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

Gut microbial dysbiosis associated to diarrheic irritable bowel syndrome can be efficiently simulated in the Mucosal ARtificial COLon (M-ARCOL)

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder, with diarrhea-predominant IBS (IBS-D) as the most frequent subtype. The implication of gut microbiota in the disease's etiology is not fully understood. In vitro gut systems can offer a great alternative to in vivo assays in preclinical studies, but no model reproducing IBS-related dysbiotic microbiota has been developed. Thanks to a large literature review, a new Mucosal ARtifical COLon (M-ARCOL) adapted to IBS-D physicochemical and nutritional conditions was set-up. To validate the model and further exploit its potential in a mechanistic study, in vitro fermentations were performed using bioreactors inoculated with stools from healthy individuals (n = 4) or IBS-D patients (n = 4), when the M-ARCOL was set-up under healthy or IBS-D conditions. Setting IBS-D parameters in M-ARCOL inoculated with IBS-D stools maintained the key microbial features associated to the disease in vivo, validating the new system. In particular, compared to the healthy control, the IBS-D model was characterized by a decreased bacterial diversity, together with a lower abundance of Rikenellaceae and Prevotellaceae, but a higher level of Proteobacteria and Akkermansiaceae. Of interest, applying IBS-D parameters to healthy stools was not sufficient to trigger IBS-D dysbiosis and applying healthy parameters to IBS-D stools was not enough to restore microbial balance. This validated IBS-D colonic model can be used as a robust in vitro platform for studies focusing on gut microbes in the absence of the host, as well as for testing food and microbiota-related interventions aimed at personalized restoration of gut microbiota eubiosis.

Microbial Influences on Irritable Bowel Syndrome

Since the description of postinfection irritable bowel syndrome (IBS), a role for gut microbes in the pathogenesis of IBS has been proposed. Molecular microbiological tools have now been applied to IBS, though data are largely derived from fecal samples with attendant limitations. Metagenomics, metabolomics, and other 'omics facilitate a comprehensive picture of the microbiome and its metabolic activity. Has a microbial signature characteristic of IBS been identified? The answer is no; this should not be a surprise given the heterogeneity of the phenotype and each individual's microbiome profile.

Microbiota-neuroepithelial signalling across the gut-brain axis

Research over the past two decades has established a remarkable ability of the gut microbiota to modulate brain activity and behaviour. Conversely, signals from the brain can influence the composition and function of the gut microbiota. This bidirectional communication across the gut microbiota-brain axis, involving multiple biochemical and cellular mediators, is recognized as a major brain-body network that integrates cues from the environment and the body's internal state. Central to this network is the gut sensory system, formed by intimate connections between chemosensory epithelial cells and sensory nerve fibres, that conveys interoceptive signals to the central nervous system. In this Review, we provide a broad overview of the pathways that connect the gut and the brain, and explore the complex dialogue between microorganisms and neurons at this emerging intestinal neuroepithelial interface. We highlight relevant microbial factors, endocrine cells and neural mechanisms that govern gut microbiota-brain interactions and their implications for gastrointestinal and neuropsychiatric health.

The biomedical applications of artificial intelligence: an overview of decades of research

A significant area of computer science called artificial intelligence (AI) is successfully applied to the analysis of intricate biological data and the extraction of substantial associations from datasets for a variety of biomedical uses. AI has attracted significant interest in biomedical research due to its features: (i) better patient care through early diagnosis and detection; (ii) enhanced workflow; (iii) lowering medical errors; (v) lowering medical costs; (vi) reducing morbidity and mortality; (vii) enhancing performance; (viii) enhancing precision; and (ix) time efficiency. Quantitative metrics are crucial for evaluating AI implementations, providing insights, enabling informed decisions, and measuring the impact of AI-driven initiatives, thereby enhancing transparency, accountability, and overall impact. The implementation of AI in biomedical fields faces challenges such as ethical and privacy concerns, lack of awareness, technology unreliability, and professional liability. A brief discussion is given of the AI techniques, which include Virtual screening (VS), DL, ML, Hidden Markov models (HMMs), Neural networks (NNs), Generative models (GMs), Molecular dynamics (MD), and Structure-activity relationship (SAR) models. The study explores the application of AI in biomedical fields, highlighting its enhanced predictive accuracy, treatment efficacy, diagnostic efficiency, faster decision-making, personalised treatment strategies, and precise medical interventions.

Associations Among Diet, Health, Lifestyle, and Gut Microbiota Composition in the General French Population: Protocol for the Le French Gut - Le Microbiote Français Study

BACKGROUND

Over the past 2 decades, the gut microbiota has emerged as a key player in human health, being involved in many different clinical contexts. Yet, many aspects of the relationship with its host are poorly documented. One obstacle is the substantial variability in wet-laboratory procedures and data processing implemented during gut microbiota studies, which poses a challenge of comparability and potential meta-analysis.

OBJECTIVE

The study protocol described here aimed to better understand the relationship between health, dietary habits, and the observed heterogeneity of gut microbiota composition in the general population. "Le French Gut - Le microbiote français" aimed to collect, sequence, and analyze 100,000 fecal samples from French residents using a high-quality shotgun metagenomic pipeline, complemented with comprehensive health, lifestyle, and dietary metadata.

METHODS

"Le French Gut - Le microbiote français" is a prospective, noninterventional French national study involving individuals, the creation of a biological collection (feces), and the exploitation of data from questionnaires and the National Health Data System (Système National des Données de Santé). This national study is open to all metropolitan French adult residents, excluding those who have undergone a colectomy or digestive stoma, or who have had a colonoscopy or taken antibiotics in the last 3 months. This is a home-based trial in which volunteers complete a questionnaire with insights about their health and habits, and in which stool samples are self-collected. Data analysis is structured into 6 work packages, each focusing on a specific aspect of the gut microbiome, including its composition and associations with lifestyle, quality of life, and health.

RESULTS

This paper outlines the study protocol, with recruitment having started in September 2022 and expected to continue until the end of December 2025. As of January 2025, a total of 20,000 participants have been enrolled. The first scientific publications based on the data analysis are expected by mid-2025.

CONCLUSIONS

"Le French Gut" aims to provide a reference database and new ecosystem tools for understanding the relationship between the gut microbiota, its host, and diet. We expect to be able to find new signatures or targets and promote the design of innovative preventive strategies, personalized nutrition, and precision medicine.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05758961; https://clinicaltrials.gov/study/NCT05758961.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/64894.

Sex differences in the association between long-term ambient particulate air pollution and the intestinal microbiome composition of children

The intestinal microbiome is essential for gastrointestinal and overall health, yet its response to air pollution in children remains underexplored. In a study involving 412 young children from the ENVIRONAGE cohort, stool samples were analysed via Illumina Miseq sequencing to assess microbiome alpha diversity (observed richness, species evenness, and Shannon diversity) and composition. Exposure to previous year particulate air pollution (black carbon, PM2.5, coarse PM, and PM10) was modeled using high-resolution spatial-temporal interpolation models. Multiple linear regression models were adjusted for a priori selected covariables and stratified by sex. Furthermore, we performed a differential relative abundance analysis at family and genus level, while accounting for the same covariables. Statistically significant effect modification by sex was apparent for several intestinal alpha diversity indices and air pollutants. In boys, we observed negative associations between particulate air pollution exposure and intestinal microbiome richness (estimates ranging from -5.55 to -9.06 per interquartile range (IQR) increase in particulate air pollution exposure) and Shannon diversity (estimates ranging from -0.058 to -0.095 per IQR increase). Differently, in girls non-significant positive associations were observed with species evenness (estimates ranging from 0.019 to 0.020 per IQR increase) and Shannon diversity (estimate 0.065 per IQR increase in black carbon). After multiple testing correction, we reported several bacterial families and genera (Streptococcaceae, Clostridiales Incertae Sedis XIII, Coriobacteriaceae, Streptococcus, and Paraprevotella) to be oppositely associated with particulate air pollution exposure in boys and girls. Our findings show a sex-dependent association between particulate air pollution exposure and intestinal microbiome composition, highlighting boys as potentially more vulnerable to diversity loss associated with childhood exposure to particulate pollution.

Efficient extraction of pectin from spaghetti squash (Cucurbita pepo L. subsp. pepo) peel by electron beam irradiation combined with ultrasound: Structural characterization and functional properties

This study investigated the effects of acid extraction, electron beam irradiation (EBI) extraction, ultrasound extraction, and combined EBI and ultrasound extraction on the yield, structure, and functional properties of pectin from spaghetti squash (Cucurbita pepo L. subsp. pepo) peel. The established extraction kinetics model indicated that the combined EBI and ultrasound extraction exhibited a synergistic effect, resulting in a pectin yield (13.50 %) higher than that obtained from acid extraction (6.55 %), EBI extraction (10.91 %), and ultrasound extraction (7.56 %). The pectin produced through the combined method (EUSP) demonstrated a low degree of esterification (DE) (34.77 %) and molecular weight (Mw) of 83 kDa. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that EBI and ultrasound significantly disrupted the internal structure of the pectin. Rheological analysis indicated that the combined treatment reduced the viscosity characteristics of the pectin solution. EUSP exhibited good thermodynamic properties, emulsifying characteristics, antioxidant activities, and prebiotic activity. These findings provide a theoretical basis for the combined EBI and ultrasound extraction of pectin and offer insights for the efficient utilization of spaghetti squash peel and the application of pectin in the food industry.

