Maintenance Of Intestinal Barrier Integrity Research Articles

The dual effects of dexmedetomidine on intestinal barrier and intestinal motility during sepsis

BackgroundSepsis, characterized by dysregulated host responses to infection, remains a critical global health concern, with high morbidity and mortality rates. The gastrointestinal tract assumes a pivotal role in sepsis due to its dual functionality as a protective barrier against injurious agents and as a regulator of motility. Dexmedetomidine, an α2-adrenergic agonist commonly employed in critical care settings, exhibits promise in influencing the maintenance of intestinal barrier integrity during sepsis. However, its impact on intestinal motility, a crucial component of intestinal function, remains incompletely understood. MethodsIn this study, we investigated dexmedetomidine’s multifaceted effects on intestinal barrier function and motility during sepsis using both in vitro and in vivo models. Sepsis was induced in Sprague-Dawley rats via cecal ligation and puncture. Rats were treated with dexmedetomidine post-cecal ligation and puncture, and various parameters were assessed to elucidate dexmedetomidine's impact. ResultsOur findings revealed a dichotomous influence of dexmedetomidine on intestinal physiology. In septic rats, dexmedetomidine administration resulted in improved intestinal barrier integrity, as evidenced by reduced mucosal hyper-permeability and morphological alterations. However, a contrasting effect was observed on intestinal motility, as dexmedetomidine treatment inhibited both the frequency and amplitude of contractions in isolated intestinal strips and decreased the distance of ink migration in vivo. Additionally, dexmedetomidine suppressed the secretion of pro-motility hormones while having no influence on hormones that inhibit intestinal peristalsis. ConclusionThe study revealed that during sepsis, dexmedetomidine exhibited protective effects on barrier integrity, although concurrently it hindered intestinal motility, partly attributed to its modulation of pro-motility hormone secretion. These findings underscore the necessity of a comprehensive understanding of dexmedetomidine’s impact on multiple facets of gastrointestinal physiology in sepsis management, offering potential implications for therapeutic strategies and patient care.

The Potential Role of Vitamin E and the Mechanism in the Prevention and Treatment of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) includes ulcerative colitis and Crohn's disease, and it is a multifactorial disease of the intestinal mucosa. Oxidative stress damage and inflammation are major risk factors for IBD. Vitamin E has powerful antioxidant and anti-inflammatory effects. Our previous work and other investigations have shown that vitamin E has a positive effect on the prevention and treatment of IBD. In this paper, the source and structure of vitamin E and the potential mechanism of vitamin E's role in IBD were summarized, and we also analyzed the status of vitamin E deficiency in patients with IBD and the effect of vitamin E supplementation on IBD. The potential mechanisms by which vitamin E plays a role in the prevention and treatment of IBD include improvement of oxidative damage, enhancement of immunity, maintenance of intestinal barrier integrity, and suppression of inflammatory cytokines, modulating the gut microbiota and other relevant factors. The review will improve our understanding of the complex mechanism by which vitamin E inhibits IBD, and it also provides references for doctors in clinical practice and researchers in this field.

From the Gut to the Brain: The Role of Enteric Glial Cells and Their Involvement in the Pathogenesis of Parkinson's Disease.

The brain-gut axis has been identified as an important contributor to the physiopathology of Parkinson's disease. In this pathology, inflammation is thought to be driven by the damage caused by aggregation of α-synuclein in the brain. Interestingly, the Braak's theory proposes that α-synuclein misfolding may originate in the gut and spread in a "prion-like" manner through the vagus nerve into the central nervous system. In the enteric nervous system, enteric glial cells are the most abundant cellular component. Several studies have evaluated their role in Parkinson's disease. Using samples obtained from patients, cell cultures, or animal models, the studies with specific antibodies to label enteric glial cells (GFAP, Sox-10, and S100β) seem to indicate that activation and reactive gliosis are associated to the neurodegeneration produced by Parkinson's disease in the enteric nervous system. Of interest, Toll-like receptors, which are expressed on enteric glial cells, participate in the triggering of immune/inflammatory responses, in the maintenance of intestinal barrier integrity and in the configuration of gut microbiota; thus, these receptors might contribute to Parkinson's disease. External factors like stress also seem to be relevant in its pathogenesis. Some authors have studied ways to reverse changes in EGCs with interventions such as administration of Tryptophan-2,3-dioxygenase inhibitors, nutraceuticals, or physical exercise. Some researchers point out that beyond being activated during the disease, enteric glial cells may contribute to the development of synucleinopathies. Thus, it is still necessary to further study these cells and their role in Parkinson's disease.

