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Sample records for epithelial barrier permeability

  1. Polyunsaturated fatty acids support epithelial barrier integrity and reduce IL-4 mediated permeability in vitro.

    Science.gov (United States)

    Willemsen, Linette E M; Koetsier, Marleen A; Balvers, Martin; Beermann, Christopher; Stahl, Bernd; van Tol, Eric A F

    2008-06-01

    The intestinal mucosa functions as a barrier against harmful dietary and microbial antigens. An intact gut barrier forms a prerequisite for protection against infection and allergy. Both allergic and inflammatory mediators (e.g. IL-4, IFN-gamma) are known to compromise the epithelial barrier integrity by enhancing permeability. Breast milk provides protection against infection and allergy and contains polyunsaturated fatty acids (PUFA). Although PUFA are commonly used in infant formulas their effect on intestinal barrier is still poorly understood. Therefore the effects of distinct PUFA (n-6: LA, GLA, DGLA, AA; n-3: ALA, EPA, DHA) and a fat blend with PUFA composition similar to that of the human breast milk fat fraction, on barrier integrity were investigated. Human intestinal epithelial cells (T84) were pre-incubated with individual PUFA or a lipase treated fat blend, with or without subsequent IL-4 exposure. Barrier integrity was evaluated by measuring transepithelial resistance and permeability. Membrane phospholipid composition was determined by capillary gas chromatography. DGLA, AA, EPA, DHA and to a lesser extend GLA enhanced basal TER and strongly reduced IL-4 mediated permeability, while LA and ALA were ineffective. Furthermore, the lipase treated fat blend effectively supported barrier function. PUFA were incorporated in the membrane phospholipid fraction of T84 cells. Long chain PUFA DGLA, AA, EPA and DHA were particularly effective in supporting barrier integrity by improving resistance and reducing IL-4 mediated permeability. Fat blends that release specific PUFA upon digestion in the gastrointestinal tract may support natural resistance.

  2. Local burn injury impairs epithelial permeability and antimicrobial peptide barrier function in distal unburned skin.

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    Plichta, Jennifer K; Droho, Steve; Curtis, Brenda J; Patel, Parita; Gamelli, Richard L; Radek, Katherine A

    2014-06-01

    Our objective was to characterize the mechanisms by which local burn injury compromises epithelial barrier function in burn margin, containing the elements necessary for healing of the burn site, and in distal unburned skin, which serves as potential donor tissue. Experimental mouse scald burn injury. University Research Laboratory. C57/Bl6 Male mice, 8-12 weeks old. To confirm that dehydration was not contributing to our observed barrier defects, in some experiments mice received 1 mL of saline fluid immediately after burn, while a subgroup received an additional 0.5 mL at 4 hours and 1 mL at 24 hours following burn. We then assessed skin pH and transepidermal water loss every 12 hours on the burn wounds for 72 hours postburn. Burn margin exhibited increased epidermal barrier permeability indicated by higher pH, greater transepidermal water loss, and reduced lipid synthesis enzyme expression and structural protein production up to 96 hours postburn. By contrast, antimicrobial peptide production and protease activity were elevated in burn margin. Skin extracts from burn margin did not exhibit changes in the ability to inhibit bacterial growth. However, distal unburned skin from burned mice also demonstrated an impaired response to barrier disruption, indicated by elevated transepidermal water loss and reduced lipid synthesis enzyme and structural protein expression up to 96 hours postburn. Furthermore, skin extracts from distal unburned skin exhibited greater protease activity and a reduced capacity to inhibit bacterial growth of several skin pathogens. Finally, we established that antimicrobial peptide levels were also altered in the lung and bladder, which are common sites of secondary infection in burn-injured patients. These findings reveal several undefined deficiencies in epithelial barrier function at the burn margin, potential donor skin sites, and organs susceptible to secondary infection. These functional and biochemical data provide novel insights into

  3. Polyunsaturated fatty acids support epithelial barrier integrity and reduce IL-4 mediated permeability in vitro.

    NARCIS (Netherlands)

    Willemsen, L.E.M.; Koetsier, Marjolein; Balvers, M.; Beermann, C.; Stahl, B.; Tol, EA van

    2008-01-01

    BACKGROUND: The intestinal mucosa functions as a barrier against harmful dietary and microbial antigens. An intact gut barrier forms a prerequisite for protection against infection and allergy. Both allergic and inflammatory mediators (e.g. IL-4, IFN-gamma) are known to compromise the epithelial

  4. Control the Epithelial Barrier: A Pivotal First Line of Defense

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    Catherine M McKay

    2004-01-01

    Full Text Available Lumen-derived material gains access to the mucosa by permeating between adjacent epithelial cells (ie, paracellular pathway, by transcytosis across the apical and basolateral cell membranes (ie, transcellular pathway or by exploiting breaks or erosions in the epithelium that may, for example, result from inflammation. Increased epithelial permeability (or decreased barrier function has repeatedly been demonstrated in a variety of gut disturbances; notably, in inflammatory bowel disease (IBD. There has been an exponential increase in our knowledge of the structural elements that comprise the epithelial barrier, and of the intrinsic factors (eg, cytokines and external stimuli (eg, bacterial toxins that can either perturb or enhance epithelial permeability. Canadian researchers have been very active in the study of epithelial permeability and have been responsible for major advances in the field, documenting increased permeability in patients with ulcer disease and IBD and some of their first degree relatives (as well as before onset of overt inflammation, and elucidating mechanisms of stress-induced and cytokine-induced increases in permeability (1-8. A recent study from Scott et al (9 continues this impressive tradition.

  5. Erythropoietin protects the retinal pigment epithelial barrier against ...

    African Journals Online (AJOL)

    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 monolayer integrity, RPE barrier permeability, distribution of the junction proteins ZO-1, occludin and the levels of superoxide dismutase (SOD) and malondialdehyde ...

  6. Haemophilia, AIDS and lung epithelial permeability

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    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).

  7. Endocannabinoids modulate human blood–brain barrier permeability in vitro

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    Hind, William H; Tufarelli, Cristina; Neophytou, Maria; Anderson, Susan I; England, Timothy J; O'Sullivan, Saoirse E

    2015-01-01

    Background and Purpose Endocannabinoids alter permeability at various epithelial barriers, and cannabinoid receptors and endocannabinoid levels are elevated by stroke, with potential neuroprotective effects. We therefore explored the role of endocannabinoids in modulating blood–brain barrier (BBB) permeability in normal conditions and in an ischaemia/reperfusion model. Experimental Approach Human brain microvascular endothelial cell and astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. Endocannabinoids or endocannabinoid-like compounds were assessed for their ability to modulate baseline permeability or OGD-induced hyperpermeability. Target sites of action were investigated using receptor antagonists and subsequently identified with real-time PCR. Key Results Anandamide (10 μM) and oleoylethanolamide (OEA, 10 μM) decreased BBB permeability (i.e. increased resistance). This was mediated by cannabinoid CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) channels, calcitonin gene-regulated peptide (CGRP) receptor (anandamide only) and PPARα (OEA only). Application of OEA, palmitoylethanolamide (both PPARα mediated) or virodhamine (all 10 μM) decreased the OGD-induced increase in permeability during reperfusion. 2-Arachidonoyl glycerol, noladin ether and oleamide did not affect BBB permeability in normal or OGD conditions. N-arachidonoyl-dopamine increased permeability through a cytotoxic mechanism. PPARα and γ, CB1 receptors, TRPV1 channels and CGRP receptors were expressed in both cell types, but mRNA for CB2 receptors was only present in astrocytes. Conclusion and Implication The endocannabinoids may play an important modulatory role in normal BBB physiology, and also afford protection to the BBB during ischaemic stroke, through a number of target sites. PMID:25651941

  8. Endocannabinoids modulate human blood-brain barrier permeability in vitro.

    Science.gov (United States)

    Hind, William H; Tufarelli, Cristina; Neophytou, Maria; Anderson, Susan I; England, Timothy J; O'Sullivan, Saoirse E

    2015-06-01

    Endocannabinoids alter permeability at various epithelial barriers, and cannabinoid receptors and endocannabinoid levels are elevated by stroke, with potential neuroprotective effects. We therefore explored the role of endocannabinoids in modulating blood-brain barrier (BBB) permeability in normal conditions and in an ischaemia/reperfusion model. Human brain microvascular endothelial cell and astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. Endocannabinoids or endocannabinoid-like compounds were assessed for their ability to modulate baseline permeability or OGD-induced hyperpermeability. Target sites of action were investigated using receptor antagonists and subsequently identified with real-time PCR. Anandamide (10 μM) and oleoylethanolamide (OEA, 10 μM) decreased BBB permeability (i.e. increased resistance). This was mediated by cannabinoid CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) channels, calcitonin gene-regulated peptide (CGRP) receptor (anandamide only) and PPARα (OEA only). Application of OEA, palmitoylethanolamide (both PPARα mediated) or virodhamine (all 10 μM) decreased the OGD-induced increase in permeability during reperfusion. 2-Arachidonoyl glycerol, noladin ether and oleamide did not affect BBB permeability in normal or OGD conditions. N-arachidonoyl-dopamine increased permeability through a cytotoxic mechanism. PPARα and γ, CB1 receptors, TRPV1 channels and CGRP receptors were expressed in both cell types, but mRNA for CB2 receptors was only present in astrocytes. The endocannabinoids may play an important modulatory role in normal BBB physiology, and also afford protection to the BBB during ischaemic stroke, through a number of target sites. © 2015 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of The British Pharmacological Society.

  9. Dopamine enhances duodenal epithelial permeability via the dopamine D5 receptor in rodent.

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    Feng, X-Y; Zhang, D-N; Wang, Y-A; Fan, R-F; Hong, F; Zhang, Y; Li, Y; Zhu, J-X

    2017-05-01

    The intestinal barrier is made up of epithelial cells and intercellular junctional complexes to regulate epithelial ion transport and permeability. Dopamine (DA) is able to promote duodenal epithelial ion transport through D1-like receptors, which includes subtypes of D1 (D1 R) and D5 (D5 R), but whether D1-like receptors influence the duodenal permeability is unclear. FITC-dextran permeability, short-circuit current (ISC ), Western blot, immunohistochemistry and ELISA were used in human D5 R transgenic mice and hyperendogenous enteric DA (HEnD) rats in this study. Dopamine induced a downward deflection in ISC and an increase in FITC-dextran permeability of control rat duodenum, which were inhibited by the D1-like receptor antagonist, SCH-23390. However, DA decreased duodenal transepithelial resistance (TER), an effect also reversed by SCH-23390. A strong immunofluorescence signal for D5 R, but not D1 R, was observed in the duodenum of control rat. In human D5 R knock-in transgenic mice, duodenal mucosa displayed an increased basal ISC with high FITC-dextran permeability and decreased TER with a lowered expression of tight junction proteins, suggesting attenuated duodenal barrier function in these transgenic mice. D5 R knock-down transgenic mice manifested a decreased basal ISC with lowered FITC-dextran permeability. Moreover, an increased FITC-dextran permeability combined with decreased TER and tight junction protein expression in duodenal mucosa were also observed in HEnD rats. This study demonstrates, for the first time, that DA enhances duodenal permeability of control rat via D5 R, which provides new experimental and theoretical evidence for the influence of DA on duodenal epithelial barrier function. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  10. Clamshell excavation of a permeable reactive barrier

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    Molfetta, Antonio Di; Sethi, Rajandrea

    2006-06-01

    Nowadays, permeable reactive barriers (PRB) are one of the most widespread techniques for the remediation of contaminated aquifers. Over the past 10 years, the use of iron-based PRBs has evolved from innovative to accepted standard practice for the treatment of a variety of groundwater contaminants (ITRC in: Permeable reactive barriers: lessons learned/new directions. The Interstate Technology and Regulatory Council, Permeable Reactive Barriers Team 2005). Although, a variety of excavation methods have been developed, backhoe excavators are often used for the construction of PRBs. The aim of this study is to describe the emplacement of a full-scale PRB and the benefits deriving from the use of a crawler crane equipped with a hydraulic grab (also known as clamshell excavator) in the excavation phases. The studied PRB was designed to remediate a chlorinated hydrocarbons plume at an old industrial landfill site, in Avigliana, near the city of Torino, in Italy. The continuous reactive barrier was designed to be 120 m long, 13 m deep, and 0.6 m thick. The installation of the barrier was accomplished using a clamshell for the excavation of the trench and a guar-gum slurry to support the walls. The performance of this technique was outstanding and allowed the installation of the PRB in 7 days. The degree of precision of the excavation was very high because of the intrinsic characteristics of this excavation tool and of the use of a concrete curb to guide the hydraulic grab. Moreover, the adopted technique permitted a saving of bioslurry thus minimizing the amount of biocide required.

  11. Therapeutic benefits of enhancing permeability barrier for atopic eczema

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    George Man

    2015-06-01

    Full Text Available The regulatory role of epidermal permeability barrier function in cutaneous inflammation has been well appreciated. While barrier disruption induces cutaneous inflammation, improvement of permeability barrier function alleviates inflammation. Studies have demonstrated that improvement of epidermal permeability barrier function not only prevents the development of atopic eczema, but also delays the relapse of these diseases. Moreover, enhancing the epidermal permeability barrier also alleviates atopic eczema. Furthermore, co-applications of barrier enhancing products with glucocorticoids can increase the therapeutic efficacy and reduce the adverse effects of glucocorticoids in the treatment of atopic eczema. Therefore, utilization of permeability barrier enhancing products alone or in combination with glucocorticoids could be a valuable approach in the treatment of atopic eczema. In this review, we discuss the benefits of improving the epidermal permeability barrier in the management of atopic eczema.

  12. Herbal medicines that benefit epidermal permeability barrier function

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    Lizhi Hu

    2015-06-01

    Full Text Available Epidermal permeability barrier function plays a critical role in regulating cutaneous functions. Hence, researchers have been searching for effective and affordable regimens to enhance epidermal permeability barrier function. In addition to topical stratum corneum lipids, peroxisome proliferator-activated receptor, and liver X receptor ligands, herbal medicines have been proven to benefit epidermal permeability barrier function in both normal and diseased skin, including atopic dermatitis, glucocorticoid-induced skin damage, and UVB-damaged skin. The potential mechanisms by which herbal medicines improve the permeability barrier include stimulation of epidermal differentiation, lipid production, antimicrobial peptide expression, and antioxidation. Therefore, utilization of herbal medicines could be a valuable alternative approach to enhance epidermal permeability barrier function in order to prevent and/or treat skin disorders associated with permeability barrier abnormalities.

  13. Pulmonary epithelial permeability in rats with bleomycin-induced pneumonitis

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    Anazawa, Yoshiki; Isawa, Toyoharu; Teshima, Takeo; Miki, Makoto; Motomiya, Masakichi (Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis and Cancer)

    1992-07-01

    This study was performed to investigate the mechanism by which [sup 99m]Tc-DTPA molecules pass through the pulmonary epithelium following inhalation of [sup 99m]Tc-DTPA aerosol. Interstitial pneumonitis was induced in 6-week-old male rats by instilling 1 mg/kg of bleomycin into the trachea. Disappearance of radioactivity from the lungs was measured with a gamma camera every 2 weeks to estimate pulmonary epithelial permeability, and light- and electron-microscopic histopathologic examinations were performed at the same intervals. There was a statistically significant increase in the pulmonary epithelial permeability at 2 weeks after the instillation of bleomycin. However, subsecquent changes in pulmonary epithelial permeability were not uniform; some animals showed recovery and some showed further increase and/or partial recovery. Microscopically, increase in the capillary bed, round cell infiltration, and widening of the interstitial space were observed in addition to the presence of macrophages in the alveolar spaces at 2 weeks. Electron microscopic examination revealed vacuolization, thinning and detachment of the alveolar epithelium, and denudation of the basement membrane. Prominent fibrosis, honeycombing, thinning of the pulmonary epithelium, and increase in collagen fibers were observed after 18 weeks. We consider that vacuolization, thinning, and detachment of the pulmonary epithelium and denudation of the basement membrane are related to the increase in pulmonary epithelial permeability in bleomycin-induced interstitial pneumonitis. (author).

  14. Commensal microbiota-induced microRNA modulates intestinal epithelial permeability through the small GTPase ARF4.

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    Nakata, Kazuaki; Sugi, Yutaka; Narabayashi, Hikari; Kobayakawa, Tetsuro; Nakanishi, Yusuke; Tsuda, Masato; Hosono, Akira; Kaminogawa, Shuichi; Hanazawa, Shigemasa; Takahashi, Kyoko

    2017-09-15

    The intestinal tract contains many commensal bacteria that modulate various physiological host functions. Dysbiosis of commensal bacteria triggers dysfunction of the intestinal epithelial barrier, leading to the induction or aggravation of intestinal inflammation. To elucidate whether microRNA plays a role in commensal microbiome-dependent intestinal epithelial barrier regulation, we compared transcripts in intestinal epithelial cells (IECs) from conventional and germ-free mice and found that commensal bacteria induced the expression of miR-21-5p in IECs. miR-21-5p increased intestinal epithelial permeability and up-regulated ADP ribosylation factor 4 (ARF4), a small GTPase, in the IEC line Caco-2. We also found that ARF4 expression was up-regulated upon suppression of phosphatase and tensin homolog (PTEN) and programmed cell death 4 (PDCD4), which are known miR-21-5p targets, by RNAi. Furthermore, ARF4 expression in epithelial cells of the large intestine was higher in conventional mice than in germ-free mice. ARF4 suppression in the IEC line increased the expression of tight junction proteins and decreased intestinal epithelial permeability. These results indicate that commensal microbiome-dependent miR-21-5p expression in IECs regulates intestinal epithelial permeability via ARF4, which may therefore represent a target for preventing or managing dysfunction of the intestinal epithelial barrier. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Role of airway epithelial barrier dysfunction in pathogenesis of asthma.

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    Gon, Yasuhiro; Hashimoto, Shu

    2018-01-01

    Bronchial asthma is characterized by persistent cough, increased sputum, and repeated wheezing. The pathophysiology underlying these symptoms is the hyper-responsiveness of the airway along with chronic airway inflammation. Repeated injury, repair, and regeneration of the airway epithelium following exposure to environmental factors and inflammation results in histological changes and functional abnormalities in the airway mucosal epithelium; such changes are believed to have a significant association with the pathophysiology of asthma. Damage to the barrier functions of the airway epithelium enhances mucosal permeability of foreign substances in the airway epithelium of patients with asthma. Thus, epithelial barrier fragility is closely involved in releasing epithelial cytokines (e.g., TSLP, IL-25, and IL-33) because of the activation of airway epithelial cells, dendritic cells, and innate group 2 innate lymphoid cells (ILC2). Functional abnormalities of the airway epithelial cells along with the activation of dendritic cells, Th2 cells, and ILC2 form a single immunopathological unit that is considered to cause allergic airway inflammation. Here we use the latest published literature to discuss the potential pathological mechanisms regarding the onset and progressive severity of asthma with regard to the disruption of the airway epithelial function. Copyright © 2017 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  16. MicroRNAs regulate tight junction proteins and modulate epithelial/endothelial barrier functions.

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    Cichon, Christoph; Sabharwal, Harshana; Rüter, Christian; Schmidt, M Alexander

    2014-01-01

    Tightly controlled epithelial and endothelial barriers are a prerequisite for life as these barriers separate multicellular organisms from their environment and serve as first lines of defense. Barriers between neighboring epithelial cells are formed by multiple intercellular junctions including the 'apical junctional complex-AJC' with tight junctions (TJ), adherens junctions (AJ), and desmosomes. TJ consist of tetraspan transmembrane proteins like occludin, various claudins that directly control paracellular permeability, and the 'Junctional Adhesion Molecules' (JAMs). For establishing tight barriers TJ are essential but at the same time have to allow also selective permeability. For this, TJ need to be tightly regulated and controlled. This is organized by a variety of adaptor molecules, i.e., protein kinases, phosphatases and GTPases, which in turn are regulated and fine-tuned involving microRNAs (miRNAs). In this review we summarize available data on the role and targeting of miRNAs in the maintenance of epithelial and/or endothelial barriers.

  17. Celiac Disease: Role of the Epithelial Barrier.

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    Schumann, Michael; Siegmund, Britta; Schulzke, Jörg D; Fromm, Michael

    2017-03-01

    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.

  18. The diffusion-active permeable reactive barrier.

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    Schwarz, Alex O; Rittmann, Bruce E

    2010-03-01

    Using the biogeochemical model CCBATCH, which we expanded to include transport processes, we study a novel approach for the treatment of aquifers contaminated with toxic concentrations of metals, the diffusion-active permeable reactive barrier (DAPRB), which is based on generation of sulfide by Sulfate Reducing Bacteria (SRB) as the groundwater moves through a layered treatment zone. In the DAPRB, layers of low conductivity (low-K) containing reactive materials are intercalated between layers of high conductivity (high-K) that transport the groundwater across the barrier. Because diffusion dominates transport in the reactive layers, microbial communities can take advantage there of the chemical-gradient mechanism for protection from toxicants. The ideal sulfidic DAPRB design includes particulate organic matter (POM) and solid sulfate mineral inside the reactive (low-K) layer. This leads to sulfate reduction and the formation of sulfide ligands that complex with toxic metals, such as Zn(2+) in the high-K layer. We perform a theoretical biogeochemical analysis of the ideal configuration of a DAPRB for treatment of Zn-contaminated groundwater. Our analysis using the expanded CCBATCH confirms the gradient-resistance mechanism for bio-protection, with the ZnS bio-sink forming at the intersection of the Zn and sulfide plumes inside the high-K layers of the DAPRB. The detailed DAPRB analysis also shows that total alkalinity and pH distributions are representative footprints of the two key biogeochemical processes taking place, sulfidogenesis and Zn immobilization as sulfide mineral. This is so because these two reactions consume or produce acidic hydrogen and alkalinity. Additionally, because Zn immobilization is due to ZnS mineral precipitation, the ZnS mineral distribution is a good indicator for the bio-sink. Bio-sinks are located for the most part within the high-K layers, and their exact position depends on the relative magnitude of metal and sulfide fluxes. Finally

  19. Effect of age on pulmonary epithelial permeability in unanesthetized lambs

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    Hutchison, A.A.; McNicol, K.J.; Loughlin, G.M.

    1985-01-01

    Pulmonary epithelial permeability was measured 1) in unanesthetized sheep, and 2) longitudinally in growing lambs. Awake sheep were intubated and a solution of /sup 51/Cr-ethylenediaminetetraacetic acid and /sup 125/I-antipyrine was instilled in the intrathoracic trachea via the nasotracheal tube. Arterial blood was drawn 1-25 minutes after the instillation. The ratios of the counts of /sup 51/Cr to /sup 125/I at 7, 10, and 13 min were calculated and averaged for each animal. Data from six adult sheep showed that the mean +/- SE of the permeability ratio was 0.012 +/- 0.003 and was reproducible over three months. When measured twice within two hours, the second ratio was significantly higher than the first. One hour of general anesthesia with methoxyflurane did not alter the permeability ratio significantly. Ten lambs were studied longitudinally 10 hours and 5, 10, 20, and 30 days after delivery. Within the first 24 hours of life the permeability ratio was, significantly greater than the adult value. At five days there was no significant difference between lambs and adult sheep. Throughout the first month of life, the permeability ratio in lambs remained at at the adult level.

  20. Permeability barrier properties of oral keratinocyte cultures: a model of intact human oral mucosa.

    Science.gov (United States)

    Selvaratnam, L; Cruchley, A T; Navsaria, H; Wertz, P W; Hagi-Pavli, E P; Leigh, I M; Squier, C A; Williams, D M

    2001-07-01

    The aim of this study was to establish whether an in vitro model of human oral mucosa had similar permeability characteristics to normal oral mucosa. Such a model would have considerable value as an alternative to the use of mucosal biopsies in studies of transmucosal drug delivery. Keratinocytes obtained from buccal mucosa, hard palate and abdominal skin were seeded onto inert collagen membranes (Cellagen Discs) or dead de-epidermised dermis (DDED) and grown either as submerged or air-liquid interface cultures. Subsequently the ultrastructural characteristics, permeability to water and barrier lipid content of the epithelial cultures were assessed and compared with samples of intact mucosa and skin. All the cultures stratified into multilayered epithelia and displayed features of differentiation including tonofilaments, desmosomes and membrane coating granules. The permeability characteristics and barrier lipid content of the oral mucosal cultures resembled those of intact mucosa. By contrast, epidermal keratinocytes failed to produce a permeability barrier comparable with that of skin and had low levels of barrier associated lipids. Cultures of human oral mucosal keratinocytes obtained from healthy adults develop similar permeability properties and barrier lipid composition to their site of origin. This model system may be useful for the evaluation of local and systemic oral mucosal drug delivery.

  1. Neutrophils Compromise Retinal Pigment Epithelial Barrier Integrity

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    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.

  2. The blood-retinal barrier permeability in diabetic patients

    DEFF Research Database (Denmark)

    Krogsaa, B; Lund-Andersen, H; Mehlsen, J

    1981-01-01

    By the of aid an extended corpus vitreum fluorophotometric technique, the blood-retinal barrier permeability for fluorescein was studied in diabetologically well characterized patients with insulin dependent diabetes mellitus. The method, which involves simultaneous determination of the fluoresce...

  3. Topical tranexamic acid improves the permeability barrier in rosacea

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    Shaomin Zhong

    2015-06-01

    Conclusion: Topical tranexamic acid could improve the epidermal permeability barrier function and clinical signs of rosacea, likely resulting from inhibition of PAR-2 activation and consequent calcium influx. Thus, tranexamic acid could serve as an adjuvant therapy for rosacea.

  4. Streptococcus pyogenes translocates across an epithelial barrier.

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    Sumitomo, Tomoko

    2017-01-01

    Streptococcus pyogenes is a β-hemolytic organism responsible for a wide variety of human diseases that commonly occur as self-limiting purulent diseases of the pharynx and skin. Although the occurrence of invasive infections by S. pyogenes is rare, mortality rates remain high even with progressive medical therapy. As a prerequisite for causing the severe invasive disease, S. pyogenes must invade underlying sterile tissues by translocating across the epithelial barrier. In this study, streptolysin S and SpeB were identified as the novel factors that facilitate bacterial translocation via degradation of intercellular junctions. Furthermore, we found that S. pyogenes exploits host plasminogen for acceleration of bacterial invasion into deeper tissues via tricellular tight junctions. Here, I would like to show our study on bacterial translocation across the epithelial barrier through paracellular route.

  5. Inflammation and the Intestinal Barrier: Leukocyte–Epithelial Cell Interactions, Cell Junction Remodeling, and Mucosal Repair

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    Luissint, Anny-Claude; Parkos, Charles A.; Nusrat, Asma

    2017-01-01

    The intestinal tract is lined by a single layer of columnar epithelial cells that forms a dynamic, permeable barrier allowing for selective absorption of nutrients, while restricting access to pathogens and food-borne antigens. Precise regulation of epithelial barrier function is therefore required for maintaining mucosal homeostasis and depends, in part, on barrier-forming elements within the epithelium and a balance between pro- and anti-inflammatory factors in the mucosa. Pathologic states, such as inflammatory bowel disease, are associated with a leaky epithelial barrier, resulting in excessive exposure to microbial antigens, recruitment of leukocytes, release of soluble mediators, and ultimately mucosal damage. An inflammatory microenvironment affects epithelial barrier properties and mucosal homeostasis by altering the structure and function of epithelial intercellular junctions through direct and indirect mechanisms. We review our current understanding of complex interactions between the intestinal epithelium and immune cells, with a focus on pathologic mucosal inflammation and mechanisms of epithelial repair. We discuss leukocyte–epithelial interactions, as well as inflammatory mediators that affect the epithelial barrier and mucosal repair. Increased knowledge of communication networks between the epithelium and immune system will lead to tissue-specific strategies for treating pathologic intestinal inflammation. PMID:27436072

  6. Altered permeability barrier structure in cholesteatoma matrix

    DEFF Research Database (Denmark)

    Svane-Knudsen, Viggo; Halkier-Sørensen, Lars; Rasmussen, Gurli

    2002-01-01

    lipid structures filling the intercellular spaces mainly control the barrier function. The barrier in cholesteatoma epithelium is several times thicker than in unaffected skin but presents distinctive features of a defective barrier as seen in other scaling skin diseases. The intercellular spaces appear...... frequently occur. The corneocytes are shed in clusters, not as single cells. Further, lipid droplets and intracellular membranous material are occasionally seen. In spite of these clear signs of barrier dysfunction, it is unknown whether the thickness of the barrier compensates for the defect in barrier...

  7. Interleukin-13 promotes expression of Alix to compromise renal tubular epithelial barrier function.

    Science.gov (United States)

    Xu, Chen; Sun, Guangdong; Yang, Jie; Sun, Qianmei; Tong, Zhaohui

    2015-05-01

    The epithelial barrier dysfunction plays a critical role in a number of kidney diseases. The mechanism is unclear. Alix is a protein involving in protein degradation in epithelial cells. This study aims to investigate that interleukin (IL)-13 inhibits Alix to compromise the kidney epithelial barrier function. In this study, the murine collecting duct cell line (M-1) was cultured in Transwell inserts to investigate the significance of Alix in compromising the epithelial barrier functions. T cell (Teff cells) proliferation assay was employed to assess the antigenicity of ovalbumin (OVA) that was transported across the M-1 monolayer barrier. The results showed that M-1 cells express Alix. Exposure to interleukin (IL)-13 markedly decreased the expression of Alix in M-1 cells, which compromised the M-1 monolayer barrier functions by showing the increases in the permeability to OVA. Over-expression of Alix abolished the IL-13-induced M-1 monolayer barrier dysfunction. Knockdown of Alix significantly increased M-1 monolayer permeability. The OVA collected from the Transwell basal chambers induced the OVA-specific T cell proliferation. We conclude that IL-13 compromises M-1 epithelial barrier functions via inhibiting Alix expression. © 2015 International Federation for Cell Biology.

  8. The mycotoxin patulin increases colonic epithelial permeability in vitro.

    Science.gov (United States)

    Mohan, H M; Collins, D; Maher, S; Walsh, E G; Winter, D C; O'Brien, P J; Brayden, D J; Baird, A W

    2012-11-01

    The gastrointestinal lumen is directly exposed to dietary contaminants, including patulin, a mycotoxin produced by moulds. Patulin is known to increase permeability across intestinal Caco-2 monolayers. This study aimed to determine the effect of patulin on permeability, ion transport and morphology in isolated rat colonic mucosae. Mucosal sheets were mounted in Ussing chambers and voltage clamped. Apical addition of patulin (100-500 μM) rapidly reduced transepithelial electrical resistance (TEER) and increased permeability to [(14)C] mannitol (2.9-fold). Patulin also inhibited carbachol-induced electrogenic chloride secretion and histological evidence of mucosal damage was observed. To examine potential mechanisms of action of patulin on colonic epithelial cells, high-content analysis of Caco-2 cells was performed and this novel, quantitative fluorescence-based approach confirmed its cytotoxic effects. With regard to time course, the cytotoxicity determined by high content analysis took longer than the almost immediate reduction of electrical resistance in isolated mucosal sheets. These data indicate patulin is not only cytotoxic to enterocytes but also has the capacity to directly alter permeability and ion transport in intact intestinal mucosae. These data corroborate and extend findings in intestinal cell culture monolayers, and further suggest that safety limits on consumption of patulin may be warranted. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Microbial products induce claudin-2 to compromise gut epithelial barrier function.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Liu

    Full Text Available The epithelial barrier dysfunction is an important pathogenic feature in a number of diseases. The underlying mechanism is to be further investigated. The present study aims to investigate the role of tight junction protein claudin-2 (Cldn2 in the compromising epithelial barrier function. In this study, the expression of Cldn2 in the epithelial layer of mice and patients with food allergy was observed by immunohistochemistry. The induction of Cldn2 was carried out with a cell culture model. The Cldn2-facilitated antigen internalization was observed by confocal microscopy. The epithelial barrier function in the gut epithelial monolayer was assessed by recording the transepithelial resistance and assessing the permeability to a macromolecular tracer. The results showed that the positive immune staining of Cldn2 was observed in the epithelial layer of the small intestine that was weakly stained in naïve control mice, and strongly stained in sensitized mice as well as patients with food allergy. Exposure to cholera toxin or Staphylococcal enterotoxin B induced the expression of Cldn2 in HT-29 or T84 cells. Cldn2 could bind protein antigen to form complexes to facilitate the antigen transport across the epithelial barrier. Blocking Cldn2 prevented the allergen-related hypersensitivity the intestine. We conclude that the tight junction protein Cldn2 is involved in the epithelial barrier dysfunction.

  10. 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.

  11. 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.

  12. Matrix metalloproteinase 9-induced increase in intestinal epithelial tight junction permeability contributes to the severity of experimental DSS colitis

    Science.gov (United States)

    Nighot, Prashant; Al-Sadi, Rana; Guo, Shuhong; Watterson, D. Martin; Ma, Thomas

    2015-01-01

    Recent studies have implicated a pathogenic role for matrix metalloproteinases 9 (MMP-9) in inflammatory bowel disease. Although loss of epithelial barrier function has been shown to be a key pathogenic factor for the development of intestinal inflammation, the role of MMP-9 in intestinal barrier function remains unclear. The aim of this study was to investigate the role of MMP-9 in intestinal barrier function and intestinal inflammation. Wild-type (WT) and MMP-9−/− mice were subjected to experimental dextran sodium sulfate (DSS) colitis by administration of 3% DSS in drinking water for 7 days. The mouse colonic permeability was measured in vivo by recycling perfusion of the entire colon using fluorescently labeled dextran. The DSS-induced increase in the colonic permeability was accompanied by an increase in intestinal epithelial cell MMP-9 expression in WT mice. The DSS-induced increase in intestinal permeability and the severity of DSS colitis was found to be attenuated in MMP-9−/− mice. The colonic protein expression of myosin light chain kinase (MLCK) and phospho-MLC was found to be significantly increased after DSS administration in WT mice but not in MMP-9−/− mice. The DSS-induced increase in colonic permeability and colonic inflammation was attenuated in MLCK−/− mice and MLCK inhibitor ML-7-treated WT mice. The DSS-induced increase in colonic surface epithelial cell MLCK mRNA was abolished in MMP-9−/− mice. Lastly, increased MMP-9 protein expression was detected within the colonic surface epithelial cells in ulcerative colitis cases. These data suggest a role of MMP-9 in modulation of colonic epithelial permeability and inflammation via MLCK. PMID:26514773

  13. Claudin-18 deficiency is associated with airway epithelial barrier dysfunction and asthma.

    Science.gov (United States)

    Sweerus, Kelly; Lachowicz-Scroggins, Marrah; Gordon, Erin; LaFemina, Michael; Huang, Xiaozhu; Parikh, Mihir; Kanegai, Cindy; Fahy, John V; Frank, James A

    2017-01-01

    Epithelial barrier dysfunction and increased permeability may contribute to antigen sensitization and disease progression in asthma. Claudin-18.1 is the only known lung-specific tight junction protein, but its contribution to airway barrier function or asthma is unclear. We sought to test the hypotheses that claudin-18 is a determinant of airway epithelial barrier function that is downregulated by IL-13 and that claudin-18 deficiency results in increased aeroantigen sensitization and airway hyperresponsiveness. Claudin-18.1 mRNA levels were measured in airway epithelial brushings from healthy controls and patients with asthma. In patients with asthma, claudin-18 levels were compared with a three-gene-mean marker of TH2 inflammation. Airway epithelial permeability changes due to claudin-18 deficiency were measured in 16HBE cells and claudin-18 null mice. The effect of IL-13 on claudin expression was determined in primary human airway epithelial cells and in mice. Airway hyperresponsiveness and serum IgE levels were compared in claudin-18 null and wild-type mice following aspergillus sensitization. Epithelial brushings from patients with asthma (n = 67) had significantly lower claudin-18 mRNA levels than did those from healthy controls (n = 42). Claudin-18 levels were lowest among TH2-high patients with asthma. Loss of claudin-18 was sufficient to impair epithelial barrier function in 16HBE cells and in mouse airways. IL-13 decreased claudin-18 expression in primary human cells and in mice. Claudin-18 null mice had significantly higher serum IgE levels and increased airway responsiveness following intranasal aspergillus sensitization. These data support the hypothesis that claudin-18 is an essential contributor to the airway epithelial barrier to aeroantigens. Furthermore, TH2 inflammation suppresses claudin-18 expression, potentially promoting sensitization and airway hyperresponsiveness. Published by Elsevier Inc.

  14. Potential Retinal Benefits of Dietary Polyphenols Based on Their Permeability across the Blood-Retinal Barrier.

    Science.gov (United States)

    Liu, Yixiang; Liu, Guang-Ming; Cao, Min-Jie; Chen, Qingchou; Sun, Lechang; Ji, Baoping

    2017-04-19

    Whether all dietary polyphenols nourish the eyes via oral supplementation is controversial. Given that passage of dietary polyphenols across the blood-retina barrier (BRB) is the precondition for polyphenols to exhibit ocular benefits, the BRB permeability of polyphenols was assessed in this study. Being common dietary polyphenols in fruits and vegetables, nonanthocyanin flavonoids, anthocyanins, and phenolic acids were investigated. BRB was simulated in vitro by using a differentiated retinal pigment epithelial cell monolayer cultivated on a Transwell culture system. Penetration rate was calculated by quantitatively analyzing the polyphenols in basolateral media. The BRB permeability of different polyphenols obviously (p nonanthocyanin flavonoids > anthocyanins. Glycosylation and methylation improved the BRB permeability of nonanthocyanin flavonoids and anthocyanins. However, instability and carbonylation at the C-4 position severely suppressed the BRB permeability of anthocyanins and nonanthocyanin flavonoids. Moreover, a new metabolite was discovered during penetration of anthocyanins into the BRB. However, hydrophilic phenolic acids exhibited better BRB permeability than hydrophobic ones. Data demonstrate that BRB permeability of polyphenols was determined based on structural characteristics, hydrophilicity, stability, and metabolic changes.

  15. Melt Focusing Along Permeability Barriers in Various Tectonic Settings

    Science.gov (United States)

    Montesi, L. G.; Hebert, L. B.

    2012-12-01

    The lithosphere, cold and rigid, acts as a barrier to the migration of melt from sources in the convecting mantle to the surface. In mid-ocean ridge settings in particular, the contrast between the width of the melt production zone at depths, reaching tens to hundreds of kilometer from the ridge axis, and the zone of crustal accretion, only one or two kilometers wide, points to the presence of an efficient focusing mechanism. The development of a zone impermeable to melt, or permeability barrier, at the base of the thermal boundary layer, and transport of melt in a high porosity channel at the base of this barrier provides a reasonable explanation for this focusing. Applied to various segmented and non-segmented mid-ocean ridges like the ultraslow Southwest Indian Ridge and the ultrafast East Pacific Rise at the Siqueiros transform, this process predicts along-strike variations in crustal thickness that compare favorably with observations. Although the concept of permeability barriers has been discussed mainly in the context of mid-ocean ridges, it may apply to other locations where melting in the upper mantle occurs. Permeability barriers form when ascending melt cools and crystallizes as it enters the thermal boundary layer at the base of the lithosphere. Such a setup is present at subduction zones as melts ascending from the mantle wedge interact with the overriding plate. Convection in the wedge introduces thermal gradients that may focus melt roughly to a point above the transition from a coupled to decoupled slab interface. This location is close to where volcanic arcs are observed. Above mantle plumes, a permeability barrier may develop coincident with the lithosphere-asthenosphere boundary, allowing low-degree melts to stall and form a low-velocity layer that has been observed seismically. To date, the hypothesis of a permeability barrier has been thoroughly tested only in the context of mid-ocean ridges. Whether crystallization would be rapid enough in

  16. 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...

  17. Barrier-protective effects of activated protein C in human alveolar epithelial cells.

    Directory of Open Access Journals (Sweden)

    Ferranda Puig

    Full Text Available Acute lung injury (ALI is a clinical manifestation of respiratory failure, caused by lung inflammation and the disruption of the alveolar-capillary barrier. Preservation of the physical integrity of the alveolar epithelial monolayer is of critical importance to prevent alveolar edema. Barrier integrity depends largely on the balance between physical forces on cell-cell and cell-matrix contacts, and this balance might be affected by alterations in the coagulation cascade in patients with ALI. We aimed to study the effects of activated protein C (APC on mechanical tension and barrier integrity in human alveolar epithelial cells (A549 exposed to thrombin. Cells were pretreated for 3 h with APC (50 µg/ml or vehicle (control. Subsequently, thrombin (50 nM or medium was added to the cell culture. APC significantly reduced thrombin-induced cell monolayer permeability, cell stiffening, and cell contraction, measured by electrical impedance, optical magnetic twisting cytometry, and traction microscopy, respectively, suggesting a barrier-protective response. The dynamics of the barrier integrity was also assessed by western blotting and immunofluorescence analysis of the tight junction ZO-1. Thrombin resulted in more elongated ZO-1 aggregates at cell-cell interface areas and induced an increase in ZO-1 membrane protein content. APC attenuated the length of these ZO-1 aggregates and reduced the ZO-1 membrane protein levels induced by thrombin. In conclusion, pretreatment with APC reduced the disruption of barrier integrity induced by thrombin, thus contributing to alveolar epithelial barrier protection.

  18. Short-Term Effects of Overnight Orthokeratology on Corneal Epithelial Permeability and Biomechanical Properties

    OpenAIRE

    Yeh, Thao N.; Green, Harry M.; Zhou, Yixiu; Pitts, Julie; Kitamata-Wong, Britney; Lee, Sophia; Wang, Shiyin L.; Lin, Meng C.

    2013-01-01

    Increased levels of MMP-9 and alterations to the corneal epithelial superficial cells during overnight orthokeratology suggest that the corneal epithelial permeability and corneal biomechanics may be altered by the treatment. This study analyzes the changes over a 30-night treatment period.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Staphylococcal enterotoxin B suppresses Alix and compromises intestinal epithelial barrier functions.

    Science.gov (United States)

    Yan, Hao; Yi, Haitao; Xia, Lixin; Zhan, Zhenke; He, Weiyi; Cao, Jijuan; Yang, Ping-Chang; Liu, Zhigang

    2014-04-09

    The epithelial barrier dysfunction plays a critical role in the pathogenesis of a broad array of immune diseases. Alix protein is involved in the endolysosome system. This study aims to elucidate the role of Alix in the maintenance of epithelial barrier function. The results showed that Alix was detected in T84 cells at both mRNA and protein levels. Exposure to Staphylococcal enterotoxin B (SEB) markedly suppressed the expression of Alix in T84 cells, which could be blocked by knocking down the Toll like receptor 2. The exposure to SEB did not affect the TER, but markedly increased the permeability of T84 monolayers to OVA; the OVA passing through T84 monolayers still preserved the antigenicity manifesting inducing antigen specific T cells proliferation. Alix protein plays a critical role in the maintenance of the barrier function of T84 monolayers.

  1. Conjugated primary bile salts reduce permeability of endotoxin through intestinal epithelial cells and synergize with phosphatidylcholine in suppression of inflammatory cytokine production

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Schaeckeler, S.; Moser, L.

    2007-01-01

    OBJECTIVE: Endotoxemia was shown to be integral in the pathophysiology of obstructive jaundice. In the current study, the role of conjugated primary bile salts (CPBS) and phosphatidylcholine on the permeability of endotoxin through a layer of intestinal epithelial cells and the consequent......: 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...... of CPBS suppressed the permeability of endotoxins through the intestinal epithelial cell layer significantly. In parallel, apical supplementation of CPBS dose-dependently reduced the basolateral production of all cytokines measured. Apical phosphatidylcholine supplementation enhanced this effect...

  2. Vinculin-dependent Cadherin mechanosensing regulates efficient epithelial barrier formation

    Directory of Open Access Journals (Sweden)

    Floor Twiss

    2012-09-01

    Proper regulation of the formation and stabilization of epithelial cell–cell adhesion is crucial in embryonic morphogenesis and tissue repair processes. Defects in this process lead to organ malformation and defective epithelial barrier function. A combination of chemical and mechanical cues is used by cells to drive this process. We have investigated the role of the actomyosin cytoskeleton and its connection to cell–cell junction complexes in the formation of an epithelial barrier in MDCK cells. We find that the E-cadherin complex is sufficient to mediate a functional link between cell–cell contacts and the actomyosin cytoskeleton. This link involves the actin binding capacity of α-catenin and the recruitment of the mechanosensitive protein Vinculin to tensile, punctate cell–cell junctions that connect to radial F-actin bundles, which we name Focal Adherens Junctions (FAJ. When cell–cell adhesions mature, these FAJs disappear and linear junctions are formed that do not contain Vinculin. The rapid phase of barrier establishment (as measured by Trans Epithelial Electrical Resistance (TER correlates with the presence of FAJs. Moreover, the rate of barrier establishment is delayed when actomyosin contraction is blocked or when Vinculin recruitment to the Cadherin complex is prevented. Enhanced presence of Vinculin increases the rate of barrier formation. We conclude that E-cadherin-based FAJs connect forming cell–cell adhesions to the contractile actomyosin cytoskeleton. These specialized junctions are sites of Cadherin mechanosensing, which, through the recruitment of Vinculin, is a driving force in epithelial barrier formation.

  3. Long-Term Monitoring of Permeable Reactive Barriers - Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Liang, L.

    2001-04-12

    The purpose of this project is to conduct collaborative research to evaluate and maximize the effectiveness of permeable reactive barriers (PRBs) with a broad-based working group including representatives from the U.S. Department of Energy (DOE), U.S. Department of Defense (DoD), and the U.S. Environmental Protection Agency (EPA). The Naval Facilities Engineering Service Center (NFESC) and its project partner, Battelle, are leading the DoD effort with funding from DoD's Environmental Security Technology Certification Program (ESTCP) and Strategic Environmental Research and Development Program (SERDP). Oak Ridge National Laboratory (ORNL) is coordinating the DOE effort with support from Subsurface Contaminant Focus Area (SCFA), a research program under DOEs Office of Science and Technology. The National Risk Management Research Laboratory's Subsurface Protection and Remediation Division is leading EPA's effort. The combined effort of these three agencies allows the evaluation of a large number of sites. Documents generated by this joint project will be reviewed by the participating agencies' principal investigators, the Permeable Barriers Group of the Remediation Technologies Development Forum (RTDF), and the Interstate Technology and Regulatory Cooperation (ITRC). The technical objectives of this project are to collect and review existing field data at selected PRB sites, identify data gaps, conduct additional measurements, and provide recommendations to DOE users on suitable long-term monitoring strategies. The specific objectives are to (1) evaluate geochemical and hydraulic performance of PRBs, (2) develop guidelines for hydraulic and geochemical characterization/monitoring, and (3) devise and implement long-term monitoring strategies through the use of hydrological and geochemical models. Accomplishing these objectives will provide valuable information regarding the optimum configuration and lifetime of barriers at specific sites. It will

  4. Effects of Soybean Agglutinin on Intestinal Barrier Permeability and Tight Junction Protein Expression in Weaned Piglets

    Directory of Open Access Journals (Sweden)

    Xiaodong Zhang

    2011-11-01

    Full Text Available This study was developed to provide further information on the intestinal barrier permeability and the tight junction protein expression in weaned piglets fed with different levels of soybean agglutinin (SBA. Twenty-five weaned crossbred barrows (Duroc × Landrace × Yorkshire were selected and randomly allotted to five groups, each group with five replicates. The piglets in the control group were not fed with leguminous products. 0.05, 0.1, 0.15 and 0.2% SBA was added to the control diet to form four experimental diets, respectively. After the experimental period of 7 days (for each group, all the piglets were anesthetized with excess procaine and slaughtered. The D-lactic acid in plasma and the Ileal mucosa diamine oxidase (DAO was analyzed to observe the change in the intestinal permeability. The tight junction proteins occludin and ZO-1 in the jejunum tissue distribution and relative expression were detected by immunohistochemistry and Western Blot. The results illustrated that a high dose of SBA (0.1–0.2% could increase the intestinal permeability and reduce piglet intestinal epithelial tight junction protein occludin or ZO-1 expression, while low dose of SBA (0.05% of total diet had no significant affects. The contents of DAO, D-lactic acid, occludin or ZO-1, had a linear relationship with the SBA levels (0–0.2% in diets. The high dose SBA (0.1–0.2% could increase the intestinal permeability and reduce piglet intestinal epithelial tight junction protein occludin or ZO-1 expression, while low dose of SBA (0.05% of total diet had no affects.

  5. "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.

  6. Enhancement of tight junctional barrier function by micronutrients: compound-specific effects on permeability and claudin composition.

    Directory of Open Access Journals (Sweden)

    Joanna Mercado

    Full Text Available Amid an increasing number of reports in the literature concerning epithelial barrier enhancement by various nutrient compounds, there has never been a study performing side-by-side comparisons of these agents in a single epithelial model. We compare five nutrient compounds (previously reported in various epithelial models to enhance barrier function regarding their ability to increase transepithelial electrical resistance (R(t and decrease transepithelial mannitol permeability (J(m across LLC-PK₁ renal epithelial cell layers. The effects of these nutrients on the abundance of various tight junctional proteins are also compared. In the overall group of nutrients tested--zinc, indole, quercetin, butyrate and nicotine--only nicotine failed to improve barrier function by either parameter. Nicotine also was without effect on tight junctional proteins. Quercetin simultaneously increased R(t and decreased J(m. Zinc, butyrate and indole only exhibited statistically significant enhancement of R(t. Each of these four effective nutrient compounds had unique patterns of effects on the panel of tight junctional proteins studied. No two compounds produced the same pattern of effects. This unique pattern of effects on tight junctional complex composition by each compound establishes the chance for additive or even synergistic improvement of barrier function by combinations of compounds. A synergistic effect of the combination of quercetin and zinc on R(t is shown.

  7. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-03-01

    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.

  9. Simulated Reflux Decreases Vocal Fold Epithelial Barrier Resistance

    Science.gov (United States)

    Erickson, Elizabeth; Sivasankar, Mahalakshmi

    2010-01-01

    Objectives/Hypothesis The vocal fold epithelium provides a barrier to the entry of inhaled and systemic challenges. However, the location of the epithelium makes it vulnerable to damage. Past research suggests, but does not directly demonstrate, that exposure to gastric reflux adversely affects the function of the epithelial barrier. Understanding the nature of reflux-induced epithelial barrier dysfunction is necessary to better recognize the mechanisms for vocal fold susceptibility to this disease. Therefore, we examined the effects of physiologically relevant reflux challenges on vocal fold transepithelial resistance and gross epithelial and subepithelial appearance. Study Design Ex vivo, mixed design with between-group and repeated-measures analyses. Methods Healthy, native porcine vocal folds (N = 52) were exposed to physiologically relevant acidic pepsin, acid-only, or pepsin-only challenges and examined with electrophysiology and light microscopy. For all challenges, vocal folds exposed to a neutral pH served as control. Results Acidic pepsin and acid-only challenges, but not pepsin-only or control challenges significantly reduced transepithelial resistance within 30 minutes. Reductions in transepithelial resistance were irreversible. Challenge exposure produced minimal gross changes in vocal fold epithelial or subepithelial appearance as evidenced by light microscopy. Conclusions These findings demonstrate that acidic environments characteristic of gastric reflux compromise epithelial barrier function without gross structural changes. In healthy, native vocal folds, reductions in transepithelial resistance could reflect reflux-related epithelial disruption. These results might guide the development of pharmacologic and therapeutic recommendations for patients with reflux, such as continued acid-suppression therapy and patient antireflux behavioral education. PMID:20564752

  10. 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.

  11. High Permeability and Intercellular Space Widening With Brimonidine Tartrate Eye Drops in Cultured Stratified Human Corneal Epithelial Sheets.

    Science.gov (United States)

    Hashimoto, Yumi; Yokoo, Seiichi; Usui, Tomohiko; Tsubota, Yukiko; Yamagami, Satoru

    2018-02-01

    To investigate the toxicity of topical glaucoma medications using cultured stratified human corneal epithelial sheets (HCES). HCES were exposed for 30 minutes to the following glaucoma medications: 0.1% brimonidine with sodium chlorite as the preservative, 0.005% latanoprost with 0.02% benzalkonium chloride (BAC) as the preservative, and 0.5% timolol with 0.005% BAC as the preservative. Then, cell viability and barrier function were tested by the WST-1 assay and carboxyfluorescein permeability assay, respectively. After exposure to glaucoma medications, HCES were evaluated by hematoxylin and eosin staining, periodic acid-Schiff staining, scanning electron microscopy, and transmission electron microscopy. HCES exposed to brimonidine showed higher viability and better preservation of cell morphology and microvilli compared with cell sheets exposed to latanoprost or timolol. The carboxyfluorescein permeability assay demonstrated that the barrier function was preserved after HCES were exposed to timolol, but not after exposure to brimonidine or latanoprost. Transmission electron microscopy revealed widening of intercellular junctions with prominent deposits of glycogen or mucopolysaccharide (periodic acid-Schiff positive) after exposure of HCES to brimonidine. The toxicity of 0.1% brimonidine containing sodium chlorite for HCES was lower than that of ophthalmic preparations containing BAC. Reduction of the barrier function occurred after HCES were exposed to brimonidine because of widening of intercellular junctions.

  12. Short communication: Differential loss of bovine mammary epithelial barrier integrity in response to lipopolysaccharide and lipoteichoic acid.

    Science.gov (United States)

    Wellnitz, Olga; Zbinden, Christina; Huang, Xiao; Bruckmaier, Rupert M

    2016-06-01

    In the mammary gland, the blood-milk barrier prevents an uncontrolled intermixture of blood and milk constituents and hence maintains the osmotic gradient to draw water into the mammary secretion. During mastitis, the permeability of the blood-milk barrier is increased, which is reflected by the transfer of blood constituents into milk and vice versa. In this study, we aimed to investigate changes in the barrier function of mammary epithelial cells in vitro as induced by cell wall components of different pathogens. Primary bovine mammary epithelial cells from 3 different cows were grown separately on Transwell (Corning Inc., Corning, NY) inserts. The formation of tight junctions between adjacent epithelial cells was shown by transmission electron microscopy and by immunofluorescence staining of the tight junction protein zona occludens-1. The integrity of the epithelial barrier was assayed by means of transepithelial electrical resistance, as well as by diffusion of the fluorophore Lucifer yellow across the cell layer. The release of lactate dehydrogenase (LDH) was used as an indicator for cytotoxic effects. In response to a 24-h challenge with bacterial endotoxin, barrier integrity was reduced after 3 or 7h, respectively, in response to 0.5mg/mL lipopolysaccharide (LPS) from Escherichia coli or 20mg/mL lipoteichoic acid (LTA) from Staphylococcus aureus. No paracellular leakage was observed in response to 0.2mg/mL LPS or 2mg/mL LTA. Although LPS and LTA affected barrier permeability, most likely by opening the tight junctions, only LPS caused cell damage, reflected by increased LDH concentrations in cell culture medium. These results prove a pathogen-specific loss of blood-milk barrier integrity during mastitis, which is characterized by tight junction opening by both LPS and LTA and by additional epithelial cell destruction through LPS. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Replication of CMV in the gut of HIV-infected individuals and epithelial barrier dysfunction.

    Science.gov (United States)

    Maidji, Ekaterina; Somsouk, Ma; Rivera, Jose M; Hunt, Peter W; Stoddart, Cheryl A

    2017-02-01

    Although invasive cytomegalovirus (CMV) disease is uncommon in the era of antiretroviral therapy (ART), asymptomatic CMV coinfection is nearly ubiquitous in HIV infected individuals. While microbial translocation and gut epithelial barrier dysfunction may promote persistent immune activation in treated HIV infection, potentially contributing to morbidity and mortality, it has been unclear whether CMV replication in individuals with no symptoms of CMV disease might play a role in this process. We hypothesized that persistent CMV replication in the intestinal epithelium of HIV/CMV-coinfected individuals impairs gut epithelial barrier function. Using a combination of state-of-the-art in situ hybridization technology (RNAscope) and immunohistochemistry, we detected CMV DNA and proteins and evidence of intestinal damage in rectosigmoid samples from CMV-positive individuals with both untreated and ART-suppressed HIV infection. Two different model systems, primary human intestinal cells differentiated in vitro to form polarized monolayers and a humanized mouse model of human gut, together demonstrated that intestinal epithelial cells are fully permissive to CMV replication. Independent of HIV, CMV disrupted tight junctions of polarized intestinal cells, significantly reducing transepithelial electrical resistance, a measure of monolayer integrity, and enhancing transepithelial permeability. The effect of CMV infection on the intestinal epithelium is mediated, at least in part, by the CMV-induced proinflammatory cytokine IL-6. Furthermore, letermovir, a novel anti-CMV drug, dampened the effects of CMV on the epithelium. Together, our data strongly suggest that CMV can disrupt epithelial junctions, leading to bacterial translocation and chronic inflammation in the gut and that CMV could serve as a target for therapeutic intervention to prevent or treat gut epithelial barrier dysfunction during HIV infection.

  14. Replication of CMV in the gut of HIV-infected individuals and epithelial barrier dysfunction.

    Directory of Open Access Journals (Sweden)

    Ekaterina Maidji

    2017-02-01

    Full Text Available Although invasive cytomegalovirus (CMV disease is uncommon in the era of antiretroviral therapy (ART, asymptomatic CMV coinfection is nearly ubiquitous in HIV infected individuals. While microbial translocation and gut epithelial barrier dysfunction may promote persistent immune activation in treated HIV infection, potentially contributing to morbidity and mortality, it has been unclear whether CMV replication in individuals with no symptoms of CMV disease might play a role in this process. We hypothesized that persistent CMV replication in the intestinal epithelium of HIV/CMV-coinfected individuals impairs gut epithelial barrier function. Using a combination of state-of-the-art in situ hybridization technology (RNAscope and immunohistochemistry, we detected CMV DNA and proteins and evidence of intestinal damage in rectosigmoid samples from CMV-positive individuals with both untreated and ART-suppressed HIV infection. Two different model systems, primary human intestinal cells differentiated in vitro to form polarized monolayers and a humanized mouse model of human gut, together demonstrated that intestinal epithelial cells are fully permissive to CMV replication. Independent of HIV, CMV disrupted tight junctions of polarized intestinal cells, significantly reducing transepithelial electrical resistance, a measure of monolayer integrity, and enhancing transepithelial permeability. The effect of CMV infection on the intestinal epithelium is mediated, at least in part, by the CMV-induced proinflammatory cytokine IL-6. Furthermore, letermovir, a novel anti-CMV drug, dampened the effects of CMV on the epithelium. Together, our data strongly suggest that CMV can disrupt epithelial junctions, leading to bacterial translocation and chronic inflammation in the gut and that CMV could serve as a target for therapeutic intervention to prevent or treat gut epithelial barrier dysfunction during HIV infection.

  15. Permeability and modulation of the intestinal epithelial barrier in vitro

    NARCIS (Netherlands)

    Duizer, E.

    1999-01-01

    The bioavailability of all ingested compounds is to a great extend determined by the ability of these compounds to pass the intestinal epithelium. A high bioavailability is guaranteed for most nutrients and electrolytes since they are actively absorbed by the epithelium. The same

  16. Functional and cytometric examination of different human lung epithelial cell types as drug transport barriers.

    Science.gov (United States)

    Min, Kyoung Ah; Rosania, Gus R; Kim, Chong-Kook; Shin, Meong Cheol

    2016-03-01

    To develop inhaled medications, various cell culture models have been used to examine the transcellular transport or cellular uptake properties of small molecules. For the reproducible high throughput screening of the inhaled drug candidates, a further verification of cell architectures as drug transport barriers can contribute to establishing appropriate in vitro cell models. In the present study, side-by-side experiments were performed to compare the structure and transport function of three lung epithelial cells (Calu-3, normal human bronchial primary cells (NHBE), and NL-20). The cells were cultured on the nucleopore membranes in the air-liquid interface (ALI) culture conditions, with cell culture medium in the basolateral side only, starting from day 1. In transport assays, paracellular transport across all three types of cells appeared to be markedly different with the NHBE or Calu-3 cells, showing low paracellular permeability and high TEER values, while the NL-20 cells showed high paracellular permeability and low TEER. Quantitative image analysis of the confocal microscope sections further confirmed that the Calu-3 cells formed intact cell monolayers in contrast to the NHBE and NL-20 cells with multilayers. Among three lung epithelial cell types, the Calu-3 cell cultures under the ALI condition showed optimal cytometric features for mimicking the biophysical characteristics of in vivo airway epithelium. Therefore, the Calu-3 cell monolayers could be used as functional cell barriers for the lung-targeted drug transport studies.

  17. Blood-retinal barrier permeability versus diabetes duration and retinal morphology in insulin dependent diabetic patients

    DEFF Research Database (Denmark)

    Krogsaa, B; Lund-Andersen, H; Mehlsen, J

    1987-01-01

    The blood-retinal barrier permeability to fluorescein was quantitated in 54 patients (22 females and 32 males) with insulin dependent diabetes mellitus (IDDM) of different duration. Correlation was demonstrated between permeability and diabetes duration. A normal permeability was measured...... in patients with up to ten years diabetes duration. A pathologically increased permeability was measured with ten to 15 years diabetes duration and during the next decade the permeability increased rapidly to 5-10 times the normal value. Onset of diabetes in the decade before and after puberty did not change...... the pattern. However, the pathologically increased permeability after ten years duration of the disease could not be demonstrated in diabetics with onset of the disease after the age of 30 years. The permeability of the blood-retinal barrier correlated well with changes in retinal morphology as seen...

  18. Proteolytic Regulation of the Intestinal Epithelial Barrier: Mechanisms and Interventions

    Science.gov (United States)

    2013-09-01

    spleen and serum. Bacterial translocation as a measure of barrier permeability will be evaluated by qPCR amplification of bacterial DNA extracted ...in colon length (Figure 1B) and substantially reduced colon weights indicative of a watery stool (Figure 1C). Determination of a clinical disease...score (5) based on stool consistency, presence or absence of fecal blood (Sure-Vue Fecal Occult Blood Test) and changes in body weight revealed that

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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...

