Global burden of irritable bowel syndrome: trends, predictions and risk factors

Irritable bowel syndrome and microbiome; Switching from conventional diagnosis and therapies to personalized interventions

The human microbiome has been linked to several diseases. Gastrointestinal diseases are still one of the most prominent area of study in host-microbiome interactions however the underlying microbial mechanisms in these disorders are not fully established. Irritable bowel syndrome (IBS) remains as one of the prominent disorders with significant changes in the gut microbiome composition and without definitive treatment. IBS has a severe impact on socio-economic and patient’s lifestyle. The association studies between the IBS and microbiome have shed a light on relevance of microbial composition, and hence microbiome-based trials were designed. However, there are no clear evidence of potential treatment for IBS. This review summarizes the epidemiology and socioeconomic impact of IBS and then focus on microbiome observational and clinical trials. At the end, we propose a new perspective on using data-driven approach and applying computational modelling and machine learning to design microbiome-aware personalized treatment for IBS.

Efficacy of Probiotics for Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis

Background

Irritable bowel syndrome (IBS) is a common gastrointestinal condition. Studies regarding the treatment of IBS with probiotics have not yielded consistent results, and the best probiotics has not yet been confirmed. Therefore, we performed a network meta-analysis (NMA) to assess the relative rank order of different probiotics for IBS.

Method

We searched for RCTs on the efficacy of probiotics for IBS until August 25, 2021. The primary outcome was the symptom relief rate, as well as global symptoms, abdominal pain, bloating, and straining scores. The NMA was conducted using Stata 15.0. We also used meta-regression to explore whether the treatment length and dose influenced the efficacy.

Results

Forty-three RCTs, with 5,531 IBS patients, were included in this analysis. Firstly, we compared the efficacy of different probiotic species. B.coagulans exhibited the highest probability to be the optimal probiotic specie in improving IBS symptom relief rate, as well as global symptom, abdominal pain, bloating, and straining scores. In regard to the secondary outcomes, L.plantarum ranked first in ameliorating the QOL of IBS patients, but without any significant differences compared with other probiotic species in standardized mean differences (SMD) estimates. Moreover, patients received L.acidophilus had lowest incidence of adverse events. The meta-regression revealed that no significant differences were found between participants using different doses of probiotics in all outcomes, while the treatment length, as a confounder, can significantly influence the efficacy of probiotics in ameliorating abdominal pain (Coef = -2.30; p = 0.035) and straining (Coef = -3.15; p = 0.020) in IBS patients. Thus, we performed the subgroup analysis on treatment length subsequently in these two outcomes, which showed that efficacy of B.coagulans using 8 weeks ranked first both in improving the abdominal pain and straining scores. Additionally, B. coagulans still had significant efficacy compared to different types of probiotic combinations in present study.

Conclusions

The findings of this NMA suggested that B.coagulans had prominent efficacy in treating IBS patients, and incorporating B.coagulans into a probiotic combination, or genetically engineering it to amplify its biological function may be a future research target to treat IBS patients. With few direct comparisons available between individual therapies today, this NMA may have utility in forming treatment guideline for IBS with probiotics.

Baseline Predictors of Discontinuation of Prescription Drug Therapy for IBS-C: Cohort Analysis at an Integrated Healthcare System

BACKGROUND

Effective prescription drug treatment of constipation-predominant irritable bowel syndrome (IBS-C) requires patients to remain on daily therapy, yet predictive factors to optimize treatment selection are unknown.

AIMS

We assessed whether common comorbidities including chronic overlapping pain conditions (COPCs), mood disorders, or concurrent medications influence the risk of discontinuing IBS-C prescription drug therapy.

METHODS

We included all IBS-C patients who initiated treatment with the secretagogues linaclotide or lubiprostone across the Michigan Medicine healthcare system between 2012 and 2016. A Cox proportional hazards model was constructed to model time-to-treatment discontinuation as a valid, quantifiable measure of IBS medication persistence using hazards ratios (HR) with 95% confidence intervals (CI).

RESULTS

Our cohort included 225 patients on linaclotide and 492 on lubiprostone (mean age 48.3 years, 86.9% women, 46.6% with at least one COPC, 60.3% with at least one mood disorder) with an average follow-up of 2.1 years. Patients with at least one COPC (HR = 0.566; 95%CI = 0.371-0.863) and also women (HR = 0.535; 95%CI = 0.307-0.934) had a lower risk of discontinuing linaclotide, while COPCs predicted a trend toward increased discontinuation of lubiprostone (HR = 1.254; 95%CI = 0.997-1.576). Age, comorbid mood disorders, and baseline use of narcotics or benzodiazepines did not significantly mediate the risk of treatment discontinuation; our findings remained stable in univariate and multivariable analyses.

CONCLUSIONS

COPCs and sex appear to influence the likelihood of discontinuation of two commonly prescribed secretagogues, while mood disorders, narcotics, and benzodiazepines may not. Routine assessment for comorbid COPCs prior to initiating therapy may optimize IBS-C treatment selection and outcomes in practice.

The Prevalence and Incidence of Irritable Bowel Syndrome and Inflammatory Bowel Disease in Depression and Bipolar Disorder: A Systematic Review and Meta-Analysis

OBJECTIVE

The increased prevalence and incidence of affective disorders among patients with gastrointestinal disease have been well established. However, few studies have investigated the inverse relationship. We aimed to identify all pieces of evidence of the prevalence and incidence of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) in people with depression and bipolar disorder.

METHODS

We conducted a systematic review of studies reporting the association between affective disorders (exposure) and IBS or IBD (outcome) in adults. Evidence was evaluated for quality using Joanna Briggs Institute Critical Appraisal tools. Where suitable data were available, meta-analyses were performed.

RESULTS

We identified 18 studies that met the selection criteria, of which 11 provided data on IBS, 5 on IBD, and 2 on both. Overall, people with depression were significantly more likely to have comorbid IBS (risk ratio = 2.42, 95% confidence interval = 1.98-2.96) and to develop new-onset IBS (risk ratio = 1.90, 95% confidence interval = 1.41-2.56) compared with people without depression. They were also more likely to have and develop IBD, and among patients with IBD, significantly increased rates of depression were observed as early as 5 years before diagnosis. Bipolar disorder was not consistently associated with risk of either condition.

CONCLUSIONS

People with depression are at an increased risk of both having and developing lower gastrointestinal disorders. These findings have important implications for how we understand, manage, and prevent this comorbidity in clinical practice. Further studies are needed to improve our understanding of the relationship between bipolar disorder and bowel disease as well as the role of psychotropic medication, particularly selective serotonin reuptake inhibitors.

Irritable bowel syndrome and diet

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder (FGID) characterized by chronic abdominal pain and altered bowel habits. The diagnosis of IBS is based on the presence of defined clinical Rome IV criteria in the absence of alarm features. The majority of patients with IBS report of food triggers eliciting typical IBS symptoms and trying to modify their dietary intake.

RECENT FINDINGS

FGID including IBS are defined as disorders of the gut-brain interaction. A large proportion of individuals with IBS link their symptoms to dietary factors, and recent clinical studies have shown benefits of a diet low in FODMAPs (Fermentable Oligo-, Di-, and Monosaccharides and Polyols) on IBS symptoms and quality of life. Dietary interventions mediate directly changes of luminal gut contents affecting chemosensing-enteroendocrine cells in the modulation of the gut brain microbiome axis in IBS patients. Long-term assessment of clinical outcomes in patients on a low FODMAP diet is needed. Professional guidelines have incorporated the suggestion to offer IBS patients a diet low in FODMAPs.

SUMMARY

The FGIDs, including IBS, are defined as gut-brain disorders. Low FODMAP diet has been shown in clinical trials to reduce IBS symptoms but long-term efficacy and nutritional side-effects remain uncertain.

Antibiotics, gut microbiota, and irritable bowel syndrome: What are the relations?