Causal Analysis Between Gut Microbes, Aging Indicator, and Age-Related Disease, Involving the Discovery and Validation of Biomarkers

The influence of gut microbes on aging has been reported in several studies, but the mediating pathways of gut microbiota, whether there is a causal relationship between the two, and biomarker screening and validation have not been fully discussed. In this study, Mendelian Randomization (MR) and Linkage Disequilibrium Score Regression (LDSC) are used to systematically investigate the associations between gut microbiota, three aging indicators, and 14 age-related diseases. Additionally, this study integrates machine learning algorithms to explore the potential of MR and LDSC methods for biomarker screening. Gut microbiota is found to be a potential risk factor for 14 age-related diseases. The causal effects of gut microbiota on chronic kidney disease, cirrhosis, and heart failure are partially mediated by aging indicators. Additionally, gut microbiota identified through MR and LDSC methods exhibit biomarker properties for disease prediction (average AUC = 0.731). These methods can serve as auxiliary tools for conventional biomarker screening, effectively enhancing the performance of disease models (average AUC increased from 0.808 to 0.832). This study provides evidence that supports the association between the gut microbiota and aging and highlights the potential of genetic correlation and causal relationship analysis in biomarker discovery. These findings may help to develop new approaches for healthy aging detection and intervention.

Impact of Artificial Intelligence on Clinical Research

Artificial intelligence (AI) has potential to significantly impact clinical research when it comes to research preparation and data interpretation. Development of AI tools that can help in performing literature searches, synthesizing and streamlining data collection and analysis, and formatting of study could make the clinical research process more efficient. Several of these tools have been developed and trialed and many more are being rapidly developed. This article highlights the AI applications in clinical research in gastroenterology including its impact on drug discovery and explores areas where further guidance is needed to supplement the current understanding and enhance its use.

Human-derived microRNA 21 regulates indole and L-tryptophan biosynthesis transcripts in the gut commensal Bacteroides thetaiotaomicron

In the gut, microRNAs (miRNAs) produced by intestinal epithelial cells are secreted into the lumen and can shape the composition and function of the gut microbiome. Crosstalk between gut microbes and the host plays a key role in irritable bowel syndrome (IBS) and inflammatory bowel diseases, yet little is known about how the miRNA-gut microbiome axis contributes to the pathogenesis of these conditions. Here, we investigate the ability of miR-21, a miRNA that we found decreased in fecal samples from IBS patients, to associate with and regulate gut microbiome function. When incubated with the human fecal microbiota, miR-21 revealed a rapid internalization or binding to microbial cells, which varied in extent across different donor samples. Fluorescence-activated cell sorting and sequencing of microbial cells incubated with fluorescently labeled miR-21 identified organisms belonging to the genera Bacteroides, Limosilactobacillus, Ruminococcus, or Coprococcus, which predominantly interacted with miR-21. Surprisingly, these and other genera also interacted with a miRNA scramble control, suggesting that physical interaction and/or uptake of these miRNAs by gut microbiota is not sequence-dependent. Nevertheless, transcriptomic analysis of the gut commensal Bacteroides thetaiotaomicron revealed a miRNA sequence-specific effect on bacterial transcript levels. Supplementation of miR-21, but not of small RNA controls, resulted in significantly altered levels of many cellular transcripts and increased transcription of a biosynthetic operon for indole and L-tryptophan, metabolites known to regulate host inflammation and colonic motility. Our study identifies a novel putative miR-21-dependent pathway of regulation of intestinal function through the gut microbiome with implications for gastrointestinal conditions.

IMPORTANCE

The mammalian gut represents one of the largest and most dynamic host-microbe interfaces. Host-derived microRNAs (miRNAs), released from the gut epithelium into the lumen, have emerged as important contributors to host-microbe crosstalk. Levels of several miRNAs are altered in the stool of patients with irritable bowel syndrome or inflammatory bowel disease. Understanding how miRNAs interact with and shape gut microbiota function is crucial as it may enable the development of new targeted treatments for intestinal diseases. This study provides evidence that the miRNA miR-21 can rapidly associate with diverse microbial cells form the gut and increase levels of transcripts involved in tryptophan synthesis in a ubiquitous gut microbe. Tryptophan catabolites regulate key functions, such as gut immune response or permeability. Therefore, this mechanism represents an unexpected host-microbe interaction and suggests that host-derived miR-21 may help regulate gut function via the gut microbiota.

Lacidophilin tablets relieve irritable bowel syndrome in rats by regulating gut microbiota dysbiosis and intestinal inflammation

Irritable bowel syndrome (IBS) is a common clinical functional gastrointestinal disease. It has a complex pathophysiological mechanism, in which the imbalance of gut microbiota might play an important role. Lacidophilin tablets (LH) can regulate gut microbiota, but their effect on IBS is unknown. In this study, the IBS model was established by acetic acid enema combined with the constrained stress method, and rats were fed LH for 2 weeks. LH significantly reduced visceral sensitivity and intestinal propulsion rate and improved IBS-induced anxiety and depressive behavior in IBS rats. LH elevated the expression levels of mucin 2, claudin1, and occludin, and ameliorated IBS-induced structural damage to colonic tissues. The gut microbiota analysis revealed that LH altered the structure and composition of the gut microbiota in IBS rats. In addition, LH reduced the expression levels of inflammatory factor-related genes. These results suggest that LH could significantly improve the visceral sensitivity and intestinal motility disorders of IBS rats, relieve anxiety and depression levels, and alleviate the symptoms of IBS rats by regulating gut microbiota and reducing intestinal inflammation.

Ex Vivo Analysis of the Effect of Endoscopic Premedications on the Microbiota Profile in Gastric Juice

Background and Aim

Dimethicone (GAS), lidocaine (XYL), and protease (PRO) are commonly used as premedications during esophagogastroduodenoscopy (EGD). However, the effects of these drugs on the gastric microbiota remain unexplored. Therefore, we aimed to investigate the effects of these premedications on gastric juice collected from patients undergoing EGD.

Methods

Gastric juice was endoscopically aspirated from six patients and divided into six aliquots for in vitro analysis. The samples were mixed with premedications in corresponding treatment sets: GAS, XYL, PRO, MIX (a mixture of GAS, XYL, and PRO), and control (CTL1 and 2; no medication treatment). After extraction of microbial DNA from the treated samples, the 16S rRNA amplicon sequence was analyzed to determine the microbiota profile in terms of (1) the amount of genomic DNA (gDNA), (2) α-diversity indices, Shannon index, number of observed operational taxonomic units (OTUs), and Chao1 index, (3) weighted and unweighted UniFrac distances, and (4) the relative abundance of phyla and genera.

Results

The total amount of extracted gDNA did not significantly differ between the six groups. The α-diversity indices did not significantly differ between treatment groups. Although GAS, PRO, and MIX differed significantly from the technical replicates in the weighted UniFrac distance (p = 0.03 all), no significant difference was observed in the unweighted UniFrac distance. However, significant differences were observed in the relative abundance of several bacterial microbiota at the phylum and genus levels.

Conclusions

Premedications affect the microbiota profile of specific phylum- and genus-level bacterial groups. Trial Registration: University Hospital Medical Information Network Clinical Trials Registry: UMIN-CTR 000040192 and UMIN-CTR 000051289.

Colonoscopic administration of probiotics to treat irritable bowel syndrome with predominant diarrhea: a randomized placebo-controlled clinical trial

BACKGROUND

To investigate the effects of colonoscopic administration of probiotics on patients with irritable bowel syndrome with predominant diarrhea (IBS-D) by a single-center, randomized-controlled trial.

METHODS

Consecutive outpatients at the First Affiliated Hospital of Fujian Medical University who met the Rome IV diagnostic criteria for IBS-D (n = 22) and healthy subjects (n = 10) from January 2017 to January 2018 were enrolled. IBS-D patients were randomly divided into either the probiotics or the placebo group. During the colonoscopy examination, a suspension of live combined Bifidobacterium with Lactobacillus tablets and normal saline was sprayed into the right colon of patients in the probiotics and the placebo group, respectively. All subjects' clinical data and stool samples were collected before, 2 weeks and 4 weeks after colonoscopic treatment.

