Importance of disrupted intestinal barrier in inflammatory bowel diseases

Tributyltin (TBT) toxicity: Effects on enteric neuronal plasticity and intestinal barrier of rats' duodenum

Tributyltin (TBT) is a biocide used in the formulation of antifouling paints and it is highly harmful. Despite the ban, the compound persists in the environment, contaminating marine foodstuffs and household products. Therefore, considering the route of exposure to the contaminant, the gastrointestinal tract (GIT) acts as an important barrier against harmful substances and is a potential biomarker for understanding the consequences of these agents. This work aimed to evaluate histological and neuronal alterations in the duodenum of male Wistar rats that received 20 ng/g TBT and 600 ng/g via gavage for 30 consecutive days. After the experimental period, the animals were euthanized, and the duodenum was intended for neuronal histochemistry (total and metabolically active populations) and histological routine (morphometry and histopathology). The results showed more severe changes in neuronal density and intestinal morphometry in rats exposed to 20 ng/g, such as total neuronal density decrease and reduction of intestinal layers. In rats exposed to 600 ng/g of TBT, it was possible to observe only an increase in intraepithelial lymphocytes. We conclude that TBT can be more harmful to intestinal homeostasis when consumed in lower concentrations.

Gut Epithelial Barrier Function is Impacted by Hyperglycemia and Secondary Bile Acids in Vitro: Possible Rescuing Effects of Specific Pectins

Gut epithelial barrier disruption is commonly observed in Western diseases like diabetes and inflammatory bowel disease (IBD). Enhanced epithelial permeability triggers inflammatory responses and gut microbiota dysbiosis. Reduced bacterial diversity in IBD affects gut microbiota metabolism, altering microbial products such as secondary bile acids (BAs), which potentially play a role in gut barrier regulation and immunity. Dietary fibers such as pectin may substitute effects of these BAs. The study examines transepithelial electrical resistance of gut epithelial T84 cells and the gene expression of tight junctions after exposure to (un)sulfated secondary BAs. This is compared to the impact of the dietary fiber pectin with different degrees of methylation (DM) and blockiness (DB), with disruption induced by calcium ionophore A23187 under both normal and hyperglycemic conditions. Unsulfated lithocholic acid (LCA) and deoxycholic acid (DCA) show a stronger rescuing effect, particularly evident under 20 mM glucose levels. DM19 with high DB (HB) and DM43HB pectin exhibit rescuing effects under both glucose conditions. Notably, DM19HB and DM43HB display higher rescue effects under 20 mM glucose compared to 5 mM glucose. The study demonstrates that specific pectins such as DM19HB and DM43HB may serve as alternatives for preventing barrier disruption in the case of disturbed DCA metabolism.

The gut-brain and gut-macrophage contribution to gastrointestinal dysfunction with systemic inflammation

The gastrointestinal tract is one of the main organs affected during systemic inflammation and disrupted gastrointestinal motility is a major clinical manifestation. Many studies have investigated the involvement of neuroimmune interactions in regulating colonic motility during localized colonic inflammation, i.e., colitis. However, little is known about how the enteric nervous system and intestinal macrophages contribute to dysregulated motility during systemic inflammation. Given that systemic inflammation commonly results from the innate immune response against bacterial infection, we mimicked bacterial infection by administering lipopolysaccharide (LPS) to rats and assessed colonic motility using ex vivo video imaging techniques. We utilized the Cx3cr1-Dtr rat model of transient depletion of macrophages to investigate the role of intestinal macrophages in regulating colonic motility during LPS infection. To investigate the role of inhibitory enteric neurotransmission on colonic motility following LPS, we applied the nitric oxide synthase inhibitor, Nω-nitro-L-arginine (NOLA). Our results confirmed an increase in colonic contraction frequency during LPS-induced systemic inflammation. However, neither the depletion of intestinal macrophages, nor the suppression of inhibitory enteric nervous system activity impacted colonic motility disruption during inflammation. This implies that the interplay between the enteric nervous system and intestinal macrophages is nuanced, and complex, and further investigation is needed to clarify their joint roles in colonic motility.

An investigation into the HIF-dependent intestinal barrier protective mechanism of Qingchang Wenzhong decoction in ulcerative colitis management

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is a chronic, non-specific inflammatory disease affecting the colon and rectum with an etiology that remains elusive. Traditional Chinese medicine (TCM) has been widely used on long-term UC treatment to better maintain the efficacy than traditional aminosalicylic acid or glucocorticosteroids and to ease financial burden of patients. Qingchang Wenzhong Decoction (QCWZD) is a modern TCM decoction with established clinical efficacy but the mechanism of its protection on intestinal barrier function remains unclear.

AIM OF THE STUDY

Current findings highlight that the activation of the hypoxia inducible factor (HIF) pathway can facilitate the repair of intestinal epithelium barrier. This study is to investigate the protective effects of QCWZD and its HIF-targeted ingredients on hypoxia-dependent intestinal barrier.

METHODS

The mice model of UC was induced by dextran sulfate sodium (DSS). Disease activity index (DAI) and histopathology scores and colon length were used to measure the severity of colitis. The DAO activity in serum and protein expression of tight junction (TJ) proteins were detected to explore the function of intestinal barrier. The protein levels of HIF-1α and its downstream gene heme oxygenase-1 (HO-1) were measured as well. HIF-targeted active ingredients in QCWZD were selected by network pharmacology and molecular docking. Protective effects of six constituents on HIF-related anti-oxidative and barrier protective pathway were evaluated by lipopolysaccharide (LPS)-induced HT29 and RAW264.7 cells, through the measurement of the production of ROS and mRNA level of pro-inflammatory cytokines. HIF-1α knockdown was carried out to explore the correlation of protection effects with HIF-related pathway of the active ingredients.

RESULTS

QCWZD effectively alleviated colitis induced by DSS and demonstrated a protective effect on intestinal barrier function by upregulating HIF-related pathways. Six specific ingredients in QCWZD, targeting HIF, successfully reduced the production of cellular ROS and proinflammatory cytokines in LPS-induced cells. It is noteworthy that the barrier protection provided by these molecules is intricately linked with the HIF-related pathway.

CONCLUSIONS

This study elucidates the HIF-related molecular mechanism of QCWZD in protecting the function of the epithelial barrier. Six compounds targeting the activation of the HIF-dependent pathway were demonstrated to unveil a novel therapeutic approach for managing UC.

Sophoricoside improved Crohn's disease-like colitis by inhibiting intestinal epithelial cell apoptosis through PI3K/AKT signaling

BACKGROUND AND AIMS

Increased apoptosis of intestinal epithelial cells (IECs) is a significant cause of intestinal barrier dysfunction in Crohn's disease (CD). Sophoricoside (SOP) is an isoflavone glycoside known for its anti-apoptotic properties. The aim of this study was to investigate the effects of SOP on mice with CD-like colitis and to understand the underlying mechanisms.

METHODS

Mice treated with 2,4,6-trinitrobenzene sulfonic acid (TNBS) were used to examine the therapeutic effect of SOP on CD-like colitis and intestinal barrier damage. To further explore SOP's impact on IECs apoptosis and intestinal barrier protection, an in vitro colonic organoid apoptosis model induced by TNF-α was utilized. Network pharmacology was employed to predict the relevant pathways and molecular processes associated with SOP in the treatment of CD.

RESULTS

Treatment with SOP significantly improved colitis symptoms in TNBS mice, as demonstrated by reductions in the Disease Activity Index (DAI), weight loss, colon shortening, macroscopic scores, colonic tissue inflammatory scores, and the expression of pro-inflammatory factors. Our experiments confirmed that SOP protects the intestinal barrier by counteracting IECs apoptosis. Additionally, this study established that SOP reduced IECs apoptosis by inhibiting the PI3K/AKT signaling pathway.

CONCLUSIONS

SOP can reduce IECs apoptosis through the inhibition of the PI3K/AKT signaling pathway, thereby protecting the intestinal barrier. This study is the first to illustrate how SOP ameliorates colitis and protects the intestinal barrier, suggesting SOP has potential clinical application in treating CD.

Sex-Specific Effect of Ethanol on Colon Content Lipidome in a Mice Model Using Nontargeted LC/MS

Consumption of alcohol has widespread effects on the human body. The organs that are most significantly impacted are the liver and digestive system. When alcohol is consumed, it is absorbed in the intestines and processed by the liver. However, excessive alcohol use may affect gut epithelial integrity, microbiome composition, and lipid metabolism. Despite past studies investigating the effect of ethanol on hepatic lipid metabolism, the focus on colonic lipid metabolism has not been well explored. In this study, we investigated the sex-specific effect of ethanol on the colonic content lipidome in a mouse model using nontargeted liquid chromatography-mass spectrometry. Comprehensive lipidome analysis of colonic flush samples was performed using ethanol-fed (EF) and pair-fed (PF) mice of each sex. Partial least-squares discriminant analysis revealed that ethanol altered colonic lipid composition largely in male mice compared with female mice. A significant increase in free fatty acids, ceramides, and hexosylceramides and decreased phosphatidylglycerols (PG) was observed in the EF group compared to the PF group in male mice. Phosphatidylethanolamine (PE) levels were increased significantly in the EF group of both sexes compared to the PF group. The volcanic plot shows that PG (O-15:1/15:0) and PE (O-18:2/15:0) are common markers that are increased in both sexes of the EF group. In addition, decreased fatty acid esters of hydroxy fatty acids (FAHFA) were observed specifically in the EF group of female mice. Overall, a significant variation in the mice colonic content lipidome between the EF and PF groups was observed. Target pathways, such as sphingolipid metabolism in males, FAHFA in females, and PE metabolism in both sexes, were suggested. This study provides new insight into the sex-dependent lipid change associated with alcohol-induced gut-microbiota dysfunction and its potential health impacts.

