ± 4.3 mm and rectal MP was 12.5 ± 1.7 mm. Hematoxylin and eosin stain and antibody to protein gene product 9.5 confirmed the presence of MP with inner circular, outer longitudinal, and intermuscular layers, including myenteric neurons, in all samples. Clinical course was uneventful in all animals. Repeat upper endoscopy at 2 weeks showed well-healed dEMB sites. Necropsy in all animals showed no perforation, fluid collection, or abscess at the dEMB and rEMB sites.

CONCLUSIONS

Based on this preclinical study, dEMB and rEMB appear to be technically feasible, reproducible, and safe. Sufficient MP tissue was obtained to identify myenteric neurons. These promising results are a step toward successful and safe implementation of these techniques into clinical practice for tissue diagnosis of muscle-based pathologies.

Understanding the Gut Microbiota in Inflammatory and Functional Gastrointestinal Diseases

OBJECTIVE

During the last decade, experimental and observational studies have shown that patients with inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) may have an altered intestinal microbial composition compared with healthy individuals. However, no uniform microbial signature has as yet been detected for either IBD or IBS. This review summarizes the current knowledge of microbial dysbiosis and its potential relationship to the pathophysiology in IBD and IBS.

METHODS

A selective review was conducted to summarize the current knowledge of gut microbiota in the pathophysiology of IBD and IBS.

RESULTS

Experimental and observational studies provide good evidence for intestinal microbial dysbiosis in subgroups of IBD and IBS. Still, no uniform disease pattern has been detected. This is most likely due to the heterogeneous nature of IBD and IBS, in combination with the effects of intrinsic and extrinsic factors. Such intrinsic factors include genetics, the gastrointestinal environment, and the host immune system, whereas extrinsic factors include early life diet, breastfeeding, and method of infant delivery.

CONCLUSIONS

Recent and ongoing work to define microbial dysbiosis in IBD and IBS shows promise, but future well-designed studies with well-characterized study individuals are needed. It is likely that the microbial dysbiosis in IBD and IBS is dependent on the natural disease course of IBD and symptom pattern in IBS. Therefore, assessment of the entire microbiota along the gastrointestinal tract, in relationship to confounding factors, symptom fluctuations, and other pathophysiological factors, is needed for further understanding of the etiology of these common diseases.

Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies

Background

Irritable bowel syndrome (IBS) and functional digestive tract disorders, e.g. functional bloating, carbohydrate maldigestion and intolerances, are very common disorders frequently causing significant symptoms that challenge health care systems. A low Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP) diet is one of the possible therapeutic approaches for decreasing abdominal symptoms and improving quality of life.

Objectives

We aimed to meta-analyze data on the therapeutic effect of a low-FODMAP diet on symptoms of IBS and quality of life and compare its effectiveness to a regular, standard IBS diet with high FODMAP content, using a common scoring system, the IBS Symptom Severity Score (IBS-SSS).

Methods

A systematic literature search was conducted in PubMed, EMBASE and the Cochrane Library as well as in the references in a recent meta-analysis. Adult patients diagnosed with IBS according to the Rome II, Rome III, Rome IV or NICE criteria were included in the analysis.

Statistical methods

Mean differences with 95% confidence intervals were calculated from studies that contained means, standard deviation (SD) or mean differences and SD of differences and p-values. A random effect model was used because of the heterogeneity (Q test (χ2) and I² indicator). A p-value of less than 0.05 was chosen to indicate a significant difference.

Results

The literature search yielded 902 publications, but only 10 were eligible for our meta-analysis. Both regular and low-FODMAP diets proved to be effective in IBS, but post-diet IBS-SSS values were significantly lower (p = 0.002) in the low-FODMAP group. The low-FODMAP diet showed a correlation with the improvement of general symptoms (by IBS-SSS) in patients with IBS.