RESULTS

Twenty-nine subjects completed the follow-up. A significant difference was found in the frequency of defecation at 2 weeks, and the abdominal Visual Analog Score and Bristol stool scale at 4 weeks after probiotics treatment. The gastrointestinal symptom rating scale and IBS severity score decreased significantly and the IBS Quality of Life Instrument score increased 2 weeks after probiotics treatment (p < 0.05). The comprehensive therapeutic index was 70.0% and 44.4% in the probiotics group and the placebo group, respectively. The gut microbiota diversity was not significantly different at 2 and 4 weeks after treatment among the groups. Ratio of Firmicutes to Bacteroidetes decreased in the probiotics group.

CONCLUSIONS

The symptoms of IBS-D could be improved by probiotics administration via colonoscopy. The study was registered on chictr.org.cn (ChiCTR-IPR-17010411).

Association of body roundness index with chronic diarrhea and constipation, NHANES 2005-2010

BACKGROUND

Chronic diarrhea and constipation are known to be associated with obesity. Body roundness index (BRI), as a novel physical dimension assessment indicator, provides a more comprehensive evaluation of body and visceral fat than traditional methods. However, the relationship between BRI, chronic diarrhea, and constipation remains unclear. We aimed to investigate the relationship between BRI, chronic diarrhea, and constipation.

METHODS

A cross-sectional study based on the National Health and Nutrition Examination Survey 2005-2010 was conducted. Weighted multivariable logistic regression was used to analyze the association between BRI, chronic diarrhea, and constipation. Restricted cubic spline curves were plotted to verify the linear associations.

RESULTS

7182 participants were included in this study, among whom 491 had chronic diarrhea and 441 had constipation. Significant positive correlations were discovered between BRI and chronic diarrhea, while no correlation was detected with constipation in the fully adjusted multivariable logistic regression analysis. Restricted cubic spline curves confirmed the linear relationship described above. Further treating BRI as categorical variables, compared with the lowest tertile, the highest BRI tertile showed a 79% increase in chronic diarrhea incidence and a 35% decrease in chronic constipation incidence. Consistent findings were observed across different subgroups, and sensitivity analyses generally confirmed the robustness of our results.

CONCLUSIONS

BRI is significantly and linearly associated with chronic diarrhea. Higher body and visceral fat increase the risk of chronic diarrhea while reducing the risk of chronic constipation.

Comparison of Rifaximin Monotherapy and Rifaximin Combined with Probiotics in Patients with Irritable Bowel Syndrome: A Randomized Controlled Trial

Background/Objective: Rifaximin is a nonabsorbable antibiotic used to treat irritable bowel syndrome (IBS). Recent studies on Helicobacter pylori eradication treatment have reported synergistic effects and low adverse effects when antibiotics are used in combination with probiotics; yet, such studies have not been conducted in IBS. Probiotics can enhance gut microbiota modulation, inhibition of pathogen adhesion to the gut epithelia, improvement in gut barrier function, anti-inflammatory effects, and improvement of gut immunity. Therefore, this study aimed to investigate the efficacy and safety of rifaximin in combination with probiotics compared to rifaximin monotherapy in patients with IBS. Methods: Patients with IBS were randomly allocated to receive rifaximin monotherapy or a combination of rifaximin and probiotics. The primary outcome was the response rate of the total IBS severity scoring system (IBS-SSS) score (>50-point decrease). Secondary outcomes were based on the response rate of the IBS quality of life (IBS-QOL) score and the IBS-SSS1 subscore (>10-point decrease in both scores). Results: Among 70 patients, the responder rates for the total IBS-SSS score were 65.7% in the combination therapy group and 31.4% in the monotherapy group at weeks 4 and 8, respectively (p = 0.004). The responder rates for IBS-QOL were 65.7% versus (vs.) 37.1% and 65.7% vs. 34.2% at weeks 4 and 8, respectively (p = 0.017 and p = 0.009, respectively). The IBS-SSS1 subscore responder rates were 65.7% vs. 40.0% at week 4 and 68.6% vs. 37.1% at 8 weeks (p = 0.031 and p = 0.017, respectively). Conclusions: Rifaximin combined with probiotics was superior to rifaximin monotherapy in patients with IBS. This combination therapy is considered an effective and safe treatment option for patients with IBS. However, further studies are needed to investigate the mechanisms of therapy and long-term outcomes.

A high fat, high sugar diet exacerbates persistent post-surgical pain and modifies the brain-microbiota-gut axis in adolescent rats

Persistent post-surgical pain (PPSP) occurs in a proportion of patients following surgical interventions. Research suggests that specific microbiome components are important for brain development and function, with recent studies demonstrating that chronic pain results in changes to the microbiome. Consumption of a high fat, high sugar (HFHS) diet can drastically alter composition of the microbiome and is a modifiable risk factor for many neuroinflammatory conditions. Therefore, we investigated how daily consumption of a HFHS diet modified the development of PPSP, brain structure and function, and the microbiome. In addition, we identified significant correlations between the microbiome and brain in animals with PPSP. Male and female rats were maintained on a control or HFHS diet. Animals were further allocated to a sham or surgery on postnatal day (p) p35. The von Frey task measured mechanical nociceptive sensitivity at a chronic timepoint (p65-67). Between p68-72 rats underwent in-vivo MRI to examine brain volume and diffusivity. At p73 fecal samples were used for downstream 16 s rRNA sequencing. Spearman correlation analyses were performed between individual microbial abundance and MRI diffusivity to determine if specific bacterial species were associated with PPSP-induced brain changes. We found that consumption of a HFHS diet exacerbated PPSP in adolescents. The HFHS diet reduced overall brain volume and increased white and grey matter density. The HFHS diet interacted with the surgical intervention to modify diffusivity in numerous brain regions which were associated with specific changes to the microbiome. These findings demonstrate that premorbid characteristics can influence the development of PPSP and advance our understanding of the contribution that the microbiome has on function of the brain-microbiota-gut axis.

The Role of the Gut Microbiota in Health, Diet, and Disease with a Focus on Obesity

The gut microbiota has been increasingly recognised as a critical determinant of human health, influencing a wide range of physiological processes. A healthy gut microbiota is essential for maintaining metabolic, immune, and gastrointestinal homeostasis, contributing to overall well-being. Alterations in its composition and functionality, often referred to as microbial dysbiosis, are strongly associated with the development of gut-related and systemic diseases. The gut microbiota synthesises several components and interacts with epithelial cell receptors, influencing processes that extend beyond nutritional status to the pathogenesis of diseases such as obesity, which extend beyond their known contribution to nutritional status. Therefore, this state-of-the-art review synthesises findings from recent studies on the composition, functions, and influencing factors of the gut microbiota, with a focus on its role in obesity. A systematic search of peer-reviewed literature was conducted to ensure comprehensive coverage, while expert insights are incorporated to discuss emerging research directions and future perspectives in the field.

Nitric oxide in the mechanisms of inhibitory effects of sodium butyrate on colon contractions in a mouse model of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a multifactorial disorder, with altered intestinal motility, visceral hypersensitivity, and dysfunction of the gut-brain axis. The aim of our study was to analyze the role of nitric oxide (NO) in the inhibitory effects of sodium butyrate on spontaneous contractility of proximal colon in a mouse model of IBS. IBS was induced by intracolonic infusion of acetic acid in the early postnatal period. Spontaneous contractions of proximal colon segments were studied in isometric conditions. The amplitude and frequency of colon contractions were higher in the IBS group. Sodium butyrate exerted inhibitory effects on colon contractions, which were less pronounced in IBS group. NO donors decreased spontaneous colon contractility and prevented the inhibitory effects of sodium butyrate in control and IBS groups. Nitric oxide synthase (NOS) inhibition by L-NAME increased contractile activity more effective in the control group and decreased the inhibitory action of sodium butyrate. In IBS group, preliminary application of L-NAME did not prevent sodium butyrate action. Our data indicate that butyrate exerts its inhibitory effects on colon motility at least partially through activation of NO synthesis. In the IBS model group, the NO-dependent mechanisms were less effective probably due to downregulation of NOS.

An evidence-based update on the diagnosis and management of irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction affecting 5% of the population. The cardinal symptoms are abdominal pain and altered stool form or frequency.

AREAS COVERED

Diagnosis and management of IBS. We searched the literature for diagnostic accuracy studies, randomized controlled trials, and meta-analyses. A positive diagnosis of IBS, alongside testing to exclude celiac disease, is recommended. Exhaustive investigation has a low yield. Patients should be offered traditional dietary advice. If response is incomplete, specialist dietetic guidance should be considered. Probiotics may be beneficial, but quality of evidence is poor. First-line treatment of constipation is with laxatives, with secretagogues used where these are ineffective. Anti-diarrheal drugs should be used first-line for diarrhea, with second-line drugs including 5-hydroxytryptamine-3 antagonists, eluxadoline, or rifaximin, where available. First-line treatment of abdominal pain should be with antispasmodics, with gut-brain neuromodulators prescribed second-line. Low-dose tricyclic antidepressants, such as amitriptyline, are preferred. Brain-gut behavioral therapies are effective and have evidence for efficacy in patients refractory to standard therapies.

