Neural circuits regulating visceral pain.

Visceral hypersensitivity, a common clinical manifestation of irritable bowel syndrome, may contribute to the development of chronic visceral pain, which is a major challenge for both patients and health providers. Neural circuits in the brain encode, store, and transfer pain information across brain regions. In this review, we focus on the anterior cingulate cortex and paraventricular nucleus of the hypothalamus to highlight the progress in identifying the neural circuits involved in visceral pain. We also discuss several neural circuit mechanisms and emphasize the importance of cross-species, multiangle approaches and the identification of specific neurons in determining the neural circuits that control visceral pain.

Top studies of 2023 relevant to primary care: From the PEER team.

OBJECTIVE: To provide a summary of the noteworthy medical articles published in 2023 that are relevant to family physicians. SELECTING THE EVIDENCE: Articles were chosen and ranked by the PEER (Patients, Experience, Evidence, Research) team, a group of primary care health professionals focused on evidence-based medicine. The selection process involved routine surveillance of tables of contents in high-impact medical journals and continuous monitoring of EvidenceAlerts. Articles were prioritized based on their direct applicability to and potential to influence primary care practice. MAIN MESSAGE: Selected articles addressed various clinical areas of primary care. The topics included a comparison of a treat-to-target approach versus a high-intensity statins prescription for lipid management; semaglutide and its impact on cardiovascular outcomes; respiratory syncytial virus vaccine for older adults; chlorthalidone versus hydrochlorothiazide in preventing cardiovascular events; amitriptyline for irritable bowel syndrome; the role of opioids in acute back pain; safety of oral penicillin challenges in patients allergic to penicillin; spironolactone for facial acne; strategies to reverse frailty in older adults; and identifying the provider of chronic disease management. Two "up and coming" medications are also mentioned: retatrutide for weight loss and fezolinetant for vasomotor symptoms of menopause. CONCLUSION: Research published in 2023 yielded several high-quality articles with topics relevant to primary care, including cardiovascular care, irritable bowel syndrome, care of the elderly, and acne management.

Efficacy of a Low-FODMAP Diet for Coeliac Patients with Persistent IBS-like Symptoms despite a Gluten-Free Diet: A Systematic Review.

Background: Persistent symptoms in coeliac disease (CD) can be due to not only poor gluten-free diet (GFD) adherence and complications of CD, but also functional gastrointestinal disorders such as irritable bowel syndrome (IBS). Although the role of a low fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) diet is well-established in IBS, little data are available on its role in coeliac patients with persistent IBS-like symptoms despite a GFD. Methods: We systematically reviewed the literature in accordance with the PRISMA guidelines for studies evaluating the role of FODMAPs and/or a low-FODMAP diet in coeliac patients with persistent symptoms. PubMed and Embase were searched from inception to 16 January 2024 for eligible full-text papers. The study protocol was registered on Open Science Framework. Results: A total of 239 records were identified, and six papers were included. Of these, four were interventional studies comparing a low-FODMAP GFD to a regular GFD for persistent symptoms in 115 total coeliac patients (two randomized controlled trials and two open-label studies). A low-FODMAP GFD for a minimum of 4 weeks was significantly more effective than a regular GFD in reducing symptoms (p < 0.05 in 3/4 studies). Dietary FODMAP content of a conventional GFD was significantly lower than that of non-coeliac patients on a gluten-containing diet (both p < 0.05), especially regarding high-FODMAP grain products. However, coeliac patients consumed more servings of fruits/vegetables high in FODMAP. No relationship between FODMAP intake and persistence of symptoms was reported. Conclusions: A low-FODMAP diet may be beneficial for uncomplicated celiac patients with persistent IBS-like symptoms despite strict adherence to a GFD.

The Effect of Inflammatory Bowel Disease and Irritable Bowel Syndrome on Pravastatin Oral Bioavailability: In vivo and in silico evaluation using bottom-up wbPBPK modeling.

