Human Intestinal Barrier Function in Health and Disease

A smart probe for detection of sugar markers for applications in gastrointestinal barrier dysfunction

Gastrointestinal (GI) barrier dysfunction is an early pathogenic event in many complex diseases. Despite the routine applications of invasive tests, saccharide molecules are used noninvasively for assessing GI tract mucosal barrier function. However, currently available methods for quantification of saccharides molecules are costly and laborious. Simplified, reliable, and high-throughput methods are desired so that GI permeability testing can become routine and widely used. Here, we have developed a one-component system comprising of a naphthyl-pyridine core coupled to a boronic acid receptor, which can be used for early detection of saccharide biomarkers (i.e., lactulose) for applications related to GI barrier dysfunction. For quantitation of lactulose as a model biomarker, we have designed gold nanoparticle decorated surfaces in a highly scalable 96-well format to enable sensitive testing of lactulose within a broad range of concentrations. To tackle current challenges in saccharide biomarker sensing, we developed a hybrid sensing principle integrating two optical modalities (plasmonics and fluorescence) with a synthetic smart-probe (naphthyl-pyridinium) for monitoring GI permeability. This technology can be further developed as an affordable and portable diagnostic tool for GI permeability screening for routine use, facilitating early detection of various diseases affecting the GI tract.

Altered diversity and composition of gut microbiota in Korean children with food allergy

BACKGROUND

This study aimed to comprehensively characterize the gut microbiome and identify individual and grouped gut microbes associated with food allergy (FA) using 16S rRNA gene sequencing.

METHODS

Fecal samples were collected from children with IgE-mediated FA and from sex- and age-matched controls. The V3-V4 variable regions of the 16S rRNA gene of the gut microbiome were profiled using next-generation sequencing (Illumina, USA). Bacterial species richness, intracommunity diversity, and intergroup dissimilarity were evaluated. Functional profiles were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) and the Minimal Set of Pathways (MinPath) algorithm.

RESULTS

Fecal samples were collected from children with IgE-mediated FA (n = 66) and from sex- and age-matched controls (n = 22). Gut microbiome richness (p < 0.0001), intra-community diversity (p < 0.0001), and inter-community diversity (p = 0.0004) were higher in the healthy group than in the FA group. Patients with FA were enriched in Blautia, Fusicatenibacter, and Ruminococcus_g5 compared with healthy control individuals (all p < 0.05). Healthy control individuals were significantly enriched in Oscillibacter and Ruminococcus compared with patients with FA (all p < 0.05). Functional pathway analysis identified enrichment in pathways related to endoglucanase in healthy controls and the ATP-binding cassette (ABC) transport system in FA patients.

CONCLUSIONS

The gut microbiomes of patients with FA and healthy control individuals had different taxonomic abundances, and the microbiome richness and diversity of the bacterial flora of patients with FA were reduced compared with controls.

Oxidized yeast glucan alleviates lead-induced toxicity in mice by improving intestinal health to inhibit Pb absorption and reducing kidney oxidative stress

This study investigated the protective effects and Pb-excretion mechanisms of yeast glucans (YG) with varying oxidation degrees in Pb-exposed mice. Results demonstrated that all three glucans effectively reduced blood lead levels, alleviated inflammation, and mitigated liver damage in Pb-exposed mice, with highly oxidized yeast glucan (OYG2) exhibiting the greatest efficacy. Furthermore, the glucans attenuated Pb-induced oxidative stress and pathological changes in the kidney by elevating glutathione and superoxide dismutase levels, thereby restoring renal excretory function (blood urea nitrogen and creatinine). This restoration contributed to maintaining electrolyte homeostasis (Na+, Cl-, K+) and significantly enhanced lead excretion efficiency via urine. Additionally, the glucans modulated intestinal microbiota balance, promoted short-chain fatty acid production, and repaired Pb-induced intestinal barrier damage by upregulating tight junction proteins (ZO-1, Occludin, Claudin-1). In conclusion, yeast glucans, particularly OYG2, effectively inhibited Pb absorption and facilitated its excretion through feces, highlighting their potential as a therapeutic strategy for lead toxicity.

Microfluidic organ-on-a-chip models for the gut-liver axis: from structural mimicry to functional insights

The gut-liver axis plays a crucial role in maintaining metabolic balance and overall human health. It orchestrates various processes, such as blood flow, nutrient transfer, metabolite processing, and immune cell communication between the two organs. Traditional methods, such as animal models and two-dimensional (2D) cell cultures, are insufficient in fully replicating the intricate functions of the gut-liver axis. The emergence of microfluidic technology has revolutionized this field, facilitating the development of organ-on-a-chip (OOC) systems. These systems are capable of mimicking the complex structures and dynamic environments of the gut and liver in vitro and incorporating sensors for real-time monitoring. In this article, we review the latest progress in gut-on-a-chip (GOC) and liver-on-a-chip (LOC) systems, as well as the integrated gut-liver-on-a-chip (GLOC) models. Our focus lies in the simulation of physiological parameters, three-dimensional (3D) structural mimicry, microbiome integration, and multicellular co-culture. All these aspects are essential for constructing accurate in vitro models of the gut and liver. Furthermore, we explore the current applications of OOC technology in the study of the gut and liver, including its use in disease modeling, toxicity testing, and drug screening. Finally, we discuss the challenges that remain and outline potential future directions for advancing GOC and LOC development in vitro.

Isolation of Bacillus cereus and its probiotic effect on growth performance, antioxidant capacity, and intestinal barrier protection of broilers

Probiotics are effective for improving poultry health. Probiotic Bacillus cereus strains are widely used to improve animal health by stimulating the immune system. In this study, we obtained a B. cereus 13 (BC13) strain that functions in acid, high-temperature, and bile salt resistance. It also degrades starch, cellulose, and other proteins. To better understand the probiotic effects of BC13, we added the strain to the diet of broilers and observed its effects. We found that BC13 significantly improved the growth performance of broilers. The levels of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase were increased, and the concentration of malondialdehyde was reduced by BC13. Supplementation with BC13 enhanced immune function by increasing the levels of secretory immunoglobulin A (sIgA) in the jejunum mucosa; IgA, IgM, and IgG in the serum; mRNA levels of Zo-1, claudin and occludin of the jejunal mucosa; and increased villus height/crypt depth of the jejunum. Furthermore, BC13 improved the composition of intestinal microbes, especially at the genus level of Akkermansia. The addition of BC13 increased the levels of acetic, butyric, valeric, and propionic acids. These results emphasise the potential of BC13 as a probiotic dietary supplement to improve the antioxidant capacity, intestinal barrier function, and gut microbial composition to enhance body health.

Alteration of the Microbiota with Vancomycin and High-Fibre Diet Affects Short-Chain Fatty Acid/Free Fatty Acid Receptor Signalling in Rat Caecum

Microbial short-chain fatty acids (SCFA) regulate intestinal functions via free-fatty acid (FFA) receptors type 2 and 3. Though the caecum is the most important fermentation chamber in many species, it is unknown whether this signalling system is modulated in dependence on the rate of fermentation within the lumen of this part of the large intestine. Thus, we asked the question whether alteration of the microbiota composition by antibiotic treatment or high-fibre diet affects the SCFA/FFA signalling using rat caecum as model system. SCFA concentrations and microbiota were analysed in caecal samples from untreated rats, following vancomycin treatment, or after feeding with a high-fibre diet. Oral and aboral caecal segments were harvested for Ussing chamber experiments paralleled by Ca2+ imaging experiments with Fura-2 loaded crypts, immunofluorescence, and qPCR. Vancomycin treatment reduced total SCFA concentrations in the caecal content, whereas the high-fibre diet increased the concentration of acetate, but reduced that of propionate and butyrate. Propionate-induced anion secretion was abolished in the vancomycin group, whereas it nearly doubled in the high-fibre group. These effects could not be explained by changes in the expression of FFA2 receptor or in Ca2+ signalling evoked by FFA2 receptor activation. Parallel changes in ion secretion evoked by carbachol suggest that alterations in cholinergic signalling might be responsible for the observed changes in epithelial ion transport. Additionally, mucosal mast cell and enterochromaffin cell density increased after vancomycin and high-fibre diet, respectively. This study emphasizes the complex interactions between the microbiota and the caecal epithelium focusing on SCFA/FFA signalling.

Oral Exposure to Clostridium difficile Toxin A Aggravates Food Allergy by Intestinal Barrier Destruction, Mast Cell Activation, and Th2-Biased Immune Responses

Food allergy is a complex disease, with multiple environmental factors involved. Considering the regulatory effect of Clostridium difficile toxin A (Tcd A) on biological processes of allergic reactions, the role of oral exposure to Tcd A on food allergy was investigated. The intestinal permeability and β-hexosaminidase were promoted by Tcd A using the in vitro Caco-2 and HT-29 cells coculture monolayer and bone marrow-derived mast cell (MCs) degranulation model. When the sensitized mice were challenged with OVA and 4 μg of Tcd A, specific IgE and MCPT-1 levels were increased. The results of flow cytometry and ELISA demonstrated that the Th1 and Treg cells were reduced and higher IL-5 was induced. The jejunum staining showed that villus injury and MC accumulation were aggravated. All of the findings demonstrated that Tcd A could aggravate food allergy, and the orally exposed risk factors aggravating food allergy warrant increasing attention.

