Antithrombotic Effects of Recombinant Human, Active Site–Blocked Factor VIIa in a Rabbit Model of Recurrent Arterial Thrombosis

From the Department of Internal Medicine (P.G., M.R., P.C., D.D'A., A.S., A.R., C.B., N.C., F.V., M.C., M.C.), Division of Cardiology, 2nd School of Medicine, University of Naples (Italy), and the Department of Vessel Wall Biology (M.E.), Novo Nordisk A/S, Gentofte, Denmark.

Correspondence to Paolo Golino, MD, PhD, Division of Cardiology, University of Naples "Federico II," via Sergio Pansini 5, 80131 Naples, Italy. E-mail golino{at}ds.cised.unina.it

Abstract—The extrinsic coagulation pathway is activated when circulating factor VII (FVII) gains access to tissue factor (TF) exposed as a consequence of vascular injury. Increasing evidence indicates that this TF-dependent activation of the coagulation plays an important role in the pathophysiology of intravascular thrombus formation. In the present study, we tested the effects of recombinant human, active site–blocked activated FVII (FVIIai) in a rabbit model of carotid artery thrombosis. Cyclic flow variations (CFVs), due to recurrent thrombus formation, were obtained in stenotic rabbit carotid arteries with endothelial injury. Carotid blood flow velocity was measured by a Doppler flow probe. After 30 minutes of CFVs, the animals received FVIIai (100 µg · kg^-1 · min^-1 intracarotid infusion for 10 minutes, n=9). If CFVs were abolished, animals were followed for 30 additional minutes, after which recombinant human activated FVII (FVIIa) was infused into the carotid artery (100 µg · kg^-1 · min^-1 for 10 minutes) to determine whether FVIIai could be displaced from TF by FVIIa, thus restoring CFVs. To establish the duration of action of FVIIai, an additional group of animals received FVIIai at the same dose as above, and after CFVs were inhibited, they were followed until CFVs were restored or for up to 6 hours. To determine whether CFVs could be restored by epinephrine after their abolition with FVIIai, increasing doses of epinephrine were administered to a third group of 6 animals. FVIIai abolished CFVs in 8 of 9 rabbits (P<.01). This effect was reversible, as FVIIa administration restored CFVs in all animals. Prothrombin times and activated partial thromboplastin times did not change significantly throughout the study. One single 10-minute infusion exerted complete antithrombotic effects for at least 6 hours, despite the fact that at this time point, plasma FVIIai levels were well below threshold concentrations. Epinephrine restored CFVs in 3 of 6 animals in which CFVs were inhibited by FVIIai. FVIIai exerts potent antithrombotic effects in this model; these effects were prolonged even after FVIIai was almost completely cleared from the circulation, probably as a result of the tight binding of FVIIai to TF. Thus, FVIIai might represent an antithrombotic substance of potential interest.

Key Words: thrombosis • tissue factor • factor VII • active site–blocked activated factor VII

This article has been cited by other articles:

				L. Wang, C. Miller, R. F. Swarthout, M. Rao, N. Mackman, and M. B. Taubman Vascular smooth muscle-derived tissue factor is critical for arterial thrombosis after ferric chloride-induced injury Blood, January 15, 2009; 113(3): 705 - 713. [Abstract] [Full Text] [PDF]

				R. A. Shirk and G. P. Vlasuk Inhibitors of Factor VIIa/Tissue Factor Arterioscler Thromb Vasc Biol, September 1, 2007; 27(9): 1895 - 1900. [Abstract] [Full Text] [PDF]

				H. Zhou, A. S. Wolberg, and R. A. S. Roubey Characterization of monocyte tissue factor activity induced by IgG antiphospholipid antibodies and inhibition by dilazep Blood, October 15, 2004; 104(8): 2353 - 2358. [Abstract] [Full Text] [PDF]

