Dissertations / Theses on the topic 'Leukocyte-endothelial'
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Williams, Marcie Renee. "Leukocyte and endothelial gene expression: response to endothelial stimulation and leukocyte transmigration." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33817.
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Leukocyte transmigration is a critical step of the inflammatory process. In this project I have examined leukocyte responses to transmigration and endothelial responses to both chemical and mechanical stimuli which are known to be involved in leukocyte transmigration. My work has identified ~2500 differentially expressed genes following endothelial exposure to interleukin-1 beta (IL1β). Interestingly, IL1β induces up-regulation of claudin-1 and pre-b-cell colony enhancing factor and down-regulation of claudin-5 and occludin, which are all involved in maintaining endothelial cell-cell junctions. Analysis of endothelial cell (EC) transcriptional changes following neutrophil transmigration found few differentially expressed genes in comparison to IL1β treated ECs; indicating that the effects of transmigration on ECs are minimal in comparison to the global transcriptional changes induced by IL1β.
Atherosclerosis, characterized by monocyte accumulation within the vessel lumen, is found in regions of flow reversal and low time averaged oscillatory shear stress. I have examined the effects of this type of shear stress on endothelial cell gene expression. My data indicates that most genes differentially expressed under these conditions are controlled by low average shear stress rather than flow reversal. These differentially expressed genes are involved in regulating the cell cycle and the immune response. My work shows that cell proliferation is increased following exposure to low steady shear stress or exposure to reversing oscillatory flow in comparison to high steady shear stress. Additionally monocyte adhesion is increased following exposure of ECs to reversing oscillatory flow.
My work has also examined the impact of transmigration on monocyte gene expression. I have identified genes which are differentially expressed in monocytes by exposure to EC secretions, monocyte/EC contact, and diapedesis. I have also shown that freshly isolated human monocytes have reduced apoptosis following transmigration. Surprisingly, I also found that monocytes had reduced expression of anti-microbial peptides following transmigration.
Overall my work identifies important endothelial and leukocyte transcriptional responses to the process of transmigration which extends from cytokine stimulation through diapedesis.
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Jenkins, Yvonne. "Leukocyte - endothelial interactions in allograft rejection." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430338.
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Toothill, Valerie. "Leukocyte-endothelial cell interactions in inflammatory disease." Thesis, Open University, 1992. http://oro.open.ac.uk/57401/.
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For established manufacturing nations, increased competitive pressure has been the way of life since the late 1970s. For the most part however, production decision making in manufacturing industry has not changed to meet these new challenges. It usually takes a subordinate strategic role to the marketing and finance functions with the consequence that it accepts a reactive role in the corporate debate. The outcome is that strategic initiatives and developments are predominantly based on corporate marketing-decisions at the "front end" with manufacturing being forced to react at the "back end" of the debate. Since manufacturing managers come late into these discussions, it is difficult for them to successfully influence corporate decisions. All too often, the result is the formulation and later development of strategies which manufacturing is unable to successfully support. That is not to say that this happens for want of trying - strong is the work ethic in the manufacturing culture. However, if the basic link between the manufacturing processes and infrastructure (ie manufacturing strategy) and the market is not strategically sound, then the business will suffer. There are many reasons why manufacturing is typically reactive in the strategic debate. One important factor is the lack of appropriate concepts and language with which to explain or contribute to corporate decisions. This research has been undertaken to help redress this deficiency. The work began in the early 1980s. Upto that time, both the professional and academic contributions to the field of manufacturing strategy principally concerned statements which highlighted the problem and alerted manufacturing industry as a whole to its size and potential. However, there were in addition some important early pointers as to ways of overcoming the inadequacy of production's contribution to strategy formulation as well as some alternative approaches which firms needed to consider as ways of improving their overall performance. The inability of the production executive to contribute appropriate functional inputs provided the stimulus to undertake this work and to endeavour to build on initial insights as a way of taking forward the subject area of manufacturing strategy. The core of this thesis concerns these developments. Reported here are three contributions to this field of study all of which have been tested in different firms and are increasingly being used by academics, consultants and businesses as a way of helping to gain essential insights into what is a complex problem. The three facets are: • Typically, corporate strategies are composites of functional statements which are inadequately debated one with another in order to understand and test the coherence of the approaches proposed. The result is that the opportunity to fashion corporate strategies supported by all the functions within a business is not adequately pursued. In addition, the necessity to develop corporate strategy in this way and the advantages which ensue have gone unrecognised • The reactive role of manufacturing results in a lack of strategic direction within this function. As a result, typical developments and investments tend to take the form of operational responses undertaken without strategic context. One outcome of the research is a methodology which provides a way in which a business can develop a manufacturing strategy which links manufacturing developments and investments to the needs of its agreed markets. Two applications of this are provided in Chapter 4 • It is most important for an industrial company to recognise that it is attempting to support the inherently changing nature of its markets with manufacturing investments the characteristics of which are fixed in nature and will not change without further investments and developments. Product profiling is a methodology for enabling companies to assess the current level of match between its markets and manufacturing and to recognise the extent to which decisions will effect this in the future. Examples of its application illustrating different sources of mismatch are given in Chapter 5.
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Hart, Stephanie Hall Burridge Keith W. T. "Vascular endothelial cadherin phosphorylation modulates endothelial cell permeability and leukocyte transendothelial migration." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,2069.
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Thesis (M.S.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Feb. 17, 2009). "... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Pharmacology." Discipline: Pharmacology; Department/School: Medicine.
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Gautam, Narinder. "Mechanisms for leukocyte-mediated adjustment of endothelial barrier function /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4794-5/.
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Grooby, Warwick L. "Studies of endothelial and leukocyte cell adhesion molecules in renal transplantation /." Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phg876.pdf.
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Gao, Dingcheng. "On the pathophysiological significance of CD154-CD40 mediated leukocyte endothelial cell interaction." Doctoral thesis, [S.l.] : [s.n.], 2003. http://webdoc.sub.gwdg.de/diss/2003/gao/gao.pdf.
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Ehrnfelt, Cecilia. "In vitro models of xenograft rejection : studies on leukocyte-endothelial cell interactions /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7349-807-6/.
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Buckley, Christopher Dominic. "Molecular analysis of IgSF-integrin interactions : their role in leukocyte endothelial adhesion." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320117.
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Ismail, Hodan. "Vascular endothelial growth factor and angiopoietin-1 regulate leukocyte adhesion to endothelial cells through the nuclear receptor Nur77." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107844.
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Vascular endothelial growth factor (VEGF) and angiopoietin 1 (Ang-1) are critical regulators of angiogenesis. Additionally, both have been found to participate in inflammatory processes: VEGF as a pro-inflammatory and Ang-1 as an anti-inflammatory mediator. Nur77 is a member of a family of orphan receptors (NR4A) that includes Nurr1 and Nor1 and plays a role in regulating vascular inflammation; however, this has yet to be fully understood. The aim of this study was to evaluate whether Nur77 expression in endothelial cells (ECs) serves as a negative feedback mechanism designed to inhibit NFkappaB induction, dampen VEGF-induced E-selectin and VCAM1 expression and enhanced leukocyte adhesion to ECs, and mediate the suppression of EC activation induced by Ang-1 treatment.Treatment of human umbilical vein endothelial cells (HUVECs) with either VEGF or Ang-1 significantly and transiently induced Nur77 expression and enhanced PKD-dependent HDAC7 phosphorylation and mobilization from the nucleus to the cytosol. HUVECs transduced with adenoviruses expressing mutated HDAC7 or a dominant-negative PKD1 inhibited VEGF-, but not Ang-1-, induced Nur77 expression. Inhibition of PI3K and ERK1/2 resulted in the suppression of Ang-1-induced Nur77 expression whereas the inhibition of JNK resulted in significantly greater induction of Nur77 by Ang-1. NFκB binding activity and gel shift assays revealed that Nur77 inhibits VEGF-induced NFκB activity. Overexpression of Nur77 showed titre-dependent upregulation of IκBα mRNA and protein expressions that was not evident in HUVECs transduced with viruses expressing a dominant-negative form of Nur77 (Ad-dnNur77). Functionally, Nur77 was found to suppress VEGF-induced mRNA and protein expressions of the adhesion molecules E-selectin and VCAM1. Importantly, the role of Nur77 in cytokine-induced leukocyte adhesion to ECs was examined. Adherence of U937 cells to HUVECs activated by VEGF was suppressed by overexpressing Nur77 whereas the loss of Nur77 by siRNA interference resulted in augmentation of adhesion. Interestingly, Ang1 was able to dampen VEGF-induced monocyte adhesion to HUVEC monolayers. I conclude that Nur77 plays an important role in providing a negative feedback mechanism designed to attenuate VEGF-induced pro-inflammatory responses through selective inhibition of NFκB activation. Furthermore, Nur77, in part, may be vital to the Ang-1 anti-inflammatory response.Les facteurs de croissance endothélials vasculaires (VEGF) et l'angiopoïétine 1 (Ang-1) sont de régulateurs essentiels de l'angiogénèse. En outre, tous les deux ont été découverts pour leur participation dans le processus d'inflammation: VEGF comme pro-infammatoire et Ang-1 comme médiateur anti-inflammatoire. Nur77 est un membre de la famille des récepteurs orphelins (NR4A) qui comprend Nurr1 and Nor1 et jouent un rôle dans la régulation de l'inflammation vasculaire; toutefois cela n'est pas encore totalement compris. Le but de cette étude était d'évaluer si l'expression de Nur77 dans les cellules endothéliales (ECs) sert de mécanisme de rétroaction négatif conçu pour inhiber l'induction de NFκB en réduisant l'expression de la E-selectin et de VCAM1 induite par VEGF, ainsi que l'adhésion des leucocytes aux ECs, et pour agir en médiateur de la suppression de l'activation des ECs induite par le traitement avec Ang-1. Le traitement des cellules endothéliales humaines de la veine ombilicale (HUVECs) soit avec VEGF ou Ang-1 induit de façon significative et transitoire l'expression de Nur77 et augmente la Phosphorylation de HDAC7 PKD dépendante et la mobilisation du noyau vers le cytosol. Les HUVECs transduits avec les adénovirus exprimant HDAC7 muté ou un dominant négatif PKD1 inhibent VEGF, mais pas l'expression de Nur77 induit par Ang-1. L'inhibition de la PI3K et de ERK1/2 aboutit à la suppression de l'expression de Nur77 induit par Ang-1 alors que l'inhibition de JNK résulte de façon significative en une plus grande induction de Nur77 par Ang-1. L'essai d'activité de liaison de NFκB ainsi que celui du gel de retardation révèlent que Nur77 inhibe l'activité de NFκB induit par VEGF. La surexpression de Nur77 a montré une sur-régulation dépendante de la titration de l'ARNm et de l'expression protéique de IκBα, pas évidente avec les HUVECs transduites avec les virus exprimant la forme dominante négative de Nur77 (Ad-dnNur77). J'ai trouvé que Nur77 réprimait l'ARNm et l'expression protéique de E-selectin and VCAM1 induit par VEGF. De façon importante, le rôle de Nur77 dans l'adhésion des leucocytes aux ECs induits par les cytokines a été examiné. L'adhérence des cellules U937 aux HUVECs activées par VEGF était réprimée par la surexpression de Nur77 alors que la perte de Nur77 par l'ARNsi d'interférence résulte dans une augmentation de l'adhésion. De manière intéressante, Ang-1 était capable d'amortir l'adhésion aux monocouches de HUVECs induite par VEGF. Je conclus que Nur77 joue un rôle important en fournissant un mécanisme de rétroaction négatif conçu pour atténuer la réponse pro-infammatoire induite par VEGF à travers l'inhibition sélective de l'activation de NFκB. Par ailleurs Nur77 en partie, peut être vital pour les réponses anti-inflammatoires d'Ang-1.
