Irritable Bowel Syndrome

2025 Seoul Consensus on Clinical Practice Guidelines for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic, disabling, and functional bowel disorder that significantly affects social functioning and reduces quality of life and increases social costs. The Korean Society of Neurogastroenterology and Motility published clinical practice guidelines on the management of IBS based on a systematic review of the literature in 2017, and planned to revise these guidelines in light of new evidence on the pathophysiology, diagnosis, and management of IBS. The current revised version of the guidelines is consistent with the previous version and targets adults diagnosed with or suspected of having IBS. These guidelines were developed using a combination of de novo and adaptation methods, with analyses of existing guidelines and discussions within the committee, leading to the identification of key clinical questions. Finally, the guidelines consisted of 22 recommendations, including 3 concerning the definition and risk factors of IBS, 4 regarding diagnostic modalities and strategies, 2 regarding general management, and 13 regarding medical treatment. For each statement, the advantages, disadvantages, and precautions were thoroughly detailed. The modified Delphi method was used to achieve expert consensus to adopt the core recommendations of the guidelines. These guidelines serve as a reference for clinicians (including primary care physicians, general healthcare providers, medical students, residents, and other healthcare professionals) and patients, helping them to make informed decisions regarding IBS management.

Developing a core outcome set for nutrition care in adult outpatients with irritable bowel syndrome (COS-RD-IBS study)

BACKGROUND AND AIMS

Irritable bowel syndrome (IBS) is a frequent disorder thought to be caused by a disturbance of the gut-brain axis. Nutrition interventions are an essential pillar of its treatment. However, there is no consensus on which outcomes should be applied to assess the effectiveness of nutrition care in IBS. Standardized outcome sets, or "core outcome sets" (COS), have been proposed to harmonize outcomes in clinical research and practice. This project aims to develop a COS for dietitian-provided nutrition care in adults with IBS or food intolerances with intestinal symptoms, to be implemented in routine outpatient practice.

METHODS

A comprehensive outcomes list was developed based on quantitative and qualitative studies, COS and guidelines on IBS, and important outcomes named by participants. Health service users, dietitians, gastroenterologists, and health care decision makers rated the outcomes in two Delphi survey rounds on their importance and ranked them in a third round. Data was analyzed by panel to account for the different views and sample sizes.

RESULTS

A total of 192 participants registered for the Delphi process. The following 14 outcomes reached consensus in all panels after two rounds: perception of symptom triggering foods/nutrients, intake of trigger foods/nutrients, practicability of diet, adherence, digestive symptoms overall, abdominal pain, abdominal bloating, stool consistency, stool frequency, physical functioning related QoL, nutrition related QoL, social functioning related QoL, empowerment of self-care.

CONCLUSIONS

The Delphi process yielded in a 14 outcomes COS, which exceeds what is typically considered feasible in routine nutrition care. Further work is needed to refine the COS and to identify standardized measurement tools for each outcome.

The case of a bloody mess - Bictegravir/emtricitabine/tenofovir alafenamide induced colitis

BACKGROUND

Fecal calprotectin is a marker used to differentiate inflammatory bowel disease versus irritable bowel syndrome and is relevant in the diagnosis of ulcerative colitis and Crohn's disease. Markedly elevated calprotectin from stool samples provides evidence of colonic inflammation to support the diagnosis of pancolitis. This report is the first to demonstrate the clinical significance of fecal calprotectin in supporting the diagnosis of pancolitis induced by the anti-viral drug, Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide).

CASE REPORT

A 62-year-old male on Biktarvy for his HIV diagnosis was admitted to internal medicine with abdominal pain, bloody diarrhea and pancolitis. His white blood cell count was 15.8 (4.0-11.0x109/L), neutrophil count was 9.7 (2.0-7.5 × 109/L), monocyte count was 1.2 (0.2-0.8 × 109/L), granulocyte count was 1.5 (≤0.1 × 109/L) and hemoglobin was 163 (140-180 g/L). The patient had a C-reactive protein of 229 (≤11.0 mg/L). Serology and blood culture were negative for microbial testing and abdomino-pelvic computed tomography findings were unremarkable. A bloody stool collected had a fecal calprotectin level of 1,159 (<50 µg/g).

CONCLUSIONS

This case highlights how anti-retroviral therapies such as Biktarvy may elicit medication-induced gastrointestinal symptoms, which may underlie the cause of bloody diarrhea and pancolitis, and consequently a grossly elevated fecal calprotectin.

Etiologies of exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI) is a major cause of maldigestion and malnutrition, resulting from primary pancreatic diseases or other conditions. As the prevalence of EPI continues to rise, accurate identification of its etiology has become critical for the diagnosis and treatment of pancreatic secretory insufficiency. EPI can result from both pancreatic and non-pancreatic disorders. Pancreatic disorders include acute and chronic pancreatitis, pancreatic tumors, cystic fibrosis, procedures that involve pancreatic resection, and other rare causes. Non-pancreatic disorders of EPI include diabetes mellitus, celiac disease, inflammatory bowel disease, gastrointestinal and esophagectomy surgery, as well as advanced patient age. This review aims to provide a comprehensive analysis of the literature on EPI etiology, with a thorough overview to support its consideration as a potential diagnosis.

Prevalence of Irritable Bowel Syndrome Based on Rome IV Criteria in Patients in Biochemical and Endoscopic Remission From Newly Diagnosed Inflammatory Bowel Disease: One- and Three-Year Results (the IBSEN III Cohort)

BACKGROUND

Distinguishing irritable bowel syndrome (IBS) from inflammatory bowel disease (IBD) flare-ups is challenging. This study used objective remission markers to accurately determine IBS prevalence in a population-based cohort of patients with IBD.

METHODS

Adults with ulcerative colitis and Crohn's disease were recruited from the IBD in South-Eastern Norway III cohort study. Irritable bowel-like symptoms were assessed using the Rome IV criteria for patients in remission from IBD at 1- and 3-year follow-ups. Remission was defined objectively using the biochemical marker fecal calprotectin (FC) ≤ 250 µg/g, and comparisons to remission based on endoscopic indices were made at 1-year follow-up.

RESULTS

Among patients with FC ≤ 250 µg/g, IBS prevalences were 21.9% (n = 62/283) and 16.1% (n = 49/304) at the 1- and 3-year follow-ups, respectively, which were higher than that in the Norwegian population (9.5%; P < .005). Of patients in endoscopic remission at 1-year follow-up, 19.2% (n = 43/224) reported IBS-like symptoms, which was not significantly different from IBS prevalence for patients with FC ≤ 250 µg/g. Irritable bowel syndrome was independently associated with substantial fatigue (odds ratio: 3.05 [95% CI, 1.48-6.27]) and female sex (odds ratio: 2.67 [95% CI, 1.34-5.32]) at the 1-year follow-up. Patients with IBS reported significantly reduced health-related quality of life (HRQoL) scores.

CONCLUSIONS

The prevalence of IBS among patients in remission from IBD was approximately twice as common as that in the Norwegian population. Irritable bowel syndrome was independently associated with substantial fatigue, female sex, and reduced HRQoL.

Specialty laboratory testing for chronic abdominal pain in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder seen by both primary care providers (PCPs) and gastroenterologists, and further diagnostic testing is generally discouraged unless red-flag symptoms are present.

AIMS

Examine if advanced serologic testing for chronic abdominal pain in IBS patients followed society-specific guidelines and evaluate the diagnostic accuracy of these tests.

METHODS

The study involved a retrospective cross-sectional analysis of adults aged 18 and older who were seen at our institution between 2013 and 2018. Tests included: C1 esterase inhibitor, MEFV gene, urine porphobilinogen, anti-dsDNA, and heavy metal screening. Patients with preexisting rheumatological conditions or diagnoses such as hereditary angioedema, porphyria, familial Mediterranean fever, or lead poisoning were excluded. An appropriateness scale based on disease-specific guidelines was used to evaluate test suitability.

RESULTS

Among 26,732 IBS patients, 143 underwent advanced laboratory testing, with 85.3% ordered by gastroenterologists. Only 12.5% of tests adhered to society-specific guidelines, and the positive test rate was 2.1%. The total cost of testing was $46,542, with $39,007 spent on tests deemed inappropriate.

CONCLUSIONS

The findings emphasize the effectiveness and importance of adhering to Rome IV criteria, as advanced testing often fails to improve diagnostic accuracy and increases unnecessary healthcare costs.

