Evaluation of two laboratory model methods for diarrheal irritable bowel syndrome

Long-term exposure to constant light disrupts intestinal stem cells through sympathoexcitation-induced Wnt5a signaling inhibition

Background

Long-term exposure to constant light is becoming a prevalent lifestyle that is associated with irritable bowel syndrome (IBS), a chronic functional gastrointestinal disorder. Intestinal stem cells (ISCs) are an important population of cells that maintain homeostasis and function of intestinal tissues. The purpose of this study was to identify the effects of long-term constant light exposure on gastrointestinal function and the potential mechanisms of sympathetic activity on ISC.

Methods

Rats housed in a 24 h constant light chamber for 4 weeks were used as the constant light exposure animal model. Hematoxylin-eosin staining and immunohistochemical examination were used to determine the pathological changes of the intestine. Propranolol (ARs inhibitor; 40 mg/kg/day), metoprolol (ADRβ1 inhibitor; 50 mg/kg/day), and Box5 (Wnt5a inhibitor; 2 μg/day) were used to examine the effect of sympathoexcitation and Wnt signaling pathway on constant light-induced gastrointestinal disorders.

Results

We found that 4 weeks of constant light exposure in rats resulted in a decrease in the number of ISC and an increase in sympathetic activity. Intestinal β1-adrenoceptor expression and reactive oxygen species (ROS) were significantly increased, but Wnt5a expression decreased in the continuous light-exposed rats. Similarly, we found that administration of the β1-adrenoceptor antagonist metoprolol for 4 weeks attenuated the effects of continuous light exposure on the intestine, which was rescued by the reintroduction of Wnt5a.

Conclusion

Taken together, these data indicate that sympathoexcitation is critical for disruption of ISC under constant light exposure, suggesting that targeting β1-adrenoceptor/oxidative stress/Wnt5a axis may be a potential strategy for ISC disruption induced by prolonged sustained light exposure, providing a new direction for IBS treatment.

The reality of modeling irritable bowel syndrome: progress and challenges

INTRODUCTION

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that is often therapeutically challenging. While research has advanced our understanding of IBS pathophysiology, developing precise models to predict drug response and treatment outcomes remains a significant hurdle.

AREAS COVERED

This perspective provides an overview of the use of animal models alongside cutting-edge technologies used to bring drugs from bench to bedside.Furthermore, the authors examine the progress and limitations of IBS modeling. The authors further discuss the challenges of traditional animal models and gives a spotlight to the potential of innovative technologies, such as organ-on-chip systems, computational models, and artificial intelligence (AI). These approaches intend to enhance both the understanding and treatment of IBS.

EXPERT OPINION

Although animal models have been central to understanding IBS research, they have limitations. The future of IBS research resides in integrating organ-on-chip systems and utilizing modern technological developments, such as AI. These tools will enable the design of more effective treatment strategies and improve patients' overall well-being. To achieve this, collaboration between experts from various disciplines is essential to improve these models and guarantee their clinical application and reliability.

Tryptophan Attenuates Chronic Restraint Stress-Induced Intestinal Injury Through Modulation of Intestinal Barrier Integrity and Gut Microbiota Homeostasis

Background: Chronic stress is associated with detrimental effects on physical health, such as chronic restraint stress (CRS), which can damage the intestinal tract. Although tryptophan has many benefits in maintaining intestinal health, the underlying mechanism of its protective effects against stress-induced intestinal injury remains unclear. Methods: In this study, we constructed a CRS model by using a behavioral restraint device in which mice were restrained for 6 h per day over 14 days and investigated the effects, as well as the potential mechanism of a high-tryptophan diet (0.4% tryptophan), on CRS-induced intestinal injury using scanning electron microscopy, 16S rRNA sequencing, and LC-MS. Results: A 0.4% tryptophan diet (fed ad libitum for 24 days) attenuated CRS-induced pathologies, including weight loss, elevated corticosterone, intestinal barrier injury, increased permeability, and epithelial apoptosis. Tryptophan modulated the gut microbiota composition in CRS-induced mice, increasing the abundance of Bacteroidota and decreasing the abundance of Firmicutes, as well as enhancing metabolic function through pathways identified by KEGG analysis. Additionally, tryptophan restored the levels of short-chain fatty acids (SCFAs), including acetic, propionic, isobutyric, butyric, and valeric acids. Correlation analyses showed interactions between tryptophan, intestinal permeability, SCFAs, and gut microbiota. Conclusions: Tryptophan supplementation attenuates CRS-induced intestinal injury by modulating intestinal barrier integrity and gut microbiota homeostasis, and the beneficial effects are largely associated with the SCFA-mediated regulation of intestinal permeability and microbiota-associated energy metabolism.