Conclusions

This meta-analysis provides high-grade evidence of an improved general symptom score among patients with irritable bowel syndrome who have maintained a low-FODMAP diet compared to those on a traditional IBS diet, therefore showing its superiority to regular IBS dietary therapy. These data suggest that a low-FODMAP diet with dietitian control can be a candidate for first-line therapeutic modality in IBS. Because of a lack of data, well-planned randomized controlled studies are needed to ascertain the correlation between improvement of separate key IBS symptoms and the effect of a low-FODMAP diet.

Effects of a Low FODMAP Diet and Specific Carbohydrate Diet on Symptoms and Nutritional Adequacy of Patients with Irritable Bowel Syndrome: Preliminary Results of a Single-blinded Randomized Trial

BACKGROUND AND OBJECTIVES

IBS is the most common functional disease of the low gastrointestinal tract. Recently, the interest towards a diet approach has increased, for example, a diet with low content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs). The aim of the present study is to evaluate the efficacy of a low FODMAP diet and a specific carbohydrate diet (SCD) conducted for 3 months on symptoms and to evaluate the deficiencies of vitamin D and folic acid in patients affected by IBS, matching the Rome IV criteria.

METHODS

We evaluated 73 patients divided into 2 groups: one submitted to low FODMAP diet and one to SCD, for 3 months. Patients were assigned to one of the 2 groups randomly and blinded. All the patients filled a visual analogue scale (VAS) to evaluate the severity of symptoms and a diary to evaluate the number of days with symptoms, and this was repeated after 3 months. Final evaluation was made by a blinded investigator.

RESULTS

In the end, the patients with low FODMAP diet had a significant improvement in bloating and distension (P = 0.000); the group with SCD instead had a low but not a significant improvement. One way ANOVA showed comparable severity of symptoms in the 2 groups pre-diet (P = 0.215), but a difference in the same symptoms after 12 days (P = 0.000). Tukey test showed a significant improvement in the low FODMAP diet group and only a trend of improvement in the second group of SCD. The vitamin D mean value in both groups at the time of enrollment was 38 ng/mL; in the end, the mean value in the low FODMAP diet group was 32 ng/mL and in the SCD group was 22 ng/mL, with a statistically significant difference. The folic acid mean value at the time of enrollment was 18 mg/dL; in the end, the mean value in the low FODMAP diet group was 15 mg/dL and in the SCD group was 8 mg/dL, with a statistically significant difference.

CONCLUSION

Patients affected by IBS seem to have benefitted from a low FODMAP diet but not from an SCD, and a low FODMAP diet doesn't seem to cause vitamin D and folic acid deficiencies.

Irritable Bowel Syndrome

: Irritable bowel syndrome (IBS) is a common, chronic gastrointestinal (GI) condition characterized by disturbances in bowel habits and abdominal pain in the absence of known organic pathology. IBS reduces quality of life and is costly to treat. It is diagnosed using the symptom-based Rome criteria for functional GI disorders, which was recently updated and released as Rome IV. Both physiologic and psychological variables play a role in the etiology of IBS and perpetuate symptoms. Although research has shed light on IBS pathophysiology, therapeutic interventions remain symptom driven, employing both pharmacologic and nonpharmacologic approaches. Here, the authors review the epidemiology and pathophysiology of IBS, summarize diagnostic and treatment strategies, and discuss implications for nursing practice.

Evaluation of Benefit and Tolerability of IQP-CL-101 (Xanthofen) in the Symptomatic Improvement of Irritable Bowel Syndrome: A Double-Blinded, Randomised, Placebo-Controlled Clinical Trial

