Factor VIIa-antithrombin complexes in patients with arterial and venous thrombosis

SummaryAntithrombin (AT), in the presence of heparin, is able to inhibit the catalytic activity of factor VIIa bound to tissue factor (TF) on cell surfaces. The clinical meaning of FVIIa-AT complexes plasma levels is unknown. It was the objective of this study to evaluate FVIIa-AT complexes in subjects with thrombosis. Factor VIIa-AT complexes plasma levels in 154 patients consecutively referred to our Department with arterial or venous thrombosis and in a group of 154 healthy subjects, were measured. Moreover, FVIIa-AT complexes were determined in: i) n = 53 subjects belonging to 10 families with inherited factor VII deficiency; ii) n = 58 subjects belonging to seven families with AT deficiency; iii) n = 49 patients undergoing oral anticoagulant therapy (OAT). Factor VIIaAT levels were determined by a specific ELISA kit (R&D, Diagnostica Stago, Gennevilliers, France). Factor VIIa-AT complexes mean plasma levels were lower in patients with either acute arterial (136 ± 40 pM) or venous (142 ± 53 pM) thrombosis than subjects with previous thrombosis (arterial 164 ± 33 pM and venous 172 ± 61 pM, respectively) and than healthy controls (156 ± 63 pM). Differences between acute and previous thrombosis, were statistically significant (p < 0.05). Subjects with inherited and acquired (under OAT) factor VII deficiency had statistically significant lower FVIIa-AT complexes plasma levels (80 ± 23 pM and 55 ± 22 pM, respectively) than controls (150 ± 51 pM, p < 0.0001 and 156 ± 63 pM, p < 0.00001, respectively). Factor VIIa-AT complexes are positively correlated with plasma factor VII/VIIa levels. Further investigations are needed to verify the possible role of higher FVIIa-AT complex plasma levels in predicting hypercoagulable states and thrombosis.

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Factor VIIa-antithrombin complex: a possible new biomarker for activated coagulation

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2016-0399 ◽

2017 ◽

Vol 55 (4) ◽

Cited By ~ 4

Author(s):

Luca Spiezia ◽

Elena Campello ◽

Fabio Dalla Valle ◽

Barry Woodhams ◽

Paolo Simioni

Keyword(s):

Clinical Studies ◽

Plasma Levels ◽

Factor Viia ◽

Transmembrane Protein ◽

Thrombotic Event ◽

Factor Ix ◽

Factor Vii ◽

Circulating Levels ◽

Coagulation Pathway

AbstractThe activation of the extrinsic coagulation pathway occurs after endothelial injury when the tissue factor (TF), a transmembrane protein located outside the vasculature, binds factor VII (FVII) or activated FVII (FVIIa). Once formed, the TF-VIIa complex activates both factor IX and X and initiates the coagulation process. The TF-VIIa complex is inhibited by both TF pathway inhibitor (TFPI) and antithrombin (AT). The interaction between TF-VIIa and AT induces FVIIa-AT complex formation, which is released into the plasma. Because AT reacts with FVIIa only when it is bound to TF, the circulating levels of FVIIa-AT reflect the degree of exposure of TF to blood. Preliminary clinical studies have shown higher plasma levels of FVIIa-AT complex both in patients with a prior arterial or venous thrombotic event. Increased plasma levels of FVIIa-AT have also been reported in a number of other prothrombotic conditions – antiphospholipid antibodies, solid and hematological malignancies, pre-eclampsia (PE), obesity and cardiac surgery. However, most of the studies published so far are retrospective and with a limited sample size. Larger prospective clinical studies are needed to confirm these findings and to assess the prognostic role of this possible new biomarker for activated coagulation.

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Efficacy and safety of recombinant factor VIIa preparation (NovoSeven) for patients with congenital factor VII deficiency

Japanese Journal of Thrombosis and Hemostasis ◽

10.2491/jjsth.17.695 ◽

2006 ◽

Vol 17 (6) ◽

pp. 695-705 ◽

Cited By ~ 3

Author(s):

Hideji HANABUSA ◽

Kazushige OYAMA ◽

Satoshi WATANABE ◽

Yuzuru SAKAKIBARA ◽

Yuji HIRAMATSU ◽

...

