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Keywords:

  • coagulation;
  • Factor VII;
  • tissue factor;
  • tissue factor pathway inhibitor

Abstract

  1. Top of page
  2. Abstract
  3. Activation of the coagulation pathway
  4. Tissue factor pathway inhibitor
  5. FVIIa inhibitors
  6. Competing Interests
  7. Acknowledgments
  8. REFERENCES

Initiation of blood coagulation occurs mainly through tissue factor (TF) that becomes exposed to blood following vascular injury. Cell-associated TF binds to the serine protease FVIIa and initiates a cascade of amplified zymogen activation reactions leading to thrombus formation. As TF-FVIIa directed inhibitors might achieve anticoagulant efficacy without significantly interfering with normal haemostasis, the TF-FVIIa complex is an interesting target in thrombosis-related disease. Various approaches have been used to inhibit the TF-FVIIa complex including active site-inhibited FVIIa, TF antibodies, tissue factor pathway inhibitor (TFPI), naturally occurring inhibitors, peptide exosite inhibitors and active site inhibitors. Several experimental studies using these inhibitors have displayed promise. However, none of these TF/FVIIa inhibitors has reached clinical testing. Further studies are required to evaluate the clinical efficacy of these novel inhibitors.


Activation of the coagulation pathway

  1. Top of page
  2. Abstract
  3. Activation of the coagulation pathway
  4. Tissue factor pathway inhibitor
  5. FVIIa inhibitors
  6. Competing Interests
  7. Acknowledgments
  8. REFERENCES

After vessel wall injury membrane bound tissue factor (TF) is exposed to circulating blood and forms a complex with the zymogen FVIIa. The TF-FVII complex is converted to the enzymatically active TF-FVIIa complex by FXa or autocatalytically by TF-FVIIa [1]. In addition to vascular TF, TF may also originate from circulating blood in the form of encrypted TF carried by microparticles [2–4]. Also, TF has been identified in the open canicular system and alpha-granules of platelets [5]. The activity of the TF-FVIIa complex is influenced by the membrane composition as its proteolytic activity requires high concentrations of anionic phospholipids. The TF-FVII/FVIIa complex subsequently activates FX into FXa and FIX into FIXa (extrinsic pathway), a process that is enhanced within membrane areas with high phosphatidylserine content [6]. Generated FXa initially converts limited amounts of prothrombin into thrombin sufficient to activate FVIII, FV and FXI (Figure 1). The FXa activity is restricted to the surface of TF positive cells as any FXa that diffuses off the cell surface is immediately inhibited by tissue factor pathway inhibitor (TFPI) and antithrombin (AT). Thrombin generated by FXa then activates platelets, exposes negatively charged phospholipids and thereby induces a thrombin burst (Figure 1) [7]. FX can also be activated to FXa by a different pathway: the complex of FIXa with its cofactor FVIIIa (intrinsic Xase complex) where FIX is activated to FIXa by FXIa via the intrinsic pathway (Figure 1). Thus, FIXa and FXa represent points of convergence for the intrinsic and extrinsic pathways. FXa in complex with its cofactor FVa (prothrombinase complex) activates prothrombin to thrombin ultimately resulting in the formation of a fibrin clot. Thrombin also serves to amplify coagulation further by activation of cofactors FV and FVIII and zymogen FXI in the intrinsic pathway (Figure 1). Moreover, thrombin activates platelets leading to platelet activation which is necessary for the formation of a haemostatic plug [1]. This results in a tightly regulated balance between normal clot formation and dissolution (haemostasis) and pathogenic clot formation (thrombosis). The TF-FVIIa complex is an interesting target in thrombosis-related disease because TF-FVIIa directed inhibitors might achieve anticoagulant efficacy without significantly interfering with normal haemostasis [8]. This may be because of the fact that intravascular TF is inhibited at lower concentrations than vascular TF which requires higher concentrations for inhibition and mainly contributes to haemostasis [2]. This is of particular importance as the challenge remains to achieve optimal anticoagulation without bleeding complications.