The common disorders irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) can modify the drugs' pharmacokinetics via their induced pathophysiological changes. This work aimed to investigate the impact of these two diseases on pravastatin oral bioavailability. Rat models for IBS and IBD were used to experimentally test the effects of IBS and IBD on pravastatin pharmacokinetics. Then, the observations made in rats were extrapolated to humans using a mechanistic whole-body physiologically-based pharmacokinetic (wbPBPK) model. The rat in vivo studies done herein showed that IBS and IBD decreased serum albumin (> 11% for both), decreased PRV binding in plasma, and increased pravastatin absolute oral bioavailability (0.17 and 0.53 compared to 0.01) which increased plasma, muscle, and liver exposure. However, the wbPBPK model predicted muscle concentration was much lower than the pravastatin toxicity thresholds for myotoxicity and rhabdomyolysis. Overall, IBS and IBD can significantly increase pravastatin oral bioavailability which can be due to a combination of increased pravastatin intestinal permeability and decreased pravastatin gastric degradation resulting in higher exposure. This is the first study in the literature investigating the effects of IBS and IBD on pravastatin pharmacokinetics. The high interpatient variability in pravastatin concentrations as induced by IBD and IBS can be reduced by oral administration of pravastatin using enteric-coated tablets. Such disease (IBS and IBD)-drug interaction can have more drastic consequences for narrow therapeutic index drugs prone to gastric degradation, especially for drugs with low intestinal permeability.

Key lifestyles and health outcomes across 16 prevalent chronic diseases: A network analysis of an international observational study.

Background: Central and bridge nodes can drive significant overall improvements within their respective networks. We aimed to identify them in 16 prevalent chronic diseases during the coronavirus disease 2019 (COVID-19) pandemic to guide effective intervention strategies and appropriate resource allocation for most significant holistic lifestyle and health improvements. Methods: We surveyed 16 512 adults from July 2020 to August 2021 in 30 territories. Participants self-reported their medical histories and the perceived impact of COVID-19 on 18 lifestyle factors and 13 health outcomes. For each disease subgroup, we generated lifestyle, health outcome, and bridge networks. Variables with the highest centrality indices in each were identified central or bridge. We validated these networks using nonparametric and case-dropping subset bootstrapping and confirmed central and bridge variables' significantly higher indices through a centrality difference test. Findings: Among the 48 networks, 44 were validated (all correlation-stability coefficients >0.25). Six central lifestyle factors were identified: less consumption of snacks (for the chronic disease: anxiety), less sugary drinks (cancer, gastric ulcer, hypertension, insomnia, and pre-diabetes), less smoking tobacco (chronic obstructive pulmonary disease), frequency of exercise (depression and fatty liver disease), duration of exercise (irritable bowel syndrome), and overall amount of exercise (autoimmune disease, diabetes, eczema, heart attack, and high cholesterol). Two central health outcomes emerged: less emotional distress (chronic obstructive pulmonary disease, eczema, fatty liver disease, gastric ulcer, heart attack, high cholesterol, hypertension, insomnia, and pre-diabetes) and quality of life (anxiety, autoimmune disease, cancer, depression, diabetes, and irritable bowel syndrome). Four bridge lifestyles were identified: consumption of fruits and vegetables (diabetes, high cholesterol, hypertension, and insomnia), less duration of sitting (eczema, fatty liver disease, and heart attack), frequency of exercise (autoimmune disease, depression, and heart attack), and overall amount of exercise (anxiety, gastric ulcer, and insomnia). The centrality difference test showed the central and bridge variables had significantly higher centrality indices than others in their networks (P < 0.05). Conclusion: To effectively manage chronic diseases during the COVID-19 pandemic, enhanced interventions and optimised resource allocation toward central lifestyle factors, health outcomes, and bridge lifestyles are paramount. The key variables shared across chronic diseases emphasise the importance of coordinated intervention strategies.

Role of Calprotectin, IL-6, and CRP in Distinguishing Between Inflammatory Bowel Disease and Diarrhea Predominant Irritable Bowel Syndrome.

