Quercetin Alleviates Insulin Resistance and Repairs Intestinal Barrier in db/db Mice by Modulating Gut Microbiota.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease which seriously affects public health. Gut microbiota remains a dynamic balance state in healthy individuals, and its disorder may affect health status and even results in metabolic diseases. Quercetin, a natural flavonoid, has been shown to have biological activities that can be used in the prevention and treatment of metabolic diseases. This study aimed to explore the mechanism of quercetin in alleviating T2DM based on gut microbiota. db/db mice were adopted as the model for T2DM in this study. After 10 weeks of administration, quercetin could significantly decrease the levels of body weight, fasting blood glucose (FBG), serum insulin (INS), the homeostasis model assessment of insulin resistance (HOMA-IR), monocyte chemoattractant protein-1 (MCP-1), D-lactic acid (D-LA), and lipopolysaccharide (LPS) in db/db mice. 16S rRNA gene sequencing and untargeted metabolomics analysis were performed to compare the differences of gut microbiota and metabolites among the groups. The results demonstrated that quercetin decreased the abundance of Proteobacteria, Bacteroides, Escherichia-Shigella and Escherichia_coli. Moreover, metabolomics analysis showed that the levels of L-Dopa and S-Adenosyl-L-methionine (SAM) were significantly increased, but 3-Methoxytyramine (3-MET), L-Aspartic acid, L-Glutamic acid, and Androstenedione were significantly decreased under quercetin intervention. Taken together, quercetin could exert its hypoglycemic effect, alleviate insulin resistance, repair the intestinal barrier, remodel the intestinal microbiota, and alter the metabolites of db/db mice.

Can Diet Alter the Intestinal Barrier Permeability in Healthy People? A Systematic Review.

Dietary factors can modify the function of the intestinal barrier, causing permeability changes. This systematic review analyzed evidence on the link between diet or dietary interventions and changes in intestinal barrier permeability (IBP) in healthy individuals. A systematic search for primary studies was conducted using the virtual databases EMBASE, PubMed, Web of Science, CINAHL, and Scopus. This review adhered to PRISMA 2020 guidelines, assessing the methodological quality using the Newcastle-Ottawa scale for observational studies and ROB 2.0 for randomized clinical trials. Out of 3725 studies recovered, 12 were eligible for review. Chicory inulin and probiotics reduced IBP in adults with a moderate GRADE level of evidence. The opposite result was obtained with fructose, which increased IBP in adults, with a very low GRADE level of evidence. Only intervention studies with different dietary components were found, and few studies evaluated the effect of specific diets on the IBP. Thus, there was no strong evidence that diet or dietary interventions increase or decrease IBP in healthy individuals. Studies on this topic are necessary, with a low risk of bias and good quality of evidence generated, as there is still little knowledge on healthy populations.

How the Microbiota May Affect Celiac Disease and What We Can Do.

Celiac disease (CeD) is an autoimmune disease with a strong association with human leukocyte antigen (HLA), characterized by the production of specific autoantibodies and immune-mediated enterocyte killing. CeD is a unique autoimmune condition, as it is the only one in which the environmental trigger is known: gluten, a storage protein present in wheat, barley, and rye. How and when the loss of tolerance of the intestinal mucosa to gluten occurs is still unknown. This event, through the activation of adaptive immune responses, enhances epithelial cell death, increases the permeability of the epithelial barrier, and induces secretion of pro-inflammatory cytokines, resulting in the transition from genetic predisposition to the actual onset of the disease. While the role of gastrointestinal infections as a possible trigger has been considered on the basis of a possible mechanism of antigen mimicry, a more likely alternative mechanism appears to involve a complex disruption of the gastrointestinal microbiota ecosystem triggered by infections, rather than the specific effect of a single pathogen on intestinal mucosal homeostasis. Several lines of evidence show the existence of intestinal dysbiosis that precedes the onset of CeD in genetically at-risk subjects, characterized by the loss of protective bacterial elements that both epigenetically and functionally can influence the response of the intestinal epithelium leading to the loss of gluten tolerance. We have conducted a literature review in order to summarize the current knowledge about the complex and in part still unraveled dysbiosis that precedes and accompanies CeD and present some exciting new data on how this dysbiosis might be prevented and/or counteracted. The literature search was conducted on PubMed.gov in the time frame 2010 to March 2024 utilizing the terms "celiac disease and microbiota", "celiac disease and microbiome", and "celiac disease and probiotics" and restricting the search to the following article types: Clinical Trials, Meta-Analysis, Review, and Systematic Review. A total of 364 papers were identified and reviewed. The main conclusions of this review can be outlined as follows: (1) quantitative and qualitative changes in gut microbiota have been clearly documented in CeD patients; (2) intestinal microbiota's extensive and variable interactions with enterocytes, viral and bacterial pathogens and even gluten combine to impact the inflammatory immune response to gluten and the loss of gluten tolerance, ultimately affecting the pathogenesis, progression, and clinical expression of CeD; (3) gluten-free diet fails to restore the eubiosis of the digestive tract in CeD patients, and also negatively affects microbial homeostasis; (4) new tools allowing targeted microbiota therapy, such as the use of probiotics (a good example being precision probiotics like the novel strain of B. vulgatus (20220303-A2) begin to show exciting potential applications.