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder in which recurrent abdominal pain is associated with defecation or a change in bowel habits (constipation, diarrhea, or both), and it is often accompanied by symptoms of abdominal bloating and distension. IBS is an important health care issue because it negatively affects the quality of life of patients and places a considerable financial burden on health care systems. Despite extensive research, the etiology and underlying pathophysiology of IBS remain incompletely understood. Proposed mechanisms involved in its pathogenesis include increased intestinal permeability, changes in the immune system, visceral hypersensitivity, impaired gut motility, and emotional disorders. Recently, accumulating evidence has highlighted the important role of the gut microbiota in the development of IBS. Microbial dysbiosis within the gut is thought to contribute to all aspects of its multifactorial pathogenesis. The last few decades have also seen an increasing interest in the impact of antibiotics on the gut microbiota. Moreover, antibiotics have been suggested to play a role in the development of IBS. Extensive research has established that antibacterial therapy induces remarkable shifts in the bacterial community composition that are quite similar to those observed in IBS. This suggestion is further supported by data from cohort and case-control studies, indicating that antibiotic treatment is associated with an increased risk of IBS. This paper summarizes the main findings on this issue and contributes to a deeper understanding of the link between antibiotic use and the development of IBS.

Risk of Colorectal Cancer in Patients With Irritable Bowel Syndrome: A Meta-Analysis of Population-Based Observational Studies

Background and Aims

Evidence on the association between irritable bowel syndrome (IBS) and colorectal cancer (CRC) risk is inconsistent. Therefore, we aimed to examine whether IBS leads to an increased risk for CRC using a systematic review and meta-analysis approach.

Methods

PubMed, Embase, and Web of Science were systematically searched to identify all relevant literature published through July 30, 2021. The pooled risk ratios (RRs) and corresponding 95% confidence intervals (CIs) for CRC after diagnosis of IBS were computed using random-and fixed-effects models and stratified by age, follow-up time, gender, and study design. The quality of included studies was assessed by the Newcastle-Ottawa scale.

Results

We included six studies consisting of 1,085,024 participants. Overall, the risk of detecting CRC after the initial IBS diagnosis was significantly higher than non-IBS controls (RR = 1.52, 95% CI: 1.04-2.22, P = 0.032). The peak of elevated risk occurred within the first year of IBS diagnosis (RR = 6.84, 95% CI: 3.70-12.65, P < 0.001), and after 1 year, the risk of CRC was similar to that of the general population (RR = 1.02, 95% CI: 0.88-1.18, P = 0.813). Notably, we found that the RR of CRC was more significant in IBS patients younger than 50 years compared to those older than 50 years (RR = 2.03, 95% CI: 1.17-3.53, P = 0.012 vs. 1.28, 95%CI: 0.94-1.75, P = 0.118, respectively). Gender and study design did not affect the results.

Conclusion

The risk of CRC within one year of the initial IBS diagnosis was increased approximately six-fold, whereas the long-term risk was not increased. However, current evidence does not support that IBS leads to an increased incidence of CRC, and the early excess risk is more likely attributable to misclassification resulting from overlapping symptoms rather than causation. Clinicians must remain vigilant for the CRC risk in patients younger than 50 years with IBS-like symptoms to avoid delaying necessary screening.

The symptom burden of Irritable Bowel Syndrome in tertiary care during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic caused unprecedented disruption to healthcare services worldwide with well-documented detrimental effects on mental health. Patients with refractory disorders of gut-brain interaction such as Irritable Bowel Syndrome (IBS) seen in tertiary care tend to exhibit higher levels of psychological comorbidity, but the impact of the pandemic on IBS symptom severity in tertiary care is unknown.

METHODS

As part of routine clinical care, consecutive tertiary referrals with refractory IBS patients prospectively completed a series of baseline questionnaires including IBS symptom severity score (IBS-SSS), non-colonic symptom score, Hospital Anxiety and Depression (HAD), and Illness impact scores. The symptom severity questionnaire data were compared for consecutive patients seen in tertiary care 12 months before and after the onset of COVID-19 pandemic restrictions.

KEY RESULTS

Of 190 consecutive tertiary referrals with IBS, those seen during the pandemic had greater IBS severity (IBS-SSS: 352 vs. 318, p = 0.03), more severe extra-intestinal symptoms (non-colonic score: 269 vs. 225, p = 0.03), sleep difficulties (p = 0.03), helplessness and loss of control (p = 0.02), but similar HAD-Anxiety (p = 0.96) and HAD-Depression (p = 0.84) scores. During the pandemic, unmarried patients (p = 0.03), and keyworkers (p = 0.0038) had greater IBS severity.

CONCLUSIONS AND INFERENCES

This study has shown for the first time that patients seen in tertiary care with refractory IBS during the COVID-19 pandemic had a significantly higher symptom burden emphasizing the importance of gut-brain axis in IBS. Furthermore, lack of support and perceived loss of control appear to be contributory factors.

A computer-aid multi-task light-weight network for macroscopic feces diagnosis

The abnormal traits and colors of feces typically indicate that the patients are probably suffering from tumor or digestive-system diseases. Thus a fast, accurate and automatic health diagnosis system based on feces is urgently necessary for improving the examination speed and reducing the infection risk. The rarity of the pathological images would deteriorate the accuracy performance of the trained models. In order to alleviate this problem, we employ augmentation and over-sampling to expand the samples of the classes that have few samples in the training batch. In order to achieve an impressive recognition performance and leverage the latent correlation between the traits and colors of feces pathological samples, a multi-task network is developed to recognize colors and traits of the macroscopic feces images. The parameter number of a single multi-task network is generally much smaller than the total parameter number of multiple single-task networks, so the storage cost is reduced. The loss function of the multi-task network is the weighted sum of the losses of the two tasks. In this paper, the weights of the tasks are determined according to their difficulty levels that are measured by the fitted linear functions. The sufficient experiments confirm that the proposed method can yield higher accuracies, and the efficiency is also improved.

Diet, fibers, and probiotics for irritable bowel syndrome

Many aspects make irritable bowel syndrome (IBS) challenging for both patients and physicians. The unclear pathogenesis with many pathways to be explored, bothering symptoms that affect the quality of life, and many subtypes of the condition are only a few reasons that make IBS difficult to control and obtain satisfactory results. Treatment options start with general advice for lifestyle, continue with non-pharmaceutical treatments, and finally touch classic treatments. In this review, pharmaceutical treatment options are not accounted for. Consensus groups and meta-analyses have concluded guidelines that overall are the same, with variations in the strength of recommendations and some cultural and geographical particularities. Dietary interventions, probiotics, and fibers can be seen as non-pharmaceutical treatments that coexist in various protocols because of the relevant evidence regarding their efficacy in treating IBS symptoms.

Current Treatment Options and Therapeutic Insights for Gastrointestinal Dysmotility and Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) have been re-named as disorders of gut-brain interactions. These conditions are not only common in clinical practice, but also in the community. In reference to the Rome IV criteria, the most common FGIDs, include functional dyspepsia (FD) and irritable bowel syndrome (IBS). Additionally, there is substantial overlap of these disorders and other specific gastrointestinal motility disorders, such as gastroparesis. These disorders are heterogeneous and are intertwined with several proposed pathophysiological mechanisms, such as altered gut motility, intestinal barrier dysfunction, gut immune dysfunction, visceral hypersensitivity, altered GI secretion, presence and degree of bile acid malabsorption, microbial dysbiosis, and alterations to the gut-brain axis. The treatment options currently available include lifestyle modifications, dietary and gut microbiota manipulation interventions including fecal microbiota transplantation, prokinetics, antispasmodics, laxatives, and centrally and peripherally acting neuromodulators. However, treatment that targets the pathophysiological mechanisms underlying the symptoms are scanty. Pharmacological agents that are developed based on the cellular and molecular mechanisms underlying pathologies of these disorders might provide the best avenue for future pharmaceutical development. The currently available therapies lack long-term effectiveness and safety for their use to treat motility disorders and FGIDs. Furthermore, the fundamental challenges in treating these disorders should be defined; for instance, 1. Cause and effect cannot be disentangled between symptoms and pathophysiological mechanisms due to current therapies that entail the off-label use of medications to treat symptoms. 2. Despite the knowledge that the microbiota in our gut plays an essential part in maintaining gut health, their exact functions in gut homeostasis are still unclear. What constitutes a healthy microbiome and further, the precise definition of gut microbial dysbiosis is lacking. More comprehensive, large-scale, and longitudinal studies utilizing multi-omics data are needed to dissect the exact contribution of gut microbial alterations in disease pathogenesis. Accordingly, we review the current treatment options, clinical insight on pathophysiology, therapeutic modalities, current challenges, and therapeutic clues for the clinical care and management of functional dyspepsia, gastroparesis, irritable bowel syndrome, functional constipation, and functional diarrhea.