image

Figure 1. TF-dependent activation of the coagulation cascade: direct or indirect through FIXa/FVIIa activation

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Various studies identified TF as an important player in atherosclerotic disease [9]. In particular, in acute coronary syndromes TF is found on smooth muscle cells and macrophages within the plaque [10–12] and in the circulating blood [13–15] and thus may be a novel target to inhibit thrombotic complications. Moreover, activation of the TF-FVIIa pathway may contribute to myocardial reperfusion injury [16], restenosis [17], venous thrombosis [18] and inflammatory diseases [19]. In addition to the activation of coagulation, TF-FVIIa may contribute to vascular remodelling, cancer progression and angiogenesis through activation of signalling pathways [20, 21].

The complex nature of the TF-FVIIa interaction and procoagulant activity offers a variety of approaches to inhibit TF-FVIIa function (Figure 2). These include the endogenous inhibitor tissue factor pathway inhibitor (TFPI), modified versions of FVIIa and TF, antibodies directed against TF and the FVII/FVIIa complex, naturally occurring inhbitors, exosite and active site inhibitors of FVIIa.

image

Figure 2. Approaches for inhibition of the TF-FVIIa complex: TF-FVIIa complex is shown on a phopsholipid membrane (grey) showing the FVIIa (green) and TF (blue) domains and potential sites for inhibition

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Tissue factor pathway inhibitor

  1. Top of page
  2. Abstract
  3. Activation of the coagulation pathway
  4. Tissue factor pathway inhibitor
  5. FVIIa inhibitors
  6. Competing Interests
  7. Acknowledgments
  8. REFERENCES

Tissue factor pathway inhibitor is a Kunitz-type proteinase inhibitor and is primarily expressed in endothelial cells. The anticoagulant function of TFPI involves the FXa-dependent inhibition of TF-FVIIa, thereby directly inhibiting the initiation phase of coagulation. Although FXa is not required for inhibition of TF-FVIIa, TFPI inactivates the majority of FXa bound to TF-FVIIa. Therefore, TFPI evolves its anticoagulant function once the early stages of the pathway have been initiated. The first stage in the inhibitory function of TFPI involves the reversible inhibition of FXa via ionic binding of FXa to full-length plasma or cell-associated TFPI involving the P1 residue (Arg107) in the second Kunitz-type domain (TFPI K2). This interaction is enhanced by the presence of first (K1), the third Kunitz-type domain (K3) or the basic carboxyl-region. Once FXa is assembled in the prothrombinase complex with FVa it is protected from TFPI inhibition, because of competition for the active site of FXa with prothrombin which is present at much higher concentrations than TFPI. The second stage in the inhibition of TF-dependent coagulation involves the binding of the TFPI-FXa complex to TF-FVIIa via the P1 residue in TFPI (Lys36) and the active site of FVIIa. Unlike the binding of FXa, this requires calcium [22]. Glycosyl phosphatidylinositol (GPI)-anchoring or proteoglycan association of TFPI and membrane binding through the Gla domain of FXa increase the inhibitory potential. The FXa-dependent inhibition of the TF-FVIIa complex by TFPI generates an inactive quarternary complex in the plasma membrane. Internalization of FVIIa results in degradation, yet a small portion of FVIIa is recycled.

Inhibition of TF-FVIIa induced coagulation utilizing recombinant TFPI was analysed in various models of disseminated intravascular coagulation. It reduced mortality and prevented thrombosis in a baboon model [23]. TFPI dose-dependently inhibited coagulation activation during endotoxaemia in humans [24]. In a phase II study the reduction in 28-day all-cause mortality in severe sepsis was observed in the rTFPI group compared with placebo [25]. However, in a randomized controlled study in patients with severe sepsis no effect on all-cause mortality was found [26].

