A monoclonal antibody against rabbit tissue factor inhibits thrombus formation in stenotic injured rabbit carotid arteries.

Abstract Background: Factor XI (FXI) inhibition demonstrated strong efficacy in preventing thrombus formation in preclinical and clinical models of arterial and venous thrombosis. However, the effect of FXI inhibition in halting the progression of a formed clot remains largely unknown. Aims: This study aims to test whether abelacimab, a dual-acting FXI and activated FXI (FXIa) monoclonal antibody, is effective in halting clot formation and downstream growth when administered before or during active clot formation in an established baboon femoral arterio-venous (AV) shunt model. Methods: Three baboons had a chronic femoral AV shunt put in place; platelet and fibrin deposition inside and distal to collagen- or collagen + tissue factor (TF)-coated vascular grafts were measured at baseline (control), in a therapeutic setting, where abelacimab (1 mg/kg, intravenously) was administered 30 minutes after thrombus initiation, and in a preventative setting within the first 48 h and 1 week (144 - 216 h) post-administration. Pharmacodynamic effect was measured by activated partial thromboplastin time (aPTT). Results: Consistent with its half-life of 20 to 30 days, single iv administration of abelacimab at a dose of 1 mg/kg resulted in long-lasting (> 4-week) aPTT prolongation (> 2-fold). Administration of abelacimab 30 minutes after initiation of thrombosis using grafts coated either with collagen or with collagen + TF quickly halted downstream propagation of platelet and fibrin deposition compared to control. Further, downstream propagation of platelet and fibrin deposition was markedly reduced when clotting was induced by collagen, or collagen + tissue factor after abelacimab administration. Conclusions: These data suggest that abelacimab, a dual-acting anti-FXI/FXIa monoclonal antibody with a single long-lasting iv injection has the potential to slow down the growth and reduce the size of thrombi when admistered before or after clot induction. Data indicate a potential for therapeutic benefit of targeting FXI both in therapeutic and preventive settings. Sponsored by: Anthos Therapeutics Inc., 55 Cambridge Parkway, Suite 103, Cambridge, MA 02142 Figure 1 Figure 1. Disclosures Wallisch: Aronora Inc,: Current Employment. Khder: Anthos Therapeutics: Consultancy; Novartis: Current equity holder in publicly-traded company, Other: Retiree. Bloomfield: Anthos Therapeutics: Current Employment. Gruber: Aronora Inc.: Current Employment, Current equity holder in publicly-traded company; Oregon Health and Science University: Current Employment.

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Expression of exogenous tissue factor pathway inhibitor in vivo suppresses thrombus formation in injured rabbit carotid arteries

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(01)01350-x ◽

2001 ◽

Vol 38 (2) ◽

pp. 569-576 ◽

Cited By ~ 24

Author(s):

Paolo Golino ◽

Plinio Cirillo ◽

Paolo Calabro’ ◽

Massimo Ragni ◽

Enrico V Avvedimento ◽

...

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Carotid Arteries ◽

Thrombus Formation ◽

Tissue Factor Pathway

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Dietary α-Linolenic Acid Inhibits Arterial Thrombus Formation, Tissue Factor Expression, and Platelet Activation

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.111.226118 ◽

2011 ◽

Vol 31 (8) ◽

pp. 1772-1780 ◽

Cited By ~ 45

Author(s):

Erik W. Holy ◽

Marc Forestier ◽

Eva K. Richter ◽

Alexander Akhmedov ◽

Florian Leiber ◽

...

Keyword(s):

Tissue Factor ◽

Linolenic Acid ◽

Platelet Activation ◽

Thrombus Formation ◽

Tissue Factor Expression ◽

Arterial Thrombus ◽

Factor Expression

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Local delivery of soluble platelet collagen receptor glycoprotein VI inhibits thrombus formation in vivo

Thrombosis and Haemostasis ◽

10.1160/th05-11-0731 ◽

2006 ◽

Vol 95 (05) ◽

pp. 763-766 ◽

Cited By ~ 31

Author(s):

Andreas Bültmann ◽

Christian Herdeg ◽

Zhongmin Li ◽

Götz Münch ◽

Christine Baumgartner ◽

...

