Thrombin Formation | ScienceGate

SummaryClinical trials suggest that the risk of thrombosis during coronary angioplasty is lower with ionic contrast agents than with nonionic contrast agents. However, the molecular mechanisms underlying this effect are unknown. This study examined the effects of contrast agents on thrombin formation and its interaction with substrates, inhibitors, and ligands to define potential mechanisms by which contrast agents affect thrombus formation. Two ionic agents, diatrizoate and ioxaglate, and one nonionic agent, ioversol, were studied. Ionic agents inhibited factor X activation by the tissue factor-factor VIIa complex more potently than ioversol (53 ± 3.7, 43.0 ± 1.9, and 26.5 ± 2.4% inhibition by diatrizoate, ioxaglate, and ioversol, respectively, at concentrations of 5%). Ionic contrast agents were potent inhibitors of prothrombinase function, inhibiting thrombin formation by >75% at contrast concentrations of 0.6% (p <0.005). Ioversol inhibited prothrombinase to a significantly lesser extent than ionic agents. Clotting assays suggested that ioxaglate was the most potent inhibitor of thrombin generation in plasma despite having the least effect on fibrin polymerization. Contrast agents inhibited binding of thrombin to fibrin, with ionic agents producing a more potent effect than ioversol (p <0.02). However, contrast agents did not inhibit thrombin-mediated platelet activation, had only a minor effect on inhibition of thrombin by antithrombin III, and did not affect thrombin-hirudin interactions. In summary, these studies identify specific mechanisms by which radiographic contrast agents inhibit thrombin formation and function – i.e. inhibition of tissue factor-dependent factor Xa generation, inhibition of the prothrombinase complex, and inhibition of thrombin binding to fibrin. These findings may help to explain the reduced risk of thrombosis during coronary angioplasty associated with ionic contrast agents.

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Anticoagulant Activity of β2-Glycoprotein I Is Potentiated by a Distinct Subgroup of Anticardiolipin Antibodies

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656368 ◽

1992 ◽

Vol 68 (03) ◽

pp. 297-300 ◽

Cited By ~ 130

Author(s):

Monica Galli ◽

Paul Comfurius ◽

Tiziano Barbui ◽

Robert F A Zwaal ◽

Edouard M Bevers

Keyword(s):

Human Plasma ◽

Anticoagulant Activity ◽

Factor Xa ◽

Type A ◽

Lipid Vesicles ◽

Dependent Manner ◽

Type B ◽

Distinct Subgroup ◽

Glycoprotein I ◽

Thrombin Formation

SummaryPlasmas of 16 patients positive for both IgG anticardiolipin (aCL) antibodies and lupus anticoagulant (LA) antibodies were subjected to adsorption with liposomes containing cardiolipin. In 5 of these plasmas both the anticardiolipin and the anticoagulant activities were co-sedimented with the liposomes in a dose-dependent manner, whereas in the remaining cases only the anticardiolipin activity could be removed by the liposomes, leaving the anticoagulant activity (LA) in the supernatant plasma. aCL antibodies purified from the first 5 plasmas were defined as aCL-type A, while the term aCL-type B was used for antibodies in the other 11 plasmas, from which 2 were selected for this study.Prolongation of the dRVVT was produced by affinity-purified aCL-type A antibodies in plasma of human as well as animal (bovine, rat and goat) origin. aCL-type B antibodies were found to be devoid of anticoagulant activity, while the corresponding supernatants containing LA IgG produced prolongation of the dRVVT only in human plasma.These anticoagulant activities of aCL-type A and of LA IgG's were subsequently evaluated in human plasma depleted of β2-glycoprotein I (β2-GPI), a protein which was previously shown to be essential in the binding of aCL antibodies to anionic phospholipids. Prolongation of the dRVVT by aCL-type A antibodies was abolished using β2-GPI deficient plasma, but could be restored upon addition of β2-GPI. In contrast, LA IgG caused prolongation of the dRVVT irrespective of the presence or absence of β2-GPI.Since β2-GPI binds to negatively-charged phospholipids and impedes the conversion of prothrombin by the factor Xa/Va enzyme complex (Nimpf et al., Biochim Biophys Acta 1986; 884: 142–9), comparison was made of the effect of aCL-type A and aCL-type B antibodies on the rate of thrombin formation in the presence and absence of β2-GPI. This was measured in a system containing highly purified coagulation factors Xa, Va and prothrombin and lipid vesicles composed of 20 mole% phosphatidylserine and 80 mole% phosphatidylcholine. No inhibition on the rate of thrombin formation was observed with both types of aCL antibodies when either β2-GPI or the lipid vesicles were omitted. Addition of β2-GPI to the prothrombinase assay in the presence of lipid vesicles causes a time-dependent inhibition which was not affected by the presence of aCL-type B or non-specific IgG. In contrast, the presence of aCL-type A antibodies dramatically increased the anticoagulant effect of β2-GPI. These data indicate that the anticoagulant activity of aCL-type A antibodies in plasma is mediated by β2-GPI.