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Quarmby, Steven Lee. "An investigation into the mechanisms responsible for leukocyte-endothelial cell interactions following irradiation." Thesis, Manchester Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388840.
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Singh, Manindra. "Characterization of Adipokine-Induced Responses for Inflammation and Leukocyte Interaction in Endothelial Cells." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou150169740307715.
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Musashi, Kunihoro. "Thrombin inhibitor reduces leukocyte-endothelial cell interactions and vascular leakage after scatter laser photocoagulation." Kyoto University, 2007. http://hdl.handle.net/2433/135742.
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Gillespie, Scarlett. "The effect of sulforaphane on leukocyte-endothelial interactions and platelet activation during inflammation and thrombosis." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/43852.
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Inflammation is thought to play a driving role in an expanding number of vascular and cerebral pathologies. Sulforaphane (SFN) is a naturally occurring isothiocyanate which has previously been shown to harbour anti-inflammatory properties in several immune cell types. In this work, intra vital microscopy was used to visualise the cellular interactions within the cerebral microvasculature stimulated downstream of an inflammatory challenge, namely intraperitoneal injection of LPS (0.1-4mg/kg). This resulted in a time, not dose, dependent stimulation of leukocyte-endothelial interactions; the number of rolling cells significantly increased, cells exhibited a slow rolling velocity and the number of adherent cells significantly increased versus sham or vehicle treated animals. SFN pre-treatment at 50mg/kg 24hr prior to LPS challenge (0.5mg/kg), increased the number of cells rolling through the cerebral microvasculature, significantly increased the speed at which they were rolling versus LPS treated animals and decreased the number of cells that were adherent to the pial vessel walls. These alterations were not associated with alterations in systemic cytokine levels (IL12p70, IL-6, TNFα, IL-10, IFNγ, MCP-1) or nuclear Nrf2 expression within the cerebral cortex. LPS (1µg/ml) increased IL-1β release from isolated human neutrophils which also showed no alteration following SFN incubation (0.1-25µM). Investigation into the effects of SFN revealed that SFN significantly altered the ability of platelets to aggregation in response to several agonists (thrombin, collagen and ADP), and that this response was not associated with the intracellular Ca2+ movement or induction of LDH release. This work highlights the ability of SFN to alter inflammatory cell interactions within the cerebral microvasculature in vivo, and also indicates the inhibitory effect of SFN on isolated platelet function ex vivo.
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Iwama, Daisuke. "Neuroprotective effect of cilostazol against retinal ischemic damage via inhibition of leukocyte-endothelial cell interactions." Kyoto University, 2009. http://hdl.handle.net/2433/124267.
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Huang, Hua. "Endothelial activation and inflammation in the tumor microenvironment." Doctoral thesis, Uppsala universitet, Institutionen för immunologi, genetik och patologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-247889.
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Tumors are composed not only of malignant cells, but also of various types of normal cells, including vascular cells and infiltrating immune cells, which drive tumor development and progression. The tumor vasculature is abnormal and dysfunctional due to sustained tumor angiogenesis driven by high levels of pro-angiogenic factors. Proteins differentially expressed in tumor vessels affect vascular function and the tumor microenvironment and may serve as targets for therapy. The tumor is also a site of sustained chronic inflammation. The recruitment and activation of inflammatory cells significantly influence tumor progression and regression. Targeting molecules regulating tumor angiogenesis and inflammation in the tumor microenvironment is therefore a promising strategy for the treatment of cancer. This thesis is aiming to understand and investigate the molecular regulation of these two processes in tumors. αB-crystallin is a heat shock protein previously proposed as a target for cancer therapy due to its role in increasing survival of tumor cells and enhancing tumor angiogenesis. In this thesis, we demonstrate a novel role of αB-crystallin in limiting expansion of CD11b+Gr1+ immature myeloid cells in pathological conditions, including tumor development. In addition, we show that αB-crystallin regulates leukocyte recruitment by promoting expression of adhesion molecules ICAM-1, VCAM-1 and E-selectin during TNF-α-induced endothelial activation. Therefore, targeting of αB-crystallin may influence tumor inflammation by regulating immature myeloid cell expansion and leukocyte recruitment. Abnormal, dysfunctional vessels are characteristic of glioblastomas, which are aggressive malignant brain tumors. We have identified the orphan G-protein coupled receptor ELTD1 as highly expressed in glioblastoma vessel and investigated its role in tumor angiogenesis. Interestingly, deficiency of ELTD1 was associated with increased growth of orthotopic GL261 glioma and T241 fibrosarcoma, but did not affect vessel density in any model. Further investigation is warranted to evaluate whether ELTD1 serves a suitable vascular target for glioblastoma treatment. Anti-angiogenic drugs targeting VEGF signaling is widely used in the clinic for various types of cancer. However, the influences of anti-angiogenic treatment on tumor inflammation have not been thoroughly investigated. We demonstrate that VEGF inhibits TNF-α-induced endothelial activation by repressing NF-κB activation and expression of chemokines involved in T-cell recruitment. Sunitinib, a small molecule kinase inhibitor targeting VEGF/VEGFR2 signaling increased expression of chemokines CXCL10, CXCL11, and enhanced T-lymphocyte infiltration into tumors. Our study suggests that anti-angiogenic therapy may improve immunotherapy by enhancing endothelial activation and facilitating immune cell infiltration into tumors.
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Hara, Tomijiro. "Cell surface thioredoxin-1 : possible involvement in thiol-mediated leukocyte-endothelial cell interaction through lipid rafts." Kyoto University, 2007. http://hdl.handle.net/2433/135769.
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Williamson, James Denis. "The role of endothelial adhesins in leukocyte adhesion in response to pharmaceutical agents that induce pulmonary fibrosis." Thesis, University of Hull, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682737.
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Bleomycin (BLM) is an antineoplastic agent known to cause pulmonary fibrosis as a side-effect, and is often used to model fibrotic disease in rodents. Although human BLM-induced pulmonary fibrosis (BPF) results from intravenous BLM delivery, rodent modelling today primarily uses the intratracheal delivery method. However, BPF following both dosing routes is characterised by inflammatory cell influx into the lung. Though it is thought that intratracheal dosing causes intrapulmonary injury, cytokine release, and resultant immune cell recruitment, the mechanism by which intravenous dosing causes immune cell influx is less clear. Endothelial cells are critically involved in immune cell extravasation to the site of injury, through adhesion molecule expression and cytokine release. This work assessed whether BLM induces endothelial adhesion molecule expression and cytokine release. It was found that the treatment of HUVECs and PMVECs with pharmacologically-relevant concentrations of BLM resulted in increased ICAM-1, VCAM-1, and (in HUVECs) E-selectin expression, and increased MCP-1 and IL-8 release. Endothelin-1 release was decreased by treatment. These alterations were regulated at a mRNA transcriptional level. Endothelial cell treatment with BLM also supported increased neutrophil tethering and adhesion to endothelial monolayers, although this appeared unrelated to increased ICAM-1 or E-selectin expression. This work reports the novel finding that pharmacologically-relevant concentrations of BLM increase adhesion molecule expression in both HUVECs and PMVECs, and compares the expression of adhesion molecules and cytokines in these cell types in response to BLM. This thesis also reports the unique discovery that BLM treatment increases leukocyte adhesion to endothelial monolayers under flow in vitro. Finally, the finding that endothelial adhesion molecule expression and cytokine release is increased in response to treatment with etoposide, another agent which causes lung fibrosis, is presented. This work suggests a potential mechanism which may contribute to the development of human BPF via immune cell recruitment to the lung. NB: The hard copy which contains a CD-ROM of videos is available for consultation in the Brynmor Jones Library.
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Rouleau, Léonie. "Endothelial cell response and leukocyte adhesion in an asymmetric stenosis model: role of fluid wall shear stress gradients." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86519.