FVIIa inhibitors

  1. Top of page
  2. Abstract
  3. Activation of the coagulation pathway
  4. Tissue factor pathway inhibitor
  5. FVIIa inhibitors
  6. Competing Interests
  7. Acknowledgments
  8. REFERENCES

Active site-inhibited FVIIa (FFR-FVIIa) is a possible therapeutic inhibitor of the TF-FVIIa-dependent initiation of coagulation. FFR-FVIIa is generated from FVIIa by reaction with FFR (D-Phe-L-Phe-L-Arg-chloromethylketone). This tripeptide is covalently incorporated into the active site of FVIIa. FFR-FVIIa competes with endogenous FVIIa for binding to TF and, thereby limits the formation of functional TF-FVIIa complex [27]. The effectiveness of FFR-FVIIa in models of vessel injury, ischaemia/reperfusion injury, venous thrombosis and sepsis to reduce thrombus formation and inflammatory changes has been shown [28–30].

In a dose escalation trial using FFR-FVIIa as an anticoagulant therapy for percutaneous coronary interventions adjunctive heparin was required to prevent vascular thrombosis. At low doses of FFR-FVIIa, vascular thrombosis was observed suggesting that either there was incomplete blockade of the heparin generation pathway, or that the picomolar quantities of thrombin generated independent of the TF-VIIa pathway may be sufficient to cause periprocedural thrombosis although not to prevent access-site bleeding [31].

Because of the lack of natural inhibitors that specifically interfere with FVIIa activity, a number of artificial inhibitors have been developed. Recently, two classes of peptide exosite inhibitors were selected from phage display libraries for their ability to bind to TF-FVIIa. They bind to two distinct exosites on the serine protease domain of FVIIa and exhibit steric and allosteric inhibition [32–34]. Although both peptide classes are potent and selective inhibitors of the TF-FVIIa complex they fail to inhibit 100% activity even at saturating concentrations. This may be overcome by fusion of the two peptides [35] or by using a protease switch with a substrate phage [36].

A variety of synthetic compounds have been designed as active site inhibitors of FVIIa and the TF-FVIIa complex [37–40]. A number of naphthylamidines have recently been reported to have FVIIa inhibitory activity [41]. These compounds were synthesized by coupling amidinobenzaldehyde analogues to a polystyrene resin. Some of these small molecule inhibitors have been tested in vivo and shown to be efficacious in inhibiting thrombus formation and reducing bleeding [40, 42–45]. However, a problem with these compounds may be a non-specific inhibition of other coagulation serine proteases aside from inhibition of FVIIa activity. Moreover, none of the small molecule active site inhibitors of TF-FVIIa has so far shown sufficient oral bioavailability to be considered as an oral anticoagulant.

In search of naturally occurring anticoagulants, two synergistically acting anticoagulant proteins, hemexetin A and B, that inhibit TF-FVIIa as a non-competitive inhibitor of TF FVIIa amidolytic activity were isolated from the venom of the African ringhals cobra [46]. Further studies are required to evaluate their anticoagulant potential in vivo.

TF inhibitors

Two TF residues Lys165 and Lys 166 are critical for substrate interaction of the TF-FVIIa complex. On the basis of this finding a soluble TF mutant (residue 1–219) with alanines substituted for these lysines (TFAA) was developed as an anticoagulant [47]. TFAA binds FVIIa and the resulting complex is unable to activate the substrate FX. Initial experiments in arterial thrombosis models showed antithrombotic activity with reduced bleeding [47, 48]. The potency of TFAA was further increased 20-fold by incorporating amino acid substitutions that increase the affinity for FVIIa [49].

Two different types of anti-TF antibodies have been developed as anti-thrombotic agents. One type interferes with the association of TF with FVIIa [8] and the other interferes only with substrate docking [50]. Although both types are effective in inhibiting TF function it seems that inhibition of substrate binding is more efficient [51]. These antibodies were found to attenuate both the coagulopathy induced by sepsis in baboons [52] and chimpanzees [53] as well as arterial thrombus formation after endatherectomy in chimpanzees [54]. Further work led to a chimeric monoclonal antibody to TF blocking the binding of FX to the TF-FVIIa. In an open-label dose-escalation study of this drug including 26 patients with stable coronary artery disease, no serious adverse events were observed [55].