Irritable bowel syndrome (IBS) is a functional bowel disorder of unknown aetiology. There is currently no known cure, and pharmacological interventions are usually targeting symptomatic relief, where natural and herbal remedies also play a role. This study aimed to evaluate the benefit and tolerability of IQP-CL-101 in symptomatic IBS relief. A double-blinded, randomised, placebo-controlled trial was conducted over 8 weeks. A total of 99 subjects fulfilling ROME-III criteria for IBS were randomised into two groups, given either two IQP-CL-101 softgels or matching placebo twice daily before main meals. The primary endpoint was the difference in change of IBS Symptom Severity Score (IBS-SSS) after an 8-week intake of IQP-CL-101 compared to placebo. After 8 weeks, subjects on IQP-CL-101 showed a significant reduction in IBS-SSS (113.0 ± 64.9-point reduction) compared to subjects on placebo (38.7 ± 64.5-point reduction) (p < 0.001). A significant improvement could be seen as early as 4 weeks. No serious adverse events were reported throughout. IQP-CL-101 can be considered beneficial in the improvement of IBS symptom severity, regardless of IBS type, and therefore able to improve quality of life in patients suffering from abdominal pain and discomfort. © 2017 The Authors. Phytotherapy Research published by John Wiley & Sons Ltd.

Faecalibacterium prausnitzii: from microbiology to diagnostics and prognostics

There is an increasing interest in Faecalibacterium prausnitzii, one of the most abundant bacterial species found in the gut, given its potentially important role in promoting gut health. Although some studies have phenotypically characterized strains of this species, it remains a challenge to determine which factors have a key role in maintaining the abundance of this bacterium in the gut. Besides, phylogenetic analysis has shown that at least two different F. prausnitzii phylogroups can be found within this species and their distribution is different between healthy subjects and patients with gut disorders. It also remains unknown whether or not there are other phylogroups within this species, and also if other Faecalibacterium species exist. Finally, many studies have shown that F. prausnitzii abundance is reduced in different intestinal disorders. It has been proposed that F. prausnitzii monitoring may therefore serve as biomarker to assist in gut diseases diagnostics. In this mini-review, we aim to serve as an overview of F. prausnitzii phylogeny, ecophysiology and diversity. In addition, strategies to modulate the abundance of F. prausnitzii in the gut as well as its application as a biomarker for diagnostics and prognostics of gut diseases are discussed. This species may be a useful potential biomarker to assist in ulcerative colitis and Crohn's disease discrimination.

Irritable Bowel Syndrome, Particularly the Constipation-Predominant Form, Involves an Increase in Methanobrevibacter smithii, Which Is Associated with Higher Methane Production

BACKGROUND/AIMS

Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC).

METHODS

Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers.

RESULTS

Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log₁₀5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log₁₀6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=-0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log₁₀6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log₁₀6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021).

CONCLUSIONS

Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads.

Dietary Triggers in Irritable Bowel Syndrome: Is There a Role for Gluten?

A tight link exists between dietary factors and irritable bowel syndrome (IBS), one of the most common functional syndromes, characterized by abdominal pain/discomfort, bloating and alternating bowel habits. Amongst the variety of foods potentially evoking "food sensitivity", gluten and other wheat proteins including amylase trypsin inhibitors represent the culprits that recently have drawn the attention of the scientific community. Therefore, a newly emerging condition termed non-celiac gluten sensitivity (NCGS) or nonceliac wheat sensitivity (NCWS) is now well established in the clinical practice. Notably, patients with NCGS/NCWS have symptoms that mimic those present in IBS. The mechanisms by which gluten or other wheat proteins trigger symptoms are poorly understood and the lack of specific biomarkers hampers diagnosis of this condition. The present review aimed at providing an update to physicians and scientists regarding the following main topics: the experimental and clinical evidence on the role of gluten/wheat in IBS; how to diagnose patients with functional symptoms attributable to gluten/wheat sensitivity; the importance of double-blind placebo controlled cross-over trials as confirmatory assays of gluten/wheat sensitivity; and finally, dietary measures for gluten/wheat sensitive patients. The analysis of current evidence proposes that gluten/wheat sensitivity can indeed represent a subset of the broad spectrum of patients with a clinical presentation of IBS.

The Development of Irritable Bowel Syndrome: A Prospective Community-Based Cohort Study

OBJECTIVES

It remains controversial whether psychosocial burden is an independent predictor of irritable bowel syndrome (IBS) or occurs concurrently as an epiphenomenon. Here we prospectively examine the individual contribution of psychosocial risk factors, demographic factors, somatic symptoms, and gastrointestinal infection within a non-clinical, IBS-free population before infection occurred.