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The focal nature of atherosclerosis has been associated with complex geometries. The response of endothelial cells to hemodynamics is believed to be linked to atherosclerotic plaque development, progression and rupture. Great advances have been made in our ability to study cellular responses to mechanical forces. Unfortunately, the inability to recreate in vitro the realistic in vivo mechanical stimuli may be obscuring our understanding. In order to determine the mechanistic link between hemodynamics and plaque stability, three dimensional in vitro cell culture models were designed and biomolecular techniques were adapted to analyze endothelial cell function. Dextran was used as a supplement to increase the growth medium viscosity and its effects were characterized. Straight/tubular in vitro models were used to study the acute and long term response of endothelial cells to wall shear stress (WSS) of different magnitude. Anatomically realistic and asymmetric stenosis models were created in order to examine the morphological response of endothelial cells to complex hemodynamic forces. Within the stenosis models, the regional adhesive properties of neutrophils were tested as well as the localized expression of inflammatory molecules. Results show that appropriate time matched dextran containing static controls are required as this additive modified inflammatory marker cell expression both under static and flow conditions in a concentration and time dependent manner. Endothelial cells exposed to wall shear stress altered their morphology depending on the magnitude and duration of exposure. Morphological adaptation was sensitive to the spatial wall shear stress gradients present in both the asymmetric stenosis and the anatomically realistic models. Neutrophil adhesion and inflammatory marker expression differed in the spatial WSS gradient regions of the asymmetric stenosis models. This study highlights the possible role for spatial wall shear stress gradients in tL'athérosclérose est une maladie qui se développe localement où le flux sanguin est perturbé. Les cellules endothéliales sont soumises en permanence à des contraintes mécaniques et leur réponse a été reliée au développement et à la progression de l'artériosclérose. Différentes chambres d'écoulement ont été développées in vitro afin d'étudier la réponse des cellules endothéliales aux forces de cisaillement et de grandes avancées ont été faites afin de mieux comprendre les réponses cellulaires à l'écoulement sanguin. Ces modèles ne peuvent reproduire adéquatement la complexité des conditions présentes in vivo. Ainsi, afin de déterminer le lien entre les forces hémodynamiques et la stabilité des plaques artérioscléreuses, des modèles tridimensionnels ont été développés ainsi que les techniques biomoléculaires nécessaire afin d'étudier la fonction des cellules à l'intérieur de ceux-ci. Du dextran a été utilisé comme supplément afin d'augmenter la viscosité du média de culture et son effet sur les cellules a été caractérisé. Des modèles tubulaires ont été utilisés afin d'étudier la réponse à court et à long terme des cellules endothéliales à des forces de cisaillement de diverses magnitudes. La réponse morphologique des cellules endothéliales, suite à l'exposition d'un débit constant, a été étudiée dans des modèles idéalisés de sténoses asymétriques et réalistes anatomiquement. L'expression régionale des cellules endothéliales et l'adhésion locale de neutrophiles dans les modèles sténosés ont été quantifiées en fonction de la durée et de la magnitude des forces de cisaillement. Les résultats obtenus démontrent que le dextran peut affecter la réponse des cellules et ainsi les contrôles appropriés doivent être utilisé. La morphologie des cellules endothéliales varie avec la durée et la force du cisaillement ainsi que dans les régions où des gradients sont présent
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Maccormac, Luci Penelope. "The effect of cytomegalovirus infection of endothelial cells on cell surface molecules involved in leukocyte adhesion, migration and immune recognition." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300625.
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Kadiyska, Ivelina [Verfasser], and Markus [Akademischer Betreuer] Hecker. "Implications of a genetically determined nitric oxide deficit for endothelial cell-leukocyte interaction and cardiovascular disease / Ivelina Kadiyska ; Betreuer: Markus Hecker." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/118061609X/34.
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Alharbi, Azzah Saeed E. "In vitro modelling of the formation of inflammatory platelet-leukocyte aggregates and their adhesion on endothelial cells (an early event in sepsis)." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42861.
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Sepsis, a severe systemic inflammatory response to an infection, is a global health problem with significant economic burden. Platelet leukocyte aggregates (PLAs) are extensively formed in sepsis, and correlate with severity of disease. Molecular interactions that lead to the formation and adherence of these cellular aggregates to endothelial cells might represent novel targets to use for therapy. Whole blood stimulation assays and flow cytometry are widely used to study the formation of PLA aggregates in an in vitro approach to understand the acute inflammatory reaction in the bloodstream to the presence of pathogen associated molecular patterns (PAMPs, most commonly LPS) during septicaemia. However, these assays are limited by the lack of robust and physiologically relevant conditions. Most importantly, the extent of spontaneous aggregate formation is unclear in most assays, as cells outside the body may aggregate, forming PLA. The aim of this work was to assess extent of spontaneous aggregate formation in whole blood stimulation assays and to compare the effects of endotoxin and of heat killed, clinically relevant, pathogens on aggregate formation and adhesion of complex aggregates to TNFα stimulated endothelial cells. Endotoxin from E.coli or Salmonella enteritidis was not a suitable stimulus to provoke sepsis relevant platelet leukocyte aggregates in vitro, as it did not further increase the extent of aggregates formed spontaneously in stasis of hirudin anticoagulated blood. By contrast, heat killed Klebsiella pneumoniae or Staphylococcus aureus produced significantly enhanced and complex cellular aggregates which adhered to TNFα stimulated endothelial cells. These were reliably captured by scanning electron microscopy. Adhesion of cellular aggregates could be blocked by incubation of endothelial cells with a commercial P-Selectin antibody and a novel angiopoietin-2 ligand trap. In conclusion, a method was developed that models the acute inflammatory reaction in whole blood in the presence of relevant pathogen surfaces.
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Gandhi, Neha Sureshchandra. "Molecular modelling of platelet endothelial cell adhesion molecule 1 and its interaction with glycosaminoglycans." Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/1513.
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The Platelet Endothelial Cell Adhesion Molecule 1 (PECAM-1) has many functions including its roles in leukocyte extravasation as part of the inflammatory response, and in the maintenance of vascular integrity through its contribution to endothelial cell-cell adhesion. Various heterophilic ligands of PECAM-1 have been proposed. The possible interaction of PECAM-1 with glycosaminoglycans (GAGs) is the focus of this thesis. The three dimensional structure of the extracellular immunoglobulin (Ig)-domains of PECAM-1 was constructed using homology modelling and threading methods. Potential heparin/heparan sulfate binding sites were predicted on the basis of their amino acid consensus sequences and a comparison with known structures of sulfate binding proteins. Heparin and other GAG fragments have been docked to investigate the structural determinants of their protein binding specificity and selectivity. It is predicted that two regions in PECAM-1 appear to bind heparin oligosaccharides. A high affinity binding region was located in Ig-domains 2 and 3 and a low affinity region was located in Ig-domains 5 and 6.These GAG binding regions are distinct from regions involved in PECAM-1 homophilic interactions. Docking of heparin fragments of different size revealed that fragments as small as a pentasaccharide appear to be able to bind to domains 2 and 3 with high affinity. Binding of longer heparin fragments suggests that key interactions can occur between six sulfates in a hexasaccharide with no further increase in binding affinity for longer fragments. Molecular dynamics simulations were also used to characterise and quantify the interactions of heparin fragments with PECAM-1. These simulations confirmed the existence of regions of high and low affinity for GAG binding and revealed that both electrostatic and van der Waals interactions determine the specificity and binding affinity of GAG fragments to PECAM-1. The simulations also suggested the existence of ‘open’ and ‘closed’ conformations of PECAM-1 around domains 2 and 3.
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Rodrigues, Stephen Fernandes de Paula. "Interação anlodipina/diclofenaco sobre o comportamento leucocitário em ratos espontaneamente hipertensos (SHR) e ratos wistar normotensos." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/42/42136/tde-10092008-122935/.
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Anlodipina e diclofenaco podem ser combinados de forma que o potencial de interação é alto. Investigamos se anlodipina interfere com o efeito antimigratório do diclofenaco em ratos espontaneamente hipertensos (SHR) e ratos wistar. Os ratos foram tratados (15 dias) com diclofenaco e anlodipina, juntos ou separadamente. A migração leucocitária foi estudada por microscopia intravital e a expressão de moléculas de aderência por imunohistoquímica. A anlodipina reduziu migração leucocitária em SHR e ratos wistar por reduzir a expressão de ICAM-1 em células endoteliais venulares. A redução da migração leucocitária em ratos wistar pode decorrer também da redução da expressão de PECAM-1 em células endoteliais. A combinação reduziu o efeito do diclofenaco sobre a migração em SHR e wistar. Em SHR esse efeito envolveu a redução de ICAM-1. A redução da PA causada pela anlodipina em SHR parece contribuir para a redução da migração leucocitária. Interação farmacocinética foi excluída.Amlodipine and diclofenac may be combined so the potential for interaction of both is high. We determined if amlodipine interferes with the antimigratory effect of diclofenac in spontaneously hypertensive rats (SHR) and wistar rats. Rats were treated with either diclofenac or amlodipine alone or combined (for 15 days). Leukocyte migration was evaluated by intravital microscopy and cell adherence molecules expression by immunohistochemistry. Amlodipine reduces migration in both SHR and wistar rats by reducing venular endothelial cell ICAM-1 expression. In wistar the antimigratory effect of amlodipine may also be due to reduction in PECAM-1 expression. Diclofenac effect was reduced by amlodipine in both SHR and wistar. In SHR amlodipine reduces the effect of diclofenac by impairing its reducing effect on ICAM-1. Reduction of the BP levels seems to contribute to reduction of the leukocyte migration caused by amlodipine in SHR. Pharmacokinetic interaction was excluded.
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Krga, Irena. "Role des anthocyanes et des métabolites sur la fonction des cellules endothéliales et plaquettes humaine in vitro." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAS004/document.
