Intestinal microbiota and its role in irritable bowel syndrome (IBS)

Biological, environmental, and psychological stress and the human gut microbiome in healthy adults

Emerging research suggests that the gut microbiome plays a crucial role in stress. We assess stress-microbiome associations in two samples of healthy adults across three stress domains (perceived stress, stressful life events, and biological stress /Respiratory Sinus Arrhythmia; RSA). Study 1 (n = 62; mean-age = 37.3 years; 68% female) and Study 2 (n = 74; mean-age = 41.6 years; female only) measured RSA during laboratory stressors and used 16S rRNA pyrosequencing to classify gut microbial composition from fecal samples. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was used to predict functional pathways of metagenomes. Results showed differences in beta diversity between high and low stressful life events groups across both studies. Study 1 revealed differences in beta diversity between high and low RSA groups. In Study 1, the low perceived stress group was higher in alpha diversity than the high perceived stress group. Levels of Clostridium were negatively associated with RSA in Study 1 and levels Escherichia/Shigella were positively associated with perceived stress in Study 2. Associations between microbial functional pathways (L-lysine production and formaldehyde absorption) and RSA are discussed. Findings suggest that certain features of the gut microbiome are differentially associated with each stress domain.

Applicability of the Pancreatic Exocrine Insufficiency Test (PEI-TEST) in Pediatric Patients

In mild cases, it is difficult to diagnose pancreatic exocrine insufficiency (PEI). There is no gold standard method for the diagnosis of PEI. A reliable method is needed for preliminary diagnosis of PEI. The PEI-TEST was applied to the patients with nonspecific gastrointestinal complaints. Serum amylase, lipase, serum trypsinogen, and fecal elastase 1 (FE-1) were analyzed from each patient. According to the PEI-TEST, PEI was present in 42 (47.7%) and PEI was not present in 46 (52.3%) patients. No significant difference was observed between the 2 groups with regard to age, gender and amylase, lipase, serum trypsinogen, and FE-1. When an FE-1 value of <200 µg/dL was considered as indicating PEI, the sensitivity and specificity of the test were found to be 47.4% and 52.2%, respectively. Although it is promising that PEI-TEST is a validated test in our country and suitable for our society, it is not suitable for pediatric patients.

The role of miRNA in IBS pathogenesis, diagnosis and therapy: The latest thought

IBS is a prevalent clinical condition affecting bowel function. There is a restricted comprehension of its pathogenesis, an absence of particular diagnostic tools, and an insufficiency of efficient pharmacological remedies. MiRNAs are a highly conserved class of non-coding small molecule RNAs, with a length of 20-24 nucleotides. Research has shown the presence of a number of differentially expressed miRNAs in the colonic tissue and peripheral blood of IBS patients. Meanwhile, miRNAs have a critical role in gene expression and the pathology of IBS as they act as significant mediators of post-transcriptional gene silencing. The investigation of miRNA molecular regulatory networks proves useful in examining the convoluted pathogenesis of IBS. This paper presents a review of recent literature on miRNAs associated with IBS, explains how miRNAs contribute to the development of IBS, and assesses the potential usefulness of miRNA analysis for diagnosing and treating IBS.

Gut microbial signatures of patients with diarrhea-predominant irritable bowel syndrome and their healthy relatives

AIMS

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder, encompassing diarrhea-predominant irritable bowel syndrome (IBS-D). Here, we utilized 16S rDNA gene sequencing to identify potential microbial drivers of IBS-D.

METHODS AND RESULTS

A total of 30 healthy relatives and 27 patients with IBS-D were recruited. Clinical data and fecal samples were collected from patients and controls. 16S rDNA gene sequencing was performed to obtain fecal bacterial data. Differences in community composition were evaluated utilizing analysis of similarity (ANOSIM) using Bray-Curtis dissimilarity. The Wilcoxon rank sum test was used to compare differences in taxa and functional pathways. Finally, the key gut microbiota was identified using the random forest algorithm. Gut microbiota diversity, estimated through the Observe, Chao1, and abundance-based coverage estimator (ACE) indices, was significantly lower in the IBS-D patients than in the healthy relatives. ANOSIM analysis further confirmed significant differences in the composition of the gut microbiota between IBS-D patients and healthy relatives, with an R value of 0.106 and a P-value of 0.005. Notably, the IBS-D patients exhibited a significant enrichment of specific bacterial genera, including Fusicatenibacter, Streptococcus, and Klebsiella, which may possess potential pathogenic properties. In particular, the bacterial genus Klebsiella demonstrated a positive correlation with irritable bowel syndrome severity scoring system scores. Conversely, healthy subjects showed enrichment of bacterial genera such as Alistipes, Akkermansia, and Dialister, which may be beneficial bacteria in IBS-D. Utilizing the random forest model, we developed a discriminative model for IBS-D based on differential bacterial genera. This model exhibited impressive performance, with an area under the curve value of 0.90. Additionally, our analysis did not reveal any gender-specific differences in the microbiota community composition among IBS-D patients.

CONCLUSIONS

Our findings offer preliminary insights into the potential relationship between intestinal microbiota and IBS-D. The identification model for IBS-D, grounded in gut microbiota, holds promising prospects for improving early diagnosis of IBS-D.

Impact of bread diet on intestinal dysbiosis and irritable bowel syndrome symptoms in quiescent ulcerative colitis: A pilot study

Gut microbiota may be involved in the presence of irritable bowel syndrome (IBS)-like symptomatology in ulcerative colitis (UC) patients in remission. Bread is an important source of dietary fiber, and a potential prebiotic. To assess the effect of a bread baked using traditional elaboration, in comparison with using modern elaboration procedures, in changing the gut microbiota and relieving IBS-like symptoms in patients with quiescent ulcerative colitis. Thirty-one UC patients in remission with IBS-like symptoms were randomly assigned to a dietary intervention with 200 g/d of either treatment or control bread for 8 weeks. Clinical symptomatology was tested using questionnaires and inflammatory parameters. Changes in fecal microbiota composition were assessed by high-throughput sequencing of the 16S rRNA gene. A decrease in IBS-like symptomatology was observed after both the treatment and control bread interventions as reductions in IBS-Symptom Severity Score values (p-value < 0.001) and presence of abdominal pain (p-value < 0.001). The treatment bread suggestively reduced the Firmicutes/Bacteroidetes ratio (p-value = 0.058). In addition, the Firmicutes/Bacteroidetes ratio seemed to be associated with improving IBS-like symptoms as suggested by a slight decrease in patient without abdominal pain (p-value = 0.059). No statistically significant differential abundances were found at any taxonomic level. The intake of a bread baked using traditional elaboration decreased the Firmicutes/Bacteroidetes ratio, which seemed to be associated with improving IBS-like symptoms in quiescent ulcerative colitis patients. These findings suggest that the traditional bread elaboration has a potential prebiotic effect improving gut health (ClinicalTrials.gov ID number of study: NCT05656391).

Probiotics in Functional Gastrointestinal Disorders

The most frequent functional gastrointestinal disorders (FGID) in children include infantile colic, constipation, functional abdominal pain (FAP), and irritable bowel syndrome (IBS). Unfortunately, treatment options for FGID in children are limited, therefore many dietary interventions have been evaluated, including probiotics. This chapter summarizes currently available evidence and recommendations for probiotic use in the treatment of frequent FGIDs in children. The strongest evidence exists for the use of Limosilactobacillus (L.) reuteri DSM 17938 and Bifidobacterium animalis subsp. lactis BB-12 for the treatment of infantile colic in breastfed infants. Limited but yet encouraging evidence exists for Lacticaseibacillus rhamnosus GG (LGG) for the treatment of IBS and L. reuteri DSM 17938 for FAP.

