HIV-1 transgene expression in rats causes oxidant stress and alveolar epithelial barrier dysfunction

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Jacob Barbara A

2009-02-01

Full Text Available Abstract Background HIV-infected individuals are at increased risk for acute and chronic airway disease even though there is no evidence that the virus can infect the lung epithelium. Although HIV-related proteins including gp120 and Tat can directly cause oxidant stress and cellular dysfunction, their effects in the lung are unknown. The goal of this study was to determine the effects of HIV-1 transgene expression in rats on alveolar epithelial barrier function. Alveolar epithelial barrier function was assessed by determining lung liquid clearance in vivo and alveolar epithelial monolayer permeability in vitro. Oxidant stress in the alveolar space was determined by measuring the glutathione redox couple by high performance liquid chromatography, and the expression and membrane localization of key tight junction proteins were assessed. Finally, the direct effects of the HIV-related proteins gp120 and Tat on alveolar epithelial barrier formation and tight junction protein expression were determined. Results HIV-1 transgene expression caused oxidant stress within the alveolar space and impaired epithelial barrier function even though there was no evidence of overt inflammation within the airways. The expression and membrane localization of the tight junction proteins zonula occludens-1 and occludin were decreased in alveolar epithelial cells from HIV-1 transgenic rats. Further, treating alveolar epithelial monolayers from wild type rats in vitro with recombinant gp120 or Tat for 24 hours reproduced many of the effects on zonula occludens-1 and occludin expression and membrane localization. Conclusion Taken together, these data indicate that HIV-related proteins cause oxidant stress and alter the expression of critical tight junction proteins in the alveolar epithelium, resulting in barrier dysfunction.

The effect of topical treatments for CRS on the sinonasal epithelial barrier.

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Ramezanpour, M; Rayan, A; Smith, J L P; Vreugde, S

2017-06-01

Several topical treatments are used in the management of Chronic Rhinosinusitis (CRS), some of which the safety and efficacy has yet to be determined. The purpose of this study was to investigate the effect of commonly used topical treatments on the sinonasal epithelial barrier. Normal saline (0.9% Sodium Chloride), hypertonic saline (3% Sodium Chloride), FESS Sinu-Cleanse Hypertonic, FLO Sinus Care and Budesonide 1 mg/ 2 ml were applied to the apical side of air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs) from CRS patients (n=3) and non-CRS controls (n=3) for 24 hours. Epithelial barrier structure and function was assessed using trans-epithelial electrical resistance (TEER), measuring the passage of Fluorescein Isothiocyanate labelled Dextrans (FITC-Dextrans) and assessing the expression of the tight junction protein Zona Occludens-1 (ZO-1) using immunofluorescence. Toxicity was assessed using a Lactate Dehydrogenase (LDH) assay. Data was analysed using ANOVA, followed by Tukey HSD post hoc test. Hypertonic solution and budesonide significantly increased TEER values in CRS derived HNECs. In contrast, FESS Sinu-Cleanse Hypertonic significantly reduced TEER 5 minutes after application of the solution followed by an increase in paracellular permeability of FITC-Dextrans (30 minutes) and increased LDH levels 6 hours after application of the solution. Our findings confirm that isotonic and hypertonic saline solutions do not compromise epithelial barrier function in vitro but underscore the importance of examining safety and efficacy of over-the-counter wash solutions.

Actin-interacting protein 1 controls assembly and permeability of intestinal epithelial apical junctions.

Science.gov (United States)

Lechuga, Susana; Baranwal, Somesh; Ivanov, Andrei I

2015-05-01

Adherens junctions (AJs) and tight junctions (TJs) are crucial regulators of the integrity and restitution of the intestinal epithelial barrier. The structure and function of epithelial junctions depend on their association with the cortical actin cytoskeleton that, in polarized epithelial cells, is represented by a prominent perijunctional actomyosin belt. The assembly and stability of the perijunctional cytoskeleton is controlled by constant turnover (disassembly and reassembly) of actin filaments. Actin-interacting protein (Aip) 1 is an emerging regulator of the actin cytoskeleton, playing a critical role in filament disassembly. In this study, we examined the roles of Aip1 in regulating the structure and remodeling of AJs and TJs in human intestinal epithelium. Aip1 was enriched at apical junctions in polarized human intestinal epithelial cells and normal mouse colonic mucosa. Knockdown of Aip1 by RNA interference increased the paracellular permeability of epithelial cell monolayers, decreased recruitment of AJ/TJ proteins to steady-state intercellular contacts, and attenuated junctional reassembly in a calcium-switch model. The observed defects of AJ/TJ structure and functions were accompanied by abnormal organization and dynamics of the perijunctional F-actin cytoskeleton. Moreover, loss of Aip1 impaired the apico-basal polarity of intestinal epithelial cell monolayers and inhibited formation of polarized epithelial cysts in 3-D Matrigel. Our findings demonstrate a previously unanticipated role of Aip1 in regulating the structure and remodeling of intestinal epithelial junctions and early steps of epithelial morphogenesis. Copyright © 2015 the American Physiological Society.

Clinical value of the alveolar epithelial permeability in various pulmonary diseases

International Nuclear Information System (INIS)

Todisco, T.; Dottorini, M.; Rossi, F.; Polidori, A.; Bruni, B.; Iannacci, L.; Palumbo, R.; Fedeli, L.

1984-01-01

The authors have measured the pulmonary epithelial permeability in normals, smokers, ex-smokers and in various pulmonary diseases, using the sup(99m)Tc-DTPA monodisperse radioaerosol delivered by a newly designed nebulizer. Reference values for alveolar epithelial permeability were those of their own laboratory. Accelerated clearance of small idrophylic solutes from the lungs to the blood was found in smokers and in all the patients with idiopathic diffuse pulmonary fibrosis, chronic obstructive lung disease, congestive heart failure, acute viral pneumonia and adult respiratory distress syndrome. The greatest increase of alveolar epithelial clearance was found in the lung zone affected by the viral infection. The normal upper-lover lobe gradient of epithelial clearance was lost only in some patients. The increased permeability of the alveolar wall, although not specific, is characteristic and early feature of many acute and chronic pulmonary disease. For practical purposes, this parameter, rather than diagnostic, should be considered as a sensitive index of alveolar damage and repair, especially suitable for the follow-up of patients with spontaneous or therapeutic reversibility of parenchimal lung diseases. (orig.)

Lung epithelial permeability and inhaled furosemide. Added dimensions in asthmatics

International Nuclear Information System (INIS)

Bhure, U.N.; Bhure, S.U.; Bhatt, B.M.; Mistry, S.; Pednekar, S.J.; Chari, V.V.; Desai, S.A.; Joshi, J.M.; Paidhungat, A.J.

2009-01-01

Lung clearance rates of inhaled 99m Tc-diethylene-triamine-pentaacetic acid (DTPA) aerosols constitute a sensitive index to evaluate the permeability changes characteristic of airway epithelial damage. It was thought that edema of the airway wall which is reported in asthma could be relieved with a diuretic like furosemide, helping to relieve the symptoms. We intended to study the effect of inhaled furosemide on lung epithelial permeability in asthmatics and smokers with the help of 99m Tc-DTPA lung clearance test (LCT). The study included three groups (n=15), viz. normal healthy controls, asymptomatic chronic smokers, and chronic persistent asthmatics. Each subject underwent the LCT twice, baseline and post-furosemide (Lasix) study, within a week's interval. The post-furosemide study was carried out 15 min after inhalation of 10 mg of lasix. Lung epithelial permeability was determined in terms of clearance half-life (T 1/2 ). The baseline mean T 1/2 values for controls, smokers, and asthmatics were 50.95±16.58, 20.81±5.47, 24.06±6.19 min, respectively. Post-lasix T 1/2 values were 50.83±15.84, 20.70±5.65, 41.27±15.07 min, respectively. There was a significant difference (P<0.001) in baseline and post-lasix clearance values in asthmatics only. Baseline lung epithelial permeability was altered in smokers and asthmatics compared to the controls. Furosemide was effective only in asthmatics in reverting the permeability almost back to the normal range. Inhaled furosemide was effective even in moderate and severe asthmatics. Furosemide has multiple mechanisms of action. It possibly acts at bronchial level in view of the pathology in asthmatics lying in the airways. (author)

Alpha-Melanocyte Stimulating Hormone Protects against Cytokine-Induced Barrier Damage in Caco-2 Intestinal Epithelial Monolayers.

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Judit Váradi

Full Text Available Alpha-melanocyte-stimulating hormone (α-MSH is a potent anti-inflammatory peptide with cytoprotective effect in various tissues. The present investigation demonstrates the ability of α-MSH to interact with intestinal epithelial cell monolayers and mitigate inflammatory processes of the epithelial barrier. The protective effect of α-MSH was studied on Caco-2 human intestinal epithelial monolayers, which were disrupted by exposure to tumor necrosis factor-α and interleukin-1β. The barrier integrity was assessed by measuring transepithelial electric resistance (TEER and permeability for marker molecules. Caco-2 monolayers were evaluated by immunohistochemistry for expression of melanocortin-1 receptor and tight junction proteins ZO-1 and claudin-4. The activation of nuclear factor kappa beta (NF-κB was detected by fluorescence microscopy and inflammatory cytokine expression was assessed by flow cytometric bead array cytokine assay. Exposure of Caco-2 monolayers to proinflammatory cytokines lowered TEER and increased permeability for fluorescein and albumin, which was accompanied by changes in ZO-1 and claudin-4 immunostaining. α-MSH was able to prevent inflammation-associated decrease of TEER in a dose-dependent manner and reduce the increased permeability for paracellular marker fluorescein. Further immunohistochemistry analysis revealed proinflammatory cytokine induced translocation of the NF-κB p65 subunit into Caco-2 cell nuclei, which was inhibited by α-MSH. As a result the IL-6 and IL-8 production of Caco-2 monolayers were also decreased with different patterns by the addition of α-MSH to the culture medium. In conclusion, Caco-2 cells showed a positive immunostaining for melanocortin-1 receptor and α-MSH protected Caco-2 cells against inflammatory barrier dysfunction and inflammatory activation induced by tumor necrosis factor-α and interleukin-1β cytokines.

Permeable reactive barriers for pollutant removal from groundwater

International Nuclear Information System (INIS)

Simon, F.G.; Meggyes, T.

2001-01-01

The removal of pollutants from the groundwater using permeable reactive barriers is a novel in-situ groundwater remediation technology. The most relevant decontamination processes used are chemical reduction, oxidation, precipitation and sorption, for which examples are given. Some common organic pollutants are halogenated hydrocarbons, aromatic and nitroaromatic compounds which can be treated in reactive barriers successfully. Lead, chromium and, in particular, uranium are dealt with in great detail among inorganic pollutants because of their occurrence in many European countries. Construction methods for cut-off walls and reactive barriers exhibit similar features. Apart from conventional methods, drilling, deep soil mixing, jet technology, arrays of wells, injected systems and biobarriers are applied to construct permeable reactive barriers. Permeable reactive barriers bear great potential for the future in remediation engineering. (orig.)

Knockout of MIMP protein in lactobacillus plantarum lost its regulation of intestinal permeability on NCM460 epithelial cells through the zonulin pathway.

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Liu, Zhihua; Kang, Liang; Li, Chao; Tong, Chao; Huang, Meijin; Zhang, Xingwei; Huang, Nanqi; Moyer, Mary Pat; Qin, Huanlong; Wang, Jianping

2014-10-03

Previous studies indicated that the micro integral membrane protein located within the media place of the integral membrane protein of Lactobacillus plantarum CGMCC 1258 had protective effects against the intestinal epithelial injury. In our study, we mean to establish micro integral membrane protein -knockout Lactobacillus plantarum (LPKM) to investigate the change of its protective effects and verify the role of micro integral membrane protein on protection of normal intestinal barrier function. Binding assay and intestinal permeability were performed to verify the protective effects of micro integral membrane protein on intestinal permeability in vitro and in vivo. Molecular mechanism was also determined as the zonulin pathway. Clinical data were also collected for further verification of relationship between zonulin level and postoperative septicemia. LPKM got decreased inhibition of EPEC adhesion to NCM460 cells. LPKM had lower ability to alleviate the decrease of intestinal permeability induced by enteropathogenic-e.coli, and prevent enteropathogenic-e.coli -induced increase of zonulin expression. Overexpression of zonulin lowered the intestinal permeability regulated by Lactobacillus plantarum. There was a positive correlation between zonulin level and postoperative septicemia. Therefore, micro integral membrane protein could be necessary for the protective effects of Lactobacillus plantarum on intestinal barrier. MIMP might be a positive factor for Lactobacillus plantarum to protect the intestinal epithelial cells from injury, which could be related to the zonulin pathway.

Potential in vitro model for testing the effect of exposure to nanoparticles on the lung alveolar epithelial barrier

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Raymond Derk

2015-03-01

Full Text Available Pulmonary barrier function plays a pivotal role in protection from inhaled particles. However, some nano-scaled particles, such as carbon nanotubes (CNT, have demonstrated the ability to penetrate this barrier in animal models, resulting in an unusual, rapid interstitial fibrosis. To delineate the underlying mechanism and specific bio-effect of inhaled nanoparticles in respiratory toxicity, models of lung epithelial barriers are required that allow accurate representation of in vivo systems; however, there is currently a lack of consistent methods to do so. Thus, this work demonstrates a well-characterized in vitro model of pulmonary barrier function using Calu-3 cells, and provides the experimental conditions required for achieving tight junction complexes in cell culture, with trans-epithelial electrical resistance measurement used as a biosensor for proper barrier formation and integrity. The effects of cell number and serum constituents have been examined and we found that changes in each of these parameters can greatly affect barrier formation. Our data demonstrate that use of 5.0 × 104 Calu-3 cells/well in the Transwell cell culture system, with 10% serum concentrations in culture media is optimal for assessing epithelial barrier function. In addition, we have utilized CNT exposure to analyze the dose-, time-, and nanoparticle property-dependent alterations of epithelial barrier permeability as a means to validate this model. Such high throughput in vitro cell models of the epithelium could be used to predict the interaction of other nanoparticles with lung epithelial barriers to mimic respiratory behavior in vivo, thus providing essential tools and bio-sensing techniques that can be uniformly employed.

Molecular Pathophysiology of Epithelial Barrier Dysfunction in Inflammatory Bowel Diseases

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Jessica Y. Lee

2018-03-01

Full Text Available Over the years, the scientific community has explored myriads of theories in search of the etiology and a cure for inflammatory bowel disease (IBD. The cumulative evidence has pointed to the key role of the intestinal barrier and the breakdown of these mechanisms in IBD. More and more scientists and clinicians are embracing the concept of the impaired intestinal epithelial barrier and its role in the pathogenesis and natural history of IBD. However, we are missing a key tool that bridges these scientific insights to clinical practice. Our goal is to overcome the limitations in understanding the molecular physiology of intestinal barrier function and develop a clinical tool to assess and quantify it. This review article explores the proteins in the intestinal tissue that are pivotal in regulating intestinal permeability. Understanding the molecular pathophysiology of impaired intestinal barrier function in IBD may lead to the development of a biochemical method of assessing intestinal tissue integrity which will have a significant impact on the development of novel therapies targeting the intestinal mucosa.

microRNA-4516 Contributes to Different Functions of Epithelial Permeability Barrier by Targeting Poliovirus Receptor Related Protein 1 in Enterovirus 71 and Coxsackievirus A16 Infections

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Yajie Hu

2018-04-01

Full Text Available Enterovirus 71 (EV-A71 and coxsackievirus A16 (CV-A16 remain the predominant etiological agents of hand, foot, and mouth disease (HFMD. The clinical manifestations caused by the two viruses are obviously different. CV-A16 usually triggers a repeated infection, and airway epithelial integrity is often the potential causative factor of respiratory repeated infections. Our previous studies have demonstrated that there were some differentially expressed miRNAs involved in the regulation of adhesion function of epithelial barrier in EV-A71 and CV-A16 infections. In this study, we compared the differences between EV-A71 and CV-A16 infections on the airway epithelial barrier function in human bronchial epithelial (16HBE cells and further screened the key miRNA which leaded to the formation of these differences. Our results showed that more rapid proliferation, more serious destruction of 16HBE cells permeability, more apoptosis and disruption of intercellular adhesion-associated molecules were found in CV-A16 infection as compared to EV-A71 infection. Furthermore, we also identified that microRNA-4516 (miR-4516, which presented down-regulation in EV-A71 infection and up-regulation in CV-A16 infection was an important regulator of intercellular junctions by targeting Poliovirus receptor related protein 1(PVRL1. The expressions of PVRL1, claudin4, ZO-1 and E-cadherin in CV-A16-infected cells were significantly less than those in EV-A71-infected cells, while the expressions of these proteins were subverted when pre-treated with miR-4516-overexpression plasmid in EV-A71 infected and miR-4516-knockdown plasmid in CV-A16 infected 16HBE cells. Thus, these data suggested that the opposite expression of miR-4516 in EV-A71 and CV-A16 infections might be the initial steps leading to different epithelial impairments of 16HBE cells by destroying intercellular adhesion, which finally resulted in different outcomes of EV-A71 and CV-A16 infections.

Extracorporeal membrane oxygenation causes loss of intestinal epithelial barrier in the newborn piglet.

Science.gov (United States)

Kurundkar, Ashish R; Killingsworth, Cheryl R; McIlwain, R Britt; Timpa, Joseph G; Hartman, Yolanda E; He, Dongning; Karnatak, Rajendra K; Neel, Mary L; Clancy, John P; Anantharamaiah, G M; Maheshwari, Akhil

2010-08-01

Extracorporeal membrane oxygenation (ECMO) is an important life-support system used in neonates and young children with intractable cardiorespiratory failure. In this study, we used our porcine neonatal model of venoarterial ECMO to investigate whether ECMO causes gut barrier dysfunction. We subjected 3-wk-old previously healthy piglets to venoarterial ECMO for up to 8 h and evaluated gut mucosal permeability, bacterial translocation, plasma levels of bacterial products, and ultrastructural changes in gut epithelium. We also measured plasma lipopolysaccharide (LPS) levels in a small cohort of human neonates receiving ECMO. In our porcine model, ECMO caused a rapid increase in gut mucosal permeability within the first 2 h of treatment, leading to a 6- to 10-fold rise in circulating bacterial products. These changes in barrier function were associated with cytoskeletal condensation in epithelial cells, which was explained by phosphorylation of a myosin II regulatory light chain. In support of these findings, we also detected elevated plasma LPS levels in human neonates receiving ECMO, indicating a similar loss of gut barrier function in these infants. On the basis of these data, we conclude that ECMO is an independent cause of gut barrier dysfunction and bacterial translocation may be an important contributor to ECMO-related inflammation.

Type 2 innate lymphoid cells disrupt bronchial epithelial barrier integrity by targeting tight junctions through IL-13 in asthmatic patients.

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Sugita, Kazunari; Steer, Catherine A; Martinez-Gonzalez, Itziar; Altunbulakli, Can; Morita, Hideaki; Castro-Giner, Francesc; Kubo, Terufumi; Wawrzyniak, Paulina; Rückert, Beate; Sudo, Katsuko; Nakae, Susumu; Matsumoto, Kenji; O'Mahony, Liam; Akdis, Mübeccel; Takei, Fumio; Akdis, Cezmi A

2018-01-01

Bronchial epithelial barrier leakiness and type 2 innate lymphoid cells (ILC2s) have been separately linked to asthma pathogenesis; however, the influence of ILC2s on the bronchial epithelial barrier has not been investigated previously. We investigated the role of ILC2s in the regulation of bronchial epithelial tight junctions (TJs) and barrier function both in bronchial epithelial cells of asthmatic patients and healthy subjects and general innate lymphoid cell- and ILC2-deficient mice. Cocultures of human ILC2s and bronchial epithelial cells were used to determine transepithelial electrical resistance, paracellular flux, and TJ mRNA and protein expressions. The effect of ILC2s on TJs was examined by using a murine model of IL-33-induced airway inflammation in wild-type, recombination-activating gene 2 (Rag2) -/- , Rag2 -/- Il2rg -/- , and Rora sg/sg mice undergoing bone marrow transplantation to analyze the in vivo relevance of barrier disruption by ILC2s. ILC2s significantly impaired the epithelial barrier, as demonstrated by reduced transepithelial electrical resistance and increased fluorescein isothiocyanate-dextran permeability in air-liquid interface cultures of human bronchial epithelial cells. This was in parallel to decreased mRNAs and disrupted protein expression of TJ proteins and was restored by neutralization of IL-13. Intranasal administration of recombinant IL-33 to wild-type and Rag2 -/- mice lacking T and B cells triggered TJ disruption, whereas Rag2 -/- Il2rg -/- and Rora sg/sg mice undergoing bone marrow transplantation that lack ILC2s did not show any barrier leakiness. Direct nasal administration of IL-13 was sufficient to induce deficiency in the TJ barrier in the bronchial epithelium of mice in vivo. These data highlight an essential mechanism in asthma pathogenesis by demonstrating that ILC2s are responsible for bronchial epithelial TJ barrier leakiness through IL-13. Copyright © 2017 American Academy of Allergy, Asthma & Immunology

Exploiting the Gastric Epithelial Barrier: Helicobacter pylori's Attack on Tight and Adherens Junctions.

Science.gov (United States)

Backert, Steffen; Schmidt, Thomas P; Harrer, Aileen; Wessler, Silja

2017-01-01

Highly organized intercellular tight and adherens junctions are crucial structural components for establishing and maintenance of epithelial barrier functions, which control the microbiota and protect against intruding pathogens in humans. Alterations in these complexes represent key events in the development and progression of multiple infectious diseases as well as various cancers. The gastric pathogen Helicobacter pylori exerts an amazing set of strategies to manipulate these epithelial cell-to-cell junctions, which are implicated in changing cell polarity, migration and invasive growth as well as pro-inflammatory and proliferative responses. This chapter focuses on the H. pylori pathogenicity factors VacA, CagA, HtrA and urease, and how they can induce host cell signaling involved in altering cell-to-cell permeability. We propose a stepwise model for how H. pylori targets components of tight and adherens junctions in order to disrupt the gastric epithelial cell layer, giving fresh insights into the pathogenesis of this important bacterium.

Conjugated primary bile salts reduce permeability of endotoxin through bacteria-stimulated intestinal epithelial cells and synergize with lecithin in suppression of inflammatory cytokine production

DEFF Research Database (Denmark)

Parlesak, Alexandr; Schaeckeler, Simone; Moser, Lydia

2007-01-01

: The effect of CPBS (0.5 mM and 1.5 mM), phosphatidylcholine(0.38 mM), and human bile (0.5% vol/vol) on the barrier function was assessed by the measurement of transepithelial electrical resistance, by endotoxin permeability through the intestinal epithelial cell layer, and by basolateral cytokine enzyme...

Groundwater protection from cadmium contamination by permeable reactive barriers

Energy Technology Data Exchange (ETDEWEB)

Di Natale, F. [Dipartimento di Ingegneria chimica, Universita di Federico II, P.le Tecchio, 80-80125 Naples (Italy)], E-mail: fdinatal@unina.it; Di Natale, M.; Greco, R. [Centro Interdipartimentale di Ricerca in Ingegneria Ambientale (CIRIAM), Dipartimento di Ingegneria Civile, Seconda Universita di Napoli, via Roma 29-81031 Aversa (Caserta) (Italy); Lancia, A. [Dipartimento di Ingegneria chimica, Universita di Federico II, P.le Tecchio, 80-80125 Naples (Italy); Laudante, C.; Musmarra, D. [Centro Interdipartimentale di Ricerca in Ingegneria Ambientale (CIRIAM), Dipartimento di Ingegneria Civile, Seconda Universita di Napoli, via Roma 29-81031 Aversa (Caserta) (Italy)

2008-12-30

This work studies the reliability of an activated carbon permeable reactive barrier in removing cadmium from a contaminated shallow aquifer. Laboratory tests have been performed to characterize the equilibrium and kinetic adsorption properties of the activated carbon in cadmium-containing aqueous solutions. A 2D numerical model has been used to describe pollutant transport within a groundwater and the pollutant adsorption on the permeable adsorbing barrier (PRB). In particular, it has been considered the case of a permeable adsorbing barrier (PAB) used to protect a river from a Cd(II) contaminated groundwater. Numerical results show that the PAB can achieve a long-term efficiency by preventing river pollution for several months.

Tumor necrosis factor alpha increases epithelial barrier permeability by disrupting tight junctions in Caco-2 cells

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W. Cui

2010-04-01

Full Text Available The objectives of this study were to determine the effect of tumor necrosis factor alpha (TNF-α on intestinal epithelial cell permeability and the expression of tight junction proteins. Caco-2 cells were plated onto Transwell® microporous filters and treated with TNF-α (10 or 100 ng/mL for 0, 4, 8, 16, or 24 h. The transepithelial electrical resistance and the mucosal-to-serosal flux rates of the established paracellular marker Lucifer yellow were measured in filter-grown monolayers of Caco-2 intestinal cells. The localization and expression of the tight junction protein occludin were detected by immunofluorescence and Western blot analysis, respectively. SYBR-Green-based real-time PCR was used to measure the expression of occludin mRNA. TNF-α treatment produced concentration- and time-dependent decreases in Caco-2 transepithelial resistance and increases in transepithelial permeability to the paracellular marker Lucifer yellow. Western blot results indicated that TNF-α decreased the expression of phosphorylated occludin in detergent-insoluble fractions but did not affect the expression of non-phosphorylated occludin protein. Real-time RT-PCR data showed that TNF-α did not affect the expression of occludin mRNA. Taken together, our data demonstrate that TNF-α increases Caco-2 monolayer permeability, decreases occludin protein expression and disturbs intercellular junctions.

Boswellia serrata Preserves Intestinal Epithelial Barrier from Oxidative and Inflammatory Damage.

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Daniela Catanzaro

Full Text Available Aminosalicylates, corticosteroids and immunosuppressants are currently the therapeutic choices in inflammatory bowel diseases (IBD, however, with limited remission and often serious side effects. Meanwhile complementary and alternative medicine (CAM use is increasing, particularly herbal medicine. Boswellia serrata is a traditional Ayurvedic remedy with anti-inflammatory properties, of interest for its usefulness in IBDs. The mechanism of this pharmacological potential of Boswellia serrata was investigated in colonic epithelial cell monolayers exposed to H2O2 or INF-γ+TNF-α, chosen as in vitro experimental model of intestinal inflammation. The barrier function was evaluated by the transepithelial electrical resistance (TEER and paracellular permeability assay, and by the tight junction proteins (zonula occludens-1, ZO-1 and occludin immunofluorescence. The expression of phosphorylated NF-κB and reactive oxygen species (ROS generation were determined by immunoblot and cytofluorimetric assay, respectively. Boswellia serrata oleo-gum extract (BSE and its pure derivative acetyl-11-keto-β-boswellic acid (AKBA, were tested at 0.1-10 μg/ml and 0.027 μg/ml, respectively. BSE and AKBA safety was demonstrated by no alteration of intestinal cell viability and barrier function and integrity biomarkers. H2O2 or INF-γ+TNF-α treatment of Caco-2 cell monolayers significantly reduced TEER, increased paracellular permeability and caused the disassembly of tight junction proteins occludin and ZO-1. BSE and AKBA pretreatment significantly prevented functional and morphological alterations and also the NF-κB phosphorylation induced by the inflammatory stimuli. At the same concentrations BSE and AKBA counteracted the increase of ROS caused by H2O2 exposure. Data showed the positive correlation of the antioxidant activity with the mechanism involved in the physiologic maintenance of the integrity and function of the intestinal epithelium. This study

Hydraulic performance of permeable barriers for in situ treatment of contaminated groundwater

International Nuclear Information System (INIS)

Smyth, D.J.A.; Shikaze, S.G.; Cherry, J.A.

1997-01-01

The passive interception and in situ treatment of dissolved contaminants in groundwater by permeable reactive barriers has recently gained favor at an increasing number of sites as an alternative to conventional approaches to groundwater remediation such as the pump-and-treat method. Permeable reactive barriers have two essential functions. The first is that the barriers must be installed in a position such that all of the plume passes through the reactive system. The second function is to achieve acceptable treatment of the contamination by physical, chemical or biological means within or downgradient of the barrier. In this paper, issues associated with the hydraulic performance of permeable reaction barriers are evaluated using a three-dimensional groundwater flow model. The efficiency of plume capture by permeable wall and funnel-and-gate systems is examined for some generic and for site-specific hydrogeologic systems. The results have important implications to decisions pertaining to the selection, design and installation of permeable reactive barrier systems

Defects in small intestinal epithelial barrier function and morphology associated with peri-weaning failure to thrive syndrome (PFTS) in swine.

Science.gov (United States)

Moeser, Adam J; Borst, Luke B; Overman, Beth L; Pittman, Jeremy S

2012-10-01

The objective of this study was to investigate intestinal function and morphology associated with peri-weaning failure to thrive syndrome (PFTS) in swine. Jejunum and distal ileum from control and pigs exhibiting PFTS was harvested at weaning, 4 and 11 days post-weaning (PW) for intestinal barrier function studies and histological analyses (n=6 pigs per group). Marked disturbances in intestinal barrier function was observed in PFTS pigs, compared with controls, indicated by lower (p<0.05) TER and increased (p<0.01) permeability to FITC dextran (4 kDa). Intestines from weaned pigs, subjected to a 4-day fast, exhibited minor disturbances in intestinal barrier function. Villus atrophy and crypt hyperplasia were observed in the PFTS intestine compared with control and fasted pigs. These data demonstrate that PFTS is associated with profound disturbances in intestinal epithelial barrier function and alterations in mucosal and epithelial morphology in which anorexia is not the sole factor. Copyright © 2012 Elsevier Ltd. All rights reserved.

Heavy Cigarette Smokers in a Chinese Population Display a Compromised Permeability Barrier

Science.gov (United States)

Xin, Shujun; Ye, Li; Lv, Chengzhi; Elias, Peter M.

2016-01-01

Cigarette smoking is associated with various cutaneous disorders with defective permeability. Yet, whether cigarette smoking influences epidermal permeability barrier function is largely unknown. Here, we measured skin biophysical properties, including permeability barrier homeostasis, stratum corneum (SC) integrity, SC hydration, skin surface pH, and skin melanin/erythema index, in cigarette smokers. A total of 99 male volunteers were enrolled in this study. Smokers were categorized as light-to-moderate (hydration and skin melanin/erythema index on the dorsal hand, forehead, and cheek. Basal transepidermal water loss (TEWL) and barrier recovery rates were assessed on the forearm. A Skin-pH-Meter pH900 was used to measure skin surface pH. Our results showed that heavy cigarette smokers exhibited delayed barrier recovery after acute abrogation (1.02% ± 13.06 versus 16.48% ± 6.07), and barrier recovery rates correlated negatively with the number of daily cigarettes consumption (p = 0.0087). Changes in biophysical parameters in cigarette smokers varied with body sites. In conclusion, heavy cigarette smokers display compromised permeability barrier homeostasis, which could contribute, in part, to the increased prevalence of certain cutaneous disorders characterized by defective permeability. Thus, improving epidermal permeability barrier should be considered for heavy cigarette smokers. PMID:27437403

Review of potential subsurface permeable barrier emplacement and monitoring technologies

International Nuclear Information System (INIS)

Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.; Schwarz, R.M.; Cantrell, K.J.; Phillips, S.J.

1994-02-01

This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, or excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods

Integrated Stress Response Mediates Epithelial Injury in Mechanical Ventilation.

Science.gov (United States)

Dolinay, Tamas; Himes, Blanca E; Shumyatcher, Maya; Lawrence, Gladys Gray; Margulies, Susan S

2017-08-01

Ventilator-induced lung injury (VILI) is a severe complication of mechanical ventilation that can lead to acute respiratory distress syndrome. VILI is characterized by damage to the epithelial barrier with subsequent pulmonary edema and profound hypoxia. Available lung-protective ventilator strategies offer only a modest benefit in preventing VILI because they cannot impede alveolar overdistension and concomitant epithelial barrier dysfunction in the inflamed lung regions. There are currently no effective biochemical therapies to mitigate injury to the alveolar epithelium. We hypothesize that alveolar stretch activates the integrated stress response (ISR) pathway and that the chemical inhibition of this pathway mitigates alveolar barrier disruption during stretch and mechanical ventilation. Using our established rat primary type I-like alveolar epithelial cell monolayer stretch model and in vivo rat mechanical ventilation that mimics the alveolar overdistension seen in acute respiratory distress syndrome, we studied epithelial responses to mechanical stress. Our studies revealed that the ISR signaling pathway is a key modulator of epithelial permeability. We show that prolonged epithelial stretch and injurious mechanical ventilation activate the ISR, leading to increased alveolar permeability, cell death, and proinflammatory signaling. Chemical inhibition of protein kinase RNA-like endoplasmic reticulum kinase, an upstream regulator of the pathway, resulted in decreased injury signaling and improved barrier function after prolonged cyclic stretch and injurious mechanical ventilation. Our results provide new evidence that therapeutic targeting of the ISR can mitigate VILI.

Primary human polarized small intestinal epithelial barriers respond differently to a hazardous and an innocuous protein.

Science.gov (United States)

Eaton, A D; Zimmermann, C; Delaney, B; Hurley, B P

2017-08-01

An experimental platform employing human derived intestinal epithelial cell (IEC) line monolayers grown on permeable Transwell ® filters was previously investigated to differentiate between hazardous and innocuous proteins. This approach was effective at distinguishing these types of proteins and perturbation of monolayer integrity, particularly transepithelial electrical resistance (TEER), was the most sensitive indicator. In the current report, in vitro indicators of monolayer integrity, cytotoxicity, and inflammation were evaluated using primary (non-transformed) human polarized small intestinal epithelial barriers cultured on Transwell ® filters to compare effects of a hazardous protein (Clostridium difficile Toxin A [ToxA]) and an innocuous protein (bovine serum albumin [BSA]). ToxA exerted a reproducible decrease on barrier integrity at doses comparable to those producing effects observed from cell line-derived IEC monolayers, with TEER being the most sensitive indicator. In contrast, BSA, tested at concentrations substantially higher than ToxA, did not cause changes in any of the tested variables. These results demonstrate a similarity in response to certain proteins between cell line-derived polarized IEC models and a primary human polarized small intestinal epithelial barrier model, thereby reinforcing the potential usefulness of cell line-derived polarized IECs as a valid experimental platform to differentiate between hazardous and non-hazardous proteins. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Interleukin-4 and interleukin-13 compromise the sinonasal epithelial barrier and perturb intercellular junction protein expression.

Science.gov (United States)

Wise, Sarah K; Laury, Adrienne M; Katz, Elizabeth H; Den Beste, Kyle A; Parkos, Charles A; Nusrat, Asma

2014-05-01

Altered expression of epithelial intercellular junction proteins has been observed in sinonasal biopsies from nasal polyps and epithelial layers cultured from nasal polyp patients. These alterations comprise a "leaky" epithelial barrier phenotype. We hypothesize that T helper 2 (Th2) cytokines interleukin (IL)-4 and IL-13 modulate epithelial junction proteins, thereby contributing to the leaky epithelial barrier. Differentiated primary sinonasal epithelial layers cultured at the air-liquid interface were exposed to IL-4, IL-13, and controls for 24 hours at 37°C. Epithelial resistance measurements were taken every 4 hours during cytokine exposure. Western blot and immunofluorescence staining/confocal microscopy were used to assess changes in a panel of tight and adherens junction proteins. Western blot densitometry was quantified with image analysis. IL-4 and IL-13 exposure resulted in a mean decrease in transepithelial resistance at 24 hours to 51.6% (n = 6) and 68.6% (n = 8) of baseline, respectively. Tight junction protein junctional adhesion molecule-A (JAM-A) expression decreased 42.2% with IL-4 exposure (n = 9) and 37.5% with IL-13 exposure (n = 9). Adherens junction protein E-cadherin expression decreased 35.3% with IL-4 exposure (n = 9) and 32.9% with IL-13 exposure (n = 9). Tight junction protein claudin-2 showed more variability but had a trend toward higher expression with Th2 cytokine exposure. There were no appreciable changes in claudin-1, occludin, or zonula occludens-1 (ZO-1) with IL-4 or IL-13 exposure. Sinonasal epithelial exposure to Th2 cytokines IL-4 and IL-13 results in alterations in intercellular junction proteins, reflecting increased epithelial permeability. Such changes may explain some of the phenotypic manifestations of Th2-mediated sinonasal disease, such as edema, nasal discharge, and environmental reactivity. © 2014 ARS-AAOA, LLC.

IL-4 and IL-13 Compromise the Sinonasal Epithelial Barrier and Perturb Intercellular Junction Protein Expression

Science.gov (United States)

Wise, Sarah K.; Laury, Adrienne M.; Katz, Elizabeth H.; Den Beste, Kyle A.; Parkos, Charles A.; Nusrat, Asma

2014-01-01

Introduction Altered expression of epithelial intercellular junction proteins has been observed in sinonasal biopsies from nasal polyps and epithelial layers cultured from nasal polyp patients. These alterations comprise a “leaky” epithelial barrier phenotype. We hypothesize that Th2 cytokines IL-4 and IL-13 modulate epithelial junction proteins thereby contributing to the leaky epithelial barrier. Methods Differentiated primary sinonasal epithelial layers cultured at the air-liquid interface were exposed to IL-4, IL-13, and controls for 24 hours at 37°C. Epithelial resistance measurements were taken every 4 hours during cytokine exposure. Western blot and immunofluorescence staining/confocal microscopy were used to assess changes in a panel of tight and adherens junction proteins. Western blot densitometry was quantified with image analysis. Results IL-4 and IL-13 exposure resulted in a mean decrease in transepithelial resistance at 24 hours to 51.6% (n=6) and 68.6% (n=8) of baseline, respectively. Tight junction protein JAM-A expression decreased 42.2% with IL-4 exposure (n=9) and 37.5% with IL-13 exposure (n=9). Adherens junction protein E-cadherin expression decreased 35.3% with IL-4 exposure (n=9) and 32.9% with IL-13 exposure (n=9). Tight junction protein claudin-2 showed more variability but had a trend toward higher expression with Th2 cytokine exposure. There were no appreciable changes in claudin-1, occludin, or ZO-1 with IL-4 or IL-13 exposure. Conclusion Sinonasal epithelial exposure to Th2 cytokines IL-4 and IL-13 results in alterations in intercellular junction proteins, reflecting increased epithelial permeability. Such changes may explain some of the phenotypic manifestations of Th2-mediated sinonasal disease, such as edema, nasal discharge, and environmental reactivity. PMID:24510479

Vocal Fold Epithelial Barrier in Health and Injury A Research Review

Science.gov (United States)

Levendoski, Elizabeth Erickson; Leydon, Ciara; Thibeault, Susan L.

2015-01-01

Purpose Vocal fold epithelium is composed of layers of individual epithelial cells joined by junctional complexes constituting a unique interface with the external environment. This barrier provides structural stability to the vocal folds and protects underlying connective tissue from injury while being nearly continuously exposed to potentially hazardous insults including environmental or systemic-based irritants such as pollutants and reflux, surgical procedures, and vibratory trauma. Small disruptions in the epithelial barrier may have a large impact on susceptibility to injury and overall vocal health. The purpose of this article is to provide a broad-based review of our current knowledge of the vocal fold epithelial barrier. Methods A comprehensive review of the literature was conducted. Details of the structure of the vocal fold epithelial barrier are presented and evaluated in the context of function in injury and pathology. The importance of the epithelial-associated vocal fold mucus barrier is also introduced. Results/Conclusions Information presented in this review is valuable for clinicians and researchers as it highlights the importance of this understudied portion of the vocal folds to overall vocal health and disease. Prevention and treatment of injury to the epithelial barrier is a significant area awaiting further investigation. PMID:24686981

Celiac Disease: Role of the Epithelial BarrierSummary

Directory of Open Access Journals (Sweden)

Michael Schumann

2017-03-01

Full Text Available In celiac disease (CD a T-cell–mediated response to gluten is mounted in genetically predisposed individuals, resulting in a malabsorptive enteropathy histologically highlighted by villous atrophy and crypt hyperplasia. Recent data point to the epithelial layer as an under-rated hot spot in celiac pathophysiology to date. This overview summarizes current functional and genetic evidence on the role of the epithelial barrier in CD, consisting of the cell membranes and the apical junctional complex comprising sealing as well as ion and water channel-forming tight junction proteins and the adherens junction. Moreover, the underlying mechanisms are discussed, including apoptosis of intestinal epithelial cells, biology of intestinal stem cells, alterations in the apical junctional complex, transcytotic uptake of gluten peptides, and possible implications of a defective epithelial polarity. Current research is directed toward new treatment options for CD that are alternatives or complementary therapeutics to a gluten-free diet. Thus, strategies to target an altered epithelial barrier therapeutically also are discussed. Keywords: Celiac Sprue, Gluten-Sensitive Enteropathy, Tight Junction, Epithelial Polarity, Partitioning-Defective Proteins, α-Gliadin 33mer

A framework for understanding semi-permeable barrier effects on migratory ungulates

Science.gov (United States)

Sawyer, Hall; Kauffman, Matthew J.; Middleton, Arthur D.; Morrison, Thomas A.; Nielson, Ryan M.; Wyckoff, Teal B.

2013-01-01

1. Impermeable barriers to migration can greatly constrain the set of possible routes and ranges used by migrating animals. For ungulates, however, many forms of development are semi-permeable, and making informed management decisions about their potential impacts to the persistence of migration routes is difficult because our knowledge of how semi-permeable barriers affect migratory behaviour and function is limited. 2. Here, we propose a general framework to advance the understanding of barrier effects on ungulate migration by emphasizing the need to (i) quantify potential barriers in terms that allow behavioural thresholds to be considered, (ii) identify and measure behavioural responses to semi-permeable barriers and (iii) consider the functional attributes of the migratory landscape (e.g. stopovers) and how the benefits of migration might be reduced by behavioural changes. 3. We used global position system (GPS) data collected from two subpopulations of mule deer Odocoileus hemionus to evaluate how different levels of gas development influenced migratory behaviour, including movement rates and stopover use at the individual level, and intensity of use and width of migration route at the population level. We then characterized the functional landscape of migration routes as either stopover habitat or movement corridors and examined how the observed behavioural changes affected the functionality of the migration route in terms of stopover use. 4. We found migratory behaviour to vary with development intensity. Our results suggest that mule deer can migrate through moderate levels of development without any noticeable effects on migratory behaviour. However, in areas with more intensive development, animals often detoured from established routes, increased their rate of movement and reduced stopover use, while the overall use and width of migration routes decreased. 5. Synthesis and applications. In contrast to impermeable barriers that impede animal movement

Drug-permeability and transporter assays in Caco-2 and MDCK cell lines.

Science.gov (United States)

Volpe, Donna A

2011-12-01

The human colon adenocarcinoma Caco-2 and Madin-Darby canine kidney epithelial cell lines provide in vitro tools to assess a drug's permeability and transporter interactions during discovery and development. The cells, when cultured on semiporous filters, form confluent monolayers that model the intestinal epithelial barrier for permeability, transporter and drug-interaction assays. The applications of these assays in pharmaceutical research include qualitative prediction and ranking of absorption, determining mechanism(s) of permeability, formulation effects on drug permeability, and the potential for transporter-mediated drug-drug interactions. This review focuses on recent examples of Caco-2 and Madin-Darby canine kidney cells assays for drug permeability including transfected and knock-down cells, miniaturization and automation, and assay combinations to better understand and predict intestinal drug absorption.

Comparative effects of metal oxide nanoparticles on human airway epithelial cells and macrophages

International Nuclear Information System (INIS)

Rotoli, Bianca Maria; Bussolati, Ovidio; Costa, Anna Luisa; Blosi, Magda; Di Cristo, Luisana; Zanello, Pier Paolo; Bianchi, Massimiliano G.; Visigalli, Rossana; Bergamaschi, Enrico

2012-01-01

Among nanomaterials of industrial relevance, metal-based nanoparticles (NPs) are widely used, but their effects on airway cells are relatively poorly characterized. To compare the effects of metal NPs on cells representative of the lung-blood barrier, Calu-3 epithelial cells and Raw264.7 macrophages were incubated with three industrially relevant preparations of TiO 2 NPs (size range 4–33 nm), two preparations of CeO 2 NPs (9–36 nm) and CuO NPs (25 nm). While Raw264.7 were grown on standard plasticware, Calu-3 cells were seeded on permeable filters, where they form a high-resistance monolayer, providing an in vitro model of the airway barrier. Metal NPs, obtained from industrial sources, were characterized under the conditions adopted for the biological tests. Cytotoxicity was assessed with resazurin method in both epithelial and macrophage cells, while epithelial barrier permeability was monitored measuring the trans-epithelial electrical resistance (TEER). In macrophages, titania and ceria had no significant effect on viability in the whole range of nominal doses tested (15–240 μg/cm 2 of monolayer), while CuO NPs produced a marked viability loss. Moreover, only CuO NPs, but not the other NPs, lowered TEER of Calu-3 monolayers, pointing to the impairment of the epithelial barrier. TEER decreased by 30 % at the dose of 10 μg/cm 2 of CuO NPs, compared to untreated control, and was abolished at doses ≥80 μg/cm 2 , in strict correlation with changes in cell viability. These results indicate that (1) CuO NPs increase airway epithelium permeability even at relatively low doses and are significantly toxic for macrophages and airway epithelial cells, likely through the release of Cu ions in the medium; (2) TiO 2 and CeO 2 NPs do not affect TEER and exhibit little acute toxicity for airway epithelial cells and macrophages; and (3) TEER measurement can provide a simple method to assess the impairment of in vitro airway epithelial barrier model by manufactured

Comparative effects of metal oxide nanoparticles on human airway epithelial cells and macrophages

Science.gov (United States)

Rotoli, Bianca Maria; Bussolati, Ovidio; Costa, Anna Luisa; Blosi, Magda; Di Cristo, Luisana; Zanello, Pier Paolo; Bianchi, Massimiliano G.; Visigalli, Rossana; Bergamaschi, Enrico

2012-09-01

Among nanomaterials of industrial relevance, metal-based nanoparticles (NPs) are widely used, but their effects on airway cells are relatively poorly characterized. To compare the effects of metal NPs on cells representative of the lung-blood barrier, Calu-3 epithelial cells and Raw264.7 macrophages were incubated with three industrially relevant preparations of TiO2 NPs (size range 4-33 nm), two preparations of CeO2 NPs (9-36 nm) and CuO NPs (25 nm). While Raw264.7 were grown on standard plasticware, Calu-3 cells were seeded on permeable filters, where they form a high-resistance monolayer, providing an in vitro model of the airway barrier. Metal NPs, obtained from industrial sources, were characterized under the conditions adopted for the biological tests. Cytotoxicity was assessed with resazurin method in both epithelial and macrophage cells, while epithelial barrier permeability was monitored measuring the trans-epithelial electrical resistance (TEER). In macrophages, titania and ceria had no significant effect on viability in the whole range of nominal doses tested (15-240 μg/cm2 of monolayer), while CuO NPs produced a marked viability loss. Moreover, only CuO NPs, but not the other NPs, lowered TEER of Calu-3 monolayers, pointing to the impairment of the epithelial barrier. TEER decreased by 30 % at the dose of 10 μg/cm2 of CuO NPs, compared to untreated control, and was abolished at doses ≥80 μg/cm2, in strict correlation with changes in cell viability. These results indicate that (1) CuO NPs increase airway epithelium permeability even at relatively low doses and are significantly toxic for macrophages and airway epithelial cells, likely through the release of Cu ions in the medium; (2) TiO2 and CeO2 NPs do not affect TEER and exhibit little acute toxicity for airway epithelial cells and macrophages; and (3) TEER measurement can provide a simple method to assess the impairment of in vitro airway epithelial barrier model by manufactured nanomaterials.

Modulation of Intestinal Epithelial Permeability in Differentiated Caco-2 Cells Exposed to Aflatoxin M1 and Ochratoxin A Individually or Collectively

Directory of Open Access Journals (Sweden)

Yanan Gao

2017-12-01

Full Text Available Aflatoxin M1 (AFM1 and ochratoxin A (OTA are mycotoxins commonly found in milk; however, their effects on intestinal epithelial cells have not been reported. In the present study, we show that AFM1 (0.12 and 12 μM and OTA (0.2 and 20 μM individually or collectively increased the paracellular flux of lucifer yellow and fluorescein isothiocyanate (FITC-dextrans (4 and 40 kDa and decreased transepithelial electrical resistance values in differentiated Caco-2 cells after 48 h of exposure, indicating increased epithelial permeability. Immunoblotting and immunofluorescent analysis revealed that AFM1, OTA, and their combination decreased the expression levels of tight junction (TJ proteins and disrupted their structures, namely, claudin-3, claudin-4, occludin, and zonula occludens-1 (ZO-1, and p44/42 mitogen-activated protein kinase (MAPK partially involved in the mycotoxins-induced disruption of intestinal barrier. The effects of a combination of AFM1 and OTA on intestinal barrier function were more significant (p < 0.05 than those of AFM1 and OTA alone, yielding additive or synergistic effects. The additive or synergistic effects of AFM1 and OTA on intestinal barrier function might affect human health, especially in children, and toxin risks should be considered.

Permeability of the blood-brain barrier predicts conversion from optic neuritis to multiple sclerosis

DEFF Research Database (Denmark)

Cramer, Stig P; Modvig, Signe; Simonsen, Helle Juhl

2015-01-01

in the permeability of the blood-brain barrier in normal-appearing white matter of patients with multiple sclerosis and here, for the first time, we present a study on the capability of blood-brain barrier permeability in predicting conversion from optic neuritis to multiple sclerosis and a direct comparison...... with cerebrospinal fluid markers of inflammation, cellular trafficking and blood-brain barrier breakdown. To this end, we applied dynamic contrast-enhanced magnetic resonance imaging at 3 T to measure blood-brain barrier permeability in 39 patients with monosymptomatic optic neuritis, all referred for imaging...... fluid as well as levels of CXCL10 and MMP9 in the cerebrospinal fluid. These findings suggest that blood-brain barrier permeability, as measured by magnetic resonance imaging, may provide novel pathological information as a marker of neuroinflammation related to multiple sclerosis, to some extent...

Neutrophils Compromise Retinal Pigment Epithelial Barrier Integrity

Directory of Open Access Journals (Sweden)

Jiehao Zhou

2010-01-01

Full Text Available We hypothesized that neutrophils and their secreted factors mediate breakdown of the integrity of the outer blood-retina-barrier by degrading the apical tight junctions of the retinal pigment epithelium (RPE. The effect of activated neutrophils or neutrophil cell lysate on apparent permeability of bovine RPE-Choroid explants was evaluated by measuring [H] mannitol flux in a modified Ussing chamber. The expression of matrix metalloproteinase- (MMP- 9 in murine peritoneal neutrophils, and the effects of neutrophils on RPE tight-junction protein expression were assessed by confocal microscopy and western blot. Our results revealed that basolateral incubation of explants with neutrophils decreased occludin and ZO-1 expression at 1 and 3 hours and increased the permeability of bovine RPE-Choroid explants by >3-fold (P<.05. Similarly, basolateral incubation of explants with neutrophil lysate decreased ZO-1 expression at 1 and 3 hours (P<.05 and increased permeability of explants by 75%. Further, we found that neutrophils prominently express MMP-9 and that incubation of explants with neutrophils in the presence of anti-MMP-9 antibody inhibited the increase in permeability. These data suggest that neutrophil-derived MMP-9 may play an important role in disrupting the integrity of the outer blood-retina barrier.

SURFACE-ALTERED ZEOLITES AS PERMEABLE BARRIERS FOR IN SITU TREATMENT OF CONTAMINATED GROUNDWATER

International Nuclear Information System (INIS)

Bowman, Robert S.; Li, Zhaohui; Roy, Stephen J.; Burt, Todd; Johnson, Timothy L.; Johnson, Richard L.

1999-01-01

The overall objective of this effort is to develop and test a zeolite-based permeable barrier system for containing and remediating contaminated groundwater. The projected product is an engineered and tested permeable barrier system that can be adopted by the commercial sector

SURFACE-ALTERED ZEOLITES AS PERMEABLE BARRIERS FOR IN SITU TREATMENT OF CONTAMINATED GROUNDWATER

Energy Technology Data Exchange (ETDEWEB)

Robert S. Bowman; Zhaohui Li; Stephen J. Roy; Todd Burt; Timothy L. Johnson; Richard L. Johnson

1999-08-30

The overall objective of this effort is to develop and test a zeolite-based permeable barrier system for containing and remediating contaminated groundwater. The projected product is an engineered and tested permeable barrier system that can be adopted by the commercial sector.

Permeability of skin and oral mucosa to water and horseradish peroxidase as related to the thickness of the permeability barrier

International Nuclear Information System (INIS)

Squier, C.A.; Hall, B.K.

1985-01-01

The permeability of porcine skin and keratinized and nonkeratinized oral mucosa to tritium-labeled water and horseradish peroxidase (HRPO) was determined using perfusion chambers. Small blocks from each tissue were also incubated with HRPO and the extent of penetration visualized microscopically; this enabled measurements to be made of the thickness of the permeability barrier to this water-soluble tracer. Results obtained after inverting the oral mucosa in the chambers or adding metabolic inhibitors indicated that both compounds diffuse across the tissue. The permeability constants derived directly in the study showed that skin was less permeable than oral mucosa and that the floor of the mouth was significantly more permeable than all other regions. When these constants were normalized in terms of a standard permeability barrier thickness and the different tissues compared, the values obtained for skin were again less than those of the oral regions but, of these, the buccal mucosa was significantly higher. The difference in permeability between epidermis and keratinized oral epithelium may be due to differences in the volume density of membrane-coating granules known to exist between the tissues; differences between the oral mucosal regions may reflect differences in the nature of the intercellular barrier material

Imbalance of gut microbiome and intestinal epithelial barrier dysfunction in patients with high blood pressure.

Science.gov (United States)

Kim, Seungbum; Goel, Ruby; Kumar, Ashok; Qi, Yanfei; Lobaton, Gil; Hosaka, Koji; Mohammed, Mohammed; Handberg, Eileen M; Richards, Elaine M; Pepine, Carl J; Raizada, Mohan K

2018-03-30

Recent evidence indicates a link between gut pathology and microbiome with hypertension (HTN) in animal models. However, whether this association exists in humans is unknown. Thus, our objectives in the present study were to test the hypotheses that high blood pressure (BP) patients have distinct gut microbiomes and that gut-epithelial barrier function markers and microbiome composition could predict systolic BP (SBP). Fecal samples, analyzed by shotgun metagenomics, displayed taxonomic and functional changes, including altered butyrate production between patients with high BP and reference subjects. Significant increases in plasma of intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), and augmented gut-targetting proinflammatory T helper 17 (Th17) cells in high BP patients demonstrated increased intestinal inflammation and permeability. Zonulin, a gut epithelial tight junction protein regulator, was markedly elevated, further supporting gut barrier dysfunction in high BP. Zonulin strongly correlated with SBP (R 2 = 0.5301, P <0.0001). Two models predicting SBP were built using stepwise linear regression analysis of microbiome data and circulating markers of gut health, and validated in a separate cohort by prediction of SBP from zonulin in plasma (R 2 = 0.4608, P <0.0001). The mouse model of HTN, chronic angiotensin II (Ang II) infusion, was used to confirm the effects of butyrate and gut barrier function on the cardiovascular system and BP. These results support our conclusion that intestinal barrier dysfunction and microbiome function are linked to HTN in humans. They suggest that manipulation of gut microbiome and its barrier functions could be the new therapeutic and diagnostic avenues for HTN. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Permeable bio-reactive barriers for hydrocarbon remediation in Antarctica

Energy Technology Data Exchange (ETDEWEB)

Mumford, K.A.; Stevens, G.W.; Gore, D.B. [Melbourne Univ., Victoria (Australia). Dept. of Chemical and Biomoleculuar Engineering, Particulate Fluids Processing Centre; Snape, I.; Rayner, J.L. [Australian Antarctic Div., Kingston, Tasmania (Australia); Gore, D.B. [Macquarie Univ., Sydney, NSW (Australia). Dept. of Environmental Science

2010-07-01

This study assessed the performance of a permeable bio-reactive barrier designed to treat contaminated water. The bio-reactive barrier was installed at a fuel spill site located in the Windmill Islands, Antarctica. A funnel and gate design was used to prevent contaminant migration beyond the barrier location as well as to ensure controlled nutrient delivery. The study also investigated the performance of the bio-reactive barrier in regions with freeze-thaw conditions. The 4-year project was also conducted to assess optimal conditions for enhancing the barrier's ability to degrade hydrocarbons.

Live Faecalibacterium prausnitzii in an apical anaerobic model of the intestinal epithelial barrier.

Science.gov (United States)

Ulluwishewa, Dulantha; Anderson, Rachel C; Young, Wayne; McNabb, Warren C; van Baarlen, Peter; Moughan, Paul J; Wells, Jerry M; Roy, Nicole C

2015-02-01

Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate anaerobe, difficult to co-culture in viable form with oxygen-requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co-culture of live obligate anaerobes with the human intestinal cell line Caco-2, was developed. Caco-2 cells remained viable and maintained an intact barrier for at least 12 h, consistent with gene expression data, which suggested Caco-2 cells had adapted to survive in an oxygen-reduced atmosphere. Live F. prausnitzii cells, but not ultraviolet (UV)-killed F. prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco-2 cells exposed to live F. prausnitzii than UV-killed F. prausnitzii, This, consistent with previous reports, implies that live F. prausnitzii produces an anti-inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co-culture system that allows obligate anaerobic bacteria to remain viable. © 2014 John Wiley & Sons Ltd.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium.

Science.gov (United States)

Smith, I M; Baker, A; Arneborg, N; Jespersen, L

2015-11-01

The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast

The pH-sensing receptor OGR1 improves barrier function of epithelial cells and inhibits migration in an acidic environment.

Science.gov (United States)

de Vallière, Cheryl; Vidal, Solange; Clay, Ieuan; Jurisic, Giorgia; Tcymbarevich, Irina; Lang, Silvia; Ludwig, Marie-Gabrielle; Okoniewski, Michal; Eloranta, Jyrki J; Kullak-Ublick, Gerd A; Wagner, Carsten A; Rogler, Gerhard; Seuwen, Klaus

2015-09-15

The pH-sensing receptor ovarian cancer G protein-coupled receptor 1 (OGR1; GPR68) is expressed in the gut. Inflammatory bowel disease is typically associated with a decrease in local pH, which may lead to altered epithelial barrier function and subsequent gastrointestinal repair involving epithelial cell adhesion and migration. As the mechanisms underlying the response to pH changes are not well understood, we have investigated OGR1-mediated, pH-dependent signaling pathways in intestinal epithelial cells. Caco-2 cells stably overexpressing OGR1 were created and validated as tools to study OGR1 signaling. Barrier function, migration, and proliferation were measured using electric cell-substrate impedance-sensing technology. Localization of the tight junction proteins zonula occludens protein 1 and occludin and the rearrangement of cytoskeletal actin were examined by confocal microscopy. Paracellular permeability and protein and gene expression analysis using DNA microarrays were performed on filter-grown Caco-2 monolayers. We report that an acidic pH shift from pH 7.8 to 6.6 improved barrier function and stimulated reorganization of filamentous actin with prominent basal stress fiber formation. Cell migration and proliferation during in vitro wound healing were inhibited. Gene expression analysis revealed significant upregulation of genes related to cytoskeleton remodeling, cell adhesion, and growth factor signaling. We conclude that acidic extracellular pH can have a signaling function and impact the physiology of intestinal epithelial cells. The deconstruction of OGR1-dependent signaling may aid our understanding of mucosal inflammation mechanisms. Copyright © 2015 the American Physiological Society.

Evaluation of synthetic zeolite as engineering passive permeable reactive barrier

International Nuclear Information System (INIS)

Ibrahim, O.A.A.

2011-01-01

The presence of toxic pollutants in groundwater brings about significant changes in the properties of water resources and has to be avoided in order to preserve the environmental quality. Heavy metals are among the most dangerous inorganic water pollutants, that related to many anthropogenic sources and their compounds are extremely toxic. The treatment of contaminated groundwater is among the most difficult and expensive environmental problems. Over the past years, permeable reactive barriers have provided an increasingly important role in the passive insitu treatment of contaminated groundwater. There are a large number of materials that are able to immobilize contaminants by sorption, including granulated active carbon, zeolite, montmorillonite, peat, compost, sawdust, etc. Zeolite X is a synthetic counterpart of the naturally occurring mineral Faujasite. It has one of the largest cavities and cavity entrances of any known zeolites. The main aim of this work is to examine the possibility of using synthetic zeolite X as an engineering permeable reactive barrier to remove heavy metals from a contaminated groundwater. Within this context, the following investigations were carried out: 1. Review on the materials most commonly used as engineered permeable reactive barriers to identify the important features to be considered in the examination of the proposed permeable reactive barrier material (zeolite X). 2. Synthesis of zeolite X and characterization of the synthesized material using different techniques. 3. Batch tests were carried out to characterize the equilibrium and kinetic sorption properties of the synthesized zeolite X towards the concerned heavy metals; zinc and cadmium ions. 4. Column tests were also performed to determine the design factors for permeable reactive barrier against zinc and cadmium ions solutions.Breakthrough curves measured in such experiments used to determine the hydrodynamic dispersion coefficients for both metal ions. 5. Analytical

Test device for measuring permeability of a barrier material

Science.gov (United States)

Reese, Matthew; Dameron, Arrelaine; Kempe, Michael

2014-03-04

A test device for measuring permeability of a barrier material. An exemplary device comprises a test card having a thin-film conductor-pattern formed thereon and an edge seal which seals the test card to the barrier material. Another exemplary embodiment is an electrical calcium test device comprising: a test card an impermeable spacer, an edge seal which seals the test card to the spacer and an edge seal which seals the spacer to the barrier material.

Alveolar epithelial permeability in bronchial asthma in children

International Nuclear Information System (INIS)

Oishi, Takuji

1993-01-01

To evaluate alveolar epithelial permeability (k ep ) in children with bronchial asthma, 99m Tc-DTPA (diethylene triamine penta acetate) aerosol lung inhalation scintigraphies were performed. There was no correlation between the k ep value and the severity of asthma. On the other hand, out of 10 cases which had no aerosol deposition defect in the lung field, 4 showed high k ep values on the whole lung field and 7 had high k ep value areas, particularly apparent in the upper lung field. These results suggest that even when the central airway lesions are mild, severe damage exists in the alveolar region of the peripheral airway. (author)

Lifelong consumption of sodium selenite: gender differences on blood-brain barrier permeability in convulsive, hypoglycemic rats.

Science.gov (United States)

Seker, F Burcu; Akgul, Sibel; Oztas, Baria

2008-07-01

The aim of this study was to compare the effects of hypoglycemia and induced convulsions on the blood-brain barrier permeability in rats with or without lifelong administration of sodium selenite. There is a significant decrease of the blood-brain barrier permeability in three brain regions of convulsive, hypoglycemic male rats treated with sodium selenite when compared to sex-matched untreated rats (p0.05). The blood-brain barrier permeability of the left and right hemispheres of untreated, moderately hypoglycemic convulsive rats of both genders was better than their untreated counterparts (peffect against blood-brain barrier permeability during convulsions and that the effects of sodium selenite are gender-dependent.

Mucosal pathobiology and molecular signature of epithelial barrier dysfunction in the small intestine in irritable bowel syndrome.

Science.gov (United States)

González-Castro, Ana M; Martínez, Cristina; Salvo-Romero, Eloísa; Fortea, Marina; Pardo-Camacho, Cristina; Pérez-Berezo, Teresa; Alonso-Cotoner, Carmen; Santos, Javier; Vicario, María

2017-01-01

Irritable bowel syndrome (IBS) is one of the most prevalent gastrointestinal disorders in developed countries. Its etiology remains unknown; however, a common finding, regardless of IBS subtype, is the presence of altered intestinal barrier. In fact, signaling and location of cell-to-cell adhesion proteins, in connection with increased immune activity, seem abnormal in the intestinal epithelium of IBS patients. Despite that most research is performed on distal segments of the intestine, altered permeability has been reported in both, the small and the large bowel of all IBS subtypes. The small intestine carries out digestion and nutrient absorption and is also the site where the majority of immune responses to luminal antigens takes place. In fact, the upper intestine is more exposed to environmental antigens than the colon and is also a site of symptom generation. Recent studies have revealed small intestinal structural alterations of the epithelial barrier and mucosal immune activation in association with intestinal dysfunction, suggesting the commitment of the intestine as a whole in the pathogenesis of IBS. This review summarizes the most recent findings on mucosal barrier alterations and its relationship to symptoms arising from the small intestine in IBS, including epithelial structural abnormalities, mucosal immune activation, and microbial dysbiosis, further supporting the hypothesis of an organic origin of IBS. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

The biofiltration permeable reactive barrier: Practical experience from Synthesia

Energy Technology Data Exchange (ETDEWEB)

Vesela, L.; Nemecek, J.; Siglova, M.; Kubal, M. [DEKONTA, Prague (Czech Republic)

2006-10-15

The paper refers to utilization of biological elements within permeable reactive barriers. The concept of a biofiltration permeable barrier has been tested in the laboratory and in pilot-scale. Oxyhumolite (oxidized young lignite) was examined as an absorption material and a biofilm carrier. Laboratory tests performed before the pilot verification confirmed that oxyhumolite adsorbs organic pollutants at a minimum value, but that it can be used for biofilm attachment. An experimental barrier was built on premises of a chemical factory contaminated mainly by various organic pollutants (benzene, toluene, ethylbenzene, and xylenes (BTEX), chlorobenzenes, naphthalene, nitro-derivatives, phenols, trichloroethylene (TCE), and total petroleum hydrocarbon (TPH)). Before the barrier was installed, a preliminary survey of the unsaturated zone, hydrogeological investigation, and a microbiological survey had been performed. The barrier was designed as a trench-and-gate system with an in situ bioreactor. During the year 2004, measurements of groundwater flux and retention time under current hydrological conditions, together with chemical and microbiological monitoring, were carried out on the site. The results showed high effectiveness of organic contamination removal. Average elimination varied from 57.3% (naphthalene) to 99.9% (nitro-derivatives, BTEX); microbial density in the bioreactor was approx. 10{sup 5} CFU mL{sup -1}.