Clostridium butyricum isolated from giant panda can attenuate dextran sodium sulfate-induced colitis in mice

Objective

Probiotics are beneficial to the intestinal barrier, but few studies have investigated probiotics from giant pandas. This study aims to explore the preventive effects of giant panda-derived Clostridium butyricum on dextran sodium sulfate (DSS)-induced colitis in mice.

Methods

Clostridium butyricum was administered to mice 14 days before administering DSS treatment to induce enteritis.

Results

Clostridium butyricum B14 could more effectively prevent colitis in mice than C. butyricum B13. C. butyricum B14 protected the mouse colon by decreasing the histology index and serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels, which improved intestinal inflammation-related symptoms. In addition, the treatment led to the regulation of the expression of Tifa, Igkv12-89, and Nr1d1, which in turn inhibited immune pathways. The expression of Muc4, Lama3, Cldn4, Cldn3, Ocln, Zo1, Zo2, and Snai is related the intestinal mucosal barrier. 16S sequencing shows that the C. butyricum B14 significantly increased the abundance of certain intestinal probiotics. Overall, C. butyricum B14 exerted a preventive effect on colitis in mice by inhibiting immune responses, enhancing the intestinal barrier and increasing the abundance of probiotic species. Thus, C. butyricum B14 administration helps regulate the balance of the intestinal microecology. It can suppress immune pathways and enhance barrier-protective proteins.

The role of the gastrointestinal barrier in obesity-associated systemic inflammation

Systemic inflammation is a key contributor to the onset and progression of several obesity-associated diseases and is thought to predominantly arise from the hyperplasia and hypertrophy of white adipose tissue. However, a growing body of works suggests that early changes in the gastrointestinal (GI) barrier may contribute to both local, within the GI lining, and systemic inflammation in obesity. Intestinal barrier dysfunction is well-characterized in inflammatory GI disorders such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) and is known to contribute to systemic inflammation. Thus, drawing parallels between GI disorders, where intestinal permeability and systemic inflammation are prominent features, and obesity-induced GI manifestations may provide insights into the potential role of the intestinal barrier in systemic inflammation in obesity. This review summarizes the current literature surrounding intestinal barrier dysfunction in obesity and explores the potential role of intestinal hyperpermeability and intestinal barrier dysfunction in the development of systemic inflammation and GI dysfunction in obesity.

Emerging role of exosomes in ulcerative colitis: Targeting NOD-like receptor family pyrin domain containing 3 inflammasome

Ulcerative colitis (UC) is a chronic recurrent inflammatory bowel disease. Despite ongoing advances in our understanding of UC, its pathogenesis is yet unelucidated, underscoring the urgent need for novel treatment strategies for patients with UC. Exosomes are nanoscale membrane particles that mediate intercellular communication by carrying various bioactive molecules, such as proteins, RNAs, DNA, and metabolites. The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a cytosolic tripartite protein complex whose activation induces the maturation and secretion of proinflammatory cytokines interleukin-1β (IL-1β) and IL-18, triggering the inflammatory response to a pathogenic agent or injury. Growing evidence suggests that exosomes are new modulators of the NLRP3 inflammasome, with vital roles in the pathological process of UC. Here, recent evidence is reviewed on the role of exosomes and NLRP3 inflammasome in UC. First, the dual role of exosomes on NLRP3 inflammasome and the effect of NLRP3 inflammasome on exosome secretion are summarized. Finally, an outlook on the directions of exosome-NLRP3 inflammasome crosstalk research in the context of UC is proposed and areas of further research on this topic are highlighted.

Taraxacum coreanum Nakai extract attenuates lipopolysaccharide-induced inflammatory responses and intestinal barrier dysfunction in Caco-2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxacum coreanum Nakai (TC) is a dandelion native to Korea that has long been used as a medicinal herb with antioxidant and anti-inflammatory properties. Intestinal inflammation is closely associated with intestinal epithelial barrier disruption, which leads to the progression of various intestinal diseases.

AIM OF THE STUDY

The aim of this study was to investigate the protective effects of TC extract on inflammatory responses and intestinal barrier dysfunction in lipopolysaccharide (LPS)-stimulated Caco-2 cells.

MATERIALS AND METHODS

The inhibitory effect of TC on nitric oxide (NO) and pro-inflammatory cytokines production were determined by Griess reagent and enzyme-linked immunosorbent assay, respectively. The epithelial permeability was evaluated by transepithelial electrical resistance (TEER) assay, and inflammation- and tight junction (TJ)-related protein expression were analyzed by Western blotting. In addition, the presence of ten active compounds was identified and quantified using UHPLC-ESI-MS and HPLC-DAD analyses.

RESULTS

Treatment with TC significantly reduced NO production and pro-inflammatory cytokines production [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] compared to the group treated with LPS only, particularly at 100 μg/mL. TC significantly decreased monolayer permeability as detected by TEER. In addition, the transmission of fluorescein isothiocyanate-dextran 4 across the barrier was decreased after treatment with TC. Inflammation-related proteins (inducible NO synthase, cyclooxygenase-2, TNF-α, IL-6, and IL-1β) were down-regulated after treatment with TC. In contrast, TC significantly increased the protein levels of the TJ-related protein, claudin-5. Ten phytochemicals (protocatechuic acid, chlorogenic acid, caffeic acid, scopoletin, chicoric acid, hyperoside, nicotiflorin, luteoloside, sophoricoside, and luteolin) were identified by UHPLC-ESI-MS and HPLC-DAD analysis.

CONCLUSION

Our findings suggest that ethanolic extract of TC could attenuate the LPS-induced intestinal barrier dysfunction by increasing the TJ protein and suppressing inflammatory responses.

Anemoside B4 ameliorates dextran sulfate sodium (DSS)-induced colitis through inhibiting NLRP3 inflammasome and modulating gut microbiota

Ulcerative colitis (UC) has been recognized as a chronic and relapsing inflammatory disease of the gastrointestinal tract. Clinically, aminosalicylates, immunosuppressants and biological agents are commonly used to treat UC at different stages of the disease. However, these drugs often have side effects. Here, we investigated the anti-UC activity of Anemoside B4 (AB4) in mice with dextran sulfate sodium (DSS) induced colitis. Colon tissues, serum, and colonic contents were collected for assessment of intestinal barrier function, inflammatory cytokines production and microenvironment of intestinal microbiota. Results showed that AB4 alleviated colon shortening, weight lossing and histopathological damage in DSS-induced mice. In addition, we demonstrated both in vivo and in vitro that AB4 remarkably ameliorated colonic inflammation through suppressing NLRP3 pathway. Moreover, AB4 strengthened the intestinal epithelial barrier by regulating myosin light chain kinase (MLCK)-phosphorylated myosin light chain 2 (pMLC2) signaling pathway. Furthermore, we performed 16 S rRNA gene sequencing and fecal microbiome transplantation (FMT) experiments to demonstrate that AB4 alleviated colitis through regulating dysbiosis of intestinal microbiota. These results revealed that AB4 effectively ameliorate experimental UC mainly through regulating MLCK/pMLC2 pathway, NLRP3 pathway and dysbiosis of microbiota, provided new insights into the development of novel anti-UC drugs.

Microalgae polysaccharides exert antioxidant and anti-inflammatory protective effects on human intestinal epithelial cells in vitro and dextran sodium sulfate-induced mouse colitis in vivo

Microalgae polysaccharides (MAPS) have emerged as novel prebiotics, but their direct effects on intestinal epithelial barrier are largely unknown. Here, MAPS isolated from Chlorella pyrenoidosa, Spirulina platensis, and Synechococcus sp. PCC 7002 were characterized as mainly branched heteropolysaccharides, and were bioavailable to Caco-2 cells based on fluorescein isothiocyanate labeling and flow cytometry analysis. These MAPS were equally effective to scavenge hydroxyl and superoxide radicals in vitro and to attenuate the H2O2-, dextran sodium sulfate-, tumor necrosis factor α-, and interleukin 1β-induced burst of intracellular reactive oxygen species and mitochondrial superoxide radicals, interleukin-8 production, cyclooxygenase-2 and inducible nitric oxide synthase expression, and/or tight junction disruption in polarized Caco-2 cells. MAPS and a positive drug Mesalazine were intragastrically administered to C57BL/6 mice daily for 7 d during and after 4-d dextran sodium sulfate exposure. Clinical signs and colon histopathology revealed equivalent anti-colitis efficacies of MAPS and Mesalazine, and based on biochemical analysis of colonic tight junction proteins, goblet cells, mucin 2 and trefoil factor 3 transcription, and colonic and peripheral pro-inflammatory cytokines, MAPS alleviated dextran sodium sulfate-induced intestinal epithelial barrier dysfunction, and their activities were even superior than Mesalazine. Overall, MAPS confer direct antioxidant and anti-inflammatory protection to intestinal epithelial barrier function.