EXPERT OPINION

Despite substantial advances, there remains scope for improvement in terms of both the diagnosis and management of IBS. Reinforcement of positive diagnostic strategies for the condition and novel treatment paradigms are required.

Exploring Gut Microbiota Imbalance in Irritable Bowel Syndrome: Potential Therapeutic Effects of Probiotics and Their Metabolites

Irritable bowel syndrome is a common functional gastrointestinal disorder characterized by recurrent abdominal discomfort, bloating, cramping, flatulence, and changes in bowel movements. The pathophysiology of IBS involves a complex interaction between motor, sensory, microbiological, immunological, and psychological factors. Diversity, stability, and metabolic activity of the gut microbiota are frequently altered in IBS, thus leading to a situation of gut dysbiosis. Therefore, the use of probiotics and probiotic-derived metabolites may be helpful in balancing the gut microbiota and alleviating irritable bowel syndrome symptoms. This review aimed to report and consolidate recent progress in understanding the role of gut dysbiosis in the pathophysiology of IBS, as well as the current studies that have focused on the use of probiotics and their metabolites, providing a foundation for their potential beneficial effects as a complementary and alternative therapeutic strategy for this condition due to the current absence of effective and safe treatments.

Meta-analysis of gut microbiota alterations in patients with irritable bowel syndrome

Introduction

Irritable bowel syndrome (IBS) is a common chronic disorder of gastrointestinal function with a high prevalence worldwide. Due to its complex pathogenesis and heterogeneity, there is urrently no consensus in IBS research.

Methods

We collected and uniformly reanalyzed 1167 fecal 16S rRNA gene sequencing samples (623 from IBS patients and 544 from healthy subjects) from 9 studies. Using both a random effects (RE) model and a fixed effects (FE) model, we calculated the odds ratios for metrics including bacterial alpha diversity, beta diversity, common genera and pathways between the IBS and control groups.

Results

Significantly lower alpha-diversity indexes were observed in IBS patients by random effects model. Twenty-six bacterial genera and twelve predicted pathways were identified with significant odds ratios and classification potentials for IBS patients. Based on these feature, we used transfer learning to enhance the predictive capabilities of our model, which improved model performance by approximately 10%. Moreover, through correlation network analysis, we found that Ruminococcaceae and Christensenellaceae were negatively correlated with vitamin B6 metabolism, which was decreased in the patients with IBS. Ruminococcaceae was also negatively correlated with tyrosine metabolism, which was decreased in the patients with IBS.

Discussion

This study revealed the dysbiosis of fecal bacterial diversity, composition, and predicted pathways of patients with IBS by meta-analysis and identified universal biomarkers for IBS prediction and therapeutic targets.

The Role of Gut Microbiome in Irritable Bowel Syndrome: Implications for Clinical Therapeutics

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder (FGID) characterized by chronic or recurrent gastrointestinal symptoms without organic changes, and it is also a common disorder of gut-brain interaction (DGBIs).. The symptoms of IBS not only affect the quality of life for individual patients but also place a significant burden on global healthcare systems. The lack of established and universally applicable biomarkers for IBS, along with the substantial variability in symptoms and progression, presents challenges in developing effective clinical treatments. In recent years, preclinical and clinical studies have linked the pathogenesis of IBS to alterations in the composition and function of the intestinal microbiota. Within the complex microbial community of the gut, intricate metabolic and spatial interactions occur among its members and between microbes and their hosts. Amid the multifaceted pathophysiology of IBS, the role of intestinal microenvironment factors in symptom development has become more apparent. This review aims to delve into the changes in the composition and structure of the gut microbiome in individuals with IBS. It explores how diet-mediated alterations in intestinal microbes and their byproducts play a role in regulating the pathogenesis of IBS by influencing the "brain-gut" axis, intestinal barrier function, immune responses, and more. By doing so, this review seeks to lay a theoretical foundation for advancing the development of clinical therapeutics for IBS.

Microbiota modulation in disorders of gut-brain interaction

Disorders of gut-brain interaction (DGBI) are common chronic conditions characterized by persistent and recurring gastrointestinal symptoms triggered by several pathophysiological factors, including an altered gut microbiota. The most common DGBI are irritable bowel syndrome (IBS), functional constipation (FC) and functional dyspepsia (FD). Recently, a deep understanding of the role of the gut microbiota in these diseases was possible due to multi-omics methods capable to provide a comprehensive assessment. Most of the therapies recommended for these patients, can modulate the gut microbiota such as diet, prebiotics, probiotics and non-absorbable antibiotics, which were shown to be safe and effective. Since patients complain symptoms after food ingestion, diet represents the first line therapeutic approach. Avoiding dietary fat and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, and increasing the number of soluble fibers represent the therapeutic choices for FD, IBS and FC respectively. Probiotics, as a category, have been employed with good results in all the abovementioned DGBI. Rifaximin has been shown to be useful in the context of bowel related disorders, although a recent trial showed positive results for FD. Fecal microbiota transplantation has been tested for IBS and FC with promising results. In this review, we will briefly summarize the current understanding on dysbiosis and discuss microbiota modulation strategies to treat patients with DGBI.

Effect of Chemotherapy on Fusobacterium nucleatum Abundance in Colorectal Cancer Patients: A Study on Relapsing Patients

An intricate relationship exists, and interactions occur between the gut microbiota and colorectal cancer (CRC). Recent studies have indicated that inflammatory reactions stimulated by Fusobacterium nucleatum (Fn) lead to the development of CRC. Radical surgery combined with adjuvant chemotherapy is the primary treatment approach for most CRC patients. This study was designed to evaluate the abundance of Fn as part of the gut microbiota in patients with CRC compared to healthy individuals and to assess the effect of the gut microbiota Fn on patients undergoing adjuvant chemotherapy and those experiencing CRC relapse. There were 201 participants, comprising 50 healthy controls and 151 CRC patients. Stool samples were collected from three CRC groups (postoperatively, chemotherapy and relapse), and the fourth was the healthy control group. The amount of Fn in each sample was analyzed using quantitative loop-mediated isothermal amplification-phenol red (QLAMP-PhR), a novel biomolecular method that targets regions encoding the specific Fn FadA gene. Compared with healthy control stool samples, the Fn levels were significantly elevated in all CRC patient groups (P < 0.001), and it was significantly more frequent in the CRC relapse patients (group C) (P < 0.001). In addition, Fn abundance increased significantly in the distal colon compared to the proximal colon (P < 0.001). Both CRC relapse and chemotherapy exert significant reciprocal effects on the gut microbiota Fn of CRC patients. Microbiota-based intervention may be beneficial for patients during postoperative care, especially in CRC relapsing cases. Registration: This study of the clinical trial has been registered in the ISRCTN registry with study registration number ISRCTN53358464. https://www.isrctn.com/ISRCTN53358464.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01279-6.

Unsupervised machine learning highlights the challenges of subtyping disorders of gut-brain interaction

BACKGROUND

Unsupervised machine learning describes a collection of powerful techniques that seek to identify hidden patterns in unlabeled data. These techniques can be broadly categorized into dimension reduction, which transforms and combines the original set of measurements to simplify data, and cluster analysis, which seeks to group subjects based on some measure of similarity. Unsupervised machine learning can be used to explore alternative subtyping of disorders of gut-brain interaction (DGBI) compared to the existing gastrointestinal symptom-based definitions of Rome IV.

PURPOSE

This present review aims to familiarize the reader with fundamental concepts of unsupervised machine learning using accessible definitions and provide a critical summary of their application to the evaluation of DGBI subtyping. By considering the overlap between Rome IV clinical definitions and identified clusters, along with clinical and physiological insights, this paper speculates on the possible implications for DGBI. Also considered are algorithmic developments in the unsupervised machine learning community that may help leverage increasingly available omics data to explore biologically informed definitions. Unsupervised machine learning challenges the modern subtyping of DGBI and, with the necessary clinical validation, has the potential to enhance future iterations of the Rome criteria to identify more homogeneous, diagnosable, and treatable patient populations.

Gut Microbiome Alterations Following Oral Serum-Derived Bovine Immunoglobulin Administration in the Management of Dysbiosis

INTRODUCTION

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are chronic disorders of the gastrointestinal tract associated with gut microbiota dysbiosis and inflammation. Serum-derived bovine immunoglobulin (SBI) is used to manage IBS and IBD and has shown prebiotic-like effects in ex vivo models. Re-establishing a healthy gut microbiome with novel treatments like SBI could help treat the underlying causes of these diseases leading to higher and sustained patient response. The objective of this study was to assess whether supplementation with SBI would improve dysbiosis in IBD and IBS patients.