Impact of liposomal hesperetin in broilers: prospects for improving performance, antioxidant potential, immunity, and resistance against Listeria monocytogenes

Liposomal encapsulated phytogenics, such as liposomal hesperetin, are considered novel substitutes for antibiotics in the broiler industry owing to their improved nutritional and therapeutic properties. Therefore, our key goal was to investigate liposomal hesperetin impact on broiler growth performance, health, antioxidant status, tight junction proteins (TJP), and resistance against Listeria monocytogenes. Four broiler groups were fed 0, 150, 250, or 400 mg/kg of liposomal hesperetin-supplemented diets and experimentally infected with L. monocytogenes strain. Herein, liposomal hesperetin, especially at higher concentrations, augmented broilers FCR with upregulation of genes encoding TJP (occludin, JAM-2, MUC-2), and antioxidant attributes (GPX-1, SOD-1, CAT, HO-1, NQO1, COX2), which reflect enhancing health and welfare of broilers. Muscle antioxidant biomarkers were enhanced; meanwhile, muscle MDA, ROS, and H2O2 levels were reduced in response to 400 mg/kg of liposomal hesperetin. Liposomal hesperetin fortification reduced L. monocytogenes loads and expression levels of its virulence-related genes (flaA, hlyA, and ami). Remarkably, histopathological alterations in intestinal and brain tissues of L. monocytogenes-infected broilers were restored post-inclusion at higher levels of liposomal hesperetin, which reflects increase of the birds' resistance to L. monocytogenes infection. Transcription levels of genes encoding cytokines/chemokines (MyD88, AVBD6, CCL20, IL-1β, IL-18), and autophagy (Bcl-2, LC3, AMPK, AKT, CHOP, Bip, p62, XBP1) were ameliorated following dietary liposomal hesperetin fortification, which suggests enhancement of the birds' immunity and health. Collectively, our research recommends liposomal hesperetin application in broiler diets owing to its promoting impact on growth performance, antioxidant status, immunity, health, and welfare besides its antibacterial, and antivirulence characteristics to fight against L. monocytogenes.

The Role of the Intestinal Flora and Its Derivatives in Neurocognitive Disorders: A Narrative Review from Surgical Perspective

Perioperative neurocognitive dysfunction is a significant concern for population health, impacting postoperative recovery and increasing the financial burden on patients. With an increasing number of surgical procedures being performed, the prevention and management of perioperative neurocognitive dysfunction have garnered significant attention. While factors such as age, lifestyle, genetics, and education are known to influence the development of cognitive dysfunction, recent research has highlighted the role of the gut microbiota in neurological health. An increased abundance of pro-inflammatory gut microbiota can trigger and worsen neuroinflammation, neuronal cell damage, and impaired cellular autophagy. Moreover, the inflammation-promoting gut microbiota can disrupt immune function, impair neuroautophagy, and affect the production and circulation of extracellular vesicles and neurotransmitters. These factors collectively play a role in the onset and advancement of cognitive impairment. This narrative review delves into the molecular mechanisms through which gut microbiota and their derivatives contribute to cognitive impairment, focusing on the impact of anesthesia surgery, changes in gut microbial populations, and perioperative cognitive impairment associations. The study suggests that alterations in the abundance of various bacterial species and their metabolites pre- and post-surgery may be linked to postoperative cognitive impairment. Furthermore, the potential of probiotics or prebiotics in addressing cognitive impairment is discussed, offering a promising avenue for investigating the treatment of perioperative neurocognitive disorders.

Fucoidan alleviated colitis aggravated by fiber deficiency through protecting the gut barrier, suppressing the MAPK/NF-κB pathway, and modulating gut microbiota and metabolites

Insufficient dietary fiber intake has become a global public health issue, affecting the development and management of various diseases, including intestinal diseases and obesity. This study showed that dietary fiber deficiency enhanced the susceptibility of mice to colitis, which could be attributed to the disruption of the gut barrier integrity, activation of the NF-κB pathway, and oxidative stress. Undaria pinnatifida fucoidan (UPF) alleviated colitis symptoms in mice that fed with a fiber deficient diet (FD), characterized by increased weight gain and reduced disease activity index, liver and spleen indexes, and histological score. The protective effect of UPF against FD-exacerbated colitis can be attributed to the alleviation of oxidative stress, the preservation of the gut barrier integrity, and inhibition of the MAPK/NF-κB pathway. UPF ameliorated the gut microbiota composition, leading to increased microbiota richness, as well as increased levels of Muribaculaceae, Lactobacillaceae, and Bifidobacterium and reduced levels of Proteobacteria, Bacteroidetes, and Bacteroides. Metabolomics analysis revealed that UPF improved the profile of microbiota metabolites, with increased levels of carnitine and taurine and decreased levels of tyrosine and deoxycholic acid. This study suggests that UPF has the potential to be developed as a novel prebiotic agent to enhance human health.

Role of polyamines in intestinal mucosal barrier function

The intestinal epithelium is a rapidly self-renewing tissue; the rapid turnover prevents the invasion of pathogens and harmful components from the intestinal lumen, preventing inflammation and infectious diseases. Intestinal epithelial barrier function depends on the epithelial cell proliferation and junctions, as well as the state of the immune system in the lamina propria. Polyamines, particularly putrescine, spermidine, and spermine, are essential for many cell functions and play a crucial role in mammalian cellular homeostasis, such as that of cell growth, proliferation, differentiation, and maintenance, through multiple biological processes, including translation, transcription, and autophagy. Although the vital role of polyamines in normal intestinal epithelial cell growth and barrier function has been known since the 1980s, recent studies have provided new insights into this topic at the molecular level, such as eukaryotic initiation factor-5A hypusination and autophagy, with rapid advances in polyamine biology in normal cells using biological technologies. This review summarizes recent advances in our understanding of the role of polyamines in regulating normal, non-cancerous, intestinal epithelial barrier function, with a particular focus on intestinal epithelial renewal, cell junctions, and immune cell differentiation in the lamina propria.

Fecal microbiota transplantation attenuates Alzheimer's disease symptoms in APP/PS1 transgenic mice via inhibition of the TLR4-MyD88-NF-κB signaling pathway-mediated inflammation

Alzheimer's disease (AD) is a prevalent and progressive neurodegenerative disorder that is the leading cause of dementia. The underlying mechanisms of AD have not yet been completely explored. Neuroinflammation, an inflammatory response mediated by certain mediators, has been exhibited to play a crucial role in the pathogenesis of AD. Additionally, disruption of the gut microbiota has been found to be associated with AD, and fecal microbiota transplantation (FMT) has emerged as a potential therapeutic approach. However, the precise mechanism of FMT in the treatment of AD remains elusive. In this study, FMT was performed by transplanting fecal microbiota from healthy wild-type mice into APP/PS1 mice (APPswe, PSEN1dE9) to assess the effectiveness of FMT in mitigating AD-associated inflammation and to reveal its precise mechanism of action. The results demonstrated that FMT treatment improved cognitive function and reduced the expression levels of inflammatory factors by regulating the TLR4/MyD88/NF-κB signaling pathway in mice, which was accompanied by the restoration of gut microbial dysbiosis. These findings suggest that FMT has the potential to ameliorate AD symptoms and delay the disease progression in APP/PS1 mice.

Role of Akkermansia muciniphila in insulin resistance

Insulin resistance (IR) is a pathogenic factor in numerous metabolic diseases. The gut microbiota plays a crucial role in maintaining the function of the intestinal barrier and overall human health, thereby influencing IR. Dysbiosis of the gut microbiota can contribute to the development of IR. Therefore, it is essential to maintain a balanced and diverse gut microbiota for optimal health. Akkermansia muciniphila, a widely present microorganism in the human intestine, has been shown to regulate gastrointestinal mucosal barrier integrity, reduce endotoxin penetration, decrease systemic inflammation levels, and improve insulin sensitivity. Reduced abundance of A. muciniphila is associated with an increased risk of IR and other metabolic diseases, highlighting its correlation with IR. Understanding the role and regulatory mechanism of A. muciniphila is crucial for comprehending IR pathogenesis and developing novel strategies for preventing and treating related metabolic disorders. Individual variations may exist in both the gut microbiota composition and its impact on IR among different individuals. Further investigation into individual differences between A. muciniphila and IR will facilitate advancements in personalized medicine by promoting tailored interventions based on the gut microbiota composition, which is a potential future direction that would optimize insulin sensitivity while preventing metabolic disease occurrence. In this review, we describe the physiological characteristics of A. muciniphila, emphasize its roles in underlying mechanisms contributing to IR pathology, and summarize how alterations in its abundance affect IR development, thereby providing valuable insights for further research on A. muciniphila, as well as new drug development targeting diabetes.