Slit2-Robo4 signal pathway and tight junction in intestine mediate LPS-induced inflammation in mice.

BACKGROUND: Sepsis is one of the most common clinical diseases, which is characterized by a serious and uncontrollable inflammatory response. LPS-induced inflammation is a critical pathological event in sepsis, but the underlying mechanism has not yet been fully elucidated. METHODS: The animal model was established for two batches. In the first batch of experiments, Adult C57BL/6J mice were randomly divided into control group and LPS (5 mg/kg, i.p.)group . In the second batch of experiments, mice were randomly divided into control group, LPS group, and LPS+VX765(10 mg/kg, i.p., an inhibitor of NLRP3 inflammasome) group. After 24 hours, mice were anesthetized with isoflurane, blood and intestinal tissue were collected for tissue immunohistochemistry, Western blot analysis and ELISA assays. RESULTS: The C57BL/6J mice injected with LPS for twenty-four hours could exhibit severe inflammatory reaction including an increased IL-1ß, IL-18 in serum and activation of NLRP3 inflammasome in intestine. The injection of VX765 could reverse these effects induced by LPS. These results indicated that the increased level of IL-1ß and IL-18 in serum induced by LPS is related to the increased intestinal permeability and activation of NLRP3 inflammasome. In the second batch of experiments, results of western blot and immunohistochemistry showed that Slit2 and Robo4 were significant decreased in intestine of LPS group, while the expression of VEGF was significant increased. Meanwhile, the protein level of tight junction protein ZO-1, occludin, and claudin-5 were significantly lower than in control group, which could also be reversed by VX765 injection. CONCLUSIONS: In this study, we revealed that Slit2-Robo4 signaling pathway and tight junction in intestine may be involved in LPS-induced inflammation in mice, which may account for the molecular mechanism of sepsis.

Effects of Scallop Mantle Toxin on Intestinal Microflora and Intestinal Barrier Function in Mice.

Previous studies have shown that feeding mice with food containing mantle tissue from Japanese scallops results in aggravated liver and kidney damage, ultimately resulting in mortality within weeks. The aim of this study is to evaluate the toxicity of scallop mantle in China's coastal areas and explore the impact of scallop mantle toxins (SMT) on intestinal barrier integrity and gut microbiota in mice. The Illumina MiSeq sequencing of V3-V4 hypervariable regions of 16S ribosomal RNA was employed to study the alterations in gut microbiota in the feces of SMT mice. The results showed that intestinal flora abundance and diversity in the SMT group were decreased. Compared with the control group, significant increases were observed in serum indexes related to liver, intestine, inflammation, and kidney functions among SMT-exposed mice. Accompanied by varying degrees of tissue damage observed within these organs, the beneficial bacteria of Muribaculaceae and Marinifilaceae significantly reduced, while the harmful bacteria of Enterobacteriaceae and Helicobacter were significantly increased. Taken together, this article elucidates the inflammation and glucose metabolism disorder caused by scallop mantle toxin in mice from the angle of gut microbiota and metabolism. SMT can destroy the equilibrium of intestinal flora and damage the intestinal mucosal barrier, which leads to glucose metabolism disorder and intestinal dysfunction and may ultimately bring about systemic toxicity.