GPR35 agonists inhibit TRPA1-mediated colonic nociception through suppression of substance P release

ABSTRACT

The development of nonopioid analgesics for the treatment of abdominal pain is a pressing clinical problem. To address this, we examined the expression of G i/o -coupled receptors, which typically inhibit nociceptor activation, in colonic sensory neurons. This led to the identification of the orphan receptor GPR35 as a visceral analgesic drug target because of its marked coexpression with transient receptor potential ankyrin 1 (TRPA1), a mediator of noxious mechanotransduction in the bowel. Building on in silico docking simulations, we confirmed that the mast cell stabiliser, cromolyn (CS), and phosphodiesterase inhibitor, zaprinast, are agonists at mouse GPR35, promoting the activation of different G i/o subunits. Pretreatment with either CS or zaprinast significantly attenuated TRPA1-mediated colonic nociceptor activation and prevented TRPA1-mediated mechanosensitisation. These effects were lost in tissue from GPR35 -/- mice and were shown to be mediated by inhibition of TRPA1-evoked substance P (SP) release. This observation highlights the pronociceptive effect of SP and its contribution to TRPA1-mediated colonic nociceptor activation and sensitisation. Consistent with this mechanism of action, we confirmed that TRPA1-mediated colonic contractions evoked by SP release were abolished by CS pretreatment in a GPR35-dependent manner. Our data demonstrate that GPR35 agonists prevent the activation and sensitisation of colonic nociceptors through the inhibition of TRPA1-mediated SP release. These findings highlight the potential of GPR35 agonists to deliver nonopioid analgesia for the treatment of abdominal pain.

Interstitial Cystitis: a phenotype and rare variant exome sequencing study: Interstitial Cystitis: a phenotype and exome sequencing study

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a poorly understood and underdiagnosed syndrome of chronic bladder/pelvic pain with urinary frequency and urgency. Though IC/BPS can be hereditary, little is known of its genetic etiology. Using the eMERGE data, we confirmed known phenotypic associations such as gastroesophageal reflux disease and irritable bowel syndrome and detected new associations, including osteoarthrosis/osteoarthritis and Barrett's esophagus. An exome wide ultra-rare variants analysis in 348 IC/BPS and 11,981 controls extended the previously reported association with ATP2C1 and ATP2A2, implicated in Mendelian desquamating skin disorders, but did not provide evidence for other previously proposed pathogenic pathways such as bladder development, nociception or inflammation. Pathway analysis detected new associations with "anaphase-promoting complex-dependent catabolic process", the "regulation of MAPK cascade" and "integrin binding". These findings suggest perturbations in biological networks for epithelial integrity and cell cycle progression in IC/BPS pathogenesis, and provide a roadmap for its future investigation.

Similarities and Differences in Resting-State Brain Activity Changes of Distinct Chronic Pain Types

OBJECTIVES

To explore neural similarities and differences between visceral and somatic pain by comparing spontaneous brain activity in patients with chronic temporomandibular disorder (TMD) and irritable bowel syndrome (IBS).

METHODS

Twenty eight IBS patients, 21 TMD patients, and 28 healthy controls (HC) underwent resting-state fMRI and behavioral assessments. The correlations between fMRI metrics such as the amplitude of low-frequency fluctuations (ALFF), regional homogeneity (ReHo), functional connectivity (FC), and clinical manifestations were further analyzed.

RESULTS

Compared with HC, both patient groups demonstrated increased ALFF in right parahippocampal gyrus (PHG), insula, medial superior frontal gyrus (SFGmed), precentral gyrus (PreCG), and increased ReHo in right SFGmed and left supplementary motor area (SMA). Compared with IBS patients, TMD patients exhibited reduced ALFF in right SFGmed and insula, increased ALFF in right PHG and PreCG, decreased ReHo in right SFGmed and left lingual gyrus, and increased ReHo in left SMA. Both patient groups exhibited enhanced right PHG-related FC in left precuneus and right cingulate gyrus, and right insula-related FC in left superior temporal gyrus and right paracentral lobule. Specifically, IBS patients showed higher FC between right PHG and orbitofrontal cortex than TMD patients, which was negatively correlated with mood and gastrointestinal symptoms. Mediation analysis revealed that pain in TMD and gastrointestinal symptoms in IBS mediated these relationships.

CONCLUSION

Visceral and somatic pain share abnormal activity in multiple brain networks. Abnormalities in affective region present potential neuroimaging markers for pain disorders, with depression in somatic pain linked to pain intensity and in visceral pain to gastrointestinal symptoms.

Effects of Probiotics and Diet Management in Patients With Irritable Bowel Syndrome: A Systematic Review and Network Meta-analysis

CONTEXT

The efficacy of probiotics and diet management in irritable bowel syndrome (IBS) is controversial, and their relative effectiveness remains unclear.

OBJECTIVE

This study aimed to evaluate the effects of probiotics, diet management, and their combination on IBS.

DATA SOURCES

PubMed, Embase, Cochrane, and Web of Science were searched from inception to July 10, 2023, for relevant studies, including symptom relief, IBS-symptom severity score (-SSS), and IBS-quality of life measure (-QOL).

DATA EXTRACTION

Two investigators independently performed the data extraction and quality assessment.

DATA ANALYSIS

A network meta-analysis was performed using a frequentist approach and a random-effects model to estimate the relative risk (RR) and 95% CI.

RESULTS

Forty-four articles were eligible for this study. In relieving IBS symptoms, compared with a sham diet, a low-fermentable oligosaccharide, disaccharide, monosaccharide, and polyols (low-FODMAP) diet (RR: 3.22; 95% CI: 1.70-6.26) and low-FODMAP diet combined with probiotics (RR: 17.79; 95% CI: 3.27-112.54) significantly relieved IBS symptoms. The control group showed significantly lower effectiveness than the probiotics group (RR: 0.47; 95% CI: 0.32-0.69). According to the surface under the cumulative rank curve (SUCRA), a low-FODMAP diet combined with probiotics (80.4%) had the best effect in relieving IBS symptoms, followed by a low-FODMAP diet (70.8%), probiotics (65.1%), and a gluten-free diet (54.3%). In reducing the total IBS-SSS, the low-FODMAP diet (90.5%) was the most effective, followed by the low-FODMAP diet combined with probiotics (76.6%), probiotics alone (62.3%), and gluten-free diet (28.3%). In reducing total IBS-QOL, probiotics (72.1%) ranked first, followed by gluten-free (57.0%) and low-FODMAP (56.9%) diets. Probiotics (34.9%) were associated with the lowest risk of adverse effects.

CONCLUSION

A low-FODMAP diet combined with probiotics is most effective in relieving IBS symptoms. A low-FODMAP diet is the most recommended diet for alleviating IBS severity, and probiotics were associated with improving the QOL of patients with IBS, with the fewest adverse events.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42024499113.

The association between oxidative balance score with constipation and diarrhea in US adults: a cross-sectional analysis of NHANES 2007-2010

BACKGROUND

Oxidative stress is associated with functional bowel disorders. The Oxidative Balance Score (OBS) is used to represent the overall level of oxidative stress experienced by an individual. Sex differences are exhibited in the occurrence of constipation and diarrhea. This population-based study aimed to examine the association between the OBS, constipation, and diarrhea, among adults in the United States (US), stratified by sex.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) database spanning from 2007 to 2010, a cross-sectional study including 4,462 participants (2,386 males and 2,076 females) was performed to assess the relationship between the OBS, constipation, and diarrhea, among adult men and women in the US. Constipation and diarrhea were identified according to bowel frequency and stool type, as outlined in the Bowel Health Questionnaire. The independent variable was the OBS based on 20 types of dietary and lifestyle components. We conducted a binary logistic regression subgroup analysis by sex, and a univariate subgroup analysis; and used a restricted cubic spline (RCS) to illustrate the relationship between the OBS and abnormal bowel health.

RESULTS

After adjusting for all covariates, a multivariate binary logistic regression analysis revealed that the OBS was negatively correlated with constipation in males [odds ratios (OR) (95% confidence intervals (CI)): 0.937 (0.888, 0.988), P = 0.017], and diarrhea in females [OR (95%CI): 0.951 (0.916, 0.987), P = 0.009]. RCS analysis identified a negative linear trend between OBS and constipation in males (P for non-linearity = 0.63), as well as between OBS and diarrhea in females (P for non-linearity > 0.05).

CONCLUSION

The current study found a negative correlation between the OBS and the risk of constipation in males, along with diarrhea in females. Oxidative stress, gut microbiota, and sex differences may be associated with intestinal dysfunction. These findings suggest that antioxidant-rich dietary modifications may be an effective strategy for preventing constipation in males and diarrhea in females.

Stress triggers irritable bowel syndrome with diarrhea through a spermidine-mediated decline in type I interferon

Irritable bowel syndrome with diarrhea (IBS-D) is a common and chronic gastrointestinal disorder that is characterized by abdominal discomfort and occasional diarrhea. The pathogenesis of IBS-D is thought to be related to a combination of factors, including psychological stress, abnormal muscle contractions, and inflammation and disorder of the gut microbiome. However, there is still a lack of comprehensive analysis of the logical regulatory correlation among these factors. In this study, we found that stress induced hyperproduction of xanthine and altered the abundance and metabolic characteristics of Lactobacillus murinus in the gut. Lactobacillus murinus-derived spermidine suppressed the basal expression of type I interferon (IFN)-α in plasmacytoid dendritic cells by inhibiting the K63-linked polyubiquitination of TRAF3. The reduction in IFN-α unrestricted the contractile function of colonic smooth muscle cells, resulting in an increase in bowel movement. Our findings provided a theoretical basis for the pathological mechanism of, and new drug targets for, stress-exposed IBS-D.