TGF-β2, EGF and FGF21 influence the suckling rat intestinal maturation

Some of the growth factors present in breast milk, such as transforming growth factor-β (TGF-β), epidermal growth factor (EGF) and fibroblast growth factor 21 (FGF21), play important roles in the development of the intestinal tract. The aim of this study was to determine the effect of a supplementation with TGF-β2, EGF and FGF21 on suckling rats intestinal maturation. For this purpose, Wistar rats were supplemented daily with TGF-β2, EGF or FGF21 throughout the suckling period. We evaluated the functionality of the intestinal epithelial barrier through an in vivo dextran permeability assay, and by a histomorphometric and immunohistochemical study. In addition, the intestinal gene expression of tight junction-associated proteins, mucins, toll-like receptors, and maturation markers was analyzed. Moreover, the intraepithelial lymphocyte (IEL) phenotypical composition was established. During the suckling period, the supplementation with TGF-β2, EGF and FGF21 showed important signs of intestinal maturation. These results suggest that these molecules, present in breast milk, play a modulatory role in the maturation of the intestinal barrier function and the IEL composition during the suckling period.

Bifidobacterium longum JBLC-141 alleviates hypobaric hypoxia-induced intestinal barrier damage by attenuating inflammatory responses and oxidative stress

Hypobaric hypoxia exposure occurs at high altitudes, including plateaus, and affects normal intestinal function and microbiota composition. Exposure induces an intestinal inflammatory response and oxidative stress injury, ultimately disrupting intestinal homeostasis and causing barrier damage. Thus, due to its anti-inflammatory, antioxidative, and intestinal microbiota-regulating properties, Bifidobacterium longum is a potentially effective probiotic intervention to protect the intestinal barrier during low-pressure hypoxia on plateaus. However, its mechanism of action is not fully defined. In this study, we investigate the mechanism by which B. longum intervenes in intestinal barrier damage caused by plateau low-pressure hypoxia. To this end, an in vivo model is established by exposing rats to a simulated low-pressure hypoxic plateau environment. The experimental rats were subsequently supplemented with a B. longum strain (JBLC-141) extracted from the feces of healthy adults in Bama, Guangxi. B. longum JBLC-141 mitigates the effects of plateau low-pressure hypoxia on the rat intestinal barrier. This is achieved by activating the intestinal Kelch-like ECH-associated protein 1 (KEAP1)/nuclear factor erythroid 2-related factor 2 (NRF2) pathway, alleviating plateau hypoxia-induced intestinal oxidative stress injury. B. longum JBLC-141 also attenuates the inflammatory response and upregulates the expression of the tight junction proteins claudin-1, occludin, and zonula occludens-1. Furthermore, it reduces intestinal permeability, effectively ameliorating and repairing the barrier histological damage induced by the plateau low-pressure hypoxic environment. In addition, B. longum JBLC-141 positively regulates the intestinal microbiota, increasing the relative abundance of beneficial bacteria while reducing that of pathogenic bacteria and maintaining intestinal flora homeostasis in rats.

An in vitro investigation on the physicochemical properties of different quercetin formulations

OBJECTIVES

Quercetin is a naturally occurring plant flavonoid commonly used as a nutritional supplement due to its antioxidant and anti-inflammatory properties. Its well-known low bioavailability has led to the design of different quercetin formulations by various commercial entities seeking to market a highly bioavailable quercetin product. This study investigates four different commercially available quercetin formulations (LMQ, QUX, QUO, and QUV) for their physicochemical properties that influence bioavailability. LMQ and QUX are liquid-based formulations while QUO and QUV are solid powder-based formulations.

METHODS

Studies were conducted on particle size using a particle size analyzer; solubility (in water, simulated gastric and intestinal fluid) using Ultra High Performance Liquid Chromatography (UHPLC) to quantify the quercetin content; intestinal permeability and toxicity using Caco-2 cells and HepG2 liver cells.

RESULTS

LMQ and QUX had the narrowest particle size distribution as well as the highest solubility while QUO and QUV had the widest particle size distribution but the poorest solubility. One formulation (QUO) exhibited a significant reduction in cell viability with HepG2 and Caco-2 cells including a significant decrease in TEER value change (-39.0 %; p<0.01); its higher Caco-2 cell permeability (Papp 2.85 × 10-4 ± 4.22 × 10-5; p<0.05) likely resulted from reduced membrane integrity. The other formulations significantly increased the TEER value within the first 4 h (≥22.7 %; p<0.05).

CONCLUSIONS

The particle size distribution of each of the individual formulations reflected their solubilities in water and gastrointestinal fluids. Despite QUO having the highest permeability, its negative change in TEER value over time revealed its evident cytotoxic effects. QUV performed poorly in terms of solubility, and permeability. LMQ and QUX were the most consistent across each study with LMQ performing better than QUX overall. Findings of this study present one formulation (LMQ) with superior intestinal absorption while maintaining high cell viability, thus making it one of the safer and more effective quercetin formulations.

Fecal microbiota transplantation from postmenopausal osteoporosis human donors accelerated bone mass loss in mice

Objectives

To investigate the effect of gut microbiota from postmenopausal osteoporosis patients on bone mass in mice.

Methods

Fecal samples were collected from postmenopausal women with normal bone mass (Con, n=5) and postmenopausal women with osteoporosis (Op, n=5). Microbial composition was identified by shallow shotgun sequencing. Then fecal samples were transplanted into pseudo-sterile mice previously treated with antibiotics for 4 weeks. These mice were categorized into two groups: the Vehicle group (n=7) received fecal samples from individuals with normal bone mass, and the FMT group (n=7) received fecal samples from individuals with osteoporosis. After 8 weeks, bone mass, intestinal microbial composition, intestinal permeability and inflammation were assessed, followed by a correlation analysis.

Results

The bone mass was significantly reduced in the FMT group. Microbiota sequencing showed that Shannon index (p < 0.05) and Simpson index (p < 0.05) were significantly increased in Op groups, and β diversity showed significant differences. the recipient mice were similar. linear discriminant analysis effect size (LEfSe) analysis of mice showed that Halobiforma, Enterorhabdus, Alistipes, and Butyricimonas were significantly enriched in the FMT group. Lachnospiraceae and Oscillibacter were significantly enriched in the Vehicle group. H&E staining of intestinal tissues showed obvious intestinal mucosal injury in mice. Intestinal immunohistochemistry showed that the expression of Claudin and ZO-1 in the intestinal tissue of the FMT group mice was decreased. The FITC-Dextran (FD-4) absorption rate and serum soluble CD14 (sCD14) content were increased in FMT mice. Correlation analysis showed that these dominant genera were significantly associated with bone metabolism and intestinal permeability, and were associated with the enrichment of specific enzymes. Serum and bone tissue inflammatory cytokines detection showed that the expression of TNF-α and IL-17A in the FMT group were significantly increased.

Conclusion

Overall, our findings suggested gut microbiota from postmenopausal osteoporosis patients accelerate bone mass loss in mice. Aberrant gut microbiota might play a causal role in the process of bone mass loss mediated by inflammation after the destruction of the intestinal barrier.

The oral-gut microbiome axis in health and disease

The human body hosts trillions of microorganisms throughout many diverse habitats with different physico-chemical characteristics. Among them, the oral cavity and the gut harbour some of the most dense and diverse microbial communities. Although these two sites are physiologically distinct, they are directly connected and can influence each other in several ways. For example, oral microorganisms can reach and colonize the gastrointestinal tract, particularly in the context of gut dysbiosis. However, the mechanisms of colonization and the role that the oral microbiome plays in causing or exacerbating diseases in other organs have not yet been fully elucidated. Here, we describe recent advances in our understanding of how the oral and intestinal microbiota interplay in relation to their impact on human health and disease.