Intestinal mRNA expression profiles associated with mucosal healing in ustekinumab-treated Crohn's disease patients: bioinformatics analysis and prospective cohort validation.

BACKGROUND: Variations exist in the response of patients with Crohn's disease (CD) to ustekinumab (UST) treatment, but the underlying cause remains unknown. Our objective was to investigate the involvement of immune cells and identify potential biomarkers that could predict the response to interleukin (IL) 12/23 inhibitors in patients with CD. METHODS: The GSE207022 dataset, which consisted of 54 non-responders and 9 responders to UST in a CD cohort, was analyzed. Differentially expressed genes (DEGs) were identified and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Least absolute shrinkage and selection operator (LASSO) regression was used to screen the most powerful hub genes. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive performances of these genes. Single-sample Gene Set Enrichment Analysis (ssGSEA) was used to estimate the proportions of immune cell types. These significantly altered genes were subjected to cluster analysis into immune cell-related infiltration. To validate the reliability of the candidates, patients prescribed UST as a first-line biologic in a prospective cohort were included as an independent validation dataset. RESULTS: A total of 99 DEGs were identified in the integrated dataset. GO and KEGG analyses revealed significant enrichment of immune response pathways in patients with CD. Thirteen genes (SOCS3, CD55, KDM5D, IGFBP5, LCN2, SLC15A1, XPNPEP2, HLA-DQA2, HMGCS2, DDX3Y, ITGB2, CDKN2B and HLA-DQA1), which were primarily associated with the response versus nonresponse patients, were identified and included in the LASSO analysis. These genes accurately predicted treatment response, with an area under the curve (AUC) of 0.938. T helper cell type 1 (Th1) cell polarization was comparatively strong in nonresponse individuals. Positive connections were observed between Th1 cells and the LCN2 and KDM5D genes. Furthermore, we employed an independent validation dataset and early experimental verification to validate the LCN2 and KDM5D genes as effective predictive markers. CONCLUSIONS: Th1 cell polarization is an important cause of nonresponse to UST therapy in patients with CD. LCN2 and KDM5D can be used as predictive markers to effectively identify nonresponse patients. TRIAL REGISTRATION: Trial registration number: NCT05542459; Date of registration: 2022-09-14; URL: https://www. CLINICALTRIALS: gov .

Acute and Long COVID Intestinal Changes in an Experimental Model of Coronavirus in Mice.

The COVID-19 pandemic, which emerged in early 2020, has had a profound and lasting impact on global health, resulting in over 7.0 million deaths and persistent challenges. In addition to acute concerns, there is growing attention being given to the long COVID health consequences for survivors of COVID-19 with documented cases of cardiovascular abnormalities, liver disturbances, lung complications, kidney issues, and noticeable cognitive deficits. Recent studies have investigated the physiological changes in various organs following prolonged exposure to murine hepatitis virus-1 (MHV-1), a coronavirus, in mouse models. One significant finding relates to the effects on the gastrointestinal tract, an area previously understudied regarding the long-lasting effects of COVID-19. This research sheds light on important observations in the intestines during both the acute and the prolonged phases following MHV-1 infection, which parallel specific changes seen in humans after exposure to SARS-CoV-2. Our study investigates the histopathological alterations in the small intestine following MHV-1 infection in murine models, revealing significant changes reminiscent of inflammatory bowel disease (IBD), celiac disease. Notable findings include mucosal inflammation, lymphoid hyperplasia, goblet cell hyperplasia, and immune cell infiltration, mirroring pathological features observed in IBD. Additionally, MHV-1 infection induces villous atrophy, altered epithelial integrity, and inflammatory responses akin to celiac disease and IBD. SPIKENET (SPK) treatment effectively mitigates intestinal damage caused by MHV-1 infection, restoring tissue architecture and ameliorating inflammatory responses. Furthermore, investigation into long COVID reveals intricate inflammatory profiles, highlighting the potential of SPK to modulate intestinal responses and restore tissue homeostasis. Understanding these histopathological alterations provides valuable insights into the pathogenesis of COVID-induced gastrointestinal complications and informs the development of targeted therapeutic strategies.