Keyword(s):

Recombinant Factor Viia ◽

Factor Viia ◽

Factor Vii ◽

Efficacy And Safety ◽

Factor Vii Deficiency ◽

Congenital Factor

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In Hemophilia Α Plasma Treated with Emicizumab, Factor IX Activation By Factor VIIa Drives Thrombin Generation

Blood ◽

10.1182/blood-2020-139712 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 17-17

Author(s):

Dougald Monroe ◽

Mirella Ezban ◽

Maureane Hoffman

Keyword(s):

Factor Viii ◽

Tissue Factor ◽

Plasma Levels ◽

Thrombin Generation ◽

Hemophilia A ◽

Factor Viia ◽

Factor Ix ◽

Factor X ◽

Dose Dependent

Background.Recently a novel bifunctional antibody (emicizumab) that binds both factor IXa (FIXa) and factor X (FX) has been used to treat hemophilia A. Emicizumab has proven remarkably effective as a prophylactic treatment for hemophilia A; however there are patients that still experience bleeding. An approach to safely and effectively treating this bleeding in hemophilia A patients with inhibitors is recombinant factor VIIa (rFVIIa). When given at therapeutic levels, rFVIIa can enhance tissue factor (TF) dependent activation of FX as well as activating FX independently of TF. At therapeutic levels rFVIIa can also activate FIX. The goal of this study was to assess the role of the FIXa activated by rFVIIa when emicizumab is added to hemophilia A plasma. Methods. Thrombin generation assays were done in plasma using 100 µM lipid and 420 µM Z-Gly-Gly-Arg-AMC with or without emicizumab at 55 µg/mL which is the clinical steady state level. The reactions were initiated with low (1 pM) tissue factor (TF). rFVIIa was added at concentrations of 25-100 nM with 25 nM corresponding to the plasma levels achieved by a single clinical dose of 90 µg/mL. To study to the role of factor IX in the absence of factor VIII, it was necessary to create a double deficient plasma (factors VIII and IX deficient). This was done by taking antigen negative hemophilia B plasma and adding a neutralizing antibody to factor VIII (Haematologic Technologies, Essex Junction, VT, USA). Now varying concentrations of factor IX could be reconstituted into the plasma to give hemophilia A plasma. Results. As expected, in the double deficient plasma with low TF there was essentially no thrombin generation. Also as expected from previous studies, addition of rFVIIa to double deficient plasma gave a dose dependent increase in thrombin generation through activation of FX. Interestingly addition of plasma levels of FIX to the rFVIIa did not increase thrombin generation. Starting from double deficient plasma, as expected emicizumab did not increase thrombin generation since no factor IX was present. Also, in double deficient plasma with rFVIIa, emicizumab did not increase thrombin generation. But in double deficient plasma with FIX and rFVIIa, emicizumab significantly increased thrombin generation. The levels of thrombin generation increased in a dose dependent fashion with higher concentrations of rFVIIa giving higher levels of thrombin generation. Conclusion. Since addition of FIX to the double deficient plasma with rFVIIa did not increase thrombin generation, it suggests that rFVIIa activation of FX is the only source of the FXa needed for thrombin generation. So in the absence of factor VIII (or emicizumab) FIX activation does not contribute to thrombin generation. However, in the presence of emicizumab, while rFVIIa can still activate FX, FIXa formed by rFVIIa can complex with emicizumab to provide an additional source of FX activation. Thus rFVIIa activation of FIX explains the synergistic effect in thrombin generation observed when combining rFVIIa with emicizumab. The generation of FIXa at a site of injury is consistent with the safety profile observed in clinical use. Disclosures Monroe: Novo Nordisk:Research Funding.Ezban:Novo Nordisk:Current Employment.Hoffman:Novo Nordisk:Research Funding.

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Hemophilic Synovitis: Factor VII and the Potential Role of Extravascular Factor VIIa

Thrombosis Research ◽

10.1016/j.thromres.2010.02.006 ◽

2010 ◽

Vol 125 ◽

pp. S63-S66 ◽

Cited By ~ 2

Author(s):

Paul E. Monahan ◽

Junjiang Sun

Keyword(s):

Potential Role ◽

Factor Viia ◽

Factor Vii

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Life-threatening bleeding in factor VII deficiency: the role of prenatal diagnosis and primary prophylaxis

British Journal of Haematology ◽

10.1111/bjh.13106 ◽

2014 ◽

Vol 168 (3) ◽

pp. 452-455 ◽

Cited By ~ 7

Author(s):

Roula Farah ◽

Jad Al Danaf ◽

Nabil Braiteh ◽

Jean-Marc Costa ◽

Hussein Farhat ◽

...

Keyword(s):

Prenatal Diagnosis ◽

Primary Prophylaxis ◽

Factor Vii ◽

Factor Vii Deficiency ◽

Life Threatening

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Severe Factor VII Deficiency Caused by a Novel Mutation His348 to Gln in the Catalytic Domain

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613793 ◽

2000 ◽

Vol 83 (02) ◽

pp. 239-243 ◽

Cited By ~ 11

Author(s):

Tadashi Matsushita ◽

Tomio Yamazaki ◽

Isamu Sugiura ◽

Tetsuhito Kojima ◽

Hidehiko Saito ◽

...