  1. TNFα/IFNγ Mediated Intestinal Epithelial Barrier Dysfunction Is Attenuated by MicroRNA-93 Downregulation of PTK6 in Mouse Colonic Epithelial Cells.

    Directory of Open Access Journals (Sweden)

    Ricci J Haines

    Full Text Available Since inflammatory bowel diseases (IBD represent significant morbidity and mortality in the US, the need for defining novel drug targets and inflammatory mechanisms would be of considerable benefit. Although protein tyrosine kinase 6 (PTK6, also known as breast tumor kinase BRK has been primarily studied in an oncogenic context, it was noted that PTK6 null mice exhibited significantly enhanced colonic epithelial barrier function. Considering that the inflammatory functions of PTK6 have not yet been explored, we hypothesized that cytokines responsible for mediating IBD, such as TNFα/IFNγ, may solicit the action of PTK6 to alter barrier function. After first assessing critical mediators of TNFα/IFNγ driven epithelial barrier dysfunction, we further explored the possibility of PTK6 in this inflammatory context. In this report, we showed that PTK6 siRNA and PTK6 null young adult mouse colonic epithelial cells (YAMC exhibited significant attenuation of TNFα/IFNγ induced barrier dysfunction as measured by electric cell-substrate impedance sensing (ECIS assay and permeability assays. In addition, PTK6 null cells transfected with PTK6 cDNA displayed restored barrier dysfunction in response to TNFα/IFNγ, while the cells transfected with vector alone showed similar attenuation of barrier dysfunction. Furthermore, using subcellular fractionation and immunocytochemistry experiments, we found that PTK6 plays a role in FoxO1 nuclear accumulation leading to down-regulation of claudin-3, a tight junction protein. Moreover, we searched for relevant miRNA candidates putative for targeting PTK6 in order to identify and assess the impact of microRNA that target PTK6 with respect to TNFα/IFNγ induced barrier dysfunction. Subsequently, we assayed likely targets and determined their effectiveness in attenuating PTK6 expression as well as cytokine induced barrier dysfunction. Results showed that miR-93 reduced PTK6 expression and attenuated TNF

  2. Change in blood– brain barrier permeability during pediatric diabetic ketoacidosis treatment*

    Science.gov (United States)

    Vavilala, Monica S.; Richards, Todd L.; Roberts, Joan S.; Chiu, Harvey; Pihoker, Catherine; Bradford, Heidi; Deeter, Kristina; Marro, Ken I.; Shaw, Dennis

    2010-01-01

    Objective Cerebral edema is a devastating complication of pediatric diabetic ketoacidosis. We aimed to examine blood– brain barrier permeability during treatment of diabetic ketoacidosis in children. Design Prospective observational study. Setting Seattle Children’s Hospital, Seattle, WA. Patients Children admitted with diabetic ketoacidosis (pH 300 mg/dL, and ketosis). Interventions None. Measurements and Main Results Subjects underwent two serial paired contrast-enhanced perfusion (gadolinium) and diffusion magnetic resonance imaging scans. Change in whole brain and regional blood– brain barrier permeability (permeability ratio*100 and % permeability ratio change) between illness and recovery were determined. Time 0 reflects start of insulin treatment. Thirteen children (median age 10.0 ± 1.1 yrs; seven female) with diabetic ketoacidosis were enrolled. Permeability ratio increased from time 1 (first magnetic resonance image after time 0) to time 2 (second magnetic resonance image after time 0) in the frontal cortex (ten of 13 subjects), occipital cortex (ten of 13 subjects), and basal ganglia (nine of 13). Whole brain permeability ratio increased from time 1 to time 2 (160%) and regional increase in permeability ratio was greatest in the frontal cortex (148%) compared with the occipital cortex (128%) and basal ganglia (112%). Conclusions Overall, whole brain and regional blood– brain barrier permeability increased in most subjects during diabetic ketoacidosis treatment. The frontal region had more blood– brain barrier permeability than other brain regions examined. PMID:19838141

  3. Lactobacillus GG restoration of the gliadin induced epithelial barrier disruption: the role of cellular polyamines.

    Science.gov (United States)

    Orlando, Antonella; Linsalata, Michele; Notarnicola, Maria; Tutino, Valeria; Russo, Francesco

    2014-01-31

    Celiac disease is characterized by enhanced intestinal paracellular permeability due to alterations of function and expression of tight junction (TJ) proteins including ZO-1, Claudin-1 and Occludin. Polyamines are pivotal in the control of intestinal barrier function and are also involved in the regulation of intercellular junction proteins. Different probiotic strains may inhibit gliadin-induced toxic effects and the Lactobacillus rhamnosus GG (L.GG) is effective in the prevention and treatment of gastrointestinal diseases. Aims of the study were to establish in epithelial Caco-2 cells whether i) gliadin affects paracellular permeability and polyamine profile; ii) co-administration of viable L.GG, heat-killed L.GG (L.GG-HK) or its conditioned medium (L.GG-CM) preserves the intestinal epithelial barrier integrity. Additionally, the effects of L.GG on TJ protein expression were tested in presence or absence of polyamines. Administration of gliadin (1 mg/ml) to Caco-2 cells for 6 h caused a significant alteration of paracellular permeability as demonstrated by the rapid decrease in transepithelial resistance with a concomitant zonulin release. These events were followed by a significant increase in lactulose paracellular transport and a slight lowering in ZO-1 and Occludin expression without affecting Claudin-1. Besides, the single and total polyamine content increased significantly. The co-administration of viable L.GG (10(8) CFU/ml), L.GG-HK and L.GG-CM with gliadin significantly restored barrier function as demonstrated by transepithelial resistance, lactulose flux and zonulin release. Viable L.GG and L.GG-HK, but not L.GG-CM, led to a significant reduction in the single and total polyamine levels. Additionally, only the co-administration of viable L.GG with gliadin significantly increased ZO-1, Claudin-1 and Occludin gene expression compared to control cells. When Caco-2 cells treated with viable L.GG and gliadin were deprived in the polyamine content by

  4. Metallic oxide nanoparticle translocation across the human bronchial epithelial barrier.

    Science.gov (United States)

    George, Isabelle; Naudin, Grégoire; Boland, Sonja; Mornet, Stéphane; Contremoulins, Vincent; Beugnon, Karine; Martinon, Laurent; Lambert, Olivier; Baeza-Squiban, Armelle

    2015-03-14

    Inhalation is the most frequent route of unintentional exposure to nanoparticles (NPs). Our aim was to quantify the translocation of different metallic NPs across human bronchial epithelial cells and to determine the factors influencing this translocation. Calu-3 cells forming a tight epithelial barrier when grown on a porous membrane in a two compartment chamber were exposed to fluorescently labelled NPs to quantify the NP translocation. NP translocation and uptake by cells were also studied by confocal and transmission electron microscopy. Translocation was characterized according to NP size (16, 50, or 100 nm), surface charge (negative or positive SiO2), composition (SiO2 or TiO2), presence of proteins or phospholipids and in an inflammatory context. Our results showed that NPs can translocate through the Calu-3 monolayer whatever their composition (SiO2 or TiO2), but this translocation was increased for the smallest and negatively charged NPs. Translocation was not associated with an alteration of the integrity of the epithelial monolayer, suggesting a transcytosis of the internalized NPs. By modifying the NP corona, the ability of NPs to cross the epithelial barrier differed depending on their intrinsic properties, making positively charged NPs more prone to translocate. NP translocation can be amplified by using agents known to open tight junctions and to allow paracellular passage. NP translocation was also modulated when mimicking an inflammatory context frequently found in the lungs, altering the epithelial integrity and inducing transient tight junction opening. This in vitro evaluation of NP translocation could be extended to other inhaled NPs to predict their biodistribution.

  5. Hyperoxia disrupts pulmonary epithelial barrier in newborn rats via the deterioration of occludin and ZO-1

    Directory of Open Access Journals (Sweden)

    You Kai

    2012-05-01

    Full Text Available Abstract Background Prolonged exposure to hyperoxia in neonates can cause hyperoxic acute lung injury (HALI, which is characterized by increased pulmonary permeability and diffuse infiltration of various inflammatory cells. Disruption of the epithelial barrier may lead to altered pulmonary permeability and maintenance of barrier properties requires intact epithelial tight junctions (TJs. However, in neonatal animals, relatively little is known about how the TJ proteins are expressed in the pulmonary epithelium, including whether expression of TJ proteins is regulated in response to hyperoxia exposure. This study determines whether changes in tight junctions play an important role in disruption of the pulmonary epithelial barrier during hyperoxic acute lung injury. Methods Newborn rats, randomly divided into two groups, were exposed to hyperoxia (95% oxygen or normoxia for 1–7 days, and the severity of lung injury was assessed; location and expression of key tight junction protein occludin and ZO-1 were examined by immunofluorescence staining and immunobloting; messenger RNA in lung tissue was studied by RT-PCR; transmission electron microscopy study was performed for the detection of tight junction morphology. Results We found that different durations of hyperoxia exposure caused different degrees of lung injury in newborn rats. Treatment with hyperoxia for prolonged duration contributed to more serious lung injury, which was characterized by increased wet-to-dry ratio, extravascular lung water content, and bronchoalveolar lavage fluid (BALF:serum FD4 ratio. Transmission electron microscopy study demonstrated that hyperoxia destroyed the structure of tight junctions and prolonged hyperoxia exposure, enhancing the structure destruction. The results were compatible with pathohistologic findings. We found that hyperoxia markedly disrupted the membrane localization and downregulated the cytoplasm expression of the key tight junction proteins

  6. Irsogladine maleate regulates gap junctional intercellular communication-dependent epithelial barrier in human nasal epithelial cells.

    Science.gov (United States)

    Miyata, Ryo; Nomura, Kazuaki; Kakuki, Takuya; Takano, Ken-Ichi; Kohno, Takayuki; Konno, Takumi; Sawada, Norimasa; Himi, Tetsuo; Kojima, Takashi

    2015-04-01

    The airway epithelium of the human nasal mucosa acts as the first physical barrier that protects against inhaled substances and pathogens. Irsogladine maleate (IM) is an enhancer of gastric mucosal protective factors via upregulation of gap junctional intercellular communication (GJIC). GJIC is thought to participate in the formation of functional tight junctions. However, the effects of IM on GJIC and the epithelial barrier in human nasal epithelial cells (HNECs) remain unknown. To investigate the effects of IM on GJIC and the tight junctional barrier in HNECs, primary cultures of HNECs transfected with human telomerase reverse transcriptase (hTERT-HNECs) were treated with IM and the GJIC inhibitors oleamide and 18β-GA. Some cells were pretreated with IM before treatment with TLR3 ligand poly(I:C) to examine whether IM prevented the changes via TLR3-mediated signal pathways. In hTERT-HNECs, GJIC blockers reduced the expression of tight junction molecules claudin-1, -4, -7, occludin, tricellulin, and JAM-A. IM induced GJIC activity and enhanced the expression of claudin-1, -4, and JAM-A at the protein and mRNA levels with an increase of barrier function. GJIC blockers prevented the increase of the tight junction proteins induced by IM. Furthermore, IM prevented the reduction of JAM-A but not induction of IL-8 and TNF-α induced by poly(I:C). In conclusion, IM can maintain the GJIC-dependent tight junctional barrier via regulation of GJIC in upper airway nasal epithelium. Therefore, it is possible that IM may be useful as a nasal spray to prevent the disruption of the epithelial barrier by viral infections and exposure to allergens in human nasal mucosa.

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

    Directory of Open Access Journals (Sweden)

    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

  8. Macroporous silicon chips for laterally resolved, multi-parametric analysis of epithelial barrier function.

    Science.gov (United States)

    Michaelis, Stefanie; Rommel, Christina E; Endell, Jan; Göring, Petra; Wehrspohn, Ralf; Steinem, Claudia; Janshoff, Andreas; Galla, Hans-Joachim; Wegener, Joachim

    2012-07-07

    This study describes a novel assay to visualize the macromolecular permeability of epithelial and endothelial cell layers with subcellular lateral resolution. Defects within the cell layer and details about the permeation route of the migrating solute are revealed. The assay is based on silicon chips with densely packed, highly ordered, dead-ended pores of μm-diameters on one side. The cells under study are grown on the porous side of the chip such that the pores in the growth surface serve as an array of femtolitre-sized cuvettes in which the permeating probe accumulates at the site of permeation. The pattern of pore filling reveals the permeability characteristics of the cell layer with a lateral resolution in the μm range. Coating of the chip surface with a thin layer of gold allows for impedance analysis of the adherent cells in order to measure their tightness for inorganic ions at the same time. The new assay provides an unprecedented look on epithelial and endothelial barrier function.

  9. Blood-brain barrier permeability imaging using perfusion computed tomography

    Directory of Open Access Journals (Sweden)

    Avsenik Jernej

    2015-06-01

    Full Text Available Background. The blood-brain barrier represents the selective diffusion barrier at the level of the cerebral microvascular endothelium. Other functions of blood-brain barrier include transport, signaling and osmoregulation. Endothelial cells interact with surrounding astrocytes, pericytes and neurons. These interactions are crucial to the development, structural integrity and function of the cerebral microvascular endothelium. Dysfunctional blood-brain barrier has been associated with pathologies such as acute stroke, tumors, inflammatory and neurodegenerative diseases.

  10. 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

    if permeability barriers for small molecules (nicotine and diazepam) were maintained after freezing porcine buccal mucosa with cryoprotectants to -80°C. Combinations of dimethyl sulfoxide, bovine serum albumin, glycerol and sucrose were used as cryoprotectants. The permeability of nicotine and diazepam across...... tissue. Freezing with or without cryoprotectants did not significantly affect the flux of diazepam compared to fresh tissue. Only minor histological changes were seen in frozen/thawed porcine buccal mucosa compared to fresh tissue. In conclusion, permeability barriers for nicotine and diazepam were...

  11. A new function for parietal epithelial cells: a second glomerular barrier.

    Science.gov (United States)

    Ohse, Takamoto; Chang, Alice M; Pippin, Jeffrey W; Jarad, George; Hudkins, Kelly L; Alpers, Charles E; Miner, Jeffrey H; Shankland, Stuart J

    2009-12-01

    The functional role of glomerular parietal epithelial cells (PECs) remains poorly understood. To test the hypothesis that PECs form an impermeable barrier to filtered protein through the formation of tight junctions (TJ), studies were performed in normal animals and in the anti-glomerular basement membrane (GBM) model of crescentic nephritis. Electron microscopy showed well-defined TJ between PECs in normal mice, which no longer could be identified when these cells became extensively damaged or detached from their underlying Bowman's basement membrane. The TJ proteins claudin-1, zonula occludens-1, and occludin stained positive in PECs; however, staining decreased in anti-GBM disease. To show that these events were associated with increased permeability across the PEC-Bowman's basement membrane barrier, control and diseased animals were injected intravenously with either Texas red-conjugated dextran (3 kDa) or ovalbumin (45 kDa) tracers. As expected, both tracers were readily filtered across the glomerular filtration barrier and taken up by proximal tubular cells. However, when the glomerular filtration barrier was injured in anti-GBM disease, tracers were taken up by podocytes and PECs. Moreover, tracers were also detected between PECs and the underlying Bowman's basement membrane, and in many instances were detected in the extraglomerular space. We propose that together with its underlying Bowman's basement membrane, the TJ of PECs serve as a second barrier to protein. When disturbed following PEC injury, the increase in permeability of this layer to filtered protein is a mechanism underlying periglomerular inflammation characteristic of anti-GBM disease.

  12. Epithelial-specific Toll-like Receptor (TLR)5 Activation Mediates Barrier Dysfunction in Experimental Ileitis.

    Science.gov (United States)

    Lopetuso, Loris R; Jia, Ruo; Wang, Xiao-Ming; Jia, Li-Guo; Petito, Valentina; Goodman, Wendy A; Meddings, Jon B; Cominelli, Fabio; Reuter, Brian K; Pizarro, Theresa T

    2017-03-01

    A large body of evidence supports a central role of TLR5 and its natural ligand, flagellin, in Crohn's disease (CD), with the precise mechanism(s) still unresolved. We investigated the role of flagellin/TLR5 in SAMP1/YitFc (SAMP) mice, a spontaneous model of Crohn's disease-like ileitis. Ileal Tlr5 and serum antiflagellin IgG antibodies were increased in SAMP before the onset of inflammation and during established disease; these trends were abrogated in the absence of colonizing commensal bacteria. Irradiated SAMP receiving either wild-type (AKR) or SAMP bone marrow (BM) developed severe ileitis and displayed increased ileal Tlr5 compared with AKR recipients of either SAMP or AKR bone marrow, neither of which conferred ileitis, suggesting that elevated TLR5 in native SAMP is derived primarily from a nonhematopoietic (e.g., epithelial) source. Indeed, ileal epithelial TLR5 in preinflamed SAMP was increased compared with age-matched AKR and germ-free SAMP. TLR5-specific ex vivo activation of SAMP ileal tissues decreased epithelial barrier resistance, indicative of increased permeability, and was accompanied by altered expression of the tight junction proteins, claudin-3, occludin, and zonula occludens-1. Our results provide evidence that aberrant, elevated TLR5 expression is present in the ileal epithelium of SAMP mice, is augmented in the presence of the gut microbiome, and that TLR5 activation in response to bacterial flagellin results in a deficiency to maintain appropriate epithelial barrier integrity. Together, these findings represent a potential mechanistic pathway leading to the exacerbation and perpetuation of chronic gut inflammation in experimental ileitis and possibly, in patients with Crohn's disease.

  13. Epithelial Barrier Regulation by Hypoxia-Inducible Factor.

    Science.gov (United States)

    Glover, Louise E; Colgan, Sean P

    2017-09-01

    Mucosal tissues represent surfaces that are exposed to the outside world and provide a conduit for internal and external communication. Tissues such as the intestine and the lung are lined by layer(s) of epithelial cells that, when organized in three dimensions, provide a critical barrier to the flux of luminal contents. This selective barrier is provided through the regulated expression of junctional proteins and mucins. Tissue oxygen metabolism is central to the maintenance of homeostasis in the mucosa. In some organs (e.g., the colon), low baseline Po2 determines tissue metabolism and results in basal expression of the transcription factor, hypoxia-inducible factor (HIF), which is enhanced after ischemia/inflammation. Recent studies have indicated that HIF contributes fundamentally to the expression of barrier-related genes and in the regulation of barrier-adaptive responses within the mucosa. Here, we briefly review recent literature on the topic of hypoxia and HIF regulation of barrier in mucosal health and during disease.

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

    Science.gov (United States)

    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

  15. Δ9-Tetrahydrocannabinol reverses TNFα-induced increase in airway epithelial cell permeability through CB2 receptors.

    Science.gov (United States)

    Shang, Valerie C M; Kendall, David A; Roberts, Richard E

    2016-11-15

    Despite pharmacological treatment, bronchial hyperresponsiveness continues to deteriorate as airway remodelling persists in airway inflammation. Previous studies have demonstrated that the phytocannabinoid Δ9-tetrahydrocannabinol (THC) reverses bronchoconstriction with an anti-inflammatory action. The aim of this study was to investigate the effects of THC on bronchial epithelial cell permeability after exposure to the pro-inflammatory cytokine, TNFα. Calu-3 bronchial epithelial cells were cultured at air-liquid interface. Changes in epithelial permeability were measured using Transepithelial Electrical Resistance (TEER), then confirmed with a paracellular permeability assay and expression of tight junction proteins by Western blotting. Treatment with THC prevented the TNFα-induced decrease in TEER and increase in paracellular permeability. Cannabinoid CB1 and CB2 receptor-like immunoreactivity was found in Calu-3 cells. Subsequent experiments revealed that pharmacological blockade of CB2, but not CB1 receptor inhibited the THC effect. Selective stimulation of CB2 receptors displayed a similar effect to that of THC. TNFα decreased expression of the tight junction proteins occludin and ZO-1, which was prevented by pre-incubation with THC. These data indicate that THC prevents cytokine-induced increase in airway epithelial permeability through CB2 receptor activation. This highlights that THC, or other cannabinoid receptor ligands, could be beneficial in the prevention of inflammation-induced changes in airway epithelial cell permeability, an important feature of airways diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Epithelial microvilli establish an electrostatic barrier to microbial adhesion.

    Science.gov (United States)

    Bennett, Kaila M; Walker, Sharon L; Lo, David D

    2014-07-01

    Microvilli are membrane extensions on the apical surface of polarized epithelia, such as intestinal enterocytes and tubule and duct epithelia. One notable exception in mucosal epithelia is M cells, which are specialized for capturing luminal microbial particles; M cells display a unique apical membrane lacking microvilli. Based on studies of M cell uptake under different ionic conditions, we hypothesized that microvilli may augment the mucosal barrier by providing an increased surface charge density from the increased membrane surface and associated glycoproteins. Thus, electrostatic charges may repel microbes from epithelial cells bearing microvilli, while M cells are more susceptible to microbial adhesion. To test the role of microvilli in bacterial adhesion and uptake, we developed polarized intestinal epithelial cells with reduced microvilli ("microvillus-minus," or MVM) but retaining normal tight junctions. When tested for interactions with microbial particles in suspension, MVM cells showed greatly enhanced adhesion and uptake of particles compared to microvillus-positive cells. This preference showed a linear relationship to bacterial surface charge, suggesting that microvilli resist binding of microbes by using electrostatic repulsion. Moreover, this predicts that pathogen modification of electrostatic forces may contribute directly to virulence. Accordingly, the effacement effector protein Tir from enterohemorrhagic Escherichia coli O157:H7 expressed in epithelial cells induced a loss of microvilli with consequent enhanced microbial binding. These results provide a new context for microvillus function in the host-pathogen relationship, based on electrostatic interactions. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. Fragility of the permeability barrier of Escherichia coli

    NARCIS (Netherlands)

    Haest, C.W.M.; Gier, J. de; Es, G.A. van; Verkleij, A.J.; Deenen, L.L.M. van

    1972-01-01

    An unsaturated fatty acid requiring auxotroph of Escherichia coli was grown with addition of various unsaturated fatty acids. The permeability of the cells for erythritol appeared to be strongly dependent on the fatty acid incorporated in the membrane lipid. Below certain temperatures, depending on

  18. Bile duct epithelial tight junctions and barrier function

    Science.gov (United States)

    Rao, R.K.; Samak, G.

    2013-01-01

    Bile ducts play a crucial role in the formation and secretion of bile as well as excretion of circulating xenobiotic substances. In addition to its secretory and excretory functions, bile duct epithelium plays an important role in the formation of a barrier to the diffusion of toxic substances from bile into the hepatic interstitial tissue. Disruption of barrier function and toxic injury to liver cells appear to be involved in the pathogenesis of a variety of liver diseases such as primary sclerosing cholangitis, primary biliary cirrhosis and cholangiocarcinoma. Although the investigations into understanding the structure and regulation of tight junctions in gut, renal and endothelial tissues have expanded rapidly, very little is known about the structure and regulation of tight junctions in the bile duct epithelium. In this article we summarize the current understanding of physiology and pathophysiology of bile duct epithelium, the structure and regulation of tight junctions in canaliculi and bile duct epithelia and different mechanisms involved in the regulation of disruption and protection of bile duct epithelial tight junctions. This article will make a case for the need of future investigations toward our understanding of molecular organization and regulation of canalicular and bile duct epithelial tight junctions. PMID:24665411

  19. A claudin-9-based ion permeability barrier is essential for hearing.

    Directory of Open Access Journals (Sweden)

    Yoko Nakano

    2009-08-01

    Full Text Available Hereditary hearing loss is one of the most common birth defects, yet the majority of genes required for audition is thought to remain unidentified. Ethylnitrosourea (ENU-mutagenesis has been a valuable approach for generating new animal models of deafness and discovering previously unrecognized gene functions. Here we report on the characterization of a new ENU-induced mouse mutant (nmf329 that exhibits recessively inherited deafness. We found a widespread loss of sensory hair cells in the hearing organs of nmf329 mice after the second week of life. Positional cloning revealed that the nmf329 strain carries a missense mutation in the claudin-9 gene, which encodes a tight junction protein with unknown biological function. In an epithelial cell line, heterologous expression of wild-type claudin-9 reduced the paracellular permeability to Na+ and K+, and the nmf329 mutation eliminated this ion barrier function without affecting the plasma membrane localization of claudin-9. In the nmf329 mouse line, the perilymphatic K+ concentration was found to be elevated, suggesting that the cochlear tight junctions were dysfunctional. Furthermore, the hair-cell loss in the claudin-9-defective cochlea was rescued in vitro when the explanted hearing organs were cultured in a low-K+ milieu and in vivo when the endocochlear K+-driving force was diminished by deletion of the pou3f4 gene. Overall, our data indicate that claudin-9 is required for the preservation of sensory cells in the hearing organ because claudin-9-defective tight junctions fail to shield the basolateral side of hair cells from the K+-rich endolymph. In the tight-junction complexes of hair cells, claudin-9 is localized specifically to a subdomain that is underneath more apical tight-junction strands formed by other claudins. Thus, the analysis of claudin-9 mutant mice suggests that even the deeper (subapical tight-junction strands have biologically important ion barrier function.

  20. Botulinum Toxin Complex Increases Paracellular Permeability in Intestinal Epithelial Cells via Activation of p38 Mitogen-Activated Protein Kinase

    Science.gov (United States)

    MIYASHITA, Shin-ichiro; SAGANE, Yoshimasa; INUI, Ken; HAYASHI, Shintaro; MIYATA, Keita; SUZUKI, Tomonori; OHYAMA, Tohru; WATANABE, Toshihiro; NIWA, Koichi

    2013-01-01

    ABSTRACT Clostridium botulinum produces a large toxin complex (L-TC) that increases paracellular permeability in intestinal epithelial cells by a mechanism that remains unclear. Here, we show that mitogen-activated protein kinases (MAPKs) are involved in this permeability increase. Paracellular permeability was measured by FITC-dextran flux through a monolayer of rat intestinal epithelial IEC-6 cells, and MAPK activation was estimated from western blots. L-TC of C. botulinum serotype D strain 4947 increased paracellular dextran flux and activated extracellular signal-regulated kinase (ERK), p38, but not c-Jun N-terminal kinase (JNK) in IEC-6 cells. The permeability increase induced by L-TC was abrogated by the p38 inhibitor SB203580. These results indicate that L-TC increases paracellular permeability by activating p38, but not JNK and ERK. PMID:23884081

  1. Pulmonary epithelial permeability: vascular background effects on whole lung and regional half-time values.

    Science.gov (United States)

    Langford, J A; Lewis, C A; Gellert, A R; Tolfree, S E; Rudd, R M

    1986-03-01

    Pulmonary epithelial permeability was first measured by Jones et al. We have adapted their technique for use with a gamma camera. Both regional half-time values and background correction factors vary from apex to base in the lung. Examination of two methods of background correction show: that inter-segmental half-time comparison is possible without applying individual correction factors to regions. the use of a region of interest with similar vascular supply to that of the lung eliminates the need for a background correction technique that relies upon an intravenous injection of radioisotope. The inter-renal area provides such a vascular area.

  2. Strain-Dependent Induction of Human Enterocyte Apoptosis by Blastocystis Disrupts Epithelial Barrier and ZO-1 Organization in a Caspase 3- and 9-Dependent Manner

    Science.gov (United States)

    Teo, Joshua D. W.; Tan, Kevin S. W.

    2014-01-01

    Blastocystis is an emerging protistan parasite colonizing the human intestine. It is frequently reported to cause general intestinal symptoms of vomiting, diarrhea, and abdominal pain. We recently demonstrated that Blastocystis rearranged cytoskeletal proteins and induced intestinal epithelial barrier compromise. The effect of Blastocystis on enterocyte apoptosis is unknown, and a possible link between microbially induced enterocyte apoptosis and increased epithelial permeability has yet to be determined. The aim of this study is to assess if Blastocystis induces human enterocyte apoptosis and whether this effect influences human intestinal epithelial barrier function. Monolayers of polarized human colonic epithelial cell-line Caco-2 were incubated with Blastocystis subtype 7 and subtype 4. Assays for both early and late markers of apoptosis, phosphatidylserine externalization, and nuclear fragmentation, respectively, showed that Blastocystis ST-7, but not ST-4, significantly increased apoptosis in enterocytes, suggesting that Blastocystis exhibits host specificity and strain-to-strain variation in pathogenicity. ST-7 also activated Caco-2 caspases 3 and 9 but not 8. ST-7 induced changes in epithelial resistance, permeability, and tight junction (ZO-1) localization. Pretreatment of Caco-2 monolayers with a pan-caspase inhibitor z-VAD-fmk significantly inhibited these changes. This suggests a role for enterocyte apoptosis in Blastocystis-mediated epithelial barrier compromise in the human intestine. PMID:24822183

  3. Strain-Dependent Induction of Human Enterocyte Apoptosis by Blastocystis Disrupts Epithelial Barrier and ZO-1 Organization in a Caspase 3- and 9-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Zhaona Wu

    2014-01-01

    Full Text Available Blastocystis is an emerging protistan parasite colonizing the human intestine. It is frequently reported to cause general intestinal symptoms of vomiting, diarrhea, and abdominal pain. We recently demonstrated that Blastocystis rearranged cytoskeletal proteins and induced intestinal epithelial barrier compromise. The effect of Blastocystis on enterocyte apoptosis is unknown, and a possible link between microbially induced enterocyte apoptosis and increased epithelial permeability has yet to be determined. The aim of this study is to assess if Blastocystis induces human enterocyte apoptosis and whether this effect influences human intestinal epithelial barrier function. Monolayers of polarized human colonic epithelial cell-line Caco-2 were incubated with Blastocystis subtype 7 and subtype 4. Assays for both early and late markers of apoptosis, phosphatidylserine externalization, and nuclear fragmentation, respectively, showed that Blastocystis ST-7, but not ST-4, significantly increased apoptosis in enterocytes, suggesting that Blastocystis exhibits host specificity and strain-to-strain variation in pathogenicity. ST-7 also activated Caco-2 caspases 3 and 9 but not 8. ST-7 induced changes in epithelial resistance, permeability, and tight junction (ZO-1 localization. Pretreatment of Caco-2 monolayers with a pan-caspase inhibitor z-VAD-fmk significantly inhibited these changes. This suggests a role for enterocyte apoptosis in Blastocystis-mediated epithelial barrier compromise in the human intestine.

  4. Epithelial cell adhesion molecule-1 (ECAM1) is required in the maintenance of corneal epithelial barrier integrity.

    Science.gov (United States)

    Zhou, Jinzi; Jiang, Jian; Wang, Shuhong; Xia, Xiaobo

    2016-01-01

    Corneal epithelial barrier integrity is critical in the maintenance of the corneal homeostasis. The corneal barrier dysfunction may be associated with the pathogenesis of a number of eye diseases. In this study, we assessed the expression of epithelial cell adhesion molecule-1 (ECAM1) in human corneal epithelial cells (HCE). The epithelial barrier function of the corneal epithelial monolayer was determined in Transwells. We found that the HCE cells expressed ECAM1. Knockdown of ECAM1 markedly compromised the HCE monolayer barrier function. A complex of ECAM1, claudin1, and occludin was detected in the HCE monolayers, which was not detected in the ECAM1-null HCE monolayers. Exposure to the proinflammatory cytokine, interleukin-13, inhibited the expression of ECAM1 in HCE cells and compromised the barrier function, which was prevented in the HCE monolayer with the ECAM1 overexpression. In conclusion, ECAM1 is required in the formation of the tight junction complex and maintaining the corneal epithelial barrier function. © 2015 International Federation for Cell Biology.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Váradi, Judit; Harazin, András; Fenyvesi, Ferenc; Réti-Nagy, Katalin; Gogolák, Péter; Vámosi, György; Bácskay, Ildikó; Fehér, Pálma; Ujhelyi, Zoltán; Vasvári, Gábor; Róka, Eszter; Haines, David; Deli, Mária A; Vecsernyés, Miklós

    2017-01-01

    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.

  7. Rapid and reversible enhancement of blood–brain barrier permeability using lysophosphatidic acid

    Science.gov (United States)

    On, Ngoc H; Savant, Sanjot; Toews, Myron; Miller, Donald W

    2013-01-01

    The present study characterizes the effects of lysophosphatidic acid (LPA) on blood–brain barrier (BBB) permeability focusing specifically on the time of onset, duration, and magnitude of LPA-induced changes in cerebrovascular permeability in the mouse using both magnetic resonance imaging (MRI) and near infrared fluorescence imaging (NIFR). Furthermore, potential application of LPA for enhanced drug delivery to the brain was also examined by measuring the brain accumulation of radiolabeled methotrexate. Exposure of primary cultured brain microvessel endothelial cells (BMECs) to LPA produced concentration-dependent increases in permeability that were completely abolished by clostridium toxin B. Administration of LPA disrupted BBB integrity and enhanced the permeability of small molecular weight marker gadolinium diethylenetriaminepentaacetate (Gd-DTPA) contrast agent, the large molecular weight permeability marker, IRdye800cwPEG, and the P-glycoprotein efflux transporter probe, Rhodamine 800 (R800). The increase in BBB permeability occurred within 3 minutes after LPA injection and barrier integrity was restored within 20 minutes. A decreased response to LPA on large macromolecule BBB permeability was observed after repeated administration. The administration of LPA also resulted in 20-fold enhancement of radiolabeled methotrexate in the brain. These studies indicate that administration of LPA in combination with therapeutic agents may increase drug delivery to the brain. PMID:24045401

  8. The relative balance of GM-CSF and TGF-β1 regulates lung epithelial barrier function.

    Science.gov (United States)

    Overgaard, Christian E; Schlingmann, Barbara; Dorsainvil White, StevenClaude; Ward, Christina; Fan, Xian; Swarnakar, Snehasikta; Brown, Lou Ann S; Guidot, David M; Koval, Michael

    2015-06-15

    Lung barrier dysfunction is a cardinal feature of the acute respiratory distress syndrome (ARDS). Alcohol abuse, which increases the risk of ARDS two- to fourfold, induces transforming growth factor (TGF)-β1, which increases epithelial permeability and impairs granulocyte/macrophage colony-stimulating factor (GM-CSF)-dependent barrier integrity in experimental models. We hypothesized that the relative balance of GM-CSF and TGF-β1 signaling regulates lung epithelial barrier function. GM-CSF and TGF-β1 were tested separately and simultaneously for their effects on lung epithelial cell barrier function in vitro. TGF-β1 alone caused an ∼ 25% decrease in transepithelial resistance (TER), increased paracellular flux, and was associated with projections perpendicular to tight junctions ("spikes") containing claudin-18 that colocalized with F-actin. In contrast, GM-CSF treatment induced an ∼ 20% increase in TER, decreased paracellular flux, and showed decreased colocalization of spike-associated claudin-18 with F-actin. When simultaneously administered to lung epithelial cells, GM-CSF antagonized the effects of TGF-β1 on epithelial barrier function in cultured cells. Given this, GM-CSF and TGF-β1 levels were measured in bronchoalveolar lavage (BAL) fluid from patients with ventilator-associated pneumonia and correlated with markers for pulmonary edema and patient outcome. In patient BAL fluid, protein markers of lung barrier dysfunction, serum α2-macroglobulin, and IgM levels were increased at lower ratios of GM-CSF/TGF-β1. Critically, patients who survived had significantly higher GM-CSF/TGF-β1 ratios than nonsurviving patients. This study provides experimental and clinical evidence that the relative balance between GM-CSF and TGF-β1 signaling is a key regulator of lung epithelial barrier function. The GM-CSF/TGF-β1 ratio in BAL fluid may provide a concentration-independent biomarker that can predict patient outcomes in ARDS. Copyright © 2015 the American

  9. 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.

  10. Pathogenesis of permeability barrier abnormalities in the ichthyoses: inherited disorders of lipid metabolism

    Science.gov (United States)

    Elias, Peter M.; Williams, Mary L.; Holleran, Walter M.; Jiang, Yan J.; Schmuth, Matthias

    2010-01-01

    Many of the ichthyoses are associated with inherited disorders of lipid metabolism. These disorders have provided unique models to dissect physiologic processes in normal epidermis and the pathophysiology of more common scaling conditions. In most of these disorders, a permeability barrier abnormality “drives” pathophysiology through stimulation of epidermal hyperplasia. Among primary abnormalities of nonpolar lipid metabolism, triglyceride accumulation in neutral lipid storage disease as a result of a lipase mutation provokes a barrier abnormality via lamellar/nonlamellar phase separation within the extracellular matrix of the stratum corneum (SC). Similar mechanisms account for the barrier abnormalities (and subsequent ichthyosis) in inherited disorders of polar lipid metabolism. For example, in recessive X-linked ichthyosis (RXLI), cholesterol sulfate (CSO4) accumulation also produces a permeability barrier defect through lamellar/nonlamellar phase separation. However, in RXLI, the desquamation abnormality is in part attributable to the plurifunctional roles of CSO4 as a regulator of both epidermal differentiation and corneodesmosome degradation. Phase separation also occurs in type II Gaucher disease (GD; from accumulation of glucosylceramides as a result of to β-glucocerebrosidase deficiency). Finally, failure to assemble both lipids and desquamatory enzymes into nascent epidermal lamellar bodies (LBs) accounts for both the permeability barrier and desquamation abnormalities in Harlequin ichthyosis (HI). The barrier abnormality provokes the clinical phenotype in these disorders not only by stimulating epidermal proliferation, but also by inducing inflammation. PMID:18245815

  11. Treatment of fue diesel with a permeable reactive barrier technology

    Directory of Open Access Journals (Sweden)

    SANTIAGO ALONSO CARDONA GALLO

    2007-01-01

    Full Text Available La investigación estudió el tratamiento de diesel combustibles de producción mexicana contenidos en agua con un sistema de barrera reactiva permeables a escala de laboratorio (siete columnas. Se uso un suelo agrícola como medio reactivo. Se aplico peroxido de hidrógeno al 50% industrial como fuente de oxigeno y nitrógeno en urea al 46% como nutriente. Se caracterizo el medio reactivo con los principales parámetros de interés (humedad, materia orgánica, pH, nitrógeno total, fósforo disponible, clasificación del suelo, conductividad eléctrica, sólidos suspendidos volátiles, densidad real y aparente, porosidad, textura, color, salinidad, conductividad hidráulica, capacidad de campo y densidad de bacterias. Se determinaron las cinéticas de degradación y la capacidad de adsorción del diesel en el medio reactivo. Las barreras reactivas permeables se diseñaron con los resultados cinéticos obtenidos en los reactores por lotes. Las columnas tenían dimensiones de 30 cm de longitud y 10 cm de diámetro. Las cinéticas de determinaron durante 18 días y las columnas se corrieron durante 70 días presentando remociones arriba del 80%. Se usaron concentraciones iniciales de diesel de 15,000 mg/L. Para la modelación de la adsorción se aplicaron las ecuaciones de Freundlich y Langmuir, donde esta ultima presentó un mejor ajuste a los datos a los datos experimentales y una mayor capacidad de adsorción. Para el suministro de los nutrientes y oxigeno se aplico el modelo propuesto por McCarty y la ecuación media para diesel propuesta por Jackson. Se determinó una velocidad de degradación de 0.0908 d-1, un coeficiente de distribución del diesel en el medio reactivo de 0.8 ml/g, una capacidad de adsorción de diesel en el medio reactivo de 13.50 mg/L y un factor de retardo de 3.69

  12. 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

  13. Permeability barriers to embryo cryopreservation of Pectinophora gossypiella (Lepidoptera: Gelechiidae).

    Science.gov (United States)

    Rajamohan, Arun; Rinehart, Joseph P; Foster, Stephen P; Leopold, Roger A

    2013-04-01

    The aim of this study was to develop a method to cryopreserve the embryos of the pink bollworm moth, Pectinophora gossypiella (Saunders). Previously developed dipteran cryopreservation protocols were not directly adaptable to use with the embryos of this lepidopteran species. Physiochemical and electron microscope observations revealed substantial differences in the structure of the chorion, wax layer, and vitelline membrane complex when comparing the cryopreservable embryonic stages of P. gossypiella and dipteran embryos. Thus, the initial steps dealing with dechorionation and permeabilization were ineffective and had to be altered. Exposure to the sodium hypochlorite-based chorion removal step decreased P. gossypiella embryo viability to a very low level. Survival increased and permeability was evident when an alkane wash was used as the first step in the procedure. After the alkane treatment with a surfactant yielded the maximum exchange of cryoprotectant with water as evidenced by a significant lowering of the supercooling point of the cryoprotectant-loaded embryos. The remainder of the cryopreservation and storage recovery protocol for P. gossypiella was similar to those developed for dipteran embryos. Survival of recovered, hatched embryos to adulthood was approximately 7%.

  14. /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

  15. A clay permeable reactive barrier to remove Cs-137 from groundwater: Column experiments.

    Science.gov (United States)

    De Pourcq, K; Ayora, C; García-Gutiérrez, M; Missana, T; Carrera, J

    2015-11-01

    Clay minerals are reputed sorbents for Cs-137 and can be used as a low-permeability material to prevent groundwater flow. Therefore, clay barriers are employed to seal Cs-137 polluted areas and nuclear waste repositories. This work is motivated by cases where groundwater flow cannot be impeded. A permeable and reactive barrier to retain Cs-137 was tested. The trapping mechanism is based on the sorption of cesium on illite-containing clay. The permeability of the reactive material is provided by mixing clay on a matrix of wood shavings. Column tests combined with reactive transport modeling were performed to check both reactivity and permeability. Hydraulic conductivity of the mixture (10(-4) m/s) was sufficient to ensure an adequate hydraulic performance of an eventual barrier excavated in most aquifers. A number of column experiments confirmed Cs retention under different flow rates and inflow solutions. A 1D reactive transport model based on a cation-exchange mechanism was built. It was calibrated with batch experiments for high concentrations of NH4+ and K+ (the main competitors of Cs in the exchange positions). The model predicted satisfactorily the results of the column experiments. Once validated, it was used to investigate the performance and duration of a 2 m thick barrier under different scenarios (flow, clay content, Cs-137 and K concentration). Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 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

    . 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...

  17. Dexou low pH plume baseline permeable reactive barrier options

    Energy Technology Data Exchange (ETDEWEB)

    Phifer, M.A.

    2000-06-20

    The current Environmental Restoration Department (ERD) Permeable Reactive Barrier (PRB) baseline configuration consists of a limestone trench and a granular cast iron trench in series. This report provides information relative to the use of PRB technology for the remediation of the D-Area low pH groundwater plumes.

  18. Topical Hesperidin Improves Epidermal Permeability Barrier Function and Epidermal Differentiation in Normal Murine Skin

    Science.gov (United States)

    Hou, Maihua; Man, Mona; Man, Wenyan; Zhu, Wenyuan; Hupe, Melanie; Park, Kyungho; Crumrine, Debra; Elias, Peter M.; Man, Mao-Qiang

    2012-01-01

    Orange peel extract appears to exhibit beneficial effects on skin whitening, inflammation, UVB protection, as well as keratinocyte proliferation. In the present study, we determine whether topical hesperidin influences epidermal permeability barrier function and its underlying mechanisms. Hairless mice were treated topically with 2% hesperidin or 70% ethanol alone twice daily for 6 days. At the end of treatment, basal barrier function as well as transepidermal water loss (TEWL) was measured 2 and 4 hours post barrier disruption. Epidermal proliferation and differentiation were evaluated by immunohistochemical staining and Western blot analysis. Additionally, lamellar body density and secretion were assessed by electron microscopy. Although there were no significant differences in basal barrier function, in comparison to control animals, topical hesperidin significantly accelerated barrier recovery at both 2 and 4 hours after acute barrier abrogation. Enhanced barrier function in hesperidin-treated skin correlated with stimulation of both epidermal proliferation and differentiation, as well as enhanced lamellar body secretion. These results indicate that topical hesperidin enhances epidermal permeability barrier homeostasis at least in part due to stimulation of epidermal proliferation, differentiation, as well as lamellar body secretion. PMID:22509829

  19. 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.

  20. Redox-active media for permeable reactive barriers

    Energy Technology Data Exchange (ETDEWEB)

    Sivavec, T.M. [General Electric Corp. Research and Development Center, Schenectady, NY (United States); Mackenzie, P.D.; Horney, D.P.; Baghel, S.S.

    1997-12-31

    In this paper, three classes of redox-active media are described and evaluated in terms of their long-term effectiveness in treating TCE-contaminated groundwater in permeable reactive zones. Zero-valent iron, in the form of recycled cast iron filings, the first class, has received considerable attention as a reactive media and has been used in about a dozen pilot- and full-scale subsurface wall installations. Criteria used in selecting commercial sources of granular iron, will be discussed. Two other classes of redox-active media that have not yet seen wide use in pilot- or full-scale installations will also be described: Fe(II) minerals and bimetallic systems. Fe(II) minerals, including magnetite (Fe{sub 3}O{sub 4}), and ferrous sulfide (troilite, FeS), are redox-active and afford TCE reduction rates and product distributions that suggest that they react via a reductive mechanism similar to that which operates in the FeO system. Fe(II) species within the passive oxide layer coating the iron metal may act as electron transfer mediators, with FeO serving as the bulk reductant. Bimetallic systems, the third class of redox-active media, are commonly prepared by plating a second metal onto zero-valent iron (e.g., Ni/Fe and Pd/Fe) and have been shown to accelerate solvent degradation rates relative to untreated iron metal. The long-term effectiveness of this approach, however, has not yet been determined in groundwater treatability tests. The results of a Ni-plated iron column study using site groundwater indicate that a change in reduction mechanism (to catalytic dehydrohalogenation/hydrogenation) accounts for the observed rate enhancement. A significant loss in media reactivity was observed over time, attributable to Ni catalyst deactivation or poisoning. Zero-valent iron systems have not shown similar losses in reactivity in long-term laboratory, pilot or field investigations.

  1. Direct visualization of the arterial wall water permeability barrier using CARS microscopy.

    Science.gov (United States)

    Lucotte, Bertrand M; Powell, Chloe; Knutson, Jay R; Combs, Christian A; Malide, Daniela; Yu, Zu-Xi; Knepper, Mark; Patel, Keval D; Pielach, Anna; Johnson, Errin; Borysova, Lyudmyla; Dora, Kim A; Balaban, Robert S

    2017-05-02

    The artery wall is equipped with a water permeation barrier that allows blood to flow at high pressure without significant water leak. The precise location of this barrier is unknown despite its importance in vascular function and its contribution to many vascular complications when it is compromised. Herein we map the water permeability in intact arteries, using coherent anti-Stokes Raman scattering (CARS) microscopy and isotopic perfusion experiments. Generation of the CARS signal is optimized for water imaging with broadband excitation. We identify the water permeation barrier as the endothelial basolateral membrane and show that the apical membrane is highly permeable. This is confirmed by the distribution of the AQP1 water channel within endothelial membranes. These results indicate that arterial pressure equilibrates within the endothelium and is transmitted to the supporting basement membrane and internal elastic lamina macromolecules with minimal deformation of the sensitive endothelial cell. Disruption of this pressure transmission could contribute to endothelial cell dysfunction in various pathologies.

  2. Cell volume and plasma membrane osmotic water permeability in epithelial cell layers measured by interferometry.

    Science.gov (United States)

    Farinas, J; Verkman, A S

    1996-12-01

    The development of strategies to measure plasma membrane osmotic water permeability (Pf) in epithelial cells has been motivated by the identification of a family of molecular water channels. A general approach utilizing interferometry to measure cell shape and volume was developed and applied to measure Pf in cell layers. The method is based on the cell volume dependence of optical path length (OPL) for a light beam passing through the cell. The small changes in OPL were measured by interferometry. A mathematical model was developed to relate the interference signal to cell volume changes for cells of arbitrary shape and size. To validate the model, a Mach-Zehnder interference microscope was used to image OPL in an Madin Darby Canine Kidney (MDCK) cell layer and to reconstruct the three-dimensional cell shape (OPL resolution Mach-Zehnder interferometer was constructed in which one of two interfering laser beams passed through a flow chamber containing the cell layer. The interference signal in response to an osmotic gradient was analyzed to quantify the time course of relative cell volume. The calculated MDCK cell plasma membrane Pf of 6.1 x 10(-4) cm/s at 24 degrees C agreed with that obtained by interference microscopy and by a total internal reflection fluorescence method. Interferometry was also applied to measure the apical plasma membrane water permeability of intact toad urinary bladder; Pf increased fivefold after forskolin stimulation to 0.04 cm/s at 23 degrees C. These results establish and validate the application of interferometry to quantify cell volume and osmotic water permeability in cell layers.

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

    Energy Technology Data Exchange (ETDEWEB)

    Furth, A.J.; Burke, G.K. [Hayward Baker Inc., Odenton, MD (United States); Deutsch, W.L. Jr. [Roy F. Weston, Inc., West Chester, PA (United States)

    1997-12-31

    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{sup 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{sup 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.

  4. Permeability of the blood-brain barrier to lead.

    Science.gov (United States)

    Bradbury, M W; Deane, R

    1993-01-01

    This review examines the kinetics and possible mechanisms of lead transport into brain across the microvessel endothelium (the blood-brain barrier). Although severe lead poisoning both in neonatal rats and in young children may cause microvessel damage, there is little evidence that there is either damage or even disturbance of specific transport mechanisms at blood leads linear with time up to 4 hours, reaching spaces in relation to plasma of 6.6 - 8.2 ml/100 g in cerebral tissues at one hour. The concentration of free Pb+ in serum is of the order of 10(-12)M, the majority of lead being bound to protein and to sulfhydryl compounds, such as L-cysteine. Transport into brain has been further studied during short vascular perfusion of one cerebral hemisphere of the rat with oxygenated and buffered physiological saline. This allows total control of the fluid perfusing the cerebral microvessels. In the absence of organic ligands for lead, 203Pb entered brain very fast, with a space of 9.7 ml/100 g in frontal cortex at one min. The presence of albumin, L-cysteine or EDTA abolished measurable uptake. Experiments designed to reveal a role for the anion exchanger or calcium channels gave negative results. However, the effects of potassium depolarization and of varying pH indicated that the lead species passively entering the endothelium might be PbOH+. Experiments with various metabolic inhibitors, including vanadate, suggested that Pb uptake in the endothelium is mitigated by active back transport of lead into blood by the Ca-ATPase pump.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Epithelial barrier biology: good fences make good neighbours.

    Science.gov (United States)

    Moens, Emmanuelle; Veldhoen, Marc

    2012-01-01

    The external surfaces of the body, such as the skin and the gastrointestinal mucosal membrane, are an important line of defence preventing the invasion of microorganisms and their products. Mucosal immune cells, especially intraepithelial lymphocytes, are involved in maintaining the integrity of these epithelial barriers. They contribute towards the tolerance to commensal organisms, which occupy these same sites, and to the immune responses against harmful organisms and their products. The composition of the microbiota is influenced by immune cells as well as external environmental factors, especially the use of antibiotics and diet. There is an increasing appreciation that the microbiota affects systemic immune responses in addition to local immunity. Failure to control the occupancy by microorganisms may result in the disruption of the delicate homeostasis between beneficial and harmful microorganisms and contribute to inflammatory pathologies. This review will discuss some of our current understanding of the impact of immune cells and diet on the microbiota. © 2011 The Babraham Institute. Immunology © 2011 Blackwell Publishing Ltd.

  6. Cobalt chloride compromises transepithelial barrier properties of CaCo-2 BBe human gastrointestinal epithelial cell layers.

    Science.gov (United States)

    DiGuilio, K M; Valenzano, M C; Rybakovsky, E; Mullin, J M

    2018-01-05

    Elevation of the transcription factor HIF-1 is a prominent mediator of not only processes that accompany hypoxia, but also the tumor microenvironment and tissue regeneration. This study uses mediators of "chemical hypoxia" to ask the question whether HIF-1α elevation in a healthy epithelial cell layer leads to leakiness in its tight junctional seals. Transepithelial electrical resistance and transepithelial diffusion of 14C-D-mannitol and other radiolabeled probes are used as indicators of transepithelial barrier function of CaCo-2 BBe human gastrointestinal epithelial cell layers cultured on permeable supports. Western immunoblot analyses of integral tight junctional proteins (occludin and claudins) are used as further indicators of barrier function change. Cobalt, an inhibitor of the prolyl hydroxylase enzymes governing HIF-1α breakdown in the cell, induces transepithelial leakiness in CaCo-2 BBe cell layers in a time and concentration-dependent manner. This increased leakiness is accompanied by significant changes in certain specific integral tight junctional (TJ) proteins such as a decreased level of occludin and increased level of claudin-5. Similar results regarding barrier function compromise also occur with other chemical inhibitors of HIF-1α breakdown, namely ciclopiroxolamine (CPX) and dimethyloxalylglycine (DMOG). The increased leak is manifested by both decreased transepithelial electrical resistance (Rt) and increased paracellular diffusion of D-mannitol (Jm). The induced transepithelial leak shows significant size selectivity, consistent with induced effects on TJ permeability. Less-differentiated cell layers were significantly more affected than well-differentiated cell layers regarding induced transepithelial leak. A genetically modified CaCo-2 variant with reduced levels of HIF-1β, showed reduced transepithelial leak in response to cobalt exposure, further indicating that elevation of HIF-1α levels induced by agents of "chemical hypoxia" is

  7. The Interplay between Radioresistant Caco-2 Cells and the Immune System Increases Epithelial Layer Permeability and Alters Signaling Protein Spectrum

    Science.gov (United States)

    Morini, Jacopo; Babini, Gabriele; Barbieri, Sofia; Baiocco, Giorgio; Ottolenghi, Andrea

    2017-01-01

    Colorectal cancer is one of the most frequent type of cancer, with a higher incidence in the developed countries. Colorectal cancer is usually managed with both surgeries, chemotherapy and radiotherapy. Radiotherapy has the well-known advantage of targeting the tumor, minimizing normal tissue exposure. Nevertheless, during radiation treatment, exposure of healthy tissues is of great concern, in particular because of the effects on the intestinal barrier functions and on cells belonging to the immune system. The functional role of intestinal barrier in avoiding paracellular trafficking and controlling bacterial spread from gut it is well known and it is due to the presence of tight junction complexes. However, intestinal barrier is fundamental in participating to the interplay with immune system, especially considering the gut-associated lymphoid tissue. Until few years ago, radiotherapy was considered to bear only a depressive action on the immune system. However, it is now recognized that the release of pro-inflammatory signals and phenotypic changes in tumoral cells due to ionizing radiation could trigger the immune system against the tumor. In this work, we address how intestinal barrier functions are perturbed by X-ray doses in the range 0–10 Gy, focusing on the interplay between tumoral cells and the immune system. To this aim, we adopted a coculture model in which Caco-2 cells can be grown in presence/absence of peripheral blood mononuclear cells (PBMC). We focused our attention on changes in the proliferation, trans-epithelial electrical resistance (TEER), cytokine release, and proteins of the junctional complexes. Our results indicate a high radioresistance of Caco-2 in the investigated dose range, and an increased permeability of the tumoral cell layer due to the presence of PBMC. This is found to be correlated with activation of PBMC, inhibiting the apoptotic pathway, with the enhancement of cytokine release and with variation of tight junction

  8. Etiology of epithelial barrier dysfunction in patients with type 2 inflammatory diseases.

    Science.gov (United States)

    Schleimer, Robert P; Berdnikovs, Sergejs

    2017-06-01

    Epithelial barriers of the skin, gastrointestinal tract, and airway serve common critical functions, such as maintaining a physical barrier against environmental insults and allergens and providing a tissue interface balancing the communication between the internal and external environments. We now understand that in patients with allergic disease, regardless of tissue location, the homeostatic balance of the epithelial barrier is skewed toward loss of differentiation, reduced junctional integrity, and impaired innate defense. Importantly, epithelial dysfunction characterized by these traits appears to pre-date atopy and development of allergic disease. Despite our growing appreciation of the centrality of barrier dysfunction in initiation of allergic disease, many important questions remain to be answered regarding mechanisms disrupting normal barrier function. Although our external environment (proteases, allergens, and injury) is classically thought of as a principal contributor to barrier disruption associated with allergic sensitization, there is a need to better understand contributions of the internal environment (hormones, diet, and circadian clock). Systemic drivers of disease, such as alterations of the endocrine system, metabolism, and aberrant control of developmental signaling, are emerging as new players in driving epithelial dysfunction and allergic predisposition at various barrier sites. Identifying such central mediators of epithelial dysfunction using both systems biology tools and causality-driven laboratory experimentation will be essential in building new strategic interventions to prevent or reverse the process of barrier loss in allergic patients. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  9. New treatments for restoring impaired epidermal barrier permeability: skin barrier repair creams.

    Science.gov (United States)

    Draelos, Zoe Diana

    2012-01-01

    Skin health depends on an intact barrier composed of protein-rich corneocytes surrounded by the lamellar intercellular lipids. This barrier provides waterproof protection for the body, preventing infection, regulating electrolyte balance, maintaining body temperature, and providing a mechanism for sensation. Damage to the skin barrier results in skin disease that can be treated by a variety of externally applied substances, such as ceramides, hyaluronic acid, licorice extracts, dimethicone, petrolatum, and paraffin wax. These substances are found in moisturizers that are sold as cosmetics and in prescriptions as 510(k) devices. This contribution examines the formulation and effect of skin barrier creams. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, R.S.; Sullivan, E.J. [New Mexico Institute of Mining and Technology, Socorro, NM (United States)

    1995-10-01

    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 ({approximately}$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{sup +} or Ca{sup 2+}), and in organic solvents. Surfactant-modified zeolites sorb nonpolar organics (benzene, toluene, xylene, chlorinated aliphatics) via a partitioning mechanism, inorganic cations (Pb{sup 2+}) via ion exchange and surface complexation, and inorganic anions (CrO{sub 4}{sup 2-}, SeO{sub 4}{sup 2-}, SO{sub 4}{sup 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.

  12. The nuclear pore complex core scaffold and permeability barrier: variations of a common theme.

    Science.gov (United States)

    Hayama, Ryo; Rout, Michael P; Fernandez-Martinez, Javier

    2017-06-01

    The study of the nuclear pore complex (NPC) is a fascinating endeavor, as it not only implies uncovering the 'engineering marvel' of its architecture and function, but also provides a key window into a significant evolutionary event: the origin of the eukaryotic cell. The combined efforts of many groups in the field, with the help of novel methodologies and new model organisms, are facilitating a much deeper understanding of this complex assembly. Here we cover recent advances on the characterization of the structure of the NPC scaffold and of the biophysical mechanisms that define the permeability barrier. We identify common architectural and functional principles between those two NPC compartments, expanding the previous protocoatomer hypothesis to suggest possible evolutionary origins for the FG nucleoporins and the NPC permeability barrier. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. 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 paper focuses on two issues in the implementation of calcite permeable reactive barriers for remediating fluoride contaminated water: the impact of the groundwater chemical matrix and CO2 addition on fluoride removal. Column tests comparing pure NaF solutions, synthetic SPL solutions, and actual SPL......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...

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Alix-mediated assembly of the actomyosin-tight junction polarity complex preserves epithelial polarity and epithelial barrier.

    Science.gov (United States)

    Campos, Yvan; Qiu, Xiaohui; Gomero, Elida; Wakefield, Randall; Horner, Linda; Brutkowski, Wojciech; Han, Young-Goo; Solecki, David; Frase, Sharon; Bongiovanni, Antonella; d'Azzo, Alessandra

    2016-06-23

    Maintenance of epithelial cell polarity and epithelial barrier relies on the spatial organization of the actin cytoskeleton and proper positioning/assembly of intercellular junctions. However, how these processes are regulated is poorly understood. Here we reveal a key role for the multifunctional protein Alix in both processes. In a knockout mouse model of Alix, we identified overt structural changes in the epithelium of the choroid plexus and in the ependyma, such as asymmetrical cell shape and size, misplacement and abnormal beating of cilia, blebbing of the microvilli. These defects culminate in excessive cell extrusion, enlargement of the lateral ventricles and hydrocephalus. Mechanistically, we find that by interacting with F-actin, the Par complex and ZO-1, Alix ensures the formation and maintenance of the apically restricted actomyosin-tight junction complex. We propose that in this capacity Alix plays a role in the establishment of apical-basal polarity and in the maintenance of the epithelial barrier.

  16. Alix-mediated assembly of the actomyosin–tight junction polarity complex preserves epithelial polarity and epithelial barrier

    Science.gov (United States)

    Campos, Yvan; Qiu, Xiaohui; Gomero, Elida; Wakefield, Randall; Horner, Linda; Brutkowski, Wojciech; Han, Young-Goo; Solecki, David; Frase, Sharon; Bongiovanni, Antonella; d'Azzo, Alessandra

    2016-01-01

    Maintenance of epithelial cell polarity and epithelial barrier relies on the spatial organization of the actin cytoskeleton and proper positioning/assembly of intercellular junctions. However, how these processes are regulated is poorly understood. Here we reveal a key role for the multifunctional protein Alix in both processes. In a knockout mouse model of Alix, we identified overt structural changes in the epithelium of the choroid plexus and in the ependyma, such as asymmetrical cell shape and size, misplacement and abnormal beating of cilia, blebbing of the microvilli. These defects culminate in excessive cell extrusion, enlargement of the lateral ventricles and hydrocephalus. Mechanistically, we find that by interacting with F-actin, the Par complex and ZO-1, Alix ensures the formation and maintenance of the apically restricted actomyosin–tight junction complex. We propose that in this capacity Alix plays a role in the establishment of apical–basal polarity and in the maintenance of the epithelial barrier. PMID:27336173

  17. Enteric glial cells and their role in the intestinal epithelial barrier.

    Science.gov (United States)

    Yu, Yan-Bo; Li, Yan-Qing

    2014-08-28

    The intestinal epithelium constitutes a physical and functional barrier between the external environment and the host organism. It is formed by a continuous monolayer of intestinal epithelial cells maintained together by intercellular junctional complex, limiting access of pathogens, toxins and xenobiotics to host tissues. Once this barrier integrity is disrupted, inflammatory disorders and tissue injury are initiated and perpetuated. Beneath the intestinal epithelial cells lies a population of astrocyte-like cells that are known as enteric glia. The morphological characteristics and expression markers of these enteric glia cells were identical to the astrocytes of the central nervous system. In the past few years, enteric glia have been demonstrated to have a trophic and supporting relationship with intestinal epithelial cells. Enteric glia lesions and/or functional defects can be involved in the barrier dysfunction. Besides, factors secreted by enteric glia are important for the regulation of gut barrier function. Moreover, enteric glia have an important impact on epithelial cell transcriptome and induce a shift in epithelial cell phenotype towards increased cell adhesion and cell differentiation. Enteric glia can also preserve epithelial barrier against intestinal bacteria insult. In this review, we will describe the current body of evidence supporting functional roles of enteric glia on intestinal barrier.