Total flavonoids of Chrysanthemum indicum L inhibit colonic barrier injury induced by acute pancreatitis by affecting gut microorganisms.

BACKGROUND: Acute pancreatitis (AP) is a prevalent acute abdominal condition, and AP induced colonic barrier dysfunction is commonly observed. Total flavonoids of Chrysanthemum indicum L (TFC) have exhibited noteworthy anti-inflammatory and anti-apoptotic properties. METHODS: We established AP models, both in animals and cell cultures, employing Cerulein. 16S rRNA gene sequencing was performed to investigate the gut microorganisms changes. RESULTS: In vivo, TFC demonstrated a remarkable capacity to ameliorate AP, as indicated by the inhibition of serum amylase, myeloperoxidase (MPO) levels, and the reduction in pancreatic tissue water content. Furthermore, TFC effectively curtailed the heightened inflammatory response. The dysfunction of colonic barrier induced by AP was suppressed by TFC. At the in vitro level, TFC treatment resulted in attenuation of increased cell apoptosis, and regulation of apoptosis related proteins expression in AR42J cells. The increase of Bacteroides sartorial, Lactobacillus reuteri, Muribaculum intestinale, and Parabacteroides merdae by AP, and decrease of of Helicobacter rodentium, Pasteurellaceae bacterium, Streptococcus hyointestinalis by AP were both reversed by TFC treatment. CONCLUSIONS: TFC can effectively suppress AP progression and AP induced colonic barrier dysfunction by mitigating elevated serum amylase, MPO levels, water content in pancreatic tissue, as well as curtailing inflammation, apoptosis. The findings presented herein shed light on the potential mechanisms by which TFC inhibit the development of AP progression and AP induced colonic barrier dysfunction.

ACE2 mediates tryptophan alleviation on diarrhea by repairing intestine barrier involved mTOR pathway.

The membrane-delimited receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), angiotensin-converting enzyme 2 (ACE2), which is expressed in the intestine, collaborates with broad neutral amino acid transporter 1 (B0AT1). Tryptophan (Trp) is transported into intestinal epithelial cells by ACE2 and B0AT1. However, whether ACE2 and its binding protein B0AT1 are involved in Trp-mediated alleviation of intestinal injury is largely unknown. Here, we used weaned piglets and IPEC-J2 cells as models and found that ACE2/B0AT1 alleviated lipopolysaccharide (LPS)-induced diarrhea and promoted intestinal barrier recovery via transport of Trp. The levels of the aryl hydrocarbon receptor (AhR) and mechanistic target of rapamycin (mTOR) pathways were altered by ACE2. Dietary Trp supplementation in LPS-treated weaned piglets revealed that Trp alleviated diarrhea by promoting ACE2/B0AT1 expression, and examination of intestinal morphology revealed that the damage to the intestinal barrier was repaired. Our study demonstrated that ACE2 accompanied by B0AT1 mediated the alleviation of diarrhea by Trp through intestinal barrier repair via the mTOR pathway.

Biohybrid microrobots regulate colonic cytokines and the epithelium barrier in inflammatory bowel disease.

Cytokines have been identified as key contributors to the development of inflammatory bowel disease (IBD), yet conventional treatments often prove inadequate and carry substantial side effects. Here, we present an innovative biohybrid robotic system, termed "algae-MΦNP-robot," for addressing IBD by actively neutralizing colonic cytokine levels. Our approach combines moving green microalgae with macrophage membrane-coated nanoparticles (MΦNPs) to efficiently capture proinflammatory cytokines "on the fly." The dynamic algae-MΦNP-robots outperformed static counterparts by enhancing cytokine removal through continuous movement, better distribution, and extended retention in the colon. This system is encapsulated in an oral capsule, which shields it from gastric acidity and ensures functionality upon reaching the targeted disease site. The resulting algae-MΦNP-robot capsule effectively regulated cytokine levels, facilitating the healing of damaged epithelial barriers. It showed markedly improved prevention and treatment efficacy in a mouse model of IBD and demonstrated an excellent biosafety profile. Overall, our biohybrid algae-MΦNP-robot system offers a promising and efficient solution for IBD, addressing cytokine-related inflammation effectively.