Haemophilia, AIDS and lung epithelial permeability

Energy Technology Data Exchange (ETDEWEB)

O' Doherty, M.J.; Page, C.J.; Harrington, C.; Nunan, T.; Savidge, G. (Haemophilia Centre and Coagulation Research Unit, Department of Nuclear Medicine, Rayne Institute, St. Thomas' Hospital, London (United Kingdom))

1990-01-01

Lung {sup 99m}Tc DTPA transfer was measured in HIV antibodypositive haemophiliacs (11 smokers, 26 nonsmokers, 5 patients with Pneumocystis carinii pneumonia (PCP)). Lung {sup 99m}Tc DTPA transfer as a marker of lung epithelial permeability was measured as the half time of transfer (from airspace into blood). This half time was faster in smokers compred to nonsmokers and the transfer curve was monoexponential. In nonsmokers no difference was observed between asymptomatic HIV-positive haemophiliacs and normal subjects, with the exception of the lung bases. At the lung basis in HIV-positive haemophiliac nonsmokers the transfer was faster than in normal individuals, implying increased alveolar permeability. Pneumocystis carinii pneumonia resulted in a rapid transfer of {sup 99m}Tc DTPA (mean T50 of 2 minutes) and the transfer curve was biphasic, confirming previous observations in homosexual HIV antibody-positive patients with PCP. These changes returned to a monoexponential profile by 6 weeks following successful treatment. The DTPA lung transfer study may enable clinicians to instigate therapy for PCP without the need for initial bronchoscopy and provide a noninvasive method for the reassessment of patients should further respiratory signs or symptoms develop. This method is considered to be highly cost-effective in that it obviates the use of factor VIII concentrates required to cover bronchoscopic procedures and, with its early application and ease of use as a follow-up investigation, permits the evaluation of patients on an outpatient basis, thus reducing hospital costs. (au).

Haemophilia, AIDS and lung epithelial permeability

International Nuclear Information System (INIS)

O'Doherty, M.J.; Page, C.J.; Harrington, C.; Nunan, T.; Savidge, G.

1990-01-01

Lung 99m Tc DTPA transfer was measured in HIV antibodypositive haemophiliacs (11 smokers, 26 nonsmokers, 5 patients with Pneumocystis carinii pneumonia (PCP)). Lung 99m Tc DTPA transfer as a marker of lung epithelial permeability was measured as the half time of transfer (from airspace into blood). This half time was faster in smokers compred to nonsmokers and the transfer curve was monoexponential. In nonsmokers no difference was observed between asymptomatic HIV-positive haemophiliacs and normal subjects, with the exception of the lung bases. At the lung basis in HIV-positive haemophiliac nonsmokers the transfer was faster than in normal individuals, implying increased alveolar permeability. Pneumocystis carinii pneumonia resulted in a rapid transfer of 99m Tc DTPA (mean T50 of 2 minutes) and the transfer curve was biphasic, confirming previous observations in homosexual HIV antibody-positive patients with PCP. These changes returned to a monoexponential profile by 6 weeks following successful treatment. The DTPA lung transfer study may enable clinicians to instigate therapy for PCP without the need for initial bronchoscopy and provide a noninvasive method for the reassessment of patients should further respiratory signs or symptoms develop. This method is considered to be highly cost-effective in that it obviates the use of factor VIII concentrates required to cover bronchoscopic procedures and, with its early application and ease of use as a follow-up investigation, permits the evaluation of patients on an outpatient basis, thus reducing hospital costs. (au)

Glycogen Synthase Kinase 3 (GSK-3) influences epithelial barrier function by regulating Occludin, Claudin-1 and E-cadherin expression

International Nuclear Information System (INIS)

Severson, Eric A.; Kwon, Mike; Hilgarth, Roland S.; Parkos, Charles A.; Nusrat, Asma

2010-01-01

The Apical Junctional Complex (AJC) encompassing the tight junction (TJ) and adherens junction (AJ) plays a pivotal role in regulating epithelial barrier function and epithelial cell proliferative processes through signaling events that remain poorly characterized. A potential regulator of AJC protein expression is Glycogen Synthase Kinase-3 (GSK-3). GSK-3 is a constitutively active kinase that is repressed during epithelial-mesenchymal transition (EMT). In the present study, we report that GSK-3 activity regulates the structure and function of the AJC in polarized model intestinal (SK-CO15) and kidney (Madin-Darby Canine Kidney (MDCK)) epithelial cells. Reduction of GSK-3 activity, either by small molecule inhibitors or siRNA targeting GSK-3 alpha and beta mRNA, resulted in increased permeability to both ions and bulk solutes. Immunofluorescence labeling and immunoblot analyses revealed that the barrier defects correlated with decreased protein expression of AJC transmembrane proteins Occludin, Claudin-1 and E-cadherin without influencing other TJ proteins, Zonula Occludens-1 (ZO-1) and Junctional Adhesion Molecule A (JAM-A). The decrease in Occludin and E-cadherin protein expression correlated with downregulation of the corresponding mRNA levels for these respective proteins following GSK-3 inhibition. These observations implicate an important role of GSK-3 in the regulation of the structure and function of the AJC that is mediated by differential modulation of mRNA transcription of key AJC proteins, Occludin, Claudin-1 and E-cadherin.

Glycogen Synthase Kinase 3 (GSK-3) influences epithelial barrier function by regulating Occludin, Claudin-1 and E-cadherin expression

Energy Technology Data Exchange (ETDEWEB)

Severson, Eric A.; Kwon, Mike; Hilgarth, Roland S.; Parkos, Charles A. [Epithelial Pathobiology Research Unit, Dept. of Pathology, Emory University, Atlanta, GA 30322 (United States); Nusrat, Asma, E-mail: anusrat@emory.edu [Epithelial Pathobiology Research Unit, Dept. of Pathology, Emory University, Atlanta, GA 30322 (United States)

2010-07-02

The Apical Junctional Complex (AJC) encompassing the tight junction (TJ) and adherens junction (AJ) plays a pivotal role in regulating epithelial barrier function and epithelial cell proliferative processes through signaling events that remain poorly characterized. A potential regulator of AJC protein expression is Glycogen Synthase Kinase-3 (GSK-3). GSK-3 is a constitutively active kinase that is repressed during epithelial-mesenchymal transition (EMT). In the present study, we report that GSK-3 activity regulates the structure and function of the AJC in polarized model intestinal (SK-CO15) and kidney (Madin-Darby Canine Kidney (MDCK)) epithelial cells. Reduction of GSK-3 activity, either by small molecule inhibitors or siRNA targeting GSK-3 alpha and beta mRNA, resulted in increased permeability to both ions and bulk solutes. Immunofluorescence labeling and immunoblot analyses revealed that the barrier defects correlated with decreased protein expression of AJC transmembrane proteins Occludin, Claudin-1 and E-cadherin without influencing other TJ proteins, Zonula Occludens-1 (ZO-1) and Junctional Adhesion Molecule A (JAM-A). The decrease in Occludin and E-cadherin protein expression correlated with downregulation of the corresponding mRNA levels for these respective proteins following GSK-3 inhibition. These observations implicate an important role of GSK-3 in the regulation of the structure and function of the AJC that is mediated by differential modulation of mRNA transcription of key AJC proteins, Occludin, Claudin-1 and E-cadherin.

Scaffolding proteins in the development and maintenance of the epidermal permeability barrier.

Science.gov (United States)

Crawford, Melissa; Dagnino, Lina

2017-10-02

The skin of mammals and other terrestrial vertebrates protects the organism against the external environment, preventing heat, water and electrolyte loss, as well as entry of chemicals and pathogens. Impairments in the epidermal permeability barrier function are associated with the genesis and/or progression of a variety of pathological conditions, including genetic inflammatory diseases, microbial and viral infections, and photodamage induced by UV radiation. In mammals, the outside-in epidermal permeability barrier is provided by the joint action of the outermost cornified layer, together with assembled tight junctions in granular keratinocytes found in the layers underneath. Tight junctions serve as both outside-in and inside-out barriers, and impede paracellular movements of ions, water, macromolecules and microorganisms. At the molecular level, tight junctions consist of integral membrane proteins that form an extracellular seal between adjacent cells, and associate with cytoplasmic scaffold proteins that serve as links with the actin cytoskeleton. In this review, we address the roles that scaffold proteins play specifically in the establishment and maintenance of the epidermal permeability barrier, and how various pathologies alter or impair their functions.

Severe Burn-Induced Intestinal Epithelial Barrier Dysfunction Is Associated With Endoplasmic Reticulum Stress and Autophagy in Mice

Science.gov (United States)

Huang, Yalan; Feng, Yanhai; Wang, Yu; Wang, Pei; Wang, Fengjun; Ren, Hui

2018-01-01

The disruption of intestinal barrier plays a vital role in the pathophysiological changes after severe burn injury, however, the underlying mechanisms are poorly understood. Severe burn causes the disruption of intestinal tight junction (TJ) barrier. Previous studies have shown that endoplasmic reticulum (ER) stress and autophagy are closely associated with the impairment of intestinal mucosa. Thus, we hypothesize that ER stress and autophagy are likely involved in burn injury-induced intestinal epithelial barrier dysfunction. Mice received a 30% total body surface area (TBSA) full-thickness burn, and were sacrificed at 0, 1, 2, 6, 12 and 24 h postburn. The results showed that intestinal permeability was increased significantly after burn injury, accompanied by the damage of mucosa and the alteration of TJ proteins. Severe burn induced ER stress, as indicated by increased intraluminal chaperone binding protein (BIP), CCAAT/enhancer-binding protein homologous protein (CHOP) and inositol-requiring enzyme 1(IRE1)/X-box binding protein 1 splicing (XBP1). Autophagy was activated after burn injury, as evidenced by the increase of autophagy related protein 5 (ATG5), Beclin 1 and LC3II/LC3I ratio and the decrease of p62. Besides, the number of autophagosomes was also increased after burn injury. The levels of p-PI3K(Ser191), p-PI3K(Ser262), p-AKT(Ser473), and p-mTOR were decreased postburn, suggesting that autophagy-related PI3K/AKT/mTOR pathway is involved in the intestinal epithelial barrier dysfunction following severe burn. In summary, severe burn injury induces the ER stress and autophagy in intestinal epithelia, leading to the disruption of intestinal barrier. PMID:29740349

Contacting co-culture of human retinal microvascular endothelial cells alters barrier function of human embryonic stem cell derived retinal pigment epithelial cells.

Science.gov (United States)

Skottman, H; Muranen, J; Lähdekorpi, H; Pajula, E; Mäkelä, K; Koivusalo, L; Koistinen, A; Uusitalo, H; Kaarniranta, K; Juuti-Uusitalo, K

2017-10-01

Here we evaluated the effects of human retinal microvascular endothelial cells (hREC) on mature human embryonic stem cell (hESC) derived retinal pigment epithelial (RPE) cells. The hESC-RPE cells (Regea08/017, Regea08/023 or Regea11/013) and hREC (ACBRI 181) were co-cultured on opposite sides of transparent membranes for up to six weeks. Thereafter barrier function, small molecule permeability, localization of RPE and endothelial cell marker proteins, cellular fine structure, and growth factor secretion of were evaluated. After co-culture, the RPE specific CRALBP and endothelial cell specific von Willebrand factor were appropriately localized. In addition, the general morphology, pigmentation, and fine structure of hESC-RPE cells were unaffected. Co-culture increased the barrier function of hESC-RPE cells, detected both with TEER measurements and cumulative permeability of FD4 - although the differences varied among the cell lines. Co-culturing significantly altered VEGF and PEDF secretion, but again the differences were cell line specific. The results of this study showed that co-culture with hREC affects hESC-RPE functionality. In addition, co-culture revealed drastic cell line specific differences, most notably in growth factor secretion. This model has the potential to be used as an in vitro outer blood-retinal barrier model for drug permeability testing. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Control of BTEX migration using a biologically enhanced permeable barrier

International Nuclear Information System (INIS)

Borden, R.C.; Goin, R.T.; Kao, C.M.

1997-01-01

A permeable barrier system, consisting of a line of closely spaced wells, was installed perpendicular to ground water flow to control the migration of a dissolved hydrocarbon plume. The wells were charged with concrete briquets that release oxygen and nitrate at a controlled rate, enhancing aerobic biodegradation in the downgradient aquifer. Laboratory batch reactor experiments were conducted to identify concrete mixtures that slowly released oxygen over an extended time period. A full-scale permeable barrier system using ORC was constructed at a gasoline-spill site. During the first 242 days of operation, total BTEX decreased from 17 to 3.4 mg/L and dissolved oxygen increased from 0.4 to 1.8 mg/L during transport through the barrier. Over time, BTEX treatment efficiencies declined, indicating the barrier system had become less effective in releasing oxygen and nutrients to the highly contaminated portion of the aquifer. Point dilution tests and sediment analyses performed at the conclusion of the project indicated that the aquifer in the vicinity of the remediation wells had been clogged by precipitation with iron minerals

Host Epithelial Interactions with Helicobacter Pylori: A Role for Disrupted Gastric Barrier Function in the Clinical Outcome of Infection?

Directory of Open Access Journals (Sweden)

Andre G Buret

2005-01-01

Full Text Available Infection of the human stomach with Helicobacter pylori may develop into gastritis, ulceration, adenocarcinoma and mucosal lymphomas. The pathogenic mechanisms that determine the clinical outcome from this microbial-epithelial interaction remain poorly understood. An increasing number of reports suggests that disruptions of epithelial barrier function may contribute to pathology and postinfectious complications in a variety of gastrointestinal infections. The aim of this review is to critically discuss the implications of H pylori persistence on gastric disease, with emphasis on the role of myosin light chain kinase, claudins and matrix metalloproteinases in gastric permeability defects, and their contribution to the development of cancer. These mechanisms and the associated signalling events may represent novel therapeutic targets to control disease processes induced by H pylori, a microbial pathogen that colonizes the stomach of over 50% of the human population.

ECONOMICS ANALYSIS OF THE IMPLEMENTATION OF PERMEABLE REACTIVE BARRIERS FOR REMEDIATION OF CONTAMINATED GROUND WATER

Science.gov (United States)

This report presents an analysis of the cost of using permeable reactive barriers to remediate contaminated ground water. When possible, these costs are compared with the cost of pump-and-treat technology for similar situations. Permeable reactive barriers are no longer perceiv...

Deoxynivalenol affects in vitro intestinal epithelial cell barrier integrity through inhibition of protein synthesis

International Nuclear Information System (INIS)

Van De Walle, Jacqueline; Sergent, Therese; Piront, Neil; Toussaint, Olivier; Schneider, Yves-Jacques; Larondelle, Yvan

2010-01-01

Deoxynivalenol (DON), one of the most common mycotoxin contaminants of raw and processed cereal food, adversely affects the gastrointestinal tract. Since DON acts as a protein synthesis inhibitor, the constantly renewing intestinal epithelium could be particularly sensitive to DON. We analyzed the toxicological effects of DON on intestinal epithelial protein synthesis and barrier integrity. Differentiated Caco-2 cells, as a widely used model of the human intestinal barrier, were exposed to realistic intestinal concentrations of DON (50, 500 and 5000 ng/ml) during 24 h. DON caused a concentration-dependent decrease in total protein content associated with a reduction in the incorporation of [ 3 H]-leucine, demonstrating its inhibitory effect on protein synthesis. DON simultaneously increased the paracellular permeability of the monolayer as reflected through a decreased transepithelial electrical resistance associated with an increased paracellular flux of the tracer [ 3 H]-mannitol. A concentration-dependent reduction in the expression level of the tight junction constituent claudin-4 was demonstrated by Western blot, which was not due to diminished transcription, increased degradation, or NF-κB, ERK or JNK activation, and was also observed for a tight junction independent protein, i.e. intestinal alkaline phosphatase. These results demonstrate a dual toxicological effect of DON on differentiated Caco-2 cells consisting in an inhibition of protein synthesis as well as an increase in monolayer permeability, and moreover suggest a possible link between them through diminished synthesis of the tight junction constituent claudin-4.

Probiotics promote endocytic allergen degradation in gut epithelial cells

International Nuclear Information System (INIS)

Song, Chun-Hua; Liu, Zhi-Qiang; Huang, Shelly; Zheng, Peng-Yuan; Yang, Ping-Chang

2012-01-01

Highlights: ► Knockdown of A20 compromised the epithelial barrier function. ► The fusion of endosome/lysosome was disturbed in the A20-deficient HT-29 cells. ► Antigens transported across A20-deficient HT-29 monolayers conserved antigenicity. ► Probiotic proteins increased the expression of A20 in HT-29 cells. -- Abstract: Background and aims: Epithelial barrier dysfunction plays a critical role in the pathogenesis of allergic diseases; the mechanism is to be further understood. The ubiquitin E3 ligase A20 (A20) plays a role in the endocytic protein degradation in the cells. This study aims to elucidate the role of A20 in the maintenance of gut epithelial barrier function. Methods: Gut epithelial cell line, HT-29 cell, was cultured into monolayers to evaluate the barrier function in transwells. RNA interference was employed to knock down the A20 gene in HT-29 cells to test the role of A20 in the maintenance of epithelial barrier function. Probiotic derived proteins were extracted from the culture supernatants using to enhance the expression of A20 in HT-29 cells. Results: The results showed that the knockdown of A20 compromised the epithelial barrier function in HT-29 monolayers, mainly increased the intracellular permeability. The fusion of endosome/lysosome was disturbed in the A20-deficient HT-29 cells. Allergens collected from the transwell basal chambers of A20-deficient HT-29 monolayers still conserved functional antigenicity. Treating with probiotic derived proteins increased the expression of A20 in HT-29 cells and promote the barrier function. Conclusion: A20 plays an important role in the maintenance of epithelial barrier function as shown by HT-29 monolayer. Probiotic derived protein increases the expression of A20 and promote the HT-29 monolayer barrier function.

Probiotics promote endocytic allergen degradation in gut epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Song, Chun-Hua [Department of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou (China); Liu, Zhi-Qiang [Department of Gastroenterology, The Second Hospital, Zhengzhou University, Zhengzhou (China); Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON (Canada); Huang, Shelly [Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON (Canada); Zheng, Peng-Yuan, E-mail: medp7123@126.com [Department of Gastroenterology, The Second Hospital, Zhengzhou University, Zhengzhou (China); Yang, Ping-Chang, E-mail: yangp@mcmaster.ca [Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON (Canada)

2012-09-14

Highlights: Black-Right-Pointing-Pointer Knockdown of A20 compromised the epithelial barrier function. Black-Right-Pointing-Pointer The fusion of endosome/lysosome was disturbed in the A20-deficient HT-29 cells. Black-Right-Pointing-Pointer Antigens transported across A20-deficient HT-29 monolayers conserved antigenicity. Black-Right-Pointing-Pointer Probiotic proteins increased the expression of A20 in HT-29 cells. -- Abstract: Background and aims: Epithelial barrier dysfunction plays a critical role in the pathogenesis of allergic diseases; the mechanism is to be further understood. The ubiquitin E3 ligase A20 (A20) plays a role in the endocytic protein degradation in the cells. This study aims to elucidate the role of A20 in the maintenance of gut epithelial barrier function. Methods: Gut epithelial cell line, HT-29 cell, was cultured into monolayers to evaluate the barrier function in transwells. RNA interference was employed to knock down the A20 gene in HT-29 cells to test the role of A20 in the maintenance of epithelial barrier function. Probiotic derived proteins were extracted from the culture supernatants using to enhance the expression of A20 in HT-29 cells. Results: The results showed that the knockdown of A20 compromised the epithelial barrier function in HT-29 monolayers, mainly increased the intracellular permeability. The fusion of endosome/lysosome was disturbed in the A20-deficient HT-29 cells. Allergens collected from the transwell basal chambers of A20-deficient HT-29 monolayers still conserved functional antigenicity. Treating with probiotic derived proteins increased the expression of A20 in HT-29 cells and promote the barrier function. Conclusion: A20 plays an important role in the maintenance of epithelial barrier function as shown by HT-29 monolayer. Probiotic derived protein increases the expression of A20 and promote the HT-29 monolayer barrier function.

Airway Epithelial Barrier Dysfunction in Chronic Obstructive Pulmonary Disease : Role of Cigarette Smoke Exposure

NARCIS (Netherlands)

Aghapour, Mahyar; Raee, Pourya; Moghaddam, Seyed Javad; Hiemstra, Pieter S.; Heijink, Irene H.

The epithelial lining of the airway forms the first barrier against environmental insults, such as inhaled cigarette smoke, which is the primary risk factor for the development of chronic obstructive pulmonary disease (COPD). The barrier is formed by airway epithelial junctions, which are

"Targeted disruption of the epithelial-barrier by Helicobacter pylori"

Directory of Open Access Journals (Sweden)

Wroblewski Lydia E

2011-11-01

Full Text Available Abstract Helicobacter pylori colonizes the human gastric epithelium and induces chronic gastritis, which can lead to gastric cancer. Through cell-cell contacts the gastric epithelium forms a barrier to protect underlying tissue from pathogenic bacteria; however, H. pylori have evolved numerous strategies to perturb the integrity of the gastric barrier. In this review, we summarize recent research into the mechanisms through which H. pylori disrupts intercellular junctions and disrupts the gastric epithelial barrier.

Perinatal supplementation of 4-phenylbutyrate and glutamine attenuates endoplasmic reticulum stress and improves colonic epithelial barrier function in rats born with intrauterine growth restriction.

Science.gov (United States)

Désir-Vigné, Axel; Haure-Mirande, Vianney; de Coppet, Pierre; Darmaun, Dominique; Le Dréan, Gwenola; Segain, Jean-Pierre

2018-05-01

Intrauterine growth restriction (IUGR) can affect the structure and function of the intestinal barrier and increase digestive disease risk in adulthood. Using the rat model of maternal dietary protein restriction (8% vs. 20%), we found that the colon of IUGR offspring displayed decreased mRNA expression of epithelial barrier proteins MUC2 and occludin during development. This was associated with increased mRNA expression of endoplasmic reticulum (ER) stress marker XBP1s and increased colonic permeability measured in Ussing chambers. We hypothesized that ER stress contributes to colonic barrier alterations and that perinatal supplementation of dams with ER stress modulators, phenylbutyrate and glutamine (PG) could prevent these defects in IUGR offspring. We first demonstrated that ER stress induction by tunicamycin or thapsigargin increased the permeability of rat colonic tissues mounted in Ussing chamber and that PG treatment prevented this effect. Therefore, we supplemented the diet of control and IUGR dams with PG during gestation and lactation. Real-time polymerase chain reaction and histological analysis of colons from 120-day-old offspring revealed that perinatal PG treatment partially prevented the increased expression of ER stress markers but reversed the reduction of crypt depth and goblet cell number in IUGR rats. In dextran sodium sulfate-induced injury and recovery experiments, the colon of IUGR rats without perinatal PG treatment showed higher XBP1s mRNA levels and histological scores of inflammation than IUGR rats with perinatal PG treatment. In conclusion, these data suggest that perinatal supplementation with PG could alleviate ER stress and prevent epithelial barrier dysfunction in IUGR offspring. Copyright © 2017 Elsevier Inc. All rights reserved.

Permeability measurement of some barrier materials as a function of temperature and pressure

International Nuclear Information System (INIS)

Maqsood, M.; Faisal, S.; Ali, J.; Usman, A.; Alamgir, K.; Farooq, K.

2011-01-01

Barrier materials possess the ability to restrict the passage of gases, vapors, and organic liquids through their boundaries. These barrier materials have large number of applications in industry and scientific research. To measure the permeability of barrier materials, a specific gas flow system has been developed, pure helium gas is used to measure the back ground reading through SS-316. The permeability and break-through time has been measured through Inconel X-750, NBR and Viton below and above the atmospheric pressure and at different temperatures 20 deg. C, 40 deg. C and 70 deg. C. (author)

HIV-1 impairs human retinal pigment epithelial barrier function: possible association with the pathogenesis of HIV-associated retinopathy.

Science.gov (United States)

Tan, Suiyi; Duan, Heng; Xun, Tianrong; Ci, Wei; Qiu, Jiayin; Yu, Fei; Zhao, Xuyan; Wu, Linxuan; Li, Lin; Lu, Lu; Jiang, Shibo; Liu, Shuwen

2014-07-01

The breakdown of human retinal pigment epithelial (HRPE) barrier is considered as the etiology of retinopathy, which affects the quality of life of HIV/AIDS patients. Here we demonstrate that HIV-1 could directly impair HRPE barrier function, which leads to the translocation of HIV-1 and bacteria. HRPE cells (D407) were grown to form polarized, confluent monolayers and treated with different HIV-1 infectious clones. A significant increase of monolayer permeability, as measured by trans-epithelial electrical resistance (TEER) and apical-basolateral movements of sodium fluorescein, was observed. Disrupted tightness of HRPE barrier was associated with the downregulation of several tight junction proteins in D407 cells, including ZO-1, Occludin, Claudin-1, Claudin-2, Claudin-3, Claudin-4, and Claudin-5, after exposure to HIV-1, without affecting the viability of cells. HIV-1 gp120 was shown to participate in the alteration of barrier properties, as evidenced by decreased TEER and weakened expression of tight junction proteins in D407 monolayers after exposure to pseudotyped HIV-1, UV-inactivated HIV-1, and free gp120, but not to an envelope (Env)-defective mutant of HIV. Furthermore, exposure to HIV-1 particles could induce the release of pro-inflammatory cytokines in D407, including IL-6 and MCP-1, both of which downregulated the expression of ZO-1 in the HRPE barrier. Disrupted HRPE monolayer allowed translocation of HIV-1 and bacteria across the epithelium. Overall, these findings suggest that HIV-1 may exploit its Env glycoprotein to induce an inflammatory state in HRPE cells, which could result in impairment of HRPE monolayer integrity, allowing virus and bacteria existing in ocular fluids to cross the epithelium and penetrate the HRPE barrier. Our study highlights the role of HIV-1 in the pathogenesis of HIV/AIDS-related retinopathy and suggests potential therapeutic targets for this ocular complication.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium

DEFF Research Database (Denmark)

Smith, Ida Mosbech; Baker, A; Arneborg, Nils

2015-01-01

distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase....... In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability......). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. SIGNIFICANCE AND IMPACT...

Oral and fecal Campylobacter concisus strains perturb barrier function by apoptosis induction in HT-29/B6 intestinal epithelial cells.

Directory of Open Access Journals (Sweden)

Hans Linde Nielsen

Full Text Available Campylobacter concisus infections of the gastrointestinal tract can be accompanied by diarrhea and inflammation, whereas colonization of the human oral cavity might have a commensal nature. We focus on the pathophysiology of C. concisus and the effects of different clinical oral and fecal C. concisus strains on human HT-29/B6 colon cells. Six oral and eight fecal strains of C. concisus were isolated. Mucus-producing HT-29/B6 epithelial monolayers were infected with the C. concisus strains. Transepithelial electrical resistance (R(t and tracer fluxes of different molecule size were measured in Ussing chambers. Tight junction (TJ protein expression was determined by Western blotting, and subcellular TJ distribution was analyzed by confocal laser-scanning microscopy. Apoptosis induction was examined by TUNEL-staining and Western blot of caspase-3 activation. All strains invaded confluent HT-29/B6 cells and impaired epithelial barrier function, characterized by a time- and dose-dependent decrease in R(t either after infection from the apical side but even more from the basolateral compartment. TJ protein expression changes were sparse, only in apoptotic areas of infected monolayers TJ proteins were redistributed. Solely the barrier-forming TJ protein claudin-5 showed a reduced expression level to 66±8% (P<0.05, by expression regulation from the gene. Concomitantly, Lactate dehydrogenase release was elevated to 3.1±0.3% versus 0.7±0.1% in control (P<0.001, suggesting cytotoxic effects. Furthermore, oral and fecal C. concisus strains elevated apoptotic events to 5-fold. C. concisus-infected monolayers revealed an increased permeability for 332 Da fluorescein (1.74±0.13 vs. 0.56±0.17 10(-6 cm/s in control, P<0.05 but showed no difference in permeability for 4 kDa FITC-dextran (FD-4. The same was true in camptothecin-exposed monolayers, where camptothecin was used for apoptosis induction.In conclusion, epithelial barrier dysfunction by oral and

Strength and Numerical Analysis in the Design of Permeable Reactive Barriers

Science.gov (United States)

Pawluk, Katarzyna; Wrzesiński, Grzegorz; Lendo-Siwicka, Marzena

2017-10-01

Permeable reactive barriers are one of the most important in situ technologies in groundwater remediation. Most of the installed PRBs have tended to use singular reactive media, but there is an increasing number of applications using combined or sequenced media to treat mixtures of contaminants within a groundwater plume. The concept of a multi-layered permeable reactive barrier (MPRB) to prevent and protect groundwater along traffic routes, especially in ecologically and naturally valuable areas, was developed following several field and laboratory investigations conducted in the Department of Geotechnical Engineering of the Warsaw University of Life Sciences. In accordance with the guidelines of the Interstate Technology & Regulatory Council for the selection of reactive materials, numerous laboratory and field investigations should be performed to determine the environmental conditions, type and concentrations of the contaminants, and the physical-chemical and permeability properties of the reactive materials. However, the deformation and strength properties of the reactive materials should be also considered in the design and evaluation of the safety conditions. In this paper, strength and deformation properties of silica spongolite, zeolite, and activated carbon were investigated using direct shear and oedometer tests. The laboratory test results were used in numerical calculations with the application of the finite element method. The aim of this study was to define the impact of the installation stages of a multi-layered permeable reactive barrier on the stability of a road embankment. Numerical analysis may prevent, reduce or eliminate the risk in the case of a breakdown during the construction or/and exploitation of a PRB.

Mapping the Fluid Pathways and Permeability Barriers of a Large Gas Hydrate Reservoir

Science.gov (United States)

Campbell, A.; Zhang, Y. L.; Sun, L. F.; Saleh, R.; Pun, W.; Bellefleur, G.; Milkereit, B.

2012-12-01

An understanding of the relationship between the physical properties of gas hydrate saturated sedimentary basins aids in the detection, exploration and monitoring one of the world's upcoming energy resources. A large gas hydrate reservoir is located in the MacKenzie Delta of the Canadian Arctic and geophysical logs from the Mallik test site are available for the gas hydrate stability zone (GHSZ) between depths of approximately 850 m to 1100 m. The geophysical data sets from two neighboring boreholes at the Mallik test site are analyzed. Commonly used porosity logs, as well as nuclear magnetic resonance, compressional and Stoneley wave velocity dispersion logs are used to map zones of elevated and severely reduced porosity and permeability respectively. The lateral continuity of horizontal permeability barriers can be further understood with the aid of surface seismic modeling studies. In this integrated study, the behavior of compressional and Stoneley wave velocity dispersion and surface seismic modeling studies are used to identify the fluid pathways and permeability barriers of the gas hydrate reservoir. The results are compared with known nuclear magnetic resonance-derived permeability values. The aim of investigating this heterogeneous medium is to map the fluid pathways and the associated permeability barriers throughout the gas hydrate stability zone. This provides a framework for an understanding of the long-term dissociation of gas hydrates along vertical and horizontal pathways, and will improve the knowledge pertaining to the production of such a promising energy source.

Intestinal epithelial barrier function and tight junction proteins with heat and exercise

DEFF Research Database (Denmark)

Dokladny, Karol; Zuhl, Micah N; Moseley, Pope L

2016-01-01

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or "leaky" intestinal tight junction barrier allows augmented perme...

Cytokine Tuning of Intestinal Epithelial Function

Directory of Open Access Journals (Sweden)

Caroline Andrews

2018-06-01

Full Text Available The intestine serves as both our largest single barrier to the external environment and the host of more immune cells than any other location in our bodies. Separating these potential combatants is a single layer of dynamic epithelium composed of heterogeneous epithelial subtypes, each uniquely adapted to carry out a subset of the intestine’s diverse functions. In addition to its obvious role in digestion, the intestinal epithelium is responsible for a wide array of critical tasks, including maintaining barrier integrity, preventing invasion by microbial commensals and pathogens, and modulating the intestinal immune system. Communication between these epithelial cells and resident immune cells is crucial for maintaining homeostasis and coordinating appropriate responses to disease and can occur through cell-to-cell contact or by the release or recognition of soluble mediators. The objective of this review is to highlight recent literature illuminating how cytokines and chemokines, both those made by and acting on the intestinal epithelium, orchestrate many of the diverse functions of the intestinal epithelium and its interactions with immune cells in health and disease. Areas of focus include cytokine control of intestinal epithelial proliferation, cell death, and barrier permeability. In addition, the modulation of epithelial-derived cytokines and chemokines by factors such as interactions with stromal and immune cells, pathogen and commensal exposure, and diet will be discussed.

Astrocyte–endothelial interactions and blood–brain barrier permeability*

Science.gov (United States)

Abbott, N Joan

2002-01-01

The blood–brain barrier (BBB) is formed by brain endothelial cells lining the cerebral microvasculature, and is an important mechanism for protecting the brain from fluctuations in plasma composition, and from circulating agents such as neurotransmitters and xenobiotics capable of disturbing neural function. The barrier also plays an important role in the homeostatic regulation of the brain microenvironment necessary for the stable and co-ordinated activity of neurones. The BBB phenotype develops under the influence of associated brain cells, especially astrocytic glia, and consists of more complex tight junctions than in other capillary endothelia, and a number of specific transport and enzyme systems which regulate molecular traffic across the endothelial cells. Transporters characteristic of the BBB phenotype include both uptake mechanisms (e.g. GLUT-1 glucose carrier, L1 amino acid transporter) and efflux transporters (e.g. P-glycoprotein). In addition to a role in long-term barrier induction and maintenance, astrocytes and other cells can release chemical factors that modulate endothelial permeability over a time-scale of seconds to minutes. Cell culture models, both primary and cell lines, have been used to investigate aspects of barrier induction and modulation. Conditioned medium taken from growing glial cells can reproduce some of the inductive effects, evidence for involvement of diffusible factors. However, for some features of endothelial differentiation and induction, the extracellular matrix plays an important role. Several candidate molecules have been identified, capable of mimicking aspects of glial-mediated barrier induction of brain endothelium; these include TGFβ, GDNF, bFGF, IL-6 and steroids. In addition, factors secreted by brain endothelial cells including leukaemia inhibitory factor (LIF) have been shown to induce astrocytic differentiation. Thus endothelium and astrocytes are involved in two-way induction. Short-term modulation of brain

Permeable barrier materials for strontium immobilization: Unsaturated flow apparatus determination of hydraulic conductivity -- Column sorption experiments

International Nuclear Information System (INIS)

Moody, T.E.; Conca, J.

1996-09-01

Selected materials were tested to emulate a permeable barrier and to examine the (1) capture efficiency of these materials relating to the immobilization of strontium-90 and hexavalent chromium (Cr 6+ ) in Hanford Site groundwater; and (2) hydraulic conductivity of the barrier material relative to the surrounding area. The emplacement method investigated was a permeable reactive barrier to treat contaminated groundwater as it passes through the barrier. The hydraulic conductivity function was measured for each material, and retardation column experiments were performed for each material. Measurements determining the hydraulic conductivity at unsaturated through saturated water content were executed using the Unsaturated Flow Apparatus

Lactobacillus frumenti Facilitates Intestinal Epithelial Barrier Function Maintenance in Early-Weaned Piglets

Science.gov (United States)

Hu, Jun; Chen, Lingli; Zheng, Wenyong; Shi, Min; Liu, Liu; Xie, Chunlin; Wang, Xinkai; Niu, Yaorong; Hou, Qiliang; Xu, Xiaofan; Xu, Baoyang; Tang, Yimei; Zhou, Shuyi; Yan, Yiqin; Yang, Tao; Ma, Libao; Yan, Xianghua

2018-01-01

Increased intestinal epithelial barrier function damages caused by early weaning stress have adverse effects on swine health and feed utilization efficiency. Probiotics have emerged as the promising antibiotic alternatives used for intestinal barrier function damage prevention. Our previous data showed that Lactobacillus frumenti was identified as a predominant Lactobacillus in the intestinal microbiota of weaned piglets. However, whether the intestinal epithelial barrier function in piglets was regulated by L. frumenti is still unclear. Here, piglets received a PBS vehicle or PBS suspension (2 ml, 108 CFU/ml) containing the L. frumenti by oral gavage once a day during the period of 6–20 days of age prior to early weaning. Our data demonstrated that oral administration of L. frumenti significantly improved the intestinal mucosal integrity and decreased the serum endotoxin and D-lactic acid levels in early-weaned piglets (26 days of age). The intestinal tight junction proteins (including ZO-1, Occludin, and Claudin-1) were significantly up-regulated by L. frumenti administration. The serum immunoglobulin G (IgG) levels, intestinal secretory immunoglobulin A (sIgA) levels, and interferon-γ (IFN-γ) levels were significantly increased by L. frumenti administration. Furthermore, our data revealed that oral administration of L. frumenti significantly increased the relative abundances of health-promoting microbes (including L. frumenti, Lactobacillus gasseri LA39, Parabacteroides distasonis, and Kazachstania telluris) and decreased the relative abundances of opportunistic pathogens (including Desulfovibrio desulfuricans and Candida humilis). Functional alteration of the intestinal bacterial community by L. frumenti administration was characterized by the significantly increased fatty acids and protein metabolism and decreased diseases-associated metabolic pathways. These findings suggest that L. frumenti facilitates intestinal epithelial barrier function maintenance

Chronic air-flow limitation does not increase respiratory epithelial permeability assessed by aerosolized solute, but smoking does

International Nuclear Information System (INIS)

Huchon, G.J.; Russell, J.A.; Barritault, L.G.; Lipavsky, A.; Murray, J.F.

1984-01-01

To determine the separate influences of smoking and severe air-flow limitation on aerosol deposition and respiratory epithelial permeability, we studied 26 normal nonsmokers, 12 smokers without airway obstruction, 12 nonsmokers with chronic obstructive pulmonary disease (COPD), and 11 smokers with COPD. We aerosolized 99mTc-labeled diethylene triamine pentaacetic acid to particles approximately 1 micron activity median aerodynamic diameter. Levels of radioactivity were plotted semilogarithmically against time to calculate clearance as percent per minute. The distribution of radioactivity was homogeneous in control subjects and in smokers, but patchy in both groups with COPD. No difference was found between clearances of the control group (1.18 +/- 0.31% min-1), and nonsmoker COPD group (1.37 +/- 0.82% min-1), whereas values in smokers without COPD (4.00 +/- 1.70% min-1) and smokers with COPD (3.62 +/- 2.88% min-1) were significantly greater than in both nonsmoking groups. We conclude that (1) small particles appear to deposit peripherally, even with severe COPD; (2) respiratory epithelial permeability is normal in nonsmokers with COPD; (3) smoking increases permeability by a mechanism unrelated to air-flow limitation

Myosin Light Chain Kinase Mediates Intestinal Barrier Disruption following Burn Injury

Science.gov (United States)

Chen, Chuanli; Wang, Pei; Su, Qin; Wang, Shiliang; Wang, Fengjun

2012-01-01

Background Severe burn injury results in the loss of intestinal barrier function, however, the underlying mechanism remains unclear. Myosin light chain (MLC) phosphorylation mediated by MLC kinase (MLCK) is critical to the pathophysiological regulation of intestinal barrier function. We hypothesized that the MLCK-dependent MLC phosphorylation mediates the regulation of intestinal barrier function following burn injury, and that MLCK inhibition attenuates the burn-induced intestinal barrier disfunction. Methodology/Principal Findings Male balb/c mice were assigned randomly to either sham burn (control) or 30% total body surface area (TBSA) full thickness burn without or with intraperitoneal injection of ML-9 (2 mg/kg), an MLCK inhibitor. In vivo intestinal permeability to fluorescein isothiocyanate (FITC)-dextran was measured. Intestinal mucosa injury was assessed histologically. Tight junction proteins ZO-1, occludin and claudin-1 was analyzed by immunofluorescent assay. Expression of MLCK and phosphorylated MLC in ileal mucosa was assessed by Western blot. Intestinal permeability was increased significantly after burn injury, which was accompanied by mucosa injury, tight junction protein alterations, and increase of both MLCK and MLC phosphorylation. Treatment with ML-9 attenuated the burn-caused increase of intestinal permeability, mucosa injury, tight junction protein alterations, and decreased MLC phosphorylation, but not MLCK expression. Conclusions/Significance The MLCK-dependent MLC phosphorylation mediates intestinal epithelial barrier dysfunction after severe burn injury. It is suggested that MLCK-dependent MLC phosphorylation may be a critical target for the therapeutic treatment of intestinal epithelial barrier disruption after severe burn injury. PMID:22529961

Cultured alveolar epithelial cells from septic rats mimic in vivo septic lung.

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Taylor S Cohen

2010-06-01

Full Text Available Sepsis results in the formation of pulmonary edema by increasing in epithelial permeability. Therefore we hypothesized that alveolar epithelial cells isolated from septic animals develop tight junctions with different protein composition and reduced barrier function relative to alveolar epithelial cells from healthy animals. Male rats (200-300 g were sacrificed 24 hours after cecal ligation and double puncture (2CLP or sham surgery. Alveolar epithelial cells were isolated and plated on fibronectin-coated flexible membranes or permeable, non-flexible transwell substrates. After a 5 day culture period, cells were either lysed for western analysis of tight junction protein expressin (claudin 3, 4, 5, 7, 8, and 18, occludin, ZO-1, and JAM-A and MAPk (JNK, ERK, an p38 signaling activation, or barrier function was examined by measuring transepithelial resistance (TER or the flux of two molecular tracers (5 and 20 A. Inhibitors of JNK (SP600125, 20 microM and ERK (U0126, 10 microM were used to determine the role of these pathways in sepsis induced epithelial barrier dysfunction. Expression of claudin 4, claudin 18, and occludin was significantly lower, and activation of JNK and ERK signaling pathways was significantly increased in 2CLP monolayers, relative to sham monolayers. Transepithelial resistance of the 2CLP monolayers was reduced significantly compared to sham (769 and 1234 ohm-cm(2, respectively, however no significant difference in the flux of either tracer was observed. Inhibition of ERK, not JNK, significantly increased TER and expression of claudin 4 in 2CLP monolayers, and prevented significant differences in claudin 18 expression between 2CLP and sham monolayers. We conclude that alveolar epithelial cells isolated from septic animals form confluent monolayers with impaired barrier function compared to healthy monolayers, and inhibition of ERK signaling partially reverses differences between these monolayers. This model provides a unique

Ozone exposure increases respiratory epithelial permeability in humans

International Nuclear Information System (INIS)

Kehrl, H.R.; Vincent, L.M.; Kowalsky, R.J.; Horstman, D.H.; O'Neil, J.J.; McCartney, W.H.; Bromberg, P.A.

1987-01-01

Ozone is a respiratory irritant that has been shown to cause an increase in the permeability of the respiratory epithelium in animals. We used inhaled aerosolized /sup 99m/Tc-labeled diethylene triamine pentacetic acid (/sup 99m/Tc-DTPA) to investigate whether human respiratory epithelial permeability is similarly affected by exposure to ozone. In a randomized, crossover double-blinded study, 8 healthy, nonsmoking young men were exposed for 2 h to purified air and 0.4 ppm ozone while performing intermittent high intensity treadmill exercise (minute ventilation = 66.8 L/min). SRaw and FVC were measured before and at the end of exposures. Seventy-five minutes after the exposures, the pulmonary clearance of /sup 99m/Tc-DTPA was measured by sequential posterior lung imaging with a computer-assisted gamma camera. Ozone exposure caused respiratory symptoms in all 8 subjects and was associated with a 14 +/- 2.8% (mean +/- SEM) decrement in FVC (p less than 0.001) and a 71 +/- 22% increase in SRaw (p = 0.04). Compared with the air exposure day, 7 of the 8 subjects showed increased /sup 99m/Tc-DTPA clearance after the ozone exposure, with the mean value increasing from 0.59 +/- 0.08 to 1.75 +/- 0.43%/min (p = 0.03). These data show that ozone exposure sufficient to produce decrements in the pulmonary function of human subjects also causes an increase in /sup 99m/Tc-DTPA clearance

Stress induces endotoxemia and low-grade inflammation by increasing barrier permeability

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Karin ede Punder

2015-05-01

Full Text Available Chronic non-communicable diseases (NCDs are the leading causes of work absence, disability and mortality worldwide. Most of these diseases are associated with low-grade inflammation. Here we hypothesize that stresses (defined as homeostatic disturbances can induce low-grade inflammation by increasing the availability of water, sodium and energy-rich substances to meet the increased metabolic demand induced by the stressor. One way of triggering low-grade inflammation is by increasing intestinal barrier permeability through activation of various components of the stress system. Although beneficial to meet the demands necessary during stress, increased intestinal barrier permeability also raises the possibility of the translocation of bacteria and their toxins across the intestinal lumen into the blood circulation. In combination with modern life-style factors, the increase in bacteria/bacterial toxin translocation arising from a more permeable intestinal wall causes a low-grade inflammatory state. We support this hypothesis with numerous studies finding associations with NCDs and markers of endotoxemia, suggesting that this process plays a pivotal and perhaps even a causal role in the development of low-grade inflammation and its related diseases.

Abnormal blood-brain barrier permeability in normal appearing white matter in multiple sclerosis investigated by MRI

DEFF Research Database (Denmark)

Cramer, Stig Præstekær; Simonsen, Helle Juhl; Frederiksen, Jette Lautrup Battistini

2013-01-01

To investigate whether blood-brain barrier (BBB) permeability is disrupted in normal appearing white matter in MS patients, when compared to healthy controls and whether it is correlated with MS clinical characteristics.......To investigate whether blood-brain barrier (BBB) permeability is disrupted in normal appearing white matter in MS patients, when compared to healthy controls and whether it is correlated with MS clinical characteristics....

PERMEABLE REACTIVE BARRIERS FOR IN-SITU TREATMENT OF ARSENIC-CONTAMINATED GROUNDWATER

Science.gov (United States)

Laboratory and field research has shown that permeable reactive barriers (PRBs) containing a variety of materials can treat arsenic (As) contaminated groundwater. Sites where these PRBs are located include a mine tailings facility, fertilizer and chemical manufacturing sites, a...

Altered Blood-Brain Barrier Permeability in Patients With Systemic Lupus Erythematosus: A Novel Imaging Approach.

Science.gov (United States)

Gulati, Gaurav; Jones, Jordan T; Lee, Gregory; Altaye, Mekibib; Beebe, Dean W; Meyers-Eaton, Jamie; Wiley, Kasha; Brunner, Hermine I; DiFrancesco, Mark W

2017-02-01

To evaluate a safe, noninvasive magnetic resonance imaging (MRI) method to measure regional blood-brain barrier integrity and investigate its relationship with neurocognitive function and regional gray matter volume in juvenile-onset systemic lupus erythematosus (SLE). In this cross-sectional, case-control study, capillary permeability was measured as a marker of blood-brain barrier integrity in juvenile SLE patients and matched healthy controls, using a combination of arterial spin labeling and diffusion-weighted brain MRI. Regional gray matter volume was measured by voxel-based morphometry. Correlation analysis was done to investigate the relationship between regional capillary permeability and regional gray matter volume. Formal neurocognitive testing was completed (measuring attention, visuoconstructional ability, working memory, and psychomotor speed), and scores were regressed against regional blood-brain barrier integrity among juvenile SLE patients. Formal cognitive testing confirmed normal cognitive ability in all juvenile SLE subjects (n = 11) included in the analysis. Regional capillary permeability was negatively associated (P = 0.026) with neurocognitive performance concerning psychomotor speed in the juvenile SLE cohort. Compared with controls (n = 11), juvenile SLE patients had significantly greater capillary permeability involving Brodmann's areas 19, 28, 36, and 37 and caudate structures (P < 0.05 for all). There is imaging evidence of increased regional capillary permeability in juvenile SLE patients with normal cognitive performance using a novel noninvasive MRI technique. These blood-brain barrier outcomes appear consistent with functional neuronal network alterations and gray matter volume loss previously observed in juvenile SLE patients with overt neurocognitive deficits, supporting the notion that blood-brain barrier integrity loss precedes the loss of cognitive ability in juvenile SLE. Longitudinal studies are needed to

The influence of age on lung epithelial permeability

International Nuclear Information System (INIS)

Yang Minfu; Wang Daoyu; Liu Xiujie; He Zuoxiang; Wang Yuetao; Wang Shiwen

2007-01-01

Objective: The pulmonary clearance rate of aerosolized 99 Tc m -DTPA is a sensitive index for measurement of lung epithelial permeability (LEP). It is well established that LEP increases in some pathological conditions. However, little is known about the influence of age on LEP. Accordingly, the aim of this study was to evaluate the relationship between age and LEP in healthy nonsmokers. Methods: Seventy-nine healthy nonsmokers underwent 99 Tc m -DTPA inhalation imaging and pulmonary clearance index (k) was calculated. The following analyses were done: (1) To compare the difference of k values between aged (≥ 65 years) and non-aged ( 0 + b 1 x + b 2 x 2 + b 3 x 3 , y symbolized k values and x symbolized age). Conclusions: The data of LEP at different age groups showed negative correlation of LEP and age in non-smokers. This data might play an age-related reference data in investigating senescence and lung disease in non-smokers. (authors)

Changes in permeability of the alveolar-capillary barrier in firefighters.

Science.gov (United States)

Minty, B D; Royston, D; Jones, J G; Smith, D J; Searing, C S; Beeley, M

1985-09-01

The effect on alveolar-capillary barrier permeability of chronic exposure to a smoke produced by the partial combusion of diesel oil, paraffin, and wood was examined. An index of permeability was determined from the rate of transfer from the lung into the blood of the hydrophilic, labelled chelate 99mTc diethylene triamine penta-acetate (MW 492 dalton). The results of this test were expressed as the half time clearance of the tracer from the lung into the blood (T1/2 LB). The study was carried out at the Royal Naval Firefighting School, HMS Excellent. Permeability index was measured on seven non-smoking naval firefighting instructors who had worked at the school for periods of longer than two and a half months. Tests of airway function and carbon monoxide transfer factor were performed on four of these seven instructors. The results of the permeability index showed a T1/2 LB of 26 min +/- 5 (SEM) which differed significantly from that of normal non-smokers. By contrast all other lung function tests had values within the predicted normal range.

Translocation of SiO2-NPs across in vitro human bronchial epithelial monolayer

International Nuclear Information System (INIS)

George, I; Vranic, S; Boland, S; Borot, M C; Marano, F; Baeza-Squiban, A

2013-01-01

Safe development and application of nanotechnologies in many fields require better knowledge about their potential adverse effects on human health. Evidence of abilities of nanoparticles (NPs) to cross epithelial barriers and reach secondary organs via the bloodstream led us to investigate the translocation of SiO 2 NPs of 50 nm (50 nm-SiO 2 -NPs) across human bronchial epithelial cells that are primary targets after exposure to inhaled NPs. We quantified the translocation of fluorescently labelled SiO 2 NPs at non-cytotoxic concentrations (5 and 10 μg/cm 2 ) across Calu-3 epithelial monolayer. After 14 days in culture Calu-3 cells seeded onto 3 μm-polycarbonate Transwell membranes formed an efficient bronchial barrier assessed by measurement of the transepithelial electric resistance and quantification of the permeability of the monolayer. After 24 hours of exposure, we observed a significant translocation of NPs that was more important when the initial NP concentration decreased. Confocal microscopy observations revealed NP uptake by cells and an important NP retention inside the porous membrane. In conclusion, 50 nm-SiO 2 -NPs can cross the human bronchial epithelial barrier without affecting the integrity of the epithelial cell monolayer.

NO2 decreases paracellular resistance to ion and solute flow in alveolar epithelial monolayers

International Nuclear Information System (INIS)

Cheek, J.M.; Kim, K.J.; Crandall, E.D.

1990-01-01

Primary cultured monolayers of rat alveolar epithelial cells grown on tissue culture-treated Nuclepore filters were exposed to 2.5 ppm nitrogen dioxide NO 2 for 2-20 min. Changes in monolayer bioelectric properties and solute permeabilities were subsequently measured. Exposure to NO 2 produced a dose-dependent decrease in monolayer transepithelial electrical resistance (Rt), whereas monolayer short-circuit current was unaffected. Post-exposure monolayer permeability to 14 C-sucrose (which primarily crosses alveolar epithelium via the paracellular pathway) increased markedly. That for 3 H-glycerol (which permeates through both paracellular and transcellular pathways) increased to a lesser extent. Partial recovery of Rt and solute permeabilities was noted by 48-h post-exposure. The time courses of the decrease in Rt and increase in solute permeabilities were similar. These results suggest that NO 2 primarily impairs passive alveolar epithelial barrier functions in vitro, probably by altering intercellular junctions, and does not appear to directly affect cell membrane active ion transport processes. When correlated with results obtained from experimental approaches, studies of in vitro alveolar epithelial monolayers may facilitate investigations of dosimetry, sites, and mechanisms of oxidant injury in the lung

/GD-Tracker/ A software for blood-brain barrier permeability assessment\

Czech Academy of Sciences Publication Activity Database

Kala, David; Svoboda, Jan; Litvinec, Andrej; Pošusta, Antonín; Lisý, J.; Šulc, V.; Tomek, A.; Marusič, P.; Jiruška, Přemysl; Otáhal, Jakub

2017-01-01

Roč. 47, č. 2 (2017), s. 43-48 ISSN 0301-5491 R&D Projects: GA MZd(CZ) NV15-33115A; GA MŠk(CZ) LM2015062 Institutional support: RVO:67985823 Keywords : blood-brain barrier * MRI * Gd-DTPA * permeability * stroke * epileptogenesis * MATLAB * freeware * Gd-Tracker Subject RIV: FH - Neurology OBOR OECD: Neurosciences (including psychophysiology

Myosin light chain kinase mediates intestinal barrier disruption following burn injury.

Directory of Open Access Journals (Sweden)

Chuanli Chen

Full Text Available BACKGROUND: Severe burn injury results in the loss of intestinal barrier function, however, the underlying mechanism remains unclear. Myosin light chain (MLC phosphorylation mediated by MLC kinase (MLCK is critical to the pathophysiological regulation of intestinal barrier function. We hypothesized that the MLCK-dependent MLC phosphorylation mediates the regulation of intestinal barrier function following burn injury, and that MLCK inhibition attenuates the burn-induced intestinal barrier disfunction. METHODOLOGY/PRINCIPAL FINDINGS: Male balb/c mice were assigned randomly to either sham burn (control or 30% total body surface area (TBSA full thickness burn without or with intraperitoneal injection of ML-9 (2 mg/kg, an MLCK inhibitor. In vivo intestinal permeability to fluorescein isothiocyanate (FITC-dextran was measured. Intestinal mucosa injury was assessed histologically. Tight junction proteins ZO-1, occludin and claudin-1 was analyzed by immunofluorescent assay. Expression of MLCK and phosphorylated MLC in ileal mucosa was assessed by Western blot. Intestinal permeability was increased significantly after burn injury, which was accompanied by mucosa injury, tight junction protein alterations, and increase of both MLCK and MLC phosphorylation. Treatment with ML-9 attenuated the burn-caused increase of intestinal permeability, mucosa injury, tight junction protein alterations, and decreased MLC phosphorylation, but not MLCK expression. CONCLUSIONS/SIGNIFICANCE: The MLCK-dependent MLC phosphorylation mediates intestinal epithelial barrier dysfunction after severe burn injury. It is suggested that MLCK-dependent MLC phosphorylation may be a critical target for the therapeutic treatment of intestinal epithelial barrier disruption after severe burn injury.

Computational Prediction of Blood-Brain Barrier Permeability Using Decision Tree Induction

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Jörg Huwyler

2012-08-01

Full Text Available Predicting blood-brain barrier (BBB permeability is essential to drug development, as a molecule cannot exhibit pharmacological activity within the brain parenchyma without first transiting this barrier. Understanding the process of permeation, however, is complicated by a combination of both limited passive diffusion and active transport. Our aim here was to establish predictive models for BBB drug permeation that include both active and passive transport. A database of 153 compounds was compiled using in vivo surface permeability product (logPS values in rats as a quantitative parameter for BBB permeability. The open source Chemical Development Kit (CDK was used to calculate physico-chemical properties and descriptors. Predictive computational models were implemented by machine learning paradigms (decision tree induction on both descriptor sets. Models with a corrected classification rate (CCR of 90% were established. Mechanistic insight into BBB transport was provided by an Ant Colony Optimization (ACO-based binary classifier analysis to identify the most predictive chemical substructures. Decision trees revealed descriptors of lipophilicity (aLogP and charge (polar surface area, which were also previously described in models of passive diffusion. However, measures of molecular geometry and connectivity were found to be related to an active drug transport component.

Modelling water vapour permeability through atomic layer deposition coated photovoltaic barrier defects

Energy Technology Data Exchange (ETDEWEB)

Elrawemi, Mohamed, E-mail: Mohamed.elrawemi@hud.ac.uk [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Blunt, Liam; Fleming, Leigh [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Bird, David, E-mail: David.Bird@uk-cpi.com [Centre for Process Innovation Limited, Sedgefield, County Durham (United Kingdom); Robbins, David [Centre for Process Innovation Limited, Sedgefield, County Durham (United Kingdom); Sweeney, Francis [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom)

2014-11-03

Transparent barrier films such as Al{sub 2}O{sub 3} used for prevention of oxygen and/or water vapour permeation are the subject of increasing research interest when used for the encapsulation of flexible photovoltaic modules. However, the existence of micro-scale defects in the barrier surface topography has been shown to have the potential to facilitate water vapour ingress, thereby reducing cell efficiency and causing internal electrical shorts. Previous work has shown that small defects (≤ 3 μm lateral dimension) were less significant in determining water vapour ingress. In contrast, larger defects (≥ 3 μm lateral dimension) seem to be more detrimental to the barrier functionality. Experimental results based on surface topography segmentation analysis and a model presented in this paper will be used to test the hypothesis that the major contributing defects to water vapour transmission rate are small numbers of large defects. The model highlighted in this study has the potential to be used for gaining a better understanding of photovoltaic module efficiency and performance. - Highlights: • A model of water vapour permeation through barrier defects is presented. • The effect of the defects on the water vapour permeability is investigated. • Defect density correlates with water vapour permeability. • Large defects may dominate the permeation properties of the barrier film.

Effects of GSM modulated radio-frequency electromagnetic radiation on permeability of blood-brain barrier in male & female rats.

Science.gov (United States)

Sırav, Bahriye; Seyhan, Nesrin

2016-09-01

With the increased use of mobile phones, their biological and health effects have become more important. Usage of mobile phones near the head increases the possibility of effects on brain tissue. This study was designed to investigate the possible effects of pulse modulated 900MHz and 1800MHz radio-frequency radiation on the permeability of blood-brain barrier of rats. Study was performed with 6 groups of young adult male and female wistar albino rats. The permeability of blood-brain barrier to intravenously injected evans blue dye was quantitatively examined for both control and radio-frequency radiarion exposed groups. For male groups; Evans blue content in the whole brain was found to be 0.08±0.01mg% in the control, 0.13±0.03mg% in 900MHz exposed and 0.26±0.05mg% in 1800MHz exposed animals. In both male radio-frequency radiation exposed groups, the permeability of blood-brain barrier found to be increased with respect to the controls (pradiation exposure was found more effective on the male animals (p0.01). However 900MHz pulse modulated radio-frequency exposure was found effective on the permeability of blood-brain barrier of female animals. Results have shown that 20min pulse modulated radio-frequency radiation exposure of 900MHz and 1800MHz induces an effect and increases the permeability of blood-brain barrier of male rats. For females, 900MHz was found effective and it could be concluded that this result may due to the physiological differences between female and male animals. The results of this study suggest that mobile phone radation could lead to increase the permeability of blood-brain barrier under non-thermal exposure levels. More studies are needed to demonstrate the mechanisms of that breakdown. Copyright © 2015 Elsevier B.V. All rights reserved.

γδ T cells in homeostasis and host defence of epithelial barrier tissues

DEFF Research Database (Denmark)

Nielsen, Morten M.; Witherden, Deborah A.; Havran, Wendy L.

2017-01-01

Epithelial surfaces line the body and provide a crucial interface between the body and the external environment. Tissue-resident epithelial γδ T cells represent a major T cell population in the epithelial tissues and are ideally positioned to carry out barrier surveillance and aid in tissue...... homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body — namely, the epidermis and the intestine — and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity...

Permeability of EVOH Barrier Material Used in Automotive Applications: Metrology Development for Model Fuel Mixtures

Directory of Open Access Journals (Sweden)

Zhao Jing

2015-02-01

Full Text Available EVOH (Ethylene-Vinyl Alcohol materials are widely used in automotive applications in multi-layer fuel lines and tanks owing to their excellent barrier properties to aromatic and aliphatic hydrocarbons. These barrier materials are essential to limit environmental fuel emissions and comply with the challenging requirements of fast changing international regulations. Nevertheless, the measurement of EVOH permeability to model fuel mixtures or to their individual components is particularly difficult due to the complexity of these systems and their very low permeability, which can vary by several orders of magnitude depending on the permeating species and their relative concentrations. This paper describes the development of a new automated permeameter capable of taking up the challenge of measuring minute quantities as low as 1 mg/(m2.day for partial fluxes for model fuel mixtures containing ethanol, i-octane and toluene at 50°C. The permeability results are discussed as a function of the model fuel composition and the importance of EVOH preconditioning is emphasized for accurate permeability measurements. The last part focuses on the influence of EVOH conditioning on its mechanical properties and its microstructure, and further illustrates the specific behavior of EVOH in presence of ethanol oxygenated fuels. The new metrology developed in this work offers a new insight in the permeability properties of a leading barrier material and will help prevent the consequences of (bioethanol addition in fuels on environmental emissions through fuel lines and tanks.

Breakdown of mucin as barrier to digestive enzymes in the ischemic rat small intestine.

Directory of Open Access Journals (Sweden)

Marisol Chang

Full Text Available Loss of integrity of the epithelial/mucosal barrier in the small intestine has been associated with different pathologies that originate and/or develop in the gastrointestinal tract. We showed recently that mucin, the main protein in the mucus layer, is disrupted during early periods of intestinal ischemia. This event is accompanied by entry of pancreatic digestive enzymes into the intestinal wall. We hypothesize that the mucin-containing mucus layer is the main barrier preventing digestive enzymes from contacting the epithelium. Mucin breakdown may render the epithelium accessible to pancreatic enzymes, causing its disruption and increased permeability. The objective of this study was to investigate the role of mucin as a protection for epithelial integrity and function. A rat model of 30 min splanchnic arterial occlusion (SAO was used to study the degradation of two mucin isoforms (mucin 2 and 13 and two epithelial membrane proteins (E-cadherin and toll-like receptor 4, TLR4. In addition, the role of digestive enzymes in mucin breakdown was assessed in this model by luminal inhibition with acarbose, tranexamic acid, or nafamostat mesilate. Furthermore, the protective effect of the mucin layer against trypsin-mediated disruption of the intestinal epithelium was studied in vitro. Rats after SAO showed degradation of mucin 2 and fragmentation of mucin 13, which was not prevented by protease inhibition. Mucin breakdown was accompanied by increased intestinal permeability to FITC-dextran as well as degradation of E-cadherin and TLR4. Addition of mucin to intestinal epithelial cells in vitro protected against trypsin-mediated degradation of E-cadherin and TLR4 and reduced permeability of FITC-dextran across the monolayer. These results indicate that mucin plays an important role in the preservation of the mucosal barrier and that ischemia but not digestive enzymes disturbs mucin integrity, while digestive enzymes actively mediate epithelial cell

Surfactant-modified zeolites as permeable barriers to organic and inorganic groundwater contaminants

International Nuclear Information System (INIS)

Bowman, R.S.; Sullivan, E.J.

1995-01-01

We have shown in laboratory experiments that natural zeolites treated with hexadecyltrimethylammonium (HDTMA) are effective sorbents for nonpolar organics, inorganic cations, and inorganic anions. Due to their low cost (∼$0.75/kg) and granular nature, HDTMA-zeolites appear ideal candidates for reactive, permeable subsurface barriers. The HDTMA-zeolites are stable over a wide range of pH (3-13), ionic strength (1 M Cs + or Ca 2+ ), and in organic solvents. Surfactant-modified zeolites sorb nonpolar organics (benzene, toluene, xylene, chlorinated aliphatics) via a partitioning mechanism, inorganic cations (Pb 2+ ) via ion exchange and surface complexation, and inorganic anions (CrO 4 2- , SeO 4 2- , SO 4 2- ) via surface precipitation.The goal of this work is to demonstrate the use of surfactant-modified zeolite as a permeable barrier to ground water contaminants

Interferon-gamma increased epithelial barrier function via upregulating claudin-7 expression in human submandibular gland duct epithelium.

Science.gov (United States)

Abe, Ayumi; Takano, Kenichi; Kojima, Takashi; Nomura, Kazuaki; Kakuki, Takuya; Kaneko, Yakuto; Yamamoto, Motohisa; Takahashi, Hiroki; Himi, Tetsuo

2016-06-01

Tight junctions (TJs) are necessary for salivary gland function and may serve as indicators of salivary gland epithelial dysfunction. IgG4-related disease (IgG4-RD) is a newly recognized fibro-inflammatory condition which disrupts the TJ associated epithelial barrier. The salivary glands are one of the most frequently involved organs in IgG4-RD, however, changes of the TJ associated epithelial barrier in salivary gland duct epithelium is poorly understood. Here, we investigated the regulation and function of TJs in human submandibular gland ductal epithelial cells (HSDECs) in normal and IgG4-RD. We examined submandibular gland (SMG) tissue from eight control individuals and 22 patients with IgG4-RD and established an HSDEC culture system. Immunohistochemistry, immunocytochemistry, western blotting, and measurement of transepithelial electrical resistance (TER) were performed. Claudin-4, claudin-7, occludin, and JAM-A were expressed at the apical side of the duct epithelium in submandibular gland (SMG) tissue and at the cell borders in HSDECs of normal and IgG4-RD. The expression and distribution of TJs in SMG tissue were not different in control individuals and patients with IgG4-RD in vivo and in vitro. Although interferon-gamma (IFNγ) generally disrupts the integrity and function of TJs, as manifested by decreased epithelial barrier function, IFNγ markedly increased the epithelial barrier function of HSDECs via upregulation of claudin-7 expression in HSDECs from patients with IgG4-RD. This is the first report showing an IFNγ-dependent increase in epithelial barrier function in the salivary gland duct epithelium. Our results provide insights into the functional significance of TJs in salivary gland duct epithelium in physiological and pathological conditions, including IgG4-RD.