Irritable Bowel Syndrome (IBS) and Smoking: An Evaluation of IBS symptom severity and anxiety sensitivity among adults in the United States

INTRODUCTION

Irritable bowel syndrome (IBS) is a prevalent disorder of gut-brain function associated with psychological distress as well as work and quality of life impairment. Smoking has been linked to gastrointestinal dysfunction, however, research focused on the prevalence of IBS and smoking is limited. Previous research has shown that anxiety sensitivity is linked to increased risk of aversive bodily experiences and subsequent coping-oriented regulation efforts. Higher anxiety sensitivity has also been associated with processes linked to tobacco cigarette smoking lapse and relapse. There is a need to clarify the explanatory roles of anxiety sensitivity in the context of more severe IBS symptoms among persons with IBS who are current smokers.

METHOD

The present investigation evaluated the main and interactive effects of IBS symptom severity and anxiety sensitivity in relation to processes related to the maintenance and relapse of tobacco smoking among adults with IBS. The sample consisted of 263 (52.1 % female; Mage = 44.13 years, SD = 12.71) adults who met criteria for IBS and smoke at least 5 cigarettes per day.

RESULTS

Hierarchical regression results indicated that both anxiety sensitivity and IBS symptom severity independently predicted greater perceived barriers to smoking cessation, severity of problems experienced during quitting, and negative reinforcement smoking expectancies. A statistically significant interaction further indicated that IBS symptom severity was more strongly associated with negative reinforcement smoking expectancies among participants with higher, relative to lower, anxiety sensitivity.

CONCLUSIONS

This study is the first to show that both IBS symptom severity and anxiety sensitivity are related to greater perceived barriers to smoking cessation, previous difficulty quitting, and negative reinforcement expectancies among adults with IBS. There is a continued need to further scientific understanding of interrelations between anxiety sensitivity, IBS symptom severity, and smoking cessation-related beliefs and processes to identify novel approaches that can best support quitting among this understudied population.

The Efficacy of the Low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) Diet in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Irritable bowel syndrome (IBS) is frequently observed in clinical practice and affects people from different parts of the world. The pathogenesis and aetiology are not well-defined or fully understood; however, altered bowel movements, psychological factors, and visceral hypersensitivity may contribute to symptoms via a pathway mediated by serotonin and other enteric neurotransmitters. Altered bowel movements, including diarrhoea and constipation, abdominal pain relieved by passing flatus, and bloating are the main salient features of this condition. This systematic review and meta-analysis aimed to determine the effectiveness and efficacy of a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (low-FODMAP) diet in these patients. Systematic searches were conducted on PubMed, Medline, Google Scholar, and Cochrane Library. Randomised controlled trials (RCTs), systematic trials and cohort studies that included keywords about IBS and a low-FODMAP diet were included. Exclusion criteria included studies that were not in the English language, not relevant to IBS, diet-related to inflammatory bowel disease, or not pertinent to the subject. A total of 41 studies were included in this systematic review and meta-analysis. There was significant heterogeneity among the RCTs; hence, a random-effects model was used. The systematic review included a total of 8460 patients across 36 studies, with follow-up durations ranging from 11 to 16 months. Specifically, the meta-analysis included 15 RCTs with 1118 participants and follow-up durations from two days to nine weeks and six cohort studies including 292 patients with follow-up durations from two weeks to two years. The risk ratio (RR) was 1.21 (95% confidence interval= 0.98-1.51), and the I2 value ​​​​​was 63% for global symptom improvement with a low-FODMAP diet using a random-effects model. There was a low risk of bias in the RCTs. Five studies were included evaluating the effect of a low-FODMAP diet on quality of life, and these studies did not show any statistically significant benefit of a low-FODMAP diet on quality of life, although a mean difference of 4.59 (95% CI 1.50-7.67) was observed. The risk of bias was moderate to severe in the observational studies included in this review. Food intolerance is increasingly recognised as a contributory factor in IBS, and its role in the pathogenesis and precipitation of symptoms is being explored. Specific mechanisms include the fermentation of FODMAPs by the gut microbiota, leading to gas production and subsequent symptoms.

Unraveling the genetic susceptibility of irritable bowel syndrome: integrative genome-wide analyses in 845 492 individuals: a diagnostic study

BACKGROUND

Irritable bowel syndrome (IBS) significantly impacts individuals due to its prevalence and negative effect on quality of life. Current genome-wide association studies (GWAS) have only identified a small number of crucial single nucleotide polymorphisms (SNPs), not fully elucidating IBS's pathogenesis.

OBJECTIVE

To identify genomic loci at which common genetic variation influences IBS susceptibility.

METHODS

Combining independent cohorts that in total comprise 65 840 cases of IBS and 788 652 controls, the authors performed a meta-analysis of genome-wide association studies (GWAS) of IBS. The authors also carried out gene mapping and pathway enrichment to gain insights into the underlying genes and pathways through which the associated loci contribute to disease susceptibility. Furthermore, the authors performed transcriptome analysis to deepen their understanding. IBS risk models were developed by combining clinical/lifestyle risk factors with polygenic risk scores (PRS) derived from the GWAS meta-analysis. The authors detect the phenotype association for IBS utilizing PRS-based phenome-wide association (PheWAS) analyses, linkage disequilibrium score regression, and Mendelian randomization.

RESULTS

The GWAS meta-analysis identified 10 IBS risk loci, seven of which were novel (rs12755507, rs34209273, rs34365748, rs67427799, rs2587363, rs13321176, rs1546559). Multiple methods identified nine promising IBS candidate gene ( PRRC2A, COP1, CADM2, LRP1B, SUGT1, MED12L, P2RY14, PHF2, SHISA6 ) at 10 GWAS loci. Transcriptome validation also revealed differential expression of these genes. Phenome-wide associations between PRS-IBS and nine traits (neuroticism, diaphragmatic hernia, asthma, diverticulosis, cholelithiasis, depression, insomnia, COPD, and BMI) were identified. The six diseases (asthma, diaphragmatic hernia, diverticulosis, insomnia major depressive disorder and neuroticism) were found to show genetic association with IBS and only major depressive disorder and neuroticism were found to show causality with IBS.

CONCLUSION

The authors identified seven novel risk loci for IBS and highlighted the substantial influence on genetic risk harbored. The authors' findings offer novel insights into etiology and phenotypic association of IBS and lay the foundation for therapeutic targets and interventional strategies.

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.

Intestinal epithelial glycocalyx and intestinal disease

With the continuous research on glycobiology, more and more diseases are found to be associated with the glycocalyx. Glycocalyx can be categorized as endothelial glycocalyx and epithelial glycocalyx. Past studies mostly target endothelial glycocalyx, and this review focuses on the structure and function of intestinal epithelial glycocalyx, its degradation mechanism and biological relevance to different diseases of the intestinal tract, as well as the targeted delivery of drugs to organs by nanoparticle libraries mimicking the glycocalyx, in order to provide a theoretical basis for the study of potential diagnostic markers and therapeutic targets of intestinal epithelial glycocalyx in intestinal diseases.

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

Introduction: Irritable bowel syndrome (IBS) is a common condition that alters the quality of life of patients. A variety of dietary interventions have been introduced to address this debilitating condition. The low-FODMAP diet (LFD), gluten-free diet (GFD), and Mediterranean diet are examples showing efficacy. The aim of this network meta-analysis was to compare these interventions to find the best approach. Methods: We performed a systematic review of the available literature through 14 March 2024 in the following databases: Embase, PubMed, MEDLINE OVID, Web of Science, CINAHL Plus, and Cochrane Central. We only included randomized controlled trials (RCTs). We used a random effects model and conducted a direct meta-analysis based on the DerSimonian-Laird approach and a network meta-analysis based on the frequentist approach. Mean differences (MDs) with 95% confidence interval (CI) were calculated. The primary outcomes included IBS quality of life (IBS QOL) and IBS symptom severity scale (IBS-SSS). Results: We finalized 23 studies including 1689 IBS patients. In the direct meta-analysis, there was no statistically significant difference in any IBS score between GFD and either LFD or standard diet. Meanwhile, the LFD was statistically superior to the standard diet in the IBS-SSS (MD: -46.29, CI: -63.72--28.86, p < 0.01) and IBS QOL (MD: 4.06, CI: 0.72-7.41, p = 0.02). On ranking, the Mediterranean diet showed the greatest improvement in IBS-SSS, IBS-QOL, distension, dissatisfaction, and general life interference, followed by the LFD alone or in combination with the GFD. Conclusions: We demonstrated the efficacy of dietary interventions such as the LFD and Mediterranean diet in improving IBS. There is a need for large RCTs with head-to-head comparisons, particularly for the Mediterranean diet.