Targeting the gut-microbiota-brain axis in irritable bowel disease to improve cognitive function - recent knowledge and emerging therapeutic opportunities

The brain-gut axis forms a bidirectional communication system between the gastrointestinal (GI) tract and cognitive brain areas. Disturbances to this system in disease states such as inflammatory bowel disease have consequences for neuronal activity and subsequent cognitive function. The gut-microbiota-brain axis refers to the communication between gut-resident bacteria and the brain. This circuits exists to detect gut microorganisms and relay information to specific areas of the central nervous system (CNS) that in turn, regulate gut physiology. Changes in both the stability and diversity of the gut microbiota have been implicated in several neuronal disorders, including depression, autism spectrum disorder Parkinson's disease, Alzheimer's disease and multiple sclerosis. Correcting this imbalance with medicinal herbs, the metabolic products of dysregulated bacteria and probiotics have shown hope for the treatment of these neuronal disorders. In this review, we focus on recent advances in our understanding of the intricate connections between the gut-microbiota and the brain. We discuss the contribution of gut microbiota to neuronal disorders and the tangible links between diseases of the GI tract with cognitive function and behaviour. In this regard, we focus on irritable bowel syndrome (IBS) given its strong links to brain function and anxiety disorders. This adds to the growing body of evidence supporting targeted therapeutic strategies to modulate the gut microbiota for the treatment of brain/mental-health-related disease.

Non-pharmacologic approaches to treatment of pediatric functional abdominal pain disorders

Functional abdominal pain disorders (FAPDs) affect up to 25% of children in the United States. These disorders are more recently known as disorders of "brain-gut" interaction. The diagnosis is based on the ROME IV criteria, and requires the absence of an organic condition to explain the symptoms. Although these disorders are not completely understood, several factors have been involved in the pathophysiology including disordered gut motility, visceral hypersensitivity, allergies, anxiety/stress, gastrointestinal infection/inflammation, as well dysbiosis of the gut microbiome. The pharmacologic and non-pharmacologic treatments for FAPDs are directed to modifying these pathophysiologic mechanisms. This review aims to summarize the non-pharmacologic interventions used in the treatment of FAPDs including dietary modifications, manipulation of the gut microbiome (neutraceuticals, prebiotics, probiotics, synbiotics and fecal microbiota transplant) and psychological interventions that addresses the "brain" component of the brain-gut axis (cognitive behavioral therapy, hypnotherapy, breathing and relaxation techniques). In a survey conducted at a large academic pediatric gastroenterology center, 96% of patients with functional pain disorders reported using at least 1 complementary and alternative medicine treatment to ameliorate symptoms. The paucity of data supporting most of the therapies discussed in this review underscores the need for large randomized controlled trials to assess their efficacy and superiority compared to other treatments.

Constipation-Predominant Irritable Bowel Syndrome (IBS-C): Effects of Different Nutritional Patterns on Intestinal Dysbiosis and Symptoms

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by abdominal pain associated with defecation or a change in bowel habits. The pathogenesis of IBS is not completely clear, but it is known to be multifactorial and complex. Endogenous and exogenous factors such as abnormal GI motility, low-grade inflammation, increased epithelial permeability and visceral hypersensitivity, but diet and psychosocial aspects are also recognized as important actors. Furthermore, the interaction between diet and gut microbiota has gained interest as a potential contributor to the pathophysiology of IBS. To date, there is no specific diet for IBS with constipation (IBS-C); however, many studies show that fiber intake, especially soluble fiber such as inulin, could have a positive effect on symptoms. This review aims to evaluate the effects of some nutritional components such as fibers but also functional foods, prebiotics, probiotics and symbiotics on symptoms and microbiota in IBS-C subjects.

Rice Water-Fried Atractylodis Rhizoma Relieves Spleen Deficiency Diarrhea by Regulating the Intestinal Microbiome

Background

Spleen deficiency diarrhea (SDD) is a common Traditional Chinese Medicine (TCM) gastrointestinal condition, the causes of which include dysfunction of the intestinal barrier and microbiota. Rice water-fried Atractylodis Rhizoma (RAR) is a commonly used drug to treat this condition, but its mechanism remains unclear. This study explored the related mechanisms of ethanolic extract of rice water-fried Atractylodis Rhizoma (EAR) in the treatment of SDD by examining changes in the intestinal microbiota.

Method

Wistar rats were randomly divided into 4 groups including the control, model, EAR low, and high-dose groups, 6 rats in each group. All rats, except the control group, were induced to develop SDD by a bitter-cold purgation method with rhubarb. The therapeutic effect of EAR on SDD was evaluated by pathological sections, inflammatory indicators (TNF-α, IL-1β, and IL-10), gastrointestinal-related indicators (GAS, DAO, D-lactate, VIP, and SIgA), and intestinal flora (bacteria and fungi) analysis.

Results

The results showed that the developed SDD rat model (model group) showed weight loss, decreased food intake, and increased fecal moisture content. Compared with those of the control group, the levels of TNF-α, IL-1β, DAO, D-lactate, and VIP in the model group were significantly increased, but the levels of IL-10, GAS and SIgA were significantly decreased (p < 0.05). However, the indicators were significantly improved after EAR treatment, indicating that EAR maintained the balance of pro- and anti-inflammatory cytokines and reduced gastric emptying, thereby protecting intestinal barrier function, alleviating intestinal mucosal injury, and relieving SDD by regulating the release of neurotransmitters. EAR was also shown to prevent infection by promoting the accumulation of noninflammatory immunoglobulin SIgA and improving intestinal mucosal immunity to inhibit the adhesion of bacteria, viruses, and other pathogens. Intestinal microbiome analysis showed that the intestinal bacteria and fungi of SDD model rats changed greatly compared with the control group, resulting in intestinal microecological imbalance. The reversal in the composition of the flora after EAR treatment was mainly characterized by a large enrichment of beneficial bacteria represented by Lactobacillus and a decrease in the abundance of potentially pathogenic fungi represented by Aspergillus. Thus, it was speculated that EAR primarily functions to alleviate SDD by increasing the abundance of beneficial bacteria and reducing the abundance of potentially pathogenic fungi.

Conclusion

The strong therapeutic effect of EAR on SDD suggests that it is a promising treatment for this condition.

A postbiotic fermented oat gruel may have a beneficial effect on the colonic mucosal barrier in patients with irritable bowel syndrome

BACKGROUND

Impaired intestinal permeability and microbial dysbiosis are important pathophysiological mechanisms underlying irritable bowel syndrome (IBS). ReFerm®, also called Profermin®, is a postbiotic product of oat gruel fermented with Lactobacillus plantarum 299v. In this study, we investigated whether ReFerm® has a beneficial effect on the intestinal epithelial barrier function in patients with IBS.

MATERIALS AND METHODS

Thirty patients with moderate to severe IBS-diarrhoea (IBS-D) or IBS-mixed (IBS-M) were treated with enema containing ReFerm® or placebo. The patients underwent sigmoidoscopy with biopsies obtained from the distal colon at baseline and after 14 days of treatment with ReFerm® or placebo twice daily. The biopsies were mounted in Ussing chambers, and paracellular and transcellular permeabilities were measured for 120 min. In addition, the effects of ReFerm® or placebo on the epithelial barrier were investigated in vitro using Caco-2 cells.

RESULTS

ReFerm® reduced paracellular permeability (p < 0.05) and increased transepithelial resistance (TER) over time (p < 0.01), whereas the placebo had no significant effect in patients. In ReFerm®-treated Caco-2 cells, paracellular and transcellular permeabilities were decreased compared to the control (p < 0.05) and placebo (p < 0.01). TER was increased in Caco-2 ReFerm®-treated cells, and normalised TER was increased in ReFerm®-treated Caco-2 cells compared to control (p < 0.05) and placebo-treated (p < 0.05) cells.

