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      Connexin43 Gene Expression in the Rabbit Arterial Wall: Effects of Hypercholesterolemia, Balloon Injury and Their Combination

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          Abstract

          The specialized functions of endothelium require intercellular communication between endothelial cells within the monolayer, and between endothelium and other cells present in the vessel wall. This is accomplished by a combination of paracrine soluble mediators and direct gap-junctional intercellular communication (GJIC) mediated by a family of connexin proteins. A prominent connexin expressed by vascular cells in vivo and in vitro is connexin 43 (Cx43). We have investigated the in vivo gene regulation of Cx43 in the context of vascular pathology, as a result of mechanical injury, hypercholesterolemia or both. The aortoiliac bifurcation in the rabbit was examined following three types of insult: (1) diet-induced hypercholesterolemia resulting in macrophage-rich fatty streak lesions, (2) mechanical, stretch-denudation injury resulting in intimal smooth muscle cell (SMC) proliferation and (3) mechanical injury superimposed on hypercholesterolemia resulting in a complex vascular lesion having characteristics of both interventions. The normal rabbit iliac artery expressed approximately equal levels of Cx43 mRNA in the medial SMC layers and in the endothelium. In hypercholesterolemia-induced atherosclerosis, Cx43 expression was most prominent in macrophage foam cells even though normocholesterolemic precursor monocytes did not express Cx43 mRNA. Antibodies directed specifically to Cx43 protein confirmed the expression of macrophage gap junction protein in these cells. Medial SMC in hypercholesterolemia exhibited less Cx43 than their normal counterparts in control animals. Mechanical injury in the absence of hypercholesterolemia resulted in intimal thickening in which Cx43 expression in the intimal SMC was equivalent to that in the subjacent medial SMC, both being approximately equivalent to normal uninjured rabbit medial SMC expression. Cell-specific expression of Cx43 in combined mechanical injury/hypercholesterolemia was similar to that observed in hypercholesterolemia alone: Cx43 upregulation in macrophages, while medial SMC were downregulated. Normo- and hypercholesterolemic alveolar macrophages of the lung and Kupffer cells of the liver did not exhibit induction of Cx43 mRNA, nor did macrophages isolated from peritoneal or bronchial lavage fluid of the same animals. This work extends our previous finding of Cx43 upregulation in human atherectomy tissue and demonstrates that atherosclerotic lesions in situ, in a controlled animal model of atherosclerosis, exhibit cell-specific changes in Cx43 gene expression. Changes in medial SMC migration, proliferation and phenotype, as well as enhanced interactions between adherent/infiltrating monocytes and endothelium may be related to modified GJIC pathways in the vessel wall.

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          Author and article information

          Journal
          JVR
          J Vasc Res
          10.1159/issn.1018-1172
          Journal of Vascular Research
          S. Karger AG
          1018-1172
          1423-0135
          1997
          1997
          24 September 2008
          : 34
          : 1
          : 19-30
          Affiliations
          Departments of aSurgery and bPathology, Pritzker School of Medicine, University of Chicago, Ill., USA
          Article
          159198 J Vasc Res 1997;34:19–30
          10.1159/000159198
          9075822
          © 1997 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.

          Page count
          Pages: 12
          Categories
          Research Paper

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