Overexpression of MCL1 attenuates irritable bowel syndrome by regulating cuproptosis: Screening and validation

Irritable bowel syndrome (IBS) is a type of chronic bowel disorder with a poorly understood pathophysiology. Recently, the imbalance of copper has been reported to influence the progression of IBS, suggesting cuproptosis, a new type of copper-induced cell death, may play a role in IBS. This study found 17 cuproptosis-related differentially expressed genes in IBS through bioinformatic analysis. Six hub genes were identified after the protein-protein interaction network analysis, namely myeloid cell leukemia 1 (MCL1), epidermal growth factor receptor 2, cadherin-associated protein beta 1, solute carrier family 25 members 37, solute carrier family 39 members 14, and six transmembrane epithelial antigens of the prostate 3. We selected MCL1 for further verification. Human normal colon epithelial cell line (NCM460) was used to construct models of IBS or cuproptosis in vitro by lipopolysaccharide (LPS) or LPS combined with copper (II) chloride (CuCl2). We observed that overexpression of MCL1 promoted cell viability and proliferation ability, and inhibited the secretion of inflammatory factors and expression of Bax and caspase-3 of NCM460 cells treated with LPS or LPS combined with CuCl2. In addition, up-regulated MCL1 significantly suppressed the protein levels of ferredoxin 1 and lipoyl synthase, two key regulators of cuproptosis. In conclusion, our study demonstrates that cuproptosis is involved in IBS and identifies a cuproptosis-related gene, MCL1, that helps alleviate IBS by promoting cell growth, reducing inflammation, and suppressing cuproptosis, making it a promising therapeutic target in IBS.

Differences in clinical manifestations and the fecal microbiome between irritable bowel syndrome and small intestinal bacterial overgrowth

BACKGROUND

Irritable bowel syndrome (IBS) and small intestinal bacterial overgrowth (SIBO) share similar abdominal symptoms; however, their differentiation remains controversial.

AIMS

To illustrate the differences between the two conditions.

METHODS

Patients and healthy controls completed questionnaires and provided stool samples for analysis.

RESULTS

IBS presented with the most severe symptoms and was specifically characterized by intense abdominal pain and frequent episodes of diarrhea. Patients with IBS displayed more dysregulated taxonomy within the fecal microbiota than SIBO. Opportunistic pathogens, including Lachnoclostridium, Escherichia-Shigella, and Enterobacter were enriched in the IBS group which contributed to increased bacterial pathogenicity and positively correlated with abdominal pain and bloating, meanwhile, Lachnoclostridium and Escherichia-Shigella were found to be associated with metabolites affiliated to bile acids, alcohols and derivatives. Bacteria enriched in SIBO group correlated with constipation. The bacterial co-occurrence network within the SIBO group was the most intricate. Ruminococcaceae Group were defined as core bacteria in SIBO. Differential metabolites affiliated to androstane steroids and phenylacetic acids were associated with core bacteria.

CONCLUSIONS

Our study elucidates the differences between IBS and SIBO in terms of symptoms, microbiota and functions, which provides insights into a better understanding of both diseases and evidence for different treatment strategies.

Tea-derived exosome-like nanoparticles prevent irritable bowel syndrome induced by water avoidance stress in rat model

BACKGROUND AND AIM

Exosome-like nanoparticles (ELNs) have emerged as crucial mediators of intercellular communication, evaluated as potential bioactive nutraceutical biomolecules. We hypothesized that oral ELNs have some therapeutic effect on irritable bowel syndrome (IBS).

METHODS

In our study, ELNs from tea (Camellia sinensis) leaves were extracted by differential centrifugation. We investigated the role of ELNs by assessing visceral hypersensitivity, body weight, bowel habits, tight junctions, and corticotropin-releasing hormone (CRH) in rats subjected to water avoidance stress (WAS) to mimic IBS with and without ELNs (1 mg/kg per day) for 10 days.

RESULTS

The average diameter of ELNs from LCC, FD and MZ tea tree were 165 ± 107, 168 ± 94, and 168 ± 108 nm, the concentration of ELNs were 1.2 × 1013, 1 × 1013, and 1.5 × 1013 particles/mL, respectively. ELNs can be taken up by intestinal epithelial cells. In WAS rats, ELNs significantly restored weight, recovered tight junctions, decreased CRH, and CRH receptor 1 expression levels and inhibited abdominal hypersensitivity in comparison to positive control.

CONCLUSIONS

Oral tea-derived ELN improves symptoms of IBS by potentially modulating the CRH pathway.

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.

WenTongGanPi decoction alleviates diarrhea-predominant irritable bowel syndrome by improving intestinal barrier

ETHNOPHARMACOLOGICAL RELEVANCE

WenTongGanPi Decoction (WTGPD) is a representative medical practice of the Fuyang School of Traditional Chinese Medicine (TCM), which originated from the classical Lu's Guizhi method. WTGPD places emphasis on the balance and functionality of yang qi, and is effective in treating TCM symptoms related to liver qi stagnation and spleen yang deficiency. In TCM, diarrhea-predominant irritable bowel syndrome (IBS-D) is often diagnosed as liver depression and spleen deficiency, and the use of WTGPD has shown significant therapeutic effect. However, the underlying mechanism of WTGPD treating IBS-D remains unclear.

AIM OF THE STUDY

To explore the effect and mechanism of WTGPD in the treatment of IBS-D.

MATERIALS AND METHODS

An IBS-D model with liver depression and spleen deficiency was constructed by chronic immobilization stress stimulation and sennae folium aqueous gavage. The impact of WTGPD on IBS-D rats was evaluated through measurements of body weight, fecal water content, and abdominal withdrawal reflex (AWR). Intestinal permeability was assessed using hematoxylin-eosin (HE), alcian blue-periodic acid schiff (AB-PAS), immunofluorescence (IF) staining, and quantitative real-time PCR (qRT-PCR). The components of WTGPD were analyzed using UPLC-Q-TOF-MS. The underlying mechanisms were investigated through network pharmacology, transcriptomics sequencing, western blot (WB), molecular docking, and 16S rRNA sequencing.

RESULTS

WTGPD treatment effectively alleviated diarrhea and abnormal pain in IBS-D rats (P < 0.05). It enhanced the intestinal barrier function by improving colonic structure and increasing the expression of tight junction proteins (P < 0.05). A total of 155 components were identified in WTGPD. Both network pharmacology and transcriptomics sequencing analysis highlighted MAPK as the key signaling pathway in WTGPD's anti-IBS-D effect. The WB results showed a significant decrease in p-p38, p-ERK and p-JNK expression after WTGPD treatment (P < 0.0001). Guanosine, adenosine and hesperetin in WTGPD may be involved in regulating the phosphorylation of p38, ERK and JNK. Additionally, WTGPD significantly enhanced microbial diversity and increased the production of colonic valeric acid in IBS-D rats (P < 0.01).

CONCLUSION

In conclusion, our findings suggest that WTGPD can effectively alleviate IBS-D and improve intestinal barrier likely via inhibiting MAPK signal pathway and improving micobial dysbiosis.

The Value of PHQ-9 and GAD-7 for Screening Emotional Disorders in IBS-D and the Specificity of the Gut Flora Associated with Emotional Comorbidity: Preliminary Findings

Background

To identify irritable bowel syndrome with diarrhea (IBS-D) combined with anxiety and/or depression through a psychological screening tool and to further explore the relationships between patients with comorbidities and gut microbiota.

Methods

The GAD-7, SAS, PHQ-9 and SDS were administered to evaluate anxiety and depression. Faeces were subsequently collected from 44 patients with emotional disorders (IBS-EDs), 22 patients without emotional disorders (IBS-nEDs) and 18 healthy controls (HCs) via 16S rRNA sequencing, depending on the participants' wishes. The differences in gut microbiota among different groups were analysed. Spearman analysis was conducted at the genus level and was based on psychological assessment scores. Patients with IBS-D were recruited from December 2020 to November 2022.

Results

This study included 124 outpatients with IBS-D. According to the GAD-7 and SAS scores, 40.3% and 19.3% of the participants, respectively, had anxiety (P < 0.05). Similarly, a significantly greater percentage of participants had depression according to the PHQ-9 than according to the SDS (61.3% vs 33.1%) (P < 0.05). Overall, approximately 66.1% of the participants had emotional disorders (anxiety and/or depression) according to the GAD-7 and PHQ-9. Correlation analysis revealed that the abundances of Eubacterium_hallii_group, Monoglobus and Lachnoclostridium were closely related to the PHQ-9 scores and that the abundances of Subdoligranulum and Holdemanella were closely related to the GAD-7 scores.