Background: The early establishment of prophylaxis and immediate administration of anticoagulant therapy upon the diagnosis of venous thromboembolism should be the treatment objectives in these patients. Objective: The study aimed to determine the optimal cut-off point of Calprotectin, IL-6 (interleukin-6), CRP (C reactive protein) to differentiate UC, IBS-D. Methods: A cross-sectional descriptive study of 335 individuals ≥15 years old was performed, including 31 healthy controls, 215 with IBS-D, 71 diagnosed with UC, and 18 diagnosed with CD. Receiver Operating Characteristics (ROC), sensitivity, specificity, and area under curve (AUC) were computed. Results: The results showed that the median value of calprotectin (IQR) in healthy participants was 20.0 (6.0 - 34.0) µg/g; 17,7 (8,7-38,9) µg/g in IBS-D group; 1710.0 (588 - 4260,0) µg/g in UC group; and 560.5 (177.8 - 1210.0) µg/g in CD group. Calprotectin concentration in IBD group including UC and CD was higher than IBS-D with p<0.05. The median value of CRP (range IQR) was 1,3 (0,9 - 2,3) mg/L in IBS-D group; 7.0 (2.4 -16.6) mg/L in UC group; and 10.1 (2.2 - 42.5) mg/L in CD group. CRP concentration in IBD group including UC and CD was higher than IBS-D with p<0.05. The median value of IL-6 (range IQR) was 2.3 (1.6 - 5.7) pg/mL in IBS-D group; 16.8 (9.4 - 47.0) pg/mL in UC group; and 9.4 (7.9 - 11.0) pg/mL in CD group. Calprotectin concentration in IBD group including UC and CD was higher than IBS-D with p<0.05. The optimal cut-off point of calprotectin that differentiated IBS-D from IBD was 110.5 µg/g, with sensitivity and specificity of 93.3% and 91.4%, respectively; of IL-6 was 7.2 pg/mL with sensitivity and specificity of 92.0% and 78.0%, respectively; of CRP of 2.4 mg/L had specific sensitivities of 83.3% and 86.0%, respectively. Conclusion: The Calprotectin immunoassay has the best value in discriminating between IBD and IBS-D.

Integrated Virtual Care for Irritable Bowel Syndrome: A Qualitative Study.

Irritable bowel syndrome (IBS) is a condition that affects approximately one in 10 people in the United States (Defrees & Bailey, 2017). Despite the high prevalence of IBS, the medical community struggles to effectively understand, diagnose, and treat this disorder (Ankersen et al., 2021). In recent years, an increasing number of health-tech companies have emerged to offer integrated treatment of IBS via telemedicine. This pilot study explores the patient experience of virtual, multidisciplinary IBS care through a U.S.-based company, Oshi Health. Semistructured interviews were conducted followed by thematic analysis to identify commonalities between patient experience and perspective (Van Manen, 2014). Overarching themes were identified as follows: loss of the grocer, a broken system, and the power of self-trust. Although several limitations exist, including small sample size, the study offers insight into the experience of telemedicine services for IBS and provides a framework for future research.