Protective effects of insoluble dietary fiber from cereal bran against DSS-induced chronic colitis in mice: From inflammatory responses, oxidative stress, intestinal barrier, and gut microbiota

Insoluble dietary fiber (IDF) is a crucial component of cereals, and IDF from cereal bran (IDF-CB) has been reported to have multiple biological activities. However, the effect of IDF-CB on chronic colitis remains underexplored. The study aimed to investigate the impact of IDFs from wheat bran (WBIDF), rice bran (RBIDF), millet bran (MBIDF) and oat bran (OBIDF) on chronic colitis induced by dextran sulfate sodium (DSS). Our findings demonstrated that IDFs-CB supplementation mitigated DSS-induced weight loss and reduced lesions in the colon and spleen. Levels of proinflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) and oxidative stress markers (MPO, iNOS and MDA)were decreased, and anti-inflammatory cytokine (IL-10) and T-SOD activity were increased after IDF-CB inclusion. Furthermore, IDFs-CB restored intestinal barrier function by regulating gene expression (up-regulated Muc-2, ZO-1 and Occludin, and down-regulated Claudin-1 and Claudin-4). Additionally, we analyzed the gut microbiota and SCFAs composition. WBIDF, MBIDF and OBIDF inhibited the growth of Muribaculaceae_unclassified, Bacteroides and Parasutterella. Conversely, IDFs-CB promoted the growth of Candidatus_Saccharimonas and norank_f__norank_o__Clostridia_UCG-014. Notably, WBIDF enhanced the abundance of Allobaculum, while MBIDF and OBIDF increased the abundance of Lachnospiraceae_NK4A136. Moreover, supplementation with IDFs-CB significantly elevated certain SCFA concentrations-particularly acetic acid and isohexanoic acid. Our results suggested that IDF-CB effectively alleviated DSS-induced chronic colitis; among them，WBIDF exhibited superior efficacy followed by OBIDF，MBIDF，and RBIDF. This study provides a theoretical foundation for dietary recommendations for patients suffering from inflammatory bowel disease.

Regulation of Isoleucine on Colonic Barrier Function in Rotavirus-Infected Weanling Piglets and Analysis of Gut Microbiota and Metabolomics

Rotavirus (RV) is a significant contributor to diarrhea in both young children and animals, especially in piglets, resulting in considerable economic impacts on the global pig industry. Isoleucine (Ile), a branched-chain amino acid, is crucial for regulating nutrient metabolism and has been found to help mitigate diarrhea. This study aimed to assess the impact of isoleucine supplementation in feed on colonic barrier function, colonic microbiota, and metabolism in RV-infected weanling piglets. A total of thirty-two weaned piglets, aged 21 days, were randomly assigned to two dietary groups (each further divided into two subgroups, with eight replicates in each subgroup), receiving diets with either 0% or 1% isoleucine for a duration of 14 days. One group from each treatment was then challenged with RV, and the experimental period lasted for 19 days. The results showed that dietary Ile significantly increased the secretion of IL-4, IL-10, and sIgA in the colon of RV-infected weanling piglets (p < 0.05). In addition, Ile supplementation notably increased the expression of tight junction proteins, including Claudin-3, Occludin, and ZO-1 (p < 0.01), as well as the mucin protein MUC-1 in the colon of RV-infected weanling piglets (p < 0.05). Gut microbiota analysis revealed that dietary Ile increased the relative abundance of Prevotella and decreased the relative abundance of Rikenellaceae in the colons of RV-infected weanling piglets. Compared with the RV+CON, metabolic pathways in the RV+ILE group were significantly enriched in vitamin digestion and absorption, steroid biosynthesis, purine metabolism, pantothenate and CoA biosynthesis, cutin, suberine, and wax biosynthesis, as well as fatty acid biosynthesis, and unsaturated fatty acid biosynthesis. In conclusion, dietary Ile supplementation can improve immunity, colonic barrier function, colonic microbiota, and colonic metabolism of RV-infected weaned piglets. These findings provide valuable insights into the role of isoleucine in the prevention and control of RV.

Inflammation-targeted delivery of Urolithin A mitigates chemical- and immune checkpoint inhibitor-induced colitis

Inflammatory bowel disease (IBD) treatment often involves systemic administration of anti-inflammatory drugs or biologics such as anti-TNF-α antibodies. However, current drug therapies suffer from limited efficacy due to unresponsiveness and adverse side effects. To address these challenges, we developed inflammation-targeting nanoparticles (ITNPs) using biopolymers derived from the gum kondagogu (Cochlospermum gossypium) plant. These ITNPs enable selective drug delivery to inflamed regions, offering improved therapeutic outcomes. We designed ITNPs that specifically bind to inflamed regions in both human and mouse intestines, facilitating more effective, uniform, and prolonged drug delivery within the inflamed tissues. Furthermore, we demonstrated that oral administration of ITNPs loaded with urolithin A (UroA), a microbial metabolite or its synthetic analogue UAS03 significantly attenuated chemical- and immune checkpoint inhibitor- induced colitis in pre-clinical models. In conclusion, ITNPs show great promise for delivering UroA or its analogues while enhancing therapeutic efficacy at lower doses and reduced frequency compared to free drug administration. This targeted approach offers a potential solution to enhance IBD treatment while minimizing systemic side effects.

Probiotics in piglet: from gut health to pathogen defense mechanisms

Various problems and obstacles are encountered during pig farming, especially the weaning phase when switching from liquid to solid feed. Infection by pathogenic bacteria causes damage to the intestinal barrier function of piglets, disrupts the balance of the intestinal microbiota, and destroys the chemical, mechanical, and immune barriers of the intestinal tract, which is one of the main causes of gut inflammation or gut diseases in piglets. The traditional method is to add antibiotics to piglet diets to prevent bacterial infections. However, long-term overuse of antibiotics leads to bacterial resistance and residues in animal products, threatening human health and causing gut microbiota dysbiosis. In this context, finding alternatives to antibiotics to maintain pre- and post-weaning gut health in piglets and prevent pathogenic bacterial infections becomes a real emergency. The utilization of probiotics in piglet nutrition has emerged as a pivotal strategy to promote gut health and defend against pathogenic infections, offering a sustainable alternative to traditional antibiotic usage. This review introduces recent findings that underscore the multifaceted roles of probiotics in enhancing piglet welfare, from fortifying the gut barrier to mitigating the impacts of common bacterial pathogens. Meanwhile, this study introduces the functions of probiotics from different perspectives: positive effects of probiotics on piglet gut health, protecting piglets against pathogen infection, and the mechanisms of probiotics in preventing pathogenic bacteria.

The effects of a 6-week intervention with Limosilactobacillus reuteri ATCC PTA 6475 alone and in combination with L. reuteri DSM 17938 on gut barrier function, immune markers, and symptoms in patients with IBS-D-An exploratory RCT

BACKGROUND

An increased intestinal permeability is a common feature in patients with diarrhoea-predominant irritable bowel syndrome (IBS-D). Probiotics have shown to improve IBS symptoms and might also affect intestinal barrier function.

AIM

The aim of this study was to investigate the effects of a 6-week intervention with Limosilactobacillus reuteri ATCC PTA 6475 alone (single strain) or in combination with Limosilactobacillus reuteri DSM 17938 (dual strain) on gut barrier function, immune markers, and symptoms in IBS-D patients (ClinicalTrials.gov registration number: NCT03986476).

METHODS

65 IBS-D patients were randomised into three groups (placebo, single strain, dual strain). Small and large intestinal permeability were assessed using a multi-sugar urinary recovery test. Blood, saliva, faecal samples, and several symptom scales were collected before, and after three and six weeks of intervention.

RESULTS

Small and large intestinal permeability as well as other markers of gut barrier function were not significantly affected by the probiotic interventions. Serum IL-6 levels showed a tendency to be reduced in the single strain group (descriptive p = 0.052). In addition, high-sensitivity C-reactive protein was significantly reduced in the dual strain group (p = 0.041). The participants in both treatment groups reported less gastrointestinal symptoms after three weeks, but this reached significance only in the dual strain group (total score: p = 0.032, pain subscore: p = 0.028). After six weeks, none of the assessed symptoms were significantly different from the placebo.

CONCLUSION

The probiotic compounds investigated in this study did not seem to affect IBS-D patients' gut barrier function, but showed potential anti-inflammatory and symptom-improving properties, which need to be confirmed in larger study cohorts.

Gastrointestinal Conditions Affect Chronic Pain and Quality of Life in Women

Pain is a chronic condition in many women; drugs used for its treatment are often accompanied by detrimental effects on many organs, including the gut. Once inflamed, the gut can affect pain processes. The aim of this study was to evaluate the general health of women suffering chronic pain, with particular attention to gastrointestinal (GI) conditions. The possibility to improve pain and quality of life through personalized nutritional advice was also tested. Forty women suffering from chronic pain were contacted for the administration of questionnaires to define their pain features and gastrointestinal conditions. Their psychological, clinical and reproductive states were also recorded. Pain scores were correlated with GI, psychological and clinical scores. Diet suggestions were given, and evaluation was repeated after 4 weeks. Thirty-eight women were included in the study: 32 suffered chronic widespread pain and had 6 pelvic pain. Pain had been present in all women for years; more than 80% of women reported various types of disorders related to the gut. Pain scores were worse in the women intolerant to milk and dairy products. The GI score was positively correlated with the pain score. The Dietary Inflammatory Index was very high in all subjects. Personalized nutritional advice followed by 26 subjects for 4 weeks resulted in a significant improvement of pain and quality of life parameters. We describe women with chronic pain as being particularly affected by GI alterations. The change in feeding habits had a beneficial effect on pain and other quality of life parameters.