Ileal Crohn's Disease Exhibits Reduced Activity of Phospholipase C-ß3-Dependent Wnt/ß-Catenin Signaling Pathway.

Crohn's disease is a chronic, debilitating, inflammatory bowel disease. Here, we report a critical role of phospholipase C-ß3 (PLC-ß3) in intestinal homeostasis. In PLC-ß3-deficient mice, exposure to oral dextran sodium sulfate induced lethality and severe inflammation in the small intestine. The lethality was due to PLC-ß3 deficiency in multiple non-hematopoietic cell types. PLC-ß3 deficiency resulted in reduced Wnt/ß-catenin signaling, which is essential for homeostasis and the regeneration of the intestinal epithelium. PLC-ß3 regulated the Wnt/ß-catenin pathway in small intestinal epithelial cells (IECs) at transcriptional, epigenetic, and, potentially, protein-protein interaction levels. PLC-ß3-deficient IECs were unable to respond to stimulation by R-spondin 1, an enhancer of Wnt/ß-catenin signaling. Reduced expression of PLC-ß3 and its signature genes was found in biopsies of patients with ileal Crohn's disease. PLC-ß regulation of Wnt signaling was evolutionally conserved in Drosophila. Our data indicate that a reduction in PLC-ß3-mediated Wnt/ß-catenin signaling contributes to the pathogenesis of ileal Crohn's disease.

Comparative studies on the intestinal health of wild and cultured ricefield eel (Monopterus albus).

Fish intestinal health under intensive aquaculture mode plays an important role in growth, development, and immune function. The present study was aimed to systematically investigate the differences of intestinal health between wild and cultured Monopterus albus by biochemical parameters, histomorphology, and molecular biology. A total of 15 healthy M. albus per group, with an average body weight of 45 g, were sampled to analyze intestinal health parameters. Compared with wild fish, the cultured M. albus in the foregut had lower trypsin, lipase, SOD, CAT, T-AOC, and GSH-Px activities (P < 0.05) and higher amylase activity and MDA content (P < 0.05). The villus circumference and goblet cells in the cultured group were significantly lower than those in the wild group (P < 0.05). In addition, the cultured fish showed lower relative expression levels of occludin, zo-1, zo-2, claudin-12, claudin-15, mucin5, mucin15, lysozyme, complement 3, il-10, tgf-ß1, tgf-ß2, and tgf-ß3 (P < 0.05) and higher il-1ß, il-6, il-8, tnf-a, and ifnγ mRNA expressions than those of wild fish (P < 0.05). In terms of gut microbiota, the cultured group at the phylum level displayed higher percentages of Chlamydiae and Spirochaetes and lower percentages of Firmicutes, Bacteroidetes, Actinobacteria, Cyanobacteria, and Verrucomicrobia compared to the wild group (P < 0.05). At the genus level, higher abundances of Pseudomonadaceae_Pseudomonas and Spironema and lower abundances of Lactococcus and Cetobacterium were observed in the cultured group than in the wild group (P < 0.05). To our knowledge, this is the first investigation of the intestinal health status between wild and cultured M. albus in terms of biochemistry, histology, and molecular biology levels. Overall, the present study showed significant differences in intestinal health between wild and cultured M. albus and the main manifestations that wild M. albus had higher intestinal digestion, antioxidant capacity, and intestinal barrier functions than cultured M. albus. These results would provide theoretical basis for the subsequent upgrading of healthy aquaculture technology and nutrient regulation of intestinal health of cultured M. albus.

The epithelial C15ORF48/miR-147-NDUFA4 axis is an essential regulator of gut inflammation, energy metabolism, and the microbiome.