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The procoagulant effects of factor V Leiden may be balanced against decreased levels of factor V and do not reflect in vivo thrombin formation in newborns

Thrombosis and Haemostasis ◽

10.1160/th05-05-0375 ◽

2006 ◽

Vol 95 (03) ◽

pp. 434-440 ◽

Cited By ~ 4

Author(s):

Satu Hyytiäinen ◽

Ulla Wartiovaara-Kautto ◽

Veli-Matti Ulander ◽

Risto Kaaja ◽

Markku Heikinheimo ◽

...

Keyword(s):

Tissue Factor ◽

Platelet Rich Plasma ◽

Venous Blood ◽

Factor V Leiden ◽

Factor V ◽

Cord Plasma ◽

Adult Plasma ◽

Thrombin Formation

SummaryThrombin regulation in newborns remains incompletely understood.We studied tissue factor-initiated thrombin formation in cord plasma in vitro, and the effects of Factor VLeiden (FVL) heterozygosity on thrombin regulation both in vitro and in vivo in newborns. Pregnant women with known thrombophilia (n=27) were enrolled in the study. Cord blood and venous blood at the age of 14 days were collected from 11 FVL heterozygous newborns (FVL-positive) and from 16 FVL-negative newborns. Prothrombin fragment F1+2 and coagulation factors were measured. Tissue factor-initiated thrombin formation was studied in cord platelet-poor plasma (PPP) of FVL-negative and -positive newborns, and in both PPP and platelet-rich plasma (PRP) of healthy controls. The endogenous thrombin potential (ETP) in cord PPP or PRP was ∼60% of that in adult plasma, while thrombin formation started ∼55% and ∼40% earlier in cord PPP and PRP, respectively. Further, in FVL-positive newborns thrombin formation started significantly earlier than in FVL-negative newborns. Exogenous activated protein C (APC) decreased ETP significantly more in cord than in adult PRP. In FVL-negative cord plasma 5nM APC decreased ETP by 17.4±3.5% (mean±SEM) compared with only 3.5±3.8% in FVL-positive cord plasma (p=0.01). FVL-positive newborns showed similar levels of F1+2 but significantly decreased levels of factor V compared with FVL negative newborns both in cord plasma (FV 0.82±0.07 U/ml vs. 0.98±0.05 U/ml, p=0.03) and at the age of two weeks (FV 1.15±0.04 U/ml vs. 1.32±0.05 U/ml, p=0.03). In conclusion, newborn plasma showed more rapid thrombin formation and enhanced sensitivity to APC compared with adult plasma. FVL conveyed APC resistance and a procoagulant effect in newborn plasma. Lack of elevated F1+2 levels in FVL-positive infants, however, suggested the existence of balancing mechanisms; one could be the observed lower level of factor V in FVL heterozygous newborns.