The septate junction component bark beetle is required for Drosophila intestinal barrier function and homeostasis

Age-related loss of intestinal barrier function has been documented across species, but the causes remain unknown. The intestinal barrier is maintained by tight junctions (TJs) in mammals and septate junctions (SJs) in insects. Specialized TJs/SJs, called tricellular junctions (TCJs), are located at the nexus of three adjacent cells, and we have shown that aging results in changes to TCJs in intestines ofadult Drosophila melanogaster. We now demonstrate that localization of theTCJ protein bark beetle (Bark) decreases in aged flies. Depletion of bark fromenterocytes in young flies led to hallmarks of intestinal aging and shortened lifespan, whereas depletion of bark in progenitor cells reduced Notch activity, biasing differentiation toward the secretory lineage. Our data implicate Bark in EC maturation and maintenance of intestinal barrier integrity. Understanding the assembly and maintenance of TCJs to ensure barrier integrity may lead to strategies to improve tissue integrity when function is compromised.

Anti-Inflammatory Potential of Brassicaceae-Derived Phytochemicals: In Vitro and In Vivo Evidence for a Putative Role in the Prevention and Treatment of IBD.

Inflammatory bowel disease (IBD) is a group of intestinal disorders, of unknown etiology, characterized by chronic inflammation within the gut. They are gradually becoming critical because of the increasing incidence worldwide and improved diagnosis. Due to the important side effects observed during conventional therapy, natural bioactive components are now under intense investigation for the prevention and treatment of chronic illnesses. The Brassicaceae family comprises vegetables widely consumed all over the world. In recent decades, a growing body of literature has reported that extracts from the Brassicaceae family and their purified constituents have anti-inflammatory properties, which has generated interest from both the scientific community and clinicians. In this review, data from the literature are scrutinized and concisely presented demonstrating that Brassicaceae may have anti-IBD potential. The excellent biological activities of Brassicacea are widely attributable to their ability to regulate the levels of inflammatory and oxidant mediators, as well as their capacity for immunomodulatory regulation, maintenance of intestinal barrier integrity and intestinal flora balance. Possible future applications of bioactive-derived compounds from Brassicaceae for promoting intestinal health should be investigated.

The protective effects of the microbiota on early childhood colonization through parturition, breastfeeding and feeding

The existing microbiota in humans is the result of years of evolution of a symbiotic relationship. this relationship has brought us numerous benefits, including protection against pathogens, maintenance of intestinal barrier integrity, nutrient and drug metabolism, vitamin synthesis (k and b12), and temperature production and nutrient availability. microorganisms are in large numbers in the human organism, reaching approximately ten times more microbial cells than cells. The gut microbiota plays an important role in the normal function of the gut and maintenance of the host's health. influencing not only gastrointestinal diseases, but the healthy and microbiologically balanced intestinal microbiota results in a normal performance of the host's physiological functions, which will ensure an Microbiota improvement in the quality of life.