Chronic inflammation is epidemiologically linked to the pathogenesis of gastrointestinal diseases, including inflammatory bowel disease (IBD) and colorectal cancer (CRC). However, our understanding of the molecular mechanisms controlling gut inflammation remains insufficient, hindering the development of targeted therapies for IBD and CRC. In this study, we uncovered C15ORF48/miR-147 as a negative regulator of gut inflammation, operating through the modulation of epithelial cell metabolism. C15ORF48/miR-147 encodes two molecular products, C15ORF48 protein and miR-147-3p microRNA, which are predominantly expressed in the intestinal epithelium. C15ORF48/miR-147 ablation leads to gut dysbiosis and exacerbates chemically induced colitis in mice. C15ORF48 and miR-147-3p work together to suppress colonocyte metabolism and inflammation by silencing NDUFA4, a subunit of mitochondrial complex IV (CIV). Interestingly, the C15ORF48 protein, a structural paralog of NDUFA4, contains a unique C-terminal α-helical domain crucial for displacing NDUFA4 from CIV and its subsequent degradation. NDUFA4 silencing hinders NF-κB signaling activation and consequently attenuates inflammatory responses. Collectively, our findings have established the C15ORF48/miR-147-NDUFA4 molecular axis as an indispensable regulator of gut homeostasis, bridging mitochondrial metabolism and inflammation.

Integrating Transcriptomics and Proteomics to Characterize the Intestinal Responses to Cadmium Exposure Using a Piglet Model.

Cadmium (Cd) is a heavy metal element with a wide range of hazards and severe biotoxicity. Since Cd can be easily accumulated in the edible parts of plants, the exposure of humans to Cd is mainly through the intake of Cd-contaminated food. However, the intestinal responses to Cd exposure are not completely characterized. Herein, we simulated laboratory and environmental Cd exposure by feeding the piglets with CdCl2-added rice and Cd-contaminated rice (Cdcr) contained diet, as piglets show anatomical and physiological similarities to humans. Subsequent analysis of the metal element concentrations showed that exposure to the two types of Cd significantly increased Cd levels in piglets. After verifying the expression of major Cd transporters by Western blots, multi-omics further expanded the possible transporters of Cd and found Cd exposure causes wide alterations in the metabolism of piglets. Of significance, CdCl2 and Cdcr exhibited different body distribution and metabolic rewiring, and Cdcr had stronger carcinogenic and diabetes-inducing potential. Together, our results indicate that CdCl2 had a significant difference compared with Cdcr, which has important implications for a more intense study of Cd toxicity.

Intestinal Epithelial Creatine Transporter SLC6A8 Dysregulation in Inflammation and in Response to Adherent Invasive E. coli Infection.

Creatine transporter (CrT1) mediates cellular uptake of creatine (Cr), a nutrient pivotal in maintaining energy homeostasis in various tissues including intestinal epithelial cells (IECs). The impact of CrT1 deficiency on the pathogenesis of various psychiatric and neurological disorders has been extensively investigated. However, there are no studies on its regulation in IECs in health and disease. Current studies have determined differential expression of CrT1 along the length of the mammalian intestine and its dysregulation in inflammatory bowel disease (IBD)-associated inflammation and Adherent Invasive E. coli (AIEC) infection. CrT1 mRNA and protein levels in normal intestines and their alterations in inflammation and following AIEC infection were determined in vitro in model IECs (Caco-2/IEC-6) and in vivo in SAMP1/YitFc mice, a model of spontaneous ileitis resembling human IBD. CrT1 is differentially expressed in different regions of mammalian intestines with its highest expression in jejunum. In vitro, CrT1 function (Na+-dependent 14C-Cr uptake), expression and promoter activity significantly decreased following TNFα/IL1ß treatments and AIEC infection. SAMP1 mice and ileal organoids generated from SAMP1 mice also showed decreased CrT1 mRNA and protein compared to AKR controls. Our studies suggest that Cr deficiency in IECs secondary to CrT1 dysregulation could be a key factor contributing to IBD pathogenesis.

Intestinal Ketogenesis and Permeability.