A Bifunctional "Two-in-One" Array for Simultaneous Diagnosis of Irritable Bowel Syndrome and Identification of Low-FODMAP Diets

Irritable bowel syndrome (IBS) is a globally prevalent functional gastrointestinal disorder frequently misdiagnosed due to overlapping symptoms with other diseases. Currently, there are no rapid and effective diagnostic or therapeutic approaches for IBS. Despite this, low-FODMAP diets (LFDs) have become a major dietary intervention strategy for symptom relief. However, detecting FODMAPs usually relies on chromatographic techniques, which are costly and time-consuming, making it difficult to apply in real-time detection. In this study, we introduce the first dual-functional sensor array capable of rapidly diagnosing IBS and identifying low-FODMAP diets. This six-element array was constructed using nitrophenylboronic acid-modified poly(ethylenimine) coupled with coumarins through dynamic borate ester bonds across a range of pH conditions. Optimized by diverse machine learning algorithms, with the multilayer perceptron (MLP) algorithm proving optimal, the array enabled the simultaneous identification of 12 intestinal bacteria with 99.2% accuracy and the detection of mouse fecal specimens with varying degrees of IBS with 99.8% accuracy within seconds. Furthermore, it allowed for the detection of various FODMAP levels in commercially purchased, brand-named, and differently processed soy milk. The array demonstrates potential for use in both the clinical diagnosis of IBS and the guiding of low-FODMAP diets for patients.

Improvement effect and mechanism of XuanFuDaiZhe tang on rats with diarrheal irritable bowel syndrome induced by colorectal dilation

ETHNOPHARMACOLOGICAL RELEVANCE

XuanFuDaiZhe Tang (XFDZT) is used in traditional Chinese medicine (TCM) to treat diarrhoea-predominant irritable bowel syndrome (IBS-D). Our laboratory has demonstrated that XFDZT remarkably improves various gastrointestinal motility disorders in animal models. However, previous studies have only focused on one or several protein targets without systematically investigating dynamic changes and protein interrelations.

AIM OF THE STUDY

To explore the mechanisms underlying the therapeutic action of XFDZT in IBS-D using a network pharmacology approach and in vivo experiments.

MATERIALS AND METHODS

The active compounds of XFDZT were selected from TCM Systems Pharmacology and TCM Integrated databases, and potential targets were identified using the Swiss Target Prediction databases. Targets related to IBS-D were mined from the DisGeNet, Drug Bank, and Therapeutic Target databases. The intersecting protein-protein interactions (PPIs) of the drug-disease crossover genes were analysed, and a central PPI network was constructed using the STRING database and Cytoscape 3.7.2. Following Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, a gene pathway network was constructed to identify key target genes and pathways. Using haematoxylin and eosin staining and western blotting, we validated how XFDZT controls water expression in the body to treat IBS-D infection.