Exogenous inhibitors of substrate binding on the TF-FVIIa complex have been isolated from hookworms. Nematode anticoagulant protein c2 (rNAPc2) is an 85-amino-acid serine protease inhibitor isolated from canine hookworms that directly inhibits the catalytic complex of TF-FVIIa by first binding to FXa. In contrast to TFPI NAPc2 binds at an exosite of FX/FXa at the active site of FXa. The anticoagulant effect of NAPc2 was investigated in an open-label sequential dose ranging study in patients undergoing orthopaedic surgery. The efficacy and safety profile was comparable with the prophylactic use of low molecular weight heparins [56]. Moreover, in patients undergoing coronary angioplasty NAPc2, in combination with unfractionated heparin, was found to be safe and effective in inhibiting thrombin generation [57]. In addition to inhibiton of coagulation anti-TF antibodies and NAPc2 may reduce tumour growth and metastasis by interfering with signalling pathways [58, 59].

Various strategies have been used to generate inhibitors of the initiation pathway of blood coagulation. Several types of inhibitors of TF, FVII/FVIIa or the TF/FVIIa complex have been developed and evaluated on these targets as anticoagulants in vitro and in vivo. A number of studies have raised the possibility of improved mode of anticoagulation, yet further experimental and clinical studies are required before the promise inherent in these novel approaches can be fully evaluated.