Consumption of a high-fat diet (HFD) has been suggested as a contributing factor behind increased intestinal permeability in obesity, leading to increased plasma levels of microbial endotoxins and, thereby, increased systemic inflammation. We and others have shown that HFD can induce jejunal expression of the ketogenic rate-limiting enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS). HMGCS is activated via the free fatty acid binding nuclear receptor PPAR-α, and it is a key enzyme in ketone body synthesis that was earlier believed to be expressed exclusively in the liver. The function of intestinal ketogenesis is unknown but has been described in suckling rats and mice pups, possibly in order to allow large molecules, such as immunoglobulins, to pass over the intestinal barrier. Therefore, we hypothesized that ketone bodies could regulate intestinal barrier function, e.g., via regulation of tight junction proteins. The primary aim was to compare the effects of HFD that can induce intestinal ketogenesis to an equicaloric carbohydrate diet on inflammatory responses, nutrition sensing, and intestinal permeability in human jejunal mucosa. Fifteen healthy volunteers receiving a 2-week HFD diet compared to a high-carbohydrate diet were compared. Blood samples and mixed meal tests were performed at the end of each dietary period to examine inflammation markers and postprandial endotoxemia. Jejunal biopsies were assessed for protein expression using Western blotting, immunohistochemistry, and morphometric characteristics of tight junctions by electron microscopy. Functional analyses of permeability and ketogenesis were performed in Caco-2 cells, mice, and human enteroids. Ussing chambers were used to analyze permeability. CRP and ALP values were within normal ranges and postprandial endotoxemia levels were low and did not differ between the two diets. The PPARα receptor was ketone body-dependently reduced after HFD. None of the tight junction proteins studied, nor the basal electrical parameters, were different between the two diets. However, the ketone body inhibitor hymeglusin increased resistance in mucosal biopsies. In addition, the tight junction protein claudin-3 was increased by ketone inhibition in human enteroids. The ketone body ß-Hydroxybutyrate (ßHB) did not, however, change the mucosal transition of the large-size molecular FD4-probe or LPS in Caco-2 and mouse experiments. We found that PPARα expression was inhibited by the ketone body ßHB. As PPARα regulates HMGCS expression, the ketone bodies thus exert negative feedback signaling on their own production. Furthermore, ketone bodies were involved in the regulation of permeability on intestinal mucosal cells in vitro and ex vivo. We were not, however, able to reproduce these effects on intestinal permeability in vivo in humans when comparing two weeks of high-fat with high-carbohydrate diet in healthy volunteers. Further, neither the expression of inflammation markers nor the aggregate tight junction proteins were changed. Thus, it seems that not only HFD but also other factors are needed to permit increased intestinal permeability in vivo. This indicates that the healthy gut can adapt to extremes of macro-nutrients and increased levels of intestinally produced ketone bodies, at least during a shorter dietary challenge.

A Quantity-Dependent Nonlinear Model of Sodium Cromoglycate Suppression on Beta-Conglycinin Transport.

Understanding the transport mechanism is crucial for developing inhibitors that block allergen absorption and transport and prevent allergic reactions. However, the process of how beta-conglycinin, the primary allergen in soybeans, crosses the intestinal mucosal barrier remains unclear. The present study indicated that the transport of beta-conglycinin hydrolysates by IPEC-J2 monolayers occurred in a time- and quantity-dependent manner. The beta-conglycinin hydrolysates were absorbed into the cytoplasm of IPEC-J2 monolayers, while none were detected in the intercellular spaces. Furthermore, inhibitors such as methyl-beta-cyclodextrin (MßCD) and chlorpromazine (CPZ) significantly suppressed the absorption and transport of beta-conglycinin hydrolysates. Of particular interest, sodium cromoglycate (SCG) exhibited a quantity-dependent nonlinear suppression model on the absorption and transport of beta-conglycinin hydrolysates. In conclusion, beta-conglycinin crossed the IPEC-J2 monolayers through a transcellular pathway, involving both clathrin-mediated and caveolae-dependent endocytosis mechanisms. SCG suppressed the absorption and transport of beta-conglycinin hydrolysates by the IPEC-J2 monolayers by a quantity-dependent nonlinear model via clathrin-mediated and caveolae-dependent endocytosis. These findings provide promising targets for both the prevention and treatment of soybean allergies.

Effects of Cannabinoids on Intestinal Motility, Barrier Permeability, and Therapeutic Potential in Gastrointestinal Diseases.