NF-κB-coupled IL17 mediates inflammatory signaling and intestinal inflammation in Artemia sinica

Nuclear factor-κB (NF-κB) plays a role as a rheostatic transcription factor in regulating intestinal inflammation, and its disruption or constitutive activation leads to inflammation and injury. However, the molecular mechanisms of NF-κB regulation remain largely unknown. In this study, the NF-κB-regulated host defenses against pathogen infections and facilitation of IL17 expression during stimulation with different bacteria were investigated. Intestinal inflammation was induced by dextran sulfate sodium, and NF-κB activity was inhibited in an intestinal injury model. Mannose receptor C type, ABF1/2, serpin B13, lysozyme, and β-arrestin were significantly controlled by NF-κB in the inflamed intestinal tissue. High levels of NF-κB activation resulted in less pervasive intestinal damage and the maintenance of intestinal barrier integrity. Intestinal injury robustly increased the expression of IL17. NF-κB activation was enhanced by IL17 deficiency in the intestinal injury model. IL17 inhibition aggravated intestinal inflammation, leading to loss of epithelial architecture and the infiltration of inflammatory cells. These data suggest that NF-κB and IL17 play key mediator roles in the maintenance of gut epithelial integrity and immune homeostasis.

Metabolic Action of Metformin

Metformin, a cheap and safe biguanide derivative, due to its ability to influence metabolism, is widely used as a first-line drug for type 2 diabetes (T2DM) treatment. Therefore, the aim of this review was to present the updated biochemical and molecular effects exerted by the drug. It has been well explored that metformin suppresses hepatic glucose production in both AMPK-independent and AMPK-dependent manners. Substantial scientific evidence also revealed that its action is related to decreased secretion of lipids from intestinal epithelial cells, as well as strengthened oxidation of fatty acids in adipose tissue and muscles. It was recognized that metformin’s supra-therapeutic doses suppress mitochondrial respiration in intestinal epithelial cells, whereas its therapeutic doses elevate cellular respiration in the liver. The drug is also suggested to improve systemic insulin sensitivity as a result of alteration in gut microbiota composition, maintenance of intestinal barrier integrity, and alleviation of low-grade inflammation.

Desmosome Dysregulation and MLC Phosphorylation Contribute to Loss of Barrier Integrity in DRA KO mice

DRA or SLC26A3 is the key transporter for chloride absorption in the mammalian intestine. Our recent studies demonstrated that DRA deficiency increased paracellular permeability and altered tight and adherens junction protein expression in mouse colon. However, the mechanisms underlying increased paracellular permeability and the role of intercellular junctional proteins (desmosomes) that play a critical role in the maintenance of intestinal barrier integrity in DRA KO mice are not well understood. Aim The current studies were undertaken to examine the role of desmosomes and Rho‐ROCK‐MLC phosphorylation pathway in colonic barrier integrity in DRA KO mice.MethodDRA KO and WT mice (M/F, 8‐10 weeks old) were used as an in‐vivo model. Protein expression was measured by immunoblotting and immunofluorescence, whereas mRNA expression was measured by QRT‐PCR and Rho A activity was examined utilizing the G‐LISA kit.ResultsOur results showed that the mRNA expression of desmosome proteins, desmoglein‐2 (DSG2) and desmocollin‐2 (DSC2) was significantly reduced (50‐70%, p<0.05) in DRA KO colons compared to wild‐type mice. Similarly, DSG2 protein expression was also significantly downregulated in DRA KO mice colon (~ 50%, p<0.05) as assessed by immunoblotting and immunostaining. We also examined the role of Rho‐ROCK‐MLC2 phosphorylation pathway in DRA KO mice. Interestingly, DRA KO mice colon showed a significant increase in Rho A protein expression (~5‐fold, p<0.01) and Rho A activity (~ 3.5‐fold, p<0.05) compared to WT. Furthermore, DRA KO mice also exhibited a significant decrease in ezrin phosphorylation (a downstream target of Rho A signaling) (~ 2‐fold, p<0.05) compared to WT mice. In addition, another downstream target of the Rho A pathway, MYPT‐1 (Myosin Phosphatase Target Subunit 1), also showed a significant decrease (~ 60%, p<0.05) in its protein expression in DRA KO mice. MYPT‐1 downregulation in DRA KO mice was associated with a significant increase in MLC‐2 phosphorylation (~ 2‐fold, p<0.05), which may have contributed to barrier dysfunction in colon of DRA KO mice. Since, our recent studies showed microbial dysbiosis in DRA KO mice, it was of interest to examine the role of gut microbiome by co‐housing WT and KO mice for 4 weeks for microbial exchange. Interestingly, co‐housed DRA KO mice also showed a significant but lower increase in Rho A expression (~ 3‐fold, p<0.05) and downregulation of MYPT‐1 expression (~ 60%, p<0.05) compared to co‐housed WT mice indicating that the regulation of Rho A and MYPT‐1 expression was only partly dependent on microbial dysbiosis observed in DRA KO mice.ConclusionOur studies highlight the novel role of desmosome dysregulation and increased MLC phosphorylation in compromised colonic barrier integrity in DRA KO mice.