Keyword(s):

Carotid Artery ◽

Vascular Injury ◽

Carotid Arteries ◽

Thrombus Formation ◽

Critical Role ◽

Local Delivery ◽

Computer Assisted ◽

Glycoprotein Vi ◽

Collagen Receptor

SummaryPlatelet-mediated thrombus formation at the site of vascular injury isa major trigger for thrombo-ischemic complications after coronary interventions. The platelet collagen receptor glycoprotein VI (GPVI) plays a critical role in the initiation of arterial thrombus formation. Endothelial denudation of the right carotid artery in rabbits was induced through balloon injury. Subsequently, local delivery of soluble, dimeric fusion protein of GPVI (GPVI-Fc) (n=7) or control Fc (n=7) at the site of vascular injury was performed with a modified double-balloon drugdelivery catheter.Thrombus area within the injured carotid artery was quantified using a computer-assisted image analysis and was used as index of thrombus formation.The extent of thrombus formation was significantly reduced in GPVI-Fc- compared with control Fc-treated carotid arteries (relative thrombus area, GPVI-Fc vs. Fc: 9.3 ± 4.2 vs. 2.3 ± 1.7, p<0.001). Local delivery of soluble GPVI resulted in reduced thrombus formation after catheter-induced vascular injury.These data suggest a selective pharmacological modulation of GPVI-collagen interactions to be important for controlling onset and progression of pathological arterial thrombosis, predominantly or even exclusively at sites of injured carotid arteries in the absence of systemic platelet therapy.

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Increased tissue factor expression on circulating monocytes in chronic HIV infection: relationship to in vivo coagulation and immune activation

Blood ◽

10.1182/blood-2009-03-210179 ◽

2010 ◽

Vol 115 (2) ◽

pp. 161-167 ◽

Cited By ~ 166

Author(s):

Nicholas T. Funderburg ◽

Elizabeth Mayne ◽

Scott F. Sieg ◽

Robert Asaad ◽

Wei Jiang ◽

...

Keyword(s):

Hiv Infection ◽

Tissue Factor ◽

Immune Activation ◽

Interleukin 6 ◽

Plasma Levels ◽

Thrombus Formation ◽

Hiv Replication ◽

Increased Risk

Abstract HIV infection is associated with an increased risk of thrombosis; and as antiretroviral therapy has increased the lifespan of HIV-infected patients, their risk for cardiovascular events is expected to increase. A large clinical study found recently that all-cause mortality for HIV+ patients was related to plasma levels of interleukin-6 and to D-dimer products of fibrinolysis. We provide evidence that this elevated risk for coagulation may be related to increased proportions of monocytes expressing cell surface tissue factor (TF, thromboplastin) in persons with HIV infection. Monocyte TF expression could be induced in vitro by lipopolysaccharide and flagellin, but not by interleukin-6. Monocyte expression of TF was correlated with HIV levels in plasma, with indices of immune activation, and with plasma levels of soluble CD14, a marker of in vivo lipopolysaccharide exposure. TF levels also correlated with plasma levels of D-dimers, reflective of in vivo clot formation and fibrinolysis. Thus, drivers of immune activation in HIV disease, such as HIV replication, and potentially, microbial translocation, may activate clotting cascades and contribute to thrombus formation and cardiovascular morbidities in HIV infection.

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Antithrombotic effect of a monoclonal antibody to the platelet glycoprotein IIb/IIIa receptor in an experimental animal model

Blood ◽

10.1182/blood.v68.3.783.bloodjournal683783 ◽

1986 ◽

Vol 68 (3) ◽

pp. 783-786 ◽

Cited By ~ 1

Author(s):

BS Coller ◽

JD Folts ◽

LE Scudder ◽

SR Smith

Keyword(s):

Monoclonal Antibody ◽

Animal Model ◽

Platelet Aggregation ◽

Ex Vivo ◽

Thrombus Formation ◽

Platelet Glycoprotein ◽

Antithrombotic Effect ◽

Antithrombotic Agent ◽

Antithrombotic Effects ◽

Platelet Thrombus

A murine monoclonal antibody directed at the platelet glycoprotein IIb/IIIa complex, which blocks platelet aggregation ex vivo, was tested for its antithrombotic effects in an established animal model of acute platelet thrombus formation in partially stenosed arteries. Infusion of 0.7 to 0.8 mg/kg of the F(ab')2 fragment of the antibody completely blocked new thrombus formation despite multiple provocations, making it the most potent antithrombotic agent tested in this model.