The Role of Gut Microbiota and Leaky Gut in the Pathogenesis of Food Allergy

Food allergy (FA) is a growing public health concern, with an increasing prevalence in Western countries. Increasing evidence suggests that the balance of human gut microbiota and the integrity of our intestinal barrier may play roles in the development of FA. Environmental factors, including industrialization and consumption of highly processed food, can contribute to altering the gut microbiota and the intestinal barrier, increasing the susceptibility to allergic sensitization. Compositional and functional alterations to the gut microbiome have also been associated with FA. In addition, increased permeability of the gut barrier allows the translocation of allergenic molecules, triggering Th2 immune responses. Preclinical and clinical studies have highlighted the potential of probiotics, prebiotics, and postbiotics in the prevention and treatment of FA through enhancing gut barrier function and promoting the restoration of healthy gut microbiota. Finally, fecal microbiota transplantation (FMT) is now being explored as a promising therapeutic strategy to prevent FA in both experimental and clinical studies. In this review article, we aim to explore the complex interplay between intestinal permeability and gut microbiota in the development of FA, as well as depict potential therapeutic strategies.

Polymersomes for protein drug delivery across intestinal mucosa

The oral administration is the route preferred by patients due to its multiple advantages. In the case of biopharmaceuticals, due to their low stability and absorption in the intestine, these molecules must be administered by injectable routes. To circumvent these problems, several strategies have been studied, among which the use of nanosystems, such as polymersomes, can be highlighted. In this work the potential of poloxamer 401 polymersomes as a system for oral delivery of antibodies was evaluated. IgG-FITC-loaded poloxamer 401 polymerosomes were initially used to assess whether it improves intestinal epithelial permeation in Caco-2 cell monolayers. Subsequently, epithelial/macrophage co-culture model was used to evaluate the ability of poloxamer 401 polymersomes containing adalimumab to reduce proinflammatory cytokine levels. The data showed that polymersome-encapsulated IgG increased the transport across intestinal Caco-2 monolayers 2.7-fold compared to the antibody in solution. Also, when comparing the groups of blank polymersomes with polymersomes containing adalimumab, decreases of 1.5-, 5.5-, and 2.4-fold in TNF-α concentrations were observed for the polymersomes containing 1.5, 3.75, and 15 µg/mL of adalimumab, respectively. This could indicate a possibility for the oral administration of biopharmaceuticals which would revolutionize many conditions that require the systemic administration such as in inflammatory bowel disease.

A foundational approach to culture and analyze malnourished organoids

The gastrointestinal (GI) epithelium plays a major role in nutrient absorption, barrier formation, and innate immunity. The development of organoid-based methodology has significantly impacted the study of the GI epithelium, particularly in the fields of mucosal biology, immunity, and host-microbe interactions. Various effects on the GI epithelium, such as genetics and nutrition, impact patients and alter disease states. Thus, incorporating these effects into organoid-based models will facilitate a better understanding of disease progression and offer opportunities to evaluate therapeutic candidates. One condition that has a significant effect on the GI epithelium is malnutrition, and studying the mechanistic impacts of malnutrition would enhance our understanding of several pathologies. Therefore, the goal of this study was to begin to develop methodology to generate viable malnourished organoids with accessible techniques and resources that can be used for a wide array of mechanistic studies. By selectively limiting distinct macronutrient components of organoid media, we were able to successfully culture and evaluate malnourished organoids. Genetic and protein-based analyses were used to validate the approach and confirm the presence of known biomarkers of malnutrition. Additionally, as proof-of-concept, we utilized malnourished organoid-derived monolayers to evaluate the effect of malnourishment on barrier formation and the ability of the bacterial pathogen Shigella flexneri to infect the GI epithelium. This work serves as the basis for new and exciting techniques to alter the nutritional state of organoids and investigate the related impacts on the GI epithelium.

Super-small zwitterionic micelles enable the improvement of blood-brain barrier crossing for efficient orthotopic glioblastoma combinational therapy

Glioblastoma multiforme (GBM) remains incurable in clinical, nanotechnology-based drug delivery strategies show promising perspective in alleviating GBM, while limited blood-brain-barrier (BBB) permeation, short blood half-live accompanied by the poor tumor accumulation and penetration, significantly restrict the therapeutic outcomes. Herein, a versatile super-small zwitterionic nano-system (MCB(S)) based on carboxybetaine (CB) zwitterion functionalized hyperbranched polycarbonate (HPCB) is developed to overcome the brain delivery challenges. After grafting with amino-functionalized IR780 (free IR780), the ultimate paclitaxel (PTX)-encapsulated micelles (MCB(S)-IR@PTX) are precisely activated by near-infrared (NIR) for accelerated drug release and effective combinational GBM therapy. Importantly, MCB(S)-IR@PTX with the crosslinked structure and CB zwitterion prolongs blood-circulation, and CB-zwitterion further facilitates BBB-traversing through betaine/γ-aminobutyric acid (GABA) transporter-1 (BGT-1) pathway. Combined with the benefit of super small-size, MCB(S)-IR@PTX highly accumulates at tumor sites and penetrates deeply, thus efficiently inhibiting tumor growth and strikingly improving survival time in U87MG orthotopic GBM-bearing mouse model. The ingenious nanoplatform furnishes a versatile strategy for delivering therapeutics into the brain and realizing efficient brain cancer therapy.

Intestinal Barrier and Gut Microbiota in Patients with Overlapping Irritable Bowel Syndrome and Functional Dyspepsia

BACKGROUND

Disturbances in the intestinal barrier and gut dysbiosis have been observed in patients with functional bowel diseases.

AIMS

To investigate the correlation between biomarkers of intestinal barrier disorders at different layers and the severity of symptoms in patients with overlapping diarrhea-predominant irritable bowel syndrome and functional dyspepsia (IDFO), as well as with gut microbiota taxa.

METHODS

This study included 45 patients with IDFO and 16 healthy controls. Endoscopy with biopsy of the duodenum and sigmoid colon (SC) was performed to count intraepithelial lymphocytes (IELs) and mucosal eosinophils (subepithelial layer), assess fatty acid binding protein (FABP; epithelial layer) level, and stain for mucin-2 (MUC-2; pre-epithelial layer). Composition of the gut microbiota was evaluated using 16S rRNA gene sequencing.

RESULTS

Patients with IDFO exhibited an increase in biomarkers of intestinal barrier disorders at all layers studied. IEL count in the duodenum was correlated with the severity of bloating (r = 0.336; p = 0.024) and, in the SC, was correlated with tenesmus severity (r = 0.303; p = 0.042). FABP-1 level in the SC was correlated with the severity of diarrhea (r = 0.577; p = 0.001), and FABP-5 concentration in the SC was correlated with abdominal distension (r = 0.477; p = 0.010). MUC-2 concentration in the duodenum was correlated with the severity of heartburn (r = 0.572; p = 0.025) and burning sensation in the epigastrium (r = 0.518; p = 0.048). All biomarkers of intestinal barrier permeability were correlated with the abundance of some gut microbiota taxa.

CONCLUSION

Patients with IDFO exhibited disrupted intestinal barrier function in all layers, which was associated with clinical symptom severity and changes in the gut microbiota.

Cigarette Smoke Mediates Nasal Epithelial Barrier Dysfunction via TNF-α

BACKGROUND

Extensive data suggest that exposure to cigarette smoke can induce pulmonary epithelial barrier dysfunction. However, the effects of cigarette smoke on the nasal epithelial barrier are still unclear. Here, we investigated the consequence and mechanism of cigarette smoke on the nasal epithelial barrier.

METHODS

Sprague Dawley rats were exposed to cigarette smoke for 3 or 6 months, and changes in inflammatory markers and nasal barrier function were evaluated. Moreover, underlying mechanisms were explored. Finally, normal human bronchial epithelial cells were cultured with or without tumor necrosis factor-alpha (TNF-α) in vitro, and the levels of continuity and tight junction-associated proteins were measured.

RESULTS

In vivo experiments showed that the nasal mucosal barrier function of rats exposed to cigarette smoke was disturbed. Indeed, proteins associated with tight junctions were decreased, and the levels of inflammatory factors, such as IL-8, IL-6, and TNF-α, were dramatically increased in comparison to those of control animals. In vitro, TNF-α was shown to disrupt the continuity of proteins associated with tight junctions and to downregulate the expression of these proteins in bronchial epithelial cells.

CONCLUSIONS

We found that cigarette smoke disrupted the nasal mucosal barrier, and the extent of the damage was correlated with the duration of cigarette smoke exposure. We showed that TNF-α can disrupt the continuity and attenuate the expression of tight junction proteins in human bronchial epithelial cells. Therefore, cigarette smoke may induce nasal epithelial barrier dysfunction through TNF-α.