Association of Migraine and Irritable Bowel Syndrome in Saudi Arabia: A Nationwide Survey

Migraine is a primary headache disorder with a prevalence of 11.6% globally and 27% in Saudi Arabia. Irritable bowel syndrome (IBS) has a prevalence of 9.2% worldwide. The prevalence of IBS has not been established nationally. However, provincial studies for migraine and IBS have been conducted nationwide. There is a significant link between migraine and IBS globally. Migraineurs had a considerably greater prevalence of IBS than nonmigraineurs (OR = 2.49, 95% CI 2.22-2.78). Patients with IBS have 60% higher odds for migraines. This identifies an association that needs to be investigated in a nationwide manner. The study has two main aims. The first is to measure the prevalence of migraine and irritable bowel syndrome in Saudi Arabia. The second is to observe the association and the relationship between migraine and irritable bowel syndrome in Saudi Arabia. A cross-sectional study was conducted among the general population of Saudi Arabia between March 2021 and June 2021, whose ages are 15 years old or greater. Participants filled an online self-administered survey. The data collection tools included the Migraine Screen Questionnaire (MS-Q) for migraine symptoms, migraine severity (MIGSEV) scale for severity of migraine, and the IBS module of the Rome IV Diagnostic Questionnaire (R4DQ) for IBS symptoms and their subtype. With 2802 participants, the majority of the study samples were males, who constituted 52.5%. Among the study's sample, the prevalence of migraine consisted of 27.4%, and the prevalence of IBS was 16.4%. The odds of having IBS in migraineurs were much higher than in those without migraine (OR 4.127; 95% CI 3.325-5.121), and the association was statistically significant (p < 0.001). In conclusion, there is a strong association between migraine and irritable bowel syndrome in Saudi Arabia.

The Role of Carbohydrates in Irritable Bowel Syndrome: Protocol for a Randomized Controlled Trial Comparing Three Different Treatment Options

BACKGROUND

Although it is widely acknowledged that food intake can worsen symptoms in patients with irritable bowel syndrome (IBS), there is a lack of efficient treatments that can apply to all patients and subtypes of IBS. As IBS can manifest in different ways, it is likely that the most successful treatment option will differ among patients; therefore, this large, randomized controlled trial comparing 3 different treatment options for patients with IBS is highly warranted.

OBJECTIVE

This study aims to conduct a randomized controlled trial to evaluate the effectiveness of 3 different treatment options for patients with IBS.

METHODS

A total of 300 patients with IBS will be randomized (1:1:1) to receive one of the following three treatment options: a diet with low total carbohydrate content; a diet combining low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols and traditional dietary advice in IBS; and optimized medical treatment. The study will comprise a 10-day screening period, 28 days of intervention, and a 6-month follow-up for patients receiving dietary treatment. Questionnaires assessing both gastrointestinal and extraintestinal symptoms will be used as end points, as well as metabolomics, microbiota profiling, and immunological markers. Furthermore, qualitative methods will be used to evaluate the patients' experiences regarding diet treatments.

RESULTS

Recruitment for this study began in January 2017. By May 2021, of the proposed 300 participants, 270 (90%) had been randomized, and 244 (81.3%) participants had finished the 4-week intervention. The study is still in progress, and the results are expected to be published in 2022.

CONCLUSIONS

By collecting a wide range of data before, during, and after treatment in a large group of patients with IBS and diverse bowel habits, we will gain new insights into the predictors of response to treatment. That information can, in the future, be used to personalize treatment for the patient, based on the individual's phenotype and IBS symptoms. In addition, the long-term effects of 2 different dietary treatments will be evaluated regarding their impact on gut microbiota and clinical laboratory tests and to ensure that they are safe, effective, and applicable for patients with IBS.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02970591; https://clinicaltrials.gov/ct2/show/NCT02970591.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/31413.

Electroacupuncture Attenuates Post-Inflammatory IBS-Associated Visceral and Somatic Hypersensitivity and Correlates With the Regulatory Mechanism of Epac1-Piezo2 Axis

Electroacupuncture (EA) is considered to have a therapeutic effect in the relief of irritable bowel syndrome (IBS)-associated visceral hypersensitivity via the reduction of the level of 5-hydroxytryptamine (5-HT) and 5-HT₃ receptors (5-HT₃R). However, whether Epac1/Piezo2, as the upstream of 5-HT, is involved in this process remains unclear. We investigated whether EA at the ST36 and ST37 acupoints alleviated visceral and somatic hypersensitivity in a post-inflammatory IBS (PI-IBS) model mice via the Epac1-Piezo2 axis. In this study, we used 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced PI-IBS as a mouse model. Visceral sensitivity was assessed by the abdominal withdrawal reflex test. Somatic sensitivity was evaluated by the hind paw withdrawal threshold. Quantitative real-time PCR, immunofluorescence staining, ELISA, and Western blotting were performed to examine the expressions of Epac1, Piezo2, 5-HT, and 5-HT₃R from the mouse distal colon/L5-S2 dorsal root ganglia (DRG). Our results showed that EA improved the increased visceral sensation and peripheral mechanical hyperalgesia in PI-IBS model mice, and the effects of EA were superior to the sham EA. EA significantly decreased the protein and mRNA levels of Epac1 and Piezo2, and reduced 5-HT and 5-HT₃R expressions in the distal colon. Knockdown of colonic Piezo2 eliminated the effect of EA on somatic hypersensitivity. Combined knockdown of colonic Epac1 and Piezo2 synergized with EA in relieving visceral hypersensitivity and blocked the effect of EA on somatic hypersensitivity. Additionally, protein levels of Epac1 and Piezo2 were also found to be decreased in the L5-S2 DRGs after EA treatment. Taken together, our study suggested that EA at ST36 and ST37 can alleviate visceral and somatic hypersensitivity in PI-IBS model mice, which is closely related to the regulation of the Epac1-Piezo2 axis.

Prevalence and Influencing Factors of Irritable Bowel Syndrome in Medical Staff: A Meta-Analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a common functional digestive tract disease worldwide, with a high prevalence among medical staff. The purpose of this study is to systematically evaluate the prevalence and influencing factors of IBS in medical staff.

METHODS

We searched English online databases, including PubMed, The Cochrane Library, Web of Science, Embase, and EBSCOhost. The retrieval time was from database establishment to May of 2021. We screened the literature according to inclusion and exclusion criteria, extracted the relevant information, and evaluated the research quality. A meta-analysis was performed using the Stata 16.0 and Review Manager 5.4.1 software.

RESULTS

A total of 11 English studies from seven countries were included in this study, including 3,360 medical staff. The results of the meta-analysis showed an overall prevalence of IBS among medical staff of 16% [95%CI (0.15 ~ 0.17)] and that shift work (OR 2.27)), poor sleep quality (OR 4.27), and female gender (OR 2.29) are the major influencing factors of medical staff suffering from IBS.

CONCLUSIONS

The prevalence of irritable bowel syndrome among medical staff is relatively high, and hospitals can start by looking for targeted interventions from the highly related factors of IBS among medical staff such as shift work patterns, females, and poor sleep quality.

The serotonin receptor 3E variant is a risk factor for female IBS-D

Irritable bowel syndrome (IBS) is a gut-brain disorder of multifactorial origin. Evidence of disturbed serotonergic function in IBS accumulated for the 5-HT₃ receptor family. 5-HT₃Rs are encoded by HTR3 genes and control GI function, and peristalsis and secretion, in particular. Moreover, 5-HT₃R antagonists are beneficial in the treatment of diarrhea predominant IBS (IBS-D). We previously reported on functionally relevant SNPs in HTR3A c.-42C > T (rs1062613), HTR3C p.N163K (rs6766410), and HTR3E c.*76G > A (rs56109847 = rs62625044) being associated with IBS-D, and the HTR3B variant p.Y129S (rs1176744) was also described within the context of IBS. We performed a multi-center study to validate previous results and provide further evidence for the relevance of HTR3 genes in IBS pathogenesis. Therefore, genotype data of 2682 IBS patients and 9650 controls from 14 cohorts (Chile, Germany (2), Greece, Ireland, Spain, Sweden (2), the UK (3), and the USA (3)) were taken into account. Subsequent meta-analysis confirmed HTR3E c.*76G > A (rs56109847 = rs62625044) to be associated with female IBS-D (OR = 1.58; 95% CI (1.18, 2.12)). Complementary expression studies of four GI regions (jejunum, ileum, colon, sigmoid colon) of 66 IBS patients and 42 controls revealed only HTR3E to be robustly expressed. On top, HTR3E transcript levels were significantly reduced in the sigma of IBS patients (p = 0.0187); more specifically, in those diagnosed with IBS-D (p = 0.0145). In conclusion, meta-analysis confirmed rs56109847 = rs62625044 as a risk factor for female IBS-D. Expression analysis revealed reduced HTR3E levels in the sigmoid colon of IBS-D patients, which underlines the relevance of HTR3E in the pathogenesis of IBS-D.