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Un nombre croissant de preuves suggèrent le rôle bénéfique des anthocyanes alimentaires, composés phyto-chimiques principalement présents dans les baies et les produits dérivés, sur la santé cardiovasculaire. Ces bénéfices peuvent être attribués à leur effet sur les cellules endothéliales ou les plaquettes qui sont les acteurs clés dans le développement des maladies cardiovasculaires (MCV). Cependant, les mécanismes moléculaires sous-jacents aux effets cardio-protecteurs de l'anthocyanine ne sont pas entièrement compris. L'objectif de cette thèse était d'évaluer l'effet in vitro des anthocyanines et de leurs métabolites, dans des conditions physiologiques, sur la fonction endothéliale et plaquettaire et d'identifier les mécanismes sous-jacents à leur action. Les résultats de ma thèse ont montré que le prétraitement des cellules endothéliales avec des concentrations physiologiques d'anthocyanes et de leurs métabolites circulants diminue l'adhésion des monocytes aux cellules endothéliales activées ainsi que leur migration transendothéliale qui sont les étapes initiales du développement de l'athérosclérose précédant le MCV. En accord avec ces résultats, l'analyse de l'expression génique a révélé que le traitement des cellules endothéliales avec ces molécules modulait l'expression des gènes impliqués dans la régulation de l'adhésion cellulaire, le réarrangement du cytosquelette d'actine, l'adhésion focale et la transmigration leucocytaire. Les analyses bioinformatiques de ces données ont permis d'identifier les facteurs de transcription potentiellement impliqués dans les effets nutrigénomiques observés ainsi que les protéines de signalisation cellulaire régulant leur activité. Les analyses bioinformatiques ont permit d’identifier des protéines de signalisation cellulaire auxquelles ces bioactifs peuvent se lier et potentiellement affecter leur activité entraînant modification d’activité des protéines de signalisation en aval. L’impact sur des facteurs de transcription a également été cherché et ces effets ont été confirmés par les résultats obtenus des analyses par Western blot. Les anthocyanines et leurs métabolites ont également modulé l'expression de microARN, en particulier ceux impliqués dans la régulation de la perméabilité des cellules endothéliales, contribuant ainsi aux changements observés dans la fonction endothéliale. En plus de leurs effets sur les cellules endothéliales, les résultats de mes travaux ont également montré la capacité des anthocyanes et de leurs métabolites à moduler la fonction plaquettaire en diminuant l'activation plaquettaire et leur agrégation avec les leucocytes, qui contribuent fortement au développement des MCV.En conclusion, les résultats de ma thèse ont révélé les effets positifs des anthocyanes et de leurs métabolites, aux concentrations physiologiques, sur la fonction endothéliale et plaquettaire et ont fourni de nouvelles informations sur les mécanismes sous-jacents de leurs effets cardio-protecteursIncreasing number of scientific evidence suggests the beneficial role of dietary anthocyanins, phytochemicals mainly present in berries and derived products, in cardiovascular health. These anthocyanin health benefits may be attributed to their effect on endothelial cells or platelets that represent the key players in the development of cardiovascular diseases (CVD). However, the exact molecular mechanisms underlying anthocyanin cardioprotective effects are not fully understood. The aim of this thesis was to investigate the effect of anthocyanins and their metabolites in vitro on endothelial and platelet function and identify the underlying mechanisms of their action using physiologically relevant conditions.Results from this thesis showed that the pretreatment of endothelial cells with physiologically relevant concentrations of circulating anthocyanins and their metabolites attenuated monocyte adhesion to activated endothelial cells as well as their transendothelial migration, which are the initial steps in the development of atherosclerosis that precede CVD. In agreement with these results, gene expression analysis revealed that the treatment of endothelial cells with these compounds modulated the expression of genes involved in regulation of cell-cell adhesion, actin cytoskeleton reorganisation, focal adhesion and leukocyte transmigration. Bioinformatics analyses of gene expression data allowed the identification of potential transcription factors involved in the observed nutrigenomic effects and cell signalling proteins regulating their activity.Molecular docking analyses further revealed cell signalling proteins to which these bioactives may bind to and potentially affect their activity and the activation of downstream signalling proteins and transcription factors, effects that were in agreement with the results of Western blot analyses. Anthocyanins and their metabolites also modulated the expression of microRNAs, especially those involved in regulation of endothelial cell permeability, contributing to the observed changes in endothelial cell function.In addition to their effects on endothelial cells, anthocyanins and their metabolites displayed the capacity to modulate platelet function by decreasing platelet activation and their aggregation with leukocytes, the processes that are important contributors to CVD development.In conclusion, results from this thesis revealed the positive effects of anthocyanins and their metabolites, at physiologically relevant concentrations, on endothelial and platelet function and provided new insights into the mechanisms underlying their cardioprotective effects
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Altamimy, Raed Adill Hannon. "Interactions between coronary artery endothelial cells and leukocyte MPs shed in response to E. coli lipopolysaccharide : in-vitro and ex-vivo studies of the impact of vascular ageing and of high glucose." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ024/document.
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Les microparticules (MP) sont des vésicules de la membrane plasmique émises après stress cellulaire. Nous avons étudié le rôle des MPs leucocytaires extraites de la rate de rats comme marqueur du vieillissement et effecteurs de la senescence et de la dysfonction endothéliales induites par les fortes concentrations de glucose (HG). L’émission basale de MP augmente avec l’âge qui favorise leur génération en réponse au LPS ou au PMA/ionophore A23187 (MPLPS, MPPMA/I). Les MP de rats âgés mais pas de jeunes induisent la sénescence de cellules endothéliales primaires d’artères coronaires (AC) de porc. MPLPS ou MPPMA/I de rats jeunes, mais pas MPCTL (cellules non traitées) réduisent la relaxation dépendante de l’endothélium d’anneaux d’AC en réponse à la bradykinine avec sous-expression de eNOS, surexpression de COX2, ICAM-1, VCAM-1. HG favorise l’émission des MP de rate. Dans les AC en HG, la vasoconstriction en réponse au U46619l est diminuée de manière dépendante du SGLT1/2 et de l’EDHFMicroparticles (MP) are plasma membrane vesicles shed from stimulated cells. We investigated whether leukocyte MP extracted from rat spleen are reliable markers of aging and effectors of high glucose (HG)-induced endothelial senescence and dysfunction. Data indicate that ageing enhances MP shedding from spleen cells of middle-age and aged rats and raises MP release in response to LPS, or to PMA and ionophore A23187. Of note, MP from aged but not young rats induced senescence of porcine coronary artery primary endothelial cells. In young rats, MPLPS, MPPMA/I but not from resting cells (MPCTL) reduced the endothelial-dependent relaxation of coronary artery rings (CAR) in response to bradykinin with down-regulation of eNOS, up-regulation of COX-2, ICAM-1, VCAM-1. HG enhanced early and late MP release from spleen cells. Prolonged exposure to HG potentiated endothelial dysfunction in CAR and altered vasoconstriction in response to U46619l in a SGLT1/2 and EDHF dependent manner
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Zanoni, Fernando Luiz. "Estudo dos efeitos da solução salina hipertônica e do Ringer lactato sobre a resposta da microcirculação mesentérica e a translocação bacteriana em modelo de obstrução intestinal e isquemia em ratos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/5/5152/tde-27092010-152952/.
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INTRODUÇÃO: Estudos demonstram que a solução salina hipertônica melhora a hemodinâmica, a microcirculação e modula o sistema imune, atenuando a resposta inflamatória associada ao choque e trauma. Este estudo tem por objetivo avaliar e comparar os efeitos da solução salina hipertônica (NaCl, 7,5%) e do Ringer lactato seguido da ressecção de segmento do intestino necrosado no tratamento da obstrução intestinal e isquemia, através da análise da translocação bacteriana, da disfunção microcirculatória mesentérica, dos distúrbios hemodinâmicos e metabólicos e da disfunção orgânica. MÉTODOS: Ratos Wistar machos (250 300 g) anestesiados (pentobarbital sódico, 50 mg/kg, i.p.) foram submetidos à obstrução intestinal e isquemia (OI, ligadura ao nível do íleo terminal seguida de ligadura de ramos da artéria mesentérica correspondentes à irrigação de 7 10 cm do íleo). Duas horas após os animais foram randomizados em: OI sem tratamento (OI); OI tratado com Ringer lactato (RL, 4 mL/kg, i.v.); e OI tratado com solução salina hipertônica (SH 7,5%, 4 mL/kg, i.v.). Vinte e quatro horas após os procedimentos cirúrgicos iniciais, os ratos obstruídos (OI, RL e SH) foram submetidos à enterectomia. Ratos controles falso-operados (FO) foram submetidos à lapatotomia. Os seguintes parâmetros foram analisados: 1) cultura bacteriana (E. coli) em amostras de linfonodos mesentéricos, fígado, baço e sangue; 2) análise das interações leucócito-endotélio na microcirculação mesentérica por técnica de microscopia intravital; 3) expressão de moléculas de adesão endoteliais (P-selectina e ICAM-1) por imunohistoquímica; 4) quantificação das citocinas e quimiocinas CINC-1 e CINC-2 no soro por enzimaimunoensaio; 5) histologia intestinal; 6) bioquímica sérica; 7) gasometria, hematócrito, lactato, glicose e leucograma; 8) insulina e corticosterona e; 9) sobrevida. RESULTADOS: O tratamento com SH reduziu a bacteremia, a incidência de animais com amostras positivas para E. coli (57%) e a quantidade de colônias bacterianas (p<0,05) comparado ao tratamento com RL ou aos animais não tratados (OI). As interações leucócito-endotélio e a expressão das moléculas de adesão, P-selectina e ICAM-1, reduziram-se após tratamento com SH seguido de enterectomia a valores observados no grupo controle FO (p>0,05). Ambos os tratamentos, SH e RL, associados à enterectomia normalizaram as concentrações séricas de CINC-1 e CINC-2 (p>0,05). Alterações de PaCO2, pH, lactato e glicemia normalizaram-se após o tratamento dos animais com SH ou RL seguido de enterectomia. A hipoinsulinemia registrada nos ratos OI foi prevenida pelo tratamento dos animais com SH ou RL. As concentrações séricas de corticosterona normalizaram-se após tratamento dos animais com SH associado à enterectomia. A magnitude da lesão intestinal, evidenciada por dano da membrana basal, edema, congestão e presença de células inflamatórias, foi menor no grupo tratado com SH comparado ao tratamento com RL, ambos associados à enterectomia. As concentrações de uréia, creatinina e a atividade das enzimas hepáticas normalizaram-se após tratamento com SH e enterectomia. Houve um aumento significativo da sobrevida dos animais (86%, 15 dias) e no ganho de peso corpóreo (p>0,05 vs FO) no grupo tratado com SH seguido de enterectomia. CONCLUSÕES: A estabilização de ratos submetidos à OI com SH associada à enterectomia resultou em aumento significativo da sobrevida dos animais. A SH reduziu a resposta inflamatória local (interações leucócito-endotélio e expressão de moléculas de adesão na microcirculação mesentérica, e lesão intestinal) e sistêmica (concentrações séricas de CINC-1 e CINC-2, disfunção renal e hepática)BACKGROUND: It has been shown that hypertonic saline solution improve hemodynamics, the microcirculation, and modulate the immune system, attenuating the inflammatory response associated with shock and trauma. The present study aims to investigate and compare the effects of hypertonic saline solution (NaCl, 7.5%) and lactated Ringer´s solution in the treatment of intestinal obstruction and ischemia, analysing the bacterial translocation phenomenon, mesenteric microcirculatory dysfunctions, hemodynamic/metabolic disturbances, and organ dysfunction in a rat model of intestinal obstruction and ischemia (IO) followed by resection of the necrotic small bowel segment. METHODS: Anesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250-300 g) were submitted to IO (ligature at the level of the terminal ileum, followed by ligation of mesenteric vessels that supply 7 10 cm of the ileal loop). Two hours thereafter animals were randomized into: IO without treatment; IO treated with lactated Ringer´s (LR, 4 ml/kg, i.v.) solution; IO treated with hypertonic saline (HS, 7.5%, 4 mL/kg, i.v.) solution. Twenty-four hours thereafter, IO rats (IO, LR, HS) were submitted to enterectomy. Control Sham-operated rats were submitted to laparotomy only. The following parameters were analysed: 1) bacterial cultures (E. coli) from mesenteric lymph nodes, liver, spleen, and blood samples; 2) analyses of leukocyte-endothelial interactions at the mesenteric microcirculation by intravital microscopy; 3) expression of endothelial adhesion molecules (P-selectin, ICAM-1) by immunohistochemistry; 4) quantification of serum cytokines and chemokines (CINC-1, CINC-2) by enzyme-linked immunosorbent assay; 5) intestinal histology; 6) serum biochemistry; 7) blood gases, hematocrit, lactate, glycemia, white blood cell counts; 8) serum insulin and corticosterone; 9) survival rate. RESULTS: Treatment with HS reduced the number of animals with positive samples for the presence of E. coli (57%) and the number of CFU/g tissue (p<0.05) compared to LR treated rats or IO rats without treatment. Leukocyteendothelial interactions and expression of the adhesion molecules, Pselectin and ICAM-1, were reduced after treatment with HS solution followed by enterectomy. Values attained matched those observed in Sham group (p>0.05). Both treatments, HS and LR associated with enterectomy, reduced serum levels of CINC-1 and CINC-2 to normal values (p>0.05 vs Sham). PaCO2, pH, lactate, and glucose were normalized after treatment of the animals with HS or LR followed by enterectomy. The hypoinsulinemia observed in the IO rats was prevented by treatment of the animals with HS or LR. Corticosterone concentrations were normalized after treatment of the animals with HS associated with enterectomy. The magnitude of the intestinal lesion, characterized by basal membrane injury, edema, congestion, and inflammatory cells, was smaller in the HS group compared to LR group, both treatments associated with enterectomy. Serum urea and creatinine levels, and the activity of hepatic enzymes were normalized after treatment with HS and enterectomy. A significant increase in survival rate (86%, 15 days) and in the body weight gain (p>0.05 vs Sham) were observed after treatment of the animals with HS and enterectomy. CONCLUSIONS: Treatment of the animals with HS solution followed by enterectomy significantly increased the survival rate. HS solution reduced the magnitude of the local inflammatory response (leukocyte-endothelial interactions, and adhesion molecules expression in the mesenteric microcirculation, and the intestinal lesion) and the systemic inflammatory response (CINC-1 and CINC-2 serum levels, renal and hepatic dysfunctions)
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Seidman, Michael Aaron. "An inconvenient truth : leukocyte transendothelial migration without pecam /." Access full-text from WCMC:, 2008. http://proquest.umi.com/pqdweb?did=1428864521&sid=12&Fmt=2&clientId=8424&RQT=309&VName=PQD.