CONCLUSION

ReFerm® significantly reduced paracellular permeability and improved TER in colonic biopsies collected from patients with IBS and in a Caco-2 cell model. Our results offer new insights into the potential benefits of ReFerm® in IBS management. Further studies are needed to identify the molecular mechanisms underlying the barrier-protective properties of ReFerm®.

CLINICAL TRIAL REGISTRATION

[https://clinicaltrials.gov/], identifier [NCT05475314].

Fecal Microbiota Transplantation as New Therapeutic Avenue for Human Diseases

The human body is home to a variety of micro-organisms. Most of these microbial communities reside in the gut and are referred to as gut microbiota. Over the last decades, compelling evidence showed that a number of human pathologies are associated with microbiota dysbiosis, thereby suggesting that the reinstatement of physiological microflora balance and composition might ameliorate the clinical symptoms. Among possible microbiota-targeted interventions, pre/pro-biotics supplementations were shown to provide effective results, but the main limitation remains in the limited microbial species available as probiotics. Differently, fecal microbiota transplantation involves the transplantation of a solution of fecal matter from a donor into the intestinal tract of a recipient in order to directly change the recipient's gut microbial composition aiming to confer a health benefit. Firstly used in the 4th century in traditional Chinese medicine, nowadays, it has been exploited so far to treat recurrent Clostridioides difficile infections, but accumulating data coming from a number of clinical trials clearly indicate that fecal microbiota transplantation may also carry the therapeutic potential for a number of other conditions ranging from gastrointestinal to liver diseases, from cancer to inflammatory, infectious, autoimmune diseases and brain disorders, obesity, and metabolic syndrome. In this review, we will summarize the commonly used preparation and delivery methods, comprehensively review the evidence obtained in clinical trials in different human conditions and discuss the variability in the results and the pivotal importance of donor selection. The final aim is to stimulate discussion and open new therapeutic perspectives among experts in the use of fecal microbiota transplantation not only in Clostridioides difficile infection but as one of the first strategies to be used to ameliorate a number of human conditions.

Changes in colonic enteroendocrine cells of patients with irritable bowel syndrome following fecal microbiota transplantation

OBJECTIVES

The aim was to investigate the effect of fecal microbiota transplantation (FMT) on colonic enteroendocrine cells densities in patients with irritable bowel syndrome (IBS).

MATERIALS AND METHODS

This study is connected to the REFIT study, a double-blinded placebo-controlled trial to investigate using FMT for IBS treatment. Eighty-three subjects received either donor-FMT or placebo FMT (own feces) by colonoscope to cecum. Biopsies were obtained from sigmoid colon. Ten responders and ten non-responders consented to new biopsy one-year after FMT. Sixteen patients received donor-FMT and four received placebo FMT. Biopsies were immunostained for all of the colonic enteroendocrine cells and were quantified using computerized image analysis.Allocation sequence was revealed after obtaining re-biopsies and cells quantification.

RESULTS

Scores for IBS-SSS (mean ± SEM) of responders (eight of 10 patients who received donor FMT) and non-responders changed from baseline to one year after FMT (297 ± 11 and 81 ± 16, p < .0001, and 270 ± 17 and 291 ± 16, p = .15, respectively). Using paired t-test to compare enteroendocrine cells densities one-year after FMT to baseline showed significant increase only in somatostatin immunoreactive cells density in the total IBS responders group (p = .023) and who received donor-FMT (p = .038). The densities of peptide YY and enteroglucagon immunoreactive cells increased significantly (p = .04 and .035, respectively) in donor-FMT recipients. No significant changes were noted in placebo FMT or nonresponders subgroups.

CONCLUSION

This study shows that colonic enteroendocrine cells densities significantly change in responders group that received donor-FMT. The mechanisms for the cross talks between gut microbiota and colonic enteroendocrine cells remain to be investigated.

Effect of a Symbiotic Mixture on Fecal Microbiota in Pediatric Patients Suffering of Functional Abdominal Pain Disorders

(1) Background: Functional abdominal pain disorders (FAPDs) represent one of the main etiologies of chronic abdominal pain in the pediatric population. A wide spectrum of probiotic or prebiotic mixtures has been evaluated in trials regarding benefits in patients with FAPDs, mainly in the adult population. (2) Methods: This study was interested in evaluating the effect of oral supplementation with a symbiotic mixture on intestinal microbiota in children with functional dyspepsia (FD), irritable bowel syndrome with diarrhea (IBS-D), and irritable bowel syndrome with constipation (IBS-C). A combination of six bacterial strains (Lactobacillus rhamnosus R0011, Lactibacillus casei R0215, Bifidobacterium lactis BI-04, Lactobacillus acidophilus La-14, Bifidobacterium longum BB536, Lactobacillus plantarum R1012) and 210 mg of fructo-oligosaccharides-inulin were administered orally, daily, for 12 weeks and patients were scored for severity of symptoms and fecal microbiota before and after the treatment. (3) Results: The proportion of patients with adequate symptom relief was higher in the IBS-D than in the IBS-C group; however, the difference was not statistically significant (74.4% vs. 61.9%, p = 0.230). There was an increasing proportion of bacterial genera associated with health benefits, for both IBS-C and IBS-D (IBS-C: 31.1 ± 16.7% vs. 47.7 ± 13.5%, p = 0.01; IBS-D: 35.8 ± 16.2% vs. 44.1 ± 15.1%, p = 0.01). (4) Conclusions: Administration of a symbiotic preparation resulted in significant changes to the microbiota and gastrointestinal symptoms in patients with FAPDs.

Congestion in Patients with Advanced Heart Failure: Assessment and Treatment

Heart failure (HF) is characterized by frequent hospital admissions due to acute decompensation and shortened life span with a progressive clinical course leading to an advanced stage where traditional therapies become ineffective. Due to aging of the population and improved therapies, only a small of proportion of patients with advanced HF are candidates for surgical treatments, such as mechanical circulatory support or heart transplantation. In most cases, prompt identification and management of congestion is paramount to improving symptoms and quality of life and avoiding progression to severe multiorgan dysfunction and death.

Functional Dyspepsia: Diagnostic and Therapeutic Approaches

Functional dyspepsia is a common functional gastrointestinal (GI) disorder of gastroduodenal origin, diagnosed clinically in the presence of prototypical symptoms of epigastric pain and meal-related symptoms, and without structural explanation. The most recent diagnostic criteria provide for two functional dyspepsia subtypes, epigastric pain syndrome (EPS) and post-prandial distress syndrome (PDS) based on the predominant symptom pattern. The evaluation of dyspepsia should keep laboratory, imaging, and invasive testing to a minimum, as extensive or repetitive investigations are of rather low diagnostic yield in the absence of localizing symptoms or alarm features. Factors with etiopathologic relationships to functional dyspepsia include micro-inflammation, GI infections, abnormalities of gastroduodenal motility, visceral hypersensitivity, disturbances along the brain-gut axis, and psychological factors; all of these causative mechanisms have potential to partially explain symptoms in some functional dyspepsia patients, thus providing a rationale for the efficacy of a diversity of therapeutic approaches to functional dyspepsia. Management of dyspepsia symptoms relies upon both pharmacologic treatments and non-pharmacologic approaches, including psychological and complementary interventions. The evidence in support of established functional dyspepsia therapies is reviewed, and forms the basis for an effective functional dyspepsia treatment strategy emphasizing the patient's current symptom severity, pattern, and impact on the function and quality of life of the individual.