The multiple effects of fecal microbiota transplantation on diarrhea-predominant irritable bowel syndrome (IBS-D) patients with anxiety and depression behaviors

BACKGROUND

Anxiety and depression are complications in Irritable bowel syndrome (IBS) patients. In this study, we recruited 18 IBS patients with mild-modest anxiety and depression behaviors, and after the screening, we defined the FMT treatment group (n = 9) and the control group (n = 9). The IBS symptom severity scale (IBS-SSS), Hamilton Anxiety Rating Scale (HAM-A), Hamilton Depression Rating Scale (HAM-D), Irritable Bowel Syndrome Quality of Life (IBS-QOL) and Bristol stool scale (BSS) were evaluated one week before FMT (baseline), one-week-, one-month-, two-month-, and three-month-following FMT. Meanwhile, we determined the SCFAs in the patient's feces and serum and continued the metagenomic analysis of the microorganisms in the patient's feces.

RESULTS

The results showed that the patient's anxiety and depression behavior gradually improved with FMT treatment. Moreover, the illness and quality of life had also been relieved significantly. The content of isovaleric acid and valeric acid was significantly reduced in the FMT group compared to the Col group. Metagenomic analysis showed that FMT treatment decreased the abundance of Faecalibacterium, Eubacterium and Escherichia. From KEGG functional analysis, we confirmed that the top five abundant pathways were "bacterial chemotaxis, "flagellar assembly", "glycine, serine and threonine metabolism", "apoptosis", and "bacterial invasion of epithelial cells".

CONCLUSIONS

FMT treatment can effectively alleviate the anxiety and depression behaviors of IBS-D patients and reduce the IBS-SSS score, indicating that FMT can improve patients' symptoms. The high throughput sequencing results show that Bifidobacterium and Escherichia play the most critical role in the formation and recovery of IBS-D patients. The GC/MS data indicated that faeces isovaleric acid and valeric acid might be more suitable as a metabolic indicator of IBS-D remission. Trial registration ChiCTR, ChiCTR1900024924, Registered 3 August 2019, https://www.chictr.org.cn/showproj.aspx?proj=41676 .

Understanding of the Site-Specific Microbial Patterns towards Accurate Identification for Patients with Diarrhea-Predominant Irritable Bowel Syndrome

Fecal microbial community could not fully represent the intestinal microbial community. However, most studies analyzing diarrhea-dominant irritable bowel syndrome (IBS-D) were mainly based on fecal samples. We aimed to characterize the IBS-D microbial community patterns using samples at multiple intestinal sites. This study recruited 74 IBS-D patients and 20 healthy controls (HC). 22.34%, 8.51%, 14.89%, and 54.26% of them contributed to one, two, three, and four sites: duodenal mucosa (DM), duodenal lumen (DL), rectal mucosa (RM), and rectal lumen (RL) of intestinal samples, respectively. Then 16S rRNA gene analysis was performed on these 283 samples. The result showed that IBS-D microbial communities have specific patterns at each intestinal site differing from that of HC. Across hosts and sites, Bacillus, Burkholderia, and Faecalibacterium were the representative genera in duodenum of IBS-D, duodenum of HC, and rectum of HC, respectively. Samples from mucosa and lumen in rectum were highly distinguishable, regardless of IBS-D and HC. Additionally, IBS-D patients have lower microbial co-abundance network connectivity. Moreover, RM site-specific biomarker: Bacteroides used alone or together with Prevotella and Oscillospira in RM showed outstanding performance in IBS-D diagnosis. Furthermore, Bacteroides and Prevotella in RM were strongly related to the severity of abdominal pain, abdominal discomfort, and bloating in IBS-D patients. In summary, this study also confirmed fecal microbial community could not fully characterize intestinal microbial communities. Among these site-specific microbial communities, RM microbial community would be more applicable in the diagnosis of IBS-D.

IMPORTANCE Microbial community varied from one site to another along the gastrointestinal tract, but current studies about intestinal microbial community in IBS-D were mainly based on fecal samples. Based on 283 intestinal samples collected from DM, DL, RM, and RL of HC and IBS-D, we found different intestinal sites had their site-specific microbial patterns in IBS-D. Notably, RM site-specific microbes Bacteroides, Prevotella, and Oscillospira could be used to discriminate IBS-D from HC accurately. Our findings could help clinicians realize the great potential of the intestinal microbial community in RM for better diagnosis of IBS-D patients.

Interplay between gut microbiota and bile acids in diarrhoea-predominant irritable bowel syndrome: a review

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease that disturbs the physiology and psychology of patients and increases the burden on families, the healthcare system, society, and economic development, affecting more and more people around the world. Despite the multiple factors that account for IBS remaining incompletely studied, emerging evidence demonstrated the abnormal changes in gut microbiota and bile acids (BAs) metabolism closely associated with IBS. Moreover, microbiota drives significant modifications for BAs, consisting of deconjugation, 7α-dehydroxylation, oxidation, epimerization, desulfation, esterification, and so on, while BAs, in turn, affect the microbiota directly or indirectly. In light of the complex connection among gut microbiota, BAs, and IBS, it is urgent to review the latest research progress in this field. In this review, we described the disorders of intestinal microecology and BAs profiles in IBS-D and also highlighted the cross-talk between gut microbiota and BAs in the context of IBS-D. Integrating these, we suggest that new therapeutic strategies targeting the microbiota-BAs axis for IBS-D, even for other related diseases caused by bacteria-bile acid dysbiosis should be expected.

Epidemiology, Clinical Features, and Prescribing Patterns of Irritable Bowel Syndrome in Taiwan

Background: Understanding the prescribing patterns could better inform irritable bowel syndrome (IBS) management and health policy. However, there is no study on prescribing patterns of IBS in Taiwan. This study was conducted to evaluate the epidemiology, clinical features, and prescribing patterns of IBS in Taiwan.

Methods: This population-based cross-sectional study was performed by retrieving claim data from National Health Insurance Research Database (NHIRD) between 2011 and 2018 in Taiwan. Patients who were diagnosed with IBS during 2012–2018 and more than 20 years old were included. The annual incidence and prevalence of IBS were estimated. The characteristics and prescribing pattern were evaluated among IBS population. The population with IBS were followed from index date until 1 year after or death.

Results: A total of 1691596 patients diagnosed with IBS were identified from 2012 to 2018. The average annual incidence and prevalence of IBS in Taiwan were calculated as 106.54 and 181.75 per 10,000 population. The incidence and prevalence showed a decreasing trend from 2012 to 2018. Hypertension, dyslipidemia, chronic liver disease, peptic ulcer, gastroesophageal reflux disease (GERD), anxiety, and sleep disorder were the prevalent comorbidities in IBS population. At 1 year after IBS diagnosis, the rates of peptic ulcer and GERD; the utilizations of abdominal ultrasonography, upper gastrointestinal (GI) endoscopy, and lower GI endoscopy; the prescribing rate of propulsives, simethicone, antacids, H2-blockers, and proton pump inhibitors significantly increased. Approximately 70% of participants received IBS-related treatment. Antispasmodics was the most frequently prescribed medication class, followed by laxatives and antidiarrheals. Only 48.58% of patients made return visit for IBS at 1 year after IBS diagnosis. Consequently, the proportion of consultation for IBS and the prescribing rates of all medications were decreased considerably after IBS diagnosis.