Effects of high-dose glucose oxidase on broiler growth performance, antioxidant function, and intestinal microbiota in broilers

Glucose oxidase (GOD) has been investigated as a potential additive for enhancing intestinal health and growth performance in poultry. However, limited research exists on the effects of ultra-high doses of GOD in practical poultry production. This study aimed to investigate the impact of high dietary GOD levels on broiler growth performance, antioxidant capacity, and intestinal microbiota. A total of 400 healthy, 1-day-old, slow-growing broiler chickens were randomly assigned to four treatment groups. The control group was fed a standard basal diet, while the other groups (G1, G2, and G3) were fed the basal diet supplemented with 4 U/g, 20 U/g, and 100 U/g of VTR GOD, respectively. The results showed that a dose of 100 U/g GOD significantly improved the final body weight and average daily feed intake (ADFI) (p < 0.05). Additionally, the G3 group exhibited a marked increase in glutathione peroxidase (GSH-Px) activity (p < 0.05), reflecting enhanced antioxidant function. Gut morphology remained intact across all groups, indicating no adverse effects on intestinal barrier integrity. Microbiota analysis revealed significant increases (p < 0.05) in Firmicutes and Verrucomicrobiota abundance at the phylum level in the GOD-supplemented groups. Moreover, GOD treatments significantly increased the abundance of Faecalibacterium, Mucispirllum, and CHKCI001 at the genus level. Metabolic function predictions suggested that high-dose GOD supplementation enriched carbohydrate metabolism, particularly starch and sucrose metabolism. Correlation analysis indicated that Faecalibacterium and CHCKI001 were two bacteria strongly influenced by GOD supplementation and were associated with enhanced growth performance and improved gut health. In conclusion, high-dose GOD supplementation had no adverse effects and demonstrated significant benefits, promoting both growth performance and gut health in broilers.

Thymus spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells

The increasing incidence of colorectal cancer and inflammatory diseases poses a major health concern, with oxidative stress playing a significant role in the onset of these pathologies. Factors such as excessive consumption of sugar-rich and fatty foods, synthetic food additives, pesticides, alcohol, and tobacco contribute to oxidative stress and disrupt intestinal homeostasis. Functional foods arise as a potential tool to regulate redox balance in the intestinal tract. Herbs (such as Thymus spp.) have long been screened for their antioxidant properties, but their use as antioxidants for medicinal purposes requires validation in biological models. In this study, we addressed the potential antioxidant protection and preventive effects of extracts from two thyme species at the intestinal level, as well as their molecular mechanisms of action. Caco-2 cells were pre-exposed (4 h) to aqueous (AD) and hydroethanolic (HE) extracts of Thymus carnosus and Thymus capitellatus, followed by a recovery period in culture medium (16 h), and then treated with tert-butyl-hydroperoxide (TBHP; 4 h), before analyzing cell viability. The effect of the extracts' main components was also analysed. Cellular oxidative stress, cell-death markers, and the expression of antioxidant-related proteins were evaluated using flow cytometry on cells pre-exposed to the AD extracts and salvianolic acid A (SAA). Results showed that pre-exposure to AD extracts or SAA reduced TBHP-induced oxidative stress and cell death, mediated by increased levels of nuclear factor erythroid 2-related factor 2 (Nrf2) protein. The protective activity of T. capitellatus AD extract was shown to be dependent on NAD(P)H quinone dehydrogenase 1 (NQO1) protein expression and on increased glutathione (GSH) content. Furthermore, ursolic acid induced cytotoxicity and low cellular antioxidant activity, and thus the presence of this triterpenoid impaired the antioxidant effect of HE extracts. Thus, AD extracts show high potential as prophylactic dietary agents, while HE extracts arise as a source of nutraceuticals with antioxidant potential.

Protective Capacity of Helichrysum italicum Infusion Against Intestinal Barrier Disruption and Translocation of Salmonella Infantis

BACKGROUND

Helichrysum italicum is a Mediterranean plant with well-known anti-inflammatory activity, but our previous whole transcriptome analysis has found that H. italicum infusion (HII) can also affect cytoskeletal rearrangement and tight junctions. The goal of the present study was to determine if HII improves the intestinal barrier (IB) dysfunction and by what mechanism.

METHODS

Caco-2 cells on Transwell inserts were used as a model of IB permeability. Heat-killed (HKB) or live Salmonella Infantis bacteria were used to induce IB integrity disruption upon three different testing conditions: pre-, co-, and post-treatment with 0.2 v/v% HII. Transepithelial electrical resistance values were used as an indicator of monolayer integrity before and after all treatments, and RT-PCR was used to assess the expression of tight junction proteins (TJPs) and inflammatory cytokines known to regulate intestinal permeability.

RESULTS

We found that all three treatments with HII improved the HKB-induced integrity disruption and decreased the down-regulation of TJP1, OCLN, and CLDN1, with the greatest effect observed in the pre-treated cells. Treatment with HII also decreased the up-regulation of CLDN2, TNF-α, IL-1β, and IL-6. In addition, pre-treatment of Caco-2 cells with HII prevented translocation of S. Infantis but did not prevent adhesion and invasion.

CONCLUSION

This study showed that HII can improve inflammation-disrupted IB function by indirect modulation of mRNA expression of TJPs, especially in a preventive manner.

Solid-State Fermentation of Wheat Bran with Clostridium butyricum: Impact on Microstructure, Nutrient Release, Antioxidant Capacity, and Alleviation of Ulcerative Colitis in Mice

This study investigated the effects of solid-state fermentation with Clostridium butyricum on the microstructure of wheat bran, the release of dietary fiber and phenolic compounds, and antioxidant capacity. Compared with unfermented wheat bran, insoluble dietary fiber and phytic acid content decreased, whereas soluble dietary fiber and water-extractable arabinoxylan content increased in C. butyricum culture. Because of the increased release of phenolic compounds, such as ferulic acid and apigenin, and organic acids, such as isobutyric acid, the antioxidant capacity of the culture was considerably improved. Furthermore, the culture of C. butyricum treated with dextran sulfate sodium-induced ulcerative colitis in mice enhanced the expression of intestinal mucus and tight-junction proteins, modulating the gut microbiota structure, increasing the levels of short-chain fatty acids in the intestine, and restoring the essential functions of the gut microbiota. These anti-inflammatory effects stemmed from the combined action of various effective components.

Akkermania muciniphila: a rising star in tumor immunology

Tumor is accompanied by complex and dynamic microenvironment development, and the interaction of all its components influences disease progression and response to treatment. Once the tumor microenvironment has been eradicated, various mechanisms can induce the tumors. Microorganisms can maintain the homeostasis of the tumor microenvironment through immune regulation, thereby inhibiting tumor development. Akkermania muciniphila (A. muciniphila), an anaerobic bacterium, can induce tumor immunity, regulate the gastrointestinal microenvironment through metabolites, outer membrane proteins, and some cytokines, and enhance the curative effect through combined immunization. Therefore, a comprehensive understanding of the complex interaction between A. muciniphila and human immunity will facilitate the development of immunotherapeutic strategies in the future and enable patients to obtain a more stable clinical response. This article reviews the most recent developments in the tumor immunity of A. muciniphila.

Polygonatum sibiricum polysaccharide regulation of gut microbiota: A viable approach to alleviate cognitive impairment

Polygonatum sibiricum has anti-inflammatory effects and is one of the well-known functional foods. Polygonatum sibiricum polysaccharide (PSP), as a traditional medicinal and food homologous substance, can regulate the balance of intestinal flora and short chain fatty acid levels, reduce intestinal permeability and serum endotoxin levels, and inhibit the activation of astrocytes and microglia. It can significantly alleviate neurological diseases and improve cognitive impairment. Current evidence suggests that bidirectional communication between the central nervous system and the gastrointestinal tract may affect the human nervous system, cognition, and behavior through the gut-brain axis. This article provides a systematic review, detailing the biological activity of PSP, and explores the pathogenesis of gut microbiota signaling in cognitive impairment, providing a promising strategy for improving cognitive impairment.

Understanding the impact of the gut microbiome on opioid use disorder: Pathways, mechanisms, and treatment insights

The widespread use of opioids for chronic pain management not only poses a significant public health issue but also contributes to the risk of tolerance, dependence, and addiction, leading to opioid use disorder (OUD), which affects millions globally each year. Recent research has highlighted a potential bidirectional relationship between the gut microbiome and OUD. This emerging perspective is critical, especially as the opioid epidemic intensifies, emphasizing the need to investigate how OUD may alter gut microbiome dynamics and vice versa. Understanding these interactions could reveal new insights into the mechanisms of addiction and tolerance, as well as provide novel approaches for managing and potentially mitigating OUD impacts. This comprehensive review explores the intricate bidirectional link through the gut-brain axis, focusing on how opiates influence microbial composition, functional changes, and gut mucosal integrity. By synthesizing current findings, the review aims to inspire new strategies to combat the opioid crisis and leverage microbiome-centred interventions for preventing and treating OUD.