METHODS

This cross-sectional, single-site study had each participant serving as their own control. Stool samples from 18 patients with either IBS or IBD were analyzed before and after SBI administration. The relative abundance of bacterial diversity was assessed using metagenomic next-generation sequencing-based profiling.

RESULTS

Species diversity statistically significantly increased for measures of richness (Shannon index) (p < 0.0082) and evenness (Gini-Simpson index) (p < 0.0017). Phylum-level changes showed a 2.7-fold increase in Actinobacteria (p = 0.0181), 0.66-fold decrease in Bacteroidetes (p = 0.0401), and 0.38-fold decrease in Proteobacteria (p = 0.0071) after treatment with SBI. At the genus level, the relative abundances showed decreased Alistipes (p = 0.0121) and decreased Bacteroides (p = 0.0108) as well as increased Bifidobacterium (p = 0.0204), compared to pre-treatment levels. At the genus level, a 1.8-fold increase of Bifidobacterium breve (p = 0.0225) occurred upon treatment with SBI.

CONCLUSION

These findings confirm the prebiotic effects of SBI and suggest an additional mechanism of action in managing IBD and IBS symptoms. SBI re-establishes homeostasis in patients with IBD and IBS by decreasing Proteobacteria and increasing Bifidobacteria and species diversity. These insights highlight the promise of new therapeutic strategies for managing IBS and IBD by targeting dysbiosis and underscore the potential of personalized treatments based on a patient's gut microbiome profile.

Chronic constipation and gut microbiota: current research insights and therapeutic implications

Chronic constipation is a prevalent clinical condition. Its etiology and pathogenesis have not yet been fully understood. In recent years, mounting evidence suggests a close association between chronic constipation and intestinal dysbiosis, including alterations in the colony structure and metabolites, as well as the modulation of bowel movements via the brain-gut-microbiota axis. With the deepening of related research, probiotic-related therapies are expected to become a potential first-line treatment for chronic constipation in the future. In this review, we summarize the current research insights into the intricate relationships between chronic constipation and the gut microbiota and briefly discuss several different approaches for treating chronic constipation. The findings from this review may advance our understanding of the pathological mechanisms underlying chronic constipation and, ultimately, translate them into improvements in patient care.

Microbiome Shifts and Their Impact on Gut Physiology in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is one of the most prevalent functional gastrointestinal disorders characterized by recurrent abdominal pain and altered bowel habits. The exact pathophysiological mechanisms for IBS development are not completely understood. Several factors, including genetic predisposition, environmental and psychological influences, low-grade inflammation, alterations in gastrointestinal motility, and dietary habits, have been implicated in the pathophysiology of the disorder. Additionally, emerging evidence highlights the role of gut microbiota in the pathophysiology of IBS. This review aims to thoroughly investigate how alterations in the gut microbiota impact physiological functions such as the brain-gut axis, immune system activation, mucosal inflammation, gut permeability, and intestinal motility. Our research focuses on the dynamic "microbiome shifts", emphasizing the enrichment or depletion of specific bacterial taxa in IBS and their profound impact on disease progression and pathology. The data indicated that specific bacterial populations are implicated in IBS, including reductions in beneficial species such as Lactobacillus and Bifidobacterium, along with increases in potentially harmful bacteria like Firmicutes and Proteobacteria. Emphasis is placed on the imperative need for further research to delineate the role of specific microbiome alterations and their potential as therapeutic targets, providing new insights into personalized treatments for IBS.

Results from a Cross-Sectional Observational Study Examining Irritable Bowel Syndrome Patients Six Months After Finishing Their Participation in the ViIBS Trial

BACKGROUND/OBJECTIVES

A recent clinical (ViIBS) trial investigating the effects of a balanced multi-strain synbiotic in irritable bowel syndrome (IBS) patients showed that twelve weeks of treatment resulted in significant improvements across all major IBS symptoms. The current observational study pursued three aims: investigate patients' attitude towards the intake of pro- or synbiotics during the six months after finishing their trial participation, determine the severity of IBS symptoms, and assess IBS diagnosis scores.

METHODS

During a single six-month follow-up examination, patients were asked about the intake of probiotics or synbiotics. For the study, former placebo-group patients who abstained from taking probiotics were compared with synbiotic-group patients who continued taking the tested synbiotic. IBS symptom severity was assessed with the IBS-Severity of Symptoms Scale and the IBS diagnosis score with the IBS questionnaire of the World Gastroenterology Organisation.

RESULTS

The control group comprised 17 patients (out of 70 from the placebo group participating in the follow-up) and the treatment group 75 (out of 91 examined). IBS symptom severity was significantly lower in the treatment group (23.5 ± 33.1) than in the placebo group (232.6 ± 35.1). IBS diagnosis scores were 5.9 ± 2.5 and 21.2 ± 2.0 in the treatment and control group, respectively.

CONCLUSIONS

Measurement values for the treatment group indicate the absence of IBS. The results indicate that the prolonged administration of the balanced multi-strain synbiotic can potentially reduce IBS symptom severity and IBS diagnosis scores to levels indicating the absence of IBS, an observation to be followed up in a controlled clinical trial.

Impact of low FODMAP sourdough bread on gut microbiota using an in vitro colonic fermentation model

This study explores the development of whole-grain sourdough bread with reduced FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) content to offer dietary solutions for individuals with irritable bowel syndrome (IBS). Three sourdough breads were prepared using different lactic acid bacteria (LAB) strains including Lactiplantibacillus plantarum FST1.7 (SD-FST1.7), Lacticaseibacillus paracasei R3 (SD-R3), and Pediococcus pentosaceus RYE106 (SD-RYE106). A control sourdough bread was prepared using baker's yeast (SD-control). In vitro digestion and in vitro colonic fermentation were employed on bread samples with cellulose (negative control) and inulin (positive control), followed by 16S rRNA sequencing and short-chain fatty acid (SCFA) analysis to evaluate the impact on gut microbiota and SCFA levels. Alpha and beta diversity did not reveal any significant differences within the groups following in vitro colonic fermentation (FDR > 0.05). Taxonomic analysis displayed Firmicutes as the predominant phylum across all fecal samples at the end of colonic fermentation. Actinobacteriota was significantly lower in cellulose fermented fecal samples compared to samples fermented with SD-Control (ANCOMBC, FDR = 0.02) and inulin (ANCOMBC, FDR = 0.0001). Fecal samples fermented with inulin had significantly higher Bacteroidota levels compared to those fermented with cellulose (ANCOMBC, FDR =0.002). Acetate levels were higher in fecal samples fermented with SD-FST1.7 compared to those fermented with SD-R3 and SD-RYE106 (p = 0.03 for both). Positive correlations between butyrate and Lachnospira, Agathobacter, and Bifidobacterium were observed, demonstrating the potential of sourdough fermentation to influence gut health and support IBS management.

Cross-Cohort Gut Microbiome Signatures of Irritable Bowel Syndrome Presentation and Treatment

Irritable bowel syndrome (IBS) is a prevalent disorder of gut-brain interaction without a reliable cure. Evidence suggests that an alteration of the gut microbiome may contribute to IBS pathogenesis, motivating the development of microbiome-targeted therapies to alleviate IBS symptoms. However, IBS-specific microbiome signatures are variable across cohorts. A total of 9204 datasets were meta-analyzed, derived from fourteen IBS microbiome discovery cohorts, three validation cohorts for diet-microbiome interactions, and five rifaximin therapy cohorts. The consistent bacterial species and functional signatures associated with IBS were identified. Network analysis revealed two distinct IBS-enriched microbiota clusters; obligate anaerobes that are found commonly in the gut, and facultative anaerobes typically present in the mouth, implying a possible association between oral bacterial translocation to gut and IBS pathogenesis. By analyzing diet-microbiome interactions, microbiota-targeted diets that can potentially modulate the altered gut microbiota of IBS subjects toward a healthy status were identified. Furthermore, rifaximin treatment of IBS subjects was linked with a reduction in the abundance of facultatively anaerobic pathobionts. Gut microbiome signatures were identified across IBS cohorts that may inform the development of therapies for microbiome modulation in IBS. The microbiota-targeted diet patterns described may enable nutritional intervention trials in IBS and for assisting dietary management.

Gut microbiota and irritable bowel syndrome: status and prospect

Irritable bowel syndrome (IBS) is a very common gastrointestinal disease that, although not as aggressive as tumors, affects patients' quality of life in different ways. The cause of IBS is still unclear, but more and more studies have shown that the characteristics of the gut microbiota, such as diversity, abundance, and composition, are altered in patients with IBS, compared to the healthy population, which confirms that the gut microbiota plays a crucial role in the development of IBS. This paper aims to identify the commonalities by reviewing a large body of literature. Changes in the characteristics of gut microbiota in patients with different types of IBS are discussed, relevant mechanisms are described, and the treatment modalities of gut microbiota in IBS are summarized. Although there are more clinical trials that have made good progress, more standardized, more generalized, larger-scale, multi-omics clinical studies are what is missing. Overall, gut microbiota plays a crucial role in the development of IBS, and there is even more potential for treating IBS by modulating gut microbiota.

