Thromb Haemost 1998; 80(03): 481-487
DOI: 10.1055/s-0037-1615233
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Heparin Regulates ICAM-1 Expression in Human Endothelial Cells: An Example of Non-Cytokine-Mediated Endothelial Activation

Authors

  • Steven J. Miller

    1   From the Division of Experimental Pathology, Methodist Research Institute, Inc., Clarian Health Partners, Inc., Indianapolis, Indiana, USA
  • A. M. Hoggatt

    1   From the Division of Experimental Pathology, Methodist Research Institute, Inc., Clarian Health Partners, Inc., Indianapolis, Indiana, USA
  • W. Page Faulk

    1   From the Division of Experimental Pathology, Methodist Research Institute, Inc., Clarian Health Partners, Inc., Indianapolis, Indiana, USA
Further Information

Publication History

Received 11 September 1997

Accepted after resubmission 19 May 1998

Publication Date:
08 December 2017 (online)

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Summary

Activated endothelial cells up-regulate the expression of several molecules on their plasma membranes, including intercellular adhesion molecule-1 (ICAM-1). The role of heparin in regulating endothelial cell gene expression is unclear. We thus have investigated the ability of heparin to regulate ICAM-1 gene expression by using flow cytometry and the ribonuclease protection assay with human umbilical vein and aortic endothelial cells cultured in growth medium supplemented with 90 μg/ml heparin (heparin-sufficient, HS) or in growth medium without added heparin (heparin-deficient, HD). We found that HD medium increased plasma membrane protein and mRNA for ICAM-1 but not for HLA-DR, even though both ICAM-1 and HLA-DR protein and mRNA were inducible by gamma interferon (IFN-γ). In addition, phorbol ester and IFN-γ increased the expression of plasma membrane ICAM-1 or ICAM-1 and HLA-DR, respectively, more in HD medium than in HS medium. We found that the HD-mediated increase of ICAM-1 mRNA was reversible by the addition of heparin, and that the half-life of ICAM-1 mRNA was the same in both HS- and HD-treated cells. Also, heparin was found to suppress increases in ICAM-1 mRNA at a concentration as low as 5 μg/ml. These findings indicate that heparin deficiency induces endothelial activation characterized by increased ICAM-1, and that such induction is not dependent on cytokines or endotoxin. The modulation of ICAM-1 expression by heparin appears to occur at the transcriptional level. Thus, heparin may have a role in regulating endothelial function by affecting the expression of ICAM-1, thereby impacting upon the trans-endothelial trafficking of leukocytes.