RESULTS

First, the results showed that XFDZT contained 1037 active ingredients and 1458 corresponding targets. After intersecting the 252 IBS targets, 108 targets were identified. The main targets of XFDZT were albumin, aquaporins such as AQP1 and AQP3, calmodulin, and the cellular enzyme CYP2C9. GO and KEGG enrichment predicted that the action pathways were the neuroactive ligand-receptor interaction, calcium signalling pathway, serotonergic synapse signalling pathway, cGMP-PKG signalling pathway, cAMP signalling pathway, and MLCK-MLC signalling pathway. Second, an IBS-D rat model was constructed using colorectal dilation (CRD). CRD can significantly induce IBS-D symptoms such as diarrhoea, abdominal pain, and anxiety and depression-like behaviour in rats. XFDZT (10, 20, and 40 g/kg) administered for 14, 21, and 28 days significantly reversed these changes in IBS-D rats in a time- and dose-dependent manner, suggesting that XFDZT significantly improved IBS-D. Finally, the mechanism by which XFDZT improves IBS-D was explored from the perspective of AQPs, tight junction proteins, and motility-related proteins in colon tissue. Compared with the control group, the protein expression of AQP1, AQP3, and AQP8 in the colon tissue of IBS-D rats was significantly downregulated, whereas the protein expression of AQP7 was significantly upregulated. The expression of tight junction-related proteins claudin-1, occludin, and ZO-1 in colon tissue was significantly downregulated, whereas the expression of motility-related proteins p-MLC, MLC, MLCK, and CaM in colon tissue was significantly upregulated, suggesting that IBS-D rats had AQP disorders, epithelial intercellular connections, and motility in colon tissue. The above changes were significantly reversed by XFDZT administration (5, 10, and 20 g/kg) for 14 days.

CONCLUSION

XFDZT significantly improved diarrhoea, abdominal pain, anxiety, and depression in IBS-D rats, and its mechanism of action may be related to the regulation of AQPs, tight junction proteins, and the MLCK-MLC pathway. This study provided a pharmacological experimental basis for the development of XFDZT as a novel drug for the treatment of IBS-D.

Serum salusin levels in diarrhea- and constipation-predominant irritable bowel syndrome

Objective

Inflammation and immunity play major roles in the etiopathogenesis of functional intestinal disorders. The salusins that were identified in this study are important because of their ease of collection, sensitivity and reliability. For that reason, the aim of this study was to analyze the importance of the levels of salusin in the blood, an inflammation-related parameter, in the diagnosis and prediction of irritable bowel disease.

Methodology

The study participants included 28 diagnosed with constipation-predominant IBS, 29 (34.1%) diagnosed with diarrhea-predominant IBS (D-IBS), and 28 (32.9%) controls. Enzyme-linked immune-sorbent assay (ELISA) method has been used for the measurement of salusin levels.

Results

Participants were 50 (58.8%) female and 35 (41.2%) male. The serum levels of salusin-α were substantially reduced in the diarrhea-predominant IBS group vs controls. There was also no major difference in the levels of salusin between the constipation-predominant-IBS and the diarrhea-predominant IBS group.

Conclusion

A major prognostic relationship was found between the level of salusins and the subgroup of D-IBS. It is well known that salusins have been related to inflammatory processes and oxidative injury in previous studies. The relationship between salusin and gastrointestinal diseases should be further investigated. Low-grade submucosal intestinal inflammation is also associated with irritable bowel syndrome. It is our belief that salusins may be useful in diagnosing, predicting or treating 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.

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.

Inflammatory Prostatitis Plus IBS-D Subtype and Correlation with Immunomodulating Agent Imbalance in Seminal Plasma: Novel Combined Treatment

We recently demonstrated the effectiveness of long-term treatment with rifaximin and the probiotic DSF (De Simone formulation) in improving urogenital and gastrointestinal symptoms in patients with both chronic inflammatory prostatitis (IIIa prostatitis) and diarrhea-predominant irritable bowel syndrome (IBS-D), relative to patients with IBS-D alone. Because the low-grade inflammation of the intestine and prostate may be one of the reasons for co-developing both IIIa prostatitis and IBS-D, we designed the present study to once again evaluate the efficacy of combined rifaximin and DSF treatment in patients affected by IIIa prostatitis plus IBS-D, but we also measured seminal plasma pro-inflammatory (IL-6) and anti-inflammatory (IL-10) cytokines before and after treatment. Methods: We consecutively enrolled 124 patients with IIIa prostatitis and IBS-D (diagnosed using the Rome III criteria). Patients were randomized into two groups: group A (n = 64) was treated with rifaximin (seven days per month for three months) followed by DSF, and group B (n = 60) was treated with a placebo. By the end of the intervention, 68.7% and 62.5% of patients from group A reported improved NIH-CPSI (National Institute of Health's Chronic Prostatitis Symptom Index) and IBS-SSS (Irritable Bowel Syndrome Severity Scoring System) scores, respectively, compared to only 3.3% and 5% of the placebo group. Group A patients also had significantly lower mean seminal plasma levels of IL-6 (11.3 vs. 32.4 pg/mL) and significantly higher mean levels of IL-10 (7.9 vs. 4.4 pg/mL) relative to baseline, whereas the levels of IL-6 and IL-10 did not change in the placebo group. Conclusions: The combined treatment with rifaximin and DSF appears to represent the optimal approach for addressing a syndrome such as irritable bowel syndrome (IBS-D plus), which frequently co-occurs with prostatitis (IIIa prostatitis). This approach is particularly beneficial in cases where the symptoms are not always clearly delineated, the etiology is multifactorial, and the diagnosis is multilevel.