Protective Effects of Bifidobacterium on Intestinal Barrier Function in LPS-Induced Enterocyte Barrier Injury of Caco-2 Monolayers and in a Rat NEC Model.

Science.gov (United States)

Ling, Xiang; Linglong, Peng; Weixia, Du; Hong, Wei

2016-01-01

Zonulin protein is a newly discovered modulator which modulates the permeability of the intestinal epithelial barrier by disassembling intercellular tight junctions (TJ). Disruption of TJ is associated with neonatal necrotizing enterocolitis (NEC). It has been shown bifidobacterium could protect the intestinal barrier function and prophylactical administration of bifidobacterium has beneficial effects in NEC patients and animals. However, it is still unknown whether the zonulin is involved in the gut barrier dysfunction of NEC, and the protective mechanisms of bifidobacterium on intestinal barrier function are also not well understood. The present study aims to investigate the effects of bifidobacterium on intestinal barrier function, zonulin regulation, and TJ integrity both in LPS-induced enterocyte barrier injury of Caco-2 monolayers and in a rat NEC model. Our results showed bifidobacterium markedly attenuated the decrease in transepithelial electrical resistance and the increase in paracellular permeability in the Caco-2 monolayers treated with LPS (P zonulin release (P zonulin (P zonulin protein release and improvement of intestinal TJ integrity.

Fatty acids are required for epidermal permeability barrier function.

Science.gov (United States)

Mao-Qiang, M; Elias, P M; Feingold, K R

1993-08-01

The permeability barrier is mediated by a mixture of ceramides, sterols, and free fatty acids arranged as extracellular lamellar bilayers in the stratum corneum. Whereas prior studies have shown that cholesterol and ceramides are required for normal barrier function, definitive evidence for the importance of nonessential fatty acids is not available. To determine whether epidermal fatty acid synthesis also is required for barrier homeostasis, we applied 5-(tetradecyloxy)-2-furancarboxylic acid (TOFA), an inhibitor of acetyl CoA carboxylase, after disruption of the barrier by acetone or tape stripping. TOFA inhibits epidermal fatty acid by approximately 50% and significantly delays barrier recovery. Moreover, coadministration of palmitate with TOFA normalizes barrier recovery, indicating that the delay is due to a deficiency in bulk fatty acids. Furthermore, TOFA treatment also delays the return of lipids to the stratum corneum and results in abnormalities in the structure of lamellar bodies, the organelle which delivers lipid to the stratum corneum. In addition, the organization of secreted lamellar body material into lamellar bilayers within the stratum corneum interstices is disrupted by TOFA treatment. Finally, these abnormalities in lamellar body and stratum corneum membrane structure are corrected by coapplication of palmitate with TOFA. These results demonstrate a requirement for bulk fatty acids in barrier homeostasis. Thus, inhibiting the epidermal synthesis of any of the three key lipids that form the extracellular, lipid-enriched membranes of the stratum corneum results in an impairment in barrier homeostasis.

Lactobacillus protects the integrity of intestinal epithelial barrier damaged by pathogenic bacteria

Directory of Open Access Journals (Sweden)

Qinghua eYu

2015-03-01

Full Text Available Pathogens invade intestinal mucosal barrier through phagocytosis of antigen presenting cells (dendritic cell, microfold cells, or through the invasion into the intestinal epithelial directly. Some pathogens could damage the cell junction between epithelial cells and use the paracellular pathway as an entrance to invade. Moreover, some Lactobacillus could inhibit the adhesion of the pathogens and protect the integrity of the cell junction and mucosal barrier. This research focused on the potential therapeutic effect of Lactobacillus fructosus (L. fructosus C2 to attenuate ETEC K88 or S. typhimurium SL1344 induced changes to mucosal barrier. The results demonstrated that treatment of polarized Caco-2 cells with L. fructosus C2 reduced the permeation of dextran, and expression of IL-8, p-ERK and p-JNK when cells were infected with pathogenic bacteria. The findings indicated that L. fructosus C2 exerted a protective effect against the damage to the integrity of Caco-2 cells by ETEC or S. typhimurium infection.

The Pseudomonas aeruginosa Type III Translocon Is Required for Biofilm Formation at the Epithelial Barrier

DEFF Research Database (Denmark)

Tran, Cindy S; Rangel, Stephanie M; Almblad, Henrik

2014-01-01

Clinical infections by Pseudomonas aeruginosa, a deadly Gram-negative, opportunistic pathogen of immunocompromised hosts, often involve the formation of antibiotic-resistant biofilms. Although biofilm formation has been extensively studied in vitro on glass or plastic surfaces, much less is known...... about biofilm formation at the epithelial barrier. We have previously shown that when added to the apical surface of polarized epithelial cells, P. aeruginosa rapidly forms cell-associated aggregates within 60 minutes of infection. By confocal microscopy we now show that cell-associated aggregates...... a previously unappreciated function for the type III translocon in the formation of P. aeruginosa biofilms at the epithelial barrier and demonstrate that biofilms may form at early time points of infection....

The diffusion permeability to water of the rat blood-brain barrier

DEFF Research Database (Denmark)

Bolwig, T G; Lassen, N A

1975-01-01

The diffusion permeability to water of the rat blood-brain-barrier (BBB) was studied. Preliminary data obtained with the Oldendorf tissue uptake method (Oldendorf 1970) in seizure experiments suggested that the transfer from blood to brain of labelled water is diffusion-limited. More definite...... passage increased from 0.26 to 0.67 when the arterial carbon dioxide tension was changed from 15 to 85 mm Hg, a change increasing the cerebral blood flow about sixfold. This finding suggests that water does not pass the blood-brain barrier as freely as lipophilic gases....

A permeability barrier surrounds taste buds in lingual epithelia

Science.gov (United States)

Dando, Robin; Pereira, Elizabeth; Kurian, Mani; Barro-Soria, Rene; Chaudhari, Nirupa

2014-01-01

Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003–1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste. PMID:25209263

A permeability barrier surrounds taste buds in lingual epithelia.

Science.gov (United States)

Dando, Robin; Pereira, Elizabeth; Kurian, Mani; Barro-Soria, Rene; Chaudhari, Nirupa; Roper, Stephen D

2015-01-01

Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003-1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste. Copyright © 2015 the American Physiological Society.

The rights and wrongs of blood-brain barrier permeability studies

DEFF Research Database (Denmark)

Saunders, Norman R; Dreifuss, Jean-Jacques; Dziegielewska, Katarzyna M

2014-01-01

Careful examination of relevant literature shows that many of the most cherished concepts of the blood-brain barrier are incorrect. These include an almost mythological belief in its immaturity that is unfortunately often equated with absence or at least leakiness in the embryo and fetus....... The original concept of a blood-brain barrier is often attributed to Ehrlich; however, he did not accept that permeability of cerebral vessels was different from other organs. Goldmann is often credited with the first experiments showing dye (trypan blue) exclusion from the brain when injected systemically......, but not when injected directly into it. Rarely cited are earlier experiments of Bouffard and of Franke who showed methylene blue and trypan red stained all tissues except the brain. The term "blood-brain barrier" "Blut-Hirnschranke" is often attributed to Lewandowsky, but it does not appear in his papers...

Effects of topical application of aqueous solutions of hexoses on epidermal permeability barrier recovery rate after barrier disruption.

Science.gov (United States)

Denda, Mitsuhiro

2011-11-01

Previous studies have suggested that hexose molecules influence the stability of phospholipid bilayers. Therefore, the effects of topical application of all 12 stereoisomers of dextro-hexose on the epidermal barrier recovery rate after barrier disruption were evaluated. Immediately after tape stripping, 0.1 m aqueous solution of each hexose was applied on hairless mouse skin. Among the eight dextro-aldohexoses, topical application of altose, idose, mannose and talose accelerated the barrier recovery, while allose, galactose, glucose and gulose had no effect. Among the four dextro-ketohexoses, psicose, fructose, sorbose and tagatose all accelerated the barrier recovery. As the effects of hexoses on the barrier recovery rate appeared within 1 h, the mechanism is unlikely to be genomic. Instead, these hexoses may influence phase transition of the lipid bilayers of lamellar bodies and cell membrane, a crucial step in epidermal permeability barrier homeostasis. © 2011 John Wiley & Sons A/S.

The effects of hypoglycemic and alcoholic coma on the blood-brain barrier permeability

Science.gov (United States)

Yorulmaz, Hatice; Seker, Fatma Burcu; Oztas, Baria

2011-01-01

In this investigation, the effects of hypoglycemic coma and alcoholic coma on the blood-brain barrier (BBB) permeability have been compared. Female adult Wistar albino rats weighing 180-230 g were divided into three groups: Control group (n=8), Alcoholic Coma Group (n=18), and Hypoglycemic Coma group (n=12). The animals went into coma approximately 3-4 hours after insulin administration and 3-5 minutes after alcohol administration. Evans blue (4mL/kg) was injected intravenously as BBB tracer. It was observed that the alcoholic coma did not significantly increase the BBB permeability in any of the brain regions when compared to control group. Changes in BBB permeability were significantly increased by the hypoglycemic coma in comparison to the control group values (pcoma have different effects on the BBB permeability depending on the energy metabolism. PMID:21619558

Fluorescein isothiocyanate (FITC)-Dextran Extravasation as a Measure of Blood-Brain Barrier Permeability

Science.gov (United States)

Natarajan, Reka; Northrop, Nicole

2017-01-01

The blood-brain barrier (BBB) is formed in part by vascular endothelial cells that constitute the capillaries and microvessels of the brain. The function of this barrier is to maintain homeostasis within the brain microenvironment and buffer the brain from changes in the periphery. A dysfunction of the BBB would permit circulating molecules and pathogens typically restricted to the periphery to enter the brain and interfere with normal brain function. As increased permeability of the BBB is associated with several neuropathologies, it is important to have a reliable and sensitive method that determines BBB permeability and the degree of BBB disruption. A detailed protocol is presented for assessing the integrity of the BBB by transcardial perfusion of a 10,000 Da FITC labeled dextran molecule and its visualization to determine the degree of extravasation from brain microvessels. PMID:28398646

Connexin 26-mediated gap junctional intercellular communication suppresses paracellular permeability of human intestinal epithelial cell monolayers

International Nuclear Information System (INIS)

Morita, Hidekazu; Katsuno, Tatsuro; Hoshimoto, Aihiro; Hirano, Noriaki; Saito, Yasushi; Suzuki, Yasuo

2004-01-01

In some cell types, gap junctional intercellular communication (GJIC) is associated with tight junctions. The present study was performed to determine the roles of GJIC in regulation of the barrier function of tight junctions. Caco-2 human colonic cells were used as a monolayer model, and barrier function was monitored by measuring mannitol permeability and transepithelial electrical resistance (TER). The monolayers were chemically disrupted by treatment with oleic acid and taurocholic acid. Western blotting analyses were performed to evaluate the protein levels of connexins, which are components of gap junctional intercellular channels. Cx26 expression was detected in preconfluent Caco-2 cells, and its level increased gradually after the monolayer reached confluency. These results prompted us to examine whether overexpression of Cx26 affects barrier function. Monolayers of Caco-2 cells stably expressing Cx26 showed significantly lower mannitol permeability and higher TER than mock transfectants when the monolayers were chemically disrupted. The levels of claudin-4, an important component of tight junctions, were significantly increased in the stable Cx26 transfectant. These results suggest that Cx26-mediated GJIC may play a crucial role in enhancing the barrier function of Caco-2 cell monolayers

EDTA-assisted phytoextraction of heavy metals by turfgrass from municipal solid waste compost using permeable barriers and associated potential leaching risk.

Science.gov (United States)

Zhao, Shulan; Lian, Fei; Duo, Lian

2011-01-01

A column experiment with horizontal permeable barriers was conducted to investigate phytoextraction of heavy metals by Lolium perenne L. from municipal solid waste compost following EDTA application, as well as to study the effects of L. perenne and permeable barriers on preventing metal from leaching. In columns with barriers, EDTA addition yielded maximum concentrations of Cu, Zn and Pb of 155, 541 and 33.5 mg kg(-1) in shoot, respectively. This led to 4.2, 2.1 and 7.4 times higher concentrations of Cu, Zn and Pb compared to treatment with no chelating agent, respectively. In treatments with 10 mmol kg(-1) EDTA, the barriers reduced leaching of Cu, Zn and Pb by approximately three times, respectively, resulting in leaching of total initial Cu, Zn and Pb by 27.3%, 25.2% and 28.8%, respectively, after four times' irrigation. These results indicate that L. perenne and permeable barriers are effective to reduce leaching of heavy metals and minimize the risk of contaminating groundwater in EDTA-enhanced phytoremediation. Thus these findings highlight that turfgrass and permeable barriers can effectively prevent metal leaching. Copyright © 2010 Elsevier Ltd. All rights reserved.

Vocal Fold Epithelial Barrier in Health and Injury: A Research Review

Science.gov (United States)

Levendoski, Elizabeth Erickson; Leydon, Ciara; Thibeault, Susan L.

2014-01-01

Purpose: Vocal fold epithelium is composed of layers of individual epithelial cells joined by junctional complexes constituting a unique interface with the external environment. This barrier provides structural stability to the vocal folds and protects underlying connective tissue from injury while being nearly continuously exposed to potentially…

The Mechanisms and Quantification of the Selective Permeability in Transport Across Biological Barriers : the Example of Kyotorphin

NARCIS (Netherlands)

Serrano, Isa D.; Freire, Joao M.; Carvalho, Miguel V.; Neves, Mafalda; Melo, Manuel N.; Castanho, Miguel A. R. B.

2014-01-01

This paper addresses the mechanisms behind selective endothelial permeability and their regulations. The singular properties of each of the seven blood-tissues barriers. Then, it further revisits the physical, quantitative meaning of permeability, and the way it should be measured based on sound

Arsenic compromises conducting airway epithelial barrier properties in primary mouse and immortalized human cell cultures.

Directory of Open Access Journals (Sweden)

Cara L Sherwood

Full Text Available Arsenic is a lung toxicant that can lead to respiratory illness through inhalation and ingestion, although the most common exposure is through contaminated drinking water. Lung effects reported from arsenic exposure include lung cancer and obstructive lung disease, as well as reductions in lung function and immune response. As part of their role in innate immune function, airway epithelial cells provide a barrier that protects underlying tissue from inhaled particulates, pathogens, and toxicants frequently found in inspired air. We evaluated the effects of a five-day exposure to environmentally relevant levels of arsenic {<4μM [~300 μg/L (ppb] as NaAsO2} on airway epithelial barrier function and structure. In a primary mouse tracheal epithelial (MTE cell model we found that both micromolar (3.9 μM and submicromolar (0.8 μM arsenic concentrations reduced transepithelial resistance, a measure of barrier function. Immunofluorescent staining of arsenic-treated MTE cells showed altered patterns of localization of the transmembrane tight junction proteins claudin (Cl Cl-1, Cl-4, Cl-7 and occludin at cell-cell contacts when compared with untreated controls. To better quantify arsenic-induced changes in tight junction transmembrane proteins we conducted arsenic exposure experiments with an immortalized human bronchial epithelial cell line (16HBE14o-. We found that arsenic exposure significantly increased the protein expression of Cl-4 and occludin as well as the mRNA levels of Cl-4 and Cl-7 in these cells. Additionally, arsenic exposure resulted in altered phosphorylation of occludin. In summary, exposure to environmentally relevant levels of arsenic can alter both the function and structure of airway epithelial barrier constituents. These changes likely contribute to the observed arsenic-induced loss in basic innate immune defense and increased infection in the airway.

Permeability Barrier and Microstructure of Skin Lipid Membrane Models of Impaired Glucosylceramide Processing

OpenAIRE

Sochorov?, Michaela; Sta?kov?, Kl?ra; Pullmannov?, Petra; Kov??ik, Andrej; Zbytovsk?, Jarmila; V?vrov?, Kate?ina

2017-01-01

Ceramide (Cer) release from glucosylceramides (GlcCer) is critical for the formation of the skin permeability barrier. Changes in ?-glucocerebrosidase (GlcCer?ase) activity lead to diminished Cer, GlcCer accumulation and structural defects in SC lipid lamellae; however, the molecular basis for this impairment is not clear. We investigated impaired GlcCer-to-Cer processing in human Cer membranes to determine the physicochemical properties responsible for the barrier defects. Minor impairment (...

Permeable Barrier Materials for Strontium Immobilization: - UFA Determination of Hydraulic Conductivity. - Column Sorption Experiments

National Research Council Canada - National Science Library

Moody, T

1996-01-01

Selected materials were tested to emulate a permeable barrier and to examine the: (1) capture efficiency of these materials relating to the immobilization of strontium-90 and hexavalent chromium in Hanford groundwater...

Blood brain barrier permeability and tPA-mediated neurotoxicity

Science.gov (United States)

Nassar, Taher; Yarovoi, Sergey; Rayan, Anwar; Lamensdorf, Itschak; Karakoveski, Michael; Vadim, Polianski; Fanne, Rami Abu; Jamal, Mahmud; Cines, Douglas B.; Higazi, Abd Al-Roof

2015-01-01

Tissue type plasminogen activator (tPA) induces neuronal apoptosis, disrupt the blood-brain-barrier (BBB), and promotes dilation of the cerebral vasculature. The timing, sequence and contributions of these and other deleterious effects of tPA and their contribution to post-ischemic brain damage after stroke, have not been fully elucidated. To dissociate the effects of tPA on BBB permeability, cerebral vasodilation and protease-dependent pathways, we developed several tPA mutants and PAI-1 derived peptides constructed by computerized homology modeling of tPA. Our data show that intravenous administration of human tPA to rats increases BBB permeability through a non-catalytic process, which is associated with reversible neurotoxicity, brain damage, edema, mortality and contributes significantly to its brief therapeutic window. Furthermore, our data show that inhibiting the effect of tPA on BBB function without affecting its catalytic activity, improves outcome and significantly extends its therapeutic window in mechanical as well as thromboembolic models of stroke. PMID:20060006

Identification of multi-drug resistant Pseudomonas aeruginosa clinical isolates that are highly disruptive to the intestinal epithelial barrier

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Shevchenko Olga

2006-06-01

Full Text Available Abstract Background Multi-drug resistant Pseudomonas aeruginosa nosocomial infections are increasingly recognized worldwide. In this study, we focused on the virulence of multi-drug resistant clinical strains P. aeruginosa against the intestinal epithelial barrier, since P. aeruginosa can cause lethal sepsis from within the intestinal tract of critically ill and immuno-compromised patients via mechanisms involving disruption of epithelial barrier function. Methods We screened consecutively isolated multi-drug resistant P. aeruginosa clinical strains for their ability to disrupt the integrity of human cultured intestinal epithelial cells (Caco-2 and correlated these finding to related virulence phenotypes such as adhesiveness, motility, biofilm formation, and cytotoxicity. Results Results demonstrated that the majority of the multi-drug resistant P. aeruginosa clinical strains were attenuated in their ability to disrupt the barrier function of cultured intestinal epithelial cells. Three distinct genotypes were found that displayed an extreme epithelial barrier-disrupting phenotype. These strains were characterized and found to harbor the exoU gene and to display high swimming motility and adhesiveness. Conclusion These data suggest that detailed phenotypic analysis of the behavior of multi-drug resistant P. aeruginosa against the intestinal epithelium has the potential to identify strains most likely to place patients at risk for lethal gut-derived sepsis. Surveillance of colonizing strains of P. aeruginosa in critically ill patients beyond antibiotic sensitivity is warranted.

Desmoglein 2 regulates the intestinal epithelial barrier via p38 mitogen-activated protein kinase.

Science.gov (United States)

Ungewiß, Hanna; Vielmuth, Franziska; Suzuki, Shintaro T; Maiser, Andreas; Harz, Hartmann; Leonhardt, Heinrich; Kugelmann, Daniela; Schlegel, Nicolas; Waschke, Jens

2017-07-24

Intestinal epithelial barrier properties are maintained by a junctional complex consisting of tight junctions (TJ), adherens junctions (AJ) and desmosomes. Desmoglein 2 (Dsg2), an adhesion molecule of desmosomes and the only Dsg isoform expressed in enterocytes, is required for epithelial barrier properties and may contribute to barrier defects in Crohn's disease. Here, we identified extradesmosomal Dsg2 on the surface of polarized enterocytes by Triton extraction, confocal microscopy, SIM and STED. Atomic force microscopy (AFM) revealed Dsg2-specific binding events along the cell border on the surface of enterocytes with a mean unbinding force of around 30pN. Binding events were blocked by an inhibitory antibody targeting Dsg2 which under same conditions activated p38MAPK but did not reduce cell cohesion. In enterocytes deficient for Dsg2, p38MAPK activity was reduced and both barrier integrity and reformation were impaired. Dsc2 rescue did not restore p38MAPK activity indicating that Dsg2 is required. Accordingly, direct activation of p38MAPK in Dsg2-deficient cells enhanced barrier reformation demonstrating that Dsg2-mediated activation of p38MAPK is crucial for barrier function. Collectively, our data show that Dsg2, beside its adhesion function, regulates intestinal barrier function via p38MAPK signalling. This is in contrast to keratinocytes and points towards tissue-specific signalling functions of desmosomal cadherins.

Correlation between oral drug absorption in humans and apparent drug permeability coefficients in human intestinal epithelial (Caco-2) cells

International Nuclear Information System (INIS)

Artursson, P.; Karlsson, J.

1991-01-01

Monolayers of a well differentiated human intestinal epithelial cell line, Caco-2, were used as a model to study passive drug absorption across the intestinal epithelium. Absorption rate constants (expressed as apparent permeability coefficients) were determined for 20 drugs and peptides with different structural properties. The permeability coefficients ranged from approximately 5 x 10 - 8 to 5 x 10 - 5 cm/s. A good correlation was obtained between data on oral absorption in humans and the results in the Caco-2 model. Drugs that are completely absorbed in humans had permeability coefficients greater than 1 x 10 - 6 cm/s. Drugs that are absorbed to greater than 1% but less than 100% had permeability coefficients of 0.1-1.0 x 10 - 6 cm/s while drugs and peptides that are absorbed to less than 1% had permeability coefficients of less than or equal to 1 x 10 - 7 cm/s. The results indicate that Caco-2 monolayers can be used as a model for studies on intestinal drug absorption

Oxidation of trichloroethylene, toluene, and ethanol vapors by a partially saturated permeable reactive barrier

Science.gov (United States)

Mahmoodlu, Mojtaba G.; Hassanizadeh, S. Majid; Hartog, Niels; Raoof, Amir

2014-08-01

The mitigation of volatile organic compound (VOC) vapors in the unsaturated zone largely relies on the active removal of vapor by ventilation. In this study we considered an alternative method involving the use of solid potassium permanganate to create a horizontal permeable reactive barrier for oxidizing VOC vapors. Column experiments were carried out to investigate the oxidation of trichloroethylene (TCE), toluene, and ethanol vapors using a partially saturated mixture of potassium permanganate and sand grains. Results showed a significant removal of VOC vapors due to the oxidation. We found that water saturation has a major effect on the removal capacity of the permeable reactive layer. We observed a high removal efficiency and reactivity of potassium permanganate for all target compounds at the highest water saturation (Sw = 0.6). A change in pH within the reactive layer reduced oxidation rate of VOCs. The use of carbonate minerals increased the reactivity of potassium permanganate during the oxidation of TCE vapor by buffering the pH. Reactive transport of VOC vapors diffusing through the permeable reactive layer was modeled, including the pH effect on the oxidation rates. The model accurately described the observed breakthrough curve of TCE and toluene vapors in the headspace of the column. However, miscibility of ethanol in water in combination with produced water during oxidation made the modeling results less accurate for ethanol. A linear relationship was found between total oxidized mass of VOC vapors per unit volume of permeable reactive layer and initial water saturation. This behavior indicates that pH changes control the overall reactivity and longevity of the permeable reactive layer during oxidation of VOCs. The results suggest that field application of a horizontal permeable reactive barrier can be a viable technology against upward migration of VOC vapors through the unsaturated zone.

A Tracer Test to Characterize Treatment of TCE in a Permeable Reactive Barrier

Science.gov (United States)

A tracer test was conducted to characterize the flow of ground water surrounding a permeable reactive barrier constructed with plant mulch (a biowall) at the OU-1 site on Altus Air Force Base, Oklahoma. This biowall is intended to intercept and treat ground water contaminated by ...

Use of jet grouting to create a low permeability horizontal barrier below an incinerator ash landfill

International Nuclear Information System (INIS)

Furth, A.J.; Burke, G.K.; Deutsch, W.L. Jr.

1997-01-01

The City of Philadelphia's Division of Aviation (DOA) has begun construction of a new commuter runway, designated as Runway 8-26, at the Philadelphia International Airport. A portion of this runway will be constructed over a former Superfund site known as the Enterprise Avenue Landfill, which for many years was used to dispose of solid waste incinerator ash and other hazardous materials. The site was clay capped in the 1980's, but in order for the DOA to use the site, additional remediation was needed to meet US EPA final closure requirements. One component of the closure plan included installation of a low permeability horizontal barrier above a very thin (approximately 0.61 to 0.91 meters) natural clay stratum which underlies an approximately 1020 m 2 area of the landfill footprint so as to insure that a minimum 1.52 meter thick low permeability barrier exists beneath the entire 150,000 m 2 landfill. The new barrier was constructed using jet grouting techniques to achieve remote excavation and replacement of the bottom 0.91 meters of the waste mass with a low permeability grout. The grout was formulated to meet the low permeability, low elastic modulus and compressive strength requirements of the project design. This paper will discuss the advantages of using jet grouting for the work and details the development of the grout mixture, modeling of the grout zone under load, field construction techniques, performance monitoring and verification testing

γδ T cells in homeostasis and host defence of epithelial barrier tissues.

Science.gov (United States)

Nielsen, Morten M; Witherden, Deborah A; Havran, Wendy L

2017-12-01

Epithelial surfaces line the body and provide a crucial interface between the body and the external environment. Tissue-resident epithelial γδ T cells represent a major T cell population in the epithelial tissues and are ideally positioned to carry out barrier surveillance and aid in tissue homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body - namely, the epidermis and the intestine - and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity and repair, host homeostasis and protection in the context of the symbiotic relationship with the microbiome and during pathogen clearance. Finally, we describe epithelium-specific butyrophilin-like molecules and briefly review their emerging role in selectively shaping and regulating epidermal and intestinal γδ T cell repertoires.

Prediction of Placental Barrier Permeability: A Model Based on Partial Least Squares Variable Selection Procedure

Directory of Open Access Journals (Sweden)

Yong-Hong Zhang

2015-05-01

Full Text Available Assessing the human placental barrier permeability of drugs is very important to guarantee drug safety during pregnancy. Quantitative structure–activity relationship (QSAR method was used as an effective assessing tool for the placental transfer study of drugs, while in vitro human placental perfusion is the most widely used method. In this study, the partial least squares (PLS variable selection and modeling procedure was used to pick out optimal descriptors from a pool of 620 descriptors of 65 compounds and to simultaneously develop a QSAR model between the descriptors and the placental barrier permeability expressed by the clearance indices (CI. The model was subjected to internal validation by cross-validation and y-randomization and to external validation by predicting CI values of 19 compounds. It was shown that the model developed is robust and has a good predictive potential (r2 = 0.9064, RMSE = 0.09, q2 = 0.7323, rp2 = 0.7656, RMSP = 0.14. The mechanistic interpretation of the final model was given by the high variable importance in projection values of descriptors. Using PLS procedure, we can rapidly and effectively select optimal descriptors and thus construct a model with good stability and predictability. This analysis can provide an effective tool for the high-throughput screening of the placental barrier permeability of drugs.

Impedance-based cell monitoring: barrier properties and beyond

Directory of Open Access Journals (Sweden)

Benson Kathrin

2013-01-01

Full Text Available Abstract In multicellular organisms epithelial and endothelial cells form selective permeable interfaces between tissue compartments of different chemical compositions. Tight junctions which connect adjacent cells, control the passage of molecules across the barrier and, in addition, facilitate active transport processes. The cellular barriers are not static but can be deliberately modulated by exposure to specific external stimuli. In vitro models representing the essential absorption barriers of the body are nowadays available, thus allowing investigation of the parameters that control permeability as well as transport processes across those barriers. Independent of the origin of the barrier forming cells, techniques are needed to quantify their barrier integrity. One simple assay is to measure the permeability for given hydrophilic substrates possessing different molecular weights like sucrose or dextrans. However, this technique is time-consuming and labor-intensive. Moreover, radioactive or fluorescently-labeled substrates are needed to allow easy analytical detection. Finally, if transport processes are investigated, the standard permeant may interfere with the transport process under investigation or might even alter the barrier integrity by itself. Thus, independent, non-invasive techniques are needed to quantify the barrier integrity continuously during the experiment. Such techniques are available and are mainly based on the measurement of the transendothelial or transepithelial electrical resistance (TEER of barrier forming cells grown on porous membranes. Simple devices using two sets of electrodes (so-called Voltohmeters are widely used. In addition, an easy-to-use physical technique called impedance spectroscopy allows the continuous analysis of both the TEER and the electrical capacitance giving additional information about the barrier properties of cells grown on permeable membranes. This technique is useful as a quality control

Long-term Performance of Permeable Reactive Barriers Using Zero-valent Iron: An Evaluation at Two Sites

National Research Council Canada - National Science Library

Wilkin, Richard T; Puls, Robert W; Sewell, Guy W

2002-01-01

Research described in this research brief explores the geochemical and microbiological processes occurring within zero-valent iron treatment zones in permeable reactive barriers that may contribute...

De novo expression of sodium-glucose cotransporter SGLT2 in Bowman’s capsule coincides with replacement of parietal epithelial cell layer with proximal tubule-like epithelium

OpenAIRE

Tabatabai, Niloofar M.; North, Paula E.; Regner, Kevin R.; Kumar, Suresh N.; Duris, Christine B.; Blodgett, Amy B.

2014-01-01

In kidney nephron, parietal epithelial cells line the Bowman’s capsule and function as a permeability barrier for the glomerular filtrate. Bowman’s capsule cells with proximal tubule epithelial morphology have been found. However, the effects of tubular metaplasia in Bowman’s capsule on kidney function remain poorly understood. Sodium-glucose cotransporter 2 (SGLT2) plays a major role in reabsorption of glucose in the kidney and is expressed on brush border membrane of epithelial cells in the...

Relative permeability of the endothelium and epithelium of rabbit lungs

International Nuclear Information System (INIS)

Effros, R.M.; Mason, G.R.; Silverman, P.; Hukkanen, J.

1986-01-01

Electron micrographic studies of lungs suggest that the epithelial cells are more tightly joined than the underlying endothelium, and macromolecules penetrate the endothelium more readily than the epithelium. Comparisons of epithelial and endothelial permeability to small molecules have been based upon the relative rates at which solutes traverse the alveolar-capillary barrier in fluid filled lungs and those at which they equilibrate across the capillaries in air-filled lungs. Because the former process is much slower than the latter, it has been concluded that the epithelium is less permeable to small solutes than the endothelium. However this difference may be related to inadequate access of solutes to airway surfaces. In this study, solute losses from the vascular space were compared to those from the airspace in perfused, fluid-filled rabbit lungs. 36 Cl - and 125 I - were lost from air-spaces almost twice as rapidly as 22 Na + . In contrast, the endothelium is equally permeable to 22 Na + and these anions. Loss of 3 H-mannitol from the perfusate resembled that of 22 Na + for about 30 minutes, after which diffusion of 3 H-mannitol into the tissue nearly ceased. These observations suggest that the epithelium is more permselective than the endothelium. By resisting solute and water transport, the epithelium tends to prevent alveolar flooding and confines edema to the interstitium, where it is less likely to interfere with gas exchange

Phasic changes of blood-brain-barrier permeability in mice after non-uniform γ-irradiation

International Nuclear Information System (INIS)

Ushakov, I.B.

1986-01-01

Early changes of blood-brain barrier (BBB) permeability in mice after irradiation of head or body were studied. The experiments were carried out on male-mice F 1 (C57xCBA) with medium mass of 25.1±0.8 g, irradiated in 2.58 C/kg dose to head or body. Correlation between BBB permeability decrease and radiation disease clinical manifestation frequency is determined. In early periods after irradiation, minimum two phases of BBB permeability change were observed: increase (0-2 h) and decrease (2-6 h) of permeability. BBB changes were expressed in later periods (24-120 h) as well. BBB permeability progressively increased after irradiation of head. According to the author's suggestion, this phenomenon gives evidence of generalization of vessel permeability disturbance (primarily of brain vessels) which leads to complete BBB dysfunction and to the loss of this morphofunctional formation's ability to perform its protective function. When considering BBB permeability connection with the frequency of neurologycal sign (tremor, ataxia) appearance, reversible correlation between these indicators is marked, beginning with the first period. The presence connection of fluid redistribution between blood and internal brain medium (edema growth) with the development of clinical manifestations of CNS affection is suggested

Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability.

Science.gov (United States)

Payne, Allison H; Hawryluk, Gregory W; Anzai, Yoshimi; Odéen, Henrik; Ostlie, Megan A; Reichert, Ethan C; Stump, Amanda J; Minoshima, Satoshi; Cross, Donna J

2017-12-01

Spinal cord injury (SCI) affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound (MRgFUS) as a non-invasive approach to increase permeability in the blood-spinal cord barrier (BSCB). We hypothesize that localized, controlled sonoporation of the BSCB by MRgFUS will aid delivery of therapeutics to the injury. Here, we report our preliminary findings for the ability of MRgFUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRgFUS blood spinal cord barrier opening. Then, in normal rats, MRgFUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles.

Cell-permeable intrinsic cellular inhibitors of apoptosis protect and rescue intestinal epithelial cells from radiation-induced cell death

International Nuclear Information System (INIS)

Matsuzaki-Horibuchi, Shiori; Yasuda, Takeshi; Sakaguchi, Nagako; Yamaguchi, Yoshihiro; Akashi, Makoto

2015-01-01

One of the important mechanisms for gastrointestinal (GI) injury following high-dose radiation exposure is apoptosis of epithelial cells. X-linked inhibitor of apoptosis (XIAP) and cellular IAP2 (cIAP2) are intrinsic cellular inhibitors of apoptosis. In order to study the effects of exogenously added IAPs on apoptosis in intestinal epithelial cells, we constructed bacterial expression plasmids containing genes of XIAP (full-length, BIR2 domain and BIR3-RING domain with and without mutations of auto-ubiquitylation sites) and cIAP2 proteins fused to a protein-transduction domain (PTD) derived from HIV-1 Tat protein (TAT) and purified these cell-permeable recombinant proteins. When the TAT-conjugated IAPs were added to rat intestinal epithelial cells IEC6, these proteins were effectively delivered into the cells and inhibited apoptosis, even when added after irradiation. Our results suggest that PTD-mediated delivery of IAPs may have clinical potential, not only for radioprotection but also for rescuing the GI system from radiation injuries. (author)

Autoradiographic study of the permeability characteristics of the small intestine

Energy Technology Data Exchange (ETDEWEB)

Kingham, J G.C.; Baker, J H; Loehry, C A [Royal Victoria Hospital, Bournemouth (UK)

1978-02-01

This autoradiographic study demonstrates the distribution of a range of small solutes and macromolecules in the mucosa of the guinea-pig small intestine after intracardiac injection. The substances investigated were: /sup 14/C-urea, /sup 3/H-mannose, /sup 3/H-inulin, and /sup 125/I polyvinylpyrrolidone (PVP). Small bowel biopsies were taken at intervals from one to 60 minutes after injection and the tissues processed for autoradiography. Light microscopic examination of the autoradiographs showed that the compartmental distribution depended on the molecular size of the substances being studied. Urea and mannose, as small solutes, were uniformly distributed throughout the intravascular, extravascular, and epithelial compartments. Inulin was evenly distributed in the vessel lumen and extravascular space but there was a considerable drop in concentration in the epithelium. PVP exhibited the most marked gradients, the concentration being greatest in the vascular lumina, lower in the extravascular space, least in the epithelium. Thus there appear to be two barriers to macromolecular passage which are freely permeable to small solutes: the capillary wall and the epithelium. At a light microscopical level it was not possible to observe whether the limiting membrane of each of these barriers is the cell plasmalemmal membrane or the basement membrane. The selectivity of the epithelial barrier was greater than that of the capillary barrier.

Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease.

Science.gov (United States)

Lerner, Aaron; Matthias, Torsten

2015-06-01

The incidence of autoimmune diseases is increasing along with the expansion of industrial food processing and food additive consumption. The intestinal epithelial barrier, with its intercellular tight junction, controls the equilibrium between tolerance and immunity to non-self-antigens. As a result, particular attention is being placed on the role of tight junction dysfunction in the pathogenesis of AD. Tight junction leakage is enhanced by many luminal components, commonly used industrial food additives being some of them. Glucose, salt, emulsifiers, organic solvents, gluten, microbial transglutaminase, and nanoparticles are extensively and increasingly used by the food industry, claim the manufacturers, to improve the qualities of food. However, all of the aforementioned additives increase intestinal permeability by breaching the integrity of tight junction paracellular transfer. In fact, tight junction dysfunction is common in multiple autoimmune diseases and the central part played by the tight junction in autoimmune diseases pathogenesis is extensively described. It is hypothesized that commonly used industrial food additives abrogate human epithelial barrier function, thus, increasing intestinal permeability through the opened tight junction, resulting in entry of foreign immunogenic antigens and activation of the autoimmune cascade. Future research on food additives exposure-intestinal permeability-autoimmunity interplay will enhance our knowledge of the common mechanisms associated with autoimmune progression. Copyright © 2015. Published by Elsevier B.V.

Multivalent adhesion molecule 7 clusters act as signaling platform for host cellular GTPase activation and facilitate epithelial barrier dysfunction.

Directory of Open Access Journals (Sweden)

Jenson Lim

2014-09-01

Full Text Available Vibrio parahaemolyticus is an emerging bacterial pathogen which colonizes the gastrointestinal tract and can cause severe enteritis and bacteraemia. During infection, V. parahaemolyticus primarily attaches to the small intestine, where it causes extensive tissue damage and compromises epithelial barrier integrity. We have previously described that Multivalent Adhesion Molecule (MAM 7 contributes to initial attachment of V. parahaemolyticus to epithelial cells. Here we show that the bacterial adhesin, through multivalent interactions between surface-induced adhesin clusters and phosphatidic acid lipids in the host cell membrane, induces activation of the small GTPase RhoA and actin rearrangements in host cells. In infection studies with V. parahaemolyticus we further demonstrate that adhesin-triggered activation of the ROCK/LIMK signaling axis is sufficient to redistribute tight junction proteins, leading to a loss of epithelial barrier function. Taken together, these findings show an unprecedented mechanism by which an adhesin acts as assembly platform for a host cellular signaling pathway, which ultimately facilitates breaching of the epithelial barrier by a bacterial pathogen.

Discontinuous permeable adsorptive barrier design and cost analysis: a methodological approach to optimisation.

Science.gov (United States)

Santonastaso, Giovanni Francesco; Bortone, Immacolata; Chianese, Simeone; Di Nardo, Armando; Di Natale, Michele; Erto, Alessandro; Karatza, Despina; Musmarra, Dino

2017-09-19

The following paper presents a method to optimise a discontinuous permeable adsorptive barrier (PAB-D). This method is based on the comparison of different PAB-D configurations obtained by changing some of the main PAB-D design parameters. In particular, the well diameters, the distance between two consecutive passive wells and the distance between two consecutive well lines were varied, and a cost analysis for each configuration was carried out in order to define the best performing and most cost-effective PAB-D configuration. As a case study, a benzene-contaminated aquifer located in an urban area in the north of Naples (Italy) was considered. The PAB-D configuration with a well diameter of 0.8 m resulted the best optimised layout in terms of performance and cost-effectiveness. Moreover, in order to identify the best configuration for the remediation of the aquifer studied, a comparison with a continuous permeable adsorptive barrier (PAB-C) was added. In particular, this showed a 40% reduction of the total remediation costs by using the optimised PAB-D.

Measurement of Regional and Global Pulmonary Clearance of 99mTc-DTPA (Demethylamitriptylene-Acetate): An Index of Alveolar Epithelial Permeability

International Nuclear Information System (INIS)

Vaskova, Olivija

1996-01-01

The main purpose of this study has been introduction of a new method for alveoli-capillary permeability evaluation. Many reports pointed out to the altered transit of soluble particles through this barrier. From pathophysiological aspect the main interest is the elucidation of permeability's alteration in different pulmonary pathology. We decided to use for lung epithelial permeability measurements 99m Tc-DTPA inhaled aerosols and sequential assessment of its lung clearance. The aerosols were obtained using oxygen flow nebulizers with aerosols' generators Ultra Vent (Malinkrodt) and Venticis II (CIS bio international) that enabled as to get submicron particles. Oxygen flow between 9 and 11 liters per minute was used. Optimum images were obtained with 1480 MBq of inhaled aerosols at least 2 to 3 minutes. DTPA that was used for aerosols labeling had been produced in our Department and the results were compared with DTPA provided by CIS bio international. High correlation between both agents was proven. During the whole study ex tamper prepared radiopharmaceuticals were used and quality control was done using paper chromatography method. Acquisition was done in sitting position with gamma camera interfaced to a ADAC and Scintiview. The measurements lasted for 20 minutes. Data were stored on 64x64 matrices. Regions of interest over both lungs were drown and each one was divided in three segments: apical, medial, and basal. Using computer program curves of 99m Tc-DTPA lung clearance were derived. From the obtained time activity curves half-time of the global and the regional lung clearance was assessed. In the control group comprised of 32 healthy volunteers (non-smokers) we had got values, used after works as reference range. Our normal values for global clearance are: 68±5,5 min. for left whole lung, 68,1±6,5 min for right whole lung, and 49±7,7 min for apical, 66,9±8 min for middle, and 75,9±6,4 min basal regional lung clearance, and they are in keeping with the

Mathematical Modeling and Experimental Validation of Nanoemulsion-Based Drug Transport across Cellular Barriers.

Science.gov (United States)

Kadakia, Ekta; Shah, Lipa; Amiji, Mansoor M

2017-07-01

Nanoemulsions have shown potential in delivering drug across epithelial and endothelial cell barriers, which express efflux transporters. However, their transport mechanisms are not entirely understood. Our goal was to investigate the cellular permeability of nanoemulsion-encapsulated drugs and apply mathematical modeling to elucidate transport mechanisms and sensitive nanoemulsion attributes. Transport studies were performed in Caco-2 cells, using fish oil nanoemulsions and a model substrate, rhodamine-123. Permeability data was modeled using a semi-mechanistic approach, capturing the following cellular processes: endocytotic uptake of the nanoemulsion, release of rhodamine-123 from the nanoemulsion, efflux and passive permeability of rhodamine-123 in aqueous solution. Nanoemulsions not only improved the permeability of rhodamine-123, but were also less sensitive to efflux transporters. The model captured bidirectional permeability results and identified sensitive processes, such as the release of the nanoemulsion-encapsulated drug and cellular uptake of the nanoemulsion. Mathematical description of cellular processes, improved our understanding of transport mechanisms, such as nanoemulsions don't inhibit efflux to improve drug permeability. Instead, their endocytotic uptake, results in higher intracellular drug concentrations, thereby increasing the concentration gradient and transcellular permeability across biological barriers. Modeling results indicated optimizing nanoemulsion attributes like the droplet size and intracellular drug release rate, may further improve drug permeability.

Automated Impedance Tomography for Monitoring Permeable Reactive Barrier Health

Energy Technology Data Exchange (ETDEWEB)

LaBrecque, D J; Adkins, P L

2009-07-02

The objective of this research was the development of an autonomous, automated electrical geophysical monitoring system which allows for near real-time assessment of Permeable Reactive Barrier (PRB) health and aging and which provides this assessment through a web-based interface to site operators, owners and regulatory agencies. Field studies were performed at four existing PRB sites; (1) a uranium tailing site near Monticello, Utah, (2) the DOE complex at Kansas City, Missouri, (3) the Denver Federal Center in Denver, Colorado and (4) the Asarco Smelter site in East Helena, Montana. Preliminary surface data over the PRB sites were collected (in December, 2005). After the initial round of data collection, the plan was modified to include studies inside the barriers in order to better understand barrier aging processes. In September 2006 an autonomous data collection system was designed and installed at the EPA PRB and the electrode setups in the barrier were revised and three new vertical electrode arrays were placed in dedicated boreholes which were in direct contact with the PRB material. Final data were collected at the Kansas City, Denver and Monticello, Utah PRB sites in the fall of 2007. At the Asarco Smelter site in East Helena, Montana, nearly continuous data was collected by the autonomous monitoring system from June 2006 to November 2007. This data provided us with a picture of the evolution of the barrier, enabling us to examine barrier changes more precisely and determine whether these changes are due to installation issues or are normal barrier aging. Two rounds of laboratory experiments were carried out during the project. We conducted column experiments to investigate the effect of mineralogy on the electrical signatures resulting from iron corrosion and mineral precipitation in zero valent iron (ZVI) columns. In the second round of laboratory experiments we observed the electrical response from simulation of actual field PRBs at two sites: the

Epigalloccatechin-3-gallate Inhibits Ocular Neovascularization and Vascular Permeability in Human Retinal Pigment Epithelial and Human Retinal Microvascular Endothelial Cells via Suppression of MMP-9 and VEGF Activation

Directory of Open Access Journals (Sweden)

Hak Sung Lee

2014-08-01

Full Text Available Epigalloccatechin-3-gallate (EGCG is the main polyphenol component of green tea (leaves of Camellia sinensis. EGCG is known for its antioxidant, anti-inflammatory, antiviral, and anti-carcinogenic properties. Here, we identify EGCG as a new inhibitor of ocular angiogenesis and its vascular permeability. Matrix metalloproteinases (MMPs and vascular endothelial growth factor (VEGF play a key role in the processes of extracellular matrix (ECM remodeling and microvascular permeability during angiogenesis. We investigated the inhibitory effects of EGCG on ocular neovascularization and vascular permeability using the retina oriented cells and animal models induced by VEGF and alkaline burn. EGCG treatment significantly decreased mRNA and protein expression levels of MMP-9 in the presence of 12-O-tetradecanoylphorbol-13-acetate (TPA and tumor necrosis factor alpha (TNF-α in human retinal pigment epithelial cells (HRPECs. EGCG also effectively protected ARPE-19 cells from cell death and attenuated mRNA expressions of key angiogenic factors (MMP-9, VEGF, VEGF Receptor-2 by inhibiting generation of reactive oxygen species (ROS. EGCG significantly inhibited proliferation, vascular permeability, and tube formation in VEGF-induced human retinal microvascular endothelial cells (HRMECs. Furthermore, EGCG significantly reduced vascular leakage and permeability by blood-retinal barrier breakdown in VEGF-induced animal models. In addition, EGCG effectively limited upregulation of MMP-9 and platelet endothelial cell adhesion molecule (PECAM/CD31 on corneal neovascularization (CNV induced by alkaline burn. Our data suggest that MMP-9 and VEGF are key therapeutic targets of EGCG for treatment and prevention of ocular angiogenic diseases such as age-related macular degeneration, diabetic retinopathy, and corneal neovascularization.

Role of lipids in the formation and maintenance of the cutaneous permeability barrier.

Science.gov (United States)

Feingold, Kenneth R; Elias, Peter M

2014-03-01

The major function of the skin is to form a barrier between the internal milieu and the hostile external environment. A permeability barrier that prevents the loss of water and electrolytes is essential for life on land. The permeability barrier is mediated primarily by lipid enriched lamellar membranes that are localized to the extracellular spaces of the stratum corneum. These lipid enriched membranes have a unique structure and contain approximately 50% ceramides, 25% cholesterol, and 15% free fatty acids with very little phospholipid. Lamellar bodies, which are formed during the differentiation of keratinocytes, play a key role in delivering the lipids from the stratum granulosum cells into the extracellular spaces of the stratum corneum. Lamellar bodies contain predominantly glucosylceramides, phospholipids, and cholesterol and following the exocytosis of lamellar lipids into the extracellular space of the stratum corneum these precursor lipids are converted by beta glucocerebrosidase and phospholipases into the ceramides and fatty acids, which comprise the lamellar membranes. The lipids required for lamellar body formation are derived from de novo synthesis by keratinocytes and from extra-cutaneous sources. The lipid synthetic pathways and the regulation of these pathways are described in this review. In addition, the pathways for the uptake of extra-cutaneous lipids into keratinocytes are discussed. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias. Published by Elsevier B.V.

Bifidobacterium animalis ssp. lactis CNCM-I2494 Restores Gut Barrier Permeability in Chronically Low-Grade Inflamed Mice.

Science.gov (United States)

Martín, Rebeca; Laval, Laure; Chain, Florian; Miquel, Sylvie; Natividad, Jane; Cherbuy, Claire; Sokol, Harry; Verdu, Elena F; van Hylckama Vlieg, Johan; Bermudez-Humaran, Luis G; Smokvina, Tamara; Langella, Philippe

2016-01-01

Growing evidence supports the efficacy of many probiotic strains in the management of gastrointestinal disorders associated with deregulated intestinal barrier function and/or structure. In particular, bifidobacteria have been studied for their efficacy to both prevent and treat a broad spectrum of animal and/or human gut disorders. The aim of the current work was thus to evaluate effects on intestinal barrier function of Bifidobacterium animalis ssp. lactis CNCM-I2494, a strain used in fermented dairy products. A chronic dinitrobenzene sulfonic acid (DNBS)-induced low-grade inflammation model causing gut dysfunction in mice was used in order to study markers of inflammation, intestinal permeability, and immune function in the presence of the bacterial strain. In this chronic low-grade inflammation mice model several parameters pointed out the absence of an over active inflammation process. However, gut permeability, lymphocyte populations, and colonic cytokines were found to be altered. B. animalis ssp. lactis CNCM-I2494 was able to protect barrier functions by restoring intestinal permeability, colonic goblet cell populations, and cytokine levels. Furthermore, tight junction (TJ) proteins levels were also measured by qRT-PCR showing the ability of this strain to specifically normalize the level of several TJ proteins, in particular for claudin-4. Finally, B. lactis strain counterbalanced CD4(+) lymphocyte alterations in both spleen and mesenteric lymphoid nodes. It restores the Th1/Th2 ratio altered by the DNBS challenge (which locally augments CD4(+) Th1 cells) by increasing the Th2 response as measured by the increase in the production of major representative Th2 cytokines (IL-4, IL-5, and IL-10). Altogether, these data suggest that B. animalis ssp. lactis CNCM-I2494 may efficiently prevent disorders associated with increased barrier permeability.

EMMPRIN Modulates Epithelial Barrier Function through a MMP–Mediated Occludin Cleavage

Science.gov (United States)

Huet, Eric; Vallée, Benoit; Delbé, Jean; Mourah, Samia; Prulière-Escabasse, Virginie; Tremouilleres, Magali; Kadomatsu, Kenji; Doan, Serge; Baudouin, Christophe; Menashi, Suzanne; Gabison, Eric E.

2011-01-01

Dry eye is a common disease that develops as a result of alteration of tear fluid, leading to osmotic stress and a perturbed epithelial barrier. Matrix metalloproteinase-9 (MMP-9) may be important in dry eye disease, as its genetic knockout conferred resistance to the epithelial disruption. We show that extracellular matrix metalloproteinase inducer (EMMPRIN; also termed CD147), an inducer of MMP expression, participates in the pathogenesis of dry eye through MMP-mediated cleavage of occludin, an important component of tight junctions. EMMPRIN expression was increased on the ocular surface of dry eye patients and correlated with those of MMP-9. High osmolarity in cell culture, mimicking dry eye conditions, increased both EMMPRIN and MMP-9 and resulted in the disruption of epithelial junctions through the cleavage of occludin. Exogenously added recombinant EMMPRIN had similar effects that were abrogated in the presence of the MMP inhibitor marimastat. Membrane occludin immunostaining was markedly increased in the apical corneal epithelium of both EMMPRIN and MMP-9 knock-out mice. Furthermore, an inverse correlation between EMMPRIN and occludin membrane staining was consistently observed both in vitro and in vivo as a function of corneal epithelial cells differentiation. These data suggest a possible role of EMMPRIN in regulating the amount of occludin at the cell surface in homeostasis beyond pathological situations such as dry eye disease, and EMMPRIN may be essential for the formation and maintenance of organized epithelial structure. PMID:21777561

Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders

Science.gov (United States)

Kelly, John R.; Kennedy, Paul J.; Cryan, John F.; Dinan, Timothy G.; Clarke, Gerard; Hyland, Niall P.

2015-01-01

The emerging links between our gut microbiome and the central nervous system (CNS) are regarded as a paradigm shift in neuroscience with possible implications for not only understanding the pathophysiology of stress-related psychiatric disorders, but also their treatment. Thus the gut microbiome and its influence on host barrier function is positioned to be a critical node within the brain-gut axis. Mounting preclinical evidence broadly suggests that the gut microbiota can modulate brain development, function and behavior by immune, endocrine and neural pathways of the brain-gut-microbiota axis. Detailed mechanistic insights explaining these specific interactions are currently underdeveloped. However, the concept that a “leaky gut” may facilitate communication between the microbiota and these key signaling pathways has gained traction. Deficits in intestinal permeability may underpin the chronic low-grade inflammation observed in disorders such as depression and the gut microbiome plays a critical role in regulating intestinal permeability. In this review we will discuss the possible role played by the gut microbiota in maintaining intestinal barrier function and the CNS consequences when it becomes disrupted. We will draw on both clinical and preclinical evidence to support this concept as well as the key features of the gut microbiota which are necessary for normal intestinal barrier function. PMID:26528128

Accurate determination of blood–brain barrier permeability using dynamic contrast-enhanced T1-weighted MRI

DEFF Research Database (Denmark)

Cramer, Stig P; Larsson, Henrik B W

2014-01-01

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is increasingly used to estimate permeability in situations with subtle blood-brain barrier (BBB) leakage. However, the method's ability to differentiate such low values from zero is unknown, and no consensus exists on optimal selection...

Blood-brain barrier permeability and monocyte infiltration in experimental allergic encephalomyelitis : a quantitative MRI study

NARCIS (Netherlands)

Floris, S.; Blezer, E.L.A.; Schreibelt, Gerty; Dopp, E.; Pol, van der S.M.A.; Schadee-Eestermans, I.L.; Nicolaij, K.; Dijkstra, C.D.; Vries, de H.E.

2004-01-01

Enhanced cerebrovascular permeability and cellular infiltration mark the onset of early multiple sclerosis lesions. So far, the precise sequence of these events and their role in lesion formation and disease progression remain unknown. Here we provide quantitative evidence that blood–brain barrier

LONG-TERM GEOCHEMICAL BEHAVIOR OF A ZEROVALENT IRON PERMEABLE REACTIVE BARRIER FOR THE TREATMENT OF HEXAVALENT CHROMIUM IN GROUNDWATER

Science.gov (United States)

Passive, in-situ reactive barriers have proven to be viable, cost-effective systems for the remediation of Cr-contaminated groundwater at some sites. Permeable reactive barriers (PRBs) are installed in the flow-path of groundwater, most typically as vertical treatment walls. Re...

Lactobacillus reuteri strains protect epithelial barrier integrity of IPEC-J2 monolayers from the detrimental effect of enterotoxigenic Escherichia coli.

Science.gov (United States)

Karimi, Shokoufeh; Jonsson, Hans; Lundh, Torbjörn; Roos, Stefan

2018-01-01

Lactobacillus reuteri is an inhabitant of the gastrointestinal (GI) tract of mammals and birds and several strains of this species are known to be effective probiotics. The mechanisms by which L. reuteri confers its health-promoting effects are far from being fully understood, but protection of the mucosal barrier is thought to be important. Leaky gut is a state of abnormal intestinal permeability with implications for the pathophysiology of various gastrointestinal disorders. Enterotoxigenic Escherichia coli (ETEC) can invade the intestinal mucosa and induce changes in barrier function by producing enterotoxin or by direct invasion of the intestinal epithelium. Our hypothesis was that L. reuteri can protect the mucosal barrier, and the goal of the study was to challenge this hypothesis by monitoring the protective effect of L. reuteri strains on epithelial dysfunction caused by ETEC. Using an infection model based on the porcine intestinal cell line IPEC-J2, it was demonstrated that pretreatment of the cells with human-derived L. reuteri strains (ATCC PTA 6475, DSM 17938 and 1563F) and a rat strain (R2LC) reduced the detrimental effect of ETEC in a dose-dependent manner, as monitored by permeability of FITC-dextran and transepithelial electrical resistance (TEER). Moreover, the results revealed that ETEC upregulated proinflammatory cytokines IL-6 and TNFα and decreased expression of the shorter isoform of ZO-1 (187 kDa) and E-cadherin. In contrast, pretreatment with L. reuteri DSM 17938 and 1563F downregulated expression of IL-6 and TNFα, and led to an increase in production of the longer isoform of ZO-1 (195 kDa) and maintained E-cadherin expression. Interestingly, expression of ZO-1 (187 kDa) was preserved only when the infected cells were pretreated with strain 1563F. These findings demonstrate that L. reuteri strains exert a protective effect against ETEC-induced mucosal integrity disruption. © 2018 The Authors. Physiological Reports published by

The Effect of Ovariectomy and Estrogen on Penetrating Brain Arterioles and Blood-Brain Barrier Permeability

NARCIS (Netherlands)

Cipolla, Marilyn J.; Godfrey, Julie A.; Wiegman, Marchien J.

2009-01-01

Objective: We investigated the effect of estrogen replacement on the structure and function of penetrating brain arterioles (PA) and blood-brain barrier (BBB) permeability. Materials and Methods: Female ovariectomized Sprague-Dawley rats were replaced with estradiol (E-2) and estriol (E-3) (OVX + E;

Effects of in Utero Exposure of C57BL/6J Mice to 2,3,7,8-Tetrachlorodibenzo-p-dioxin on Epidermal Permeability Barrier Development and Function

Science.gov (United States)

Muenyi, Clarisse S.; Carrion, Sandra Leon; Jones, Lynn A.; Kennedy, Lawrence H.; Slominski, Andrzej T.

2014-01-01

Background: Development of the epidermal permeability barrier (EPB) is essential for neonatal life. Defects in this barrier are found in many skin diseases such as atopic dermatitis. Objective: We investigated the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the development and function of the EPB. Methods: Timed-pregnant C57BL/6J mice were gavaged with corn oil or TCDD (10 μg/kg body weight) on gestation day 12. Embryos were harvested on embryonic day (E) 15, E16, E17, and postnatal day (PND) 1. Results: A skin permeability assay showed that TCDD accelerated the development of the EPB, beginning at E15. This was accompanied by a significant decrease in transepidermal water loss (TEWL), enhanced stratification, and formation of the stratum corneum (SC). The levels of several ceramides were significantly increased at E15 and E16. PND1 histology revealed TCDD-induced acanthosis and epidermal hyperkeratosis. This was accompanied by disrupted epidermal tight junction (TJ) function, with increased dye leakage at the terminal claudin-1–staining TJs of the stratum granulosum. Because the animals did not have enhanced rates of TEWL, a commonly observed phenotype in animals with TJ defects, we performed tape-stripping. Removal of most of the SC resulted in a significant increase in TEWL in TCDD-exposed PND1 pups compared with their control group. Conclusions: These findings demonstrate that in utero exposure to TCDD accelerates the formation of an abnormal EPB with leaky TJs, warranting further study of environmental exposures, epithelial TJ integrity, and atopic disease. Citation: Muenyi CS, Leon Carrion S, Jones LA, Kennedy LH, Slominski AT, Sutter CH, Sutter TR. 2014. Effects of in utero exposure of C57BL/6J mice to 2,3,7,8-tetrachlorodibenzo-p-dioxin on epidermal permeability barrier development and function. Environ Health Perspect 122:1052–1058; http://dx.doi.org/10.1289/ehp.1308045 PMID:24904982

Gas permeability of bentonite barriers: development, construction and testing of a measurement system

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Heraldo Nunes Pitanga

Full Text Available Abstract This article proposes a testing device to quickly and reliably estimate the gas permeability of bentonite-based clay barriers used in landfill cover systems. The testing methodology is based on a transient gas flow regime that passes through the barrier, therefore not requiring the use of sophisticated equipment that aim to maintain constant differential pressure and measure the gas flow, common requirements for testing methods under a permanent flow regime. To confirm the feasibility of the proposed technique, tests were performed on a pure hydrated bentonite layer, which subsequently encompassed samples of geosynthetic clay liner (GCL at different moisture contents. Geosynthetic clay liners are often selected as a part of the barrier layer for cover systems in solid waste landfills to prevent infiltration of rainfall and migration of biogas into the atmosphere. The results confirmed the equipment reliability and differentiate the different responses of the gas flow barriers studied, considering their different compositions and different moistures.

Heavy metal uptake and leaching from polluted soil using permeable barrier in DTPA-assisted phytoextraction.

Science.gov (United States)

Zhao, Shulan; Shen, Zhiping; Duo, Lian

2015-04-01

Application of sewage sludge (SS) in agriculture is an alternative technique of disposing this waste. But unreasonable application of SS leads to excessive accumulation of heavy metals in soils. A column experiment was conducted to test the availability of heavy metals to Lolium perenne grown in SS-treated soils following diethylene triamine penta acetic acid (DTPA) application at rates of 0, 10 and 20 mmol kg(-1) soil. In order to prevent metal leaching in DTPA-assisted phytoextraction process, a horizontal permeable barrier was placed below the treated soil, and its effectiveness was also assessed. Results showed that DTPA addition significantly increased metal uptake by L. perenne shoots and metal leaching. Permeable barriers increased metal concentrations in plant shoots and effectively decreased metal leaching from the treated soil. Heavy metals in SS-treated soils could be gradually removed by harvesting L. perenne many times in 1 year and adding low dosage of DTPA days before each harvest.

Fifteen-year Assessment of a Permeable Reactive Barrier for Treatment of Chromate and Trichloroethylene in Groundwater

Science.gov (United States)

The fifteen-year performance of a granular iron, permeable reactive barrier (PRB; Elizabeth City, North Carolina) is reviewed with respect to contaminant treatment (hexavalent chromium and trichloroethylene) and hydraulic performance. Due to in-situ treatment of the chromium sou...

Convective diffusion of nanoparticles from the epithelial barrier toward regional lymph nodes.

Science.gov (United States)

Dukhin, Stanislav S; Labib, Mohamed E

2013-11-01

Drug delivery using nanoparticles as drug carriers has recently attracted the attention of many investigators. Targeted delivery of nanoparticles to the lymph nodes is especially important to prevent cancer metastasis or infection, and to diagnose disease stage. However, systemic injection of nanoparticles often results in organ toxicity because they reach and accumulate in all the lymph nodes in the body. An attractive strategy would be to deliver the drug-loaded nanoparticles to a subset of draining lymph nodes corresponding to a specific site or organ to minimize systemic toxicity. In this respect, mucosal delivery of nanoparticles to regional draining lymph nodes of a selected site creates a new opportunity to accomplish this task with minimal toxicity. One example is the delivery of nanoparticles from the vaginal lumen to draining lymph nodes to prevent the transmission of HIV in women. Other known examples include mucosal delivery of vaccines to induce immunity. In all cases, molecular and particle transport by means of diffusion and convective diffusion play a major role. The corresponding transport processes have common inherent regularities and are addressed in this review. Here we use nanoparticle delivery from the vaginal lumen to the lymph nodes as an example to address the many aspects of associated transport processes. In this case, nanoparticles penetrate the epithelial barrier and move through the interstitium (tissue) to the initial lymphatics until they finally reach the lymph nodes. Since the movement of interstitial liquid near the epithelial barrier is retarded, nanoparticle transport was found to take place through special foci present in the epithelium. Immediately after nanoparticles emerge from the foci, they move through the interstitium due to diffusion affected by convection (convective diffusion). Specifically, the convective transport of nanoparticles occurs due to their convection together with interstitial fluid through the

Removal of chromate in a permeable reactive barrier using zero-valent iron

DEFF Research Database (Denmark)

Kjeldsen, Peter; Locht, T

2002-01-01

Chromate is a commonly found groundwater contaminant. Permeable reactive barriers containing zero-valent iron as iron filings are able to remove the chromate by a combined reduction/precipitation reaction. However, due to the passivation of the reduction capability of the iron surfaces by the pre......). Mixing in sand had no significant enhancing effect on the removal capacity, in contrast to a pH adjustment of the groundwater to pH 4, which significantly increased the removal capacity....

Possible links between intestinal permeablity and food processing: a potential therapeutic niche for glutamine

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Jean Robert Rapin

2010-01-01

Full Text Available Increased intestinal permeability is a likely cause of various pathologies, such as allergies and metabolic or even cardiovascular disturbances. Intestinal permeability is found in many severe clinical situations and in common disorders such as irritable bowel syndrome. In these conditions, substances that are normally unable to cross the epithelial barrier gain access to the systemic circulation. To illustrate the potential harmfulness of leaky gut, we present an argument based on examples linked to protein or lipid glycation induced by modern food processing. Increased intestinal permeability should be largely improved by dietary addition of compounds, such as glutamine or curcumin, which both have the mechanistic potential to inhibit the inflammation and oxidative stress linked to tight junction opening. This brief review aims to increase physician awareness of this common, albeit largely unrecognized, pathology, which may be easily prevented or improved by means of simple nutritional changes.

Possible Links between Intestinal Permeablity and Food Processing: A Potential Therapeutic Niche for Glutamine

Science.gov (United States)

Rapin, Jean Robert; Wiernsperger, Nicolas

2010-01-01

Increased intestinal permeability is a likely cause of various pathologies, such as allergies and metabolic or even cardiovascular disturbances. Intestinal permeability is found in many severe clinical situations and in common disorders such as irritable bowel syndrome. In these conditions, substances that are normally unable to cross the epithelial barrier gain access to the systemic circulation. To illustrate the potential harmfulness of leaky gut, we present an argument based on examples linked to protein or lipid glycation induced by modern food processing. Increased intestinal permeability should be largely improved by dietary addition of compounds, such as glutamine or curcumin, which both have the mechanistic potential to inhibit the inflammation and oxidative stress linked to tight junction opening. This brief review aims to increase physician awareness of this common, albeit largely unrecognized, pathology, which may be easily prevented or improved by means of simple nutritional changes. PMID:20613941

Small intestine epithelial barrier function is compromised in pigs with low feed intake at weaning.