Mucosal-associated invariant T cells: A cryptic coordinator in HIV-infected immune reconstitution.

Human immunodeficiency virus type 1 (HIV-1) infection causes considerable morbidity and mortality worldwide. Although antiretroviral therapy (ART) has largely transformed HIV infection from a fatal disease to a chronic condition, approximately 10%-40% of HIV-infected individuals who receive effective ART and sustain long-term viral suppression still cannot achieve optimal immune reconstitution. These patients are called immunological nonresponders, a state associated with poor clinical prognosis. Mucosal-associated invariant T (MAIT) cells are an evolutionarily conserved unconventional T-cell subset defined by expression of semi-invariant αβ T-cell receptor (TCR), which recognizes metabolites derived from the riboflavin biosynthetic pathway presented on major histocompatibility complex-related protein-1. MAIT cells, which are considered to act as a bridge between innate and adaptive immunity, produce a wide range of cytokines and cytotoxic molecules upon activation through TCR-dependent and TCR-independent mechanisms, which is of major importance in defense against a variety of pathogens. In addition, MAIT cells are involved in autoimmune and immune-mediated diseases. The number of MAIT cells is dramatically and irreversibly decreased in the early stage of HIV infection and is not fully restored even after long-term suppressive ART. In light of the important role of MAIT cells in mucosal immunity and because microbial translocation is inversely associated with CD4+ T-cell counts, we propose that MAIT cells participate in the maintenance of intestinal barrier integrity and microbial homeostasis, thus further affecting immune reconstitution in HIV-infected individuals.

Urolithin A attenuates arsenic-induced gut barrier dysfunction.

Environmental chemicals such as inorganic arsenic (iAs) significantly contribute to redox toxicity in the human body by enhancing oxidative stress. Imbalanced oxidative stress rapidly interferes with gut homeostasis and affects variety of cellular processes such as proliferation, apoptosis, and maintenance of intestinal barrier integrity. It has been shown that gut microbiota are essential to protect against iAs3+-induced toxicity. However, the effect of microbial metabolites on iAs3+-induced toxicity and loss of gut barrier integrity has not been investigated. The objectives of the study are to investigate impact of iAs on gut barrier function and determine benefits of gut microbial metabolite, urolithin A (UroA) against iAs3+-induced adversaries on gut epithelium. We have utilized both colon epithelial cells and in a human intestinal 3D organoid model system to investigate iAs3+-induced cell toxicity, oxidative stress, and gut barrier dysfunction in the presence or absence of UroA. Here, we report that treatment with UroA attenuated iAs3+-induced cell toxicity, apoptosis, and oxidative stress in colon epithelial cells. Moreover, our data suggest that UroA significantly reduces iAs3+-induced gut barrier permeability and inflammatory markers in both colon epithelial cells and in a human intestinal 3D organoid model system. Mechanistically, UroA protected against iAs3+-induced disruption of tight junctional proteins in intestinal epithelial cells through blockade of oxidative stress and markers of inflammation. Taken together, our studies for the first time suggest that microbial metabolites such as UroA can potentially be used to protect against environmental hazards by reducing intestinal oxidative stress and by enhancing gut barrier function.