METHODS

A prospective community-based cohort study including a consecutive sample of healthy participants with an elevated risk of developing gastrointestinal infection during long-distance travel was conducted. Potential predictive factors were investigated using validated self-report scales pre-travel, 1 week after return, and 7 months post-travel. IBS was assessed using the ROME-III Diagnostic Questionnaire.

RESULTS

Of the 1,964 eligible long-distance travelers, 1,464 responded at follow-up directly after their journey, and 1,190 participants completed the study 7 months post-journey. Fifty-three percent of study completers were female, mean age was 39.9 (s.d.=15.7) years. The mean travel duration was 40.8 (s.d.=52.8) days, and 43.3% (95% confidence interval (CI)=40.4-46.1%) of participants experienced at least moderate infectious travelers' diarrhea. The incidence of newly developed IBS 7 months post-travel was 7.2% (95%CI=5.8-8.6%). In multivariate analyses, female gender, vulnerability to diarrhea under stress, baseline somatic symptom burden, baseline illness anxiety, diarrhea within the 4 months pre-travel, and travelers' diarrhea during the journey significantly predicted IBS post-travel.

CONCLUSION

This study indicates that gastrointestinal infection as well as predisposing factors such as female gender, vulnerability to diarrhea under stress, illness anxiety, and somatic symptom burden predict the development of IBS. The results indicate the necessity of simultaneously addressing both somatic and psychological needs in patients with IBS as early as possible.

THE INTESTINAL MICROBIOTA AND THE ROLE OF PROBIOTICS IN IRRITABLE BOWEL SYNDROME: a review

Irritable bowel syndrome is a common, chronic relapsing gastrointestinal disorder that affects 7%-22% of the population worldwide. According to Rome III Criteria, the disorder is defined by the coexistence of abdominal discomfort or pain associated with an alteration in bowel habits. Its pathophysiology is not completely understood but, in addition to some important abnormalities, the disturbed intestinal microbiota has also been described supported by several strands of evidence. The treatment of irritable bowel syndrome is based upon several therapeutic approaches but few have been successful or without adverse events and more recently the gut microbiota and the use of probiotics have emerged as a factor to be considered. Probiotics are live micro-organisms which when consumed in adequate amounts confer a health benefit to the host, such as Lactic bacteria among others. An important scientific rationale has emerged for the use of probiotics in irritable bowel syndrome, although the data regarding different species are still limited. Not all probiotics are beneficial: it is important to select the specific strain which should be supported by good evidence base. The mechanisms of action of probiotics are described and the main strains are quoted.

Patients' experiences of healthcare encounters in severe irritable bowel syndrome: an analysis based on narrative and feminist theory

AIMS AND OBJECTIVES

This study aimed to explore patients' experiences of healthcare encounters in severe irritable bowel syndrome.

BACKGROUND

Irritable bowel syndrome is a common functional disorder with symptoms such as abdominal pain and disturbed bowel habits, the cause of which is not completely known. Treatments options are limited, and healthcare encounters in irritable bowel syndrome have been described as unsatisfying and frustrating for both patients and professional healthcare providers. Furthermore, the influence of power on healthcare encounters has long been recognised, especially regarding the disadvantaged position of those suffering from functional illness which cannot be identified by commonly used tests or investigations.

METHODS

We interviewed 10 patients during 2014, all attending an outpatient clinic and suffering from severe irritable bowel syndrome. Relying on narrative and feminist theory, we explored how they actively negotiate professional discourse communicated to them in the clinical encounter.

RESULTS

The patients' experiences of healthcare encounters in irritable bowel syndrome were mostly described as negative, and often induced feelings of confusion and self-doubt. Positive encounters were described as being listened to, believed and taken seriously. Narrators found it especially problematic when healthcare professionals described irritable bowel syndrome as a minor disorder with primarily stress or psychological aetiology and put the responsibility for recovery onto the patient. Patients' actively negotiated such professional discourse by presenting a counternarrative describing their own suffering and strengths, experienced healthcare shortcomings and possible organic aetiology of irritable bowel syndrome.