REFERENCES

  1. Top of page
  2. Abstract
  3. Activation of the coagulation pathway
  4. Tissue factor pathway inhibitor
  5. FVIIa inhibitors
  6. Competing Interests
  7. Acknowledgments
  8. REFERENCES
  • 1
    Mann KG. Thrombin formation. Chest 2003; 124: 4S10S.
  • 2
    Giesen PL, Rauch U, Bohrmann B, Kling D, Roque M, Fallon JT, Badimon JJ, Himber J, Riederer MA, Nemerson Y. Blood-borne tissue factor: another view of thrombosis. Proc Natl Acad Sci U S A 1999; 96: 23115.
  • 3
    Del Conde I, Shrimpton CN, Thiagarajan P, Lopez JA. Tissue-factor-bearing microvesicles arise from lipid rafts and fuse with activated platelets to initiate coagulation. Blood 2005; 106: 160411.
  • 4
    Panes O, Matus V, Saez CG, Quiroga T, Pereira J, Mezzano D. Human platelets synthesize and express functional tissue factor. Blood 2007; 109: 524250.
  • 5
    Schwertz H, Tolley ND, Foulks JM, Denis MM, Risenmay BW, Buerke M, Tilley RE, Rondina MT, Harris EM, Kraiss LW, Mackman N, Zimmerman GA, Weyrich AS. Signal-dependent splicing of tissue factor pre-mRNA modulates the thrombogenicity of human platelets. J Exp Med 2006; 203: 243340.
  • 6
    Shaw AW, Pureza VS, Sligar SG, Morrissey JH. The local phospholipid environment modulates the activation of blood clotting. J Biol Chem 2007; 282: 655663.
  • 7
    Monroe DM, Hoffman M. Coagulation factor interaction with platelets. Thromb Haemost 2002; 88: 179.
  • 8
    Himber J, Kirchhofer D, Riederer M, Tschopp TB, Steiner B, Roux SP. Dissociation of antithrombotic effect and bleeding time prolongation in rabbits by inhibiting tissue factor function. Thromb Haemost 1997; 78: 11429.
  • 9
    Taubman MB, Fallon JT, Schecter AD, Giesen P, Mendlowitz M, Fyfe BS, Marmur JD, Nemerson Y. Tissue factor in the pathogenesis of atherosclerosis. Thromb Haemost 1997; 78: 2004.
  • 10
    Kaikita K, Ogawa H, Yasue H, Takeya M, Takahashi K, Saito T, Hayasaki K, Horiuchi K, Takizawa A, Kamikubo Y, Nakamura S. Tissue factor expression on macrophages in coronary plaques in patients with unstable angina. Arterioscler Thromb Vasc Biol 1997; 17: 22327.
  • 11
    Badimon JJ, Lettino M, Toschi V, Fuster V, Berrozpe M, Chesebro JH, Badimon L. Local inhibition of tissue factor reduces the thrombogenicity of disrupted human atherosclerotic plaques: effects of tissue factor pathway inhibitor on plaque thrombogenicity under flow conditions. Circulation 1999; 99: 17807.
  • 12
    Marmur JD, Sharma SK, Weinrauch M, Kantrowitz N, Dangas G, Kokinakkis S, Ambrose JA. Thrombin generation and activity during coronary angioplasty: influence of angiographic lesion morphology. J Invasive Cardiol 1997; 9: 4106.
  • 13
    Jude B, Agraou B, McFadden EP, Susen S, Bauters C, Lepelley P, Vanhaesbroucke C, Devos P, Cosson A, Asseman P. Evidence for time-dependent activation of monocytes in the systemic circulation in unstable angina but not in acute myocardial infarction or in stable angina. Circulation 1994; 90: 16628.
  • 14
    Ott I, Neumann FJ, Kenngott S, Gawaz M, Schomig A. Procoagulant inflammatory responses of monocytes after direct balloon angioplasty in acute myocardial infarction. Am J Cardiol 1998; 82: 93842.
  • 15
    Steppich B, Mattisek C, Sobczyk D, Kastrati A, Schomig A, Ott I. Tissue factor pathway inhibitor on circulating microparticles in acute myocardial infarction. Thromb Haemost 2005; 93: 359.
  • 16
    Erlich JH, Boyle EM, Labriola J, Kovacich JC, Santucci RA, Fearns C, Morgan EN, Yun W, Luther T, Kojikawa O, Martin TR, Pohlman TH, Verrier ED, Mackman N. Inhibition of the tissue factor-thrombin pathway limits infarct size after myocardial ischemia-reperfusion injury by reducing inflammation. Am J Pathol 2000; 157: 184962.