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Nicholson, Martin William Michael. "Molecular analysis of the leukocyte cell-surface adhesion protein L-selectin." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260752.
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Correia, Cristiano de Jesus. "Estudo dos efeitos da solução salina hipertônica nas alterações microcirculatórias e no desenvolvimento do processo inflamatório em modelo de morte encefálica em ratos." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-09052018-102929/.
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INTRODUÇÂO: A morte encefálica (ME) induz instabilidade hemodinâmica com hipoperfusão microcirculatória, desencadeando inflamação e disfunção de órgãos. OBJETIVO: Este estudo teve como objetivo investigar os efeitos da solução salina hipertônica (SH) 7,5% na evolução da resposta inflamatória no tecido mesentérico de ratos submetidos à ME. MÉTODOS: Ratos Wistar machos foram anestesiados e ventilados mecanicamente. A ME foi induzida pela insuflação rápida de um balão posicionado na cavidade intracraniana (Fogart 4F). Os ratos foram divididos aleatoriamente em: 1) Falso-operado, ratos submetidos aos procedimentos cirúrgicos e trepanação (FO, n=17); 2) Controle, ratos tratados com solução salina isotônica (NaCl 0,9%, 4 mL/kg) imediatamente após ME (CO, n=17); 3) Solução hipertônica 1, ratos tratados com solução hipertônica (NaCl 7,5%, 4 mL/kg) imediatamente após ME (SH1, n=17); 4) Solução hipertônica 60, ratos tratados com solução hipertônica 60 min após ME (SH60, n=17). Três horas após a indução da ME ou o término do procedimento cirúrgico para os animais do grupo FO, foram coletados os seguintes dados: (a) perfusão mesentérica, fluxo sanguíneo e interações leucócito-endotélio no mesentério, pela técnica de microscopia intravital; (b) expressão de proteínas de óxido nítrico sintase endotelial (eNOS), endotelina-1, P-selectina e molécula de adesão intercelular (ICAM)-1, por imunohistoquímica; (c) expressão gênica de eNOS e endotelina-1, por reação em cadeia da polimerase em tempo real (PCR); (d) concentrações séricas de citocinas, quimiocinas e corticosterona por meio de enzimaimunoensaio (ELISA). RESULTADOS: Todos os grupos submetidos a ME apresentaram um comportamento semelhante da pressão arterial, sendo observado um pico hipertensivo, seguido de período de hipotensão, logo após a insuflação do cateter intra-craniano. A proporção de pequenos vasos perfundidos foi diminuída no grupo CO (46%) em comparação com FO (74%, p=0,0039). A SH foi capaz de restaurar a proporção de vasos perfundidos (SH1=71%, p=0,0018). Não houve diferenças no fluxo sanguíneo mesentérico entre os grupos. A expressão proteica de eNOS aumentou significativamente em ratos com SH (SH1 e SH60, p=0,0002) em comparação ao grupo CO. Resultados semelhantes foram observados em relação à endotelina-1 (p < 0,0001). Não houve diferenças na expressão gênica de eNOS e endotelina-1. O aumento no número de leucócitos \"rollers\" (p=0,0015) e migrados (p=0,0063) foi observado no grupo CO em comparação com FO. Ratos com SH demonstraram redução significativa em todos os parâmetros da interação leucócito-endotélio. Com relação às moléculas de adesão, a expressão de ICAM-1 estava elevada no grupo CO em comparação com o FO, enquanto que o tratamento com SH diminuiu a expressão de ICAM-1 (SH1 e SH60, p=0,0002). CONCLUSÕES: O emprego da solução salina hipertônica melhorou a perfusão mesentérica, influenciou positivamente o metabolismo do óxido nítrico e reduziu a inflamação no mesentério, com diminuição da adesão e migração leucocitária, em ratos submetidos a MEBACKGROUND: Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion leading to increased organ inflammation and dysfunction. OBJETIVE: To investigate the effects of 7.5% hypertonic saline solution (HS) on the course of the inflammatory response in rats submitted to BD. METHODS: Male Wistar rats were anesthetized and mechanically ventilated. BD was induced by rapid inflation of intracranial balloon catheter (Fogart 4F). Rats were randomly divided in: 1) Sham-operated, rats submitted only to trepanation (SH, n=17); 2) Control, rats treated with normal saline solution (NaCl 0.9%, 4 mL/kg) immediately after BD (CO, n=17); 3) Hypertonic solution 1, rats treated with hypertonic solution (NaCl 7.5%, 4 mL/kg) immediately after BD (HS1, n=17); 4) Hypertonic solution 60, rats treated with hypertonic solution 60 min after BD (HS60, n=17). Hundred eighty minutes thereafter the following experiments were performed: (a) mesenteric perfusion, blood flow, and leukocyte-endothelial interactions, by intravital microscopy; (b) protein expression of endothelial nitric oxide synthase (eNOS), endothelin-1, P-selectin, and intercellular cell adhesion molecule (ICAM)-1, by immunohistochemistry; (c) gene expression of eNOS, and endothelin-1, by real-time polymerase chain reaction (PCR); (d) serum concentrations of cytokines, chemokines and corticosterone by enzyme-linked immunosorbent assay (ELISA). RESULTS: All BD groups presented similar hypertensive peak followed by hypotension. The proportion of perfused small vessels was decreased in CO group (46%) compared to SH (74%, p=0.0039). HS was able to restore the proportion of perfused vessels (HS1=71%, p=0.0018). There were no differences in mesenteric blood flow between groups. eNOS protein expression significantly increased in rats given HS (HS1, and HS60, p=0.0002). Similar results were observed regarding endothelin-1 (p < 0.0001). There were no differences in eNOS and endothelin-1 gene expression. Increased numbers of rolling (p=0.0015) and migrated (p=0.0063) leukocytes were observed in CO group compared to SH. Rats given HS demonstrated an overall reduction in leukocyte-endothelial interactions. Levels of ICAM-1 increased in CO group compared to SH, and decreased in HS-treated groups (p=0.0002). CONCLUSIONS: Hypertonic saline improves mesenteric perfusion, increased eNOS and endothelin-1 protein expression, and reduced inflammation by decreasing leukocyte adhesion and migration in BD rats
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Su, Wen-Hong, and 蘇文弘. "Polymorphonuclear Leukocyte Transmigration-Induced Endothelial Responses." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/20055934120430558304.
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博士國立成功大學
基礎醫學研究所
91
Vascular endothelium plays an important role in regulating the transendothelial migration of polymorphonuclear leukocytes (PMNs). In this study, we examined at single-cell level the intracellular calcium ion ([Ca2+]i) signaling of endothelial cells (ECs) during PMN transmigration. Human umbilical vein ECs were cultured on a thin layer of collagen gel. The ECs were labeled with fura-2 AM, immersed in formyl-Met-Leu-Phe, and subsequently perfused with fresh buffer in order to establish a gradient of chemoattractant across the EC monolayer. The entire process of PMN rolling on, adhering to, and transmigrating across the EC monolayer was recorded under both phase-contrast and fluorescence optics. We found that 1) At high concentration (~3 x106/ml), both PMN suspension and its supernatant stimulated frequent EC [Ca2+]i elevations across the monolayer; 2) when used at lower concentration (~5 x 105/ml) to avoid the interference of soluble factors, PMN transmigration, but not rolling nor adhesion, was accompanied by EC [Ca2+]i elevation; 3) the latter EC [Ca2+]i elevation occurred simultaneously in ECs adjacent to the transmigration site, but not in those which were not in direct contact with the transmigrating PMN; 4) this EC [Ca2+]i elevations was an initial and required event for PMN transmigration; 5) BAPTA-pretreated PMNs transmigrated with accompanying EC [Ca2+]i elevation but they became much elongated in the collagen gel. In conclusion, PMNs induce adjacent EC [Ca2+]i signaling that apparently mediates the ‘gating’ step for their subsequent transmigration. Most existing evidence regarding junction protein movements during transendothelial migration of leukocytes comes from taking post-fixation snap shots of the transendothelial migration process that happens on a cultured endothelial monolayer. In this study, we used junction protein-specific antibodies that did not interfere the transendothelial migration to examine the real-time movements of vascular endothelial-cadherin (VE-cadherin) and platelet/endothelial cell adhesion molecule-1 (PECAM-1) during transmigration of polymorphonuclear leukocytes (PMNs) either through a cultured endothelial monolayer or through the endothelium of a dissected human umbilical vein tissue. Both junction proteins showed relative movements, not transient disappearance, at the PMN transmigration sites under either experimental model system. VE-cadherin moved away from the transmigration site to different ends of it, whereas PECAM-1 opened to surround the periphery of a transmigrating PMN. Junction proteins usually moved back to their original positions when the PMN transmigration process was completed in less than 2 min. The relative positions of some junction proteins might rearrange to form a new inter-endothelial contour when PMNs preferentially transmigrated through multi-cellular corners. Although transmigrated PMNs maintained good mobility, they only moved laterally underneath the vascular endothelium instead of deeply into the vascular tissue. In conclusion, our results obtained from using either cultured cells or vascular tissues showed that VE-cadherin-containing adherent junctions were relocated aside, not opened or disrupted, while PECAM-1-containing junctions were opened, during PMN transendothelial migration.