Responses to faecal microbiota transplantation in female and male patients with irritable bowel syndrome

BACKGROUND

Faecal microbiota transplantation (FMT) seems to be a promising treatment for irritable bowel syndrome (IBS) patients. In Western countries (United States and Europe), there is a female predominance in IBS. A sex difference in the response to FMT has been reported recently in IBS patients.

AIM

To investigate whether there was a sex difference in the response to FMT in the IBS patients who were included in our previous randomized controlled trial of the efficacy of FMT.

METHODS

The study included 164 IBS patients who participated in our previous randomized controlled trial. These patients had moderate-to-severe IBS symptoms belonging to the IBS-D (diarrhoea-predominant), IBS-C (constipation-predominant) and IBS-M (mixed) subtypes, and had not responded to the National Institute for Health and Care Excellence (NICE)-modified diet. They belonged in three groups: placebo (own faeces), and active treated group (30-g or 60-g superdonor faeces). The patients completed the IBS severity scoring system (IBS-SSS), Fatigue Assessment Scale (FAS) and the IBS quality of life scale (IBS-QoL) questionnaires at the baseline and 2 wk, 1 mo and 3 mo after FMT. They also provided faecal samples at the baseline and 1 mo after FMT. The faecal bacteria profile and dysbiosis were determined using the 16S rRNA gene polymerase chain reaction DNA amplification covering V3-V9; probe labelling by single nucleotide extension and signal detection. The levels of short-chain fatty acids (SCFAs) were determined by gas chromatography and flame ionization.

RESULTS

There was no sex difference in the response to FMT either in the placebo group or active treated group. There was no difference between females and males in either the placebo group or actively treated groups in the total score on the IBS-SSS, FAS or IBS-QoL, in dysbiosis, or in the faecal bacteria or SCFA level. However, the response rate was significantly higher in females with diarrhoea-predominant (IBS-D) than that of males at 1 mo, and 3 mo after FMT. Moreover, IBS-SSS total score was significantly lower in female patients with IBS-D than that of male patients both 1 mo and 3 mo after FMT.

CONCLUSION

There was no sex difference in the response to FMT among IBS patients with moderate-to-severe symptoms who had previously not responded to NICE-modified diet. However, female patients with IBS-D respond better and have higher reduction of symptoms than males after FMT.

The Effects of Fecal Microbiota Transplantation on the Symptoms and the Duodenal Neurogenin 3, Musashi 1, and Enteroendocrine Cells in Patients With Diarrhea-Predominant Irritable Bowel Syndrome

Introduction

Interactions between the gut microbiota and enteroendocrine cells play important role in irritable bowel syndrome (IBS). Reduced stem cell densities and their differentiation into enteroendocrine cells may cause abnormal densities of the duodenal enteroendocrine cells in IBS patients.

Materials and Methods

We aimed to investigate the effects of fecal microbiota transplantation (FMT) on stem cell differentiation into enteroendocrine cells as detected by neurogenin 3, stem cells as detected by Musashi 1, and the enteroendocrine cells in the duodenum of IBS patients. The study included 16 IBS patients according to Rome III criteria. Four patients were excluded. The remaining patients (n = 12, four females and eight males) were divided according to the cause of IBS into post-infectious (n = 6) and idiopathic (n = 6) IBS. They completed the following questionnaires before and 3 weeks after FMT: IBS-Symptom Severity Scoring system (IBS-SSS) and IBS-Symptom Questionnaire (IBS-SQ). Feces donated by healthy relatives of the patients were transplanted via gastroscope. Biopsies were taken from the descending part of the duodenum at baseline and 3 weeks after FMT. They were immunostained for neurogenin 3, Musashi 1, and all types of duodenal enteroendocrine cells and quantified by computerized image analysis. Microbiota analyses of feces collected just before and 3 weeks after FMT were performed using GA-map™ Dysbiosis test (Genetic Analysis AS, Oslo, Norway).

Results

The total scores for IBS-SSS and IBS-SQ were significantly improved 3 weeks after receiving FMT, P = 0.0009 and <0.0001, respectively. The stem cell densities of neurogenin 3 increased significantly following FMT (P = 0.0006) but not for Musashi 1 (P = 0.42). The cell densities of chromogranin A, cholecystokinin, gastric inhibitory peptide, serotonin, and somatostatin, but not for secretin, have significantly changed in both IBS groups after 3 weeks from receiving FMT.

Conclusion

More than two-thirds of IBS patients experienced improvement in their symptoms parallel to changes in the enteroendocrine cells densities 3 weeks after FMT. The changes in the enteroendocrine cell densities do not appear to be caused by changes in the stem cells or their early progenitors rather by changes in the differentiation progeny as detected by neurogenin 3. The study was retrospectively registered at ClinicalTrials.gov (ID: NCT03333291).

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT03333291.

Dietary habits in Greek children with functional constipation based on Rome III criteria: a school-based, cross-sectional multivariate analysis

Background

Functional constipation (FC) is the most common gastrointestinal disorder of childhood and has a multifactorial etiology. We aimed to assess dietary habits in Greek children with FC compared to the general population (control group, CG).

Methods

This was a subgroup analysis of a school-based, cross-sectional study carried out in children 6-18 years of age, between January and June 2014, using the Rome III criteria for the diagnosis of FC. Dietary parameters, as well as socioeconomic and demographic data and their association with the likelihood of FC, were analyzed through multivariate logistic regression analysis and expressed as odds ratios (OR).

Results

A total of 1439 children (1218 CG, 221 FC) were included in the analysis. The final model showed that consumption of was the only dietary parameter significantly related to FC; higher frequency of consumption was inversely related to the likelihood of FC (OR: 0.98, 95% CI: 0.96, 0.99, P=0.048). Significant socioeconomic confounders with a positive association with FC were: parental educational level, victimization, physical activity and number of adults at home.

Conclusions

Increased frequency of fiber consumption is significantly associated with higher odds of FC irrespective of socioeconomic background and lifestyle parameters. Interventional studies are required to validate these cross-sectional observations.

Irritable bowel syndrome and Parkinson's disease risk: register-based studies

To examine whether irritable bowel syndrome (IBS) was related to the future risk of Parkinson's disease (PD), we conducted a nested case-control study in the Swedish total population including 56,564 PD cases identified from the Swedish Patient Register and 30 controls per case individually matched by sex and year of birth. Odds ratios (ORs) with 95% confidence intervals (CIs) for having a prior diagnosis of IBS were estimated using conditional logistic regression. We furthermore conducted a cohort study using the Swedish Twin Registry following 3046 IBS patients identified by self-reported abdominal symptoms and 41,179 non-IBS individuals. Through Cox proportional hazard models, we estimated hazard ratios (HRs) and 95% CIs for PD risk. In the nested case-control study, 253 (0.4%) PD cases and 5204 (0.3%) controls had a previous IBS diagnosis. IBS diagnosis was associated with a 44% higher risk of PD (OR = 1.44, 95% CI 1.27-1.63). Temporal relationship analyses showed 53% and 38% increased risk of PD more than 5 and 10 years after IBS diagnosis, respectively. In the cohort analysis based on the Swedish Twin Registry, there was no statistically significantly increased risk of PD related to IBS (HR = 1.25, 95% CI = 0.87-1.81). Our results suggest a higher risk of PD diagnosis after IBS. These results provide additional evidence supporting the importance of the gut-brain axis in PD.

Effect of inulin in the treatment of irritable bowel syndrome with constipation (Review)

At present, irritable bowel syndrome (IBS) is a common medical problem all over the world that implies considerable social burden and high costs. Considering the different pathophysiological pathways, unitary management for IBS is not possible. Of the therapeutic approaches that have been proposed so far, only a few have been demonstrated to have beneficial effects in IBS patients. The implication of gut microbiota in IBS is obvious, similarly to the therapeutic effect of pro-/prebiotics, which is reflected by the latest publications. The intake of inulin seems to regulate the bowel peristalsis and colonic transit, the consistency and frequency of the stools, as it changes the composition of gut microbiota. The beneficial effect of inulin in patients with IBS-constipation form (IBS-C) is obvious, but still, more randomized controlled clinical trials involving large samples of patients are needed in order to provide more evidence.