  • 17
    Asada Y, Hara S, Tsuneyoshi A, Hatakeyama K, Kisanuki A, Marutsuka K, Sato Y, Kamikubo Y, Sumiyoshi A. Fibrin-rich and platelet-rich thrombus formation on neointima: recombinant tissue factor pathway inhibitor prevents fibrin formation and neointimal development following repeated balloon injury of rabbit aorta. Thromb Haemost 1998; 80: 50611.
  • 18
    Himber J, Wohlgensinger C, Roux S, Damico LA, Fallon JT, Kirchhofer D, Nemerson Y, Riederer MA. Inhibition of tissue factor limits the growth of venous thrombus in the rabbit. J Thromb Haemost 2003; 1: 88995.
  • 19
    Taylor FB Jr, Chang A, Ruf W, Morrissey JH, Hinshaw L, Catlett R, Blick K, Edgington TS. Lethal E. coli septic shock is prevented by blocking tissue factor with monoclonal antibody. Circ Shock 1991; 33: 12734.
  • 20
    Ruf W, Yokota N, Schaffner F. Tissue factor in cancer progression and angiogenesis. Thromb Res 2010; 125 (Suppl. 2): S368.
  • 21
    Ott I, Weigand B, Michl R, Seitz I, Sabbari-Erfani N, Neumann FJ, Schomig A. Tissue factor cytoplasmic domain stimulates migration by activation of the GTPase Rac1 and the mitogen-activated protein kinase p38. Circulation 2005; 111: 34955.
  • 22
    Broze GJ Jr. The rediscovery and isolation of TFPI. J Thromb Haemost 2003; 1: 16715.
  • 23
    Hedner U, Erhardtsen E. Future possibilities in the regulation of the extrinsic pathway: rFVIIa and TFPI. Ann Med 2000; 32 (Suppl. 1): 6872.
  • 24
    de Jonge E, Dekkers PE, Creasey AA, Hack CE, Paulson SK, Karim A, Kesecioglu J, Levi M, van Deventer SJ, van Der Poll T. Tissue factor pathway inhibitor dose-dependently inhibits coagulation activation without influencing the fibrinolytic and cytokine response during human endotoxemia. Blood 2000; 95: 11249.
  • 25
    Abraham E, Reinhart K, Svoboda P, Seibert A, Olthoff D, Dal Nogare A, Postier R, Hempelmann G, Butler T, Martin E, Zwingelstein C, Percell S, Shu V, Leighton A, Creasey AA. Assessment of the safety of recombinant tissue factor pathway inhibitor in patients with severe sepsis: a multicenter, randomized, placebo-controlled, single-blind, dose escalation study. Crit Care Med 2001; 29: 20819.
  • 26
    Abraham E, Reinhart K, Opal S, Demeyer I, Doig C, Rodriguez AL, Beale R, Svoboda P, Laterre PF, Simon S, Light B, Spapen H, Stone J, Seibert A, Peckelsen C, De Deyne C, Postier R, Pettila V, Artigas A, Percell SR, Shu V, Zwingelstein C, Tobias J, Poole L, Stolzenbach JC, Creasey AA. Efficacy and safety of tifacogin (recombinant tissue factor pathway inhibitor) in severe sepsis: a randomized controlled trial. JAMA 2003; 290: 23847.
  • 27
    Rao LV, Ezban M. Active site-blocked activated factor VII as an effective antithrombotic agent: mechanism of action. Blood Coagul Fibrinolysis 2000; 11 (Suppl. 1): S135143.
  • 28
    Harker LA, Hanson SR, Wilcox JN, Kelly AB. Antithrombotic and antilesion benefits without hemorrhagic risks by inhibiting tissue factor pathway. Haemostasis 1996; 26 (Suppl. 1): 7682.
  • 29
    Golino P, Ragni M, Cirillo P, D’Andrea D, Scognamiglio A, Ravera A, Buono C, Ezban M, Corcione N, Vigorito F, Condorelli M, Chiariello M. Antithrombotic effects of recombinant human, active site-blocked factor VIIa in a rabbit model of recurrent arterial thrombosis. Circ Res 1998; 82: 3946.
  • 30
    Lev EI, Marmur JD, Zdravkovic M, Osende JI, Robbins J, Delfin JA, Richard M, Erhardtsen E, Thomsen MS, Lincoff AM, Badimon JJ. Antithrombotic effect of tissue factor inhibition by inactivated factor VIIa: an ex vivo human study. Arterioscler Thromb Vasc Biol 2002; 22: 103641.
  • 31