Mechanisms of Electroacupuncture in Alleviating Visceral Hypersensitivity in Post-Infectious Irritable Bowel Syndrome Mice: The Role of GDNF Signaling Pathway and Gut Microbiota

INTRODUCTION

Post-infectious irritable bowel syndrome (PI-IBS) is a functional bowel disease that develops following an acute gastrointestinal infection. Electroacupuncture (EA) can regulate the gut microbiota and alleviate visceral hypersensitivity. Glial cell-derived neurotrophic factor (GDNF) is a potential factor in visceral hypersensitivity reactions. The aim of this study was to explore whether EA could alleviate visceral hypersensitivity in PI-IBS by regulating gut microbiota through GDNF signaling.

METHODS

2,4,6-trinitrobenzene sulfonic acid was used to induce visceral hypersensitivity in PI-IBS mice. Intestinal visceral sensitivity was assessed by using the abdominal withdrawal reflex (colorectal distention). 16S ribosomal RNA sequencing profiles the gut microbiome community.

RESULTS

GDNF can exacerbate the imbalances of the gut microbiota and increase visceral hypersensitivity compared with the model group. Whereas EA treatment increases the richness and diversity of the gut microbiota, decreases differences among species and alleviates visceral sensitivity.

CONCLUSION

EA can alleviate visceral hypersensitivity in PI-IBS by regulating the gut microbiota via GDNF signaling, providing new insights for mechanistic research on EA in PI-IBS treatment.

Impact of Enteric Nervous Cells on Irritable Bowel Syndrome: Potential Treatment Options

Irritable bowel syndrome (IBS) is a condition that significantly impacts the lifestyle, health, and habits of numerous individuals worldwide. Its diagnosis and classification are based on the Rome criteria, updated periodically to reflect new research findings in this field. IBS can be classified into different types based on symptoms, each with distinct treatment approaches and some differences in their pathophysiology. The exact pathological background of IBS remains unclear, with many aspects still unknown. Recent research developments suggest that disorders in the brain-gut-microbiota axis are key contributors to the symptoms and severity of IBS. The central nervous system (CNS) interacts bidirectionally with intestinal processes within the lumen and the intestinal wall, with the autonomic nervous system, particularly the vagus nerve, playing an important role. However, the enteric nervous system (ENS) is also crucial in the pathophysiological pathway of IBS. The apeline-corticotropin-releasing factor (CRF)-toll-like receptor 4 (TLR4) signaling route via enteric glia and serotonin production in enteroendocrine cells at the enteric barrier are among the most well-understood new findings that affect IBS through the ENS. Additionally, the microbiota regulates neuronal signals, modifying enteric function by altering the number of enteric bacteria and other mechanisms. Given the limited therapeutic options currently available, it is essential to identify new treatment targets, with the brain-gut axis, particularly the enteric nervous system, being a promising focus. This study aims to delineate the molecular mechanisms that induce IBS and to suggest potential targets for future research and treatment of this potentially debilitating disease.

[Psychocorporal approach to functional somatic disorders]

Functional somatic disorders (FSD) are common conditions that result in a significant deterioration of the quality of life. Their origin is multifactorial and poorly understood, and their management is often inadequately defined. Medications typically show limited effectiveness, while mind-body approaches play a central role, guided by three key principles: establishing an empathetic, respectful, and sincere doctor-patient relationship; promoting regular and gradual physical activity; and implementing cognitive behavioral therapy (CBT). Special attention must be devoted to establishing a trustworthy relationship between the physician and the patient. Recognizing the reality and severity of symptoms and providing a positive diagnosis as well as an explanatory model to account for them rationally are fundamental aspects of patient management. Cognitive and behavioral maintenance factors should be investigated and constitute therapeutic targets. Cognitive factors include focused attention on body functioning and catastrophizing. Patients frequently display avoidance behaviors, particularly in relation to physical exertion, and it is crucial to motivate them to reintroduce gradual physical activity customized to their abilities. This approach has demonstrated efficacy in improving fatigue, pain, and the physical and mental quality of life for patients with FSD. Among psychotherapeutic approaches, the benefit of CBT is well-established. The combination of gradual physical activity and CBT appears to be complementary. Other mind-body approaches such as mindfulness meditation might help although their level of evidence is weaker. Given the prevalence of FSD in the general population, it seems necessary for all physicians to be trained in managing this condition.

Rifaximin and alternative agents in the management of irritable bowel syndrome: A comprehensive review

Rifaximin, a broad-spectrum antibiotic, boasts a unique chemical composition and pharmacokinetic profile, rendering it highly effective in treating irritable bowel syndrome (IBS). Its minimal systemic absorption confines its impact to the gastrointestinal (GI) tract, where it yields significant therapeutic benefits. This review examines rifaximin's physico-chemical attributes and its role in managing IBS symptoms. Its molecular structure facilitates intestinal lumen retention postoral administration, minimizing systemic exposure and adverse effects. This targeted action is crucial in addressing the gut microbiota's role in IBS pathophysiology. By modifying microbial populations and their metabolite production, rifaximin mitigates symptoms like bloating, irregular bowel habits, and abdominal pain associated with IBS. It achieves this by reducing pathogenic bacteria and altering bacterial metabolism, enhancing mucosal and immune function. Clinical trials affirm rifaximin's superiority over placebo and conventional therapies in alleviating overall IBS symptoms and addressing small intestine bacterial overgrowth (SIBO). Despite its promising efficacy and sustained symptom relief, further research is essential to optimize long-term effectiveness and dosing regimens. Rifaximin stands as a vital treatment option for IBS due to its distinctive properties and clinical utility; yet, ongoing investigation is imperative for maximizing its therapeutic benefits.

Effect of Personalized Prebiotic and Probiotic Supplements on the Symptoms of Irritable Bowel Syndrome: An Open-Label, Single-Arm, Multicenter Clinical Trial

BACKGROUND/OBJECTIVES

Prebiotics and probiotics have been reported to improve symptoms of irritable bowel syndrome (IBS). Nevertheless, the effects of prebiotics/probiotics can vary depending on the IBS subtypes. The purpose of this study was to investigate the effects of personalized prebiotic and probiotic supplements based on intestinal microbiota and IBS subtypes in patients.

METHODS

Patients with diarrhea-type IBS (IBS-D), constipation-type IBS (IBS-C), and mixed-type IBS (IBS-M) were enrolled (n = 40 per group; total: n = 120). Personalized prebiotic and probiotic supplements were determined according to the IBS subtypes and intestinal microbiota. The patients received supplements for 4 weeks. The primary outcome was the change in the IBS-severity scoring system from baseline to week 4.

RESULTS

The IBS-severity scoring system significantly decreased in all patients (-38.0 [95% confidence interval (CI): -53.6, -22.4]; p < 0.001), in patients with IBS-D (-44.5 [95% CI: -70.6, -18.5]; p = 0.004) and IBS-C (-51.2 [95% CI: -79.4, -22.9]; p = 0.002), but not in those with IBS-M (-20.0 [95% CI: -48.0, 8.1]; p = 0.47). In this study, no serious adverse events were observed that had a causal relationship with the intervention.

CONCLUSIONS

In conclusion, personalized prebiotic and probiotic supplements selected according to individual intestinal microbiota and IBS subtype may alleviate the severity of IBS symptoms, particularly in patients with IBS-C and IBS-D.

Probiotics plus vitamin D in irritable bowel syndrome: a prospective multicentric non-interventional study

BACKGROUND

Patients with irritable bowel syndrome (IBS) experience recurrent symptoms and anxiety disorders that significantly impact their quality of life (QoL). The aim of the study was to assess in daily practice the benefit of the combination of three probiotic strains (Lactobacillus plantarum CETC 7484 and CETC 7485; Pediococcus acidilactici CECT 7483) plus vitamin D in patients with diarrhea-predominant IBS (IBS-D) or IBS with mixed bowel movements (IBS-M).

METHODS

This was a prospective, multicenter, non-interventional study in adult patients with IBS-D or IBS-M (Rome IV criteria) followed by private-practice gastroenterologists. Patients received daily one sachet of a combination of probiotics (3×109 CFU) and vitamin D (10 μg) for 42 days. The primary endpoint was the responder rate at D42 (≥50% and/or ≥100-point decrease of IBS-Severity Scoring System; IBS-SSS). Gut-related anxiety was measured with the Visceral Sensitivity Index (VSI).