Serotonin receptor 2B induces visceral hyperalgesia in rat model and patients with diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Serotonin receptor 2B (5-HT2B receptor) plays a critical role in many chronic pain conditions. The possible involvement of the 5-HT2B receptor in the altered gut sensation of irritable bowel syndrome with diarrhea (IBS-D) was investigated in the present study. AIM: To investigate the possible involvement of 5-HT2B receptor in the altered gut sensation in rat model and patients with IBS-D. METHODS: Rectosigmoid biopsies were collected from 18 patients with IBS-D and 10 patients with irritable bowel syndrome with constipation who fulfilled the Rome IV criteria and 15 healthy controls. The expression level of the 5-HT2B receptor in colon tissue was measured using an enzyme-linked immunosorbent assay and correlated with abdominal pain scores. The IBS-D rat model was induced by intracolonic instillation of acetic acid and wrap restraint. Alterations in visceral sensitivity and 5-HT2B receptor and transient receptor potential vanilloid type 1 (TRPV1) expression were examined following 5-HT2B receptor antagonist administration. Changes in visceral sensitivity after administration of the TRPV1 antagonist were recorded. RESULTS: Here, we observed greater expression of the 5-HT2B receptor in the colonic mucosa of patients with IBS-D than in that of controls, which was correlated with abdominal pain scores. Intracolonic instillation of acetic acid and wrap restraint induced obvious chronic visceral hypersensitivity and increased fecal weight and fecal water content. Exogenous 5-HT2B receptor agonist administration increased visceral hypersensitivity, which was alleviated by successive administration of a TRPV1 antagonist. IBS-D rats receiving the 5-HT2B receptor antagonist exhibited inhibited visceral hyperalgesia.Moreover, the percentage of 5-HT2B receptor-immunoreactive (IR) cells surrounded by TRPV1-positive cells (5-HT2B receptor I+) and total 5-HT2B receptor IR cells (5-HT2B receptor IT) in IBS-D rats was significantly reduced by the administration of a 5-HT2B receptor antagonist. CONCLUSION: Our finding that increased expression of the 5-HT2B receptor contributes to visceral hyperalgesia by inducing TRPV1 expression in IBS-D patients provides important insights into the potential mechanisms underlying IBS-D-associated visceral hyperalgesia.

Causality of genetically determined blood metabolites on irritable bowel syndrome: A Mendelian randomization study.

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most common functional bowel disorders and dysmetabolism plays an important role in the pathogenesis of disease. Nevertheless, there remains a lack of information regarding the causal relationship between circulating metabolites and IBS. A two-sample Mendelian randomization (MR) analysis was conducted in order to evaluate the causal relationship between genetically proxied 486 blood metabolites and IBS. METHODS: A two-sample MR analysis was implemented to assess the causality of blood metabolites on IBS. The study utilized a genome-wide association study (GWAS) to examine 486 metabolites as the exposure variable while employing a GWAS study with 486,601 individuals of European descent as the outcome variable. The inverse-variance weighted (IVW) method was used to estimate the causal relationship of metabolites on IBS, while several methods were performed to eliminate the pleiotropy and heterogeneity. Another GWAS data was used for replication and meta-analysis. In addition, reverse MR and linkage disequilibrium score regression (LDSC) were employed for additional assessment. Multivariable MR analysis was conducted in order to evaluate the direct impact of metabolites on IBS. RESULTS: Three known and two unknown metabolites were identified as being associated with the development of IBS. Higher levels of butyryl carnitine (OR(95%CI):1.10(1.02-1.18),p = 0.009) and tetradecanedioate (OR(95%CI):1.13(1.04-1.23),p = 0.003)increased susceptibility of IBS and higher levels of stearate(18:0)(OR(95%CI):0.72(0.58-0.89),p = 0.003) decreased susceptibility of IBS. CONCLUSION: The metabolites implicated in the pathogenesis of IBS possess potential as biomarkers and hold promise for elucidating the underlying biological mechanisms of this condition.

Four-year follow-up of psychiatric and psychosomatic profile in patients with Inflammatory Bowel Disease (IBD).