Conclusion: The incidence and prevalence of IBS showed a decreasing trend from 2012 to 2018. More than two-third of patients received treatment for IBS. Antispasmodics was widely used for IBS management. However, patients may have a short symptom duration or receive a short course of IBS-related treatment in Taiwan. These findings provided the whole picture of the epidemiology and prescribing pattern of the IBS population in Taiwan.

Review article: Diagnosis and investigation of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction. It is defined by the Rome criteria as the presence of abdominal pain, related to defaecation, associated with a change in stool form and/or frequency. The approach to diagnosis and investigation of suspected IBS varies between clinicians and, due in part to the uncertainty that can surround the diagnosis, many still consider it to be a diagnosis of exclusion. However, exhaustive investigation is both unnecessary and costly, and may also be counterproductive. Instead, physicians should aim to make a positive diagnosis, based on their clinical assessment of symptoms, and limit their use of investigations. The yield of routine blood tests in suspected IBS is low overall, but normal inflammatory markers may be reassuring. All patients should have serological testing for coeliac disease, irrespective of their predominant stool form. Routine testing of stool microbiology or faecal elastase is unnecessary; however, all patients with diarrhoea aged <45 should have a faecal calprotectin or a similar marker measured which, if positive, should lead to colonoscopy to exclude possible inflammatory bowel disease. Colonoscopy should also be undertaken in any patient reporting alarm symptoms suggestive of colorectal cancer, and in those whose presentation raises suspicion for microscopic colitis. Testing for bile acid diarrhoea should be considered for patients with IBS with diarrhoea where available. Hydrogen breath tests for lactose malabsorption or small intestinal bacterial overgrowth have no role in the routine assessment of suspected IBS. Adopting a standardised approach to the diagnosis and investigation of IBS will help to promote high-quality and high-value care for patients overall.

Review article: epidemiology of IBS and other bowel disorders of gut-brain interaction (DGBI)

The disorders of gut-brain interactions (DGBI) are a spectrum of gastrointestinal (GI) disorders that involve the entire GI tract and are usually categorised into four major anatomic GI regions, oesophageal, gastroduodenal, bowel and anorectal. Irritable bowel syndrome (IBS), a bowel DGBI, is one of the most researched DGBI and has been the subject of copious epidemiological studies. Prevalence rates are based on diagnostic criteria. In the case of IBS, there are three central obstacles to attaining a clear picture of prevalence: the absence of biomarkers, the multitude of diagnostic criteria used over the years, and the heterogeneous nature of the methodology used in epidemiologic surveys. When the results of multiple studies, conducted over a long period of time, using different diagnostic criteria and different research methodology, and involving different study populations are pooled to determine a single summary prevalence rate it is difficult to interpret the results and to determine their reliability and significance. This pitfall is insufficiently recognised and unfortunate because prevalence rates are important for understanding the burden of disease, for allocating healthcare and research resources, and for incentivising and prioritising new treatments. The aims of the present paper are to highlight our knowledge and understanding of IBS epidemiology within the context of other DGBI, and to present strategies to improve epidemiological research, especially in advance of the new Rome V criteria, to be published in 2026.

Cognitive behavioral treatment for irritable bowel syndrome: a recent literature review

Irritable bowel syndrome (IBS) is a gastrointestinal psychosomatic disorder that often develops and worsens with stress. Hence, it is important to treat it from both, its physical and mental aspects. We reviewed recent research on cognitive-behavioral therapy (CBT)—one of the most widely studied psychological treatments for IBS—since it focuses on addressing the cognitions and behaviors associated with IBS symptoms, and combines diverse content, such as cognitive techniques, exposure, stress management, and mindfulness, whose effects have been widely studied. Research on CBT for IBS varies not only in terms of content of the interventions, but also in terms of implementation (individual or group, face-to-face or online). Internet-delivered CBT has recently shown the possibility of providing more accessible and cost-effective psychological intervention to IBS patients in formats, other than face-to-face. In recent years, many standardized scales that allow for IBS-specific psychological assessments have been used in clinical studies of CBT for IBS. Tools that competently deliver effective interventions and properly measure their effectiveness are expected to spread to many people suffering from IBS.

Influence of Irritable Bowel Syndrome on Stress and Depressive Symptoms in Nurses: The Korea Nurses' Health Study

Despite the high risk of irritable bowel syndrome (IBS) and stress/depressive symptoms in nurses, limited research has examined the relationship between these conditions in female nurses. The purpose of this study was to determine the prevalence of IBS and the influence of IBS on stress and depressive symptoms in female nurses. We analyzed the data from the Korea Nurses’ Health Study. Among 7667 participants from the 7th survey conducted from December 2018 to September 2019, 178 nurses were identified as having IBS based on the Rome IV criteria. Using the propensity score matching, 712 were selected as a comparison group. Multivariate ordinal logistic regression analyses were conducted to examine the influence of IBS on stress and depressive symptoms. The prevalence of IBS was 2.3% and the prevalence of depressive symptoms among nurses with IBS was 13.5%. Female nurses with IBS were 2.214 times more likely to experience increased stress levels. However, when demographics, dietary habits, sleep quality, and depressive symptoms were considered, having IBS was no longer an influential factor for increased stress levels. When all the variables were considered, female nurses with IBS were still 2.205 times more likely to experience depressive symptoms. Adequate support is needed to relieve depressive symptoms in nurses with IBS.

Prevalence, clinical characteristics, and management of irritable bowel syndrome in Vietnam: A scoping review

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders worldwide. Its prevalence varies significantly from country to country, largely due to heterogeneity in the available data. Recent studies show that the prevalence of IBS in Asia is on the rise. However, there are very limited data regarding its prevalence in the Vietnamese population. This review aims to offer an overview of the prevalence and clinical characteristics of IBS in the Vietnamese population; and to discuss the current management of IBS in Vietnam-taking into account the available medical resources and the local spectrum of lower gastrointestinal disorders that may mimic IBS.

Intestinal chemosensitivity in irritable bowel syndrome associates with small intestinal TRPV channel expression

BACKGROUND

Irritable bowel syndrome (IBS) patients often experience meal-associated symptoms. However, the underlying mechanisms are unclear.

AIM

To determine small intestinal mechanisms of lipid-induced symptoms and rectal hypersensitivity in IBS METHODS: We recruited 26 IBS patients (12 IBS-C, 14 IBS-D) and 15 healthy volunteers (HV). In vivo permeability was assessed using saccharide excretion assay. Rectal sensitivity was assessed using a barostat before and after small bowel lipid infusion; symptoms were assessed throughout. Next, an extended upper endoscopy with probe-based confocal laser endomicroscopy (pCLE) was performed with changes induced by lipids. Duodenal and jejunal mucosal biopsies were obtained for transcriptomics.

RESULTS

Following lipid infusion, a higher proportion of HV than IBS patients reported no pain, no nausea, no fullness and no urgency (P < 0.05 for all). In a model adjusted for sex and anxiety, IBS-C and IBS-D patients had lower thresholds for first rectal sensation (P = 0.0007) and pain (P = 0.004) than HV. In vivo small intestinal permeability and mean pCLE scores were similar between IBS patients and HV. Post-lipid, pCLE scores were higher than pre-lipid but were not different between groups. Baseline duodenal transient receptor potential vanilloid (TRPV) 1 and 3 expression was increased in IBS-D, and TRPV3 in IBS-C. Duodenal TRPV1 expression correlated with abdominal pain (r = 0.51, FDR = 0.01), and inversely with first rectal sensation (r = -0.48, FDR = 0.01) and pain (r = -0.41, FDR = 0.02) thresholds.

CONCLUSION

Lipid infusion elicits a greater symptom response in IBS patients than HV, which is associated with small intestinal expression of TRPV channels. TRPV-mediated small intestinal chemosensitivity may mediate post-meal symptoms in IBS.