Electroacupuncture at different frequencies improves visceral pain in IBS rats through different pathways

BACKGROUND

The aim of this study was to investigate the frequency dependence of electroacupuncture (EA) in alleviating chronic visceral pain in patients with irritable bowel syndrome (IBS) and the differences in the gut microbiota and metabolites as potential mechanisms to explain frequency dependence.

METHODS

A visceral hyperalgesia model was established by colorectal instillation of 2,4,6-trinitrobenzene sulfonic acid in rats, and EA treatment at 2/10 Hz, 2/50 Hz and 2/100 Hz was applied at ST25. Visceral sensation was quantified by the abdominal withdrawal reflex score and the area under the curve of the rectus abdominis electromyogram in response to colorectal distension. Ultrastructural morphological damage of colonic tissue of the rats was examined by transmission electron microscopy. 16S rRNA gene sequencing and 1H-nuclear magnetic resonance spectroscopy were applied to study the differences in the gut microbiota and to perform metabonomic profiling of the colonic tissue.

KEY RESULTS

EA at ST25 at different frequencies attenuated chronic visceral pain, ultrastructural morphological damage to colonic tissue and disruption of the gut microbiota in IBS rats. The frequency of 2/100 Hz has more regulatory pathways than 2/10 Hz and 2/50 Hz. In addition, IBS rats exhibited colonic metabolic disorders, and pantothenate was significantly upregulated after EA treatment at different frequencies. Very low-density lipoprotein and 2-hydroxybutyrate were significantly increased in the 2/10 Hz group, while low density lipoprotein, very low-density lipoprotein, 2-hydroxybutyrate, methylmalonate and alpha-hydroxyisobutyric acid were significantly increased in the 2/100 Hz group.

CONCLUSIONS AND INFERENCES

EA at ST25 at different frequencies attenuated chronic visceral pain through different gut microbiota and metabolic pathways.

Lipase-copper complex/chitosan microspheres; loaded with attapulgite used for the treatment of E. coli-induced diarrhea

Diarrhea is a globally major problem especially Escherichia coli induced diarrhea becoming fatal nowadays in developing countries. Colon-targeted chitosan microspheres (Ms) comprising of lipase‑zinc and lipase‑copper complexes were prepared, loaded with Attapulgite (Cts-Li-Zn-ATG/Ms and Cts-Li-Cu-ATG/Ms) for the treatment of bacterial diarrhea. Thin layer chromatography (TLC) and Fourier-transform infrared spectroscopy (FTIR) studies were used for confirmation of proposed lipase-metal complexes. Ms showed particle size range 18 ± 0.24 to 23 ± 0.83 μm, zeta potential -13.7 ± 0.71 to -29.3 ± 1.34 mV, PDI 0.5 ± 0.04 to 1.0 ± 0.07 and hemolytic activity was found to be <5 ± 1.25 %. After coating with Eudragit S-100 for colon targeting, in-vitro % drug release of ATG at pH 7.4 was 80 ± 0.21 % for Eud-Cts-Li-Zn-ATG/Ms while it was increased to 83 ± 0.54 % for Eud-Cts-Li-Cu-ATG/Ms within 7 h, respectively. In-vivo anti-diarrheal activity of Eud-Cts-Li-Zn-ATG/Ms and Eud-Cts-Li-Cu-ATG/Ms was performed by oral challenge on albino mice having infectious diarrhea colonized with E. coli. Results revealed significant anti-diarrheal effect of proposed Eud-Cts-Li-Cu-ATG/Ms in terms of weight gain from 24 ± 0.12 g to 26.05 ± 0.31 g, which was 2-fold increase as compared to Eud-Cts-Li-Zn-ATG/Ms. Conclusively, Eud-Cts-Li-Cu-ATG/Ms provides an innovative alternate for the treatment of bacterial diarrhea with additional support of chitosan and lipase for nutritional support and immunity which was compromised in diarrheal patients.