  18. 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 evi...... 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....

  19. 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 precipitation of chromate and other groundwater constituents, the barrier may have a limited capacity for chromate removal. By performing a column experiment with iron filings it was shown that the capacity was slightly lower at high chromate concentration (500 ppm) in comparison to low concentration (20 ppm...

  20. Design Guidance for Application of Permeable Barriers to Remediate Dissolved Chlorinated Solvents,

    Science.gov (United States)

    1997-02-01

    detector GC gas chromatography GC-FID gas chromatograph-flame ionization detector GE General Electric GX gum xanthan HDPE high-density polyethylene HFB...absence of air bubbles in the column. 44 SECTION 6.0 MODELING TO SUPPORT THE PERMEABLE BARRIER DESIGN Modeling enables an understanding of the...Construction and Quality Control, ASTMSTP 1129. American Society for Testing and Materials, Philadelphia, PA. 94 Chabra, R. P. 1993. Bubbles , Drops and Particles

  1. [Changes in the permeability of the blood-brain barrier to oxythiamine].

    Science.gov (United States)

    Ostrovskiĭ, Iu M; Zimatkina, T I; Oparin, D A

    1985-01-01

    Activity of transketolase was distinctly inhibited in mice brain after simultaneous administration of hydroxythiamine and 3,3-dimethyl-l-phenyl-l-phthalyl acetic acid. The rate of the enzyme inhibition correlated with an increase of the acid concentration in the mixture studied. The data obtained suggest that permeability of blood-brain barrier for hydroxythiamine was altered in simultaneous administration of the vitamin with some biologically active preparations.

  2. Plasma from patients with HELLP syndrome increases blood-brain barrier permeability.

    Science.gov (United States)

    Wallace, Kedra; Tremble, Sarah M; Owens, Michelle Y; Morris, Rachael; Cipolla, Marilyn J

    2015-03-01

    Circulating inflammatory factors and endothelial dysfunction have been proposed to contribute to the pathophysiology of hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. To date, the occurrence of neurological complications in these women has been reported, but few studies have examined whether impairment in blood-brain barrier (BBB) permeability or cerebrovascular reactivity is present in women having HELLP syndrome. We hypothesized that plasma from women with HELLP syndrome causes increased BBB permeability and cerebrovascular dysfunction. Posterior cerebral arteries from female nonpregnant rats were perfused with 20% serum from women with normal pregnancies (n = 5) or women with HELLP syndrome (n = 5), and BBB permeability and vascular reactivity were compared. Plasma from women with HELLP syndrome increased BBB permeability while not changing myogenic tone and reactivity to pressure. Addition of the nitric oxide (NO) synthase inhibitor N(ω)-nitro-L-arginine methyl ester caused constriction of arteries that was not different with the different plasmas nor was dilation to the NO donor sodium nitroprusside different between the 2 groups. However, dilation to the small- and intermediate-conductance, calcium-activated potassium channel activator NS309 was decreased in vessels exposed to HELLP plasma. Thus, increased BBB permeability in response to HELLP plasma was associated with selective endothelial dysfunction. © The Author(s) 2014.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. CRF induces intestinal epithelial barrier injury via the release of mast cell proteases and TNF-α.

    Directory of Open Access Journals (Sweden)

    Elizabeth L Overman

    Full Text Available Psychological stress is a predisposing factor in the onset and exacerbation of important gastrointestinal diseases including irritable bowel syndrome (IBS and the inflammatory bowel diseases (IBD. The pathophysiology of stress-induced intestinal disturbances is known to be mediated by corticotropin releasing factor (CRF but the precise signaling pathways remain poorly understood. Utilizing a porcine ex vivo intestinal model, the aim of this study was to investigate the mechanisms by which CRF mediates intestinal epithelial barrier disturbances.Ileum was harvested from 6-8 week-old pigs, mounted on Ussing Chambers, and exposed to CRF in the presence or absence of various pharmacologic inhibitors of CRF-mediated signaling pathways. Mucosal-to-serosal flux of 4 kDa-FITC dextran (FD4 and transepithelial electrical resistance (TER were recorded as indices of intestinal epithelial barrier function.Exposure of porcine ileum to 0.05-0.5 µM CRF increased (p<0.05 paracellular flux compared with vehicle controls. CRF treatment had no deleterious effects on ileal TER. The effects of CRF on FD4 flux were inhibited with pre-treatment of tissue with the non-selective CRF(1/2 receptor antagonist Astressin B and the mast cell stabilizer sodium cromolyn (10(-4 M. Furthermore, anti-TNF-α neutralizing antibody (p<0.01, protease inhibitors (p<0.01 and the neural blocker tetrodotoxin (TTX inhibited CRF-mediated intestinal barrier dysfunction.These data demonstrate that CRF triggers increases in intestinal paracellular permeability via mast cell dependent release of TNF-α and proteases. Furthermore, CRF-mast cell signaling pathways and increases in intestinal permeability require critical input from the enteric nervous system. Therefore, blocking the deleterious effects of CRF may address the enteric signaling of mast cell degranulation, TNFα release, and protease secretion, hallmarks of IBS and IBD.

  5. Sirt1-Sirt3 axis regulates human blood-brain barrier permeability in response to ischemia

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2018-04-01

    Full Text Available Sirtuin1 (Sirt1 and Sirtuin3 (Sirt3 are two well-characterized members of the silent information regulator 2 (Sir2 family of proteins. Both Sirt1 and Sirt3 have been shown to play vital roles in resistance to cellular stress, but the interaction between these two sirtuins has not been fully determined. In this study, we investigated the role of Sirt1-Sirt3 axis in blood-brain barrier (BBB permeability after ischemia in vitro. Human brain microvascular endothelial cells and astrocytes were co-cultured to model the BBB in vitro and oxygen and glucose deprivation (OGD was performed to mimic ischemia. The results of transepithelial electrical resistance (TEER showed that suppression of Sirt1 via siRNA or salermide significantly decreased BBB permeability, whereas Sirt3 knockdown increased BBB permeability. In addition, Sirt1 was shown to regulate Sirt3 expression after OGD through inhibiting the AMPK-PGC1 pathway. Application of the AMPK inhibitor compound C partially prevented the effects of Sirt1-Sirt3 axis on BBB permeability after OGD. The results of flow cytometry and cytochrome c release demonstrated that Sirt1 and Sirt3 exert opposite effects on OGD-induced apoptosis. Furthermore, suppression of Sirt1 was shown to attenuate mitochondrial reactive oxygen species (ROS generation, which contribute to the Sirt1-Sirt3 axis-induced regulation of BBB permeability and cell damage. In summary, these findings demonstrate that the Sirt1-Sirt3 axis might act as an important modulator in BBB physiology, and could be a therapeutic target for ischemic stroke via regulating mitochondrial ROS generation. Keywords: Stroke, Blood-brain barrier, Sirt1, Sirt3, Mitochondrial ROS

  6. 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.

  7. Permeable bio-reactive barriers to address petroleum hydrocarbon contamination at subantarctic Macquarie Island.

    Science.gov (United States)

    Freidman, Benjamin L; Terry, Deborah; Wilkins, Dan; Spedding, Tim; Gras, Sally L; Snape, Ian; Stevens, Geoffrey W; Mumford, Kathryn A

    2017-05-01

    A reliance on diesel generated power and a history of imperfect fuel management have created a legacy of petroleum hydrocarbon contamination at subantarctic Macquarie Island. Increasing environmental awareness and advances in contaminant characterisation and remediation technology have fostered an impetus to reduce the environmental risk associated with legacy sites. A funnel and gate permeable bio-reactive barrier (PRB) was installed in 2014 to address the migration of Special Antarctic Blend diesel from a spill that occurred in 2002, as well as older spills and residual contaminants in the soil at the Main Power House. The PRB gate comprised of granular activated carbon and natural clinoptilolite zeolite. Petroleum hydrocarbons migrating in the soil water were successfully captured on the reactive materials, with concentrations at the outflow of the barrier recorded as being below reporting limits. The nutrient and iron concentrations delivered to the barrier demonstrated high temporal variability with significant iron precipitation observed across the bed. The surface of the granular activated carbon was largely free from cell attachment while natural zeolite demonstrated patchy biofilm formation after 15 months following PRB installation. This study illustrates the importance of informed material selection at field scale to ensure that adsorption and biodegradation processes are utilised to manage the environmental risk associated with petroleum hydrocarbon spills. This study reports the first installation of a permeable bio-reactive barrier in the subantarctic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Reactive Transport Modeling for Mobilization of Arsenic in a Sediment Downgradient from an Iron Permeable Reactive Barrier

    National Research Council Canada - National Science Library

    Sung-Wook Jeen

    2017-01-01

    ... As. While granular iron permeable reactive barriers (PRBs) can be effective for the treatment of arsenic in groundwater, the mobilization of arsenic in the sediment downgradient of the PRB might be an issue due to the reduced geochemical conditions generated...

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

    Science.gov (United States)

    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.

  10. Plasma from preeclamptic women increases blood-brain barrier permeability: role of vascular endothelial growth factor signaling.

    Science.gov (United States)

    Amburgey, Odül A; Chapman, Abbie C; May, Victor; Bernstein, Ira M; Cipolla, Marilyn J

    2010-11-01

    Circulating factors in preeclamptic women are thought to cause endothelial dysfunction and thereby contribute to the progression of this hypertensive condition. Despite the involvement of neurological complications in preeclampsia, there is a paucity of data regarding the effect of circulating factors on cerebrovascular function. Using a rat model of pregnancy, we investigated blood-brain barrier permeability, myogenic activity, and the influence of endothelial vasodilator mechanisms in cerebral vessels exposed intraluminally to plasma from normal pregnant or preeclamptic women. In addition, the role of vascular endothelial growth factor signaling in mediating changes in permeability in response to plasma was investigated. A 3-hour exposure to 20% normal pregnant or preeclamptic plasma increased blood-brain barrier permeability by ≈6.5- and 18.0-fold, respectively, compared with no plasma exposure (Pvascular endothelial growth factor receptor kinase activity prevented the increase in permeability in response to preeclamptic plasma but had no effect on changes in permeability of vessels exposed to normal pregnant plasma. Circulating factors in preeclamptic plasma did not affect myogenic activity or the influence of endothelium on vascular tone. These findings demonstrate that acute exposure to preeclamptic plasma has little effect on reactivity of cerebral arteries but significantly increases blood-brain barrier permeability. Prevention of increased permeability by inhibition of vascular endothelial growth factor signaling suggests that activation of this pathway may be responsible for increased blood-brain barrier permeability after exposure to preeclamptic plasma.

  11. 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....

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

    Directory of Open Access Journals (Sweden)

    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.

  13. The gut-blood barrier permeability - A new marker in cardiovascular and metabolic diseases?

    Science.gov (United States)

    Ufnal, Marcin; Pham, Kinga

    2017-01-01

    Recent studies suggest that blood-borne metabolites of gut microbiota, such as trimethylamine N-oxide (TMAO) are involved in the aetiology of cardiovascular diseases and may serve as markers of cardiovascular risk. To enter the bloodstream the microbiota-derived molecules need to pass the gut-blood barrier (GBB). The GBB plays an important role in maintaining organism homeostasis. It is a complex multi-layer system which determines the absorption of nutrients, water and many other substances. The integrity and permeability of the GBB may be impaired in numerous diseases including gastrointestinal, metabolic and cardiovascular diseases. Here, we propose that the evaluation of the GBB permeability may have a significant diagnostic potential in cardiovascular and metabolic diseases. Second, we suggest that the GBB permeability is a variable that confounds diagnostic value of new gut microbiota-derived biomarkers such as TMAO. Therefore, cardiovascular risk assessment requires the evaluation of both TMAO and the GBB permeability. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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...

  16. 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

  17. Regional distribution of pulmonary epithelial permeability in normal subjects and patients with asbestosis.

    Science.gov (United States)

    Gellert, A R; Lewis, C A; Langford, J A; Tolfree, S E; Rudd, R M

    1985-10-01

    The overall and regional clearance of an inhaled isotope labelled solute from the lungs was examined on the basis of a 15 minute period of data collection, for which a technique was developed that does not require intravenous injection to correct for blood-tissue background activity. The technique was applied to 52 normal subjects (31 non-smokers and 21 smokers) and to 37 patients with asbestosis (21 non-smokers and 16 smokers). In normal smokers solute clearance was faster in the upper and middle zones, with a mean ratio of T1/2 LB (half time solute clearance from lungs to blood) in the upper two thirds to the lower one third of the lungs of 0.66 (0.28-1.33), compared with 1.24 (0.43-2.77) in normal non-smokers (p less than 0.002). In patients with asbestosis solute clearance was accelerated throughout the lungs even though radiographic abnormalities were limited to lower or lower to middle zones. Regional distribution of clearance was not affected by posture in normal subjects. Overall solute clearance was significantly faster in normal current smokers and in patients with asbestosis than in normal non-smokers (p less than 0.001 respectively). Among patients with asbestosis, smokers had faster overall clearance than non-smokers (p less than 0.01). Among normal non-smokers T1/2 LB was not significantly different between those who had never smoked and ex-smokers. Regional abnormalities in pulmonary epithelial permeability may offer insight into the pathogenesis of interstitial lung diseases and smoking related disorders.

  18. Model-based hypothesis of gut microbe populations and gut/brain barrier permeabilities in the development of regressive autism.

    Science.gov (United States)

    Downs, Ryan; Perna, Jonathon; Vitelli, Andrew; Cook, Daniel; Dhurjati, Prasad

    2014-12-01

    Regressive autism is a devastating disorder affecting children between the ages of 15-30 months. The disorder is characterized by the loss of social interaction and communication ability following otherwise healthy development. In spite of rising autism prevalence, current detection methods and treatment options for this disease are lacking. Therefore, this study introduces a systems-level model, which suggests that gut microbes and intestinal inflammation influence the onset of regressive autism through increasing gut permeability. This computational model provides a framework for quantitative understanding of how imbalances in populations of gut microbes alters the whole-body and brain distributions of neurotoxins produced by GI tract bacteria. Our results indicate that increased levels of the bacteria Bacteroides vulgatus lead to increased brain levels of propionic acid, a neurotoxin which has been known to cause symptoms characteristic of autism when injected into the brain of rats. Our results further indicate that immune response to virulence factors produced by bacteria in the gut leads to increased systemic levels of inflammatory cytokines, such as IL-1β, which significantly alter the permeability of the gut epithelial layer and the blood-brain barrier. Due to the large size of cytokines, however, we predict the time required for concentrations in the brain to stabilize to be on the order of years. This suggests that treatments preventing autism development could be administered after identifying microbial biomarkers of disease but before debilitating brain inflammation leads to regressive autism progression. Future research extending this work could provide new treatment options and diagnostic techniques to help combat regressive autism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. 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.

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

    Science.gov (United States)

    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.

  1. Microbial barrier permeability and thermophysiological and mechanical properties of static dissipative woven fabric system

    Science.gov (United States)

    Schwarz, I.; Rogina-Car, B.; Kopitar, D.

    2017-10-01

    Some of the most significant properties of static dissipative woven fabric systems, in applications where contact of textile material and human body is present, beside antistatic properties are definitely microbial barrier permeability and thermophysiological properties. Application of such materials with associated properties is of great importance in bedding upholstery and comfortable apparel. Based on the conducted relevant tests, according to standardized and newly developed methods, it can be concluded that the such static dissipative woven fabric fulfils all the highly set criteria’s, resulting in a system that can, with certainty, provide the necessary health protection and comfort.

  2. 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...

  3. Surfactants enhance the tight-junction permeability of food allergens in human intestinal epithelial Caco-2 cells.

    Science.gov (United States)

    Mine, Yoshinori; Zhang, Jie Wie

    2003-02-01

    Food additives are responsible for certain allergic types of symptoms. Here Caco-2 cell monolayers were used as a model of the intestinal epithelium for the study of the effect of a food grade surfactant. We determined whether or not the presence of a surfactant enhances the transportation of food allergens across human intestinal epithelial Caco-2 cells. This study investigated sucrose monoester fatty acids, which are a food grade surfactant. As an in vitro model of human epithelial cells, Caco-2 cells were grown in monolayers and exposed to different doses of the surfactant in conjunction with ovomucoid, a major egg white allergen. The integrity of the monolayer was assessed by measuring transepithelial electrical resistance (TEER). The permeability of tight junctions and transport of the antigen were studied. TEER correlated with the permeability of tight junctions. TEER significantly decreased upon exposure to a surfactant, indicating an increase in ovomucoid permeability without degradation. The surfactant induced shortening in microvilli, actin disbandment and structural separation of tight junctions. The results indicate that food grade surfactants can increase the paracellular uptake of food allergens. Copyright 2003 S. Karger AG, Basel

  4. The PTEN phosphatase controls intestinal epithelial cell polarity and barrier function: role in colorectal cancer progression.

    Directory of Open Access Journals (Sweden)

    Marie-Josée Langlois

    2010-12-01

    Full Text Available The PTEN phosphatase acts on phosphatidylinositol 3,4,5-triphosphates resulting from phosphatidylinositol 3-kinase (PI3K activation. PTEN expression has been shown to be decreased in colorectal cancer. Little is known however as to the specific cellular role of PTEN in human intestinal epithelial cells. The aim of this study was to investigate the role of PTEN in human colorectal cancer cells.Caco-2/15, HCT116 and CT26 cells were infected with recombinant lentiviruses expressing a shRNA specifically designed to knock-down PTEN. The impact of PTEN downregulation was analyzed on cell polarization and differentiation, intercellular junction integrity (expression of cell-cell adhesion proteins, barrier function, migration (wound assay, invasion (matrigel-coated transwells and on tumor and metastasis formation in mice. Electron microscopy analysis showed that lentiviral infection of PTEN shRNA significantly inhibited Caco-2/15 cell polarization, functional differentiation and brush border development. A strong reduction in claudin 1, 3, 4 and 8 was also observed as well as a decrease in transepithelial resistance. Loss of PTEN expression increased the spreading, migration and invasion capacities of colorectal cancer cells in vitro. PTEN downregulation also increased tumor size following subcutaneous injection of colorectal cancer cells in nude mice. Finally, loss of PTEN expression in HCT116 and CT26, but not in Caco-2/15, led to an increase in their metastatic potential following tail-vein injections in mice.Altogether, these results indicate that PTEN controls cellular polarity, establishment of cell-cell junctions, paracellular permeability, migration and tumorigenic/metastatic potential of human colorectal cancer cells.

  5. 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.

  6. Hypoxia Inducible Factor (HIF Hydroxylases as Regulators of Intestinal Epithelial Barrier FunctionSummary

    Directory of Open Access Journals (Sweden)

    Mario C. Manresa

    2017-05-01

    Full Text Available Human health is dependent on the ability of the body to extract nutrients, fluids, and oxygen from the external environment while at the same time maintaining a state of internal sterility. Therefore, the cell layers that cover the surface areas of the body such as the lung, skin, and gastrointestinal mucosa provide vital semipermeable barriers that allow the transport of essential nutrients, fluid, and waste products, while at the same time keeping the internal compartments free of microbial organisms. These epithelial surfaces are highly specialized and differ in their anatomic structure depending on their location to provide appropriate and effective site-specific barrier function. Given this important role, it is not surprising that significant disease often is associated with alterations in epithelial barrier function. Examples of such diseases include inflammatory bowel disease, chronic obstructive pulmonary disease, and atopic dermatitis. These chronic inflammatory disorders often are characterized by diminished tissue oxygen levels (hypoxia. Hypoxia triggers an adaptive transcriptional response governed by hypoxia-inducible factors (HIFs, which are repressed by a family of oxygen-sensing HIF hydroxylases. Here, we review recent evidence suggesting that pharmacologic hydroxylase inhibition may be of therapeutic benefit in inflammatory bowel disease through the promotion of intestinal epithelial barrier function through both HIF-dependent and HIF-independent mechanisms. Keywords: Epithelial Barrier, Inflammatory Bowel Disease, Hypoxia, Hypoxia-Inducible Factor (HIF Hydroxylases

  7. Effects of ambient air particulate exposure on blood-gas barrier permeability and lung function

    DEFF Research Database (Denmark)

    Bräuner, Elvira Vaclavik; Mortensen, Jann; Møller, Peter

    2009-01-01

    Particulate air pollution is associated with increased risk of pulmonary diseases and detrimental outcomes related to the cardiovascular system, including altered vessel functions. This study's objective was too evaluate the effects of ambient particle exposure on the blood-gas permeability, lung...... function and Clara cell 16 (CC16) protein release in healthy young subjects. Twenty-nine nonsmokers participated in a randomized, two-factor crossover study with or without biking exercise for 180 min and with 24-h exposure to particle-rich (6169-15,362 particles/cm(3); 7.0-11.6 microg/m(3) PM(2.5); 7.......5-15.8 microg/m(3) PM(10-2.5)) or filtered (91-542 particles/cm(3)) air collected above a busy street. The clearance rate of aerosolized (99m)Tc-labeled diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) was measured as an index for the alveolar epithelial membrane integrity and permeability of the lung blood-gas...

  8. Short-term effects of overnight orthokeratology on corneal epithelial permeability and biomechanical properties.

    Science.gov (United States)

    Yeh, Thao N; Green, Harry M; Zhou, Yixiu; Pitts, Julie; Kitamata-Wong, Britney; Lee, Sophia; Wang, Shiyin L; Lin, Meng C

    2013-06-06

    To investigate the effects of 30 nights of overnight orthokeratology (OOK) on corneal epithelial permeability (Pdc) and corneal biomechanical properties. BE Retainer and Paragon CRT lenses were used. Visits were scheduled approximately 4 hours after awakening at baseline and after 1, 5, 10, 14, and 30 days of treatment. Pdc was measured at baseline and at day 30, whereas corneal biomechanical properties and visual acuities (VAs) were measured at all visits. Thirty-nine neophytes and soft contact lens wearers completed the study. There was no difference in Pdc between baseline (ln[Pdc] [95% confidence interval (CI)] = -2.65 [-2.80 to -2.50]) and day 30 (ln[Pdc][CI] = -2.68 [-2.85 to -2.50]) (P = 0.88). Corneal hysteresis (CH) and corneal resistance factor (CRF) reduced significantly from baseline (CH [CI] = 10.89 [10.59-11.19] mm Hg and CRF [CI] = 10.35 [9.99-10.72] mm Hg) to day 30 (CH [CI] = 10.59 [10.31-10.87] mm Hg and CRF [CI] = 9.58 [9.26-9.89] mm Hg) (P = 0.001 for CH and P < 0.001 for CRF). Posttreatment VA did not reach baseline targets, and the difference was worse with low-contrast letters. Asian individuals (n = 18) had significantly worse VA than non-Asian individuals (n = 21) under most conditions through day 5, and the difference extended through day 14 with low-contrast letters under mesopic conditions. The percentage of participants who achieved 20/20 uncorrected was 17% Asian and 40% non-Asian individuals after day 1 and reached 69% Asian and 83% non-Asian individuals at day 30. Thirty nights of OOK did not alter Pdc when measured 4 hours after awakening. OOK caused CH and CRF to decrease, but the changes were not clinically significant compared with diseased and postsurgical cases. Asian individuals, who had lower baseline CH in this study, responded slower to OOK based on early uncorrected VA and overrefraction measurements.

  9. Tracer kinetic modelling for DCE-MRI quantification of subtle blood-brain barrier permeability.

    Science.gov (United States)

    Heye, Anna K; Thrippleton, Michael J; Armitage, Paul A; Valdés Hernández, Maria Del C; Makin, Stephen D; Glatz, Andreas; Sakka, Eleni; Wardlaw, Joanna M

    2016-01-15

    There is evidence that subtle breakdown of the blood-brain barrier (BBB) is a pathophysiological component of several diseases, including cerebral small vessel disease and some dementias. Dynamic contrast-enhanced MRI (DCE-MRI) combined with tracer kinetic modelling is widely used for assessing permeability and perfusion in brain tumours and body tissues where contrast agents readily accumulate in the extracellular space. However, in diseases where leakage is subtle, the optimal approach for measuring BBB integrity is likely to differ since the magnitude and rate of enhancement caused by leakage are extremely low; several methods have been reported in the literature, yielding a wide range of parameters even in healthy subjects. We hypothesised that the Patlak model is a suitable approach for measuring low-level BBB permeability with low temporal resolution and high spatial resolution and brain coverage, and that normal levels of scanner instability would influence permeability measurements. DCE-MRI was performed in a cohort of mild stroke patients (n=201) with a range of cerebral small vessel disease severity. We fitted these data to a set of nested tracer kinetic models, ranking their performance according to the Akaike information criterion. To assess the influence of scanner drift, we scanned 15 healthy volunteers that underwent a "sham" DCE-MRI procedure without administration of contrast agent. Numerical simulations were performed to investigate model validity and the effect of scanner drift. The Patlak model was found to be most appropriate for fitting low-permeability data, and the simulations showed vp and K(Trans) estimates to be reasonably robust to the model assumptions. However, signal drift (measured at approximately 0.1% per minute and comparable to literature reports in other settings) led to systematic errors in calculated tracer kinetic parameters, particularly at low permeabilities. Our findings justify the growing use of the Patlak model in low-permeability

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Topical antihistamines display potent anti-inflammatory activity linked in part to enhanced permeability barrier function.

    Science.gov (United States)

    Lin, Tzu-Kai; Man, Mao-Qiang; Santiago, Juan-Luis; Park, Kyungho; Roelandt, Truus; Oda, Yuko; Hupe, Melanie; Crumrine, Debra; Lee, Hae-Jin; Gschwandtner, Maria; Thyssen, Jacob P; Trullas, Carles; Tschachler, Erwin; Feingold, Kenneth R; Elias, Peter M

    2013-02-01

    Systemic antagonists of the histamine type 1 and 2 receptors (H1/2r) are widely used as anti-pruritics and central sedatives, but demonstrate only modest anti-inflammatory activity. Because many inflammatory dermatoses result from defects in cutaneous barrier function, and because keratinocytes express both Hr1 and Hr2, we hypothesized that H1/2r antagonists might be more effective if they were used topically to treat inflammatory dermatoses. Topical H1/2r antagonists additively enhanced permeability barrier homeostasis in normal mouse skin by the following mechanisms: (i) stimulation of epidermal differentiation, leading to thickened cornified envelopes; and (ii) enhanced epidermal lipid synthesis and secretion. As barrier homeostasis was enhanced to a comparable extent in mast cell-deficient mice, with no further improvement following application of topical H1/2r antagonists, H1/2r antagonists likely oppose mast cell-derived histamines. In four immunologically diverse, murine disease models, characterized by either inflammation alone (acute irritant contact dermatitis, acute allergic contact dermatitis) or by prominent barrier abnormalities (subacute allergic contact dermatitis, atopic dermatitis), topical H1/2r agonists aggravated, whereas H1/2r antagonists improved, inflammation and/or barrier function. The apparent ability of topical H1r/2r antagonists to target epidermal H1/2r could translate into increased efficacy in the treatment of inflammatory dermatoses, likely due to decreased inflammation and enhanced barrier function. These results could shift current paradigms of antihistamine utilization from a predominantly systemic to a topical approach.

  12. NLRP3 protects alveolar barrier integrity by an inflammasome-independent increase of epithelial cell adherence.

    Science.gov (United States)

    Kostadinova, Elena; Chaput, Catherine; Gutbier, Birgitt; Lippmann, Juliane; Sander, Leif E; Mitchell, Timothy J; Suttorp, Norbert; Witzenrath, Martin; Opitz, Bastian

    2016-08-01

    Bacterial pneumonia is a major cause of acute lung injury and acute respiratory distress syndrome, characterized by alveolar barrier disruption. NLRP3 is best known for its ability to form inflammasomes and to regulate IL-1β and IL-18 production in myeloid cells. Here we show that NLRP3 protects the integrity of the alveolar barrier in a mouse model of Streptococcus pneumoniae-induced pneumonia, and ex vivo upon treatment of isolated perfused and ventilated lungs with the purified bacterial toxin, pneumolysin. We reveal that the preserving effect of NLRP3 on the lung barrier is independent of inflammasomes, IL-1β and IL-18. NLRP3 improves the integrity of alveolar epithelial cell monolayers by enhancing cellular adherence. Collectively, our study uncovers a novel function of NLRP3 by demonstrating that it protects epithelial barrier function independently of inflammasomes.

  13. Metabolic regulation of intestinal epithelial barrier during inflammation.

    Science.gov (United States)

    Colgan, Sean P; Curtis, Valerie F; Lanis, Jordi M; Glover, Louise E

    2015-01-01

    The gastrointestinal mucosa has proven to be an interesting tissue for which to investigate disease-related metabolism. In this review, we outline some evidence that implicates metabolic signaling as important features of barrier in the healthy and disease. Studies from cultured cell systems, animal models and human patients have revealed that metabolites generated within the inflammatory microenvironment are central to barrier regulation. These studies have revealed a prominent role for hypoxia and hypoxia-inducible factor (HIF) at key steps in adenine nucleotide metabolism and within the creatine kinase pathway. Results from animal models of intestinal inflammation have demonstrated an almost uniformly beneficial influence of HIF stabilization on disease outcomes and barrier function. Studies underway to elucidate the contribution of immune responses will provide additional insight into how metabolic changes contribute to the complexity of the gastrointestinal tract and how such information might be harnessed for therapeutic benefit.

  14. 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....

  15. Optimization Model for the Design of Multi-layered Permeable Reactive Barriers

    Science.gov (United States)

    Połoński, Mieczysław; Pawluk, Katarzyna; Rybka, Iwona

    2017-10-01

    Permeable reactive barriers (PRBs) are employed as in situ groundwater remediation technology. The installation of PRBs is usually a major investment, where one of the biggest cost drivers are material costs. PRBs are barriers against contaminants moving under the natural gradient, however not against groundwater contaminants. The most common construction of a PRB is a single barrier, but in the case of contaminant mixtures a multi-layered construction, i.e. a combination of different reactive materials and removal processes, is required. The most important parameters for PRB design are dimensions. The barrier must be long enough to treat the entire width of the plume (dimension perpendicular to groundwater flow) and should extend to and be keyed into an impermeable layer. The problem is to determine the optimal thickness of a PRB, which should provide a residence time appropriate for reducing the concentration of contaminants to the desired effluent concentration. In PRBs, design is accomplished using numerical methods or simulators, which are useful to predict the scenarios and evaluate the resulting groundwater flow systems to specific site conditions. On the other hand, numerical methods are complicated and may have significant errors if the discretization is too coarse or is incorrectly aligned. This paper deals with a simple, conceptual model of a one-approach optimization method for multi-layered PRB design. Based on literature and laboratory test results (residence time, density and hydraulic coefficient), a selection of layers of reactive materials was determined. Considering the lowest cost of the reactive materials, the required thicknesses of activated carbon, zeolite and zero valent iron were calculated using two different algorithms. The simple model may be used for preliminary barrier design and cost calculations. Using the optimization model in a preliminary design stage, it is possible to reject the PRB concept and avoid losing time for the

  16. Regulation of bronchial epithelial barrier integrity by type 2 cytokines and histone deacetylases in asthmatic patients.

    Science.gov (United States)

    Wawrzyniak, Paulina; Wawrzyniak, Marcin; Wanke, Kerstin; Sokolowska, Milena; Bendelja, Kreso; Rückert, Beate; Globinska, Anna; Jakiela, Bogdan; Kast, Jeannette I; Idzko, Marco; Akdis, Mübeccel; Sanak, Marek; Akdis, Cezmi A

    2017-01-01

    Tight junctions (TJs) form a barrier on the apical side of neighboring epithelial cells in the bronchial mucosa. Changes in their integrity might play a role in asthma pathogenesis by enabling the paracellular influx of allergens, toxins, and microbes to the submucosal tissue. The regulation of bronchial epithelial TJs by TH2 cells and their cytokines and their involvement in epigenetic regulation of barrier function were investigated. The expression, regulation, and function of TJs were determined in air-liquid interface (ALI) cultures of control and asthmatic primary human bronchial epithelial cells (HBECs) by means of analysis of transepithelial electrical resistance, paracellular flux, mRNA expression, Western blotting, and immunofluorescence staining. HBECs from asthmatic patients showed a significantly low TJ integrity in ALI cultures compared with HBECs from healthy subjects. TH2 cell numbers and levels of their cytokines, IL-4 and IL-13, decreased barrier integrity in ALI cultures of HBECs from control subjects but not in HBECs from asthmatic patients. They induced a physical separation of the TJs of adjacent cells in immunofluorescence staining of the TJ molecules occludin and zonula occludens-1. We observed that expression of histone deacetylases (HDACs) 1 and 9, and Silent information regulator genes (sirtuins [SIRTs]) 6 and 7 were significantly high in HBECs from asthmatic patients. IL-4 and IL-13 significantly increased the expression of HDACs and SIRTs. The role of HDAC activation on epithelial barrier leakiness was confirmed by HDAC inhibition, which improved barrier integrity through increased synthesis of TJ molecules in epithelium from asthmatic patients to the level seen in HBECs from control subjects. Our data demonstrate that barrier leakiness in asthmatic patients is induced by TH2 cells, IL-4, and IL-13 and HDAC activity. The inhibition of endogenous HDAC activity reconstitutes defective barrier by increasing TJ expression. Copyright © 2016

  17. 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.

  18. Loss of LSR affects epithelial barrier integrity and tumor xenograft growth of CaCo-2 cells.

    Science.gov (United States)

    Czulkies, Bernd A; Mastroianni, Justin; Lutz, Lisa; Lang, Sarah; Schwan, Carsten; Schmidt, Gudula; Lassmann, Silke; Zeiser, Robert; Aktories, Klaus; Papatheodorou, Panagiotis

    2017-06-06

    The lipolysis-stimulated lipoprotein receptor (LSR) is a lipoprotein receptor, serves as host receptor for clostridial iota-like toxins and is involved in the formation of tricellular contacts. Of particular interest is the role of LSR in progression of various cancers. Here we aimed to study the tumor growth of LSR-deficient colon carcinoma-derived cell lines HCT116 and CaCo-2 in a mouse xenograft model. Whereas knockout of LSR had no effect on tumor growth of HCT116 cells, we observed that CaCo-2 LSR knockout tumors grew to a smaller size than their wild-type counterparts. Histological analysis revealed increased apoptotic and necrotic cell death in a tumor originating from LSR-deficient CaCo-2 cells. LSR-deficient CaCo-2 cells exhibited increased cell proliferation in vitro and an altered epithelial morphology with impaired targeting of tricellulin to tricellular contacts. In addition, loss of LSR reduced the transepithelial electrical resistance of CaCo-2 cell monolayers and increased permeability for small molecules. Moreover, LSR-deficient CaCo-2 cells formed larger cysts in 3D culture than their wild-type counterparts. Our study provides evidence that LSR affects epithelial morphology and barrier formation in CaCo-2 cells and examines for the first time the effects of LSR deficiency on the tumor growth properties of colon carcinoma-derived cell lines.

  19. 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.......25 seconds) greatly improved accuracy and precision for all three models, enabling us to differentiate values of permeability as low as 0.1 ml/100 g/min from zero. The Patlak model yielded highest accuracy and precision for permeability values

  20. 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.

  1. 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.

  2. Hierarchical assembly of the eggshell and permeability barrier in C. elegans

    Science.gov (United States)

    Olson, Sara K.; Greenan, Garrett; Desai, Arshad; Müller-Reichert, Thomas

    2012-01-01

    In metazoans, fertilization triggers the assembly of an extracellular coat that constitutes the interface between the embryo and its environment. In nematodes, this coat is the eggshell, which provides mechanical rigidity, prevents polyspermy, and is impermeable to small molecules. Using immunoelectron microscopy, we found that the Caenorhabditis elegans eggshell was composed of an outer vitelline layer, a middle chitin layer, and an inner layer containing chondroitin proteoglycans. The switch between the chitin and proteoglycan layers was achieved by internalization of chitin synthase coincident with exocytosis of proteoglycan-containing cortical granules. Inner layer assembly did not make the zygote impermeable as previously proposed. Instead, correlative light and electron microscopy demonstrated that the permeability barrier was a distinct envelope that formed in a separate step that required fatty acid synthesis, the sugar-modifying enzyme PERM-1, and the acyl chain transfer enzyme DGTR-1. These findings delineate the hierarchy of eggshell assembly and define key molecular mechanisms at each step. PMID:22908315

  3. 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.

  4. Early CT perfusion changes and blood-brain barrier permeability after aneurysmal subarachnoid hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Amanda; Bharatha, Aditya [University of Toronto, Department of Medical Imaging, Toronto, ON (Canada); De Oliveira Manoel, Airton Leonardo; Kouzmina, Ekaterina [St. Michael' s Hospital, Toronto (Canada); Burgers, Kyle; Lee, Ting [Robarts Research Institute, London (Canada); Macdonald, R.L. [St. Michael' s Hospital, Department of Neurosurgery, Toronto (Canada)

    2015-08-15

    Early brain injury (EBI) can occur within 72 h of aneurysmal subarachnoid hemorrhage (aSAH). The objective of this study was to determine if there are differences in early CTP parameters (<72 h) with respect to delayed cerebral ischemia (DCI), cerebral infarction, and functional outcome. We performed a prospective cohort study of aSAH patients admitted to a single tertiary care center. MTT, CBF and blood-brain barrier permeability (PS) were quantified with CTP within 72 h of aneurysm rupture. Primary outcomes were functional outcome by the Modified Rankin Scale (mRS) at 3 months and cerebral infarction. Secondary outcome was the development of DCI. Differences between early CTP parameters were determined with respect to primary and secondary outcomes. Fifty aSAH patients were included in the final analysis. MTT was significantly higher in patients who developed DCI (6.7 ± 1.2 vs 5.9 ± 1.0; p = 0.03) and cerebral infarction (7.0 ± 1.2 vs 5.9 ± 0.9; p = 0.007); however, no difference in MTT was found between patients with and without a poor outcome (mRS > 2). Early CBF and PS did not differ with respect to functional outcome, DCI, and cerebral infarction. Elevated MTT within 72 h of aneurysm rupture is associated with DCI and cerebral infarction but not with long-term functional outcome. Blood-brain barrier permeability, as assessed by CT perfusion, was not associated with DCI or worse outcome in this cohort. (orig.)

  5. AN IN-SITU PERMEABLE REACTIVE BARRIER FOR THE TREATMENT OF HEXAVALENT CHROMIUM AND TRICHLOROETHYLENE IN GROUNDWATER: VOLUME 3 MULTICOMPONENT REACTIVE TRANSPORT MODELING

    Science.gov (United States)

    Reactive transport modeling has been conducted to describe the performance of the permeable reactive barrier at the Coast Guard Support Center near Elizabeth City, NC. The reactive barrier was installed to treat groundwater contaminated by hexavalent chromium and chlorinated org...

  6. 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.

  7. Antibiotic transport across bronchial epithelial cells: Effects of molecular weight, LogP and apparent permeability.

    Science.gov (United States)

    Stigliani, Mariateresa; Haghi, Mehra; Russo, Paola; Young, Paul M; Traini, Daniela

    2016-02-15

    The first step in developing a new inhalable formulation for the treatment of respiratory diseases is to understand the mechanisms involved in the absorption of drugs after lung deposition. This information could be important for the treatment of bacterial infection in the lung, where low permeability would probably be beneficial, or a systemic infection, where high permeability would be desirable. The goal of this study was to evaluate the transport of several antibiotics (ciprofloxacin, azithromycin, moxifloxacin, rifampicin, doxycycline and tobramycin) across human bronchial airway epithelium and to study the influence of molecular weight and LogP on the apparent permeability. The experiments were conducted using Calu-3 cells seeded in the apical compartment of 24-well Transwell® inserts. The antibiotics transport was measured in both apical to basolateral (A-B) and basolateral to apical (B-A) directions and the apparent permeability of each antibiotic was calculated. The A-B transport of ciprofloxacin and rifampicin was independent of the initial concentration in the donor compartment, suggesting the involvement of active transporters in their absorption. Moxifloxacin, doxycycline, azithromycin and tobramycin presented a low absorptive permeation in the A-B direction, indicating that these substances could be substrate for efflux pumps. Generally, all antibiotics studied showed low permeabilities in the B-A direction. These findings suggest that the inhalation route would be favorable for delivering these specific antibiotics for the treatment of respiratory infection, compared with present oral or intravenous administration. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. [Effect of infrasound on ultrastructure and permeability of rat's blood-retinal barrier].

    Science.gov (United States)

    Qiu, Ping; Zhang, Zuoming; Jiang, Yong; Gou, Qun; Wang, Bing; Gou, Lin; Chen, Jingzao

    2002-08-01

    To investigate the possible effect of infrasound on the ultra-structure and permeability of rat's blood-retinal barrier (BRB). Ultra-structural changes of BRB were observed through the injection of lanthanum nitrate (La), which was used as a tracer to demonstrate the breakdown of the BRB, into blood vessels. Fifteen mature male rats divided into 5 groups were exposed to infrasound at a 8 Hz frequency, 130 dB sound pressure level in a pressure chamber especially designed for the experiment for 0, 1, 7, 14, 21 days, respectively. Under the action of infrasound, along with the prolongation of exposure, the damage of BRB was severer and severer. On the 1st day, there was no significant change in La leakage. On the 7th day, La diffused in the interphotoreceptor space at nuclear level. On the 14th day, La granules could be seen in the space of nervous cells. Finally, on the 21st day, La was found between synapses, synapses and nerve cells, as well as between the nerve cells and supporting cells, then sometimes reached vitreous body. Under the electron microscope, there were no significant morphological changes, but changes related to metabolism, such as edematous mitochondria, dilated rough endoplasmic reticula, precipitation of glycogen grandules, widening of perinuclear space, etc. The results thus suggest that the exposure to infrasound cause the breakdown of rat's blood-retinal barrier and visual impairment.

  9. Effect of losartan on the blood-brain barrier permeability in diabetic hypertensive rats.

    Science.gov (United States)

    Kaya, M; Kalayci, R; Küçük, M; Arican, N; Elmas, I; Kudat, H; Korkut, F

    2003-11-07

    Our previous publication has stressed the benefits of losartan, an angiotensin II receptor blocker, on the permeability of blood-brain barrier (BBB) and blood pressure during L-NAME-induced hypertension. This study reports the impacts of anti-hypertensive treatment by losartan on the brain endothelial barrier function and the arterial blood pressure, during acute hypertension episode, in experimentally diabetic hypertensive rats. Systolic blood pressure measurements were taken with tail cuff method before and during administration of L-NAME (0.5 mg/ml). We induced diabetes by using alloxan (50 mg/kg, i.p). Losartan (3 mg/kg, i.v) was given to rats following the L-NAME treatment. Acute hypertensive vascular injury was induced by epinephrine (40 microg/kg). The BBB disruption was quantified according to the extravasation of the Evans blue (EB) dye. L-NAME induced a significant increase in arterial blood pressure on day 14 in normoglycemic and hyperglycemic rats (p hypertensive and diabetic hypertensive rats (p hypertension in diabetic hypertensive rats increased the content of EB dye dramatically in cerebellum and diencephalon (p cerebral cortex (p hypertensive rats treated with epinephrine (p hypertensive rats, epinephrine administration leads to an increase in microvascular-EB-albumin efflux to brain, however losartan treatment significantly attenuates this protein's transport to brain tissue.

  10. 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

    ). 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...... 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-mediated epithelial cell barrier protection from Salmonella invasion, thus encouraging future...

  11. LONG-TERM PERFORMANCE OF PERMEABLE REACTIVE BARRIERS USING ZERO-VALENT IRON: GEOCHEMICAL AND MICROBIOLOGICAL EFFECTS

    Science.gov (United States)

    Geochemical and microbiological factors that control long-term performance of subsurface permeable reactive barriers were evaluated at the Elizabeth City, NC and the Denver Federal Center, CO sites. These ground water treatment systems use zero-valent iron filings (Peerless Meta...

  12. Poloxamer bioadhesive hydrogel for buccal drug delivery: Cytotoxicity and trans-epithelial permeability evaluations using TR146 human buccal epithelial cell line.

    Science.gov (United States)

    Zeng, Ni; Mignet, Nathalie; Dumortier, Gilles; Olivier, Elodie; Seguin, Johanne; Maury, Marc; Scherman, Daniel; Rat, Patrice; Boudy, Vincent

    2015-11-30

    A salbutamol sulfate (SS)-Poloxamer bioadhesive hydrogel specially developed for buccal administration was investigated by studying interactions with TR146 human buccal epithelium cells (i.e. cellular toxicity (i) and trans-epithelial SS diffusion (ii)). The assessment of cell viability (MTT, Alamar Blue), membrane integrity (Neutral Red), and apoptosis assay (Hoechst 33342), were performed and associated to Digital Holographic Microscopy analysis. After the treatment of 2h, SS solution induced drastic cellular alterations that were prevented by hydrogels in relation with the concentrations of poloxamer and xanthan gum. The formulation containing P407 19%/P188 1%/Satiaxane 0.1% showed the best tolerance after single and multiple administrations and significantly reduced the trans-epithelial permeability from 5.00±0.29 (×10(3)) (SS solution) to 1.83±0.22 cm/h. Digital Holographic Microscopy images in good agreement with the viability data confirmed the great interest of this direct technique. In conclusion, the proposed hydrogels represent a safe and efficient buccal drug delivery platform. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Modeling immune functions of the mouse blood-cerebrospinal fluid barrier in vitro: primary rather than immortalized mouse choroid plexus epithelial cells are suited to study immune cell migration across this brain barrier.

    Science.gov (United States)

    Lazarevic, Ivana; Engelhardt, Britta

    2016-01-29

    The blood-cerebrospinal fluid barrier (BCSFB) established by the choroid plexus (CP) epithelium has been recognized as a potential entry site of immune cells into the central nervous system during immunosurveillance and neuroinflammation. The location of the choroid plexus impedes in vivo analysis of immune cell trafficking across the BCSFB. Thus, research on cellular and molecular mechanisms of immune cell migration across the BCSFB is largely limited to in vitro models. In addition to forming contact-inhibited epithelial monolayers that express adhesion molecules, the optimal in vitro model must establish a tight permeability barrier as this influences immune cell diapedesis. We compared cell line models of the mouse BCSFB derived from the Immortomouse(®) and the ECPC4 line to primary mouse choroid plexus epithelial cell (pmCPEC) cultures for their ability to establish differentiated and tight in vitro models of the BCSFB. We found that inducible cell line models established from the Immortomouse(®) or the ECPC4 tumor cell line did not express characteristic epithelial proteins such as cytokeratin and E-cadherin and failed to reproducibly establish contact-inhibited epithelial monolayers that formed a tight permeability barrier. In contrast, cultures of highly-purified pmCPECs expressed cytokeratin and displayed mature BCSFB characteristic junctional complexes as visualized by the junctional localization of E-cadherin, β-catenin and claudins-1, -2, -3 and -11. pmCPECs formed a tight barrier with low permeability and high electrical resistance. When grown in inverted filter cultures, pmCPECs were suitable to study T cell migration from the basolateral to the apical side of the BCSFB, thus correctly modelling in vivo migration of immune cells from the blood to the CSF. Our study excludes inducible and tumor cell line mouse models as suitable to study immune functions of the BCSFB in vitro. Rather, we introduce here an in vitro inverted filter model of the

  14. Effect of carbon nanoparticles on renal epithelial cell structure, barrier function, and protein expression.

    Science.gov (United States)

    Blazer-Yost, Bonnie L; Banga, Amiraj; Amos, Adam; Chernoff, Ellen; Lai, Xianyin; Li, Cheng; Mitra, Somenath; Witzmann, Frank A

    2011-09-01

    To assess effects of carbon nanoparticle (CNP) exposure on renal epithelial cells, fullerenes (C(60)), single-walled carbon nanotubes (SWNT), and multi-walled carbon nanotubes (MWNT) were incubated with a confluent renal epithelial line for 48 h. At low concentrations, CNP-treated cells exhibited significant decreases in transepithelial electrical resistance (TEER) but no changes in hormone-stimulated ion transport or CNP-induced toxicity or stress responses as measured by lactate dehydrogenase or cytokine release. The changes in TEER, manifested as an inverse relationship with CNP concentration, were mirrored by an inverse correlation between dose and changes in protein expression. Lower, more physiologically relevant, concentrations of CNP have the most profound effects on barrier cell function and protein expression. These results indicate an impact of CNPs on renal epithelial cells at concentrations lower than have been previously studied and suggest caution with regard to increasing CNP levels entering the food chain due to increasing environmental pollution.

  15. Impact of mineral fouling on hydraulic behavior of permeable reactive barriers.

    Science.gov (United States)

    Lin, Li; Benson, Craig H; Lawson, Elizabeth M

    2005-01-01

    This paper describes reactive transport simulations conducted to assess the impact of mineral fouling on the hydraulic behavior of continuous-wall permeable reactive barriers (PRBs) employing granular zero-valent iron (ZVI) in carbonate-rich alluvial aquifers. The reactive transport model included a geochemical algorithm for simulating corrosion and mineral precipitation reactions that have been observed in ZVI PRBs. Results of simulations show that porosity and hydraulic conductivity of the ZVI decrease over time and that flows are redistributed throughout the PRB in response to fouling of the pore space. Under typical conditions, only subtle changes occur within the first 10 years (i.e., duration of the current field experience record with PRBs), and the most significant changes do not occur until the PRB has operated for at least 30 years. However, changes can occur sooner (or later) if the rate at which mineral-forming ions are delivered to the PRB is higher (or lower) than that expected under typical conditions (i.e., due to higher/lower flow rate or inflowing ground water that has higher/lower ionic strength). When the PRB is more permeable than the aquifer, the median Darcy flux in the PRB does not change appreciably over time because the aquifer controls the rate of flow through the PRB. However, seepage velocities in the PRB increase, and residence times decrease, due to porosity reductions caused by accumulation of minerals in the pore space. When fouling becomes extensive, bypassing and reductions in flow rate in the PRB occur.

  16. 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.

  17. Promoting effect of lactoferrin on barrier function and epithelial differentiation of human keratinocytes.

    Science.gov (United States)

    Uchida, Ryo; Aoki, Reiji; Aoki-Yoshida, Ayako; Tajima, Atsushi; Takayama, Yoshiharu

    2017-02-01

    The purpose of this study was to elucidate the effects of bovine lactoferrin on keratinocyte differentiation and barrier function. Addition of bovine lactoferrin to differentiating HaCaT human keratinocytes led to increased transepithelial electrical resistance (TER), a marker of epithelial barrier function. This elevation was followed by upregulation of two differentiation markers, involucrin and filaggrin. The expression level of sterol regulatory element-binding protein-1 was also enhanced by bovine lactoferrin. The lactoferrin-induced upregulation of involucrin and filaggrin expression were confirmed in normal human epidermal keratinocytes (NHEK). Treatment with SB203580, a p38 mitogen-activated protein kinase (MAPK) α inhibitor, impaired the upregulation of involucrin and filaggrin expression in response to lactoferrin. The elevation of p38 MAPK phosphorylation was further enhanced by lactoferrin in the initial stage of differentiation of HaCaT keratinocytes. The findings suggest that bovine lactoferrin promotes epithelial differentiation by a p38-MAPK-dependent mechanism.

  18. Monitoring Performance of a Dual Wall Permeable Reactive Barrier for Treating Perchlorate and TCE

    Science.gov (United States)

    Dowman, C. E.; Hashimoto, Y.; Warner, S.; Bennett, P.; Gandhi, D.; Szerdy, F.; Neville, S.; Fennessy, C.; Scow, K. M.

    2008-12-01

    AMEC Geomatrix, through collaboration with Aerojet General Corporation and the University of California, Davis (UCD), has performed work leading to the installation of a dual wall permeable reactive barrier (PRB) system capable of treating perchlorate and chlorinated aliphatic hydrocarbon compounds (CAHs), including trichloroethylene (TCE), at Aerojet's Area 40 site in Sacramento, California. This unique system consisted of an upgradient zero-valent iron (ZVI) permeable reactive barrier (PRB) that is intended to not only degrade CAHs, but also, provide hydrogen generated from the ZVI corrosion process, to a downgradient bio-effective PRB (carbohydrate solution circulated through a gravel-packed trench) for destroying perchlorate. The subsurface was characterized during a site investigation, and numerous logistical and site-specific challenges of installation were addressed. The site-specific challenges included installation of a passive remediation system in a remote location with no access to electricity. The selected remediation system was keyed into the undulating bedrock 20 to 25 feet below the ground surface without the use of shoring. Under a collaborative effort, UCD provided initial bench testing. AMEC Geomatrix designed and installed the dual wall system consisting of two approximately parallel 50-foot long by 2-foot thick by 25-foot deep PRB segments which are separated by about 8 feet perpendicular to the approximate direction of groundwater flow. AMEC Geomatrix performed the installation of performance monitoring network, which consisted of 21 wells, and monitored these points for a 6-month period. Monitoring and sampling techniques were designed to measure water levels and water quality parameters in the subsurface during sampling events, to better assess the hydrologic and chemical processes. The monitoring results indicate that the upgradient ZVI PRB effectively treats groundwater with TCE concentrations approaching 60 mg/L, and in addition, may

  19. TLR2 mediates gap junctional intercellular communication through connexin-43 in intestinal epithelial barrier injury.

    Science.gov (United States)

    Ey, Birgit; Eyking, Annette; Gerken, Guido; Podolsky, Daniel K; Cario, Elke

    2009-08-14

    Gap junctional intercellular communication (GJIC) coordinates cellular functions essential for sustaining tissue homeostasis; yet its regulation in the intestine is not well understood. Here, we identify a novel physiological link between Toll-like receptor (TLR) 2 and GJIC through modulation of Connexin-43 (Cx43) during acute and chronic inflammatory injury of the intestinal epithelial cell (IEC) barrier. Data from in vitro studies reveal that TLR2 activation modulates Cx43 synthesis and increases GJIC via Cx43 during IEC injury. The ulcerative colitis-associated TLR2-R753Q mutant targets Cx43 for increased proteasomal degradation, impairing TLR2-mediated GJIC during intestinal epithelial wounding. In vivo studies using mucosal RNA interference show that TLR2-mediated mucosal healing depends functionally on intestinal epithelial Cx43 during acute inflammatory stress-induced damage. Mice deficient in TLR2 exhibit IEC-specific alterations in Cx43, whereas administration of a TLR2 agonist protects GJIC by blocking accumulation of Cx43 and its hyperphosphorylation at Ser368 to prevent spontaneous chronic colitis in MDR1alpha-deficient mice. Finally, adding the TLR2 agonist to three-dimensional intestinal mucosa-like cultures of human biopsies preserves intestinal epithelial Cx43 integrity and polarization ex vivo. In conclusion, Cx43 plays an important role in innate immune control of commensal-mediated intestinal epithelial wound repair.

  20. Signal Transduction Pathways Involved in Enterohemorrhagic Escherichia coli-Induced Alterations in T84 Epithelial Permeability

    OpenAIRE

    Philpott, Dana J.; McKay, Derek M.; Mak, Walter; Perdue, Mary H.; Sherman, Philip M.

    1998-01-01

    Enterohemorrhagic Escherichia coli (EHEC) infection is associated with watery diarrhea and can lead to complications, including hemorrhagic colitis and the hemolytic-uremic syndrome. The mechanisms by which these organisms produce diarrheal disease remain to be elucidated. Changes in T84 epithelial cell electrophysiology were examined following EHEC infection. T84 cell monolayers infected with EHEC O157:H7 displayed a time-dependent decrease in transepithelial resistance. Increases in the tra...

  1. Effects of ionizing radiation on the blood brain barrier permeability to pharmacologically active substances

    Energy Technology Data Exchange (ETDEWEB)

    Trnovec, T.; Kallay, Z.; Bezek, S. (Institute of Experimental Pharmacology, Bratislava (Yugoslavia))

    1990-12-01

    Ionizing radiation can impair the integrity of the blood brain barrier (BBB). Data on early and late damage after brain irradiation are usually reported separately, yet a gradual transition between these two types has become evident. Signs appearing within 3 weeks after irradiation are considered to be early manifestations. The mechanism of radiation-effected integrity impairment of the BBB is discussed in relation to changes in morphological structures forming the BBB, the endothelium of intracerebral vessels, and in the surrounding astrocytes. Alterations in the function of the BBB are manifested in the endothelium by changes in the ultrastructural location of the activity of phosphatases and by the activation of pinocytotic vesicular transport, and in astrocyte cytoplasm by glycogen deposition. The changes in ultrastructure were critically surveyed with regard to increasing doses of radiation to the brain in the range of 5 Gy to 960 Gy. The qualitative as well as the semiquantitative and quantitative observations on the passage of substances across the damaged BBB were treated separately. Qualitative changes are based mainly on findings of extravasation of vital stains and of labelled proteins. The quantitative studies established differences in radiation-induced changes in the permeability of the BBB depending on the structure and physico-chemical properties of the barrier penetrating tracers. Indirect evaluation of radiation-induced BBB changes is based on studies of pharmacological effects of substances acting on the CNS. In conclusion, radiation impairs significantly the integrity of the BBB following single irradiation of the brain with a dose exceeding 10-15 Gy. The response of the BBB to ionizing radiation is dependent both on the dose to which the brain is exposed and on specific properties of the tracer. 68 references.

  2. Permeable Reactive Barriers Designed To Mitigate Eutrophication Alter Bacterial Community Composition and Aquifer Redox Conditions

    Science.gov (United States)

    Hiller, Kenly A.; Foreman, Kenneth H.; Weisman, David

    2015-01-01

    Permeable reactive barriers (PRBs) consist of a labile carbon source that is positioned to intercept nitrate-laden groundwater to prevent eutrophication. Decomposition of carbon in the PRB drives groundwater anoxic, fostering microbial denitrification. Such PRBs are an ideal habitat to examine microbial community structure under high-nitrate, carbon-replete conditions in coastal aquifers. We examined a PRB installed at the Waquoit Bay National Estuarine Research Reserve in Falmouth, MA. Groundwater within and below the PRB was depleted in oxygen compared to groundwater at sites upgradient and at adjacent reference sites. Nitrate concentrations declined from a high of 25 μM upgradient and adjacent to the barrier to <0.1 μM within the PRB. We analyzed the total and active bacterial communities filtered from groundwater flowing through the PRB using amplicons of 16S rRNA and of the 16S rRNA genes. Analysis of the 16S rRNA genes collected from the PRB showed that the total bacterial community had high relative abundances of bacteria thought to have alternative metabolisms, such as fermentation, including candidate phyla OD1, OP3, TM7, and GN02. In contrast, the active bacteria had lower abundances of many of these bacteria, suggesting that the bacterial taxa that differentiate the PRB groundwater community were not actively growing. Among the environmental variables analyzed, dissolved oxygen concentration explained the largest proportion of total community structure. There was, however, no significant correlation between measured environmental parameters and the active microbial community, suggesting that controls on the active portion may differ from the community as a whole. PMID:26231655

  3. Evaluation of the increase in permeability of the blood-brain barrier during tumor progression after pulsed focused ultrasound.

    Science.gov (United States)

    Yang, Feng-Yi; Wang, Hsin-Ell; Lin, Guan-Liang; Lin, Hui-Hsien; Wong, Tai-Tong

    2012-01-01

    The purpose of this study was to evaluate the permeability of the blood-brain barrier after sonication by pulsed high-intensity focused ultrasound and to determine if such an approach increases the tumor:ipsilateral brain permeability ratio. F98 glioma-bearing Fischer 344 rats were injected intravenously with Evans blue with or without blood-tumor barrier disruption induced by transcranial pulsed high-intensity focused ultrasound. Sonication was applied at a frequency of 1 MHz with a 5% duty cycle and a repetition frequency of 1 Hz. The permeability of the blood-brain barrier was assessed by the extravasation of Evans blue. Contrast-enhanced magnetic resonance images were used to monitor the gadolinium deposition path associated with transcranial pulsed high-intensity focused ultrasound, and the influencing size and location was also investigated. In addition, whole brain histological analysis was performed. The results were compared by two-tailed unpaired t-test. The accumulation of Evans blue in brains and the tumor:ipsilateral brain permeability ratio of Evans blue were significantly increased after pulsed high-intensity focused ultrasound exposure. Evans blue injection followed by sonication showed an increase in the tumor:ipsilateral brain ratio of the target tumors (9.14:1) of about 2.23-fold compared with the control tumors (x4.09) on day 6 after tumor implantation. Magnetic resonance images showed that pulsed high-intensity focused ultrasound locally enhances the permeability of the blood-tumor barrier in the glioma-bearing rats. This method could allow enhanced synergistic effects with respect to other brain tumor treatment regimens.

  4. 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.

  5. Evaluation of five strategies to limit the impact of fouling in permeable reactive barriers.

    Science.gov (United States)

    Li, Lin; Benson, Craig H

    2010-09-15

    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. Copyright 2010 Elsevier B.V. All rights reserved.