CONCLUSIONS

Patients suffering from severe irritable bowel syndrome described how they often felt a need to protect their positive identities in the face of trivialisation and disbelief by healthcare professionals.

RELEVANCE TO CLINICAL PRACTICE

A deepened understanding of patients' experiences of healthcare encounters in irritable bowel syndrome could enable more helpful and supporting interventions by healthcare professionals.

Intolerance to environmental chemicals and sounds in irritable bowel syndrome: Explained by central sensitization?

This study tested the hypotheses of irritable bowel syndrome showing (1) comorbidity with chemical and sound intolerance, other types of functionally somatic syndromes, and psychiatric disorders and (2) stronger than normal affective reactions to and behavioral disruptions from odorous/pungent chemicals and sounds in daily life. These hypotheses were tested by means of data from a large-scale population-based questionnaire study. The results showed comorbidity in irritable bowel syndrome with chemical and sound intolerance, fibromyalgia, migraine, post-traumatic stress disorder, generalized anxiety disorder, panic syndrome, and depression as well as strong reactions/disruptions from odorous/pungent chemicals and sounds in irritable bowel syndrome.

Neuroimaging the brain-gut axis in patients with irritable bowel syndrome

AIM: To summarize and synthesize current literature on neuroimaging the brain-gut axis in patients with irritable bowel syndrome (IBS).

METHODS: A database search for relevant literature was conducted using PubMed, Scopus and Embase in February 2015. Date filters were applied from the year 2009 and onward, and studies were limited to those written in the English language and those performed upon human subjects. The initial search yielded 797 articles, out of which 38 were pulled for full text review and 27 were included for study analysis. Investigations were reviewed to determine study design, methodology and results, and data points were placed in tabular format to facilitate analysis of study findings across disparate investigations.

RESULTS: Analysis of study data resulted in the abstraction of four key themes: Neurohormonal differences, anatomic measurements of brain structure and connectivity, differences in functional responsiveness of the brain during rectal distention, and confounding/correlating patient factors. Studies in this review noted alterations of glutamate in the left hippocampus (HIPP), commonalities across IBS subjects in terms of brain oscillation patterns, cortical thickness/gray matter volume differences, and neuroanatomical regions with increased activation in patients with IBS: Anterior cingulate cortex, mid cingulate cortex, amygdala, anterior insula, posterior insula and prefrontal cortex. A striking finding among interventions was the substantial influence that patient variables (e.g., sex, psychological and disease related factors) had upon the identification of neuroanatomical differences in structure and connectivity.

CONCLUSION: The field of neuroimaging can provide insight into underlying physiological differences that distinguish patients with IBS from a healthy population.

Bifidobacterium animalis ssp. lactis CNCM-I2494 Restores Gut Barrier Permeability in Chronically Low-Grade Inflamed Mice

Growing evidence supports the efficacy of many probiotic strains in the management of gastrointestinal disorders associated with deregulated intestinal barrier function and/or structure. In particular, bifidobacteria have been studied for their efficacy to both prevent and treat a broad spectrum of animal and/or human gut disorders. The aim of the current work was thus to evaluate effects on intestinal barrier function of Bifidobacterium animalis ssp. lactis CNCM-I2494, a strain used in fermented dairy products. A chronic dinitrobenzene sulfonic acid (DNBS)-induced low-grade inflammation model causing gut dysfunction in mice was used in order to study markers of inflammation, intestinal permeability, and immune function in the presence of the bacterial strain. In this chronic low-grade inflammation mice model several parameters pointed out the absence of an over active inflammation process. However, gut permeability, lymphocyte populations, and colonic cytokines were found to be altered. B. animalis ssp. lactis CNCM-I2494 was able to protect barrier functions by restoring intestinal permeability, colonic goblet cell populations, and cytokine levels. Furthermore, tight junction (TJ) proteins levels were also measured by qRT-PCR showing the ability of this strain to specifically normalize the level of several TJ proteins, in particular for claudin-4. Finally, B. lactis strain counterbalanced CD4⁺ lymphocyte alterations in both spleen and mesenteric lymphoid nodes. It restores the Th1/Th2 ratio altered by the DNBS challenge (which locally augments CD4⁺ Th1 cells) by increasing the Th2 response as measured by the increase in the production of major representative Th2 cytokines (IL-4, IL-5, and IL-10). Altogether, these data suggest that B. animalis ssp. lactis CNCM-I2494 may efficiently prevent disorders associated with increased barrier permeability.