Sinisan Alleviates Stress-Induced Intestinal Dysfunction and Depressive-like Behaviors in Mice with Irritable Bowel Syndrome by Enhancing the Intestinal Barrier and Modulating Central 5-Hydroxytryptamine

Irritable bowel syndrome (IBS) is a common chronic functional bowel disorder and is strongly associated with an increased risk of depression and anxiety. The brain-gut axis plays an important role in the pathophysiologic changes in IBS, yet effective treatments for IBS are still lacking. Sinisan, originating from the Treatise on Typhoid Fever by the medical sage Zhang Zhongjing, is a classic formula in the Eight Methods of Traditional Chinese Medicine (TCM) that focuses on dispersing the liver and regulating the spleen, relieving depression and transmitting evils, and has been widely used in the treatment of liver-depression and spleen-deficiency, diarrhea, and related liver and stomach disorders. However, the therapeutic effect of sinisan in IBS has not been clarified. The aim of this study was to investigate the effects of sinisan on stress-induced intestinal dysfunction and depressive behavior in IBS mice. We established a diarrhea-predominant irritable bowel syndrome (IBS-D) mouse model using a 4% acetic acid enema combined with restraint stress, and analyzed the results using behavioral tests, relevant test kits, hematoxylin-eosin (HE) staining, immunofluorescence (IF), Western blot (WB), and quantitative fluorescence polymerase chain reaction (qRT-PCR). The results showed that sinisan administration significantly alleviated intestinal dysfunction and depressive-like behaviors in IBS-D mice, improved mild colonic inflammation and intestinal mucosal permeability, up-regulated the expression of tight junction proteins ZO-1 and occludin. Sinisan significantly alleviated intestinal dysfunction and depressive-like behaviors in IBS-D mice by decreasing the expression of TNF-α, promoting the expression of tight junction proteins (occludin, ZO-1) expression, and inhibiting the Tlr4/Myd88 signaling pathway, thereby attenuating the inflammatory response, protecting the intestinal barrier, and alleviating symptoms in the IBS-D mouse model. Taken together, sinisan may ameliorate intestinal inflammation and the intestinal barrier by regulating 5-HT expression and the Tlr4/Myd88 pathway, thereby alleviating stress-induced intestinal dysfunction and depressive behaviors in IBS-D mice.

Chang-Kang-Fang alleviates diarrhea predominant irritable bowel syndrome (IBS-D) through inhibiting TLR4/NF-κB/NLRP3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Chang-Kang-Fang (CKF), originated from traditional Chinese medicine (TCM) formulas, has been utilized to treat diarrhea predominant irritable bowel syndrome (IBS-D) based on clinical experience. However, the underlying mechanism of CKF for treating IBS-D remains unclear and need further clarification.

AIM OF THE STUDY

The objective of this present investigation was to validate the efficacy of CKF on IBS-D model rats and to uncover its potential mechanism for the treatment of IBS-D.

MATERIALS AND METHODS

We first established the IBS-D rat model through neonatal maternal separation (NMS) in combination with restraint stress (RS) and the administration of senna decoction via gavage. To confirm the therapeutic effect of CKF on treating IBS-D, abdominal withdrawal reflex (AWR) scores, the quantity of fecal pellets, and the fecal water content (FWC) were measured to evaluate the influence of CKF on visceral hypersensitivity and the severity of diarrhea symptom after the intragastric administration of CKF for 14 days. Subsequently, enzyme linked immunosorbent assay (ELISA) was applied to assess the effect of CKF on neuropeptides substance P (SP) and 5-hydroxytryptamine (5-HT), as well as inflammatory cytokines in serum and in intestinal tissues. Further, colonic pathological changes, the amount of colonic mast cells, and the expression level of occludin in rat colon tissues, were investigated by hematoxylin-eosin (HE) staining, toluidine blue staining, and immunohistochemistry, respectively. To explore the underlying mechanisms, alterations in colonic RNA transcriptomics for the normal, model, and CKF treatment groups were assessed using RNA sequencing (RNA-Seq). Subsequently, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunofluorescence (IF) assays were applied to validate the effect of CKF on predicted pathways in vivo and in vitro. In addition, to elucidate the potential active compounds in CKF, 11 representative components found in CKF were selected, and their anti-inflammation potentials were evaluated using LPS-treated RAW264.7 cell models.