  6. Investigating dominant processes in ZVI permeable reactive barriers using reactive transport modeling.

    Science.gov (United States)

    Weber, Anne; Ruhl, Aki S; Amos, Richard T

    2013-08-01

    The reactive and hydraulic efficacy of zero valent iron permeable reactive barriers (ZVI PRBs) is strongly affected by geochemical composition of the groundwater treated. An enhanced version of the geochemical simulation code MIN3P was applied to simulate dominating processes in chlorinated hydrocarbons (CHCs) treating ZVI PRBs including geochemical dependency of ZVI reactivity, gas phase formation and a basic formulation of degassing. Results of target oriented column experiments with distinct chemical conditions (carbonate, calcium, sulfate, CHCs) were simulated to parameterize the model. The simulations demonstrate the initial enhancement of anaerobic iron corrosion due to carbonate and long term inhibition by precipitates (chukanovite, siderite, iron sulfide). Calcium was shown to enhance long term corrosion due to competition for carbonate between siderite, chukanovite, and aragonite, with less inhibition of iron corrosion by the needle like aragonite crystals. Application of the parameterized model to a field site (Bernau, Germany) demonstrated that temporarily enhanced groundwater carbonate concentrations caused an increase in gas phase formation due to the acceleration of anaerobic iron corrosion. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Solid phase studies and geochemical modelling of low-cost permeable reactive barriers.

    Science.gov (United States)

    Bartzas, Georgios; Komnitsas, Kostas

    2010-11-15

    A continuous column experiment was carried out under dynamic flow conditions in order to study the efficiency of low-cost permeable reactive barriers (PRBs) to remove several inorganic contaminants from acidic solutions. A 50:50 w/w waste iron/sand mixture was used as candidate reactive media in order to activate precipitation and promote sorption and reduction-oxidation mechanisms. Solid phase studies of the exhausted reactive products after column shutdown, using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), confirmed that the principal Fe corrosion products identified in the reactive zone are amorphous iron (hydr)oxides (maghemite/magnetite and goethite), intermediate products (sulfate green rust), and amorphous metal sulfides such as amFeS and/or mackinawite. Geochemical modelling of the metal removal processes, including interactions between reactive media, heavy metal ions and sulfates, and interpretation of the ionic profiles was also carried out by using the speciation/mass transfer computer code PHREEQC-2 and the WATEQ4F database. Mineralogical characterization studies as well as geochemical modelling calculations also indicate that the effect of sulfate and silica sand on the efficiency of the reactive zone should be considered carefully during design and operation of low-cost field PRBs. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Erythropoietin protects the in vitro blood-brain barrier against VEGF-induced permeability.

    Science.gov (United States)

    Martínez-Estrada, Ofelia María; Rodríguez-Millán, Elisabeth; González-De Vicente, Esther; Reina, Manuel; Vilaró, Senén; Fabre, Myriam

    2003-11-01

    The blood-brain barrier (BBB) ensures the homeostasis of the brain microenvironment, mostly through complex tight junctions between brain endothelial cells that prevent the passage of hydrophilic molecules from blood to brain and vice versa. A recent study has shown in vivo that systemic administration of erythropoietin (Epo) protects against brain injury. Using an in vitro model of the bovine BBB, we observed that the expression of the Epo receptor is modulated by its ligand and hypoxic stimuli such as vascular endothelial growth factor (VEGF) treatment. In addition, Epo protects against the VEGF-induced permeability of the BBB, decreases the levels of endothelial nitric oxide synthase and restores junction proteins. The kinetic transport experiments revealed the capacity of Epo to cross the in vitro BBB in a saturable and specific way. Our results suggest a new mechanism for Epo-induced neuroprotection, in which circulating Epo controls and maintains the BBB through an Epo receptor signalling pathway and the re-establishment of cell junctions.

  9. Uranium precipitation in a permeable reactive barrier by progressive irreversible dissolution of zerovalent iron.

    Science.gov (United States)

    Morrison, S J; Metzler, D R; Carpenter, C E

    2001-01-15

    A permeable reactive barrier (PRB) containing zerovalent iron [Fe(O)] was installed at a former uranium milling site in Monticello, UT. A large-scale column experiment was conducted at the site to test the feasibility of Fe(O) to treat U prior to installing the PRB. Effluents from the field column experiment had pH values near 7.34, moderate decreases in C(IV) and Ca concentrations, and an elevated Fe concentration (27.1 mg/L). In contrast, groundwater exiting the PRB had a pH value of 9.82, decreases in C(IV) and Ca concentrations, and a low concentration of Fe (0.17 mg/L). A geochemical model was used to explain the chemical changes that occurred in both the field column experiment and the PRB. The model simulated the systems by the progressive irreversible dissolution of Fe(O). Modeling results indicated that a longer residence time in the PRB compared with the shorter residence time in the column contributed to the disparate effluent qualities. Prior to modeling, a controlled laboratory column experiment was conducted to help evaluate the dominant chemical mechanisms by which Fe(O) removes U from aqueous solutions. Results of the laboratory column experiment indicated that only a small amount of U could be adsorbed to ferric minerals, and, therefore, this mechanism was not considered in the model.

  10. Assessment of a Hydroxyapatite Permeable Reactive Barrier to Remediate Uranium at the Old Rifle Site Colorado.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert C.; Szecsody, James (PNNL); Rigali, Mark J.; Vermuel, Vince (PNNL); Leullen, Jon (AECOM)

    2016-02-01

    We have performed an initial evaluation and testing program to assess the effectiveness of a hydroxyapatite (Ca10(PO4)6(OH)2) permeable reactive barrier and source area treatment to decrease uranium mobility at the Department of Energy (DOE) former Old Rifle uranium mill processing site in Rifle, western Colorado. Uranium ore was processed at the site from the 1940s to the 1970s. The mill facilities at the site as well as the uranium mill tailings previously stored there have all been removed. Groundwater in the alluvial aquifer beneath the site still contains elevated concentrations of uranium, and is currently used for field tests to study uranium behavior in groundwater and investigate potential uranium remediation technologies. The technology investigated in this work is based on in situ formation of apatite in sediment to create a subsurface apatite PRB and also for source area treatment. The process is based on injecting a solution containing calcium citrate and sodium into the subsurface for constructing the PRB within the uranium plume. As the indigenous sediment micro-organisms biodegrade the injected citrate, the calcium is released and reacts with the phosphate to form hydroxyapatite (precipitate). This paper reports on proof-of-principle column tests with Old Rifle sediment and synthetic groundwater.

  11. Water permeability of Na+-K+-2C1- cotransporters in mammalian epithelial cells

    DEFF Research Database (Denmark)

    Hammann, Steffen; Herrera-Perez, J.J.; Bundgaard, Magnus

    2005-01-01

    . The anatomy of the cultured cell layer was investigated by light and electron microscopy. The transport rate of the cotransporter was determined from the bumetanide-sensitive component of 86Rb+ uptake, and volume changes were derived from quenching of the fluorescent dye calcein. The water permeability (Lp...... changes of the cotransporter and interaction with Na+, K+ and Cl-. Similar measurements were performed on immortalized cell cultures from the thick ascending limb of the loop of Henle (TALH). Given similar overall transport rates of bumetanide-sensitive 86Rb+, the NKCCs of this tissue did not contribute...

  12. Design, installation, and performance of a multi-layered permeable reactive barrier, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kaszuba, J. P. (John P.); Longmire, P. A. (Patrick A.); Strietelmeier, E. A. (Elizabeth A.); Taylor, T. P. (Tammy P.); Den-Baars, P. S. (Peter S.)

    2004-01-01

    A multi-layered permeable reactive barrier (PRB) has been installed in Mortandad Canyon, on the Pajarito Plateau in the north-central part of LANL, to demonstrate in-situ treatment of a suite of contaminants with dissimilar geochemical properties. The PRB will also mitigate possible vulnerabilities from downgradient contaminant movement within alluvial and deeper perched groundwater. Mortandad Canyon was selected as the location for this demonstration project because the flow of alluvial groundwater is constrained by the geology of the canyon, a large network of monitoring wells already were installed along the canyon reach, and the hydrochemistry and contaminant history of the canyon is well-documented. The PRB uses a funnel-and-gate system with a series of four reactive media cells to immobilize or destroy contaminants present in alluvial groundwater, including strontium-90, plutonium-238,239,240, americium-241, perchlorate, and nitrate. The four cells, ordered by sequence of contact with the groundwater, consist of gravel-sized scoria (for colloid removal); phosphate rock containing apatite (for metals and radionuclides); pecan shells and cotton seed admixed with gravel (bio-barrier, to deplete dissolved oxygen and destroy potential RCRA organic compounds, nitrate and perchlorate); and limestone (pH buffering and anion adsorption). Design elements of the PRB are based on laboratory-scale treatability studies and on a field investigation of hydrologic, geochemical, and geotechnical parameters. The PRB was designed with the following criteria: 1-day residence time within the biobarrier, 10-year lifetime, minimization of surface water infiltration and erosion, optimization of hydraulic capture, and minimization of excavated material requiring disposal. Each layer has been equipped with monitoring wells or ports to allow sampling of groundwater and reactive media, and monitor wells are located immediately adjacent to the up- and down-gradient perimeter of the

  13. Brain pericytes from stress-susceptible pigs increase blood-brain barrier permeability in vitro

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    Vandenhaute Elodie

    2012-06-01

    Full Text Available Abstract Background The function of pericytes remains questionable but with improved cultured technique and the use of genetically modified animals, it has become increasingly clear that pericytes are an integral part of blood–brain barrier (BBB function, and the involvement of pericyte dysfunction in certain cerebrovascular diseases is now emerging. The porcine stress syndrome (PSS is the only confirmed, homologous model of malignant hyperthermia (MH in veterinary medicine. Affected animals can experience upon slaughter a range of symptoms, including skeletal muscle rigidity, metabolic acidosis, tachycardia and fever, similar to the human syndrome. Symptoms are due to an enhanced calcium release from intracellular stores. These conditions are associated with a point mutation in ryr1/hal gene, encoding the ryanodine receptor, a calcium channel. Important blood vessel wall muscle modifications have been described in PSS, but potential brain vessel changes have never been documented in this syndrome. Methods In the present work, histological and ultrastructural analyses of brain capillaries from wild type and ryr1 mutated pigs were conducted to investigate the potential impairment of pericytes, in this pathology. In addition, brain pericytes were isolated from the three porcine genotypes (wild-type NN pigs; Nn and nn pigs, bearing one or two (n mutant ryr1/hal alleles, respectively, and tested in vitro for their influence on the permeability of BBB endothelial monolayers. Results Enlarged perivascular spaces were observed in ryr1-mutant samples, corresponding to a partial or total detachment of the astrocytic endfeet. These spaces were electron lucent and sometimes filled with lipid deposits and swollen astrocytic feet. At the ultrastructural level, brain pericytes did not seem to be affected because they showed regular morphology and characteristics, so we aimed to check their ability to maintain BBB properties in vitro. Our results indicated

  14. Reinforcement of intestinal epithelial barrier by arabinoxylans in overweight and obese subjects: A randomized controlled trial: Arabinoxylans in gut barrier.

    Science.gov (United States)

    Salden, Bouke N; Troost, Freddy J; Wilms, Ellen; Truchado, Pilar; Vilchez-Vargas, Ramiro; Pieper, Dietmar H; Jáuregui, Ruy; Marzorati, Massimo; van de Wiele, Tom; Possemiers, Sam; Masclee, Ad A

    2017-02-03

    Obesity and metabolic diseases are associated with alterations in microbial composition and impaired gut barrier. Previous in vitro and animal studies have shown that arabinoxylans (AX) have the potential to modulate gut microbiota and gut barrier and therefore could have a protective role. Primary aim of the study was to investigate the effect of AX on intestinal permeability. Secondary aims included the effect of AX on gene transcription and protein expression of tight junctions (TJ), intestinal microbiota composition and activity, immune response and metabolic markers in overweight and obese individuals. In this randomized, double-blind, placebo-controlled trial, 47 overweight subjects were randomly assigned to groups receiving 7.5 g/d AX (n = 16), 15 g/d AX (n = 17) or 15 g/d placebo (n = 14) for 6 wks. Intestinal permeability was investigated using a multi-sugar test. Sigmoid colon tissue was obtained from a subgroup (n = 26) for analyzing gene transcription and mucosal expression of TJ proteins. Fecal samples were collected to assess microbial composition and activity. Furthermore, the production of cytokines by stimulated peripheral blood mononuclear cells (PBMCs) was examined. Blood was also sampled for measuring metabolic markers. No significant changes in gastrointestinal permeability and TJ protein expression were observed after 6 wks AX supplementation compared to placebo. However, gene transcription of occludin was upregulated in the 7.5 g AX group, and transcription of claudin-3 and claudin-4 were upregulated in the 15 g AX group compared to placebo. Furthermore, fecal microbiota diversity was decreased after 6 wks 15 g AX treatment, but no change in relative abundance of dominant phyla was observed. AX intake significantly decreased fecal pH and increased fecal concentrations of total SCFAs, acetate, propionate and butyrate, compared to placebo. Additionally, a decreased TNFα production by stimulated PBMCs was observed after 15

  15. Bifidobacteria Prevent Tunicamycin-Induced Endoplasmic Reticulum Stress and Subsequent Barrier Disruption in Human Intestinal Epithelial Caco-2 Monolayers.

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    Takuya Akiyama

    Full Text Available Endoplasmic reticulum (ER stress is caused by accumulation of unfolded and misfolded proteins in the ER, thereby compromising its vital cellular functions in protein production and secretion. Genome wide association studies in humans as well as experimental animal models linked ER stress in intestinal epithelial cells (IECs with intestinal disorders including inflammatory bowel diseases. However, the mechanisms linking the outcomes of ER stress in IECs to intestinal disease have not been clarified. In this study, we investigated the impact of ER stress on intestinal epithelial barrier function using human colon carcinoma-derived Caco-2 monolayers. Tunicamycin-induced ER stress decreased the trans-epithelial electrical resistance of Caco-2 monolayers, concomitant with loss of cellular plasma membrane integrity. Epithelial barrier disruption in Caco-2 cells after ER stress was not caused by caspase- or RIPK1-dependent cell death but was accompanied by lysosomal rupture and up-regulation of the ER stress markers Grp78, sXBP1 and Chop. Interestingly, several bifidobacteria species inhibited tunicamycin-induced ER stress and thereby diminished barrier disruption in Caco-2 monolayers. Together, these results showed that ER stress compromises the epithelial barrier function of Caco-2 monolayers and demonstrate beneficial impacts of bifidobacteria on ER stress in IECs. Our results identify epithelial barrier loss as a potential link between ER stress and intestinal disease development, and suggest that bifidobacteria could exert beneficial effects on this phenomenon.

  16. Bifidobacteria Prevent Tunicamycin-Induced Endoplasmic Reticulum Stress and Subsequent Barrier Disruption in Human Intestinal Epithelial Caco-2 Monolayers.

    Science.gov (United States)

    Akiyama, Takuya; Oishi, Kenji; Wullaert, Andy

    2016-01-01

    Endoplasmic reticulum (ER) stress is caused by accumulation of unfolded and misfolded proteins in the ER, thereby compromising its vital cellular functions in protein production and secretion. Genome wide association studies in humans as well as experimental animal models linked ER stress in intestinal epithelial cells (IECs) with intestinal disorders including inflammatory bowel diseases. However, the mechanisms linking the outcomes of ER stress in IECs to intestinal disease have not been clarified. In this study, we investigated the impact of ER stress on intestinal epithelial barrier function using human colon carcinoma-derived Caco-2 monolayers. Tunicamycin-induced ER stress decreased the trans-epithelial electrical resistance of Caco-2 monolayers, concomitant with loss of cellular plasma membrane integrity. Epithelial barrier disruption in Caco-2 cells after ER stress was not caused by caspase- or RIPK1-dependent cell death but was accompanied by lysosomal rupture and up-regulation of the ER stress markers Grp78, sXBP1 and Chop. Interestingly, several bifidobacteria species inhibited tunicamycin-induced ER stress and thereby diminished barrier disruption in Caco-2 monolayers. Together, these results showed that ER stress compromises the epithelial barrier function of Caco-2 monolayers and demonstrate beneficial impacts of bifidobacteria on ER stress in IECs. Our results identify epithelial barrier loss as a potential link between ER stress and intestinal disease development, and suggest that bifidobacteria could exert beneficial effects on this phenomenon.

  17. Reactive Transport Modeling for Mobilization of Arsenic in a Sediment Downgradient from an Iron Permeable Reactive Barrier

    OpenAIRE

    Sung-Wook Jeen

    2017-01-01

    Arsenic (As) can be naturally present in the native aquifer materials and can be released to groundwater through reduction dissolution of iron oxides containing As. While granular iron permeable reactive barriers (PRBs) can be effective for the treatment of arsenic in groundwater, the mobilization of arsenic in the sediment downgradient of the PRB might be an issue due to the reduced geochemical conditions generated by reactions in the PRB. The release of arsenic in the sediment downgradient ...

  18. Modeling porosity reductions caused by mineral fouling in continuous-wall permeable reactive barriers.

    Science.gov (United States)

    Li, Lin; Benson, Craig H; Lawson, Elizabeth M

    2006-02-01

    A study was conducted to assess key factors to include when modeling porosity reductions caused by mineral fouling in permeable reactive barriers (PRBs) containing granular zero valent iron. The public domain codes MODFLOW and RT3D were used and a geochemical algorithm was developed for RT3D to simulate geochemical reactions occurring in PRBs. Results of simulations conducted with the model show that the largest porosity reductions occur between the entrance and mid-plane of the PRB as a result of precipitation of carbonate minerals and that smaller porosity reductions occur between the mid-plane and exit face due to precipitation of ferrous hydroxide. These findings are consistent with field and laboratory observations, as well as modeling predictions made by others. Parametric studies were conducted to identify the most important variables to include in a model evaluating porosity reduction. These studies showed that three minerals (CaCO3, FeCO3, and Fe(OH)2 (am)) account for more than 99% of the porosity reductions that were predicted. The porosity reduction is sensitive to influent concentrations of HCO3-, Ca2+, CO3(2-), and dissolved oxygen, the anaerobic iron corrosion rate, and the rates of CaCO3 and FeCO3 formation. The predictions also show that porosity reductions in PRBs can be spatially variable and mineral forming ions penetrate deeper into the PRB as a result of flow heterogeneities, which reflects the balance between the rate of mass transport and geochemical reaction rates. Level of aquifer heterogeneity and the contrast in hydraulic conductivity between the aquifer and PRB are the most important hydraulic variables affecting porosity reduction. Spatial continuity of aquifer hydraulic conductivity is less significant.

  19. Checkpoint Kinase 1 Activation Enhances Intestinal Epithelial Barrier Function via Regulation of Claudin-5 Expression.

    Directory of Open Access Journals (Sweden)

    Akihiro Watari

    Full Text Available Several stressors are known to influence epithelial tight junction (TJ integrity, but the association between DNA damage and TJ integrity remains unclear. Here we examined the effects of daunorubicin and rebeccamycin, two anti-tumor chemicals that induce DNA damage, on TJ integrity in human intestinal epithelial cells. Daunorubicin and rebeccamycin dose-dependently enhanced transepithelial electrical resistance (TER and decreased flux of the 4 kDa FITC-dextran in Caco-2 cell monolayer. Daunorubicin- or rebeccamycin-induced enhancement of the TJ barrier function partly rescued attenuation of the barrier function by the inflammatory cytokines TNF-α and IFN-γ. Daunorubicin and rebeccamycin increased claudin-5 expression and the product was distributed in the actin cytoskeleton fraction, which was enriched with TJ proteins. Caffeine, which is an inhibitor of ataxia telangiectasia mutated protein (ATM and ataxia telangiectasia mutated and Rad3-related protein (ATR, and the Chk1 inhibitor inhibited the TER increases induced by daunorubicin and rebeccamycin, whereas a Chk2 inhibitor did not. Treatment with Chk1 siRNA also significantly inhibited the TER increases. Induction of claudin-5 expression was inhibited by Chk1 inhibitor and by siRNA treatment. Our results suggest that Chk1 activation by daunorubicin and rebeccamycin induced claudin-5 expression and enhanced TJ barrier function in Caco-2 cell monolayer, which suggests a link between DNA damage and TJ integrity in the human intestine.

  20. 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.

  1. A metalloproteinase secreted by Streptococcus pneumoniae removes membrane mucin MUC16 from the epithelial glycocalyx barrier.

    Directory of Open Access Journals (Sweden)

    Bharathi Govindarajan

    Full Text Available The majority of bacterial infections occur across wet-surfaced mucosal epithelia, including those that cover the eye, respiratory tract, gastrointestinal tract and genitourinary tract. The apical surface of all these mucosal epithelia is covered by a heavily glycosylated glycocalyx, a major component of which are membrane-associated mucins (MAMs. MAMs form a barrier that serves as one of the first lines of defense against invading bacteria. While opportunistic bacteria rely on pre-existing defects or wounds to gain entry to epithelia, non opportunistic bacteria, especially the epidemic disease-causing ones, gain access to epithelial cells without evidence of predisposing injury. The molecular mechanisms employed by these non opportunistic pathogens to breach the MAM barrier remain unknown. To test the hypothesis that disease-causing non opportunistic bacteria gain access to the epithelium by removal of MAMs, corneal, conjunctival, and tracheobronchial epithelial cells, cultured to differentiate to express the MAMs, MUCs 1, 4, and 16, were exposed to a non encapsulated, non typeable strain of Streptococcus pneumoniae (SP168, which causes epidemic conjunctivitis. The ability of strain SP168 to induce MAM ectodomain release from epithelia was compared to that of other strains of S. pneumoniae, as well as the opportunistic pathogen Staphylococcus aureus. The experiments reported herein demonstrate that the epidemic disease-causing S. pneumoniae species secretes a metalloproteinase, ZmpC, which selectively induces ectodomain shedding of the MAM MUC16. Furthermore, ZmpC-induced removal of MUC16 from the epithelium leads to loss of the glycocalyx barrier function and enhanced internalization of the bacterium. These data suggest that removal of MAMs by bacterial enzymes may be an important virulence mechanism employed by disease-causing non opportunistic bacteria to gain access to epithelial cells to cause infection.

  2. Protective effects of nonionic tri-block copolymers on bile acid-mediated epithelial barrier disruption.

    Energy Technology Data Exchange (ETDEWEB)

    Edelstein, A.; Fink, D.; Musch, M.; Valuckaite, V.; Zabornia, O.; Grubjesic, S.; Firestone, M. A.; Matthews, J. B.; Alverdy, J. C. (Materials Science Division); (Univ. of Chicago)

    2011-11-01

    Translocation of bacteria and other luminal factors from the intestine following surgical injury can be a major driver of critical illness. Bile acids have been shown to play a key role in the loss of intestinal epithelial barrier function during states of host stress. Experiments to study the ability of nonionic block copolymers to abrogate barrier failure in response to bile acid exposure are described. In vitro experiments were performed with the bile salt sodium deoxycholate on Caco-2 enterocyte monolayers using transepithelial electrical resistance to assay barrier function. A bisphenol A coupled triblock polyethylene glycol (PEG), PEG 15-20, was shown to prevent sodium deoxycholate-induced barrier failure. Enzyme-linked immunosorbent assay, lactate dehydrogenase, and caspase 3-based cell death detection assays demonstrated that bile acid-induced apoptosis and necrosis were prevented with PEG 15-20. Immunofluorescence microscopic visualization of the tight junctional protein zonula occludens 1 (ZO-1) demonstrated that PEG 15-20 prevented significant changes in tight junction organization induced by bile acid exposure. Preliminary transepithelial electrical resistance-based studies examining structure-function correlates of polymer protection against bile acid damage were performed with a small library of PEG-based copolymers. Polymer properties associated with optimal protection against bile acid-induced barrier disruption were PEG-based compounds with a molecular weight greater than 10 kd and amphiphilicity. The data demonstrate that PEG-based copolymer architecture is an important determinant that confers protection against bile acid injury of intestinal epithelia.

  3. Enterohemorrhagic E. coli alters murine intestinal epithelial tight junction protein expression and barrier function in Shiga toxin independent manner

    Science.gov (United States)

    Roxas, Jennifer Lising; Koutsouris, Athanasia; Bellmeyer, Amy; Tesfay, Samuel; Royan, Sandhya; Falzari, Kanakeshwari; Harris, Antoneicka; Cheng, Hao; Rhee, Ki-Jong; Hecht, Gail

    2010-01-01

    Shiga toxin (Stx) is implicated in the development of hemorrhagic colitis and hemolytic-uremic syndrome, but early symptoms of enterohemorrhagic Escherichia coli (EHEC) infection such as non-bloody diarrhea may be Stx-independent. In this study, we defined the effects of EHEC, in the absence of Stx, on the intestinal epithelium using a murine model. EHEC colonization of intestines from two groups of antibiotic-free and streptomycin-treated C57Bl/6J mice were characterized and compared. EHEC colonized the cecum and colon more efficiently than the ileum in both groups; however, greater amounts of tissue-associated EHEC were detected in streptomycin-pretreated mice. Imaging of intestinal tissues of mice infected with bioluminescent EHEC further confirmed tight association of the bacteria to the cecum and colon. Greater numbers of EHEC were also cultured from stool of streptomycin-pretreated mice, as compared to those that received no antibiotic. Transmission electron microscopy demonstrated that EHEC infection leads to microvillous effacement of mouse colonocytes. Hematoxylin and eosin staining of colonic tissues of infected mice revealed a slight increase in the number of lamina propria polymorphonuclear leukocytes. Transmucosal electrical resistance, a measure of epithelial barrier function, was reduced in colonic tissues of infected animals. Increased mucosal permeability to 4KDa FITC-Dextran was also observed in colonic tissues of infected mice. Immunofluorescence microscopy revealed that EHEC infection resulted in redistribution of the tight junction proteins occludin and claudin-3 and increased expression of claudin-2 while ZO-1 localization remained unaltered. Quantitative real-time PCR revealed that EHEC altered mRNA transcription of Ocln, Cldn2 and Cldn3. Most notably, claudin-2 expression was significantly increased and correlated with increased intestinal permeability. Our data indicate that C57Bl/6J mice serve as an in vivo model to study the physiological

  4. Enterohemorrhagic E. coli alters murine intestinal epithelial tight junction protein expression and barrier function in a Shiga toxin independent manner.

    Science.gov (United States)

    Roxas, Jennifer L; Koutsouris, Athanasia; Bellmeyer, Amy; Tesfay, Samuel; Royan, Sandhya; Falzari, Kanakeshwari; Harris, Antoneicka; Cheng, Hao; Rhee, Ki Jong; Hecht, Gail

    2010-08-01

    Shiga toxin (Stx) is implicated in the development of hemorrhagic colitis and hemolytic-uremic syndrome, but early symptoms of enterohemorrhagic Escherichia coli (EHEC) infection such as nonbloody diarrhea may be Stx independent. In this study, we defined the effects of EHEC, in the absence of Stx, on the intestinal epithelium using a murine model. EHEC colonization of intestines from two groups of antibiotic-free and streptomycin-treated C57Bl/6J mice were characterized and compared. EHEC colonized the cecum and colon more efficiently than the ileum in both groups; however, greater amounts of tissue-associated EHEC were detected in streptomycin-pretreated mice. Imaging of intestinal tissues of mice infected with bioluminescent EHEC further confirmed tight association of the bacteria with the cecum and colon. Greater numbers of EHEC were also cultured from stool samples obtained from streptomycin-pretreated mice, as compared with those that received no antibiotics. Transmission electron microscopy shows that EHEC infection leads to microvillous effacement of mouse colonocytes. Hematoxylin and eosin staining of the colonic tissues of infected mice revealed a slight increase in the number of lamina propria polymorphonuclear leukocytes. Transmucosal electrical resistance, a measure of epithelial barrier function, was reduced in the colonic tissues of infected animals. Increased mucosal permeability to 4- kDa FITC-dextran was also observed in the colonic tissues of infected mice. Immunofluorescence microscopy showed that EHEC infection resulted in redistribution of the tight junction (TJ) proteins occludin and claudin-3 and increased the expression of claudin-2, whereas ZO-1 localization remained unaltered. Quantitative real-time PCR showed that EHEC altered mRNA transcription of OCLN, CLDN2, and CLDN3. Most notably, claudin-2 expression was significantly increased and correlated with increased intestinal permeability. Our data indicate that C57Bl/6J mice serve as an

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

    Energy Technology Data Exchange (ETDEWEB)

    Korte, NE

    2001-06-11

    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. A review of the literature reveals that cautions regarding subsurface heterogeneity were published several years prior to the full-scale implementations. Nevertheless, design and construction have typically been undertaken as if the subsurface was homogeneous. More recently published literature has demonstrated that hydraulic heterogeneity can cause so much uncertainty in performance that use of a passive PRB is precluded. Thus, the primary conclusion of this review is that more attention must be given to site-specific issues. Indeed, the use of a passive PRB requires

  6. Cardiotoxic drugs Herceptin and doxorubicin inhibit cardiac microvascular endothelial cell barrier formation resulting in increased drug permeability

    Directory of Open Access Journals (Sweden)

    Emma L. Wilkinson

    2016-10-01

    Full Text Available Cardiotoxicity induced by anti-cancer therapeutics is a severe, and potentially fatal, adverse reaction of the heart in response to certain drugs. Current in vitro approaches to assess cardiotoxicity have focused on analysing cardiomyocytes. More recently it has become apparent that non-cardiomyocyte cells of the heart can potentially contribute to cardiotoxicity. Herceptin and doxorubicin are known to induce cardiotoxicity in the clinic. The effect of these drugs on the endothelial tight junction barrier was tested by analysing tight junction formation and zona occludens-1 (ZO-1 levels, revealing that Herceptin and doxorubicin are able to induce barrier perturbment and decrease barrier function in human cardiac microvascular endothelial cells (HCMECs leading to increased permeability. Herceptin treatment had no effect on the tight junction barrier function in human dermal and human brain microvascular endothelial cells. HCMECs showed detectable levels of HER2 compared with the other endothelial cells suggesting that Herceptin binding to HER2 in these cells may interfere with tight junction formation. Our data suggests that doxorubicin and Herceptin can affect tight junction formation in the cardiac microvasculature leading to increased drug permeability and adverse effects on the cardiac myocytes.

  7. Bacterial translocation and in vivo assessment of intestinal barrier permeability in Rainbow trout (Oncorhynchus mykiss) with and without soyabean meal-induced inflammation

    NARCIS (Netherlands)

    Mosberian Tanha, Peyman; Overland, M.; Landsverk, Thor; Reveco, Felipe E.; Schrama, J.W.; Roem, A.J.; Agger, Jane W.; Midland, Liv T.

    2016-01-01

    The primary aim of this experiment was to evaluate the intestinal barrier permeability in vivo in rainbow trout (Oncorhynchus mykiss) fed increasing levels of soyabean meal (SBM). The relationship between SBM-induced enteritis (SBMIE) and the permeability markers was also investigated. Our results

  8. Adult human dental pulp stem cells promote blood-brain barrier permeability through vascular endothelial growth factor-a expression.

    Science.gov (United States)

    Winderlich, Joshua N; Kremer, Karlea L; Koblar, Simon A

    2016-06-01

    Stem cell therapy is a promising new treatment option for stroke. Intravascular administration of stem cells is a valid approach as stem cells have been shown to transmigrate the blood-brain barrier. The mechanism that causes this effect has not yet been elucidated. We hypothesized that stem cells would mediate localized discontinuities in the blood-brain barrier, which would allow passage into the brain parenchyma. Here, we demonstrate that adult human dental pulp stem cells express a soluble factor that increases permeability across an in vitro model of the blood-brain barrier. This effect was shown to be the result of vascular endothelial growth factor-a. The effect could be amplified by exposing dental pulp stem cell to stromal-derived factor 1, which stimulates vascular endothelial growth factor-a expression. These findings support the use of dental pulp stem cell in therapy for stroke. © The Author(s) 2015.

  9. Entamoeba histolytica contains an occludin-like protein that can alter colonic epithelial barrier function.

    Directory of Open Access Journals (Sweden)

    Michael Goplen

    Full Text Available The exact mechanism by which Entamoeba histolytica disrupts the human colonic epithelium and invades the mucosa has yet to be clearly elucidated. E. histolytica produces a diverse array of putative virulent factors such as glycosidase, cysteine proteinases and amebapore that can modulate and/or disrupt epithelial barrier functions. However, it is currently thought that E. histolytica produces numerous other molecules and strategies to disrupt colonic mucosal defenses. In this study, we document a putative mechanism whereby the parasite alters the integrity of human epithelium by expressing a cognate tight junction protein of the host. We detected this protein as "occludin-like" as revealed by immunoblotting and immunoprecipitation studies and visualization by confocal microscopy using antibodies highly specific for human occludin. We propose that E. histolytica occludin-like protein might displace mucosal epithelial occludin-occludin tight junction interactions resulting in epithelial disruption analogous to sub mucosal human dendritic cells sampling luminal contents. These results indicate that E. histolytica occludin is a putative virulent component that can play a role in the pathogenesis of intestinal amebiasis.

  10. Breakdown of Epithelial Barrier Integrity and Overdrive Activation of Alveolar Epithelial Cells in the Pathogenesis of Acute Respiratory Distress Syndrome and Lung Fibrosis

    Directory of Open Access Journals (Sweden)

    Shigehisa Yanagi

    2015-01-01

    Full Text Available Individual alveolar epithelial cells (AECs collaboratively form a tight barrier between atmosphere and fluid-filled tissue to enable normal gas exchange. The tight junctions of AECs provide intercellular sealing and are integral to the maintenance of the AEC barrier integrity. Disruption and failure of reconstitution of AEC barrier result in catastrophic consequences, leading to alveolar flooding and subsequent devastating fibrotic scarring. Recent evidences reveal that many of the fibrotic lung diseases involve AECs both as a frequent target of injury and as a driver of ongoing pathological processes. Aberrantly activated AECs express most of the growth factors and chemokines responsible for the proliferation, migration, and activation of fibroblasts. Current evidences suggest that AECs may acquire overdrive activation in the initial step of fibrosis by several mechanisms, including abnormal recapitulation of the developmental pathway, defects of the molecules essential for epithelial integrity, and acceleration of aging-related properties. Among these initial triggering events, epithelial Pten, a multiple phosphatase that negatively regulates the PI3K/Akt pathway and is crucial for lung development, is essential for the prevention of alveolar flooding and lung fibrosis through the regulation of AEC barrier integrity after injury. Reestablishment of AEC barrier integrity also involves the deployment of specialized stem/progenitor cells.

  11. Overview on backfill materials and permeable reactive barriers for nuclear waste disposal facilities.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Hasan, Ahmed Ali Mohamed; Holt, Kathleen Caroline; Hasan, Mahmoud A. (Egyptian Atomic Energy Authority, Cairo, Egypt)

    2003-10-01

    A great deal of money and effort has been spent on environmental restoration during the past several decades. Significant progress has been made on improving air quality, cleaning up and preventing leaching from dumps and landfills, and improving surface water quality. However, significant challenges still exist in all of these areas. Among the more difficult and expensive environmental problems, and often the primary factor limiting closure of contaminated sites following surface restoration, is contamination of ground water. The most common technology used for remediating ground water is surface treatment where the water is pumped to the surface, treated and pumped back into the ground or released at a nearby river or lake. Although still useful for certain remediation scenarios, the limitations of pump-and-treat technologies have recently been recognized, along with the need for innovative solutions to ground-water contamination. Even with the current challenges we face there is a strong need to create geological repository systems for dispose of radioactive wastes containing long-lived radionuclides. The potential contamination of groundwater is a major factor in selection of a radioactive waste disposal site, design of the facility, future scenarios such as human intrusion into the repository and possible need for retrieving the radioactive material, and the use of backfills designed to keep the radionuclides immobile. One of the most promising technologies for remediation of contaminated sites and design of radioactive waste repositories is the use of permeable reactive barriers (PRBs). PRBs are constructed of reactive material(s) to intercept and remove the radionuclides from the water and decontaminate the plumes in situ. The concept of PRBs is relatively simple. The reactive material(s) is placed in the subsurface between the waste or contaminated area and the groundwater. Reactive materials used thus far in practice and research include zero valent iron

  12. Qualitative and quantitative structure-activity relationship modelling for predicting blood-brain barrier permeability of structurally diverse chemicals.

    Science.gov (United States)

    Gupta, S; Basant, N; Singh, K P

    2015-01-01

    In this study, structure-activity relationship (SAR) models have been established for qualitative and quantitative prediction of the blood-brain barrier (BBB) permeability of chemicals. The structural diversity of the chemicals and nonlinear structure in the data were tested. The predictive and generalization ability of the developed SAR models were tested through internal and external validation procedures. In complete data, the QSAR models rendered ternary classification accuracy of >98.15%, while the quantitative SAR models yielded correlation (r(2)) of >0.926 between the measured and the predicted BBB permeability values with the mean squared error (MSE) 82.7% and r(2) > 0.905 (MSE quantitative models for predicting the BBB permeability of chemicals. Moreover, these models showed predictive performance superior to those reported earlier in the literature. This demonstrates the appropriateness of the developed SAR models to reliably predict the BBB permeability of new chemicals, which can be used for initial screening of the molecules in the drug development process.

  13. The P2Y6 receptor mediates Clostridium difficile toxin-induced CXCL8/IL-8 production and intestinal epithelial barrier dysfunction.

    Directory of Open Access Journals (Sweden)

    Ashleigh Hansen

    Full Text Available C. difficile is a Gram-positive spore-forming anaerobic bacterium that is the leading cause of nosocomial diarrhea in the developed world. The pathogenesis of C. difficile infections (CDI is driven by toxin A (TcdA and toxin B (TcdB, secreted factors that trigger the release of inflammatory mediators and contribute to disruption of the intestinal epithelial barrier. Neutrophils play a key role in the inflammatory response and the induction of pseudomembranous colitis in CDI. TcdA and TcdB alter cytoskeletal signaling and trigger the release of CXCL8/IL-8, a potent neutrophil chemoattractant, from intestinal epithelial cells; however, little is known about the surface receptor(s that mediate these events. In the current study, we sought to assess whether toxin-induced CXCL8/IL-8 release and barrier dysfunction are driven by the activation of the P2Y6 receptor following the release of UDP, a danger signal, from intoxicated Caco-2 cells. Caco-2 cells express a functional P2Y6 receptor and release measurable amounts of UDP upon exposure to TcdA/B. Toxin-induced CXCL8/IL-8 production and release were attenuated in the presence of a selective P2Y6 inhibitor (MRS2578. This was associated with inhibition of TcdA/B-induced activation of NFκB. Blockade of the P2Y6 receptor also attenuated toxin-induced barrier dysfunction in polarized Caco-2 cells. Lastly, pretreating mice with the P2Y6 receptor antagonists (MSR2578 attenuated TcdA/B-induced inflammation and intestinal permeability in an intrarectal toxin exposure model. Taken together these data outline a novel role for the P2Y6 receptor in the induction of CXCL8/IL-8 production and barrier dysfunction in response to C. difficile toxin exposure and may provide a new therapeutic target for the treatment of CDI.

  14. Co action of CFTR and AQP1 increases permeability of peritoneal epithelial cells on estrogen-induced ovarian hyper stimulation syndrome

    Directory of Open Access Journals (Sweden)

    Jin Pei-Yin

    2012-08-01

    Full Text Available Abstract Background Ovarian hyper stimulation syndrome (OHSS is an iatrogenic complication associated with fertility drugs. It is characterized by increased vascular permeability and substantial fluid shift with accumulation in the body cavity. The pathogenesis of OHSS remains obscure, and no definitive treatments are currently available. Results Using western blot and short-circuit current (Isc techniques, we investigate the potential coactions of analysis in cystic fibrosis transmembrane conductance regulator (CFTR and aquaporin 1 (AQP1 on the hyper permeability of body cavity peritoneal epithelial cells in the pathogenesis of OHSS. The rats develop OHSS symptoms, with the up regulation of both CFTR and AQP1 expression and enhanced CFTR channel activity in peritoneal epithelial cells, can also be mimicked by administration of estrogen, alone in ovariectomized rats. Administration of progesterone suppresses CFTR activity, OHSS symptoms as well as CFTR and AQP1 expression. Besides, AQP1 inhibitor, HgCl2, can suppress CFTR channel activity. Therefore, antisera against CFTR or AQP1 to OHSS animals may result in alleviation of the symptom. Conclusion This study confirms the coactions of CFTR and AQP1 play a critical role in the development and progression of increased peritoneal epithelial permeability in severe OHSS. These findings may provide grounds for ameliorating assisted reproduction treatment strategy to reduce the risk of OHSS in in vitro fertilization (IVF.

  15. [Permeability of blood-brain barrier oxygen-glucose deprivation induced by tetramethylpyrazine-puerarin in vitro].

    Science.gov (United States)

    Li, Jinhui; Che, Lingyan; Wang, Yu; Zhang, Yuyan; Wan, Haitong; Yang, Jiehong

    2010-10-01

    To explore permeability of artificial blood-brain barrier (aBBB) by oxygen-glucose deprivation combined (OGD)-induced using tetramethylpyrazine combined with puerarin in vitro. Rats were divided into normal control group, model group, tetramethylpyrazine group, puerarin group, tetramethylpyrazine-puerarin group and nimodipine group. Culture rat brain microvascular endothelial cells and astrocytes in vitro and build the OGD-induced aBBB damage model. Evaluate aBBB damage characteristics by TEER, gamma-GT, AKP and LDH. Determine contents of tetramethylpyrazine, puerarin, nimodipine and calculate drug permeating concentration of OGD-induced aBBB model by HPLC. Compared with the model, the level of TEER was lower than the control group with significant difference (P permeability of the OGD-induced aBBB.

  16. In vivo assessment of the permeability of the blood-brain barrier and blood-retinal barrier to fluorescent indoline derivatives in zebrafish

    Directory of Open Access Journals (Sweden)

    Watanabe Kohei

    2012-08-01

    Full Text Available Abstract Background Successful delivery of compounds to the brain and retina is a challenge in the development of therapeutic drugs and imaging agents. This challenge arises because internalization of compounds into the brain and retina is restricted by the blood–brain barrier (BBB and blood-retinal barrier (BRB, respectively. Simple and reliable in vivo assays are necessary to identify compounds that can easily cross the BBB and BRB. Methods We developed six fluorescent indoline derivatives (IDs and examined their ability to cross the BBB and BRB in zebrafish by in vivo fluorescence imaging. These fluorescent IDs were administered to live zebrafish by immersing the zebrafish larvae at 7-8 days post fertilization in medium containing the ID, or by intracardiac injection. We also examined the effect of multidrug resistance proteins (MRPs on the permeability of the BBB and BRB to the ID using MK571, a selective inhibitor of MRPs. Results The permeability of these barriers to fluorescent IDs administered by simple immersion was comparable to when administered by intracardiac injection. Thus, this finding supports the validity of drug administration by simple immersion for the assessment of BBB and BRB permeability to fluorescent IDs. Using this zebrafish model, we demonstrated that the length of the methylene chain in these fluorescent IDs significantly affected their ability to cross the BBB and BRB via MRPs. Conclusions We demonstrated that in vivo assessment of the permeability of the BBB and BRB to fluorescent IDs could be simply and reliably performed using zebrafish. The structure of fluorescent IDs can be flexibly modified and, thus, the permeability of the BBB and BRB to a large number of IDs can be assessed using this zebrafish-based assay. The large amount of data acquired might be useful for in silico analysis to elucidate the precise mechanisms underlying the interactions between chemical structure and the efflux transporters at the

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Lenticular mitoprotection. Part B: GSK-3β and regulation of mitochondrial permeability transition for lens epithelial cells in atmospheric oxygen.

    Science.gov (United States)

    Brooks, Morgan M; Neelam, Sudha; Cammarata, Patrick R

    2013-01-01

    Loss of integrity of either the inner or outer mitochondrial membrane results in the dissipation of the mitochondrial electrochemical gradient that leads to mitochondrial membrane permeability transition (mMPT). This study emphasizes the role of glycogen synthase kinase 3beta (GSK-3β) in maintaining mitochondrial membrane potential, thus preventing mitochondrial depolarization (hereafter termed mitoprotection). Using 3-(2,4-dichlorophenyl)-4-(1-methyl-1H-indol-3-yl)-1H-pyrrole-2,5-dione (SB216763), an inhibitor of GSK-3β, and drawing a distinction between it and 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio] butadiene (UO126), an inhibitor of extracellular-signal-regulated kinase (ERK) phosphorylation, the means by which GSK-3β influences mitoprotection in cultured human lens epithelial (HLE-B3) cells and normal, secondary cultures of bovine lens epithelial cells, maintained in atmospheric oxygen, was investigated. Virally transfected human lens epithelial cells (HLE-B3) and normal cultures of bovine lens epithelial cells were exposed to acute hypoxic conditions (about 1% O2) followed by exposure to atmospheric oxygen (about 21% O2). Specific antisera and western blot analysis was used to examine the state of phosphorylation of ERK and GSK-3β, as well as the phosphorylation of a downstream substrate of GSK-3β, glycogen synthase (GS, useful in monitoring GSK-3β activity). The potentiometric dye, 1H-benzimidazolium-5,6-dichloro-2-[3-(5,6-dichloro-1,3-diethyl-1,3-dihydro-2H-benzimidazol-2-ylidene)-1-propenyl]-1,3-diethyl-iodide (JC-1), was used to monitor mitochondrial depolarization upon exposure of inhibitor treatment relative to the control cells (mock inhibition) in atmospheric oxygen. Caspase-3 activation was scrutinized to determine whether mitochondrial depolarization inevitably leads to apoptosis. Treatment of HLE-B3 cells with SB216763 (12 µM) inactivated GSK-3β activity as verified by the enzyme's inability to phosphorylate its substrate, GS. SB

  19. Excess soluble CD40L contributes to blood brain barrier permeability in vivo: implications for HIV-associated neurocognitive disorders.

    Directory of Open Access Journals (Sweden)

    Donna C Davidson

    Full Text Available Despite the use of anti-retroviral therapies, a majority of HIV-infected individuals still develop HIV-Associated Neurocognitive Disorders (HAND, indicating that host inflammatory mediators, in addition to viral proteins, may be contributing to these disorders. Consistently, we have previously shown that levels of the inflammatory mediator soluble CD40L (sCD40L are elevated in the circulation of HIV-infected, cognitively impaired individuals as compared to their infected, non-impaired counterparts. Recent studies from our group suggest a role for the CD40/CD40L dyad in blood brain barrier (BBB permeability and interestingly, sCD40L is thought to regulate BBB permeability in other inflammatory disorders of the CNS. Using complementary multiphoton microscopy and quantitative analyses in wild-type and CD40L deficient mice, we now reveal that the HIV transactivator of transcription (Tat can induce BBB permeability in a CD40L-dependent manner. This permeability of the BBB was found to be the result of aberrant platelet activation induced by Tat, since depletion of platelets prior to treatment reversed Tat-induced BBB permeability. Furthermore, Tat treatment led to an increase in granulocyte antigen 1 (Gr1 positive monocytes, indicating an expansion of the inflammatory subset of cells in these mice, which were found to adhere more readily to the brain microvasculature in Tat treated animals. Exploring the mechanisms by which the BBB becomes compromised during HIV infection has the potential to reveal novel therapeutic targets, thereby aiding in the development of adjunct therapies for the management of HAND, which are currently lacking.

  20. 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.

  1. Experimental chronic cerebral hypoperfusion results in decreased pericyte coverage and increased blood-brain barrier permeability in the corpus callosum.

    Science.gov (United States)

    Liu, Qinghai; Radwanski, Ryan; Babadjouni, Robin; Patel, Arati; Hodis, Drew M; Baumbacher, Peter; Zhao, Zhen; Zlokovic, Berislav; Mack, William J

    2017-01-01

    Murine chronic cerebral hypoperfusion (CCH) results in white matter (WM) injury and behavioral deficits. Pericytes influence blood-brain barrier (BBB) integrity and cerebral blood flow. Under hypoxic conditions, pericytes detach from perivascular locations increasing vessel permeability and neuronal injury. This study characterizes the time course of BBB dysfunction and pericyte coverage following murine experimental CCH secondary to bilateral carotid artery stenosis (BCAS). Mice underwent BCAS or sham operation. On post-procedure days 1, 3, 7 and 30, corpus callosum BBB permeability was characterized using Evans blue (EB) extravasation and IgG staining and pericyte coverage/count was calculated. The BCAS cohort demonstrated increased EB extravasation on postoperative days 1 ( p = 0.003) 3 ( p = 0.002), and 7 ( p = 0.001) when compared to sham mice. Further, EB extravasation was significantly greater ( p = 0.05) at day 3 than at day 30 in BCAS mice. BCAS mice demonstrated a nadir in pericyte coverage and count on post-operative day 3 ( p < 0.05, compared to day 7, day 30 and sham). Decreased pericyte coverage/count and increased BBB permeability are most pronounced on postoperative day 3 following murine CCH. This precedes any notable WM injury or behavioral deficits.

  2. Functional consequences of neuromyelitis optica-IgG astrocyte interactions on blood-brain barrier permeability and granulocyte recruitment.

    Science.gov (United States)

    Vincent, Thierry; Saikali, Philippe; Cayrol, Romain; Roth, Alejandro D; Bar-Or, Amit; Prat, Alexandre; Antel, Jack P

    2008-10-15

    Autoantibody neuromyelitis optica-IgG (NMO-IgG) recognizing aquaporin-4 (AQP4) is implicated as playing a central role in the physiopathology of NMO. The aim of this in vitro-based study was to characterize functional consequences of interaction between NMO-IgG and cells of the neurovascular unit (astrocytes and brain endothelium) that would provide insight into recognized features of NMO, namely altered blood-brain barrier (BBB) permeability and granulocyte recruitment. We used sera from NMO and longitudinally extensive transverse myelitis cases shown to bind in a characteristic perivascular pattern to primate cerebellar slices. Using flow cytometry, we found that sera from NMO-IgG-positive patients reacted with CNS-derived human fetal astrocytes, whereas sera from multiple sclerosis patients did not. We demonstrated that NMO-IgG binding to astrocytes alters aquaporin-4 polarized expression and increases permeability of a human BBB endothelium/astrocyte barrier. We further demonstrated that NMO-IgG binding to human fetal astrocytes can result in NK cell degranulation, astrocyte killing by Ab-dependent cellular cytotoxicity and complement-dependent granulocyte attraction through the BBB model. Our study highlights important functional roles for NMO-IgG that could account for pathological lesions and BBB dysfunction observed in NMO.

  3. Evaluation of a horizontal permeable reactive barrier for preventing upward diffusion of volatile organic compounds through the unsaturated zone.

    Science.gov (United States)

    Mahmoodlu, Mojtaba G; Hassanizadeh, S Majid; Hartog, Niels; Raoof, Amir; van Genuchten, Martinus Th

    2015-11-01

    Permeable reactive barriers are commonly used to treat contaminant plumes in the saturated zone. However, no known applications of horizontal permeable reactive barriers (HPRBs) exist for oxidizing volatile organic compounds (VOCs) in the unsaturated zone. In this study, laboratory column experiments were carried out to investigate the ability of a HPRB containing solid potassium permanganate, to oxidize the vapors of trichloroethylene (TCE), toluene, and ethanol migrating upward from a contaminated saturated zone. Results revealed that an increase in initial water saturation and HPRB thickness strongly affected the removal efficiency of the HPRB. Installing the HPRB relatively close to the water table was more effective due to the high background water content and enhanced diffusion of protons and/or hydroxides away from the HPRB. Inserting the HPRB far above the water table caused rapid changes in pH within the HPRB, leading to lower oxidation rates. The pH effects were included in a reactive transport model, which successfully simulated the TCE and toluene experimental observations. Simulations for ethanol were not affected by pH due to condensation of water during ethanol oxidation, which caused some dilution in the HRPB. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 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.

  5. Chlamydia trachomatis regulates innate immune barrier integrity and mediates cytokine and antimicrobial responses in human uterine ECC-1 epithelial cells.

    Science.gov (United States)

    Mukura, Lucy Rudo; Hickey, Danica K; Rodriguez-Garcia, Marta; Fahey, John V; Wira, Charles R

    2017-12-01

    Chlamydia trachomatis infection is the most common sexually transmitted bacterial infection worldwide and known to increase the risk for HIV acquisition. Few studies have investigated how infection of epithelial cells compromises barrier integrity and antimicrobial response. ECC-1 cells, a human uterine epithelial cell line, were treated with live and heat-killed C. trachomatis. Epithelial barrier integrity measured as transepithelial resistance (TER), chemokines antimicrobial levels, and antimicrobial mRNA expression was measured by ELISA and Real-time RT-PCR. Epithelial barrier integrity was compromised when cells were infected with live, but not with heat-killed, C. trachomatis. IL-8 secretion by ECC-1 cells increased in response to live and heat-killed C. trachomatis, while MCP-1, HBD2 and trappin2/elafin secretion decreased with live C. trachomatis. Live C. trachomatis suppresses ECC-1 innate immune responses by compromising the barrier integrity, inhibiting secretion of MCP-1, HBD2, and trappin-2/elafin. Differential responses between live and heat-killed Chlamydia indicate which immune responses are dependent on ECC-1 infection rather than the extracellular presence of Chlamydia. © 2017 John Wiley & Sons A/S Published by John Wiley & Sons Ltd.

  6. The rights and wrongs of blood-brain barrier permeability studies: a walk through 100 years of history

    Directory of Open Access Journals (Sweden)

    Norman Ruthven Saunders

    2014-12-01

    Full Text Available 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. The first person to use this term seems to be Stern in the early 1920s. Studies in embryos by Stern & colleagues, Weed and Wislocki showed results similar to those in adult animals. These were well-conducted experiments made a century ago, thus the persistence of a belief in barrier immaturity is puzzling. As discussed in this review, evidence for this belief, is of poor experimental quality, often misinterpreted and often not properly cited. The functional state of blood-brain barrier mechanisms in the fetus is an important biological phenomenon with implications for normal brain development. It is also important for clinicians to have proper evidence on which to advise pregnant women who may need to take medications for serious medical conditions. Beliefs in immaturity of the blood-brain barrier have held the field back for decades. Their history illustrates the importance of taking account of all the evidence and assessing its quality, rather than selecting papers that supports a preconceived notion or intuitive belief. This review attempts to right the

  7. A theory for the impact of a wave breaking onto a permeable barrier with jet generation

    OpenAIRE

    Cooker, MJ

    2013-01-01

    We model a water wave impact onto a porous breakwater. The breakwater surface is modelled as a thin barrier composed of solid matter pierced by channels through which water can flow freely. The water in the wave is modelled as a finite-length volume of inviscid, incompressible fluid in quasi-one-dimensional flow during its impact and flow through a typical hole in the barrier. The fluid volume moves at normal incidence to the barrier. After the initial impact the wave water starts to slow dow...

  8. Permeability dependence study of the focused ultrasound-induced blood-brain barrier opening at distinct pressures and microbubble diameters using DCE-MRI.

    Science.gov (United States)

    Vlachos, Fotios; Tung, Yao-Sheng; Konofagou, Elisa

    2011-09-01

    Blood-brain barrier opening using focused ultrasound and microbubbles has been experimentally established as a noninvasive and localized brain drug delivery technique. In this study, the permeability of the opening is assessed in the murine hippocampus after the application of focused ultrasound at three different acoustic pressures and microbubble sizes. Using dynamic contrast-enhanced MRI, the transfer rates were estimated, yielding permeability maps and quantitative K(trans) values for a predefined region of interest. The volume of blood-brain barrier opening according to the K(trans) maps was proportional to both the pressure and the microbubble diameter. A K(trans) plateau of ∼0.05 min(-1) was reached at higher pressures (0.45 and 0.60 MPa) for the larger sized bubbles (4-5 and 6-8 μm), which was on the same order as the K(trans) of the epicranial muscle (no barrier). Smaller bubbles (1-2 μm) yielded significantly lower permeability values. A small percentage (7.5%) of mice showed signs of damage under histological examination, but no correlation with permeability was established. The assessment of the blood-brain barrier permeability properties and their dependence on both the pressure and the microbubble diameter suggests that K(trans) maps may constitute an in vivo tool for the quantification of the efficacy of the focused ultrasound-induced blood-brain barrier opening. Copyright © 2011 Wiley-Liss, Inc.

  9. Study of the interactions bacteria - phenanthrene - activated carbon for the preparation of a permeable reactive barrier; Etude des interactions bacteries - phenanthrene - charbon en vue de l'elaboration d'une barriere permeable reactive

    Energy Technology Data Exchange (ETDEWEB)

    Leglize, P.

    2004-12-01

    Permeable Reactive Barrier (PRB) is a new way for the remediation of contaminated groundwater, but up to now Polycyclic Aromatic Hydrocarbons (PAHs) were rarely considered. We investigated PAH - bacteria - materials interactions in order to validate the feasibility of PRB for PAH contamination. PHE Adsorption/desorption kinetics onto different materials, activated carbons (CA), pozzolana (Pz) and pozzolana coated with heavy fuel (PzF), were investigated. PHE biodegradation were performed on batch using PAH degrading bacteria and the PRB materials. CA was a good media for PRB process: Phenanthrene sorption capacity is 100 to 10000 fold higher than PzF and Pz. Phenanthrene mineralization with CA was higher than without material. Bacterial properties affected PHE biodegradation. Bio-film production improved PHE biodegradation by PAH degrading bacteria. Column studies showed that inoculation of the column improved its efficiency: adsorbed PHE degradation and increased retardation of PHE. (author)

  10. 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

  11. Determination of hexavalent chromium reduction using Cr stable isotopes: isotopic fractionation factors for permeable reactive barrier materials.

    Science.gov (United States)

    Basu, Anirban; Johnson, Thomas M

    2012-05-15

    Cr stable isotope measurements can provide improved estimates of the extent of Cr(VI) reduction to less toxic Cr(III). The relationship between observed (53)Cr/(52)Cr ratio shifts and the extent of reduction can be calibrated by determining the isotopic fractionation factor for relevant reactions. Permeable reactive barriers (PRB) made of Fe(0) and in situ redox manipulation (ISRM) zones effectively remediate Cr-contaminated aquifers. Here, we determine the isotopic fractionations for dominant reductants in reactive barriers and reduced sediments obtained from an ISRM zone at the US DOE's Hanford site. In all cases, significant isotopic fractionation was observed; fractionation (expressed as ε) was -3.91‰ for Fe(II)-doped goethite, -2.11‰ for FeS, -2.65‰ for green rust, -2.67‰ for FeCO(3), and -3.18‰ for ISRM zone sediments. These results provide a better calibration of the relationship between Cr isotope ratios and the extent of Cr(VI) reduction and aid in interpretation of Cr isotope data from systems with reactive barriers.

  12. Blood-Brain Barrier Permeability of Normal Appearing White Matter in Relapsing-Remitting Multiple Sclerosis

    DEFF Research Database (Denmark)

    Lund, Henrik; Krakauer, Martin; Skimminge, Arnold

    2013-01-01

    and after the intravenous injection of a paramagnetic contrast agent to assess BBB permeability in the normal appearing white matter (NAWM) in patients with relapsing-remitting MS (RR-MS). Methodology/Principal Findings: Fifty-nine patients (38 females) with RR-MS undergoing immunomodulatory treatment...... and nine healthy controls (4 females) underwent quantitative T1 measurements at 3 tesla before and after injection of a paramagnetic contrast agent (0.2 mmol/kg Gd-DTPA). Mean T1 values were calculated for NAWM in patients and total cerebral white matter in healthy subjects for the T1 measurements before...

  13. Topical antihistamines display potent anti-inflammatory activity linked in part to enhanced permeability barrier function

    DEFF Research Database (Denmark)

    Lin, Tzu-Kai; Man, Mao-Qiang; Santiago, Juan-Luis

    2013-01-01

    antagonists likely oppose mast cell-derived histamines. In four immunologically diverse, murine disease models, characterized by either inflammation alone (acute irritant contact dermatitis, acute allergic contact dermatitis) or by prominent barrier abnormalities (subacute allergic contact dermatitis, atopic...... of epidermal differentiation, leading to thickened cornified envelopes; and (ii) enhanced epidermal lipid synthesis and secretion. As barrier homeostasis was enhanced to a comparable extent in mast cell-deficient mice, with no further improvement following application of topical H1/2r antagonists, H1/2r...... dermatitis), topical H1/2r agonists aggravated, whereas H1/2r antagonists improved, inflammation and/or barrier function. The apparent ability of topical H1r/2r antagonists to target epidermal H1/2r could translate into increased efficacy in the treatment of inflammatory dermatoses, likely due to decreased...

  14. Creation of a subsurface permeable treatment barrier using in situ redox manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Fruchter, J.S.; Cole, C.R.; Williams, M.D. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    1997-12-31

    The goal of in situ redox manipulation is to create a permeable treatment zone in the subsurface for remediating redox-sensitive contaminants in groundwater. The permeable treatment zone is created just downstream of the contaminant plume or contaminant source through the injection of reagents and/or microbial nutrients to alter the redox potential of the aquifer fluids and sediments. Contaminant plumes migrating through this manipulated zone can then be destroyed or immobilized. In a field test at the Hanford Site, {approximately}77,000 L of buffered sodium dithionite solution were successfully injected into the unconfined aquifer at the 100-H Area in September 1995. The target contaminant was chromate. No significant plugging of the well screen or the formation was detected during any phase of the test. Dithionite was detected in monitoring wells at least 7.5 m from the injection point. Data were obtained from all three phases of the test (i.e., injection, reaction, withdrawal). Preliminary core data show that from 60% to 100% of the available reactive iron in the targeted aquifer sediments was reduced by the injected dithionite. One year after the injection, groundwater in the treatment zone remains anoxic. Total and hexavalent chromium levels in groundwater have been reduced from a preexperiment concentration of {approximately}60 {mu}g/L to below the detection limit of the analytical methods.