Mucosal Tuft Cell Density Is Increased in Diarrhea-Predominant Irritable Bowel Syndrome Colonic Biopsies

Tuft cells are rare chemosensory sentinels found in the gut epithelium. When triggered by helminth infection, tuft cells secrete interleukin-25 (IL-25) basolaterally and subsequently evoke an immune response. Irritable bowel syndrome (IBS) is a common and heterogeneous disorder characterized by bowel dysfunction and visceral pain sensitivity. Dysfunctional gut-brain communication and immune activation contribute to the pathophysiology of this disorder. The study aims were to investigate changes in tuft cell density in non-post-infectious IBS patients. Immunofluorescent labeling of DCLK1-positive tuft cells was carried out in mucosal biopsies from the distal colons of diarrhea and constipation-predominant IBS patients and healthy controls. Tuft cell numbers were also assessed in animal models. Concentrations of interleukin-25 (IL-25) secreted from colonic biopsies and in plasma samples were analyzed using an immunoassay. The density of tuft cells was increased in diarrhea-but not constipation-predominant IBS patient colonic biopsies. Biopsy secretions and plasma concentrations of IL-25 were elevated in diarrhea-but not constipation-predominant IBS participants. Tuft cell hyperplasia was detected in a rat model of IBS but not in mice exposed to chronic stress. Tuft cell hyperplasia is an innate immune response to helminth exposure. However, the patients with diarrhea-predominant IBS have not reported any incidents of enteric infection. Moreover, rats exhibiting IBS-like symptoms displayed increased tuft cell density but were not exposed to helminths. Our findings suggest that factors other than helminth exposure or chronic stress lead to tuft cell hyperplasia in IBS colonic biopsies.

Higher prevalence of obesity among children with functional abdominal pain disorders

Background

Functional abdominal pain (FAP) disorders are one of the most common gastrointestinal disorders in children. We aimed to define the association between obesity and functional abdominal pain (FAP) disorders and to assess differences between overweight/obese children and normal weight children with FAP disorders.

Methods

We conducted a retrospective study of children (2–18 years old) with a clinical diagnosis of FAP who were followed-up in our pediatric gastroenterology unit between 1/2016–10/2018. FAP disorders were defined according to the ROME IV criteria. Body mass index (BMI) percentiles were defined by CDC standards. Patients with BMIs ≥85th percentile were designated as being overweight/obese. A population control group was obtained from the 2015–2016 Israel national health survey.

Results

Data from 173 children with FAP disorders (median age 11.5 years, 114 females) were included. Seventy-one children (41%) were classified as having functional abdominal pain-NOS, 67 (38.7%) as having irritable bowel syndrome (IBS), and 35 (20.2%) has having functional dyspepsia. Fifty-three children (30.6%) were classified as being overweight/obese.

Adolescents with FAP disorders had a significantly higher prevalence of overweight/obesity compared to controls (39.5% vs. 30%, respectively, p = 0.04). Children with FAP and overweight were older [12.4 (range 9.8–15.3) vs. 10.8 (7.4–14.1) years, p = 0.04] and had more hospitalizations due to FAP (20.8% vs. 7.6%, p = 0.01) compared to Children with FAP and normal weight.

Conclusions

Adolescents with FAP had higher prevalence of overweight/obesity compared to controls. Future studies are warranted to raise awareness of weight issues in FAP and determine the effect of weight loss on FAP.

Differences in Fecal Microbiomes and Metabolomes of People With vs Without Irritable Bowel Syndrome and Bile Acid Malabsorption

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a heterogeneous disorder, but diagnoses and determination of subtypes are made based on symptoms. We profiled the fecal microbiomes of patients with and without IBS to identify biomarkers of this disorder.

METHODS

We collected fecal and urine samples from 80 patients with IBS (Rome IV criteria; 16-70 years old) and 65 matched individuals without IBS (control individuals), along with anthropometric, medical, and dietary information. Shotgun and 16S ribosomal RNA amplicon sequencing were performed on feces, whereas urine and fecal metabolites were analyzed by gas chromatography and liquid chromatography-mass spectrometry. Co-occurrence networks were generated based on significant Spearman correlations between data. Bile acid malabsorption (BAM) was identified in patients with diarrhea by retention of radiolabeled selenium-75 homocholic acid taurine.

RESULTS

Patients with IBS had significant differences in network connections between diet and fecal microbiomes compared with control individuals; these were accompanied by differences in fecal metabolomes. We did not find significant differences in fecal microbiota composition among patients with different IBS symptom subtypes. Fecal metabolome profiles could discriminate patients with IBS from control individuals. Urine metabolomes also differed significantly between patients with IBS and control individuals, but most discriminatory metabolites were related to diet or medications. Fecal metabolomes, but not microbiomes, could distinguish patients with IBS with vs those without BAM.

CONCLUSIONS

Despite the heterogeneity of IBS, patients have significant differences in urine and fecal metabolomes and fecal microbiome vs control individuals, independent of symptom-based subtypes of IBS. Fecal metabolome analysis can be used to distinguish patients with IBS with vs those without BAM. These findings might be used for developing microbe-based treatments for these disorders.

Therapies to modulate gut microbiota: Past, present and future

The human gut microbiota comprises of a complex and diverse array of microorganisms, and over the years the interaction between human diseases and the gut microbiota has become a subject of growing interest. Disturbed microbial milieu in the gastrointestinal tract is central to the pathogenesis of several diseases including antibiotic-associated diarrhea and Clostridioides difficile infection (CDI). Manipulation of this microbial milieu to restore balance by microbial replacement therapies has proven to be a safe and effective treatment for recurrent CDI. There is considerable heterogeneity in various aspects of stool processing and administration for fecal microbiota transplantation (FMT) across different centers globally, and standardized microbioal replacement therapies offer an attractive alternative. The adverse effects associated with FMT are usually mild. However, there is paucity of data on long term safety of FMT and there is a need for further studies in this regard. With our increasing understanding of the host-microbiome interaction, there is immense potential for microbial replacement therapies to emerge as a treatment option for several diseases. The role of microbioal replacement therapies in diseases other than CDI is being extensively studied in ongoing clinical trials and it may be a potential treatment option for inflammatory bowel disease, irritable bowel syndrome, obesity, multidrug resistant infections, and neuropsychiatric illnesses. Fecal microbiota transplantation for non-CDI disease states should currently be limited only to research settings.

Microbial dysbiosis in irritable bowel syndrome: A single-center metagenomic study in Saudi Arabia

Background

The focus of this study was to explore potential differences in colonic mucosal microbiota in irritable bowel syndrome (IBS) patients compared to a control group utilizing a metagenomic study.

Methods

Mucosal microbiota samples were collected from each IBS patient utilizing jet‐flushing colonic mucosa in unified segments of the colon with distilled water, followed by aspiration, during colonoscopy. All the purified dsDNA was extracted and quantified before metagenomic sequencing using an Illumina platform. An equal number of healthy age‐matched controls were also examined for colonic mucosal microbiota, which were obtained during screening colonoscopies.

Results

The microbiota data on 50 IBS patients (31 females), with a mean age 43.94 ± 14.50 (range19–65), were analyzed in comparison to 50 controls. Satisfactory DNA samples were subjected to metagenomics study, followed by comprehensive comparative phylogenetic analysis. Metagenomics analysis was carried out, and 3.58G reads were sequenced. Community richness (Chao) and microbial structure in IBS patients were shown to be significantly different from those in the control group. Enrichment of Oxalobacter formigenes, Sutterella wadsworthensis, and Bacteroides pectinophilus was significantly observed in controls, whereas enrichment of Collinsella aerofaciens, Gemella morbillorum, and Veillonella parvula Actinobacteria was observed significantly in the IBS cohort.