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Accumulation of Tissue Factor into Developing Thrombi In Vivo Is Dependent upon Microparticle P-Selectin Glycoprotein Ligand 1 and Platelet P-Selectin

Journal of Experimental Medicine ◽

10.1084/jem.20021868 ◽

2003 ◽

Vol 197 (11) ◽

pp. 1585-1598 ◽

Cited By ~ 501

Author(s):

Shahrokh Falati ◽

Qingde Liu ◽

Peter Gross ◽

Glenn Merrill-Skoloff ◽

Janet Chou ◽

...

Keyword(s):

Tissue Factor ◽

Blood Coagulation ◽

Thrombus Formation ◽

Recipient Mouse ◽

Wild Type ◽

Activated Platelets ◽

Injury Model ◽

Platelet Thrombus ◽

Flowing Blood

Using a laser-induced endothelial injury model, we examined thrombus formation in the microcirculation of wild-type and genetically altered mice by real-time in vivo microscopy to analyze this complex physiologic process in a system that includes the vessel wall, the presence of flowing blood, and the absence of anticoagulants. We observe P-selectin expression, tissue factor accumulation, and fibrin generation after platelet localization in the developing thrombus in arterioles of wild-type mice. However, mice lacking P-selectin glycoprotein ligand 1 (PSGL-1) or P-selectin, or wild-type mice infused with blocking P-selectin antibodies, developed platelet thrombi containing minimal tissue factor and fibrin. To explore the delivery of tissue factor into a developing thrombus, we identified monocyte-derived microparticles in human platelet–poor plasma that express tissue factor, PSGL-1, and CD14. Fluorescently labeled mouse microparticles infused into a recipient mouse localized within the developing thrombus, indicating that one pathway for the initiation of blood coagulation in vivo involves the accumulation of tissue factor– and PSGL-1–containing microparticles in the platelet thrombus expressing P-selectin. These monocyte-derived microparticles bind to activated platelets in an interaction mediated by platelet P-selectin and microparticle PSGL-1. We propose that PSGL-1 plays a role in blood coagulation in addition to its known role in leukocyte trafficking.

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Platelets, circulating tissue factor, and fibrin colocalize in ex vivo thrombi: real-time fluorescence images of thrombus formation and propagation under defined flow conditions

Blood ◽

10.1182/blood-2002-03-0902 ◽

2002 ◽

Vol 100 (8) ◽

pp. 2787-2792 ◽

Cited By ~ 95

Author(s):

Viji Balasubramanian ◽

Eric Grabowski ◽

Alessandra Bini ◽

Yale Nemerson

Keyword(s):

Real Time ◽

Tissue Factor ◽

Ex Vivo ◽

Thrombus Formation ◽

High Sensitivity ◽

Flow Chamber ◽

Flow Conditions ◽

Coated Glass ◽

Relative Contribution ◽

Fluorescent Markers

Although it is generally accepted that the initial event in coagulation and intravascular thrombus formation is the exposure of tissue factor (TF) to blood, there is still little agreement about the mechanisms of thrombus propagation and the identities of the molecular species participating in this process. In this study, we characterized the thrombotic process in real-time and under defined flow conditions to determine the relative contribution and spatial distribution of 3 components of the thrombi: circulating or blood-borne TF (cTF), fibrin, and platelets. For this purpose, we used high-sensitivity, multicolor immunofluorescence microscopy coupled with a laminar flow chamber. Freshly drawn blood, labeled with mepacrine (marker for platelets and white cells), anti-hTF1Alexa.568 (marker for tissue factor), and anti-T2G1Cy5 (marker for fibrin) was perfused over collagen-coated glass slides at wall shear rates of 100 and 650 s−1. A motorized filter cube selector facilitated imaging every 5 seconds at 1 of 3 different wavelengths, corresponding to optimal wavelengths for the 3 markers above. Real-time video recordings obtained during each of 10 discrete experiments show rapid deposition of platelets and fibrin onto collagen-coated glass. Overlay images of fluorescent markers corresponding to platelets, fibrin, and cTF clearly demonstrate colocalization of these 3 components in growing thrombi. These data further support our earlier observations that, in addition to TF present in the vessel wall, there is a pool of TF in circulating blood that contributes to the propagation of thrombosis at a site of vascular injury.