  15. Diel coral reef acidification driven by porewater advection in permeable sands, Heron Island, Great Barrier Reef

    DEFF Research Database (Denmark)

    Santos, Isaac R.; Glud, Ronnie N.; Maher, Damien

    2011-01-01

    Little is known about how biogeochemical processes in permeable sediments affect the pH of coastal waters. We demonstrate that seawater recirculation in permeable sands can play a major role in proton (H+) cycling in a coral reef lagoon. The diel pH range (up to 0.75 units) in the Heron Island...... lagoon was the broadest ever reported for reef waters, and the night‐time pH (7.69) was comparable to worst‐case scenario predictions for seawater pH in 2100. The net contribution of coarse carbonate sands to the whole system H+ fluxes was only 9% during the day, but approached 100% at night when small...... scale (i.e., flow and topography‐induced pressure gradients) and large scale (i.e., tidal pumping as traced by radon) seawater recirculation processes were synergistic. Reef lagoon sands were a net sink for H+, and the sink strength was a function of porewater flushing rate. Our observations suggest...

  16. PERMEABLE REACTIVE BARRIER PERFORMANCE MONITORING: LONG-TERM TRENDS IN GEOCHEMICAL PARAMETERS AT TWO SITES

    Science.gov (United States)

    A major goal of research on the long-term performance of subsurface reactive barriers is to identify standard ground-water monitoring parameters that may be useful indicators of declining performance or impending system failure. Results are presented from studies conducted over ...

  17. 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

    important for clinicians to have proper evidence on which to advise pregnant women who may need to take medications for serious medical conditions. Beliefs in immaturity of the blood-brain barrier have held the field back for decades. Their history illustrates the importance of taking account of all...

  18. Lack of IL-6 increases blood–brain barrier permeability in fungal ...

    Indian Academy of Sciences (India)

    − mice ... Interleukin (IL-6) is a multifunctional cytokine, and numerous studies have shown that IL‐6 influences the integrity of the blood–brain barrier. In this study we ... Dates. Manuscript received: 16 June 2014; Accepted: 10 November 2014 ...

  19. 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...... indicated the presence of a microbial consortium in the barrier. A wide range of species were identified including sulfate and iron reducing bacteria, together with Dehalococcoides and Desulfuromonas species indicating microbial reductive dehalogenation potential. The microbes had a profound effect...

  20. Observations of Anomalous Subcrustal Reflections Along the East Pacific Rise: Possible Detection of a Melt Permeability Barrier

    Science.gov (United States)

    Arnoux, G. M.; Toomey, D. R.

    2013-12-01

    Crustal accretion at mid-ocean ridges primarily occurs within the narrow neovolcanic zone at the spreading axis, with supplementary lower crustal accumulation thought to originate from the crystallization of magma bodies at the base of the crust. The narrowness of the neovolcanic zone requires melt focusing - a process that has been proposed to arise from the presence of melt impermeable boundaries, or permeability barriers, within the thermal boundary layer near the base of the lithosphere that inhibit the upward migration of melt, effectively focusing it laterally to the ridge axis. Numerical simulations, as well as structural and petrological characteristics of the Oman ophiolite, suggest the existence of such melt impermeable boundaries. A recent analysis of seismic data from the East Pacific Rise (EPR) between the Siqueiros and Clipperton transform faults (8°15'N-10°20'N) reveals anomalous subcrustal reflections ~20 km east of the rise axis and ~20-50 km south of the Clipperton transform. The reflections are characterized by large amplitudes, high frequency content on the order of 20-30 Hz, and a travel time curve that is parabolic with arrival times increasing rapidly at ranges <20 km from the receiver. The approximate depth, slope, and geographical extent of the reflector are estimated by back projecting the onset times of the anomalous reflections into a predefined velocity model. This method reveals that the reflector dips both away from the ridge axis and northward toward the Clipperton transform with a minimum depth below seafloor of ~7.2 km (0.7 km below the Moho) nearest to the ridge. Further off-axis and roughly 20 km to the north, closest to the Clipperton transform, the depth of the reflector increases to ~10.6 km (4 km below the Moho). The slope of the observed reflector thus conforms to the base of the thermal boundary layer (i.e. the 1200-1300° C isotherms) in thermal models adjacent to oceanic transform faults (Roland et al., 2010). The 1240

  1. In situ construction of low permeable barrier in soil to prevent pollutant migration by applying weak electric field.

    Science.gov (United States)

    Chen, Si; Liu, Xiang; Wang, Li; Wan, Chunli

    2017-05-15

    In order to prevent vertical migration of pollutant in soil matrix, this study firstly proposed to construct an in situ low permeable barrier (LPB) through synchronously transporting calcium and carbonate. After LPB construction, the soil permeability was declined tenfold. Exchangeable calcium (37.3%) and calcium bonding to carbonate (41.7%) respectively alleviated flocculation of microaggregates and cementation of marcoaggregates. Accordingly, smaller particles (2 mm) after electrokinetic remediation. The other soil characters like pH, moisture, and bacterial communities were well preserved after remediation. In addition, the pollutant prevention was divided into two phases as unsaturated phase and saturated phase. In unsaturated phase, phenol, F(-), Cd(2+), and Ni(2+) in filtrate were all lower than 0.1 mg, and Cr2O4(2-)-Cr discharged from LPB was 1/5.1 than that from initial soil. In saturated phase, LPB prevented 4.3-12.1 fold pollutant than initial soil. Taken together, proposed method could effectively prevent vertical migration of pollutants, indicating significant values for saving soil remediation cost or avoiding contamination of underground water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. 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.

  3. Remodeling of Tight Junctions and Enhancement of Barrier Integrity of the CACO-2 Intestinal Epithelial Cell Layer by Micronutrients.

    Science.gov (United States)

    Valenzano, Mary Carmen; DiGuilio, Katherine; Mercado, Joanna; Teter, Mimi; To, Julie; Ferraro, Brendan; Mixson, Brittany; Manley, Isabel; Baker, Valerissa; Moore, Beverley A; Wertheimer, Joshua; Mullin, James M

    2015-01-01

    The micronutrients zinc, quercetin, butyrate, indole and berberine were evaluated for their ability to induce remodeling of epithelial tight junctions (TJs) and enhance barrier integrity in the CACO-2 gastrointestinal epithelial cell culture model. All five of these chemically very diverse micronutrients increased transepithelial electrical resistance (Rt) significantly, but only berberine also improved barrier integrity to the non-electrolyte D-mannitol. Increases of Rt as much as 200% of untreated controls were observed. Each of the five micronutrients also induced unique, signature-like changes in TJ protein composition, suggesting multiple pathways (and TJ arrangements) by which TJ barrier function can be enhanced. Decreases in abundance by as much as 90% were observed for claudin-2, and increases of over 300% could be seen for claudins -5 and -7. The exact effects of the micronutrients on barrier integrity and TJ protein composition were found to be highly dependent on the degree of differentiation of the cell layer at the time it was exposed to the micronutrient. The substratum to which the epithelial layer adheres was also found to regulate the response of the cell layer to the micronutrient. The implications of these findings for therapeutically decreasing morbidity in Inflammatory Bowel Disease are discussed.

  4. Remodeling of Tight Junctions and Enhancement of Barrier Integrity of the CACO-2 Intestinal Epithelial Cell Layer by Micronutrients

    Science.gov (United States)

    Valenzano, Mary Carmen; DiGuilio, Katherine; Mercado, Joanna; Teter, Mimi; To, Julie; Ferraro, Brendan; Mixson, Brittany; Manley, Isabel; Baker, Valerissa; Moore, Beverley A.; Wertheimer, Joshua; Mullin, James M.

    2015-01-01

    The micronutrients zinc, quercetin, butyrate, indole and berberine were evaluated for their ability to induce remodeling of epithelial tight junctions (TJs) and enhance barrier integrity in the CACO-2 gastrointestinal epithelial cell culture model. All five of these chemically very diverse micronutrients increased transepithelial electrical resistance (Rt) significantly, but only berberine also improved barrier integrity to the non-electrolyte D-mannitol. Increases of Rt as much as 200% of untreated controls were observed. Each of the five micronutrients also induced unique, signature-like changes in TJ protein composition, suggesting multiple pathways (and TJ arrangements) by which TJ barrier function can be enhanced. Decreases in abundance by as much as 90% were observed for claudin-2, and increases of over 300% could be seen for claudins -5 and -7. The exact effects of the micronutrients on barrier integrity and TJ protein composition were found to be highly dependent on the degree of differentiation of the cell layer at the time it was exposed to the micronutrient. The substratum to which the epithelial layer adheres was also found to regulate the response of the cell layer to the micronutrient. The implications of these findings for therapeutically decreasing morbidity in Inflammatory Bowel Disease are discussed. PMID:26226276

  5. Regulation of human epithelial tight junction proteins by Lactobacillus plantarum in vivo and protective effects on the epithelial barrier

    NARCIS (Netherlands)

    Karczewski, J.; Troost, F.J.; Konings, I.; Dekker, J.; Kleerebezem, M.; Brummer, R.J.; Wells, J.

    2010-01-01

    Lactobacillus plantarum, a commensal bacterium of humans, has been proposed to enhance the intestinal barrier, which is compromised in a number of intestinal disorders. To study the effect of L. plantarum strain WCFS1 on human barrier function, healthy subjects were administered L. plantarum or

  6. Transient and local increase in the permeability of the blood-brain barrier and the blood-retinal barrier by hyperthermia of magnetic nanoparticles in a rat model

    Science.gov (United States)

    Tabatabaei Shafie, Seyed Nasrollah

    After successfully propelling therapeutic agents encapsulated in magnetic micro-carriers to a specific location inside an animal model by the gradient magnetic field of a modified clinical Magnetic Resonance (MR) scanner, we are now aiming to perform local drug delivery in the region of the central nervous system (CNS). To achieve localized drug delivery and increase efficacy, this project advances the theme that the therapeutic agents must be administered by means no more invasive than an intravenous injection followed by remote propulsion, controlled tracking, and on-command actuation in the CNS. The demanding function of the CNS requires an extremely stable environment. In fact, any small change in the composition of the interstitial fluid in the CNS plays a predominant role in regulating its microenvironment and neuronal activity. Therefore, the CNS is conceived to protect itself from frequent fluctuations of extracellular concentration of hormones, amino acids, and ion levels that occur after meals, exercise, or stress - as well as from toxic pathogens that may be circulating in the blood stream. This preventive barrier consists mainly of tightly interconnected endothelial cells that carpet the inner surface of most blood vessels in the CNS. While it provides a stable neuronal environment, more than 98% of all drug molecules are not able to cross this barrier and the extent to which a molecule enters is determined only by the permeability characteristics of the barrier. Therefore, while pharmaceutical research progresses for drug delivery to the CNS, it is limited by its pharmacokinetics through physiological barriers. Successful transient and local opening of the barrier for diffusion of therapeutics could strongly support the feasibility of treating a variety of neurological disorders. A recent effort presented in this dissertation provides evidence for the emergence of a novel approach to overcome this problem. This technique uses magnetic nanoparticles

  7. Outer membrane vesicles and soluble factors released by probiotic Escherichia coli Nissle 1917 and commensal ECOR63 enhance barrier function by regulating expression of tight junction proteins in intestinal epithelial cells

    Directory of Open Access Journals (Sweden)

    Carina Shianya Alvarez

    2016-12-01

    Full Text Available The gastrointestinal epithelial layer forms a physical and biochemical barrier that maintains the segregation between host and intestinal microbiota. The integrity of this barrier is critical in maintaining homeostasis in the body and its dysfunction is linked to a variety of illnesses, especially inflammatory bowel disease. Gut microbes, and particularly probiotic bacteria, modulate the barrier integrity by reducing gut permeability and reinforcing tight junctions. Probiotic Escherichia coli Nissle 1917 (EcN is a good colonizer of the human gut with proven therapeutic efficacy in the remission of ulcerative colitis in humans. EcN positively modulates the intestinal epithelial barrier through upregulation and redistribution of the tight junction proteins ZO-1, ZO-2 and claudin-14. Upregulation of claudin-14 has been attributed to the secreted protein TcpC. Whether regulation of ZO-1 and ZO-2 is mediated by EcN secreted factors remains unknown. The aim of this study was to explore whether outer membrane vesicles (OMVs released by EcN strengthen the epithelial barrier. This study includes other E. coli strains of human intestinal origin that contain the tcpC gene, such as ECOR63. Cell-free supernatants collected from the wild-type strains and from the derived tcpC mutants were fractionated into isolated OMVs and soluble secreted factors. The impact of these extracellular fractions on the epithelial barrier was evaluated by measuring transepithelial resistance and expression of several tight junction proteins in T84 and Caco-2 polarized monolayers. Our results show that the strengthening activity of EcN and ECOR63 does not exclusively depend on TcpC. Both OMVs and soluble factors secreted by these strains promote upregulation of ZO-1 and claudin-14, and down-regulation of claudin-2. The OMVs-mediated effects are TcpC-independent. Soluble secreted TcpC contributes to the upregulation of ZO-1 and claudin-14, but this protein has no effect on the

  8. 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

  9. Role of Vitamin D in Maintaining Renal Epithelial Barrier Function in Uremic Conditions

    Directory of Open Access Journals (Sweden)

    Milos Mihajlovic

    2017-11-01

    Full Text Available As current kidney replacement therapies are not efficient enough for end-stage renal disease (ESRD treatment, a bioartificial kidney (BAK device, based on conditionally immortalized human proximal tubule epithelial cells (ciPTEC, could represent an attractive solution. The active transport activity of such a system was recently demonstrated. In addition, endocrine functions of the cells, such as vitamin D activation, are relevant. The organic anion transporter 1 (OAT-1 overexpressing ciPTEC line presented 1α-hydroxylase (CYP27B1, 24-hydroxylase (CYP24A1 and vitamin D receptor (VDR, responsible for vitamin D activation, degradation and function, respectively. The ability to produce and secrete 1α,25-dihydroxy-vitamin D3, was shown after incubation with the precursor, 25-hydroxy-vitamin D3. The beneficial effect of vitamin D on cell function and behavior in uremic conditions was studied in the presence of an anionic uremic toxins mixture. Vitamin D could restore cell viability, and inflammatory and oxidative status, as shown by cell metabolic activity, interleukin-6 (IL-6 levels and reactive oxygen species (ROS production, respectively. Finally, vitamin D restored transepithelial barrier function, as evidenced by decreased inulin-FITC leakage in biofunctionalized hollow fiber membranes (HFM carrying ciPTEC-OAT1. In conclusion, the protective effects of vitamin D in uremic conditions and proven ciPTEC-OAT1 endocrine function encourage the use of these cells for BAK application.

  10. The phenotype of the human materno-fetal endothelial barrier: molecular occupancy of paracellular junctions dictate permeability and angiogenic plasticity.

    Science.gov (United States)

    Leach, Lopa

    2002-06-01

    In vitro models predict that molecular occupancy of endothelial junctions may regulate both barrier function and angiogenesis. Whether this is true in human vascular beds undergoing physiological angiogenesis has not been shown. This review presents data which demonstrate there are two distinct junctional phenotypes, 'activated' and 'stable', present in the vascular tree of the human placenta taken from two distinct highly angiogenic gestational periods (first and last trimester). Stability is conferred by the presence of occludin in tight junctions and plakoglobin in adherens junctions. Their localization may be influenced by vascular endothelial growth factor and angiopoietins 1 and 2 that have a similar temporal and site-specific differential expression. The junctional phenotypes are reversible, as shown in studies with endothelial cells isolated from placental microvessels and grown in the presence/absence of cAMP-enhancing agents. Reductions in protein levels and loss of junctional localization of adhesion molecules result in increased permeability to macromolecules, whilst up-regulation and re-targeting of these molecules inhibit cell proliferation and increase transendothelial resistance. These studies suggest junctional adhesion molecules can regulate physiological angiogenesis and vascular re-modelling. Moreover, the activated junctional phenotype of placental microvessels allows them to participate in increased growth and proliferation. This junctional immaturity appears to be at the expense of barrier function resulting in sites of maximal materno-fetal solute exchange.

  11. Remediation of chromium-contaminated soil by electrokinetics and electrokinetics coupled with CaAl-LDH permeable reaction barrier.

    Science.gov (United States)

    Xu, Yunfeng; Xia, Wei; Hou, Hetian; Zhang, Jia; Qian, Guangren

    2017-09-01

    The remediation of Cr(VI)-contaminated soil was investigated by electrokinetic (EK) and permeable-reactive-barrier assisted electrokinetic (EK-PRB). The medium of PRB was hydrocalumite (CaAl-LDH). The results showed that removal efficiency of hexavalent chromium (Cr(VI)) in EK-PRB and EK system was 96.49 and 85.50%, respectively. Simultaneously, the removal efficiency of total chromium (TCr) was 69.34 and 40.97% after 120-h treatment. The XRD, FTIR, and XPS analyses indicated that the reactive barrier media of CaAl-LDH successfully captured the chromium. Besides, the migration rate of chromium in EK-PRB was relatively faster than EK, since the media of PRB captured chromium in-time and reduced the influence of chromium accumulation on the migration of chromium. Moreover, the trivalent chromium (Cr(III)) was generated in EK/EK-PRB, and the chromium was stabilized in soil with the chemical speciations of oxidizable and residual fractions. Therefore, the treatment of EK-PRB and EK both increased the removal of chromium and decreased its environmental risks.

  12. Transient blood-brain barrier permeability following profound temporary global ischemia: an experimental study using /sup 14/C-AIB

    Energy Technology Data Exchange (ETDEWEB)

    Dobbin, J.; Crockard, H.A.; Ross-Russell, R.

    1989-02-01

    The influence of reperfusion after profound incomplete forebrain ischemia on blood-brain barrier (BBB) permeability to a small protein tracer was studied in male Sprague-Dawley rats. The mean cortical blood to brain transfer constant (Ki) for /sup 14/C-amino isobutyric acid (AIB) was significantly greater at 3 and 6 h of reperfusion, 2.5 times the mean values of controls (p less than 0.05) (2.5 microliter g-1 min-1 and 1.0 microliters g-1 min-1 respectively), but had returned to control values after reperfusion for 24 h. Analysis of distribution of Ki values showed that following 15 min and 30 min of profound ischemia, there was a significant increase in transfer of AIB across the blood-brain barrier (BBB) after recirculation for up to 6 h, though there was no evidence of protein extravasation as assessed by Evans Blue (EB) dye. After 24 h of reperfusion, the BBB to AIB was restored, and Ki values had returned to control values. It is concluded that following transient global ischemia, the BBB may recover rapidly.

  13. [Establishment of MDCK-pHaMDR cell model and standard operation procedure for assessing blood-brain barrier permeability of chemical components of traditional Chinese medicine].

    Science.gov (United States)

    Yang, Yan-Fang; Wu, Ni; Yang, Xiu-Wei

    2016-07-01

    To establish MDCK-pHaMDR cell model and standard operation procedure for assessing the blood-brain barrier permeability of chemical components of traditional Chinese medicine. MDCK-pHaMDR cell model was evaluated by determining the morphology features, transepithelial electrical resistance, bidirectional transport and intracellular accumulation of Rhodamine 123 and the apparent permeability of positive control drugs caffeine and atenolol. The MDCK-pHaMDR cell model had satisfactory integrity and tightness, and stable expression of P-gp. In addition, the transport results of the positive control drugs were consistent with the reported values in literature. All the parameters tested of the MDCK-pHaMDR cell model were consistent with the requirements, so the model can be used to study the blood-brain barrier permeability of chemical components of traditional Chinese medicine. Copyright© by the Chinese Pharmaceutical Association.

  14. 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 ...

  15. ENVIRONMENTAL RESEARCH BRIEF: LONG-TERM PERFORMANCE OF PERMEABLE REACTIVE BARRIERS USING ZERO-VALENT IRON: AN EVALUATION AT TWO SITES

    Science.gov (United States)

    Geochemical and microbiological factors that control long-term performance of subsurface permeable reactive barriers were evaluated at the Elizabeth City, NC and the Denver Federal Center, CO sites. These groundwater treatment systems use zero-valent iron filings to intercept an...

  16. 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 ...

  17. Caveolin-1 expression regulates blood-retinal barrier permeability and retinal neovascularization in oxygen-induced retinopathy.

    Science.gov (United States)

    Tian, Xiao-Feng; Xia, Xiao-Bo; Xu, Hui-Zhuo; Xiong, Si-Qi; Jiang, Jian

    2012-01-01

    Caveolin-1 expression correlates with the permeability of endothelial barriers and angiogenesis. However, the role of caveolin-1 in retinal neovascularization remains unknown. We evaluated the effect of caveolin-1 on the blood-retina barrier and retinal neovascularization in a murine model of oxygen-induced retinopathy. Starting at postnatal day 7, mice were exposed to 75 ± 5% oxygen for 5 days and then returned to room air conditions to induce retinal neovascularization. Effects on blood-retina barrier were evaluated by Western blot analysis of extravasated albumin in the retina. Retinal neovascularization morphology was studied by fluorescence angiography and was quantified by counts of the endothelial nuclei that protruded into the vitreous cavity. Reverse transcription-polymerase chain reaction and Western blot analysis was used to examine retinal expression levels of caveolin-1. siRNA against caveolin-1 was injected intravitreally in the oxygen-induced retinopathy models. Effects on caveolin-1 mRNA and protein, and retinal neovascularization were assessed as described above. Caveolin-1 expression was found to increase during hypoxia and overexpression of caveolin-1 correlated with the appearance of extravascular albumin. Caveolin-1 siRNA reduced caveolin-1 mRNA and protein levels by 47.94% and 54.76%, respectively. Furthermore, caveolin-1 siRNA inhibition reduced retinal neovascularization by 51.3% and reduced albumin leakage by 56.32%. Caveolin-1 may play an important role in induction of retinal neovascularization. SiRNA against caveolin-1 can inhibit experimental retinal hyperpermeability and neovascularization. Therefore, the inhibition of caveolin-1 may be a powerful and novel therapeutic tool for the treatment of ischaemia-induced retinal diseases. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

  18. Permeable reactive barriers for the remediation of groundwater in a mining area: results for a pilot-scale project

    Science.gov (United States)

    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

  19. Dai-Huang-Fu-Zi-Tang Alleviates Intestinal Injury Associated with Severe Acute Pancreatitis by Regulating Mitochondrial Permeability Transition Pore of Intestinal Mucosa Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Xin Kang

    2017-01-01

    Full Text Available Objective. The aim of the present study was to examine whether Dai-Huang-Fu-Zi-Tang (DHFZT could regulate mitochondrial permeability transition pore (MPTP of intestinal mucosa epithelial cells for alleviating intestinal injury associated with severe acute pancreatitis (SAP. Methods. A total of 72 Sprague-Dawley rats were randomly divided into 3 groups (sham group, SAP group, and DHFZT group, n=24 per group. The rats in each group were divided into 4 subgroups (n=6 per subgroup accordingly at 1, 3, 6, and 12 h after the operation. The contents of serum amylase, D-lactic acid, diamine oxidase activity, and degree of MPTP were measured by dry chemical method and enzyme-linked immunosorbent assay. The change of mitochondria of intestinal epithelial cells was observed by transmission electron microscopy. Results. The present study showed that DHFZT inhibited the openness of MPTP at 3, 6, and 12 h after the operation. Meanwhile, it reduced the contents of serum D-lactic acid and activity of diamine oxidase activity and also drastically relieved histopathological manifestations and epithelial cells injury of intestine. Conclusion. DHFZT alleviates intestinal injury associated SAP via reducing the openness of MPTP. In addition, DHFZT could also decrease the content of serum diamine oxidase activity and D-lactic acid after SAP.

  20. Pharmacological modulation of blood-brain barrier increases permeability of doxorubicin into the rat brain

    Science.gov (United States)

    Sardi, Iacopo; la Marca, Giancarlo; Cardellicchio, Stefania; Giunti, Laura; Malvagia, Sabrina; Genitori, Lorenzo; Massimino, Maura; de Martino, Maurizio; Giovannini, Maria G

    2013-01-01

    Our group recently demonstrated in a rat model that pretreatment with morphine facilitates doxorubicin delivery to the brain in the absence of signs of increased acute systemic toxicity. Morphine and other drugs such as dexamethasone or ondansetron seem to inhibit MDR proteins localized on blood-brain barrier, neurons and glial cells increasing the access of doxorubicin to the brain by efflux transporters competition. We explored the feasibility of active modification of the blood-brain barrier protection, by using morphine dexamethasone or ondansetron pretreatment, to allow doxorubicin accumulation into the brain in a rodent model. Rats were pretreated with morphine (10 mg/kg, i.p.), dexamethasone (2 mg/kg, i.p.) or ondansetron (2 mg/kg, i.p.) before injection of doxorubicin (12 mg/kg, i.p.). Quantitative analysis of doxorubicin was performed by mass spectrometry. Acute hearth and kidney damage was analyzed by measuring doxorubicin accumulation, LDH activity and malondialdehyde plasma levels. The concentration of doxorubicin was significantly higher in all brain areas of rats pretreated with morphine (P < 0.001) or ondansetron (P < 0.05) than in control tissues. The concentration of doxorubicin was significantly higher in cerebral hemispheres and brainstem (P < 0.05) but not in cerebellum of rats pretreated with dexamethasone than in control tissues. Pretreatment with any of these drugs did not increase LDH activity or lipid peroxidation compared to controls. Our data suggest that morphine, dexamethasone or ondansetron pretreatment is able to allow doxorubicin penetration inside the brain by modulating the BBB. This effect is not associated with acute cardiac or renal toxicity. This finding might provide the rationale for clinical applications in the treatment of refractory brain tumors and pave the way to novel applications of active but currently inapplicable chemotherapeutic drugs. PMID:23977451

  1. Side by side comparison between dynamic versus static models of blood-brain barrier in vitro: a permeability study.

    Science.gov (United States)

    Santaguida, Stefano; Janigro, Damir; Hossain, Mohammed; Oby, Emily; Rapp, Edward; Cucullo, Luca

    2006-09-13

    Endothelial cells in vivo are continuously exposed to shear stress, a tangential force generated by the flow of blood across their apical surfaces that affects endothelial cell structure and function. By contrast, the Transwell apparatus cannot reproduce the presence of intraluminal blood flow that is essential for the formation and differentiation of the BBB. In contrast, the dynamic in vitro model of the BBB (DIV-BBB) mimics both functionally and anatomically the brain microvasculature, creating quasi-physiological conditions for co-culturing human and non-human endothelial cells and astrocytes in a capillary-like structure. We used intraluminal bovine aortic endothelial cells (BAEC) co-cultured with extraluminal glial cells (C6) to obtain elevated trans-endothelial electrical resistance (TEER) and selective permeability to sucrose and phenytoin. The experiments were performed in parallel using Transwell systems DIV-BBB models and data were then cross compared. By contrast with Transwell, C6 and BAEC co-cultured in the DIV-BBB demonstrated predominantly aerobic metabolism evidenced by a robust increase in glucose consumption that was paralleled by a similar change in lactate production. BAEC exposed to glia under dynamic conditions grow in a monolayer fashion and developed a more stringent barrier as demonstrated by high TEER values and a selective permeability to [14C] phenytoin and the well-known paracellular marker [3H] sucrose. In conclusion, these data demonstrate that the exposure to intraluminal flow plays an essential role in promoting endothelial cell differentiation and increasing BBB tightness, thus making the use of the DIV-BBB well suited for pharmacological studies.

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

    Directory of Open Access Journals (Sweden)

    Zijuan Zhou

    2017-11-01

    Full Text Available 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.

  3. Altered intestinal microbial flora and impaired epithelial barrier structure and function in CKD: the nature, mechanisms, consequences and potential treatment.

    Science.gov (United States)

    Vaziri, Nosratola D; Zhao, Ying-Yong; Pahl, Madeleine V

    2016-05-01

    Chronic kidney disease (CKD) results in systemic inflammation and oxidative stress which play a central role in CKD progression and its adverse consequences. Although many of the causes and consequences of oxidative stress and inflammation in CKD have been extensively explored, little attention had been paid to the intestine and its microbial flora as a potential source of these problems. Our recent studies have revealed significant disruption of the colonic, ileal, jejunal and gastric epithelial tight junction in different models of CKD in rats. Moreover, the disruption of the epithelial barrier structure and function found in uremic animals was replicated in cultured human colonocytes exposed to uremic human plasma in vitro We have further found significant changes in the composition and function of colonic bacterial flora in humans and animals with advanced CKD. Together, uremia-induced impairment of the intestinal epithelial barrier structure and function and changes in composition of the gut microbiome contribute to the systemic inflammation and uremic toxicity by accommodating the translocation of endotoxin, microbial fragments and other noxious luminal products in the circulation. In addition, colonic bacteria are the main source of several well-known pro-inflammatory uremic toxins such as indoxyl sulfate, p-cresol sulfate, trimethylamine-N-oxide and many as-yet unidentified retained compounds in end-stage renal disease patients. This review is intended to provide an overview of the effects of CKD on the gut microbiome and intestinal epithelial barrier structure and their role in the pathogenesis of systemic inflammation and uremic toxicity. In addition, potential interventions aimed at mitigating these abnormalities are briefly discussed. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  4. Adrenaline increases blood-brain-barrier permeability after haemorrhagic cardiac arrest in immature pigs.

    Science.gov (United States)

    Semenas, E; Sharma, H S; Wiklund, L

    2014-05-01

    Adrenaline (ADR) and vasopressin (VAS) are used as vasopressors during cardiopulmonary resuscitation. Data regarding their effects on blood-brain barrier (BBB) integrity and neuronal damage are lacking. We hypothesised that VAS given during cardiopulmonary resuscitation (CPR) after haemorrhagic circulatory arrest will preserve BBB integrity better than ADR. Twenty-one anaesthetised sexually immature male piglets (with a weight of 24.3 ± 1.3 kg) were bled 35% via femoral artery to a mean arterial blood pressure of 25 mmHg in the period of 15 min. Afterwards, the piglets were subjected to 8 min of untreated ventricular fibrillation followed by 15 min of open-chest CPR. At 9 min of circulatory arrest, piglets received amiodarone 1.0 mg/kg and hypertonic-hyperoncotic solution 4 ml/kg infusions for 20 min. At the same time, VAS 0.4 U/kg was given intravenously to the VAS group (n = 9) while the ADR group received ADR 20 μg/kg (n = 12). Internal defibrillation was attempted from 11 min of cardiac arrest to achieve restoration of spontaneous circulation. The experiment was terminated 3 h after resuscitation. The intracranial pressure (ICP) in the post-resuscitation phase was significantly greater in ADR group than in VAS group. VAS group piglets exhibited a significantly smaller BBB disruption compared with ADR group. Cerebral pressure reactivity index showed that cerebral blood flow autoregulation was also better preserved in VAS group. Resuscitation with ADR as compared with VAS after haemorrhagic circulatory arrest increased the ICP and impaired cerebrovascular autoregulation more profoundly, as well as exerted an increased BBB disruption though no significant difference in neuronal injury was observed. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  5. Effect of chemical permeation enhancers on stratum corneum barrier lipid organizational structure and interferon alpha permeability.

    Science.gov (United States)

    Moghadam, Shadi H; Saliaj, Evi; Wettig, Shawn D; Dong, Chilbert; Ivanova, Marina V; Huzil, J Torin; Foldvari, Marianna

    2013-06-03

    The outermost layer of the skin, known as the stratum corneum (SC), is composed of dead corneocytes embedded in an intercellular lipid matrix consisting of ceramides, free fatty acids, and cholesterol. The high level of organization within this matrix protects the body by limiting the permeation of most compounds through the skin. While essential for its protective functions, the SC poses a significant barrier for the delivery of topically applied pharmaceutical agents. Chemical permeation enhancers (CPEs) can increase delivery of small drug compounds into the skin by interacting with the intercellular lipids through physical processes including extraction, fluidization, increased disorder, and phase separation. However, it is not clear whether these same mechanisms are involved in delivery of biotherapeutic macromolecules, such as proteins. Here we describe the effect of three categories of CPEs {solvents [ethanol, propylene glycol, diethylene glycol monoethyl ether (transcutol), oleic acid], terpenes [menthol, nerol, camphor, methyl salicylate], and surfactants [Tween 80, SDS, benzalkonium chloride, polyoxyl 40 hydrogenated castor oil (Cremophor RH40), didecyldimethylammonium bromide (DDAB), didecyltrimethylammonium bromide (DTAB)]} on the lipid organizational structure of human SC as determined by X-ray scattering studies. Small- and wide-angle X-ray scattering studies were conducted to correlate the degree of structural changes and hydrocarbon chain packing in SC lipids caused by these various classes of CPEs to the extent of permeation of interferon alpha-2b (IFNα), a 19 kDa protein drug, into human skin. With the exception of solvents, propylene glycol and ethanol, all classes of CPEs caused increased disordering of lamellar and lateral packing of lipids. We observed that the highest degree of SC lipid disordering was caused by surfactants (especially SDS, DDAB, and DTAB) followed by terpenes, such as nerol. Interestingly, in vitro skin permeation studies

  6. Novel effects of the prototype translocating Escherichia coli, strain C25 on intestinal epithelial structure and barrier function.

    Science.gov (United States)

    Zareie, Mehri; Riff, Jason; Donato, Kevin; McKay, Derek M; Perdue, Mary H; Soderholm, Johan D; Karmali, Mohamed; Cohen, Mitchell B; Hawkins, Jennifer; Sherman, Philip M

    2005-12-01

    Intestinal bacteria play an etiologic role in triggering and perpetuating chronic inflammatory bowel disorders. However, the precise mechanisms whereby the gut microflora influences intestinal cell function remain undefined. Therefore, the effects of the non-pathogenic prototype translocating Escherichia coli, strain C25 on the barrier properties of human T84 and Madine-Darby canine kidney type 1 epithelial cells were examined. T-84 cells were also infected with commensal E. coil, strains F18 and HB101, and enterohaemorrhagic E. coli, serotype O157:H7. Strains F18 and HB101 had no effect on transepithelial electrical resistance (TER) of T84 monolayers. By contrast, epithelial cells infected with strain C25 displayed a time-dependent decrease in TER, preceded by an altered distribution of the cytoskeletal protein alpha-actinin, comparable to infection with E. coli O157:H7. E. coli C25 infection also led to activation of nuclear factor kappaB (NF-kappaB), interleukin-8 secretion and alterations in localization of claudin-1, but not zona occludens-1 or claudin-4, in T84 cells. There were adherent C25 bacteria on the intact apical surface of infected T84 cells, while mitochondria appeared swollen and vacuolated. These novel findings demonstrate the ability of a translocating commensal bacterium to adhere to and modulate intestinal epithelial barrier function and to induce morphological changes in a manner distinct from the known enteric pathogen, E. coli O157:H7.

  7. A new PAMPA model using an in-house brain lipid extract for screening the blood-brain barrier permeability of drug candidates.

    Science.gov (United States)

    Bicker, Joana; Alves, Gilberto; Fortuna, Ana; Soares-da-Silva, Patrício; Falcão, Amílcar

    2016-03-30

    The determination of the permeability of drug candidates across the blood-brain barrier (BBB) is a fundamental step during drug discovery programs. The parallel artificial membrane permeability assay (PAMPA) is a high throughput screening tool applied to evaluate the passive permeability and adapted to predict BBB penetration. Herein, a new PAMPA model was developed using an in-house brain lipid extract capable of discriminating BBB permeable from non-permeable compounds. The apparent permeability (Papp) of 18 reference molecules and 10 test compounds was assessed and compared with phosphatidylcholine and commercial porcine polar brain lipid (PBL). The physicochemical selectivity of the in-house brain lipid extract was demonstrated by correlating Papp values with physicochemical properties and its predictive capacity estimated by establishing in vitro-in vivo correlations. The strong correlations achieved between 2% (w/v) in-house lipid extract and PBL for reference (r(2)=0.77) and test compounds (r(2)=0.94) support an equivalent discriminatory capacity and validate the presented model. Moreover, PAMPA studies performed with PBL and in-house lipid extract exhibited a higher correlation with the in vivo parameter logBB (r(2)=0.76 and r(2)=0.72, respectively) than phosphatidylcholine (r(2)=0.51). Overall, the applied lipid extraction process was reproducible, economical and provided lipid extracts that can be used to reliably assess BBB permeation. Copyright © 2016. Published by Elsevier B.V.

  8. Influence of dissolved inorganic carbon and calcium on gas formation and accumulation in iron permeable reactive barriers.

    Science.gov (United States)

    Ruhl, Aki S; Weber, Anne; Jekel, Martin

    2012-11-01

    Uncertainties in long-term reactivity and gas accumulation in Fe(0) permeable reactive barriers still hinder a broad application of this groundwater remediation technology. In this study long-term column experiments were conducted under varying geochemical conditions. Generation of hydrogen by anaerobic corrosion in Fe(0) reactive filters was mainly influenced by the mass flux of dissolved inorganic carbon. Both increased concentrations and volume flows led to a substantial rise in gas generation but only to slight differences of gas accumulation within the pores of the reactive filter. Comparisons of columns with different lengths showed higher averaged corrosion rates in the shorter and lower corrosion rates in the longer columns. Calcium in conjunction with dissolved inorganic carbon formed compact and localized aragonite minerals, while in the absence of calcium chukanovite dominated, which covered and passivated the reactive surface to a higher extent. Magnetite was the major crystalline corrosion product in the absence of carbonate and no decline in long term corrosion rates was observed within up to 700 days of operation. Total gas yields of columns were restricted by passivation and approached a volume of approximately 13.5 mL/g granulated cast iron. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Formation of ferrihydrite and associated iron corrosion products in permeable reactive barriers of zero-valent iron

    Science.gov (United States)

    Furukawa, Yoko; Kim, Jin-Wook; Watkins, Janet; Wilkin, Richard T.

    2002-01-01

    Ferrihydrite, which is known to form in the presence of oxygen and to be stabilized by the adsorption of Si, PO4 and SO4, is ubiquitous in the fine-grained fractions of permeable reactive barrier (PRB) samples from the U.S. Coast Guard Support Center (Elizabeth City, NC) and the Denver Federal Center (Lakewood, CO) studied by high-resolution transmission electron microscopy and selected area electron diffraction. The concurrent energy-dispersive X-ray data indicate a strong association between ferrihydrite and metals such as Si, Ca, and Cr. Magnetite, green rust 1, aragonite, calcite, mackinawite, greigite and lepidocrocite were also present, indicative of a geochemical environment that is temporally and spatially heterogeneous. Whereas magnetite, which is known to form due to anaerobic Fe0 corrosion, passivates the Fe0 surface, ferrihydrite precipitation occurs away from the immediate Fe0 surface, forming small (<0.1 microm) discrete clusters. Consequently, Fe0-PRBs may remain effective for a longer period of time in slightly oxidized groundwater systems where ferrihydrite formation occurs compared to oxygen-depleted systems where magnetite passivation occurs. The ubiquitous presence of ferrihydrite suggests that the use of Fe0-PRBs may be extended to applications that require contaminant adsorption rather than, or in addition to, redox-promoted contaminant degradation.

  10. Enhanced remediation of Cr(VI)-contaminated soil by incorporating a calcined-hydrotalcite-based permeable reactive barrier with electrokinetics.

    Science.gov (United States)

    Zhang, Jia; Xu, Yunfeng; Li, Wentao; Zhou, Jizhi; Zhao, Jun; Qian, Guangren; Xu, Zhi Ping

    2012-11-15

    This paper describes the enhanced Cr(VI)-contaminated soil remediation via a combination of electrokinetics (EK) with a calcined-hydrotalcite-based permeable reactive barrier (PRB). First, this combination proved to be feasible, and remarkably facilitated Cr(VI) remediation in a column test. Then, lightly-to-severely (0.16-1.65 mg/g) Cr(VI)-contaminated soil was remediated in a simulated test with the calcined hydrotalcite as the PRB under an voltage of 10-30 V (i.e. an electric field intensity of 0.7-2.0 V/cm). The observations demonstrated that both PRB and EK are critical to efficient remediation and the high de-contamination efficiency is supposedly attributed to the synergistic effect, for which EK concentrates anionic chromate to the anode region and PRB media (calcined hydrotalcite) absorbs and immobilizes it. Thus we have shown that the combined PRB-EK system is highly adaptive and effective in remediation of a larger area contaminated with chromate and various anionic pollutants. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Column test-based optimization of the permeable reactive barrier (PRB) technique for remediating groundwater contaminated by landfill leachates

    Science.gov (United States)

    Zhou, Dan; Li, Yan; Zhang, Yinbo; Zhang, Chang; Li, Xiongfei; Chen, Zhiliang; Huang, Junyi; Li, Xia; Flores, Giancarlo; Kamon, Masashi

    2014-11-01

    We investigated the optimum composition of permeable reactive barrier (PRB) materials for remediating groundwater heavily contaminated by landfill leachate, in column tests using various mixtures of zero-valent iron (ZVI), zeolite (Zeo) and activated carbon (AC) with 0.01-0.25, 3.0-5.0 and 0.7-1.0 mm grain sizes, respectively. The main contributors to the removal of organic/inorganic contaminants were ZVI and AC, and the optimum weight ratio of the three PRB materials for removing the contaminants and maintaining adequate hydraulic conductivity was found to be 5:1:4. Average reductions in chemical oxygen demand (COD) and contents of total nitrogen (TN), ammonium, Ni, Pb and 16 polycyclic aromatic hydrocarbons (PAHs) from test samples using this mixture were 55.8%, 70.8%, 89.2%, 70.7%, 92.7% and 94.2%, respectively. We also developed a systematic method for estimating the minimum required thickness and longevity of the PRB materials. A ≥ 309.6 cm layer with the optimum composition is needed for satisfactory longevity, defined here as meeting the Grade III criteria (the Chinese National Bureau of Standards: GB/T14848/93) for in situ treatment of the sampled groundwater for ≥ 10 years.

  12. Biological permeable reactive barriers coupled with electrokinetic soil flushing for the treatment of diesel-polluted clay soil.

    Science.gov (United States)

    Mena, Esperanza; Ruiz, Clara; Villaseñor, José; Rodrigo, Manuel A; Cañizares, Pablo

    2015-01-01

    Removal of diesel from spiked kaolin has been studied in the laboratory using coupled electrokinetic soil flushing (EKSF) and bioremediation through an innovative biological permeable reactive barriers (Bio-PRBs) positioned between electrode wells. The results show that this technology is efficient in the removal of pollutants and allows the soil to maintain the appropriate conditions for microorganism growth in terms of pH, temperature, and nutrients. At the same time, EKSF was demonstrated to be a very interesting technology for transporting pollutants, microorganisms and nutrients, although results indicate that careful management is necessary to avoid the depletion of nutrients, which are effectively transported by electro-migration. After two weeks of operation, 30% of pollutants are removed and energy consumption is under 70 kWh m(-3). Main fluxes (electroosmosis and evaporation) and changes in the most relevant parameters (nutrients, diesel, microorganisms, surfactants, moisture conductivity and pH) during treatment and in a complete post-study analysis are studied to give a comprehensive description of the most relevant processes occurring in the soil (pollutant transport and biodegradation). Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Microbial and mineral evolution in zero valent iron-based permeable reactive barriers during long-term operations.

    Science.gov (United States)

    Kumar, Naresh; Millot, Romain; Battaglia-Brunet, Fabienne; Omoregie, Enoma; Chaurand, Perrine; Borschneck, Daniel; Bastiaens, Leen; Rose, Jérôme

    2016-03-01

    Impacts of subsurface biogeochemical processes over time have always been a concern for the long-term performance of zero valent iron (Fe(0))-based permeable reactive barriers (PRBs). To evaluate the biogeochemical impacts, laboratory experiments were performed using flow-through glass columns for 210 days at controlled temperature (20 °C). Two different particle sizes of Fe(0) were used in the columns, and to simulate indigenous microbial activity, extra carbon source was provided in the two columns (biotic columns) and the remaining two columns were kept abiotic using gamma radiations. Heavy metals (Zn, As) were removed efficiently in all the columns, and no exhaustion of treatment capability or clogging was observed during our experimental duration. Newly formed Fe mineral phases and precipitates were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), and micro-XRF techniques in solid phase at the end of the experiment. In addition, 16S rRNA gene extraction was used for microbial community identification in biotic columns. During the incubation, microbial population shifted in favor of Desulfosporosinus species (sulfate-reducing bacteria) from initial dominance of Acidithiobacillus ferrooxidans in sediments. Dominant mineral phases detected in biotic columns were mackinawite (FeS) and sulfate green rust, while in abiotic columns, magnetite/maghemite phases were more prevalent.

  14. Assessing degradation rates of chlorinated ethylenes in column experiments with commercial iron materials used in permeable reactive barriers.

    Science.gov (United States)

    Ebert, Markus; Köber, Ralf; Parbs, Anika; Plagentz, Volkmar; Schäfer, Dirk; Dahmke, Andreas

    2006-03-15

    Multiple column experiments were performed using two commercial iron materials to evaluate the necessity and usefulness of preliminary investigations in permeable reactive barrier (PRB) design for chlorinated organics. Experiments were performed with contaminated groundwater and involved fresh iron granules or altered iron material excavated from PRBs. The determination of first-order rate coefficients by global nonlinear least-squares fittings indicated a variability in rate coefficients on 1 or 2 orders of magnitude. Geometric mean values of surface area normalized rate coefficients (in 10(-5) L m(-2) h(-1)) for fresh gray cast iron and iron sponge, respectively, are: tetrachloroethene (4.5, 2.6), trichloroethene (8.1, 3.3), cis-1,2-dichloroethene (3.1, 2.9), trans-1,2-dichloroethene (9.5, 5.3), 1,1-dichloroethene (4.0, 4.4), and vinyl chloride (1.6, 6.1). The increasing rate coefficients with decreasing grade of chlorination, which characterize degradation at iron sponge are linearly related to diffusion coefficients in water, suggesting diffusion limitation in the degradation process for this particular material, possibly due to a high inner surface. The variability in rate coefficients seems to be too high to use mean rate coefficients from published studies in the design procedure of PRBs, and variabilities cannot be related to groundwater characteristics, waterflow through the reactive cells, or secondary corrosion reactions.

  15. Environmental life cycle assessment of permeable reactive barriers: effects of construction methods, reactive materials and groundwater constituents.

    Science.gov (United States)

    Mak, Mark S H; Lo, Irene M C

    2011-12-01

    The effects of the construction methods, materials of reactive media and groundwater constituents on the environmental impacts of a permeable reactive barrier (PRB) were evaluated using life cycle assessment (LCA). The PRB is assumed to be installed at a simulated site contaminated by either Cr(VI) alone or Cr(VI) and As(V). Results show that the trench-based construction method can reduce the environmental impacts of the remediation remarkably compared to the caisson-based method due to less construction material consumption by the funnel. Compared to using the zerovalent iron (Fe(0)) and quartz sand mixture, the use of the Fe(0) and iron oxide-coated sand (IOCS) mixture can reduce the environmental impacts. In the presence of natural organic matter (NOM) in groundwater, the environmental impacts generated by the reactive media were significantly increased because of the higher usage of Fe(0). The environmental impacts are lower by using the Fe(0) and IOCS mixture in the groundwater with NOM, compared with using the Fe(0) and quartz sand mixture. Since IOCS can enhance the removal efficiency of Cr(VI) and As(V), the usage of the Fe(0) can be reduced, which in turn reduces the impacts induced by the reactive media.

  16. Reactive Transport Modeling for Mobilization of Arsenic in a Sediment Downgradient from an Iron Permeable Reactive Barrier

    Directory of Open Access Journals (Sweden)

    Sung-Wook Jeen

    2017-11-01

    Full Text Available Arsenic (As can be naturally present in the native aquifer materials and can be released to groundwater through reduction dissolution of iron oxides containing As. While granular iron permeable reactive barriers (PRBs can be effective for the treatment of arsenic in groundwater, the mobilization of arsenic in the sediment downgradient of the PRB might be an issue due to the reduced geochemical conditions generated by reactions in the PRB. The release of arsenic in the sediment downgradient from a proposed iron PRB was studied through laboratory column experiments and reactive transport modeling. The laboratory column experiments showed a significant removal of arsenic from the groundwater by granular iron (from the influent concentration of about 0.7 mg L−1 to less than 0.006 mg L−1 at the effluent; however, arsenic can be flushed out from the aquifer sediments (up to 0.09 mg L−1. The reactive transport modeling based on the geochemical reactions as suggested from the experiments, i.e., reductive dissolution of As-bearing goethite, was successful to reproduce the observed geochemical trends in the column experiments. This study can provide implications regarding the installation of iron PRBs to treat arsenic in groundwater and also be useful to understand geochemical behavior of arsenic under reduced conditions.

  17. Performance of iron filings and activated sludge as media for permeable reactive barriers to treat zinc contaminated groundwater

    Directory of Open Access Journals (Sweden)

    Chayapat Hassapak

    2015-02-01

    Full Text Available Zinc is one of the important contaminants in groundwater. Removal of zinc by iron filings, activated sludge and lateritic soil was studied with batch test. The lowest optimum pH for removal of zinc by iron filings, activated sludge and lateritic soil was 6. From isotherm studies iron filings and activated sludge were chosen as media for permeable reactive barrier (PRB. The PRB of 0.5-m thick was simulated in the unconfined aquifer with the distance of 21.5 m downgradient of the zinc contaminated site having constant concentration of 100 mg/l. The groundwater flow in the site was induced by the hydraulic gradient of 0.02. Simulation results indicated that the concentration of zinc of treated groundwater was less than 5 mg/l, which met Thai Groundwater Quality Standard for Drinking Purposes. The continuous PRBs using iron filings and activated sludge could treat zinc for 2,170 and 2,248 days, respectively

  18. Formation of ferrihydrite and associated iron corrosion products in permeable reactive barriers of zero-valent iron.

    Science.gov (United States)

    Furukawa, Yoko; Kim, Jin-Wook; Watkins, Janet; Wilkin, Richard T

    2002-12-15

    Ferrihydrite, which is known to form in the presence of oxygen and to be stabilized by the adsorption of Si, PO4 and SO4, is ubiquitous in the fine-grained fractions of permeable reactive barrier (PRB) samples from the U.S. Coast Guard Support Center (Elizabeth City, NC) and the Denver Federal Center (Lakewood, CO) studied by high-resolution transmission electron microscopy and selected area electron diffraction. The concurrent energy-dispersive X-ray data indicate a strong association between ferrihydrite and metals such as Si, Ca, and Cr. Magnetite, green rust 1, aragonite, calcite, mackinawite, greigite and lepidocrocite were also present, indicative of a geochemical environment that is temporally and spatially heterogeneous. Whereas magnetite, which is known to form due to anaerobic Fe0 corrosion, passivates the Fe0 surface, ferrihydrite precipitation occurs away from the immediate Fe0 surface, forming small (<0.1 microm) discrete clusters. Consequently, Fe0-PRBs may remain effective for a longer period of time in slightly oxidized groundwater systems where ferrihydrite formation occurs compared to oxygen-depleted systems where magnetite passivation occurs. The ubiquitous presence of ferrihydrite suggests that the use of Fe0-PRBs may be extended to applications that require contaminant adsorption rather than, or in addition to, redox-promoted contaminant degradation.

  19. Regulation of intestinal permeability: The role of proteases.

    Science.gov (United States)

    Van Spaendonk, Hanne; Ceuleers, Hannah; Witters, Leonie; Patteet, Eveline; Joossens, Jurgen; Augustyns, Koen; Lambeir, Anne-Marie; De Meester, Ingrid; De Man, Joris G; De Winter, Benedicte Y

    2017-03-28

    The gastrointestinal barrier is - with approximately 400 m 2 - the human body's largest surface separating the external environment from the internal milieu. This barrier serves a dual function: permitting the absorption of nutrients, water and electrolytes on the one hand, while limiting host contact with noxious luminal antigens on the other hand. To maintain this selective barrier, junction protein complexes seal the intercellular space between adjacent epithelial cells and regulate the paracellular transport. Increased intestinal permeability is associated with and suggested as a player in the pathophysiology of various gastrointestinal and extra-intestinal diseases such as inflammatory bowel disease, celiac disease and type 1 diabetes. The gastrointestinal tract is exposed to high levels of endogenous and exogenous proteases, both in the lumen and in the mucosa. There is increasing evidence to suggest that a dysregulation of the protease/antiprotease balance in the gut contributes to epithelial damage and increased permeability. Excessive proteolysis leads to direct cleavage of intercellular junction proteins, or to opening of the junction proteins via activation of protease activated receptors. In addition, proteases regulate the activity and availability of cytokines and growth factors, which are also known modulators of intestinal permeability. This review aims at outlining the mechanisms by which proteases alter the intestinal permeability. More knowledge on the role of proteases in mucosal homeostasis and gastrointestinal barrier function will definitely contribute to the identification of new therapeutic targets for permeability-related diseases.

  20. 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.

  1. Autonomous immunity in mucosal epithelial cells: fortifying the barrier against infection.

    Science.gov (United States)

    Ross, Karen F; Herzberg, Mark C

    2016-06-01

    Mucosal epithelial cells express an autonomous innate immune response that controls the overgrowth of invaded bacteria, mitigates the harmful effects of the bacteria carried within, and does not rely on other external arms of the immune response. Epithelial cell autonomous innate immunity "respects" the social biology of invading bacteria to achieve symbiosis, and is the primary protective mechanism against pathogens. Published by Elsevier Masson SAS.

  2. 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

    ), 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......BACKGROUND: Traumatic brain injury causes a disruption of the vascular endothelial glycocalyx layer that is associated with an overactivation of the sympathoadrenal system. We hypothesized that early and unselective beta-blockade with propranolol alone or in combination with the alfa2-agonist...

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

    Directory of Open Access Journals (Sweden)

    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

  4. 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.

  5. Hydraulic and geochemical performance of a permeable reactive barrier containing zero-valent iron, Denver Federal Center

    Science.gov (United States)

    McMahon, P.B.; Dennehy, K.F.; Sandstrom, M.W.

    1999-01-01

    The hydraulic and geochemical performance of a 366 m long permeable reactive barrier (PRB) at the Denver Federal Center; Denver, Colorado, was evaluated. The funnel and gate system, which was installed in 1996 to intercept and remediate ground water contaminated with chlorinated aliphatic hydrocarbons (CAHs), contained four 12.2 m wide gates filled with zero-valent iron. Ground water mounding on the upgradient side of the PRB resulted in a tenfold increase in the hydraulic gradient and ground water velocity through the gates compared to areas of the aquifer unaffected by the PRB. Water balance calculations for April 1997 indicate that about 75% of the ground water moving toward the PRB from upgradient areas moved through the gates. The rest of the water either accumulated on the upgradient side of the PRB or bypassed the PRB. Chemical data from monitoring wells screened down-gradient, beneath, and at the ends of the PRB indicate that contaminants had not bypassed the PRB, except in a few isolated areas. Greater than 99% of the CAH mass entering the gates was retained by the iron. Fifty-one percent of the CAH carbon entering one gate was accounted for in dissolved C1 and C2 hydrocarbons, primarily ethane and ethene, which indicates that CAHs may adsorb to the iron prior to being dehalogenated. Treated water exiting the gates displaced contaminated ground water at a distance of at least 3 m downgradient from the PRB by the end of 1997. Measurements of dissolved inorganic ions in one gate indicate that calcite and siderite precipitation in the gate could reduce gate porosity by about 0.35% per year. Results from this study indicate that funnel and gate systems containing zero-valent iron can effectively treat ground water contaminated with CAHs. However, the hydrologic impacts of the PRB on the flow system need to be fully understood to prevent contaminants from bypassing the PRB.

  6. Risk mitigation by waste-based permeable reactive barriers for groundwater pollution control at e-waste recycling sites.

    Science.gov (United States)

    Beiyuan, Jingzi; Tsang, Daniel C W; Yip, Alex C K; Zhang, Weihua; Ok, Yong Sik; Li, Xiang-Dong

    2017-02-01

    Permeable reactive barriers (PRBs) have proved to be a promising passive treatment to control groundwater contamination and associated human health risks. This study explored the potential use of low-cost adsorbents as PRBs media and assessed their longevity and risk mitigation against leaching of acidic rainfall through an e-waste recycling site, of which Cu, Zn, and Pb were the major contaminants. Batch adsorption experiments suggested a higher adsorption capacity of inorganic industrial by-products [acid mine drainage sludge (AMDS) and coal fly ash (CFA)] and carbonaceous recycled products [food waste compost (FWC) and wood-derived biochar] compared to natural inorganic minerals (limestone and apatite). Continuous leaching tests of sand columns with 10 wt% low-cost adsorbents were then conducted to mimic the field situation of acidic rainfall infiltration through e-waste-contaminated soils (collected from Qingyuan, China) by using synthetic precipitation leaching procedure (SPLP) solution. In general, Zn leached out first, followed by Cu, and finally delayed breakthrough of Pb. In the worst-case scenario (e.g., at initial concentrations equal to 50-fold of average SPLP result), the columns with limestone, apatite, AMDS, or biochar were effective for a relatively short period of about 20-40 pore volumes of leaching, after which Cu breakthrough caused non-cancer risk concern and later-stage Pb leaching considerably increased both non-cancer and lifetime cancer risk associated with portable use of contaminated water. In contrast, the columns with CFA or FWC successfully mitigated overall risks to an acceptable level for a prolonged period of 100-200 pore volumes. Therefore, with proper selection of low-cost adsorbents (or their mixture), waste-based PRBs is a technically feasible and economically viable solution to mitigate human health risk due to contaminated groundwater at e-waste recycling sites.

  7. FeS-coated sand for removal of arsenic(III) under anaerobic conditions in permeable reactive barriers

    Science.gov (United States)

    Han, Y.-S.; Gallegos, T.J.; Demond, A.H.; Hayes, K.F.

    2011-01-01

    Iron sulfide (as mackinawite, FeS) has shown considerable promise as a material for the removal of As(III) under anoxic conditions. However, as a nanoparticulate material, synthetic FeS is not suitable for use in conventional permeable reactive barriers (PRBs). This study developed a methodology for coating a natural silica sand to produce a material of an appropriate diameter for a PRB. Aging time, pH, rinse time, and volume ratios were varied, with a maximum coating of 4.0 mg FeS/g sand achieved using a pH 5.5 solution at a 1:4 volume ratio (sand: 2 g/L FeS suspension), three days of aging and no rinsing. Comparing the mass deposited on the sand, which had a natural iron-oxide coating, with and without chemical washing showed that the iron-oxide coating was essential to the formation of a stable FeS coating. Scanning electron microscopy images of the FeS-coated sand showed a patchwise FeS surface coating. X-ray photoelectron spectroscopy showed a partial oxidation of the Fe(II) to Fe(III) during the coating process, and some oxidation of S to polysulfides. Removal of As(III) by FeS-coated sand was 30% of that by nanoparticulate FeS at pH 5 and 7. At pH 9, the relative removal was 400%, perhaps due to the natural oxide coating of the sand or a secondary mineral phase from mackinawite oxidation. Although many studies have investigated the coating of sands with iron oxides, little prior work reports coating with iron sulfides. The results suggest that a suitable PRB material for the removal of As(III) under anoxic conditions can be produced through the deposition of a coating of FeS onto natural silica sand with an iron-oxide coating. ?? 2010 Elsevier Ltd.

  8. 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.

    Science.gov (United States)

    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

  9. Type III IFNs Are Commonly Induced by Bacteria-Sensing TLRs and Reinforce Epithelial Barriers during Infection.

    Science.gov (United States)

    Odendall, Charlotte; Voak, Andrew A; Kagan, Jonathan C

    2017-11-01

    Type III IFNs (IFN-λs) are secreted factors that are well-known for their antiviral activities. However, their regulation and functions during bacterial infections are unclear. In this article, we report that the regulation of IFN-λ genes did not track with mechanisms that control type I IFN expression in response to TLRs. Whereas type I IFNs were only expressed from TLRs present on endosomes, type III IFNs could be induced by TLRs that reside at the plasma membrane and that detect various bacterial products. The mechanisms that regulate type III IFN gene expression tracked with those that promote inflammatory cytokine and chemokine expression. Importantly, rIFN-λs enhanced epithelial barriers in vitro, preventing transcellular bacteria dissemination. We therefore propose that in addition to their functions in cell-intrinsic antiviral immunity, type III IFNs protect epithelial barrier integrity, an activity that would benefit the host during any infectious encounter. Copyright © 2017 by The American Association of Immunologists, Inc.

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

    Directory of Open Access Journals (Sweden)

    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

  11. Cathelicidin-WA Improves Intestinal Epithelial Barrier Function and Enhances Host Defense against Enterohemorrhagic Escherichia coli O157:H7 Infection.

    Science.gov (United States)

    Yi, Hongbo; Hu, Wangyang; Chen, Shan; Lu, Zeqing; Wang, Yizhen

    2017-02-15

    Impaired epithelial barrier function disrupts immune homeostasis and increases inflammation in intestines, leading to many intestinal diseases. Cathelicidin peptides suppress intestinal inflammation and improve intestinal epithelial barrier function independently of their antimicrobial activity. In this study, we investigated the effects of Cathelicidin-WA (CWA) on intestinal epithelial barrier function, as well as the underlying mechanism, by using enterohemorrhagic Escherichia coli (EHEC)-infected mice and intestinal epithelial cells. The results showed that CWA attenuated EHEC-induced clinical symptoms and intestinal colitis, as did enrofloxacin (Enro). CWA decreased IL-6 production in the serum, jejunum, and colon of EHEC-infected mice. Additionally, CWA alleviated the EHEC-induced disruption of mucin-2 and goblet cells in the intestine. Interestingly, CWA increased the mucus layer thickness, which was associated with increasing expression of trefoil factor 3, in the jejunum of EHEC-infected mice. CWA increased the expression of tight junction proteins in the jejunum of EHEC-infected mice. Using intestinal epithelial cells and a Rac1 inhibitor in vitro, we demonstrated that the CWA-mediated increases in the tight junction proteins might depend on the Rac1 pathway. Furthermore, CWA improved the microbiota and short-chain fatty acid concentrations in the cecum of EHEC-infected mice. Although Enro and CWA had similar effects on intestinal inflammation, CWA was superior to Enro with regard to improving intestinal epithelial barrier and microbiota in the intestine. In conclusion, CWA attenuated EHEC-induced inflammation, intestinal epithelial barrier damage, and microbiota disruption in the intestine of mice, suggesting that CWA may be an effective therapy for many intestinal diseases. Copyright © 2017 by The American Association of Immunologists, Inc.