RESULTS

The full analysis set population included 246 patients (mean age, 51.2±15.4 years; women, 73.2%; IBS-D, 56.1%; IBS-M, 43.9%). At D42, among the 89 patients with evaluable data, the responder rate was 62.9% with a mean decrease of IBS-SSS of 146.6±125.9 (P<0.0001). Changes of IBS-SSS were significantly correlated with changes of IBS-QoL (r=-0.78; P<0.0001), HAD-anxiety (r=0.46; P<0.0001), HAD-depression (r=0.61; P<0.001) and VSI (r=0.74; P<0.0001).

CONCLUSIONS

These real-life results are in line with a previous randomized clinical trial demonstrating the benefits of this combination in IBS-D and IBS-M. Symptom relief was associated with improvement of IBS-QoL, anxiety, depression and specifically gut-related anxiety.

A Multicenter Randomized Controlled Trial of Microbiome-Based Artificial Intelligence-Assisted Personalized Diet vs Low-Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols Diet: A Novel Approach for the Management of Irritable Bowel Syndrome

INTRODUCTION

Personalized management strategies are pivotal in addressing irritable bowel syndrome (IBS). This multicenter randomized controlled trial focuses on comparing the efficacy of a microbiome-based artificial intelligence-assisted personalized diet (PD) with a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (FODMAP) for IBS management.

METHODS

One hundred twenty-one patients participated, with 70 assigned to the PD group and 51 to the FODMAP diet group. IBS subtypes, demographics, symptom severity (IBS-SSS), anxiety, depression, and quality of life (IBS-QOL) were evaluated. Both interventions spanned 6 weeks. The trial's primary outcome was the within-individual difference in IBS-SSS compared between intervention groups.

RESULTS

For the primary outcome, there was a change in IBS-SSS of -112.7 for those in the PD group vs -99.9 for those in the FODMAP diet group ( P = 0.29). Significant improvement occurred in IBS-SSS scores ( P < 0.001), frequency ( P < 0.001), abdominal distension ( P < 0.001), and life interference ( P < 0.001) in both groups. In addition, there were significant improvements in anxiety levels and IBS-QOL scores for both groups ( P < 0.001). Importantly, PD was effective in reducing IBS SSS scores across all IBS subtypes IBS-Constipation (IBS-C; P < 0.001), IBS-Diarrhea (IBS-D; P = 0.01), and IBS-Mixed (IBS-M; P < 0.001) while FODMAP diet exhibited comparable improvements in IBS-C ( P = 0.004) and IBS-M ( P < 0.001). PD intervention significantly improved IBS-QOL scores for all subtypes (IBS-C [ P < 0.001], IBS-D [ P < 0.001], and IBS-M [ P = 0.008]) while the FODMAP diet did so for the IBS-C ( P = 0.004) and IBS-D ( P = 0.022). Notably, PD intervention led to significant microbiome diversity shifts ( P < 0.05) and taxa alterations compared with FODMAP diet.

DISCUSSION

The artificial intelligence-assisted PD emerges as a promising approach for comprehensive IBS management. With its ability to address individual variation, the PD approach demonstrates significant symptom relief, enhanced QOL, and notable diversity shifts in the gut microbiome, making it a valuable strategy in the evolving landscape of IBS care.

Fecal microbiota transplantation influences microbiota without connection to symptom relief in irritable bowel syndrome patients

Imbalanced microbiota may contribute to the pathophysiology of irritable bowel syndrome (IBS), thus fecal microbiota transplantation (FMT) has been suggested as a potential treatment. Previous studies on the relationship between clinical improvement and microbiota after FMT have been inconclusive. In this study, we used 16S rRNA gene amplicon and shotgun metagenomics data from a randomized, placebo controlled FMT trial on 49 IBS patients to analyze changes after FMT in microbiota composition and its functional potential, and to identify connections between microbiota and patients' clinical outcome. As a result, we found that the successful modulation of microbiota composition and functional profiles by FMT from a healthy donor was not associated with the resolution of symptoms in IBS patients. Notably, a donor derived strain of Prevotella copri dominated the microbiota in those patients in the FMT group who had a low relative abundance of P. copri pre-FMT. The results highlight the multifactorial nature of IBS and the role of recipient's microbiota in the colonization of donor's strains.

Lactiplantibacillus plantarum Regulates Intestinal Physiology and Enteric Neurons in IBS through Microbial Tryptophan Metabolites

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder characterized by visceral pain and gut dysmotility. However, the specific mechanisms by which Lactobacillus strains relieve IBS remain unclear. Here, we screened Lactobacillus strains from traditional Chinese fermented foods with potential IBS-alleviating properties through in vitro and in vivo experiments. We demonstrated that Lactiplantibacillus plantarum D266 (Lp D266) administration effectively modulates intestinal peristalsis, enteric neurons, visceral hypersensitivity, colonic inflammation, gut barrier function, and mast cell activation. Additionally, Lp D266 shapes gut microbiota and enhances tryptophan (Trp) metabolism, thus activating the aryl hydrocarbon receptor (AhR) and subsequently enhancing IL-22 production to maintain gut homeostasis. Mechanistically, Lp D266 potentially modulates colonic physiology and enteric neurons by microbial tryptophan metabolites. Further, our study indicates that combining Lp D266 with Trp synergistically ameliorates IBS symptoms. Together, our experiments identify the therapeutic efficacy of tryptophan-catabolizing Lp D266 in regulating gut physiology and enteric neurons, providing new insights into the development of probiotic-mediated nutritional intervention for IBS management.

Microbiota-Short Chain Fatty Acid Relationships Underlie Clinical Heterogeneity and Identify Key Microbial Targets in Irritable Bowel Syndrome (IBS)

Background

Identifying microbial targets in irritable bowel syndrome (IBS) and other disorders of gut-brain interaction (DGBI) is challenging due to the dynamic nature of microbiota-metabolite-host interactions. SCFA are key microbial metabolites that modulate intestinal homeostasis and may influence IBS pathophysiology. We aimed to assess microbial features associated with short chain fatty acids (SCFA) and determine if features varied across IBS subtypes and endophenotypes. Among 96 participants who were screened, 71 completed the study. We conducted in-depth investigations of stool microbial metagenomes, stool SCFA, and measurable IBS traits (stool bile acids, colonic transit, stool form) in 41 patients with IBS (IBS with constipation [IBS-C] IBS with diarrhea [IBS-D]) and 17 healthy controls. We used partial canonical correspondence analyses (pCCA), conditioned on transit, to quantify microbe-SCFA associations across clinical groups. To explore relationships between microbially-derived SCFA and IBS traits, we compared gut microbiome-encoded potential for substrate utilization across groups and within a subset of participants selected by their stool characteristics as well as stool microbiomes of patients with and without clinical bile acid malabsorption.

Results

Overall stool microbiome composition and individual taxa abundances differed between clinical groups. Microbes-SCFA associations differed across groups and revealed key taxa including Dorea sp. CAG:317 and Bifidobacterium pseudocatenulatum in IBS-D and Akkermansia muciniphila and Prevotella copri in IBS-C that that may drive subtype-specific microbially-mediated mechanisms. Strongest microbe-SCFA associations were observed in IBS-D and several SCFA-producing species surprisingly demonstrated inverse correlations with SCFA. Fewer bacterial taxa were associated with acetate to butyrate ratios in IBS compared to health. In participants selected by stool form, we demonstrated differential abundances of microbial genes/pathways for SCFA metabolism and degradation of carbohydrates and mucin across groups. SCFA-producing taxa were reduced in IBS-D patients with BAM.

Conclusion

Keystone taxa responsible for SCFA production differ according to IBS subtype and traits and the IBS microbiome is characterized by reduced functional redundancy. Differences in microbial substrate preferences are also linked to bowel functions. Focusing on taxa that drive SCFA profiles and stool form may be a rational strategy for identifying relevant microbial targets in IBS and other DGBI.

Effective process quality control management for constipation prevention in hospitalized patients with acute coronary syndrome: An observational study

Objective

To evaluate the effectiveness of monitoring and managing process quality control indicators in the prevention of constipation among hospitalized patients with acute coronary syndrome (ACS).

Methods

A total of 512 hospitalized patients diagnosed with ACS between January and June 2022 were screened for inclusion in the study. Ultimately, 456 eligible participants were enrolled and divided into two groups based on the chronological order of admission: the control group and the observation group. Upon admission, both groups of patients received routine constipation prevention measures in the department. However, the observation group was subjected to targeted process quality control management, which included monitoring and managing five indicators related to constipation prevention: correctness of bowel movement recording; usage rate of laxatives; execution rate of physical interventions; implementation rate of constipation prevention education; completion rate of dietary structure and habit assessments. Data were analyzed using SPSS, with t tests and χ 2 tests for group comparisons.