NARCIS (Netherlands)

Spreeuwenberg, M.A.; Verdonk, J.M.; Gaskins, H.R.; Verstegen, M.W.A.

2001-01-01

Compromising alterations in gastrointestinal architecture are common during the weaning transition of pigs. The relation between villous atrophy and epithelial barrier function at weaning is not well understood. This study evaluated in vitro transepithelial transport by Ussing metabolic chambers,

Evaluation of blood--brain barrier permeability changes in rhesus monkeys and man using 82Rb and positron emission tomography

International Nuclear Information System (INIS)

Yen, C.K.; Budinger, T.F.

1981-01-01

Dynamic positron tomography of the brain with 82 Rb, obtained from a portable generator [ 82 Sr (25 days) -- 82 Rb (76 sec)], provides a means of studying blood-brain barrier (BBB) permeability in physiological and clinical investigations. The BBB in rhesus monkeys was opened unilaterally by intracarotid infusion of 3 M urea. This osmotic barrier opening allowed entry into the brain of intravenously administered rubidium chloride. The BBB opening was demonstrated noninvasively using 82 Rb and positron emission tomography and corroborated by the accumulation of 86 Rb in tissue samples. Positron emission tomography studies can be repeated every 5 min and indicate that dynamic tomography or static imaging can be used to study BBB permeability changes induced by a wide variety of noxious stimuli. Brain tumors in human subjects are readily detected because of the usual BBB permeability disruption in and around the tumors

Effects of Lactobacillus johnsonii and Lactobacillus reuteri on gut barrier function and heat shock proteins in intestinal porcine epithelial cells.

Science.gov (United States)

Liu, Hao-Yu; Roos, Stefan; Jonsson, Hans; Ahl, David; Dicksved, Johan; Lindberg, Jan Erik; Lundh, Torbjörn

2015-04-01

Heat shock proteins (HSPs) are a set of highly conserved proteins that can serve as intestinal gate keepers in gut homeostasis. Here, effects of a probiotic, Lactobacillus rhamnosus GG (LGG), and two novel porcine isolates, Lactobacillus johnsonii strain P47-HY and Lactobacillus reuteri strain P43-HUV, on cytoprotective HSP expression and gut barrier function, were investigated in a porcine IPEC-J2 intestinal epithelial cell line model. The IPEC-J2 cells polarized on a permeable filter exhibited villus-like cell phenotype with development of apical microvilli. Western blot analysis detected HSP expression in IPEC-J2 and revealed that L. johnsonii and L. reuteri strains were able to significantly induce HSP27, despite high basal expression in IPEC-J2, whereas LGG did not. For HSP72, only the supernatant of L. reuteri induced the expression, which was comparable to the heat shock treatment, which indicated that HSP72 expression was more stimulus specific. The protective effect of lactobacilli was further studied in IPEC-J2 under an enterotoxigenic Escherichia coli (ETEC) challenge. ETEC caused intestinal barrier destruction, as reflected by loss of cell-cell contact, reduced IPEC-J2 cell viability and transepithelial electrical resistance, and disruption of tight junction protein zonula occludens-1. In contrast, the L. reuteri treatment substantially counteracted these detrimental effects and preserved the barrier function. L. johnsonii and LGG also achieved barrier protection, partly by directly inhibiting ETEC attachment. Together, the results indicate that specific strains of Lactobacillus can enhance gut barrier function through cytoprotective HSP induction and fortify the cell protection against ETEC challenge through tight junction protein modulation and direct interaction with pathogens. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines.

Science.gov (United States)

Drago, Sandro; El Asmar, Ramzi; Di Pierro, Mariarosaria; Grazia Clemente, Maria; Tripathi, Amit; Sapone, Anna; Thakar, Manjusha; Iacono, Giuseppe; Carroccio, Antonio; D'Agate, Cinzia; Not, Tarcisio; Zampini, Lucia; Catassi, Carlo; Fasano, Alessio

2006-04-01

Little is known about the interaction of gliadin with intestinal epithelial cells and the mechanism(s) through which gliadin crosses the intestinal epithelial barrier. We investigated whether gliadin has any immediate effect on zonulin release and signaling. Both ex vivo human small intestines and intestinal cell monolayers were exposed to gliadin, and zonulin release and changes in paracellular permeability were monitored in the presence and absence of zonulin antagonism. Zonulin binding, cytoskeletal rearrangement, and zonula occludens-1 (ZO-1) redistribution were evaluated by immunofluorescence microscopy. Tight junction occludin and ZO-1 gene expression was evaluated by real-time polymerase chain reaction (PCR). When exposed to gliadin, zonulin receptor-positive IEC6 and Caco2 cells released zonulin in the cell medium with subsequent zonulin binding to the cell surface, rearrangement of the cell cytoskeleton, loss of occludin-ZO1 protein-protein interaction, and increased monolayer permeability. Pretreatment with the zonulin antagonist FZI/0 blocked these changes without affecting zonulin release. When exposed to luminal gliadin, intestinal biopsies from celiac patients in remission expressed a sustained luminal zonulin release and increase in intestinal permeability that was blocked by FZI/0 pretreatment. Conversely, biopsies from non-celiac patients demonstrated a limited, transient zonulin release which was paralleled by an increase in intestinal permeability that never reached the level of permeability seen in celiac disease (CD) tissues. Chronic gliadin exposure caused down-regulation of both ZO-1 and occludin gene expression. Based on our results, we concluded that gliadin activates zonulin signaling irrespective of the genetic expression of autoimmunity, leading to increased intestinal permeability to macromolecules.

Aging and sex influence the permeability of the blood-brain barrier in the rat

International Nuclear Information System (INIS)

Saija, A.; Princi, P.; D'Amico, N.; De Pasquale, R.; Costa, G.

1990-01-01

The aim of the present study was to investigate the existence of aging- and sex-related alterations in the permeability of the blood-brain barrier (BBB) in the rat, by calculating a unidirectional blood-to-brain transfer constant (Ki) for the circulating tracer [ 14 C]-α-aminoisobutyric acid. The authors observed that: (a) the permeability of the BBB significantly increased within the frontal and temporo-parietal cortex, hypothalamus and cerebellum in 28-30 week old rats, in comparison with younger animals; (b) in several brain areas of female intact rats higher Ki values (even though not significantly different) were calculated at oestrus than at proestrus; (c) in 1-week ovariectomized rats there was a marked increase of Ki values at the level of the frontal, temporo-parietal and occipital cortex, cerebellum and brain-stem. One can speculate that aging and sex-related alterations in thee permeability of the BBB reflect respectively changes in brain neurochemical system activity and in plasma steroid hormone levels

Detection of alveolar epithelial injury by 99mTc-DTPA radioaerosol inhalation lung scan following blunt chest trauma

International Nuclear Information System (INIS)

Okudan, B.; Han, S.; Baldemir, M.; Yildiz, M.

2004-01-01

DTPA clearance rate is a reliable index of alveolar epithelial permeability, and is a highly sensitive marker of pulmonary epithelial damage, even of mild degree. In this study, 99m Tc-DTPA aerosol inhalation scintigraphy was used to assess the pulmonary epithelial membrane permeability and to investigate the possible application of this permeability value as an indicator of early alveolar or interstitial changes in patients with blunt chest trauma. A total of 26 patients was chest trauma (4 female, 22 male, 31-80 yrs, mean age; 53±13 yrs) who were referred to the emergency department in our hospital participated in this study. Technetium-99m diethylene triamine pentaacetic acid (DTPA) aerosol inhalation scintigraphy was performed on the first and thirtieth days after trauma. Clearance half times (T 1/2 ) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. On the first day, mean T 1/2 value of the whole lung was 63±19 minutes (min), and thirtieth day mean T 1/2 value was 67±21 min. On the first day, mean PI values of the lung and 30th day mean PI value were 0.60±0.05, and 0.63 ±0.05, respectively. Significant changes were observed in radioaerosol clearance and penetration indices. Following chest trauma, clearance of 99m Tc-DTPA increased owing to breakdown of the alveolar-capillary barrier. This increase in the epithelial permeability of the lung appears to be an early manifestation of lung disease that may lead to efficient therapy in the early phase. (author)

Relation between histamine release and dye permeability of pulmonary blood-air barrier in x-irradiated rat

Energy Technology Data Exchange (ETDEWEB)

Yamazaki, H [Kobe Univ. (Japan). School of Medicine

1976-04-01

The histamine-release kinetics and the influence of released histamine on the permeability of the pulmonary blood-air(BA) barrier during the early period after either whole-body or thoracic x irradiation of the rat were studied. Histamine contents of skin and lung of the irradiated rat decreased rapidly, reaching a minimum at 5 h, and this histamine depletion continued for at least 7 days. Conversely, in circulating blood histamine increased during the early period of 5 h and then decreased gradually. This early increase was linear up to 500R and then became saturated between 500 and 1,000R. Administration of polymixine B (5mg/100g body weight) to rats liberated histamine similarly. Rat sera containg histamine released soon after irradiation enhanced the capillary permeability of Evans blue(EB) in the guinea pig skin reaction, which was effectively countered by pretreatment of the guinea pig with anti-histaminic pyribenzamine (29..mu..g/100g body weight), but not by anti-serotonic chlorpromazine (0.3mg/100g body weight). Similarly, perhaps only the EB-bound serum albumin (EB-albumin), that was seen in alveolar perfusate, penetrated more through the pulmonary BA-barrier with increasing x-ray dose, in parallel with the increase in blood histamine. Pyribenzamine inhibited this effect effectively, but cysteamine (a radical scavenger) did so only partially. Thus, it seems possible that at soon after x irradiation the enhanced permeability of EB-albumin through the BA barrier of rat lung is due preferentially to the pharmacologic action of released histamine and subsidiarily to radiation damage to pulmonary cells.

Effects of propranolol and clonidine on brain edema, blood-brain barrier permeability, and endothelial glycocalyx disruption after fluid percussion brain injury in the rat

DEFF Research Database (Denmark)

Genét, Gustav Folmer; Bentzer, Peter; Hansen, Morten Bagge

2018-01-01

clonidine would decrease brain edema, blood-brain barrier permeability, and glycocalyx disruption at 24 hours after trauma. METHODS: We subjected 53 adult male Sprague-Dawley rats to lateral fluid percussion brain injury and randomized infusion with propranolol (n = 16), propranolol + clonidine (n = 16......), vehicle (n = 16), or sham (n = 5) for 24 hours. Primary outcome was brain water content at 24 hours. Secondary outcomes were blood-brain barrier permeability and plasma levels of syndecan-1 (glycocalyx disruption), cell damage (histone-complexed DNA fragments), epinephrine, norepinephrine, and animal.......555). We found no effect of propranolol and propranolol/clonidine on blood-brain barrier permeability and animal motor scores. Unexpectedly, propranolol and propranolol/clonidine caused an increase in epinephrine and syndecan-1 levels. CONCLUSION: This study does not provide any support for unselective...

Vascular endothelial growth factors enhance the permeability of the mouse blood-brain barrier.

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Shize Jiang

Full Text Available The blood-brain barrier (BBB impedes entry of many drugs into the brain, limiting clinical efficacy. A safe and efficient method for reversibly increasing BBB permeability would greatly facilitate central nervous system (CNS drug delivery and expand the range of possible therapeutics to include water soluble compounds, proteins, nucleotides, and other large molecules. We examined the effect of vascular endothelial growth factor (VEGF on BBB permeability in Kunming (KM mice. Human VEGF165 was administered to treatment groups at two concentrations (1.6 or 3.0 µg/mouse, while controls received equal-volume saline. Changes in BBB permeability were measured by parenchymal accumulation of the contrast agent Gd-DTPA as assessed by 7 T magnetic resonance imaging (MRI. Mice were then injected with Evans blue, sacrificed 0.5 h later, and perfused transcardially. Brains were removed, fixed, and sectioned for histological study. Both VEGF groups exhibited a significantly greater signal intensity from the cerebral cortex and basal ganglia than controls (P<0.001. Evans blue fluorescence intensity was higher in the parenchyma and lower in the cerebrovasculature of VEGF-treated animals compared to controls. No significant brain edema was observed by diffusion weighted MRI (DWI or histological staining. Exogenous application of VEGF can increase the permeability of the BBB without causing brain edema. Pretreatment with VEGF may be a feasible method to facilitate drug delivery into the CNS.

Transformation of Reactive Iron Minerals in a Permeable Reactive Barrier (Biowall) Used to Treat TCE in Groundwater

Science.gov (United States)

Abstract: Iron and sulfur reducing conditions are generally created in permeable reactive barrier (PRB) systems constructed for groundwater treatment, which usually leads to formation of iron sulfide phases. Iron sulfides have been shown to play an important role in degrading ch...

基于压水试验的深部煤层底板岩层阻渗性能研究∗%Study on permeability barrier performance of deep coal seam floor based on packer permeability test

Institute of Scientific and Technical Information of China (English)

孙晓倩; 张冬; 张新武; 王言剑

2014-01-01

In situ field packer permeability test,being a reliable method to obtain the param-eters of permeability barrier performance of strata,was used to explore this performance of deep coal seam floor. A large amount of measured data were obtained after the test on two layers of floor strata. The test results showed that these two layers of floor strata could not seep in initial state due to stronger barrier performance until the fracture and connection led to seepage. Co MPared with the first and repeated packer permeability tests on these two layers of floor strata, the variation of water pressure in measured pore was associated with that in water injection hole, but the seepage pressure in the first time was higher than that in second time,showing that the permeability barrier performance of strata turned weaker after first packer permeability test and was easy to form seepage. Using permeability coefficient and permeability barrier strength as in-dexes,the permeability barrier performance of floor strata has been quantitatively evaluated,and the results showed that the tested strata was characterized with high barrier performance and weak permeability.%原位现场压水试验是获取岩层阻渗性能参数的可靠方法，为探究某煤矿深部煤层底板阻渗能力，采用现场压水试验方法对底板两段岩层进行了测试并获取了大量的实测数据。结果分析表明：该底板两测试段岩层在原始状态均不导渗，阻渗性较强，直至压裂导通才形成导渗条件；对两段岩层均进行了初次和重复两个压水过程，对比两次试验可知，测渗孔水压力与注水孔水压力的关联变化趋势大致相同，但初次压水的起始导渗水压明显高于重复压水，表明在初次压水后岩层的阻渗能力降低，更易形成导渗；采用渗透系数和阻渗强度作为指标，对底板岩层的阻渗性能进行了量化评价，结果表明测试岩层表现出明显的高阻弱渗的特点。

Arctigenin from Fructus Arctii (Seed of Burdock) Reinforces Intestinal Barrier Function in Caco-2 Cell Monolayers

Science.gov (United States)

Shin, Hee Soon; Jung, Sun Young; Back, Su Yeon; Do, Jeong-Ryong; Shon, Dong-Hwa

2015-01-01

Fructus Arctii is used as a traditional herbal medicine to treat inflammatory diseases in oriental countries. This study aimed to investigate effect of F. Arctii extract on intestinal barrier function in human intestinal epithelial Caco-2 cells and to reveal the active component of F. Arctii. We measured transepithelial electrical resistance (TEER) value (as an index of barrier function) and ovalbumin (OVA) permeation (as an index of permeability) to observe the changes of intestinal barrier function. The treatment of F. Arctii increased TEER value and decreased OVA influx on Caco-2 cell monolayers. Furthermore, we found that arctigenin as an active component of F. Arctii increased TEER value and reduced permeability of OVA from apical to the basolateral side but not arctiin. In the present study, we revealed that F. Arctii could enhance intestinal barrier function, and its active component was an arctigenin on the functionality. We expect that the arctigenin from F. Arctii could contribute to prevention of inflammatory, allergic, and infectious diseases by reinforcing intestinal barrier function. PMID:26550018

Arctigenin from Fructus Arctii (Seed of Burdock Reinforces Intestinal Barrier Function in Caco-2 Cell Monolayers

Directory of Open Access Journals (Sweden)

Hee Soon Shin

2015-01-01

Full Text Available Fructus Arctii is used as a traditional herbal medicine to treat inflammatory diseases in oriental countries. This study aimed to investigate effect of F. Arctii extract on intestinal barrier function in human intestinal epithelial Caco-2 cells and to reveal the active component of F. Arctii. We measured transepithelial electrical resistance (TEER value (as an index of barrier function and ovalbumin (OVA permeation (as an index of permeability to observe the changes of intestinal barrier function. The treatment of F. Arctii increased TEER value and decreased OVA influx on Caco-2 cell monolayers. Furthermore, we found that arctigenin as an active component of F. Arctii increased TEER value and reduced permeability of OVA from apical to the basolateral side but not arctiin. In the present study, we revealed that F. Arctii could enhance intestinal barrier function, and its active component was an arctigenin on the functionality. We expect that the arctigenin from F. Arctii could contribute to prevention of inflammatory, allergic, and infectious diseases by reinforcing intestinal barrier function.

Protein kinase C-dependent signaling controls the midgut epithelial barrier to malaria parasite infection in anopheline mosquitoes.

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Nazzy Pakpour

Full Text Available Anopheline mosquitoes are the primary vectors of parasites in the genus Plasmodium, the causative agents of malaria. Malaria parasites undergo a series of complex transformations upon ingestion by the mosquito host. During this process, the physical barrier of the midgut epithelium, along with innate immune defenses, functionally restrict parasite development. Although these defenses have been studied for some time, the regulatory factors that control them are poorly understood. The protein kinase C (PKC gene family consists of serine/threonine kinases that serve as central signaling molecules and regulators of a broad spectrum of cellular processes including epithelial barrier function and immunity. Indeed, PKCs are highly conserved, ranging from 7 isoforms in Drosophila to 16 isoforms in mammals, yet none have been identified in mosquitoes. Despite conservation of the PKC gene family and their potential as targets for transmission-blocking strategies for malaria, no direct connections between PKCs, the mosquito immune response or epithelial barrier integrity are known. Here, we identify and characterize six PKC gene family members--PKCδ, PKCε, PKCζ, PKD, PKN, and an indeterminate conventional PKC--in Anopheles gambiae and Anopheles stephensi. Sequence and phylogenetic analyses of the anopheline PKCs support most subfamily assignments. All six PKCs are expressed in the midgut epithelia of A. gambiae and A. stephensi post-blood feeding, indicating availability for signaling in a tissue that is critical for malaria parasite development. Although inhibition of PKC enzymatic activity decreased NF-κB-regulated anti-microbial peptide expression in mosquito cells in vitro, PKC inhibition had no effect on expression of a panel of immune genes in the midgut epithelium in vivo. PKC inhibition did, however, significantly increase midgut barrier integrity and decrease development of P. falciparum oocysts in A. stephensi, suggesting that PKC

AAnti-leakage mechanism and effect of sodium aescinate on the permeability of blood-brain barrier

Directory of Open Access Journals (Sweden)

Ping GUO

2012-02-01

Full Text Available Objective  To study the anti-leakage mechanism and protective effect of sodium aescinate on the blood-brain barrier of rats acutely exposed to hypoxia. Methods  Seventy-five healthy SD rats were randomly divided into 3 groups (25 each: normoxic control (NC, simple hypoxic (SH and drug treated (DT group. Acute hypoxia brain edema rat model was established by a simulation of acute high-altitude hypoxia for 5 days. The cerebral water content was determined by dry-wet method. The permeability of the blood-brain barrier (BBB was evaluated by Evans blue (EB method. The pathological change of the brain was detected by HE staining. The state of BBB tight junction (TJ and ultrastructures of the brain tissues were observed by lanthanum nitrate tracer method under transmission electron microscope (TEM. Protein and mRNA expression of Occludin, Zo-1 and Claudin-5 were investigated by immunohistochemistry, Western-blotting and real-time PCR respectively. Results  After exposure to acute hypoxia for 5 days, compared with NC group, the water content of brain in SH group increased obviously (PPPPPConclusion  Acute hypoxia exposure may lead to a remarkable decline of the expressions of rat's brain Occludin protein and the Occludin, Zo-1 and Claudin-5 mRNA, and an obvious increase of BBB permeability. Sodium aescinate can up-regulate the expression level of these molecules and decrease BBB permeability, thus playing a profitable role of anti-leakage and BBB protection.

Modulation of ocular surface glycocalyx barrier function by a galectin-3 N-terminal deletion mutant and membrane-anchored synthetic glycopolymers.

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Jerome Mauris

Full Text Available BACKGROUND: Interaction of transmembrane mucins with the multivalent carbohydrate-binding protein galectin-3 is critical to maintaining the integrity of the ocular surface epithelial glycocalyx. This study aimed to determine whether disruption of galectin-3 multimerization and insertion of synthetic glycopolymers in the plasma membrane could be used to modulate glycocalyx barrier function in corneal epithelial cells. METHODOLOGY/PRINCIPAL FINDINGS: Abrogation of galectin-3 biosynthesis in multilayered cultures of human corneal epithelial cells using siRNA, and in galectin-3 null mice, resulted in significant loss of corneal barrier function, as indicated by increased permeability to the rose bengal diagnostic dye. Addition of β-lactose, a competitive carbohydrate inhibitor of galectin-3 binding activity, to the cell culture system, transiently disrupted barrier function. In these experiments, treatment with a dominant negative inhibitor of galectin-3 polymerization lacking the N-terminal domain, but not full-length galectin-3, prevented the recovery of barrier function to basal levels. As determined by fluorescence microscopy, both cellobiose- and lactose-containing glycopolymers incorporated into apical membranes of corneal epithelial cells, independently of the chain length distribution of the densely glycosylated, polymeric backbones. Membrane incorporation of cellobiose glycopolymers impaired barrier function in corneal epithelial cells, contrary to their lactose-containing counterparts, which bound to galectin-3 in pull-down assays. CONCLUSIONS/SIGNIFICANCE: These results indicate that galectin-3 multimerization and surface recognition of lactosyl residues is required to maintain glycocalyx barrier function at the ocular surface. Transient modification of galectin-3 binding could be therapeutically used to enhance the efficiency of topical drug delivery.

Implementation of a permeable reactive barrier for treatment of groundwater impacted by strontium-90

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Przepiora, A.; Bodine, D.; Dollar, P.; Smith, P.

2014-01-01

A funnel and gate permeable reactive barrier (PRB) system was constructed to treat strontium-90 (Sr- 90) in groundwater migrating from a legacy waste disposal area into an adjacent wetland. The PRB system was designed to contain and direct the Sr-90 impacted groundwater into treatment 'gates' containing zeolite using a low permeability 'funnel' sections constructed with soil-bentonite slurry. The constructed PRB met all dimension and permeability specifications. Initial performance monitoring results indicate that the PRB captured the Sr-90 impacted groundwater plume and the beta radiation values in groundwater emerging from the treatment gates ranged from 35 to 86 Becquerel's per litre (Bq/L), equivalent to a reduction by 88% to 99% from the influent values. Those initial performance results were influenced by residual impacts present in the aquifer material prior to PRB installation. It is anticipated that the clean-up target of 5 Bq/L will be achieved with time as treated groundwater emerging from the PRB flushes through the downgradient aquifer zone. (author)

Effects of ethanol and acetaldehyde on tight junction integrity: in vitro study in a three dimensional intestinal epithelial cell culture model.

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Elhaseen Elamin

Full Text Available BACKGROUND: Intestinal barrier dysfunction and translocation of endotoxins are involved in the pathogenesis of alcoholic liver disease. Exposure to ethanol and its metabolite, acetaldehyde at relatively high concentrations have been shown to disrupt intestinal epithelial tight junctions in the conventional two dimensional cell culture models. The present study investigated quantitatively and qualitatively the effects of ethanol at concentrations detected in the blood after moderate ethanol consumption, of its metabolite acetaldehyde and of the combination of both compounds on intestinal barrier function in a three-dimensional cell culture model. METHODS AND FINDINGS: Caco-2 cells were grown in a basement membrane matrix (Matrigel™ to induce spheroid formation and were then exposed to the compounds at the basolateral side. Morphological differentiation of the spheroids was assessed by immunocytochemistry and transmission electron microscopy. The barrier function was assessed by the flux of FITC-labeled dextran from the basal side into the spheroids' luminal compartment using confocal microscopy. Caco-2 cells grown on Matrigel assembled into fully differentiated and polarized spheroids with a central lumen, closely resembling enterocytes in vivo and provide an excellent model to study epithelial barrier functionality. Exposure to ethanol (10-40 mM or acetaldehyde (25-200 µM for 3 h, dose-dependently and additively increased the paracellular permeability and induced redistribution of ZO-1 and occludin without affecting cell viability or tight junction-encoding gene expression. Furthermore, ethanol and acetaldehyde induced lysine residue and microtubules hyperacetylation. CONCLUSIONS: These results indicate that ethanol at concentrations found in the blood after moderate drinking and acetaldehyde, alone and in combination, can increase the intestinal epithelial permeability. The data also point to the involvement of protein hyperacetylation in

In vitro blood-brain barrier permeability predictions for GABAA receptor modulating piperine analogs.

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Eigenmann, Daniela Elisabeth; Dürig, Carmen; Jähne, Evelyn Andrea; Smieško, Martin; Culot, Maxime; Gosselet, Fabien; Cecchelli, Romeo; Helms, Hans Christian Cederberg; Brodin, Birger; Wimmer, Laurin; Mihovilovic, Marko D; Hamburger, Matthias; Oufir, Mouhssin

2016-06-01

The alkaloid piperine from black pepper (Piper nigrum L.) and several synthetic piperine analogs were recently identified as positive allosteric modulators of γ-aminobutyric acid type A (GABAA) receptors. In order to reach their target sites of action, these compounds need to enter the brain by crossing the blood-brain barrier (BBB). We here evaluated piperine and five selected analogs (SCT-66, SCT-64, SCT-29, LAU397, and LAU399) regarding their BBB permeability. Data were obtained in three in vitro BBB models, namely a recently established human model with immortalized hBMEC cells, a human brain-like endothelial cells (BLEC) model, and a primary animal (bovine endothelial/rat astrocytes co-culture) model. For each compound, quantitative UHPLC-MS/MS methods in the range of 5.00-500ng/mL in the corresponding matrix were developed, and permeability coefficients in the three BBB models were determined. In vitro predictions from the two human BBB models were in good agreement, while permeability data from the animal model differed to some extent, possibly due to protein binding of the screened compounds. In all three BBB models, piperine and SCT-64 displayed the highest BBB permeation potential. This was corroborated by data from in silico prediction. For the other piperine analogs (SCT-66, SCT-29, LAU397, and LAU399), BBB permeability was low to moderate in the two human BBB models, and moderate to high in the animal BBB model. Efflux ratios (ER) calculated from bidirectional permeability experiments indicated that the compounds were likely not substrates of active efflux transporters. Copyright © 2016 Elsevier B.V. All rights reserved.

Eosinophils express muscarinic receptors and corticotropin-releasing factor to disrupt the mucosal barrier in ulcerative colitis.

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Wallon, Conny; Persborn, Mats; Jönsson, Maria; Wang, Arthur; Phan, Van; Lampinen, Maria; Vicario, Maria; Santos, Javier; Sherman, Philip M; Carlson, Marie; Ericson, Ann-Charlott; McKay, Derek M; Söderholm, Johan D

2011-05-01

Altered intestinal barrier function has been implicated in the pathophysiology of ulcerative colitis (UC) in genetic, functional, and epidemiological studies. Mast cells and corticotropin-releasing factor (CRF) regulate the mucosal barrier in human colon. Because eosinophils are often increased in colon tissues of patients with UC, we assessed interactions among mast cells, CRF, and eosinophils in the mucosal barrier of these patients. Transmucosal fluxes of protein antigens (horseradish peroxidase) and paracellular markers ((51)Cr-EDTA, fluorescein isothiocyanate-dextran 4000) were studied in noninflamed, colonic mucosal biopsy samples collected from 26 patients with UC and 53 healthy volunteers (controls); samples were mounted in Ussing chambers. We also performed fluorescence and electron microscopy of human tissue samples, assessed isolated eosinophils, and performed mechanistic studies using in vitro cocultured eosinophils (15HL-60), mast cells (HMC-1), and a colonic epithelial cell line (T84). Colon tissues from patients with UC had significant increases in permeability to protein antigens compared with controls. Permeability was blocked by atropine (a muscarinic receptor antagonist), α-helical CRF(9-41) (a CRF receptor antagonist), and lodoxamide (a mast-cell stabilizer). Eosinophils were increased in number in UC tissues (compared with controls), expressed the most M2 and M3 muscarinic receptors of any mucosal cell type, and had immunoreactivity to CRF. In coculture studies, carbachol activation of eosinophils caused production of CRF and activation of mast cells, which increased permeability of T84 epithelial cells to macromolecules. We identified a neuroimmune intercellular circuit (from cholinergic nerves, via eosinophils to mast cells) that mediates colonic mucosal barrier dysfunction in patients with UC. This circuit might exacerbate mucosal inflammation. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

Long-Term Groundwater Monitoring Optimization, Clare Water Supply Superfund Site, Permeable Reactive Barrier and Soil Remedy Areas, Clare, Michigan

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This report contains a review of the long-term groundwater monitoring network for the Permeable Reactive Barrier (PRB) and Soil Remedy Areas at the Clare Water Supply Superfund Site in Clare, Michigan.

Pulmonary epithelial permeability in normal subjects and patients with idiopathic interstitial pneumonia

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Anazawa, Yoshiki; Isawa, Toyoharu; Teshima, Takeo; Miki, Makoto; Motomiya, Masakichi

1991-01-01

99m Tc-DTPA is a low molecular weight substance, which is believed to pass through the pulmonary epithelium when it is inhaled as an aerosol. We performed 99m Tc-DTPA inhalation studies in 10 nonsmoking normal subjects and 10 patients with biopsy proven idiopathic interstitial pneumonia prior to therapy. 99m Tc-DTPA aerosol was inhaled for 3 min with the subject in the supine position and radioactivity was measured anteriorly with a gamma camera and recorded on computer. Measurements were performed for 3 min with the subject inhaling aerosol and for the subsequent 30 min with the subject in the same position. Time activity curves from the five regions of interest (ROIs) including the entire left lung, the entire right lung, and the upper, middle and lower third of the right lung were separately fitted to a single exponential function for the initial 7 min following cessation of inhalation, and the respective clearance half life (t1/2) in min was calculated. Lung function data, arterial blood gas tensions and blood chemistry were also obtained for comparison with the t1/2 values. The t1/2 values were significantly smaller in all ROIs in patients with idiopathic interstitial pneumonia than in normal subjects, indicating an increased pulmonary epithelial permeability in these patients. There was no relationship between t1/2 and %DL co , %DL co /V A , PaO 2 , or LDH. Although the true pathophysiologic significance of t1/2 measured using 99m Tc-DTPA aerosol is still not known, we consider that this measurement may be an important indicator of nonrespiratory lung function, in particular the degree of alveolar epithelial damage. (author)

Bexarotene reduces blood-brain barrier permeability in cerebral ischemia-reperfusion injured rats.

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Lu Xu

Full Text Available Matrix metalloproteinase-9 (MMP-9 over-expression disrupts the blood-brain barrier (BBB in the ischemic brain. The retinoid X receptor agonist bexarotene suppresses MMP-9 expression in endothelial cells and displays neuroprotective effects. Therefore, we hypothesized that bexarotene may have a beneficial effect on I/R-induced BBB dysfunction.A total of 180 rats were randomized into three groups (n = 60 each: (i a sham-operation group, (ii a cerebral ischemia-reperfusion (I/R group, and (iii an I/R+bexarotene group. Brain water content was measured by the dry wet weight method. BBB permeability was analyzed by Evans Blue staining and the magnetic resonance imaging contrast agent Omniscan. MMP-9 mRNA expression, protein expression, and activity were assessed by reverse transcription polymerase chain reaction, Western blotting, and gelatin zymography, respectively. Apolipoprotein E (apoE, claudin-5, and occludin expression were analyzed by Western blotting.After 24 h, 48 h, and 72 h post-I/R, several effects were observed with bexarotene administration: (i brain water content and BBB permeability were significantly reduced; (ii MMP-9 mRNA and protein expression as well as activity were significantly decreased; (iii claudin-5 and occludin expression were significantly increased; and (iv apoE expression was significantly increased.Bexarotene decreases BBB permeability in rats with cerebral I/R injury. This effect may be due in part to bexarotene's upregulation of apoE expression, which has been previously shown to reduce BBB permeability through suppressing MMP-9-mediated degradation of the tight junction proteins claudin-5 and occludin. This work offers insight to aid future development of therapeutic agents for cerebral I/R injury in human patients.

Zonulin, a regulator of epithelial and endothelial barrier functions, and its involvement in chronic inflammatory diseases.

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Sturgeon, Craig; Fasano, Alessio

2016-01-01

Beside digesting nutrients and absorbing solutes and electrolytes, the intestinal epithelium with its barrier function is in charge of a tightly controlled antigen trafficking from the intestinal lumen to the submucosa. This trafficking dictates the delicate balance between tolerance and immune response causing inflammation. Loss of barrier function secondary to upregulation of zonulin, the only known physiological modulator of intercellular tight junctions, leads to uncontrolled influx of dietary and microbial antigens. Additional insights on zonulin mechanism of action and the recent appreciation of the role that altered intestinal permeability can play in the development and progression of chronic inflammatory disorders has increased interest of both basic scientists and clinicians on the potential role of zonulin in the pathogenesis of these diseases. This review focuses on the recent research implicating zonulin as a master regulator of intestinal permeability linked to the development of several chronic inflammatory disorders.

Comparison of a Rat Primary Cell-Based Blood-Brain Barrier Model With Epithelial and Brain Endothelial Cell Lines: Gene Expression and Drug Transport

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Szilvia Veszelka

2018-05-01

Full Text Available Cell culture-based blood-brain barrier (BBB models are useful tools for screening of CNS drug candidates. Cell sources for BBB models include primary brain endothelial cells or immortalized brain endothelial cell lines. Despite their well-known differences, epithelial cell lines are also used as surrogate models for testing neuropharmaceuticals. The aim of the present study was to compare the expression of selected BBB related genes including tight junction proteins, solute carriers (SLC, ABC transporters, metabolic enzymes and to describe the paracellular properties of nine different culture models. To establish a primary BBB model rat brain capillary endothelial cells were co-cultured with rat pericytes and astrocytes (EPA. As other BBB and surrogate models four brain endothelial cells lines, rat GP8 and RBE4 cells, and human hCMEC/D3 cells with or without lithium treatment (D3 and D3L, and four epithelial cell lines, native human intestinal Caco-2 and high P-glycoprotein expressing vinblastine-selected VB-Caco-2 cells, native MDCK and MDR1 transfected MDCK canine kidney cells were used. To test transporter functionality, the permeability of 12 molecules, glucopyranose, valproate, baclofen, gabapentin, probenecid, salicylate, rosuvastatin, pravastatin, atorvastatin, tacrine, donepezil, was also measured in the EPA and epithelial models. Among the junctional protein genes, the expression level of occludin was high in all models except the GP8 and RBE4 cells, and each model expressed a unique claudin pattern. Major BBB efflux (P-glycoprotein or ABCB1 and influx transporters (GLUT-1, LAT-1 were present in all models at mRNA levels. The transcript of BCRP (ABCG2 was not expressed in MDCK, GP8 and RBE4 cells. The absence of gene expression of important BBB efflux and influx transporters BCRP, MRP6, -9, MCT6, -8, PHT2, OATPs in one or both types of epithelial models suggests that Caco-2 or MDCK models are not suitable to test drug candidates which

Dual Function of Novel Pollen Coat (Surface) Proteins: IgE-binding Capacity and Proteolytic Activity Disrupting the Airway Epithelial Barrier

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Bashir, Mohamed Elfatih H.; Ward, Jason M.; Cummings, Matthew; Karrar, Eltayeb E.; Root, Michael; Mohamed, Abu Bekr A.; Naclerio, Robert M.; Preuss, Daphne

2013-01-01

Background The pollen coat is the first structure of the pollen to encounter the mucosal immune system upon inhalation. Prior characterizations of pollen allergens have focused on water-soluble, cytoplasmic proteins, but have overlooked much of the extracellular pollen coat. Due to washing with organic solvents when prepared, these pollen coat proteins are typically absent from commercial standardized allergenic extracts (i.e., “de-fatted”), and, as a result, their involvement in allergy has not been explored. Methodology/Principal Findings Using a unique approach to search for pollen allergenic proteins residing in the pollen coat, we employed transmission electron microscopy (TEM) to assess the impact of organic solvents on the structural integrity of the pollen coat. TEM results indicated that de-fatting of Cynodon dactylon (Bermuda grass) pollen (BGP) by use of organic solvents altered the structural integrity of the pollen coat. The novel IgE-binding proteins of the BGP coat include a cysteine protease (CP) and endoxylanase (EXY). The full-length cDNA that encodes the novel IgE-reactive CP was cloned from floral RNA. The EXY and CP were purified to homogeneity and tested for IgE reactivity. The CP from the BGP coat increased the permeability of human airway epithelial cells, caused a clear concentration-dependent detachment of cells, and damaged their barrier integrity. Conclusions/Significance Using an immunoproteomics approach, novel allergenic proteins of the BGP coat were identified. These proteins represent a class of novel dual-function proteins residing on the coat of the pollen grain that have IgE-binding capacity and proteolytic activity, which disrupts the integrity of the airway epithelial barrier. The identification of pollen coat allergens might explain the IgE-negative response to available skin-prick-testing proteins in patients who have positive symptoms. Further study of the role of these pollen coat proteins in allergic responses is

Dual function of novel pollen coat (surface proteins: IgE-binding capacity and proteolytic activity disrupting the airway epithelial barrier.

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Mohamed Elfatih H Bashir

Full Text Available BACKGROUND: The pollen coat is the first structure of the pollen to encounter the mucosal immune system upon inhalation. Prior characterizations of pollen allergens have focused on water-soluble, cytoplasmic proteins, but have overlooked much of the extracellular pollen coat. Due to washing with organic solvents when prepared, these pollen coat proteins are typically absent from commercial standardized allergenic extracts (i.e., "de-fatted", and, as a result, their involvement in allergy has not been explored. METHODOLOGY/PRINCIPAL FINDINGS: Using a unique approach to search for pollen allergenic proteins residing in the pollen coat, we employed transmission electron microscopy (TEM to assess the impact of organic solvents on the structural integrity of the pollen coat. TEM results indicated that de-fatting of Cynodon dactylon (Bermuda grass pollen (BGP by use of organic solvents altered the structural integrity of the pollen coat. The novel IgE-binding proteins of the BGP coat include a cysteine protease (CP and endoxylanase (EXY. The full-length cDNA that encodes the novel IgE-reactive CP was cloned from floral RNA. The EXY and CP were purified to homogeneity and tested for IgE reactivity. The CP from the BGP coat increased the permeability of human airway epithelial cells, caused a clear concentration-dependent detachment of cells, and damaged their barrier integrity. CONCLUSIONS/SIGNIFICANCE: Using an immunoproteomics approach, novel allergenic proteins of the BGP coat were identified. These proteins represent a class of novel dual-function proteins residing on the coat of the pollen grain that have IgE-binding capacity and proteolytic activity, which disrupts the integrity of the airway epithelial barrier. The identification of pollen coat allergens might explain the IgE-negative response to available skin-prick-testing proteins in patients who have positive symptoms. Further study of the role of these pollen coat proteins in allergic

Salmosan, a β-galactomannan-rich product, in combination with Lactobacillus plantarum contributes to restore intestinal epithelial barrier function by modulation of cytokine production.

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Brufau, M Teresa; Campo-Sabariz, Joan; Carné, Sergi; Ferrer, Ruth; Martín-Venegas, Raquel

2017-03-01

Mannan-oligosaccharides (MOSs) are mannose-rich substrates with several intestinal health-promoting properties. The aim of this study was to investigate the potential capacity of Salmosan (S-βGM), a β-galactomannan-rich MOS product, to restore epithelial barrier function independently from its capacity to reduce bacterial invasion. In addition, the combination of S-βGM with the proven probiotic Lactobacillus plantarum (LP) was also tested. Paracellular permeability was assessed by transepithelial electrical resistance (TER) in co-cultures of Caco-2 cells and macrophages (differentiated from THP-1 cells) stimulated with LPS of Salmonella Enteritidis and in Caco-2 cell cultures stimulated with TNF-α in the absence or presence of 500 μg/ml S-βGM, LP (MOI 10) or a combination of both. In both culture models, TER was significantly reduced up to 25% by LPS or TNF-α stimulation, and the addition of S-βGM or LP alone did not modify TER, whereas the combination of both restored TER to values of nonstimulated cells. Under LPS stimulation, TNF-α production was significantly increased by 10-fold, whereas IL-10 and IL-6 levels were not modified. The combination of S-βGM and LP reduced TNF-α production to nonstimulated cell values and significantly increased IL-10 and IL-6 levels (5- and 7.5-fold, respectively). Moreover, S-βGM has the capacity to induce an increase of fivefold in LP growth. In conclusion, we have demonstrated that S-βGM in combination with LP protects epithelial barrier function by modulation of cytokine secretion, thus giving an additional value to this MOS as a potential symbiotic. Copyright © 2016 Elsevier Inc. All rights reserved.

Tight junction proteins contribute to barrier properties in human pleura.

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Markov, Alexander G; Voronkova, Maria A; Volgin, George N; Yablonsky, Piotr K; Fromm, Michael; Amasheh, Salah

2011-03-15

The permeability of pleural mesothelium helps to control the volume and composition of the liquid lubricating pleural surfaces. Information on pleural barrier function in health and disease, however, is scarce. Tissue specimens of human pleura were mounted in Ussing chambers for measurement of transmesothelial resistance. Expression of tight junction (TJ) proteins was studied by Western blots and immune fluorescence confocal microscopy. Both visceral and parietal pleura showed barrier properties represented by transmesothelial resistance. Occludin, claudin-1, -3, -5, and -7, were detected in visceral pleura. In parietal pleura, the same TJ proteins were detected, except claudin-7. In tissues from patients with pleural inflammation these tightening claudins were decreased and in visceral pleura claudin-2, a paracellular channel former, became apparent. We report that barrier function in human pleura coincides with expression of claudins known to be key determinants of epithelial barrier properties. In inflamed tissue, claudin expression indicates a reduced barrier function. Copyright © 2010 Elsevier B.V. All rights reserved.

Effect of Exercise Intensity on Neurotrophic Factors and Blood-Brain Barrier Permeability Induced by Oxidative-Nitrosative Stress in Male College Students.

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Roh, Hee-Tae; Cho, Su-Youn; Yoon, Hyung-Gi; So, Wi-Young

2017-06-01

We investigated the effects of aerobic exercise intensity on oxidative-nitrosative stress, neurotrophic factor expression, and blood-brain barrier (BBB) permeability. Fifteen healthy men performed treadmill running under low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) conditions. Blood samples were collected immediately before exercise (IBE), immediately after exercise (IAE), and 60 min after exercise (60MAE) to examine oxidative-nitrosative stress (reactive oxygen species [ROS]; nitric oxide [NO]), neurotrophic factors (brain-derived neurotrophic factor [BDNF]; nerve growth factor [NGF]), and blood-brain barrier (BBB) permeability (S-100β; neuron-specific enolase). ROS concentration significantly increased IAE and following HI (4.9 ± 1.7 mM) compared with that after LI (2.8 ± 1.4 mM) exercise (p exercise (p exercise (p exercise (p exercise (p .05). Moderate- and/or high-intensity exercise may induce higher oxidative-nitrosative stress than may low-intensity exercise, which can increase peripheral neurotrophic factor levels by increasing BBB permeability.

Inhibition of Epithelial TNF-α Receptors by Purified Fruit Bromelain Ameliorates Intestinal Inflammation and Barrier Dysfunction in Colitis.

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Zhou, Zijuan; Wang, Liang; Feng, Panpan; Yin, Lianhong; Wang, Chen; Zhi, Shengxu; Dong, Jianyi; Wang, Jingyu; Lin, Yuan; Chen, Dapeng; Xiong, Yongjian; Peng, Jinyong

2017-01-01

Activation of the TNF-α receptor (TNFR) leads to an inflammatory response, and anti-TNF therapy has been administered to reduce inflammation symptoms and heal mucosal ulcers in inflammatory bowel disease (IBD). Bromelain, a complex natural mixture of proteolytic enzymes, has been shown to exert anti-inflammatory effects. This study aimed to investigate the effect of purified fruit bromelain (PFB)-induced inhibition of epithelial TNFR in a rat colitis model. Colitis was established by intracolonic administration of 2, 4, 6-trinitrobenzene sulfonic acid. Expression of TNFR1 and TNFR2 was measured by quantitative RT-PCR and western blotting. The effect of PFB on colitis was evaluated by examining the inflammatory response and intestinal epithelial barrier function. Our results showed that both TNFR1 and TNFR2 expression were significantly increased in a colitis model, and the increase was significantly reversed by PFB. Colitis symptoms, including infiltration of inflammatory cells, cytokine profiles, epithelial cell apoptosis, and epithelial tight junction barrier dysfunction were significantly ameliorated by PFB. Compared with fruit bromelain and stem bromelain complex, the inhibition of TNFR2 induced by PFB was stronger than that exhibited on TNFR1. These results indicate that PFB showed a stronger selective inhibitory effect on TNFR2 than TNFR1. In other words, purification of fruit bromelain increases its selectivity on TNFR2 inhibition. High expression of epithelial TNFRs in colitis was significantly counteracted by PFB, and PFB-induced TNFR inhibition ameliorated colitis symptoms. These results supply novel insights into potential IBD treatment by PFB.

Prediction of Central Nervous System Side Effects Through Drug Permeability to Blood-Brain Barrier and Recommendation Algorithm.

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Fan, Jun; Yang, Jing; Jiang, Zhenran

2018-04-01

Drug side effects are one of the public health concerns. Using powerful machine-learning methods to predict potential side effects before the drugs reach the clinical stages is of great importance to reduce time consumption and protect the security of patients. Recently, researchers have proved that the central nervous system (CNS) side effects of a drug are closely related to its permeability to the blood-brain barrier (BBB). Inspired by this, we proposed an extended neighborhood-based recommendation method to predict CNS side effects using drug permeability to the BBB and other known features of drug. To the best of our knowledge, this is the first attempt to predict CNS side effects considering drug permeability to the BBB. Computational experiments demonstrated that drug permeability to the BBB is an important factor in CNS side effects prediction. Moreover, we built an ensemble recommendation model and obtained higher AUC score (area under the receiver operating characteristic curve) and AUPR score (area under the precision-recall curve) on the data set of CNS side effects by integrating various features of drug.

Inflammasome Inhibition Suppresses Alveolar Cell Permeability Through Retention of Neuregulin-1 (NRG-1

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Rajanbabu Venugopal

2015-07-01

Full Text Available Background: Neuregulin (NRG-1-human epidermal receptor (HER-2 signaling pathway is a key regulator of IL-1β-mediated pulmonary inflammation and epithelial permeability. The inflammasome is a newly discovered molecular platform required for caspase-1 activation and maturation of IL-1β. However, the role of the inflammasome in NRG-1-HER2 signaling-mediated alveolar cell permeability is unknown. Methods: The inflammasome was activated or inhibited in THP-1 cells; supernatants from these cells were added to A549 cells and human small airway epithelial cells (HSAEC. The protein expression of NRG-1 and phospho-HER2 (pHER2 were measured by Western blot analysis and epithelial permeability was measured using Lucifer yellow dye. Results: Results reveal that alveolar permeability in A549 cells and HSAEC is increased when treated with supernatants of inflammasome-activated THP-1 cells. Alveolar permeability is significantly suppressed when treated with supernatant of inflammasome-inhibited THP-1 cells. Inflammasome-mediated permeability is decreased when A549 cells and HSAEC are pretreated with IL-1β receptor antagonist (IL-1βRA. In addition, HER2 kinase inhibitor AG825 or NRG-1 inhibitor TAPI inhibits inflammasome-mediated permeability in A549 cells and HSAEC demonstrating critical roles of IL-1β, NRG-1, and HER2 in inflammasome-mediated alveolar permeability. Conclusion: These findings suggest that inflammasome-induced alveolar cell permeability is mediated by NRG-1/HER2 signaling through IL-1β regulation.

The long noncoding RNA TUG1 regulates blood-tumor barrier permeability by targeting miR-144.

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Cai, Heng; Xue, Yixue; Wang, Ping; Wang, Zhenhua; Li, Zhen; Hu, Yi; Li, Zhiqing; Shang, Xiuli; Liu, Yunhui

2015-08-14

Blood-tumor barrier (BTB) limits the delivery of chemotherapeutic agent to brain tumor tissues. Long non-coding RNAs (lncRNAs) have been shown to play critical regulatory roles in various biologic processes of tumors. However, the role of lncRNAs in BTB permeability is unclear. LncRNA TUG1 (taurine upregulated gene 1) was highly expressed in glioma vascular endothelial cells from glioma tissues. It also upregulated in glioma co-cultured endothelial cells (GEC) from BTB model in vitro. Knockdown of TUG1 increased BTB permeability, and meanwhile down-regulated the expression of the tight junction proteins ZO-1, occludin, and claudin-5. Both bioinformatics and luciferase reporter assays demonstrated that TUG1 influenced BTB permeability via binding to miR-144. Furthermore, Knockdown of TUG1 also down-regulated Heat shock transcription factor 2 (HSF2), a transcription factor of the heat shock transcription factor family, which was defined as a direct and functional downstream target of miR-144. HSF2 up-regulated the promoter activities and interacted with the promoters of ZO-1, occludin, and claudin-5 in GECs. In conclusion, our results indicate that knockdown of TUG1 increased BTB permeability via binding to miR-144 and then reducing EC tight junction protein expression by targeting HSF2. Thus, TUG1 may represent a useful future therapeutic target for enhancing BTB permeability.

Identification of two immortalized cell lines, ECV304 and bEnd3, for in vitro permeability studies of blood-brain barrier.

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Shu Yang

Full Text Available To identify suitable cell lines for a mimetic system of in vivo blood-brain barrier (BBB for drug permeability assessment, we characterized two immortalized cell lines, ECV304 and bEnd3 in the respect of the tightness, tight junction proteins, P-glycoprotein (P-gp function and discriminative brain penetration. The ECV304 monoculture achieved higher transendothelial electrical resistance (TEER and lower permeability to Lucifer yellow than bEnd3. However, co-culture with rat glioma C6 cells impaired the integrity of ECV304 and bEnd3 cell layers perhaps due to the heterogeneity among C6 cells in inducing BBB characteristics. The immunostaining of ZO-1 delivered distinct bands along cell borders on both cell lines while those of occludin and claudin-5 were diffused and weak. P-gp functionality was only proved in bEnd3 by Rhodamine 123 (R123 uptake assay. A permeability test of reference compounds displayed a similar rank order (digoxin < R123 < quinidine, verapamil < propranolol in ECV304 and bEnd3 cells. In comparison with bEnd3, ECV304 developed tighter barrier for the passage of reference compounds and higher discrimination between transcellular and paracellular transport. However, the monoculture models of ECV304 and bEnd3 fail to achieve the sufficient tightness of in vitro BBB permeability models with high TEER and evident immunostaining of tight junction proteins. Further strategies to enhance the paracellular tightness of both cell lines to mimic in vivo BBB tight barrier deserve to be conducted.

Enhancement and inhibition effects on the corneal permeability of timolol maleate: Polymers, cyclodextrins and chelating agents.

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Rodríguez, Isabel; Vázquez, José Antonio; Pastrana, Lorenzo; Khutoryanskiy, Vitaliy V

2017-08-30

This study investigates how both bioadhesive polymers (chitosan, hyaluronic acid and alginate) and permeability enhancers (ethylene glycol- bis(2-aminoethylether)- N, N, N', N'- tetraacetic acid (EGTA) and hydroxypropyl-ß-cyclodextrin) influence the permeability of the anti-glaucoma drug timolol maleate through ex vivo bovine corneas. Our results showed that only the permeability enhancers alone were able to increase drug permeability, whereas the polymers significantly reduced drug permeation, and however, they increased the pre-corneal residence of timolol. Ternary systems (polymer-enhancer-drug) showed a reduced drug permeability compared to the polymers alone. Fluorescence microscopy analysis of the epithelium surface confirmed there was no evidence of epithelial disruption caused by these formulations, suggesting that polymer-enhancer interactions reduce drug solubilization and counteract the disruptive effect of the permeability enhancers on the surface of the cornea. Further mucoadhesive tests, revealed a stable interaction of chitosan and hyaluronic acid with the epithelium, while alginate showed poor mucoadhesive properties. The differences in mucoadhesion correlated with the permeability of timolol maleate observed, i.e. formulations containing mucoadhesive polymers showed lower drug permeabilities. The results of the present study indicate polymers acting as an additional barrier towards drug permeability which is even more evident in the presence of permeability enhancers like EGTA and hydroxypropyl-ß-cyclodextrin. Then, this study highlights the need to adequately select additives intended for ocular applications since interactions between them can have opposite results to what expected in terms of drug permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

Protective Effects of Bifidobacterium on Intestinal Barrier Function in LPS-Induced Enterocyte Barrier Injury of Caco-2 Monolayers and in a Rat NEC Model.

Directory of Open Access Journals (Sweden)

Xiang Ling

Full Text Available Zonulin protein is a newly discovered modulator which modulates the permeability of the intestinal epithelial barrier by disassembling intercellular tight junctions (TJ. Disruption of TJ is associated with neonatal necrotizing enterocolitis (NEC. It has been shown bifidobacterium could protect the intestinal barrier function and prophylactical administration of bifidobacterium has beneficial effects in NEC patients and animals. However, it is still unknown whether the zonulin is involved in the gut barrier dysfunction of NEC, and the protective mechanisms of bifidobacterium on intestinal barrier function are also not well understood. The present study aims to investigate the effects of bifidobacterium on intestinal barrier function, zonulin regulation, and TJ integrity both in LPS-induced enterocyte barrier injury of Caco-2 monolayers and in a rat NEC model. Our results showed bifidobacterium markedly attenuated the decrease in transepithelial electrical resistance and the increase in paracellular permeability in the Caco-2 monolayers treated with LPS (P < 0.01. Compared with the LPS group, bifidobacterium significantly decreased the production of IL-6 and TNF-α (P < 0.01 and suppressed zonulin release (P < 0.05. In addition, bifidobacterium pretreatment up-regulated occludin, claudin-3 and ZO-1 expression (P < 0.01 and also preserved these proteins localization at TJ compared with the LPS group. In the in vivo study, bifidobacterium decreased the incidence of NEC from 88 to 47% (P < 0.05 and reduced the severity in the NEC model. Increased levels of IL-6 and TNF-α in the ileum of NEC rats were normalized in bifidobacterium treated rats (P < 0.05. Moreover, administration of bifidobacterium attenuated the increase in intestinal permeability (P < 0.01, decreased the levels of serum zonulin (P < 0.05, normalized the expression and localization of TJ proteins in the ileum compared with animals with NEC. We concluded that bifidobacterium may

The bile acids, deoxycholic acid and ursodeoxycholic acid, regulate colonic epithelial wound healing.

Science.gov (United States)

Mroz, Magdalena S; Lajczak, Natalia K; Goggins, Bridie J; Keely, Simon; Keely, Stephen J

2018-03-01

The intestinal epithelium constitutes an innate barrier which, upon injury, undergoes self-repair processes known as restitution. Although bile acids are known as important regulators of epithelial function in health and disease, their effects on wound healing processes are not yet clear. Here we set out to investigate the effects of the colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on epithelial restitution. Wound healing in T 84 cell monolayers grown on transparent, permeable supports was assessed over 48 h with or without bile acids. Cell migration was measured in Boyden chambers. mRNA and protein expression were measured by RT-PCR and Western blotting. DCA (50-150 µM) significantly inhibited wound closure in cultured epithelial monolayers and attenuated cell migration in Boyden chamber assays. DCA also induced nuclear accumulation of the farnesoid X receptor (FXR), whereas an FXR agonist, GW4064 (10 µM), inhibited wound closure. Both DCA and GW4064 attenuated the expression of CFTR Cl - channels, whereas inhibition of CFTR activity with either CFTR- inh -172 (10 µM) or GlyH-101 (25 µM) also prevented wound healing. Promoter/reporter assays revealed that FXR-induced downregulation of CFTR is mediated at the transcriptional level. In contrast, UDCA (50-150 µM) enhanced wound healing in vitro and prevented the effects of DCA. Finally, DCA inhibited and UDCA promoted mucosal healing in an in vivo mouse model. In conclusion, these studies suggest bile acids are important regulators of epithelial wound healing and are therefore good targets for development of new drugs to modulate intestinal barrier function in disease treatment. NEW & NOTEWORTHY The secondary bile acid, deoxycholic acid, inhibits colonic epithelial wound healing, an effect which appears to be mediated by activation of the nuclear bile acid receptor, FXR, with subsequent downregulation of CFTR expression and activity. In contrast, ursodeoxycholic acid promotes

Confirmation tests of construction method and initial performance quality for low permeable engineered barrier in side part of radioactive waste disposal facilities

International Nuclear Information System (INIS)

Yamada, Atsuo; Chijimatsu, Masakazu; Akiyama, Yoshihiro; Komine, Hideo; Iizuka, Atsushi

2016-01-01

As for the low permeable layer, important functions are expected as an engineered barrier of radioactive waste disposal for low-level waste with comparatively high radiation levels. On examining the construction methods of this low permeable layer, it is important to confirm the possibility of the construction in the conditions similar to the actual constructed conditions with a true scale size. Therefore, the construction examination for the side part of the low permeable layer by bentonite and the performance check test of the low permeable layer were carried out. The result of the construction examination showed that the possibility of the construction were confirmed, and the result of performance check test showed that it was possible to ensure the required performance of the low permeable layer, such as hydraulic conductivity. (author)

Blood-brain barrier permeability and brain uptake mechanism of kainic Acid and dihydrokainic Acid

DEFF Research Database (Denmark)

Gynther, Mikko; Petsalo, Aleksanteri; Hansen, Steen Honoré

2015-01-01

tools in various in vivo central nervous system disease models in rodents, as well as being templates in the design of novel ligands affecting the glutamatergic system. Both molecules are highly polar but yet capable of crossing the blood-brain barrier (BBB). We used an in situ rat brain perfusion...... technique to determine the brain uptake mechanism and permeability across the BBB. To determine KA and DHK concentrations in the rat brain, simple and rapid sample preparation and liquid chromatography mass spectrometer methods were developed. According to our results the BBB permeability of KA and DHK...... is low, 0.25 × 10(-6) and 0.28 × 10(-6) cm/s for KA and DHK, respectively. In addition, the brain uptake is mediated by passive diffusion, and not by active transport. Furthermore, the non-specific plasma and brain protein binding of KA and DHK was determined to be low, which means that the unbound drug...

MARCKS-related protein regulates cytoskeletal organization at cell-cell and cell-substrate contacts in epithelial cells.

Science.gov (United States)

Van Itallie, Christina M; Tietgens, Amber Jean; Aponte, Angel; Gucek, Marjan; Cartagena-Rivera, Alexander X; Chadwick, Richard S; Anderson, James M

2018-02-02

Treatment of epithelial cells with interferon-γ and TNF-α (IFN/TNF) results in increased paracellular permeability. To identify relevant proteins mediating barrier disruption, we performed proximity-dependent biotinylation (BioID) of occludin and found that tagging of MARCKS-related protein (MRP; also known as MARCKSL1) increased ∼20-fold following IFN/TNF administration. GFP-MRP was focused at the lateral cell membrane and its overexpression potentiated the physiological response of the tight junction barrier to cytokines. However, deletion of MRP did not abrogate the cytokine responses, suggesting that MRP is not required in the occludin-dependent IFN/TNF response. Instead, our results reveal a key role for MRP in epithelial cells in control of multiple actin-based structures, likely by regulation of integrin signaling. Changes in focal adhesion organization and basal actin stress fibers in MRP-knockout (KO) cells were reminiscent of those seen in FAK-KO cells. In addition, we found alterations in cell-cell interactions in MRP-KO cells associated with increased junctional tension, suggesting that MRP may play a role in focal adhesion-adherens junction cross talk. Together, our results are consistent with a key role for MRP in cytoskeletal organization of cell contacts in epithelial cells. © 2018. Published by The Company of Biologists Ltd.

MicroRNA-122a Regulates Zonulin by Targeting EGFR in Intestinal Epithelial Dysfunction.

Science.gov (United States)

Zhang, Bin; Tian, Yinghai; Jiang, Ping; Jiang, Yanqiong; Li, Chao; Liu, Ting; Zhou, Rujian; Yang, Ning; Zhou, Xinke; Liu, Zhihua

2017-01-01

This study aimed to investigate the role of microRNA (miR)-122a in regulating zonulin during the modulation of intestinal barrier. Zonulin proteins and their target gene expression were analyzed in miR-122a-overexpressing cell lines and in the target gene of epidermal growth factor receptor (EGFR). An mmu-miR-122a intestinal epithelial conditional transgenic (miR-122a-TG) mouse model was established to investigate EGFR and zonulin expression. MiR-122a was also detected in the clinical specimens of inflammatory bowel disease. EGFR was identified as a target gene of miR-122a. The expression level of miR-122a was positively correlated with that of zonulin. The expression level of zonulin was significantly increased, whereas the expression level of EGFR was significantly decreased in the miR-122a-TG mice and in the corresponding primary epithelial culture (P zonulin by targeting EGFR, which increased the intestinal epithelial permeability in vivo and in vitro. © 2017 The Author(s). Published by S. Karger AG, Basel.

Comparison of the effects of ophthalmic solutions on human corneal epithelial cells using fluorescent dyes.

Science.gov (United States)

Xu, Manlong; Sivak, Jacob G; McCanna, David J

2013-11-01

To investigate the effect of differently preserved ophthalmic solutions on the viability and barrier function of human corneal epithelial cells (HCEC) using fluorescent dyes. HCEC monolayers were exposed to the ophthalmic solutions containing benzalkonium chloride (BAK), edetate disodium, polyquad, stabilized oxychloro complex (Purite), sodium perborate, or sorbic acid for 5 min, 15 min, and 1 h. At 24 h after exposure, the cultures were assessed for metabolic activity using alamarBlue. The enzyme activity, membrane integrity, and apoptosis were evaluated using confocal microscopy. Barrier function was assessed using sodium fluorescein. The metabolic assay showed that the BAK-preserved ophthalmic solutions significantly reduced cell viability after a 5-min exposure compared to the phosphate buffered saline treated control (POphthalmic solutions with new preservatives had varying time-dependent adverse effects on cell viability, and the preservative-free solution had the least effect on HCEC. Sodium fluorescein permeability showed that HCEC monolayers treated with BAK-preserved solutions were more permeable to sodium fluorescein than those treated by the other ophthalmic solutions (Psolutions had greater adverse effects on metabolic activity, enzyme activity, membrane integrity, cell viability, and barrier function than the solutions that were not preserved with BAK. Our study suggests that BAK-free especially, preservative-free ophthalmic solutions are safer alternatives to BAK-preserved ones.

Sodium caprate transiently opens claudin-5-containing barriers at tight junctions of epithelial and endothelial cells

DEFF Research Database (Denmark)

Del Vecchio, Giovanna; Tscheik, Christian; Tenz, Kareen

2012-01-01

Claudin-5 is a tight junction (TJ) protein which limits the diffusion of small hydrophilic molecules. Thus, it represents a potential pharmacological target to improve drug delivery to the tissues protected by claudin-5-dependent barriers. Sodium caprate is known as an absorption enhancer which...... opens the paracellular space acting on TJ proteins and actin cytoskeleton. Its action on claudin-5 is not understood so far. Epithelial and endothelial systems were used to evaluate the effect of caprate on claudin-5 in TJ-free cells and on claudin-5 fully integrated in TJ. To this aim, confocal...... of endothelial and epithelial cells. In conclusion, the study further elucidates the cellular effects of caprate at the tight junctions....

Crystalline structure of pulverized dental calculus induces cell death in oral epithelial cells.

Science.gov (United States)

Ziauddin, S M; Yoshimura, A; Montenegro Raudales, J L; Ozaki, Y; Higuchi, K; Ukai, T; Kaneko, T; Miyazaki, T; Latz, E; Hara, Y

2018-06-01

Dental calculus is a mineralized deposit attached to the tooth surface. We have shown that cellular uptake of dental calculus triggers nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, leading to the processing of the interleukin-1β precursor into its mature form in mouse and human phagocytes. The activation of the NLRP3 inflammasome also induced a lytic form of programmed cell death, pyroptosis, in these cells. However, the effects of dental calculus on other cell types in periodontal tissue have not been investigated. The aim of this study was to determine whether dental calculus can induce cell death in oral epithelial cells. HSC-2 human oral squamous carcinoma cells, HOMK107 human primary oral epithelial cells and immortalized mouse macrophages were exposed to dental calculus or 1 of its components, hydroxyapatite crystals. For inhibition assays, the cells were exposed to dental calculus in the presence or absence of cytochalasin D (endocytosis inhibitor), z-YVAD-fmk (caspase-1 inhibitor) or glyburide (NLRP3 inflammasome inhibitor). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release and staining with propidium iodide. Tumor necrosis factor-α production was quantified by enzyme-linked immunosorbent assay. Oral epithelial barrier function was examined by permeability assay. Dental calculus induced cell death in HSC-2 cells, as judged by LDH release and propidium iodide staining. Dental calculus also induced LDH release from HOMK107 cells. Following heat treatment, dental calculus lost its capacity to induce tumor necrosis factor-α in mouse macrophages, but could induce LDH release in HSC-2 cells, indicating a major role of inorganic components in cell death. Hydroxyapatite crystals also induced cell death in both HSC-2 and HOMK107 cells, as judged by LDH release, indicating the capacity of crystal particles to induce cell death. Cell death induced by dental

The role of JAM-A in inflammatory bowel disease: unrevealing the ties that bind.

Science.gov (United States)

Vetrano, Stefania; Danese, Silvio

2009-05-01

Tight junctions (TJ) are junctional proteins whose function is to maintain an intact intestinal epithelial barrier and regulate the paracellular movement of water and solutes. Altered TJ structure and epithelial permeability are observed in inflammatory bowel disease and seem to have an important role in the pathogenesis of these diseases. Junctional adhesion molecule-A (JAM-A) is a protein expressed at tight junctions of epithelial and endothelial cells, as well as on circulating leukocytes. Its function at tight junctions appears to be crucial as an extracellular adhesive molecule in the direct regulation of intestinal barrier function. This review focuses on the role of JAM-A in controlling mucosal homeostasis by regulating the integrity and permeability of epithelial barrier function.