Psychological characterization of patients affected by Inflammatory Bowel Disease (IBD) focuses on comorbidity with psychiatric disorders, somatization or alexithymia. Whereas IBD patients had higher risk of stable anxiety and depression for many years after the diagnosis of the disease, there is a lack of studies reporting a comprehensive psychosomatic assessment addressing factors of disease vulnerability, also in the long-term. The objective of this investigation is to fill this gap in the current literature. The aims were thus to assess: a) changes between baseline and a 4-year follow-up in psychiatric diagnoses (SCID), psychosomatic syndromes (DCPR), psychological well-being (PWB-I), lifestyle, gastrointestinal symptoms related to IBD and Irritable Bowel Syndrome (IBS)-like symptoms b) stability of psychiatric and psychosomatic syndromes at 4-year follow-up. A total of 111 IBD outpatients were enrolled; 59.5% of them participated at the follow-up. A comprehensive assessment, including both interviews and self-report questionnaires, was provided at baseline and follow-up. Results showed increased psychiatric diagnoses, physical activity, consumption of vegetables and IBS-like symptoms at follow-up. Additionally, whereas psychiatric diagnoses were no longer present and new psychopathological pictures ensued at follow-up, more than half of the sample maintained psychosomatic syndromes (particularly allostatic overload, type A behavior, demoralization) from baseline to follow-up. Long-term presence/persistence of such psychosocial burden indicates the need for integrating a comprehensive psychosomatic evaluation beyond traditional psychiatric nosography in IBD patients. Moreover, since psychosomatic syndromes represent vulnerability factors of diseases, further studies should target subgroups of patients presenting with persistent psychosomatic syndromes and worse course of the disease.

Efficacy of Shu-yi-ning-chang decoction on IBS-D: Modulating Nr4a3 pathway to reduce visceral hypersensitivity.

AIM OF THE STUDY: To evaluate the therapeutic effect of SYNC in diarrhea irritable bowel syndrome (IBS-D) and explore its underlying mechanism through transcriptomic sequencing (RNA-Seq). MATERIALS AND METHODS: A rat model of IBS-D was constructed to elucidate the effects of SYNC. Abdominal withdrawal reflex (AWR), fecal water content (FWC), and recording body weight were calculated to assess visceral sensitivity in rats. Histopathological changes in the colon and alterations in mast cell (MC) count were determined. Immunohistochemistry was employed to assess mast cell tryptase (MCT) expression in rat colons. Serum levels of corticotropin-releasing Hormone (CRH), interleukin-6 (IL-6), calcitonin gene-related peptide (CGRP), and 5-hydroxytryptamine (5-HT) were quantified using ELISA. RNA-Seq of colon tissue was performed, followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Western blot analysis was conducted to quantify the expression levels of key proteins in the Nr4a3 pathway in the colon and hypothalamus tissues of rats. RESULTS: SYNC alleviated visceral hypersensitivity and mood disorders in rats with IBS-D. Moreover, it was positively correlated with its dosage and the observed effects, such as the enhancement of the colon's mucosal lining condition and reduction in the number and activation of MCs within the model group. SYNC reduced the expression levels of factors related to the brain-gut axis and inflammatory markers in the bloodstream. RNA-Seq analysis indicated that SYNC down-regulated the expression of Nr4a3 and PI3K. These SYNC-targeted genes primarily played roles in immune regulation and inflammatory responses, correlating with the modulation of Nr4a3 and the PI3K/AKT pathway. Western blot analysis further confirmed SYNC's influence on inflammation-related MC activation by downregulating key proteins in the Nr4a3/PI3K pathway. CONCLUSIONS: SYNC inhibited mast cell activation and attenuated visceral hypersensitivity in the colon tissues of IBS-D rats. These effects were mediated by the Nr4a3/PI3K signaling pathway.

A randomized double-blind, placebo-controlled trial to evaluate the safety and efficacy of live Bifidobacterium longum CECT 7347 (ES1) and heat-treated Bifidobacterium longum CECT 7347 (HT-ES1) in participants with diarrhea-predominant irritable bowel syndrome.