A new face of old cells: An overview about the role of senescence and telomeres in inflammatory bowel diseases

Cellular senescence is a pivotal factor contributing to aging and the pathophysiology of age-related diseases. Despite the presence of inflammation and abnormal immune system function in both inflammatory bowel diseases (IBD) and senescence, the relationship between the two remains largely unexplored. Therefore, our study aimed to investigate the intricate connection between cellular senescence, telomeres, and IBD. The review highlights the presence of senescence markers, particularly p16 and p21, in IBD patients, suggesting their potential association with disease progression and mucosal inflammation. We emphasize the critical role of macrophages in eliminating senescent cells and how disturbance in effective clearance may contribute to persistent senescence and inflammation in IBD. Additionally, we shed light on the involvement of telomeres in IBD, as their dysfunction impairs enterocyte function and disrupts colonic barrier integrity, potentially exacerbating the pathogenesis of the disease. Targeting senescence and telomere dysfunctions holds promise for the development of innovative therapeutic approaches to mitigate intestinal inflammation and alleviate symptoms in IBD patients. By unraveling the precise role of senescence in IBD, we can pave the way for the discovery of novel therapeutic interventions that effectively address the underlying mechanisms of intestinal inflammation, offering hope for improved management and treatment of IBD patients.

Ag- but Not ZnO-Nanoparticles Disturb the Airway Epithelial Barrier at Subtoxic Concentrations

Inhalation is considered to be the most relevant source of human exposure to nanoparticles (NPs); however, only a few investigations have addressed the influence of exposing the respiratory mucosal barrier to subcytotoxic doses. In the nasal respiratory epithelium, cells of the mucosa represent one of the first contact points of the human organism with airborne NPs. Disruption of the epithelial barrier by harmful materials can lead to inflammation in addition to potential intrinsic toxicity of the particles. The aim of this study was to investigate whether subtoxic concentrations of zinc oxide (ZnO)- and silver (Ag)-NPs have an influence on upper airway barrier integrity. Nasal epithelial cells from 17 donors were cultured at the air-liquid interface and exposed to ZnO- and Ag-NPs. Barrier function, quantified by transepithelial electrical resistance (TEER), decreased after treatment with 10 µg/mL Ag-NPs, but FITC-dextran permeability remained stable and no change in mRNA levels of tight junction proteins and E-cadherin was detected by real-time quantitative PCR (RT-qPCR). The results indicate that subtoxic concentrations of Ag-NPs may already induce damage of the upper airway epithelial barrier in vitro. The lack of similar disruption by ZnO-NPs of similar size suggests a specific effect by Ag-NPs.

Inhibition of IEC-6 Cell Proliferation and the Mechanism of Ulcerative Colitis in C57BL/6 Mice by Dandelion Root Polysaccharides

An exploration was conducted on the potential therapeutic properties of dandelion polysaccharide (DP) in addressing 3% dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in murine models. Subsequent assessments focused on DP's influence on inflammation, oxidative stress, and ferroptosis in IEC-6 cells damaged by H2O2. Results highlighted the efficacy of DP in mitigating weight loss, improving disease activity index scores, normalizing colon length, and alleviating histological abnormalities in the affected mice. DP repaired colonic mitochondrial damage by enhancing iron transport and inhibited iron death in colonic cells. Moreover, DP played a pivotal role in enhancing the antioxidant potential. This was evident from the increased expression levels of Nrf2, HO-1, NQO-1, and GSH, coupled with a decrease in MDA and 4-HNE markers in the UC-afflicted mice. Concurrently, DP manifested inhibitory effects on MPO activation and transcription levels of inflammatory mediators such as IL-1β, IL-6, TNF-α, and iNOS. An upsurge in the expression of occludin and ZO-1 was also observed. Restoration of intestinal tightness resulted in decreased serum LPS and LDH levels. Thereafter, administration of DP by gavage increased fecal flora diversity and relative abundance of probiotics in UC mice. Analysis of metabolites indicated that DP counteracted metabolic disturbances and augmented the levels of short-chain fatty acids in ulcerative colitis-affected mice. In vitro studies underscored the role of DP in triggering Nrf2 activation, which in turn exhibited anti-inflammatory, antioxidant, and anti-ferroptotic properties. Summarily, DP's capacity to activate Nrf2 contributes to the suppression of ferroptotic processes in intestinal epithelial cells of UC-affected mice, enhancing the intestinal barrier's integrity. Beyond that, DP possesses the ability to modulate the gut microbiome, rectify metabolic imbalances, rejuvenate short-chain fatty acid levels, and bolster the intestinal barrier as a therapeutic approach to UC.

Polysaccharide from Smilax glabra Roxb Mitigates Intestinal Mucosal Damage by Therapeutically Restoring the Interactions between Gut Microbiota and Innate Immune Functions

Smilax glabra Roxb (S. glabra) is a conventional Chinese medicine that is mainly used for the reliability of inflammation. However, bioactive polysaccharides from S. glabra (SGPs) have not been thoroughly investigated. Here, we demonstrate for the first time that SGPs preserve the integrity of the gut epithelial layer and protect against intestinal mucosal injury induced by dextran sulfate sodium. Mechanistically, SGPs mitigated colonic mucosal injury by restoring the association between the gut flora and innate immune functions. In particular, SGPs increased the number of goblet cells, reduced the proportion of apoptotic cells, improved the differentiation of gut tight junction proteins, and enhanced mucin production in the gut epithelial layer. Moreover, SGPs endorsed the propagation of probiotic bacteria, including Lachnospiraceae bacterium, which strongly correlated with decreased pro-inflammatory cytokines via the blocking of the TLR-4 NF-κB and MyD88 pathways. Overall, our study establishes a novel use of SGPs for the treatment of inflammatory bowel disease (IBD)-associated mucosal injury and provides a basis for understanding the therapeutic effects of natural polysaccharides from the perspective of symbiotic associations between host innate immune mechanisms and the gut microbiome.

Modulation of intestinal IL-37 expression and its impact on the epithelial innate immune response and barrier integrity

Background and Aims

Intestinal epithelial cells separate the luminal flora from lamina propria immune cells and regulate innate immune responses in the gut. An imbalance of the mucosal immune response and disrupted intestinal barrier integrity contribute to the evolution of inflammatory bowel diseases. Interleukin (IL)-37 has broad anti- inflammatory activity and is expressed by the human intestinal epithelium. Mice ectopically expressing human IL-37 show reduced epithelial damage and inflammation after DSS-induced colitis. Here, we investigated the impact of IL-37 on the innate immune response and tight junction protein expression of mouse intestinal organoids and the modulation of IL37 expression in human intestinal organoids.

Methods

Murine intestinal organoids were generated from IL-37tg and wildtype mice. Human ileal organoids were generated from healthy young donors.

Results

Expression of transgene IL-37 or recombinant IL-37 protein did not significantly reduce overall proinflammatory cytokine mRNA expression in murine intestinal organoids. However, higher IL37 expression correlated with a reduced proinflammatory cytokine response in murine colonic organoids. IL37 mRNA expression in human ileal organoids was modulated by proinflammatory cytokines showing an increased expression upon TNF-α-stimulation and decreased expression upon IFN-gamma stimulation. Transgene IL-37 expression did not rescue TNF-α-induced changes in morphology as well as ZO-1, occludin, claudin-2, and E-cadherin expression patterns of murine jejunal organoids.

Conclusions

We speculate that the anti-inflammatory activity of IL-37 in the intestine is mainly mediated by lamina propria immune cells protecting intestinal epithelial integrity.

1,8-cineole ameliorates colon injury by downregulating macrophage M1 polarization via inhibiting the HSP90-NLRP3-SGT1 complex

Ulcerative colitis (UC) is characterized by chronic relapsing intestinal inflammation. Currently, there is no effective treatment for the disease. According to our preliminary data, 1,8-cineole, which is the main active compound of Amomum compactum Sol. ex Maton volatile oil and an effective drug for the treatment of pneumonia, showed remarkable anti-inflammatory effects on colitis pathogenesis. However, its mechanism of action and direct targets remain unclear. This study investigated the direct targets and mechanism through which 1,8-cineole exerts its anti-inflammatory effects using a dextran sulfate sodium salt-induced colitis mouse model. The effects of 1,8-cineole on macrophage polarization were investigated using activated bone marrow-derived macrophages and RAW264.7 cells. In addition, 1,8-cineole targets were revealed by drug affinity responsive target stability, thermal shift assay, cellular thermal shift assay, and heat shock protein 90 (HSP90) adenosine triphosphatases (ATPase) activity assays. The results showed that 1,8-cineole exhibited powerful anti-inflammatory properties in vitro and in vivo by inhibiting the macrophage M1 polarization and protecting intestinal barrier function. Mechanistically, 1,8-cineole directly interacted with HSP90 and decreased its ATPase activity, also inhibited nucleotide-binding and oligomerization domain-, leucine rich repeat-, and pyrin domain-containing 3 (NLRP3) binding to HSP90 and suppressor of G-two allele of SKP1 (SGT1) and suppressed NLRP3 inflammasome activation in macrophages. These results demonstrated that 1,8-cineole is a potential drug candidate for UC treatment.