Irritable Bowel Syndrome May Be Associated with Elevated Alanine Aminotransferase and Metabolic Syndrome

PURPOSE

Recent studies have revealed close relationships between hepatic injury, metabolic pathways, and gut microbiota. The microorganisms in the intestine also cause irritable bowel syndrome (IBS). The aim of this study was to examine whether IBS was associated with elevated hepatic enzyme [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)], gamma-glutamyl transferase (γ-GT) levels, and metabolic syndrome (MS).

MATERIALS AND METHODS

This was a retrospective, cross-sectional, case-control study. The case and control groups comprised subjects who visited our health promotion center for general check-ups from June 2010 to December 2010. Of the 1127 initially screened subjects, 83 had IBS according to the Rome III criteria. The control group consisted of 260 age- and sex-matched subjects without IBS who visited our health promotion center during the same period.

RESULTS

Compared to control subjects, patients with IBS showed significantly higher values of anthropometric parameters (body mass index, waist circumference), liver enzymes, γ-GT, and lipid levels. The prevalences of elevated ALT (16.9% vs. 7.7%; p=0.015) and γ-GT (24.1% vs. 11.5%; p=0.037) levels were significantly higher in patients with IBS than in control subjects. A statistically significant difference was observed in the prevalence of MS between controls and IBS patients (12.7% vs. 32.5%; p<0.001). The relationships between elevated ALT levels, MS, and IBS remained statistically significant after controlling for potential confounding factors.

CONCLUSION

On the basis of our study results, IBS may be an important condition in certain patients with elevated ALT levels and MS.

No association between the common calcium-sensing receptor polymorphism rs1801725 and irritable bowel syndrome

BACKGROUND

The calcium-sensing receptor (CaSR) is a calcium (Ca(2+)) sensitive G protein-coupled receptor implicated in various biological processes. In particular, it regulates Ca(2+)/Mg(2+)- homeostasis and senses interstitial Ca(2+) levels and thereby controls downstream signalling cascades. Due to its expression in the gut epithelium, the enteric nervous system and smooth muscles and its key function in regulation and coordination of muscular contraction and secretion, it represents an excellent candidate gene to be investigated in the pathophysiology of irritable bowel syndrome (IBS). Disturbed CaSR structure and function may impact gastrointestinal regulation of muscular contraction, neuronal excitation and secretion and consequently contribute to symptoms seen in IBS, such as disordered defecation as well as disturbed gut motility and visceral sensitivity.

METHODS

We have therefore genotyped the functional CASR SNP rs1801725 in three case control samples from the UK, Belgium and the USA.

RESULTS

Genotype frequencies showed no association in the three genotyped case-control samples, neither with IBS nor with IBS subtypes.

CONCLUSIONS

Although we could not associate the SNP to any of the established bowel symptom based IBS subtypes we cannot rule out association to altered Ca(2+) levels and disturbed secretion and gut motility which were unfortunately not assessed in the patients genotyped. This underlines the necessity of a more detailed phenotyping of IBS patients and control individuals in future studies.