Dual therapy with zinc acetate and rifaximin prevents from ethanol-induced liver fibrosis by maintaining intestinal barrier integrity.

BACKGROUNDHepatic overload of gut-derived lipopolysaccharide dictates the progression of alcoholic liver disease (ALD) by inducing oxidative stress and activating Kupffer cells and hepatic stellate cells through toll-like receptor 4 signaling. Therefore, targeting the maintenance of intestinal barrier integrity has attracted attention for the treatment of ALD. Zinc acetate and rifaximin, which is a nonabsorbable antibiotic, had been clinically used for patients with cirrhosis, particularly those with hepatic encephalopathy, and had been known to improve intestinal barrier dysfunction. However, only few studies focused on their efficacies in preventing the ALD-related fibrosis development. AIMTo investigate the effects of a combined zinc acetate with rifaximin on liver fibrosis in a mouse ALD model.METHODSTo induce ALD-related liver fibrosis, female C57BL/6J mice were fed a 2.5% (v/v) ethanol-containing Lieber-DeCarli liquid diet and received intraperitoneal carbon tetrachloride (CCl4) injection twice weekly (1 mL/kg) for 8 wk. Zinc acetate (100 mg/L) and/or rifaximin (100 mg/L) were orally administered during experimental period. Hepatic steatosis, inflammation and fibrosis as well as intestinal barrier function were evaluated by histological and molecular analyses. Moreover, the direct effects of both agents on Caco-2 barrier function were assessed by in vitro assays.RESULTSIn the ethanol plus CCl4-treated mice, combination of zinc acetate and rifaximin attenuated oxidative lipid peroxidation with downregulation of Nox2 and Nox4. This combination significantly inhibited the Kupffer cells expansion and the proinflammatory response with blunted hepatic exposure of lipopolysaccharide and the toll-like receptor 4/nuclear factor kB pathway. Consequently, liver fibrosis and hepatic stellate cells activation were efficiently suppressed with downregulation of Mmp-2, -9, -13, and Timp1. Both agents improved the atrophic changes and permeability in the ileum, with restoration of tight junction proteins (TJPs) by decreasing the expressions of tumor necrosis factor α and myosin light chain kinase. In the in vitro assay, both agents directly reinforced ethanol or lipopolysaccharide-stimulated paracellular permeability and upregulated TJPs in Caco-2 cells.CONCLUSIONDual therapy with zinc acetate and rifaximin may serve as a strategy to prevent ALD-related fibrosis by maintaining intestinal barrier integrity.

Protective effect of exopolysaccharide fraction from Bacillus subtilis against dextran sulfate sodium-induced colitis through maintenance of intestinal barrier and suppression of inflammatory responses

We previously reported that an exopolysaccharide-enriched fraction from Bacillus subtilis J92 (B-EPS) could improve immune functions by regulating the immunological parameters of IFN-γ-primed macrophages, CD3/CD28-stimulated splenocytes, and in cyclophosphamide-induced immunosuppressed mice. In the present study, we investigated whether B-EPS contributes to the maintenance of intestinal barrier integrity in a dextran sodium sulfate (DSS)-induced colitis mouse model that mimics human inflammatory bowel disease (IBD). B-EPS treatment improved histological characteristics and common features including a high disease activity index (DAI), an increased spleen weight, and colon shortening in DSS-induced colitis. B-EPS also effectively restored intestinal barrier function by modulating tight junction-related proteins (claudin-1, claudin-2, and occludin) and epithelial-mesenchymal transition (EMT) marker proteins (E-cadherin, N-cadherin, and vimentin). Moreover, B-EPS downregulated immune cell infiltration and inflammatory responses including the production of inflammatory cytokines, such as IL-6 and IL-1β, and activation of nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3). Taken together, these results suggest that B-EPS could serve as a functional food ingredient for improving intestinal barrier function and alleviating colonic inflammation in IBD.