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Chia-ChiChen and 陳佳琪. "The Role of Leukocyte Thrombomodulin in Mediating Leukocyte-Endothelial Interaction upon Vascular Inflammation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/y34e93.
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碩士國立成功大學
生物化學暨分子生物學研究所
102
Thrombomodulin (TM), a widely expressed transmembrane glycoprotein, has multiple functional domains. In addition to the well-known anticoagulant function, TM also regulates inflammatory responses. However, the role of TM on leukocyte still remains unclear. Our data previously showed that TM can specifically bind to the carbohydrate, Lewis Y (Ley), via its N-terminal lectin-like domain. Ley is found to be glycosylated on adhesion molecules and involved in cell adhesion. In this study, we intended to investigate whether leukocyte surface TM would participate in leukocyte adhesion by interacting with Ley on endothelial cells under inflammation. We analyzed membrane TM expression on THP-1 monocytic cells under various stimuli. The expression of TM on THP-1 monocytic cells was upregulated by monocyte activating agent, phorbol 12-myristate 13-acetate, as well as by inflammatory factors, tumor necrosis factor alpha and lipopolysaccharides. By using enzyme-linked immunosorbent assay, we found that soluble Ley could directly bind to TM on the surface of THP-1 monocytic cells. Moreover, the adhesion of rolling THP-1 monocytic cells to Ley-immobilized flow chamber was TM dependent. We further found that Ley could trigger p38 phosphorylation and was also TM dependent, which in turn led to β2-integrin activation, in THP-1 monocytic cells. By using transwell assay, the interaction of Ley and TM contributed to transendothelial migration, and which was abrogated by antibodies against either TM or Ley. To determine whether leukocyte TM would participate in leukocyte recruitment in vivo, we performed carotid artery ligation to induce vascular inflammation in wild-type (TMf/f) and myeloid-specific TM-deficient (LysMCre/TMf/f) mice. Reduced leukocyte recruitment and neointima formation were observed in myeloid-specific TM-deficient mice following carotid artery ligation. Our data provide a new insight showing that leukocyte TM could mediate leukocyte-endothelial interaction via binding to endothelial cell surface Ley under inflammation.
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Jones, David Alan. "Leukocyte adhesion to endothelial cells under flow conditions." Thesis, 1994. http://hdl.handle.net/1911/16745.
Full textAbstract:
Leukocyte adhesion to the endothelial cells lining blood vessel walls is a central event in the body's response to injury or infection. These interactions take place in the flowing bloodstream, and previous work has shown that fluid flow effects greatly influence the function of the adhesion receptors involved. In these studies, we use a parallel-plate flow chamber and videomicroscopy to quantitate leukocyte adhesion under flow conditions in vitro. First, we report studies of neutrophil adhesion to histamine-stimulated human umbilical vein endothelial cells (HUVECs). Most neutrophils roll along the HUVECs under these conditions, and a few adhere firmly. The rolling is mediated by P-selectin while the firm adhesion is mediated by $\beta\sb2$ integrins binding to ICAM-1, and we quantitate these interactions to generate data useful in understanding selectin-mediated rolling and integrin-mediated firm adhesion. Next, we report studies of T lymphocyte adhesion to HUVECs stimulated for 24 hours with interleukin-l (IL-1). Firm adhesion of T cells in this system is mediated by both ICAM-1/$\alpha\sb{L}\beta\sb2$ integrin and VCAM-1/$\alpha\sb4\beta\sb1$ integrin interactions, and we find that initial adhesion and rolling are mediated by a third pathway which does not appear to involve any of the previously characterized adhesion molecules. To investigate the molecular constituents of this pathway, we use a monoclonal antibody approach based on the observation that HUVECs stimulated with both IL-1 and IL-4 do not support any adhesion of T cells under flow conditions even though expression of the known endothelial cell adhesion receptors is similar to expression on IL-1-stimulated HUVECs. This approach has not yet been successful, and we also report results of preliminary experiments related to possible alternative approaches.
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MARTINELLO, Marianna. "A role for leukocyte-endothelial adhesion mechanisms in epilepsy." Doctoral thesis, 2009. http://hdl.handle.net/11562/337459.
Full textAbstract:
Il presente progetto di ricerca per il Dottorato in Scienze Biomediche Traslazionali ha
avuto come obiettivo uno studio sperimentale delle implicazioni del reclutamento
leucocitario nella patogenesi e nella evoluzione dell’epilessia.
I meccanismi coinvolti nella patogenesi dell’epilessia, una patologia neurologica
cronica che colpisce circa l’uno percento della popolazione mondiale, non sono
ancora chiari1-3. Tuttavia studi recenti suggeriscono che l’infiammazione potrebbe
giocare un ruolo nella patogenesi di questa malattia. Il reclutamento leucocitario è una
caratteristica ed un punto di intervento terapeutico fondamentale nell’infiammazione
tissutale, ma un ruolo per le interazioni tra leucociti ed endotelio nella patogenesi
delle crisi epilettiche non è ancora stato esplorato.
Nel presente progetto abbiamo utilizzato un modello murino di epilessia, indotto da
pilocarpina, ed abbiamo dimostrato che le crisi inducono a livello dei vasi cerebrali
elevata espressione di molecole di adesione vascolari, come vascular cell adhesion
molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) e selectine.
Mediante la tecnica della microscopia intravitale sono state evidenziate aumentate
interazioni (rotolamento ed arresto) in vivo da parte di granulociti e leucociti TH1 con
l’endotelio cerebrale dopo le crisi, ed è stato osservato che queste interazioni sono
mediate dalla mucina leucocitaria P-selectin glycoprotein ligand-1 (PSGL-1) e dalle
integrine leucocitarie α4β1 e αLβ2. Il trattamento dei topi con anticorpi bloccanti
queste molecole di adesione, ha indotto una drammatica riduzione delle crisi acute e
croniche indotte da pilocarpina. Anche la deficienza genetica di PSGL-1 funzionale o
di α1-3-fucosiltransferasi, enzimi coinvolti nella glicosilazione del PSGL-1, inibisce
le crisi. Per confermare ulteriormente un ruolo dei leucociti nell’induzione delle crisi,
abbiamo depleto i granulociti murini prima della somministrazione di pilocarpina e
abbiamo nuovamente osservato una consistente riduzione delle crisi acute e di quelle
croniche spontanee ricorrenti.
La rottura della barriera emato-encefalica (BBB), che, come dimostrato da diversi
recenti lavori, è noto aumentare l’eccitabilità neuronale, è stata drasticamente ridotta
negli animali trattati con anticorpi anti-integrina α4 o nei topi geneticamente
deficienti di PSGL-1 o di fucosiltransferasi. Questo suggerisce un legame
patogenetico tra: le interazioni tra leucociti e i vasi cerebrali, il danno di barriera e
l’insorgenza delle crisi. Abbiamo infine ottenuto dati che suggeriscono che l’epilessia
può essere correlata nei topi con elevate conte di leucociti in preparati
immunoistochimici di cervelli dopo crisi. Sono stati inoltre da noi analizzati anche
campioni di cervelli umani di pazienti epilettici dove abbiamo confermato una
maggiore abbondanza di leucociti nei cervelli epilettici rispetto ai controlli.
I nostri risultati indicano le interazioni tra leucociti ed endotelio cerebrale come un
target potenziale per la prevenzione ed il trattamento dell’epilessia.The present project represents an experimental study on the leukocyte recruitment in the induction and evolution of epilepsy. The mechanisms involved in the pathogenesis of epilepsy, a chronic neurological disorder that affects approximately one percent of the general world population, are not well understood1-3, but recent data suggest that inflammation may play a role in the pathogenesis of this disease. Leukocyte recruitment is a hallmark of and a point of therapeutic intervention in tissue inflammation, but a role for leukocyte-endothelial interactions in seizure pathogenesis has not been explored. Using a mouse model of epilepsy, pilocarpine induced, we show that seizures induce elevated expression of vascular cell adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and selectins on brain vessels. Intravital microscopy revealed enhanced granulocyte and TH1 lymphocyte interactions (rolling and arrest) in vivo with brain microvasculature after seizures, and these leukocyte-vascular interactions were mediated by the leukocyte mucin P-selectin glycoprotein ligand-1 (PSGL-1) and leukocyte integrins α4β1 and αLβ2. Treatment of mice with blocking antibodies dramatically reduced acute and chronic seizures induced by pilocarpine. Genetic deficiency of PSGL-1 or of the α1-3-fucosyltransferases, enzymes involved in the glycosylation of PSGL-1, also inhibited seizures. To further confirm a role for leucocytes in the induction of seizures we performed granulocytes depletion in mice before pilocarpine administration and we again observed a consistent reduction of acute and chronic spontaneous recurrent seizures. Blood-brain barrier (BBB) leakage, which is known to enhance neuronal excitability as shown in different recent articles, was induced by acute seizure activity, but it was drastically reduced in anti-α4 treated or PSGL-1 or FucT deficient animals, suggesting a pathogenetic link between leukocyte-vascular interactions, BBB damage and seizure generation. Finally, we provide data suggesting that epilepsy may be correlated in mice with elevated brain leukocyte counts after seizures. Consistent with the potential leukocyte involvement in epilepsy in humans, leukocytes were more abundant in brains of individuals with epilepsy than in controls. Our results suggest leukocyte-endothelial interaction as a potential target for the prevention and treatment of epilepsy.