RESULTS

CKF treatment significantly reduced the number of fecal pellets, attenuated visceral hypersensitivity, and decreased 5-HT and SP concentrations in serum and colon tissues, along with a reduction in colonic mast cell counts, correlating with improved symptoms in IBS-D rats. Meanwhile, CKF treatment reduced the colonic inflammatory cell infiltration, lowered the levels of IL-6, TNF-α, and IL-1β in serum and colon tissues, and increased the occludin protein expression in colon tissues to improve inflammatory response and colonic barrier function. RNA-Seq, in conjugation with our previous network pharmacology analysis, indicated that CKF might mitigate the symptoms of IBS-D rats by inhibiting the Toll like receptor 4/Nuclear factor kappa-B/NLR family pyrin domain-containing protein 3 (TLR4/NF-κB/NLRP3) pathway, which was confirmed by WB, IF, and qRT-PCR experiments in vivo and in vitro. Furthermore, coptisine, berberine, hyperoside, epicatechin, and gallic acid present in CKF emerged as potential active components for treating IBS-D, as they demonstrated in vitro anti-inflammatory effects.

CONCLUSION

Our findings demonstrate that CKF effectively improves the symptoms of IBS-D rats, potentially through the inhibition of the TLR4/NF-κB/NLRP3 pathway. Moreover, this study unveils the potential bioactive components in CKF that could be applied in the treatment of IBS-D.

Selenium deficiency induces irritable bowel syndrome: Analysis of UK Biobank data and experimental studies in mice

Irritable bowel syndrome (IBS) patients exhibit significantly lower levels of serum selenium (Se) compared to healthy controls. This study integrates a prospective cohort analysis and animal experiments to investigate Se deficiency as a potential risk factor for IBS. Using data from the UK Biobank, a longitudinal analysis was conducted to explore the associations between dietary Se intake and the risk of incident IBS. In animal study, C57BL/6 mice were fed diets with normal (0.2 ppm) or low (0.02 ppm) Se levels to assess the impacts of Se deficiency on IBS symptoms. Furthermore, we performed 16 S rRNA sequencing, untargeted colonic fecal metabolomics analysis, and colon transcriptome profiling to uncover the regulatory mechanisms underlying Se deficiency-induced IBS. The analysis of UK Biobank data revealed a significant correlation between low dietary Se levels and an increased incidence of IBS. In the experimental study, a low Se diet induced IBS symptoms, evidenced by elevated abdominal withdrawal reflex scores, colon inflammation, and severe pathological damage to the colon. Additionally, the low Se diet caused disturbances in gut microbiota, characterized by an increase in Faecalibaculum and Helicobacter, and a decrease in Bifidobacterium and Akkermansia. Combined colonic fecal metabolomics and colon transcriptome analysis indicated that Se deficiency might trigger IBS through disruptions in pathways related to "bile excretion", "steroid hormone biosynthesis", "arachidonic acid metabolism", and "drug metabolism-cytochrome P450". These findings underscore the significant adverse effects of Se deficiency on IBS and suggest that Se supplementation should be considered for IBS patients.

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.