To determine the efficacy of the probiotic Bifidobacterium longum CECT 7347 (ES1) and postbiotic heat-treated Bifidobacterium longum CECT 7347 (HT-ES1) in improving symptom severity in adults with diarrhea-predominant irritable bowel syndrome (IBS-D), a randomised, double-blind, placebo-controlled trial with 200 participants split into three groups was carried out. Two capsules of either ES1, HT-ES1 or placebo were administered orally, once daily, for 84 days (12 weeks). The primary outcome was change in total IBS-Symptom Severity Scale (IBS-SSS) score from baseline, compared to placebo. Secondary outcome measures were stool consistency, quality of life, abdominal pain severity and anxiety scores. Safety parameters and adverse events were also monitored. The change in IBS-SSS scores from baseline compared to placebo, reached significance in the ES1 and HT-ES1 group, on Days 28, 56 and 84. The decrease in mean IBS-SSS score from baseline to Day 84 was: ES1 (-173.70 [±75.60]) vs placebo (-60.44 [±65.5]) (p < .0001) and HT-ES1 (-177.60 [±79.32]) vs placebo (-60.44 [±65.5]) (p < .0001). Secondary outcomes included changes in IBS-QoL, APS-NRS, stool consistency and STAI-S and STAI-T scores, with changes from baseline to Day 84 being significant in ES1 and HT-ES1 groups, compared to the placebo group. Both ES1 and HT-ES1 were effective in reducing IBS-D symptom severity, as evaluated by measures such as IBS-SSS, IBS-QoL, APS-NRS, stool consistency, and STAI, in comparison to the placebo. These results are both statistically significant and clinically meaningful, representing, to the best of the authors' knowledge, the first positive results observed for either a probiotic or postbiotic from the same strain, in this particular population.

What is already known on this topicIBS is a chronic functional gastrointestinal disorder characterized by abdominal pain, bloating and abnormalities in stool frequency or form. The gut microbiota of people living with IBS differs markedly to the microbiota of healthy individuals. Gut microbiota may play a key role in IBS aetiology and IBS symptoms may be alleviated by modulating the gut microbiota. Several proposed ways to modulate gut health include normalizing the gut microbiota, preventing the overgrowth of pathogenic bacteria, modulating visceral afferent pathways, and enhancing intestinal barrier function. However, significant heterogeneity between studies, study quality and population, study design and concerns about sample size have limited national and supranational bodies from recommending probiotics for IBS. Further well-powered, randomized, repeatable and controlled trials are warranted.What this study addsThe results of this study substantially contribute to the IBS research field, firstly by providing clinically meaningful and statistically significant results from a rigorous, well designed randomized, placebo-controlled trial and secondly, by exploring the use of postbiotics in IBS, an area of research still in its infancy. Probiotic (ES1) and postbiotic (HT-ES1) supplementation significantly reduced IBS symptom severity scores compared to placebo. This study met primary and secondary outcomes and strongly suggest that ES1 and HT-ES1 could be beneficial in the management of IBS.How this study might affect research, practice, or policyThis study adds to the current evidence base, supporting the use of probiotic/postbiotics for IBS. This research could be used to inform health professionals about using probiotics in IBS and help improve the quality of life and wellbeing for people living with the condition.

Development and Validation of a High-Performance Liquid Chromatography Method to Quantify Marker Compounds in Lysimachia vulgaris var. davurica and Its Effects in Diarrhea-Predominant Irritable Bowel Syndrome.

Irritable bowel syndrome (IBS), a common gastrointestinal disorder worldwide, is characterized by chronic abdominal pain, bloating, and disordered defecation. IBS is associated with several factors, including visceral hypersensitivity, gut motility, and gut-brain interaction disorders. Because currently available pharmacological treatments cannot adequately improve symptoms and may cause adverse effects, the use of herbal therapies for managing IBS is increasing. Lysimachia vulgaris var. davurica (LV) is a medicinal plant used in traditional medicine to treat diarrhea. However, information on whether LV can effectively improve diarrhea-predominant IBS (IBS-D) remains limited. In this study, using an experimental mouse model of IBS-D, we elucidated the effects of the LV extract. The methanol extract of LV decreased fecal pellet output in the restraint stress- or 5-hydroxytryptamine (5-HT)-induced IBS mouse model and inhibited 5-HT-mediated [Ca2+]i increase in a dose-dependent manner. Furthermore, we developed and validated a high-performance liquid chromatography method using two marker compounds, namely, chlorogenic acid and rutin, for quality control analysis. Our study results suggest the feasibility of the methanol extract of LV for developing therapeutic agents to treat IBS-D by acting as a 5-HT3 receptor antagonist.