Intestinal microbiota shapes gut physiology and regulates enteric neurons and glia

BACKGROUND

The intestinal microbiota plays an important role in regulating gastrointestinal (GI) physiology in part through interactions with the enteric nervous system (ENS). Alterations in the gut microbiome frequently occur together with disturbances in enteric neural control in pathophysiological conditions. However, the mechanisms by which the microbiota regulates GI function and the structure of the ENS are incompletely understood. Using a mouse model of antibiotic (Abx)-induced bacterial depletion, we sought to determine the molecular mechanisms of microbial regulation of intestinal function and the integrity of the ENS. Spontaneous reconstitution of the Abx-depleted microbiota was used to assess the plasticity of structure and function of the GI tract and ENS. Microbiota-dependent molecular mechanisms of ENS neuronal survival and neurogenesis were also assessed.

RESULTS

Adult male and female Abx-treated mice exhibited alterations in GI structure and function, including a longer small intestine, slower transit time, increased carbachol-stimulated ion secretion, and increased intestinal permeability. These alterations were accompanied by the loss of enteric neurons in the ileum and proximal colon in both submucosal and myenteric plexuses. A reduction in the number of enteric glia was only observed in the ileal myenteric plexus. Recovery of the microbiota restored intestinal function and stimulated enteric neurogenesis leading to increases in the number of enteric glia and neurons. Lipopolysaccharide (LPS) supplementation enhanced neuronal survival alongside bacterial depletion, but had no effect on neuronal recovery once the Abx-induced neuronal loss was established. In contrast, short-chain fatty acids (SCFA) were able to restore neuronal numbers after Abx-induced neuronal loss, demonstrating that SCFA stimulate enteric neurogenesis in vivo.

CONCLUSIONS

Our results demonstrate a role for the gut microbiota in regulating the structure and function of the GI tract in a sex-independent manner. Moreover, the microbiota is essential for the maintenance of ENS integrity, by regulating enteric neuronal survival and promoting neurogenesis. Molecular determinants of the microbiota, LPS and SCFA, regulate enteric neuronal survival, while SCFA also stimulates neurogenesis. Our data reveal new insights into the role of the gut microbiota that could lead to therapeutic developments for the treatment of enteric neuropathies. Video abstract.

Gut Microbiota-Derived Metabolites in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is the most common functional bowel disorder worldwide and is associated with visceral hypersensitivity, gut motility, immunomodulation, gut microbiota alterations, and dysfunction of the brain-gut axis; however, its pathophysiology remains poorly understood. Gut microbiota and its metabolites are proposed as possible etiological factors of IBS. The aim of our study was to investigate specific types of microbiota-derived metabolites, especially bile acids, short-chain fatty acids, vitamins, amino acids, serotonin and hypoxanthine, which are all implicated in the pathogenesis of IBS. Metabolites-focused research has identified multiple microbial targets relevant to IBS patients, important roles of microbiota-derived metabolites in the development of IBS symptoms have been established. Thus, we provide an overview of gut microbiota and their metabolites on the different subtypes of IBS (constipation-predominant IBS-C, diarrhea-predominant IBS-D) and present controversial views regarding the role of microbiota in IBS.

Role of microRNAs in Disorders of Gut-Brain Interactions: Clinical Insights and Therapeutic Alternatives

Disorders of gut–brain interactions (DGBIs) are heterogeneous in nature and intertwine with diverse pathophysiological mechanisms. Regular functioning of the gut requires complex coordinated interplay between a variety of gastrointestinal (GI) cell types and their functions are regulated by multiple mechanisms at the transcriptional, post-transcriptional, translational, and post-translational levels. MicroRNAs (miRNAs) are small non-coding RNA molecules that post-transcriptionally regulate gene expression by binding to specific mRNA targets to repress their translation and/or promote the target mRNA degradation. Dysregulation of miRNAs might impair gut physiological functions leading to DGBIs and gut motility disorders. Studies have shown miRNAs regulate gut functions such as visceral sensation, gut immune response, GI barrier function, enteric neuronal development, and GI motility. These biological processes are highly relevant to the gut where neuroimmune interactions are key contributors in controlling gut homeostasis and functional defects lead to DGBIs. Although extensive research has explored the pathophysiology of DGBIs, further research is warranted to bolster the molecular mechanisms behind these disorders. The therapeutic targeting of miRNAs represents an attractive approach for the treatment of DGBIs because they offer new insights into disease mechanisms and have great potential to be used in the clinic as diagnostic markers and therapeutic targets. Here, we review recent advances regarding the regulation of miRNAs in GI pacemaking cells, immune cells, and enteric neurons modulating pathophysiological mechanisms of DGBIs. This review aims to assess the impacts of miRNAs on the pathophysiological mechanisms of DGBIs, including GI dysmotility, impaired intestinal barrier function, gut immune dysfunction, and visceral hypersensitivity. We also summarize the therapeutic alternatives for gut microbial dysbiosis in DGBIs, highlighting the clinical insights and areas for further exploration. We further discuss the challenges in miRNA therapeutics and promising emerging approaches.

Theories behind the effect of starch‑ and sucrose‑reduced diets on gastrointestinal symptoms in irritable bowel syndrome (Review)

Increased amounts of starch and sugar have been added to the diet in the Western world during the last decades. Undigested carbohydrates lead to bacterial fermentation and gas production with diffusion of water, causing abdominal bloating, pain and diarrhea. Therefore, dietary advice is the first line of treatment of irritable bowel syndrome (IBS), a disease characterized by abdominal pain and altered bowel habits without any organic findings. Recently, a diet with a reduction of starch and sucrose led to a marked effect on gastrointestinal (GI) symptoms. The mechanism is unknown, but three possible mechanisms are presented in the present review. First, functional variants of the enzyme sucrase‑isomaltase (SI) have been described in IBS. A subgroup of patients with IBS may thus suffer from partial SI deficiency with reduced digestion of starch and sucrose. Second, fructose absorption is less efficient than glucose absorption, which may lead to a physiological fructose malabsorption when ingesting high amounts of sucrose. A third mechanism is that high‑sugar diets causing hyperglycemia, hyperinsulinemia and weight gain have led to painful neuropathy in animal models; whereas, improved metabolic control in humans has led to improvement of neuropathy. Starch‑ and sucrose‑reduced diets lead to decreased levels of C‑peptide, insulin, gastric inhibitory peptide, leptin and weight reduction. These metabolic changes may reduce the excitability of the hypersensitive nervous system often found in IBS and, thereby, lead to the reduced symptoms found after the diet. In conclusion, further studies are needed to investigate the pathophysiology behind development of symptoms after starch and sucrose intake, and the mechanisms behind symptom relief after reduced intake.

Vardenafil oral jellies as a potential approach for management of pediatric irritable bowel syndrome

Irritable bowel syndrome (IBS); a widespread disorder in gastrointestinal tract especially in children, burdens their healthcare systems and upsets families. Great attention was paid to understand the pathophysiological cause of disorder. However, developing a convenient treatment especially for children remains a challenge. Phosphodiesterase inhibitors were recently introduced for IBS management. Vardenafil (VDF), a phosphodiesterase-5 inhibitor, exhibiting limited bioavailability when taken orally due to extensive first-pass effect, was the choice for study. This study aimed to formulate VDF jellies as a buccal dosage form to improve pediatric compliance and achieve maximum drug efficacy. VDF oral jellies were prepared by heat and congeal method, and were evaluated for their pH, content uniformity, physical stability, general appearance, and in-vitro drug release. VDF jellies (F1), with satisfactory organoleptic properties and highest percent of drug released compared to other formulations was selected as a master formula for further study to ensure in-vivo efficacy. cyclic Guanosine Mono Phosphate (cGMP), used as indicator of VDF concentration in blood, was highly increased after administration of VDF jellies (F1), compared to oral VDF suspension. Increased defecation with improved fecal consistency strongly favored oral jellies as a potential alternative route for VDF for IBS management with high pediatric acceptance.