Conclusion

In comparison to the SAS and SDS, both the GAD-7 and PHQ-9 identified a greater number of individuals with emotional disorders within the IBS-D population. Furthermore, our findings demonstrated that Lachnoclostridium is not only a biomarker for IBS-ED patients but also that its abundance changes are related to PHQ-9 scores, which may provide insights for further brain gut investigations.

6-Shogaol Derived from Ginger Inhibits Intestinal Crypt Stem Cell Differentiation and Contributes to Irritable Bowel Syndrome Risk

Dietary factors play a crucial role in irritable bowel syndrome (IBS) pathogenesis. Therefore, the dietary contraindications for patients with IBS require further supplementation. Recent investigations have revealed that ginger consumption may pose a risk of aggravating the symptoms and incidence of IBS; however, the specific mechanism remains unknown. In this study, we developed experimental IBS and intestinal organoid differentiation screening models to elucidate the mechanisms underlying the ginger-mediated exacerbation of IBS symptoms. Subsequently, we used a knockout approach combined with click chemistry as well as virus infection to identify the toxic components of ginger and the target mechanism. Our results showed that a daily intake of 90 to 300 mg/kg ginger (equivalent to a human daily dose of 0.6 to 2 g per person) may pose a risk of exacerbating IBS symptoms. Furthermore, a component derived from 6-gingerol (ginger's main ingredient) through in vivo gastric acid and heat processing inhibited the formation of the eIF3 transcription initiation complex by covalently binding to the Cys58 site of eIF3A, a key factor regulating intestinal crypt stem cell differentiation, further reducing the goblet cell number and related mucus layer thickness and increasing lipopolysaccharide infiltration and low-grade inflammation in the ileum crypts, thereby exacerbating the symptoms of IBS in mice. Our study suggests that dietary ginger aggravates IBS and provides safety evaluation methods for the proper use of foods in specific populations.

Somatization Mediates the Relationship Between Childhood Trauma and Pain Ratings in Patients with Irritable Bowel Syndrome

GOALS

To identify potential mechanisms by which childhood trauma may lead to the adult development of abdominal symptoms in patients with irritable bowel syndrome (IBS).

BACKGROUND

Patients with IBS frequently report a history of childhood trauma. The pathophysiology by which abdominal pain arises in patients with IBS is multidimensional, consisting of both peripheral factors, such as altered motility, inflammation, and bacterial overgrowth, as well as central factors, such as psychological distress and neuro-hormonal dysregulation.

STUDY

Adult psychological factors (anxiety, depression, and somatization) were examined to determine if they mediate the relationship between retrospective reports of childhood trauma and current adult IBS abdominal symptoms in a study of 436 patients (M age=41.6, 79% F) meeting Rome III diagnosis criteria. Childhood trauma was measured using retrospective questions assessing physical and sexual abuse. Psychological factors in adulthood were measured with the subscales of the Brief Symptom Inventory-18. Outcome variables included adult IBS symptoms of abdominal pain, bloating, and satisfaction with bowel habits from the IBS Symptoms Severity Scale.

RESULTS

Results indicated that somatization mediated the relationship between childhood abuse and abdominal pain and bloating but not bowel satisfaction.

CONCLUSIONS

This study provides insight into the multifactorial nature of IBS-associated abdominal pain in patients with a history of childhood trauma, elucidating the need for a trauma-informed treatment approach for patients with histories of abuse.

Molecular Mechanisms Underlying Loss of Vascular and Epithelial Integrity in Irritable Bowel Syndrome

BACKGROUND & AIMS

The pathophysiology of irritable bowel syndrome (IBS) is multifactorial and includes epithelial barrier dysfunction, a key element at the interface between the gut lumen and the deeper intestinal layers. Beneath the epithelial barrier there is the vascular one representing the last barrier to avoid luminal antigen dissemination The aims of this study were to correlate morpho-functional aspects of epithelial and vascular barriers with symptom perception in IBS.

METHODS

Seventy-eight healthy subjects (controls) and 223 patients with IBS were enrolled in the study and phenotyped according to validated questionnaires. Sugar test was used to evaluate in vivo permeability. Immunohistochemistry, western blot, and electron microscopy were used to characterize the vascular barrier. Vascular permeability was evaluated by assessing the mucosal expression of plasmalemma vesicle-associated protein-1 and vascular endothelial cadherin. Caco-2 or human umbilical vein endothelial cell monolayers were incubated with soluble mediators released by mucosal biopsies to highlight the mechanisms involved in permeability alteration. Correlation analyses have been performed among experimental and clinical data.

RESULTS

The intestinal epithelial barrier was compromised in patients with IBS throughout the gastrointestinal tract. IBS-soluble mediators increased Caco-2 permeability via a downregulation of tight junction gene expression. Blood vessel density and vascular permeability were increased in the IBS colonic mucosa. IBS mucosal mediators increased permeability in human umbilical vein endothelial cell monolayers through the activation of protease-activated receptor-2 and histone deacetylase 11, resulting in vascular endothelial cadherin downregulation. Permeability changes correlated with intestinal and behavioral symptoms and health-related quality of life of patients with IBS.

CONCLUSIONS

Epithelial and vascular barriers are compromised in patients with IBS and contribute to clinical manifestations.

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.

Adapted Low-FODMAP Diet in IBS Patients with and without Fibromyalgia: Long-Term Adherence and Outcomes

BACKGROUND/OBJECTIVES

A low-FODMAPs Diet (LFD) is considered a "second line" dietary strategy for irritable bowel syndrome (IBS) but, after a period of strict restriction of all FODMAP foods, it has to be adapted and tailored to each patient (AdLFD). Fibromyalgia often coexists with IBS in up to 65% of cases. Our aims were to evaluate if comorbid fibromyalgia influenced the long-term clinical outcomes and adherence to an AdLFD in IBS patients.

METHODS

IBS patients with or without fibromyalgia who had started an AdLFD were enrolled. Patients had been evaluated before starting the LFD (T0). After a mean follow-up of 62.5 ± 22.7 months (T1), they were re-evaluated using questionnaires on disease severity, bowel habits, psychological status, and adherence to AdLFD.

RESULTS

In total, 51 IBS patients entered the study. Nineteen of them had comorbid fibromyalgia. Thirty patients reported a reduction in symptom severity at T1 in comparison with T0. Despite some slight differences in single IBS Symptom Severity Score items, comorbid fibromyalgia did not influence the IBS-SSS total score at T1. Patients with comorbid fibromyalgia showed a higher Hospital Anxiety and Depression Scale (HADS) score at baseline. A total of 44 patients showed good long-term adherence to the AdLFD. All patients improved their HADS score and had long-term adherence to the AdLFD.

CONCLUSIONS

Comorbid fibromyalgia showed only a slight influence on long-term outcomes of an AdLFD on IBS symptoms, without affecting the relief of global symptoms. No influence on long-term adherence to AdLFD was detected. Hence, this approach can be taken into account in fibromyalgia patients for a nonpharmacological management of IBS symptoms. However, multicentric studies on larger samples would be welcome in the future.

[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.

Effect of Lacticaseibacillus rhamnosus IDCC 3201 on irritable bowel syndrome with constipation: a randomized, double-blind, and placebo-controlled trial

Irritable bowel syndrome is a chronic disorder affecting the gastrointestinal tract, negatively impacting patients' quality of life. Here, we aimed to evaluate the effects of Lacticaseibacillus rhamnosus IDCC 3201 (RH 3201) on irritable bowel syndrome with constipation (IBS-C). In this randomised, double-blind, placebo-controlled trial, a total of 30 subjects with IBS-C were randomly assigned (1:1) to receive 8 weeks of probiotics administration or placebo. Concerning bowel activities, both irritant bowel movements and discomfort caused by constipation showed significant improvement with RH 3201 at 8 weeks. Symptoms including severity of abdominal bloating, frequency of abdominal bloating, and satisfaction of bowel habits based on the irritable bowel syndrome-severity scoring system also ameliorated in the probiotic group. Analysis of the fecal microbiome revealed that the abundance of Bacteroides cellulosilyticus and Akkermansia muciniphila was higher during the period of RH 3201 administration compared to the placebo. Untargeted metabolome analysis further suggested a correlation between specific metabolites, such as N-acetylornithine, xanthine, and 3-phenylpropionic acid, and the improvement of clinical symptoms. These results indicate that RH 3201 was effective in ameliorating IBS-C, potentially by enriching beneficial microbes and associated metabolites in the gut environment.