Medroxyprogesterone acetate and levonorgestrel increase genital mucosal permeability and enhance susceptibility to genital herpes simplex virus type 2 infection.

Science.gov (United States)

Quispe Calla, N E; Vicetti Miguel, R D; Boyaka, P N; Hall-Stoodley, L; Kaur, B; Trout, W; Pavelko, S D; Cherpes, T L

2016-11-01

Depot-medroxyprogesterone acetate (DMPA) is a hormonal contraceptive especially popular in areas with high prevalence of HIV and other sexually transmitted infections (STI). Although observational studies identify DMPA as an important STI risk factor, mechanisms underlying this connection are undefined. Levonorgestrel (LNG) is another progestin used for hormonal contraception, but its effect on STI susceptibility is much less explored. Using a mouse model of genital herpes simplex virus type 2 (HSV-2) infection, we herein found that DMPA and LNG similarly reduced genital expression of the desmosomal cadherin desmoglein-1α (DSG1α), enhanced access of inflammatory cells to genital tissue by increasing mucosal epithelial permeability, and increased susceptibility to viral infection. Additional studies with uninfected mice revealed that DMPA-mediated increases in mucosal permeability promoted tissue inflammation by facilitating endogenous vaginal microbiota invasion. Conversely, concomitant treatment of mice with DMPA and intravaginal estrogen restored mucosal barrier function and prevented HSV-2 infection. Evaluating ectocervical biopsy tissue from women before and 1 month after initiating DMPA remarkably revealed that inflammation and barrier protection were altered by treatment identically to changes seen in progestin-treated mice. Together, our work reveals DMPA and LNG diminish the genital mucosal barrier; a first-line defense against all STI, but may offer foundation for new contraceptive strategies less compromising of barrier protection.

Effects of insulin combined with idebenone on blood-brain barrier permeability in diabetic rats.

Science.gov (United States)

Sun, Yan-Na; Liu, Li-Bo; Xue, Yi-Xue; Wang, Ping

2015-04-01

This study investigates the effect of insulin combined with idebenone on blood-brain barrier (BBB) permeability in experimental streptozotocin-induced diabetic rats as well as the underlying mechanisms. With a diabetic rat model, we show that insulin and idebenone normalize body weight and water intake and restore BBB permeability and that their combination displays a synergistic effect. The results from transmission electron microscopy show that the combination of insulin and idebenone significantly closed the tight junction (TJ) in diabetic rats. The results from Western blotting in diabetic rats show that the upregulation of TJ-associated proteins occludin, and zonula occludens (ZO)-1 caused by the combination of insulin and idebenone is more remarkable than that with either agent alone. In addition, the activations of reactive oxygen species (ROS) and advanced glycation end products (AGEs) and the expression levels of receptors for advanced glycation end-products (RAGE) and nuclear factor-κB (NF-κB) were significantly decreased after treatment with insulin and idebenone in diabetic rats. These results suggest that the combination of insulin and idebenone could decrease the BBB permeability in diabetic rats by upregulating the expression of occludin, claudin-5, and ZO-1 and that the ROS/AGE/RAGE/NF-κB signal pathway might be involved in the process. © 2014 Wiley Periodicals, Inc.

Introduction for the special issue on recent advances in drug delivery across tissue barriers.

Science.gov (United States)

Mrsny, Randall J; Brayden, David J

2016-01-01

This special issue of Tissue Barriers contains a series of reviews with the common theme of how biological barriers established at epithelial tissues limit the uptake of macromolecular therapeutics. By improving our functional understanding of these barriers, the majority of the authors have highlighted potential strategies that might be applied to the non-invasive delivery of biopharmaceuticals that would otherwise require an injection format for administration. Half of the articles focus on the potential of particular technologies to assist oral delivery of peptides, proteins and other macromolecules. These include use of prodrug chemistry to improve molecule stability and permeability, and the related potential for oral delivery of poorly permeable agents by cell-penetrating peptides and dendrimers. Safety aspects of intestinal permeation enhancers are discussed, along with the more recent foray into drug-device combinations as represented by intestinal microneedles and externally-applied ultrasound. Other articles highlight the crossover between food research and oral delivery based on nanoparticle technology, while the final one provides a fascinating interpretation of the physiological problems associated with subcutaneous insulin delivery and how inefficient it is at targeting the liver.

The role of L-type amino acid transporters in the uptake of glyphosate across mammalian epithelial tissues.

Science.gov (United States)

Xu, Jiaqiang; Li, Gao; Wang, Zhuoyi; Si, Luqin; He, Sijie; Cai, Jialing; Huang, Jiangeng; Donovan, Maureen D

2016-02-01

Glyphosate is one of the most commonly used herbicides worldwide due to its broad spectrum of activity and reported low toxicity to humans. Glyphosate has an amino acid-like structure that is highly polar and shows low bioavailability following oral ingestion and low systemic toxicity following intravenous exposures. Spray applications of glyphosate in agricultural or residential settings can result in topical or inhalation exposures to the herbicide. Limited systemic exposure to glyphosate occurs following skin contact, and pulmonary exposure has also been reported to be low. The results of nasal inhalation exposures, however, have not been evaluated. To investigate the mechanisms of glyphosate absorption across epithelial tissues, the permeation of glyphosate across Caco-2 cells, a gastrointestinal epithelium model, was compared with permeation across nasal respiratory and olfactory tissues excised from cows. Saturable glyphosate uptake was seen in all three tissues, indicating the activity of epithelial transporters. The uptake was shown to be ATP and Na(+) independent, and glyphosate permeability could be significantly reduced by the inclusion of competitive amino acids or specific LAT1/LAT2 transporter inhibitors. The pattern of inhibition of glyphosate permeability across Caco-2 and nasal mucosal tissues suggests that LAT1/2 play major roles in the transport of this amino-acid-like herbicide. Enhanced uptake into the epithelial cells at barrier mucosae, including the respiratory and gastrointestinal tracts, may result in more significant local and systemic effects than predicted from glyphosate's passive permeability, and enhanced uptake by the olfactory mucosa may result in further CNS disposition, potentially increasing the risk for brain-related toxicities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prediction of Groundwater Quality Improvement Down-Gradient of In Situ Permeable Treatment Barriers and Fully-Remediated Source Zones. ESTCP Cost and Performance Report

National Research Council Canada - National Science Library

Johnson, Paul C; Carlson, Pamela M; Dahlen, Paul

2008-01-01

In situ permeable treatment barriers (PTB) are designed so that contaminated groundwater flows through an engineered treatment zone within which contaminants are eliminated or the concentrations are significantly reduced...

Prolonged phonation impairs the integrity and barrier function of porcine vocal fold epithelium: a preliminary study.

Science.gov (United States)

Zhang, Chi; Paddock, Kieran; Chou, Adriana; Scholp, Austin; Gong, Ting; Jiang, Jack J

2018-04-18

Voice abuse is known to be a common risk factor of voice disorders and prolonged; high-intensity phonation has been shown to damage the vocal fold epithelium. We aim to evaluate the effects of phonation on the integrity and barrier function of vocal fold epithelium using a porcine laryngeal model. Ex vivo porcine larynges were phonated at low intensity or high intensity for 15, 30, or 60 min within 4 h after harvest. Vocal fold epithelium was visualized using transmission electron microscopy (TEM). The barrier function of vocal fold epithelium was evaluated by measuring the permeability to model molecules, fluorescein (376 Da), and fluorescein isothiocyanate (FITC)-dextrans of 4000 and 10,000 Da (FD4, FD10), in a Franz diffusing cell. Cell death and dilated intercellular space after phonation were observed using TEM. Thickness of vocal fold epithelium was significantly reduced after low-intensity phonation for 30 and 60 min and high-intensity phonation for 15, 30, and 60 min. Epithelial permeability to fluorescein was significantly increased after low-intensity phonation for 30 and 60 min, and high-intensity phonation. Permeability to FD4 was significantly increased after high-intensity phonation for 30 and 60 min. Phonation did not alter the permeability to FD10 significantly. Long-duration phonation destroys the integrity and barrier function of vocal fold epithelium. These effects likely make vocal folds more vulnerable to other environmental irritants, such as tobacco smoke, reflux components, allergens, and inhaled pollutants. Destroyed barrier function may be an important factor in the pathogenesis of voice lesions related to voice abuse.

Permeable Reactive Barriers: a multidisciplinary approach of a new emerging sustainable groundwater treatment technology

Energy Technology Data Exchange (ETDEWEB)

Diels, L.; Bastiaens, L. [Vito, Mol (BL); O' Hannessin, S. [EnviroMetal Technologies Inc., Ontario (Canada); Cortina, J.L. [Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. d' Enginyeria Quimica; Alvarez, P.J. [Univ. of Iowa, Iowa-City (United States). Center for Biocatalysis and Bioprocessing; Ebert, M. [Christian-Albrechts Univ. Kiel (Germany). Inst. fuer Geowissenschaften; Schad, H. [I.M.E.S. GmbH, Amtzell (Germany)

2003-07-01

Permeable reactive barriers or zones are becoming an interesting sustainable and cost-effective technology for in situ treatment of contaminated groundwater. The technology is based on chemical processes as the dehalogenating activity of zerovalent iron, biological processes in bioscreens or reactive zones and on sorption technology (e.g. heavy metal adsorption or adsorption on granular activated carbon). Three technical sessions will be devoted to this nowadays becoming mature technology. This special session intends to pay attention to the discussion about some questions related to PRBs. These include the sustainability (e.g. life time and clogging) especially for zerovalent iron barriers, the need and quality of feasibility tests, drawbacks and restrictions of PRBs. Combined with long term performance monitoring os these systems will be discussed. Further attention will be paid to cost evaluation and the relationship between zerovalent barriers and bacterial growth. Also attention will be paid to new reactive materials (e.g. activated carbon for organics and inorganic materials for heavy metals) and consequences (e.g. environmental impact). Finally the session will combine al these approaches in a discussion about combined barriers or multibarriers for treatment of mixed pollution (e.g. landfill leachates contaminated groundwater). Specialists involved in these subjects will introduce these topics and allow for a large and intensive discussion to improve future applications of this technology. (orig.)

Blood-retinal barrier glycerol permeability in diabetic macular edema and healthy eyes: estimations from macular volume changes after peroral glycerol

DEFF Research Database (Denmark)

Thornit, Dorte Nellemann; Vinten, Carl Martin; Sander, Birgit

2010-01-01

PURPOSE: To compare the changes in macular volume (MV) between healthy subjects and patients with diabetic macular edema (DME) after an osmotic load and to determine the glycerol permeability (P(gly)) of the blood-retinal barrier (BRB). METHODS: In this unmasked study, 13 patients with DME and 5...

Early effects of gliadin on enterocyte intracellular signalling involved in intestinal barrier function.

Science.gov (United States)

Clemente, M G; De Virgiliis, S; Kang, J S; Macatagney, R; Musu, M P; Di Pierro, M R; Drago, S; Congia, M; Fasano, A

2003-02-01

Despite the progress made in understanding the immunological aspects of the pathogenesis of coeliac disease (CD), the early steps that allow gliadin to cross the intestinal barrier are still largely unknown. The aim of this study was to establish whether gliadin activates a zonulin dependent enterocyte intracellular signalling pathway(s) leading to increased intestinal permeability. The effect of gliadin on the enterocyte actin cytoskeleton was studied on rat intestinal epithelial (IEC-6) cell cultures by fluorescence microscopy and spectrofluorimetry. Zonulin concentration was measured on cell culture supernatants by enzyme linked immunosorbent assay. Transepithelial intestinal resistance (Rt) was measured on ex vivo intestinal tissues mounted in Ussing chambers. Incubation of cells with gliadin led to a reversible protein kinase C (PKC) mediated actin polymerisation temporarily coincident with zonulin release. A significant reduction in Rt was observed after gliadin addition on rabbit intestinal mucosa mounted in Ussing chambers. Pretreatment with the zonulin inhibitor FZI/0 abolished the gliadin induced actin polymerisation and Rt reduction but not zonulin release. Gliadin induces zonulin release in intestinal epithelial cells in vitro. Activation of the zonulin pathway by PKC mediated cytoskeleton reorganisation and tight junction opening leads to a rapid increase in intestinal permeability.

Permeability of the small intestine after intra-arterial injection of histamine-type mediators and irradiation

International Nuclear Information System (INIS)

Kingham, J.G.C.; Loehry, C.A.

1976-01-01

Permeability and selectivity of rabbit small intestine were estimated by a perfusion technique after intra-arterial injection of histamine-type mediators and an intestinal dose of 1.5 Mr gamma irradiation. It was shown that the histamine-type mediators caused an increase in capillary permeability which produced an overall moderate increase in transmucosal permeability with a moderate loss of selectivity. Local intestinal irradiation caused a very marked increase in permeability and a profound loss of selectivity. It was felt that this was produced partly by an increase in capillary permeability but largely by damage to the epithelial basement membrane. It is concluded that the intestinal capillary endothelium is both rate-limiting and selective, though not to a major degree in either case. The epithelial basement membrane, however, appears to be both rate-limiting and markedly selective. (author)

House Dust Mite Der p 1 Effects on Sinonasal Epithelial Tight Junctions

Science.gov (United States)

Henriquez, Oswaldo A.; Beste, Kyle Den; Hoddeson, Elizabeth K.; Parkos, Charles A.; Nusrat, Asma; Wise, Sarah K.

2013-01-01

Background Epithelial permeability is highly dependent upon the integrity of tight junctions, cell-cell adhesion complexes located at the apical aspect of the lateral membrane of polarized epithelial cells. We hypothesize that sinonasal epithelial exposure to Der p 1 house dust mite antigen decreases expression of tight junction proteins (TJPs), representing a potential mechanism for increased permeability and presentation of antigens across the sinonasal epithelial layer. Methods Confluent cultured primary human sinonasal epithelial cells were exposed to recombinant Der p 1 antigen versus control, and transepithelial resistance measurements were performed over 24 hours. Antibody staining for a panel of tight junction proteins was examined with immunofluorescence/confocal microscopy and Western blotting. Tissue for these experiments was obtained from 4 patients total. Results Der p 1 exposed sinonasal cells showed a marked decrease in transepithelial resistance when compared to control cells. In addition, results of Western immunoblot and immunofluorescent labeling demonstrated decreased expression of TJPs claudin-1 and junction adhesion molecule-A (JAM-A) in Der p 1 exposed cultured sinonasal cells versus controls. Conclusion Der p 1 antigen exposure decreases sinonasal epithelium TJP expression, most notably seen in JAM-A and claudin-1 in these preliminary experiments. This decreased TJP expression likely contributes to increased epithelial permeability and represents a potential mechanism for transepithelial antigen exposure in allergic rhinitis. PMID:23592402

MicroRNA-122a Regulates Zonulin by Targeting EGFR in Intestinal Epithelial Dysfunction

Directory of Open Access Journals (Sweden)

Bin Zhang

2017-06-01

Full Text Available Background/Aims: This study aimed to investigate the role of microRNA (miR-122a in regulating zonulin during the modulation of intestinal barrier. Methods: Zonulin proteins and their target gene expression were analyzed in miR-122a-overexpressing cell lines and in the target gene of epidermal growth factor receptor (EGFR. An mmu-miR-122a intestinal epithelial conditional transgenic (miR-122a-TG mouse model was established to investigate EGFR and zonulin expression. MiR-122a was also detected in the clinical specimens of inflammatory bowel disease. Results: EGFR was identified as a target gene of miR-122a. The expression level of miR-122a was positively correlated with that of zonulin. The expression level of zonulin was significantly increased, whereas the expression level of EGFR was significantly decreased in the miR-122a-TG mice and in the corresponding primary epithelial culture (P < 0.05. These results were consistent with the data of the clinical specimens. Conclusions: miR-122a could be a positive factor of zonulin by targeting EGFR, which increased the intestinal epithelial permeability in vivo and in vitro.

Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water

Energy Technology Data Exchange (ETDEWEB)

Yang Ji, E-mail: yangji@ecust.edu.cn [School of Resources and Environmental Engineering, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); Cao Limei; Guo Rui; Jia Jinping [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2010-12-15

Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m{sup 2} g{sup -1}, the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly.

Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water

International Nuclear Information System (INIS)

Yang Ji; Cao Limei; Guo Rui; Jia Jinping

2010-01-01

Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m 2 g -1 , the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly.

Oxidation of volatile organic compound vapours by potassium permanganate in a horizontal permeable reactive barrier under unsaturated conditions: experiments and modeling

NARCIS (Netherlands)

Ghareh Mahmoodlu, Mojtaba|info:eu-repo/dai/nl/357287746

2014-01-01

In this research we evaluated the potential of using solid potassium permanganate to create a horizontal permeable reactive barrier (HPRB) for oxidizing VOC vapours in the unsaturated zone. We have performed batch experiments, short column, and long column experiments, and have fully analyzed the

Glycoprotein A33 deficiency: a new mouse model of impaired intestinal epithelial barrier function and inflammatory disease

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Benjamin B. Williams

2015-08-01

Full Text Available The cells of the intestinal epithelium provide a selectively permeable barrier between the external environment and internal tissues. The integrity of this barrier is maintained by tight junctions, specialised cell-cell contacts that permit the absorption of water and nutrients while excluding microbes, toxins and dietary antigens. Impairment of intestinal barrier function contributes to multiple gastrointestinal disorders, including food hypersensitivity, inflammatory bowel disease (IBD and colitis-associated cancer (CAC. Glycoprotein A33 (GPA33 is an intestinal epithelium-specific cell surface marker and member of the CTX group of transmembrane proteins. Roles in cell-cell adhesion have been demonstrated for multiple CTX family members, suggesting a similar function for GPA33 within the gastrointestinal tract. To test a potential requirement for GPA33 in intestinal barrier function, we generated Gpa33−/− mice and subjected them to experimental regimens designed to produce food hypersensitivity, colitis and CAC. Gpa33−/− mice exhibited impaired intestinal barrier function. This was shown by elevated steady-state immunosurveillance in the colonic mucosa and leakiness to oral TRITC-labelled dextran after short-term exposure to dextran sodium sulphate (DSS to injure the intestinal epithelium. Gpa33−/− mice also exhibited rapid onset and reduced resolution of DSS-induced colitis, and a striking increase in the number of colitis-associated tumours produced by treatment with the colon-specific mutagen azoxymethane (AOM followed by two cycles of DSS. In contrast, Gpa33−/− mice treated with AOM alone showed no increase in sporadic tumour formation, indicating that their increased tumour susceptibility is dependent on inflammatory stimuli. Finally, Gpa33−/− mice displayed hypersensitivity to food allergens, a common co-morbidity in humans with IBD. We propose that Gpa33−/− mice provide a valuable model to study the mechanisms

Loss of guanylyl cyclase C (GCC signaling leads to dysfunctional intestinal barrier.

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Xiaonan Han

2011-01-01

Full Text Available Guanylyl Cyclase C (GCC signaling via uroguanylin (UGN and guanylin activation is a critical mediator of intestinal fluid homeostasis, intestinal cell proliferation/apoptosis, and tumorigenesis. As a mechanism for some of these effects, we hypothesized that GCC signaling mediates regulation of intestinal barrier function.Paracellular permeability of intestinal segments was assessed in wild type (WT and GCC deficient (GCC-/- mice with and without lipopolysaccharide (LPS challenge, as well as in UGN deficient (UGN-/- mice. IFNγ and myosin light chain kinase (MLCK levels were determined by real time PCR. Expression of tight junction proteins (TJPs, phosphorylation of myosin II regulatory light chain (MLC, and STAT1 activation were examined in intestinal epithelial cells (IECs and intestinal mucosa. The permeability of Caco-2 and HT-29 IEC monolayers, grown on Transwell filters was determined in the absence and presence of GCC RNA interference (RNAi. We found that intestinal permeability was increased in GCC-/- and UGN-/- mice compared to WT, accompanied by increased IFNγ levels, MLCK and STAT1 activation in IECs. LPS challenge promotes greater IFNγ and STAT1 activation in IECs of GCC-/- mice compared to WT mice. Claudin-2 and JAM-A expression were reduced in GCC deficient intestine; the level of phosphorylated MLC in IECs was significantly increased in GCC-/- and UGN-/- mice compared to WT. GCC knockdown induced MLC phosphorylation, increased permeability in IEC monolayers under basal conditions, and enhanced TNFα and IFNγ-induced monolayer hyperpermeability.GCC signaling plays a protective role in the integrity of the intestinal mucosal barrier by regulating MLCK activation and TJ disassembly. GCC signaling activation may therefore represent a novel mechanism in maintaining the small bowel barrier in response to injury.

Enterocyte-specific epidermal growth factor prevents barrier dysfunction and improves mortality in murine peritonitis.

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Clark, Jessica A; Gan, Heng; Samocha, Alexandr J; Fox, Amy C; Buchman, Timothy G; Coopersmith, Craig M

2009-09-01

Systemic administration of epidermal growth factor (EGF) decreases mortality in a murine model of septic peritonitis. Although EGF can have direct healing effects on the intestinal mucosa, it is unknown whether the benefits of systemic EGF in peritonitis are mediated through the intestine. Here, we demonstrate that enterocyte-specific overexpression of EGF is sufficient to prevent intestinal barrier dysfunction and improve survival in peritonitis. Transgenic FVB/N mice that overexpress EGF exclusively in enterocytes (IFABP-EGF) and wild-type (WT) mice were subjected to either sham laparotomy or cecal ligation and puncture (CLP). Intestinal permeability, expression of the tight junction proteins claudins-1, -2, -3, -4, -5, -7, and -8, occludin, and zonula occludens-1; villus length; intestinal epithelial proliferation; and epithelial apoptosis were evaluated. A separate cohort of mice was followed for survival. Peritonitis induced a threefold increase in intestinal permeability in WT mice. This was associated with increased claudin-2 expression and a change in subcellular localization. Permeability decreased to basal levels in IFABP-EGF septic mice, and claudin-2 expression and localization were similar to those of sham animals. Claudin-4 expression was decreased following CLP but was not different between WT septic mice and IFABP-EGF septic mice. Peritonitis-induced decreases in villus length and proliferation and increases in apoptosis seen in WT septic mice did not occur in IFABP-EGF septic mice. IFABP-EGF mice had improved 7-day mortality compared with WT septic mice (6% vs. 64%). Since enterocyte-specific overexpression of EGF is sufficient to prevent peritonitis-induced intestinal barrier dysfunction and confers a survival advantage, the protective effects of systemic EGF in septic peritonitis appear to be mediated in an intestine-specific fashion.

Effect of wild-type Shigella species and attenuated Shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release.

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Maria Fiorentino

Full Text Available Bacterial dysentery due to Shigella species is a major cause of morbidity and mortality worldwide. The pathogenesis of Shigella is based on the bacteria's ability to invade and replicate within the colonic epithelium, resulting in severe intestinal inflammatory response and epithelial destruction. Although the mechanisms of pathogenesis of Shigella in the colon have been extensively studied, little is known on the effect of wild-type Shigella on the small intestine and the role of the host response in the development of the disease. Moreover, to the best of our knowledge no studies have described the effects of apically administered Shigella flexneri 2a and S. dysenteriae 1 vaccine strains on human small intestinal enterocytes. The aim of this study was to assess the coordinated functional and immunological human epithelial responses evoked by strains of Shigella and candidate vaccines on small intestinal enterocytes. To model the interactions of Shigella with the intestinal mucosa, we apically exposed monolayers of human intestinal Caco2 cells to increasing bacterial inocula. We monitored changes in paracellular permeability, examined the organization of tight-junctions and the pro-inflammatory response of epithelial cells. Shigella infection of Caco2 monolayers caused severe mucosal damage, apparent as a drastic increase in paracellular permeability and disruption of tight junctions at the cell-cell boundary. Secretion of pro-inflammatory IL-8 was independent of epithelial barrier dysfunction. Shigella vaccine strains elicited a pro-inflammatory response without affecting the intestinal barrier integrity. Our data show that wild-type Shigella infection causes a severe alteration of the barrier function of a small intestinal cell monolayer (a proxy for mucosa and might contribute (along with enterotoxins to the induction of watery diarrhea. Diarrhea may be a mechanism by which the host attempts to eliminate harmful bacteria and transport them

c-Kit mutation reduce intestinal epithelial cell proliferation and migration, but not influence intestinal permeability stimulated by lipopolysaccharide.

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Xue, Hong; Wang, Feng Yun; Kang, Qian; Tang, Xu Dong

2018-06-20

The proto-oncogene c-kit, as a marker of interstitial cells of Cajal (ICCs) in the gastrointestinal tract, plays an important role in the ICCs. Although limited evidences showed c-kit is present in the colonic epithelium but its roles remain unclear. In the present study, we aimed to investigate the expression, location and function of c-kit in the intestinal epithelium. Immunofluorescence, western blotting, and RT-PCR were performed to detect the expression and location of c-kit in the intestinal mucosa of WT mice. We investigated intestinal epithelial proliferation and migration in vivo by performing 5-Bromodeoxyuridine (BrdU) incorporation and Ki-67 staining in WT and Wads m/m mice. An Ussing chamber with fluorescein-isothiocyanate dextran 4000 was used to detect the transepithelial electric resistance (TER), short circuit current (ISC) and permeability across ex vivo colon segments under control and endotoxaemia conditions. We demonstrated that c-kit was located and expressed in the gut crypt compartment in WT mice, which was demonstrated in the c-kit mutant mice (Wads m/m ). In addition, both the number of proliferating cells and the percentage of the distance migrated were lower in the Wads m/m mice than those in the WT mice. Moreover, the intestinal permeability, TER and tight junction were unaltered in the Wads m/m mice under endotoxic conditions compared with those in both the control condition and the WT mice. Altogether, these observations imply that the expression of c-kit in the colonic epithelium is involved in the proliferation and permeability of the colonic epithelium. Copyright © 2018. Published by Elsevier GmbH.

The world of epithelial sheets.

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Honda, Hisao

2017-06-01

An epithelium is a layer of closely connected cells covering the body or lining a body cavity. In this review, several fundamental questions are addressed regarding the epithelium. (i) While an epithelium functions as barrier against the external environment, how is barrier function maintained during its construction? (ii) What determines the apical and basal sides of epithelial layer? (iii) Is there any relationship between the apical side of the epithelium and the apical membrane of an epithelial cell? (iv) Why are hepatocytes (liver cells) called epithelial, even though they differ completely from column-like shape of typical epithelial cells? Keeping these questions in mind, multiple shapes of epithelia were considered, extracting a few of their elemental processes, and constructing a virtual world of epithelia by combining them. Epithelial cells were also classified into several types based on the number of apical domains of each cell. In addition, an intracellular organelle was introduced within epithelial cells, the vacuolar apical compartment (VAC), which is produced within epithelial cells surrounded by external cell matrix (ECM). The VAC interacts with areas of cell-cell contact of the cell surface membrane and is converted to apical membrane. The properties of VACs enable us to answer the initial questions posed above. Finally, the genetic and molecular mechanisms of epithelial morphogenesis are discussed. © 2017 Japanese Society of Developmental Biologists.

Retinal pathology is associated with increased blood-retina barrier permeability in a diabetic and hypercholesterolaemic pig model: Beneficial effects of the LpPLA2 inhibitor Darapladib.

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Acharya, Nimish K; Qi, Xin; Goldwaser, Eric L; Godsey, George A; Wu, Hao; Kosciuk, Mary C; Freeman, Theresa A; Macphee, Colin H; Wilensky, Robert L; Venkataraman, Venkat; Nagele, Robert G

2017-05-01

Using a porcine model of diabetes mellitus and hypercholesterolaemia, we previously showed that diabetes mellitus and hypercholesterolaemia is associated with a chronic increase in blood-brain barrier permeability in the cerebral cortex, leading to selective binding of immunoglobulin G and deposition of amyloid-beta 1-42 peptide in pyramidal neurons. Treatment with Darapladib (GlaxoSmithKline, SB480848), an inhibitor of lipoprotein-associated phospholipase-A2, alleviated these effects. Here, investigation of the effects of chronic diabetes mellitus and hypercholesterolaemia on the pig retina revealed a corresponding increased permeability of the blood-retina barrier coupled with a leak of plasma components into the retina, alterations in retinal architecture, selective IgG binding to neurons in the ganglion cell layer, thinning of retinal layers due to cell loss and increased glial fibrillary acidic protein expression in Müller cells, all of which were curtailed by treatment with Darapladib. These findings suggest that chronic diabetes mellitus and hypercholesterolaemia induces increased blood-retina barrier permeability that may be linked to altered expression of blood-retina barrier-associated tight junction proteins, claudin and occludin, leading to structural changes in the retina consistent with diabetic retinopathy. Additionally, results suggest that drugs with vascular anti-inflammatory properties, such as Darapladib, may have beneficial effects on eye diseases strongly linked to vascular abnormalities such as diabetic retinopathy and age-related macular degeneration.

Epithelial Cell Damage Activates Bactericidal/Permeability Increasing-Protein (BPI Expression in Intestinal Epithelium

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Arjun Balakrishnan

2017-08-01

Full Text Available As the first line of defense against invading pathogen, intestinal epithelium produces various antimicrobial proteins (AMP that help in clearance of pathogen. Bactericidal/permeability-increasing protein (BPI is a 55 kDa AMP that is expressed in intestinal epithelium. Dysregulation of BPI in intestinal epithelium is associated with various inflammatory diseases like Crohn’s Disease, Ulcerative colitis, and Infectious enteritis’s. In this paper, we report a direct correlation between intestinal damage and BPI expression. In Caco-2 cells, we see a significant increase in BPI levels upon membrane damage mediated by S. aureus infection and pore-forming toxins (Streptolysin and Listeriolysin. Cells detect changes in potassium level as a Danger-associated molecular pattern associated with cell damage and induce BPI expression in a p38 dependent manner. These results are further supported by in vivo findings that the BPI expression in murine intestinal epithelium is induced upon infection with bacteria which cause intestinal damage (Salmonella Typhimurium and Shigella flexneri whereas mutants that do not cause intestinal damage (STM ΔfliC and STM ΔinvC did not induce BPI expression. Our results suggest that epithelial damage associated with infection act as a signal to induce BPI expression.

Improved Prediction of Blood-Brain Barrier Permeability Through Machine Learning with Combined Use of Molecular Property-Based Descriptors and Fingerprints.

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Yuan, Yaxia; Zheng, Fang; Zhan, Chang-Guo

2018-03-21

Blood-brain barrier (BBB) permeability of a compound determines whether the compound can effectively enter the brain. It is an essential property which must be accounted for in drug discovery with a target in the brain. Several computational methods have been used to predict the BBB permeability. In particular, support vector machine (SVM), which is a kernel-based machine learning method, has been used popularly in this field. For SVM training and prediction, the compounds are characterized by molecular descriptors. Some SVM models were based on the use of molecular property-based descriptors (including 1D, 2D, and 3D descriptors) or fragment-based descriptors (known as the fingerprints of a molecule). The selection of descriptors is critical for the performance of a SVM model. In this study, we aimed to develop a generally applicable new SVM model by combining all of the features of the molecular property-based descriptors and fingerprints to improve the accuracy for the BBB permeability prediction. The results indicate that our SVM model has improved accuracy compared to the currently available models of the BBB permeability prediction.

Bloodstream-To-Eye Infections Are Facilitated by Outer Blood-Retinal Barrier Dysfunction.

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Phillip S Coburn

Full Text Available The blood-retinal barrier (BRB functions to maintain the immune privilege of the eye, which is necessary for normal vision. The outer BRB is formed by tightly-associated retinal pigment epithelial (RPE cells which limit transport within the retinal environment, maintaining retinal function and viability. Retinal microvascular complications and RPE dysfunction resulting from diabetes and diabetic retinopathy cause permeability changes in the BRB that compromise barrier function. Diabetes is the major predisposing condition underlying endogenous bacterial endophthalmitis (EBE, a blinding intraocular infection resulting from bacterial invasion of the eye from the bloodstream. However, significant numbers of EBE cases occur in non-diabetics. In this work, we hypothesized that dysfunction of the outer BRB may be associated with EBE development. To disrupt the RPE component of the outer BRB in vivo, sodium iodate (NaIO3 was administered to C57BL/6J mice. NaIO3-treated and untreated mice were intravenously injected with 108 colony forming units (cfu of Staphylococcus aureus or Klebsiella pneumoniae. At 4 and 6 days postinfection, EBE was observed in NaIO3-treated mice after infection with K. pneumoniae and S. aureus, although the incidence was higher following S. aureus infection. Invasion of the eye was observed in control mice following S. aureus infection, but not in control mice following K. pneumoniae infection. Immunohistochemistry and FITC-dextran conjugate transmigration assays of human RPE barriers after infection with an exoprotein-deficient agr/sar mutant of S. aureus suggested that S. aureus exoproteins may be required for the loss of the tight junction protein, ZO-1, and for permeability of this in vitro barrier. Our results support the clinical findings that for both pathogens, complications which result in BRB permeability increase the likelihood of bacterial transmigration from the bloodstream into the eye. For S. aureus, however, BRB

Live Faecalibacterium prausnitzii Does Not Enhance Epithelial Barrier Integrity in an Apical Anaerobic Co-Culture Model of the Large Intestine

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Eva Maier

2017-12-01

Full Text Available Appropriate intestinal barrier maturation during infancy largely depends on colonization with commensal bacteria. Faecalibacterium prausnitzii is an abundant obligate anaerobe that colonizes during weaning and is thought to maintain colonic health throughout life. We previously showed that F. prausnitzii induced Toll-like receptor 2 (TLR2 activation, which is linked to enhanced tight junction formation. Therefore, we hypothesized that F. prausnitzii enhances barrier integrity, an important factor in appropriate intestinal barrier maturation. In order to test metabolically active bacteria, we used a novel apical anaerobic co-culture system that allows the survival of both obligate anaerobic bacteria and oxygen-requiring intestinal epithelial cells (Caco-2. The first aim was to optimize the culture medium to enable growth and active metabolism of F. prausnitzii while maintaining the viability and barrier integrity, as measured by trans-epithelial electrical resistance (TEER, of the Caco-2 cells. This was achieved by supplementing the apical cell culture medium with bacterial culture medium. The second aim was to test the effect of F. prausnitzii on TEER across Caco-2 cell layers. Live F. prausnitzii did not improve TEER, which indicates that its benefits are not via altering tight junction integrity. The optimization of the novel dual-environment co-culturing system performed in this research will enable the investigation of new probiotics originating from indigenous beneficial bacteria.

Live Faecalibacterium prausnitzii Does Not Enhance Epithelial Barrier Integrity in an Apical Anaerobic Co-Culture Model of the Large Intestine.

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Maier, Eva; Anderson, Rachel C; Roy, Nicole C

2017-12-12

Appropriate intestinal barrier maturation during infancy largely depends on colonization with commensal bacteria. Faecalibacterium prausnitzii is an abundant obligate anaerobe that colonizes during weaning and is thought to maintain colonic health throughout life. We previously showed that F. prausnitzii induced Toll-like receptor 2 (TLR2) activation, which is linked to enhanced tight junction formation. Therefore, we hypothesized that F. prausnitzii enhances barrier integrity, an important factor in appropriate intestinal barrier maturation. In order to test metabolically active bacteria, we used a novel apical anaerobic co-culture system that allows the survival of both obligate anaerobic bacteria and oxygen-requiring intestinal epithelial cells (Caco-2). The first aim was to optimize the culture medium to enable growth and active metabolism of F. prausnitzii while maintaining the viability and barrier integrity, as measured by trans-epithelial electrical resistance (TEER), of the Caco-2 cells. This was achieved by supplementing the apical cell culture medium with bacterial culture medium. The second aim was to test the effect of F. prausnitzii on TEER across Caco-2 cell layers. Live F. prausnitzii did not improve TEER, which indicates that its benefits are not via altering tight junction integrity. The optimization of the novel dual-environment co-culturing system performed in this research will enable the investigation of new probiotics originating from indigenous beneficial bacteria.

Combining Nitrilotriacetic Acid and Permeable Barriers for Enhanced Phytoextraction of Heavy Metals from Municipal Solid Waste Compost by and Reduced Metal Leaching.

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Zhao, Shulan; Jia, Lina; Duo, Lian

2016-05-01

Phytoextraction has the potential to remove heavy metals from contaminated soil, and chelants can be used to improve the capabilities of phytoextraction. However, environmentally persistent chelants can cause metal leaching and groundwater pollution. A column experiment was conducted to evaluate the viability of biodegradable nitrilotriacetic acid (NTA) to increase the uptake of heavy metals (Cd, Cr, Ni, Pb, Cu, and Zn) by L. in municipal solid waste (MSW) compost and to evaluate the effect of two permeable barrier materials, bone meal and crab shell, on metal leaching. The application of NTA significantly increased the concentrations and uptake of heavy metals in . The enhancement was more pronounced at higher dosages of NTA. In the 15 mmol kg NTA treatment using a crab shell barrier, the Cr and Ni concentrations in the plant shoots increased by approximately 8- and 10-fold, respectively, relative to the control. However, the addition of NTA also caused significant heavy metal leaching from the MSW compost. Bone meal and crab shell barriers positioned between the compost and the subsoil were effective in preventing metal leaching down through the soil profile by the retention of metals in the barrier. The application of a biodegradable chelant and the use of permeable barriers is a viable form of enhanced phytoextraction to increase the removal of metals and to reduce possible leaching. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

EMMPRIN modulates epithelial barrier function through a MMP-mediated occludin cleavage: implications in dry eye disease.

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Huet, Eric; Vallée, Benoit; Delbé, Jean; Mourah, Samia; Prulière-Escabasse, Virginie; Tremouilleres, Magali; Kadomatsu, Kenji; Doan, Serge; Baudouin, Christophe; Menashi, Suzanne; Gabison, Eric E

2011-09-01

Dry eye is a common disease that develops as a result of alteration of tear fluid, leading to osmotic stress and a perturbed epithelial barrier. Matrix metalloproteinase-9 (MMP-9) may be important in dry eye disease, as its genetic knockout conferred resistance to the epithelial disruption. We show that extracellular matrix metalloproteinase inducer (EMMPRIN; also termed CD147), an inducer of MMP expression, participates in the pathogenesis of dry eye through MMP-mediated cleavage of occludin, an important component of tight junctions. EMMPRIN expression was increased on the ocular surface of dry eye patients and correlated with those of MMP-9. High osmolarity in cell culture, mimicking dry eye conditions, increased both EMMPRIN and MMP-9 and resulted in the disruption of epithelial junctions through the cleavage of occludin. Exogenously added recombinant EMMPRIN had similar effects that were abrogated in the presence of the MMP inhibitor marimastat. Membrane occludin immunostaining was markedly increased in the apical corneal epithelium of both EMMPRIN and MMP-9 knock-out mice. Furthermore, an inverse correlation between EMMPRIN and occludin membrane staining was consistently observed both in vitro and in vivo as a function of corneal epithelial cells differentiation. These data suggest a possible role of EMMPRIN in regulating the amount of occludin at the cell surface in homeostasis beyond pathological situations such as dry eye disease, and EMMPRIN may be essential for the formation and maintenance of organized epithelial structure. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Delayed astrocytic contact with cerebral blood vessels in FGF-2 deficient mice does not compromise permeability properties at the developing blood-brain barrier.

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Saunders, Norman R; Dziegielewska, Katarzyna M; Unsicker, Klaus; Ek, C Joakim

2016-11-01

The brain functions within a specialized environment tightly controlled by brain barrier mechanisms. Understanding the regulation of barrier formation is important for understanding brain development and may also lead to finding new ways to deliver pharmacotherapies to the brain; access of many potentially promising drugs is severely hindered by these barrier mechanisms. The cellular composition of the neurovascular unit of the blood-brain barrier proper and their effects on regulation of its function are beginning to be understood. One hallmark of the neurovascular unit in the adult is the astroglial foot processes that tightly surround cerebral blood vessels. However their role in barrier formation is still unclear. In this study we examined barrier function in newborn, juvenile and adult mice lacking fibroblast growth factor-2 (FGF-2), which has been shown to result in altered astroglial differentiation during development. We show that during development of FGF-2 deficient mice the astroglial contacts with cerebral blood vessels are delayed compared with wild-type animals. However, this delay did not result in changes to the permeability properties of the blood brain barrier as assessed by exclusion of either small or larger sized molecules at this interface. In addition cerebral vessels were positive for tight-junction proteins and we observed no difference in the ultrastructure of the tight-junctions. The results indicate that the direct contact of astroglia processes to cerebral blood vessels is not necessary for either the formation of the tight-junctions or for basic permeability properties and function of the blood-brain barrier. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1201-1212, 2016. © 2016 Wiley Periodicals, Inc.

House dust mite allergen Der p 1 effects on sinonasal epithelial tight junctions.

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Henriquez, Oswaldo A; Den Beste, Kyle; Hoddeson, Elizabeth K; Parkos, Charles A; Nusrat, Asma; Wise, Sarah K

2013-08-01

Epithelial permeability is highly dependent upon the integrity of tight junctions, which are cell-cell adhesion complexes located at the apical aspect of the lateral membrane of polarized epithelial cells. We hypothesize that sinonasal epithelial exposure to Der p 1 house dust mite antigen decreases expression of tight junction proteins (TJPs), representing a potential mechanism for increased permeability and presentation of antigens across the sinonasal epithelial layer. Confluent cultured primary human sinonasal epithelial cells were exposed to recombinant Der p 1 antigen vs control, and transepithelial resistance measurements were performed over 24 hours. Antibody staining for a panel of TJPs was examined with immunofluorescence/confocal microscopy and Western blotting. Tissue for these experiments was obtained from 4 patients total. Der p 1 exposed sinonasal cells showed a marked decrease in transepithelial resistance when compared to control cells. In addition, results of Western immunoblot and immunofluorescent labeling demonstrated decreased expression of TJPs claudin-1 and junction adhesion molecule-A (JAM-A) in Der p 1-exposed cultured sinonasal cells vs controls. Der p 1 antigen exposure decreases sinonasal epithelium TJP expression, most notably seen in JAM-A and claudin-1 in these preliminary experiments. This decreased TJP expression likely contributes to increased epithelial permeability and represents a potential mechanism for transepithelial antigen exposure in allergic rhinitis. © 2013 ARS-AAOA, LLC.

Exogenous HIV-1 Nef upsets the IFN-γ-induced impairment of human intestinal epithelial integrity.

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Maria Giovanna Quaranta

Full Text Available The mucosal tissues play a central role in the transmission of HIV-1 infection as well as in the pathogenesis of AIDS. Despite several clinical studies reported intestinal dysfunction during HIV infection, the mechanisms underlying HIV-induced impairments of mucosal epithelial barrier are still unclear. It has been postulated that HIV-1 alters enterocytic function and HIV-1 proteins have been detected in several cell types of the intestinal mucosa. In the present study, we analyzed the effect of the accessory HIV-1 Nef protein on human epithelial cell line.We used unstimulated or IFN-γ-stimulated Caco-2 cells, as a model for homeostatic and inflamed gastrointestinal tracts, respectively. We investigated the effect of exogenous recombinant Nef on monolayer integrity analyzing its uptake, transepithelial electrical resistance, permeability to FITC-dextran and the expression of tight junction proteins. Moreover, we measured the induction of proinflammatory mediators. Exogenous Nef was taken up by Caco-2 cells, increased intestinal epithelial permeability and upset the IFN-γ-induced reduction of transepithelial resistance, interfering with tight junction protein expression. Moreover, Nef inhibited IFN-γ-induced apoptosis and up-regulated TNF-α, IL-6 and MIP-3α production by Caco-2 cells while down-regulated IL-10 production. The simultaneous exposure of Caco-2 cells to Nef and IFN-γ did not affect cytokine secretion respect to untreated cells. Finally, we found that Nef counteracted the IFN-γ induced arachidonic acid cascade.Our findings suggest that exogenous Nef, perturbing the IFN-γ-induced impairment of intestinal epithelial cells, could prolong cell survival, thus allowing for accumulation of viral particles. Our results may improve the understanding of AIDS pathogenesis, supporting the discovery of new therapeutic interventions.

Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water.

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Yang, Ji; Cao, Limei; Guo, Rui; Jia, Jinping

2010-12-15

Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m(2)g(-1), the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly. Copyright © 2010 Elsevier B.V. All rights reserved.

A calcite permeable reactive barrier for the remediation of Fluoride from spent potliner (SPL) contaminated groundwater

DEFF Research Database (Denmark)

Turner, B.D.; Binning, Philip John; Sloan, S.W.

2008-01-01

The use of calcite (CaCO3) as a substrate for a permeable reactive barrier (PRB) for removing fluoride from contaminated groundwater is proposed and is illustrated by application to groundwater contaminated by spent potliner leachate (SPL), a waste derived from the aluminium smelting process...... leachate indicate that the complex chemical matrix of the SPL leachate can impact fluoride removal significantly. For SPL contaminant mixtures, fluoride removal is initially less than expected from idealized, pure, solutions. However, with time, the effect of other contaminants on fluoride removal...... diminishes. Column tests also show that pH control is important for optimizing fluoride removal with the mass removed increasing with decreasing pH. Barrier pH can be regulated by CO2 addition with the point of injection being critical for optimising the remediation performance. Experimental and model...

Myosin light chain kinase knockout improves gut barrier function and confers a survival advantage in polymicrobial sepsis.

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Lorentz, C Adam; Liang, Zhe; Meng, Mei; Chen, Ching-Wen; Yoseph, Benyam P; Breed, Elise R; Mittal, Rohit; Klingensmith, Nathan J; Farris, Alton B; Burd, Eileen M; Koval, Michael; Ford, Mandy L; Coopersmith, Craig M

2017-06-07

Sepsis-induced intestinal hyperpermeability is mediated by disruption of the epithelial tight junction, which is closely associated with the peri-junctional actin-myosin ring. Myosin light chain kinase (MLCK) phosphorylates the myosin regulatory light chain, resulting in increased permeability. The purpose of this study was to determine whether genetic deletion of MLCK would alter gut barrier function and survival from sepsis. MLCK -/- and wild type (WT) mice were subjected to cecal ligation and puncture and assayed for both survival and mechanistic studies. Survival was significantly increased in MLCK -/- mice (95% vs. 24%, p<0.0001). Intestinal permeability increased in septic WT mice compared to unmanipulated mice. In contrast, permeability in septic MLCK -/- mice was similar to that seen in unmanipulated animals. Improved gut barrier function in MLCK -/- mice was associated with increases in the tight junction mediators ZO-1 and claudin 15 without alterations in claudin 1, 2, 3, 4, 5, 7, 8, 13, occludin or JAM-A. Other components of intestinal integrity (apoptosis, proliferation and villus length) were unaffected by MLCK deletion as were local peritoneal inflammation and distant lung injury. Systemic IL-10 was decreased greater than 10-fold in MLCK -/- mice; however, survival was similar between septic MLCK -/- mice given exogenous IL-10 or vehicle. These data demonstrate that deletion of MLCK improves survival following sepsis, associated with normalization of intestinal permeability and selected tight junction proteins.

Inflammatory Response and Barrier Dysfunction by Different e-Cigarette Flavoring Chemicals Identified by Gas Chromatography-Mass Spectrometry in e-Liquids and e-Vapors on Human Lung Epithelial Cells and Fibroblasts.

Science.gov (United States)

Gerloff, Janice; Sundar, Isaac K; Freter, Robert; Sekera, Emily R; Friedman, Alan E; Robinson, Risa; Pagano, Todd; Rahman, Irfan

2017-03-01

Recent studies suggest that electronic cigarette (e-cig) flavors can be harmful to lung tissue by imposing oxidative stress and inflammatory responses. The potential inflammatory response by lung epithelial cells and fibroblasts exposed to e-cig flavoring chemicals in addition to other risk-anticipated flavor enhancers inhaled by e-cig users is not known. The goal of this study was to evaluate the release of the proinflammatory cytokine (interleukin-8 [IL-8]) and epithelial barrier function in response to different e-cig flavoring chemicals identified in various e-cig e-liquid flavorings and vapors by chemical characterization using gas chromatography-mass spectrometry analysis. Flavorings, such as acetoin (butter), diacetyl, pentanedione, maltol (malt), ortho-vanillin (vanilla), coumarin, and cinnamaldehyde in comparison with tumor necrosis factor alpha (TNFα), were used in this study. Human bronchial epithelial cells (Beas2B), human mucoepidermoid carcinoma epithelial cells (H292), and human lung fibroblasts (HFL-1) were treated with each flavoring chemical for 24 hours. The cells and conditioned media were then collected and analyzed for toxicity (viability %), lung epithelial barrier function, and proinflammatory cytokine IL-8 release. Cell viability was not significantly affected by any of the flavoring chemicals tested at a concentration of 10 μM to 1 mM. Acetoin and diacetyl treatment induced IL-8 release in Beas2B cells. Acetoin- and pentanedione-treated HFL-1 cells produced a differential, but significant response for IL-8 release compared to controls and TNFα. Flavorings, such as ortho-vanillin and maltol, induced IL-8 release in Beas2B cells, but not in H292 cells. Of all the flavoring chemicals tested, acetoin and maltol were more potent inducers of IL-8 release than TNFα in Beas2B and HFL-1 cells. Flavoring chemicals rapidly impaired epithelial barrier function in human bronchial epithelial cells (16-HBE) as measured by electric cell surface

The epithelium in idiopathic pulmonary fibrosis: breaking the barrier

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Ana eCamelo

2014-01-01

Full Text Available Idiopathic pulmonary fibrosis is a progressive disease of unknown etiology characterised by a dysregulated wound healing response that leads to fatal accumulation of fibroblasts and extracellular matrix in the lung, which compromises tissue architecture and lung function capacity. Injury to type II alveolar epithelial cells is thought to be the key event for the initiation of the disease, and so far both genetic factors, such as mutations in telomerase and MUC5b genes as well as environmental components, like cigarette smoking, exposure to asbestos and viral infections have been implicated as potential initiating triggers. The injured epithelium then enters a state of senescence-associated secretory phenotype whereby it produces both pro-inflammatory and pro-fibrotic factors that contribute to the wound healing process in the lung. Immune cells, like macrophages and neutrophils as well as activated myofibroblasts then perpetuate this cascade of epithelial cell apoptosis and proliferation by release of pro-fibrotic TGF-β and continuous deposition of extracellular matrix stiffens the basement membrane, altogether having a deleterious impact on epithelial cell function. In this review we describe the role of the epithelium as both a physical and immunological barrier between environment and self in the homeostatic versus diseased lung and explore the potential mechanisms of epithelial cell injury and the impact of loss of epithelial cell permeability and function on cytokine production, inflammation and myofibroblast activation in the fibrotic lung.

Water permeability of acinar cell membranes in the isolated perfused rabbit mandibular salivary gland.

Science.gov (United States)

Steward, M C; Seo, Y; Rawlings, J M; Case, R M

1990-01-01

1. The diffusive water permeability of epithelial cell membranes in the perfused rabbit mandibular salivary gland was measured at 37 degrees C by a 1H nuclear magnetic resonance relaxation method using an extracellular relaxation reagent, gadolinium diethylenetriaminepentaacetic acid (Gd(DTPA)). 2. In glands perfused with a HEPES-buffered solution containing 10 mmol l-1 Gd(DTPA), the spin-lattice (T1) relaxation of the water protons showed two exponential components. The water compartment responsible for the slower component corresponded in magnitude to 71 +/- 5% of the wet weight of the gland, and was attributed to the exchangeable intracellular water of the acinar cells. 3. The rate constant for water efflux from the cells was estimated to be 4.1 +/- 0.1 s-1 which would be consistent with a diffusive membrane permeability (Pd) of approximately 3 x 10(-3) cm s-1. Stimulation with acetylcholine (10(-6) mol l-1) did not cause any detectable change in membrane water permeability. 4. Since the basolateral membrane probably provides the main pathway for water efflux, the osmotic water permeability of this barrier (expressed per gland) was estimated to be less than 6.2 cm3 s-1. This would be insufficient to account for the generation of a near-isosmotic fluid at the flow rates observed during secretion, and suggests that a substantial fraction of the flow of water occurs via a paracellular route. PMID:1966053

Excreted/secreted Trichuris suis products reduce barrier function and suppress inflammatory cytokine production of intestinal epithelial cells

DEFF Research Database (Denmark)

Hiemstra, I. H.; Klaver, E. J.; Vrijland, K.

2014-01-01

The administration of helminths is considered a promising strategy for the treatment of autoimmune diseases due to their immunomodulatory properties. Currently, the application of the helminth Trichuris suis as a treatment for Crohn's disease is being studied in large multi-center clinical trials....... The intestinal epithelium forms an efficient barrier between the intestinal lumen containing the microbial flora and helminths, and dendritic cells (DCs) present in the lamina propria that determine the TH response. Here, we investigated how excreted/secreted (E/S) products of T. suis affect the barrier function...... of intestinal epithelial cells (IECs) in order to reach the DCs and modulate the immune response. We show that T. suis E/S products reduce the barrier function and the expression of the tight junction proteins EMP-1 and claudin-4 in IEC CMT93/69 monolayers in a glycan-dependent manner. This resulted...

Integrated evaluation of the performance of a more than seven year old permeable reactive barrier at a site contaminated with chlorinated aliphatic hydrocarbons (CAHs)

DEFF Research Database (Denmark)

Muchitsch, Nanna; Nooten, Thomas Van; Bastiaens, Leen

2011-01-01

An important issue of concern for permeable reactive iron barriers is the long-term efficiency of the barriers due to the long operational periods required. Mineral precipitation resulting from the anaerobic corrosion of the iron filings and bacteria present in the barrier may play an important...... performed equally well as virgin granular iron of the same type based on determined degradation rates despite that parts of the cored iron material were covered by mineral precipitates (especially iron sulfides, carbonate green rust and aragonite). The PCR analysis performed on the iron core samples...

Remediation of groundwater contaminated with the lead-phenol binary system by granular dead anaerobic sludge-permeable reactive barrier.

Science.gov (United States)

Faisal, Ayad A H; Abd Ali, Ziad T

2017-10-01

Computer solutions (COMSOL) Multiphysics 3.5a software was used for simulating the one-dimensional equilibrium transport of the lead-phenol binary system including the sorption process through saturated sandy soil as the aquifer and granular dead anaerobic sludge (GDAS) as the permeable reactive barrier. Fourier-transform infrared spectroscopy analysis proved that the carboxylic and alcohol groups are responsible for the bio-sorption of lead onto GDAS, while phosphines, aromatic and alkane are the functional groups responsible for the bio-sorption of phenol. Batch tests have been performed to characterize the equilibrium sorption properties of the GDAS and sandy soil in lead and/or phenol containing aqueous solutions. Numerical and experimental results proved that the barrier plays a potential role in the restriction of the contaminant plume migration and there is a linear relationship between longevity and thickness of the barrier. A good agreement between these results was recognized with root mean squared error not exceeding 0.04.

Acoustic cavitation-based monitoring of the reversibility and permeability of ultrasound-induced blood-brain barrier opening.

Science.gov (United States)

Sun, Tao; Samiotaki, Gesthimani; Wang, Shutao; Acosta, Camilo; Chen, Cherry C; Konofagou, Elisa E

2015-12-07

Cavitation events seeded by microbubbles have been previously reported to be associated with MR- or fluorescent-contrast enhancement after focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening. However, it is still unknown whether bubble activity can be correlated with the reversibility (the duration of opening and the likelihood of safe reinstatement) and the permeability of opened BBB, which is critical for the clinical translation of using passive cavitation detection to monitor, predict and control the opening. In this study, the dependence of acoustic cavitation on the BBB opening duration, permeability coefficient and histological damage occurrence were thus investigated. Transcranial pulsed FUS at 1.5 MHz in the presence of systemically circulating microbubbles was applied in the mouse hippocampi (n  =  60). The stable and inertial cavitation activities were monitored during sonication. Contrast-enhanced MRI was performed immediately after sonication and every 24 h up to 6 d thereafter, to assess BBB opening, brain tissue permeability and potential edema. Histological evaluations were used to assess the occurrence of neurovascular damages. It was found that stable cavitation was well correlated with: (1) the duration of the BBB opening (r(2)  =  0.77); (2) the permeability of the opened BBB (r(2)  =  0.82); (3) the likelihood of safe opening (P  cavitation dose was correlated with the resulting BBB permeability (r(2)  =  0.72). Stable cavitation was found to be more reliable than inertial cavitation at assessing the BBB opening within the pressure range used in this study. This study demonstrates that the stable cavitation response during BBB opening holds promise for predicting and controlling the restoration and pharmacokinetics of FUS-opened BBB. The stable cavitation response therefore showed great promise in predicting the BBB opening duration, enabling thus control of opening according to the drug

Fluorescently labeled methyl-beta-cyclodextrin enters intestinal epithelial Caco-2 cells by fluid-phase endocytosis.

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Ferenc Fenyvesi

Full Text Available Cyclodextrins are widely used excipients for increasing the bioavailability of poorly water-soluble drugs. Their effect on drug absorption in the gastrointestinal tract is explained by their solubility- and permeability-enhancement. The aims of this study were to investigate penetration properties of fluorescently labeled randomly methylated-beta-cyclodextrin (FITC-RAMEB on Caco-2 cell layer and examine the cellular entry of cyclodextrins on intestinal cells. The permeability of FITC-RAMEB through Caco-2 monolayers was very limited. Using this compound in 0.05 mM concentration the permeability coefficient was 3.35±1.29×10(-8 cm/s and its permeability did not change in the presence of 5 mM randomly methylated-beta-cyclodextrin. Despite of the low permeability, cellular accumulation of FITC-RAMEB in cytoplasmic vesicles was significant and showed strong time and concentration dependence, similar to the characteristics of the macropinocytosis marker Lucifer Yellow. The internalization process was fully inhibited at 0°C and it was drastically reduced at 37°C applying rottlerin, an inhibitor of macropinocytosis. Notably, FITC-RAMEB colocalized with the early endosome organizer Rab5a. These results have revealed that FITC-RAMEB is able to enter intestinal epithelial cells by fluid-phase endocytosis from the apical side. This mechanism can be an additional process which helps to overcome the intestinal barrier and contributes to the bioavailability enhancement of cyclodextrins.

Taste Bud Labeling in Whole Tongue Epithelial Sheet in Adult Mice.

Science.gov (United States)

Venkatesan, Nandakumar; Boggs, Kristin; Liu, Hong-Xiang

2016-04-01

Molecular labeling in whole-mount tissues provides an efficient way to obtain general information about the formation, maintenance, degeneration, and regeneration of many organs and tissues. However, labeling of lingual taste buds in whole tongue tissues in adult mice has been problematic because of the strong permeability barrier of the tongue epithelium. In this study, we present a simple method for labeling taste buds in the intact tongue epithelial sheet of an adult mouse. Following intralingual protease injection and incubation, immediate fixation of the tongue on mandible in 4% paraformaldehyde enabled the in situ shape of the tongue epithelium to be well maintained after peeling. The peeled epithelium was accessible to taste bud labeling with a pan-taste cell marker, keratin 8, and a type II taste cell marker, α-gustducin, in all three types of taste papillae, that is, fungiform, foliate, and circumvallate. Overnight incubation of tongue epithelial sheets with primary and secondary antibodies was sufficient for intense labeling of taste buds with both fluorescent and DAB visualizations. Labeled individual taste buds were easy to identify and quantify. This protocol provides an efficient way for phenotypic analyses of taste buds, especially regarding distribution pattern and number.

Dietary Virgin Olive Oil Reduces Blood Brain Barrier Permeability, Brain Edema, and Brain Injury in Rats Subjected to Ischemia-Reperfusion

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Fatemeh Mohagheghi

2010-01-01

Full Text Available Recent studies suggest that dietary virgin olive oil (VOO reduces hypoxia-reoxygenation injury in rat brain slices. We sought to extend these observations in an in vivo study of rat cerebral ischemia-reperfusion injury. Four groups, each consisting of 18 Wistar rats, were studied. One group (control received saline, while three treatment groups received oral VOO (0.25, 0.5, and 0.75 mL/kg/day, respectively. After 30 days, blood lipid profiles were determined, before a 60-min period of middle cerebral artery occlusion (MCAO. After 24-h reperfusion, neurological deficit scores, infarct volume, brain edema, and blood brain barrier permeability were each assessed in subgroups of six animals drawn from each main group. VOO reduced the LDL/HDL ratio in doses of 0.25, 0.5, and 0.75 mL/kg/day in comparison to the control group (p < 0.05, and offered cerebroprotection from ischemia-reperfusion. For controls vs. doses of 0.25 vs. 0.5 vs. 0.75 mL/kg/day, attenuated corrected infarct volumes were 207.82 ± 34.29 vs. 206.41 ± 26.23 vs. 124.21 ± 14.73 vs. 108.46 ± 31.63 mm3; brain water content of the infarcted hemisphere was 82 ±± 0.25 vs. 81.5 ± 0.56 vs. 80.5 ± 0.22 vs. 80.5 ± 0.34%; and blood brain barrier permeability of the infarcted hemisphere was 11.31 ± 2.67 vs. 9.21 ± 2.28 vs. 5.83 ± 1.6 vs. 4.43 ± 0.93 µg/g tissue (p < 0.05 for measures in doses 0.5 and 0.75 mL/kg/day vs. controls. Oral administration of VOO reduces infarct volume, brain edema, blood brain barrier permeability, and improves neurologic deficit scores after transient MCAO in rats.

In vitro safety evaluation of human nasal epithelial cell monolayers exposed to carrageenan sinus wash.

Science.gov (United States)

Ramezanpour, Mahnaz; Murphy, Jae; Smith, Jason L P; Vreugde, Sarah; Psaltis, Alkis James

2017-12-01

Carrageenans have shown to reduce the viral load in nasal secretions and lower the incidence of secondary infections in children with common cold. Despite the widespread use of carrageenans in topical applications, the effect of carrageenans on the sinonasal epithelial barrier has not been elucidated. We investigate the effect of different carrageenans on the sinonasal epithelial barrier and inflammatory response in vitro. Iota and Kappa carrageenan delivered in saline irrigation solutions applied to air-liquid interface (ALI) cultures of primary human nasal epithelial cells from chronic rhinosinusitis patients and controls. Epithelial barrier structure was assessed by measuring the transepithelial electrical resistance (TEER) and immunolocalization of F actin. Ciliary beat frequency (CBF), toxicity, and inflammatory response was studied. Kappa or Iota carrageenan in the different solutions was not toxic, did not have detrimental effects on epithelial barrier structure and CBF. Rather, application of Kappa carrageenan significantly increased TEER and suppressed interleukin 6 (IL-6) secretion in ALI cultures from CRS patients. Kappa or Iota carrageenan solution was safe and did not negatively affect epithelial barrier function. Kappa carrageenan increased TEER and decreased IL-6 production in CRS patients, indicating positive effects on epithelial barrier function in vitro. © 2017 ARS-AAOA, LLC.

Dissociation of changes in the permeability of the blood-brain barrier from catecholamine-induced changes in blood pressure of normotensive and spontaneously hypertensive rats

International Nuclear Information System (INIS)

Sankar, R.; Domer, F.R.; Taylor, B.

1982-01-01

Researchers have studied the effects of the pressor catecholamine, dopamine, and the depressor catecholamine, isoproterenol, on the systemic blood pressure and the permeability of the blood-brain barrier (BBB) to albumin in normotensive (WKY) and spontaneously hypertensive (SHR) rats. The rats were anesthetized with pentobarbital. The permeability of the BBB to protein was measured by the extravasation of radioiodinated serum albumin (RISA). The permeability was decreased by both catecholamines despite the dose-dependent, yet opposite, changes in blood pressure in the WKY rats. The blood pressure response to both of the catecholamines was enhanced in the SHR rats. Isoproterenol caused a decrease in the permeability of the BBB in the SHR but dopamine did not. Results with both WKY and SHR rats are suggestive of an adrenergically-mediated decrease in movement across the BBB of compounds of large molecular weight, regardless of changes in blood pressure

Effects of hepatic ischemia-reperfusion injury on the blood-brain barrier permeability to [14C] and [13C]sucrose.

Science.gov (United States)

Miah, Mohammad K; Bickel, Ulrich; Mehvar, Reza

2017-12-01

Hepatic encephalopathy that is associated with severe liver failure may compromise the blood-brain barrier (BBB) integrity. However, the effects of less severe liver diseases, in the absence of overt encephalopathy, on the BBB are not well understood. The goal of the current study was to investigate the effects of hepatic ischemia-reperfusion (IR) injury on the BBB tight junction permeability to small, hydrophilic molecules using the widely used [ 14 C]sucrose and recently-proposed alternative [ 13 C]sucrose as markers. Rats were subjected to 20 min of hepatic ischemia or sham surgery, followed by 8 h of reperfusion before administration of a single bolus dose of [ 14 C] or [ 13 C]sucrose and collection of serial (0-30 min) blood and plasma and terminal brain samples. The concentrations of [ 14 C] and [ 13 C]sucrose in the samples were determined by measurement of total radioactivity (nonspecific) and LC-MS/MS (specific), respectively. IR injury significantly increased the blood, plasma, and brain concentrations of both [ 14 C] and [ 13 C]sucrose. However, when the brain concentrations were corrected for their respective area under the blood concentration-time curve, only [ 14 C]sucrose showed significantly higher (30%) BBB permeability values in the IR animals. Because [ 13 C]sucrose is a more specific BBB permeability marker, these data indicate that our animal model of hepatic IR injury does not affect the BBB tight junction permeability to small, hydrophilic molecules. Methodological differences among studies of the effects of liver diseases on the BBB permeability may confound the conclusions of such studies.

[Chromogranin A derived peptide CGA47-66 inhibits hyper-permeability of blood brain barrier in mice with sepsis].

