Tissue factor activity in whole blood
- 1 April 2005
- journal article
- Published by American Society of Hematology in Blood
- Vol. 105 (7), 2764-2770
- https://doi.org/10.1182/blood-2004-09-3567
Abstract
Tissue factor (TF) is an integral membrane protein essential for hemostasis. During the past several years, a number of studies have suggested that physiologically active TF circulates in blood at concentrations greater than 30 pM either as a component of blood cells and microparticles or as a soluble plasma protein. In our studies using contact pathway–inhibited blood or plasma containing activated platelets, typically no clot is observed for 20 minutes in the absence of exogenous TF. An inhibitory anti-TF antibody also has no effect on the clotting time in the absence of exogenous TF. The addition of TF to whole blood at a concentration as low as 16 to 20 fM results in pronounced acceleration of clot formation. The presence of potential platelet TF activity was evaluated using ionophore-treated platelets and employing functional and immunoassays. No detectable TF activity or antigen was observed on quiescent or ionophore-stimulated platelets. Similarly, no TF antigen was detected on mononuclear cells in nonstimulated whole blood, whereas in lipopolysaccharide (LPS)–stimulated blood a significant fraction of monocytes express TF. Our data indicate that the concentration of physiologically active TF in non–cytokine-stimulated blood from healthy individuals cannot exceed and is probably lower than 20 fM.Keywords
This publication has 60 references indexed in Scilit:
- Cell‐derived microparticles in synovial fluid from inflamed arthritic joints support coagulation exclusively via a factor VII–dependent mechanismArthritis & Rheumatism, 2002
- Elevated Numbers of Tissue-Factor Exposing Microparticles Correlate With Components of the Metabolic Syndrome in Uncomplicated Type 2 Diabetes MellitusCirculation, 2002
- The presence and release of tissue factor from human plateletsPlatelets, 2002
- Adenosine Inhibits Tissue Factor Expression by LPS-stimulated Human Monocytes: Involvement of the A3 Adenosine ReceptorThrombosis and Haemostasis, 2002
- Tissue factor activity in human monocytes is regulated by plasma: implications for the high and low responder phenomenonBritish Journal of Haematology, 2001
- Enhanced generation of monocyte tissue factor and increased plasma prothrombin fragment1+2 levels in patients with polycythemia vera: Mechanism of activation of blood coagulationAmerican Journal of Hematology, 1997
- Astrocytes are the primary source of tissue factor in the murine central nervous system. A role for astrocytes in cerebral hemostasis.JCI Insight, 1993
- Proteolytic activation of human factors IX and X by recombinant human factor VIIa: effects of calcium, phospholipids, and tissue factorBiochemistry, 1990
- Localization of human tissue factor antigen by immunostaining with monospecific, polyclonal anti-human tissue factor antibodyThrombosis Research, 1990
- Isolation of cDNA clones coding for human tissue factor: primary structure of the protein and cDNA.Proceedings of the National Academy of Sciences, 1987