Associations of dietary patterns with risk of gastrointestinal disorders: a prospective cohort study

Gastrointestinal (GI) disorders are highly prevalent and severely diminish life quality. It is yet unknown which dietary pattern is optimal for the prevention of GI disorders. Among 141 450 participants from UK Biobank with a median follow-up of 15 years, we comprehensively assessed 13 dietary patterns in relation to 6 GI disorders. Multivariable Cox proportional hazards models demonstrated that adherence to healthy diets was associated with lower risk of GI disorders, with the strongest associations observed for the Dietary Approaches to Stop Hypertension (DASH) diet (HRQ4 vs. Q1 = 0.85, 95% CI: 0.81, 0.88), the Alternate Mediterranean Diet (AMED) (HRQ4 vs. Q1 = 0.85, 95% CI: 0.81, 0.88), and the Alternate Healthy Eating Index-2010 (AHEI-2010) (HRQ4 vs. Q1 = 0.86, 95% CI: 0.82, 0.89). AHEI-2010 (HRs ranging from 0.76 to 0.90) and DASH (HRs ranging from 0.75 to 0.88) showed inverse associations with every individual GI disorder. Furthermore, comorbidities decreased significantly in number with higher AMED and DASH diet scores (P for trend <0.001). Finally, the associations of AHEI-2010, AMED and DASH with GI disorders diminished most intensely after removing the component of fruits or whole grains. The combined intake of fruits and whole grains was inversely associated with the risk of overall GI disorders (HRT3 vs. T1 = 0.89, 95% CI: 0.86, 0.93). In conclusion, AHEI-2010 and DASH were the most recommended dietary patterns for the prevention of GI disorders. Fruits and whole grains are the most significant contributors to the protective effect.

Tongxieyaofang Decotion Alleviates IBS by Modulating CHRM3 and Gut Barrier

Purpose

Through network pharmacology combined with molecular docking and in vivo validation, the study examines the unexplored molecular mechanisms of Tongxieyaofang (TXYF) in the treatment of irritable bowel syndrome (IBS). In particular, the potential pharmacological mechanism of TXYF alleviating IBS by regulating CHRM3 and intestinal barrier has not been studied.

Patients and Methods

LC-MS technique and TCMSP database were used in combination to identify the potential effective components and target sites of TXYF. Potential targets for IBS were obtained from Genecards and OMIM databases. PPI and cytoHub analysis for targets. Molecular docking was used to validate the binding energy of effective components with related targets and for visualization. GO and KEGG analysis were employed to identify target functions and signaling pathways. In the in vivo validation, wrap restraint stress-induced IBS model was employed to verify the change for cytoHub genes and CHRM3 expression. Furthermore, inflammatory changes of colon were observed by HE staining. The changes of Ach were verified by ELISA. IHC and WB validated CHRM3 and GNAQ/PLC/MLCK channel variations. AB-PAS test and WB test confirmed the protection of TXYF on gut barrier. The NF-κB/MLCK pathway was also verified.

Results

In TXYF decoction, LC-MS identified 559 chemical components, with 23 remaining effective components after screening in TCMSP. KEGG analysis indicated that calcium plays a crucial role in TXYF treated for IBS. Molecular docking validated the binding capacity of the effective components Naringenin and Nobiletin with cytoHub-gene and CHRM3. In vivo validation demonstrated that TXYF inhibits the activation of Ach and CHRM3 in IBS, and inhibits for the GNAQ/PLC/MLCK axis. Additionally, TXYF downregulates TNF-α, MMP9, and NF-κB/MLCK, while modulating goblet cell secretion to protect gut barrier.

Conclusion

TXYF inhibits Ach and CHRM3 expression, regulating the relaxation of intestinal smooth muscle via GNAQ/PLC/MLCK. Additionally, TXYF inhibits NF-κB/MLCK activated and goblet cell secretion to protect gut barrier.

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.

Network pharmacology and experimental validation to explore the mechanism of Changji'an formula against irritable bowel syndrome with predominant diarrhea

Changji'an Formula (CJAF) is a Chinese herbal compound, which is effective against irritable bowel syndrome with predominant diarrhea (IBS-D) in clinic. However, the molecular mechanism has not been well defined. In the current study, the potential targets and signaling pathways of CJAF against IBS-D were predicted using network pharmacology analysis. The pharmacological mechanisms of CJAF against IBS-D and the potential mechanism were validated by using an IBS-D mouse model induced by enema with trinitrobenzene-sulfonic acid (TNBS) plus with restraint stress and further intervened with CJAF. A total of 232 active compounds of CJAF were obtained, a total of 397 potential targets for the active ingredients were retrieved and a total of 219 common targets were obtained as the potential targets of CJAF against IBS-D. GO and KEGG enrichment analyses showed that multiple targets were enriched and could be experimentally validated in a mouse model of IBS-D. The mechanisms were mainly converged on the immune and inflammatory pathways, especially the NF-κB, TNF and IL-17 signaling pathway, which were closely involved in the treatment of CJAF against IBS-D. Animal experiment showed that CJAF alleviated visceral hypersensitivity and diarrhea symptom of IBS-D. CJAF also restored the histological and ultrastructure damage of IBS-D. The result of Western blot showed that CJAF upregulated colonic tight junction proteins of ZO-1, Occludin and Claudin-1. Further results demonstrated that CJAF inhibited the protein expression of NF-κB/NLRP3 inflammasome pathway targets and downregulated proinflammatory mediators of IL-1β, IL-18, TNF-α. In conclusion, CJAF could effectively reduce inflammatory response and alleviate visceral hypersensitivity as well as diarrhea symptom of IBS-D by inhibiting the NF-κB/NLRP3 signaling pathway. This study not only reveals the mechanism of CJAF against IBS-D, but also provides a novel therapeutic strategy for IBS-D.

Rapid biotransformation of STW 5 constituents by human gut microbiome from IBS- and non-IBS donors

STW 5, a blend of nine medicinal plant extracts, exhibits promising efficacy in treating functional gastrointestinal disorders, notably irritable bowel syndrome (IBS). Nonetheless, its effects on the gastrointestinal microbiome and the role of microbiota on the conversion of its constituents are still largely unexplored. This study employed an experimental ex vivo model to investigate STW 5's differential effects on fecal microbial communities and metabolite production in samples from individuals with and without IBS. Using 560 fecal microcosms (IBS patients, n = 6; healthy controls, n = 10), we evaluated the influence of pre-digested STW 5 and controls on microbial and metabolite composition at time points 0, 0.5, 4, and 24 h. Our findings demonstrate the potential of this ex vivo platform to analyze herbal medicine turnover within 4 h with minimal microbiome shifts due to abiotic factors. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products, such as 18β-glycyrrhetinic acid, davidigenin, herniarin, 3-(3-hydroxyphenyl)propanoic acid, and 3-(2-hydroxy-4-methoxyphenyl)propanoic acid occurred. For davidigenin, 3-(3-hydroxyphenyl)propanoic acid and 18β-glycyrrhetinic acid, anti-inflammatory, cytoprotective, or spasmolytic activities have been previously described. Notably, the microbiome-driven metabolic transformation did not induce a global microbiome shift, and the detected metabolites were minimally linked to specific taxa. Observed biotransformations were independent of IBS diagnosis, suggesting potential benefits for IBS patients from biotransformation products of STW 5.

IMPORTANCE

STW 5 is an herbal medicinal product with proven clinical efficacy in the treatment of functional gastrointestinal disorders, like functional dyspepsia and irritable bowel syndrome (IBS). The effects of STW 5 on fecal microbial communities and metabolite production effects have been studied in an experimental model with fecal samples from individuals with and without IBS. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products with reported anti-inflammatory, cytoprotective, or spasmolytic activities was observed, which may be relevant for the pharmacological activity of STW 5.

Review article: A practical approach to persistent gastrointestinal symptoms in inflammatory bowel disease in remission

BACKGROUND

Persistent gastrointestinal symptoms are prevalent in adult patients with inflammatory bowel disease (IBD), even when endoscopic remission is reached. These symptoms can have profound negative effects on the quality of life of affected patients and can be difficult to treat. They may be caused by IBD-related complications or comorbid disorders, but they can also be explained by irritable bowel syndrome (IBS)-like symptoms.

AIMS

To provide a practical step-by-step guide to diagnose and treat persistent gastrointestinal symptoms in patients with IBD in remission via a personalised approach.

METHODS

We scrutinised relevant literature on causes, diagnostics and treatment of persistent gastrointestinal symptoms (abdominal pain or discomfort, bloating, abdominal distension, diarrhoea, constipation and faecal incontinence) in patients with IBD in remission.

RESULTS

A graphical practical guide for several steps in diagnosing, identifying potential triggers and adequate treatment of persistent gastrointestinal symptoms in IBD in remission is provided based on supporting literature. The first part of this review focuses on the diagnostic and treatment approaches for potential IBD-related complications and comorbidities. The second part describes the approach to IBS-like symptoms in IBD in remission.

CONCLUSIONS

Persistent gastrointestinal symptoms in IBD in remission can be traced back to potential pathophysiological mechanisms in individual patients and can be treated adequately. For both IBD-related complications and comorbidities and IBS-like symptoms in IBD in remission, pharmacological, dietary, lifestyle or psychological treatments can be effective. A systematic and personalised approach is required to reduce the burden for patients, healthcare systems, and society.