Stachyose Improves the Effects of Berberine on Glucose Metabolism by Regulating Intestinal Microbiota and Short-Chain Fatty Acids in Spontaneous Type 2 Diabetic KKAy Mice.

Berberine (BBR) has the beneficial effects of anti-inflammation, anti-bacteria, and anti-diabetes. The clinical application of BBR has been hindered by its poor gastrointestinal absorption. Stachyose (Sta), a prebiotic agent, improves the composition of gut microbiota and benefits for diabetes. We therefore investigated whether Sta improves the anti-diabetic actions of BBR using KKAy mice. Here, we find that the combination of BBR and Sta is more effective than BBR alone in blood glucose control, improvement of insulin resistance and islet functions, inflammatory mediators decrease, and maintenance of intestinal barrier integrity. Gut microbiota analysis demonstrates that both BBR and combined administration enhance the abundance of Bacteroidaceae and Akkermansiaceae and decrease Lachnospiraceae levels, whereas Akkermansiaceae elevation due to the administration of BBR with Sta is more significant than BBR alone. Interestingly, the proportion of Lactobacillaceae increases with combination treatment, but is diminished by BBR. Additionally, BBR with Sta significantly reduces the concentrations of fecal short-chain fatty acids compared to BBR. Collectively, these results indicate that the combination of BBR and Sta imparts better effects on the maintenance of glycemia and intestinal homeostasis than BBR alone by modulating gut microbiota and short-chain fatty acids, thereby providing a novel approach for the treatment of type 2 diabetes mellitus.

P: 1 Genetic Fingerprint of Hepatic Encephalopathy Risk in Liver Cirrhosis

BACKGROUND: To determine the impact of genetic factors on the development of hepatic encephalopathy (HE) in patients with liver cirrhosis. METHODS: Patients suffering from compensated liver cirrhosis [n = 434; estimation cohort (n = 294) and validation cohort (n = 140)] were included. Patients were followed up for five years until HE bouts, liver transplant, or death. Methods: Patients were genotyped for 62 candidate SNPs (genes involved in the pathophysiology of HE: inflammation, ammonia and glutamine metabolism, intestinal barrier integrity and oxidative stress) by using OpenArray custom plates. Likewise, a haplotype formed by four SNPs within GLS plus the length of a microsatellite in the promoter region of GLS were determined (Romero-Gómez et al. Ann Intern Med 2010). Statistical analysis was performed by Cox regression and Kaplan-Meier for continuous and categorical data. Significant variables, and those known as weighted prognostic indicators, were entered into multivariable models by competing risks, according to Fine and Gray's method. RESULTS: In the estimation cohort, competing risks analysis showed GLS mutations, FUT2-(rs601338), TLR9-(rs5743836), SLC1A3-(rs2562582) and SLC1A5-(rs313853), together with MELD, albumin, sodium and previous episodes of HE as variables independently associated to HE development. Those genes encode for proteins involved in maintenance of intestinal barrier integrity by host-microbial interactions (FUT2), pro-inflammatory response triggered by pathogens (TLR-9) and glutamine transport (SLC1A3 and SLC1A5). Combining these genetic factors according to number of alleles at risk, three levels of risk patients were defined: low, mid or high risk [sHR: 1; 6.5 (1.8–22.9) P = 0.004; 27.1 (7.5–96.8) P < 0.001, respectively] (C-index = 0.82). This regression model performed in a similar manner in the validation cohort [sHR: 1; 4.2 (1.2–14.3) P = 0.024; 10.0 (2.7–36.7) P < 0.001] (C-index = 0.78). Cumulative survival free of HE after 5 years was also influenced by this genetic fingerprint: 95.3%, 77.0% and 42.5% for the low, mid and high-risk groups (log-Rank 53.1; P < 0.001) in the estimation, and 85.2%, 56.0% and 40.0% (log-Rank 14.1; P < 0.001) in the validation cohort, respectively (Figure 1). CONCLUSIONS: Combination of unfavorable variants could predict HE. This genetic fingerprint could be implemented in clinical practice for decision making in the management of cirrhotic patients. Besides, this work emphasizes the role of these pathways in the pathophysiology of HE and brings out novel genes as potential therapeutic targets.