Daphnetin attenuates intestinal inflammation, oxidative stress, and apoptosis in ulcerative colitis via inhibiting REG3A-dependent JAK2/STAT3 signaling pathway

Daphnetin is a natural coumarin compound with anti-inflammatory, anti-oxidant, and anti-apoptotic effects, which has been previously demonstrated to ameliorate DSS-induced ulcerative colitis (UC). However, the molecular mechanism involved in the daphnetin-mediated pathological process of UC remains unclarified. The current study used DSS-induced mice and LPS-challenged Caco-2 cells as UC models. Bodyweight, disease activity index (DAI) score, and colon length were used to evaluate the severity of colitis. The histological changes in colon tissues were observed using H&E and PAS staining. Protein levels were detected by western blot. The malondialdehyde (MDA) and superoxide dismutase (SOD) activities were used to assess oxidative stress. Inflammatory responses were evaluated by detecting the levels of inflammatory cytokines (IFN-r, IL-1β, IL-6, and TNF-α) using flow cytometry. CCK-8 and TUNEL assay were employed to determine cell growth and cell death, respectively. The results showed that daphnetin could ameliorate the severity of colitis and attenuate the damage to intestinal structure in DSS-induced mice. Compared with the DSS group, the expression of ZO-1, occludin, and anti-apoptotic protein (BCL-2) was increased while the level of pro-apoptotic proteins (Bax and cleaved caspase 3) was decreased in DSS + daphnetin group. The activity of MDA and SOD, as well as the levels of inflammatory cytokines were substantially suppressed by daphnetin. In consistency, in vitro assays indicated that daphnetin protected Caco-2 cells from LPS-stimulated viability impairment, apoptosis, oxidative stress, and inflammation. Furthermore, daphnetin suppressed the activity of JAK2/STAT signaling in LPS-induced Caco-2 cells in a REG3A-dependent manner. REG3A overexpression abated the ameliorative effects of daphnetin while JAK2/STAT signaling inhibition functioned synergically with daphnetin in LPS-stimulated Caco-2 cells. Collectively, this study deepened the understanding of the therapeutic effects of daphnetin on UC and uncovered for the first time that daphnetin functioned through REG3A-activated JAK2/STAT3 signaling in UC, which may provide novel insights for the treatment of UC.

The gut microbes in inflammatory bowel disease: Future novel target option for pharmacotherapy

Gut microbes constitute the main microbiota in the human body, which can regulate biological processes such as immunity, cell proliferation, and differentiation, hence playing a specific function in intestinal diseases. In recent years, gut microbes have become a research hotspot in the pharmaceutical field. Because of their enormous number, diversity, and functional complexity, gut microbes have essential functions in the development of many digestive diseases. Inflammatory bowel disease (IBD) is a chronic non-specific inflammatory disease with a complex etiology, the exact cause and pathogenesis are unclear. There are no medicines that can cure IBD, and more research on therapeutic drugs is urgently needed. It has been reported that gut microbes play a critical role in pathogenesis, and there is a tight and complex association between gut microbes and IBD. The dysregulation of gut microbes may be a predisposing factor for IBD, and at the same time, IBD may exacerbate gut microbes' disorders, but the mechanism of interaction between the two is still not well defined. The study of the relationship between gut microbes and IBD is not only important to elucidate the pathogenesis but also has a positive effect on the treatment based on the regimen of regulating gut microbes. This review describes the latest research progress on the functions of gut microbes and their relationship with IBD, which can provide reference and assistance for further research. It may provide a theoretical basis for the application of probiotics, fecal microbiota transplantation, and other therapeutic methods to regulate gut microbes in IBD.

Colon-Targeted Release of Turmeric Nonextractable Polyphenols and Their Anticolitis Potential via Gut Microbiota-Dependent Alleviation on Intestinal Barrier Dysfunction in Mice

Solid evidence has emerged supporting the role of nonextractable polyphenols (NEPs) and dietary fibers (DFs) as gut microbiota modulators. This study aims to elucidate gut microbiota-dependent release of turmeric NEPs and examine the possible anti-inflammatory mechanism in the dextran sulfate sodium-induced ulcerative colitis (UC) model. 1.5% DSS drinking water-induced C57BL/6J mice were fed a standard rodent chow supplemented with or without 8% extractable polyphenols (EPs), NEPs, or DFs for 37 days. The bound curcumin, demethoxycurcumin, and bisdemethoxycurcumin in NEPs were released up to 181.5 ± 10.6, 65.2 ± 6.0, and 69.5 ± 7.6 μg/mL by in vitro gut microbiota-simulated fermentation and released into the colon of NEP-supplemented mice by 5.7-, 11.0-, and 7.8-fold higher than pseudo germ-free mice, respectively (p < 0.05). NEPs also enhanced the colonic microbiota-dependent production of short-chain fatty acids in vitro and in vivo (p < 0.05). Interestingly, NEP feeding significantly improved the DSS-caused gut microbiota disorder, epithelial barrier damage, and inflammation of UC mice better than EPs or DFs (p < 0.05). Meanwhile, the pseudo germ-free mice supplemented with NEPs failed to ameliorate UC symptoms. These findings manifest that turmeric NEPs as macromolecular carriers exert the target delivery of polyphenols into the colon for regulating gut microbiota to restore the impaired gut barrier function for alleviation of inflammation.

Intestinal Immune Imbalance is an Alarm in the Development of IBD

Immune regulation plays a crucial role in human health and disease. Inflammatory bowel disease (IBD) is a chronic relapse bowel disease with an increasing incidence worldwide. Clinical treatments for IBD are limited and inefficient. However, the pathogenesis of immune-mediated IBD remains unclear. This review describes the activation of innate and adaptive immune functions by intestinal immune cells to regulate intestinal immune balance and maintain intestinal mucosal integrity. Changes in susceptible genes, autophagy, energy metabolism, and other factors interact in a complex manner with the immune system, eventually leading to intestinal immune imbalance and the onset of IBD. These events indicate that intestinal immune imbalance is an alarm for IBD development, further opening new possibilities for the unprecedented development of immunotherapy for IBD.

Multiomics Strategy Reveals the Mechanism of Action and Ameliorating Effect of Deer Velvet Antler Water Extracts on DSS-Induced Colitis

Velvet antler is a precious traditional Chinese medicine used for thousands of years. This study investigated the anti-colitis effects of water extracts of Formosan sambar deer (SVAE) and red deer (RVAE) to identify the possible mechanisms and the bioactive compounds using a dextran sulfate sodium (DSS)-induced colitis mouse model. The mechanism of action and the ameliorating effects of SVAE and RVAE on DSS-induced colitis were evaluated using a mouse model. Ultra-high performance liquid chromatography-mass/mass and gas chromatography-mass/mass were applied to identify the bioactive components of the SVAE and RVAE water extracts. The results revealed that both high-dose SVAE and RVAE could ameliorate the symptoms of colitis due to reduced systemic inflammatory responses, enhanced intestinal barrier integrity by restoration of tight junction proteins, and improved gut dysbiosis. The potentially bioactive components of SVAE and RVAE were identified as small molecules (<3 kDa). Further identification by untargeted metabolomics analysis suggested that l-carnitine, hypoxanthine, adrenic acid, creatinine, gamma-aminobutyric-lysine, oleic acid, glycine, poly-γ-glutamic acid, and eicosapentaenoic acid in VAWEs might be involved in ameliorating the symptoms of colitis. This study provided evidence for the potential usage of SVAE and RVAE as anti-colitis agents.

A multi-mineral intervention to counter pro-inflammatory activity and to improve the barrier in human colon organoids

Introduction: Ulcerative colitis is a chronic inflammatory condition, and continuous inflammatory stimulus may lead to barrier dysfunction. The goal of this study was to assess barrier proteomic expression by a red algae-derived multi-mineral intervention in the absence or presence of pro-inflammatory insult. Methods: Human colon organoids were maintained in a control culture medium alone or exposed to lipopolysaccharide with a combination of three pro-inflammatory cytokines [tumor necrosis factor-α, interleukin-1β and interferon-γ (LPS-cytokines)] to mimic the environment in the inflamed colon. Untreated organoids and those exposed to LPS-cytokines were concomitantly treated for 14 days with a multi-mineral product (Aquamin®) that has previously been shown to improve barrier structure/function. The colon organoids were subjected to proteomic analysis to obtain a broad view of the protein changes induced by the two interventions alone and in combination. In parallel, confocal fluorescence microscopy, tissue cohesion and transepithelial electrical resistance (TEER) measurements were used to assess barrier structure/function. Results: The LPS-cytokine mix altered the expression of multiple proteins that influence innate immunity and promote inflammation. Several of these were significantly decreased with Aquamin® alone but only a modest decrease in a subset of these proteins was detected by Aquamin® in the presence of LPS-cytokines. Among these, a subset of inflammation-related proteins including fibrinogen-β and -γ chains (FGB and FGG), phospholipase A2 (PLA2G2A) and SPARC was significantly downregulated in the presence of Aquamin® (alone and in combination with LPS-cytokines); another subset of proteins with anti-inflammatory, antioxidant or anti-microbial activity was upregulated by Aquamin® treatment. When provided alone, Aquamin® strongly upregulated proteins that contribute to barrier formation and tissue strength. Concomitant treatment with LPS-cytokines did not inhibit barrier formation in response to Aquamin®. Confocal microscopy also displayed increased expression of desmoglein-2 (DSG2) and cadherin-17 (CDH17) with Aquamin®, either alone or in the presence of the pro-inflammatory stimulus. Increased cohesion and TEER with Aquamin® (alone or in the presence of LPS-cytokines) indicates improved barrier function. Conclusion: Taken together, these findings suggest that multi-mineral intervention (Aquamin®) may provide a novel approach to combating inflammation in the colon by improving barrier structure/function as well as by directly altering the expression of certain pro-inflammatory proteins.