Results

In comparison to the control group, the observation group demonstrated significant advantages in terms of constipation incidence, completion rates of the five process quality control indicators, occurrence rates of adverse cardiac events during defecation, and PHQ-9 scores before discharge. These disparities demonstrated statistical significance with a p value < 0.05.

Conclusion

Target-oriented process quality control management is shown to be effective in reducing constipation incidence and adverse cardiac events during constipation episodes, as well as alleviating depressive symptoms among ACS patients, thus providing a safe and effective approach to constipation prevention.

Synbiotics as Treatment for Irritable Bowel Syndrome: A Review

Irritable bowel syndrome is a persistent disturbance of the function of the gastrointestinal tract with a prevalence of about 11.2% in the population at large. While the etiology of the disorder remains unclear, there is mounting evidence that the disturbance of the gut microbiota is at least one contributing factor. This insight resulted in clinical trials investigating the therapeutic effects of products containing probiotic microorganisms. Most studies with IBS patients have evaluated the therapeutic effects of mono- and multi-strain probiotics, but only a few studies have investigated the efficacy of synbiotics (combinations of probiotic bacteria and one or more prebiotic components). This review summarizes the results from eight randomized, placebo-controlled clinical trials that investigated the efficacy of synbiotic preparations (three mono-strain and five multi-strain products) in adult IBS patients. While data remain sparse, some of the surveyed clinical trials have demonstrated interesting efficacy results in IBS patients. To allow a judgment of the role played by synbiotics in the treatment of IBS patients, more high-quality clinical trials are needed.

Fecal Microbiota Characteristics in Constipation-Predominant and Mixed-Type Irritable Bowel Syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common condition that affects the lifestyle of patients. It is associated with significant changes in the composition of the gut microbiome, but the underlying microbial mechanisms remain to be fully understood. We study the fecal microbiome of patients with constipation-predominant IBS (IBS-C) and mixed-type IBS (IBS-M).

METHODS

We sequenced the V3 region of the 16S rRNA on the Ion Torrent PGM sequencing platform to study the microbiome.

RESULTS

In the patients with IBS-C and IBS-M, an increase in alpha diversity was found, compared to the healthy group, and differences in beta diversity were also noted. At the phylum level, both IBS subtypes showed an increase in the Firmicutes/Bacteroidetes ratio, as well as an increase in the abundance of Actinobacteria and Verrucomicrobiota. Changes in some types of bacteria were characteristic of only one of the IBS subtypes, while no statistically significant differences in the composition of the microbiome were detected between IBS-C and IBS-M.

CONCLUSIONS

This study was the first to demonstrate the association of Turicibacter sanguinis, Mitsuokella jalaludinii, Erysipelotrichaceae UCG-003, Senegalimassilia anaerobia, Corynebacterium jeikeium, Bacteroides faecichinchillae, Leuconostoc carnosum, and Parabacteroides merdae with IBS subtypes.

Acupuncture influences multiple diseases by regulating gut microbiota

Acupuncture, an important green and side effect-free therapy in traditional Chinese medicine, is widely use both domestically and internationally. Acupuncture can interact with the gut microbiota and influence various diseases, including metabolic diseases, gastrointestinal diseases, mental disorders, nervous system diseases, and other diseases. This review presents a thorough analysis of these interactions and their impacts and examines the alterations in the gut microbiota and the potential clinical outcomes following acupuncture intervention to establish a basis for the future utilization of acupuncture in clinical treatments.

A meta-analysis of randomized controlled trials evaluating the effectiveness of fecal microbiota transplantation for patients with irritable bowel syndrome

OBJECTIVE

Multiple randomized controlled trials (RCTs) have investigated the efficacy of fecal microbiota transplantation (FMT) for irritable bowel syndrome (IBS), but have yielded inconsistent results. We updated the short-term and long-term efficacy of FMT in treating IBS, and performed a first-of-its-kind exploration of the relationship between gut microbiota and emotions.

METHODS

We conducted a comprehensive search of PubMed, Embase, Web of Science, and the Cochrane Library using various search strategies to identify all eligible studies. The inclusion criteria for data extraction were randomized controlled trials (RCTs) that investigated the efficacy of fecal microbiota transplantation (FMT) compared to placebo in adult patients (≥ 18 years old) with irritable bowel syndrome (IBS). A meta-analysis was then performed to assess the summary relative risk (RR) and corresponding 95% confidence intervals (CIs).

RESULTS

Out of 3,065 potentially relevant records, a total of 10 randomized controlled trials (RCTs) involving 573 subjects met the eligibility criteria for inclusion in the meta-analysis. The meta-analyses revealed no significant differences in short-term (12 weeks) (RR 0.20, 95% CI -0.04 to 0.44), long-term (52 weeks) global improvement (RR 1.38, 95% CI 0.87 to 2.21), besides short-term (12 weeks) (SMD - 48.16, 95% CI -102.13 to 5.81, I2 = 90%) and long-term (24 weeks) (SMD 2.16, 95% CI -60.52 to 64.83, I2 = 68%) IBS-SSS. There was statistically significant difference in short-term improvement of IBS-QoL (SMD 10.11, 95% CI 0.71 to 19.51, I2 = 82%), although there was a high risk of bias. In terms of long-term improvement (24 weeks and 54 weeks), there were no significant differences between the FMT and placebo groups (SMD 7.56, 95% CI 1.60 to 13.52, I2 = 0%; SMD 6.62, 95% CI -0.85 to 14.08, I2 = 0%). Sensitivity analysis indicated that there were visible significant effects observed when the criteria were based on Rome IV criteria (RR 16.48, 95% CI 7.22 to 37.62) and Gastroscopy (RR 3.25, 95%CI 2.37 to 4.47), Colonoscopy (RR 1.42, 95% CI 0.98 to 2.05). when using mixed stool FMT based on data from two RCTs, no significant difference was observed (RR 0.94, 95% CI 0.66 to -1.34). The remission of depression exhibited no significant difference between the FMT and placebo groups at the 12-week mark (SMD - 0.26, 95% CI -3.09 to 2.58), and at 24 weeks (SMD - 2.26, 95% CI -12.96 to 8.45). Furthermore, major adverse events associated with FMT were transient and self-limiting.

DISCUSSION

Based on the available randomized controlled trials (RCTs), the current evidence does not support the efficacy of FMT in improving global IBS symptoms in the long term. The differential results observed in subgroup analyses raise questions about the accurate identification of suitable populations for FMT. Further investigation is needed to better understand the reasons behind these inconsistent findings and to determine the true potential of FMT as a treatment for IBS.

Gender-specific insights into the irritable bowel syndrome pathophysiology. Focus on gut dysbiosis and permeability

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder involving the brain-gut interaction. IBS is characterized by persistent abdominal pain and changes in bowel habits. IBS exerts significant impacts on quality of life and imposes huge economic costs. Global epidemiological data reveal variations in IBS prevalence, both globally and between genders, necessitating comprehensive studies to uncover potential societal and cultural influences. While the exact pathophysiology of IBS remains incompletely understood, the mechanism involves a dysregulation of the brain-gut axis, leading to disturbed intestinal motility, local inflammation, altered intestinal permeability, visceral sensitivity, and gut microbiota composition. We reviewed several gender-related pathophysiological aspects of IBS pathophysiology, by focusing on gut dysbiosis and intestinal permeability. This perspective paves the way to personalized and multidimensional clinical management of individuals with IBS.

Gut microbiota promotes pain chronicity in Myosin1A deficient male mice

Chronic pain is a heavily debilitating condition and a huge socio-economic burden, with no efficient treatment. Over the past decade, the gut microbiota has emerged as an important regulator of nervous system's health and disease states. Yet, its contribution to the pathogenesis of chronic somatic pain remains poorly documented. Here, we report that male but not female mice lacking Myosin1a (KO) raised under single genotype housing conditions (KO-SGH) are predisposed to develop chronic pain in response to a peripheral tissue injury. We further underscore the potential of MYO1A loss-of-function to alter the composition of the gut microbiota and uncover a functional connection between the vulnerability to chronic pain and the dysbiotic gut microbiota of KO-SGH males. As such, parental antibiotic treatment modifies gut microbiota composition and completely rescues the injury-induced pain chronicity in male KO-SGH offspring. Furthermore, in KO-SGH males, this dysbiosis is accompanied by a transcriptomic activation signature in the dorsal root ganglia (DRG) macrophage compartment, in response to tissue injury. We identify CD206+CD163- and CD206+CD163+ as the main subsets of DRG resident macrophages and show that both are long-lived and self-maintained and exhibit the capacity to monitor the vasculature. Consistently, in vivo depletion of DRG macrophages rescues KO-SGH males from injury-induced chronic pain underscoring a deleterious role for DRG macrophages in a Myo1a-loss-of function context. Together, our findings reveal gene-sex-microbiota interactions in determining the predisposition to injury-induced chronic pain and point-out DRG macrophages as potential effector cells.