The role of the gut microbiota in neurodegenerative diseases targeting metabolism

In recent years, the incidence of neurodegenerative diseases (NDs) has gradually increased over the past decades due to the rapid aging of the global population. Traditional research has had difficulty explaining the relationship between its etiology and unhealthy lifestyle and diets. Emerging evidence had proved that the pathogenesis of neurodegenerative diseases may be related to changes of the gut microbiota's composition. Metabolism of gut microbiota has insidious and far-reaching effects on neurodegenerative diseases and provides new directions for disease intervention. Here, we delineated the basic relationship between gut microbiota and neurodegenerative diseases, highlighting the metabolism of gut microbiota in neurodegenerative diseases and also focusing on treatments for NDs based on gut microbiota. Our review may provide novel insights for neurodegeneration and approach a broadly applicable basis for the clinical therapies for neurodegenerative diseases.

The gut homeostasis-immune system axis: novel insights into rheumatoid arthritis pathogenesis and treatment

Rheumatoid arthritis is a widely prevalent autoimmune bone disease that imposes a significant burden on global healthcare systems due to its increasing incidence. In recent years, attention has focused on the interaction between gut homeostasis and the immune system, particularly in relation to bone health. Dysbiosis, which refers to an imbalance in the composition and function of the gut microbiota, has been shown to drive immune dysregulation through mechanisms such as the release of pro-inflammatory metabolites, increased gut permeability, and impaired regulatory T cell function. These factors collectively contribute to immune system imbalance, promoting the onset and progression of Rheumatoid arthritis. Dysbiosis induces both local and systemic inflammatory responses, activating key pro-inflammatory cytokines such as tumor necrosis factor-alpha, Interleukin-6, and Interleukin-17, which exacerbate joint inflammation and damage. Investigating the complex interactions between gut homeostasis and immune regulation in the context of Rheumatoid arthritis pathogenesis holds promise for identifying new therapeutic targets, revealing novel mechanisms of disease progression, and offering innovative strategies for clinical treatment.

The Consumption of the Fibrous Fraction of Solanum lycocarpum St. Hil. Does Not Preserve the Intestinal Mucosa in TNBS-Induced Rats

Solanum lycocarpum St. Hil. is considered a natural anti-inflammatory. In traditional medicine, it is used to reduce cholesterol levels in the treatment of obesity. Foods capable of conferring a protective and nutritious effect have been used to prevent or attenuate the clinical symptoms of inflammatory bowel diseases. Ulcerative colitis is a multifactorial inflammatory bowel disease. This study investigated the impact of the consumption of the fibrous fraction (FF) and resistant starch (RS) of fruta-do-lobo in an experimental model of colitis induced with the use 2,4,6-trinitrobenzene sulphonic acid (TNBS) in rats. The different colitis groups all experienced decreased weight gain, which could be linked to the inflammatory process (p = 0.603). Additionally, the experimental model led to increased oxidative stress, higher levels of pro-inflammatory cytokines, and the elevated gene expression of these cytokines. Despite this, consuming the fibrous fraction of fruta-do-lobo (RS and FF) did not appear to protect the animals against the inflammatory process. Regarding the expression of TNF-α, only the group treated with the drug mesalamine had a reduced serum level of this inflammatory marker (p = 0.03). Our results showed that the diet containing RS and FF did not protect the intestinal mucosa against TNBS inflammation. New studies on the variation in the time of consumption or the supplemented dose of fruta-do-lobo fibers could help to elucidate their effects in protecting the mucosa.

The effect of nerve cells on the intestinal barrier function and the influence of human milk oligosaccharides (hMOs) on the intestinal neuro-epithelial crosstalk

The intestinal epithelium is an important gatekeeper of the human body by forming a barrier for the luminal content of the intestine. The barrier function is regulated by a complex crosstalk between different cell types, including cells from the enteric nervous system (ENS). ENS is considered to influence gastrointestinal processes and functions, but its direct effect on epithelial barrier function remains to be confirmed. To investigate the effect of nerve cells on the gut barrier function, an in vitro co-culture system was established in which T84 intestinal epithelial cells and SH-SY5Y nerve cells were seeded in ratios of 29:1 and 14:1. When the epithelial barrier was disrupted with the calcium ionophores A23187, we found that nerve cells exert a protective effect on A23187-induced disruption and that this protective effect is nerve cell concentration-dependent. This was demonstrated by rescuing effects on transepithelial electrical resistance (TEER) and upregulation of tight junction (TJ) protein expression. Furthermore, we studied whether similar rescuing effects could be achieved with the human milk oligosaccharides (hMOs) 2'-fucosyllactose (2'-FL) and 3-fucosyllactose (3-FL). Our results illustrate that in the presence of nerve cells 2'-FL and 3-FL do not have any additional rescuing effects, but that these hMOs can substitute the rescuing effects of nerve cells in the absence of nerve cells. Meanwhile, 2'-FL and 3-FL show different regulation effects on TJ expression. These findings provide valuable insights into potential therapeutic strategies for maintaining intestinal barrier integrity.

Utilizing pigs as a model for studying intestinal barrier function

Intestinal permeability has been extensively studied, particularly in gastrointestinal diseases such as inflammatory bowel disease, food allergy, visceral disease, celiac disease, and Crohn’s disease. These studies have established that changes in intestinal permeability contribute to the pathogenesis of many gastrointestinal and systemic diseases. While numerous works in the 20th century focused on this topic, it remains relevant for several reasons. Despite the development of new research techniques, it is still unclear whether changes in intestinal permeability are the primary mechanism initiating the disease process or if they occur secondary to an ongoing chronic inflammatory process. Investigating the possibility of stabilizing the intestinal barrier, thereby reducing its permeability preemptively to prevent damage and after the damage has occurred, may offer new therapeutic approaches. Increased intestinal permeability is believed to lead to reduced nutrient absorption, resulting in decreased immunity and production of digestive enzymes.

Yellow Teas Protect against DSS-Induced Ulcerative Colitis by Inhibiting TLR4/NF-κB/NLRP3 Inflammasome in Mice

Yellow tea (YT), a slightly fermented tea with a unique yellowing process and mellow taste, is becoming widely popular. Currently, the YT includes bud yellow tea (BYT), small-leaf yellow tea (SYT), and large-leaf yellow tea (LYT) based on maturity of raw materials. Previous studies have shown that YT has outstanding potential in preventing metabolic syndrome. However, the distinct effects and mechanisms of different types of YT on ulcerative colitis (UC) are still unclear. This study investigated the effects and mechanisms of continuous or intermittent intervention of three yellow tea water extracts (YTEs) on dextran sulfate sodium (DSS)-induced ulcerative colitis in CD-1 mice. The results showed that YTE intervention significantly improves the syndrome of DSS-induced UC in mice. Mechanistic studies reveal that YTEs increase the expression levels of tight junction (TJ) proteins and reduce the levels of pro-inflammatory cytokines in the colon by inactivating TLR4/NF-κB/NLRP3. YTE treatment protected intestinal barrier integrity and reduced serum lipopolysaccharide (LPS) levels. Interestingly, our results indicate that large-leaf yellow tea (LYT) has a better alleviating effect than BYT and SYT. YTE intervention before DSS administration has a certain degree of preventive effect on ulcerative colitis, while continuous YTE intervention after DSS induction has a significant reversing effect on the damage caused by DSS. Our results indicated that drinking YT may have preventive and therapeutic effect on UC, especially drinking LYT.

Structure-dependent capacity of procyanidin dimers to inhibit inflammation-induced barrier dysfunction in a cell model of intestinal epithelium

Diet is of major importance in modulating intestinal inflammation, as the gastrointestinal tract is directly exposed to high concentrations of dietary components. Procyanidins are flavan-3-ol oligomers abundant in fruits and vegetables. Although with limited or no intestinal absorption, they can have GI health benefits which can promote overall health. We previously observed that epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) dimers inhibit in vitro colorectal cancer cell proliferation and invasiveness. Inflammation-mediated intestinal barrier permeabilization can result in a chronic inflammatory condition and promote colorectal cancer onset/progression. Thus, this study investigated the structure-dependent capacity of ECG, EGCG and (-)-epicatechin (EC) dimers to inhibit tumor necrosis factor alpha (TNFα)-induced inflammation, oxidative stress, and loss of barrier integrity in Caco-2 cells differentiated into an intestinal epithelial cell monolayer. Cells were incubated with TNFα (10 ng/ml), in the absence/presence of ECG, EGCG and EC dimers. The three dimers inhibited TNFα-mediated Caco-2 cell monolayer permeabilization, modulating events involved in the loss of barrier function and inflammation, i.e. decreased tight junction protein levels; increased matrix metalloproteinases expression and activity; increased NADPH oxidase expression and oxidant production; activation of the NF-κB and ERK1/2 pathways and downstream events leading to tight junction opening. For some of these mechanisms, the galloylated ECG and EGCG dimers had stronger protective potency than the non-galloylated EC dimer. These differences could be due to differential membrane interactions as pointed out by molecular dynamics simulation of procyanidin dimers-cell membrane interactions and/or by differential interactions with NOX1. Results show that dimeric procyanidins, although poorly absorbed, can promote health by alleviating intestinal inflammation, oxidative stress and barrier permeabilization.

