Thromb Haemost 2006; 95(03): 462-468
DOI: 10.1160/TH05-06-0432
Platelets and Blood Cells
Schattauer GmbH

Truncated and microparticle-free soluble tissue factor bound to peripheral monocytes preferentially activate factor VII

Mohammad M. H. Khan*
1   From the Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
,
Takashi Hattori*
1   From the Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
,
Stefan Niewiarowski
2   The Sol Sherry Thrombosis Research Center, Hematology Division of the Department of Medicine, Temple University, Philadelphia, Pennsylvania, USA
,
L. Henry Edmunds Jr.
1   From the Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
,
Robert W. Colman
2   The Sol Sherry Thrombosis Research Center, Hematology Division of the Department of Medicine, Temple University, Philadelphia, Pennsylvania, USA
› Author Affiliations

Financial support: This work was supported by HL 47186 from the National Heart Lung Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
Further Information

Publication History

Received 17 June 2005

Accepted after resubmission 16 January 2006

Publication Date:
29 November 2017 (online)

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Summary

Soluble plasma tissue factor (TF) circulates in picomolar concentrations in healthy individuals and increases in a wide spectrum of diseases. This study tests the hypothesis that both truncatedTF (rsTF) or soluble plasmaTF (pTF) in low concentration combine with monocytes or platelets to convert factorVII (fVII) to fVIIa. Both rsTF (33 kDa) and pTF (47 kDa), obtained from pericardial wounds of patients having cardiac surgery using cardiopulmonary bypass (CPB), were studied in association with blood cells and TF-bearing microparticles. Tissue factor was measured by ELISA. RsTF binds to erythrocytes, platelets, mononuclear cells and polymorphoneutrophils. The rate of fVII conversion with rsTF (1–103 nM) is highest with mononuclear cells, less with platelets, minimal with polymorphoneutrophils and undetectable with erythrocytes. Either stimulated or unstimulated mononuclear cells or platelets in the presence of 3.5 pM rsTF or pTF convert fVII (10 nM) to fVIIa, but the amounts of fVIIa produced differ. When leukocytes or platelets are absent, microparticles associated with 3.5 pM TF antigen derived from pericardial wound plasma do not activate fVII. Stimulated mononuclear cells convert nearly all available fVII (10 nM) to fVIIa with 3.5 nM pTF; unstimulated mononuclear cells convert small amounts of fVII with 1 pM rsTF. In all comparisons mononuclear cells more efficiently convert fVII to fVIIa than do platelets. This study shows that stimulated mononuclear cells provide the most efficient platform for activation of rsTF or pTF at low concentrations of TF antigen.

* Drs. Khan and Hattori contributed equally to this project.


+ Drs. Colman and Edmunds are equal senior authors.