  12. Low uptake of silica nanoparticles in Caco-2 intestinal epithelial barriers

    NARCIS (Netherlands)

    Ye, Dong; Bramini, Mattia; Hristov, Delyan R.; Wan, Sha; Salvati, Anna; Åberg, Christoffer; Dawson, Kenneth A.

    2017-01-01

    Cellular barriers, such as the skin, the lung epithelium or the intestinal epithelium, constitute one of the first obstacles facing nanomedicines or other nanoparticles entering organisms. It is thus important to assess the capacity of nanoparticles to enter and transport across such barriers. In

  13. In vivo measurements of blood-brain barrier permeability using micro-dialysis: radiobiological application; Etude in vivo des effets de l'irradiation gamma sur la permeabilite de la barriere hemato-encephalique

    Energy Technology Data Exchange (ETDEWEB)

    Agin, A.; Diserbo, M.; Mauris, J.; Martin, C

    1998-07-01

    The effects of total-body irradiation on the permeability of striatal blood-brain barrier (BBB) to [{sup 3}H] amino-isobutyric acid (AIBA) and [{sup 14}C] sucrose were investigated. Six weeks, three and five months after gamma exposure at the dose of 4.5 Gy, no modification of the transport of AIB or of the diffusion of sucrose from blood to brain was observed. (authors)

  14. The Blood-Brain Barrier Permeability of Lignans and Malabaricones from the Seeds of Myristica fragrans in the MDCK-pHaMDR Cell Monolayer Model

    Directory of Open Access Journals (Sweden)

    Ni Wu

    2016-01-01

    Full Text Available The blood-brain barrier (BBB permeability of twelve lignans and three phenolic malabaricones from the seeds of Myristica fragrans (nutmeg were studied with the MDCK-pHaMDR cell monolayer model. The samples were measured by high-performance liquid chromatography and the apparent permeability coefficients (Papp were calculated. Among the fifteen test compounds, benzonfuran-type, dibenzylbutane-type and arylnaphthalene-type lignans showed poor to moderate permeabilities with Papp values at 10−8–10−6 cm/s; those of 8-O-4′-neolignan and tetrahydrofuran-lignan were at 10−6–10−5 cm/s, meaning that their permeabilities are moderate to high; the permeabilities of malabaricones were poor as their Papp values were at 10−8–10−7 cm/s. To 5-methoxy-dehydrodiisoeugenol (2, erythro-2-(4-allyl-2,6-dimethoxyphenoxy-1-(3,4-dimethoxyphenyl-propan-1-ol acetate (6, verrucosin (8, and nectandrin B (9, an efflux way was involved and the main transporter for 6, 8 and 9 was demonstrated to be P-glycoprotein. The time and concentration dependency experiments indicated the main transport mechanism for neolignans dehydrodiisoeugenol (1, myrislignan (7 and 8 was passive diffusion. This study summarized the relationship between the BBB permeability and structure parameters of the test compounds, which could be used to preliminarily predict the transport of a compound through BBB. The results provide a significant molecular basis for better understanding the potential central nervous system effects of nutmeg.

  15. Vascular endothelial growth factor blockade alters magnetic resonance imaging biomarkers of vascular function and decreases barrier permeability in a rat model of lung cancer brain metastasis.

    Science.gov (United States)

    Pishko, Gregory L; Muldoon, Leslie L; Pagel, Michael A; Schwartz, Daniel L; Neuwelt, Edward A

    2015-02-17

    Blockade of vascular endothelial growth factor (VEGF) to promote vascular normalization and inhibit angiogenesis has been proposed for the treatment of brain metastases; however, vascular normalization has not been well-characterized in this disease. We investigated the effect of treatment with bevacizumab anti-VEGF antibody on magnetic resonance imaging (MRI) biomarkers of brain tumor vascular characteristics in comparison to small molecule delivery in a rat model of human lung cancer brain metastasis. Athymic rats with A549 human lung adenocarcinoma intracerebral xenografts underwent MRI at 11.75 T before and one day after treatment with bevacizumab (n = 8) or saline control (n = 8) to evaluate tumor volume, free water content (edema), blood volume and vascular permeability (Ktrans). One day later, permeability to 14C-aminoisobutyric acid (AIB) was measured in tumor and brain to assess the penetration of a small drug-like molecule. In saline control animals, tumor volume, edema and permeability increased over the two day assessment period. Compared to controls, bevacizumab treatment slowed the rate of tumor growth (P = 0.003) and blocked the increase in edema (P = 0.033), but did not alter tumor blood volume. Bevacizumab also significantly reduced Ktrans (P = 0.033) and AIB passive permeability in tumor (P = 0.04), but not to peritumoral tissue or normal brain. Post-treatment Ktrans correlated with AIB levels in the bevacizumab-treated rats but not in the saline controls. The correlation of an MRI biomarker for decreased vascular permeability with decreased AIB concentration in tumor after antiangiogenic treatment suggests that bevacizumab partially restored the normal low permeability characteristics of the blood-brain barrier in a model of human lung cancer brain metastasis.

  16. Enhancing the Attenuation of Acid-Mine Drainage at Davis Mine, Rowe, Massachusetts via Installation of a Permeable Reactive Barrier.

    Science.gov (United States)

    Gillmor, A. M.; Yuretich, R. F.

    2008-12-01

    Acid Mine Drainage affects thousands of streams in the United States, sustaining the need for low-cost passive treatment options. Davis Mine, a 100 years-abandoned FeS2 mine in Western Massachusetts, is representative of the types of mines best suited for passive treatments; fairly remote, abandoned, and discharging moderately affected water (pH 100mg/L, SO42- >500mg/L) and is a good candidate for a 'starting point' of low-cost, low environmental impact remediation. We here report the shifts in pH, SO42-, and Fe following placement of reactive fill (50% CaMg(CO3)2, 25% cow manure, 25% seaweed compost) in a permeable reactive barrier placed below ground mid-way along the acidic effluent's path. Yearlong monitoring of water from 1 multi-level well (with ports in the shallow groundwater, middle groundwater, and bedrock) placed within the tailings pile over a previous year (2003-2004) showed for the three levels, respectively; pH 3.16, 4.24, and 4.04, Fe average concentrations of 4.5 mg/L, 6.5 mg/L, and 3.2 mg/L, and SO42- average concentrations of 235mg/L, 330mg/L, and 292 mg/L. One year (2007-2008) after placement of remediation mix, the three levels now average respectively; pH 4.16, 4.60, and 4.53, Fe concentrations of 0.7 mg/L, 4.8 mg/L, and 1.4 mg/L, and SO42- concentrations of 217 mg/L, 294 mg/L, and 266 mg/L. The most noticeable improvement in pH is seen in the shallow groundwater, consistent with its proximity to the reactive fill depth. Although complex microbial communities have been characterized at the site, uncertainty remains as to whether they are active in this case, and it is possible that these results may be explained solely by neutralization reactions. Results of this study indicate a good likelihood that this low environmental impact remediation could be effective.

  17. A review of the mechanisms of blood-brain barrier permeability by tissue-type plasminogen activator treatment for cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Yasuhiro eSuzuki

    2016-01-01

    Full Text Available Cerebrovascular homeostasis is maintained by the blood-brain barrier (BBB, which forms a mechanical and functional barrier between systemic circulation and the central nervous system. In patients with ischemic stroke, the recombinant tissue-type plasminogen activator (rt-PA is used to accelerate recanalization of the occluded vessels. However, rt-PA is associated with a risk of increasing intracranial bleeding. This effect is thought to be caused by the increase in cerebrovascular permeability though various factors such as ischemic reperfusion injury and the activation of matrix metalloproteinases, but the detailed mechanisms are unknown. It was recently found that rt-PA treatment enhances BBB permeability not by disrupting the BBB, but by activating the vascular endothelial growth factor (VEGF system. The VEGF regulates both the dissociation of endothelial-endothelial cell junctions and endothelial endocytosis, and causes a subsequent increase in vessel permeability through the VEGF receptor-2 activation in endothelial cells. Here, we review the possibility that rt-PA increases the penetration of toxic molecules derived from the bloodstream including rt-PA itself, without disrupting the BBB, and contributes to these detrimental processes in the cerebral parenchyma.

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

    Science.gov (United States)

    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 .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.

  19. Regulation of Tight Junction Permeability by Intestinal Bacteria and Dietary Components

    NARCIS (Netherlands)

    Ulluwishewa, D.; Anderson, R.C.; McNabb, W.C.; Moughan, P.J.; Wells, J.; Roy, N.C.

    2011-01-01

    The human intestinal epithelium is formed by a single layer of epithelial cells that separates the intestinal lumen from the underlying lamina propria. The space between these cells is sealed by tight junctions (TJ), which regulate the permeability of the intestinal barrier. TJ are complex protein

  20. Step-wise DNA methylation changes are linked to escape from defined proliferation barriers and mammary epithelial cell immortalization

    Science.gov (United States)

    Novak, P; Jensen, TJ; Garbe, JC; Stampfer, MR; Futscher, BW

    2009-01-01

    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 upon 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 may prove useful in breast cancer risk assessment. PMID:19509227

  1. Dynamic analysis of the mesenchymal-epithelial transition of blood-brain barrier forming glia in Drosophila

    Science.gov (United States)

    Schwabe, Tina; Li, Xiaoling

    2017-01-01

    ABSTRACT During development, many epithelia are formed by a mesenchymal-epithelial transition (MET). Here, we examine the major stages and underlying mechanisms of MET during blood-brain barrier formation in Drosophila. We show that contact with the basal lamina is essential for the growth of the barrier-forming subperineurial glia (SPG). Septate junctions (SJs), which provide insulation of the paracellular space, are not required for MET, but are necessary for the establishment of polarized SPG membrane compartments. In vivo time-lapse imaging reveals that the Moody GPCR signaling pathway regulates SPG cell growth and shape, with different levels of signaling causing distinct phenotypes. Timely, well-coordinated SPG growth is essential for the uniform insertion of SJs and thus the insulating function of the barrier. To our knowledge, this is the first dynamic in vivo analysis of all stages in the formation of a secondary epithelium, and of the key role trimeric G protein signaling plays in this important morphogenetic process. PMID:28108476

  2. Effect of Fusarium-Derived Metabolites on the Barrier Integrity of Differentiated Intestinal Porcine Epithelial Cells (IPEC-J2

    Directory of Open Access Journals (Sweden)

    Alexandra Springler

    2016-11-01

    Full Text Available The human, animal and plant pathogen Fusarium, which contaminates agricultural commodities worldwide, produces numerous secondary metabolites. An example is the thoroughly-investigated deoxynivalenol (DON, which severely impairs gastrointestinal barrier integrity. However, to date, the toxicological profile of other Fusarium-derived metabolites, such as enniatins, beauvericin, moniliformin, apicidin, aurofusarin, rubrofusarin, equisetin and bikaverin, are poorly characterized. Thus we examined their effects—as metabolites alone and as metabolites in combination with DON—on the intestinal barrier function of differentiated intestinal porcine epithelial cells (IPEC-J2 over 72 h. Transepithelial electrical resistance (TEER was measured at 24-h intervals, followed by evaluation of cell viability using neutral red (NR assay. Enniatins A, A1, B and B1, apicidin, aurofusarin and beauvericin significantly reduced TEER. Moniliformin, equisetin, bikaverin and rubrofusarin had no effect on TEER. In the case of apicidin, aurofusarin and beauvericin, TEER reductions were further substantiated by the addition of otherwise no-effect DON concentrations. In all cases, viability was unaffected, confirming that TEER reductions were not due to compromised viability. Considering the prevalence of mycotoxin contamination and the diseases associated with intestinal barrier disruption, consumption of contaminated food or feed may have substantial health implications.

  3. NLRP3 protects alveolar barrier integrity by an inflammasome-independent increase of epithelial cell adherence

    OpenAIRE

    Kostadinova, Elena; Chaput, Catherine; Gutbier, Birgitt; Lippmann, Juliane; Sander, Leif E.; Mitchell, Timothy J.; Suttorp, Norbert; Witzenrath, Martin; Opitz, Bastian

    2016-01-01

    Bacterial pneumonia is a major cause of acute lung injury and acute respiratory distress syndrome, characterized by alveolar barrier disruption. NLRP3 is best known for its ability to form inflammasomes and to regulate IL-1? and IL-18 production in myeloid cells. Here we show that NLRP3 protects the integrity of the alveolar barrier in a mouse model of Streptococcus pneumoniae-induced pneumonia, and ex vivo upon treatment of isolated perfused and ventilated lungs with the purified bacterial t...

  4. Effects of cadmium on intercellular junctions in a renal epithelial cell line grown on permeable membrane supports

    Energy Technology Data Exchange (ETDEWEB)

    Prozialeck, W.C.; Niewenhuis, R.J. (Philadelphia Coll. of Osteopathic Medicine, PA (United States))

    1991-03-11

    Recent findings from the authors laboratories have shown that Cd{sup 2+} has relatively specific damaging effects on adhering and occluding junctions in the established porcine renal epithelial cell line, LLC-PK{sub 1}. The present studies were undertaken in order to further characterize the junction-perturbing effects of Cd{sup 2+} in polarized monolayers of LLC-PK{sub 1} cells, and to begin to identify the mechanisms underlying these effects. LLC-PK{sub 1} cells were grown to confluency on Millicell HA chambers and exposed to Cd{sup 2+} in polarized monolayers of LLC-PK{sub 1} cells, and to begin to identify the mechanisms underlying these effects. LLC-PK{sub 1} cells were grown to confluency on Millicell HA chambers an exposed to Cd{sup 2+} by adding CdCl{sub 2} to the solutions on either side of the cell monolayer. The integrity of cell-cell junctions was assessed by monitoring the transepithelial electrical resistance. The results showed that exposure to Cd{sup 2+} caused a pronounced decrease in transepithelial resistance without causing the cells to detach from the Millicell membrane. This decrease in resistance occurred more quickly and was much more pronounced when Cd{sup 2+} was added to the basolateral surface rather than the apical surface. Furthermore, the effects of Cd{sup 2+} were greatly reduced when excess Ca{sup 2+} was present in the medium. These results suggest that Cd{sup 2+} was present in the medium. These results suggest that Cd{sup 2+} may disrupt cell-cell junctions by interacting with Ca{sup 2+} binding sites or Ca{sup 2+} channels that are oriented toward the basolateral cell surface.

  5. Non-invasive assessment of blood-brain barrier (BBB) permeability using a gamma camera to detect 99technetium-gluceptate extravasation in rat brain.

    Science.gov (United States)

    Esposito, P; Jacobson, S; Connolly, R; Gheorghe, D; Theoharides, T C

    2001-10-01

    The blood-brain barrier (BBB) is a complex structure of endothelial cells, astroglia, pericytes, and perivascular macrophages enclosed by basal lamina. The BBB regulates the entry of blood-borne molecules and cells into the brain, but it is disrupted in various inflammatory conditions of the central nervous system (CNS). We previously showed that 30 min of immobilization stress increased 99technetium-gluceptate (99Tc) extravasation, measured by a gamma counter, in brain regions containing mast cells, an effect blocked by the mast cell stabilizer disodium cromoglycate [Brain Res. 888 (2001) 117]. Here we report the use of a gamma camera to assess BBB permeability by assessing 99Tc extravasation in the rat brain, during and following acute stress, without having to sacrifice the experimental animals. This method also allows for repeated experimentation on the same animal, since the half-life of 99Tc is only 6 h, and permits testing of potential inhibitors of BBB permeability.

  6. 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...... 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...... on a pixel-by-pixel basis of cerebral perfusion, cerebral blood volume, and blood-brain barrier permeability....

  7. Magnetic resonance imaging of blood-brain barrier permeability in ischemic stroke using diffusion-weighted arterial spin labeling in rats.

    Science.gov (United States)

    Tiwari, Yash V; Lu, Jianfei; Shen, Qiang; Cerqueira, Bianca; Duong, Timothy Q

    2017-08-01

    Diffusion-weighted arterial spin labeling magnetic resonance imaging has recently been proposed to quantify the rate of water exchange (K w ) across the blood-brain barrier in humans. This study aimed to evaluate the blood-brain barrier disruption in transient (60 min) ischemic stroke using K w magnetic resonance imaging with cross-validation by dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology in the same rats. The major findings were: (i) at 90 min after stroke (30 min after reperfusion), group K w magnetic resonance imaging data showed no significant blood-brain barrier permeability changes, although a few animals showed slightly abnormal K w . Dynamic contrast-enhanced magnetic resonance imaging confirmed this finding in the same animals. (ii) At two days after stroke, K w magnetic resonance imaging revealed significant blood-brain barrier disruption. Regions with abnormal K w showed substantial overlap with regions of hyperintense T 2 (vasogenic edema) and hyperperfusion. Dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology confirmed these findings in the same animals. The K w values in the normal contralesional hemisphere and the ipsilesional ischemic core two days after stroke were: 363 ± 17 and 261 ± 18 min -1 , respectively (P magnetic resonance imaging is sensitive to blood-brain barrier permeability changes in stroke, consistent with dynamic contrast-enhanced magnetic resonance imaging and Evans blue extravasation. K w magnetic resonance imaging offers advantages over existing techniques because contrast agent is not needed and repeated measurements can be made for longitudinal monitoring or averaging.

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

    Science.gov (United States)

    Genét, Gustav Folmer; Bentzer, Peter; Hansen, Morten Bagge; Ostrowski, Sisse Rye; Johansson, Pär Ingemar

    2018-01-01

    Traumatic brain injury causes a disruption of the vascular endothelial glycocalyx layer that is associated with an overactivation of the sympathoadrenal system. We hypothesized that early and unselective beta-blockade with propranolol alone or in combination with the alfa2-agonist clonidine would decrease brain edema, blood-brain barrier permeability, and glycocalyx disruption at 24 hours after trauma. 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 motor function. We found no difference in brain water content (mean ± SD) between propranolol (80.8 ± 0.3%; 95% confidence interval [CI], 80.7-81.0) and vehicle (81.1 ± 0.6%; 95% CI, 80.8-81.4) (p = 0.668) or between propranolol/clonidine (80.8 ± 0.3%; 95% CI, 80.7-81.0) and vehicle (p = 0.555). 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. This study does not provide any support for unselective beta-blockade with propranolol or the combination of propranolol and the alfa2-agonist clonidine on brain water content. The novel finding of an increase in plasma concentrations of epinephrine and syndecan-1 after propranolol treatment in traumatic brain injury is of unclear significance and should be investigated further.

  9. 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

    -actin content in Madin–Darby canine kidney-II cells expressing Flag-claudin-5, thereby increasing the permeability to the small molecule lucifer yellow. Interestingly, zonula occludens protein 1 (ZO-1), which links transmembranous TJ proteins to the actin cytoskeleton, was not affected by caprate treatment....... Similarly, endogenous claudin-5 in the membrane of brain endothelia was displaced together with F-actin, whereas ZO-1 remained unaffected. Caprate transiently opens the paracellular space, reducing the intercellular claudin-5/claudin-5 interactions and the polymerized actin at the perijunctional region...

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

    Science.gov (United States)

    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/cm2 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/cm2 for CuO NMs, and 4.25 μg/cm2 for copper sulphate (CuSO4), which informed the selection of concentrations for further studies. The differentiation status of cells and the impact of CuO NMs and CuSO4 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 CuSO4 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 CuSO4 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 (Papp); a measure of barrier permeability to CuO NMs. For all experiments, CuSO4 was used as an ionic control. CuO NMs and CuSO4 caused a concentration dependent decrease in cell viability in undifferentiated cells. CuO NMs and CuSO4 translocated across

  11. 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

    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...

  12. Low permeability to oxygen of a new barrier film prevents butyric acid bacteria spore formation in farm corn silage.

    Science.gov (United States)

    Borreani, G; Tabacco, E

    2008-11-01

    The outgrowth of Clostridium spore-forming bacteria causes late blowing in cheeses. Recently, the role of air diffusion during storage and feed-out and the role of aerobic deterioration has been shown to indirectly favor butyric acid bacteria (BAB) growth and to determine the presence of high concentrations of BAB spores in farm tank milk. A new oxygen barrier (OB) film was tested and compared with conventional polyethylene (ST). The objective was to verify whether the OB film could prevent BAB spore formation in whole-crop corn silage during storage on 2 commercial farms with different potential silage spoilage risks. Two bunkers (farms 1 and 2) were divided into 2 parts along the length so that half the feed-out face would be covered with ST film and the other half with OB film. Plastic net bags with freshly chopped corn were buried in the upper layer and in the central part (CORE) of the bunkers. The silos were opened in summer and fed out at different removal rates (19 vs. 33 cm/d). Herbage at ensiling, silage at unloading, and silage after air exposure (6 and 15 d) were analyzed for pH, nitrate, BAB spores, yeasts, and molds. The BAB spores in herbages at ensiling were 2.84 log(10) most probable number (MPN)/g, with no differences between treatments or farms. Nitrate was below the detection limit on farm 1 and exceeded 2,300 mg/kg of fresh matter on farm 2. At unloading, the BAB spores in the ST silage on farm 1 were greater than 5 log(10) MPN/g, whereas in the CORE and the OB silages, they were approximately 2 log(10) MPN/g. The ST silage had the greatest pH (5.89), the greatest mold count (5.07 log(10) cfu/g), and the greatest difference between silage temperature and ambient temperature (dT(section-ambient)). On farm 2, the ST silage had the greatest concentration of BAB spores (2.19 log(10) MPN/g), the greatest pH (4.05), and the least nitrate concentration compared with the CORE and the OB silages. Pooled data on BAB spores collected from aerobically

  13. Effects of cadmium chloride on the paracellular barrier function of intestinal epithelial cell lines

    NARCIS (Netherlands)

    Duizer, E.; Gilde, A.J.; Versantvoort, C.H.M.; Groten, J.P.

    1999-01-01

    In the present study we characterized the functional and structural disruption of the paracellular barrier of intestinal epithelium in vitro in relation to cytotoxicity after apical Cd2+ exposure. For that purpose filter-grown Caco-2 and IEC-18 cells were apically exposed to 5 to 100 μM CdCl2 for 4

  14. 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

    (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional...

  15. Epithelial barrier: an interface for the cross-communication between gut flora and immune system.

    Science.gov (United States)

    Goto, Yoshiyuki; Kiyono, Hiroshi

    2012-01-01

    Large numbers of environmental antigens, including commensal bacteria and food-derived antigens, constitutively interact with the epithelial layer of the gastrointestinal (GI) tract. Commensal bacteria peacefully cohabit with the host GI tract and exert multiple beneficial or destructive effects on their host. Intestinal epithelial cells (IECs) constitute the first physical and immunological protective wall against invasive pathogens and a cohabitation niche for commensal bacteria. As the physiological homeostasis of IECs is maintained by multiple biological processes such as apoptosis, autophagy, and the handling of endoplasmic reticulum stress, the aberrant kinetics of these biological events, which have genetic and environmental causes, leads to the development of host intestinal pathogenesis such as inflammatory bowel disease. In addition, IECs recognize and interact with commensal bacteria and give instructions to mucosal immune cells to initiate an immunological balance between active and quiescent conditions, eventually establishing intestinal homeostasis. The mucosal immune system regulates the homeostasis of gut microbiota by producing immunological molecules such as secretory immunoglobulin A, the production of which is mediated by IECs. IECs therefore play a central role in the creation and maintenance of a physiologically and immunologically stable intestinal environment. © 2011 John Wiley & Sons A/S.

  16. 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.

  17. 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

  18. Contrasting effects of linaclotide and lubiprostone on restitution of epithelial cell barrier properties and cellular homeostasis after exposure to cell stressors.

    Science.gov (United States)

    Cuppoletti, John; Blikslager, Anthony T; Chakrabarti, Jayati; Nighot, Prashant K; Malinowska, Danuta H

    2012-05-03

    Linaclotide has been proposed as a treatment for the same gastrointestinal indications for which lubiprostone has been approved, chronic idiopathic constipation and irritable bowel syndrome with constipation. Stressors damage the epithelial cell barrier and cellular homeostasis leading to loss of these functions. Effects of active linaclotide on repair of barrier and cell function in pig jejunum after ischemia and in T84 cells after treatment with proinflammatory cytokines, interferon-γ and tumor necrosis factor-α were examined. Comparison with effects of lubiprostone, known to promote repair of barrier function was carried out. In ischemia-damaged pig jejunum, using measurements of transepithelial resistance, (3)H-mannitol fluxes, short-circuit current (Cl(-) secretion) and occludin localization, active linaclotide failed to effectively promote repair of the epithelial barrier or recovery of short-circuit current, whereas lubiprostone promoted barrier repair and increased short-circuit current. In control pig jejunum, 1 μM linaclotide and 1 μM lubiprostone both caused similar increases in short-circuit current (Cl(-) secretion). In T84 cells, using measurements of transepithelial resistance, fluxes of fluorescent macromolecules, occludin and mitochondrial membrane potential, active linaclotide was virtually ineffective against damage caused by interferon-γ and tumor necrosis factor-α, while lubiprostone protected or promoted repair of epithelial barrier and cell function. Barrier protection/repair by lubiprostone was inhibited by methadone, a ClC-2 inhibitor. Linaclotide, but not lubiprostone increased [cGMP]i as expected and [Ca(2+)]i and linaclotide depolarized while lubiprostone hyperpolarized the T84 plasma membrane potential suggesting that lubiprostone may lead to greater cellular stability compared to linaclotide. In T84 cells, as found with linaclotide but not with lubiprostone, transepithelial resistance was slightly but significantly decreased by

  19. Protein kinase C activation modulates reversible increase in cortical blood–brain barrier permeability and tight junction protein expression during hypoxia and posthypoxic reoxygenation

    Science.gov (United States)

    Willis, Colin L; Meske, Diana S; Davis, Thomas P

    2010-01-01

    Hypoxia (Hx) is a component of many disease states including stroke. Ischemic stroke occurs when there is a restriction of cerebral blood flow and oxygen to part of the brain. During the ischemic, and subsequent reperfusion phase of stroke, blood–brain barrier (BBB) integrity is lost with tight junction (TJ) protein disruption. However, the mechanisms of Hx and reoxygenation (HR)-induced loss of BBB integrity are not fully understood. We examined the role of protein kinase C (PKC) isozymes in modifying TJ protein expression in a rat model of global Hx. The Hx (6% O2) induced increased hippocampal and cortical vascular permeability to 4 and 10 kDa dextran fluorescein isothiocyanate (FITC) and endogenous rat-IgG. Cortical microvessels revealed morphologic changes in nPKC-θ distribution, increased nPKC-θ and aPKC-ζ protein expression, and activation by phosphorylation of nPKC-θ (Thr538) and aPKC-ζ (Thr410) residues after Hx treatment. Claudin-5, occludin, and ZO-1 showed disrupted organization at endothelial cell margins, whereas Western blot analysis showed increased TJ protein expression after Hx. The PKC inhibition with chelerythrine chloride (5 mg/kg intraperitoneally) attenuated Hx-induced hippocampal vascular permeability and claudin-5, PKC (θ and ζ) expression, and phosphorylation. This study supports the hypothesis that nPKC-θ and aPKC-ζ signaling mediates TJ protein disruption resulting in increased BBB permeability. PMID:20700133

  20. Melatonin attenuates the postischemic increase in blood-brain barrier permeability and decreases hemorrhagic transformation of tissue-plasminogen activator therapy following ischemic stroke in mice.

    Science.gov (United States)

    Chen, Tsung-Ying; Lee, Ming-Yang; Chen, Hung-Yi; Kuo, Yen-Liang; Lin, Shih-Chieh; Wu, Tian-Shung; Lee, E-Jian

    2006-04-01

    Melatonin protects against transient middle cerebral artery (MCA) occlusion and may be suited as an add-on therapy of tissue plasminogen activator (t-PA) thrombolysis. Herein, we examined whether melatonin would reduce postischemic increase in the blood-brain barrier (BBB) permeability and, therefore, attenuate the risk of hemorrhagic transformation after t-PA therapy in experimental stroke. Twelve mice were subjected to transient occlusion of the MCA for 1 hr, followed by 24 hr of reperfusion. Melatonin (5 mg/kg, i.p.) or vehicle was given at the beginning of reperfusion. BBB permeability was evaluated by quantitation of Evans Blue leakage. An additional 32 mice underwent photothrombotic occlusion of the distal MCA, and were administered vehicle or t-PA (10 mg/kg, i.v.), alone or in combination with melatonin (5 mg/kg, i.p.), at 6 hr postinsult. The animals were then killed after 24 hr for the determination of infarct and hemorrhage volumes. Relative to controls, melatonin-treated animals had significantly reduced BBB permeability (by 52%; P hr after photo-irradiation, either t-PA or melatonin, or a combined administration of t-PA plus melatonin, did not significantly affect brain infarction (P > 0.05), compared with controls. Mice treated with t-PA alone, however, had significantly increased hemorrhagic formation (P transformation after t-PA therapy for ischemic stroke. The findings further highlight melatonin's potential role in the field of thrombolytic treatment for ischemic stroke patients.

  1. Blood-brain barrier specific permeability assay reveals N-methylated tyramine derivatives in standardised leaf extracts and herbal products of Ginkgo biloba.

    Science.gov (United States)

    Könczöl, Árpád; Rendes, Kata; Dékány, Miklós; Müller, Judit; Riethmüller, Eszter; Balogh, György Tibor

    2016-11-30

    The linkage between the central nervous system availability and neuropharmacological activity of the constituents of Ginkgo biloba L. extracts (GBE) is still incomplete. In this study, the in vitro blood-brain barrier (BBB) permeability profile of the standardised GBE was investigated by the parallel artificial membrane permeability assay (PAMPA). Biomarkers, such as terpene trilactones, flavonoid aglycones and ginkgotoxin exerted moderate or good BBB-permeability potential (BBB+), while glycosides and biflavones were predicted as unable to pass the BBB. N-methyltyramine (NMT) and N,N-dimethyltyramine or hordenine (Hor) were identified among BBB+ compounds, while subsequent direct HRMS analysis revealed tyramine (Tyr) and N,N,N-trimethyltyramine or candicine (Can) in GBE as trace constituents. Distribution of Tyr, NMT, Hor and Can was determined by a validated ion-exchange mechanism-based liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method in G. biloba samples, such as herbal drugs and dietary supplements. The total content of the four tyramine derivatives in various GBEs ranged from 7.3 up to 6357μg/g dry extract with NMT and Hor as most abundant ones. Considering the pharmacological activities and the revealed fluctuation in the concentration of the analysed adrenergic protoalkaloids, the presented rapid LC-ESI-MS method is proposed for monitoring of the levels of Tyr, NMT, Hor and Can in G. biloba products. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Cerebrovascular dysfunction and blood-brain barrier permeability induced by oxidized LDL are prevented by apocynin and magnesium sulfate in female rats.

    Science.gov (United States)

    Schreurs, Malou P H; Cipolla, Marilyn J

    2014-01-01

    Oxidized low-density lipoprotein (oxLDL) is elevated during several neurologic conditions that involve cerebral edema formation, including severe preeclampsia and eclampsia; however, our understanding of its effect on the cerebral vasculature is limited. We hypothesized that oxLDL induced blood-brain barrier (BBB) disruption and changes in cerebrovascular reactivity occur through NADPH oxidase-derived superoxide. We also investigated the effect of MgSO₄ on oxLDL-induced changes in the cerebral vasculature as this is commonly used in preventing cerebral edema formation. Posterior cerebral arteries from female rats were perfused with 5 µg/mL oxLDL in rat serum with or without 50 µM apocynin or 16 mM MgSO₄ and BBB permeability and vascular reactivity were compared. oxLDL increased BBB permeability and decreased myogenic tone that were prevented by apocynin. oxLDL increased constriction to the nitric oxide synthase inhibitor nitro-L-arginine that was unaffected by apocynin. oxLDL enhanced dilation to the NO donor sodium nitroprusside that was prevented by apocynin. MgSO₄ prevented oxLDL-induced BBB permeability without affecting oxLDL-induced changes in myogenic tone. Thus, oxLDL seems to cause BBB disruption and vascular tone dysregulation through NADPH oxidase-derived superoxide. These results highlight oxLDL and NADPH oxidase as potentially important therapeutic targets in neurologic conditions that involve elevated oxLDL.

  3. Toxoplasma gondii Infection Promotes Epithelial Barrier Dysfunction of Caco-2 Cells

    Science.gov (United States)

    Briceño, Marisol Pallete; Nascimento, Layane Alencar Costa; Nogueira, Nathalia Pires; Barenco, Paulo Victor Czarnewski; Ferro, Eloisa Amália Vieira; Rezende-Oliveira, Karine; Goulart, Luiz Ricardo; Alves, Patrícia Terra; Barbosa, Bellisa de Freitas; Lima, Wânia Rezende; Silva, Neide Maria

    2016-01-01

    After oral infection, Toxoplasma gondii invades intestinal cells, induces breakdown of intestinal physiology and barrier functions, and causes intestinal pathology in some animal species. Although parasites’ invasion into host cells is a known phenomenon, the effects of T. gondii infection in the intestinal barrier are still not well established. To evaluate morphological and physiological modifications on the colorectal adenocarcinoma-derived Caco-2 cell line during T. gondii infection, microvilli, tight junction integrity, and transepithelial electrical resistance (TEER) were investigated under infection. It was observed that the dextran uptake (endocytosis) and distribution were smaller in infected than in noninfected Caco-2 cells. The infection leads to the partial loss of microvilli at the cell surface. Claudin-1, zonula occludens-1 (ZO-1), and occludin expressions were colocalized by immunofluorescence and presented discontinuous net patterns in infected cells. Immunoblotting analysis at 24 hr postinfection revealed decreasing expression of occludin and ZO-1 proteins, whereas claudin-1 presented similar expression level compared with noninfected cells. T. gondii decreased TEER in Caco-2 cells 24 hr after infection. Our results suggest that T. gondii infection may lead to the loss of integrity of intestinal mucosa, resulting in impaired barrier function. PMID:27370796

  4. 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.

  5. Drug delivery strategies to enhance the permeability of the blood–brain barrier for treatment of glioma

    Directory of Open Access Journals (Sweden)

    Zhang F

    2015-04-01

    Full Text Available Fang Zhang, Chun-Lei Xu, Chun-Mei Liu School of Pharmacy, National First-Class Key Discipline for Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China Abstract: Gliomas are amongst the most insidious and destructive types of brain cancer and are associated with a poor prognosis, frequent recurrences, and extremely high lethality despite combination treatment of surgery, radiotherapy, and chemotherapy. The existence of the blood–brain barrier (BBB restricts the delivery of therapeutic molecules into the brain and offers the clinical efficacy of many pharmaceuticals that have been demonstrated to be effective for other kinds of tumors. This challenge emphasizes the need to be able to deliver drugs effectively across the BBB to reach the brain parenchyma. Enhancement of the permeability of the BBB and being able to transport drugs across it has been shown to be a promising strategy to improve drug absorption and treatment efficacy. This review highlights the innovative technologies that have been introduced to enhance the permeability of the BBB and to obtain an optimal distribution and concentration of drugs in the brain to treat gliomas, such as nanotechniques, hyperthermia techniques, receptor-mediated transport, cell-penetrating peptides, and cell-mediated delivery. Keywords: glioma, blood–brain barrier, drug delivery, nanotechnology, hyperthermia, receptor-mediated transport, cell-penetrating peptides, cell-mediated delivery

  6. Effects of salidroside pretreatment on expression of tumor necrosis factor-alpha and permeability of blood brain barrier in rat model of focal cerebralischemia-reperfusion injury.

    Science.gov (United States)

    Han, Tian

    2013-02-01

    To observe changes in expression of tumor necrosis factor (TNF)-alpha and permeability of blood brain barrier after salidroside pretreatment in rats with injury induced by focal cerebralischemia-reperfusion. Forty-five male SD rats were randomly divided into three groups (n=15): control group, ischemia-reperfusion (IR) model group, and salidroside pretreatment group. Before the IR model establishment, the rats in the salidroside pretreatment group were intraperitoneally administered with salidroside at a dose of 24 mg/(kg·d) for 7 d. After 30 min post the last administration, the IR model was induced by occlusion of middle cerebral artery with a filament. After 24 h post the operation, the water content and Evens blue content in the ischemia cerebral hemisphere were determined, and the level of TNF-alpha mRNA was detected by the semi-quantitative RT-PCR. Compared with the IR model group, the salidroside pretreatment group had significantly lower (Psalidroside pretreatment alleviated the focal cerebralischemia-reperfusion injury in the rat model, possibly by decreasing the permeability of blood brain barrier, attenuating brain edema and reducing TNF-alpha expression. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  7. FIELD TEST INSTRUCTION 100-NR-2 OPERABLE UNIT DESIGN OPTIMIZATION STUDY FOR SEQUESTRATION OF SR-90 SATURATED ZONE APATITE PERMEABLE REACTIVE BARRIER EXTENSION

    Energy Technology Data Exchange (ETDEWEB)

    BOWLES NA

    2010-10-06

    The objective of this field test instruction is to provide technical guidance for aqueous injection emplacement of an extension apatite permeable reactive barrier (PRE) for the sequestration of strontium-90 (Sr-90) using a high concentration amendment formulation. These field activities will be conducted according to the guidelines established in DOE/RL-2010-29, 100-NR-2 Design Optimization Study, hereafter referred to as the DOS. The DOS supports the Federal Facility Agreement Consent Order (EPA et al., 1989), Milestone M-16-06-01, and 'Complete Construction of a Permeable Reactive Barrier at 100-N.' Injections of apatite precursor chemicals will occur at an equal distance intervals on each end of the existing PRE to extend the PRB from the existing 91 m (300 ft) to at least 274 m (900 ft). Field testing at the 100-N Area Apatite Treatability Test Site, as depicted on Figure 1, shows that the barrier is categorized by two general hydrologic conceptual models based on overall well capacity and contrast between the Hanford and Ringold hydraulic conductivities. The upstream portion of the original barrier, shown on Figure 1, is characterized by relatively low overall well specific capacity. This is estimated from well development data and a lower contrast in hydraulic conductivity between the Hanford formation and Ringold Formations. Comparison of test results from these two locations indicate that permeability contrast between the Hanford formation and Ringold Formation is significantly less over the upstream one-third of the barrier. The estimated hydraulic conductivity for the Hanford formation and Ringold Formation over the upstream portion of the barrier based on observations during emplacement of the existing 91 m (300 ft) PRB is approximately 12 and 10 m/day (39 and 32 ft/day), respectively (PNNL-17429). However, these estimates should be used as a rough guideline only, as significant variability in hydraulic conductivity is likely to be observed in

  8. The permeability of the posterior blood ocular barrier after xenon photocoagulation: a study using fluorescein labelled dextrans.

    OpenAIRE

    McNaught, E I; Foulds, W S; Johnson, N. F.

    1981-01-01

    Xenon photocoagulation burns in the rabbit fundus were studied angiographically with fluorescein labelled dextrans of molecular weights in the range 3000 to 150 000. Recent photocoagulation burns showed dye leakage to all molecular weights used. Angiograms 2 days after burns had been produced showed leakage of dextrans of molecular weights up to and including 70 000 but no leakage of dextran of 150 000 molecular weight. At 7 days after photocoagulation healed burns remained permeable to dextr...

  9. The impact of lactoferrin with different levels of metal saturation on the intestinal epithelial barrier function and mucosal inflammation.

    Science.gov (United States)

    Majka, Grzegorz; Więcek, Grażyna; Śróttek, Małgorzata; Śpiewak, Klaudyna; Brindell, Małgorzata; Koziel, Joanna; Marcinkiewicz, Janusz; Strus, Magdalena

    2016-12-01

    Translocation of bacteria, primarily Gram-negative pathogenic flora, from the intestinal lumen into the circulatory system leads to sepsis. In newborns, and especially very low birth weight infants, sepsis is a major cause of morbidity and mortality. The results of recently conducted clinical trials suggest that lactoferrin, an iron-binding protein that is abundant in mammalian colostrum and milk, may be an effective agent in preventing sepsis in newborns. However, despite numerous basic studies on lactoferrin, very little is known about how metal saturation of this protein affects a host's health. Therefore, the main objective of this study was to elucidate how iron-depleted, iron-saturated, and manganese-saturated forms of lactoferrin regulate intestinal barrier function via interactions with epithelial cells and macrophages. For these studies, a human intestinal epithelial cell line, Caco-2, was used. In this model, none of the tested lactoferrin forms induced higher levels of apoptosis or necrosis. There was also no change in the production of tight junction proteins regardless of lactoferrin metal saturation status. None of the tested forms induced a pro-inflammatory response in Caco-2 cells or in macrophages either. However, the various lactoferrin forms did effectively inhibit the pro-inflammatory response in macrophages that were activated with lipopolysaccharide with the most potent effect observed for apolactoferrin. Lactoferrin that was not bound to its cognate receptor was able to bind and neutralize lipopolysaccharide. Lactoferrin was also able to neutralize microbial-derived antigens, thereby potentially reducing their pro-inflammatory effect. Therefore, we hypothesize that lactoferrin supplementation is a relevant strategy for preventing sepsis.

  10. 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.

  11. Protective effects of ψ taraxasterol 3-O-myristate and arnidiol 3-O-myristate isolated from Calendula officinalis on epithelial intestinal barrier.

    Science.gov (United States)

    Dall'Acqua, Stefano; Catanzaro, Daniela; Cocetta, Veronica; Igl, Nadine; Ragazzi, Eugenio; Giron, Maria Cecilia; Cecconello, Laura; Montopoli, Monica

    2016-03-01

    The triterpene esters ᴪ taraxasterol-3-O-myristate (1) and arnidiol-3-O-myristate (2) were tested for their ability to protect epithelial intestinal barrier in an in vitro model. Their effects on ROS production and on trans-epithelial resistance were investigated on CaCo-2 cell monolayers both in basal and stress-induced conditions. Both compounds were able to modulate the stress damage induced by H2O2 and INFγ+TNFα, showing a potential use as model compounds for the study of new therapeutic agents for intestinal inflammations. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Epithelial adhesion molecules and the regulation of intestinal homeostasis during neutrophil transepithelial migration

    Science.gov (United States)

    Sumagin, Ronen; Parkos, Charles A

    2014-01-01

    Epithelial adhesion molecules play essential roles in regulating cellular function and maintaining mucosal tissue homeostasis. Some form epithelial junctional complexes to provide structural support for epithelial monolayers and act as a selectively permeable barrier separating luminal contents from the surrounding tissue. Others serve as docking structures for invading viruses and bacteria, while also regulating the immune response. They can either obstruct or serve as footholds for the immune cells recruited to mucosal surfaces. Currently, it is well appreciated that adhesion molecules collectively serve as environmental cue sensors and trigger signaling events to regulate epithelial function through their association with the cell cytoskeleton and various intracellular adapter proteins. Immune cells, particularly neutrophils (PMN) during transepithelial migration (TEM), can modulate adhesion molecule expression, conformation, and distribution, significantly impacting epithelial function and tissue homeostasis. This review discusses the roles of key intestinal epithelial adhesion molecules in regulating PMN trafficking and outlines the potential consequences on epithelial function. PMID:25838976

  14. HIV enteropathy and aging: gastrointestinal immunity, mucosal epithelial barrier, and microbial translocation.

    Science.gov (United States)

    Wang, Hongyin; Kotler, Donald P

    2014-07-01

    Despite decreases in morbidity and mortality as a result of antiretroviral therapy, gastrointestinal dysfunction remains common in HIV infection. Treated patients are at risk for complications of 'premature' aging, such as cardiovascular disease, osteopenia, neurocognitive decline, malignancies, and frailty. This review summarizes recent observations in this field. Mucosal CD4 lymphocytes, especially Th17 cells, are depleted in acute HIV and simian immune deficiency virus (SIV) infections, although other cell types also are affected. Reconstitution during therapy often is incomplete, especially in mucosa. Mucosal barrier function is affected by both HIV infection and aging and includes paracellular transport via tight junctions and uptake through areas of apoptosis; other factors may affect systemic antigen exposure. The resultant microbial translocation is associated with systemic immune activation in HIV and SIV infections. There is evidence of immune activation and microbial translocation in the elderly. The immune phenotypes of immunosenescence in HIV infection and aging appear similar. There are several targets for intervention; blockage of residual mucosal virus replication, preventing antigen uptake, modulating the microbiome, improving T cell recovery, combining therapies aimed at mucosal integrity, augmenting mucosal immunity, and managing traditional risk factors for premature aging in the general population. Aging may interact with HIV enteropathy to enhance microbial translocation and immune activation.

  15. Studies on the potential neurotoxic and convulsant effects of increased blood levels of quinolinic acid in rats with altered blood-brain barrier permeability

    Energy Technology Data Exchange (ETDEWEB)

    Vezzani, A.; Stasi, M.A.; Wu, H.Q.; Castiglioni, M.; Weckermann, B.; Samanin, R. (Istituto di Ricerche Farmacologiche Mario Negri, Milano (Italy))

    1989-10-01

    Intravenous injection of 450 mg/kg quinolinic acid (Quin), an endogenous kynurenine metabolite with excitotoxic properties, induced only minor electroencephalographic (EEG) modifications and no neurotoxicity in rats with a mature blood-brain barrier (BBB). BBB permeability was altered in rats by focal unilateral irradiation of the cortex (7 mm in diameter and 5 mm in depth) with protons (60 Gy, 9 Gy/min). Three days after irradiation, Evans blue dye staining showed BBB breakdown in the dorsal hippocampus of the irradiated hemisphere. No neurotoxic or convulsant effects were observed as a consequence of the radiation itself. When BBB-lesioned rats were challenged with 225 mg/kg Quin iv, epileptiform activity was observed on EEG analysis. Tonic-clonic seizures were induced by 225-450 mg/kg Quin. Light microscopic analysis showed a dose-related excitotoxic type of lesion restricted to the hippocampus ipsilateral to the irradiated side. Neuro-degeneration was prevented by local injection of 120 nmol D(-)2-amino-7-phosphonoheptanoic acid, a selective N-methyl-D-aspartate receptor antagonist. No lesions or EEG or behavioral modifications occurred after 450 mg/kg nicotinic acid, an inactive analog of Quin. The potential neurotoxic and convulsant effects of increased blood levels of Quin under conditions of altered BBB permeability are discussed.

  16. Cellular Apoptosis and Blood Brain Barrier Permeability Changes in the Pre-Incubated Chicken Embryo’s Brain by Effect of Electromagnetic Fields

    Directory of Open Access Journals (Sweden)

    Sima Kalantari

    2015-02-01

    Full Text Available Background: Electromagnetic fields (EMF have teratogenic effects during the embryonic development. In current study, histopathological and physiological effects of sinusoidal EMF on the brain were investigated. We sought to determine the apoptosis level and changes in blood brain barrier permeability in brain tissue of pre-incubated white leghorn hen eggs in the field of EMF. Materials and Methods: In this experimental study, 300 healthy, fresh, and fertilized eggs (55-65 g were divided into experimental (3 groups, N=50, control (N=75 and sham (N=75 groups. Experimental eggs (inside the coil were exposed to 3 different intensities of 1.33, 2.66 and 7.32 mT and sham groups were also located inside the same coil but with no exposure, for 24 hrs before incubation. Control, sham and experimental groups were incubated in an incubator (38±0.5ºC, 60% humidity. Brains of 14 day old chicken embryos of all groups were removed, fixed in formalin (10%, stained with H & E and TUNEL, apoptotic cells were studied under light microscope. Brains of other embryos were prepared for scanning electron microscope. By injections of Evans blue, any possible changes in brain vessels were also investigated. Results: Our results showed electromagnetic fields have toxic effects on cell organelles and cell membranes. EMF would increase the level of cellular apoptosis in the brain. They also would tear up the blood vessels. Thereafter, they would affect the permeability of blood brain barrier of exposed chicken embryos. Conclusion: These findings suggest that electromagnetic fields induce different degrees of brain damages in chicken embryos brain tissue.

  17. Apoplastic barriers effectively block oxygen permeability across outer cell layers of rice roots under deoxygenated conditions: roles of apoplastic pores and of respiration.

    Science.gov (United States)

    Kotula, Lukasz; Ranathunge, Kosala; Steudle, Ernst

    2009-12-01

    *Despite the importance of the barrier to oxygen losses of the roots of hygrophytes growing in wet environments devoid of oxygen, there are few data available on permeability coefficients for O(2) across outer root cell layers (P(OPR)) and how they may change in response to low O(2). *A gas perfusion technique was used to measure the P(OPR) of rice (Oryza sativa) plants grown in either aerated or deoxygenated solution. The contributions of the apoplast and of living cells to the overall P(OPR) were characterized either by blocking apoplastic pores with precipitates of brown Cu(2)[Fe(CN)(6)] or by killing cells with 0.1 N HCl. *Compared with that of plants from aerated hydroponics, the P(OPR) of plants grown in deoxygenated medium was smaller by an order of magnitude. Precipitates resulting from CuSO(4)/K(4)[Fe(CN)(6)] treatment only formed in plants grown in aerated solution, where they reduced the P(OPR) by 5-20%. Killing of root segments with HCl increased P(OPR) in plants grown in both conditions by 20-55%. *The results indicated that apoplastic barriers effectively restricted radial O(2) loss. The relative role of the respiratory O(2) consumption of root peripheral layers increased as P(OPR) decreased.

  18. Probiotic-derived polyphosphate enhances the epithelial barrier function and maintains intestinal homeostasis through integrin-p38 MAPK pathway.

    Directory of Open Access Journals (Sweden)

    Shuichi Segawa

    Full Text Available Probiotics exhibit beneficial effects on human health, particularly in the maintenance of intestinal homeostasis in a complex manner notwithstanding the diversity of an intestinal flora between individuals. Thus, it is highly probable that some common molecules secreted by probiotic and/or commensal bacteria contribute to the maintenance of intestinal homeostasis and protect the intestinal epithelium from injurious stimuli. To address this question, we aimed to isolate the cytoprotective compound from a lactobacillus strain, Lactobacillus brevis SBC8803 which possess the ability to induce cytoprotective heat shock proteins in mouse small intestine. L. brevis was incubated in MRS broth and the supernatant was passed through with a 0.2-µm filter. Caco2/bbe cells were treated with the culture supernatant, and HSP27 expression was evaluated by Western blotting. HSP27-inducible components were separated by ammonium sulfate precipitation, DEAE anion exchange chromatography, gel filtration, and HPLC. Finally, we identified that the HSP27-inducible fraction was polyphosphate (poly P, a simple repeated structure of phosphates, which is a common product of lactobacilli and other bacteria associated with intestinal microflora without any definitive physiological functions. Then, poly P was synthesized by poly P-synthesizing enzyme polyphosphate kinase. The synthesized poly P significantly induced HSP27 from Caco2/BBE cells. In addition, Poly P suppressed the oxidant-induced intestinal permeability in the mouse small intestine and pharmacological inhibitors of p38 MAPK and integrins counteract its protective effect. Daily intrarectal administration of poly P (10 µg improved the inflammation grade and survival rate in 4% sodium dextran sulfate-administered mice. This study, for the first time, demonstrated that poly P is the molecule responsible for maintaining intestinal barrier actions which are mediated through the intestinal integrin β1-p38 MAPK.

  19. Characterization of immortalized choroid plexus epithelial cell lines for studies of transport processes across the blood-cerebrospinal fluid barrier

    OpenAIRE

    Kläs Juliane; Wolburg Hartwig; Terasaki Tetsuya; Fricker Gert; Reichel Valeska

    2010-01-01

    Abstract Background Two rodent choroid plexus (CP) epithelial cell lines, Z310 and TR-CSFB, were compared with primary rat CP epithelial cells and intact CP tissue with respect to transport protein expression, function and tight junction (TJ) formation. Methods For expression profiles of transporters and TJ proteins, qPCR and western blot analysis were used. Uptake assays were performed to study the functional activity of transporters and TJ formation was measured by trans-epithelial electric...

  20. Assessing the Cr(VI) reduction efficiency of a permeable reactive barrier using Cr isotope measurements and 2D reactive transport modeling.

    Science.gov (United States)

    Wanner, Christoph; Zink, Sonja; Eggenberger, Urs; Mäder, Urs

    2012-04-01

    In Thun, Switzerland, a permeable reactive barrier (PRB) for Cr(VI) reduction by gray cast iron was installed in May 2008. The PRB is composed of a double array of vertical piles containing iron shavings and gravel. The aquifer in Thun is almost saturated with dissolved oxygen and the groundwater flow velocities are ca. 10-15m/day. Two years after PRB installation Cr(VI) concentrations still permanently exceed the Swiss threshold value for contaminated sites downstream of the barrier at selected localities. Groundwater δ(53/52)Cr(SRM979) measurements were used to track Cr(VI) reduction induced by the PRB. δ(53/52)Cr(SRM979) values of two samples downstream of the PRB showed a clear fractionation towards more positive values compared to four samples from the hotspot, which is clear evidence of Cr(VI) reduction induced by the PRB. Another downstream sample did not show a shift to more positive δ(53/52)Cr(SRM979) values. Because this latter location correlates with the highest downstream Cr(VI) concentration it is proposed that a part of the Cr(VI) plume is bypassing the barrier. Using a Rayleigh fractionation model a minimum present-day overall Cr(VI) reduction efficiency of ca. 15% was estimated. A series of 2D model simulations, including the fractionation of Cr isotopes, confirm that only a PRB bypass of parts of the Cr(VI) plume can lead to the observed values. Additionally, the simulations revealed that the proposed bypass occurs due to an insufficient permeability of the individual PRB piles. It is concluded that with this type of PRB a complete and long-lasting Cr(VI) reduction is extremely difficult to achieve for Cr(VI) contaminations located in nearly oxygen and calcium carbonate saturated aquifer in a regime of high groundwater velocities. Additional remediation action would limit the environmental impact and allow to reach target concentrations. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. [The influence of acute hypercapnia on the permeability of the blood-brain barrier for gentamycin under conditions of general anesthesia in rabbits].

    Science.gov (United States)

    Pakulski, C

    1998-01-01

    The aim of the work was to demonstrate whether acute hypercapnia (paCO2 > 65 mm Hg) influenced the permeability of blood-brain barrier (BBB). Twelve Chinchilla rabbits which underwent general anaesthesia were randomly divided into 2 groups. The animals were sedated with intravenous administration of pentobarbital, then were subjected to endotracheal intubation and connected to volume-controlled respirator (Zimmermann pump). Artificial ventilation using air/oxygen mixture was applied. Auricular artery, inferior caval vein and aorta were catheterized with a catheter being also placed in the lateral ventricle of the brain. General anaesthesia was supported with continuous intravenous administration of pentobarbital. To maintain normal paCO2 values, the investigation was performed under normal ventilation in control group (5 rabbits). Controlled hypoventilation was applied to achieve an increase of paCO2 in the shortest possible time in the investigated group (7 rabbits). Heart rate (HR), systolic (SAP), diastolic (DAP) and mean (MAP) arterial blood pressure, intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were continuously recorded. Gentamycin was applied as the marker of function of BBB, because it couldn't penetrate into the cerebrospinal fluid after intravenous administration under physiological conditions. BBB function in normal and significantly increased paCO2 was evaluated using gentamycin permeability indexes (QG), defined as gentamycin concentration ratio in the cerebrospinal fluid to serum gentamycin concentration in the same moment of trial. Comparative analysis of the QG index for both groups according to values achieved before the trial and after 1 and 3 hours of experiment indicates the degree of BBB damage. Non-parametric differences significance test according to Kolmogorow-Smirnow was applied for statistical verification of the results. Significance level for the trial was alpha = 0.05. None of the monitored parameters has changed in

  2. Vascular Endothelial Growth Factor Increases during Blood-Brain Barrier-Enhanced Permeability Caused by Phoneutria nigriventer Spider Venom

    Directory of Open Access Journals (Sweden)

    Monique C. P. Mendonça

    2014-01-01

    Full Text Available Phoneutria nigriventer spider accidental envenomation provokes neurotoxic manifestations, which when critical, results in epileptic-like episodes. In rats, P. nigriventer venom (PNV causes blood-brain barrier breakdown (BBBb. The PNV-induced excitotoxicity results from disturbances on Na+, K+ and Ca2+ channels and glutamate handling. The vascular endothelial growth factor (VEGF, beyond its angiogenic effect, also, interferes on synaptic physiology by affecting the same ion channels and protects neurons from excitotoxicity. However, it is unknown whether VEGF expression is altered following PNV envenomation. We found that adult and neonates rats injected with PNV showed immediate neurotoxic manifestations which paralleled with endothelial occludin, β-catenin, and laminin downregulation indicative of BBBb. In neonate rats, VEGF, VEGF mRNA, and Flt-1 receptors, glutamate decarboxylase, and calbindin-D28k increased in Purkinje neurons, while, in adult rats, the BBBb paralleled with VEGF mRNA, Flk-1, and calbindin-D28k increases and Flt-1 decreases. Statistically, the variable age had a role in such differences, which might be due to age-related unequal maturation of blood-brain barrier (BBB and thus differential cross-signaling among components of the glial neurovascular unit. The concurrent increases in the VEGF/Flt-1/Flk-1 system in the cerebellar neuron cells and the BBBb following PNV exposure might imply a cytokine modulation of neuronal excitability consequent to homeostatic perturbations induced by ion channels-acting PNV neuropeptides. Whether such modulation represents neuroprotection needs further investigation.

  3. Apical, but not basolateral, endotoxin preincubation protects alveolar epithelial cells against hydrogen peroxide-induced loss of barrier function: the role of nitric oxide synthesis.

    Science.gov (United States)

    Rose, Frank; Guthmann, Bernd; Tenenbaum, Tobias; Fink, Ludger; Ghofrani, Ardeschir; Weissmann, Norbert; König, Peter; Ermert, Leander; Dahlem, Gabriele; Haenze, Joerg; Kummer, Wolfgang; Seeger, Werner; Grimminger, Friedrich

    2002-08-01

    The influence of LPS preincubation on hydrogen peroxide (H(2)O(2))-induced loss of epithelial barrier function was investigated in rat alveolar epithelial type II cells (ATII). Both apical and basolateral H(2)O(2) administration caused a manyfold increase in transepithelial [(3)H]mannitol passage. Apical but not basolateral preincubation of ATII with LPS did not influence control barrier properties but fully abrogated the H(2)O(2)-induced leakage response. The effect of apical LPS was CD14 dependent and was accompanied by a strong up-regulation of NO synthase II mRNA and protein and NO release. Inhibition of NO by N(G)-monomethyl-L-arginine suppressed the LPS effect, whereas it was reproduced by exogenous application of gaseous NO or NO donor agents. Manipulation of the glutathione homeostasis (buthionine-(S,R)-sulfoximine) and the cGMP pathway (1H-(1,2,4)oxadiazolo[4,3-alpha]quinoxaline-1-one; zaprinast) did not interfere with the protective effect of LPS. Superoxide (O*(-)(2)) generation by ATII cells was reduced by exogenous NO and LPS preincubation. O*(-)(2) scavenging with exogenous superoxide dismutase, the intracellular superoxide dismutase analog Mn(III)tetrakis(4-benzoic acid) porphyrin, and the superoxide scavenger nitroblue tetrazolium and, in particular, hydroxyl radical scavenging with hydroxyl radical scavenger 1,3-dimethyl-thiourea inhibited the H(2)O(2)-induced epithelial leakage response. In conclusion, apical but not basolateral LPS preincubation of ATII cells provides strong protection against H(2)O(2)-induced transepithelial leakage, attributable to an up-regulation of epithelial NO synthesis. It is suggested that the LPS-induced NO formation is effective via interaction with reactive oxygen species, including superoxide and hydroxyl radicals. The polarized epithelial response to LPS may be part of the lung innate immune system, activated by inhaled endotoxin or under conditions of pneumonia.

  4. A Novel Algorithm for the Assessment of Blood-Brain Barrier Permeability Suggests That Brain Topical Application of Endothelin-1 Does Not Cause Early Opening of the Barrier in Rats

    Directory of Open Access Journals (Sweden)

    D. Jorks

    2011-01-01

    Full Text Available There are a number of different experimental methods for ex vivo assessment of blood-brain barrier (BBB opening based on Evans blue dye extravasation. However, these methods require many different steps to prepare the brain and need special equipment for quantification. We here report a novel, simple, and fast semiquantitative algorithm to assess BBB integrity ex vivo. The method is particularly suitable for cranial window experiments, since it keeps the spatial information about where the BBB opened. We validated the algorithm using sham controls and the established model of brain topical application of the bile salt dehydrocholate for early BBB disruption. We then studied spreading depolarizations in the presence and the absence of the vasoconstrictor endothelin-1 and found no evidence of early BBB opening (three-hour time window. The algorithm can be used, for example, to assess BBB permeability ex vivo in combination with dynamic in vivo studies of BBB opening.