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Wong, Donald Chun Kit. "Endothelial cell adhesion molecules: expression, upregulation and modulation of human brain microvessel endothelial cell-leukocyte interactions." Thesis, 1995. http://hdl.handle.net/2429/8732.
Full textAbstract:
Endothelial cells (EC) lining the cerebral blood vessels are responsible for the
formation and maintenance of a unique structural and functional barrier, the blood-brain
barrier (BBB), that normally prevents the movement of white blood cells from blood into
brain. Inflammatory and infectious diseases of the central nervous system (CNS),
including multiple sclerosis, encephalitis, meningitis and infarction, are characterized by
increased BBB permeability and infiltration of the brain by leukocytes. The mechanisms
that regulate the traffic of leukocytes across the BBB have not yet been elucidated. A
group of EC surface molecules called adhesion molecules, have been implicated in
interactions between inflammatory cells and extracerebral EC. They include E-selectin,
vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1
(ICAM-1) and platelet/endothelial cell adhesion molecule-1 (PECAM-1). Blocking these
molecules with antibodies (Abs) reduces leukocyte traffic across EC. One of these
molecules, ICAM-1, has been demonstrated in inflammatory CNS lesions.
The objective of this study was to investigate the expression and function of four
EC adhesion molecules in an in vitro model of the human BBB. The results indicate that
primary cultures of unstimulated human brain microvessel EC (HBMEC) form high
resistance monolayers and express low levels of E-selectin, VCAM-1 and ICAM-1 that
can be significantly upregulated following stimulation with cytokines and LPS.
PECAM-1 is strongly expressed by all cells constitutively. Treatment of HBMEC with
TNF increases monolayer permeability, and augments adhesion and migration of
polymorphonuclear leukocytes (PMN) and T-lymphocytes across the monolayers.
Adhesion of resting T-lymphocytes to activated endothelium is mediated by VCAM-1
and ICAM-1. ICAM-1, E-selectin and PECAM-1 participate in T-lymphocyte migration
across HBMEC monolayers. Adhesion of PMN to activated HBMEC is mediated by
ICAM-1 and E-selectin, while ICAM-1 is involved in the migration process.
Anti-adhesion molecule Abs reduce adhesion and/or migration but have no effect on the
increased endothelial permeability secondary to leukocyte migration. These studies
indicate that EC adhesion molecules, induced by cytokines, mediate cerebral
EC-leukocyte interactions which, in association with a concurrent increase in endothelial
permeability, may facilitate leukocyte traffic across the BBB in the early stages of CNS
inflammation.
36
Burns, Alan R. "Expression of leukocyte-endothelial adhesion molecules during acute inflammation in the lung." Thesis, 1993. http://hdl.handle.net/2429/2035.
Full textAbstract:
Neutrophil (PMN)-endothelial cell adhesion is a critical step in the response of PMNsto inflammation. In the systemic circulation, the leukocyte adhesion molecule, L-selectin, facilitates PMN adhesion to inflamed endothelium while CD11/CD18 is required for PMN emigration into extravascular tissues. An inducible endothelial ligand for CD18 is intercellular adhesion molecule-1 (ICAM-1). In the pulmonary circulation, PMNs emigrate by either a CD 18-independent or CD 18-dependent mechanism. The objective of this thesis was to quantitate and compare the surface expression of L-selectin, CD 18, and ICAM-1 during CD18-independent and CD 18-dependent emigration. Rabbits and mice received airway instillates of Streptococcus pneumoniae or Escherichia coil endotoxin to induce CD 18-independent or CD18-dependent emigration, respectively. Ultra thin cryosections of frozen lung were immunogold labeled for L-selectin, CD 18, and ICAM-1. Gold particles on the plasma membranes were quantitated by transmission electron microscopy. In rabbits, CD 18-independent emigration was associated with L-selectin down modulation and CD18 up modulation on intravascular PMNs.A similar alteration of L-selectin and CD18 expression was observed during CD 18-dependent emigration but only after PMNs emigrated into the interstitium. Alterations in L-selectin and CD18 expression were only observed on PMNs within the inflammatory focus. In mice, capillary endothelial ICAM-1 expression was unchanged during CD 18-independent emigration. During CD 18-dependent emigration, ICAM-1 expression increased 4.2-fold and this increase bordered on statistical significance, suggesting that the mechanism of adhesion may be regulated by the expression of endothelial rather than PMN adhesion molecules. ICAM-1 was also constitutively expressed on alveolar Type I but not Type II pneumocytes, the precursors of Type I cells. During pneumonia, Type II but not Type I pneumocytes showed increasedICAM-1 expression, suggesting that ICAM-1 expression represents an early event in differentiation preceding proliferation. In vitro studies of unstimulated human PMNs showed that L-selectin was preferentially expressed on the PMN surface microvilli that mediate initial contact with endothelium. During transendothelial migration, L-selectin down modulation is temporally correlated with PMN-endothelial contact. These studies describe the ultrastructural localization of adhesion molecules in normal and inflamed lungs and increase our understanding of the correlation between expression and function of adhesion molecules.
37
"Mechanisms of Methylglyoxal-elicited Leukocyte Recruitment." Thesis, 2014. http://hdl.handle.net/10388/ETD-2014-06-1585.
Full textAbstract:
Methylglyoxal (MG) is a reactive dicarbonyl metabolite formed during glucose, protein and fatty acid metabolism. In hyperglycemic conditions, an increased MG level has been linked to the development of diabetes and the accompanying vascular inflammation encountered at both macro- and microvascular levels. The present study explores the mechanisms of MG-induced leukocyte recruitment in mouse cremasteric microvasculature. Biochemical and intravital microscopy studies performed suggest that administration of MG (25 and 50 mg/kg) to mouse cremaster muscle tissue induces dose-dependent leukocyte recruitment in cremasteric vasculature with 84-92% recruited cells being neutrophils. MG treatment up-regulated the expression of endothelial cell (EC) adhesion molecules P-selectin, E-selectin and intercellular adhesion molecule-1 (ICAM-1) via the activation of nuclear factor-κB (NF-κB) signalling pathway and contributed to the increased leukocyte rolling flux, reduced leukocyte rolling velocity, and increased leukocyte adhesion, respectively. The inhibition of NF-κB blunted MG-induced endothelial adhesion molecule expression and thus attenuated leukocyte recruitment.
Further study of signalling pathways revealed that MG induced Akt-regulated transient glycogen synthase kinase 3 (GSK3) activation in ECs, which was responsible for NF-κB activation at early time-points (< 1 h). After MG activation for 1 h, the endothelial GSK3 activity was decreased due to the up-regulation of serum- and glucocorticoid-regulated kinase 1 (SGK1), which was responsible for maintaining NF-κB activity at later time-points. Silencing GSK3 or SGK1 attenuated P-selectin, E-selectin and ICAM-1 expression in ECs, and abated MG-induced leukocyte recruitment. SGK1 also promoted cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) activity which was partially involved in ICAM-1 expression. Silencing CREB blunted ICAM-1 expression while P-selectin and E-selectin levels remained unaffected. MG also induced GSK3 activation in isolated neutrophils after 30 min treatment, an effect that was not responsible for MG-elicited Mac-1 expression. These data suggest the sequential activation of GSK3 and SGK1 in ECs as the pivotal signalling mechanism in MG-elicited leukocyte recruitment.
Additionally, MG-treatment led to uncoupling of endothelial nitric oxide synthase (eNOS) following MG-induced superoxide generation in ECs. MG triggered eNOS uncoupling and hypophosphorylation associated with superoxide generation and biopterin depletion in EA.hy926 ECs. In cremaster muscle, as well as in cultured murine and human primary ECs, MG increased eNOS monomerization and decreased 5,6,7,8-tetrahydroboipterin (BH4)/total biopterin ratio, effects that were significantly mitigated by supplementation of BH4 or its precursor sepiapterin but not by NG-nitro-L-arginine methyl ester (L-NAME) or 5,6,7,8-tetrahydroneopterin (NH4). These observations confirm that MG administration triggers eNOS uncoupling. In murine cremaster muscle, MG triggered the reduction of leukocyte rolling velocity and the increases in rolling flux, adhesion, emigration and microvascular permeability. MG-induced leukocyte recruitment was significantly attenuated by supplementation of BH4 or sepiapterin or suppression of superoxide by L-NAME confirming the role of eNOS uncoupling in MG-elicited leukocyte recruitment. MG treatment further decreased the expression of guanosine triphosphate cyclohydrolase I in murine primary ECs, suggesting the impaired BH4 biosynthesis caused by MG.
Taken together, these data suggest that vascular inflammation and endothelial dysfunction occurring in diabetes may be linked to GSK3/SGK1 regulated adhesion molecule expression, as well as the uncoupling of eNOS evoked by elevated levels of MG. These findings not only provide a better understanding of the role of MG in the development of diabetic vascular inflammation, but also suggest the potential therapeutic targets for MG-sensitive endothelial dysfunction in diabetes.
38
Sampath, Rangarajan. "Shear stress mediated alterations in the expression of leukocyte adhesion receptors on human endothelial cells." Thesis, 1996. http://hdl.handle.net/1911/16919.
Full textAbstract:
Endothelial cells line the inner walls of blood vessels and are constantly subjected to hemodynamic shear forces due to flowing blood. Both in vivo and in vitro studies have shown that local fluid shear stress may play an important role both in normal inflammatory responses as well as in the initial development and progression of atherosclerosis. This study describes their contribution in regulating the expression of adhesion molecules ICAM-1, VCAM-1 and E-selectin on endothelial cells, with the goal of understanding the link between local fluid mechanics, inflammatory response and atherogenesis.
HUVEC monolayers exposed to different levels of controlled shear stress conditions were analyzed for the kinetics of expression of these adhesion molecules both in terms of gene transcription and surface protein expression. Results from the fluorescence analysis showed a transient increase in the surface expression of ICAM-1 upon exposure to shear stress (25 dynes/cm$\sp2$) for 12 hours that returned to basal levels within 24 hours. The messenger RNA (mRNA) levels for ICAM-1 also showed a transient increase after one to three hours of exposure to shear stress compared to matched control values. Subsequently, however, the mRNA levels decreased and within 6 hours dropped significantly below control values. VCAM-1 mRNA levels, however, decreased monotonically upon onset of flow at all values of shear stresses, and dropped well below basal levels within 6 hours. Neither molecule mRNA was present in detectable levels after 24 hours of flow. E-selectin mRNA levels appeared to be constant and comparable to control values for up to 6 hours after exposure to shear stress.
