25
views
0
recommends
+1 Recommend
1 collections
    0
    shares

      Call for Papers: Green Renal Replacement Therapy: Caring for the Environment

      Submit here before July 31, 2024

      About Blood Purification: 3.0 Impact Factor I 5.6 CiteScore I 0.83 Scimago Journal & Country Rank (SJR)

      • Record: found
      • Abstract: found
      • Article: found

      Vascular Leak in a Rat Model of Preeclampsia

      research-article

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background/Aims: Preeclampsia is a hypertensive disorder which develops de novo in women during pregnancy. The urinary excretion of the cardiotonic steroid, marinobufagenin (MBG), is increased prior to the development of hypertension. Preeclamptic patients are volume expanded but much of the excess salt and water appears to be located primarily in the interstitial space. Therefore, ‘capillary leak’ syndrome has been postulated in this disorder. Methods: We evaluated the vascular leakage in normal rats following MBG injection and in a rat model of human preeclampsia. We measured the changes in light intensity comparing that in the intravascular to the extravascular space by assessing ‘leak’ of fluorescein-labeled albumin (FITC-albumin) from mesenteric postcapillary venules. Results: FITC-albumin extravasation continued to increase in a time-dependent fashion after MBG infusion and was significant (p < 0.05) at 60 min of observation when compared to sham rats. We also observed a significant difference in ‘vascular leakage’ in preeclamptic rats compared to control non-pregnant and normal pregnant groups starting at 20 min after the FITC-albumin infusion. Conclusion: We propose that MBG is involved in the production of a ‘vascular leak’ in our rat model of preeclampsia.

          Related collections

          Most cited references21

          • Record: found
          • Abstract: found
          • Article: not found

          Endothelial dysfunction in preeclampsia.

          Several years ago the hypothesis was advanced that alterations of endothelial function could explain much of the pathophysiology of preeclampsia. Since that time, extensive data have been generated to support the hypothesis. Markers of endothelial activation can be demonstrated in women with overt preeclampsia. More importantly, many of these markers precede clinically evident disease and disappear with resolution of the disease. The original postulate was that materials produced by the poorly perfused placenta, which is characteristic of preeclampsia, entered the systemic circulation and altered endothelial cell activity. This was proposed to change vascular sensitivity to circulating pressors, activate coagulation, and reduce vascular integrity resulting in the pathophysiological changes of preeclampsia. As data have accumulated it has become increasingly evident that the insult to the endothelium is neither toxicity nor nonspecific injury but rather can better be characterized as endothelial activation. Candidate molecules have been suggested but not established. It seems likely that the responsible agent(s) will not be unique molecules but rather usual molecules present in excessive amounts. The hypothesis has been expanded to invoke involvement of the maternal constitution in the generation of endothelial injury and injurants. This concept is stimulated by the observation that reduced placental perfusion per se is not sufficient to generate the maternal syndrome. Women with growth-restricted fetuses frequently are not preeclamptic. Placental bed biopsies from not only growth-restricted but also prematurely born infants demonstrate failure of the physiological remodeling of decidual vessels responsible for the reduced placental perfusion of preeclampsia. This has led to the concept that preeclampsia is secondary to an interaction of reduced placental perfusion and maternal factors. Interestingly these maternal factors, obesity, insulin resistance, black race, hypertension, and elevated plasma homocysteine concentration are all risk factors for atherosclerosis in later life.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Circulating bufodienolide and cardenolide sodium pump inhibitors in preeclampsia.