ZO-1 and IL-1RAP Phosphorylation: Potential Role in Mediated Brain-Gut Axis Dysregulation in Irritable Bowel Syndrome-like Stressed Mice

Background and Objectives: Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder often exacerbated by stress, influencing the brain-gut axis (BGA). BGA dysregulation, disrupted intestinal barrier function, altered visceral sensitivity and immune imbalance defects underlying IBS pathogenesis have been emphasized in recent investigations. Phosphoproteomics reveals unique phosphorylation details resulting from environmental stress. Here, we employ phosphoproteomics to explore the molecular mechanisms underlying IBS-like symptoms, mainly focusing on the role of ZO-1 and IL-1RAP phosphorylation. Materials and Methods: Morris water maze (MWM) was used to evaluate memory function for single prolonged stress (SPS). To assess visceral hypersensitivity of IBS-like symptoms, use the Abdominal withdrawal reflex (AWR). Colonic bead expulsion and defecation were used to determine fecal characteristics of the IBS-like symptoms. Then, we applied a phosphoproteomic approach to BGA research to discover the molecular mechanisms underlying the process of visceral hypersensitivity in IBS-like mice following SPS. ZO-1, p-S179-ZO1, IL-1RAP, p-S566-IL-1RAP and GFAP levels in BGA were measured by western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay to validate phosphorylation quantification. Fluorescein isothiocyanate-dextran 4000 and electron-microscopy were performed to observe the structure and function of the intestinal epithelial barrier. Results: The SPS group showed changes in learning and memory ability. SPS exposure affects visceral hypersensitivity, increased fecal water content, and significant diarrheal symptoms. Phosphoproteomic analysis displayed that p-S179-ZO1 and p-S566-IL-1RAP were significantly differentially expressed following SPS. In addition, p-S179-ZO1 was reduced in mice's DRG, colon, small intestine, spinal and hippocampus and intestinal epithelial permeability was increased. GFAP, IL-1β and p-S566-IL-1RAP were also increased at the same levels in the BGA. And IL-1β showed no significant difference was observed in serum. Our findings reveal substantial alterations in ZO-1 and IL-1RAP phosphorylation, correlating with increased epithelial permeability and immune imbalance. Conclusions: Overall, decreased p-S179-ZO1 and increased p-S566-IL-1RAP on the BGA result in changes to tight junction structure, compromising the structure and function of the intestinal epithelial barrier and exacerbating immune imbalance in IBS-like stressed mice.

Sishen Wan enhances intestinal barrier function via regulating endoplasmic reticulum stress to improve mice with diarrheal irritable bowel syndrome

BACKGROUND

Diarrheal irritable bowel syndrome (IBS-D), characterized primarily by the presence of diarrhea and abdominal pain, is a clinical manifestation resulting from a multitude of causative factors. Furthermore, Sishen Wan (SSW) has demonstrated efficacy in treating IBS-D. Nevertheless, its mechanism of action remains unclear.

METHODS

A model of IBS-D was induced by a diet containing 45 % lactose and chronic unpredictable mild stress. Additionally, the impact of SSW was assessed by measuring body weight, visceral sensitivity, defecation parameters, intestinal transport velocity, intestinal neurotransmitter levels, immunohistochemistry, and transmission electron microscopy analysis. Immunofluorescent staining was used to detect the expression of Mucin 2 (MUC2) and Occludin in the colon. Western blotting was used to detect changes in proteins related to tight junction (TJ), autophagy, and endoplasmic reticulum (ER) stress in the colon. Finally, 16S rRNA amplicon sequencing was used to monitor the alteration of gut microbiota after SSW treatment.

RESULTS

Our study revealed that SSW administration resulted in reduced visceral sensitivity, improved defecation parameters, decreased intestinal transport velocity, and reduced intestinal permeability in IBS-D mice. Furthermore, SSW promotes the secretion of colonic mucus by enhancing autophagy and inhibiting ER stress. SSW treatment caused remodeling of the gut microbiome by increasing the abundance of Blautia, Muribaculum and Ruminococcus torques group.

CONCLUSION

SSW can improve intestinal barrier function by promoting autophagy and inhibiting ER stress, thus exerting a therapeutic effect on IBS-D.