    Lincoff A. First clinical investigation of a tissue-factor inhibitor administered during percutaneous coronary revascularization: a randomized, double-blinded, dose-escalation trial – assessing safety and efficacy of FFR-FVIIa in percutaneous transluminal coronary angioplasty (ASIS) trial. J Am Coll Cardiol 2000; 36: 31025.
  • 32
    Dennis MS, Eigenbrot C, Skelton NJ, Ultsch MH, Santell L, Dwyer MA, O’Connell MP, Lazarus RA. Peptide exosite inhibitors of factor VIIa as anticoagulants. Nature 2000; 404: 46570.
  • 33
    Dennis MS, Roberge M, Quan C, Lazarus RA. Selection and characterization of a new class of peptide exosite inhibitors of coagulation factor VIIa. Biochemistry 2001; 40: 951321.
  • 34
    Roberge M, Santell L, Dennis MS, Eigenbrot C, Dwyer MA, Lazarus RA. A novel exosite on coagulation factor VIIa and its molecular interactions with a new class of peptide inhibitors. Biochemistry 2001; 40: 952231.
  • 35
    Roberge M, Peek M, Kirchhofer D, Dennis MS, Lazarus RA. Fusion of two distinct peptide exosite inhibitors of Factor VIIa. Biochem J 2002; 363: 38793.
  • 36
    Maun HR, Eigenbrot C, Lazarus RA. Engineering exosite peptides for complete inhibition of factor VIIa using a protease switch with substrate phage. J Biol Chem 2003; 278: 2182330.
  • 37
    Sorensen BB, Persson E, Freskgard PO, Kjalke M, Ezban M, Williams T, Rao LV. Incorporation of an active site inhibitor in factor VIIa alters the affinity for tissue factor. J Biol Chem 1997; 272: 118638.
  • 38
    Uchiba M, Okajima K, Abe H, Okabe H, Takatsuki K. Effect of nafamostat mesilate, a synthetic protease inhibitor, on tissue factor-factor VIIa complex activity. Thromb Res 1994; 74: 15561.
  • 39
    Lazarus RA, Olivero AG, Eigenbrot C, Kirchhofer D. Inhibitors of tissue factor. Factor VIIa for anticoagulant therapy. Curr Med Chem 2004; 11: 227590.
  • 40
    Olivero AG, Eigenbrot C, Goldsmith R, Robarge K, Artis DR, Flygare J, Rawson T, Sutherlin DP, Kadkhodayan S, Beresini M, Elliott LO, DeGuzman GG, Banner DW, Ultsch M, Marzec U, Hanson SR, Refino C, Bunting S, Kirchhofer D. A selective, slow binding inhibitor of factor VIIa binds to a nonstandard active site conformation and attenuates thrombus formation in vivo. J Biol Chem 2005; 280: 91609.
  • 41
    Buckman BO, Chou YL, McCarrick M, Liang A, Lentz D, Mohan R, Morrissey MM, Shaw KJ, Trinh L, Light DR. Solid-phase synthesis of naphthylamidines as factor VIIa/tissue factor inhibitors. Bioorg Med Chem Lett 2005; 15: 224952.
  • 42
    Suleymanov OD, Szalony JA, Salyers AK, LaChance RM, Parlow JJ, South MS, Wood RS, Nicholson NS. Pharmacological interruption of acute thrombus formation with minimal hemorrhagic complications by a small molecule tissue factor/factor VIIa inhibitor: comparison to factor Xa and thrombin inhibition in a nonhuman primate thrombosis model. J Pharmacol Exp Ther 2003; 306: 111521.
  • 43
    Szalony JA, Suleymanov OD, Salyers AK, Panzer-Knodle SG, Blom JD, LaChance RM, Case BL, Parlow JJ, South MS, Wood RS, Nicholson NS. Administration of a small molecule tissue factor/factor VIIa inhibitor in a non-human primate thrombosis model of venous thrombosis: effects on thrombus formation and bleeding time. Thromb Res 2003; 112: 16774.
  • 44
    Young WB, Mordenti J, Torkelson S, Shrader WD, Kolesnikov A, Rai R, Liu L, Hu H, Leahy EM, Green MJ, Sprengeler PA, Katz BA, Yu C, Janc JW, Elrod KC, Marzec UM, Hanson SR. Factor VIIa inhibitors: chemical optimization, preclinical pharmacokinetics, pharmacodynamics, and efficacy in an arterial baboon thrombosis model. Bioorg Med Chem Lett 2006; 16: 203741.
  • 45
    Arnold CS, Parker C, Upshaw R, Prydz H, Chand P, Kotian P, Bantia S, Babu YS. The antithrombotic and anti-inflammatory effects of BCX-3607, a small molecule tissue factor/factor VIIa inhibitor. Thromb Res 2006; 117: 3439.