Conclusion

The current study has demonstrated significant differences in the microbiota of IBS patients compared to controls.

Food Sensitivity Testing and Elimination Diets in the Management of Irritable Bowel Syndrome

The nonpharmacologic management of irritable bowel syndrome focuses on dietary modification through the concept of food sensitivity or intolerance. Currently, testing for food allergies is not recommended in the absence of a clinical history consistent with an immunoglobulin E–mediated reaction. Objective means of determining food sensitivity, such as individualized diets, are being studied, but testing for food sensitivity is limited to certain food groups. Diets such as the low-FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet may provide benefit.

Painful interactions: Microbial compounds and visceral pain

Visceral pain, characterized by abdominal discomfort, originates from organs in the abdominal cavity and is a characteristic symptom in patients suffering from irritable bowel syndrome, vulvodynia or interstitial cystitis. Most organs in which visceral pain originates are in contact with the external milieu and continuously exposed to microbes. In order to maintain homeostasis and prevent infections, the immune- and nervous system in these organs cooperate to sense and eliminate (harmful) microbes. Recognition of microbial components or products by receptors expressed on cells from the immune and nervous system can activate immune responses but may also cause pain. We review the microbial compounds and their receptors that could be involved in visceral pain development.

The Potential Role of Gut Mycobiome in Irritable Bowel Syndrome

The human gut is inhabited by diverse microorganisms that play crucial roles in health and disease. Gut microbiota dysbiosis is increasingly considered as a vital factor in the etiopathogenesis of irritable bowel syndrome (IBS), which is a common functional gastrointestinal disorder with a high incidence all over the world. However, investigations to date are primarily directed to the bacterial community, and the gut mycobiome, another fundamental part of gut ecosystem, has been underestimated. Intestinal fungi have important effects on maintaining gut homeostasis just as bacterial species. In the present article, we reviewed the potential roles of gut mycobiome in the pathogenesis of IBS and the connections between the fungi and existing mechanisms such as chronic low-grade inflammation, visceral hypersensitivity, and brain-gut interactions. Moreover, possible strategies targeted at the gut mycobiome for managing IBS were also described. This review provides a basis for considering the role of the mycobiome in IBS and offers novel treatment strategies for IBS patients; moreover, it adds new dimensions to researches on microorganism.

An Overview and Proposed Research Framework for Studying Co-Occurring Mental- and Physical-Health Dysfunction

Mental- and physical-health conditions co-occur at a rate much higher than chance. Of patients who have a mental-health condition, more than half also have a physical disease, and these cases are associated with increased human suffering and societal cost. Comorbidity research to date has focused on co-occurring mental- and physical-health disorders separately, and relatively little research has examined the co-occurrence of mental- and physical-health dysfunction. In addition, even less is known about why mental- and physical-health dysfunction co-occurs or how to treat these cases. Thus, the aims of this article are to highlight the need for research at the intersection of physical- and mental-health dysfunction and to provide guidance on how to research cases of comorbidity. Toward these ends, we begin by presenting a selective overview of the possible role of biological processes in the co-occurrence of physical- and mental-health dysfunction using specific illustrative examples. Specifically, we outline how biological processes within the immune system and gastrointestinal system could underlie depression, irritable bowel syndrome, and their co-occurrence. We then advance and discuss a proposed research framework, including methodological and analytic guidance, that researchers could use when studying the phenomenon of co-occurring physical- and mental-health dysfunction.

The Microbiome and Irritable Bowel Syndrome - A Review on the Pathophysiology, Current Research and Future Therapy

Irritable bowel syndrome (IBS) is a functional disorder which affects a large proportion of the population globally. The precise etiology of IBS is still unknown, although consensus understanding proposes IBS to be of multifactorial origin with yet undefined subtypes. Genetic and epigenetic factors, stress-related nervous and endocrine systems, immune dysregulation and the brain-gut axis seem to be contributing factors that predispose individuals to IBS. In addition to food hypersensitivity, toxins and adverse life events, chronic infections and dysbiotic gut microbiota have been suggested to trigger IBS symptoms in tandem with the predisposing factors. This review will summarize the pathophysiology of IBS and the role of gut microbiota in relation to IBS. Current methodologies for microbiome studies in IBS such as genome sequencing, metagenomics, culturomics and animal models will be discussed. The myriad of therapy options such as immunoglobulins (immune-based therapy), probiotics and prebiotics, dietary modifications including FODMAP restriction diet and gluten-free diet, as well as fecal transplantation will be reviewed. Finally this review will highlight future directions in IBS therapy research, including identification of new molecular targets, application of 3-D gut model, gut-on-a-chip and personalized therapy.

Evidence for an association of gut microbial Clostridia with brain functional connectivity and gastrointestinal sensorimotor function in patients with irritable bowel syndrome, based on tripartite network analysis

BACKGROUND AND AIMS

Evidence from preclinical and clinical studies suggests that interactions among the brain, gut, and microbiota may affect the pathophysiology of irritable bowel syndrome (IBS). As disruptions in central and peripheral serotonergic signaling pathways have been found in patients with IBS, we explored the hypothesis that the abundance of serotonin-modulating microbes of the order Clostridiales is associated with functional connectivity of somatosensory brain regions and gastrointestinal (GI) sensorimotor function.

METHODS

We performed a prospective study of 65 patients with IBS and 21 healthy individuals (controls) recruited from 2011 through 2013 at a secondary/tertiary care outpatient clinic in Sweden. Study participants underwent functional brain imaging, rectal balloon distension, a nutrient and lactulose challenge test, and assessment of oroanal transit time within a month. They also submitted stool samples, which were analyzed by 16S ribosomal RNA gene sequencing. A tripartite network analysis based on graph theory was used to investigate the interactions among bacteria in the order Clostridiales, connectivity of brain regions in the somatosensory network, and GI sensorimotor function.

RESULTS

We found associations between GI sensorimotor function and gut microbes in stool samples from controls, but not in samples from IBS patients. The largest differences between controls and patients with IBS were observed in the Lachnospiraceae incertae sedis, Clostridium XIVa, and Coprococcus subnetworks. We found connectivity of subcortical (thalamus, caudate, and putamen) and cortical (primary and secondary somatosensory cortices) regions to be involved in mediating interactions among these networks.

CONCLUSIONS

In a comparison of patients with IBS and controls, we observed disruptions in the interactions between the brain, gut, and gut microbial metabolites in patients with IBS-these involve mainly subcortical but also cortical regions of brain. These disruptions may contribute to altered perception of pain in patients with IBS and may be mediated by microbial modulation of the gut serotonergic system.

Is the Impact of Starvation on the Gut Microbiota Specific or Unspecific to Anorexia Nervosa? A Narrative Review Based on a Systematic Literature Search

Background:

The role of the gut microbiota in Anorexia Nervosa (AN) has long been neglected by researchers, although the fact that the former is known to play an important role in health, disease and weight regulation. Cycles of over-weight and underweight due to natural states of starvation and refeeding are normal in many vertebrates in their ecological niches.

Objective:

The aim of this review was to compare the similarities and differences of the gut microbiota in eating disorders with conditions of fasting and refeeding in other vertebrates.

Method:

A systematic literature search was conducted in Pubmed and Web of Science to find all relevant studies examining the gut microbiota in eating disorders and different states of fasting in vertebrates for this narrative review.