Science.gov (United States)

Zeng, Yan; Zhang, Dan; Jiang, Liping; Wei, Fu; Xu, Shan

2016-02-01

To explore the effect of chromofungin (CHR), a chromogranin A (CGA) derived peptide CGA47-66, on hyper-permeability of blood brain barrier in septic mice. 120 healthy male C57BL/6 mice were randomly divided into groups, with 12 mice in each group. Seventy-two mice were used for dynamic observation of the contents of water and Evan blue (EB) in brain tissue after being treated with lipopolysaccharide (LPS). Another 48 mice were divided into normal saline control group (NS group), LPS induced sepsis model group (LPS group), low-dose CHR pretreatment group (CL+LPS group), and high-dose CHR pretreatment group (CH+LPS group). The septic model was reproduced by intraperitoneal injection of 10 mg/kg LPS 0.1 mL, and the mice in NS group was given equal volume of normal saline. The mice in CL+LPS group and CH+LPS group were intraperitoneally injected with 15.5 μg/kg and 77.5 μg/kg CHR 10 minutes before LPS injection. Six hours after LPS injection, 4 mL/kg of 2% EB was injected via caudal vein, the contents of water and EB in brain tissue were determined, and EB immune fluorescence in brain tissue was determined to assess the changes in permeability of blood brain barrier. Brain pathology was observed with hematoxylin and eosin (HE) staining. With the extension of time after LPS injection, the contents of water and EB in brain tissue were gradually increased, and the time of difference with statistical significance appeared earlier when compared with that of control group in the contents of water than that in EB contents (3 hours and 6 hours, respectively). The contents of water and EB in brain tissue in LPS group were significantly increased as compared with NS group [water content: (79.77±0.62)% vs. (78.28±0.44)%, P water and EB contents in brain tissue induced by LPS, and the effect was more significant in CH+LPS group [water content: (78.15±0.73)% vs. (79.77±0.62)%, EB (μg/g): 7.09±2.59 vs. 13.87±4.50, both P leakage in LPS group was more marked than that of NS

IL-22 Upregulates Epithelial Claudin-2 to Drive Diarrhea and Enteric Pathogen Clearance.

Science.gov (United States)

Tsai, Pei-Yun; Zhang, Bingkun; He, Wei-Qi; Zha, Juan-Min; Odenwald, Matthew A; Singh, Gurminder; Tamura, Atsushi; Shen, Le; Sailer, Anne; Yeruva, Sunil; Kuo, Wei-Ting; Fu, Yang-Xin; Tsukita, Sachiko; Turner, Jerrold R

2017-06-14

Diarrhea is a host response to enteric pathogens, but its impact on pathogenesis remains poorly defined. By infecting mice with the attaching and effacing bacteria Citrobacter rodentium, we defined the mechanisms and contributions of diarrhea and intestinal barrier loss to host defense. Increased permeability occurred within 2 days of infection and coincided with IL-22-dependent upregulation of the epithelial tight junction protein claudin-2. Permeability increases were limited to small molecules, as expected for the paracellular water and Na + channel formed by claudin-2. Relative to wild-type, claudin-2-deficient mice experienced severe disease, including increased mucosal colonization by C. rodentium, prolonged pathogen shedding, exaggerated cytokine responses, and greater tissue injury. Conversely, transgenic claudin-2 overexpression reduced disease severity. Chemically induced osmotic diarrhea reduced colitis severity and C. rodentium burden in claudin-2-deficient, but not transgenic, mice, demonstrating that claudin-2-mediated protection is the result of enhanced water efflux. Thus, IL-22-induced claudin-2 upregulation drives diarrhea and pathogen clearance. Copyright © 2017 Elsevier Inc. All rights reserved.

MiR-144 Increases Intestinal Permeability in IBS-D Rats by Targeting OCLN and ZO1

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Qiuke Hou

2017-12-01

Full Text Available Background/Aims: Irritable bowel syndrome with diarrhoea (IBS-D is a chronic, functional bowel disorder characterized by abdominal pain or diarrhoea and altered bowel habits, which correlate with intestinal hyperpermeability. MicroRNAs (miRNAs are involved in regulating intestinal permeability in IBS-D. However, the role of miRNAs in regulating intestinal permeability and protecting the epithelial barrier remains unclear. Our goals were to (i identify differential expression of miRNAs and their targets in the distal colon of IBS-D rats; (ii verify in vitro whether occludin (OCLN and zonula occludens 1 (ZO1/TJP1 were direct targets of miR-144 and were down-regulated in IBS-D rats; and (iii determine whether down-regulation of miR-144 in vitro could reverse the pathological hallmarks of intestinal hyperpermeability via targeting OCLN and ZO1. Methods: The IBS-D rat model was established using 4% acetic acid and evaluated by haematoxylin-eosin (HE staining. The distal colon was obtained in order to perform miRNA microarray analysis and to isolate and culture colonic epithelial cells. When differential expression of miRNA was found, the results were verified by qRT-PCR, and the target genes were further explored by bioinformatics analysis. Correlation analyses were carried out to compare the expression of miRNA and target genes. Then, mutants, miRNA mimics and inhibitors of the target genes were constructed and transfected to colonic epithelial cells. qRT-PCR, western blotting, enzyme-linked immunosorbent assays (ELISAs and dual-luciferase assays were used to investigate the expression of miR-144 and OCLN, ZO1 in IBS-D rats. Results: There were 8 up-regulated and 18 down-regulated miRNAs identified in the IBS-D rat model. Of these, miR-144 was markedly up-regulated and resulted in the down-regulation of OCLN and ZO1 expression. Overexpression of miR-144 by transfection of miR-144 precursor markedly inhibited the expression of OCLN and ZO1. Further

Analytical model for the design of in situ horizontal permeable reactive barriers (HPRBs) for the mitigation of chlorinated solvent vapors in the unsaturated zone

NARCIS (Netherlands)

Verginelli, Iason; Capobianco, Oriana; Hartog, Niels; Baciocchi, Renato

In this work we introduce a 1-D analytical solution that can be used for the design of horizontal permeable reactive barriers (HPRBs) as a vapor mitigation system at sites contaminated by chlorinated solvents. The developed model incorporates a transient diffusion-dominated transport with a

Reducing small intestinal permeability attenuates colitis in the IL10 gene-deficient mouse

Science.gov (United States)

Arrieta, M C; Madsen, K; Doyle, J; Meddings, J

2008-01-01

Background: Defects in the small intestinal epithelial barrier have been associated with inflammatory bowel disease but their role in the causation of disease is still a matter of debate. In some models of disease increased permeability appears to be a very early event. The interleukin 10 (IL10) gene-deficient mouse spontaneously develops colitis after 12 weeks of age. These mice have been shown to have increased small intestinal permeability that appears early in life. Furthermore, the development of colitis is dependent upon luminal agents, as animals do not develop disease if raised under germ-free conditions. Aims: To determine if the elevated small bowel permeability can be prevented, and if by doing so colonic disease is prevented or attenuated. Methods: IL10 gene-deficient (IL10−/−) mice) were treated with AT-1001 (a zonulin peptide inhibitor), a small peptide previously demonstrated to reduce small intestinal permeability. Small intestinal permeability was measured, in vivo, weekly from 4 to 17 weeks of age. Colonic disease was assessed at 8 weeks in Ussing chambers, and at 17 weeks of age inflammatory cytokines and myeloperoxidase were measured in the colon. Colonic permeability and histology were also endpoints. Results: Treated animals showed a marked reduction in small intestinal permeability. Average area under the lactulose/mannitol time curve: 5.36 (SE 0.08) in controls vs 3.97 (SE 0.07) in the high-dose AT-1001 group, p<0.05. At 8 weeks of age there was a significant reduction of colonic mucosal permeability and increased electrical resistance. By 17 weeks of age, secretion of tumour necrosis factor α (TNFα) from a colonic explant was significantly lower in the treated group (25.33 (SE 4.30) pg/mg vs 106.93 (SE 17.51) pg/ml in controls, p<0.01). All other markers also demonstrated a clear reduction of colitis in the treated animals. Additional experiments were performed which demonstrated that AT-1001 was functionally active only in the small

Zero-Valent Iron Permeable Reactive Barriers: A Review of Performance

International Nuclear Information System (INIS)

Korte, NE

2001-01-01

This report briefly reviews issues regarding the implementation of the zero-valent iron permeable reactive barrier (PRB) technology at sites managed by the U.S. Department of Energy (DOE). Initially, the PRB technology, using zero-valent iron for the reactive media, was received with great enthusiasm, and DOE invested millions of dollars testing and implementing PRBs. Recently, a negative perception of the technology has been building. This perception is based on the failure of some deployments to satisfy goals for treatment and operating expenses. The purpose of this report, therefore, is to suggest reasons for the problems that have been encountered and to recommend whether DOE should invest in additional research and deployments. The principal conclusion of this review is that the most significant problems have been the result of insufficient characterization, which resulted in poor engineering implementation. Although there are legitimate concerns regarding the longevity of the reactive media, the ability of zero-valent iron to reduce certain chlorinated hydrocarbons and to immobilize certain metals and radionuclides is well documented. The primary problem encountered at some DOE full-scale deployments has been an inadequate assessment of site hydrology, which resulted in misapplication of the technology. The result is PRBs with higher than expected flow velocities and/or incomplete plume capture

Type 3 innate lymphoid cells maintain intestinal epithelial stem cells after tissue damage

NARCIS (Netherlands)

P. Aparicio-Domingo (Patricia); M. Romera Hernández (Mónica); J.J. Karrich (Julien J.); F.H.J. Cornelissen (Ferry); N. Papazian (Natalie); D.J. Lindenbergh-Kortleve (Dicky); J.A. Butler (James A.); L. Boon (Louis); M. Coles (Mark); J.N. Samsom (Janneke); T. Cupedo (Tom)

2015-01-01

textabstractDisruption of the intestinal epithelial barrier allows bacterial translocation and predisposes to destructive inflammation. To ensure proper barrier composition, crypt-residing stem cells continuously proliferate and replenish all intestinal epithelial cells within days. As a consequence

The Effector Domain Region of the Vibrio vulnificus MARTX Toxin Confers Biphasic Epithelial Barrier Disruption and Is Essential for Systemic Spread from the Intestine.

Directory of Open Access Journals (Sweden)

Hannah E Gavin

2017-01-01

Full Text Available Vibrio vulnificus causes highly lethal bacterial infections in which the Multifunctional Autoprocessing Repeats-in-Toxins (MARTX toxin product of the rtxA1 gene is a key virulence factor. MARTX toxins are secreted proteins up to 5208 amino acids in size. Conserved MARTX N- and C-terminal repeat regions work in concert to form pores in eukaryotic cell membranes, through which the toxin's central region of modular effector domains is translocated. Upon inositol hexakisphosphate-induced activation of the of the MARTX cysteine protease domain (CPD in the eukaryotic cytosol, effector domains are released from the holotoxin by autoproteolytic activity. We previously reported that the native MARTX toxin effector domain repertoire is dispensable for epithelial cellular necrosis in vitro, but essential for cell rounding and apoptosis prior to necrotic cell death. Here we use an intragastric mouse model to demonstrate that the effector domain region is required for bacterial virulence during intragastric infection. The MARTX effector domain region is essential for bacterial dissemination from the intestine, but dissemination occurs in the absence of overt intestinal tissue pathology. We employ an in vitro model of V. vulnificus interaction with polarized colonic epithelial cells to show that the MARTX effector domain region induces rapid intestinal barrier dysfunction and increased paracellular permeability prior to onset of cell lysis. Together, these results negate the inherent assumption that observations of necrosis in vitro directly predict bacterial virulence, and indicate a paradigm shift in our conceptual understanding of MARTX toxin function during intestinal infection. Results implicate the MARTX effector domain region in mediating early bacterial dissemination from the intestine to distal organs-a key step in V. vulnificus foodborne pathogenesis-even before onset of overt intestinal pathology.

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to flaxseed oil and vitamin E and maintenance of the skin permeability barrier function pursuant to Article 13(5) of Regulation (EC) No 1924/2006

DEFF Research Database (Denmark)

Tetens, Inge

related to a combination of flaxseed oil and vitamin E and maintenance of the skin permeability barrier function. The food constituent that is the subject of the health claim is a combination of flaxseed oil and vitamin E. The Panel considers that the combination of flaxseed oil and vitamin E...... be drawn from these studies for the scientific substantiation of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of flaxseed oil and vitamin E and maintenance of the skin permeability barrier function...... is sufficiently characterised. The claimed effect is “contributes to maintain skin permeability barrier function”. The target population proposed by the applicant is healthy adults with dry and sensitive skin. Maintenance of the permeability barrier function of the skin is a beneficial physiological effect...

[Removal of nitrate from groundwater using permeable reactive barrier].

Science.gov (United States)

Li, Xiu-Li; Yang, Jun-Jun; Lu, Xiao-Xia; Zhang, Shu; Hou, Zhen

2013-03-01

To provide a cost-effective method for the remediation of nitrate-polluted groundwater, column experiments were performed to study the removal of nitrate by permeable reactive barrier filled with fermented mulch and sand (biowall), and the mechanisms and influence factors were explored. The experimental results showed that the environmental condition in the simulated biowall became highly reduced after three days of operation (oxidation-reduction potential was below - 100 mV), which was favorable for the reduction of nitrate. During the 15 days of operation, the removal rate of nitrate nitrogen (NO3(-) -N) by the simulated biowall was 80%-90% (NO3(-)-N was reduced from 20 mg x L(-1) in the inlet water to 1.6 mg x L(-1) in the outlet water); the concentration of nitrite nitrogen (NO2(-) -N) in the outlet water was below 2.5 mg x L(-1); the concentration of ammonium nitrogen (NH4(+) -N) was low in the first two days but increased to about 12 mg x L(-1) since day three. The major mechanisms involved in the removal of nitrate nitrogen were adsorption and biodegradation. When increasing the water flow velocity in the simulated biowall, the removal rate of NO3(-) -N was reduced and the concentration of NH4(+) -N in the outlet water was significantly reduced. A simulated zeolite wall was set up following the simulated biowall and 98% of the NH4(+) -N could be removed from the water.

An in vitro transport model for rapid screening and predicting the permeability of candidate compounds at blood-brain barrier.

Science.gov (United States)

Yang, Zhi-Hong; Sun, Xiao; Mei, Chao; Sun, Xiao-Bo; Liu, Xiao-Dong; Chang, Qi

2011-12-01

The aim of this study was to design and develop a simple in vitro blood-brain barrier (BBB) permeation model for elementarily and rapidly predicting the permeability of candidate compounds at BBB and further evaluating whether P-glycoprotein (P-gp) affects them across BBB. The model was mainly composed of cultured rat brain microvascular endothelial cells (rBMECs), glass contraption, and micropore membrane. First, we evaluated the model by morphological observation. Second, the restriction effects of paracellular transport were verified by measuring marker probes transport, and monitoring transendothelial electrical resistance (TEER) and leakage. Finally, protein expression and activity of P-gp were confirmed by carrying out Western blot analysis and polarized transport of rhodamine-123 (Rho123) in rBMECs. The rBMECs retained both endothelial cells and BBB features. The rBMECs model reproducibly attained approximately 130 Ω cm² on the steady-state TEER value, and displayed a barrier function to marker probes transport by decreasing the permeability. Protein band of 170 kDa manifested the existence of P-gp in the rBMECs, and the findings of cyclosporin A-sensitive decrease of Rho123 efflux confirmed the presence of P-gp activity. A simple, rapid, and convenient in vitro BBB permeation model was successfully established and applied to evaluate the BBB transport profiles of three natural flavonoids: quercetin, naringenin, and rutin.

Current progress in the permeability and its enhancement approches for TCM active ingredients across blood-eye barrier

Directory of Open Access Journals (Sweden)

Yu-Yang Bai

2014-10-01

Full Text Available Blood-eye barrier(BEBis one of the most important structures of organism to maintain homeostasis of the eye. However, it is the major constraint for the medication of intraocular diseases. Traditional Chinese medicines have distinctive advantages for the treatment of intraocular diseases, which can be used to regulate the physiological function of human body with low toxicity. In this article, we have briefly summarized the feature of BEB, with the domestic and foreign literatures combined, and mainly reviewed current progress in the field of study on the permeability of traditional Chinese medicines and effective components in BEB and promoting methods.

Acoustic cavitation-based monitoring of the reversibility and permeability of ultrasound-induced blood-brain barrier opening

International Nuclear Information System (INIS)

Sun, Tao; Samiotaki, Gesthimani; Wang, Shutao; Acosta, Camilo; Chen, Cherry C; Konofagou, Elisa E

2015-01-01

Cavitation events seeded by microbubbles have been previously reported to be associated with MR- or fluorescent-contrast enhancement after focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening. However, it is still unknown whether bubble activity can be correlated with the reversibility (the duration of opening and the likelihood of safe reinstatement) and the permeability of opened BBB, which is critical for the clinical translation of using passive cavitation detection to monitor, predict and control the opening. In this study, the dependence of acoustic cavitation on the BBB opening duration, permeability coefficient and histological damage occurrence were thus investigated. Transcranial pulsed FUS at 1.5 MHz in the presence of systemically circulating microbubbles was applied in the mouse hippocampi (n  =  60). The stable and inertial cavitation activities were monitored during sonication. Contrast-enhanced MRI was performed immediately after sonication and every 24 h up to 6 d thereafter, to assess BBB opening, brain tissue permeability and potential edema. Histological evaluations were used to assess the occurrence of neurovascular damages. It was found that stable cavitation was well correlated with: (1) the duration of the BBB opening (r 2   =  0.77); (2) the permeability of the opened BBB (r 2   =  0.82); (3) the likelihood of safe opening (P  <  0.05, safe opening compared to cases of damage; P  <  0.0001, no opening compared to safe opening). The inertial cavitation dose was correlated with the resulting BBB permeability (r 2   =  0.72). Stable cavitation was found to be more reliable than inertial cavitation at assessing the BBB opening within the pressure range used in this study. This study demonstrates that the stable cavitation response during BBB opening holds promise for predicting and controlling the restoration and pharmacokinetics of FUS-opened BBB. The stable cavitation response

Acoustic cavitation-based monitoring of the reversibility and permeability of ultrasound-induced blood-brain barrier opening

Science.gov (United States)

Sun, Tao; Samiotaki, Gesthimani; Wang, Shutao; Acosta, Camilo; Chen, Cherry C.; Konofagou, Elisa E.

2015-12-01

Cavitation events seeded by microbubbles have been previously reported to be associated with MR- or fluorescent-contrast enhancement after focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening. However, it is still unknown whether bubble activity can be correlated with the reversibility (the duration of opening and the likelihood of safe reinstatement) and the permeability of opened BBB, which is critical for the clinical translation of using passive cavitation detection to monitor, predict and control the opening. In this study, the dependence of acoustic cavitation on the BBB opening duration, permeability coefficient and histological damage occurrence were thus investigated. Transcranial pulsed FUS at 1.5 MHz in the presence of systemically circulating microbubbles was applied in the mouse hippocampi (n  =  60). The stable and inertial cavitation activities were monitored during sonication. Contrast-enhanced MRI was performed immediately after sonication and every 24 h up to 6 d thereafter, to assess BBB opening, brain tissue permeability and potential edema. Histological evaluations were used to assess the occurrence of neurovascular damages. It was found that stable cavitation was well correlated with: (1) the duration of the BBB opening (r2  =  0.77) (2) the permeability of the opened BBB (r2  =  0.82) (3) the likelihood of safe opening (P  cases of damage; P  <  0.0001, no opening compared to safe opening). The inertial cavitation dose was correlated with the resulting BBB permeability (r2  =  0.72). Stable cavitation was found to be more reliable than inertial cavitation at assessing the BBB opening within the pressure range used in this study. This study demonstrates that the stable cavitation response during BBB opening holds promise for predicting and controlling the restoration and pharmacokinetics of FUS-opened BBB. The stable cavitation response therefore showed great promise in predicting the

Measurement of brain perfusion, blood volume, and blood-brain barrier permeability, using dynamic contrast-enhanced T(1)-weighted MRI at 3 tesla

DEFF Research Database (Denmark)

Larsson, Henrik B W; Courivaud, Frédéric; Rostrup, Egill

2009-01-01

Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... on a pixel-by-pixel basis of cerebral perfusion, cerebral blood volume, and blood-brain barrier permeability.......Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model-free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 +/- 16/30 +/- 8/56 +/- 45 mL/100 g...

A subset of neurons controls the permeability of the peritrophic matrix and midgut structure in Drosophila adults.

Science.gov (United States)

Kenmoku, Hiroyuki; Ishikawa, Hiroki; Ote, Manabu; Kuraishi, Takayuki; Kurata, Shoichiro

2016-08-01

The metazoan gut performs multiple physiological functions, including digestion and absorption of nutrients, and also serves as a physical and chemical barrier against ingested pathogens and abrasive particles. Maintenance of these functions and structures is partly controlled by the nervous system, yet the precise roles and mechanisms of the neural control of gut integrity remain to be clarified in Drosophila Here, we screened for GAL4 enhancer-trap strains and labeled a specific subsets of neurons, using Kir2.1 to inhibit their activity. We identified an NP3253 line that is susceptible to oral infection by Gram-negative bacteria. The subset of neurons driven by the NP3253 line includes some of the enteric neurons innervating the anterior midgut, and these flies have a disorganized proventricular structure with high permeability of the peritrophic matrix and epithelial barrier. The findings of the present study indicate that neural control is crucial for maintaining the barrier function of the gut, and provide a route for genetic dissection of the complex brain-gut axis in adults of the model organism Drosophila. © 2016. Published by The Company of Biologists Ltd.

Lipopolysaccharide precipitates hepatic encephalopathy and increases blood-brain barrier permeability in mice with acute liver failure.

Science.gov (United States)

Chastre, Anne; Bélanger, Mireille; Nguyen, Bich N; Butterworth, Roger F

2014-03-01

Acute liver failure (ALF) is frequently complicated by infection leading to precipitation of central nervous system complications such as hepatic encephalopathy (HE) and increased mortality. There is evidence to suggest that when infection occurs in ALF patients, the resulting pro-inflammatory mechanisms may be amplified that could, in turn, have a major impact on blood-brain barrier (BBB) function. The aim of this study was to investigate the role of endotoxemia on the progression of encephalopathy in relation to BBB permeability during ALF. Adult male C57-BL6 mice with ALF resulting from azoxymethane-induced toxic liver injury were administered trace amounts of the endotoxin component lipopolysaccharide (LPS). Effects on the magnitude of the systemic inflammatory response, liver pathology and BBB integrity were measured as a function of progression of HE, defined as time to loss of corneal reflex (coma). Lipopolysaccharide caused additional two- to seven-fold (P liver pathology and associated increases of circulating transaminases as well as increased hyperammonaemia consistent with a further loss of viable hepatocytes. LPS treatment of ALF mice led to a rapid precipitation of hepatic coma and the BBB became permeable to the 25-kDa protein immunoglobulin G (IgG). This extravasation of IgG was accompanied by ignificant up-regulation of matrix metalloproteinase-9 (MMP-9), an endopeptidase known to modulate opening of the BBB in a wide range of neurological disorders. These findings represent the first direct evidence of inflammation-related BBB permeability changes in ALF. © 2013 John Wiley & Sons A/S. Publishing by John Wiley & Sons Ltd.

Oxcarbazepine-loaded polymeric nanoparticles: development and permeability studies across in vitro models of the blood-brain barrier and human placental trophoblast.

Science.gov (United States)

Lopalco, Antonio; Ali, Hazem; Denora, Nunzio; Rytting, Erik

2015-01-01

Encapsulation of antiepileptic drugs (AEDs) into nanoparticles may offer promise for treating pregnant women with epilepsy by improving brain delivery and limiting the transplacental permeability of AEDs to avoid fetal exposure and its consequent undesirable adverse effects. Oxcarbazepine-loaded nanoparticles were prepared by a modified solvent displacement method from biocompatible polymers (poly(lactic-co-glycolic acid) [PLGA] with or without surfactant and PEGylated PLGA [Resomer(®) RGPd5055]). The physical properties of the developed nanoparticles were determined with subsequent evaluation of their permeability across in vitro models of the blood-brain barrier (hCMEC/D3 cells) and human placental trophoblast cells (BeWo b30 cells). Oxcarbazepine-loaded nanoparticles with encapsulation efficiency above 69% were prepared with sizes ranging from 140-170 nm, polydispersity indices below 0.3, and zeta potential values below -34 mV. Differential scanning calorimetry and X-ray diffraction studies confirmed the amorphous state of the nanoencapsulated drug. The apparent permeability (Pe ) values of the free and nanoencapsulated oxcarbazepine were comparable across both cell types, likely due to rapid drug release kinetics. Transport studies using fluorescently-labeled nanoparticles (loaded with coumarin-6) demonstrated increased permeability of surfactant-coated nanoparticles. Future developments in enzyme-prodrug therapy and targeted delivery are expected to provide improved options for pregnant patients with epilepsy.

Effects of casein glycomacropeptide supplementation on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses in Escherichia coli K88 challenged piglets

Directory of Open Access Journals (Sweden)

Yili Rong

2015-06-01

Full Text Available Casein glycomacropeptide (CGMP is a bioactive peptide derived from milk with multiple functions. This study was aimed at evaluating the effects of CGMP as a potential feed additive on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses of Escherichia coli K88 (E. coli K88 challenged piglets. Eighteen weaning piglets were randomly assigned to three groups. Control group and K88 challenged group received a basal diet, and CGMP treated group received the basal diet supplemented with 1% of CGMP powder. The trail lasted for 12 days, K88 was orally administered to the piglets of K88 challenged group and CGMP treated group on days 8–10. The results showed that the diet containing 1% CGMP significantly alleviated the decrease in average daily gain (P  0.05 and barrier permeability damage (P < 0.05, and acute inflammatory response (P < 0.05 induced by E. coli K88 infection. In conclusion, CGMP supplementation in the diet protected the weaning piglets against E. coli K88 infection.

Epithelial cell-cell junctions and plasma membrane domains

NARCIS (Netherlands)

Giepmans, Ben N. G.; van Ijzendoorn, Sven C. D.

Epithelial cells form a barrier against the environment, but are also required for the regulated exchange of molecules between an organism and its surroundings. Epithelial cells are characterised by a remarkable polarization of their plasma membrane, evidenced by the appearance of structurally,

Permeability of PEGylated immunoarsonoliposomes through in vitro blood brain barrier-medulloblastoma co-culture models for brain tumor therapy.

Science.gov (United States)

Al-Shehri, Abdulghani; Favretto, Marco E; Ioannou, Panayiotis V; Romero, Ignacio A; Couraud, Pierre-Olivier; Weksler, Babette Barbash; Parker, Terry L; Kallinteri, Paraskevi

2015-03-01

Owing to restricted access of pharmacological agents into the brain due to blood brain barrier (BBB) there is a need: 1. to develop a more representative 3-D-co-culture model of tumor-BBB interaction to investigate drug and nanoparticle transport into the brain for diagnostic and therapeutic evaluation. 2. to address the lack of new alternative methods to animal testing according to replacement-reduction-refinement principles. In this work, in vitro BBB-medulloblastoma 3-D-co-culture models were established using immortalized human primary brain endothelial cells (hCMEC/D3). hCMEC/D3 cells were cultured in presence and in absence of two human medulloblastoma cell lines on Transwell membranes. In vitro models were characterized for BBB formation, zonula occludens-1 expression and permeability to dextran. Transferrin receptors (Tfr) expressed on hCMEC/D3 were exploited to facilitate arsonoliposome (ARL) permeability through the BBB to the tumor by covalently attaching an antibody specific to human Tfr. The effect of anticancer ARLs on hCMEC/D3 was assessed. In vitro BBB and BBB-tumor co-culture models were established successfully. BBB permeability was affected by the presence of tumor aggregates as suggested by increased permeability of ARLs. There was a 6-fold and 8-fold increase in anti-Tfr-ARL uptake into VC312R and BBB-DAOY co-culture models, respectively, compared to plain ARLs. The three-dimensional models might be appropriate models to study the transport of various drugs and nanocarriers (liposomes and immunoarsonoliposomes) through the healthy and diseased BBB. The immunoarsonoliposomes can be potentially used as anticancer agents due to good tolerance of the in vitro BBB model to their toxic effect.

Study on the application of permeable reactive barriers for remediation of uranium mine pit water

International Nuclear Information System (INIS)

Li Na'na; Zhu Yucheng

2012-01-01

Permeable reactive barrier (PRB) is economical and convenient on in suit remediation of polluted groundwater. In this paper, according to characteristics of uranium mine pit water, laboratory-scale PRB reactors were designed with the mixture of valent iron, active carbon, hydrated lime and quartz sands as reaction media. The feasibility and effectiveness of treating uranium mine pit water by PRB were tested under 3 different proportions of contaminants through dynamic simulation tests, which came out the optimal proportion of contaminants. The result indicated that the remediation effect of reactor B was the best, whose average removal rate to U was up to 99%. The quality of effluent attained the relevant standards, which indicated that the PRB technology is a feasible method for the treatment of uranium mine pit water. (authors)

Safety, efficacy, and molecular mechanism of claudin-1-specific peptides to enhance blood-nerve-barrier permeability.

Science.gov (United States)

Sauer, Reine-Solange; Krug, Susanne M; Hackel, Dagmar; Staat, Christian; Konasin, Natalia; Yang, Shaobing; Niedermirtl, Benedikt; Bosten, Judith; Günther, Ramona; Dabrowski, Sebastian; Doppler, Kathrin; Sommer, Claudia; Blasig, Ingolf E; Brack, Alexander; Rittner, Heike L

2014-07-10

The blood-nerve barrier consists of the perineurium and endoneurial vessels. The perineurial barrier is composed of a basal membrane and a layer of perineurial cells sealed by tight junction proteins preventing e.g. application of analgesics for selective regional pain control. One of the barrier-sealing proteins in the blood-nerve barrier is claudin-1. Therefore, the claudin-1-peptidomimetics (C1C2), derived from the first extracellular loop (ECL1) on claudin-1 was developed. In this study, we further evaluated the expression of tight junction proteins in the perineurium in Wistar rats and characterized the specificity, in vivo applicability, mechanism of action as well as the biocompatibility of C1C2. In the perineurium, claudin-19, tricellulin and ZO-1, but no claudin-2, 3, 8 and -11 were expressed. C1C2 specifically bound to the ECL1 of claudin-1 and fluorescent 5,6-carboxytetramethylrhodamine-C1C2 was rapidly internalized. Opening the perineurium with C1C2 reduced the mRNA and protein expression of claudin-1 and increased small and macromolecule permeability into the peripheral nerve. Application of C1C2 facilitated regional analgesia using μ-opioid receptor agonists like DAMGO or morphine without motor impairment in naïve rats as well as rats with hind paw inflammation. In contrast the control peptide C2C2 derived from ECL1 on claudin-2 did neither open the barrier nor facilitated opioid-mediated regional analgesia. C1C2 delivery was well tolerated and caused no morphological and functional nerve damage. C1C2 effects could be reversed by interference with the wnt-signal-transduction pathway, specifically the homeobox transcription factor cdx2, using a glycogen-synthase-kinase-3 inhibitor. In summary, we describe the composition of and a pathway to open the perineurial barrier employing a peptide to deliver hydrophilic substances to the peripheral nerve. Copyright © 2014 Elsevier B.V. All rights reserved.

Use of a permeable biological reaction barrier for groundwater remediation at a uranium mill tailings remedial action (UMTRA) site

International Nuclear Information System (INIS)

Thombre, M.S.; Thomson, B.M.; Barton, L.L.

1997-01-01

Previous work at the University of New Mexico and elsewhere has shown that sulfate reducing bacteria are capable of reducing uranium from the soluble +6 oxidation state to the insoluble +4 oxidation state. This chemistry forms the basis of a proposed groundwater remediation strategy in which microbial reduction would be used to immobilize soluble uranium. One such system would consist of a subsurface permeable barrier which would stimulate microbial growth resulting in the reduction of sulfate and nitrate and immobilization of metals while permitting the unhindered flow of ground water through it. This research investigated some of the engineering considerations associated with a microbial reducing barrier such as identifying an appropriate biological substrate, estimating the rate of substrate utilization, and identifying the final fate of the contaminants concentrated in the barrier matrix. The performance of batch reactors and column systems that treated simulated plume water was evaluated using cellulose, wheat straw, alfalfa hay, sawdust, and soluble starch as substrates. The concentrations of sulfate, nitrate, and U(VI) were monitored over time. Precipitates from each system were collected and the precipitated U(IV) was determined to be crystalline UO 2 (s) by X-ray Diffraction. The results of this study support the proposed use of cellulosic substrates as candidate barrier materials

Permeability of endothelial and astrocyte cocultures: in vitro blood-brain barrier models for drug delivery studies.

Science.gov (United States)

Li, Guanglei; Simon, Melissa J; Cancel, Limary M; Shi, Zhong-Dong; Ji, Xinying; Tarbell, John M; Morrison, Barclay; Fu, Bingmei M

2010-08-01

The blood-brain barrier (BBB) is a major obstacle for drug delivery to the brain. To seek for in vitro BBB models that are more accessible than animals for investigating drug transport across the BBB, we compared four in vitro cultured cell models: endothelial monoculture (bEnd3 cell line), coculture of bEnd3 and primary rat astrocytes (coculture), coculture with collagen type I and IV mixture, and coculture with Matrigel. The expression of the BBB tight junction proteins in these in vitro models was assessed using RT-PCR and immunofluorescence. We also quantified the hydraulic conductivity (L (p)), transendothelial electrical resistance (TER) and diffusive solute permeability (P) of these models to three solutes: TAMRA, Dextran 10K and Dextran 70K. Our results show that L (p) and P of the endothelial monoculture and coculture models are not different from each other. Compared with in vivo permeability data from rat pial microvessels, P of the endothelial monoculture and coculture models are not significantly different from in vivo data for Dextran 70K, but they are 2-4 times higher for TAMRA and Dextran 10K. This suggests that the endothelial monoculture and all of the coculture models are fairly good models for studying the transport of relatively large solutes across the BBB.

The intestinal barrier in irritable bowel syndrome: subtype-specific effects of the systemic compartment in an in vitro model.

Directory of Open Access Journals (Sweden)

Samefko Ludidi

Full Text Available Irritable bowel syndrome (IBS is a disorder with multifactorial pathophysiology. Intestinal barrier may be altered, especially in diarrhea-predominant IBS (IBS-D. Several mediators may contribute to increased intestinal permeability in IBS.We aimed to assess effects of tryptase and LPS on in vitro permeability using a 3-dimensional cell model after basolateral cell exposure. Furthermore, we assessed the extent to which these mediators in IBS plasma play a role in intestinal barrier function.Caco-2 cells were grown in extracellular matrix to develop into polarized spheroids and were exposed to tryptase (10 - 50 mU, LPS (1 - 50 ng/mL and two-fold diluted plasma samples of 7 patients with IBS-D, 7 with constipation-predominant IBS (IBS-C and 7 healthy controls (HC. Barrier function was assessed by the flux of FITC-dextran (FD4 using live cell imaging. Furthermore, plasma tryptase and LPS were determined.Tryptase (20 and 50 mU and LPS (6.25 - 50 ng/mL significantly increased Caco-2 permeability versus control (all P< 0.05. Plasma of IBS-D only showed significantly elevated median tryptase concentrations (7.1 [3.9 - 11.0] vs. 4.2 [2.2 - 7.0] vs. 4.2 [2.5 - 5.9] μg/mL; P<0.05 and LPS concentrations (3.65 [3.00 - 6.10] vs. 3.10 [2.60-3.80] vs. 2.65 [2.40 - 3.40] EU/ml; P< 0.05 vs. IBS-C and HC. Also, plasma of IBS-D increased Caco-2 permeability versus HC (0.14450 ± 0.00472 vs. 0.00021 ± 0.00003; P < 0.001, which was attenuated by selective inhibition of tryptase and LPS (P< 0.05.Basolateral exposure of spheroids to plasma of IBS-D patients resulted in a significantly increased FD4 permeation, which was partially abolished by selective inhibition of tryptase and LPS. These findings point to a role of systemic tryptase and LPS in the epithelial barrier alterations observed in patients with IBS-D.

Oxcarbazepine-loaded polymeric nanoparticles: development and permeability studies across in vitro models of the blood–brain barrier and human placental trophoblast

Science.gov (United States)

Lopalco, Antonio; Ali, Hazem; Denora, Nunzio; Rytting, Erik

2015-01-01

Encapsulation of antiepileptic drugs (AEDs) into nanoparticles may offer promise for treating pregnant women with epilepsy by improving brain delivery and limiting the transplacental permeability of AEDs to avoid fetal exposure and its consequent undesirable adverse effects. Oxcarbazepine-loaded nanoparticles were prepared by a modified solvent displacement method from biocompatible polymers (poly(lactic-co-glycolic acid) [PLGA] with or without surfactant and PEGylated PLGA [Resomer® RGPd5055]). The physical properties of the developed nanoparticles were determined with subsequent evaluation of their permeability across in vitro models of the blood–brain barrier (hCMEC/D3 cells) and human placental trophoblast cells (BeWo b30 cells). Oxcarbazepine-loaded nanoparticles with encapsulation efficiency above 69% were prepared with sizes ranging from 140–170 nm, polydispersity indices below 0.3, and zeta potential values below -34 mV. Differential scanning calorimetry and X-ray diffraction studies confirmed the amorphous state of the nanoencapsulated drug. The apparent permeability (Pe) values of the free and nanoencapsulated oxcarbazepine were comparable across both cell types, likely due to rapid drug release kinetics. Transport studies using fluorescently-labeled nanoparticles (loaded with coumarin-6) demonstrated increased permeability of surfactant-coated nanoparticles. Future developments in enzyme-prodrug therapy and targeted delivery are expected to provide improved options for pregnant patients with epilepsy. PMID:25792832

Downregulation of tight junction-associated MARVEL protein marvelD3 during epithelial-mesenchymal transition in human pancreatic cancer cells.

Science.gov (United States)

Kojima, Takashi; Takasawa, Akira; Kyuno, Daisuke; Ito, Tatsuya; Yamaguchi, Hiroshi; Hirata, Koichi; Tsujiwaki, Mitsuhiro; Murata, Masaki; Tanaka, Satoshi; Sawada, Norimasa

2011-10-01

The novel tight junction protein marvelD3 contains a conserved MARVEL (MAL and related proteins for vesicle trafficking and membrane link) domain like occludin and tricellulin. However, little is yet known about the detailed role and regulation of marvelD3 in normal epithelial cells and cancer cells, including pancreatic cancer. In the present study, we investigated marvelD3 expression in well and poorly differentiated human pancreatic cancer cell lines and normal pancreatic duct epithelial cells in which the hTERT gene was introduced into human pancreatic duct epithelial cells in primary culture, and the changes of marvelD3 during Snail-induced epithelial-mesenchymal transition (EMT) under hypoxia, TGF-β treatment and knockdown of FOXA2 in well differentiated pancreatic cancer HPAC cells. MarvelD3 was transcriptionally downregulated in poorly differentiated pancreatic cancer cells and during Snail-induced EMT of pancreatic cancer cells in which Snail was highly expressed and the fence function downregulated, whereas it was maintained in well differentiated human pancreatic cancer cells and normal pancreatic duct epithelial cells. Depletion of marvelD3 by siRNAs in HPAC cells resulted in downregulation of barrier functions indicated as a decrease in transepithelial electric resistance and an increase of permeability to fluorescent dextran tracers, whereas it did not affect fence function of tight junctions. In conclusion, marvelD3 is transcriptionally downregulated in Snail-induced EMT during the progression for the pancreatic cancer. Copyright © 2011 Elsevier Inc. All rights reserved.

Evaluation of performance of barrier materials in geological disposal of radioactive waste

International Nuclear Information System (INIS)

Sasakura, Takeshi; Kobayashi, Ichizo

2004-01-01

It is important to evaluate the hydraulic and mechanical performance of barrier materials for geological disposal of radioactive waste. Many experiments on the hydraulic and mechanical performance of barrier materials have been implemented. However, both the ordinary water head-controlled permeability test for evaluating hydraulic performance and the oedometer test for obtaining the mechanical properties are usually needed. In this study, the flow pump permeability test was applied to various barrier materials with the purpose of quickly evaluating their hydraulic performance. The flow pump permeability test was shown to be applicable to every barrier material employed in this study, of which the coefficient of permeability ranged from 10-7 to 10-14 m/sec. The time needed to obtain the coefficient of permeability was about 1/8 that of ordinary head-controlled permeability tests. The resulting coefficient of permeability was more accurate than that from the standard water head-controlled permeability test. Moreover, the bentonite-engineered barrier materials were subjected to a constant strain rate consolidation test, which is a method to quickly evaluate the mechanical performance. The results of the consolidation tests were consistent with the results of the oedometer tests and the necessary time for the test was reduced to only four days even in case of Na-ben-tonite, for which a couple of months was necessary with the standard oedometer test. (author)

Barriers and post-closure monitoring (AL121125)

International Nuclear Information System (INIS)

Bostick, K.V.; Janecky, D.

1995-01-01

This project focuses on the rapid implementation of near-surface barriers, biotreatment, and post-closure monitoring technology. It uses water-permeable and biologic barriers that chemically capture and/or degrade contaminants without significantly altering the natural water flow regime. Barrier approaches are being tested for two different applications. The first is the use of barriers for confinement of chemical contaminants for in-trench treatments with leach systems or an in-place bioreactor. The second is an enhancement of the current practice of emplacing grout or clay slurry walls into direct horizontal surface and subsurface water flows around a contaminated area by integrating permeable reactive barriers and petroleum reservoir gel/foam/polymer technology

Role of mitochondrial permeability transition in human renal tubular epithelial cell death induced by aristolochic acid

International Nuclear Information System (INIS)

Qi Xinming; Cai Yan; Gong Likun; Liu Linlin; Chen Fangping; Xiao Ying; Wu Xiongfei; Li Yan; Xue Xiang; Ren Jin

2007-01-01

Aristolochic acid (AA), a natural nephrotoxin and carcinogen, can induce a progressive tubulointerstitial nephropathy. However, the mechanism by which AA causes renal injury remains largely unknown. Here we reported that the mitochondrial permeability transition (MPT) plays an important role in the renal injury induced by aristolochic acid I (AAI). We found that in the presence of Ca 2+ , AAI caused mitochondrial swelling, leakage of Ca 2+ , membrane depolarization, and release of cytochrome c in isolated kidney mitochondria. These alterations were suppressed by cyclosporin A (CsA), an agent known to inhibit MPT. Culture of HK-2 cell, a human renal tubular epithelial cell line for 24 h with AAI caused a decrease in cellular ATP, mitochondrial membrane depolarization, cytochrome c release, and increase of caspase 3 activity. These toxic effects of AAI were attenuated by CsA and bongkrekic acid (BA), another specific MPT inhibitor. Furthermore, AAI greatly inhibited the activity of mitochondrial adenine nucleotide translocator (ANT) in isolated mitochondria. We suggested that ANT may mediate, at least in part, the AAI-induced MPT. Taken together, these results suggested that MPT plays a critical role in the pathogenesis of HK-2 cell injury induced by AAI and implied that MPT might contribute to human nephrotoxicity of aristolochic acid

Intestinal barrier integrity and inflammatory bowel disease

DEFF Research Database (Denmark)

Holmberg, Fredrik Eric Olof; Pedersen, Jannie; Jørgensen, Peter

2018-01-01

Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression of antim......Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression...... of antimicrobial peptides. Inflammatory bowel disease is associated with life-long morbidity for affected patients, and both the incidence and prevalence is increasing globally, resulting in substantial economic strain for society. Mucosal healing and re-establishment of barrier integrity is associated......, novel treatment strategies to accomplish mucosal healing and to re-establish normal barrier integrity in inflammatory bowel disease are warranted, and luminal stem cell-based approaches might have an intriguing potential. Transplantation of in vitro expanded intestinal epithelial stem cells derived...

T-Lymphocytes Traffic into the Brain across the Blood-CSF Barrier: Evidence Using a Reconstituted Choroid Plexus Epithelium.

Science.gov (United States)

Strazielle, Nathalie; Creidy, Rita; Malcus, Christophe; Boucraut, José; Ghersi-Egea, Jean-François

2016-01-01

An emerging concept of normal brain immune surveillance proposes that recently and moderately activated central memory T lymphocytes enter the central nervous system (CNS) directly into the cerebrospinal fluid (CSF) via the choroid plexus. Within the CSF space, T cells inspect the CNS environment for cognate antigens. This gate of entry into the CNS could also prevail at the initial stage of neuroinflammatory processes. To actually demonstrate T cell migration across the choroidal epithelium forming the blood-CSF barrier, an in vitro model of the rat blood-CSF barrier was established in an "inverse" configuration that enables cell transmigration studies in the basolateral to apical, i.e. blood/stroma to CSF direction. Structural barrier features were evaluated by immunocytochemical analysis of tight junction proteins, functional barrier properties were assessed by measuring the monolayer permeability to sucrose and the active efflux transport of organic anions. The migratory behaviour of activated T cells across the choroidal epithelium was analysed in the presence and absence of chemokines. The migration pathway was examined by confocal microscopy. The inverse rat BCSFB model reproduces the continuous distribution of tight junction proteins at cell margins, the restricted paracellular permeability, and polarized active transport mechanisms, which all contribute to the barrier phenotype in vivo. Using this model, we present experimental evidence of T cell migration across the choroidal epithelium. Cell migration appears to occur via a paracellular route without disrupting the restrictive barrier properties of the epithelial interface. Apical chemokine addition strongly stimulates T cell migration across the choroidal epithelium. The present data provide evidence for the controlled migration of T cells across the blood-CSF barrier into brain. They further indicate that this recruitment route is sensitive to CSF-borne chemokines, extending the relevance of this

Scintigraphic assessment of vascularity and blood-tissue barrier of human brain tumours

International Nuclear Information System (INIS)

Front, D.

1978-01-01

Assessment of vascularity and blood-tissue barrier was performed by sequential scintigraphy in 43 patients with brain tumours. The blood-tumour barrier was evaluated by use of sup(99m)Tc-pertechnetate, and vascularity using sup(99m)Tc-labelled red blood cells. Three groups of tumours were found: tumours with low vascularity and permeable barrier, tumours with high vascularity and permeable barrier, and tumours with low vascularity and relatively impermeable barrier. The first group indicates that when vessels are permeable, there may be a rapid penetration of large amounts of pertechnetate into the tumour even when vascularity is not increased. In the other two groups penetration of pertechnetate into the tumour is affected by vascularity, as it determines the total area where passage of the radiopharmaceutical takes place. It is suggested that the permeability of the blood-tumour barrier and the amount of vascularity may have an effect on the success of chemotherapy in brain tumours. (author)

The Effect of Green Inhibitor on strength and water permeability of ...

African Journals Online (AJOL)

... present in the concrete evident from inductively coupled plasma-mass spectrometry (ICPMS) result. KOH is adequate for passivation and reduction of permeability, which serve as a chemical water barriers or hydrophobic agents. Keywords: Concrete; Calcium-Silicate-Hydrate (C-S-H); Compressive strength; Permeability; ...

REMOVAL OF ADDED NITRATE IN THE SINGLE, BINARY, AND TERNARY SYSTEMS OF COTTON BURR COMPOST, ZEROVALENT IRON, AND SEDIMENT: IMPLICATIONS FOR GROUNDWATER NITRATE REMEDIATION USING PERMEABLE REACTIVE BARRIERS

Science.gov (United States)

Recent research has shown that carbonaceous solid materials and zerovalent iron (Fe0) may potentially be used as media in permeable reactive barriers (PRBs) to degrade groundwater nitrate via heterotrophic denitrification in the solid carbon system, and via abiotic reduction and ...

Small-bowel permeability in collagenous colitis

DEFF Research Database (Denmark)

Wildt, Signe; Madsen, Jan L; Rumessen, Jüri J

2006-01-01

Collagenous colitis (CC) is a chronic inflammatory bowel disease that affects the colon. However, some patients with CC present with accompanying pathologic small-bowel manifestations such as coeliac disease, defects in bile acid absorption and histopathologic changes in small-intestinal biopsies......, indicating that CC is a pan-intestinal disease. In small-intestinal disease, the intestinal barrier function may be impaired, and the permeability of the small intestine altered. The purpose of this research was to study small-bowel function in patients with CC as expressed by intestinal permeability....

Stepwise DNA Methylation Changes Are Linked to Escape from Defined Proliferation Barriers and Mammary Epithelial Cell Immortalization

Energy Technology Data Exchange (ETDEWEB)

Novak, Petr; Jensen, Taylor J.; Garbe, James C.; Stampfer, Martha R.; Futscher, Bernard W.

2009-04-20

The timing and progression of DNA methylation changes during carcinogenesis are not completely understood. To develop a timeline of aberrant DNA methylation events during malignant transformation, we analyzed genome-wide DNA methylation patterns in an isogenic human mammary epithelial cell (HMEC) culture model of transformation. To acquire immortality and malignancy, the cultured finite lifespan HMEC must overcome two distinct proliferation barriers. The first barrier, stasis, is mediated by the retinoblastoma protein and can be overcome by loss of p16(INK4A) expression. HMEC that escape stasis and continue to proliferate become genomically unstable before encountering a second more stringent proliferation barrier, telomere dysfunction due to telomere attrition. Rare cells that acquire telomerase expression may escape this barrier, become immortal, and develop further malignant properties. Our analysis of HMEC transitioning from finite lifespan to malignantly transformed showed that aberrant DNA methylation changes occur in a stepwise fashion early in the transformation process. The first aberrant DNA methylation step coincides with overcoming stasis, and results in few to hundreds of changes, depending on how stasis was overcome. A second step coincides with immortalization and results in hundreds of additional DNA methylation changes regardless of the immortalization pathway. A majority of these DNA methylation changes are also found in malignant breast cancer cells. These results show that large-scale epigenetic remodeling occurs in the earliest steps of mammary carcinogenesis, temporally links DNA methylation changes and overcoming cellular proliferation barriers, and provides a bank of potential epigenetic biomarkers that mayprove useful in breast cancer risk assessment.

GAS PERMEABILITY OF GEOSYNTHETIC CLAY LINERS

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Helena Vučenović

2017-01-01

Full Text Available Geosynthetic clay liners (GCL are manufactured hydraulic barriers consisting of mineral and geosynthetic components. They belong to a group of geosynthetic products whose primary purpose is to seal and they have been used in many geotechnical and hydrotechnical applications, landfi lls and liquid waste lagoons for quite a while. They are used in landfill final cover systems to prevent the infi ltration of precipitation into the landfi ll body and the penetration of gases and liquids from the landfill into the atmosphere and environment. Laboratory and fi eld research and observations on regulated landfi lls have proven the eff ectiveness of GCL as a barrier for the infi ltration of precipitation into the landfi ll body as well as the drainage of fl uid beneath the landfill. Due to the presence of high concentrations of gases in the landfill body, there is a growing interest in determining the efficiency of GCL as a gas barrier. It was not until the last twenty years that the importance of this topic was recognized. In this article, current GCL gas permeability studies, the testing methods and test results of gas permeability in laboratory conditions are described.

Regulation of defensive function on gingival epithelial cells can prevent periodontal disease.

Science.gov (United States)

Fujita, Tsuyoshi; Yoshimoto, Tetsuya; Kajiya, Mikihito; Ouhara, Kazuhisa; Matsuda, Shinji; Takemura, Tasuku; Akutagawa, Keiichi; Takeda, Katsuhiro; Mizuno, Noriyoshi; Kurihara, Hidemi

2018-05-01

Periodontal disease is a bacterial biofilm-associated inflammatory disease that has been implicated in many systemic diseases. A new preventive method for periodontal disease needs to be developed in order to promote the health of the elderly in a super-aged society. The gingival epithelium plays an important role as a mechanical barrier against bacterial invasion and a part of the innate immune response to infectious inflammation in periodontal tissue. The disorganization of cell-cell interactions and subsequent inflammation contribute to the initiation of periodontal disease. These make us consider that regulation of host defensive functions, epithelial barrier and neutrophil activity, may become novel preventive methods for periodontal inflammation. Based on this concept, we have found that several agents regulate the barrier function of gingival epithelial cells and suppress the accumulation of neutrophils in the gingival epithelium. We herein introduce the actions of irsogladine maleate, azithromycin, amphotericin B, and Houttuynia cordata (dokudami in Japanese), which is commonly used in traditional medicine, on the epithelial barrier and neutrophil migration in gingival epithelial cells in vivo and in vitro , in order to provide support for the clinical application of these agents to the prevention of periodontal inflammation.

Unexpected effects of peripherally administered kynurenic acid on cortical spreading depression and related blood–brain barrier permeability

Directory of Open Access Journals (Sweden)

Oláh G

2013-09-01

Full Text Available Gáspár Oláh,1 Judit Herédi,1 Ákos Menyhárt,1 Zsolt Czinege,2 Dávid Nagy,1 János Fuzik,1 Kitti Kocsis,1 Levente Knapp,1 Erika Krucsó,1 Levente Gellért,1 Zsolt Kis,1 Tamás Farkas,1 Ferenc Fülöp,3 Árpád Párdutz,4 János Tajti,4 László Vécsei,4 József Toldi1 1Department of Physiology, Anatomy and Neuroscience, 2Department of Software Engineering, 3Institute of Pharmaceutical Chemistry and MTA-SZTE Research Group for Stereochemistry, 4Department of Neurology and MTA-SZTE Neuroscience Research Group, University of Szeged, Szeged, Hungary Abstract: Cortical spreading depression (CSD involves a slowly-propagating depolarization wave in the cortex, which can appear in numerous pathophysiological conditions, such as migraine with aura, stroke, and traumatic brain injury. Neurons and glial cells are also depolarized transiently during the phenomena. CSD is followed by a massive increase in glutamate release and by changes in the brain microcirculation. The aim of this study was to investigate the effects of two N-methyl-D-aspartate receptor antagonists, endogenous kynurenic acid (KYNA and dizocilpine, on CSD and the related blood–brain barrier (BBB permeability in rats. In intact animals, KYNA hardly crosses the BBB but has some positive features as compared with its precursor L-Kynurenine, which is frequently used in animal studies (KYNA cannot be metabolized to excitotoxic agents such as 3-hydroxy-L-kynurenine and quinolinic acid. We therefore investigated the possible effects of peripherally administered KYNA. Repetitive CSD waves were elicited by the application of 1 M KCl solution to the cortex. Direct current-electrocorticograms were measured for 1 hour. Four parameters of the waves were compared. Evans blue dye and fluorescent microscopy were used to study the possible changes in the permeability of the BBB. The results demonstrated that N-methyl-D-aspartate receptor antagonists can reduce the number of CSD waves and decrease

Using dissolved gas analysis to investigate the performance of an organic carbon permeable reactive barrier for the treatment of mine drainage

Science.gov (United States)

Williams, R.L.; Mayer, K.U.; Amos, R.T.; Blowes, D.W.; Ptacek, C.J.; Bain, J.G.

2007-01-01

The strongly reducing nature of permeable reactive barrier (PRB) treatment materials can lead to gas production, potentially resulting in the formation of gas bubbles and ebullition. Degassing in organic C based PRB systems due to the production of gases (primarily CO2 and CH4) is investigated using the depletion of naturally occurring non-reactive gases Ar and N2, to identify, confirm, and quantify chemical and physical processes. Sampling and analysis of dissolved gases were performed at the Nickel Rim Mine Organic Carbon PRB, which was designed for the treatment of groundwater contaminated by low quality mine drainage characterized by slightly acidic pH, and elevated Fe(II) and SO4 concentrations. A simple 4-gas degassing model was used to analyze the dissolved gas data, and the results indicate that SO4 reduction is by far the dominant process of organic C consumption within the barrier. The data provided additional information to delineate rates of microbially mediated SO4 reduction and confirm the presence of slow and fast flow zones within the barrier. Degassing was incorporated into multicomponent reactive transport simulations for the barrier and the simulations were successful in reproducing observed dissolved gas trends.

The Blood-Brain Barrier Permeability of Six Indole Alkaloids from Uncariae Ramulus Cum Uncis in the MDCK-pHaMDR Cell Monolayer Model

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Yi-Nan Zhang

2017-11-01

Full Text Available Uncariae Ramulus Cum Uncis (URCU is a widely used traditional Chinese medicine, and is reported to have various central nervous system effects. Alkaloids have been demonstrated to be the predominant pharmacological active components of URCU. In order to evaluate the blood-brain barrier (BBB permeability and transport mechanism of six typical indole alkaloids from URCU, the MDCK-pHaMDR cell monolayer model was used as an in vitro surrogate model for BBB. The samples were analyzed by high-performance liquid chromatography, and the apparent permeability coefficients (Papp were calculated. Among the six alkaloids, isorhynchophylline (2, isocorynoxeine (4, hirsutine (5 and hirsuteine (6 showed high permeability, with Papp values at 10−5 cm/s level in bidirectional transport. For rhynchophylline (1 and corynoxeine (3, they showed moderate permeability, with Papp values from the apical (AP side to the basolateral (BL side at 10−6 cm/s level and efflux ratio (Papp BL→AP/Papp AP→BL above 2. The time- and concentration-dependency experiments indicated that the main mechanism for 2, 4, 5 and 6 through BBB was passive diffusion. The efflux mechanism involved in the transports of compounds 1 and 3 could be reduced significantly by verapamil, and molecular docking screening also showed that 1 and 3 had strong bindings to P-glycoprotein. This study provides useful information for predicting the BBB permeability for 1–6, as well as better understanding of their central nervous system pharmacological activities.

Structure and barrier properties of human embryonic stem cell-derived retinal pigment epithelial cells are affected by extracellular matrix protein coating.

Science.gov (United States)

Sorkio, Anni; Hongisto, Heidi; Kaarniranta, Kai; Uusitalo, Hannu; Juuti-Uusitalo, Kati; Skottman, Heli

2014-02-01

Extracellular matrix (ECM) interactions play a vital role in cell morphology, migration, proliferation, and differentiation of cells. We investigated the role of ECM proteins on the structure and function of human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells during their differentiation and maturation from hESCs into RPE cells in adherent differentiation cultures on several human ECM proteins found in native human Bruch's membrane, namely, collagen I, collagen IV, laminin, fibronectin, and vitronectin, as well as on commercial substrates of xeno-free CELLstart™ and Matrigel™. Cell pigmentation, expression of RPE-specific proteins, fine structure, as well as the production of basal lamina by hESC-RPE on different protein coatings were evaluated after 140 days of differentiation. The integrity of hESC-RPE epithelium and barrier properties on different coatings were investigated by measuring transepithelial resistance. All coatings supported the differentiation of hESC-RPE cells as demonstrated by early onset of cell pigmentation and further maturation to RPE monolayers after enrichment. Mature RPE phenotype was verified by RPE-specific gene and protein expression, correct epithelial polarization, and phagocytic activity. Significant differences were found in the degree of RPE cell pigmentation and tightness of epithelial barrier between different coatings. Further, the thickness of self-assembled basal lamina and secretion of the key ECM proteins found in the basement membrane of the native RPE varied between hESC-RPE cultured on compared protein coatings. In conclusion, this study shows that the cell culture substrate has a major effect on the structure and basal lamina production during the differentiation and maturation of hESC-RPE potentially influencing the success of cell integrations and survival after cell transplantation.

Diabetic and sympathetic influences on the water permeability barrier function of human skin as measured using transepidermal water loss: A case-control study.

Science.gov (United States)

Han, Seung Hoon; Park, Ji Woong

2017-11-01

The presence of long-standing hyperglycemic conditions has been suggested to lead to many skin problems associated with an impaired skin barrier function. However, the relationship between impaired skin barrier status and altered peripheral nervous system function has not yet been determined. The purpose of this study was to investigate the water evaporation rate as a measure of the permeability barrier function of diabetic skin and its relationship to diabetic sensorimotor polyneuropathy (DSPN) and peripheral autonomic neuropathy (PAN) using well-controlled confounding variables.This case-control study included 42 participants with chronic diabetes and 43 matched healthy controls. The diabetic group underwent a nerve conduction study and sympathetic skin response (SSR) test to confirm the presence of DSPN and PAN, respectively. Different skin regions were analyzed using the noninvasive Tewameter instrument (Courage + Khazaka Electronic GmbH, Cologne, Germany). The impacts of PAN, DSPN, age, and diabetes duration on the values of transepidermal water loss (TEWL) were each analyzed and compared between the groups.Regardless of the presence of DSPN or PAN, the TEWL values as measured on the distal extremities were significantly lower in the diabetic group than in the control group. In the diabetic group, participants with abnormal SSR test results showed decreased TEWL values in the finger, sole, and first toe, as compared with participants with normal SSR test results. In the control group, age showed a negative correlation with the TEWL values with respect to some measured regions. However, in the diabetic group, there was no significant correlation between either patient age or diabetes duration and TEWL values.The presence of a long-term hyperglycemic state can reduce the permeability barrier function of the skin, a phenomenon that might be related to the presence of an impaired peripheral sympathetic nervous system, rather than peripheral sensorimotor

Modeling localized delivery of Doxorubicin to the brain following focused ultrasound enhanced blood-brain barrier permeability

International Nuclear Information System (INIS)

Nhan, Tam; Burgess, Alison; Hynynen, Kullervo; Lilge, Lothar

2014-01-01

Doxorubicin (Dox) is a well-established chemotherapeutic agent, however it has limited efficacy in treating brain malignancies due to the presence of the blood-brain barrier (BBB). Recent preclinical studies have demonstrated that focused ultrasound induced BBB disruption (BBBD) enables efficient delivery of Dox to the brain. For future treatment planning of BBBD-based drug delivery, it is crucial to establish a mathematical framework to predict the effect of transient BBB permeability enhancement on the spatiotemporal distribution of Dox at the targeted area. The constructed model considers Dox concentrations within three compartments (plasma, extracellular, intracellular) that are governed by various transport processes (e.g. diffusion in interstitial space, exchange across vessel wall, clearance by cerebral spinal fluid, uptake by brain cells). By examining several clinical treatment aspects (e.g. sonication scheme, permeability enhancement, injection mode), our simulation results support the experimental findings of optimal interval delay between two consecutive sonications and therapeutically-sufficient intracellular concentration with respect to transfer constant K trans range of 0.01–0.03 min −1 . Finally, the model suggests that infusion over a short duration (20–60 min) should be employed along with single-sonication or multiple-sonication at 10 min interval to ensure maximum delivery to the intracellular compartment while attaining minimal cardiotoxicity via suppressing peak plasma concentration. (paper)

Toll-Like Receptor 2 Activation by beta 2 -> 1-Fructans Protects Barrier Function of T84 Human Intestinal Epithelial Cells in a Chain Length-Dependent Manner

NARCIS (Netherlands)

Vogt, Leonie M.; Meyer, Diederick; Pullens, Gerdie; Faas, Marijke M.; Venema, Koen; Ramasamy, Uttara; Schols, Henk A.; de Vos, Paul

Dietary fiber intake is associated with lower incidence and mortality from disease, but the underlying mechanisms of these protective effects are unclear. We hypothesized that beta 2 -> 1-fructan dietary fibers confer protection on intestinal epithelial cell barrier function via Toll-like receptor 2

Zinc Supplementation, via GPR39, Upregulates PKCζ to Protect Intestinal Barrier Integrity in Caco-2 Cells Challenged by Salmonella enterica Serovar Typhimurium.

Science.gov (United States)

Shao, Yu-Xin; Lei, Zhao; Wolf, Patricia G; Gao, Yan; Guo, Yu-Ming; Zhang, Bing-Kun

2017-07-01

Background: Zinc has been shown to improve intestinal barrier function against Salmonella enterica serovar Typhimurium ( S. typhimurium ) infection, but the mechanisms involved in this process remain undefined. Objective: We aimed to explore the roles of G protein-coupled receptor (GPR)39 and protein kinase Cζ (PKCζ) in the regulation by zinc of intestinal barrier function. Methods: A Transwell Caco-2 monolayer was pretreated with 0, 50, or 100 μM Zn and then incubated with S. typhimurium for 0-6 h. Afterward, cells silenced by the small interfering RNA for GPR39 or PKCζ were pretreated with 100 μM Zn and incubated with S. typhimurium for 3 h. Finally, transepithelial electrical resistance (TEER), permeability, tight junction (TJ) proteins, and signaling molecules GPR39 and PKCζ were measured. Results: Compared with controls, S. typhimurium decreased TEER by 62.3-96.2% at 4-6 h ( P 0.1). Silencing GPR39 decreased ( P zinc-activated PKCζ and blocked ( P zinc on epithelial integrity. Furthermore, silencing PKCζ counteracted the protective effect of zinc on epithelial integrity but did not inhibit GPR39 ( P = 0.138). Conclusion: We demonstrated that zinc upregulates PKCζ by activating GPR39 to enhance the abundance of ZO-1, thereby improving epithelial integrity in S. typhimurium- infected Caco-2 cells. © 2017 American Society for Nutrition.

Contamination movement around a permeable reactive barrier at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina, 2009

Science.gov (United States)

Vroblesky, Don A.; Petkewich, Matthew D.; Conlon, Kevin J.

2010-01-01

The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated volatile organic compound groundwater contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina, beginning in 2000. In early 2004, groundwater contaminants began moving around the southern end of a permeable reactive barrier (PRB) installed by a consultant in December 2002. The PRB is a 130-foot-long and 3-foot-wide barrier consisting of varying amounts of zero-valent iron with or without sand mixture. Contamination moving around the PRB probably has been transported at least 75 feet downgradient from the PRB at a rate of about 15 to 29 feet per year.

Evaluation of permeability of compacted bentonite ground considering heterogeneity by geostatistics

International Nuclear Information System (INIS)

Tanaka, Yukihisa; Nakamura, Kunihiko; Kudo, Kohji; Hironaga, Michihiko; Nakagami, Motonori; Niwase, Kazuhito; Komatsu, Shin-ichi

2007-01-01

The permeability of the bentonite ground as an engineered barrier is possibly designed to the value which is lower than that determined in terms of required performance because of heterogeneous distribution of permeability in the ground, which might be considerable when the ground is created by the compaction method. The effect of heterogeneity in the ground on the permeability of the bentonite ground should be evaluated by overall permeability of the ground, whereas in practice, the effect is evaluated by the distribution of permeability in the ground. Thus, in this study, overall permeability of the bentonite ground is evaluated from the permeability of the bentonite ground is evaluated from the permeability distribution determined using the geostatistical method with the dry density data as well as permeability data of the undisturbed sample recovered from the bentonite ground. Consequently, it was proved through this study that possibility of overestimation of permeability of the bentonite ground can be reduced if the overall permeability is used. (author)

Cytotoxicity of Different Excipients on RPMI 2650 Human Nasal Epithelial Cells

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Tamás Horváth

2016-05-01

Full Text Available The nasal route receives a great deal of attention as a non-invasive method for the systemic administration of drugs. For nasal delivery, specific formulations containing excipients are used. Because of the sensitive respiratory mucosa, not only the active ingredients, but also additives need to be tested in appropriate models for toxicity. The aim of the study was to measure the cytotoxicity of six pharmaceutical excipients, which could help to reach larger residence time, better permeability, and increased solubility dissolution rate. The following excipients were investigated on RPMI 2650 human nasal septum tumor epithelial cells: β-d-mannitol, sodium hyaluronate, α and β-cyclodextrin, polyvinyl alcohol and methylcellulose. 3-(4,5-dimethyltiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT dye conversion assay and real-time impedance analysis were used to investigate cytotoxicity. No excipient showed toxicity at 0.3% (w/v concentration or below while 1% concentration a significantly reduced metabolic activity was measured by MTT assay for methylcellulose and cyclodextrins. Using impedance measurements, only β-cyclodextrin (1% was toxic to cells. Mannitol at 1% concentration had a barrier opening effect on epithelial cells, but caused no cellular damage. Based on the results, all additives at 0.3%, sodium hyaluronate and polyvinyl alcohol at 1% concentrations can be safely used for nasal formulations.