  5. Assessment of Blood-Brain Barrier Permeability by Dynamic Contrast-Enhanced MRI in Transient Middle Cerebral Artery Occlusion Model after Localized Brain Cooling in Rats

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Soo [Department of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068 (Korea, Republic of); Lee, Seung-Koo [Department of Radiology, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Kwon, Mi Jung [Department of Pathology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068 (Korea, Republic of); Lee, Phil Hye [Department of Neurology, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Ju, Young-Su [Department of Industrial Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068 (Korea, Republic of); Yoon, Dae Young [Department of Radiology, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul 05355 (Korea, Republic of); Kim, Hye Jeong [Department of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul 07441 (Korea, Republic of); Lee, Kwan Seop [Department of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068 (Korea, Republic of)

    2016-11-01

    The purpose of this study was to evaluate the effects of localized brain cooling on blood-brain barrier (BBB) permeability following transient middle cerebral artery occlusion (tMCAO) in rats, by using dynamic contrast-enhanced (DCE)-MRI. Thirty rats were divided into 3 groups of 10 rats each: control group, localized cold-saline (20℃) infusion group, and localized warm-saline (37℃) infusion group. The left middle cerebral artery (MCA) was occluded for 1 hour in anesthetized rats, followed by 3 hours of reperfusion. In the localized saline infusion group, 6 mL of cold or warm saline was infused through the hollow filament for 10 minutes after MCA occlusion. DCE-MRI investigations were performed after 3 hours and 24 hours of reperfusion. Pharmacokinetic parameters of the extended Tofts-Kety model were calculated for each DCE-MRI. In addition, rotarod testing was performed before tMCAO, and on days 1-9 after tMCAO. Myeloperoxidase (MPO) immunohisto-chemistry was performed to identify infiltrating neutrophils associated with the inflammatory response in the rat brain. Permeability parameters showed no statistical significance between cold and warm saline infusion groups after 3-hour reperfusion 0.09 ± 0.01 min{sup -1} vs. 0.07 ± 0.02 min{sup -1}, p = 0.661 for K{sup trans}; 0.30 ± 0.05 min{sup -1} vs. 0.37 ± 0.11 min{sup -1}, p = 0.394 for kep, respectively. Behavioral testing revealed no significant difference among the three groups. However, the percentage of MPO-positive cells in the cold-saline group was significantly lower than those in the control and warm-saline groups (p < 0.05). Localized brain cooling (20℃) does not confer a benefit to inhibit the increase in BBB permeability that follows transient cerebral ischemia and reperfusion in an animal model, as compared with localized warm-saline (37℃) infusion group.

  6. Assessment of blood-brain barrier permeability by dynamic contrast-enhanced MRI in transient middle cerebral artery occlusion model after localized brain cooling in rats

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Soo; Lee, Kwan Seop; Kwon, Mi Jung; Ju, Young Su [Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang (Korea, Republic of); Lee, Seung Koo; Lee, Phil Hye [Yonsei University College of Medicine, Seoul (Korea, Republic of); Yoon, Dae Young [Dept. of Radiology, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of); Kim, Hye Jeong [Dept. of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of)

    2016-09-15

    The purpose of this study was to evaluate the effects of localized brain cooling on blood-brain barrier (BBB) permeability following transient middle cerebral artery occlusion (tMCAO) in rats, by using dynamic contrast-enhanced (DCE)-MRI. Thirty rats were divided into 3 groups of 10 rats each: control group, localized cold-saline (20 .deg. ) infusion group, and localized warm-saline (37 .deg. ) infusion group. The left middle cerebral artery (MCA) was occluded for 1 hour in anesthetized rats, followed by 3 hours of reperfusion. In the localized saline infusion group, 6 mL of cold or warm saline was infused through the hollow filament for 10 minutes after MCA occlusion. DCE-MRI investigations were performed after 3 hours and 24 hours of reperfusion. Pharmacokinetic parameters of the extended Tofts-Kety model were calculated for each DCE-MRI. In addition, rotarod testing was performed before tMCAO, and on days 1-9 after tMCAO. Myeloperoxidase (MPO) immunohisto-chemistry was performed to identify infiltrating neutrophils associated with the inflammatory response in the rat brain. Permeability parameters showed no statistical significance between cold and warm saline infusion groups after 3-hour reperfusion 0.09 ± 0.01 min{sup -1} vs. 0.07 ± 0.02 min{sup -1},p = 0.661 for K{sup trans}; 0.30 ± 0.05 min{sup -1} vs. 0.37 ± 0.11 min{sup -1},p = 0.394 for kep, respectively. Behavioral testing revealed no significant difference among the three groups. However, the percentage of MPO-positive cells in the cold-saline group was significantly lower than those in the control and warm-saline groups (p < 0.05). Localized brain cooling (20 .deg. ) does not confer a benefit to inhibit the increase in BBB permeability that follows transient cerebral ischemia and reperfusion in an animal model, as compared with localized warm-saline (37 .deg. ) infusion group.

  7. In vivo EPR pharmacokinetic evaluation of the redox status and the blood brain barrier permeability in the SOD1(G93A) ALS rat model.

    Science.gov (United States)

    Stamenković, Stefan; Pavićević, Aleksandra; Mojović, Miloš; Popović-Bijelić, Ana; Selaković, Vesna; Andjus, Pavle; Bačić, Goran

    2017-07-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder affecting the motor pathways of the central nervous system. Although a number of pathophysiological mechanisms have been described in the disease, post mortem and animal model studies indicate blood-brain barrier (BBB) disruption and elevated production of reactive oxygen species as major contributors to disease pathology. In this study, the BBB permeability and the brain tissue redox status of the SOD1(G93A) ALS rat model in the presymptomatic (preALS) and symptomatic (ALS) stages of the disease were investigated by in vivo EPR spectroscopy using three aminoxyl radicals with different cell membrane and BBB permeabilities, Tempol, 3-carbamoyl proxyl (3CP), and 3-carboxy proxyl (3CxP). Additionally, the redox status of the two brain regions previously implicated in disease pathology, brainstem and hippocampus, was investigated by spectrophotometric biochemical assays. The EPR results indicated that among the three spin probes, 3CP is the most suitable for reporting the intracellular redox status changes, as Tempol was reduced in vivo within minutes (t1/2 =2.0±0.5min), thus preventing reliable kinetic modeling, whereas 3CxP reduction kinetics gave divergent conclusions, most probably due to its membrane impermeability. It was observed that the reduction kinetics of 3CP in vivo, in the head of preALS and ALS SOD1(G93A) rats was altered compared to the controls. Pharmacokinetic modeling of 3CP reduction in vivo, revealed elevated tissue distribution and tissue reduction rate constants indicating an altered brain tissue redox status, and possibly BBB disruption in these animals. The preALS and ALS brain tissue homogenates also showed increased nitrilation, superoxide production, lipid peroxidation and manganese superoxide dismutase activity, and a decreased copper-zinc superoxide dismutase activity. The present study highlights in vivo EPR spectroscopy as a reliable tool for the investigation of

  8. Influence of blood-brain barrier permeability on O-(2-{sup 18}F-fluoroethyl)-L-tyrosine uptake in rat gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Stegmayr, Carina; Bandelow, Ulrike; Oliveira, Dennis; Lohmann, Philipp; Willuweit, Antje; Galldiks, Norbert; Luebke, Joachim H.R. [Institute of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich (Germany); Filss, Christian; Ermert, Johannes; Langen, Karl-Josef [Institute of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich (Germany); RWTH/University Hospital Aachen, Department of Nuclear Medicine and Neurology, Aachen (Germany); Shah, N. Jon [Institute of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich (Germany); RWTH/University Hospital Aachen, Department of Nuclear Medicine and Neurology, Aachen (Germany); Juelich-Aachen Research Alliance (JARA) - Section JARA-Brain, Aachen (Germany)

    2017-03-15

    O-(2-{sup 18}F-fluoroethyl)-L-tyrosine ({sup 18}F-FET) is an established tracer for the diagnosis of brain tumors with PET. This study investigates the influence of blood-brain barrier (BBB) permeability on {sup 18}F-FET uptake in two rat glioma models and one human xenograft model. F98 glioma, 9L gliosarcoma or human U87 glioblastoma cells were implanted into the striatum of 56 Fischer or RNU rats. Thereafter, animals were divided into a control group and a group receiving injections of the glucocorticoid dexamethasone (Dex). After 12-13 days of tumor growth animals received injection of Evans blue dye (EBD) to visualize BBB disturbance and underwent {sup 18}F-FET PET followed by autoradiography. Time activity curves, standardized uptake values (SUV) and Tumor-to-brain ratios (TBR) of {sup 18}F-FET uptake [18-61 min post injection (p.i.)] were evaluated using a volume-of-Interest (VOI) analysis. BBB disturbance was quantitatively evaluated by EBD fluorescence. The membrane gaps of blood vessel endothelial tight junctions were measured using electron microscopy to visualize ultrastructural BBB alterations in one untreated and one Dex treated F98 glioma. Data were analyzed by two-way ANOVAs. In Dex treated animals EBD extravasation was significantly reduced in 9L (P < 0.001) and U87 (P = 0.008) models and showed a trend in F98 models (P = 0.053). In contrast, no significant differences of {sup 18}F-FET uptake were observed between Dex treated animals and control group except a decrease of the TBR in the 9L tumor model in PET (P < 0.01). Ultrastructural evaluation of tumor blood vessel endothelia revealed significant reduction of the cleft diameter between endothelial cells after Dex treatment in F98 model (P = 0.010). Despite a considerable reduction of BBB permeability in rat gliomas after Dex treatment, no relevant changes of {sup 18}F-FET uptake were noted in this experimental study. Thus, {sup 18}F-FET uptake in gliomas appears to be widely independent of the

  9. Enhancement in blood-tumor barrier permeability and delivery of liposomal doxorubicin using focused ultrasound and microbubbles: evaluation during tumor progression in a rat glioma model

    Science.gov (United States)

    Aryal, Muna; Park, Juyoung; Vykhodtseva, Natalia; Zhang, Yong-Zhi; McDannold, Nathan

    2015-03-01

    Effective drug delivery to brain tumors is often challenging because of the heterogeneous permeability of the ‘blood tumor barrier’ (BTB) along with other factors such as increased interstitial pressure and drug efflux pumps. Focused ultrasound (FUS) combined with microbubbles can enhance the permeability of the BTB in brain tumors, as well as the blood-brain barrier in the surrounding tissue. In this study, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used to characterize the FUS-induced permeability changes of the BTB in a rat glioma model at different times after implantation. 9L gliosarcoma cells were implanted in both hemispheres in male rats. At day 9, 14, or 17 days after implantation, FUS-induced BTB disruption using 690 kHz ultrasound and definity microbubbles was performed in one tumor in each animal. Before FUS, liposomal doxorubicin was administered at a dose of 5.67 mg kg-1. This chemotherapy agent was previously shown to improve survival in animal glioma models. The transfer coefficient Ktrans describing extravasation of the MRI contrast agent Gd-DTPA was measured via DCE-MRI before and after sonication. We found that tumor doxorubicin concentrations increased monotonically (823  ±  600, 1817  ±  732 and 2432  ±  448 ng g-1) in the control tumors at 9, 14 and 17 d. With FUS-induced BTB disruption, the doxorubicin concentrations were enhanced significantly (P drug delivery are relatively consistent over time, at least in this tumor model. These results are encouraging for the use of large drug carriers, as they suggest that even large/late-stage tumors can benefit from FUS-induced drug enhancement. Corresponding enhancements in Ktrans were found to be variable in large/late-stage tumors and not significantly different than controls, perhaps reflecting the size mismatch between the liposomal drug (~100 nm) and Gd-DTPA (molecular weight: 938 Da; hydrodynamic diameter: ≃2 nm). It may be necessary

  10. Interleukin-6 induces keratin expression in intestinal epithelial cells: potential role of keratin-8 in interleukin-6-induced barrier function alterations.

    Science.gov (United States)

    Wang, Lixin; Srinivasan, Shanthi; Theiss, Arianne L; Merlin, Didier; Sitaraman, Shanthi V

    2007-03-16

    Keratin 8 (K8) and keratin-18 (K18) are the major intermediate filament proteins in the intestinal epithelia. The regulation and function of keratin in the intestinal epithelia is largely unknown. In this study we addressed the role and regulation of K8 and K18 expression by interleukin 6 (IL-6). Caco2-BBE cell line and IL-6 null mice were used to study the effect of IL-6 on keratin expression. Keratin expression was studied by Northern blot, Western blot, and confocal microscopy. Paracellular permeability was assessed by apical-to-basal transport of a fluorescein isothiocyanate dextran probe (FD-4). K8 was silenced using the small interfering RNA approach. IL-6 significantly up-regulated mRNA and protein levels of K8 and K18. Confocal microscopy showed a reticular pattern of intracellular keratin localized to the subapical region after IL-6 treatment. IL-6 also induced serine phosphorylation of K8. IL-6 decreased paracellular flux of FD-4 compared with vehicle-treated monolayers. K8 silencing abolished the decrease in paracellular permeability induced by IL-6. Administration of dextran sodium sulfate (DSS) significantly increased intestinal permeability in IL-6-/- mice compared with wild type mice given DSS. Collectively, our data demonstrate that IL-6 regulates the colonic expression of K8 and K18, and K8/K18 mediates barrier protection by IL-6 under conditions where intestinal barrier is compromised. Thus, our data uncover a novel function of these abundant cytoskeletal proteins, which may have implications in intestinal disorders such as inflammatory bowel disease wherein barrier dysfunction underlies the inflammatory response.

  11. Structure-activity relationship studies of permeability modulating peptide AT-1002.

    Science.gov (United States)

    Li, Min; Oliver, Ed; Kitchens, Kelly M; Vere, John; Alkan, Sefik S; Tamiz, Amir P

    2008-08-15

    AT-1002 a 6-mer synthetic peptide belongs to an emerging novel class of compounds that reversibly increase paracellular transport of molecules across the epithelial barrier. The aim of this project was to elaborate on the structure-activity relationship of this peptide with the specific goal to replace the P2 cysteine amino acid. Herein, we report the discovery of peptides that exhibit reversible permeability enhancement properties with an increased stability profile.

  12. Interrelations between blood-brain barrier permeability and matrix metalloproteinases are differently affected by tissue plasminogen activator and hyperoxia in a rat model of embolic stroke

    Directory of Open Access Journals (Sweden)

    Michalski Dominik

    2012-01-01

    Full Text Available Abstract Background In ischemic stroke, blood-brain barrier (BBB regulations, typically involving matrix metalloproteinases (MMPs and inhibitors (TIMPs as mediators, became interesting since tissue plasminogen activator (tPA-related BBB breakdown with risk of secondary hemorrhage was considered to involve these mediators too. Despite high clinical relevance, detailed interactions are purely understood. After a pilot study addressing hyperoxia as potential neuroprotective co-treatment to tPA, we analyzed interrelations between BBB permeability (BBB-P, MMPs and TIMPs. Findings Rats underwent embolic middle cerebral artery occlusion (eMCAO and treatment with normobaric (NBO or hyperbaric oxygen (HBO, tPA, tPA+HBO, or no treatment. BBB-P was assessed by intravenously applied FITC-albumin at 4 or 24 hours. MMP-2/-9 and TIMP-1/-2 serum levels were determined at 5 or 25 hours. Time point-corrected partial correlations were used to explore interrelations of BBB-P in ischemic regions (extra-/intravasal FITC-albumin ratio and related serum markers. BBB-P correlated positively with MMP-2 and MMP-9 in controls, whereas hyperoxia led to an inverse association, most pronounced for HBO/MMP-9 (r = -0.606; P Conclusions HBO was found to reverse the positively directed interrelation of BBB-P and MMPs after eMCAO, but this effect failed to sustain in the expected amount when HBO and tPA were given simultaneously.

  13. Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones.

    Science.gov (United States)

    Eberhardt, Jacob L; Persson, Bertil R R; Brun, Arne E; Salford, Leif G; Malmgren, Lars O G

    2008-01-01

    We investigated the effects of global system for mobile communication (GSM) microwave exposure on the permeability of the blood-brain barrier and signs of neuronal damage in rats using a real GSM programmable mobile phone in the 900 MHz band. Ninety-six non-anaesthetized rats were either exposed to microwaves or sham exposed in TEM-cells for 2 h at specific absorption rates of average whole-body Specific Absorption Rates (SAR) of 0.12, 1.2, 12, or 120 mW/kg. The rats were sacrificed after a recovery time of either 14 or 28 d, following exposure and the extravazation of albumin, its uptake into neurons, and occurrence of damaged neurons was assessed. Albumin extravazation and also its uptake into neurons was seen to be enhanced after 14 d (Kruskal Wallis test: p = 0.02 and 0.002, respectively), but not after a 28 d recovery period. The occurrence of dark neurons in the rat brains, on the other hand, was enhanced later, after 28 d (p = 0.02). Furthermore, in the 28-d brain samples, neuronal albumin uptake was significantly correlated to occurrence of damaged neurons (Spearman r = 0.41; p < 0.01).

  14. Performance of a field-scale permeable reactive barrier based on organic substrate and zero-valent iron for in situ remediation of acid mine drainage.

    Science.gov (United States)

    Gibert, Oriol; Cortina, José Luis; de Pablo, Joan; Ayora, Carlos

    2013-11-01

    A permeable reactive barrier (PRB) was installed in Aznalcóllar (Spain) in order to rehabilitate the Agrio aquifer groundwater severely contaminated with acid mine drainage after a serious mining accident. The filling material of the PRB consisted of a mixture of calcite, vegetal compost and, locally, Fe(0) and sewage sludge. Among the successes of the PRB are the continuous neutralisation of pH and the removal of metals from groundwater within the PRB (removals of >95%). Among the shortcomings are the improper PRB design due to the complexity of the internal structure of the Agrio alluvial deposits (which resulted in an inefficient capture of the contaminated plume), the poor degradability of the compost used and the short residence time within the PRB (which hindered a complete sulphate reduction), the clogging of a section of the PRB and the heterogeneities of the filling material (which resulted in preferential flows within the PRB). Undoubtedly, it is only through accumulated experience at field-scale systems that the potentials and limits of the PRB technology can be determined.

  15. Effects of losartan on the blood-brain barrier permeability in long-term nitric oxide blockade-induced hypertensive rats.

    Science.gov (United States)

    Kucuk, Mutlu; Kaya, Mehmet; Kalayci, Rivaze; Cimen, Vedat; Kudat, Hasan; Arican, Nadir; Elmas, Imdat; Korkut, Ferruh

    2002-07-12

    Hypertension is closely associated with vascular endothelial dysfunction. The aim of this study was to investigate the effects of Angiotensin II (ANG II) receptor antagonist losartan on the blood-brain barrier (BBB) permeability in L-NAME-induced hypertension and/or in ANG II-induced acute hypertension in normotensive and hypertensive rats. Systolic blood pressure was measured by tail cuff method before, during and following L-NAME treatment (1 g/L). Losartan (3 mg/kg) was given to the animal for five days. Acute hypertension was induced by ANG II (60 microg/kg). Arterial blood pressure was directly measured on the day of the experiment. BBB disruption was quantified according to the extravasation of the albumin-bound Evans blue dye. Losartan significantly reduced the mean arterial blood pressure from 169 +/- 3.9 mmHg to 82 +/- 2.9 mmHg in L-NAME and from 171 +/- 2.9 mmHg to 84 +/- 2.9 in L-NAME plus losartan plus ANG II groups (p cerebral cortex significantly increased in L-NAME (p microvascular Evans blue dye efflux to brain, and losartan treatment attenuates this protein-bound dye transport into brain tissue presumably due to its protective effect on endothelial cells of brain vessels.

  16. 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.

    Science.gov (United States)

    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

  17. Magnetic-resonance imaging for kinetic analysis of permeability changes during focused ultrasound-induced blood-brain barrier opening and brain drug delivery.

    Science.gov (United States)

    Chai, Wen-Yen; Chu, Po-Chun; Tsai, Meng-Yen; Lin, Yu-Chun; Wang, Jiun-Jie; Wei, Kuo-Chen; Wai, Yau-Yau; Liu, Hao-Li

    2014-10-28

    Focused ultrasound (FUS) with the presence of microbubbles has been shown to induce transient and local opening of the blood-brain barrier (BBB) for the delivery of therapeutic molecules which normally cannot penetrate into the brain. The success of FUS brain-drug delivery relies on its integration with in-vivo imaging to monitor kinetic change of therapeutic molecules into the brain. In this study, we developed a dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) technique for kinetic analysis of delivered molecules during FUS-BBB opening. Three kinetic parameters (Ktrans, Ve, Kep) were characterized dynamically to describe BBB-permeability at two FUS exposure conditions (0.4 or 0.8MPa) over 24h. Ktrans, defined as the influx volume transfer constant from plasma to EES, and Ve, the EES volume fraction, were both found to be pressure-dependent. Ktrans and Ve showed a peak increase of 0.0086-0.0131min(-1) (for 0.4-0.8MPa pressure), and 0.0431-0.0692, respectively, immediately after FUS exposure. Both parameters subsequently decreased exponentially as a function of time, with estimated half-lives of decay of 2.89-5.3 and 2.2-4.93h, respectively. The kinetics of Kep, defined as the efflux rate constant from the extracellular extravascular space (EES) to the plasma, were complementary to Ktrans, with an initial decrease from 0.2010 to 0.1901min(-1) followed by a significantly longer recovery time (half-life of 17.39-99.92h). Our observations strongly supported the existence of imbalanced and mismatched kinetics of influx (Ktrans) and efflux (Kep) between the plasma and EES, indicating the existence of directional permeability during FUS-BBB opening. We further showed that kinetic change determined by DCE-MRI correlated well with the concentration of Evans Blue (EB)-albumin (coefficient of 0.74-0.89). These findings suggest that MRI kinetic monitoring may serve as an alternative method for in-vivo monitoring of pharmacokinetics and pharmacodynamics (PK

  18. Critical role of Keratin 1 in maintaining epithelial barrier and correlation of its down-regulation with the progression of inflammatory bowel disease.

    Science.gov (United States)

    Dong, Xiangqian; Liu, Zichao; Lan, Danfeng; Niu, Junkun; Miao, Jiarong; Yang, Gang; Zhang, Fengrui; Sun, Yang; Wang, Kunhua; Miao, Yinglei

    2017-04-15

    Inflammatory bowel disease (IBD) is the result of a chronic intestinal inflammatory response which usually occurred in colon and small intestine. Keratins constitute the intermediate filament cytoskeleton in all epithelia. The present study was intended to explore the role of Keratin 1 (KRT1) in the progress of IBD. In normal intestinal tissue, the expression of KRT1 was detected by RT-PCR and Western blot. The levels of KRT1 protein significantly decreased in serum samples of IBD patients as compared with sera of healthy controls. Immunohistochemistry revealed that the expression of KRT1 decreased in various intestinal diseases, especially in Crohn's disease and ulcerative colitis. Furthermore, down-regulated KRT1 was correlated with the severity of IBD. The overexpression of KRT1 maintained epithelial barrier in Caco-2 cells after IL-1β treatment. Furthermore, IL-1β-induced disruption of tight junction became significantly attenuated in KRT1 over-expressing Caco-2 cells as compared with control cells. Thus, KRT1 played an important role of maintaining epithelial barrier and its down-regulation in intestinal tissue was correlated with the progression of IBD. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. 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.

  20. Intra-Subtype Variation in Enteroadhesion Accounts for Differences in Epithelial Barrier Disruption and Is Associated with Metronidazole Resistance in Blastocystis Subtype-7

    Science.gov (United States)

    Tan, Kevin Shyong Wei

    2014-01-01

    Blastocystis is an extracellular, enteric pathogen that induces intestinal disorders in a range of hosts including humans. Recent studies have identified potential parasite virulence factors in and host responses to this parasite; however, little is known about Blastocystis-host attachment, which is crucial for colonization and virulence of luminal stages. By utilizing 7 different strains of the parasite belonging to two clinically relevant subtypes ST-4 and ST-7, we investigated Blastocystis-enterocyte adhesion and its association with parasite-induced epithelial barrier disruption. We also suggest that drug resistance in ST-7 strains might result in fitness cost that manifested as impairment of parasite adhesion and, consequently, virulence. ST-7 parasites were generally highly adhesive to Caco-2 cells and preferred binding to intercellular junctions. These strains also induced disruption of ZO-1 and occludin tight junction proteins as well as increased dextran-FITC flux across epithelial monolayers. Interestingly, their adhesion was correlated with metronidazole (Mz) susceptibility. Mz resistant (Mzr) strains were found to be less pathogenic, owing to compromised adhesion. Moreover, tolerance of nitrosative stress was also reduced in the Mzr strains. In conclusion, the findings indicate that Blastocystis attaches to intestinal epithelium and leads to epithelial barrier dysfunction and that drug resistance might entail a fitness cost in parasite virulence by limiting entero-adhesiveness. This is the first study of the cellular basis for strain-to-strain variation in parasite pathogenicity. Intra- and inter-subtype variability in cytopathogenicity provides a possible explanation for the diverse clinical outcomes of Blastocystis infections. PMID:24851944

  1. Effects of initial iron corrosion rate on long-term performance of iron permeable reactive barriers: column experiments and numerical simulation.

    Science.gov (United States)

    suk O, Jin; Jeen, Sung-Wook; Gillham, Robert W; Gui, Lai

    2009-01-26

    Column experiments and numerical simulation were conducted to test the hypothesis that iron material having a high corrosion rate is not beneficial for the long-term performance of iron permeable reactive barriers (PRBs) because of faster passivation of iron and greater porosity loss close to the influent face of the PRBs. Four iron materials (Connelly, Gotthart-Maier, Peerless, and ISPAT) were used for the column experiments, and the changes in reactivity toward cis-dichloroethene (cis-DCE) degradation in the presence of dissolved CaCO3 were evaluated. The experimental results showed that the difference in distribution of the accumulated precipitates, resulting from differences in iron corrosion rate, caused a difference in the migration rate of the cis-DCE profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region close to the influent end for the material having a higher corrosion rate. For the numerical simulation, the accumulation of secondary minerals and reactivity loss of iron were coupled using an empirically-derived relationship that was incorporated into a multi-component reactive transport model. The simulation results provided a reasonable representation of the evolution of iron reactivity toward cis-DCE treatment and the changes in geochemical conditions for each material, consistent with the observed data. The simulations for long-term performance were also conducted to further test the hypothesis and predict the differences in performance over a period of 40 years under typical groundwater conditions. The predictions showed that the cases of higher iron corrosion rates had earlier cis-DCE breakthrough and more reduction in porosity starting from near the influent face, due to more accumulation of carbonate minerals in that region. Therefore, both the experimental and simulation results appear to support the hypothesis and suggest that reactivity changes of iron materials resulting from

  2. Recovery of Cr as Cr(III) from Cr(VI)-contaminated kaolinite clay by electrokinetics coupled with a permeable reactive barrier.

    Science.gov (United States)

    Suzuki, Tasuma; Kawai, Katsunori; Moribe, Mai; Niinae, Masakazu

    2014-08-15

    Zero-valent iron (Fe(0)) and magnetite (Fe3O4) were investigated as potential reductants in an electrokinetic/permeable reactive barrier hybrid system (EK/PRB) for the recovery of Cr as Cr(III) from Cr(VI)-contaminated kaolinite. For the EK/Fe(0) PRB, regardless of the pH in the anode well, the system facilitated the reduction of Cr(VI) into Cr(III), but the recovery of the Cr(III) in the PRB was low. Conversely, the reduction of Cr(VI) occurred only in the PRB for the EK/Fe3O4 PRB. However, when the anode pH was not controlled and the soil pH values correspondingly decreased gradually from the anode side, a greater fraction of Cr(VI) sorbed onto the kaolinite; as a result, a lower amount of Cr(VI) migrated to the Fe3O4 PRB. In addition, it was found that the majority of Cr(VI) migrating to the Fe3O4 PRB retained its oxidation state without being converted into Cr(III). These two adverse effects were mitigated by maintaining the soil pH values at 6.8, but at the same time, 18% of Cr(VI) penetrated through the Fe3O4 PRB. The penetration of Cr(VI) through the Fe3O4 PRB was successfully prevented by increasing the reaction time through the introduction of a cation exchange membrane between the Fe3O4 PRB and the anode well. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Remediation of persistent organic pollutant-contaminated soil using biosurfactant-enhanced electrokinetics coupled with a zero-valent iron/activated carbon permeable reactive barrier.

    Science.gov (United States)

    Sun, Yuchao; Gao, Ke; Zhang, Yun; Zou, Hua

    2017-10-10

    Zero-valent iron/activated carbon (Fe/C) particles can degrade persistent organic pollutants via micro-electrolysis and therefore, they may be used to develop materials for permeable reactive barriers (PRBs). In this study, surfactant-enhanced electrokinetics (EK) was coupled with a Fe/C-PRB to treat phenanthrene (PHE) and 2,4,6-trichlorophenol (TCP) co-contaminated clay soil. An environment-friendly biosurfactant, rhamnolipid, was selected as the solubility-enhancing agent. Five bench-scale tests were conducted to investigate the performance of EK-PRB on PHE and TCP removal from soil as well as the impact of pH and rhamnolipid concentration. The results show that both PHE and TCP, driven by electro-osmotic flow (EOF), moved toward the cathode and reacted with the Fe/C-PRB. Catholyte acidification and rhamnolipid concentration increase improved the removal efficiencies of PHE and TCP. The highest removal efficiency of PHE in soil column was five times the efficiency of the control group on which only EK was applied (49.89 versus 9.40%). The highest removal efficiency of TCP in soil column was 4.5 times the efficiency of the control group (64.60 versus 14.30%). Desorption and mobility of PHE and TCP improved with the increase of rhamnolipid concentration when this exceeded the critical micelle concentration. This study indicates that the combination of EK and a Fe/C-PRB is efficient and promising for removing persistent organic pollutants (POPs) from contaminated soil with the enhancement of rhamnolipid.

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

    Science.gov (United States)

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

    2017-02-01

    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 second-order reaction rate constant. Furthermore, the model accounts for the HPRB lifetime as a function of the oxidant consumption by reaction with upward vapors and its progressive dissolution and leaching by infiltrating water. Simulation results by this new model closely replicate previous lab-scale tests carried out on trichloroethylene (TCE) using a HPRB containing a mixture of potassium permanganate, water and sand. In view of field applications, design criteria, in terms of the minimum HPRB thickness required to attenuate vapors at acceptable risk-based levels and the expected HPRB lifetime, are determined from site-specific conditions such as vapor source concentration, water infiltration rate and HPRB mixture. The results clearly show the field-scale feasibility of this alternative vapor mitigation system for the treatment of chlorinated solvents. Depending on the oxidation kinetic of the target contaminant, a 1 m thick HPRB can ensure an attenuation of vapor concentrations of orders of magnitude up to 20 years, even for vapor source concentrations up to 10 g/m3. A demonstrative application for representative contaminated site conditions also shows the feasibility of this mitigation system from an economical point of view with capital costs potentially somewhat lower than those of other remediation options, such as soil vapor extraction systems. Overall, based on the experimental and theoretical evaluation thus far, field-scale tests are warranted to verify the potential and cost-effectiveness of HPRBs for vapor mitigation control under various conditions of application.

  5. Investigating the potential for long-term permeable reactive barrier (PRB) monitoring from the electrical signatures associated with the reduction in reactive iron performance

    Energy Technology Data Exchange (ETDEWEB)

    Slater, Lee D.; Korte, N.; Baker, J.

    2005-12-14

    The objective of this work was to conduct laboratory and field experiments to determine the sensitivity of low frequency electrical measurements (resistivity and induced polarization) to the processes of corrosion and precipitation that are believed to limit permeable reactive barrier (PRB) performance. The research was divided into four sets of experiments that were each written up and submitted to a peer-reviewed journal: [1] A laboratory experiment to define the controls of aqueous chemistry (electrolyte activity; pH; valence) and total zero valent iron (Fe0) available surface area on the electrical properties of Fe0 columns. [2] A laboratory experiment to determine the impact of corrosion and precipitation on the electrical response of synthetic Fe0 columns as a result of geochemical reactions with NaSO4 and NaCO3 electrolytes. [3] Laboratory experiments on a sequence of cores retrieved from the Kansas City PRB to determine the magnitude of electrical and geochemical changes within a field active PRB after eight years of operation [4] Field-scale cross borehole resistivity and induced polarization monitoring of the Kansas City PRB to evaluate the potential of electrical imaging as a technology for non-invasive, long-term monitoring of indicators of reduced PRB performance This report first summarizes the findings of the four major experiments conducted under this research. The reader is referred to the four papers in Appendices 1-4 for a full description of each experiment, including motivation and significance, technical details, findings and implications. The deliverables of the project, including the publications, conference papers and new collaborative arrangements that have resulted are then described. Appendices 5-6 contain two technical reports written by co-PI Korte describing (1) supporting geochemical measurements, and (2) the coring procedure, conducted at the Kansas City PRB as part of this project.

  6. Ablation of CD11c(hi) dendritic cells exacerbates Japanese encephalitis by regulating blood-brain barrier permeability and altering tight junction/adhesion molecules.

    Science.gov (United States)

    Kim, Jin Hyoung; Hossain, Ferdaus Mohd Altaf; Patil, Ajit Mahadev; Choi, Jin Young; Kim, Seong Bum; Uyangaa, Erdenebelig; Park, Sang-Youel; Lee, John-Hwa; Kim, Bumseok; Kim, Koanhoi; Eo, Seong Kug

    2016-10-01

    Japanese encephalitis (JE), characterized by extensive neuroinflammation following infection with neurotropic JE virus (JEV), is becoming a leading cause of viral encephalitis due to rapid changes in climate and demography. The blood-brain barrier (BBB) plays an important role in restricting neuroinvasion of peripheral leukocytes and virus, thereby regulating the progression of viral encephalitis. In this study, we explored the role of CD11c(hi) dendritic cells (DCs) in regulating BBB integrity and JE progression using a conditional depletion model of CD11c(hi) DCs. Transient ablation of CD11c(hi) DCs resulted in markedly increased susceptibility to JE progression along with highly increased neuro-invasion of JEV. In addition, exacerbated JE progression in CD11c(hi) DC-ablated hosts was closely associated with increased expression of proinflammatory cytokines (IFN-β, IL-6, and TNF-α) and CC chemokines (CCL2, CCL3, CXCL2) in the brain. Moreover, our results revealed that the exacerbation of JE progression in CD11c(hi) DC-ablated hosts was correlated with enhanced BBB permeability and reduced expression of tight junction and adhesion molecules (claudin-5, ZO-1, occluding, JAMs). Ultimately, our data conclude that the ablation of CD11c(hi) DCs provided a subsidiary impact on BBB integrity and the expression of tight junction/adhesion molecules, thereby leading to exacerbated JE progression. These findings provide insight into the secondary role of CD11c(hi) DCs in JE progression through regulation of BBB integrity and the expression of tight junction/adhesion molecules. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. The proton permeability of self-assembled polymersomes and their neuroprotection by enhancing a neuroprotective peptide across the blood-brain barrier after modification with lactoferrin

    Science.gov (United States)

    Yu, Yuan; Jiang, Xinguo; Gong, Shuyu; Feng, Liang; Zhong, Yanqiang; Pang, Zhiqing

    2014-02-01

    Biotherapeutics such as peptides possess strong potential for the treatment of intractable neurological disorders. However, because of their low stability and the impermeability of the blood-brain barrier (BBB), biotherapeutics are difficult to transport into brain parenchyma via intravenous injection. Herein, we present a novel poly(ethylene glycol)-poly(d,l-lactic-co-glycolic acid) polymersome-based nanomedicine with self-assembled bilayers, which was functionalized with lactoferrin (Lf-POS) to facilitate the transport of a neuroprotective peptide into the brain. The apparent diffusion coefficient (D*) of H+ through the polymersome membrane was 5.659 × 10-26 cm2 s-1, while that of liposomes was 1.017 × 10-24 cm2 s-1. The stability of the polymersome membrane was much higher than that of liposomes. The uptake of polymersomes by mouse brain capillary endothelial cells proved that the optimal density of lactoferrin was 101 molecules per polymersome. Fluorescence imaging indicated that Lf101-POS was effectively transferred into the brain. In pharmacokinetics, compared with transferrin-modified polymersomes and cationic bovine serum albumin-modified polymersomes, Lf-POS obtained the greatest BBB permeability surface area and percentage of injected dose per gram (%ID per g). Furthermore, Lf-POS holding S14G-humanin protected against learning and memory impairment induced by amyloid-β25-35 in rats. Western blotting revealed that the nanomedicine provided neuroprotection against over-expression of apoptotic proteins exhibiting neurofibrillary tangle pathology in neurons. The results indicated that polymersomes can be exploited as a promising non-invasive nanomedicine capable of mediating peptide therapeutic delivery and controlling the release of drugs to the central nervous system.

  8. X-231A demonstration of in-situ remediation of DNAPL compounds in low permeability media by soil fracturing with thermally enhanced mass recovery or reactive barrier destruction

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L. [Oak Ridge National Lab., TN (United States)]|[Colorado School of Mines, Golden, CO (United States). Environmental Science and Engineering Div.; Lowe, K.S. [Oak Ridge National Lab., Grand Junction, CO (United States). Life Sciences Div.; Murdoch, L.D. [FRx, Inc., Cincinnati, OH (United States)]|[Clemson Univ., SC (United States); Slack, W.W. [FRx, Inc., Cincinnati, OH (United States); Houk, T.C. [Lockheed Martin Energy Systems, Piketon, OH (United States)

    1998-03-01

    The overall goal of the program of activities is to demonstrate robust and cost-effective technologies for in situ remediation of DNAPL compounds in low permeability media (LPM), including adaptations and enhancements of conventional technologies to achieve improved performance for DNAPLs in LPM. The technologies sought should be potential for application at simple, small sites (e.g., gasoline underground storage tanks) as well as at complex, larger sites (e.g., DOE land treatment units). The technologies involved in the X-231A demonstration at Portsmouth Gaseous Diffusion Plant (PORTS) utilized subsurface manipulation of the LPM through soil fracturing with thermally enhanced mass recovery or horizontal barrier in place destruction. To enable field evaluation of these approaches, a set of four test cells was established at the X-231A land treatment unit at the DOE PORTS plant in August 1996 and a series of demonstration field activities occurred through December 1997. The principal objectives of the PORTS X-231A demonstration were to: determine and compare the operational features of hydraulic fractures as an enabling technology for steam and hot air enhanced soil vapor extraction and mass recovery, in situ interception and reductive destruction by zero valent iron, and in situ interception and oxidative destruction by potassium permanganate; determine the interaction of the delivered agents with the LPM matrix adjacent to the fracture and within the fractured zone and assess the beneficial modifications to the transport and/or reaction properties of the LPM deposit; and determine the remediation efficiency achieved by each of the technology strategies.

  9. Permeable Reactive Barrier: Technology Update

    Science.gov (United States)

    2011-06-01

    Zeolites have been widely used for a number of water treatment applications, from removing heavy metals in wastewater treatment plants to the treatment of...number of wastewater treatment applications. Organophilic clays exhibit a synergistic effect when used as pretreatment to remove oil and grease prior...investigators have installed biowalls filled with a variety of waste cellulose solids (e.g., sawdust and mulch) for the treatment of nitrate-contaminated

  10. Changes in Ground-Water Quality near Two Granular-Iron Permeable Reactive Barriers in a Sand and Gravel Aquifer, Cape Cod, Massachusetts, 1997-2000

    Science.gov (United States)

    Savoie, Jennifer G.; Kent, Douglas B.; Smith, Richard L.; LeBlanc, Denis R.; Hubble, David W.

    2004-01-01

    Two experimental permeable reactive barriers (PRBs) of granular zero-valent iron were emplaced in the path of a tetrachloroethene plume (the Chemical Spill-10 plume) at the Massachusetts Military Reservation, Cape Cod, Massachusetts, in June 1998. The goal of the field experiment was to achieve emplacement of a granular-iron PRB deeper than attempted before. The PRBs were expected to create a reducing environment and degrade the tetrachloroethene by reductive dechlorination. The goal of the work presented in this report was to observe temporary and sustained changes to the ground-water chemistry downgradient from the PRBs. A hydraulic-fracturing method involving injection of the granular iron with a guar-biopolymer and enzyme slurry was used to install the parallel 30- to 33-foot-wide wall-shaped barriers at a depth of 82 to 113 feet below land surface. An acetic acid and enzyme mixture was subsequently injected in wells near the barriers to degrade the guar biopolymer. Prior to the emplacement, tetrachloroethene concentrations in the Chemical Spill-10 plume at the study area were as high as 250 micrograms per liter. Other water properties in the plume generally were similar to the properties of uncontaminated ground water in the area, which typically has dissolved oxygen concentrations of 250 to 375 micromoles per liter, pH of 5.5 to 6.0, and specific conductance of 60 to 90 microsiemens per centimeter. Water-quality samples were collected periodically from monitoring wells near the PRBs to determine how the emplacement of the granular-iron walls altered the ground-water quality. In addition, an automated well-sampling device measured temperature, specific conductance, pH, and dissolved oxygen every 1?4 days for 16 months in a well downgradient from the two parallel PRBs. Temporary increases (lasting about 5 to 6 months) in specific conductance were observed downgradient from the PRBs as a result of the sodium chloride, potassium carbonate, and other salts

  11. Protein kinase C δ signaling is required for dietary prebiotic-induced strengthening of intestinal epithelial barrier function

    Science.gov (United States)

    Wu, Richard Y.; Abdullah, Majd; Määttänen, Pekka; Pilar, Ana Victoria C.; Scruten, Erin; Johnson-Henry, Kathene C.; Napper, Scott; O’Brien, Catherine; Jones, Nicola L.; Sherman, Philip M.

    2017-01-01

    Prebiotics are non-digestible oligosaccharides that promote the growth of beneficial gut microbes, but it is unclear whether they also have direct effects on the intestinal mucosal barrier. Here we demonstrate two commercial prebiotics, inulin and short-chain fructo-oligosaccharide (scFOS), when applied onto intestinal epithelia in the absence of microbes, directly promote barrier integrity to prevent pathogen-induced barrier disruptions. We further show that these effects involve the induction of select tight junction (TJ) proteins through a protein kinase C (PKC) δ-dependent mechanism. These results suggest that in the absence of microbiota, prebiotics can directly exert barrier protective effects by activating host cell signaling in the intestinal epithelium, which represents a novel alternative mechanism of action of prebiotics. PMID:28098206

  12. Crustal permeability

    Science.gov (United States)

    Gleeson, Tom; Ingebritsen, Steven E.

    2016-01-01

    Permeability is the primary control on fluid flow in the Earth’s crust and is key to a surprisingly wide range of geological processes, because it controls the advection of heat and solutes and the generation of anomalous pore pressures.  The practical importance of permeability – and the potential for large, dynamic changes in permeability – is highlighted by ongoing issues associated with hydraulic fracturing for hydrocarbon production (“fracking”), enhanced geothermal systems, and geologic carbon sequestration.  Although there are thousands of research papers on crustal permeability, this is the first book-length treatment.  This book bridges the historical dichotomy between the hydrogeologic perspective of permeability as a static material property and the perspective of other Earth scientists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. 

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

    Science.gov (United States)

    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.

  14. Potato glycoalkaloids adversely affect intestinal permeability and aggravate inflammatory bowel disease.

    Science.gov (United States)

    Patel, Bijal; Schutte, Robert; Sporns, Peter; Doyle, Jason; Jewel, Lawrence; Fedorak, Richard N

    2002-09-01

    Disruption of epithelial barrier integrity is important in the initiation and cause of inflammatory bowel disease (IBD). Glycoalkaloids, solanine (S), and chaconine (C) are naturally present in potatoes, can permeabilize cholesterol-containing membranes, and lead to disruption of epithelial barrier integrity. Frying potatoes concentrates glycoalkaloids. Interestingly, the prevalence of IBD is highest in countries where fried potatoes consumption is highest. To further understand the role of potato glycoalkaloids on intestinal barrier integrity, we examined the effect of varying concentrations of solanine and chaconine on intestinal permeability and function. Solanine (0-50 microM), chaconine (0-20 microM), or a 1:1 mixture (0-20 microM) were exposed to T84 cultured epithelial monolayers for varying periods of time to determine concentration response effect on epithelial permeability. Next, a 1:1 mixture (5 microM) of solanine-to-chaconine (C:S) was exposed to sheets of normal murine small intestine, mounted in Ussing chambers, from control and interleukin-10 gene-deficient mice to determine whether glycoalkaloids affected intestine from mice with a genetic predisposition for IBD greater than controls. Finally, the effects of glycoalkaloids on colonic histologic injury were examined in mice orally fed amounts of glycoalkaloids that would normally be consumed in a human diet. Glycoalkaloids embedded and permeabilized the T84 monolayer epithelial membrane bilayer in a concentration-dependent fashion, with C:S > C > S. In vitro Ussing chamber experiments also illustrated a concentration-dependent disruption of intestinal barrier integrity in animals with a genetic predisposition to develop IBD, but not in control animals. Similarly, in vivo oral feeding experiments demonstrated that C:S ingestion, at physiologic concentrations, aggravated histologic colonic injury in mice genetically predisposed to developing IBD. Concentrations of glycoalkaloids normally available

  15. Characterization of immortalized choroid plexus epithelial cell lines for studies of transport processes across the blood-cerebrospinal fluid barrier

    Directory of Open Access Journals (Sweden)

    Kläs Juliane

    2010-08-01

    Full Text Available Abstract Background Two rodent choroid plexus (CP epithelial cell lines, Z310 and TR-CSFB, were compared with primary rat CP epithelial cells and intact CP tissue with respect to transport protein expression, function and tight junction (TJ formation. Methods For expression profiles of transporters and TJ proteins, qPCR and western blot analysis were used. Uptake assays were performed to study the functional activity of transporters and TJ formation was measured by trans-epithelial electrical resistance (TEER and visualized by electron microscopy. Results The expression of known ATP-binding cassette (Abc transporter and solute carrier (Slc genes in CP was confirmed by qPCR. Primary cells and cell lines showed similar, but overall lower expression of Abc transporters and absent Slc expression when compared to intact tissue. Consistent with this Mrp1, Mrp4 and P-gp protein levels were higher in intact CP compared to cell lines. Functionality of P-gp and Mrp1 was confirmed by Calcein-AM and CMFDA uptake assays and studies using [3H]bis-POM-PMEA as a substrate indicated Mrp4 function. Cell lines showed low or absent TJ protein expression. After treatment of cell lines with corticosteroids, RNA expression of claudin1, 2 and 11 and occludin was elevated, as well as claudin1 and occludin protein expression. TJ formation was further investigated by freeze-fracture electron microscopy and only rarely observed. Increases in TJ particles with steroid treatment were not accompanied by an increase in transepithelial electrical resistance (TEER. Conclusion Taken together, immortalized cell lines may be a tool to study transport processes mediated by P-gp, Mrp1 or Mrp4, but overall expression of transport proteins and TJ formation do not reflect the situation in intact CP tissue.

  16. Notional Permeability

    NARCIS (Netherlands)

    Kik, R.; Van den Bos, J.P.; Maertens, J.; Verhagen, H.J.; Van der Meer, J.W.

    2012-01-01

    Different layer design of a rock slope and under layers has a large effect on the strengths on the rock slope itself. In the stability formula developed of VAN DER MEER [1988] this effect is represented by the term Notional Permeability with symbol P. A more open, or permeable, structure underneath

  17. 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.

  18. Multiple roles for keratin intermediate filaments in the regulation of epithelial barrier function and apico-basal polarity.

    Science.gov (United States)

    Salas, Pedro J; Forteza, Radia; Mashukova, Anastasia

    2016-01-01

    As multicellular organisms evolved a family of cytoskeletal proteins, the keratins (types I and II) expressed in epithelial cells diversified in more than 20 genes in vertebrates. There is no question that keratin filaments confer mechanical stiffness to cells. However, such a number of genes can hardly be explained by evolutionary advantages in mechanical features. The use of transgenic mouse models has revealed unexpected functional relationships between keratin intermediate filaments and intracellular signaling. Accordingly, loss of keratins or mutations in keratins that cause or predispose to human diseases, result in increased sensitivity to apoptosis, regulation of innate immunity, permeabilization of tight junctions, and mistargeting of apical proteins in different epithelia. Precise mechanistic explanations for these phenomena are still lacking. However, immobilization of membrane or cytoplasmic proteins, including chaperones, on intermediate filaments ("scaffolding") appear as common molecular mechanisms and may explain the need for so many different keratin genes in vertebrates.

  19. Effect of rhamnolipids on permeability across Caco-2 cell monolayers.

    Science.gov (United States)

    Wallace, Charity J; Medina, Scott H; ElSayed, Mohamed E H

    2014-04-01

    This report describes the effect of rhamnolipids (RLs), an amphiphilic biosurfactant produced by the bacterium Pseudomonas aeruginosa, on the integrity and permeability across Caco-2 cell monolayers. We measured the trans-epithelial electrical resistance (TEER) and permeability of [(14)C]mannitol across Caco-2 cell monolayers upon incubation with 0.01-5.0% v/v RLs as a function of incubation time (30, 60, 90, and 120 min). We also studied the recovery of RL-treated Caco-2 cell monolayers upon incubation with Kaempferol, which is a natural flavonoid that promotes the assembly of the tight junctions. TEER of Caco-2 cell monolayers incubated with 0.01-5.0% v/v RLs solution dropped to 80-28% of that of untreated cells. Decline in TEER was associated with an increase in [(14)C]mannitol permeability as a function of RLs concentration and incubation time with Caco-2 cells. Incubation of RLs-treated Caco-2 cell monolayers with normal culture medium for 48 h did not restore barrier integrity. Whereas, incubation of a RLs-treated Caco-2 cells with culture medium containing Kaempferol for 24 h restored barrier function indicated by the higher TEER and lower [(14)C]mannitol permeability values. These results show the ability of RLs to modulate the integrity and permeability of Caco-2 cell monolayers in a concentration- and time-dependent fashion, which suggest their potential to function as a non-toxic permeation enhancer.

  20. The digestive neuronal-glial-epithelial unit: a new actor in gut health and disease.

    Science.gov (United States)

    Neunlist, Michel; Van Landeghem, Laurianne; Mahé, Maxime M; Derkinderen, Pascal; des Varannes, Stanislas Bruley; Rolli-Derkinderen, Malvyne

    2013-02-01

    The monolayer of columnar epithelial cells lining the gastrointestinal tract--the intestinal epithelial barrier (IEB)--is the largest exchange surface between the body and the external environment. The permeability of the IEB has a central role in the regulation of fluid and nutrient intake as well as in the control of the passage of pathogens. The functions of the IEB are highly regulated by luminal as well as internal components, such as bacteria or immune cells, respectively. Evidence indicates that two cell types of the enteric nervous system (ENS), namely enteric neurons and enteric glial cells, are potent modulators of IEB functions, giving rise to the novel concept of a digestive 'neuronal-glial-epithelial unit' akin to the neuronal-glial-endothelial unit in the brain. In this Review, we summarize findings demonstrating that the ENS is a key regulator of IEB function and is actively involved in pathologies associated with altered barrier function.

  1. The cell line NCl-H441 is a useful in vitro model for transport studies of human distal lung epithelial barrier.

    Science.gov (United States)

    Salomon, Johanna J; Muchitsch, Viktoria E; Gausterer, Julia C; Schwagerus, Elena; Huwer, Hanno; Daum, Nicole; Lehr, Claus-Michael; Ehrhardt, Carsten

    2014-03-03

    The lack of a well characterized, continuously growing in vitro model of human distal lung epithelial phenotype constitutes a serious limitation in the area of inhalation biopharmaceutics, particularly in the context of transepithelial transport studies. Here, we investigated if a human lung adenocarcinoma cell line, NCl-H441, has potential to serve as an in vitro model of human distal lung epithelium. The development of barrier properties was studied by immunocytochemistry (ICC) against the junction proteins zonula occludens protein 1 (ZO-1) and E-cadherin and measurement of transepithelial electrical resistance (TEER). Moreover, transport studies with the paracellular marker compounds fluorescein sodium and fluorescein isothiocyanate (FITC)-labeled dextrans of molecular weights ranging from 4 to 70 kDa were carried out. The expression of P-glycoprotein (P-gp; ABCB1) and organic cation transporters (OCT/Ns; SLC22A1-A5) was investigated by ICC and immunoblot. P-gp function was assessed by monolayer release and bidirectional transport studies using rhodamine 123 (Rh123) and the inhibitors verapamil and LY335979. Uptake of 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP(+)) was measured, in order to assess organic cation transporter function in vitro. Furthermore, the inhibitory potential of several organic cations on ASP(+) uptake was studied. NCl-H441 cells, when grown under liquid-covered conditions, formed confluent, electrically tight monolayers with peak TEER values of approximately 1000 Ω·cm(2), after 8-12 days in culture. These monolayers were able to differentiate paracellularly transported substrates according to their molecular weight. Presence of P-gp, OCT1, OCT2, OCT3, OCTN1, and OCTN2 was confirmed by Western blot and ICC and was similar to data from freshly isolated human alveolar epithelial cells in primary culture. Rh123 release from NCI-H441 monolayers was time-dependent and showed low, albeit significant attenuation by both inhibitors

  2. Enhancement of Blood–Brain Barrier Permeability and Delivery of Antisense Oligonucleotides or Plasmid DNA to the Brain by the Combination of Bubble Liposomes and High-Intensity Focused Ultrasound

    Directory of Open Access Journals (Sweden)

    Yoichi Negishi

    2015-09-01

    Full Text Available The blood–brain barrier (BBB is a major obstacle that prevents therapeutic drugs or genes from being delivered to the central nervous system. Therefore, it is important to develop methods to enhance the permeability of the BBB. We have developed echo-contrast gas (C3F8 entrapping liposomes (Bubble liposomes, BLs that can work as a gene delivery tool in combination with ultrasound (US exposure. Here, we studied whether the permeability of the BBB can be enhanced by the combination of BLs and high-intensity focused ultrasound (HIFU. Mice were intravenously injected with Evans blue (EB. BLs were subsequently injected, and the right hemispheres were exposed to HIFU. As a result, the accumulation of EB in the HIFU-exposed brain hemispheres was increased over that observed in the non-HIFU-exposed hemispheres, depending on the intensity and the duration of the HIFU. Similarly, the combination of BLs and HIFU allowed fluorescent-labeled antisense oligonucleotides to be delivered into the HIFU-exposed left hemispheres of the treated mice. Furthermore, a firefly luciferase-expressing plasmid DNA was delivered to the brain by the combination method of BLs and HIFU, which resulted in the increased gene expression in the brain at the focused-US exposure site. These results suggest that the method of combining BLs and HIFU together serves as a useful means for accelerating the permeability of BBB and thereby enabling antisense oligonucleotides or genes to be delivered to the focused brain site.

  3. Ginger Extract Suppresses Inflammatory Response and Maintains Barrier Function in Human Colonic Epithelial Caco-2 Cells Exposed to Inflammatory Mediators.

    Science.gov (United States)

    Kim, Yunyoung; Kim, Dong-Min; Kim, Ji Yeon

    2017-05-01

    The beneficial effects of ginger in the management of gastrointestinal disturbances have been reported. In this study, the anti-inflammatory potential of ginger extract was assessed in a cellular model of gut inflammation. In addition, the effects of ginger extract and its major active compounds on intestinal barrier function were evaluated. The response of Caco-2 cells following exposure to a mixture of inflammatory mediators [interleukin [IL]-1β, 25 ng/mL; lipopolysaccharides [LPS], 10 ng/mL; tumor necrosis factor [TNF]-α, 50 ng/mL; and interferon [INF]-γ, 50 ng/mL] were assessed by measuring the levels of secreted IL-6 and IL-8. In addition, the mRNA levels of cyclooxygenase-2 and inducible nitric oxide synthase were measured. Moreover, the degree of nuclear factor (NF)-κB inhibition was examined, and the intestinal barrier function was determined by measuring the transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran transfer. It was observed that ginger extract and its constituents improved inflammatory responses by decreasing the levels of nitrite, PGE2, IL-6, and IL-8 via NF-κB inhibition. The ginger extract also increased the TEER and decreased the transfer of FITC-dextran from the apical side of the epithelium to the basolateral side. Taken together, these results show that ginger extract may be developed as a functional food for the maintenance of gastrointestinal health. © 2017 Institute of Food Technologists®.

  4. Compartmentalization of vascular endothelial growth factor to the epithelial surface of the human lung.

    Science.gov (United States)

    Kaner, R J; Crystal, R G

    2001-04-01

    Based on assessment of mRNA expression, the lung is a major site of expression of the vascular endothelial growth factor (VEGF) gene, largely from type II alveolar epithelial cells. With the knowledge that VEGF can function to induce vascular leak, we hypothesized that to protect the lung from pulmonary edema, the VEGF produced in the lung must be compartmentalized from the pulmonary endothelium, and thus must be compartmentalized to the surface of the respiratory epithelium. To assess this hypothesis, we quantified the levels of VEGF in human respiratory epithelial lining fluid recovered by bronchoalveolar lavage from normal individuals. Strikingly, human respiratory epithelial lining fluid contains 11 +/- 5 ng/mL as quantified by ELISA, a 500-fold greater concentration than plasma (22 +/- 10 pg/mL, p Damocles sword" poised to induce lung endothelial permeability in conditions of acute lung injury when the integrity of the alveolar epithelial barrier is breached.

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

    Directory of Open Access Journals (Sweden)

    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

  6. Short communication: Early-lactation, but not mid-lactation, bovine lactoferrin preparation increases epithelial barrier integrity of Caco-2 cell layers.

    Science.gov (United States)

    Anderson, Rachel C; Bassett, Shalome A; Haggarty, Neill W; Gopal, Pramod K; Armstrong, Kelly M; Roy, Nicole C

    2017-02-01

    Bovine lactoferrin is an important milk protein with many health-promoting properties, including improving intestinal barrier integrity. Dysfunction of this barrier, commonly referred to as "leaky gut," has been linked to inflammatory and autoimmune diseases. With some processing techniques, lactoferrin isolated from milk collected at the start of the milking season (early lactation) may have lower purity than that isolated from milk collected during the rest of the milking season (mid-lactation) and could result in differences in bioactivity based on the stage of lactation. We compared reversed-phase HPLC chromatographs of early-lactation and mid-lactation preparations and found that both had large chromatograph peaks at the time predicted for lactoferrin. The notable difference between the 2 chromatographs was a much larger peak in the early-lactation lactoferrin sample that was determined to be angiogenin. Angiogenin was first identified due to its ability to induce new blood vessel formation, but is now known to be involved in numerous physiological processes. Then, we compared the effects of early-lactation and mid-lactation lactoferrin preparations in 2 bioassays: trans-epithelial electrical resistance (TEER), a measure of intestinal barrier integrity, and peripheral blood mononuclear cell cytokine secretion, a measure of immune-stimulatory properties. We found that early-lactation lactoferrin increased TEER across Caco-2 cell layers compared with control from 10 to 48 h, mid-lactation lactoferrin did not alter TEER. We also found that early-lactation lactoferrin reduced the amount of IL-8 produced by peripheral blood mononuclear cells (compared with those treated with control medium) to a greater extent than mid-lactation lactoferrin. A pro-inflammatory chemokine, IL-8 is also known to decrease barrier function. These results suggest that the decrease in IL-8 production in the presence of early-lactation lactoferrin may be the mechanism by which it increases

  7. Tight junction proteins contribute to barrier properties in human pleura.

    Science.gov (United States)

    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.

  8. 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.

  9. Microbiota-host interactions in irritable bowel syndrome: epithelial barrier, immune regulation and brain-gut interactions.

    Science.gov (United States)

    Hyland, Niall P; Quigley, Eamonn M M; Brint, Elizabeth

    2014-07-21

    Irritable bowel syndrome (IBS) is a common, sometimes debilitating, gastrointestinal disorder worldwide. While altered gut motility and sensation, as well as aberrant brain perception of visceral events, are thought to contribute to the genesis of symptoms in IBS, a search for an underlying aetiology has, to date, proven unsuccessful. Recently, attention has been focused on the microbiota as a possible factor in the pathogenesis of IBS. Prompted by a number of clinical observations, such as the recognition of the de novo development of IBS following enteric infections, as well as descriptions of changes in colonic bacterial populations in IBS and supported by clinical responses to interventions, such as antibiotics and probiotics, that modify the microbiota, various approaches have been taken to investigating the microbiota-host response in IBS, as well as in animal models thereof. From such studies a considerable body of evidence has accumulated to indicate the activation or upregulation of both factors involved in bacterial engagement with the host as well host defence mechanisms against bacteria. Alterations in gut barrier function, occurring in response, or in parallel, to changes in the microbiota, have also been widely described and can be seen to play a pivotal role in generating and sustaining host immune responses both within and beyond the gut. In this manner a plausible hypothesis, based on an altered microbiota and/or an aberrant host response, for the pathogenesis, of at least some instances of IBS, can be generated.

  10. Probiotic Bacteria Induce Maturation of Intestinal Claudin 3 Expression and Barrier Function

    Science.gov (United States)

    Patel, Ravi M.; Myers, Loren S.; Kurundkar, Ashish R.; Maheshwari, Akhil; Nusrat, Asma; Lin, Patricia W.