  • 46
    Banerjee Y, Mizuguchi J, Iwanaga S, Kini RM. Hemextin AB complex – a snake venom anticoagulant protein complex that inhibits factor VIIa activity. Pathophysiol Haemost Thromb 2005; 34: 1847.
  • 47
    Kelley RF, Refino CJ, O'Connell MP, Modi N, Sehl P, Lowe D, Pater C, Bunting S. A soluble tissue factor mutant is a selective anticoagulant and antithrombotic agent. Blood 1997; 89: 321927.
  • 48
    Himber J, Refino CJ, Burcklen L, Roux S, Kirchhofer D. Inhibition of arterial thrombosis by a soluble tissue factor mutant and active site-blocked factors IXa and Xa in the guinea pig. Thromb Haemost 2001; 85: 47581.
  • 49
    Yang J, Lee GF, Riederer MA, Kelley RF. Enhancing the anticoagulant potency of soluble tissue factor mutants by increasing their affinity to factor VIIa. Thromb Haemost 2002; 87: 4508.
  • 50
    Kirchhofer D, Moran P, Chiang N, Kim J, Riederer MA, Eigenbrot C, Kelley RF. Epitope location on tissue factor determines the anticoagulant potency of monoclonal anti-tissue factor antibodies. Thromb Haemost 2000; 84: 107281.
  • 51
    Levi M, ten Cate H, Bauer KA, van der Poll T, Edgington TS, Buller HR, van Deventer SJ, Hack CE, ten Cate JW, Rosenberg RD. Inhibition of endotoxin-induced activation of coagulation and fibrinolysis by pentoxifylline or by a monoclonal anti-tissue factor antibody in chimpanzees. J Clin Invest 1994; 93: 11420.
  • 52
    Huang H, Norledge BV, Liu C, Olson AJ, Edgington TS. Selective attenuation of the extrinsic limb of the tissue factor-driven coagulation protease cascade by occupancy of a novel peptidyl docking site on tissue factor. Biochemistry 2003; 42: 1061926.
  • 53
    Biemond BJ, Levi M, ten Cate H, Soule HR, Morris LD, Foster DL, Bogowitz CA, van der Poll T, Buller HR, ten Cate JW. Complete inhibition of endotoxin-induced coagulation activation in chimpanzees with a monoclonal Fab fragment against factor VII/VIIa. Thromb Haemost 1995; 73: 22330.
  • 54
    Jiao JA, Kelly AB, Marzec UM, Nieves E, Acevedo J, Burkhardt M, Edwards A, Zhu XY, Chavaillaz PA, Wong A, Wong JL, Egan JO, Taylor D, Rhode PR, Wong HC. Inhibition of acute vascular thrombosis in chimpanzees by an anti-human tissue factor antibody targeting the factor X binding site. Thromb Haemost 2010; 103: 22433.
  • 55
    Morrow DA, Murphy SA, McCabe CH, Mackman N, Wong HC, Antman EM. Potent inhibition of thrombin with a monoclonal antibody against tissue factor (Sunol-cH36): results of the PROXIMATE-TIMI 27 trial. Eur Heart J 2005; 26: 6828.
  • 56
    Lee A, Agnelli G, Buller H, Ginsberg J, Heit J, Rote W, Vlasuk G, Costantini L, Julian J, Comp P, van Der Meer J, Piovella F, Raskob G, Gent M. Dose-response study of recombinant factor VIIa/tissue factor inhibitor recombinant nematode anticoagulant protein c2 in prevention of postoperative venous thromboembolism in patients undergoing total knee replacement. Circulation 2001; 104: 748.
  • 57
    Moons AH, Peters RJ, Bijsterveld NR, Piek JJ, Prins MH, Vlasuk GP, Rote WE, Buller HR. Recombinant nematode anticoagulant protein c2, an inhibitor of the tissue factor/factor VIIa complex, in patients undergoing elective coronary angioplasty. J Am Coll Cardiol 2003; 41: 214753.
  • 58
    Mueller BM, Reisfeld RA, Edgington TS, Ruf W. Expression of tissue factor by melanoma cells promotes efficient hematogenous metastasis. Proc Natl Acad Sci U S A 1992; 89: 118326.
  • 59
    Hembrough TA, Swartz GM, Papathanassiu A, Vlasuk GP, Rote WE, Green SJ, Pribluda VS. Tissue factor/factor VIIa inhibitors block angiogenesis and tumor growth through a nonhemostatic mechanism. Cancer Res 2003; 63: 29973000.