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Abstract 14366: T-lymphocytes May Contribute to Thrombus Formation in Patients With Acute Coronary Syndrome via Expression of Tissue Factor

Circulation ◽

10.1161/circ.132.suppl_3.14366 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Giovanni Cimmino ◽

Giovanni Ciccarelli ◽

Stefano Conte ◽

Grazia Pellegrino ◽

Luigi Insabato ◽

...

Keyword(s):

T Cells ◽

T Lymphocytes ◽

Tissue Factor ◽

Thrombus Formation ◽

Specific Antigen ◽

Activated T Cells ◽

Coronary Syndrome ◽

Stable Cad

Background: Activation of T-cells plays an important role in the pathophysiology of acute coronary syndromes (ACS). We have previously shown that plaques from ACS patients are characterized by a selective oligoclonal expansion of T-cells, indicating a specific, antigen-mediated recruitment of T-cells within the unstable lesions. We have also previously reported that activated T-cells in vitro express functional Tissue Factor (TF) on their surface. At the moment, however it is not known whether expression of TF by T-cells may contribute to thrombus formation in vivo. Methods: Blood was collected from the aorta and the coronary sinus of 13 NSTEMI and 10 stable CAD patients. CD3+ cells were selectively isolated and TF gene expression (real time PCR)and protein levels (western blot) were evaluated. In additional 7 STEMI patients, thrombotic formation material was obtained from the occluded coronary artery by catheter aspiration during primary PCI. TF expression in CD3+ cells was evaluated by immunohistochemistry and confocal microscopy. Results: Transcardiac TF expression in CD3+ cells was significantly higher in NSTEMI patients as compared to CD3+ cells obtained from stable CAD patients. Interestingly, thrombi aspirated from STEMI patients resulted enriched in CD3+cells, which expressed TF on their surface as shown in the figure. Conclusions: Our data demonstrate that in patients with ACS, T-lymphocytes may express surface TF, thus contributing to the process of thrombus formation. This finding may shed new light into the pathophysiologyof ACS.

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Long-term inhibition of nitric oxide synthesis increases arterial thrombogenecity in rat carotid artery

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00739.2001 ◽

2002 ◽

Vol 282 (4) ◽

pp. H1478-H1484 ◽

Cited By ~ 16

Author(s):

Mayuko Kubo-Inoue ◽

Kensuke Egashira ◽

Makoto Usui ◽

Masao Takemoto ◽

Kisho Ohtani ◽

...

Keyword(s):

Nitric Oxide ◽

Carotid Artery ◽

Tissue Factor ◽

Ace Inhibitor ◽

Vascular Tissue ◽

Thrombus Formation ◽

Coronary Syndrome ◽

Ace Activity ◽

Reliable Marker

Reduced activity of endothelial nitric oxide (NO) may be involved in thrombus formation on atherosclerotic plaques, a major cause of acute coronary syndrome. However, mechanisms of such increase in arterial thrombogenecity have not been fully understood. We previously reported that long-term inhibition of NO synthesis by administration of N G-nitro-l-arginine methyl ester (l-NAME) causes hypertension and activates vascular tissue angiotensin-converting enzyme (ACE) activity. We used this model to investigate the mechanism by which long-term impairment of NO activity increases arterial thrombogenecity. We observed cyclic flow variations (CFVs), a reliable marker of platelet thrombi, after the production of stenosis of the carotid artery in rats treated with l-NAME for 4 wk. The thrombin antagonist argatroban suppressed the CFVs. The CFVs were detected in rats receiving l-NAME plus hydralazine but not in rats receiving l-NAME plus an ACE inhibitor (imidapril). Treatment with the ACE inhibitor imidapril, but not with hydralazine, prevented l-NAME-induced increases in carotid arterial ACE activity and attenuated tissue factor expression. These results suggest that long-term inhibition of endothelial NO synthesis may increase arterial thrombogenecity at least in part through angiotensin II-induced induction of tissue factor and the resultant thrombin generation. These data provide a new insight as to how endothelial NO exhibits antithrombogenic properties of the endothelium.

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