Interaction between mucus layer and gut microbiota in non-alcoholic fatty liver disease: Soil and seeds

ABSTRACT

The intestinal mucus layer is a barrier that separates intestinal contents and epithelial cells, as well as acts as the "mucus layer-soil" for intestinal flora adhesion and colonization. Its structural and functional integrity is crucial to human health. Intestinal mucus is regulated by factors such as diet, living habits, hormones, neurotransmitters, cytokines, and intestinal flora. The mucus layer's thickness, viscosity, porosity, growth rate, and glycosylation status affect the structure of the gut flora colonized on it. The interaction between "mucus layer-soil" and "gut bacteria-seed" is an important factor leading to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Probiotics, prebiotics, fecal microbiota transplantation (FMT), and wash microbial transplantation are efficient methods for managing NAFLD, but their long-term efficacy is poor. FMT is focused on achieving the goal of treating diseases by enhancing the "gut bacteria-seed". However, a lack of effective repair and management of the "mucus layer-soil" may be a reason why "seeds" cannot be well colonized and grow in the host gut, as the thinning and destruction of the "mucus layer-soil" is an early symptom of NAFLD. This review summarizes the existing correlation between intestinal mucus and gut microbiota, as well as the pathogenesis of NAFLD, and proposes a new perspective that "mucus layer-soil" restoration combined with "gut bacteria-seed" FMT may be one of the most effective future strategies for enhancing the long-term efficacy of NAFLD treatment.

Dietary Supplementation of Ancientino Ameliorates Dextran Sodium Sulfate-Induced Colitis by Improving Intestinal Barrier Function and Reducing Inflammation and Oxidative Stress

Ancientino, a complex dietary fiber supplement mimicking the ancient diet, has improved chronic heart failure, kidney function, and constipation. However, its effect on ulcerative colitis is unknown. This study explores the impact of Ancientino on colitis caused by dextran sulfate sodium (DSS) and its mechanisms. Data analyses showed that Ancientino alleviated bodyweight loss, colon shortening and injury, and disease activity index (DAI) score, regulated levels of inflammatory factors (tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), interleukin-1 beta (IL-1β), and interleukin 6 (IL-6)), reduced intestinal permeability (d-lactate and endotoxin), fluorescein isothiocyanate-dextran (FITC-dextran), and diamine oxidase (DAO), repaired colonic function (ZO-1 and occludin), and suppressed oxidative stress (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA)) in vivo and in vitro. In short, this study demonstrated that Ancientino alleviates colitis and exerts an anticolitis effect by reducing inflammatory response, suppressing oxidative stress, and repairing intestinal barrier function. Thus, Ancientino may be an effective therapeutic dietary resource for ulcerative colitis.

Phage-display immunoprecipitation sequencing of the antibody epitope repertoire in inflammatory bowel disease reveals distinct antibody signatures

Inflammatory bowel diseases (IBDs), e.g., Crohn's disease (CD) and ulcerative colitis (UC), are chronic immune-mediated inflammatory diseases. A comprehensive overview of an IBD-specific antibody epitope repertoire is, however, lacking. Using high-throughput phage-display immunoprecipitation sequencing (PhIP-Seq), we identified antibodies against 344,000 antimicrobial, immune, and food antigens in 497 individuals with IBD compared with 1,326 controls. IBD was characterized by 373 differentially abundant antibody responses (202 overrepresented and 171 underrepresented), with 17% shared by both IBDs, 55% unique to CD, and 28% unique to UC. Antibody reactivities against bacterial flagellins dominated in CD and were associated with ileal involvement, fibrostenotic disease, and anti-Saccharomyces cerevisiae antibody positivity, but not with fecal microbiome composition. Antibody epitope repertoires accurately discriminated CD from controls (area under the curve [AUC] = 0.89), and similar discrimination was achieved when using only ten antibodies (AUC = 0.87). Individuals with IBD thus show a distinct antibody repertoire against selected peptides, allowing clinical stratification and discovery of immunological targets.

The role of Nrf2 in the pathogenesis and treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease involving mainly the colorectal mucosa and submucosa, the incidence of which has been on the rise in recent years. Nuclear factor erythroid 2-related factor 2 (Nrf2), known for its key function as a transcription factor, is pivotal in inducing antioxidant stress and regulating inflammatory responses. Numerous investigations have demonstrated the involvement of the Nrf2 pathway in maintaining the development and normal function of the intestine, the development of UC, and UC-related intestinal fibrosis and carcinogenesis; meanwhile, therapeutic agents targeting the Nrf2 pathway have been widely investigated. This paper reviews the research progress of the Nrf2 signaling pathway in UC.

Shikimic Acid Regulates the NF-κB/MAPK Signaling Pathway and Gut Microbiota to Ameliorate DSS-Induced Ulcerative Colitis

Shikimic acid (SA) is a compound extracted from the plant anise and has anti-inflammatory effects. However, any impact on intestinal inflammation or mechanisms involved has not been investigated. The present study used a dextran sulfate sodium (DSS)-induced mouse colitis model to investigate the effects of SA on intestinal inflammation. Intragastric administration of SA slowed DSS-induced weight loss, reduced disease activity index (DAI) score, enhanced the intestinal barrier, reduced the destruction of the colonic structure, inhibited the phosphorylation of key proteins in MAPK and NF-κB signaling pathways, inhibited the expression of inflammatory factors TNF-α, IL-1β, and MPO (P < 0.05), decreased IFN-γ expression (P < 0.05), and increased immunoglobulin IgG content (P < 0.05). After 50 mg/kg SA treatment, the content of Bacteroidetes increased and Proteobacteria decreased in the cecal feces of mice with colitis (P < 0.05) and the richness of gut species increased. In conclusion, SA could improve intestinal inflammation and enhance intestinal immunity, indicating its suitability as a therapeutic candidate.

Intestinal Barrier Function in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. The mechanisms involved in NAFLD onset are complicated and multifactorial. Recent literature has indicated that altered intestinal barrier function is related to the occurrence and progression of liver disease. The intestinal barrier is important for absorbing nutrients and electrolytes and for defending against toxins and antigens in the enteric environment. Major mechanisms by which the intestinal barrier influences the development of NAFLD involve the altered epithelial layer, decreased intracellular junction integrity, and increased intestinal barrier permeability. Increased intestinal permeability leads to luminal dysbiosis and allows the translocation of pathogenic bacteria and metabolites into the liver, inducing inflammation, immune response, and hepatocyte injury in NAFLD. Although research has been directed to NAFLD in recent decades, the pathophysiological changes in NAFLD initiation and progression are still not completely understood, and the therapeutic targets remain limited. A deeper understanding on the correlation between NAFLD pathogenesis and intestinal barrier regulation must be attained. Therefore, in this review, the components of the intestinal barrier and their respective functions and disruptions during the progression of NAFLD are discussed.

IgE-Dependent Food Sensitisation and Its Role in Clinical and Laboratory Presentation of Paediatric Inflammatory Bowel Disease

The rising prevalence of inflammatory bowel disease (IBD) and food allergies and their partially overlapping mechanisms such as microbiome diversity reduction raise questions about the role of allergies in IBD. While data on their comorbidity are available, analysis of IgE-sensitization's influence on the clinical presentation of IBD is lacking and is the aim of this study. Histories of 292 children with newly diagnosed IBD (173 cases of ulcerative colitis, 119 cases of Crohn's disease) were analyzed. Disease age of onset, activity, location, behaviour, and anthropometric and laboratory parameters were tested for its dependence on the presence of chosen IgE sensitization markers. A.o. Chi2, OR and phi coefficient were assessed. In Crohn's disease (CD), elevated total IgE (tIgE) correlated with weight loss, rectal bleeding, ASCA IgG positivity (φ = 0.19 for all) and negatively correlated with complicated disease behaviour (φ = -0.19). TIgE > 5 × reference range correlated with being underweight (φ = 0.2), ASCA IgG positivity (φ = 0.3), ASCA double (IgA and IgG) positivity (φ = 0.25) and elevated total IgG (φ = 0.18). The presence of specific IgEs (sIgE) correlated with extraintestinal manifestations of IBD (φ = 0.19): Egg white sIgE correlated with upper GI involvement (L4b) (φ = 0.26), severe growth impairment (φ = 0.23) and colonic mucosal eosinophilia (φ = 0.19). In ulcerative colitis, decreased IgA correlated with egg white sIgE (φ = 0.3), as well as the presence of any (φ = 0.25) or multiple sIgEs (φ = 0.2); the latter correlated also with elevated IgG (φ = 0.22), fever (φ = 0.18), abdominal pain (φ = 0.16) and being underweight (φ = 0.15). Cow's milk sIgE correlated positively with growth impairment (φ = 0.15) and elevated IgG (φ = 0.17) and negatively with extensive colitis (φ = -0.15). Pancolitis correlated negatively with sIgE presence (φ = -0.15). In summary, single moderate and numerous weak but interesting relationships were observed.