Diet low in FODMAPs reduces symptoms of irritable bowel syndrome as well as traditional dietary advice: a randomized controlled trial

BACKGROUND & AIMS

A diet with reduced content of fermentable short-chain carbohydrates (fermentable oligo-, di-, monosaccharides, and polyols [FODMAPs]) has been reported to be effective in the treatment of patients with irritable bowel syndrome (IBS). However, there is no evidence of its superiority to traditional dietary advice for these patients. We compared the effects of a diet low in FODMAPs with traditional dietary advice in a randomized controlled trial of patients with IBS.

METHODS

We performed a multi-center, parallel, single-blind study of 75 patients who met Rome III criteria for IBS and were enrolled at gastroenterology outpatient clinics in Sweden. Subjects were randomly assigned to groups that ate specific diets for 4 weeks-a diet low in FODMAPs (n = 38) or a diet frequently recommended for patients with IBS (ie, a regular meal pattern; avoidance of large meals; and reduced intake of fat, insoluble fibers, caffeine, and gas-producing foods, such as beans, cabbage, and onions), with greater emphasis on how and when to eat rather than on what foods to ingest (n = 37). Symptom severity was assessed using the IBS Symptom Severity Scale, and patients completed a 4-day food diary before and at the end of the intervention.

RESULTS

A total of 67 patients completed the dietary intervention (33 completed the diet low in FODMAPs, 34 completed the traditional IBS diet). The severity of IBS symptoms was reduced in both groups during the intervention (P < .0001 in both groups before vs at the end of the 4-week diet), without a significant difference between the groups (P = .62). At the end of the 4-week diet period, 19 patients (50%) in the low-FODMAP group had reductions in IBS severity scores ≥50 compared with baseline vs 17 patients (46%) in the traditional IBS diet group (P = .72). Food diaries demonstrated good adherence to the dietary advice.

CONCLUSIONS

A diet low in FODMAPs reduces IBS symptoms as well as traditional IBS dietary advice. Combining elements from these 2 strategies might further reduce symptoms of IBS. ClinicalTrials.gov ID NCT02107625.

Gut pain & visceral hypersensitivity

Visceral pain is a highly complex entity whose experience is variable in health and disease. It can occur in patients with organic disease and also in those without any readily identifiable structural or biochemical abnormality such as in the functional gastrointestinal disorders (FGID). Despite considerable progress in our understanding of the culpable underlying mechanisms significant knowledge gaps remain, representing a significant unmet need in gastroenterology. A key, but not universal, pathological feature is that patients with FGID often display heightened sensitivity to experimental gut stimulation, termed visceral hypersensitivity. A plethora of factors have been proposed to account for this epiphenomenon including peripheral sensitization, central sensitization, aberrant central processing, genetic, psychological and abnormalities within the stress responsive systems. Further research is needed, bringing together complementary research themes from a diverse array of academic disciplines ranging from gastroenterology to nociceptive physiology to functional neuro-imaging, to address this unmet need.

Fecal Microbiota in Patients with Irritable Bowel Syndrome Compared with Healthy Controls Using Real-Time Polymerase Chain Reaction: An Evidence of Dysbiosis

BACKGROUND

Dysbiosis may play a role in irritable bowel syndrome (IBS), hitherto an enigmatic disorder. We evaluated selected fecal microbes in IBS patients and healthy controls (HC).

METHODS

Fecal 16S rRNA copy number of selected bacteria was studied using qPCR in 47 patients with IBS (Rome III) and 30 HC.