Cannabinoids and their receptors play a significant role in the regulation of gastrointestinal (GIT) peristalsis and intestinal barrier permeability. This review critically evaluates current knowledge about the mechanisms of action and biological effects of endocannabinoids and phytocannabinoids on GIT functions and the potential therapeutic applications of these compounds. The results of ex vivo and in vivo preclinical data indicate that cannabinoids can both inhibit and stimulate gut peristalsis, depending on various factors. Endocannabinoids affect peristalsis in a cannabinoid (CB) receptor-specific manner; however, there is also an important interaction between them and the transient receptor potential cation channel subfamily V member 1 (TRPV1) system. Phytocannabinoids such as Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) impact gut motility mainly through the CB1 receptor. They were also found to improve intestinal barrier integrity, mainly through CB1 receptor stimulation but also via protein kinase A (PKA), mitogen-associated protein kinase (MAPK), and adenylyl cyclase signaling pathways, as well as by influencing the expression of tight junction (TJ) proteins. The anti-inflammatory effects of cannabinoids in GIT disorders are postulated to occur by the lowering of inflammatory factors such as myeloperoxidase (MPO) activity and regulation of cytokine levels. In conclusion, there is a prospect of utilizing cannabinoids as components of therapy for GIT disorders.

Gut Microbiota Alleviates Intestinal Injury Induced by Extended Exposure to Light via Inhibiting the Activation of NLRP3 Inflammasome in Broiler Chickens.

Light pollution is a potential risk for intestinal health in humans and animals. The gut microbiota is associated with the development of intestinal inflammation induced by extended exposure to light, but the underlying mechanism is not yet clear. The results of this study showed that extended exposure to light (18L:6D) damaged intestinal morphology, downregulated the expression of tight junction proteins, and upregulated the expression of the NLRP3 inflammasome and the concentration of pro-inflammatory cytokines. In addition, extended exposure to light significantly decreased the abundance of Lactobacillus, Butyricicoccus, and Sellimonas and increased the abundance of Bifidobacterium, unclassified Oscillospirales, Family_XIII_UCG-001, norank_f__norank_o__Clostridia_vadinBB60_group, and Defluviitaleaceae_UCG-01. Spearman correlation analysis indicated that gut microbiota dysbiosis positively correlated with the activation of the NLRP3 inflammasome. The above results indicated that extended exposure to light induced intestinal injury by NLRP3 inflammasome activation and gut microbiota dysbiosis. Antibiotic depletion intestinal microbiota treatment and cecal microbiota transplantation (CMT) from the 12L:12D group to 18L:6D group indicated that the gut microbiota alleviated intestinal inflammatory injury induced by extended exposure to light via inhibiting the activation of the NLRP3 inflammasome. In conclusion, our findings indicated that the gut microbiota can alleviate intestinal inflammation induced by extended exposure to light via inhibiting the activation of the NLRP3 inflammasome.

A Flexible Semi-automated Assay for Assessing Radiation-sensitization and Toxicity in the Mouse Intestine.

BACKGROUND/AIM: The aim of this study was to develop an enhanced intestinal toxicity assay with three outputs assessing proliferation, villi morphology and DNA damage after irradiation. MATERIALS AND METHODS: Whole 5 cm jejunal lengths were collected from mice following total body x-ray irradiation (0-15 Gy) at 0-84 h. Tissues were wrapped into swirls for cryopreservation and immunohistochemically stained for EdU, CD31, and γH2AX. A semi-automated image analysis was developed for the proliferation, villi morphology, and DNA damage models. RESULTS: Proliferation assessed via EdU staining varied with cycles of damage repair, hyperproliferation, and homeostasis after radiation, with the time to onset of each cycle variable based on radiation dose. An analysis model evaluating the amount of proliferation per unit length of jejunum analyzed was developed, with a dose-response curve identified at 48 h post treatment. The villi length model measured the length of intact and healthy CD31-stained capillary beds between the crypts and villi tips at 3.5 days post treatment within a 0-10 Gy dose range. The DNA damage model evaluated the intensity of γH2AX staining within cellular nuclei, with a useful dose-response identified at 1 h post-radiation treatment. CONCLUSION: This assay demonstrates flexibility for assessing radiation-induced damage, with analysis of proliferation, villi length, or direct DNA damage achievable at defined time points and within useful radiation dose curves. The software-assisted image analysis allows for rapid, comprehensive, and objective data generation with an assay turnover time of days instead of weeks on samples that are representative of most of the treated jejunum.