Bryostatin-1 ameliorated experimental colitis in Il-10-/- Mice by protecting the intestinal barrier and limiting immune dysfunction.

Bryostatin‐1 (Bry‐1) has been proven to be effective and safe in clinical trials of a variety of immune‐related diseases. However, little is known about its effect on Crohn's disease (CD). We aimed to investigate the impact of Bry‐1 on CD‐like colitis and determine the mechanism underlying this effect. In the present study, 15‐week‐old male Il‐10 −/− mice with spontaneous colitis were divided into positive control and Bry‐1‐treated (Bry‐1, 30 μg/kg every other day, injected intraperitoneally for 4 weeks) groups. Age‐matched, male wild‐type (WT) mice were used as a negative control. The effects of Bry‐1 on colitis, intestinal barrier function and T cell responses as well as the potential regulatory mechanisms were evaluated. We found that the systemic delivery of Bry‐1 significantly ameliorated colitis in Il‐10 −/− mice, as demonstrated by decreases in the disease activity index (DAI), inflammatory score and proinflammatory mediator levels. The protective effects of Bry‐1 on CD‐like colitis included the maintenance of intestinal barrier integrity and the helper T cell (Th)/regulatory T cell (Treg) balance. These effects of Bry‐1 may act in part through nuclear factor erythroid 2‐related factor 2 (Nrf2) signalling activation and STAT3/4 signalling inhibition. The protective effect of Bry‐1 on CD‐like colitis suggests Bry‐1 has therapeutic potential in human CD, particularly given the established clinical safety of Bry‐1.

Spontaneous colitis in IL-10-deficient mice was ameliorated via inhibiting glutaminase1.

Immunity imbalance and barrier damage in the intestinal mucosa are the main pathogenic factors of Crohn's disease (CD). Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide (BPTES) is a glutaminase 1 (Gls1) inhibitor with the dual functions of increasing glutamine levels and immune regulation. In this study, we focused on the role of BPTES in CD‐like enteritis and the possible mechanisms. We found that Gls1 expression was significantly increased in CD intestinal tissue compared with control tissue. Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide treatment significantly ameliorated chronic colitis in the IL‐10−/−, as manifested by decreased disease activity index, body weight change, histological inflammatory degree and inflammatory cytokine expression. Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide treatment exerted protective effects on CD that were associated with the maintenance of intestinal barrier integrity and the Th/Treg balance. Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide treatment may act in part through TCR‐mediated mammalian target of rapamycin complex 1 (mTORC1) signalling activation. In conclusion, inhibition of Gls1 expression attenuated chronic colitis by maintaining intestinal barrier integrity and the Th/Treg balance, thereby ameliorating CD‐like colitis.

Health Benefits of Heat-Killed (Tyndallized) Probiotics: An Overview.

Nowadays, the oral use of probiotics is widespread. However, the safety profile with the use of live probiotics is still a matter of debate. Main risks include: Cases of systemic infections due to translocation, particularly in vulnerable patients and pediatric populations; acquisition of antibiotic resistance genes; or interference with gut colonization in neonates. To avoid these risks, there is an increasing interest in non-viable microorganisms or microbial cell extracts to be used as probiotics, mainly heat-killed (including tyndallized) probiotic bacteria (lactic acid bacteria and bifidobacteria). Heat-treated probiotic cells, cell-free supernatants, and purified key components are able to confer beneficial effects, mainly immunomodulatory effects, protection against enteropathogens, and maintenance of intestinal barrier integrity. At the clinical level, products containing tyndallized probiotic strains have had a role in gastrointestinal diseases, including bloating and infantile coli—in combination with mucosal protectors—and diarrhea. Heat-inactivated probiotics could also have a role in the management of dermatological or respiratory allergic diseases. The reviewed data indicate that heat-killed bacteria or their fractions or purified components have key probiotic effects, with advantages versus live probiotics (mainly their safety profile), positioning them as interesting strategies for the management of common prevalent conditions in a wide variety of patients´ characteristics.