Efficacy of patient education and duloxetine, alone and in combination, for patients with multisystem functional somatic disorder: Study protocol for the EDULOX trial

BACKGROUND

Multisystem functional somatic disorder is characterized by specific patterns of persistent physical symptoms with a complex biopsychosocial etiology. The disorder can lead to disability and personal suffering. Current treatment options require specialized settings, therefore patients often wait a long time to receive specific treatment. Patient education is considered important in most treatment programs, but has only been investigated sparsely as a stand-alone treatment. Pharmacological treatment is limited to tricyclic antidepressants in low doses with no antidepressant properties. Duloxetine has been found effective in single organ functional disorders. As a treatment for multisystem functional somatic disorder, duloxetine could reduce symptoms and treat comorbid anxiety and depression. It may furthermore enhance the effect of patient education through a hypothesized effect on cognitive functioning. The purpose of the EDULOX trial is to study psycho-EDUcation and duLOXetine alone and in combination.

METHODS

This is a nested study design. The parent trial "EDULOX1" (n = 424) will compare a patient education program with enhanced usual care in an open-labelled, randomized controlled trial. In addition to this, eligible participants will furthermore receive either duloxetine or active placebo in the nested, double-blinded, randomized controlled trial, "EDULOX2" (n = 212). Patient and clinician reported outcomes will be collected through questionnaires.

CONCLUSION

The EDULOX trial may establish evidence for treatments applicable for the majority of patients with multisystem functional somatic disorder. If effective, duloxetine would be a more tolerable pharmacological treatment option that can target comorbid depression and anxiety, and potentially boost the effect of patient education. Trial registration number The study is registered at www.

CLINICALTRIALS

gov (NCT06232473) and the internal list of research projects at the Region of Central Denmark (Case number 1-16-02-305-23). Approval from the Danish Medical Research Ethics Committees (Case number: 2212291) and the Danish Medicines Agency was obtained under EudraCT Number: 2022-002780-30 and Sponsor's Protocol Code Number: 9515.

Gut Microbiota and Gastrointestinal Symptoms in the Global Assessment of Obsessive-Compulsive Disorder: A Narrative Review of Current Evidence and Practical Implications

A growing body of literature suggests a link between bowel syndromes (e.g., irritable bowel syndrome and inflammatory bowel disease), gut microbiome alterations, and psychiatric disorders. This narrative review aims to explore the potential role of the gut microbiome in the pathogenesis and clinical presentation of obsessive-compulsive disorder (OCD) and to explore whether there is sufficient evidence to warrant considering gastrointestinal symptoms and their implication for the gut microbiome during the assessment and treatment of OCD. For this purpose, a PubMed search of studies focusing on OCD, gut microbiota, irritable bowel syndrome, and inflammatory bowel disease was conducted by two independent reviewers. While the current literature on gut microbiome and gastrointestinal issues in OCD remains limited, emerging evidence suggests gut microbiome alterations and high rates of bowel syndromes in this population. These findings emphasize the importance of incorporating comprehensive gastrointestinal assessments into the "global assessment of OCD". Such assessment should encompass various factors, including gastrointestinal physical comorbidities and symptoms, nutritional habits, bowel habits, fluid intake, exercise patterns, and potential microbiome dysfunctions and inflammation. Considering the treatment implications, interventions targeting gut health, such as probiotics and dietary modifications, may hold promise in improving symptoms in OCD patients with comorbid gastrointestinal problems. Further research in this area is warranted to better understand the interplay between gut health and OCD and to explore the effectiveness of targeted interventions in improving clinical outcomes.

Exploration of the mechanism of Traditional Chinese Medicine for anxiety and depression in patients with diarrheal irritable bowel syndrome based on network pharmacology and meta-analysis

Background

The efficacy of Chinese herbal medicine (CHM) in managing irritable bowel syndrome with diarrhea (IBS-D) accompanied by anxiety and depression remains uncertain. Thus, a systematic review was carried out employing meta-analysis and network pharmacology to ascertain the efficacy and underlying mechanisms of CHM therapy.

Methods

By conducting a systematic review, including literature search, screening, and data extraction, we identified 25 randomized controlled trials to assess CHM's effectiveness in treating irritable bowel syndrome alongside anxiety and depression. Network pharmacology was utilized to scrutinize the metabolite utility of CHM in addressing this condition. Potential primary mechanisms were synthesized using information sourced from the PubMed database.

Results

Twenty-five studies, including 2055 patients, were analyzed, revealing significant treatment efficacy for IBS-D in the trial group compared to controls [OR = 4.01, 95% CI (2.99, 5.36), I2 = 0%] Additionally, treatment for depression [SMD = -1.08, 95% CI (-1.30, -0.86), p < 0.00001, I2 = 68%; SDS: SMD = -1.69, 95% CI (-2.48, -0.90), p < 0.0001, I2 = 96%] and anxiety [HAMA: SMD = -1.29, 95% CI (-1.68, -0.91), p < 0.00001, I2 = 89%; SAS: SMD = -1.75, 95% CI (-2.55, -0.95), p < 0.00001, I2 = 96%] significantly improved in the trial group. Furthermore, the trial group exhibited a significantly lower disease relapse rate [OR = 0.30, 95% CI (0.20, 0.44), p < 0.00001, I2 = 0%]. CHM treatment consistently improved IBS severity (IBS-SSS) and symptom scores. Network pharmacology analysis identified key chemical metabolites in traditional Chinese medicine formulations, including Beta-sitosterol, Stigmasterol, Quercetin, Naringenin, Luteolin, Kaempferol, Nobiletin, Wogonin, Formononetin, and Isorhamnetin. Utilizing the STRING database and Cytoscape v3.9.0 software, a protein-protein interaction (PPI) network revealed the top eight key targets: IL-6, TNF, PPARG, PTGS2, ESR1, NOS3, MAPK8, and AKT1, implicated in anti-inflammatory responses, antioxidant stress modulation, and neurotransmitter homeostasis maintenance.

Conclusion

Chinese Herbal Medicine (CHM) offers a promising and safe treatment approach for patients dealing with Diarrheal Irritable Bowel Syndrome (IBS-D) accompanied by anxiety and depression; thus, indicating its potential for practical implementation. The most active metabolites of CHM could simultaneously act on the pathological targets of IBS-D, anxiety, and depression.The diverse scope of CHM's therapeutic role includes various aspects and objectives, underscoring its potential for broad utilization.

Impact of Depression on Irritable Bowel Syndrome (IBS)-Associated Gastrointestinal Symptoms: A Cross-Sectional Study in Makkah City, Saudi Arabia

Background Irritable bowel syndrome (IBS) is a functional gastrointestinal chronic disorder associated with symptoms such as abdominal pain, diarrhea, and constipation. One of the factors that could affect the pathogenesis of IBS is depression, a common psychological disorder that causes social and physical disability and affects productivity. A number of Saudi teachers were found to have depression, which was linked with multiple risk factors including chronic illnesses. However, there is limited data that exhibits the association between IBS and depression, specifically. Therefore, our study aims to determine the impact of depression on IBS-associated gastrointestinal symptoms in Makkah City schools, Saudi Arabia. Methods In this cross-sectional study, we used two validated scales and translated them into Arabic and then we distributed them to our targeted population. Our sample size was determined to be 383 but we succeeded in recruiting 477 participants in our study. Data were statistically analyzed using the statistical software Statistical Package for Social Sciences (SPSS), version 23.0 (IBM Corp., Armonk, NY). Results Generally, participants who demonstrated mild levels of Patient Health Questionnaire-9 (PHQ-9) depression scale corresponded significantly with minimal/mild and moderate levels of Gastrointestinal Symptom Rating Scale-IBS (GSRS-IBS) scores (n = 85 and 76, respectively; p ˂ 0.001), while participants who scored moderately on the PHQ-9 depression scale corresponded significantly with a severe level of GSRS-IBS scores (n = 29; p ˂ 0.001). Conclusion Our study found a significant association between different levels of depression and IBS among participants with a positive history of IBS. Further studies about the prevalence of IBS, depression, and the nature of their relationship are strongly recommended, in addition to the necessity of a suicide risk assessment for those with severe depression.

Factors Associated With the Prevalence of Irritable Bowel Syndrome: The Miyagi Part of the Tohoku Medical Megabank Project Community-based Cohort Study

Background/Aims

The objective of this research is to examine factors related to irritable bowel syndrome (IBS) prevalence in a large population-based study.

Methods

A cross-sectional study was conducted with participants in the Miyagi part of the Tohoku Medical Megabank Project Community-Based cohort study who completed the Rome II Modular Questionnaire. Multivariate odds ratios (ORs) for the presence of IBS and 95% confidence intervals (95% CIs) for the reference group were calculated for each factor. Additionally, a stratified analysis was performed by sex and age group (20-49 years, 50-64 years, and ≥ 65 years).