Results:

Gut microbiota appears to differ in AN versus normal-weight individuals. Induced fasting conditions in other ver-tebrates resulted in heterogeneous effects on gut microbiota with respect to their richness, diversity and community struc-tures. The findings for hibernating animals were generally consistent. A decrease in microbial richness and diversity was ob-served in the hibernating animal compared to the active animal, and the community structures were linked to these conditions. Some similarities and differences between AN and different states of fasting in other vertebrates were found.

Conclusion:

The complexity of the relationship between fasting and gut microbiota is difficult to interprete. A deeper bio-logical understanding is necessary to identify promising approaches for the modulation of the AN gut microbiota to support established psychotherapies

Pharmacokinetic drug evaluation of rifaximin for treatment of diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Rifaximin is a poorly absorbable antibiotic with a broad-spectrum activity against both Gram-negative and -positive bacteria. It is active in the small intestine due to its high bile solubility, whereas in the aqueous environment of the colon, it shows limited efficacy against highly susceptible bacteria. These unique pharmacokinetic properties limit its systemic effects and can correct gut microflora imbalances. Thus, rifaximin has become a major therapeutic agent in several gastrointestinal diseases in which an imbalance in gut microflora may play a role, including diarrhea predominant irritable bowel syndrome (IBS-D). Area covered: This is an up-to-date review focusing on the efficacy of rifaximin in the treatment of IBS-D in both adult and pediatric populations. We will review the pharmacokinetic properties of rifaximin, including its absorption in health and disease, mechanisms of action, and interactions with other drugs. Expert opinion: Given its safety profile and its negligible absorption, rifaximin is a suitable treatment for IBS-D, in both adults and children. The possibility of modulating gut microbiota composition without side effects has made this drug an appealing therapeutic agent in highly prevalent gastrointestinal diseases. However, to date, monitoring for the development of resistant bacterial strains during long-term rifaximin use is still lacking.

Blastocystis subtypes and their association with Irritable Bowel Syndrome

Blastocystis spp. is a common intestinal protozoan that affects humans and animals. The role of this parasite as a pathogen is still controversial and it is suspected to be linked to Irritable Bowel Syndrome (IBS), a functional bowel disorder characterized by chronic or recurrent abdominal pain associated with altered intestinal habits. A broad search in electronic databases, libraries, portals of journals, etc. for reports on the association between the parasite and IBS without language restriction was performed. The selection was not restricted by date, but articles published in the last seven years were given preference. We investigated the evidence regarding Blastocystis and IBS coexistence as well as the implications of the parasite in pathogenesis and clinical manifestations. Only standardized parasitological tools, supplemented by epidemiological analysis, will be able to clarify whether parasite carriage could be connected to IBS and its status as a human pathogen. Although a variation in pathogenicity and virulence between subtypes has been confirmed, Blastocystis can only be considered an indicator of dysbiosis. Accurate diagnoses of this parasitic eukaryote, specifically at genotypic and phenotypic levels, as well as the complete analysis of the intestinal microbial communities, have to be included in the protocol of those patients with IBS.

Irritable bowel syndrome - from etiopathogenesis to therapy

Irritable bowel syndrome (IBS) is a chronic and relapsing functional gastrointestinal disorder that affects 9-23% of the population across the world. Patients with IBS are often referred to gastroenterology, undergo various investigations, take various medicines, take time off work and have a poor quality of life. The pathophysiology of IBS is not yet completely understood and seems to be multifactorial. Many pathogenetic factors, in various combinations, and not all necessarily present in each patient, can play an important role. Discomfort or abdominal pain relieived by defacation, asociated with a change in stool form, is a typical clinical manifestation of IBS. Many factors, such as emotional stress and eating, may exacerbate the symptoms. A timely diagnosis of IBS is important so that treatment which will provide adequate symptomatic relief (diarrhoea, constipation, pain and boaring) can be introduced. The diagnosis of IBS is not confirmed by a specific test or structural abnormality. It is made using criteria based on clinical symptoms such as Rome criteria, unless the symptoms are thought to be atypical. Today the Rome Criteria IV is the current gold-standard for the diagnoses of IBS. Treatment of patients with IBS requires a multidisciplinary approach. Some patients respond well to non-pharmacological treatment, while others also require pharmacological treatment. This review will provide a summary of pathophysiology, diagnostic criteria and therapies for IBS.

Probiotics in Functional Gastrointestinal Disorders

Infantile colic, constipation, functional abdominal pain (FAP), and irritable bowel syndrome (IBS) are the most common functional gastrointestinal disorders (FGID). This chapter will review current evidence on the role of probiotics in the treatment of these FGID. The etiology of FGID is considered multifactorial, but the importance of intestinal microbiota in their development has been repeatedly emphasized. As a consequence, the potential role of probiotics in their treatment is being increasingly scrutinized. Presently, the strongest evidence of efficacy is for the use of Lactobacillus reuteri (L reuteri) DSM 17938 at the dose of 10⁸ CFU/day for the treatment of infantile colic in breastfed infants. Limited, yet encouraging, evidence exists for Lactobacillus rhamnosus GG (LGG) at the dose of 3 × 10⁹ CFU and for a multi-strain preparation for the treatment of IBS. In the treatment of FAP, there is some evidence for the use of L reuteri DSM 17938 at the dose of at least 10⁸ CFU/day.

Microbiota Replacement Therapies: Innovation in Gastrointestinal Care

There has been an increasing interest in the association between human disease and altered gut microbiota, and therapeutics to modulate microbiota to treat disease. Healthy human gastrointestinal microbiota is highly diverse and rich, and harbors between 500 and 2,000 species. Diseases associated with dysbiotic microbiota include antibiotic-associated diarrhea, Clostridium difficile infection, multidrug-resistant organisms, inflammatory bowel disease, obesity, metabolic syndrome, diabetes mellitus, neuropsychiatric diseases, and systemic autoimmune diseases. Microbiota replacement therapies have shown immense promise in treatment of recurrent C. difficile infection and are being studied for other indications. Microbiota replacement therapies for indications other than C. difficile infection should be performed only in research settings. There is an immense need for standardized microbiota replacement therapies for C. difficile infection. Studies are needed to elucidate long-term safety and adverse events from these therapies.

Post-Resection Exhaustion of Intra-Platelet Serotonin: Also an Indicator of Early Hepatocellular Carcinoma Recurrence?

Purpose: Serotonin (5-hydroxytryptamine, 5-HT) is well known for its growth stimulatory effect on several types of carcinoma and tumor cells. Since a large portion of 5-HT is stored and transported by platelets, the aim of this study was to assess the influence of platelet-sequestered 5-HT on post-resection hepatocellular carcinoma (HCC) recurrence.

Methods: This pilot study was conducted in a cohort of forty patients diagnosed with HCC undergoing partial hepatectomy. 5-HT levels in serum, plasma and intra-platelet (IP) were monitored preoperatively and four weeks after liver resection. The patients were followed every three months after the surgery.

Results: Follow-up was standardized to a fixed length of time. Fifteen patients (37.5%) developed HCC recurrence during 18 months follow-up. Patients with recurrence had significantly reduced serum and IP 5-HT levels at four weeks of liver resection (P = 0.003 and P = 0.014 respectively). Accordingly, in the Cox regression hazard model, serum and IP 5-HT were able to independently predict the recurrence (hazard ratio = 0.1, 95% confidence interval = 0.01 - 0.75 and hazard ratio = 0.1, 95% confidence interval = 0.01 - 0.89 respectively). The optimal cut-off value of 42.77 ng/ml for serum [area under the curve (AUC): 0.78, P = 0.003] and 0.3117 ng per 10⁶ platelets (AUC: 0.733, P = 0.015), on receiver operating characteristic (ROC) curve corresponded to maximum sensitivity and specificity of prediction. The disease free interval was significantly worse in patients with low serum and IP 5-HT (P = 0.001 and P = 0.029 respectively).