Intestinal HIF‐1α Deletion Exacerbates Alcoholic Liver Disease through Inducing Intestinal Dysbiosis and Barrier Dysfunction

ObjectivesAlcoholic liver disease (ALD) is characterized by gut dysbiosis and increased gut permeability. Hypoxia Induced Factor 1α (HIF‐1α) has been implicated in transcriptional regulation of intestinal barrier integrity and inflammation. We aimed to test the hypothesis that HIF‐1α plays a critical role in gut microbiota homeostasis and the maintenance of intestinal barrier integrity in a mouse model of ALD.MethodsWide type (WT) and intestinal epithelial‐specific HIF‐1α knockout mice (IEhif‐1α−/−) were pair‐fed modified Lieber‐DeCarli liquid diet containing 5% (w/v) alcohol or isocaloric maltose dextrin for 24 days. Serum levels of ALT and endotoxin were determined. Fecal microbiota were assessed. Liver steatosis and injury, and intestinal barrier integrity were evaluated.ResultsAlcohol feeding increased serum levels of ALT and LPS, hepatic triglyceride concentration, and liver injury in the WT mice. These deleterious effects were exaggerated in IEhif‐1α−/− mice. Alcohol exposure resulted in greater reduction of the expression of intestinal epithelial tight junction proteins, claudin‐1 and occludin, in IEhif‐1α−/− mice. In addition, cathelicidin‐related antimicrobial peptide (CRAMP) and intestinal trefoil factor (ITF) were further decreased by alcohol in IEhif‐1α−/− mice. Metagenomic analysis showed an increased gut dysbiosis with a significantly decreased firmicutes/bacteroidetes ratio in IEhif‐1α−/− mice compared to the WT mice exposed to alcohol. An increased abundance of Akkermansia and a decreased level of Lactobacillus in IEhif‐1α−/− mice were observed. Non‐absorbable antibiotics treatment reversed the liver steatosis in both WT and IEhif‐1α−/− mice.ConclusionIntestinal HIF‐1α is essential for the adaptation response to alcohol exposure‐induced changes in intestinal microbiota and barrier function associated with elevated endotoxemia and hepatic steatosis and injury.Support or Funding InformationNIHThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A Fixed Combination of Probiotics and Herbal Extracts Attenuates Intestinal Barrier Dysfunction from Inflammatory Stress in an In vitro Model Using Caco-2 Cells

Inflammatory Bowel Diseases (IBD), are considered a growing global disease, with about ten million people being affected worldwide. Maintenance of intestinal barrier integrity is crucial for preventing IBD onset and exacerbations. Some recent patents regarding oily formulations containing probiotics (WO2010122107A1 and WO2010103374A9) and the use of probiotics for gastrointestinal complaints (US20110110905A1 and US9057112B2) exist, or are pending application. In this work, we studied the effect of a fixed combination of registered Lactobacillus reuteri and Lactobacillus acidophilus strains and herbal extracts in an in vitro inflammation experimental model. Caco-2 cell monolayer was exposed to INF-γ+TNF-α or to LPS; Trans Epithelial Electrical Resistance (TEER) and paracellular permeability were investigated. ZO-1 and occludin Tight Junctions (TJs) were also investigated by mean of immunofluorescence. Pre-treatment with the fixed combination of probiotics and herbal extracts prevented the inflammation-induced TEER decrease, paracellular permeability increase and TJs translocation. In summary, the fixed combination of probiotics and herbal extracts investigated in this research was found to be an interesting candidate for targeting the re-establishment of intestinal barrier function in IBD conditions.