The potential of orally exposed risk factors and constituents aggravating food allergy: Possible mechanism and target cells

Food allergy is a significant concern for the health of humans worldwide. In addition to dietary exposure of food allergens, genetic and environmental factors also play an important role in the development of food allergy. However, only the tip of the iceberg of risk factors in food allergy has been identified. The importance of food allergy caused by orally exposed risk factors and constituents, including veterinary drugs, pesticides, processed foods/derivatives, nanoparticles, microplastics, pathogens, toxins, food additives, dietary intake of salt/sugar/total fat, vitamin D, and therapeutic drugs, are highlighted and discussed in this review. Moreover, the epithelial barrier hypothesis, which is closely associated with the occurrence of food allergy, is also introduced. Additionally, several orally exposed risk factors and constituents that have been reported to disrupt the epithelial barrier are elucidated. Finally, the possible mechanisms and key immune cells of orally exposed risk factors and constituents in aggravating food allergy are overviewed. Further work should be conducted to define the specific mechanism by which these risk factors and constituents are driving food allergy, which will be of central importance to the targeted therapy of food allergy.

Influence of human gut microbiome on the healthy and the neurodegenerative aging

The gut microbiome plays a crucial role in host health throughout the lifespan by influencing brain function during aging. The microbial diversity of the human gut microbiome decreases during the aging process and, as a consequence, several mechanisms increase, such as oxidative stress, mitochondrial dysfunction, inflammatory response, and microbial gut dysbiosis. Moreover, evidence indicates that aging and neurodegeneration are closely related; consequently, the gut microbiome may serve as a novel marker of lifespan in the elderly. In this narrative study, we investigated how the changes in the composition of the gut microbiome that occur in aging influence to various neuropathological disorders, such as mild cognitive impairment (MCI), dementia, Alzheimer's disease (AD), and Parkinson's disease (PD); and which are the possible mechanisms that govern the relationship between the gut microbiome and cognitive impairment. In addition, several studies suggest that the gut microbiome may be a potential novel target to improve hallmarks of brain aging and to promote healthy cognition; therefore, current and future therapeutic interventions have been also reviewed.

Emerging Trends in the Application of Extracellular Vesicles as Novel Oral Delivery Vehicles for Therapeutics in Inflammatory Diseases

Inflammation involves complex immune responses where cytokines such as TNF-α, IL-1, and IL-6 promote vasodilation and increased vascular permeability to facilitate immune cell migration to inflammation sites. Persistent inflammation is linked to diseases like cancer, arthritis, and neurodegenerative disorders. Although oral anti-inflammatory drugs are favored for their non-invasiveness and cost-effectiveness, their efficacy is often compromised due to gastrointestinal degradation and limited bioavailability. Recent advancements highlight the potential of extracellular vesicles (EVs) as nanocarriers that enhance drug delivery by encapsulating therapeutic agents, ensuring targeted release and reduced toxicity. These EVs, derived from dietary sources and cell cultures, exhibit excellent biocompatibility and stability, presenting a novel approach in anti-inflammatory therapies. This review discusses the classification and advantages of orally administered EVs (O-EVs), their mechanism of action, and their emerging role in treating inflammatory conditions, positioning them as promising vectors in the development of innovative anti-inflammatory drug delivery systems.

Gut Microbiota in the Progression of Type 2 Diabetes and the Potential Role of Exercise: A Critical Review

Type 2 diabetes (T2D) is the predominant metabolic epidemic posing a major threat to global health. Growing evidence indicates that gut microbiota (GM) may critically influence the progression from normal glucose tolerance, to pre-diabetes, to T2D. On the other hand, regular exercise contributes to the prevention and/or treatment of the disease, and evidence suggests that a possible way regular exercise favorably affects T2D is by altering GM composition toward health-promoting bacteria. However, research regarding this potential effect of exercise-induced changes of GM on T2D and the associated mechanisms through which these effects are accomplished is limited. This review presents current data regarding the association of GM composition and T2D and the possible critical GM differentiation in the progression from normal glucose, to pre-diabetes, to T2D. Additionally, potential mechanisms through which GM may affect T2D are presented. The effect of exercise on GM composition and function on T2D progression is also discussed.

Postoperative delayed gastric emptying: may gut microbiota play a role?

Postoperative delayed gastric emptying is a prevalent complication following surgical procedures, imposing heavy physical and financial burdens on patients. However, current treatment options remain suboptimal. In recent years, an increasing number of studies have highlighted that the gut microbiota and its metabolites are closely associated with postoperative complications. Various factors can disrupt the gut microbiome after surgery. This review discusses the potential mechanisms by which the gut microbiota and their metabolites may contribute to the pathogenesis of postoperative delayed gastric emptying. However, the current knowledge base is limited in terms of fully understanding the exact mechanisms involved. It is therefore evident that further research is required to fully elucidate the role of the gut microbiome in postoperative delayed gastric emptying, with the aim of uncovering new possibilities for preventive measures and therapeutic treatments.

Patient-derived organoid biobank identifies epigenetic dysregulation of intestinal epithelial MHC-I as a novel mechanism in severe Crohn's Disease

OBJECTIVE

Epigenetic mechanisms, including DNA methylation (DNAm), have been proposed to play a key role in Crohn's disease (CD) pathogenesis. However, the specific cell types and pathways affected as well as their potential impact on disease phenotype and outcome remain unknown. We set out to investigate the role of intestinal epithelial DNAm in CD pathogenesis.

DESIGN

We generated 312 intestinal epithelial organoids (IEOs) from mucosal biopsies of 168 patients with CD (n=72), UC (n=23) and healthy controls (n=73). We performed genome-wide molecular profiling including DNAm, bulk as well as single-cell RNA sequencing. Organoids were subjected to gene editing and the functional consequences of DNAm changes evaluated using an organoid-lymphocyte coculture and a nucleotide-binding oligomerisation domain, leucine-rich repeat and CARD domain containing 5 (NLRC5) dextran sulphate sodium (DSS) colitis knock-out mouse model.

RESULTS

We identified highly stable, CD-associated loss of DNAm at major histocompatibility complex (MHC) class 1 loci including NLRC5 and cognate gene upregulation. Single-cell RNA sequencing of primary mucosal tissue and IEOs confirmed the role of NLRC5 as transcriptional transactivator in the intestinal epithelium. Increased mucosal MHC-I and NLRC5 expression in adult and paediatric patients with CD was validated in additional cohorts and the functional role of MHC-I highlighted by demonstrating a relative protection from DSS-mediated mucosal inflammation in NLRC5-deficient mice. MHC-I DNAm in IEOs showed a significant correlation with CD disease phenotype and outcomes. Application of machine learning approaches enabled the development of a disease prognostic epigenetic molecular signature.

CONCLUSIONS

Our study has identified epigenetically regulated intestinal epithelial MHC-I as a novel mechanism in CD pathogenesis.

Xuanbi Yuyang Decoction Ameliorates DSS-Induced Colitis by Inhibiting Pyroptosis via Blocking of IL-17 Pathway Activation

Background

Ulcerative colitis (UC), a highly relapsing non-specific disease, is difficult to cure completely. The investigation aims to determine the protective effect and potential action mechanism of Xuanbi yuyang decoction (XBD) on UC.

Methods

The chemical composition of XBD was determined through non-targeted metabolomics analysis. Subsequently, experimental mice were orally given 3% DSS for 6 days, followed by XBD treatment (0.3 mL, 0.4 mL). In vitro, the human colon epithelial cells were co-treated with DSS and medicated serum. The therapeutic effects of XBD on UC were evaluated in vivo and vitro. The mechanisms of XBD against UC were determined by detecting hallmarks related to pyroptosis and Interleukin (IL)-17 pathways using Western blot and ELISA. The recombinant human interleukin 17A (rhIL17A) and was applied for further verifying the effect of XBD on IL-17 pathway in UC cells.

Results

XBD supplementation restored DSS-induced weight loss, colon shortening and tissue damage, and reduced DAI. Moreover, XBD enhanced viability, repaired the intestinal mucosal barrier of colitis, decreased pro-inflammatory cytokines levels, and inhibited pyroptosis. Additionally, DSS increased the expression of IL-17 pathway was and cytokines (IL-17A, IL-6), which were blocked by XBD treatment. The rhIL17A treatment attenuated protective effect against DSS-induced colitis and could also enhance pyroptosis.

Conclusion

XBD has a favorable protective effect against DSS-induced colitis through restraining pyroptosis via inhibition of IL-17 signaling pathway activation, suggesting XBD may be a new and effective treatment therapy for UC.