RESULTS

Of 47 patients, 20 had constipation (IBS-C), 20 diarrhea (IBS-D), and seven unclassified IBS (IBS-U). Relative difference in 16S rRNA copy number of Bifidobacterium (P = 0.042) was lower, while those of Ruminococcus productus-Clostridium coccoides (P = 0.016), Veillonella (P = 0.008), Bacteroides thetaiotamicron (P < 0.001), Pseudomonas aeruginosa (P < 0.001), and Gram-negative bacteria (GNB, P = 0.001) were higher among IBS patients than HC. Number of Lactobacillus (P = 0.002) was lower, while that of Bacteroides thetaiotamicron (P < 0.001) and segmented filamentous bacteria (SFB, P < 0.001) was higher among IBS-D than IBS-C. Numbers of Bacteroides thetaiotamicron (P < 0.001), P. aeruginosa (P < 0.001), and GNB (P < 0.01) were higher among IBS-C and IBS-D than HC. Quantity of SFB was higher among IBS-D (P = 0.011) and lower among IBS-C (P = 0.002) than HC. Number of Veillonella species was higher among IBS-C than HC (P = 0.002). P. aeruginosa was frequently detected among IBS than HC (46/47 [97.9 %] vs. 10/30 [33.3 %], P < 0.001). Abdominal distension (n = 34/47) was associated with higher number of Bacteroides thetaiotamicron, Clostridium coccoides, P. aeruginosa, SFB, and GNB; bloating (n = 22/47) was associated with Clostridium coccoides and GNB. Microbial flora was different among IBS than HC on principal component analysis.

CONCLUSION

Fecal microbiota was different among IBS than HC, and different sub-types were associated with different microbiota. P. aeruginosa was more frequent and higher in number among IBS patients.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: "food", "diet", "food allergy", "food hypersensitivity", "food intolerance", "IBS", "epidemiology", "pathogenesis", "pathophysiology", "diagnosis", "treatment". We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

Diagnosis of Irritable Bowel Syndrome: Role of Potential Biomarkers

Irritable bowel syndrome is a disorder diagnosed on symptom-based criteria without inclusion of any objective parameter measurable by known diagnostic methods. Heterogeneity of the disorder and overlapping with more serious organic diseases increase uncertainty for the physician's work and increase the cost of confirming the diagnosis. This paper is an attempt to summarize the efforts to find adequate biomarkers for irritable bowel syndrome, which should shorten the time to diagnosis and reduce the cost. Most of the reviewed papers were observational studies from secondary care institutions. Since publication of the Rome III criteria in 2006, most recent studies use these for the recruitment of IBS patients. This is a positive step forward as future studies should use the same criteria, facilitating comparison of their results. Among the studied biomarkers, most evidence is provided for fecal calprotectin. Cutoff values for fecal calprotectin have still to be investigated prior to inclusion in the irritable bowel syndrome diagnostic algorithm.

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.

More similarities than differences between men and women with irritable bowel syndrome

BACKGROUND

Differences regarding symptoms, coping abilities, and quality of life (QOL) between men and women with irritable bowel syndrome (IBS) have been reported but data are sparse and sometimes conflicting. The aim of present study was to investigate gender differences in gastrointestinal, extra-intestinal, and psychological symptoms, and sense of coherence (SOC) and QOL in a large group of patients diagnosed with IBS.

METHODS

We analyzed questionnaire data from 557 patients (152 men) diagnosed with IBS consecutively included in studies at an outpatient clinic for functional bowel disorders between 2002 and 2010. Following questionnaires were included: IBS severity scoring system (IBS-SSS), Hospital Anxiety and Depression Scale (HAD), IBSQOL Scale, Visceral Sensitivity Index (VSI), SOC Scale, Bristol Stool Form Scale (BSFS), and Patient Health Questionnaire (PHQ-15).

KEY RESULTS

Women had harder stools (FDR-adjusted p-value: q = 0.033), more severe bloating (q = 0.020), higher symptom severity (q = 0.042), higher total somatic symptom burden (q = 0.035), lower SOC (q = 0.042), and lower QOL. Women rated more general anxiety (q = 0.017) and gastrointestinal-specific anxiety (q = 0.042), but there were no group differences in depression, pain, stool frequency, impact on daily life, dissatisfaction with bowel habit, or extra-colonic symptoms. The differences found were small (effect sizes: r < 0.3).

CONCLUSIONS & INFERENCES

In this study, we demonstrated more similarities than differences between men and women with IBS. The largest difference were seen for QOL which might reflect certain structural stressors to which women in general are more exposed than men.