This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mackman, N. Search for Related Content PubMed PubMed Citation Articles by Mackman, N. Related Collections Cardiovascular Coagulation

---

CARDIOVASCULAR ANESTHESIOLOGY

The Role of Tissue Factor and Factor VIIa in Hemostasis

From the Division of Hematology/Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Address correspondence and reprint requests to Nigel Mackman, PhD, Division of Hematology/Oncology, Department of Medicine, University of North Carolina at Chapel Hill, 915 Mary Ellen Jones, Campus Box 7035, Chapel Hill, NC 27599-7035. Address e-mail to nmackman{at}med.unc.edu.

Abstract

Tissue factor (TF) is a transmembrane receptor for Factor VII/VIIa (FVII/VIIa). It is constitutively expressed by cells surrounding blood vessels. The endothelium physically separates this potent "activator" from its circulating ligand FVII/FVIIa and prevents inappropriate activation of the clotting cascade. Breakage of the endothelial barrier leads to exposure of extravascular TF and rapid activation of the clotting cascade. TF is also expressed in certain tissues, such as the heart and brain, and provides additional hemostatic protection to these tissues. Small amounts of TF are also present in blood in the form of microparticles, which are small membrane vesicles derived from activated and apoptotic cells. Levels of microparticle TF increase in a variety of diseases, such as sepsis and cancer, and this so-called "blood-borne" TF may contribute to thrombosis associated with these diseases. Recombinant FVIIa has been developed as an effective hemostatic drug for the treatment of hemophilia patients with inhibitory antibodies. In addition, it is used for patients with bleeding that do not respond to conventional therapy. However, the mechanism by which recombinant FVIIa restores hemostasis has not been clearly defined. In conclusion, the TF:FVIIa complex is essential for hemostasis and recombinant FVIIa is an effective hemostatic drug.

This article has been cited by other articles:

				M. Delvaeye and E. M. Conway Coagulation and innate immune responses: can we view them separately? Blood, September 17, 2009; 114(12): 2367 - 2374. [Abstract] [Full Text] [PDF]