Results

Among 16 252 participants, 3025 (18.6%) had IBS, comprising 750 men (15.5%) and 2275 women (19.9%). Multivariate ORs for the presence of IBS decreased significantly with each year of age (OR, 0.98; 95% CI, 0.98-0.99). Moreover, compared with the reference group, ORs for the presence of IBS were significantly higher in individuals whose home was partially damaged by the Great East Japan Earthquake, those with < 16 years of education, those who spent less time walking, those with high perceived stress (1.77, 1.57-2.01), those with high psychological distress (1.58, 1.36-1.82), and those with high symptoms of depression (1.76, 1.60-1.94). In stratified analyses, a significant relationship was found between psychological factors and IBS prevalence in all sex and age groups.

Conclusions

This large cross-sectional population-based cohort study identified several factors associated with IBS prevalence. Psychological factors were significantly associated with IBS prevalence across all age groups and sexes.

The Possible Synergistic Pharmacological Effect of an Oral Berberine (BBR) and Curcumin (CUR) Complementary Therapy Alleviates Symptoms of Irritable Bowel Syndrome (IBS): Results from a Real-Life, Routine Clinical Practice Settings-Based Study

Irritable bowel syndrome (IBS) is a prevalent chronic functional gastrointestinal disorder, characterised by recurrent abdominal discomfort and altered bowel movements. IBS cause a significantly negative impact on quality of life (QoL). Growing pharmacological evidence suggests that berberine (BBR) and curcumin (CUR) may mitigate IBS symptoms through multiple complementary synergistic mechanisms, resulting in the attenuation of intestinal inflammation and regulation of bowel motility and gut functions. In the present observational study conducted under real-life routine clinical practice settings, 146 patients diagnosed with IBS were enrolled by general practitioner clinics and pharmacies in Belgium. For the first time, this study assessed the potential synergistic pharmacological effect of a combined oral BBR/CUR supplement (Enterofytol® PLUS, containing 200 mg BBR and 49 mg CUR) (two tablets daily for 2 months), serving as complementary therapy in the management of IBS. Following the 2-month supplementation, significant improvements were observed in the patients' IBS severity index (IBSSI) (47.5%) and all the primary IBS symptoms, such as abdominal discomfort (47.2%), distension (48.0%), intestinal transit (46.8%), and QoL (48.1%) (all p < 0.0001). The improvement in the patients' IBSSI was independent of age, sex, and IBS sub-types. The patients' weekly maximum stool passage frequency decreased significantly (p < 0.0001), and the stool status normalized (p < 0.0001). The patients' need for concomitant conventional IBS treatment decreased notably: antispasmodics by 64.0% and antidiarrhoeals by 64.6%. Minor adverse effects were reported by a small proportion (7.1%) of patients, mostly gastrointestinal. The majority (93.1%) experienced symptom improvement or resolution, with a high satisfaction rate (82.6%) and willingness to continue the supplementation (79.0%). These findings support the potential synergistic pharmacological role of BBR and CUR in IBS, and their co-supplementation may alleviate IBS symptoms and improve QoL.

Efficacy and safety of probiotics in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disease characterized by abdominal pain, distension, and altered bowel habits. Probiotics may alleviate IBS symptoms, but clinical trials remain conflicting.

AIMS

To conduct a systematic review and meta-analysis of clinical trials to evaluate the efficacy and safety of probiotics for IBS patients.

METHODS

We searched relevant trials in PubMed, Web of Science, Embase, Cochrane Library, and Google Scholar from 2000 to June 2023. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated for continuous outcomes. A risk ratio (RR) and a 95% CI were calculated for dichotomous outcomes.

RESULTS

A total of 20 studies involving 3011 patients were obtained. The results demonstrated that probiotics are more effective than placebo in reducing global IBS symptoms improvement rate (RR = 1.401, 95% CI 1.182-1.662, P < 0.001) and quality of life scores (SMD = 0.286, 95% CI = 0.154-0.418, P < 0.001). Subgroup analyses showed that a shorter treatment time (less than eight weeks) could reduce distension scores (SMD = 0.197, 95% CI = 0.038-0.356, P = 0.015). High doses (daily dose of probiotics ≥ 10ˆ10) or multiple strains of probiotics exhibit beneficial effects on abdominal pain (SMD = 0.412, 95% CI = 0.112-0.711, P = 0.007; SMD = 0.590, 95% CI = 0.050-1.129, P = 0.032; respectively). However, there was no significant benefit on global symptom scores (SMD = 0.387, 95% CI 0.122 to 0.653, P = 0.004) with statistically high inter-study heterogeneity (I2 = 91.9%, P < 0.001). Furthermore, there was no significant inter-group difference in terms of adverse events frequency (RR = 0.997, 95% CI 0.845-1.177, P = 0.973).

CONCLUSION

Probiotics are effective and safe for IBS patients. High doses or multiple probiotic strains seem preferable, but definite conclusions are challenging due to the high heterogeneity. Large-scale, well-designed, and rigorous trials are needed to confirm their effectiveness.

Prevalence of irritable bowel syndrome and other functional gastrointestinal disorders in Uruguay

INTRODUCTION AND AIMS

Irritable bowel syndrome (IBS) is one of the most frequent functional gastrointestinal disorders. Prevalence worldwide is estimated at 11%. There is little information on the prevalence of the other functional bowel disorders (FBDs). Our aim was to establish the prevalence of IBS and other FBDs according to the Rome IV criteria, in Uruguay.

MATERIALS AND METHODS

An observational, population-based prevalence study was conducted. Data were collected through an online questionnaire, utilizing the Rome IV criteria.

RESULTS

Of the 1,052 participants (79% women, mean patient age 44 years), 47.2% met the Rome IV diagnostic criteria for at least one of the FBDs analyzed. Functional constipation (FC) was the most frequent, at 18.7% (16.4-21.1), followed by IBS at 17.1% (14.9-19.4) and functional diarrhea (FD) at 15.4% (13.3-17.6). IBS with constipation (IBS-C) was the most frequent IBS subtype (35%) and the IBS with diarrhea (IBS-D) subtype predominated in men. All FBDs were more prevalent in women and youths. Of the survey participants with a FBD, 59% stated that they perceived no worsening of their symptoms related to the COVID-19 pandemic.

CONCLUSIONS

Ours is the first prevalence study on FBDs conducted on the Uruguayan general population. Half of the participants surveyed presented with a FBD analyzed in the study. FC was the most frequent, followed by IBS and FD. The prevalence rate of IBS was the highest, based on the Rome IV diagnostic criteria, and constipation was the most frequent subtype.

Association between irritable bowel syndrome and Parkinson's disease by Cohort study and Mendelian randomization analysis

This study aimed to investigate the association between irritable bowel syndrome (IBS) and Parkinson's disease (PD) utilizing prospective cohort study and Mendelian randomization. The dataset contained a substantial cohort of 426,911 participants from the UK Biobank, discussing the association between IBS and PD with Cox proportional hazards models and case-control analysis while adjusting for covariates such as age, gender, ethnicity and education level. In univariate Cox regression model, the risk of PD was reduced in IBS patients (HR: 0.774, 95%CI: 0.625-0.956, P = 0.017), but the statistical significance diminished in the three models after adjusting for other variables. In a few subgroup analyses, IBS patients are less likely to develop into PD, and patients diagnosed with IBS after 2000 also had a lower risk (HR: 0.633, 95%CI: 0.403-0.994, P = 0.047) of subsequently developing PD. In addition, we matched five healthy control participants based on gender and age at the end of the study for each IBS patient diagnosed during the follow-up period, and logistic regression results (OR:1.239, 95%CI: 0.896-1.680, P = 0.181) showed that IBS was not associated with the risk of PD. Mendelian randomization did not find significant evidence of the causal relationship between IBS and Parkinson's disease (OR: 0.801, 95%CI: 0.570-1.278, P = 0.204). Overall, we suggest that IBS status is not associated with the risk of developing PD, and that these findings provide valuable insights into the clinical management and resource allocation of patients with IBS.

Causal association of gastroesophageal reflux disease on irritable bowel syndrome: a two-sample Mendelian randomization study

Background

Recently, observational studies have reported that gastroesophageal reflux disease (GERD) is commonly associated with irritable bowel syndrome (IBS), but the causal relationship is unclear.

Methods

We conducted a two-sample Mendelian randomization study using summary data from genome-wide association studies (GWASs) to explore a causal relationship between GERD (N cases = 129,080) and IBS (N cases = 4,605) of European ancestry. Furthermore, the inverse-variance weighted (IVW) method and a series of sensitivity analyses were used to assess the accuracy and confidence of our results.

Results

We found a significant association of GERD with IBS (NSNP = 74; OR: 1.375; 95% CI: 1.164-1.624; p < 0.001). Reverse MR analysis showed no evidence of a causal association for IBS with GERD (NSNP = 6; OR: 0.996; 95% CI: 0.960-1.034; p = 0.845).

Conclusion

This study provides evidence that the presence of GERD increases the risk of developing IBS, and it is observed from the reverse MR results that IBS did not increase the risk of GERD.