    2012-01-01

    An immature intestinal epithelial barrier may predispose infants and children to many intestinal inflammatory diseases, such as infectious enteritis, inflammatory bowel disease, and necrotizing enterocolitis. Understanding the factors that regulate gut barrier maturation may yield insight into strategies to prevent these intestinal diseases. The claudin family of tight junction proteins plays an important role in regulating epithelial paracellular permeability. Previous reports demonstrate that rodent intestinal barrier function matures during the first 3 weeks of life. We show that murine paracellular permeability markedly decreases during postnatal maturation, with the most significant change occurring between 2 and 3 weeks. Here we report for the first time that commensal bacterial colonization induces intestinal barrier function maturation by promoting claudin 3 expression. Neonatal mice raised on antibiotics or lacking the toll-like receptor adaptor protein MyD88 exhibit impaired barrier function and decreased claudin 3 expression. Furthermore, enteral administration of either live or heat-killed preparations of the probiotic Lactobacillus rhamnosus GG accelerates intestinal barrier maturation and induces claudin 3 expression. However, live Lactobacillus rhamnosus GG increases mortality. Taken together, these results support a vital role for intestinal flora in the maturation of intestinal barrier function. Probiotics may prevent intestinal inflammatory diseases by regulating intestinal tight junction protein expression and barrier function. The use of heat-killed probiotics may provide therapeutic benefit while minimizing adverse effects. PMID:22155109

  11. Cannabinoids mediate opposing effects on inflammation-induced intestinal permeability

    Science.gov (United States)

    Alhamoruni, A; Wright, KL; Larvin, M; O'Sullivan, SE

    2012-01-01

    BACKGROUND AND PURPOSE Activation of cannabinoid receptors decreases emesis, inflammation, gastric acid secretion and intestinal motility. The ability to modulate intestinal permeability in inflammation may be important in therapy aimed at maintaining epithelial barrier integrity. The aim of the present study was to determine whether cannabinoids modulate the increased permeability associated with inflammation in vitro. EXPERIMENTAL APPROACH Confluent Caco-2 cell monolayers were treated for 24 h with IFNγ and TNFα (10 ng·mL−1). Monolayer permeability was measured using transepithelial electrical resistance and flux measurements. Cannabinoids were applied either apically or basolaterally after inflammation was established. Potential mechanisms of action were investigated using antagonists for CB1, CB2, TRPV1, PPARγ and PPARα. A role for the endocannabinoid system was established using inhibitors of the synthesis and degradation of endocannabinoids. KEY RESULTS Δ9-Tetrahydrocannabinol (THC) and cannabidiol accelerated the recovery from cytokine-induced increased permeability; an effect sensitive to CB1 receptor antagonism. Anandamide and 2-arachidonylglycerol further increased permeability in the presence of cytokines; this effect was also sensitive to CB1 antagonism. No role for the CB2 receptor was identified in these studies. Co-application of THC, cannabidiol or a CB1 antagonist with the cytokines ameliorated their effect on permeability. Inhibiting the breakdown of endocannabinoids worsened, whereas inhibiting the synthesis of endocannabinoids attenuated, the increased permeability associated with inflammation. CONCLUSIONS AND IMPLICATIONS These findings suggest that locally produced endocannabinoids, acting via CB1 receptors play a role in mediating changes in permeability with inflammation, and that phytocannabinoids have therapeutic potential for reversing the disordered intestinal permeability associated with inflammation. LINKED ARTICLES This

  12. 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 bifidobacterium significantly decreased the production of IL-6 and TNF-α (P bifidobacterium pretreatment up-regulated occludin, claudin-3 and ZO-1 expression (P bifidobacterium decreased the incidence of NEC from 88 to 47% (P bifidobacterium treated rats (P bifidobacterium attenuated the increase in intestinal permeability (P bifidobacterium may protect against intestinal barrier dysfunction both in vitro and in NEC. This protective effect is associated with inhibition of proinflammatory cytokine secretion, suppression of zonulin protein release and improvement of intestinal TJ integrity.

  13. The Role of miR-330-3p/PKC-α Signaling Pathway in Low-Dose Endothelial-Monocyte Activating Polypeptide-II Increasing the Permeability of Blood-Tumor Barrier

    Directory of Open Access Journals (Sweden)

    Jiahui Liu

    2017-12-01

    Full Text Available This study was performed to determine whether EMAP II increases the permeability of the blood-tumor barrier (BTB by affecting the expression of miR-330-3p as well as its possible mechanisms. We determined the over-expression of miR-330-3p in glioma microvascular endothelial cells (GECs by Real-time PCR. Endothelial monocyte-activating polypeptide-II (EMAP-II significantly decreased the expression of miR-330-3p in GECs. Pre-miR-330-3p markedly decreased the permeability of BTB and increased the expression of tight junction (TJ related proteins ZO-1, occludin and claudin-5, however, anti-miR-330-3p had the opposite effects. Anti-miR-330-3p could enhance the effect of EMAP-II on increasing the permeability of BTB, however, pre-miR-330-3p partly reversed the effect of EMAP-II on that. Similarly, anti-miR-330-3p improved the effects of EMAP-II on increasing the expression levels of PKC-α and p-PKC-α in GECs and pre-miR-330-3p partly reversed the effects. MiR-330-3p could target bind to the 3′UTR of PKC-α. The results of in vivo experiments were similar to those of in vitro experiments. These suggested that EMAP-II could increase the permeability of BTB through inhibiting miR-330-3p which target negative regulation of PKC-α. Pre-miR-330-3p and PKC-α inhibitor decreased the BTB permeability and up-regulated the expression levels of ZO-1, occludin and claudin-5 while anti-miR-330-3p and PKC-α activator brought the reverse effects. Compared with EMAP-II, anti-miR-330-3p and PKC-α activator alone, the combination of the three combinations significantly increased the BTB permeability. EMAP-II combined with anti-miR-330-3p and PKCα activator could enhance the DOX’s effects on inhibiting the cell viabilities and increasing the apoptosis of U87 glioma cells. Our studies suggest that low-dose EMAP-II up-regulates the expression of PKC-α and increases the activity of PKC-α by inhibiting the expression of miR-330-3p, reduces the expression of ZO-1

  14. Larazotide acetate promotes tight junction assembly in epithelial cells.

    Science.gov (United States)

    Gopalakrishnan, Shobha; Tripathi, Amit; Tamiz, Amir P; Alkan, Sefik S; Pandey, Niranjan B

    2012-05-01

    Tight junctions (TJ) control paracellular permeability and apical-basolateral polarity of epithelial cells. Dysregulated permeability is associated with pathological conditions, such as celiac disease and inflammatory bowel disease. TJ formation is dependent on E-cadherin-mediated cell-cell adhesion and actin rearrangement, and is regulated by the Rho family GTPase and aPKC signaling pathways. Larazotide acetate, an 8-mer peptide and TJ modulator, inhibits TJ disassembly and dysfunction caused by endogenous and exogenous stimuli in intestinal epithelial cells. Here, we examined the effect of larazotide acetate on de novo TJ assembly using 2 different model systems. In MDCK cells, larazotide acetate promoted TJ assembly in a calcium switch assay. Larazotide acetate also promoted actin rearrangement, and junctional distribution of zonula occludens-1 (ZO-1), occludin, claudins, and E-cadherin. Larazotide acetate promoted TJ maturation and decreased paracellular permeability in "leaky" Caco-2 cells. Taken together, our data indicate that larazotide acetate enhances TJ assembly and barrier function by promoting actin rearrangement and redistribution of TJ and AJ proteins. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. The Microbiome Activates CD4 T-cell–mediated Immunity to Compensate for Increased Intestinal PermeabilitySummary

    Directory of Open Access Journals (Sweden)

    Karen L. Edelblum

    2017-09-01

    Full Text Available Background & Aims: Despite a prominent association, chronic intestinal barrier loss is insufficient to induce disease in human subjects or experimental animals. We hypothesized that compensatory mucosal immune activation might protect individuals with increased intestinal permeability from disease. We used a model in which intestinal barrier loss is triggered by intestinal epithelial-specific expression of constitutively active myosin light chain kinase (CA-MLCK. Here we asked whether constitutive tight junction barrier loss impacts susceptibility to enteric pathogens. Methods: Acute or chronic Toxoplasma gondii or Salmonella typhimurium infection was assessed in CA-MLCK transgenic or wild-type mice. Germ-free mice or those lacking specific immune cell populations were used to investigate the effect of microbial-activated immunity on pathogen translocation in the context of increased intestinal permeability. Results: Acute T gondii and S typhimurium translocation across the epithelial barrier was reduced in CA-MLCK mice. This protection was due to enhanced mucosal immune activation that required CD4+ T cells and interleukin 17A but not immunoglobulin A. The protective mucosal immune activation in CA-MLCK mice depended on segmented filamentous bacteria (SFB, because protection against early S typhimurium invasion was lost in germ-free CA-MLCK mice but could be restored by conventionalization with SFB-containing, not SFB-deficient, microbiota. In contrast, chronic S typhimurium infection was more severe in CA-MLCK mice, suggesting that despite activation of protective mucosal immunity, barrier defects ultimately result in enhanced disease progression. Conclusions: Increased epithelial tight junction permeability synergizes with commensal bacteria to promote intestinal CD4+ T-cell expansion and interleukin 17A production that limits enteric pathogen invasion. Keywords: Barrier Function, Tight Junction, Microbiota, CD4 T Cell, Mucosal Immunity

  16. Ultrathin Alumina Membranes as Scaffold for Epithelial Cell Culture from the Intestine of Rainbow Trout.

    Science.gov (United States)

    Drieschner, Carolin; Minghetti, Matteo; Wu, Songmei; Renaud, Philippe; Schirmer, Kristin

    2017-03-22

    Permeable membranes are indispensable for in vitro epithelial barrier models. However, currently available polymer-based membranes are low in porosity and relatively thick, resulting in a limited permeability and unrealistic culture conditions. In this study, we developed an ultrathin, nanoporous alumina membrane as novel cell culture interface for vertebrate cells, with focus on the rainbow trout (Onchorynchus mykiss) intestinal cell line RTgutGC. The new type of membrane is framed in a silicon chip for physical support and has a thickness of only 1 μm, with a porosity of 15% and homogeneous nanopores (Ø = 73 ± 21 nm). Permeability rates for small molecules, namely lucifer yellow, dextran 40, and bovine serum albumin, exceeded those of standard polyethylene terephthalate (PET) membranes by up to 27 fold. With the final goal to establish a representative model of the fish intestine for environmental toxicology, we engineered a simple culture setup, capable of testing the cellular response toward chemical exposure. Herein, cells were cultured in a monolayer on the alumina membranes and formed a polarized epithelium with apical expression of the tight junction protein ZO-1 within 14 days. Impedance spectroscopy, a noninvasive and real time electrical measurement, was used to determine cellular resistance during epithelial layer formation and chemical exposure to evaluate barrier functionality. Resistance values during epithelial development revealed different stages of epithelial maturity and were comparable with the in vivo situation. During chemical exposure, cellular resistance changed immediately when barrier tightness or cell viability was affected. Thus, our study demonstrates nanoporous alumina membranes as promising novel interface for alternative in vitro approaches, capable of allowing cell culture in a physiologically realistic manner and enabling high quality microscopy and sensitive measurement of cellular resistance.

  17. What mother is telling you : The messages encoded in milk-derived extracellular vesicles : Implications for the immune system and epithelial barrier function

    NARCIS (Netherlands)

    Zonneveld, M.I.|info:eu-repo/dai/nl/338042202

    2017-01-01

    Human milk assists the development of the neonatal intestinal epithelial mucosa. Human milk is composed of many bioactive macromolecular structures and it is under active investigation what the contribution of these structures is to the development of a healthy epithelial mucosa. One understudied

  18. Homeostasis of the gut barrier and potential biomarkers

    Science.gov (United States)

    Brummer, Robert J.; Derrien, Muriel; MacDonald, Thomas T.; Troost, Freddy; Cani, Patrice D.; Theodorou, Vassilia; Dekker, Jan; Méheust, Agnes; de Vos, Willem M.; Mercenier, Annick; Nauta, Arjen; Garcia-Rodenas, Clara L.

    2017-01-01

    The gut barrier plays a crucial role by spatially compartmentalizing bacteria to the lumen through the production of secreted mucus and is fortified by the production of secretory IgA (sIgA) and antimicrobial peptides and proteins. With the exception of sIgA, expression of these protective barrier factors is largely controlled by innate immune recognition of microbial molecular ligands. Several specialized adaptations and checkpoints are operating in the mucosa to scale the immune response according to the threat and prevent overreaction to the trillions of symbionts inhabiting the human intestine. A healthy microbiota plays a key role influencing epithelial barrier functions through the production of short-chain fatty acids (SCFAs) and interactions with innate pattern recognition receptors in the mucosa, driving the steady-state expression of mucus and antimicrobial factors. However, perturbation of gut barrier homeostasis can lead to increased inflammatory signaling, increased epithelial permeability, and dysbiosis of the microbiota, which are recognized to play a role in the pathophysiology of a variety of gastrointestinal disorders. Additionally, gut-brain signaling may be affected by prolonged mucosal immune activation, leading to increased afferent sensory signaling and abdominal symptoms. In turn, neuronal mechanisms can affect the intestinal barrier partly by activation of the hypothalamus-pituitary-adrenal axis and both mast cell-dependent and mast cell-independent mechanisms. The modulation of gut barrier function through nutritional interventions, including strategies to manipulate the microbiota, is considered a relevant target for novel therapeutic and preventive treatments against a range of diseases. Several biomarkers have been used to measure gut permeability and loss of barrier integrity in intestinal diseases, but there remains a need to explore their use in assessing the effect of nutritional factors on gut barrier function. Future studies

  19. Mechanisms of lung endothelial barrier disruption induced by cigarette smoke: role of oxidative stress and ceramides.

    Science.gov (United States)

    Schweitzer, Kelly S; Hatoum, Hadi; Brown, Mary Beth; Gupta, Mehak; Justice, Matthew J; Beteck, Besem; Van Demark, Mary; Gu, Yuan; Presson, Robert G; Hubbard, Walter C; Petrache, Irina

    2011-12-01

    The epithelial and endothelial cells lining the alveolus form a barrier essential for the preservation of the lung respiratory function, which is, however, vulnerable to excessive oxidative, inflammatory, and apoptotic insults. Whereas profound breaches in this barrier function cause pulmonary edema, more subtle changes may contribute to inflammation. The mechanisms by which cigarette smoke (CS) exposure induce lung inflammation are not fully understood, but an early alteration in the epithelial barrier function has been documented. We sought to investigate the occurrence and mechanisms by which soluble components of mainstream CS disrupt the lung endothelial cell barrier function. Using cultured primary rat microvascular cell monolayers, we report that CS induces endothelial cell barrier disruption in a dose- and time-dependent manner of similar magnitude to that of the epithelial cell barrier. CS exposure triggered a mechanism of neutral sphingomyelinase-mediated ceramide upregulation and p38 MAPK and JNK activation that were oxidative stress dependent and that, along with Rho kinase activation, mediated the endothelial barrier dysfunction. The morphological changes in endothelial cell monolayers induced by CS included actin cytoskeletal rearrangement, junctional protein zonula occludens-1 loss, and intercellular gap formation, which were abolished by the glutathione modulator N-acetylcysteine and ameliorated by neutral sphingomyelinase inhibition. The direct application of ceramide recapitulated the effects of CS, by disrupting both endothelial and epithelial cells barrier, by a mechanism that was redox and apoptosis independent and required Rho kinase activation. Furthermore, ceramide induced dose-dependent alterations of alveolar microcirculatory barrier in vivo, measured by two-photon excitation microscopy in the intact rat. In conclusion, soluble components of CS have direct endothelial barrier-disruptive effects that could be ameliorated by glutathione

  20. Increase in blood-brain barrier permeability, oxidative stress, and activated microglia in a rat model of blast-induced traumatic brain injury.

    Science.gov (United States)

    Readnower, Ryan D; Chavko, Mikulas; Adeeb, Saleena; Conroy, Michael D; Pauly, James R; McCarron, Richard M; Sullivan, Patrick G

    2010-12-01

    Traumatic brain injury (TBI) as a consequence of exposure to blast is increasingly prevalent in military populations, with the underlying pathophysiological mechanisms mostly unknown. In the present study, we utilized an air-driven shock tube to investigate the effects of blast exposure (120 kPa) on rat brains. Immediately following exposure to blast, neurological function was reduced. BBB permeability was measured using IgG antibody and evaluating its immunoreactivity in the brain. At 3 and 24 hr postexposure, there was a transient significant increase in IgG staining in the cortex. At 3 days postexposure, IgG immunoreactivity returned to control levels. Quantitative immunostaining was employed to determine the temporal course of brain oxidative stress following exposure to blast. Levels of 4-hydroxynonenal (4-HNE) and 3-nitrotyrosine (3-NT) were significantly increased at 3 hr postexposure and returned to control levels at 24 hr postexposure. The response of microglia to blast exposure was determined by autoradiographic localization of (3) H-PK11195 binding. At 5 days postexposure, increased binding was observed in the contralateral and ipsilateral dentate gyrus. These regions also displayed increased binding at 10 days postexposure; in addition to these regions there was increased binding in the contralateral ventral hippocampus and substantia nigra at this time point. By using antibodies against CD11b/c, microglia morphology characteristic of activated microglia was observed in the hippocampus and substantia nigra of animals exposed to blast. These results indicate that BBB breakdown, oxidative stress, and microglia activation likely play a role in the neuropathology associated with TBI as a result of blast exposure. Copyright © 2010 Wiley-Liss, Inc.

  1. Mast Cell Tryptase Reduces Junctional Adhesion Molecule-A (JAM-A) Expression in Intestinal Epithelial Cells: Implications for the Mechanisms of Barrier Dysfunction in Irritable Bowel Syndrome.

    LENUS (Irish Health Repository)

    Wilcz-Villega, Ewa M

    2013-07-01

    The objective of this study was to investigate how mast cell tryptase may influence intestinal permeability and tight junction (TJ) proteins in vitro and explore translation to irritable bowel syndrome (IBS).

  2. Zinc oxide nanoparticles as a substitute for zinc oxide or colistin sulfate: Effects on growth, serum enzymes, zinc deposition, intestinal morphology and epithelial barrier in weaned piglets.

    Science.gov (United States)

    Wang, Chao; Zhang, Ligen; Su, Weipeng; Ying, Zhixiong; He, Jintian; Zhang, Lili; Zhong, Xiang; Wang, Tian

    2017-01-01

    The objective of this study was to evaluate effects of zinc oxide nanoparticles (nano-ZnOs) as a substitute for colistin sulfate (CS) and/or zinc oxide (ZnO) on growth performance, serum enzymes, zinc deposition, intestinal morphology and epithelial barrier in weaned piglets. A total of 216 crossbred Duroc×(Landrace×Yorkshire) piglets weaned at 23 days were randomly assigned into 3 groups, which were fed with basal diets supplemented with 20 mg/kg CS (CS group), 20mg/kg CS+3000 mg/kg ZnO (CS+ZnO group), and 1200 mg/kg nano-ZnOs (nano-ZnO group) for 14 days. Results indicated that compared to CS group, supplementation of 1200 mg/kg nano-ZnOs (about 30 nm) significantly increased final body weight and average daily gain, and 3000 mg/kg ZnO plus colistin sulfate significantly increased average daily gain and decreased diarrhea rate in weaned piglets. There was no significant difference in growth performance and diarrhea rate between nano-ZnO and CS+ZnO groups. Supplementation of nano-ZnOs did not affect serum enzymes (glutamic oxalacetic transaminase, glutamic-pyruvic transaminase, and lactate dehydrogenase), but significantly increased plasma and tissue zinc concentrations (liver, tibia), improved intestinal morphology (increased duodenal and ileal villus length, crypt depth, and villus surface), enhanced mRNA expression of ZO-1 in ileal mucosa, and significantly decreased diamine oxidase activity in plasma, total aerobic bacterial population in MLN as compared to CS group. Effects of nano-ZnOs on serum enzymes, intestinal morphology, and mRNA expressions of tight junction were similar to those of high dietary ZnO plus colistin sulfate, while nano-ZnOs significantly reduced zinc concentrations of liver, tibia, and feces, and decreased total aerobic bacterial population in MLN as compared to CS+ZnO group. These results suggested that nano-ZnOs (1200 mg/kg) might be used as a substitute for colistin sulfate and high dietary ZnO in weaned piglets.

  3. Increased gut permeability and bacterial translocation after chronic chlorpyrifos exposure in rats.

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    Claire Joly Condette

    Full Text Available The epithelium's barrier function is crucial for maintaining homeostasis and preventing the passage of food antigens and luminal bacteria. This function is essentially subserved by tight junctions (TJs, multiprotein complexes located in the most apical part of the lateral membrane. Some gastrointestinal disease states are associated with elevated intestinal permeability to macromolecules. In a study on rats, we determined the influence of chronic, daily ingestion of chlorpyrifos (CPF, a pesticide that crosses the placental barrier during pre- and postnatal periods on intestinal permeability and TJ characteristics in the pups. Fluorescein isothiocyanate (FITC-dextran was used as a marker of paracellular transport and mucosal barrier dysfunction. Pups were gavaged with FITC-dextran solution and blood samples were collected every 30 min for 400 min and analyzed spectrofluorimetrically. At sacrifice, different intestinal segments were resected and prepared for analysis of the transcripts (qPCR and localization (using immunofluorescence of ZO-1, occludin and claudins (scaffolding proteins that have a role in the constitution of TJs. In rats that had been exposed to CPF in utero and after birth, we observed a progressive increase in FITC-dextran passage across the epithelial barrier from 210 to 325 min at day 21 after birth (weaning but not at day 60 (adulthood. At both ages, there were significant changes in intestinal TJ gene expression, with downregulation of ZO-1 and occludin and upregulation of claudins 1 and 4. In some intestinal segments, there were changes in the cellular localization of ZO-1 and claudin 4 immunostaining. Lastly, bacterial translocation to the spleen was also observed. The presence of CPF residues in food may disturb epithelial homeostasis in rats. Changes in TJ protein expression and localization may be involved in gut barrier dysfunction in this model. Uncontrolled passage of macromolecules and bacteria across the intestinal

  4. Endogenous IL-33 is highly expressed in mouse epithelial barrier tissues, lymphoid organs, brain, embryos, and inflamed tissues: in situ analysis using a novel Il-33-LacZ gene trap reporter strain.

    Science.gov (United States)

    Pichery, Mélanie; Mirey, Emilie; Mercier, Pascale; Lefrancais, Emma; Dujardin, Arnaud; Ortega, Nathalie; Girard, Jean-Philippe

    2012-04-01

    IL-33 (previously known as NF from high endothelial venules) is an IL-1 family cytokine that signals through the ST2 receptor and drives cytokine production in mast cells, basophils, eosinophils, invariant NKT and NK cells, Th2 lymphocytes, and type 2 innate immune cells (natural helper cells, nuocytes, and innate helper 2 cells). Little is known about endogenous IL-33; for instance, the cellular sources of IL-33 in mouse tissues have not yet been defined. In this study, we generated an Il-33-LacZ gene trap reporter strain (Il-33(Gt/Gt)) and used this novel tool to analyze expression of endogenous IL-33 in vivo. We found that the Il-33 promoter exhibits constitutive activity in mouse lymphoid organs, epithelial barrier tissues, brain, and embryos. Immunostaining with anti-IL-33 Abs, using Il-33(Gt/Gt) (Il-33-deficient) mice as control, revealed that endogenous IL-33 protein is highly expressed in mouse epithelial barrier tissues, including stratified squamous epithelia from vagina and skin, as well as cuboidal epithelium from lung, stomach, and salivary gland. Constitutive expression of IL-33 was not detected in blood vessels, revealing the existence of species-specific differences between humans and mice. Importantly, IL-33 protein was always localized in the nucleus of producing cells with no evidence for cytoplasmic localization. Finally, strong expression of the Il-33-LacZ reporter was also observed in inflamed tissues, in the liver during LPS-induced endotoxin shock, and in the lung alveoli during papain-induced allergic airway inflammation. Together, our findings support the possibility that IL-33 may function as a nuclear alarmin to alert the innate immune system after injury or infection in epithelial barrier tissues.

  5. Leukocyte-epithelial interactions.

    Science.gov (United States)

    Zen, Ke; Parkos, Charles A

    2003-10-01

    As a 'double-edged sword', neutrophil (polymorphonuclear leukocyte) migration across epithelial-lined organs is an important component of host defense, but it also results in epithelial pathophysiology and disease symptoms. There have been significant advances in better understanding the mechanisms of how leukocytes cross the vascular endothelium to exit the bloodstream; however, many of the mechanisms that govern polymorphonuclear leukocyte transepithelial migration are different and we are only just beginning to understand them. Recent findings include new junctional adhesion molecules and carbohydrate moieties as receptors for migrating neutrophils. In addition, new insights into leukocyte-epithelial signaling events have emerged that are beginning to shed light on the role of SIRP-CD47 interactions in regulating the rate of neutrophil transepithelial migration and how neutrophils modulate epithelial barrier function.

  6. Enhancement of blood-brain barrier permeability is required for intravenously administered virus neutralizing antibodies to clear an established rabies virus infection from the brain and prevent the development of rabies in mice.

    Science.gov (United States)

    Huang, Chien-Tsun; Li, Zhenguang; Huang, Ying; Zhang, Guoqing; Zhou, Ming; Chai, Qingqing; Wu, Hua; Fu, Zhen F

    2014-10-01

    Rabies virus (RABV) is a neurotropic virus that causes fatal disease in humans and animals. Currently there is no cure for rabies once clinical signs appear. It is believed that once RABV enters the central nervous system (CNS), virus neutralizing antibodies (VNAs) in the periphery cannot pass through the blood-brain barrier (BBB) and into the CNS. Furthermore, it has been hypothesized that VNAs produced in the CNS by invading B cells, rather than those produced in the periphery and then transported into the CNS, are important in clearing RABV from the CNS. In the present study, mouse serum containing VNA was administered intravenously into mice after infection with wild-type RABV. Our studies demonstrate that exogenous administration of VNAs is crucial in the clearance of RABV from the brain and prevent the development of rabies in both immunocompetent and immunocompromised mice as long as the BBB permeability remains enhanced. This present study therefore provides a foundation for the possibility of developing VNA therapy for clinical rabies in humans. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. 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

  8. Differential nephron HO-1 expression following glomerular epithelial cell injury.

    Science.gov (United States)

    Datta, Prasun K; Reddy, Sreenivas; Sharma, Mukut; Lianos, Elias A

    2006-01-01

    In proteinuria of glomerular origin there is upregulation of heme-oxygenase (HO), the rate-limiting enzyme of heme degradation, in the nephron in a segment-specific manner. To better characterize this phenomenon, we employed a model of proteinuria resulting from disruption of the glomerular capillary permeability barrier to protein by administration of the glomerular epithelial cell toxin puromycin aminonucleoside (PAN) to rats. In this model, we assessed nephron distribution of the expression of the inducible HO isoform, HO-1, and the role of free radicals in modulating HO-1 expression. Rats were injected with either vehicle (dimethyl sulfoxide) or PAN or the spin trap free radical stabilizer alpha-phenyl-N-tert butyl nitrone (PBN), or with both PAN and PBN. Ten days following the PAN injection, urine protein, creatinine, nitric oxide (NO) and malonyldialdehyde (MDA) were measured. Kidney sections and protein lysates were assessed for changes in HO-1 expression by immunohistochemistry and Western blot analysis. In control animals (DMSO or PBN alone) there was no proteinuria and very weak or absent HO-1 staining in nephron segments. PAN treatment induced proteinuria and increased urine MDA excretion. In these animals, there was a robust HO-1 expression mainly in tubules and in glomerular parietal but not visceral epithelial cells. Unilateral ureteral obstruction to interrupt glomerular filtration in animals treated with PAN abrogated tubular HO-1 expression in the kidney ipsilateral to the obstruction. Administration of PBN to PAN-treated animals reduced proteinuria and MDA excretion while it markedly augmented tubular HO-1 expression. This augmentation was prominent in tubular cells of the inner cortex/outer medulla. These observations indicate that upregulation of nephron HO-1 following disruption of the glomerular permeability barrier occurs at sites downstream of this barrier and is mediated by a filtered HO-1 inducer(s). Scavenging of free radicals potentiates

  9. Bifidobacterium lactis 420 and fish oil enhance intestinal epithelial integrity in Caco-2 cells.

    Science.gov (United States)

    Mokkala, Kati; Laitinen, Kirsi; Röytiö, Henna

    2016-03-01

    Increased intestinal permeability is a predisposing factor for low-grade inflammation-associated conditions, including obesity and type 2 diabetes. Dietary components may influence intestinal barrier integrity. We hypothesized that the dietary supplements Bifidobacterium lactis 420, Lactobacillus rhamnosus HN001, and fish oil have beneficial impacts on intestinal barrier integrity. In addition, we hypothesized that the coadministration of these components results in synergistic benefits to the integrity of the intestinal barrier. To study this, we investigated the impact of cell-free culture supernatant from dietary supplements B lactis 420 and L rhamnosus HN001, and fish oil, separately and in combination, on intestinal permeability in a CaCo-2 cell model. Administered separately, both B lactis 420 supernatant and fish oil significantly increased the integrity of the intestinal epithelial barrier, as determined by an increase in transepithelial electrical resistance (TEER), whereas L rhamnosus did not. The TEER increase with B lactis 420 was dose dependent. Interestingly, a combination of B lactis 420 supernatant and fish oil negated the increase in TEER of the single components. mRNA expression of tight junction proteins, measured by real-time quantitative polymerase chain reaction, was not altered, but the mRNA expression of myosin light chain kinase increased after fish oil treatment. To conclude, single dietary components, namely, B lactis 420 and fish oil, induced beneficial effects on intestinal barrier integrity in vitro, whereas a combination of 2 beneficial test compounds resulted in a null effect. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    NARCIS (Netherlands)

    P. Aparicio-Domingo (Patricia); M. Romera-Hernandez (Monica); 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

  11. Blood-brain barrier (BBB) toxicity and permeability assessment after L-(4-¹⁰Boronophenyl)alanine, a conventional B-containing drug for boron neutron capture therapy, using an in vitro BBB model.

    Science.gov (United States)

    Roda, E; Nion, S; Bernocchi, G; Coccini, T

    2014-10-02

    Since brain tumours are the primary candidates for treatment by Boron Neutron Capture Therapy, one major challenge in the selective drug delivery to CNS is the crossing of the blood-brain barrier (BBB). The present pilot study investigated (i) the transport of a conventional B-containing product (i.e., L-(4-(10)Boronophenyl)alanine, L-(10)BPA), already used in medicine but still not fully characterized regarding its CNS interactions, as well as (ii) the effects of the L-(10)BPA on the BBB integrity using an in vitro model, consisting of brain capillary endothelial cells co-cultured with glial cells, closely mimicking the in vivo conditions. The multi-step experimental strategy (i.e. Integrity test, Filter study, Transport assay) checked L-(10)BPA toxicity at 80 µg Boron equivalent/ml, and its ability to cross the BBB, additionally by characterizing the cytoskeletal and TJ's proteins by immunocytochemistry and immunoblotting. In conclusion, a lack of toxic effects of L-(10)BPA was demonstrated, nevertheless accompanied by cellular stress phenomena (e.g. vimentin expression modification), paralleled by a low permeability coefficient (0.39 ± 0.01 × 10(-3)cm min(-1)), corroborating the scarce probability that L-(10)BPA would reach therapeutically effective cerebral concentration. These findings emphasized the need for novel strategies aimed at optimizing boron delivery to brain tumours, trying to ameliorate the compound uptake or developing new targeted products suitable to safely and effectively treat head cancer. Thus, the use of in vitro BBB model for screening studies may provide a useful early safety assessment for new effective compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. West Nile virus-induced cell adhesion molecules on human brain microvascular endothelial cells regulate leukocyte adhesion and modulate permeability of the in vitro blood-brain barrier model.

    Directory of Open Access Journals (Sweden)

    Kelsey Roe

    Full Text Available Characterizing the mechanisms by which West Nile virus (WNV causes blood-brain barrier (BBB disruption, leukocyte infiltration into the brain and neuroinflammation is important to understand the pathogenesis of WNV encephalitis. Here, we examined the role of endothelial cell adhesion molecules (CAMs in mediating the adhesion and transendothelial migration of leukocytes across human brain microvascular endothelial cells (HBMVE. Infection with WNV (NY99 strain significantly induced ICAM-1, VCAM-1, and E-selectin in human endothelial cells and infected mice brain, although the levels of their ligands on leukocytes (VLA-4, LFA-1and MAC-1 did not alter. The permeability of the in vitro BBB model increased dramatically following the transmigration of monocytes and lymphocytes across the models infected with WNV, which was reversed in the presence of a cocktail of blocking antibodies against ICAM-1, VCAM-1, and E-selectin. Further, WNV infection of HBMVE significantly increased leukocyte adhesion to the HBMVE monolayer and transmigration across the infected BBB model. The blockade of these CAMs reduced the adhesion and transmigration of leukocytes across the infected BBB model. Further, comparison of infection with highly neuroinvasive NY99 and non-lethal (Eg101 strain of WNV demonstrated similar level of virus replication and fold-increase of CAMs in HBMVE cells suggesting that the non-neuropathogenic response of Eg101 is not because of its inability to infect HBMVE cells. Collectively, these results suggest that increased expression of specific CAMs is a pathological event associated with WNV infection and may contribute to leukocyte infiltration and BBB disruption in vivo. Our data further implicate that strategies to block CAMs to reduce BBB disruption may limit neuroinflammation and virus-CNS entry via 'Trojan horse' route, and improve WNV disease outcome.

  13. West Nile virus-induced cell adhesion molecules on human brain microvascular endothelial cells regulate leukocyte adhesion and modulate permeability of the in vitro blood-brain barrier model.

    Science.gov (United States)

    Roe, Kelsey; Orillo, Beverly; Verma, Saguna

    2014-01-01

    Characterizing the mechanisms by which West Nile virus (WNV) causes blood-brain barrier (BBB) disruption, leukocyte infiltration into the brain and neuroinflammation is important to understand the pathogenesis of WNV encephalitis. Here, we examined the role of endothelial cell adhesion molecules (CAMs) in mediating the adhesion and transendothelial migration of leukocytes across human brain microvascular endothelial cells (HBMVE). Infection with WNV (NY99 strain) significantly induced ICAM-1, VCAM-1, and E-selectin in human endothelial cells and infected mice brain, although the levels of their ligands on leukocytes (VLA-4, LFA-1and MAC-1) did not alter. The permeability of the in vitro BBB model increased dramatically following the transmigration of monocytes and lymphocytes across the models infected with WNV, which was reversed in the presence of a cocktail of blocking antibodies against ICAM-1, VCAM-1, and E-selectin. Further, WNV infection of HBMVE significantly increased leukocyte adhesion to the HBMVE monolayer and transmigration across the infected BBB model. The blockade of these CAMs reduced the adhesion and transmigration of leukocytes across the infected BBB model. Further, comparison of infection with highly neuroinvasive NY99 and non-lethal (Eg101) strain of WNV demonstrated similar level of virus replication and fold-increase of CAMs in HBMVE cells suggesting that the non-neuropathogenic response of Eg101 is not because of its inability to infect HBMVE cells. Collectively, these results suggest that increased expression of specific CAMs is a pathological event associated with WNV infection and may contribute to leukocyte infiltration and BBB disruption in vivo. Our data further implicate that strategies to block CAMs to reduce BBB disruption may limit neuroinflammation and virus-CNS entry via 'Trojan horse' route, and improve WNV disease outcome.

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

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    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.

  15. The role of barrier function of mucous membranes in allergic diseases and sublingual allergen-specific immunotherapy

    Directory of Open Access Journals (Sweden)

    Oksana M. Kurbacheva

    2017-01-01

    Full Text Available Currently one of the factors of allergy predisposition is the increase in barrier permeability of the mucous membranes of the respiratory system and the gastrointestinal tract (GIT. It defines the probability of an emergence of an allergic response. To understand the mechanisms of the interaction of the mucous membranes of different systems that explain their common function is undoubtedly necessary for discussion of this problem. The features of microbiome influence and the changes of the microbiome state during the formation of the immune response to the contact with allergens are of particular interest. The structure of the epithelial barrier of the airwaysand GIT, and mechanisms of allergen transport through barrier systems with the subsequent interaction with the cells (? associated with barrier fabrics have been considered. The possible role of the barrier function of mucous membranes in conducting sublingual allergen-specific immunotherapy (SLIT is discussed. 

  16. Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D.

    Science.gov (United States)

    Anabazhagan, Arivarasu N; Chatterjee, Ishita; Priyamvada, Shubha; Kumar, Anoop; Tyagi, Sangeeta; Saksena, Seema; Alrefai, Waddah A; Dudeja, Pradeep K; Gill, Ravinder K

    2017-03-16

    The intestinal epithelium has important transport and barrier functions that play key roles in normal physiological functions of the body while providing a barrier to foreign particles. Impaired epithelial transport (ion, nutrient, or drugs) has been associated with many diseases and can have consequences that extend beyond the normal physiological functions of the transporters, such as by influencing epithelial integrity and the gut microbiome. Understanding the function and regulation of transport proteins is critical for the development of improved therapeutic interventions. The biggest challenge in the study of epithelial transport is developing a suitable model system that recapitulates important features of the native intestinal epithelial cells. Several in vitro cell culture models, such as Caco-2, T-84, and HT-29-Cl.19A cells are typically used in epithelial transport research. These cell lines represent a reductionist approach to modeling the epithelium and have been used in many mechanistic studies, including their examination of epithelial-microbial interactions. However, cell monolayers do not accurately reflect cell-cell interactions and the in vivo microenvironment. Cells grown in 3D have shown to be promising models for drug permeability studies. We show that Caco-2 cells in 3D can be used to study epithelial transporters. It is also important that studies in Caco-2 cells are complemented with other models to rule out cell specific effects and to take into account the complexity of the native intestine. Several methods have been previously used to assess the functionality of transporters, such as everted sac and uptake in isolated epithelial cells or in isolated plasma membrane vesicles. Taking into consideration the challenges in the field with respect to models and the measurement of transport function, we demonstrate here a protocol to grow Caco-2 cells in 3D and describe the use of an Ussing chamber as an effective approach to measure serotonin

  17. Modulation of Human Airway Barrier Functions during Burkholderia thailandensis and Francisella tularensis Infection Running Title: Airway Barrier Functions during Bacterial Infections

    Directory of Open Access Journals (Sweden)

    Cornelia Blume

    2016-08-01

    Full Text Available The bronchial epithelium provides protection against pathogens from the inhaled environment through the formation of a highly-regulated barrier. In order to understand the pulmonary diseases melioidosis and tularemia caused by Burkholderia thailandensis and Fransicella tularensis, respectively, the barrier function of the human bronchial epithelium were analysed. Polarised 16HBE14o- or differentiated primary human bronchial epithelial cells (BECs were exposed to increasing multiplicities of infection (MOI of B. thailandensis or F. tularensis Live Vaccine Strain and barrier responses monitored over 24–72 h. Challenge of polarized BECs with either bacterial species caused an MOI- and time-dependent increase in ionic permeability, disruption of tight junctions, and bacterial passage from the apical to the basolateral compartment. B. thailandensis was found to be more invasive than F. tularensis. Both bacterial species induced an MOI-dependent increase in TNF-α release. An increase in ionic permeability and TNF-α release was induced by B. thailandensis in differentiated BECs. Pretreatment of polarised BECs with the corticosteroid fluticasone propionate reduced bacterial-dependent increases in ionic permeability, bacterial passage, and TNF-α release. TNF blocking antibody Enbrel® reduced bacterial passage only. BEC barrier properties are disrupted during respiratory bacterial infections and targeting with corticosteroids or anti-TNF compounds may represent a therapeutic option.

  18. New Trends in Quantitative Assessment of the Corneal Barrier Function

    Directory of Open Access Journals (Sweden)

    Anton Guimerà

    2014-05-01

    Full Text Available The cornea is a very particular tissue due to its transparency and its barrier function as it has to resist against the daily insults of the external environment. In addition, maintenance of this barrier function is of crucial importance to ensure a correct corneal homeostasis. Here, the corneal epithelial permeability has been assessed in vivo by means of non-invasive tetrapolar impedance measurements, taking advantage of the huge impact of the ion fluxes in the passive electrical properties of living tissues. This has been possible by using a flexible sensor based in SU-8 photoresist. In this work, a further analysis focused on the validation of the presented sensor is performed by monitoring the healing process of corneas that were previously wounded. The obtained impedance measurements have been compared with the damaged area observed in corneal fluorescein staining images. The successful results confirm the feasibility of this novel method, as it represents a more sensitive in vivo and non-invasive test to assess low alterations of the epithelial permeability. Then, it could be used as an excellent complement to the fluorescein staining image evaluation.

  19. 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.

  20. Gut barrier in health and disease: focus on childhood.

    Science.gov (United States)

    Viggiano, D; Ianiro, G; Vanella, G; Bibbò, S; Bruno, G; Simeone, G; Mele, G

    2015-01-01

    The gut barrier is a functional unit, organized as a multi-layer system, made up of two main components: a physical barrier surface, which prevents bacterial adhesion and regulates paracellular diffusion to the host tissues, and a deep functional barrier, that is able to discriminate between pathogens and commensal microorganisms, organizing the immune tolerance and the immune response to pathogens. Other mechanisms, such as gastric juice and pancreatic enzymes (which both have antibacterial properties) participate in the luminal integrity of the gut barrier. From the outer layer to the inner layer, the physical barrier is composed of gut microbiota (that competes with pathogens to gain space and energy resources, processes the molecules necessary to mucosal integrity and modulates the immunological activity of deep barrier), mucus (which separates the intraluminal content from more internal layers and contains antimicrobial products and secretory IgA), epithelial cells (which form a physical and immunological barrier) and the innate and adaptive immune cells forming the gut-associated lymphoid tissue (which is responsible for antigen sampling and immune responses). Disruption of the gut barrier has been associated with many gastrointestinal diseases, but also with extra-intestinal pathological condition, such as type 1 diabetes mellitus, allergic diseases or autism spectrum disorders. The maintenance of a healthy intestinal barrier is therefore of paramount importance in children, for both health and economic reasons. Many drugs or compounds used in the treatment of gastrointestinal disorders act through the restoration of a normal intestinal permeability. Several studies have highlighted the role of probiotics in the modulation and reduction of intestinal permeability, considering the strong influence of gut microbiota in the modulation of the function and structure of gut barrier, but also on the immune response of the host. To date, available weapons for the

  1. Long-term performance of elemental iron and hydroxyapatite for uranium retention in permeable reactive barriers used for groundwater remediation; Langzeitverhalten von elementarem Eisen und Hydroxylapatit zur Uranrueckhaltung in permeablen reaktiven Waenden bei der Grundwassersanierung

    Energy Technology Data Exchange (ETDEWEB)

    Biermann, V.

    2007-11-21

    Elemental iron (Fe{sup 0}) and hydroxyapatite (HAP) were evaluated as reactive mate-rials for use in permeable reactive barriers (PRBs) to remove uranium from conta-minated groundwater. Special attention was given to the long-term performance of the materials, which was investigated by means of column tests with a duration of up to 30 months using two different artificial groundwaters (AGW) with varying composition and uranium concentration. The interaction of the materials with AGW was studied in column tests using {sup 237}U as a radiotracer to monitor the movement of the contamination front through the columns. The tested materials were shredded cast iron (granulated grey cast iron, 0.3 - 1.3 mm) supplied by Gotthard Mayer, Rheinfelden, Germany, and food quality grade hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}OH, 99 % < 0.42 mm) supplied by Che-mische Fabrik Budenheim CFB, Germany. Both materials exhibited uranium retention of more than 99.9% and sorption capacities of up to 28.3 mg U/g HAP and more than 38.4 mg U/g Fe{sup 0} (AGW with 9.6 mg U/L and low bicarbonate content of 120 mg/L). No breakthrough was observed for the Fe{sup 0} columns with effluent uranium con-centrations being below the detection limit of 10 {mu}g/L after treating more than 2,000 pore volumes (PV) and no uranium could be leached from loaded Fe{sup 0} columns with 200 PV of uranium free AGW. However, columns with high Fe{sup 0} content ({>=} 50%) suffered from severe loss of permeability when AGW with {>=} 320 mg/L bicarbonate was used. In the HAP columns a breakthrough occurred with effluent uranium concentrations > 15 {mu}g/l after treating 1,240 PV (10% and 50% breakthrough after 1,460 PV and 2,140 PV respectively). 12.2% of the accu-mulated uranium could be desorbed again with 840 PV of uranium free AGW. Adsorption was found to be the dominant reaction mechanism for uranium and HAP. Image analysis of high uranium content samples showed uranium and phosphate bearing crystals growing

  2. Effects of chlorhexidine on the structure and permeability of hamster cheek pouch mucosa

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-10-01

    This study examined the effects of chlorhexidine (CHD) on the clinical appearance, morphology, and in vitro permeability of hamster cheek pouch mucosa. The cheek pouches were treated daily for 3 weeks with topical applications of saline, 0.2% CHD, or 2.0% CHD. Treatment with 2.0% CHD resulted in the formation of discrete white lesions in every animal in the group, whereas no changes were identified in any animal treated with 0.2% CHD or saline. Upon microscopic examination it was determined that treatment with 2.0% CHD resulted in a statistically significant increase in epithelial thickness, when compared to the other groups, and the lesions were found to consist of hyperplastic areas of epithelium with associated inflammatory cell accumulations. Daily treatments with 2.0% CHD, 0.2% CHD or saline had no effect on the very low permeability of cheek pouch mucosa to /sup 14/C-CHD. However, treatment with 2.0% CHD resulted in decreased permeability to /sup 3/H/sub 2/O when compared to the other groups. Treatment with 2.0% CHD also resulted in a thickened permeability barrier, as determined using a tracer, horseradish peroxidase. It is concluded that topical applications of 0.2% T CHD have no detectable effect on cheek-pouch mucosa while applications of 2.0% CHD result in hyperplasia and a decrease in mucosal permeability. Results suggest that CHD should be used with caution clinically and at a concentration of 0.2% or less.

  3. Blood-brain barrier permeability of normal-appearing white matter in patients with vestibular schwannoma: A new hybrid approach for analysis of T1 -W DCE-MRI.

    Science.gov (United States)

    Li, Ka-Loh; Zhu, Xiaoping; Zhao, Sha; Jackson, Alan

    2017-07-01

    To develop and assess a "hybrid" method that combines a first-pass analytical approach and the Patlak plot (PP) to improve assessment of low blood-brain barrier permeability from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data. Seven patients with vestibular schwannoma were enrolled. T1 -W DCE imaging was acquired on a 1.5T scanner. Normal-appearing white matter (NAWM) was divided into four regions of interest (ROIs) based on the magnitude of changes in longitudinal relaxation rate (ΔR1) after gadolinium administration. Kinetic analysis of ROI-averaged contrast agent concentration curves was performed using both the conventional PP and the hybrid method. Computer simulated uptake curves that resemble those from NAWM were analyzed with both methods. Percent deviations (PD) of the "measured" values from the "true" values were calculated to evaluate accuracy and precision of the two methods. The simulation showed that, at a noise level of 4% (a noise level similar to the in vivo data) and using a signal intensity (SI) averaging scheme, the new hybrid method achieved a PD of 0.9 ± 2.7% for vp , and a PD of -5.4 ± 5.9% for Ktrans . In comparison, the PP method obtained a PD of 3.6 ± 11.3% for vp , and -8.3 ± 12.8% for Ktrans . One-way analyses of variance (ANOVAs) showed significant variations from the four WM regions (P < 10-15 for ΔR1; P < 10-6 for Ktrans ; P < 10-4 for vp ). Both computer simulation and in vivo studies demonstrate improved reliability in vp and Ktrans estimates with the hybrid method. 3 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:79-93. © 2017 The Authors Journal of Magnetic Resonance Imaging published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  4. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model.

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J; Damby, David E; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J D

    2016-12-12

    There are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles. A sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm(2), respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively. The combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all three cell types of

  5. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J.; Damby, David; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J. D.

    2016-01-01

    BackgroundThere are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles.MethodsA sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm2, respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively.ResultsThe combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all

  6. Development in NMR spiral imaging and application to the assessment of the permeability of the blood-brain barrier on 2 models of brain tumors; Developpements en imagerie RMN spirale et application a la caracterisation de la permeabilite de la barriere hemato-encephalique sur deux modeles de tumeurs intracerebrales

    Energy Technology Data Exchange (ETDEWEB)

    Beaumont, M

    2007-12-15

    The results presented in this work were obtained as part of methodological developments in magnetic resonance imaging. First of all, the setting of the rapid imaging technique using a k-space sampling scheme along a variable density spiral is described. Numerical simulations were used to optimize the acquisitions parameters and to compare different reconstruction techniques. An original approach to calibrate the k-space trajectory was proposed. Then, spiral imaging was used to implement a method to measure the blood brain barrier permeability to Gd-DOTA. This protocol was combined to blood volume and vessel size index measurements using Sinerem. The results obtained highlighted differences between the microvascular parameters measured on C6 and RG2 tumor models. The presence of Sinerem induces a mean decrease of the transfer constant across the vascular wall (Ktrans), in the tumor, of 24 per cent. This study also showed extravasation of the Sinerem, during the first two hours after the product injection, only in the RG2 tumors. (author)

  7. Pore-forming virulence factors of Staphylococcus aureus destabilize epithelial barriers-effects of alpha-toxin in the early phases of airway infection

    Directory of Open Access Journals (Sweden)

    Jan-Peter Hildebrandt

    2015-09-01

    Full Text Available Staphylococcus aureus (S. aureus is a human commensal and an opportunistic pathogen that may affect the gastrointestinal tract, the heart, bones, skin or the respiratory tract. S. aureus is frequently involved in hospital- or community-acquired lung infections. The pathogenic potential is associated with its ability to secrete highly effective virulence factors. Among these, the pore-forming toxins Panton-Valentine leukocidin (PVL and hemolysin A (Hla are the important virulence factors determining the prognosis of pneumonia cases. This review focuses on the structure and the functions of S. aureus hemolysin A and its sub-lethal effects on airway epithelial cells. The hypothesis is developed that Hla may not just be a tissue-destructive agent providing the bacteria with host-derived nutrients, but may also play complex roles in the very early stages of interactions of bacteria with healthy airways, possibly paving the way for establishing acute infections.

  8. Permeability prediction in chalks

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Prasad, Manika

    2011-01-01

    prediction, so we have investigated the use of velocity data to predict permeability. The compressional velocity fromwireline logs and core plugs of the chalk reservoir in the South Arne field, North Sea, has been used for this study. We compared various methods of permeability prediction from velocities......-permeability relationships were replaced by relationships between velocity of elastic waves and permeability using laboratory data, and the relationships were then applied to well-log data. We found that the permeability prediction in chalk and possibly other sediments with large surface areas could be improved...

  9. Film Permeability Determination Using Static Permeability Cells

    Science.gov (United States)

    The permeability of tarps to soil fumigant pesticides varies depending on the active ingredient chemical: dimethyl disulfide (DMDS), methyl bromide, chloropicrin, or other. The diffusion rate can be represented by the mass transfer coefficient (MTC).

  10. Estimation of soil permeability

    Directory of Open Access Journals (Sweden)

    Amr F. Elhakim

    2016-09-01

    Full Text Available Soils are permeable materials because of the existence of interconnected voids that allow the flow of fluids when a difference in energy head exists. A good knowledge of soil permeability is needed for estimating the quantity of seepage under dams and dewatering to facilitate underground construction. Soil permeability, also termed hydraulic conductivity, is measured using several methods that include constant and falling head laboratory tests on intact or reconstituted specimens. Alternatively, permeability may be measured in the field using insitu borehole permeability testing (e.g. [2], and field pumping tests. A less attractive method is to empirically deduce the coefficient of permeability from the results of simple laboratory tests such as the grain size distribution. Otherwise, soil permeability has been assessed from the cone/piezocone penetration tests (e.g. [13,14]. In this paper, the coefficient of permeability was measured using field falling head at different depths. Furthermore, the field coefficient of permeability was measured using pumping tests at the same site. The measured permeability values are compared to the values empirically deduced from the cone penetration test for the same location. Likewise, the coefficients of permeability are empirically obtained using correlations based on the index soil properties of the tested sand for comparison with the measured values.

  11. Optimization of micro-fabricated porous membranes for intestinal epithelial cell culture and in vitro modeling of the human intestinal barrier

    Science.gov (United States)

    Nair Gourikutty Sajay, Bhuvanendran; Yin, Chiam Su; Ramadan, Qasem

    2017-12-01

    In vitro modeling of organs could provide a controlled platform for studying physiological events and has great potential in the field of pharmaceutical development. Here, we describe the characterization of in vitro modeling of the human intestinal barrier mimicked using silicon porous membranes as a substrate. To mimic an intestinal in vivo setup as closely as possible, a porous substrate is required in a dynamic environment for the cells to grow rather than a static setup with an impermeable surface such as a petri dish. In this study, we focus on the detailed characterization of Caco-2 cells cultured on a silicon membrane with different pore sizes as well as the effect of dynamic fluid flow on the model. The porous silicon membrane together with continuous perfusion of liquid applying shear stress on the cells enhances the differentiation of polarized cells by providing access to the both their basal and apical surfaces. Membranes with pore sizes of 0.5–3 µm were used and a shear stress of ~0.03 dyne cm‑2 was created by applying a low flow rate of 20 nl s‑1. By providing these optimized conditions, cells were able to differentiate with columnar morphology, which developed microvilli structures on their apical side and tight junctions between adjacent cells like those in a healthy human intestinal barrier. In this setup, it is possible to study the important cellular functions of the intestine such as transport, absorption and secretion, and thus this model has great potential in drug screening.

  12. Glycomacropeptide Reduces Intestinal Epithelial Cell Barrier Dysfunction and Adhesion of Entero-Hemorrhagic and Entero-Pathogenic Escherichia coli in Vitro

    Directory of Open Access Journals (Sweden)

    Shane Feeney

    2017-10-01

    Full Text Available In recent years, the potential of glycosylated food components to positively influence health has received considerable attention. Milk is a rich source of biologically active glycoconjugates which are associated with antimicrobial, immunomodulatory, anti-adhesion, anti-inflammatory and prebiotic properties. Glycomacropeptide (GMP is the C-terminal portion of kappa-casein that is released from whey during cheese-making by the action of chymosin. Many of the biological properties associated with GMP, such as anti-adhesion, have been linked with the carbohydrate portion of the protein. In this study, we investigated the ability of GMP to inhibit the adhesion of a variety of pathogenic Escherichia coli strains to HT-29 and Caco-2 intestinal cell lines, given the importance of E. coli in causing bacterial gastroenteritis. GMP significantly reduced pathogen adhesion, albeit with a high degree of species specificity toward enteropathogenic E. coli (EPEC strains O125:H32 and O111:H2 and enterohemorrhagic E. coli (EHEC strain 12900 O157:H7. The anti-adhesive effect resulted from the interaction of GMP with the E. coli cells and was also dependent on GMP concentration. Pre-incubation of intestinal Caco-2 cells with GMP reduced pathogen translocation as represented by a decrease in transepithelial electrical resistance (TEER. Thus, GMP is an effective in-vitro inhibitor of adhesion and epithelial injury caused by E. coli and may have potential as a biofunctional ingredient in foods to improve gastrointestinal health.

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

    Science.gov (United States)

    Fenyvesi, Ferenc; Réti-Nagy, Katalin; Bacsó, Zsolt; Gutay-Tóth, Zsuzsanna; Malanga, Milo; Fenyvesi, Éva; Szente, Lajos; Váradi, Judit; Ujhelyi, Zoltán; Fehér, Pálma; Szabó, Gábor; Vecsernyés, Miklós; Bácskay, Ildikó

    2014-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Cryptococcus–Epithelial Interactions

    Directory of Open Access Journals (Sweden)

    Leanne M. Taylor-Smith

    2017-10-01

    Full Text Available The fungal pathogen, Cryptococcus neoformans, causes devastating levels of morbidity and mortality. Infections with this fungus tend to be predominantly in immunocompromised individuals, such as those with HIV. Infections initiate with inhalation of cryptococcal cells and entry of the pathogen into the lungs. The bronchial epithelial cells of the upper airway and the alveolar epithelial cells of the lower airway are likely to be the first host cells that Cryptococcus engage with. Thus the interaction of cryptococci and the respiratory epithelia will be the focus of this review. C. neoformans has been shown to adhere to respiratory epithelial cells, although if the role of the capsule is in aiding or hindering this adhesion is debatable. The epithelia are also able to react to cryptococci with the release of cytokines and chemokines to start the immune response to this invading pathogen. The activity of surfactant components that line this mucosal barrier towards Cryptococcus and the metabolic and transcriptional reaction of cryptococci when encountering epithelial cells will also be discussed.

  16. 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.

  17. 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

  18. Myosin light chain kinase mediates intestinal barrier dysfunction via occludin endocytosis during anoxia/reoxygenation injury.

    Science.gov (United States)

    Jin, Younggeon; Blikslager, Anthony T

    2016-12-01

    Intestinal anoxia/reoxygenation (A/R) injury induces loss of barrier function followed by epithelial repair. Myosin light chain kinase (MLCK) has been shown to alter barrier function via regulation of interepithelial tight junctions, but has not been studied in intestinal A/R injury. We hypothesized that A/R injury would disrupt tight junction barrier function via MLCK activation and myosin light chain (MLC) phosphorylation. Caco-2BBe1 monolayers were subjected to anoxia for 2 h followed by reoxygenation in 21% O 2 , after which barrier function was determined by measuring transepithelial electrical resistance (TER) and FITC-dextran flux. Tight junction proteins and MLCK signaling were assessed by Western blotting, real-time PCR, or immunofluorescence microscopy. The role of MLCK was further investigated with select inhibitors (ML-7 and peptide 18) by using in vitro and ex vivo models. Following A/R injury, there was a significant increase in paracellular permeability compared with control cells, as determined by TER and dextran fluxes (P endocytosis caused by A/R injury. Application of MLCK inhibitors to ischemia-injured porcine ileal mucosa induced significant increases in TER and reduced mucosal-to-serosal fluxes of 3 H-labeled mannitol. These data suggest that MLCK-induced occludin endocytosis mediates intestinal epithelial barrier dysfunction during A/R injury. Our results also indicate that MLCK-dependent occludin regulation may be a target for the therapeutic treatment of ischemia/reperfusion injury. Copyright © 2016 the American Physiological Society.

  19. Regulation of the Intestinal Barrier Function by Host Defense Peptides.

    Science.gov (United States)

    Robinson, Kelsy; Deng, Zhuo; Hou, Yongqing; Zhang, Guolong

    2015-01-01

    Intestinal barrier function is achieved primarily through regulating the synthesis of mucins and tight junction (TJ) proteins, which are critical for maintaining optimal gut health and animal performance. An aberrant expression of TJ proteins results in increased paracellular permeability, leading to intestinal and systemic disorders. As an essential component of innate immunity, host defense peptides (HDPs) play a critical role in mucosal defense. Besides broad-spectrum antimicrobial activities, HDPs promotes inflammation resolution, endotoxin neutralization, wound healing, and the development of adaptive immune response. Accumulating evidence has also indicated an emerging role of HDPs in barrier function and intestinal homeostasis. HDP deficiency in the intestinal tract is associated with barrier dysfunction and dysbiosis. Several HDPs were recently shown to enhance mucosal barrier function by directly inducing the expression of multiple mucins and TJ proteins. Consistently, dietary supplementation of HDPs often leads to an improvement in intestinal morphology, production performance, and feed efficiency in livestock animals. This review summarizes current advances on the regulation of epithelial integrity and homeostasis by HDPs. Major signaling pathways mediating HDP-induced mucin and TJ protein synthesis are also discussed. As an alternative strategy to antibiotics, supplementation of exogenous HDPs or modulation of endogenous HDP synthesis may have potential to improve intestinal barrier function and animal health and productivity.

  20. Regulation of the intestinal barrier function by host defense peptides

    Directory of Open Access Journals (Sweden)

    Kelsy eRobinson

    2015-11-01

    Full Text Available Intestinal barrier function is achieved primarily through regulating the synthesis of mucins and tight junction proteins, which are critical for maintaining optimal gut health and animal performance. An aberrant expression of tight junction proteins results in increased paracellular permeability, leading to intestinal and systemic disorders. As an essential component of innate immunity, host defense peptides (HDPs play a critical role in mucosal defense. Besides broad-spectrum antimicrobial activities, HDPs promotes inflammation resolution, endotoxin neutralization, wound healing, and the development of adaptive immune response. Accumulating evidence has also indicated an emerging role of HDPs in barrier function and intestinal homeostasis. HDP deficiency in the intestinal tract is associated with barrier dysfunction and dysbiosis. Several HDPs were recently shown to enhance mucosal barrier function by directly inducing the expression of multiple mucins and tight junction proteins. Consistently, dietary supplementation of HDPs often leads to an improvement in intestinal morphology, production performance, and feed efficiency in livestock animals. This review summarizes current advances on the regulation of epithelial integrity and homeostasis by HDPs. Major signaling pathways mediating HDP-induced mucin and tight junction protein synthesis are also discussed. As an alternative strategy to antibiotics, supplementation of exogenous HDPs or modulation of endogenous HDP synthesis may have potential to improve intestinal barrier function and animal health and productivity.

  1. 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....

  2. The role of CB1 in intestinal permeability and inflammation.

    Science.gov (United States)

    Karwad, Mustafa A; Couch, Daniel G; Theophilidou, Elena; Sarmad, Sarir; Barrett, David A; Larvin, Michael; Wright, Karen L; Lund, Jonathan N; O'Sullivan, Saoirse E

    2017-08-01

    The endocannabinoid system has previously been shown to play a role in the permeability and inflammatory response of the human gut. The goal of our study was to determine the effects of endogenous anandamide (AEA) and 2-arachidonoyl glycerol (2-AG) on the permeability and inflammatory response of intestinal epithelium under normal, inflammatory, and hypoxic conditions. Human intestinal mucosa was modeled using Caco-2 cells. Human tissue was collected from planned colorectal resections. Accumulation of AEA and 2-AG was achieved by inhibiting their metabolizing enzymes URB597 (a fatty acid amide hydrolase inhibitor) and JZL184 (a monoacylglycerol lipase inhibitor). Inflammation and ischemia were simulated with TNF-α and IFN-γ and oxygen deprivation. Permeability changes were measured by transepithelial electrical resistance. The role of the CB1 receptor was explored using CB1-knockdown (CB1Kd) intestinal epithelial cells. Endocannabinoid levels were measured using liquid chromatography-mass spectrometry. Cytokine secretion was measured using multiplex and ELISA. URB597 and JZL184 caused a concentration-dependent increase in permeability via CB1 (P permeability via CB1 (P permeability caused by inflammation and hypoxia (P permeability response to inflammation (P permeability and in inflammatory and hypoxic conditions.-Karwad, M. A., Couch, D. G., Theophilidou, E., Sarmad, S., Barrett, D. A., Larvin, M., Wright, K. L., Lund, J. N., O'Sullivan, S. E. The role of CB1 in intestinal permeability and inflammation. © FASEB.