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Antiplatelet agents in tissue factor-induced blood coagulation
S Butenas1, K M Cawthern, C van't Veer
1Department of Biochemistry, College of Medicine, University of Vermont, Burlington 05405-0068, USA.
Blood
|April 6, 2001
Summary
Platelet inhibitors like abciximab and eptifibatide, targeting glycoprotein IIb/IIIa, significantly reduced thrombin generation in tissue factor-initiated coagulation. This highlights their antithrombotic potential beyond antiplatelet effects.
Area of Science:
- Hematology
- Pharmacology
- Biochemistry
Background:
- Tissue factor (TF)-initiated coagulation is a critical pathway in hemostasis and thrombosis.
- Platelet inhibitors are widely used to prevent thrombotic events, but their precise effects on TF-initiated thrombin generation require further elucidation.
Purpose of the Study:
- To investigate the impact of various platelet inhibitors on TF-initiated whole blood coagulation.
- To assess the role of glycoprotein IIb/IIIa receptor antagonists in modulating thrombin generation and clot formation.
Main Methods:
- Human whole blood from normal donors was used for in vitro coagulation studies.
- Coagulation was initiated with 25 pM TF, with contact pathway suppressed using corn trypsin inhibitor.
- Products of coagulation, including thrombin-antithrombin III complex (TAT) and fibrinopeptide A (FPA), were analyzed by immunoassay.
Main Results:
- Prostaglandin E(1) significantly delayed clotting and platelet activation.
- Acetylsalicylic acid and dipyridamole showed no significant effects on measured coagulation products.
- Glycoprotein IIb/IIIa antagonists (7E3, abciximab, eptifibatide) demonstrated intermediate effects, delaying clot time and FPA release, and reducing TAT formation rate.
Conclusions:
- Disruption of the glycoprotein IIb/IIIa-ligand interaction by specific antagonists not only inhibits platelet aggregation but also decreases the rate of TF-initiated thrombin generation.
- These findings demonstrate a potent antithrombotic effect of glycoprotein IIb/IIIa antagonists that is superimposed on their antiaggregation properties in TF-initiated coagulation.