Keyword(s):

Amino Acid ◽

Sequence Analysis ◽

Catalytic Domain ◽

Novel Mutation ◽

Factor Vii ◽

Wild Type ◽

Extrinsic Pathway ◽

Factor Vii Deficiency ◽

Plasma Factor ◽

Type Factor

SummaryFactor VII is a vitamin K-dependent zymogen that plays a key role in the initiation of the extrinsic pathway. A severe factor VII deficiency was identified in a 45-year old male whose plasma factor VII antigen was less than 60 ng/ml and expressed 5.2% of normal factor VII activity. DNA sequence analysis of the patient’s factor VII gene showed a thymidine to guanine transversion at nucleotide 10968 in exon VIII that results in a novel amino acid substitution of His348 to Gln. The patient was homozygous for this mutation, whereas some of his family members were heterozygous. Both wild type and mutant factor VII were transiently expressed in COS-1 cells. The level of secreted mutant factor VII antigen was only 11.0% of the level of wild type factor VII. In CHO cells stably transfected with the mutant factor VII, only 37.3% of the total labeled FVII was secreted into the conditioned media and the remainder was retained inside the cells. These data suggest this mutation leads to factor VII deficiency due to the impaired secretion of the molecule.

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Presence of Activated Factor VII in Factor IX Concentrates and its Persistence in the Circulation After Infusion

10.1055/s-0039-1684824 ◽

1979 ◽

Cited By ~ 2

Author(s):

U. Seligsohn ◽

C.K. Kasper ◽

B. Østerud ◽

S.I. Rapaport

Keyword(s):

Hemophilia A ◽

Factor Ix ◽

Factor Vii ◽

Amidolytic Activity ◽

Activated Factor Vii ◽

Plasma Factor ◽

Disappearance Time

Six brands of Factor IX concentrates were evaluated for their Factor VII content and for the presence of activated Factor VII through use of a coupled amidolytic assay, insensitive to activated Factor VII, and a clotting assay, sensitive to activated Factor VII. The Factor VII content of the concentrates studied (except for one concentrate purposely produced to exclude Factor VII) varied between 33 to 621 U per vial. All concentrates contained activated Factor VII, as indicated by ratios of Factor VII clotting activity to Factor VII amidolytic activity of from 1.6 to 21.5. Higher ratios were found in two brands of activated concentrates than in non-activated concentrates. In 10 patients infused with Factor IX concentrates, plasma Factor VII activity rose strikingly in the clotting assay but not in the amidolytic assay. Thus, the elevated Factor VII levels by the clotting assay after infusion of Factor IX concentrates stem from circulating activated Factor VII. A mean intravascular half-disappearance time of 144 min was found for activated Factor VII. Its persistence in the circulation makes it important to evaluate the possible role of activated Factor VII in the thrombogenicity of Factor IX concentrates and in their reported effectiveness in treating bleeding in Hemophilia A patients with inhibitors.

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Abstract 2051: Recombinant Factor VIIa Affects Vein Graft Patency and Flow in Rabbits

Circulation ◽

10.1161/circ.116.suppl_16.ii_444 ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

David Mazer ◽

Howard Leong-Poi ◽

Zuhair Alfardan ◽

Zhilan Wang ◽

Beiping Qiang ◽

...

Keyword(s):

Recombinant Factor Viia ◽

Factor Viia ◽

Postoperative Bleeding ◽

Rabbit Model ◽

Graft Patency ◽

Vessel Diameter ◽

Factor Vii ◽

Activity Levels ◽

Graft Occlusion ◽

Plasma Factor

INTRODUCTION: Recombinant factor VIIa (rVIIa) has been used to decrease postoperative bleeding in cardiac surgical patients. However, there is potential for rVIIa to interact with tissue factor expression at the site of new anastomoses resulting in early graft occlusion. This safety study tested the hypothesis that the administration of rVIIa dose-dependently reduces graft patency at the site of new vascular anastomoses comparable in size to human coronaries, in a rabbit model. METHODS: After ACC approval, a reversed venous graft was fashioned in the right carotid artery using autologous right jugular vein with 9 – 0 sutures in 64 anesthetized and heparinized rabbits. Animals were then given either one of three doses of rVIIa (300 ug/kg, 90 ug/kg or 20 ug/kg IV) or placebo (n=16/group). The primary outcome was graft patency, measured by a blinded observer 24 hours postoperatively using vascular ultrasound (HDI 5000cv, 15 MHz probe) and/or direct inspection. Factor VII activity levels were measured from citrated plasma samples with a 1-stage prothrombin time-based assay using rabbit thromboplastin. Data was analyzed using chi-square, fishers exact test, or ANOVA where appropriate, with p<0.05 considered significant. RESULTS: Physiologic variables (ACT, hemoglobin, pH, pCO2) and vessel diameter were similar between groups. Graft patency and flow were significantly reduced, and plasma factor VII levels significantly increased in the rVIIa treated rabbits in a dose-dependent fashion. DISCUSSION: The study suggests that high doses of rVIIa (300 and 90 ug/kg) are associated with an increased incidence of occlusion of new vascular grafts. A clear dose-response effect was observed, suggesting that higher doses may be associated with increased thrombotic outcomes.

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