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Increased number of thromboxane A2-prostaglandin H2 platelet receptors in active unstable angina and causative role of enhanced thrombin formation

American Heart Journal ◽

10.1016/0002-8703(95)90106-x ◽

1995 ◽

Vol 129 (5) ◽

pp. 873-879 ◽

Cited By ~ 16

Author(s):

Pietro Amedeo Modesti ◽

Andrea Colella ◽

Ilaria Cecioni ◽

Alessandro Costoli ◽

Debora Biagini ◽

...

Keyword(s):

Unstable Angina ◽

Thromboxane A2 ◽

Causative Role ◽

Platelet Receptors ◽

Thrombin Formation

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No Evidence for Enhanced Thrombin Formation through Displacement of Annexin V by Antiphospholipid Antibodies

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613915 ◽

2000 ◽

Vol 83 (05) ◽

pp. 792-794 ◽

Cited By ~ 27

Author(s):

Marie Janssen ◽

George Willems ◽

Robert Zwaal ◽

Edouard Bevers

Keyword(s):

Antiphospholipid Antibodies ◽

Annexin V ◽

Thrombin Formation

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Intensity of thrombin formation and myocardial contractility in patients with ischemic heart disease after coronary stenting

Regional blood circulation and microcirculation ◽

10.24884/1682-6655-2017-16-2-63-69 ◽

2017 ◽

Vol 16 (2) ◽

pp. 63-69

Author(s):

G. A. Berezovskaya ◽

E. S. Klokova

Keyword(s):

Myocardial Contractility ◽

Protein C ◽

Stress Echocardiography ◽

Thrombin Generation ◽

Wall Motion ◽

Primary Pci ◽

Before And After ◽

Wall Motion Abnormalities ◽

Artery Disease ◽

Thrombin Formation

Objective. To study the relationship between the intensity of thrombin formation, estimated by thrombin generation test (TGT) in platelet poor plasma, and myocardial contractility in patients with coronary artery disease (CAD) before and after percutaneous coronary intervention (PCI). Methods. The study included 75 patients with coronary artery disease aged between 40 to 75 years, who underwent primary PCI (10 patients) or elective (65 patients) procedure, as well as 35 individuals matched for age and sex with no clinical signs of CAD. We investigated the venous blood obtained before and after 6 and 12 months following PCI. In the same period, stress echocardiography was performed. The intensity of thrombin formation was assessed using a TGT, formed in platelet poor plasma and the modified reaction mixture by adding human recombinant thrombomodulin (rh-TM) to assess the degree of activation of the protein C system. Results. The association between stress echocardiography parameters characterizing myocardial contractile capacity (ejection fraction (EF) of the left ventricle and a wall motion abnormalities (WMAs)) and TGT parameters, reflecting the intensity (ETP and the Peak) of the thrombin formation rate (V), was identified to be more expressed in patients undergoing primary PCI. The presence of the reverse correlation between EF and WMAs and the percentage reduction of V, ETP and Peak after the addition of rh-TM, as well as a significant association of the EF and WMAs with TGT indicators staged with rh-TM demonstrates the role of protein C system in the changes of myocardial contractility. The intensity of thrombin generation was also associated with hypertension. Conclusion. It was determined that TGT parameters were strongly associated with stress echocardiography parameters. The changes in thrombin generation rate were most closely associated with left ventricular ejection fraction, index of wall motion abnormalities and arterial hypertension, including hypertensive reaction to physical activity.

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Chromogenic anti-Xa test: the ratio between heparin activity units and concentration of apixaban and rivaroxaban

Atherothrombosis Journal ◽

10.21518/2307-1109-2020-2-96-104 ◽

2020 ◽

pp. 96-104

Author(s):

E. V. Titaeva ◽

A. B. Dobrovolsky

Keyword(s):