Broccoli seed extract rich in polysaccharides and glucoraphanin ameliorates DSS-induced colitis via intestinal barrier protection and gut microbiota modulation in mice

BACKGROUND

Broccoli has received widespread attention because of its anti-inflammatory and antioxidant effects. The present study aimed to explore the composition of broccoli seed extract (BSE) and its effect on colitis induced by dextran sulfate sodium (DSS).

RESULTS

BSE mainly comprises glucoraphanin and polysaccharides composed of arabinose, galactose, glucose and mannose. Animal experiments suggested that BSE intervention effectively reversed body weight loss, suppressed the levels of proinflammatory interleukin-6, tumor necrosis factor-α and interleukin-1β, and elevated the levels of anti-inflammatory interleukin-10 and the activities of superoxide dismutase and glutathione in DSS-induced colitis mice. According to histopathologic and immunohistochemical analysis of colon tissue, BSE intervention may repair the intestinal barrier by upregulating mRNA levels and the expression of tight junction proteins (claudin-1, occludin and zonula occludens-1). Gas chromatography-mass spectrometry (MS) analysis demonstrated that cecal short-chain fatty acids in mice with BSE administration were significantly increased compared with the model group. Sulforaphane and sulforaphane-N-acetylcysteine were only detected in BSE group mice by ultra-performance liquid chromatography-MS analysis. In addition, BSE intervention evidently increased the abundance of Alistipeds, Coriobacteriaceae UCG-002 and Bifidobacterium and decreased the abundance of Escheichia-Shinella, Lachnospiraceae others, Parabacteroides, Ruminococcaceae others and Turicibacter, which possibly promoted carbohydrate metabolism and short-chain fatty acid production.

CONCLUSION

The present study aimed to elucidate the effect of BSE on colitis and found that BSE, as a novel food ingredient, has great potential for the improvement of colitis. © 2022 Society of Chemical Industry.

Neuroprotection of Food Bioactives in Neurodegenerative Diseases: Role of the Gut Microbiota and Innate Immune Receptors

Gut-brain connections may be mediated by an assortment of microbial molecules, which can subsequently traverse intestinal and blood-brain barriers and impact neurological function. Pattern recognition receptors (PRRs) are important innate immune proteins in the gut. Gut microbiota act in concert with the PRRs is a novel target for regulating host-microbe signaling and immune homeostasis, which may involve the pathogenesis of neurodegenerative diseases. Natural food bioactives bestow a protective advantage on neurodegenerative diseases through immunomodulatory effects of the modified gut microbiota or alterations in the landscape of microbiota-produced metabolites via PRRs modulation. In this review, we discuss the effect of natural food bioactives on the gut microbiota and the role of PRRs in the gut-brain crosstalk. We focused on the neuroprotective mechanisms of natural bioactive compounds behind the action of the gut microbiota and PRRs. Research advances in natural food bioactives as antineurodegeneration agents were also presented.

Polysaccharide from fermented mycelium of Inonotus obliquus attenuates the ulcerative colitis and adjusts the gut microbiota in mice

Ulcerative colitis (UC) is a disease characterized by chronic inflammation of the colon. Polysaccharides not only have biological activities but also can regulate gut microbiota to alleviate the symptoms of UC. In this study, polysaccharide extracted from mycelium of Inonotus obliquus (IOP) was prescribed to treat UC induced by dextran sodium sulfate (DSS) in mice. Compared to model control group (MC), IOP-Low, IOP-Medium and IOP-High (IOP-L, IOP-M and IOP-H) treatment groups increased the body weight rate by 6.0%-9.6%, colon length by 8.57%-25.14% and superoxide dismutase (SOD) activity by 53.8-110.4 U/mg, while decreased the malondialdehyde (MDA) content by 37.4%-64.8%, myeloperoxidase (MPO) activity by 29.0%-46.9%, and the concentration of nitric oxide (NO) by 24.8-35.6 μmol/L. IOP treatment also promoted the secretion of interleukin (IL)-10 but suppressed those of interleukin (IL)-6, interleukin (IL)-1β and tumor necrosis factor (TNF)-α. Simultaneously, analysis of high-throughput sequencing indicated that IOP reduced the ratio of Firmicutes to Bacteroidetes (F/B) at phylum level, and increased the relative abundance of Bacteroides and Lactobacillus at genus level. In brief, IOP may be a promising alternative medicine for UC remedy by regulating the anti-inflammatory level, the anti-oxidative ability and the gut microbiota composition.

Mechanisms and clinical management of eosinophilic oesophagitis: an overview

Since the first description of eosinophilic oesophagitis (EoE) less than three decades ago, we have observed a striking increase in the number of patients diagnosed with EoE and the understanding of its clinical and immunopathogenic background. Nonetheless, a plethora of open questions await elucidation. In this Review, we discuss the current state of knowledge regarding the underlying mechanisms, particularly environmental factors and their interaction with genetic susceptibility. Subsequently, we discuss how to translate these factors into the diagnostic and therapeutic management of this chronic, immune-mediated disorder. Finally, we dissect the still long list of unmet needs, such as reasons for and handling refractory EoE and atypical clinical presentations. These open questions can guide us through future research steps and potentially foster reconsideration of the diagnostic guidelines of EoE.

Serum and Mucosal CD30 in Pediatric Inflammatory Bowel Diseases: Useful Biomarker for Diagnosis and Disease Activity Monitoring?

BACKGROUND

Inflammatory bowel diseases (IBD) frequently manifest in pediatric age, but may have atypical clinical, histological and laboratory features. Their underlying immune pathophysiology is incompletely understood, rendering quick diagnosis followed by tailored therapy difficult. The tumor necrosis factor superfamily receptor CD30 has been proposed as a potential marker of ulcerative colitis (UC) and has also been associated with elevated Th2 helper T cells.

METHODS

A cohort of pediatric patients with UC and Crohn's disease (CD) was evaluated for serum soluble CD30 (sCD30) using ELISA and expression of CD30 and subpopulations of Th1/Th2/Th17 lymphocytes in the gastrointestinal mucosa using flow cytometry (FCM). The dataset is supported by endoscopic and microscopic activity of the disease and basic laboratory markers of inflammation.

RESULTS

The cohort consisted of 102 observations from 94 patients. sCD30 levels did not differ between patients with CD or UC. However, sCD30 levels correlated with levels of CRP, ESR, fecal calprotectin and albumin and also with clinical activity of the disease in patients with both UC and CD. FCM was not helpful in evaluation of mucosal CD30, which was lowly expressed and not associated with the diagnosis or disease activity. We show augmented Th2 and Th1/17 response in terminal ileum and right-sided colon and decreased Th1/17 response in left-sided colon of UC patients. T lymphocyte subsets were also affected by anti-TNF treatment and patients' age.

CONCLUSIONS

Neither sCD30 nor mucosal CD30 expression was helpful in differentiating between UC and CD. sCD30 seems to reflect a degree of systemic inflammation and clinical activity in IBD.

Paeoniflorin-6'-O-benzene sulfonate protected the intestinal epithelial barrier by restoring the inhibitory effect of GRK2 and β-arrestin 2 on ERK1/2-NF-κB

Peoniflorin-6'-O-benzene sulfonate (CP-25) inhibited the activity of GRK2 to exert anti-inflammatory and immunomodulatory effects. This study aimed to investigate the effect of CP-25 the intestinal epithelial barrier and the mechanism. CaCO-2 cell monolayer and dextran sulfate salt (DSS)-induced colitis mouse model was used to evaluate intestinal epithelial barrier function in vitro and in vivo, respectively. Results showed that CP-25 prevented dysfunction of the intestinal epithelial barrier and inhibited NF-κB p65 activation in TNF-α-induced CaCO-2 cells. The colon structure destroyed in DSS-induced colitis mice was improved by CP-25. CP-25 has a role in inhibition membrane translocation of GRK2-β-arrestin 2 complex, stabilization of the binding of GRK2 and β-arrestin 2 to ERK1/2 in cytoplasm. Subsequently down-regulated the nuclear transcription and transactivation of NF-κB p65 via inhibiting its phosphorylation of Ser536, and Ser276, respectively and restored the epithelial barrier function. In conclusion, CP-25 inhibited ERK1/2-NF-κB activation and thereby protected the intestinal epithelial barrier, which was associated with restoring the inhibition of GRK2 and β-arrestin 2 on ERK1/2.

Exposure to Polypropylene Microplastics via Oral Ingestion Induces Colonic Apoptosis and Intestinal Barrier Damage through Oxidative Stress and Inflammation in Mice

Extensive environmental pollution by microplastics has increased the risk of human exposure to plastics. However, the biosafety of polypropylene microplastics (PP-MPs), especially of PP particles < 10 μm, in mammals has not been studied. Thus, here, we explored the mechanism of action and effect of exposure to small and large PP-MPs, via oral ingestion, on the mouse intestinal tract. Male C57BL/6 mice were administered PP suspensions (8 and 70 μm; 0.1, 1.0, and 10 mg/mL) for 28 days. PP-MP treatment resulted in inflammatory pathological damage, ultrastructural changes in intestinal epithelial cells, imbalance of the redox system, and inflammatory reactions in the colon. Additionally, we observed damage to the tight junctions of the colon and decreased intestinal mucus secretion and ion transporter expression. Further, the apoptotic rate of colonic cells significantly increased after PP-MP treatment. The expression of pro-inflammatory and pro-apoptosis proteins significantly increased in colon tissue, while the expression of anti-inflammatory and anti-apoptosis proteins significantly decreased. In summary, this study demonstrates that PP-MPs induce colonic apoptosis and intestinal barrier damage through oxidative stress and activation of the TLR4/NF-κB inflammatory signal pathway in mice, which provides new insights into the toxicity of MPs in mammals.