Activation of ASIC3/ERK pathway by paeoniflorin improves intestinal fluid metabolism and visceral sensitivity in slow transit constipated rats

Slow transit constipation (STC) is one of the most common gastrointestinal disorders in children and adults worldwide. Paeoniflorin (PF), a monoterpene glycoside compound extracted from the dried root of Paeonia lactiflora, has been found to alleviate STC, but the mechanisms of its effect remain unclear. The present study aimed to investigate the effects and mechanisms of PF on intestinal fluid metabolism and visceral sensitization in rats with compound diphenoxylate-induced STC. Based on the evaluation of the laxative effect, the abdominal withdrawal reflex test, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry were used to detect the visceral sensitivity, fluid metabolism-related proteins, and acid-sensitive ion channel 3/extracellular signal-regulated kinase (ASIC3/ERK) pathway-related molecules. PF treatment not only attenuated compound diphenoxylate-induced constipation symptoms and colonic pathological damage in rats but also ameliorated colonic fluid metabolic disorders and visceral sensitization abnormalities, as manifested by increased colonic goblet cell counts and mucin2 protein expression, decreased aquaporin3 protein expression, improved abdominal withdrawal reflex scores, reduced visceral pain threshold, upregulated serum 5-hydroxytryptamine, and downregulated vasoactive intestinal peptide levels. Furthermore, PF activated the colonic ASIC3/ERK pathway in STC rats, and ASIC3 inhibition partially counteracted PF's modulatory effects on intestinal fluid and visceral sensation. In conclusion, PF alleviated impaired intestinal fluid metabolism and abnormal visceral sensitization in STC rats and thus relieved their symptoms through activation of the ASIC3/ERK pathway.

L-Theanine alleviates heat stress through modulation of gut microbiota and immunity

BACKGROUND

Heat stress (HS) damages the intestines, disrupting gut microbiota and immune balance. l-Theanine (LTA), found in tea, alleviates oxidative stress and cell apoptosis under HS; however, its effects on gut microbiota and immunity under HS remain unclear. To investigate this, we administered LTA doses of 100, 200, and 400 mg·kg-1 ·d-1 to C57BL/6J mice. On day 44, the model group and LTA intervention group were subjected to continuous 7-day HS treatment for 2 h per day.

RESULTS

The results demonstrated that LTA intervention improved food intake, body weight, and intestinal epithelium, and reduced the water intake of heat-stressed mice. It increased the abundance of Turicibacter, Faecalibaculum, Bifidobacterium, and norank_f_Muribaculaceae, while reducing that of Lachnoclostridium and Desulfovibrio. LTA intervention also increased the concentrations of amino acid and lipid metabolites, regulated macrophage differentiation stimulated by gut microbiota and metabolites, reduced the antigen presentation by macrophages to the specific immune system, promoted B-cell differentiation and sIgA secretion, inhibited pro-inflammatory factors, and enhanced intestinal defense. Mechanistically, LTA downregulated heat shock protein 70 expression and the TLR4/NF-κB/p38 MAPK signaling pathway, restoring gut microbiota and immune balance.

CONCLUSION

We suggest that LTA can alleviate HS by modulating gut microbiota, metabolites, and immunity, indicating its potential as a natural active ingredient for anti-HS food products. © 2023 Society of Chemical Industry.

Phenylketonuria (PKU) Urinary Metabolomic Phenotype Is Defined by Genotype and Metabolite Imbalance: Results in 51 Early Treated Patients Using Ex Vivo 1H-NMR Analysis

Phenylketonuria (PKU) is a rare metabolic disorder caused by mutations in the phenylalanine hydroxylase gene. Depending on the severity of the genetic mutation, medical treatment, and patient dietary management, elevated phenylalanine (Phe) may occur in blood and brain tissues. Research has recently shown that high Phe not only impacts the central nervous system, but also other organ systems (e.g., heart and microbiome). This study used ex vivo proton nuclear magnetic resonance (¹H-NMR) analysis of urine samples from PKU patients (mean 14.9 ± 9.2 years, n = 51) to identify the impact of elevated blood Phe and PKU treatment on metabolic profiles. Our results found that 24 out of 98 urinary metabolites showed a significant difference (p < 0.05) for PKU patients compared to age-matched healthy controls (n = 51) based on an analysis of urinary metabolome. These altered urinary metabolites were related to Phe metabolism, dysbiosis, creatine synthesis or intake, the tricarboxylic acid (TCA) cycle, end products of nicotinamide-adenine dinucleotide degradation, and metabolites associated with a low Phe diet. There was an excellent correlation between the metabolome and genotype of PKU patients and healthy controls of 96.7% in a confusion matrix model. Metabolomic investigations may contribute to a better understanding of PKU pathophysiology.