Oral Anticoagulants ◽

Direct Oral Anticoagulants ◽

Plasma Concentrations ◽

Factor Xa ◽

Activity Test ◽

Formation Dynamics ◽

Test Version ◽

Heparin Activity ◽

The Relationship ◽

Thrombin Formation

Introduction. The direct oral anticoagulants (DOC) therapy does not require alaboratory control; however, it may be required to determine the anticoagulationlevel to choose a treatment strategy if alarge bleeding is developing or emergency surgery is needed.The objective of this experimental study was to investigate the relationship between the residual factor Xa (FXa) activity, anti-Xa activity units oflow molecular weight heparins (LMWH), and the apixaban and rivaroxaban plasma concentrations in a chromogenic anti-Xa assay.Material and methods. Concentrated DOC solutions were prepared by extracting apixaban and rivaroxaban from crushed tablets using methanol and dimethyl sulfoxide, respectively. The resulting solutions were added to the donor plasma pool until final inhibitor concentrations are achieved in the range from 10 to 100 ng/ml plasma. Anti-Xa activity was determined using an STA-compact analyser and the Liquid anti-Xa reagent kit, an analysis protocol, and calibrators designed to control the LMWH therapy. The effect on the thrombin formation dynamics was investigated using the thrombin generation test (TGT) and the PPR reagent as a trigger (final concentrations of tissue factor are 5 pM, and those of phospholipids are 4 μM). TGT curves were analysed using the Thrombinoscope program.Results. It was shown that in the anti-Xa activity test version designed to control the LMWH therapy, there is a high correlation (R2 > 0.98) between thelogarithm of the residual factor Xa activity and the content of apixaban and rivaroxaban in the range from 10 to 80 ng/ml. Rivaroxaban shows about 1.5 times more anti-Xa activity than apixaban at equal concentrations. It was also shown that apixaban and rivaroxaban at doses equal both in concentration and in anti-Xa activity differ in their effect on the thrombin formation dynamics and thrombin inactivation in the TGT.Conclusion. In the LMWH anti-Xa activity test version, the measured range of apixaban and rivaroxaban includes 30 ng/ml and 50 ng/ ml concentrations taken as “cut-off points” to determine the treatment tactics in emergency cases. However, thelack of certified DOC calibratorslimits the use of this test in clinical practice.

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Sulfated agaran with 4,6-pyruvated form from red seaweed Acanthophora muscoides attenuates thrombin formation: in vitro and ex vivo studies

Acta Scientiarum Technology ◽

10.4025/actascitechnol.v43i1.55043 ◽

2021 ◽

Vol 43 ◽

pp. e55043

Author(s):

José Ariévilo Gurgel Rodrigues ◽

Johnny Peter Macedo Feitosa ◽

Sandra de Aguiar Soares ◽

Norma Maria Barros Benevides

Keyword(s):

Thrombin Generation ◽

Ex Vivo ◽

Polyacrylamide Gel Electrophoresis ◽

Deae Cellulose ◽

Continuous Model ◽

Sulfated Polysaccharides ◽

Extrinsic Pathway ◽

Plasma Fraction ◽

Thrombin Formation

In vitro studies have described the sulfated agaran from Acanthophora muscoides as an intrinsic inhibitor of thrombin generation (TG), but not in ex vivo assay. This investigation partially characterized a pyruvate fraction with in vitro and ex vivo effects on an intrinsic/extrinsic pathway-induced thrombin generation (TG) continuous model using 36 or 60-fold diluted mice or defibrinated, normal human plasma. Fraction separated by DEAE-cellulose chromatography exhibited charge homogeneity and non-sulfated polysaccharides (<100 kDa) by agarose and polyacrylamide gel electrophoresis, respectively, using Stains-all alone. Fourier Transform Infrared and Nuclear Magnetic Resonance studies indicated a 4,6-pyruvated agaran-structure. The fraction and heparin had no effect on prothrombin time, but there was a preponderant intrinsic rather than extrinsic pathway inhibition in TG assay; themselves, acting on both free and fibrin bound thrombin activity without chromogenic substrate interaction. Both fractions, desulfated and native, anticipated and induced thrombin formation in activators-devoid or normal plasma. In addition, mice pretreated with fraction (20 mg kg-1, intraperitoneally) reduced intrinsically plasma TG ex vivo after 2h. Heparin suppressed TG in vitro, but induced it ex vivo. Therefore, agaran from A. muscoides blocks TG on in vitro and ex vivo studies, suggesting to evaluate the blood coagulability status.

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