Luminal Fluid Motion Inside an In Vitro Dissolution Model of the Human Ascending Colon Assessed Using Magnetic Resonance Imaging

Knowledge of luminal flow inside the human colon remains elusive, despite its importance for the design of new colon-targeted drug delivery systems and physiologically relevant in silico models of dissolution mechanics within the colon. This study uses magnetic resonance imaging (MRI) techniques to visualise, measure and differentiate between different motility patterns within an anatomically representative in vitro dissolution model of the human ascending colon: the dynamic colon model (DCM). The segmented architecture and peristalsis-like contractile activity of the DCM generated flow profiles that were distinct from compendial dissolution apparatuses. MRI enabled different motility patterns to be classified by the degree of mixing-related motion using a new tagging method. Different media viscosities could also be differentiated, which is important for an understanding of colonic pathophysiology, the conditions that a colon-targeted dosage form may be subjected to and the effectiveness of treatments. The tagged MRI data showed that the DCM effectively mimicked wall motion, luminal flow patterns and the velocities of the contents of the human ascending colon. Accurate reproduction of in vivo hydrodynamics is an essential capability for a biorelevant mechanical model of the colon to make it suitable for in vitro data generation for in vitro in vivo evaluation (IVIVE) or in vitro in vivo correlation (IVIVC). This work illustrates how the DCM provides new insight into how motion of the colonic walls may control luminal hydrodynamics, driving erosion of a dosage form and subsequent drug release, compared to traditional pharmacopeial methods.

Enteric Microbiota-Mediated Serotonergic Signaling in Pathogenesis of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional disorder that affects the gastrointestinal tract. Details regarding the pathogenesis of IBS remain largely unknown, though the dysfunction of the brain-gut-microbiome (BGM) axis is a major etiological factor, in which neurotransmitters serve as a key communication tool between enteric microbiota and the brain. One of the most important neurotransmitters in the pathology of IBS is serotonin (5-HT), as it influences gastrointestinal motility, pain sensation, mucosal inflammation, immune responses, and brain activity, all of which shape IBS features. Genome-wide association studies discovered susceptible genes for IBS in serotonergic signaling pathways. In clinical practice, treatment strategies targeting 5-HT were effective for a certain portion of IBS cases. The synthesis of 5-HT in intestinal enterochromaffin cells and host serotonergic signaling is regulated by enteric resident microbiota. Dysbiosis can trigger IBS development, potentially through aberrant 5-HT signaling in the BGM axis; thus, the manipulation of the gut microbiota may be an alternative treatment strategy. However, precise information regarding the mechanisms underlying the microbiota-mediated intestinal serotonergic pathway related to the pathogenesis of IBS remains unclear. The present review summarizes current knowledge and recent progress in understanding microbiome–serotonin interaction in IBS cases.

The Flavonoid Kurarinone Regulates Macrophage Functions via Aryl Hydrocarbon Receptor and Alleviates Intestinal Inflammation in Irritable Bowel Syndrome

Background

Irritable bowel syndrome (IBS) is characterized with abdominal pain, bloating, and changes in bowel habits, and dealing with IBS is still a clinical challenge. The pathogenesis of IBS has been reported to be linked to low-grade mucosal inflammation, and macrophages contribute to the pathological process of this disease. Kurarinone (KAR), a flavanoid derived from Sophora flavescens, has been found medically effective in many inflammatory conditions and cancers. KAR was previously reported to inhibit LPS-induced expression of inflammatory cytokines in macrophages, whether and how KAR regulates the functions of macrophage in IBS remains to be elusive.

Methods

We established a TNBS-induced IBS mouse model, in which KAR was administrated, and mucosal cytokine expression was measured by qRT-PCR. Additionally, mouse macrophages were generated in vitro and their responses to LPS were evaluated by flow cytometry and qRT-PCR. AhR^+/+ or AhR^−/- macrophages were transferred into DTx-treated CD11b-DTR transgenic mice to investigate the role of AhR in IBS. We collected colonic biopsies and peripheral blood samples from 64 patients with IBS, and analyzed AhR expression by qRT-PCR.

Results

We found KAR effectively alleviated visceral hypersensitivity and maintained intestinal barrier functions in mice with IBS. KAR inhibited LPS-induced macrophage activation and expression of pro-inflammatory genes, while increased anti-inflammatory gene expression including IL-10 in an AhR-dependent manner. Using macrophage-depleted mice, we found that chimera mice with AhR^−/- macrophages were more susceptible to TNBS-induced IBS and the therapeutic effect of KAR on IBS was significantly impaired in mice with AhR^−/- macrophages. Additionally, we found AhR expression in macrophages of IBS patients was associated with the disease severity.

Conclusion

Our findings provide new evidences that KAR regulates IBS development via macrophage-intrinsic AhR. KAR might show promise as an immunomodulatory therapeutic agent in treating IBS.

Irritable Bowel Syndrome, Depression, and Neurodegeneration: A Bidirectional Communication from Gut to Brain

Patients with irritable bowel syndrome (IBS) are increasingly presenting with a wide range of neuropsychiatric symptoms, such as deterioration in gastroenteric physiology, including visceral hypersensitivity, altered intestinal membrane permeability, and gastrointestinal motor dysfunction. Functional imaging of IBS patients has revealed several abnormalities in various brain regions, such as significant activation of amygdala, thinning of insular and anterior cingulate cortex, and increase in hypothalamic gray matter, which results in poor psychiatric and cognitive outcomes. Interrelations between the enteric and central events in IBS-related gastrointestinal, neurological, and psychiatric pathologies have compelled researchers to study the gut-brain axis-a bidirectional communication that maintains the homeostasis of the gastrointestinal and central nervous system with gut microbiota as the protagonist. Thus, it can be disrupted by any alteration owing to the gut dysbiosis or loss of diversity in microbial composition. Available evidence indicates that the use of probiotics as a part of a balanced diet is effective in the management of IBS and IBS-associated neurodegenerative and psychiatric comorbidities. In this review, we delineate the pathogenesis and complications of IBS from gastrointestinal and neuropsychiatric standpoints while also discussing the neurodegenerative events in enteric and central nervous systems of IBS patients and the therapeutic potential of gut microbiota-based therapy established on clinical and preclinical data.

Enteric glia in homeostasis and disease: From fundamental biology to human pathology

Glia, the non-neuronal cells of the nervous system, were long considered secondary cells only necessary for supporting the functions of their more important neuronal neighbors. Work by many groups over the past two decades has completely overturned this notion, revealing the myriad and vital functions of glia in nervous system development, plasticity, and health. The largest population of glia outside the brain is in the enteric nervous system, a division of the autonomic nervous system that constitutes a key node of the gut-brain axis. Here, we review the latest in the understanding of these enteric glia in mammals with a focus on their putative roles in human health and disease.

The alternative serotonin transporter promoter P2 impacts gene function in females with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gut-brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation-predominant IBS (IBS-C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta-analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS-C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow-up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS-C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis.

Vitamin D supplementation in people with IBS has no effect on symptom severity and quality of life: results of a randomised controlled trial

Purpose

Several small trials suggest a benefit of vitamin D supplementation in irritable bowel syndrome (IBS). The generalisability of these reports is limited by their design and scale. This study aimed to assess whether vitamin D supplementation improved IBS symptoms in a UK community setting.

Methods

This was a randomised, double-blind, placebo-controlled study. Participants were recruited from the community in winter months between December 2017 and March 2019. 135 participants received either vitamin D (3,000 IU p.d.) or placebo for 12 weeks. The primary outcome measure was change in IBS symptom severity; secondary outcomes included change in IBS-related quality of life.

Results

The participants were analysed on an intent-to-treat basis. 60% of participants were vitamin D deficient or insufficient at baseline. Although vitamin D levels increased in the intervention arm relative to placebo (45.1 ± 32.88 nmol/L vs 3.1 ± 26.15 nmol/L; p < 0.001). There was no difference in the change of IBS symptom severity between the active and placebo trial arms (− 62.5 ± 91.57 vs – 75.2 ± 84.35, p = 0.426) over time. Similarly there was no difference between trial arms in τhe change in quality of life (− 7.7 ± 25.36 vs – 11.31 ± 25.02, p = 0.427).

Conclusions

There is no case for advocating use of vitamin D in the management of IBS symptoms. The prevalence of vitamin D insufficiency suggests routine screening and supplementation should be implemented in this population for general health reasons.

This trial was retrospectively registered with ISRCTN (ISRCTN13277340) on 24th April 2018 after recruiting had been initiated.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02633-w.

Chinese Herbal Medicine for Irritable Bowel Syndrome: A Meta-Analysis and Trial Sequential Analysis of Randomized Controlled Trials

Purpose: Chinese herbal medicine (CHM) is an important complementary and alternative therapy for the management of irritable bowel syndrome (IBS). Previous meta-analyses suggested that CHM is effective for IBS; nonetheless, its effectiveness is inconclusive owing to repeated significance testing. We aimed to examine the efficacy and safety of CHM for IBS through a meta-analysis and trial sequential analysis (TSA).