				P. Cirillo, G. Cali, P. Golino, P. Calabro, L. Forte, S. D. Rosa, M. Pacileo, M. Ragni, F. Scopacasa, L. Nitsch, et al. Tissue Factor Binding of Activated Factor VII Triggers Smooth Muscle Cell Proliferation via Extracellular Signal-Regulated Kinase Activation Circulation, June 15, 2004; 109(23): 2911 - 2916. [Abstract] [Full Text] [PDF]

				P. Golino, A. Ravera, M. Ragni, P. Cirillo, O. Piro, and M. Chiariello Involvement of Tissue Factor Pathway Inhibitor in the Coronary Circulation of Patients With Acute Coronary Syndromes Circulation, December 9, 2003; 108(23): 2864 - 2869. [Abstract] [Full Text] [PDF]

				S. M. Bates and J. I. Weitz Emerging Anticoagulant Drugs Arterioscler Thromb Vasc Biol, September 1, 2003; 23(9): 1491 - 1500. [Abstract] [Full Text] [PDF]

				M. Fattorutto, H. Deckmyn, K. Vanhoorelbeke, and H. Kotze A modified Folts model or the original Folts model to evaluate new antithrombotics? Blood, January 15, 2003; 101(2): 782 - 782. [Full Text] [PDF]

				E. I. Lev, J. D. Marmur, M. Zdravkovic, J. I. Osende, J. Robbins, J. A. Delfin, M. Richard, E. Erhardtsen, M. S. Thomsen, A. M. Lincoff, et al. Antithrombotic Effect of Tissue Factor Inhibition by Inactivated Factor VIIa: An Ex Vivo Human Study Arterioscler Thromb Vasc Biol, June 1, 2002; 22(6): 1036 - 1041. [Abstract] [Full Text] [PDF]

				A. H.M Moons, M. Levi, and R. J.G Peters Tissue factor and coronary artery disease Cardiovasc Res, February 1, 2002; 53(2): 313 - 325. [Abstract] [Full Text] [PDF]

				P. Golino, P. Cirillo, P. Calabro', M. Ragni, D. D'Andrea, E. V. Avvedimento, F. Vigorito, N. Corcione, F. Loffredo, and M. Chiariello Expression of exogenous tissue factor pathway inhibitor in vivo suppresses thrombus formation in injured rabbit carotid arteries J. Am. Coll. Cardiol., August 1, 2001; 38(2): 569 - 576. [Abstract] [Full Text] [PDF]

				U. Rauch, J. I. Osende, V. Fuster, J. J. Badimon, Z. Fayad, and J. H. Chesebro Thrombus Formation on Atherosclerotic Plaques: Pathogenesis and Clinical Consequences Ann Intern Med, February 6, 2001; 134(3): 224 - 238. [Abstract] [Full Text] [PDF]

				P. M. Mrozikiewicz, I. Cascorbi, S. Ziemer, M. Laule, C. Meisel, V. Stangl, W. Rutsch, K. Wernecke, G. Baumann, I. Roots, et al. Reduced procedural risk for coronary catheter interventions in carriers of the coagulation factor VII-Gln353 gene J. Am. Coll. Cardiol., November 1, 2000; 36(5): 1520 - 1525. [Abstract] [Full Text] [PDF]

				M. Ragni, P. Golino, P. Cirillo, A. Scognamiglio, O. Piro, N. Esposito, C. Battaglia, F. Botticella, P. Ponticelli, L. Ramunno, et al. Endogenous Tissue Factor Pathway Inhibitor Modulates Thrombus Formation in an In Vivo Model of Rabbit Carotid Artery Stenosis and Endothelial Injury Circulation, July 4, 2000; 102(1): 113 - 117. [Abstract] [Full Text] [PDF]

				P. Golino, M. Ragni, P. Cirillo, A. Scognamiglio, A. Ravera, C. Buono, A. Guarino, O. Piro, C. Lambiase, F. Botticella, et al. Recombinant human, active site-blocked factor VIIa reduces infarct size and no-reflow phenomenon in rabbits Am J Physiol Heart Circ Physiol, May 1, 2000; 278(5): H1507 - H1516. [Abstract] [Full Text] [PDF]