Evidence for the Presence of Tissue Factor Activity on Subendothelium

• Published in: Blood Vol. 73; no. 4; pp. 968 - 975
• Main Authors: Weiss, Harvey J., Turitto, Vincent T., Baumgartner, Hans R., Nemerson, Yale, Hoffmann, Thomas
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01.03.1989; The Americain Society of Hematology
• Subjects: Animals; Aorta; Biological and medical sciences; Blood Coagulation Factors - physiology; Blood vessels and receptors; Endothelium, Vascular - physiology; Fundamental and applied biological sciences. Psychology; Humans; Rabbits; Thromboplastin - physiology; Umbilical Arteries; Vertebrates: cardiovascular system; Human; Blood coagulation; Tissue factor; Rabbit; Activation; Umbilical artery; Lagomorpha; Artery; Endothelium; Vertebrata; Mammalia; Blood vessel; Aorta; Circulatory system
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V73.4.968.968

By a variety of methods, tissue factor activity was demonstrated in the subendothelium of rabbit aorta and human umbilical artery. In one method, everted segments of de-endothelialized vessels were mounted in an annular perfusion chamber and the subendothelial surface was exposed to nonanticoagulated human blood under controlled flow. Procoagulant activity was assessed by measuring fibrin deposition on subendothelium and fibrinopep-tide A (FPA) levels in post chamber blood. Both fibrin deposition and FPA were decreased with rabbit vessel segments exposed (at a shear rate of 650 seconds-1) to blood from patients with factor VII deficiency and with umbilical artery segments (at shear rates of 90 to 180 seconds-1) that had been pretreated with a monoclonal antibody to human tissue factor. In a second method, everted umbilical artery segments were mounted on a stir bar and the subendothelial surface was exposed, with stirring, to plasma or purified coagulation factors. The capacity of the surface to clot plasma on addition of calcium was inhibited by the antibody to tissue factor. The surface also activated purified 3H-factor X in the presence of factor Vila, but not in its absence, and this surface property was almost entirely eliminated by pretreating the vessel segments with antitissue factor. Tissue factor activity in subendothelium could play a role in both the arrest of bleeding and in promoting the formation of thrombi at sites of vascular injury.