Transcranial direct current stimulation transiently increases the blood-brain barrier solute permeability in vivo

Science.gov (United States)

Shin, Da Wi; Khadka, Niranjan; Fan, Jie; Bikson, Marom; Fu, Bingmei M.

2016-03-01

Transcranial Direct Current Stimulation (tDCS) is a non-invasive electrical stimulation technique investigated for a broad range of medical and performance indications. Whereas prior studies have focused exclusively on direct neuron polarization, our hypothesis is that tDCS directly modulates endothelial cells leading to transient changes in blood-brain-barrier (BBB) permeability (P) that are highly meaningful for neuronal activity. For this, we developed state-of-the-art imaging and animal models to quantify P to various sized solutes after tDCS treatment. tDCS was administered using a constant current stimulator to deliver a 1mA current to the right frontal cortex of rat (approximately 2 mm posterior to bregma and 2 mm right to sagittal suture) to obtain similar physiological outcome as that in the human tDCS application studies. Sodium fluorescein (MW=376), or FITC-dextrans (20K and 70K), in 1% BSA mammalian Ringer was injected into the rat (SD, 250-300g) cerebral circulation via the ipsilateral carotid artery by a syringe pump at a constant rate of ~3 ml/min. To determine P, multiphoton microscopy with 800-850 nm wavelength laser was applied to take the images from the region of interest (ROI) with proper microvessels, which are 100-200 micron below the pia mater. It shows that the relative increase in P is about 8-fold for small solute, sodium fluorescein, ~35-fold for both intermediate sized (Dex-20k) and large (Dex-70k) solutes, 10 min after 20 min tDCS pretreatment. All of the increased permeability returns to the control after 20 min post treatment. The results confirmed our hypothesis.

Erythropoietin protects the retinal pigment epithelial barrier against ...

African Journals Online (AJOL)

O2-induced hyperpermeability. H Zhang, Y Gong, X Wu, Y Shi, L Yin, Y Qiu. Abstract. Erythropoietin (EPO) is not limited to hematopoiesis; it may act as a protective cytokine. In this study, the retinal pigment epithelial (RPE) cell viability, cell ...

Permeable reactive barrier - innovative technology for ground-water remediation

International Nuclear Information System (INIS)

Vidic, D.R.

2002-01-01

Significant advances in the application of permeable reactive barriers (PRBs) for ground-water remediation have been witnessed in the last 5 years. From only a few full-scale systems and pilot-scale demonstrations, there are currently at least 38 full-scale PRBs using zero-valent iron (ZVI) as a reactive material. Of those, 26 are continuous reactive walls, 9 are funnel-and- gate systems and 3 are in situ reactive vessels. Most of the PRB systems have used granular iron media and have been applied to address the control of contamination caused by chlorinated volatile organic compounds or heavy metals. Many regulatory agencies have expressed interest in PRB systems and are becoming more comfortable in issuing permits. The main advantage of PRB systems is that the installation costs are comparable with those of other ground-water remediation technologies, while the O and M costs are significantly lower and are mostly due to monitoring requirements, which are required for all remediation approaches. In addition, the land use can resume after the installation of the PRB systems, since there are few visible signs of the installation above grounds except for the monitoring wells. It is difficult to make any definite conclusions about the long-term performance of PRB systems because there is no more than 5 years of the record of performance that can be used for such analysis. The two main challenges still facing this technology are: (1) evaluating the longevity (geochemistry) of a PRB; and (2) ensuring/verifying hydraulic performance. A number of public/private partnerships have been established in recent years that are working together to resolve some of these problems. This organized approach by combining the efforts of several government agencies and private companies will likely result in better understanding and, hopefully, better acceptance of this technology in the future. (author)

Comparative study of four immortalized human brain capillary endothelial cell lines, hCMEC/D3, hBMEC, TY10, and BB19, and optimization of culture conditions, for an in vitro blood-brain barrier model for drug permeability studies.

Science.gov (United States)

Eigenmann, Daniela E; Xue, Gongda; Kim, Kwang S; Moses, Ashlee V; Hamburger, Matthias; Oufir, Mouhssin

2013-11-22

Reliable human in vitro blood-brain barrier (BBB) models suitable for high-throughput screening are urgently needed in early drug discovery and development for assessing the ability of promising bioactive compounds to overcome the BBB. To establish an improved human in vitro BBB model, we compared four currently available and well characterized immortalized human brain capillary endothelial cell lines, hCMEC/D3, hBMEC, TY10, and BB19, with respect to barrier tightness and paracellular permeability. Co-culture systems using immortalized human astrocytes (SVG-A cell line) and immortalized human pericytes (HBPCT cell line) were designed with the aim of positively influencing barrier tightness. Tight junction (TJ) formation was assessed by transendothelial electrical resistance (TEER) measurements using a conventional epithelial voltohmmeter (EVOM) and an automated CellZscope system which records TEER and cell layer capacitance (CCL) in real-time.Paracellular permeability was assessed using two fluorescent marker compounds with low BBB penetration (sodium fluorescein (Na-F) and lucifer yellow (LY)). Conditions were optimized for each endothelial cell line by screening a series of 24-well tissue culture inserts from different providers. For hBMEC cells, further optimization was carried out by varying coating material, coating procedure, cell seeding density, and growth media composition. Biochemical characterization of cell type-specific transmembrane adherens junction protein VE-cadherin and of TJ proteins ZO-1 and claudin-5 were carried out for each endothelial cell line. In addition, immunostaining for ZO-1 in hBMEC cell line was performed. The four cell lines all expressed the endothelial cell type-specific adherens junction protein VE-cadherin. The TJ protein ZO-1 was expressed in hCMEC/D3 and in hBMEC cells. ZO-1 expression could be confirmed in hBMEC cells by immunocytochemical staining. Claudin-5 expression was detected in hCMEC/D3, TY10, and at a very low level

Membrane lipidome of an epithelial cell line

DEFF Research Database (Denmark)

Sampaio, Julio L; Gerl, Mathias J; Klose, Christian

2011-01-01

Tissue differentiation is an important process that involves major cellular membrane remodeling. We used Madin-Darby canine kidney cells as a model for epithelium formation and investigated the remodeling of the total cell membrane lipidome during the transition from a nonpolarized morphology...... to an epithelial morphology and vice versa. To achieve this, we developed a shotgun-based lipidomics workflow that enabled the absolute quantification of mammalian membrane lipidomes with minimal sample processing from low sample amounts. Epithelial morphogenesis was accompanied by a major shift from sphingomyelin...... to generate an apical membrane domain that serves as a protective barrier for the epithelial sheet....

Nlrp3 prevents early renal interstitial edema and vascular permeability in unilateral ureteral obstruction.

Directory of Open Access Journals (Sweden)

Wilco P Pulskens

Full Text Available Progressive renal disease is characterized by tubulo-interstitial injury with ongoing inflammation and fibrosis. The Nlrp3 inflammasome contributes to these pathophysiological processes through its canonical effects in cytokine maturation. Nlrp3 may additionally exert inflammasome-independent effects following tissue injury. Hence, in this study we investigated potential non-canonical effects of Nlrp3 following progressive renal injury by subjecting WT and Nlrp3-deficient (-/- mice to unilateral ureter obstruction (UUO. Our results revealed a progressive increase of renal Nlrp3 mRNA in WT mice following UUO. The absence of Nlrp3 resulted in enhanced tubular injury and dilatation and an elevated expression of injury biomarker NGAL after UUO. Moreover, interstitial edema was significantly elevated in Nlrp3-/- mice. This could be explained by increased intratubular pressure and an enhanced tubular and vascular permeability. In accordance, renal vascular leakage was elevated in Nlrp3-/- mice that associated with reduced mRNA expression of intercellular junction components. The decreased epithelial barrier function in Nlrp3-/- mice was not associated with increased apoptosis and/or proliferation of renal epithelial cells. Nlrp3 deficiency did not affect renal fibrosis or inflammation. Together, our data reveal a novel non-canonical effect of Nlrp3 in preserving renal integrity and protection against early tubular injury and interstitial edema following progressive renal injury.

Modelling the endothelial blood-CNS barriers: a method for the production of robust in vitro models of the rat blood-brain barrier and blood-spinal cord barrier.

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Watson, P Marc D; Paterson, Judy C; Thom, George; Ginman, Ulrika; Lundquist, Stefan; Webster, Carl I

2013-06-18

Modelling the blood-CNS barriers of the brain and spinal cord in vitro continues to provide a considerable challenge for research studying the passage of large and small molecules in and out of the central nervous system, both within the context of basic biology and for pharmaceutical drug discovery. Although there has been considerable success over the previous two decades in establishing useful in vitro primary endothelial cell cultures from the blood-CNS barriers, no model fully mimics the high electrical resistance, low paracellular permeability and selective influx/efflux characteristics of the in vivo situation. Furthermore, such primary-derived cultures are typically labour-intensive and generate low yields of cells, limiting scope for experimental work. We thus aimed to establish protocols for the high yield isolation and culture of endothelial cells from both rat brain and spinal cord. Our aim was to optimise in vitro conditions for inducing phenotypic characteristics in these cells that were reminiscent of the in vivo situation, such that they developed into tight endothelial barriers suitable for performing investigative biology and permeability studies. Brain and spinal cord tissue was taken from the same rats and used to specifically isolate endothelial cells to reconstitute as in vitro blood-CNS barrier models. Isolated endothelial cells were cultured to expand the cellular yield and then passaged onto cell culture inserts for further investigation. Cell culture conditions were optimised using commercially available reagents and the resulting barrier-forming endothelial monolayers were characterised by functional permeability experiments and in vitro phenotyping by immunocytochemistry and western blotting. Using a combination of modified handling techniques and cell culture conditions, we have established and optimised a protocol for the in vitro culture of brain and, for the first time in rat, spinal cord endothelial cells. High yields of both CNS

Coordination of Septate Junctions Assembly and Completion of Cytokinesis in Proliferative Epithelial Tissues.

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Daniel, Emeline; Daudé, Marion; Kolotuev, Irina; Charish, Kristi; Auld, Vanessa; Le Borgne, Roland

2018-05-07

How permeability barrier function is maintained when epithelial cells divide is largely unknown. Here, we have investigated how the bicellular septate junctions (BSJs) and tricellular septate junctions (TSJs) are remodeled throughout completion of cytokinesis in Drosophila epithelia. We report that, following cytokinetic ring constriction, the midbody assembles, matures within SJs, and is displaced basally in two phases. In a first slow phase, the neighboring cells remain connected to the dividing cells by means of SJ-containing membrane protrusions pointing to the maturing midbody. Fluorescence recovery after photobleaching (FRAP) experiments revealed that SJs within the membrane protrusions correspond to the old SJs that were present prior to cytokinesis. In contrast, new SJs are assembled below the adherens junctions and spread basally to build a new belt of SJs in a manner analogous to a conveyor belt. Loss of function of a core BSJ component, the Na+/K+-ATPase pump Nervana 2 subunit, revealed that the apical-to-basal spread of BSJs drives the basal displacement of the midbody. In contrast, loss of the TSJ protein Bark beetle indicated that remodeling of TSJs is rate limiting and slowed down midbody migration. In the second phase, once the belt of SJs is assembled, the basal displacement of the midbody is accelerated and ultimately leads to abscission. This last step is temporally uncoupled from the remodeling of SJs. We propose that cytokinesis in epithelia involves the coordinated polarized assembly and remodeling of SJs both in the dividing cell and its neighbors to ensure the maintenance of permeability barrier integrity in proliferative epithelia. Copyright © 2018 Elsevier Ltd. All rights reserved.

Laboratory study on sequenced permeable reactive barrier remediation for landfill leachate-contaminated groundwater

International Nuclear Information System (INIS)

Dong Jun; Zhao Yongsheng; Zhang Weihong; Hong Mei

2009-01-01

Permeable reactive barrier (PRB) was a promising technology for groundwater remediation. Landfill leachate-polluted groundwater riches in various hazardous contaminants. Two lab-scale reactors (reactors A and B) were designed for studying the feasibility of PRB to remedy the landfill leachate-polluted groundwater. Zero valent iron (ZVI) and the mixture of ZVI and zeolites constitute the first section of the reactors A and B, respectively; the second section of two reactors consists of oxygen releasing compounds (ORCs). Experimental results indicated that BOD 5 /COD increased from initial 0.32 up to average 0.61 and 0.6 through reactors A and B, respectively. Removal efficiency of mixed media for pollutants was higher than that of single media (ZVI only). Zeolites exhibited selective removal of Zn, Mn, Mg, Cd, Sr, and NH 4 + , and removal efficiency was 97.2%, 99.6%, 95.9%, 90.5% and 97.4%, respectively. The maximum DO concentration of reactors A and B were 7.64 and 6.78 mg/L, respectively, while the water flowed through the ORC. Therefore, sequenced PRB system was effective and was proposed as an alternative method to remedy polluted groundwater by landfill leachate

Identifiability of location and magnitude of flow barriers in slightly compressible flow

NARCIS (Netherlands)

Kahrobaei, S.; Mansoori Habib Abadi, M.; Joosten, G.J.P.; Hof, Van den P.M.J.; Jansen, J.D.

2015-01-01

Classic identifiability analysis of flow barriers in incompressible single-phase flow reveals that it is not possible to identify the location and permeability of low-permeability barriers from production data (wellbore pressures and rates), and that only averaged reservoir properties in between

Identifiability of location and magnitude of flow barriers in slightly compressible flow

NARCIS (Netherlands)

Kahrobaei, S.; Mansoori Habib Abadi, M.; Joosten, G.J.P.; Van den Hof, P.; Jansen, J.D.

2016-01-01

Classic identifiability analysis of flow barriers in incompressible single-phase flow reveals that it is not possible to identify the location and permeability of low-permeability barriers from production data (wellbore pressures and rates), and that only averaged reservoir properties in between

Vertical barriers with increased sorption capacities

International Nuclear Information System (INIS)

Bradl, H.B.

1997-01-01

Vertical barriers are commonly used for the containment of contaminated areas. Due to the very small permeability of the barrier material which is usually in the order of magnitude of 10-10 m/s or less the advective contaminant transport can be more or less neglected. Nevertheless, there will always be a diffusive contaminant transport through the barrier which is caused by the concentration gradient. Investigations have been made to increase the sorption capacity of the barrier material by adding substances such as organoclays, zeolites, inorganic oxides and fly ashes. The contaminants taken into account where heavy metals (Pb) and for organic contaminants Toluole and Phenantrene. The paper presents results of model calculations and experiments. As a result, barrier materials can be designed 'tailor-made' depending on the individual contaminant range of each site (e.g. landfills, gasworks etc.). The parameters relevant for construction such as rheological properties, compressive strength and permeability are not affected by the addition of the sorbents

In vitro porcine blood-brain barrier model for permeability studies: pCEL-X software pKa(FLUX) method for aqueous boundary layer correction and detailed data analysis.

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Yusof, Siti R; Avdeef, Alex; Abbott, N Joan

2014-12-18

In vitro blood-brain barrier (BBB) models from primary brain endothelial cells can closely resemble the in vivo BBB, offering valuable models to assay BBB functions and to screen potential central nervous system drugs. We have recently developed an in vitro BBB model using primary porcine brain endothelial cells. The model shows expression of tight junction proteins and high transendothelial electrical resistance, evidence for a restrictive paracellular pathway. Validation studies using small drug-like compounds demonstrated functional uptake and efflux transporters, showing the suitability of the model to assay drug permeability. However, one limitation of in vitro model permeability measurement is the presence of the aqueous boundary layer (ABL) resulting from inefficient stirring during the permeability assay. The ABL can be a rate-limiting step in permeation, particularly for lipophilic compounds, causing underestimation of the permeability. If the ABL effect is ignored, the permeability measured in vitro will not reflect the permeability in vivo. To address the issue, we explored the combination of in vitro permeability measurement using our porcine model with the pKa(FLUX) method in pCEL-X software to correct for the ABL effect and allow a detailed analysis of in vitro (transendothelial) permeability data, Papp. Published Papp using porcine models generated by our group and other groups are also analyzed. From the Papp, intrinsic transcellular permeability (P0) is derived by simultaneous refinement using a weighted nonlinear regression, taking into account permeability through the ABL, paracellular permeability and filter restrictions on permeation. The in vitro P0 derived for 22 compounds (35 measurements) showed good correlation with P0 derived from in situ brain perfusion data (r(2)=0.61). The analysis also gave evidence for carrier-mediated uptake of naloxone, propranolol and vinblastine. The combination of the in vitro porcine model and the software

The intestinal barrier function and its involvement in digestive disease

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Eloísa Salvo-Romero

2015-11-01

Full Text Available The gastrointestinal mucosal surface is lined with epithelial cells representing an effective barrier made up with intercellular junctions that separate the inner and the outer environments, and block the passage of potentially harmful substances. However, epithelial cells are also responsible for the absorption of nutrients and electrolytes, hence a semipermeable barrier is required that selectively allows a number of substances in while keeping others out. To this end, the intestine developed the "intestinal barrier function", a defensive system involving various elements, both intra- and extracellular, that work in a coordinated way to impede the passage of antigens, toxins, and microbial byproducts, and simultaneously preserves the correct development of the epithelial barrier, the immune system, and the acquisition of tolerance against dietary antigens and the intestinal microbiota. Disturbances in the mechanisms of the barrier function favor the development of exaggerated immune responses; while exact implications remain unknown, changes in intestinal barrier function have been associated with the development of inflammatory conditions in the gastrointestinal tract. This review details de various elements of the intestinal barrier function, and the key molecular and cellular changes described for gastrointestinal diseases associated with dysfunction in this defensive mechanism.

Impact of copper oxide nanomaterials on differentiated and undifferentiated Caco-2 intestinal epithelial cells; assessment of cytotoxicity, barrier integrity, cytokine production and nanomaterial penetration.

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Ude, Victor C; Brown, David M; Viale, Luca; Kanase, Nilesh; Stone, Vicki; Johnston, Helinor J

2017-08-23

Copper oxide nanomaterials (CuO NMs) are exploited in a diverse array of products including antimicrobials, inks, cosmetics, textiles and food contact materials. There is therefore a need to assess the toxicity of CuO NMs to the gastrointestinal (GI) tract since exposure could occur via direct oral ingestion, mucocillary clearance (following inhalation) or hand to mouth contact. Undifferentiated Caco-2 intestinal cells were exposed to CuO NMs (10 nm) at concentrations ranging from 0.37 to 78.13 μg/cm 2 Cu (equivalent to 1.95 to 250 μg/ml) and cell viability assessed 24 h post exposure using the alamar blue assay. The benchmark dose (BMD 20), determined using PROAST software, was identified as 4.44 μg/cm 2 for CuO NMs, and 4.25 μg/cm 2 for copper sulphate (CuSO 4 ), which informed the selection of concentrations for further studies. The differentiation status of cells and the impact of CuO NMs and CuSO 4 on the integrity of the differentiated Caco-2 cell monolayer were assessed by measurement of trans-epithelial electrical resistance (TEER), staining for Zonula occludens-1 (ZO-1) and imaging of cell morphology using scanning electron microscopy (SEM). The impact of CuO NMs and CuSO 4 on the viability of differentiated cells was performed via assessment of cell number (DAPI staining), and visualisation of cell morphology (light microscopy). Interleukin-8 (IL-8) production by undifferentiated and differentiated Caco-2 cells following exposure to CuO NMs and CuSO 4 was determined using an ELISA. The copper concentration in the cell lysate, apical and basolateral compartments were measured with Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES) and used to calculate the apparent permeability coefficient (P app ); a measure of barrier permeability to CuO NMs. For all experiments, CuSO 4 was used as an ionic control. CuO NMs and CuSO 4 caused a concentration dependent decrease in cell viability in undifferentiated cells. CuO NMs and CuSO 4

Octopus microvasculature: permeability to ferritin and carbon.

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Browning, J

1979-01-01

The permeability of Octopus microvasculature was investigated by intravascular injection of carbon and ferritin. Vessels were tight to carbon while ferritin penetrated the pericyte junction, and was found extravascularly 1-2 min after its introduction. Vesicles occurred rarely in pericytes; fenestrae were absent. The discontinuous endothelial layer did not consitute a permeability barrier. The basement membrane, although retarding the movement of ferritin, was permeable to it; carbon did not penetrate the basement membrane. Evidence indicated that ferritin, and thus similarly sized and smaller water soluble materials, traverse the pericyte junction as a result of bulk fluid flow. Comparisons are made with the convective (or junctional) and slower, diffusive (or vesicular) passage of materials known to occur across the endothelium of continuous capillaries in mammals. Previous macrophysiological determinations concerning the permeability of Octopus vessels are questioned in view of these findings. Possible reasons for some major structural differences in the microcirculatory systems of cephalopods and vertebrates are briefly discussed.

Clinical research on high oxygen permeable contact lens used after photorefractive keratectomy surgery

Directory of Open Access Journals (Sweden)

Hao-Jiang Yang

2013-07-01

Full Text Available AIM: To evaluate the outcome of high oxygen permeable contact lens used after photorefractive keratectomy(PRKsurgery.METHODS: Totally 95 patients(190 eyesafter PRK were included. Patients were randomly assigned to wear high oxygen permeable contact lens in one eye and normal lens in the fellow eye after surgery. The subjective symptoms and corneal epithelial status after PRK were evaluated. Uncorrected visual acuity(UCVAand haze were assessed at 6 months after PRK.RESULTS: Complaints of blurred vision, pain and photophobia were statistically more among the normal lens group than high oxygen permeable contact lens group(PPP=0.35. There was no difference in UCVA and haze 6 months after surgery(P=0.55. CONCLUSION: High oxygen permeable contact lens can significantly produce less the corneal irritated symptoms, reduce the discomfort feeling and promote healing of corneal epithelium after PRK.

Lactobacillus rhamnosus GG treatment improves intestinal permeability and modulates inflammatory response and homeostasis of spleen and colon in experimental model of Pseudomonas aeruginosa pneumonia.

Science.gov (United States)

Khailova, Ludmila; Baird, Christine H; Rush, Aubri A; Barnes, Christopher; Wischmeyer, Paul E

2017-12-01

Recent clinical trials and in vivo models demonstrate probiotic administration can reduce occurrence and improve outcome of pneumonia and sepsis, both major clinical challenges worldwide. Potential probiotic benefits include maintenance of gut epithelial barrier homeostasis and prevention of downstream organ dysfunction due to systemic inflammation. However, mechanism(s) of probiotic-mediated protection against pneumonia remain poorly understood. This study evaluated potential mechanistic targets in the maintenance of gut barrier homeostasis following Lactobacillus rhamnosus GG (LGG) treatment in a mouse model of pneumonia. Studies were performed in 6-8 week old FVB/N mice treated (o.g.) with or without LGG (10 9  CFU/ml) and intratracheally injected with Pseudomonas aeruginosa or saline. At 4, 12, and 24 h post-bacterial treatment spleen and colonic tissue were collected for analysis. Pneumonia significantly increased intestinal permeability and gut claudin-2. LGG significantly attenuated increased gut permeability and claudin-2 following pneumonia back to sham control levels. As mucin expression is key to gut barrier homeostasis we demonstrate that LGG can enhance goblet cell expression and mucin barrier formation versus control pneumonia animals. Further as Muc2 is a key gut mucin, we show LGG corrected deficient Muc2 expression post-pneumonia. Apoptosis increased in both colon and spleen post-pneumonia, and this increase was significantly attenuated by LGG. Concomitantly, LGG corrected pneumonia-mediated loss of cell proliferation in colon and significantly enhanced cell proliferation in spleen. Finally, LGG significantly reduced pro-inflammatory cytokine gene expression in colon and spleen post-pneumonia. These data demonstrate LGG can maintain intestinal barrier homeostasis by enhancing gut mucin expression/barrier formation, reducing apoptosis, and improving cell proliferation. This was accompanied by reduced pro-inflammatory cytokine expression in the

Characterization of a continuous feline mammary epithelial cell line susceptible to feline epitheliotropic viruses.

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Pesavento, Patricia; Liu, Hongwei; Ossiboff, Robert J; Stucker, Karla M; Heymer, Anna; Millon, Lee; Wood, Jason; van der List, Deborah; Parker, John S L

2009-04-01

Mucosal epithelial cells are the primary targets for many common viral pathogens of cats. Viral infection of epithelia can damage or disrupt the epithelial barrier that protects underlying tissues. In vitro cell culture systems are an effective means to study how viruses infect and disrupt epithelial barriers, however no true continuous or immortalized feline epithelial cell culture lines are available. A continuous cell culture of feline mammary epithelial cells (FMEC UCD-04-2) that forms tight junctions with high transepithelial electrical resistance (>2000Omegacm(-1)) 3-4 days after reaching confluence was characterized. In addition, it was shown that FMECs are susceptible to infection with feline calicivirus (FCV), feline herpesvirus (FHV-1), feline coronavirus (FeCoV), and feline panleukopenia virus (FPV). These cells will be useful for studies of feline viral disease and for in vitro studies of feline epithelia.

The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels

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C Lehner

2016-05-01

Full Text Available Tissue barriers function as “gate keepers” between different compartments (usually blood and tissue and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB. By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies.

Artificial neural network models for prediction of intestinal permeability of oligopeptides

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Kim Min-Kook

2007-07-01

Full Text Available Abstract Background Oral delivery is a highly desirable property for candidate drugs under development. Computational modeling could provide a quick and inexpensive way to assess the intestinal permeability of a molecule. Although there have been several studies aimed at predicting the intestinal absorption of chemical compounds, there have been no attempts to predict intestinal permeability on the basis of peptide sequence information. To develop models for predicting the intestinal permeability of peptides, we adopted an artificial neural network as a machine-learning algorithm. The positive control data consisted of intestinal barrier-permeable peptides obtained by the peroral phage display technique, and the negative control data were prepared from random sequences. Results The capacity of our models to make appropriate predictions was validated by statistical indicators including sensitivity, specificity, enrichment curve, and the area under the receiver operating characteristic (ROC curve (the ROC score. The training and test set statistics indicated that our models were of strikingly good quality and could discriminate between permeable and random sequences with a high level of confidence. Conclusion We developed artificial neural network models to predict the intestinal permeabilities of oligopeptides on the basis of peptide sequence information. Both binary and VHSE (principal components score Vectors of Hydrophobic, Steric and Electronic properties descriptors produced statistically significant training models; the models with simple neural network architectures showed slightly greater predictive power than those with complex ones. We anticipate that our models will be applicable to the selection of intestinal barrier-permeable peptides for generating peptide drugs or peptidomimetics.

Evaluation of lung epithelial permeability in the volatile substance abuse using Tc-99m DTPA aerosol scintigraphy

International Nuclear Information System (INIS)

Cayir, D.; Demirel, K.; Korkmaz, M.; Koca, G.

2011-01-01

Chronic inhalant use is associated with significant toxic effects, including neurological, renal, hepatic, and pulmonary damage. However, there is a paucity of reports regarding respiratory complications in inhalant abusers. The aim of this study was to evaluate pulmonary epithelial permeability in the volatile substance abuse (VSA) using technetium-99m-labeled diethylenetriamine pentaacetic acid (Tc-99m DTPA) aerosol scintigraphy. This study included 18 patients with volatile substance abuse and 18 volunteer controls. All of patients and controls were smokers. Tc-99m DTPA aerosol scintigraphy was performed in all cases. Time-activity curves from each lung were generated and clearance half-time (T 1/2 ) of Tc-99m DTPA were calculated. T 1/2 of whole lung was calculated as a mean of the T 1/2 of left and right lung. The T 1/2 values of Tc-99m DTPA clearance in the substance abusers were significantly decreased as compared to the control group with respective mean values of 28.86±8.44, and 62.14±26.12 min (p=0.001). It was seen Tc-99m DTPA clearance from lung was faster as the duration of substance abuse was increased. Tc-99m DTPA pulmonary clearance is markedly accelerated in the volatile substance abuse. This suggests that inhalant abuse of substance may produce abnormalities in pulmonary alveolo-capillary membrane function. (author)

Evaluation of lung epithelial permeability in the volatile substance abuse using Tc-99m DTPA aerosol scintigraphy.

Science.gov (United States)

Cayir, Derya; Demirel, Koray; Korkmaz, Meliha; Koca, Gokhan

2011-10-01

Chronic inhalant use is associated with significant toxic effects, including neurological, renal, hepatic, and pulmonary damage. However, there is a paucity of reports regarding respiratory complications in inhalant abusers. The aim of this study was to evaluate pulmonary epithelial permeability in the volatile substance abuse (VSA) using Tc-99m DTPA aerosol scintigraphy. This study included 18 patients with volatile substance abuse and 18 volunteer controls. All of patients and controls were smokers. Tc-99m DTPA aerosol scintigraphy was performed in all cases. Time-activity curves from each lung were generated and clearance half-time (T(1/2)) of Tc-99m DTPA were calculated. T(1/2) of whole lung was calculated as a mean of the T(1/2) of left and right lung. The T(1/2) values of Tc-99m DTPA clearance in the substance abusers were significantly decreased as compared to the control group with respective mean values of 28.86 ± 8.44, and 62.14 ± 26.12 min (p = 0.001). It was seen Tc-99m DTPA clearance from lung was faster as the duration of substance abuse was increased. Tc-99m DTPA pulmonary clearance is markedly accelerated in the volatile substance abuse. This suggests that inhalant abuse of substance may produce abnormalities in pulmonary alveolo-capillary membrane function.

Utilization of coal/biomass fly ash and bentonite as a low permeability barrier for the containment of acid-generating mine tailings

International Nuclear Information System (INIS)

Penney, K.; Mohamedelhassan, E.; Catalan, L.J.J.

2009-01-01

The control and treatment of acid mine drainage (AMD) in decommissioned mine sites is a major environmental challenge. In general, AMD has a low pH, high acidity, and elevated concentrations of heavy metals. This study investigated the use of coal/biomass fly ash (CBFA) and CBFA/bentonite mixtures as a low permeability seal to contain acid generating mine tailings and treat AMD. Although pure CBFA is effective as a reactive barrier to treat most toxic metals in AMD, its initial hydraulic conductivity exceeds the maximum regulatory requirement of 1 x 10 -7 cm/s. Therefore, 3 cases were investigated, notably CBFA only; CBFA amended with low percentages of bentonite; and layering of CBFA and CBFA amended with bentonite. Practical geoenvironmental applications for low permeability CBFA or bentonite/CBFA mixtures include a cap overlying reactive mine tailings, a containment pond liner, and a core in containment dams and dykes. Mixing 10 per cent by mass bentonite with CBFA decreased the hydraulic conductivity to 1 x 10 -7 cm/s or less throughout the entire permeation by water and AMD. The installation of a layer of pure CBFA upstream of the bentonite/CBFA mixture resulted in a further decrease in hydraulic conductivity over time by preventing the collapse of the bentonite double layer and promoting precipitation of gypsum and ettringite in the CBFA layer. The effluent from all tested bentonite/CBFA barriers met the regulatory requirements for chemical parameters, except for aluminum which was leached from the CBFA. 14 refs., 3 tabs., 10 figs.

Atomic layer deposition of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/TiO{sub 2} barrier coatings to reduce the water vapour permeability of polyetheretherketone

Energy Technology Data Exchange (ETDEWEB)

Ahmadzada, Tamkin, E-mail: tahm4852@uni.sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); McKenzie, David R.; James, Natalie L.; Yin, Yongbai [School of Physics, University of Sydney, NSW 2006 (Australia); Li, Qing [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia)

2015-09-30

We demonstrate significantly enhanced barrier properties of polyetheretherketone (PEEK) against water vapour penetration by depositing Al{sub 2}O{sub 3} or Al{sub 2}O{sub 3}/TiO{sub 2} nanofilms grown by atomic layer deposition (ALD). Nanoindentation analysis revealed good adhesion strength of a bilayer Al{sub 2}O{sub 3}/TiO{sub 2} coating to PEEK, while the single layer Al{sub 2}O{sub 3} coating displayed flaking and delamination. We identified three critical design parameters for achieving the optimum barrier properties of ALD Al{sub 2}O{sub 3}/TiO{sub 2} coatings on PEEK. These are a minimum total thickness dependent on the required water vapour transmission rate, the use of an Al{sub 2}O{sub 3}/TiO{sub 2} bilayer coating and the application of the coating to both sides of the PEEK film. Using these design parameters, we achieved a reduction in moisture permeability of PEEK of over two orders of magnitude while maintaining good adhesion strength of the polymer–thin film system. - Highlights: • Atomic layer deposition of Al{sub 2}O{sub 3}/TiO{sub 2} coatings reduced water vapour permeability. • Bilayer coatings reduced the permeability more than single layer coatings. • Bilayer coatings displayed higher adhesion strength than the single layer coatings. • Double-sided coatings performed better than single-sided coatings. • Correlation was found between total thickness and reduced water vapour permeability.

Examination of blood-brain barrier permeability in dementia of the Alzheimer type with [68Ga]EDTA and positron emission tomography

International Nuclear Information System (INIS)

Schlageter, N.L.; Carson, R.E.; Rapoport, S.I.

1987-01-01

Positron emission tomography with [ 68 Ga]ethylenediaminetetraacetic acid ([ 68 Ga]EDTA) was used to examine the integrity of the blood-brain barrier (BBB) in five patients with dementia of the Alzheimer type and in five healthy age-matched controls. Within a scanning time of 90 min, there was no evidence that measurable intravascular tracer entered the brain in either the dementia or the control group. An upper limit for the cerebrovascular permeability-surface area product of [68Ga]EDTA was estimated as 2 X 10(-6) s-1 in both groups. The results provide no evidence for breakdown of the BBB in patients with dementia of the Alzheimer type

Examination of blood-brain barrier permeability in dementia of the Alzheimer type with [68Ga]EDTA and positron emission tomography.

Science.gov (United States)

Schlageter, N L; Carson, R E; Rapoport, S I

1987-02-01

Positron emission tomography with [68Ga]ethylenediaminetetraacetic acid ([68Ga]EDTA) was used to examine the integrity of the blood-brain barrier (BBB) in five patients with dementia of the Alzheimer type and in five healthy age-matched controls. Within a scanning time of 90 min, there was no evidence that measurable intravascular tracer entered the brain in either the dementia or the control group. An upper limit for the cerebrovascular permeability-surface area product of [68Ga]EDTA was estimated as 2 X 10(-6) s-1 in both groups. The results provide no evidence for breakdown of the BBB in patients with dementia of the Alzheimer type.

Examination of blood-brain barrier permeability in dementia of the Alzheimer type with (68Ga)EDTA and positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Schlageter, N.L.; Carson, R.E.; Rapoport, S.I.

1987-02-01

Positron emission tomography with (/sup 68/Ga)ethylenediaminetetraacetic acid ((/sup 68/Ga)EDTA) was used to examine the integrity of the blood-brain barrier (BBB) in five patients with dementia of the Alzheimer type and in five healthy age-matched controls. Within a scanning time of 90 min, there was no evidence that measurable intravascular tracer entered the brain in either the dementia or the control group. An upper limit for the cerebrovascular permeability-surface area product of (68Ga)EDTA was estimated as 2 X 10(-6) s-1 in both groups. The results provide no evidence for breakdown of the BBB in patients with dementia of the Alzheimer type.

Minoxidil sulfate induced the increase in blood-brain tumor barrier permeability through ROS/RhoA/PI3K/PKB signaling pathway.

Science.gov (United States)

Gu, Yan-ting; Xue, Yi-xue; Wang, Yan-feng; Wang, Jin-hui; Chen, Xia; ShangGuan, Qian-ru; Lian, Yan; Zhong, Lei; Meng, Ying-nan

2013-12-01

Adenosine 5'-triphosphate-sensitive potassium channel (KATP channel) activator, minoxidil sulfate (MS), can selectively increase the permeability of the blood-tumor barrier (BTB); however, the mechanism by which this occurs is still under investigation. Using a rat brain glioma (C6) model, we first examined the expression levels of occludin and claudin-5 at different time points after intracarotid infusion of MS (30 μg/kg/min) by western blotting. Compared to MS treatment for 0 min group, the protein expression levels of occludin and claudin-5 in brain tumor tissue of rats showed no changes within 1 h and began to decrease significantly after 2 h of MS infusion. Based on these findings, we then used an in vitro BTB model and selective inhibitors of diverse signaling pathways to investigate whether reactive oxygen species (ROS)/RhoA/PI3K/PKB pathway play a key role in the process of the increase of BTB permeability induced by MS. The inhibitor of ROS or RhoA or PI3K or PKB significantly attenuated the expression of tight junction (TJ) protein and the increase of the BTB permeability after 2 h of MS treatment. In addition, the significant increases in RhoA activity and PKB phosphorylation after MS administration were observed, which were partly inhibited by N-2-mercaptopropionyl glycine (MPG) or C3 exoenzyme or LY294002 pretreatment. The present study indicates that the activation of signaling cascades involving ROS/RhoA/PI3K/PKB in BTB was required for the increase of BTB permeability induced by MS. Taken together, all of these results suggested that MS might increase BTB permeability in a time-dependent manner by down-regulating TJ protein expression and this effect could be related to ROS/RhoA/PI3K/PKB signal pathway. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sensing of Vascular Permeability in Inflamed Vessel of Live Animal

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Sang A Park

2018-01-01

Full Text Available Increase in vascular permeability is a conclusive response in the progress of inflammation. Under controlled conditions, leukocytes are known to migrate across the vascular barriers to the sites of inflammation without severe vascular rupture. However, when inflammatory state becomes excessive, the leakage of blood components may occur and can be lethal. Basically, vascular permeability can be analyzed based on the intensity of blood outflow. To evaluate the amount and rate of leakage in live mice, we performed cremaster muscle exteriorization to visualize blood flow and neutrophil migration. Using two-photon intravital microscopy of the exteriorized cremaster muscle venules, we found that vascular barrier function is transiently and locally disrupted in the early stage of inflammatory condition induced by N-formylmethionyl-leucyl-phenylalanine (fMLP. Measurement of the concentration of intravenously (i.v. injected Texas Red dextran inside and outside the vessels resulted in clear visualization of real-time increases in transient and local vascular permeability increase in real-time manner. We successfully demonstrated repeated leakage from a target site on a blood vessel in association with increasing severity of inflammation. Therefore, compared to other methods, two-photon intravital microscopy more accurately visualizes and quantifies vascular permeability even in a small part of blood vessels in live animals in real time.

Characterizing microbiota-independent effects of oligosaccharides on intestinal epithelial cells: insight into the role of structure and size : Structure-activity relationships of non-digestible oligosaccharides.

Science.gov (United States)

Akbari, Peyman; Fink-Gremmels, Johanna; Willems, Rianne H A M; Difilippo, Elisabetta; Schols, Henk A; Schoterman, Margriet H C; Garssen, Johan; Braber, Saskia

2017-08-01

The direct effects of galacto-oligosaccharides (GOS), including Vivinal ® GOS syrup (VGOS) and purified Vivinal ® GOS (PGOS), on the epithelial integrity and corresponding interleukin-8 (IL-8/CXCL8) release were examined in a Caco-2 cell model for intestinal barrier dysfunction. To investigate structure-activity relationships, the effects of individual DP fractions of VGOS were evaluated. Moreover, the obtained results with GOS were compared with Caco-2 monolayers incubated with fructo-oligosaccharides (FOS) and inulin. Caco-2 monolayers were pretreated (24 h) with or without specific oligosaccharides or DP fractions of VGOS (DP2 to DP6) before being exposed for 12 or 24 h to the fungal toxin deoxynivalenol (DON). Transepithelial electrical resistance and lucifer yellow permeability were measured to investigate barrier integrity. A calcium switch assay was used to study the reassembly of tight junction proteins. Release of CXCL8, a typical marker for inflammation, was quantified by ELISA. In comparison with PGOS, FOS and inulin, VGOS showed the most pronounced protective effect on the DON-induced impairment of the monolayer integrity, acceleration of the tight junction reassembly and the subsequent CXCL8 release. DP2 and DP3 in concentrations occurring in VGOS prevented the DON-induced epithelial barrier disruption, which could be related to their high prevalence in VGOS. However, no effects of the separate DP GOS fractions were observed on CXCL8 release. This comparative study demonstrates the direct, microbiota-independent effects of oligosaccharides on the intestinal barrier function and shows the differences between individual galacto- and fructo-oligosaccharides. This microbiota-independent effect of oligosaccharides depends on the oligosaccharide structure, DP length and concentration.

Assessment of solid reactive mixtures for the development of biological permeable reactive barriers

International Nuclear Information System (INIS)

Pagnanelli, Francesca; Viggi, Carolina Cruz; Mainelli, Sara; Toro, Luigi

2009-01-01

Solid reactive mixtures were tested as filling material for the development of biological permeable reactive barriers for the treatment of heavy metals contaminated waters. Mixture selection was performed by taking into account the different mechanisms operating in sulphate and cadmium removal with particular attention to bioprecipitation and sorption onto the organic matrices in the mixtures. Suspensions of eight reactive mixtures were tested for sulphate removal (initial concentration 3 g L -1 ). Each mixture was made up of four main functional components: a mix of organic sources for bacterial growth, a neutralizing agent, a porous medium and zero-valent iron. The best mixture among the tested ones (M8: 6% leaves, 9% compost, 3% zero-valent iron, 30% silica sand, 30% perlite, 22% limestone) presented optimal conditions for SRB growth (pH 7.8 ± 0.1; E h = -410 ± 5 mV) and 83% sulphate removal in 22 days (25% due to bioreduction, 32% due to sorption onto compost and 20% onto leaves). M8 mixture allowed the complete abatement of cadmium with a significant contribution of sorption over bioprecipitation (6% Cd removal due to SRB activity). Sorption properties, characterised by potentiometric titrations and related modelling, were mainly due to carboxylic sites of organic components used in reactive mixtures.

Hydrogen sulfide metabolism regulates endothelial solute barrier function

Directory of Open Access Journals (Sweden)

Shuai Yuan

2016-10-01

Full Text Available Hydrogen sulfide (H2S is an important gaseous signaling molecule in the cardiovascular system. In addition to free H2S, H2S can be oxidized to polysulfide which can be biologically active. Since the impact of H2S on endothelial solute barrier function is not known, we sought to determine whether H2S and its various metabolites affect endothelial permeability. In vitro permeability was evaluated using albumin flux and transendothelial electrical resistance. Different H2S donors were used to examine the effects of exogenous H2S. To evaluate the role of endogenous H2S, mouse aortic endothelial cells (MAECs were isolated from wild type mice and mice lacking cystathionine γ-lyase (CSE, a predominant source of H2S in endothelial cells. In vivo permeability was evaluated using the Miles assay. We observed that polysulfide donors induced rapid albumin flux across endothelium. Comparatively, free sulfide donors increased permeability only with higher concentrations and at later time points. Increased solute permeability was associated with disruption of endothelial junction proteins claudin 5 and VE-cadherin, along with enhanced actin stress fiber formation. Importantly, sulfide donors that increase permeability elicited a preferential increase in polysulfide levels within endothelium. Similarly, CSE deficient MAECs showed enhanced solute barrier function along with reduced endogenous bound sulfane sulfur. CSE siRNA knockdown also enhanced endothelial junction structures with increased claudin 5 protein expression. In vivo, CSE genetic deficiency significantly blunted VEGF induced hyperpermeability revealing an important role of the enzyme for barrier function. In summary, endothelial solute permeability is critically regulated via exogenous and endogenous sulfide bioavailability with a prominent role of polysulfides.

An Experimental Study of Micron-Size Zero-Valent Iron Emplacement in Permeable Porous Media Using Polymer-Enhanced Fluids

Energy Technology Data Exchange (ETDEWEB)

Oostrom, Mart; Wietsma, Thomas W.; Covert, Matthew A.; Vermeul, Vince R.

2005-12-22

At the Hanford Site, an extensive In Situ Redox Manipulation (ISRM) permeable reactive barrier was installed to prevent chromate from reaching the Columbia River. However, chromium has been detected in several wells, indicating a premature loss of the reductive capacity in the aquifer. One possible cause for premature chromate breakthrough is associated with the presence of high-permeability zones in the aquifer. In these zones, groundwater moves relatively fast and is able to oxidize iron more rapidly. There is also a possibility that the high-permeability flow paths are deficient in reducing equivalents (e.g. reactive iron), required for barrier performance. One way enhancement of the current barrier reductive capacity can be achieved is by the addition of micron-scale zero-valent iron to the high-permeability zones within the aquifer. The potential emplacement of zero-valent iron (Fe0) into high-permeability Hanford sediments (Ringold Unit E gravels) using shear-thinning fluids containing polymers was investigated in three-dimensional wedge-shaped aquifer models. Polymers were used to create a suspension viscous enough to keep the Fe0 in solution for extended time periods to improve colloid movement into the porous media without causing a permanent detrimental decrease in hydraulic conductivity. Porous media were packed in the wedge-shaped flow cell to create either a heterogeneous layered system with a high-permeability zone in between two low-permeability zones or a high-permeability channel surrounded by low-permeability materials. The injection flow rate, polymer type, polymer concentration, and injected pore volumes were determined based on preliminary short- and long-column experiments.

Dietary soya saponins increase gut permeability and play a key role in the onset of soyabean-induced enteritis in Atlantic salmon ( Salmo salar L.).

Science.gov (United States)

Knudsen, David; Jutfelt, Fredrik; Sundh, Henrik; Sundell, Kristina; Koppe, Wolfgang; Frøkiaer, Hanne

2008-07-01

Saponins are naturally occurring amphiphilic molecules and have been associated with many biological activities. The aim of the present study was to investigate whether soya saponins trigger the onset of soyabean-induced enteritis in Atlantic salmon (Salmo salar L.), and to examine if dietary soya saponins increase the epithelial permeability of the distal intestine in Atlantic salmon. Seven experimental diets containing different levels of soya saponins were fed to seawater-adapted Atlantic salmon for 53 d. The diets included a fishmeal-based control diet, two fishmeal-based diets with different levels of added soya saponins, one diet containing 25% lupin kernel meal, two diets based on 25% lupin kernel meal with different levels of added soya saponins, and one diet containing 25% defatted soyabean meal. The effect on intestinal morphology, intestinal epithelial permeability and faecal DM content was examined. Fish fed 25% defatted soyabean meal displayed severe enteritis, whereas fish fed 25% lupin kernel meal had normal intestinal morphology. The combination of soya saponins and fishmeal did not induce morphological changes but fish fed soya saponins in combination with lupin kernel meal displayed significant enteritis. Increased epithelial permeability was observed in fish fed 25% defatted soyabean meal and in fish fed soya saponin concentrate independent of the protein source in the feed. The study demonstrates that soya saponins, in combination with one or several unidentified components present in legumes, induce an inflammatory reaction in the distal intestine of Atlantic salmon. Soya saponins increase the intestinal epithelial permeability but do not, per se, induce enteritis.

Endothelial cell permeability to water and antipyrine

International Nuclear Information System (INIS)

Garrick, R.A.

1986-01-01

The endothelium provides a structural barrier between plasma constituents and the tissues. The permeability characteristics of the the endothelial cells regulate the transcellular movement of materials across this barrier while other movement is paracellular. In this study the permeability of the endothelial cells to tritiated water ( 3 HHO) and 14 C-labeled antipyrine (AP) was investigated. The cells were isolated non-enzymatically from calf pulmonary artery and were maintained in culture and used between the seventh and fifteenth passage. The cells were removed from the T-flasks with a rubber policeman, titurated with a 22g needle and centrifuged. The cells were mixed with an extracellular marker, drawn into polyethylene tubing and packed by centrifugation for use in the linear diffusion technique. All measurements were made at 37 C. The diffusion coefficients for 3 HHO through the packed cells (D), the intracellular material (D 2 ), and the extracellular material (D 1 ) were 0.682, 0.932 and 2.45 x 10 -5 cm 2 s -1 and for AP were 0.273, 0.355 and 1.13 x 10 -5 cm 2 s -1 respectively. The permeability coefficient calculated by the series-parallel pathway model for 3 HHO was higher than that for AP and for both 3 HHO and AP were lower than those calculated for isolated lung cells and erythrocytes

The role of multidrug resistance protein (MRP-1) as an active efflux transporter on blood-brain barrier (BBB) permeability.

Science.gov (United States)

Lingineni, Karthik; Belekar, Vilas; Tangadpalliwar, Sujit R; Garg, Prabha

2017-05-01

Drugs acting on central nervous system (CNS) may take longer duration to reach the market as these compounds have a higher attrition rate in clinical trials due to the complexity of the brain, side effects, and poor blood-brain barrier (BBB) permeability compared to non-CNS-acting compounds. The roles of active efflux transporters with BBB are still unclear. The aim of the present work was to develop a predictive model for BBB permeability that includes the MRP-1 transporter, which is considered as an active efflux transporter. A support vector machine model was developed for the classification of MRP-1 substrates and non-substrates, which was validated with an external data set and Y-randomization method. An artificial neural network model has been developed to evaluate the role of MRP-1 on BBB permeation. A total of nine descriptors were selected, which included molecular weight, topological polar surface area, ClogP, number of hydrogen bond donors, number of hydrogen bond acceptors, number of rotatable bonds, P-gp, BCRP, and MRP-1 substrate probabilities for model development. We identified 5 molecules that fulfilled all criteria required for passive permeation of BBB, but they all have a low logBB value, which suggested that the molecules were effluxed by the MRP-1 transporter.

The effect of high energy electron irradiation on blood-brain barrier permeability to haloperidol and stobadin in rats

Energy Technology Data Exchange (ETDEWEB)

Trnovec, T; Kallay, Z [Komenskeho Univ., Bratislava (Czechoslovakia). Inst. of Preventive and Clinical Medicine; Volenec, K [Karlova Univ., Hradec Kralove (Czechoslovakia). Lekarska Fakulta; Bezek, S; Durisova, M; Scasnar, V; Kubu, M [Slovenska Akademia Vied, Bratislava (Czechoslovakia). Ustav Experimentalnej Farmakologie; Svoboda, V [Medical Academy J.E. Purkyne, Hradec Kralove (Czechoslovakia)

1991-10-01

The heads of rats were irradiated by 4 MeV electrons in doses 90, 180, and 360 Gy. The observed times of deaths ranged 120-600, 60-420, and 150-370 min after 90, 180, and 360 Gy, respectively. A dose dependent decrease of the brain uptake index of haloperidol was observed 1 and 3 h post radiation. On the other hand an increased brain uptake index was found for stobadin after head irradiation with doses of 180 and 360 Gy. Regional cerebral blood flow, blood pressure, and heart rate were not significantly altered in the period following irradiation with 180 Gy. The observed changes in blood-brain barrier (BBB) permeability seem to be the result of the damaged function of morphological structures forming the BBB rather than altered regional blood flow. (orig.).

Noise alters guinea pig's blood-labyrinth barrier ultrastructure and permeability along with a decrease of cochlear Claudin-5 and Occludin.

Science.gov (United States)

Wu, Yong-Xiang; Zhu, Guo-Xia; Liu, Xin-Qin; Sun, Fei; Zhou, Ke; Wang, Shuang; Wang, Chun-Mei; Jia, Jin-Wen; Song, Jian-Tao; Lu, Lian-Jun

2014-12-24

Noise exposure (NE) is a severe modern health hazard that induces hearing impairment. However, the noise-induced ultrastructural changes of blood-labyrinth barrier (BLB) and the potential involvements of tight junction proteins (TJP) remain inconclusive. We investigated the effects of NE on not only the ultrastructure of cochlea and permeability of BLB but also the expression of TJP within the guinea pig cochlea. Male albino guinea pigs were exposed to white noise for 4 h or 2 consecutive days (115 dB sound pressure level, 6 hours per day) and the hearing impairments and light microscopic change of BLB were evaluated with auditory brainstem responses (ABR) and the cochlear sensory epithelia surface preparation, respectively. The cochlear ultrastructure and BLB permeability after NE 2d were revealed with transmission electron microscope (TEM) and lanthanum nitrate-tracing techniques, respectively. The potential alterations of TJPs Claudin-5 and Occludin were quantified with immunohistochemistry and western blot. NE induced significant hearing impairment and NE 2d contributed to significant outer hair cell (OHC) loss that is most severe in the first row of outer hair cells. Furthermore, the loosen TJ and an obvious leakage of lanthanum nitrate particles beneath the basal lamina were revealed with TEM. Moreover, a dose-dependent decrease of Claudin-5 and Occludin was observed in the cochlea after NE. All these findings suggest that both decrease of Claudin-5 and Occludin and increased BLB permeability are involved in the pathologic process of noise-induced hearing impairment; however, the causal relationship and underlying mechanisms should be further investigated.

Water permeability of Na+-K+-2Cl- cotransporters in mammalian epithelial cells

DEFF Research Database (Denmark)

Hamann, Steffen; Herrera-Perez, José Jaime; Bundgaard, Magnus

2005-01-01

Water transport properties of the Na+-K+-2Cl- cotransporter (NKCC) were studied in cultures of pigmented epithelial cells (PE) from the ciliary body of the eye. Here, the membrane that faces upwards contains NKCCs and can be subjected to rapid changes in bathing solution composition and osmolarity...

Barriers to Liposomal Gene Delivery: from Application Site to the Target.

Science.gov (United States)

Saffari, Mostafa; Moghimi, Hamid Reza; Dass, Crispin R

2016-01-01

Gene therapy is a therapeutic approach to deliver genetic material into cells to alter their function in entire organism. One promising form of gene delivery system (DDS) is liposomes. The success of liposome-mediated gene delivery is a multifactorial issue and well-designed liposomal systems might lead to optimized gene transfection particularly in vivo. Liposomal gene delivery systems face different barriers from their site of application to their target, which is inside the cells. These barriers include presystemic obstacles (epithelial barriers), systemic barriers in blood circulation and cellular barriers. Epithelial barriers differ depending on the route of administration. Systemic barriers include enzymatic degradation, binding and opsonisation. Both of these barriers can act as limiting hurdles that genetic material and their vector should overcome before reaching the cells. Finally liposomes should overcome cellular barriers that include cell entrance, endosomal escape and nuclear uptake. These barriers and their impact on liposomal gene delivery will be discussed in this review.

Phosphatidylcholine reverses ethanol-induced increase in transepithelial endotoxin permeability and abolishes transepithelial leukocyte activation

DEFF Research Database (Denmark)

Mitscherling, K.; Volynets, V.; Parlesak, Alexandr

2009-01-01

BACKGROUND: Chronic alcohol abuse increases both intestinal bacterial overgrowth and intestinal permeability to macromolecules. Intestinal permeability of endotoxin, a component of the outer cell membrane of Gram-negative bacteria, plays a crucial role in the development of alcohol-induced liver...... disease (ALD). As impaired bile flow leads to endotoxemia and the bile component phosphatidylcholine (PC) is therapeutically active in ALD, we tested the hypothesis that conjugated primary bile salts (CPBS) and PC inhibit ethanol-enhanced transepithelial permeability of endotoxin and the subsequent...... transepithelial activation of human leukocytes. METHODS: For this purpose, we used a model in which intestinal epithelial cells (Caco-2) were basolaterally cocultivated with mononuclear leukocytes. Cells were challenged apically with endotoxin from Escherichia coli K12 and were incubated with or without...

ROS-activated calcium signaling mechanisms regulating endothelial barrier function.

Science.gov (United States)

Di, Anke; Mehta, Dolly; Malik, Asrar B

2016-09-01

Increased vascular permeability is a common pathogenic feature in many inflammatory diseases. For example in acute lung injury (ALI) and its most severe form, the acute respiratory distress syndrome (ARDS), lung microvessel endothelia lose their junctional integrity resulting in leakiness of the endothelial barrier and accumulation of protein rich edema. Increased reactive oxygen species (ROS) generated by neutrophils (PMNs) and other inflammatory cells play an important role in increasing endothelial permeability. In essence, multiple inflammatory syndromes are caused by dysfunction and compromise of the barrier properties of the endothelium as a consequence of unregulated acute inflammatory response. This review focuses on the role of ROS signaling in controlling endothelial permeability with particular focus on ALI. We summarize below recent progress in defining signaling events leading to increased endothelial permeability and ALI. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gliadin induces an increase in intestinal permeability and zonulin release by binding to the chemokine receptor CXCR3.

Science.gov (United States)

Lammers, Karen M; Lu, Ruliang; Brownley, Julie; Lu, Bao; Gerard, Craig; Thomas, Karen; Rallabhandi, Prasad; Shea-Donohue, Terez; Tamiz, Amir; Alkan, Sefik; Netzel-Arnett, Sarah; Antalis, Toni; Vogel, Stefanie N; Fasano, Alessio

2008-07-01

Celiac disease is an immune-mediated enteropathy triggered by gliadin, a component of the grain protein gluten. Gliadin induces an MyD88-dependent zonulin release that leads to increased intestinal permeability, a postulated early element in the pathogenesis of celiac disease. We aimed to establish the molecular basis of gliadin interaction with intestinal mucosa leading to intestinal barrier impairment. Alpha-gliadin affinity column was loaded with intestinal mucosal membrane lysates to identify the putative gliadin-binding moiety. In vitro experiments with chemokine receptor CXCR3 transfectants were performed to confirm binding of gliadin and/or 26 overlapping 20mer alpha-gliadin synthetic peptides to the receptor. CXCR3 protein and gene expression were studied in intestinal epithelial cell lines and human biopsy specimens. Gliadin-CXCR3 interaction was further analyzed by immunofluorescence microscopy, laser capture microscopy, real-time reverse-transcription polymerase chain reaction, and immunoprecipitation/Western blot analysis. Ex vivo experiments were performed using C57BL/6 wild-type and CXCR3(-/-) mouse small intestines to measure intestinal permeability and zonulin release. Affinity column and colocalization experiments showed that gliadin binds to CXCR3 and that at least 2 alpha-gliadin 20mer synthetic peptides are involved in this binding. CXCR3 is expressed in mouse and human intestinal epithelia and lamina propria. Mucosal CXCR3 expression was elevated in active celiac disease but returned to baseline levels following implementation of a gluten-free diet. Gliadin induced physical association between CXCR3 and MyD88 in enterocytes. Gliadin increased zonulin release and intestinal permeability in wild-type but not CXCR3(-/-) mouse small intestine. Gliadin binds to CXCR3 and leads to MyD88-dependent zonulin release and increased intestinal permeability.

Protection of the blood-brain barrier by hypercapnia during acute hypertension

International Nuclear Information System (INIS)

Baumbach, G.L.; Mayhan, W.G.; Heistad, D.D.

1986-01-01

The purpose of this study was to examine effects of hypercapnia on susceptibility of the blood-brain barrier to disruption during acute hypertension. Two methods were used to test the hypothesis that cerebral vasodilation during hypercapnia increases disruption of the blood-brain barrier. First, permeability of the blood-brain barrier was measured in anesthetized cats with 125 I-labeled serum albumin. Severe hypertension markedly increased permeability of the blood-brain barrier during normocapnia, but not during hypercapnia. The protective effect of hypercapnia was not dependent on sympathetic nerves. Second, in anesthetized rats, permeability of the barrier was quantitated by clearance of fluorescent dextran. Disruption of the blood-brain barrier during hypertension was decreased by hypercapnia. Because disruption of the blood-brain barrier occurred primarily in pial venules, the authors also measured pial venular diameter and pressure. Acute hypertension increased pial venular pressure and diameter in normocapnic rats. Hypercapnia alone increased pial venular pressure and pial venular diameter, and acute hypertension during hypercapnia further increased venular pressure. The magnitude of increase in pial venular pressure during acute hypertension was significantly less in hypercapnic than in normocapnic rats. They conclude that hypercapnia protects the blood-brain barrier. Possible mechanisms of this effect include attenuation of the incremental increase in pial venular pressure by hypercapnia or a direct effect on the blood-brain barrier not related to venous pressure

Matriptase zymogen supports epithelial development, homeostasis and regeneration

DEFF Research Database (Denmark)

Friis, Stine; Tadeo, Daniel; Le-Gall, Sylvain M.

2017-01-01

Background Matriptase is a membrane serine protease essential for epithelial development, homeostasis, and regeneration, as well as a central orchestrator of pathogenic pericellular signaling in the context of inflammatory and proliferative diseases. Matriptase is an unusual protease in that its...... previously reported for transgenic mice mis-expressing wildtype epidermal matriptase. Equally surprising, mice engineered to express only zymogen-locked endogenous matriptase, unlike matriptase null mice, were viable, developed epithelial barrier function, and regenerated the injured epithelium. Compatible...

[The blood-brain barrier in ageing persons].

Science.gov (United States)

Haaning, Nina; Damsgaard, Else Marie; Moos, Torben

2018-03-26

Brain capillary endothelial cells (BECs) form the ultra-tight blood-brain barrier (BBB). The permeability of the BBB increases with increasing age and neurovascular and neurodegenerative diseases. Major defects of the BBB can be initiated by increased permeability to plasma proteins in small arteriosclerotic arteries and release of proteins from degenerating neurons into the brain extracellular space. These proteins deposit in perivascular spaces, and subsequently negatively influence the BECs leading to decreased expression of barrier proteins. Detection of BBB defects by the use of non-invasive techniques is relevant for clinical use in settings with advanced age and severe brain disorders.

A intervenção da célula epitelial na asma The role of the epithelial cell in asthma

Directory of Open Access Journals (Sweden)

Anabela Mota Pinto

2009-05-01

barrier that separates the external environment from the pulmonary internal environment. It controls the intercellular and trans -cellular permeability and this way the accessibility of the inhaled pathogens to the antigen presenting cells involved in the immuno -inflammatory response. Epithelial cells connected by tight junctions contribute to the barrier function of the airways. They express a poliovirus receiver - related protein (PRR, toll like receptors (TLRs and protease-activated receptors (PARs, which recognize bacterial agents and allergens. Its dysfunction turns them into important sources of inflammatory mediators. The bidirectional interaction between the epithelium and other bronchial wall elements with inhaled particles originates a structure with its own identity, the designated EMTU - Epithelial Mesenchymal Trophic Unit. These observations support a central role for the epithelial cell in chronic inflammation and in the remodelling of the asthmatic process. Infectious diseases and environmental stress can activate different cell receptors and signalling pathways that induce changes in the cell surface modifying their response to future stimulations, namely to other infectious aggressions. The bronchial epithelium has barrier functions with selective permeability; it has metabolic activity producing cytokines and chemokines stimulating the cell’s recruitment and activation, increasing the bronchial reactivity and the remodelling of the airways.

Evaluation of a permeable reactive barrier technology for use at Rocky Flats Environmental Technology Site (RFETS)

International Nuclear Information System (INIS)

Dwyer, Brian P.

2000-01-01

Three reactive materials were evaluated at laboratory scale to identify the optimum treatment reagent for use in a Permeable Reactive Barrier Treatment System at Rocky Flats Environmental Technology Site (RFETS). The contaminants of concern (COCS) are uranium, TCE, PCE, carbon tetrachloride, americium, and vinyl chloride. The three reactive media evaluated included high carbon steel iron filings, an iron-silica alloy in the form of a foam aggregate, and a peculiar humic acid based sorbent (Humasorb from Arctech) mixed with sand. Each material was tested in the laboratory at column scale using simulated site water. All three materials showed promise for the 903 Mound Site however, the iron filings were determined to be the least expensive media. In order to validate the laboratory results, the iron filings were further tested at a pilot scale (field columns) using actual site water. Pilot test results were similar to laboratory results; consequently, the iron filings were chosen for the fill-scale demonstration of the reactive barrier technology. Additional design parameters including saturated hydraulic conductivity, treatment residence time, and head loss across the media were also determined and provided to the design team in support of the final design. The final design was completed by the Corps of Engineers in 1997 and the system was constructed in the summer of 1998. The treatment system began fill operation in December, 1998 and despite a few problems has been operational since. Results to date are consistent with the lab and pilot scale findings, i.e., complete removal of the contaminants of concern (COCs) prior to discharge to meet RFETS cleanup requirements. Furthermore, it is fair to say at this point in time that laboratory developed design parameters for the reactive barrier technology are sufficient for fuel scale design; however,the treatment system longevity and the long-term fate of the contaminants are questions that remain unanswered. This

Membrane barriers for radon gas flow restrictions

International Nuclear Information System (INIS)

Archibald, J.F.

1984-08-01

Research was performed to assess the feasibility of barrier membrane substances, for use within mining or associated high risk environments, in restricting the diffusion transport of radon gas quantities. Specific tests were conducted to determine permeability parameters of a variety of membrane materials with reference to radon flow capabilities. Tests were conducted both within laboratory and in-situ emanation environments where concentrations and diffusion flows of radon gas were known to exist. Equilibrium radon gas concentrations were monitored in initially radon-free chambers adjacent to gas sources, but separated by specified membrane substances. Membrane barrier effectiveness was demonstrated to result in reduced emanation concentrations of radon gas within the sampling chamber atmosphere. Minimum gas concentrations were evidenced where the barrier membrane material was shown to exhibit lowest radon permeability characteristics

PIWIL1/piRNA-DQ593109 Regulates the Permeability of the Blood-Tumor Barrier via the MEG3/miR-330-5p/RUNX3 Axis

Directory of Open Access Journals (Sweden)

Shuyuan Shen

2018-03-01

Full Text Available The blood-tumor barrier (BTB restricts the efficient delivery of anti-glioma drugs to cranial glioma tissues. Increased BTB permeability may allow greater delivery of the therapeutic agents. Increasing evidence has revealed that PIWI proteins and PIWI-interacting RNAs (piRNAs play an important role in tumor progression. However, whether PIWI proteins and piRNAs regulate BTB permeability remains unclear. In the present study, we demonstrated that the PIWIL1/piRNA-DQ593109 (piR-DQ593109 complex was the predominant regulator of BTB permeability. Briefly, PIWIL1 was upregulated in glioma endothelial cells (GECs. Furthermore, piR-DQ593109 was also overexpressed in GECs, as revealed via a piRNA microarray. Downregulation of PIWIL1 or piR-DQ593109 increased the permeability of the BTB. Moreover, PIWIL1 and piR-DQ593109, which formed a piRNA-induced silencing complex, degraded the long non-coding RNA maternally expressed 3 (MEG3 in a sequenced-dependent manner. Furthermore, restoring MEG3 released post-transcriptional inhibition of Runt related transcription factor 3 (RUNX3 by sponging miR-330-5p. In addition, RUNX3 bounded to the promoter regions and reduced the promoter activities of ZO-1, occludin, and claudin-5, which significantly impaired the expression levels of ZO-1, occludin, and claudin-5. In conclusion, downregulating PIWIL1 and piR-DQ593109 increased BTB permeability through the MEG3/miR-330-5p/RUNX3 axis. These data may provide insight into glioma treatment.