Mucoadhesive Nanoparticles Enhance the Therapeutic Effect of Dexamethasone on Experimental Ulcerative Colitis by the Local Administration as an Enema

Background

As the first-line drug to treat ulcerative colitis (UC), long-term use of glucocorticoids (GCs) produces severe toxic and side effects. Local administration as enema can increase the local GCs concentrations and reduce systemic exposure to high oral doses by directly delivering GCs to the inflammation site in the distal colorectum. However, UC patients are often accompanied by diarrhea, leading to the short colonic residence time of GCs and failure to exert their function fully.

Purpose

A kind of mucoadhesive nanoparticles (NPs) loading different dexamethasone derivatives (DDs) were developed, which could attach to the positively charged inflammatory colonic mucosa through electrostatic adsorption after administered by enema, thereby improving the local concentration and achieving effective targeted therapy for UC.

Methods

Two DDs, dexamethasone hemisuccinate and dexamethasone phosphate, were synthesized. In NPs preparation, The core PEI-DDs NPs were built by the electrostatic adsorption of DDs and the cationic polymer polyethyleneimine (PEI). Then, the natural polyanionic polysaccharide sodium alginate (SA) was electronically coated around NPs to construct the final SA-PEI-DDs NPs, followed by the in vitro stability and release tests, in vitro and in vivo colonic mucosal adhesion tests. In the in vivo anti-UC test, the experimental colitis mice were induced by 2,4,6-trinitrobenzenesulfonic acid. The body weight and disease activity index changes were measured, and the myeloperoxidase activity, pro-inflammatory cytokines concentration, and hematoxylin and eosin staining were also investigated to evaluate the therapeutic effect of NPs.

Results

The structures of two DDs were demonstrated by ¹H-NMR and MS. Both NPs were negatively charged and achieved high loading efficiency of DDs, while their particle sizes were significantly different. NPs showed good stability and sustained release properties in the simulated colonic environment. Moreover, the negative charge on the of NPs surface made them easier to adhere to the positively charged inflammatory colonic mucosa, thereby enhancing the enrichment and retention of DDS in the colitis site. Furthermore, the NPs exhibited better therapeutic effects than free Dex on the experimental colitis mice induced by TNBS through the enema rectal.

Conclusion

These results indicated the mucoadhesive NPs as a kind of novel nano-enema showed great potential to achieve efficient treatment on UC.

Multi-omics reveals diet-induced metabolic disorders and liver inflammation via microbiota-gut-liver axis

The gut microbiota medicated gut-liver axis is vital for liver function and health. We aimed to explore the underlying molecular mechanism of diet-induced metabolic liver disorders via microbiota-gut-liver axis using multi-omics. Metataxonomics, metaproteomics, transcriptomics, and metabolomics were conducted on liver tissue and biofluids (gastrointestinal contents and blood) to elucidate the microbial mechanism related to metabolic disorders and liver injury. The hepatic inflammation occurred based on histomorphology after feeding a long-term grain-based high-energy diet, and the serum biochemical parameters and proinflammatory cytokines were significantly activated. Metaproteomics analysis indicated that the high-energy diet reduced anti-infection, immunity, anti-oxidant functions, and increased cell death and damage of rumen microbiome. Ruminal Ruminococcus_2, Solobacterium, and Syntrophococcu and jejunal Pirellula were potential microbial markers of liver disorders. The high-energy diet promoted hepatic inflammatory response and cytokine/chemokine-mediated signaling pathways located in the core of the functional genomic network. The high-energy diet increased indoxyl sulfate and p-cresol sulfate and decreased triterpenoids in the liver that were the potential biomarkers associated with metabolic liver disorders. Integrated multi-omics analyses showed interactions among the rumen and jejunum microbiota, circulating metabolites, and liver gene expression, suggesting a systemic immune response and liver disorder that signals through the microbiota-gut-liver axis.

Metabolite features of serum and intestinal microbiota response of largemouth bass (Micropterus salmoides) after Aeromonas hydrophila challenge

The enteric morphology, enteric microbiota structure and serum metabolomics of M. salmoides before and after infected by A. hydrophila were analysed to explore the pathogenic mechanism of A. hydrophila infection in M. salmoides. The results revealed that, after the infection of A. hydrophila, the villus boundary of largemouth bass became less obvious; the relative abundance of Proteobacteria and decreasing relative abundance of Tenericutes were increasing; genera relative abundance of putatively beneficial bacteria (Mycoplasma) were decreasing, whereas the genus Aeromonas increased after infection; serum metabolomic analysis showed that infection with A. hydrophila caused disorder to the metabolic processes of largemouth bass, particularly amino acid metabolism, and caused inflammation; several potential pathogen infection-related and significantly differential intestinal microbiota-related metabolite markers were identified, such as 6-hydroxy-5-methoxyindole glucuronide, zalcitabine, bilirubin, aciclovir. This study may provide new insights into the potential association between enteric microbiota and serum metabolism and the pathogenic mechanism of M. salmoides infected by A. hydrophila, providing a scientific basis for disease control in largemouth bass breeding.

Advances in the Clinical Application of Histamine and Diamine Oxidase (DAO) Activity: A Review

The serum level of diamine oxidase (DAO) reflects the integrity and maturation of the small intestinal mucosa. This measure is important in diagnosing various diseases, including chronic urticaria tachyphylaxis, multiple organ dysfunction syndrome, preterm abortion, and migraine. This review aimed to summarize the findings of previous studies on the changes in DAO levels in diverse diseases and the application of this enzyme in the clinical setting, as well as the roles of this enzyme under physiological and pathological conditions. The advances in the mechanism and clinical application of DAO presented in this review will contribute to a better understanding of this enzyme and open up new and broader perspectives for future basic research and clinical applications.

Embelin alleviates weaned piglets intestinal inflammation and barrier dysfunction via PCAF/NF-κB signaling pathway in intestinal epithelial cells

BACKGROUND

Intestinal barrier plays key roles in maintaining intestinal homeostasis. Inflammation damage can severely destroy the intestinal integrity of mammals. This study was conducted to investigate the protective effects of embelin and its molecular mechanisms on intestinal inflammation in a porcine model. One hundred sixty 21-day-old castrated weaned pigs (Duroc × Landrace × Yorkshire, average initial body weight was 7.05 ± 0.28 kg, equal numbers of castrated males and females) were allotted to four groups and fed with a basal diet or a basal diet containing 200, 400, or 600 mg embelin/kg for 28 d. The growth performance, intestinal inflammatory cytokines, morphology of jejunum and ileum, tight junctions in the intestinal mucosa of piglets were tested. IPEC-1 cells with overexpression of P300/CBP associating factor (PCAF) were treated with embelin, the activity of PCAF and acetylation of nuclear factor-κB (NF-κB) were analyzed to determine the effect of embelin on PCAF/NF-κB pathway in vitro.

RESULTS

The results showed that embelin decreased (P < 0.05) serum D-lactate and diamine oxidase (DAO) levels, and enhanced the expression of ZO-1, occludin and claudin-1 protein in jejunum and ileum. Moreover, the expression levels of critical inflammation molecules (interleukin-1β, interleukin-6, tumor necrosis factor-α, and NF-κB) were down-regulated (P < 0.05) by embelin in jejunal and ileal mucosa. Meanwhile, the activity of PCAF were down-regulated (P < 0.05) by embelin. Importantly, transfection of PCAF siRNAs to IPEC-1 cell decreased NF-κB activities; embelin treatment downregulated (P < 0.05) the acetylation and activities of NF-κB by 31.7%-74.6% in IPEC-1 cells with overexpression of PCAF.

CONCLUSIONS

These results suggested that embelin ameliorates intestinal inflammation in weaned pigs, which might be mediated by suppressing the PCAF/NF-κB signaling pathway.

The mitochondrial UPR regulator ATF5 promotes intestinal barrier function via control of the satiety response

Organisms use several strategies to mitigate mitochondrial stress, including the activation of the mitochondrial unfolded protein response (UPR^mt). The UPR^mt in Caenorhabditis elegans, regulated by the transcription factor ATFS-1, expands on this recovery program by inducing an antimicrobial response against pathogens that target mitochondrial function. Here, we show that the mammalian ortholog of ATFS-1, ATF5, protects the host during infection with enteric pathogens but, unexpectedly, by maintaining the integrity of the intestinal barrier. Intriguingly, ATF5 supports intestinal barrier function by promoting a satiety response that prevents obesity and associated hyperglycemia. This consequently averts dysregulated glucose metabolism that is detrimental to barrier function. Mechanistically, we show that intestinal ATF5 stimulates the satiety response by transcriptionally regulating the gastrointestinal peptide hormone cholecystokinin, which promotes the secretion of the hormone leptin. We propose that ATF5 protects the host from enteric pathogens by promoting intestinal barrier function through a satiety-response-mediated metabolic control mechanism.