These studies also demonstrate altered response of shear preconditioned endothelial cells to subsequent activation with inflammatory mediators such as IL-1$\beta$. Both ICAM-1 and VCAM-1 mRNA levels were comparable in the 4 and 6 hour IL-1$\beta$ treated cells under both flow and static conditions. However, ICAM-1 levels were higher after 24 hours of IL-1$\beta$ under flow compared to similarly activated static cells whereas VCAM-1 levels were lower. ICAM-1 surface expression was also significantly (3- to 4-fold, p $<$ 0.02) higher under these conditions, while VCAM-1 did not change as a result of flow preconditioning. The observed differences between static and pre-sheared cells discussed here suggests that in vitro studies involving vascular cells should mimic as closely as possible the representative fluid mechanical environment of the region they are modeling.
39
Grooby, Warwick L. "Studies of endothelial and leukocyte cell adhesion molecules in renal transplantation / by Warwick L. Grooby." Thesis, 1996. http://hdl.handle.net/2440/18890.
Full textAbstract:
Erratum is pasted on back end paper.Bibliography: leaves 231-268.
xv, 268 leaves : ill. (chiefly col.) ; 30 cm.
This thesis examines the expression of cell adhesion molecules on both endothelial cells (ECs) and circulating leukocytes, and investigates the role of these molecules in renal allograft rejection. The aims of the study are to establish an ovine model of renal allograft transplantation, to generate monoclonal antibodies (mAbs) against ovine endothelial cell adhesion molecules, to examine the efficacy of the mAbs in prolonging the survival of the sheep renal allografts and to study the kinetics of expression of cell adhesion molecules (CAMs) during cellular activation 'in vitro' and 'in vivo' during the onset of allograft rejection.
Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 1996
40
Gao, Dingcheng [Verfasser]. "On the pathophysiological significance of CD154-CD40 mediated leukocyte endothelial cell interaction / vorgelegt von Gao Dingcheng." 2003. http://d-nb.info/968494919/34.
Full text
41
Huang, Ying-Ting, and 黃盈婷. "Investigation on Cellular Stimulations That Regulate Leukocyte Adhesion and ROS Production in Human Vascular Endothelial cells." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/57347154867458412594.
Full textAbstract:
碩士國立成功大學
微生物暨免疫學研究所
91
Vascular endothelial cells cover the internal surface of blood vessels and play important roles in the regulation of multiple vascular functions. The functions of vascular endothelial cells include modulation of vascular tone, production of cytokines, and interaction with circulating immune cells. Endothelial dysfunction leads to several pathological conditions including altered anti-coagulatory and anti-inflammatory properties of the endothelium and reduced regulation of vascular growth. In inflammation, multiple cellular stimulations (e.g. TNF-a, CRP, LPS, IFN-g, IL-1 and IL-6) activate endothelial cells to express adhesion molecules (e.g. ICAM-1 and VCAM-1). The expression of adhesion molecules on endothelial cells promotes circulating leukocytes to adhere and then transmigrate through vascular endothelium. Finally, the leukocytes reach the inflammatory sites and induce immune response. Endothelial dysfunction has been found in cardiovascular and inflammatory diseases including hypertension, atherosclerosis, diabetes, and allergic diseases. Excessive ROS was detected in the inflamed or damaged sites in these patients. More and more evidences suggest that oxidant stress reduces NO bioactivity, increases vascular endothelial permeability and promotes leukocyte adhesion. ROS also can serve as intracellular signaling molecules participating in cell growth and cytokine production. The regulation mechanisms of leukocyte adhesion and ROS production in inflamed endothelium are largely unknown. In order to investigate the cellular stimulations that regulate cell function, we treated human umbilical endothelial cells (HUVECs) with LPS, TNF-a, CRP, and IFN-g to mimic the inflammatory microenvironment. Our data showed that TNF-a and LPS induced high expression of ICAM-1 and VCAM-1 on HUVECs. However, CRP and IFN-g only had minor effects on adhesion molecule expression. When we combined TNF-a and CRP treatment, we found that CRP plays a role in enhancing TNF-a induced ICAM-1 and VCAM-1 expression on HUVECs. The mechanisms through which CRP modulates adhesion molecule expression and enhances other cytokines effects are still unknown. Furthermore, we prepared monoclonal antibodies against HUVECs to study how endothelial cell surface molecules are involved in the regulation of cell adhesion and ROS production. These anti-HUVEC mAbs (EN1-EN6) stained HUVECs, and some also stained other cell type. Their binding levels to HUVECs vary on cells treated with different stimulations. Some of them influenced leukocyte adhesion and induced ROS production on HUVECs. Interestingly, we found that an anti-HUVEC mAb (EN2) against ICAM-1 had the ability to enhance leukocyte-endothelial interaction in a ROS independent manner. Therefore, these anti-HUVEC mAbs will be useful tools to investigate endothelial functions including cellular adhesion and ROS production of HUVECs. These studies may facilitate the understanding of the regulation mechanisms on inflamed endothelial cells and lead to novel strategies in controlling inflammatory diseases.
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Cheng-Nan, Chen, and 陳政男. "Phenotypic Modulation of Vascular Smooth Muscle Cells and Its Contribution to Leukocyte Recruitment to Endothelial Cells under Disturbed Flow." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/86188710112377690816.
Full textAbstract:
博士國防醫學院
生命科學研究所
94
The early stage of atherogenesis develops at regions of arterial tree exposed to disturbed flow and involves adhesion of leukocytes (WBCs) to and their transmigration across endothelial cells (ECs), which are located in close proximity to smooth muscle cells (SMCs). SMCs located in normal arterial media exhibit a contractile phenotype, whereas SMCs in atherosclerotic plaques show a synthetic phenotype. Growth factor platelet-derived growth factor (PDGF)-BB and cytokine interleukin (IL)-1 contribute to progression of atherosclerotic lesions, where medial vascular SMCs change from their contractile to synthetic phenotype. The aims of this study were (1) to elucidate the role of PDGF-BB and IL-1 in phenotypic modulation of SMCs, and (2) to investigate the effects of disturbed flow and SMCs on the recruitment of three different types of WBCs [neutrophils, peripheral blood lymphocytes (PBLs), and monocytes] to ECs using our newly developed EC/SMC co-culture flow system. Human aortic SMCs grown on polymerized collagen showed time-dependent increases in the expression of contractile protein markers, including smooth muscle (SM)-actin, myosin heavy chain (SM-MHC), and calponin. Co-stimulation of these SMCs with PDGF-BB and IL-1 induced a sustained phosphorylation of their PDGF receptor (PDGFR)-, Akt and, p70S6K and down-regulated the expression of SM-actin, SM-MHC, and calponin. In contrast, the mTOR inhibitor rapamycin inhibited the PDGF-BB/IL-1-induced p70S6K phosphorylation and elevated these marker protein expressions. While adenoviruses expressing dominant-negative Akt eliminated the PDGF-BB/IL-1 effect on SM- actin, SM-MHC, and calponin expressions, constitutively active Akt mimicked the PDGF-BB/IL-1 effect. PDGF-BB/IL-1 co-stimulation induced a sustained association between PDGFR- and IL-1 receptor (IL-1R1). This receptor association was blocked by a PDGFR- neutralizing antibody (AF385), an IL-1R1 antagonist (IL-1ra), or a specific inhibitor of PDGFR- phosphorylation (AG1295), which consequently eliminated the PDGF-BB/IL-1-induced activation of PDGFR-/Akt/p70S6K and down-regulation of SMC marker protein expressions. When ECs were co-cultured with synthetic SMCs embedded in the collagen gel, the adhesion and transmigration of neutrophils, PBLs, and monocytes were increased in comparison to the monoculture ECs. Disturbed flow enhanced WBC recruitment to the EC/SMC, particularly in the reattachment area, where the rolling velocity of WBCs and their transmigration time were decreased, as compared with the other areas. Neutrophils, PBLs, and monocytes showed different subendothelial migration patterns under disturbed flow. Their movements were more random and shorter in distance in the reattachment area. Co-culture of ECs and SMCs induced their expressions of adhesion molecules and chemokines, which contributed to the increased WBC adhesion and transmigration. Our findings indicate that ECM components play an important role in the control of phenotypic properties of cultured SMCs. The findings also provide insights into the mechanisms contributing to phenotypic change of SMCs from contractile to synthetic state. Since SMCs in the plaques exert significant effects on ECs, the results from the use of our newly developed EC/SMC co-culture model may provide data for the understanding of the interaction between WBCs and the vessel wall (composed of ECs and SMCs) under the complex flow environments found in regions of prevalence of atherosclerotic lesions.
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Huang, Nuan-Ya, and 黃暖雅. "Effect of subcutaneous administration of endotoxin on formation of endothelial gaps, plasma leakage and leukocyte infiltration in rat hindpaw skin." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/78475967858460698184.
Full textAbstract:
碩士國立中山大學
生物科學系研究所
93
Endotoxin (lipopolysaccharide, LPS), is a constituent of the outer membrane of Gram-negative bacteria, activates macrophages to release cytokines that can cause local or systemic inflammatory responses. Plasma leakage and polymorphonuclear leukocyte infiltration are characteristic features of inflammation. This study examined the effect of LPS to induce subcutaneous inflammatory lesions, including time course of changes in plasma extravasation and level of leukocyte influx into the tissue interstitium. To investigate LPS-induced plasma leakage in the skin, LPS (500 μg/site) was administered by subcutaneous injection in the hindpaw skin. India ink (1 ml/kg) was used as tracer dye to measure the area density of ink-labeled leaky blood vessels. Our results showed that the postcapillary venules were leaking immediately at five minutes after LPS. The area density of India ink-labeled leaky vessels was 33.9 %±5.6 % (n=5) after the administration of LPS. The magnitude of plasma leakage was 2 times as the value of saline control (16.6 %±1.8 %, n=5). Plasma leakage peaked at 30 min (42.5 %±2.5 %, n=11) after LPS. Staining of the microvasculature by silver nitrate showed endothelial gap formation in venules and indicated the positive relevance to plasma leakage. Leukocytes (neutrophils and eosinophils) in hindpaw skin whole mounts were stained by a histochemical reaction for myeloperoxidase and the numbers of leukocytes quantified. LPS caused a severe response in leukocyte adhesion and accumulation. The number of leukocytes after LPS was 5 times as the number after saline. It is concluded that local injection of LPS in the skin caused formation of endothelial gaps and leukocyte infiltration that resulted in an increase in local vascular permeability.