Paracytosis of Haemophilus influenzae through cell layers of NCI-H292 lung epithelial cells

NARCIS (Netherlands)

van Schilfgaarde, M.; van Alphen, L.; Eijk, P.; Everts, V.; Dankert, J.

1995-01-01

Haemophilus influenzae penetrates the respiratory epithelium during carriage and invasive disease, including respiratory tract infections. We developed an in vitro model system consisting of lung epithelial NCI-H292 cells on permeable supports to study the passage of H. influenzae through lung

Application of kinetic models to the design of a calcite permeable reactive barrier (PRB) for fluoride remediation.

Science.gov (United States)

Cai, Qianqian; Turner, Brett D; Sheng, Daichao; Sloan, Scott

2018-03-01

The kinetics of fluoride sorption by calcite in the presence of metal ions (Co, Mn, Cd and Ba) have been investigated and modelled using the intra-particle diffusion (IPD), pseudo-second order (PSO), and the Hill 4 and Hill 5 kinetic models. Model comparison using the Akaike Information Criterion (AIC), the Schwarz Bayseian Information Criterion (BIC) and the Bayes Factor allows direct comparison of model results irrespective of the number of model parameters. Information Criterion results indicate "very strong" evidence that the Hill 5 model was the best fitting model for all observed data due to its ability to fit sigmoidal data, with confidence contour analysis showing the model parameters were well constrained by the data. Kinetic results were used to determine the thickness of a calcite permeable reactive barrier required to achieve up to 99.9% fluoride removal at a groundwater flow of 0.1 m.day -1 . Fluoride removal half-life (t 0.5 ) values were found to increase in the order Ba ≈ stonedust (a 99% pure natural calcite) barrier width of 0.97 ± 0.02 m was found to be required for the fluoride/calcite (stonedust) only system when using no factor of safety, whilst in the presence of Mn and Co, the width increased to 2.76 ± 0.28 and 19.83 ± 0.37 m respectively. In comparison, the PSO model predicted a required barrier thickness of ∼46.0, 62.6 & 50.3 m respectively for the fluoride/calcite, Mn and Co systems under the same conditions. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Uranium Removal from Groundwater by Permeable Reactive Barrier with Zero-Valent Iron and Organic Carbon Mixtures: Laboratory and Field Studies

Directory of Open Access Journals (Sweden)

Borys Kornilovych

2018-06-01

Full Text Available Zhovty Vody city, located in south-central Ukraine, has long been an important center for the Ukrainian uranium and iron industries. Uranium and iron mining and processing activities during the Cold War resulted in poorly managed sources of radionuclides and heavy metals. Widespread groundwater and surface water contamination has occurred, which creates a significant risk to drinking water supplies. Hydrogeologic and geochemical conditions near large uranium mine tailings storage facility (TSF were characterized to provide data to locate, design and install a permeable reactive barrier (PRB to treat groundwater contaminated by leachate infiltrating from the TSF. The effectiveness of three different permeable reactive materials was investigated: zero-valent iron (ZVI for reduction, sorption, and precipitation of redox-sensitive oxyanions; phosphate material to transform dissolved metals to less soluble phases; and organic carbon substrates to promote bioremediation processes. Batch and column experiments with Zhovty Vody site groundwater were conducted to evaluate reactivity of the materials. Reaction rates, residence time and comparison with site-specific clean-up standards were determined. Results of the study demonstrate the effectiveness of the use of the PRB for ground water protection near uranium mine TSF. The greatest decrease was obtained using ZVI-based reactive media and the combined media of ZVI/phosphate/organic carbon combinations.

A polymeric micelle magnetic resonance imaging (MRI) contrast agent reveals blood-brain barrier (BBB) permeability for macromolecules in cerebral ischemia-reperfusion injury.

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Shiraishi, Kouichi; Wang, Zuojun; Kokuryo, Daisuke; Aoki, Ichio; Yokoyama, Masayuki

2017-05-10

Blood-brain barrier (BBB) opening is a key phenomenon for understanding ischemia-reperfusion injuries that are directly linked to hemorrhagic transformation. The recombinant human tissue-type plasminogen activator (rtPA) increases the risk of symptomatic intracranial hemorrhages. Recent imaging technologies have advanced our understanding of pathological BBB disorders; however, an ongoing challenge in the pre-"rtPA treatment" stage is the task of developing a rigorous method for hemorrhage-risk assessments. Therefore, we examined a novel method for assessment of rtPA-extravasation through a hyper-permeable BBB. To examine the image diagnosis of rtPA-extravasation for a rat transient occlusion-reperfusion model, in this study we used a polymeric micelle MRI contrast-agent (Gd-micelles). Specifically, we used two MRI contrast agents at 1h after reperfusion. Gd-micelles provided very clear contrast images in 15.5±10.3% of the ischemic hemisphere at 30min after i.v. injection, whereas a classic gadolinium chelate MRI contrast agent provided no satisfactorily clear images. The obtained images indicate both the hyper-permeable BBB area for macromolecules and the distribution area of macromolecules in the ischemic hemisphere. Owing to their large molecular weight, Gd-micelles remained in the ischemic hemisphere through the hyper-permeable BBB. Our results indicate the feasibility of a novel clinical diagnosis for evaluating rtPA-related hemorrhage risks. Copyright © 2017 Elsevier B.V. All rights reserved.

A high-grain diet alters the omasal epithelial structure and expression of tight junction proteins in a goat model.

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Liu, Jun-Hua; Xu, Ting-Ting; Zhu, Wei-Yun; Mao, Sheng-Yong

2014-07-01

The omasal epithelial barrier plays important roles in maintaining nutrient absorption and immune homeostasis in ruminants. However, little information is currently available about the changes in omasal epithelial barrier function at the structural and molecular levels during feeding of a high-grain (HG) diet. Ten male goats were randomly assigned to two groups, fed either a hay diet (0% grain; n = 5) or HG diet (65% grain; n = 5). Changes in omasal epithelial structure and expression of tight junction (TJ) proteins were determined via electron microscopy and Western blot analysis. After 7 weeks on each diet, omasal contents in the HG group showed significantly lower pH (P diet showed profound alterations in omasal epithelial structure and TJ proteins, corresponding to depression of thickness of total epithelia, stratum granulosum, and the sum of the stratum spinosum and stratum basale, marked epithelial cellular damage, erosion of intercellular junctions and down-regulation in expression of the TJ proteins, claudin-4 and occludin. The study demonstrates that feeding a HG diet is associated with omasal epithelial cellular damage and changes in expression of TJ proteins. These research findings provide an insight into the possible significance of diet on the omasal epithelial barrier in ruminants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cholinergic modulation of epithelial integrity in the proximal colon of pigs.

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Lesko, Szilvia; Wessler, Ignaz; Gäbel, Gotthold; Petto, Carola; Pfannkuche, Helga

2013-01-01

Within the gut, acetylcholine (ACh) is synthesised by enteric neurons, as well as by 'non-neuronal' epithelial cells. In studies of non-intestinal epithelia, ACh was involved in the generation of an intact epithelial barrier. In the present study, primary cultured porcine colonocytes were used to determine whether treatment with exogenous ACh or expression of endogenous epithelium-derived ACh may modulate epithelial tightness in the gastrointestinal tract. Piglet colonocytes were cultured on filter membranes for 8 days. The tightness of the growing epithelial cell layer was evaluated by measuring transepithelial electrical resistance (TEER). To determine whether ACh modulates the tightness of the cell layer, cells were treated with cholinergic, muscarinic and/or nicotinic agonists and antagonists. Choline acetyltransferase (ChAT), cholinergic receptors and ACh were determined by immunohistochemistry, RT-PCR and HPLC, respectively. Application of the cholinergic agonist carbachol (10 µm) and the muscarinic agonist oxotremorine (10 µM) resulted in significantly higher TEER values compared to controls. The effect was completely inhibited by the muscarinic antagonist atropine. Application of atropine alone (without any agonist) led to significantly lower TEER values compared to controls. Synthesis of ACh by epithelial cells was proven by detection of muscarinic and nicotinic receptor mRNAs, immunohistochemical detection of ChAT and detection of ACh by HPLC. ACh is strongly involved in the regulation of epithelial tightness in the proximal colon of pigs via muscarinic pathways. Non-neuronal ACh seems to be of particular importance for epithelial cells forming a tight barrier. Copyright © 2013 S. Karger AG, Basel.

Phosphatidylcholine Reverses Ethanol-Induced Increase in Transepithelial Endotoxin Permeability and Abolishes Transepithelial Leukocyte Activation

DEFF Research Database (Denmark)

Mitzscherling, Katja; Volynets, Valentina; Parlesak, Alexandr

2009-01-01

Chronic alcohol abuse increases both intestinal bacterial overgrowth and intestinal permeability to macromolecules. Intestinal permeability of endotoxin, a component of the outer cell membrane of Gram-negative bacteria, plays a crucial role in the development of alcohol-induced liver disease (ALD......). As impaired bile flow leads to endotoxemia and the bile component phosphatidylcholine (PC) is therapeutically active in ALD, we tested the hypothesis that conjugated primary bile salts (CPBS) and PC inhibit ethanol-enhanced transepithelial permeability of endotoxin and the subsequent transepithelial...... activation of human leukocytes. For this purpose, we used a model in which intestinal epithelial cells (Caco-2) were basolaterally cocultivated with mononuclear leukocytes. Cells were challenged apically with endotoxin from Escherichia coli K12 and were incubated with or without the addition of CPBS (1.5 m...

Diamond and Diamond-Like Materials as Hydrogen Isotope Barriers

International Nuclear Information System (INIS)

Foreman, L.R.; Barbero, R.S.; Carroll, D.W.; Archuleta, T.; Baker, J.; Devlin, D.; Duke, J.; Loemier, D.; Trukla, M.

1999-01-01

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project was to develop diamond and diamond-like thin-films as hydrogen isotope permeation barriers. Hydrogen embrittlement limits the life of boost systems which otherwise might be increased to 25 years with a successful non-reactive barrier. Applications in tritium processing such as bottle filling processes, tritium recovery processes, and target filling processes could benefit from an effective barrier. Diamond-like films used for low permeability shells for ICF and HEDP targets were also investigated. Unacceptable high permeabilities for hydrogen were obtained for plasma-CVD diamond-like-carbon films

Evaluation of five strategies to limit the impact of fouling in permeable reactive barriers

International Nuclear Information System (INIS)

Li Lin; Benson, Craig H.

2010-01-01

Ground water flow and geochemical reactive transport models were used to assess the effectiveness of five strategies used to limit fouling and to enhance the long-term hydraulic behavior of continuous-wall permeable reactive barriers (PRBs) employing granular zero valent iron (ZVI). The flow model accounted for geological heterogeneity and the reactive transport model included a geochemical algorithm for simulating iron corrosion and mineral precipitation reactions that have been observed in ZVI PRBs. The five strategies that were evaluated are pea gravel equalization zones, a sacrificial pre-treatment zone, pH adjustment, large ZVI particles, and mechanical treatment. Results of simulations show that installation of pea gravel equalization zones results in flow equalization and a more uniform distribution of residence times within the PRB. Residence times within the PRB are less affected by mineral precipitation when a pre-treatment zone is employed. pH adjustment limits the total amount of hydroxide ions in ground water to reduce porosity reduction and to retain larger residence times. Larger ZVI particles reduce porosity reduction as a result of the smaller iron surface area for iron corrosion, and retain longer residence time. Mechanical treatment redistributes the porosity uniformly throughout the PRB over time, which is effective in maintaining residence time.

Blood-brain barrier permeability and neuroprotective effects of three main alkaloids from the fruits of Euodia rutaecarpa with MDCK-pHaMDR cell monolayer and PC12 cell line.

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Zhang, Yi-Nan; Yang, Yan-Fang; Yang, Xiu-Wei

2018-02-01

The fruits of Euodia rutaecarpa (Euodiae Fructus, EF), the widely used traditional Chinese medicine, have various central nervous system effects. Alkaloids following as evodiamine (EDM), rutaecarpine (RCP) and dehydroevodiamine (DEDM) are the major substances in EF. The MDCK-pHaMDR cell monolayer model was utilized as a blood-brain barrier (BBB) surrogate model to study their BBB permeability. The transport samples were analyzed by high performance liquid chromatography and the apparent permeability coefficients (P app ) were calculated. EDM and RCP showed high permeability through BBB by passive diffusion, while DEDM showed moderate permeability with efflux mechanism related to P-glycoprotein (P-gp). EDM and RCP could also reduce the efflux of DEDM probably by inhibiting P-gp. The neuroprotective effects of the three alkaloids were then studied on the PC12 cell line injured by 1-methyl-4-phenylpyridinium ion (MPP + ) or hydrogen peroxide (H 2 O 2 ). EDM could significantly reduce MPP + or H 2 O 2 -induced cell injury dose-dependently. RCP could increase the cell viability in MPP + treated group while DEDM showed a protective effect against H 2 O 2 injury. This study predicted the permeability of EDM, RCP and DEDM through BBB and discovered the neuroprotective substance basis of EF as a potential encephalopathy drug. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Bronchoalveolar permeability changes in rats inhaling gas/particle combinations during rest or exercise

International Nuclear Information System (INIS)

Bhalla, D.K.; Phalen, R.F.; Mannix, R.C.; Lavan, S.M.; Crocker, T.T.

1986-01-01

Bronchoalveolar (BA) injury in rats exposed at rest or exercise to air pollutants was studied by changes in epithelial permeability. Rats exposed to air, single gases or pollutant combinations were anesthetized, tracheostomized, and placed on an incline. /sup 99m/Tc-DTPA was delivered directly to a major bronchus. Radioactivity measurements were made on blood samples collected during first 10 min. Exposure of resting rats to 0.6 ppm O 3 increased BA permeability just after exposure, but it was normal 24 hrs later; in exercising rats the increase was greater than in rats exposed at rest, and it persisted up to 24 hrs. NO 2 at 6 ppm did not affect permeability. Exposure of resting rats to 2.5 ppm NO 2 + 0.6 ppm O 3 only increased permeability right after the exposure, but in exercising rats this exposure resulted in a greater permeability which remained elevated up to 24 hrs. Exposure of exercising rats to 0.8 ppm O 3 + 10 ppm HCHO increased permeability. Exposure of resting rats to an atmosphere of 0.6 ppm O 3 + 2.5 ppm NO 2 + 5 ppm SO 2 + 1 mg/m 3 sulfates of ferric, ammonium and manganese also produced an increase in permeability that persisted up to 24 hrs. The results suggest potentiation of the pollutant effects by exercise, but there is no indication of synergistic effect of pollutant combinations on BA permeability

Alveolar epithelial fluid transport capacity in reperfusion lung injury after lung transplantation.

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Ware, L B; Golden, J A; Finkbeiner, W E; Matthay, M A

1999-03-01

Reperfusion lung injury is an important cause of morbidity and mortality after orthotopic lung transplantation. The purpose of this study was to investigate the function of the alveolar epithelium in the setting of reperfusion lung injury. Simultaneous samples of pulmonary edema fluid and plasma were collected from eight patients with severe post-transplantation reperfusion edema. The edema fluid to plasma protein ratio was measured, an indicator of alveolar-capillary barrier permeability. The initial edema fluid to plasma protein ratio was > 0.75 in six of eight patients, confirming the presence of increased permeability of the alveolar-capillary barrier. Graft ischemic time was positively correlated with the degree of permeability (r = 0.77, p mean +/- SD). Alveolar fluid clearance was calculated from serial samples in six patients. Intact alveolar fluid clearance correlated with less histologic injury, rapid resolution of hypoxemia, and more rapid resolution of radiographic infiltrates. The two patients with no net alveolar fluid clearance had persistent hypoxemia and more severe histologic injury. This study provides the first direct evidence that increased permeability to protein is the usual cause of reperfusion edema after lung transplantation, with longer ischemic times associated with greater permeability to protein in the transplanted lung. The high rates of alveolar fluid clearance indicate that the fluid transport capacity of the alveolar epithelium may be well preserved in the allograft despite reperfusion lung injury. The ability to reabsorb fluid from the alveolar space was a marker of less severe reperfusion injury, whereas the degree of alveolar-capillary barrier permeability to protein was not. Measurement of alveolar fluid clearance may be useful to assess the severity of reperfusion lung injury and to predict outcome when pulmonary edema develops after lung transplantation.

Saccharomyces boulardii CNCM I-745 Restores intestinal Barrier Integrity by Regulation of E-cadherin Recycling.

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Terciolo, Chloé; Dobric, Aurélie; Ouaissi, Mehdi; Siret, Carole; Breuzard, Gilles; Silvy, Françoise; Marchiori, Bastien; Germain, Sébastien; Bonier, Renaté; Hama, Adel; Owens, Roisin; Lombardo, Dominique; Rigot, Véronique; André, Frédéric

2017-08-01

Alteration in intestinal permeability is the main factor underlying the pathogenesis of many diseases affecting the gut, such as inflammatory bowel disease [IBD]. Characterization of molecules targeting the restoration of intestinal barrier integrity is therefore vital for the development of alternative therapies. The yeast Saccharomyces boulardii CNCM I-745 [Sb], used to prevent and treat antibiotic-associated infectious and functional diarrhea, may have a beneficial effect in the treatment of IBD. We analyzed the impact of Sb supernatant on tissue integrity and components of adherens junctions using cultured explants of colon from both IBD and healthy patients. To evaluate the pathways by which Sb regulates the expression of E-cadherin at the cell surface, we developed in vitro assays using human colonic cell lines, including cell aggregation, a calcium switch assay, real-time measurement of transepithelial electrical resistance [TEER] and pulse-chase experiments. We showed that Sb supernatant treatment of colonic explants protects the epithelial morphology and maintains E-cadherin expression at the cell surface. In vitro experiments revealed that Sb supernatant enhances E-cadherin delivery to the cell surface by re-routing endocytosed E-cadherin back to the plasma membrane. This process, involving Rab11A-dependent recycling endosome, leads to restoration of enterocyte adherens junctions, in addition to the overall restoration and strengthening of intestinal barrier function. These findings open new possibilities of discovering novel options for prevention and therapy of diseases that affect intestinal permeability. Copyright © 2017 European Crohn's and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com

Oxcarbazepine-loaded polymeric nanoparticles: development and permeability studies across in vitro models of the blood–brain barrier and human placental trophoblast

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Lopalco A

2015-03-01

Full Text Available Antonio Lopalco,1–3,* Hazem Ali,1,* Nunzio Denora,3 Erik Rytting1,4,5 1Department of Obstretrics and Gynecology, University of Texas Medical Branch, Galveston, TX, USA; 2Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA; 3Department of Pharmacy – Drug Sciences, University of Bari Aldo Moro, Bari, Italy; 4Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, TX, USA; 5Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA *These authors contributed equally to this work Abstract: Encapsulation of antiepileptic drugs (AEDs into nanoparticles may offer promise for treating pregnant women with epilepsy by improving brain delivery and limiting the transplacental permeability of AEDs to avoid fetal exposure and its consequent undesirable adverse effects. Oxcarbazepine-loaded nanoparticles were prepared by a modified solvent displacement method from biocompatible polymers (poly(lactic-co-glycolic acid [PLGA] with or without surfactant and PEGylated PLGA [Resomer® RGPd5055]. The physical properties of the developed nanoparticles were determined with subsequent evaluation of their permeability across in vitro models of the blood–brain barrier (hCMEC/D3 cells and human placental trophoblast cells (BeWo b30 cells. Oxcarbazepine-loaded nanoparticles with encapsulation efficiency above 69% were prepared with sizes ranging from 140–170 nm, polydispersity indices below 0.3, and zeta potential values below −34 mV. Differential scanning calorimetry and X-ray diffraction studies confirmed the amorphous state of the nanoencapsulated drug. The apparent permeability (Pe values of the free and nanoencapsulated oxcarbazepine were comparable across both cell types, likely due to rapid drug release kinetics. Transport studies using fluorescently-labeled nanoparticles (loaded with coumarin-6 demonstrated increased permeability of surfactant-coated nanoparticles

Influence of hilar deposition in the evaluation of the alveolar epithelial permeability on 99mTc-DTPA aerosol inhaled scintigraphy

International Nuclear Information System (INIS)

Ogi, Shigeyuki; Uchiyama, Mayuki; Fukuda, Kunihiko; Urashima, Mitsuyoshi; Gotoh, Eisuke; Fukumitsu, Nobuyoshi

2009-01-01

We investigated whether hilar radioaerosol deposition affects the clearance rate of technetium-99m-labeled diethylenetriaminepentaacetic acid ( 99m Tc-DTPA) from peripheral alveolar regions. A total of 38 patients underwent 99m Tc-DTPA inhalation lung scintigraphy. Six region of interest (ROI) patterns were adopted: ROI 1 was outlined around the entire hemithorax, and ROIs 2-6 were outlined around the hemithorax but excluded square ROIs of different size in the hilar region. Half-times (T 1/2 ) were calculated with time-activity curves using one-compartment and two-compartment analyses. The T 1/2 of ROIs 1-5 were plotted against the T 1/2 of ROI 6, and regression lines were obtained with the least-squares method. The absolute values of the differences between surveyed values and regression line were calculated. The Wilcoxon test for trend and a single linear regression model were used to determine statistical significance. There were significant reductions in the absolute values of the differences between surveyed values and regression line from ROIs 1-5 by one-component analysis and the fast component of two-compartment analysis (P 99m Tc-DTPA from the alveoli in damaged lungs. The hilar region should be excluded from ROIs when alveolar epithelial permeability is evaluated. (author)

In vitro effect of carprofen and meloxicam on the conductance and permeability to mannitol and the histologic appearance of the gastric mucosa of dogs.

Science.gov (United States)

Hicks, Merrin A; Hosgood, Giselle L; Morgan, Timothy W; Briere, Catherine A; McConnico, Rebecca S

2011-04-01

To evaluate the effects of carprofen and meloxicam on conductance and permeability to mannitol and on the histologic appearance of sections of canine gastric mucosa. Gastric mucosa from 6 mature mixed-breed dogs. Sections of gastric mucosa were mounted in Ussing chambers, and carprofen (40 or 400μg/mL [CAR40 and CAR400, respectively]), meloxicam (8 or 80μg/mL [MEL8 and MEL80, respectively]), or no drug (controls) was added to the bathing solution. For all sections, conductance was calculated every 15 minutes for 240 minutes and flux of mannitol was calculated for 3 consecutive 1-hour periods; histologic examination was performed after the experiment. The area under the conductance-time curve for each chamber was calculated. Values of conductance × time, flux of mannitol, and the frequency distribution of histologic findings were analyzed for treatment effects. For CAR400- and MEL80-treated sections, conductance X time was significantly higher than that for control and MEL8-treated sections. The effect of CAR40 treatment was not different from that of any other treatment. Over the three 1-hour periods, mannitol flux increased significantly in MEL80-, CAR40-, and CAR400-treated sections but not in MEL8- treated or control sections. Major histologic changes including epithelial cell sloughing were limited to the CAR400-treated sections. In the gastric mucosa of dogs, carprofen and meloxicam increased in vitro conductance and permeability to mannitol. At a concentration of 400 μg/mL, carprofen caused sloughing of epithelial cells. Carprofen and meloxicam appear to compromise gastric mucosal integrity and barrier function in dogs.

Bacterial Signaling at the Intestinal Epithelial Interface in Inflammation and Cancer

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Olivia I. Coleman

2018-01-01

Full Text Available The gastrointestinal (GI tract provides a compartmentalized interface with an enormous repertoire of immune and metabolic activities, where the multicellular structure of the mucosa has acquired mechanisms to sense luminal factors, such as nutrients, microbes, and a variety of host-derived and microbial metabolites. The GI tract is colonized by a complex ecosystem of microorganisms, which have developed a highly coevolved relationship with the host’s cellular and immune system. Intestinal epithelial pattern recognition receptors (PRRs substantially contribute to tissue homeostasis and immune surveillance. The role of bacteria-derived signals in intestinal epithelial homeostasis and repair has been addressed in mouse models deficient in PRRs and signaling adaptors. While critical for host physiology and the fortification of barrier function, the intestinal microbiota poses a considerable health challenge. Accumulating evidence indicates that dysbiosis is associated with the pathogenesis of numerous GI tract diseases, including inflammatory bowel diseases (IBD and colorectal cancer (CRC. Aberrant signal integration at the epithelial cell level contributes to such diseases. An increased understanding of bacterial-specific structure recognition and signaling mechanisms at the intestinal epithelial interface is of great importance in the translation to future treatment strategies. In this review, we summarize the growing understanding of the regulation and function of the intestinal epithelial barrier, and discuss microbial signaling in the dynamic host–microbe mutualism in both health and disease.

Methamphetamine transiently increases the blood-brain barrier permeability in the hippocampus: role of tight junction proteins and matrix metalloproteinase-9.

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Martins, Tânia; Baptista, Sofia; Gonçalves, Joana; Leal, Ermelindo; Milhazes, Nuno; Borges, Fernanda; Ribeiro, Carlos F; Quintela, Oscar; Lendoiro, Elena; López-Rivadulla, Manuel; Ambrósio, António F; Silva, Ana P

2011-09-09

Methamphetamine (METH) is a powerful stimulant drug of abuse that has steadily gained popularity worldwide. It is known that METH is highly neurotoxic and causes irreversible damage of brain cells leading to neurological and psychiatric abnormalities. Recent studies suggested that METH-induced neurotoxicity might also result from its ability to compromise blood-brain barrier (BBB) function. Due to the crucial role of BBB in the maintenance of brain homeostasis and protection against toxic molecules and pathogenic organisms, its dysfunction could have severe consequences. In this study, we investigated the effect of an acute high dose of METH (30mg/kg) on BBB permeability after different time points and in different brain regions. For that, young adult mice were sacrificed 1h, 24h or 72h post-METH administration. METH increased BBB permeability, but this effect was detected only at 24h after administration, being therefore a transitory effect. Interestingly, we also found that the hippocampus was the most susceptible brain region to METH, comparing to frontal cortex and striatum. Moreover, in an attempt to identify the key players in METH-induced BBB dysfunction we further investigated potential alterations in tight junction (TJ) proteins and matrix metalloproteinase-9 (MMP-9). METH was able to decrease the protein levels of zonula occludens (ZO)-1, claudin-5 and occludin in the hippocampus 24h post-injection, and increased the activity and immunoreactivity of MMP-9. The pre-treatment with BB-94 (30mg/kg), a matrix metalloproteinase inhibitor, prevented the METH-induced increase in MMP-9 immunoreactivity in the hippocampus. Overall, the present data demonstrate that METH transiently increases the BBB permeability in the hippocampus, which can be explained by alterations on TJ proteins and MMP-9. Copyright © 2011 Elsevier B.V. All rights reserved.

LOCALIZATION OF PERMEABILITY BARRIERS IN THE FROG SKIN EPITHELIUM

Science.gov (United States)

Martinez-Palomo, A.; Erlij, D.; Bracho, H.

1971-01-01

Ruthenium red and colloidal lanthanum were used to determine the site of the structural barriers to diffusion within the intercellular spaces of frog skin epithelium. Electron micrographs show that occluding zonules located at the outer border of the stratum corneum and at the outer layer of the stratum granulosum are true tight junctions since they are impermeable to these tracers. Measurement of 140La uptake by the living skin shows that lanthanum moves across the external surface of the skin readily, into and out of a compartment that has a limited capacity and is bounded on its internal side by a barrier impermeable to lanthanum. Examination of these skins with the electron microscope suggests that the compartment is localized between the external membrane of the cells at the outer layer of the s. granulosum and at the outermost surface of the skin. These observations and other findings described in the literature indicate that the site of the external high resistance barrier of the frog skin is localized at the outer border of the s. granulosum. PMID:4329611

AMP-18 Targets p21 to Maintain Epithelial Homeostasis.

Science.gov (United States)

Chen, Peili; Li, Yan Chun; Toback, F Gary

2015-01-01

Dysregulated homeostasis of epithelial cells resulting in disruption of mucosal barrier function is an important pathogenic mechanism in inflammatory bowel diseases (IBD). We have characterized a novel gastric protein, Antrum Mucosal Protein (AMP)-18, that has pleiotropic properties; it is mitogenic, anti-apoptotic and can stimulate formation of tight junctions. A 21-mer synthetic peptide derived from AMP-18 exhibits the same biological functions as the full-length protein and is an effective therapeutic agent in mouse models of IBD. In this study we set out to characterize therapeutic mechanisms and identify molecular targets by which AMP-18 maintains and restores disrupted epithelial homeostasis in cultured intestinal epithelial cells and a mouse model of IBD. Tumor necrosis factor (TNF)-α, a pro-inflammatory cytokine known to mediate gastrointestinal (GI) mucosal injury in IBD, was used to induce intestinal epithelial cell injury, and study the effects of AMP-18 on apoptosis and the cell cycle. An apoptosis array used to search for targets of AMP-18 in cells exposed to TNF-α identified the cyclin-dependent kinase inhibitor p21 WAF1/CIP1. Treatment with AMP-18 blunted increases in p21 expression and apoptosis, while reversing disturbed cell cycle kinetics induced by TNF-α. AMP-18 appears to act through PI3K/AKT pathways to increase p21 phosphorylation, thereby reducing its nuclear accumulation to overcome the antiproliferative effects of TNF-α. In vitamin D receptor-deficient mice with TNBS-induced IBD, the observed increase in p21 expression in colonic epithelial cells was suppressed by treatment with AMP peptide. The results indicate that AMP-18 can maintain and/or restore the homeostatic balance between proliferation and apoptosis in intestinal epithelial cells to protect and repair mucosal barrier homeostasis and function, suggesting a therapeutic role in IBD.

AMP-18 Targets p21 to Maintain Epithelial Homeostasis.

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Peili Chen

Full Text Available Dysregulated homeostasis of epithelial cells resulting in disruption of mucosal barrier function is an important pathogenic mechanism in inflammatory bowel diseases (IBD. We have characterized a novel gastric protein, Antrum Mucosal Protein (AMP-18, that has pleiotropic properties; it is mitogenic, anti-apoptotic and can stimulate formation of tight junctions. A 21-mer synthetic peptide derived from AMP-18 exhibits the same biological functions as the full-length protein and is an effective therapeutic agent in mouse models of IBD. In this study we set out to characterize therapeutic mechanisms and identify molecular targets by which AMP-18 maintains and restores disrupted epithelial homeostasis in cultured intestinal epithelial cells and a mouse model of IBD. Tumor necrosis factor (TNF-α, a pro-inflammatory cytokine known to mediate gastrointestinal (GI mucosal injury in IBD, was used to induce intestinal epithelial cell injury, and study the effects of AMP-18 on apoptosis and the cell cycle. An apoptosis array used to search for targets of AMP-18 in cells exposed to TNF-α identified the cyclin-dependent kinase inhibitor p21 WAF1/CIP1. Treatment with AMP-18 blunted increases in p21 expression and apoptosis, while reversing disturbed cell cycle kinetics induced by TNF-α. AMP-18 appears to act through PI3K/AKT pathways to increase p21 phosphorylation, thereby reducing its nuclear accumulation to overcome the antiproliferative effects of TNF-α. In vitamin D receptor-deficient mice with TNBS-induced IBD, the observed increase in p21 expression in colonic epithelial cells was suppressed by treatment with AMP peptide. The results indicate that AMP-18 can maintain and/or restore the homeostatic balance between proliferation and apoptosis in intestinal epithelial cells to protect and repair mucosal barrier homeostasis and function, suggesting a therapeutic role in IBD.

Corneal and conjunctival drug permeability: Systematic comparison and pharmacokinetic impact in the eye.

Science.gov (United States)

Ramsay, Eva; Del Amo, Eva M; Toropainen, Elisa; Tengvall-Unadike, Unni; Ranta, Veli-Pekka; Urtti, Arto; Ruponen, Marika

2018-07-01

On the surface of the eye, both the cornea and conjunctiva are restricting ocular absorption of topically applied drugs, but barrier contributions of these two membranes have not been systemically compared. Herein, we studied permeability of 32 small molecular drug compounds across an isolated porcine cornea and built a quantitative structure-property relationship (QSPR) model for the permeability. Corneal drug permeability (data obtained for 25 drug molecules) showed a 52-fold range in permeability (0.09-4.70 × 10 -6  cm/s) and the most important molecular descriptors in predicting the permeability were hydrogen bond donor, polar surface area and halogen ratio. Corneal permeability values were compared to their conjunctival drug permeability values. Ocular drug bioavailability and systemic absorption via conjunctiva were predicted for this drug set with pharmacokinetic calculations. Drug bioavailability in the aqueous humour was simulated to be drug across the conjunctiva to the blood circulation restricts significantly ocular drug bioavailability and, therefore, ocular absorption does not increase proportionally with the increasing corneal drug permeability. Copyright © 2018 Elsevier B.V. All rights reserved.

A microfluidic cell culture device with integrated microelectrodes for barrier studies

DEFF Research Database (Denmark)

Tan, Hsih-Yin; Dufva, Martin; Kutter, Jörg P.

We present an eight cell culture microfluidic device fabricated using thiol-ene ‘click’ chemistry with embedded microelectrodes for evaluating barrier properties of human intestinal epithelial cells. The capability of the microelectrodes for trans-epithelial electrical resistance (TEER) measureme......) measurements was demonstrated by using confluent human colorectal epithelial cells (Caco-2) and rat fibroblast (CT 26) cells cultured in the microfluidic device....

Mechanisms of pertussis toxin-induced barrier dysfunction in bovine pulmonary artery endothelial cell monolayers.

Science.gov (United States)

Patterson, C E; Stasek, J E; Schaphorst, K L; Davis, H W; Garcia, J G

1995-06-01

We have previously characterized several G proteins in endothelial cells (EC) as substrates for the ADP-ribosyltransferase activity of both pertussis (PT) and cholera toxin and described the modulation of key EC physiological responses, including gap formation and barrier function, by these toxins. In this study, we investigated the mechanisms involved in PT-mediated regulation of bovine pulmonary artery endothelial cells barrier function. PT caused a dose-dependent increase in albumin transfer, dependent upon action of the holotoxin, since neither the heat-inactivated PT, the isolated oligomer, nor the protomer induced EC permeability. PT-induced gap formation and barrier dysfunction were additive to either thrombin- or thrombin receptor-activating peptide-induced permeability, suggesting that thrombin and PT utilize distinct mechanisms. PT did not result in Ca2+ mobilization or alter either basal or thrombin-induced myosin light chain phosphorylation. However, PT stimulated protein kinase C (PKC) activation, and both PKC downregulation and PKC inhibition attenuated PT-induced permeability, indicating that PKC activity is involved in PT-induced barrier dysfunction. Like thrombin-induced permeability, the PT effect was blocked by prior increases in adenosine 3',5'-cyclic monophosphate. Thus PT-catalyzed ADP-ribosylation of a G protein (possibly other than Gi) may regulate cytoskeletal protein interactions, leading to EC barrier dysfunction.

Lymphocytes accelerate epithelial tight junction assembly: role of AMP-activated protein kinase (AMPK.

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Xiao Xiao Tang

2010-08-01

Full Text Available The tight junctions (TJs, characteristically located at the apicolateral borders of adjacent epithelial cells, are required for the proper formation of epithelial cell polarity as well as for sustaining the mucosal barrier to the external environment. The observation that lymphocytes are recruited by epithelial cells to the sites of infection [1] suggests that they may play a role in the modulation of epithelial barrier function and thus contribute to host defense. To test the ability of lymphocytes to modulate tight junction assembly in epithelial cells, we set up a lymphocyte-epithelial cell co-culture system, in which Madin-Darby canine kidney (MDCK cells, a well-established model cell line for studying epithelial TJ assembly [2], were co-cultured with mouse lymphocytes to mimic an infection state. In a typical calcium switch experiment, the TJ assembly in co-culture was found to be accelerated compared to that in MDCK cells alone. This accelaration was found to be mediated by AMP-activated protein kinase (AMPK. AMPK activation was independent of changes in cellular ATP levels but it was found to be activated by the pro-inflammatory cytokine TNF-alpha. Forced suppression of AMPK, either with a chemical inhibitor or by knockdown, abrogated the accelerating effect of lymphocytes on TJ formation. Similar results were also observed in a co-culture with lymphocytes and Calu-3 human airway epithelial cells, suggesting that the activation of AMPK may be a general mechanism underlying lymphocyte-accelerated TJ assembly in different epithelia. These results suggest that signals from lymphocytes, such as cytokines, facilitate TJ assembly in epithelial cells via the activation of AMPK.

In silico modeling on ADME properties of natural products: Classification models for blood-brain barrier permeability, its application to traditional Chinese medicine and in vitro experimental validation.

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Zhang, Xiuqing; Liu, Ting; Fan, Xiaohui; Ai, Ni

2017-08-01

In silico modeling of blood-brain barrier (BBB) permeability plays an important role in early discovery of central nervous system (CNS) drugs due to its high-throughput and cost-effectiveness. Natural products (NP) have demonstrated considerable therapeutic efficacy against several CNS diseases. However, BBB permeation property of NP is scarcely evaluated both experimentally and computationally. It is well accepted that significant difference in chemical spaces exists between NP and synthetic drugs, which calls into doubt on suitability of available synthetic chemical based BBB permeability models for the evaluation of NP. Herein poor discriminative performance on BBB permeability of NP are first confirmed using internal constructed and previously published drug-derived computational models, which warrants the need for NP-oriented modeling. Then a quantitative structure-property relationship (QSPR) study on a NP dataset was carried out using four different machine learning methods including support vector machine, random forest, Naïve Bayes and probabilistic neural network with 67 selected features. The final consensus model was obtained with approximate 90% overall accuracy for the cross-validation study, which is further taken to predict passive BBB permeability of a large dataset consisting of over 10,000 compounds from traditional Chinese medicine (TCM). For 32 selected TCM molecules, their predicted BBB permeability were evaluated by in vitro parallel artificial membrane permeability assay and overall accuracy for in vitro experimental validation is around 81%. Interestingly, our in silico model successfully predicted different BBB permeation potentials of parent molecules and their known in vivo metabolites. Finally, we found that the lipophilicity, the number of hydrogen bonds and molecular polarity were important molecular determinants for BBB permeability of NP. Our results suggest that the consensus model proposed in current work is a reliable tool for

Intestinal permeability - a new target for disease prevention and therapy

NARCIS (Netherlands)

Bischoff, S.C.; Barbara, G.; Buurman, W.; Ockhuizen, T.; Schulzke, J.D.; Serino, M.; Tilg, H.; Watson, A.; Wells, J.M.

2014-01-01

Data are accumulating that emphasize the important role of the intestinal barrier and intestinal permeability for health and disease. However, these terms are poorly defined, their assessment is a matter of debate, and their clinical significance is not clearly established. In the present review,

The Deletion of Endothelial Sodium Channel α (αENaC Impairs Endothelium-Dependent Vasodilation and Endothelial Barrier Integrity in Endotoxemia in Vivo

Directory of Open Access Journals (Sweden)

Magdalena Sternak

2018-04-01

Full Text Available The role of epithelial sodium channel (ENaC activity in the regulation of endothelial function is not clear. Here, we analyze the role of ENaC in the regulation of endothelium-dependent vasodilation and endothelial permeability in vivo in mice with conditional αENaC subunit gene inactivation in the endothelium (endo-αENaCKO mice using unique MRI-based analysis of acetylcholine-, flow-mediated dilation and vascular permeability. Mice were challenged or not with lipopolysaccharide (LPS, from Salmonella typhosa, 10 mg/kg, i.p.. In addition, changes in vascular permeability in ex vivo organs were analyzed by Evans Blue assay, while changes in vascular permeability in perfused mesenteric artery were determined by a FITC-dextran-based assay. In basal conditions, Ach-induced response was completely lost, flow-induced vasodilation was inhibited approximately by half but endothelial permeability was not changed in endo-αENaCKO vs. control mice. In LPS-treated mice, both Ach- and flow-induced vasodilation was more severely impaired in endo-αENaCKO vs. control mice. There was also a dramatic increase in permeability in lungs, brain and isolated vessels as evidenced by in vivo and ex vivo analysis in endotoxemic endo-αENaCKO vs. control mice. The impaired endothelial function in endotoxemia in endo-αENaCKO was associated with a decrease of lectin and CD31 endothelial staining in the lung as compared with control mice. In conclusion, the activity of endothelial ENaC in vivo contributes to endothelial-dependent vasodilation in the physiological conditions and the preservation of endothelial barrier integrity in endotoxemia.

Organic substrates as electron donors in permeable reactive barriers for removal of heavy metals from acid mine drainage.

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Kijjanapanich, P; Pakdeerattanamint, K; Lens, P N L; Annachhatre, A P

2012-12-01

This research was conducted to select suitable natural organic substrates as potential carbon sources for use as electron donors for biological sulphate reduction in a permeable reactive barrier (PRB). A number of organic substrates were assessed through batch and continuous column experiments under anaerobic conditions with acid mine drainage (AMD) obtained from an abandoned lignite coal mine. To keep the heavy metal concentration at a constant level, the AMD was supplemented with heavy metals whenever necessary. Under anaerobic conditions, sulphate-reducing bacteria (SRB) converted sulphate into sulphide using the organic substrates as electron donors. The sulphide that was generated precipitated heavy metals as metal sulphides. Organic substrates, which yielded the highest sulphate reduction in batch tests, were selected for continuous column experiments which lasted over 200 days. A mixture of pig-farm wastewater treatment sludge, rice husk and coconut husk chips yielded the best heavy metal (Fe, Cu, Zn and Mn) removal efficiencies of over 90%.

Physiological barriers to the oral delivery of curcumin.

Science.gov (United States)

Berginc, K; Trontelj, J; Basnet, N Skalko; Kristl, A

2012-06-01

Curcumin, a principal component from Curcuma longa, with antioxidant and anti-inflammatory activities was proposed as a potential candidate for the preventation and/or treatment of cancer and chronic diseases. However, curcumin could not achieve its expected therapeutic outcome in clinical trials due to its low solubility and poor bioavailability. The actual intestinal physiological barriers limiting curcumin absorption after oral administration have not been fully investigated. To identify the main barriers curtailing its absorption, in vitro permeability of curcumin and flux of its glucuronide were monitored in rat jejunum and Transwell grown Caco-2 cells. Curcumin was more permeable under acidic conditions, but the permeability was substantially below the permeability of highly permeable standards. Its efflux could not be inhibited by specific Pgp and MRP inhibitors. BCRP was found to participate in curcumin transport, but the Organic Anion Transporting Polypeptide (OATP) did not. The permeability of curcumin significantly increased when the structure of mucus was compromised. The inhibitor of curcumin metabolism, piperin, failed to act as a permeability enhancer. Piperin inhibited Pgp and MRP transporters and decreased the amount of glucuronide transported back into the intestine. Inclusion of piperin in curcumin-containing formulations is highly recommended as to inhibit curcumin glucuronidation and to increase the transport of formed glucuronides into the plasma, therefore increasing the probability of glucuronide distribution into target tissue and inter-convertion to curcumin. It would also be beneficial, if curcumin delivery systems could reversibly compromise the mucous integrity to minimize the non-specific binding of curcumin to its constituents.

Effects of water activity and low molecular weight humectants on skin permeability and hydration dynamics - a double-blind, randomized and controlled study.

Science.gov (United States)

Albèr, C; Buraczewska-Norin, I; Kocherbitov, V; Saleem, S; Lodén, M; Engblom, J

2014-10-01

The mammalian skin is a barrier that effectively separates the water-rich interior of the body from the normally dryer exterior. Changes in the external conditions, for example ambient humidity, have been shown to affect the skin barrier properties. The prime objective of this study was to evaluate the effect of water activity of a topical formulation on skin hydration and permeability. A second objective was to gain more understanding on how two commonly used humectants, urea and glycerol, affect skin barrier function in vivo. Simple aqueous formulations were applied under occlusion to the volar forearm of healthy volunteers. Following 4-h exposure, skin water loss (by transepidermal water loss measurements), skin hydration (by Corneometry) and skin permeability (by time to vasodilation due to benzyl nicotinate exposure) were monitored. The results demonstrate that a relatively small change in the water activity of a topical formulation is sufficient to induce considerable effects on stratum corneum hydration and permeability to exogenous substances. Exposing the skin to high water activity leads to increased skin hydration and also increased permeability. Furthermore, urea and glycerol promote skin hydration and permeability even at reduced water activity of the applied formulation. These results highlight the importance of considering the water activity in topically applied formulations and the potential benefit of using humectants. The results may impact formulation optimization in how to facilitate skin hydration and to modify skin permeability by temporarily open and close the skin barrier. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Permeable reactive barriers for the remediation of groundwater in a mining area: results for a pilot-scale project

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Martinez-Sanchez, Maria Jose; Perez-Sirvent, Carmen; Garcia-Lorenzo, Maria Luz; Martinez-Lopez, Salvadora; Perez-Espinosa, Victor; Gonzalez-Ciudad, Eva; Belen Martinez-Martinez, Lucia; Hernandez, Carmen; Molina-Ruiz, Jose

2017-04-01

The Sierra Minera of Cartagena-La Union is located in the Region of Murcia, Southeast of Spain. This zone presents high levels of heavy metals due to natural, geogenic reasons. In addition, the prolonged mining activity, and subsequent abandonment of farms, has had consequences on the environment, including severe affectation of the groundwater in the area. To remediate this situation, the Permeable Reactive Barrier (PRB) technology was assayed, which required in addition to the hydro-geological study of the zone, a careful optimization study for the design and construction of PRBs. For such a purpose a pilot-scale project was developed, and this communication reports some of the most relevant findings obtained after a four-years monitorization period. The selected reactive material for the PRBs was limestone filler. The filler is a waste material produced in many factories in the zone. These residues have good adsorption properties, high alkalinity, low cost and high availability, which make them suitable for use in remediation. The PRB was constituted by a 50% limestone filler and 50% sand, a proportion optimized by means of independent batch experiments. A layer of gravel was placed at the top, and on it a layer of natural soil. The barrier was designed in the form of a continuous trench, because the level of the contaminated groundwater was not very deep. In this way, the barrier could be prepared with standard excavation equipment. Parallel to the barrier, 6 wells where arranged downstream for sample collection. The pH and conductivity of the samples was measured directly in situ, and the content of Zn, Cd, Cu, Fe, and Pb were analyzed in the laboratory. All the samples collected after the PRB was constructed had basic pH values between 7.5 and 8. The conductivity was between 5 and 11 mS / cm except for the well 4, which had a value of 3.70 mS / cm. The concentration values of trace elements were below the detection limit (atomic absorption measurement) in

Phototoxicity and cytotoxicity of fullerol in human retinal pigment epithelial cells

International Nuclear Information System (INIS)

Wielgus, Albert R.; Zhao, Baozhong; Chignell, Colin F.; Hu, Dan-Ning; Roberts, Joan E.

2010-01-01

The water-soluble nanoparticle hydroxylated fullerene [fullerol, nano-C 60 (OH) 22-26 ] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have previously found that fullerol is both cytotoxic and phototoxic to human lens epithelial cells (HLE B-3) and that the endogenous antioxidant lutein blocked some of this phototoxicity. In the present study we have found that fullerol induces cytotoxic and phototoxic damage to human retinal pigment epithelial cells. Accumulation of nano-C 60 (OH) 22-26 in the cells was confirmed spectrophotometrically at 405 nm, and cell viability, cell metabolism and membrane permeability were estimated using trypan blue, MTS and LDH assays, respectively. Fullerol was cytotoxic toward hRPE cells maintained in the dark at concentrations higher than 10 μM. Exposure to an 8.5 J.cm -2 dose of visible light in the presence of > 5 μM fullerol induced TBARS formation and early apoptosis, indicating phototoxic damage in the form of lipid peroxidation. Pretreatment with 10 and 20 μM lutein offered some protection against fullerol photodamage. Using time resolved photophysical techniques, we have now confirmed that fullerol produces singlet oxygen with a quantum yield of Φ = 0.05 in D 2 O and with a range of 0.002-0.139 in various solvents. As our previous studies have shown that fullerol also produces superoxide in the presence of light, retinal phototoxic damage may occur through both type I (free radical) and type II (singlet oxygen) mechanisms. In conclusion, ocular exposure to fullerol, particularly in the presence of sunlight, may lead to retinal damage.

De novo expression of sodium-glucose cotransporter SGLT2 in Bowman's capsule coincides with replacement of parietal epithelial cell layer with proximal tubule-like epithelium.

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Tabatabai, Niloofar M; North, Paula E; Regner, Kevin R; Kumar, Suresh N; Duris, Christine B; Blodgett, Amy B

2014-08-01

In kidney nephron, parietal epithelial cells line the Bowman's capsule and function as a permeability barrier for the glomerular filtrate. Bowman's capsule cells with proximal tubule epithelial morphology have been found. However, the effects of tubular metaplasia in Bowman's capsule on kidney function remain poorly understood. Sodium-glucose cotransporter 2 (SGLT2) plays a major role in reabsorption of glucose in the kidney and is expressed on brush border membrane (BBM) of epithelial cells in the early segment of the proximal tubule. We hypothesized that SGLT2 is expressed in tubularized Bowman's capsule and used our novel antibody to test this hypothesis. Immunohistochemical analysis was performed with our SGLT2 antibody on C57BL/6 mouse kidney prone to have tubularized Bowman's capsules. Cell membrane was examined with periodic acid-Schiff (PAS) stain. The results showed that SGLT2 was localized on BBM of the proximal tubules in young and adult mice. Bowman's capsules were lined mostly with normal brush border-less parietal epithelial cells in young mice, while they were almost completely covered with proximal tubule-like cells in adult mice. Regardless of age, SGLT2 was expressed on BBM of the tubularized Bowman's capsule but did not co-localize with nephrin in the glomerulus. SGLT2-expressing tubular cells expanded from the urinary pole toward the vascular pole of the Bowman's capsule. This study identified the localization of SGLT2 in the Bowman's capsule. Bowman's capsules with tubular metaplasia may acquire roles in reabsorption of filtered glucose and sodium.

Epithelial organization and cyst lumen expansion require efficient Sec13-Sec31-driven secretion.

Science.gov (United States)

Townley, Anna K; Schmidt, Katy; Hodgson, Lorna; Stephens, David J

2012-02-01

Epithelial morphogenesis is directed by interactions with the underlying extracellular matrix. Secretion of collagen and other matrix components requires efficient coat complex II (COPII) vesicle formation at the endoplasmic reticulum. Here, we show that suppression of the outer layer COPII component, Sec13, in zebrafish embryos results in a disorganized gut epithelium. In human intestinal epithelial cells (Caco-2), Sec13 depletion causes defective epithelial polarity and organization on permeable supports. Defects are seen in the ability of cells to adhere to the substrate, form a monolayer and form intercellular junctions. When embedded in a three-dimensional matrix, Sec13-depleted Caco-2 cells form cysts but, unlike controls, are defective in lumen expansion. Incorporation of primary fibroblasts within the three-dimensional culture substantially restores normal morphogenesis. We conclude that efficient COPII-dependent secretion, notably assembly of Sec13-Sec31, is required to drive epithelial morphogenesis in both two- and three-dimensional cultures in vitro, as well as in vivo. Our results provide insight into the role of COPII in epithelial morphogenesis and have implications for the interpretation of epithelial polarity and organization assays in cell culture.

The APC tumor suppressor is required for epithelial cell polarization and three-dimensional morphogenesis

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Lesko, Alyssa C.; Goss, Kathleen H.; Yang, Frank F.; Schwertner, Adam; Hulur, Imge; Onel, Kenan; Prosperi, Jenifer R.

2015-01-01

The Adenomatous Polyposis Coli (APC) tumor suppressor has been previously implicated in the control of apical-basal polarity; yet, the consequence of APC loss-of-function in epithelial polarization and morphogenesis has not been characterized. To test the hypothesis that APC is required for the establishment of normal epithelial polarity and morphogenesis programs, we generated APC-knockdown epithelial cell lines. APC depletion resulted in loss of polarity and multi-layering on permeable supports, and enlarged, filled spheroids with disrupted polarity in 3D culture. Importantly, these effects of APC knockdown were independent of Wnt/β-catenin signaling, but were rescued with either full-length or a carboxy (c)-terminal segment of APC. Moreover, we identified a gene expression signature associated with APC knockdown that points to several candidates known to regulate cell-cell and cell-matrix communication. Analysis of epithelial tissues from mice and humans carrying heterozygous APC mutations further support the importance of APC as a regulator of epithelial behavior and tissue architecture. These data also suggest that the initiation of epithelial-derived tumors as a result of APC mutation or gene silencing may be driven by loss of polarity and dysmorphogenesis. PMID:25578398

The influence of volatile anesthetics on alveolar epithelial permeability measured by noninvasive radionuclide lung scan

International Nuclear Information System (INIS)

Hung, Chih-Jen; Wu, Rick Sai-Chuen; Lin, Cheng-Chieh; Kao, Albert; Tsai, Jeffrey J.P.

2003-01-01

Many volatile anesthetics have long been thought to affect pulmonary functions including lung ventilation (LV) and alveolar epithelial permeability (AEP). The purpose of this study is to examine the influence of volatile anesthetics on LV and AEP by noninvasive radionuclide lung imaging of technetium-99m labeled diethylene triamine pentaacetic acid radioaerosol inhalation lung scan (DTPA lung scan). Twenty patients undergoing surgery and receiving volatile anesthesia with 1% halothane were enrolled as the study group 1. The other 20 patients undergoing surgery and receiving volatile anesthesia with 1.5% isoflurane were enrolled as the study group 2. At the same time, 20 patients undergoing surgery with intravenous anesthesia drugs were included as a control group. Before surgery, 1 hour after surgery, and 1 week after surgery, we investigated the 3 groups of patients with DTPA lung scan to evaluate LV and AEP by 99m Tc DTPA clearance halftime (T1/2). No significant change or abnormality of LV before surgery, 1 hour after surgery, or 1 week after surgery was found among the 3 groups of patients. In the control group, the 99m Tc DTPA clearance T1/2 was 63.5±16.4, 63.1±18.4, and 62.8±17.0 minutes, before surgery, 1 hour after surgery, and 1 week after surgery, respectively. In group 1, it was 65.9±9.3, 62.5±9.1, and 65.8±10.3 minutes, respectively. No significant change in AEP before surgery, 1 hour after surgery, or 1 week after surgery was found. However, in group 2, the 99m Tc DTPA clearance T1/2 was 65.5±13.2, 44.9±10.5, and 66.1±14.0 minutes, respectively. A significant transient change in AEP was found 1 hour after surgery, but it recovered 1 week after surgery. We conclude that volatile anesthesia is safe for LV and AEP, and only isoflurane can induce transient change of AEP. (author)

Epithelial-Mesenchymal Transition in Tissue Repair and Fibrosis

Science.gov (United States)

Stone, Rivka C.; Pastar, Irena; Ojeh, Nkemcho; Chen, Vivien; Liu, Sophia; Garzon, Karen I.; Tomic-Canic, Marjana

2016-01-01

Epithelial-mesenchymal transition (EMT) describes the global process by which stationary epithelial cells undergo phenotypic changes, including loss of cell-cell adhesion and apical-basal polarity, and acquire mesenchymal characteristics which confer migratory capacity. EMT and its converse, MET (mesenchymal-to-epithelial transition), are integral stages of many physiologic processes, and as such are tightly coordinated by a host of molecular regulators. Converging lines of evidence have identified EMT as a component of cutaneous wound healing, during which otherwise stationary keratinocytes - the resident skin epithelial cells - migrate across the wound bed to restore the epidermal barrier. Moreover, EMT also plays a role in the development of scarring and fibrosis, as the matrix-producing myofibroblast arises from cells of epithelial lineage in response to injury but is pathologically sustained instead of undergoing MET or apoptosis. In this review, we summarize the role of EMT in physiologic repair and pathologic fibrosis of tissues and organs. We conclude that further investigation into the contribution of EMT to the impaired repair of fibrotic wounds may identify components of EMT signaling as common therapeutic targets for impaired healing in many tissues. PMID:27461257

Influence of Cholesterol on the Oxygen Permeability of Membranes: Insight from Atomistic Simulations.

Science.gov (United States)

Dotson, Rachel J; Smith, Casey R; Bueche, Kristina; Angles, Gary; Pias, Sally C

2017-06-06

Cholesterol is widely known to alter the physical properties and permeability of membranes. Several prior works have implicated cell membrane cholesterol as a barrier to tissue oxygenation, yet a good deal remains to be explained with regard to the mechanism and magnitude of the effect. We use molecular dynamics simulations to provide atomic-resolution insight into the influence of cholesterol on oxygen diffusion across and within the membrane. Our simulations show strong overall agreement with published experimental data, reproducing the shapes of experimental oximetry curves with high accuracy. We calculate the upper-limit transmembrane oxygen permeability of a 1-palmitoyl,2-oleoylphosphatidylcholine phospholipid bilayer to be 52 ± 2 cm/s, close to the permeability of a water layer of the same thickness. With addition of cholesterol, the permeability decreases somewhat, reaching 40 ± 2 cm/s at the near-saturating level of 62.5 mol % cholesterol and 10 ± 2 cm/s in a 100% cholesterol mimic of the experimentally observed noncrystalline cholesterol bilayer domain. These reductions in permeability can only be biologically consequential in contexts where the diffusional path of oxygen is not water dominated. In our simulations, cholesterol reduces the overall solubility of oxygen within the membrane but enhances the oxygen transport parameter (solubility-diffusion product) near the membrane center. Given relatively low barriers to passing from membrane to membrane, our findings support hydrophobic channeling within membranes as a means of cellular and tissue-level oxygen transport. In such a membrane-dominated diffusional scheme, the influence of cholesterol on oxygen permeability is large enough to warrant further attention. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Effect of cryoprotectants for maintaining drug permeability barriers in porcine buccal mucosa

DEFF Research Database (Denmark)

Marxen, Eva; Axelsen, Mary Carlos; Pedersen, Anne Marie Lynge

2016-01-01

fresh or frozen/thawed tissue was determined using modified Ussing chambers. Haematoxylin-eosin stained tissue sections for histology were prepared. The permeability of nicotine across tissue frozen without cryoprotectants was significantly higher compared to tissue frozen with cryoprotectants or fresh...

Pathophysiology of increased intestinal permeability in obstructive jaundice

Science.gov (United States)

Assimakopoulos, Stelios F; Scopa, Chrisoula D; Vagianos, Constantine E

2007-01-01

Despite advances in preoperative evaluation and postoperative care, intervention, especially surgery, for relief of obstructive jaundice still carries high morbidity and mortality rates, mainly due to sepsis and renal dysfunction. The key event in the pathophysiology of obstructive jaundice-associated complications is endotoxemia of gut origin because of intestinal barrier failure. This breakage of the gut barrier in obstructive jaundice is multi-factorial, involving disruption of the immunologic, biological and mechanical barrier. Experimental and clinical studies have shown that obstructive jaundice results in increased intestinal permeability. The mechanisms implicated in this phenomenon remain unresolved, but growing research interest during the last decade has shed light in our knowledge in the field. This review summarizes the current concepts in the pathophysiology of obstructive jaundice-induced gut barrier dysfunction, analyzing pivotal factors, such as altered intestinal tight junctions expression, oxidative stress and imbalance of enterocyte proliferation and apoptosis. Clinicians handling patients with obstructive jaundice should not neglect protecting the intestinal barrier function before, during and after intervention for the relief of this condition, which may improve their patients’ outcome. PMID:18161914

Practical Application of Sheet Lead for Sound Barriers.

Science.gov (United States)

Lead Industries Association, New York, NY.

Techniques for improving sound barriers through the use of lead sheeting are described. To achieve an ideal sound barrier a material should consist of the following properties--(1) high density, (2) freedom from stiffness, (3) good damping capacity, and (4) integrity as a non-permeable membrane. Lead combines these desired properties to a greater…

Fibronectin changes in eosinophilic meningitis with blood-CSF barrier disruption.

Science.gov (United States)

Shyu, Ling-Yuh; Hu, Ming-E; Chou, Chun-Hui; Chen, Ke-Min; Chiu, Ping-Sung; Lai, Shih-Chan

2015-01-01

Fibronectin, which is present at relatively low levels in healthy central nervous systems (CNS), shows increased levels in meningitis. In this study, fibronectin processing was correlated with the increased permeability of the blood-cerebrospinal fluid (CSF) barrier as well as with the formation of eosinophil infiltrates in angiostrongyliasis meningitis. The immunohistochemistry results show matrix metalloproteinase-9 (MMP-9) is localized in the choroid plexus epithelium. Coimmunoprecipitation demonstrated fibronectin strongly binds MMP-9. Furthermore, treatment with the MMP-9 inhibitor GM6001 significantly inhibited fibronectin processing, reduced the blood-CSF barrier permeability, and decreased the eosinophil counts. The decreased fibronectin processing in CSF implies decreased cellular invasion of the subarachnoid space across the blood-CSF barrier. Therefore, increased fibronectin processing may be associated with barrier disruption and participate in the extravasation and migration of eosinophils into the CNS during experimental parasitic infection. Copyright © 2015 Elsevier Inc. All rights reserved.

Healing of corneal epithelial wounds in marine and freshwater fish.

Science.gov (United States)

Ubels, J L; Edelhauser, H F

The corneal epithelium of a fish is in direct contact with the aquatic environment and is a barrier to movement of ions and water into and through the cornea. This tissue layer is thus important in maintenance of corneal transparency. When the epithelium is wounded, its protective function is lost and corneal transparency remains compromised until the epithelial barrier is re-established. This study was undertaken to investigate the healing response of the fish cornea to epithelial abrasion. Wounds were stained with fluorescein and photographed during healing. Wound areas were measured by planimetry. The cornea of the sculpin, a marine teleost, becomes edematous after wounding and heals at 2.54 to 3.42 mm2/hr. Nonswelling corneas of the elasmobranchs--dogfish shark and skate--heal at 1.29 mm2/hr, respectively. The wounded eye of the rainbow trout, a freshwater teleost, is stressed by the low osmolality of the environment. Severe corneal edema and cataracts develop following epithelial wounding, and the cornea heals at 0.64 mm2/hr. Although the healing rates in teleosts differ from those in mammals, histology shows that the corneal healing mechanism is essentially the same in fish and mammals.

Astrocytic TYMP and VEGFA drive blood-brain barrier opening in inflammatory central nervous system lesions.

Science.gov (United States)

Chapouly, Candice; Tadesse Argaw, Azeb; Horng, Sam; Castro, Kamilah; Zhang, Jingya; Asp, Linnea; Loo, Hannah; Laitman, Benjamin M; Mariani, John N; Straus Farber, Rebecca; Zaslavsky, Elena; Nudelman, German; Raine, Cedric S; John, Gareth R

2015-06-01

In inflammatory central nervous system conditions such as multiple sclerosis, breakdown of the blood-brain barrier is a key event in lesion pathogenesis, predisposing to oedema, excitotoxicity, and ingress of plasma proteins and inflammatory cells. Recently, we showed that reactive astrocytes drive blood-brain barrier opening, via production of vascular endothelial growth factor A (VEGFA). Here, we now identify thymidine phosphorylase (TYMP; previously known as endothelial cell growth factor 1, ECGF1) as a second key astrocyte-derived permeability factor, which interacts with VEGFA to induce blood-brain barrier disruption. The two are co-induced NFκB1-dependently in human astrocytes by the cytokine interleukin 1 beta (IL1B), and inactivation of Vegfa in vivo potentiates TYMP induction. In human central nervous system microvascular endothelial cells, VEGFA and the TYMP product 2-deoxy-d-ribose cooperatively repress tight junction proteins, driving permeability. Notably, this response represents part of a wider pattern of endothelial plasticity: 2-deoxy-d-ribose and VEGFA produce transcriptional programs encompassing angiogenic and permeability genes, and together regulate a third unique cohort. Functionally, each promotes proliferation and viability, and they cooperatively drive motility and angiogenesis. Importantly, introduction of either into mouse cortex promotes blood-brain barrier breakdown, and together they induce severe barrier disruption. In the multiple sclerosis model experimental autoimmune encephalitis, TYMP and VEGFA co-localize to reactive astrocytes, and correlate with blood-brain barrier permeability. Critically, blockade of either reduces neurologic deficit, blood-brain barrier disruption and pathology, and inhibiting both in combination enhances tissue preservation. Suggesting importance in human disease, TYMP and VEGFA both localize to reactive astrocytes in multiple sclerosis lesion samples. Collectively, these data identify TYMP as an

Effect of butyrate and fermentation products on epithelial integrity in a mucus-secreting human colon cell line

DEFF Research Database (Denmark)

Nielsen, Ditte Søvsø Gundelund; Jensen, Bent Borg; Theil, Peter Kappel

2018-01-01

. This was associated with regulation of different genes involved in epithelial integrity, mucus secretion, apoptosis, oxidative stress, and butyrate transport. In conclusion, butyrate in concentrations that can be achieved by dietary intervention in vivo enhanced the epithelial barrier function in vitro. B...

A plate reader-based method for cell water permeability measurement

DEFF Research Database (Denmark)

Fenton, Robert A.; Moeller, H B; Nielsen, S

2010-01-01

Cell volume and water permeability measurements in cultured mammalian cells are typically conducted under a light microscope. Many of the employed approaches are time consuming and not applicable to a study of confluent epithelial cell monolayers. We present here an adaptation of a calcein......: AQP2-S256D > AQP2 wild-type > AQP2-S256A. We propose that the method can be applied to study AQP function and more generally to study cell volume changes in adherent cell lines. Furthermore, it should be adaptable for AQP inhibitor screening in chemical compound libraries....