Prolonged Intake of Luvos Healing Earth does not alter the Composition of the Gut Microbiota in Patients with Diarrhea-predominant Irritable Bowel Syndrome and Healthy Controls.

BACKGROUND AND AIMS: The mineral compound Luvos Healing Earth (LHE) is a commercially available remedy empirically used for a variety of gastrointestinal disorders. The aim of this study was to investigate the possible effect of prolonged LHE therapy on gut microbiota in healthy individuals and in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). METHODS: In this prospective exploratory study, a total of 20 participants, including 12 healthy controls and 8 patients with IBS-D, received treatment with LHE (Magenfein Granulat, 1 sachet bid) for 6 weeks. Fecal samples were collected for microbiota analysis in the morning fasting state at regular intervals at 6 different timepoints: 2 weeks before starting therapy (Screen), and every 2 weeks during LHE therapy (V0-V3). Additionally, a follow-up visit was scheduled 4 weeks after the end of treatment (V4). Microbiota analysis was performed using the GA-map® Dysbiosis Test Lx v2. Dysbiosis Index, bacterial diversity, as well as the balance or imbalance of functionally important bacteria were assessed. RESULTS: The microbiota analysis revealed an overlap in gut microbiota profiles between healthy controls and patients with IBS-D. Bacterial communities were consistently stable during the entire treatment period, and no significant variations in composition were observed 4 weeks after the end of the therapeutic intervention. There was a remarkable stability of microbiota profiles over time within each individual and a high inter-individual variation. The majority of fecal samples exhibited profiles, reflecting an eubiotic state, with no significant changes in dysbiosis index, functional bacteria profiles, or bacterial diversity. CONCLUSION: Our findings indicate intraindividual resilience of microbiota consortia during the entire study period. Prolonged intake of LHE does not cause significant alterations in fecal microbiota profiles in healthy controls and patients with IBS-D. Luvos Healing Earth does not affect the stability of gut microbial diversity and bacterial functions.

A multi-omics study reveals the therapeutic effect of Linderae Radix water extract on irritable bowel syndrome (IBS-D).

ETHNOPHARMACOLOGICAL RELEVANCE: Linderae Radix (Lindera aggregata (Sims) Kosterm) is a traditional Chinese medicine known for its capability to regulate qi and relieve pain, particularly in the context of gastrointestinal disorders. AIM OF THE STUDY: While our previous research has demonstrated the efficacy of the Linderae Radix water extract (LRWE) in the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D), the precise mechanisms remain elusive. This study aims to provide a comprehensive understanding of the therapeutic effects of LRWE on IBS-D through multi-omics techniques. MATERIALS AND METHODS: 16 S rRNA gene sequencing combined with LC-MS metabolomics was employed to investigate the effect of LRWE on the gut microbiota and metabolites of IBS-D rats. Spearman correlation analysis was performed on the gut microbiota and metabolites. RESULTS: LRWE administration significantly ameliorated IBS-D rats' symptoms, including diarrhea, visceral hypersensitivity, and low-grade intestinal inflammation. Gut microbiota analysis revealed that LRWE influenced the diversity of the gut microbiota in IBS-D rats by significantly reducing the relative abundance of Patescibacteria and Candidatus Saccharimonas, while increasing the relative abundance of Jeotgalicoccus. Serum metabolomic analysis identified 16 differential metabolites, associated with LRWE's positive effects on IBS-D symptoms, focusing on glyoxylate and dicarboxylic acid metabolism, and cysteine and methionine metabolism. Spearman analysis demonstrated a strong correlation between cecal microbiota composition and serum metabolite levels. CONCLUSIONS: This study elucidates that LRWE plays a crucial role in the comprehensive therapeutic approach to IBS-D by restoring the relative abundance of gut microbiota and addressing the disturbed metabolism of endogenous biomarkers. The identified bacteria and metabolites present potential therapeutic targets for IBS-D.