Conclusion: IP 5-HT monitored during early follow-up, after liver resection may represent a useful marker of early HCC recurrence.

Vasoactive Intestinal Polypeptide and Mast Cells Regulate Increased Passage of Colonic Bacteria in Patients With Irritable Bowel Syndrome

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is associated with intestinal dysbiosis and symptoms of IBS develop following gastroenteritis. We aimed to study the passage of live bacteria through the colonic epithelium, and determine the role of mast cells (MCs) and vasoactive intestinal polypeptide (VIP) in barrier regulation in IBS and healthy individuals.

METHODS

Colon biopsies from 32 women with IBS and 15 age-matched healthy women (controls) were mounted in Ussing chambers; we measured numbers of fluorescently labeled Escherichia coli HS and Salmonella typhimurium that passed through from the mucosal side to the serosal side of the tissue. Some biopsies were exposed to agents that block the VIP receptors (VPAC1 and VPAC2) or MCs. Levels of VIP and tryptase were measured in plasma and biopsy lysates. Number of MCs and MCs that express VIP or VIP receptors were quantified by immunofluorescence. Biopsies from an additional 5 patients with IBS and 4 controls were mounted in chambers and Salmonella were added; we studied passage routes through the epithelium by transmission electron microscopy and expression of tight junctions by confocal microscopy.

RESULTS

In colon biopsies from patients with IBS, larger numbers of E coli HS and S typhimurium passed through the epithelium than in biopsies from controls (P < .0005). In transmission electron microscopy analyses, bacteria were found to cross the epithelium via only the transcellular route. Bacterial passage was reduced in biopsies from patients with IBS and controls after addition of antibodies against VPACs or ketotifen, which inhibits MCs. Plasma samples from patients with IBS had higher levels of VIP than plasma samples from controls. Biopsies from patients with IBS had higher levels of tryptase, larger numbers of MCs, and a higher percentage of MCs that express VPAC1 than biopsies from controls. In biopsies from patients with IBS, addition of Salmonella significantly reduced levels of occludin; subsequent addition of ketotifen significantly reversed this effect.

CONCLUSIONS

We found that colonic epithelium tissues from patients with IBS have increased translocation of commensal and pathogenic live bacteria compared with controls. The mechanisms of increased translocation include MCs and VIP.

Prevalence and predictors of irritable bowel syndrome in patients with morbid obesity: a cross-sectional study

BACKGROUND

Irritable bowel syndrome has been reported as more common in patients with morbid obesity than in the general population. The reason for this association is unknown. The aims of this study were to study the prevalence of irritable bowel syndrome and other functional bowel disorders in patients with morbid obesity, and to search for predictors of irritable bowel syndrome.

METHODS

Patients opting for bariatric surgery at two obesity centers in South-Eastern Norway were included. Functional bowel disorders were diagnosed according to the Rome III criteria. Predictors were evaluated in a multivariable logistic regression analysis with irritable bowel syndrome as the dependent variable.

RESULTS

A total of 350 (58%) out of 603 consecutive patients were included. The prevalence rates of irritable bowel syndrome at the two centers were 17/211 (8%) and 37/139 (27%) respectively. High low-density lipoprotein (OR 2.10; 95% CI 1.34-3.29), self-reported psychiatric disorders (OR 2.39; 95% CI 1.12-5.08) and center (OR 5.22; 95% CI 2.48-10.99) were independent predictors of irritable bowel syndrome.

CONCLUSIONS

At one of the two obesity centers, the prevalence of irritable bowel syndrome was threefold higher than in the general population in the same region. The high prevalence appears to be related to dietary differences or altered absorption or metabolism of fat. Attention to irritable bowel syndrome is important in the care of patients with morbid obesity.

Dientamoeba fragilis colonization is not associated with gastrointestinal symptoms in children at primary care level

BACKGROUND

Dientamoeba fragilis is commonly identified in children in primary care and is suspected to cause gastrointestinal disease.

OBJECTIVE

To determine the association between D. fragilis colonization and gastrointestinal symptoms in children.

METHODS

We performed a cross-sectional study with children who presented in primary care with gastrointestinal symptoms. The associations between D. fragilis colonization and specific symptoms were explored by means of logistic regression analyses. Asymptomatic siblings of these cases were invited as control subjects for a case-control analysis, where we explored the association between D. fragilis and gastrointestinal symptoms with conditional logistic regression analysis.

RESULTS

In the cross-sectional study, 107 children were included. Their median age was 9 years (interquartile range = 6-12) and 38 (35.5%) were boys. Colonization of D. fragilis was present in 59 children (55.1%). The absence of D. fragilis was associated with soft to watery stool [odds ratio (OR) = 0.29; 95% confidence interval (CI) = 0.10-0.85], chronic diarrhoea (OR = 0.42; 95% CI = 0.18-0.97) and fatigue (OR = 0.45; 95% CI = 0.20-0.99). The case-control analyses included 44 children in each group. Dientamoeba fragilis colonization was not observed more often in cases than in controls after adjustment for age and sex (OR = 1.02; 95% CI = 0.28-3.65).

CONCLUSION

Dientamoeba fragilis is a common parasite in children with and without gastrointestinal symptoms. The anomalous finding of the association between the absence of D. fragilis with soft to watery stools, chronic diarrhoea and fatigue are inexplicable. Our study suggests that D. fragilis colonization does not increase the risk for gastrointestinal symptoms.

Identification of an Intestinal Microbiota Signature Associated With Severity of Irritable Bowel Syndrome

BACKGROUND & AIMS

We have limited knowledge about the association between the composition of the intestinal microbiota and clinical features of irritable bowel syndrome (IBS). We collected information on the fecal and mucosa-associated microbiota of patients with IBS and evaluated whether these were associated with symptoms.

METHODS

We collected fecal and mucosal samples from adult patients who met the Rome III criteria for IBS at a secondary/tertiary care outpatient clinics in Sweden, as well as from healthy subjects. The exploratory set comprised 149 subjects (110 with IBS and 39 healthy subjects); 232 fecal samples and 59 mucosal biopsy samples were collected and analyzed by 16S ribosomal RNA targeted pyrosequencing. The validation set comprised 46 subjects (29 with IBS and 17 healthy subjects); 46 fecal samples, but no mucosal samples, were collected and analyzed. For each subject, we measured exhaled H₂ and CH₄, oro-anal transit time, and the severity of psychological and gastrointestinal symptoms. Fecal methanogens were measured by quantitative polymerase chain reaction. Numerical ecology analyses and a machine learning procedure were used to analyze the data.

RESULTS

Fecal microbiota showed covariation with mucosal adherent microbiota. By using classic approaches, we found no differences in fecal microbiota abundance or composition between patients with IBS vs healthy patients. A machine learning procedure, a computational statistical technique, allowed us to reduce the 16S ribosomal RNA data complexity into a microbial signature for severe IBS, consisting of 90 bacterial operational taxonomic units. We confirmed the robustness of the intestinal microbial signature for severe IBS in the validation set. The signature was able to discriminate between patients with severe symptoms, patients with mild/moderate symptoms, and healthy subjects. By using this intestinal microbiota signature, we found IBS symptom severity to be associated negatively with microbial richness, exhaled CH₄, presence of methanogens, and enterotypes enriched with Clostridiales or Prevotella species. This microbiota signature could not be explained by differences in diet or use of medications.

CONCLUSIONS

In analyzing fecal and mucosal microbiota from patients with IBS and healthy individuals, we identified an intestinal microbiota profile that is associated with the severity of IBS symptoms.

TRIAL REGISTRATION NUMBER

NCT01252550.