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Thromb Haemost 2019; 119(06): 916-929
DOI: 10.1055/s-0039-1685139
Cellular Haemostasis and Platelets
Georg Thieme Verlag KG Stuttgart · New York

The Direct Thrombin Inhibitors Dabigatran and Lepirudin Inhibit GPIbα-Mediated Platelet Aggregation

Katharina Trabold   *
1   Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
,
Stephanie Makhoul   *
1   Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
,
Stepan Gambaryan
1   Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
2   Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
3   Department of Cytology and Histology, St. Petersburg State University, St. Petersburg, Russia
,
Joanne van Ryn
4   Department of Cardiometabolic Disease Research, Boehringer Ingelheim Pharma GmbH, Biberach, Germany
,
Ulrich Walter
1   Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
,
Kerstin Jurk
1   Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
› Institutsangaben
Funding This study was supported by a research grant from Boehringer Ingelheim (to K.J. and U.W.) and by the German Federal Ministry of Education and Research (BMBF 01EO1003 and 01EO1503 to K.J. and U.W.). S.G. was supported by a grant from RFBR N° 17–00–00141 (17–00–00139).
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Publikationsverlauf

17. September 2018

20. Februar 2019

Publikationsdatum:
20. April 2019 (online)

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Abstract

The direct thrombin inhibitor (DTI) dabigatran is a non-vitamin K antagonist oral anticoagulant for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation. In addition to its anti-thrombotic efficacy, dabigatran has been suggested to exert some pro-thrombotic effect due to fostering the ligation of thrombin to its high affinity platelet receptor glycoprotein (GP) Ibα in patients with atrial fibrillation. On the other hand, we provided evidence that a member of another class of DTIs, lepirudin, stimulates the inhibitory cyclic guanosine monophosphate (cGMP)/soluble guanylate cyclase pathway in human platelets. Here, we investigated the effect of lepirudin and dabigatran spiked to platelets from healthy volunteers on GPIbα-mediated platelet aggregation and agglutination. Ristocetin/von Willebrand factor (vWF)-induced aggregation of platelets in the presence or absence of plasma was significantly inhibited by lepirudin, dabigatran and D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (PPACK). However, ristocetin/vWF-mediated platelet agglutination and binding of vWF to platelets were not affected by the DTIs. The anti-aggregatory effect was confirmed by using the GPIbα-specific agonist echicetin beads for human and murine platelets. DTIs diminished echicetin beads-induced Syk Y352 phosphorylation (used here as readout for an early signal occurring during echicetin-induced platelet aggregation), but did not inhibit adenosine diphosphate- or thromboxane A2-induced platelet aggregation. Thrombin was not generated in response to ristocetin/vWF or echicetin beads and therefore did not explain the inhibitory effect of the DTIs. Therapeutic concentration of lepirudin and dabigatran did not affect significantly platelet vasodilator-stimulated phosphoprotein S239 phosphorylation or cGMP and cyclic adenosine monophosphate levels. These data suggest that the DTIs, lepirudin and dabigatran, impair platelet activation measured during platelet aggregation induced by ristocetin/vWF or echicetin beads.

Keywords

platelets - aggregation - direct thrombin inhibitors - von Willebrand factor - GPIb/V/IX

* Both the authors contributed equally and share the first authorship.


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