Methods: We searched OVID Medline, Embase, Cochrane Central Register of Controlled Trials, and Web of Science from January 1, 1980, to September 20, 2020. The primary outcome was adequate relief of global IBS symptoms. The secondary outcomes included relief of abdominal pain and treatment-related adverse events. The relative ratio (RR) and required information size (RIS) were calculated for each outcome.

Results: Ten trials recruiting 2,501 participants were included. Seven (70%) trials were at low risk of bias (RoB). Compared with placebo, CHM was associated with a significantly higher proportion of adequate relief of global IBS symptoms [RR 1.76 (95% confidence interval (95%CI), 1.33–2.33); I² = 81.1%; p < 0.001]. The RIS was 1,083 for the primary outcome, and the accrued information size was 1,716. The analysis of the relief of abdominal pain (three trials with 916 participants) showed similar results compared with placebo [RR 1.85 (95%CI, 1.59–2.14); I² = 0%; p < 0.001; RIS = 197 participants]. CHM was associated with a higher proportion of adverse events compared with placebo [RR 1.51 (95%CI, 1.14–2); I² = 0%; p = 0.004].

Conclusion: CHM was effective in relieving IBS symptoms but caused a higher adverse event rate than placebo. TSA analysis confirmed the findings with sufficient information size.

Parental Response to Only Children: Breaking the Stereotypes

While much has been written about the relationship between only child status and parents' behavior toward children, and consequent personality and intelligence, little is known about the relationship between only child status, parental response to illness, and subsequent child illness behavior. In this study, 227 mothers of 342 children completed measures designed to assess: (a) their children's school attendance, (b) their own psychological status, and (c) their own responses to their children's expressions of stomach pain. Parents of only children were more likely to minimize their children's gastrointestinal symptoms than were parents of children with at least one sibling. In addition, only children were less likely to miss school. Parental protectiveness did not differ as a function of only child status. These findings are somewhat discrepant with commonly held beliefs about parents' patterns of responding to only children.

Oral Versus Gastrointestinal Mucosal Immune Niches in Homeostasis and Allostasis

Different body systems (epidermis, respiratory tract, cornea, oral cavity, and gastrointestinal tract) are in continuous direct contact with innocuous and/or potentially harmful external agents, exhibiting dynamic and highly selective interaction throughout the epithelia, which function as both a physical and chemical protective barrier. Resident immune cells in the epithelia are constantly challenged and must distinguish among antigens that must be either tolerated or those to which a response must be mounted for. When such a decision begins to take place in lymphoid foci and/or mucosa-associated lymphoid tissues, the epithelia network of immune surveillance actively dominates both oral and gastrointestinal compartments, which are thought to operate in the same immune continuum. However, anatomical variations clearly differentiate immune processes in both the mouth and gastrointestinal tract that demonstrate a wide array of independent immune responses. From single vs. multiple epithelia cell layers, widespread cell-to-cell junction types, microbial-associated recognition receptors, dendritic cell function as well as related signaling, the objective of this review is to specifically contrast the current knowledge of oral versus gut immune niches in the context of epithelia/lymphoid foci/MALT local immunity and systemic output. Related differences in 1) anatomy 2) cell-to-cell communication 3) antigen capture/processing/presentation 4) signaling in regulatory vs. proinflammatory responses and 5) systemic output consequences and its relations to disease pathogenesis are discussed.

Study of laxative and hepatoprotective activity of extracts obtained from Prunus domestica fruits

The experimental work focused on the study of the pharmacological properties of extracts obtained from the Prunus domestica fruits to create a prospective laxative drug with moderate hepatoprotective properties. Prunus domestica fruit extracts have been shown to have a pronounced laxative and moderate hepatoprotective effect. Extract containing fibers at a dose of 200 mg/kg was selected as the most active extract for laxative and hepatoprotective activity among all extracts from the Prunus domestica fruits. It was conventionally named “Prunophyte”. Studies of the specific pharmacological action of “Prunophyte” extract in a model of comorbid functional constipation on the background of combined alcoholic liver disease in rats showed that “Prunophyte” at a dose of 200 mg/kg had positive dynamics in the treatment of constipation on the background of subacute liver disease. In some cases it exceeded the effects of combination therapy with drugs “Silibor” at a dose of 25 mg/kg and “Senadexin” at a dose of 14 mg/kg. “Prunophyte” extract, in contrast to “Senodexin”, did not cause signs of diarrhea in animals, which may be a beneficial feature of this drug in subsequent clinical use. This drug has shown that it can be a promising alternative to a one-time complex treatment with herbal laxatives and hepatoprotectors, which will avoid polypragmatism in the treatment of comorbid conditions in gastroenterology associated with functional constipation and liver dysfunction.

Irritable Bowel Syndrome and Coping Strategies: A Cross-sectional Study for Identifying Psychological Alarms and Factors Related to Coping in Riyadh, Saudi Arabia

Psychological alarms including severity of pain, functional impairment, depression, and impaired coping strategies have been correlated with (IBS); however, these attributes, particularly coping strategies, have not been well studied. The aim of this study was to assess psychological alarms, life stressors, and coping strategies of adults diagnosed with IBS. A total of 806 participants completed a self-administered survey consisting of socio-demographic data and life stressors, the Rome IV criteria to diagnose IBS, the Psychological Alarm Questionnaire, and the Coping Strategies Questionnaire (CSQ 24). IBS diagnosis was established among 372 (46.15%) participants. Anxiety (OR = 1.81; 95% CI: 1.35-2.45), severe pain (OR = 1.92; 95% CI: 1.42-2.63), financial life stressors (OR = 1.98; 95% CI: 1.33-2.40), and coping strategies such as reinterpretation (OR = 1.92; 95% CI: 1.39-2.68) and diversion (OR = 2.01; 95% CI: 1.05-3.89) were all significantly and independently associated with IBS diagnosis. Giving the chronic nature of IBS, future research should focus on coping as a potential treatment goal for IBS patients.

Association Between Psychological Disorders and Irritable Bowel Syndrome

Introduction

Irritable bowel syndrome (IBS) is an idiopathic, functional and chronic relapsing disorder. Physiological and psychological variables have been linked with etiology of IBS. In this study, we will determine the prevalence of IBS in local setting and its association with anxiety and depression.

Materials and methods

This cross-section study was conducted in multiple cities of Pakistan. One thousand and seven hundred and sixty (1,760) participants from general population between the age group 18 to 50 were enrolled in the study after informed consent. Diagnosis of IBS was made by assessing participants via ROME III criteria. Hospital anxiety and depression scale (HADS) was used to determine if the participants had anxiety and depression.

Results

IBS was present in 456 (25.9%) participants. IBS was significantly more prevalent in females compared to males. Anxiety was significantly more common in participants with IBS compared to participants without IBS (53.0% vs. 23.0%; p-value < 0.00001). Similarly, depression was significantly more common in participants with IBS (50.6% vs. 21.5%; p-value < 0.00001).

Conclusion

IBS is very common in Pakistan, but rarely diagnosed. It is important anyone, particularly at young age, presenting with diarrhea or constipation should be evaluated for IBS. Simultaneously, patients diagnosed with IBS should be screened for anxiety and depression, and managed accordingly.

Targeted pharmacotherapy of irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal (GI) disorder with negative impact on quality of life and it represents a substantial economic burden on healthcare cost. The medical management of IBS is symptom directed. This review provides an update related to clinical trial data for novel treatment modalities in IBS targeting the gut epithelium secretagogue receptors and channels.

RECENT FINDINGS

The new Rome IV criteria define functional gastrointestinal disorders (FGID) as disorders of the gut-brain interaction. Pharmacological treatment modalities for IBS target gastrointestinal receptors and ion channels, peripheral opioid receptor, gut serotonin receptors, and the gut microbiome. New targeted pharmacotherapies have shown efficacy and safety in the treatment of patients with IBS.

SUMMARY

Diagnostic criteria for FGID, including IBS, have been revised in Rome IV and are defined as gut-brain disorders. Newly approved pharmacotherapy options with proven efficacy and acceptable side-effect profiles are available for the symptom-based management of IBS.