            To determine plasma levels of the endogenous bufodienolide Na+/K+ ATPase inhibitor, marinobufagenin-like factor (MBG), in normotensive pregnancy and in preeclampsia, to compare changes of MBG with that of ouabain-like compound (OLC), and to characterize the purified MBG immunoreactive factor from preeclamptic plasma. Consecutive sample study. The levels of MBG and OLC compounds were measured in extracted plasma by solid phase fluoroimmunoassays. MBG and ouabain immunoreactive materials were partially purified from preeclamptic plasma via reverse-phase high-performance liquid chromatography (HPLC) and studied for their ability to cross react with MBG and ouabain antibodies, and to inhibit the Na+/K+ ATPase from human mesenteric arteries. Vasoconstrictor effect of authentic MBG was studied in isolated rings of human umbilical arteries. In 11 nonpregnant control individuals, plasma concentrations of MBG and OLC were 0.190+/-0.04 nmol/l and 0.297+/-0.037 nmol/l, respectively. In the third trimester of noncomplicated pregnancy (n = 6), plasma MBG increased (0.625+/-0.067 nmol/l, P<0.05), and OLC did not (0.32+/-0.07 nmol/l). In 15 patients with preeclampsia, plasma levels of both MBG and OLC increased dramatically (2.63+/-0.10 nmol/l and 0.697+/-0.16 nmol/l, respectively, P<0.01 versus both control groups). When fractionated by reverse phase HPLC, OLC was eluted by 18% acetonitrile, and MBG by 48% acetonitrile. Serially diluted samples of MBG and OLC immunoreactive materials from HPLC fractions reacted with MBG and ouabain antibody in solid phase immunoassay in a concentration dependent fashion. Authentic MBG caused contractile responses of isolated rings of human mesenteric arteries in a concentration-dependent manner. Similarly to the authentic MBG, HPLC purified MBG immunoreactive material from preeclamptic plasma inhibited Na+/K+ ATPase purified from human mesenteric artery. Our observations demonstrate the coexistence of two endogenous cardiotonic steroids in preeclamptic plasma, a more polar OLC and a less polar MBG-like compound. Substantial increases in plasma OLC and MBG immunoreactivity in preeclampsia, along with the vasoconstrictor properties of authentic MBG and Na+,K+ ATPase inhibitory activity of human MBG immunoreactive factor, suggest, that in preeclampsia, plasma concentrations of MBG are enough to substantially inhibit the sodium pump in cardiovascular tissues, and are in accordance with the views attributing endogenous digitalis-like factors a pathogenic role in the preeclamptic hypertension.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Activated neutrophils induce hyperpermeability and phosphorylation of adherens junction proteins in coronary venular endothelial cells.

              The endothelial adherens junction is formed by complexes of transmembrane adhesive proteins, of which beta-catenin is known to connect the junctional protein vascular endothelial (VE)-cadherin to the cytoskeleton and to play a signaling role in the regulation of junction-cytoskeleton interaction. In this study, we investigated the effect of neutrophil activation on endothelial monolayer integrity and on beta-catenin and VE-cadherin modification. Treatment of cultured bovine coronary endothelial monolayers with C5a-activated neutrophils resulted in an increase in permeability as measured by albumin clearance across the monolayer. Furthermore, large scale intercellular gap formation was observed in coincidence with the hyperpermeability response. Immunofluorescence analysis showed that beta-catenin and VE-cadherin staining changed from a uniform distribution along the membrane of control cells to a diffuse pattern for both proteins and finger-like projections for beta-catenin in neutrophil-exposed monolayers. Correlatively, there was an increase in actin stress fiber formation in treated cells. Finally, beta-catenin and VE-cadherin from neutrophil-treated endothelial cells showed a significant increase in tyrosine phosphorylation. Our results are the first to link neutrophil-mediated changes in adherens junctions with intercellular gap formation and hyperpermeability in microvascular endothelial cells. These data suggest that neutrophils may regulate endothelial barrier function through a process conferring conformational changes to beta-catenin and VE-cadherin.
                Bookmark

                Author and article information

                Journal
                AJN
                Am J Nephrol
                10.1159/issn.0250-8095
                American Journal of Nephrology
                S. Karger AG
                0250-8095
                1421-9670
                2009
                July 2009
                05 February 2009
                : 30
                : 1
                : 26-33
                Affiliations
                aDivision of Nephrology and Hypertension, Department of Medicine, and bDepartment of Surgery, Texas A&M Health Science Center/Scott & White, Temple, Tex., USA
                Article
                193220 PMC2821446 Am J Nephrol 2009;30:26–33
                10.1159/000193220
                PMC2821446
                19194101
                f2cafdc2-89db-4407-b8e5-c6b0d25be22e
                © 2009 S. Karger AG, Basel

                Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

                History
                : 20 November 2008
                : 08 December 2008
                Page count
                Figures: 4, Tables: 1, References: 29, Pages: 8
                Categories
                Original Report: Laboratory Investigation

                Cardiovascular Medicine,Nephrology
                Capillary leak,Vascular permeability,Marinobufagenin,Preeclampsia

                Comments

                Comment on this article