High-altitude hypoxia promotes BRD4-mediated activation of the Wnt/β-catenin pathway and disruption of intestinal barrier

Hypobaric hypoxia, commonly experienced at elevated altitudes, presents significant physiological challenges. Our investigation is centered on the impact of the bromodomain protein 4 (BRD4) under these conditions, especially its interaction with the Wnt/β-Catenin pathway and resultant effects on glycolytic inflammation and intestinal barrier stability. By combining transcriptome sequencing with bioinformatics, we identified BRD4's key role in hypoxia-related intestinal anomalies. Clinical parameters of altitude sickness patients, including serum BRD4 levels, inflammatory markers, and barrier integrity metrics, were scrutinized. In vitro studies using CCD 841 CoN cells depicted expression changes in BRD4, Interleukin (IL)-1β, IL-6, and β-Catenin. Transepithelial electrical resistance (TEER) and FD4 analyses assessed barrier resilience. Hypoxia-induced mouse models, analyzed via H&E staining and Western blot, provided insights into barrier and protein alterations. Under hypoxic conditions, marked BRD4 expression variations emerged. Elevated serum BRD4 in patients coincided with intensified Wnt signaling, inflammation, and barrier deterioration. In vitro, findings showed hypoxia-induced upregulation of BRD4 and inflammatory markers but a decline in Occludin and ZO1, affecting barrier strength-effects mitigated by BRD4 inhibition. Mouse models echoed these patterns, linking BRD4 upregulation in hypoxia to barrier perturbations. Hypobaric hypoxia-induced BRD4 upregulation disrupts the Wnt/β-Catenin signaling, sparking glycolysis-fueled inflammation and weakening intestinal tight junctions and barrier degradation.

Dietary Polycan, a β-glucan originating from Aureobasidium pullulansSM-2001, attenuates high-fat-diet-induced intestinal barrier damage in obese mice by modulating gut microbiota dysbiosis

Various metabolic diseases caused by a high-fat diet (HFD) are closely related to gut microbiota dysbiosis and epithelial barrier dysfunction. Polycan, a type of β-glucan, is effective in treating anti-obesity and metabolic diseases caused by HFD. However, the effect of Polycan on dysbiosis and epithelial barrier damage is still unknown. In this study, the effects of Polycan on dysbiosis and intestinal barrier damage were investigated using HFD-induced obese model mice. C57BL/6 mice were fed a HFD for 12 weeks and treated with two different doses of Polycan (250 and 500 mg/kg) orally administered during weeks 9 to 12. Polycan supplementation increased the expression of tight junction genes (zonula occludens-1, occludin, and claudin-3) and short-chain fatty acid (SCFA) content while reducing toxic substances (phenol, p-cresol, and skatole). Most significantly, Polycan enriched SCFA-producing bacteria (i.e., Phocaeicola, Bacteroides, Faecalibaculum, Oscillibacter, Lachnospiraceae, and Muribaculaceae), and decreased the Firmicutes/Bacteroidetes ratio and toxic substances-producing bacteria (i.e., Olsenella, Clostridium XVIII, and Schaedlerella). Furthermore, microbial functional capacity prediction of the gut microbiota revealed that Polycan enriched many SCFA-related KEGG enzymes while toxic substance-related KEGG enzymes were depleted. These findings indicated that Polycan has the potential to alleviate HFD-induced intestinal barrier damage by modulating the function and composition of the gut microbiota.

Development of Delivery Systems with Prebiotic and Neuroprotective Potential of Industrial-Grade Cannabis sativa L

This study delves into the transformative effects of supercritical carbon dioxide (scCO2) cannabis extracts and prebiotic substances (dextran, inulin, trehalose) on gut bacteria, coupled with a focus on neuroprotection. Extracts derived from the Białobrzeska variety of Cannabis sativa, utilising supercritical fluid extraction (SFE), resulted in notable cannabinoid concentrations (cannabidiol (CBD): 6.675 ± 0.166; tetrahydrocannabinol (THC): 0.180 ± 0.006; cannabigerol (CBG): 0.434 ± 0.014; cannabichromene (CBC): 0.490 ± 0.017; cannabinol (CBN): 1.696 ± 0.047 mg/gD). The assessment encompassed antioxidant activity via four in vitro assays and neuroprotective effects against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The extract boasting the highest cannabinoid content exhibited remarkable antioxidant potential and significant inhibitory activity against both enzymes. Further investigation into prebiotic deliveries revealed their proficiency in fostering the growth of beneficial gut bacteria while maintaining antioxidant and neuroprotective functionalities. This study sheds light on the active compounds present in the Białobrzeska variety, showcasing their therapeutic potential within prebiotic systems. Notably, the antioxidant, neuroprotective, and prebiotic properties observed underscore the promising therapeutic applications of these extracts. The results offer valuable insights for potential interventions in antioxidant, neuroprotective, and prebiotic domains. In addition, subsequent analyses of cannabinoid concentrations post-cultivation revealed nuanced changes, emphasising the need for further exploration into the dynamic interactions between cannabinoids and the gut microbiota.

Mechanism of Salvia miltiorrhiza Bunge extract to alleviate Chronic Sleep Deprivation-Induced cognitive dysfunction in rats

BACKGROUND

Bidirectional communication between the gut microbiota and the brain may play an essential role in the cognitive dysfunction associated with chronic sleep deprivation(CSD). Salvia miltiorrhiza Bunge (Danshen, DS), a famous Chinese medicine and functional tea, is extensively used to protect learning and memory capacities, although the mechanism of action remains unknown.

PURPOSE

The purpose of this research was to explore the efficacy and the underlying mechanism of DS in cognitive dysfunction caused by CSD.

METHODS

DS chemical composition was analyzed by UPLC-QTOF-MS/MS. Forty rats were randomly assigned to five groups (n = 8): control (CON), model (MOD), low- (1.35 g/kg, DSL), high-dose (2.70 g/kg, DSH) DS group, and Melatonin(100 mg/kg, MT) group. A CSD rat model was established over 21 days. DS's effects and the underlying mechanism were explored using the open-field test(OFT), Morris water-maze(MWM), tissue staining(Hematoxylin and Eosin Staining, Nissl staining, Alcian blue-periodic acid SCHIFF staining, and Immunofluorescence), enzyme-linked immunosorbent assay, Western blot, quantitative real-time polymerase chain reaction(qPCR), and 16S rRNA sequencing.

RESULTS

We demonstrated that CSD caused gut dysbiosis and cognitive dysfunction. Furthermore, 16S rRNA sequencing demonstrated that Firmicutes and Proteobacteria were more in fecal samples from model group rats, whereas Bacteroidota and Spirochaetota were less. DS therapy, on the contrary hand, greatly restored the gut microbial community, consequently alleviating cognitive impairment in rats. Further research revealed that DS administration reduced systemic inflammation via lowering intestinal inflammation and barrier disruption. Following that, DS therapy reduced Blood Brain Barrier(BBB) and neuronal damage, further decreasing neuroinflammation in the hippocampus(HP). Mechanistic studies revealed that DS therapy lowered lipopolysaccharide (LPS) levels in the HP, serum, and colon, consequently blocking the TLR4/MyD88/NF-κB signaling pathway and its downstream pro-inflammatory products(IL-1β, IL-6, TNF-α, iNOS, and COX2) in the HP and colon.

CONCLUSION

DS treatment dramatically improved spatial learning and memory impairments in rats with CSD by regulating the composition of the intestinal flora, preserving gut and brain barrier function, and reducing inflammation mediated by the LPS-TLR4 signaling pathway. Our findings provide novel insight into the mechanisms by which DS treats cognitive dysfunction caused by CSD.

Contemporary Perspectives on the Role of Vitamin D in Enhancing Gut Health and Its Implications for Preventing and Managing Intestinal Diseases

Vitamin D, a crucial fat-soluble vitamin, is primarily synthesized in the skin upon exposure to ultraviolet radiation and is widely recognized as a bone-associated hormone. However, recent scientific advancements have unveiled its intricate association with gut health. The intestinal barrier serves as a vital component, safeguarding the intestinal milieu and maintaining overall homeostasis. Deficiencies in vitamin D have been implicated in altering the gut microbiome composition, compromising the integrity of the intestinal mucosal barrier, and predisposing individuals to various intestinal pathologies. Vitamin D exerts its regulatory function by binding to vitamin D receptors (VDR) present in immune cells, thereby modulating the production of pro-inflammatory cytokines and influencing the intestinal barrier function. Notably, numerous studies have reported lower serum vitamin D levels among patients suffering from intestinal diseases, including inflammatory bowel disease, irritable bowel syndrome, and celiac disease, highlighting the growing significance of vitamin D in gut health maintenance. This comprehensive review delves into the latest advancements in understanding the mechanistic role of vitamin D in modulating the gut microbiome and intestinal barrier function, emphasizing its pivotal role in immune regulation. Furthermore, we consolidate and present relevant findings pertaining to the therapeutic potential of vitamin D in the management of intestinal diseases.