OC 45.2 - Foudroyant cerebral venous (sinus) thrombosis triggered through CLEC-2 and GPIIb/IIIa dependent platelet activation

Monday, July 11, 2022

3:00 PM – 3:15 PM

Location: ExCel Center, ICC Capital Suite Room 8&9

Presentation Format: In-Person

Co-Author(s)

David Stegner, PhD

Professor
Institute of Experimental Biomedicine - Chair I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
Würzburg, Bayern, Germany

Presenting Author(s)

Vanessa Göb, MSc

PhD student
University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg
Würzburg, Bayern, Germany

Co-Author(s)

VK

Viola Krenzlin

Postdoctoral fellow
University of Mainz
Mainz, Rheinland-Pfalz, Germany
Sarah Beck, PhD

Postdoc
Institute of Experimental Biomedicine - Chair I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
Würzburg, Bayern, Germany
KH

Katherina Hemmen

Postdoc
Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Germany
Würzburg, Bayern, Germany
MS

Michael K. Schuhmann

Group leader
University Hospital Würzburg
Würzburg, Bayern, Germany
BS

Barbara Schörg

Postdoctoral fellow
Eberhard Karls University Tübingen
Tübingen, Baden-Wurttemberg, Germany
CH

Christian Hackenbroch

PhD Student
Institute of Experimental Biomedicine - Chair I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
Würzburg, Bayern, Germany
FM

Frauke May

Principal Scientist
CSL Behring Innovation GmbH
Marburg, Hessen, Germany
Philipp Burkard, MSc

PhD student
Institute of Experimental Biomedicine - Chair I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Biomaging, University of Würzburg, Germany
Würzburg, Bayern, Germany
JP

Jürgen Pinnecker

Technician
Rudolf Virchow Center, University of Würzburg
Würzburg, Bayern, Germany
AZ

Alma Zernecke

Professor
University Hospital Würzburg
Würzburg, Bayern, Germany
PR

Peter Rosenberger

Professor
University Hospital Tübingen
Tübingen, Baden-Wurttemberg, Germany
AG

Andreas Greinacher

MD, Head of
Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Germany
Greifswald, Mecklenburg-Vorpommern, Germany
BP

Bernd J. Pichler

Professor
Eberhard Karls University Tübingen
Tübingen, Baden-Wurttemberg, Germany
KH

Katrin Heinze

Professor
Rudolf Virchow Center for Integrative and Translational Biomaging University of Würzburg, Germany
Würzburg, Bayern, Germany
GS

Guido Stoll

Professor
University Hospital Würzburg
Würzburg, Bayern, Germany
BN

Bernhard Nieswandt

Professor
Institute of Experimental Biomedicine - Chair I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Biomaging, University of Würzburg, Germany
Würzburg, Bayern, Germany

Background: Cerebral venous (sinus) thrombosis (CVST, CVT) is an unusual manifestation of venous thrombosis causing severe neurological impairment and seizures. Molecular mechanisms underlying CVT, potentially involving pathological platelet activation, are currently unknown.

Aims: Recent studies suggested a role for platelet ITAM signaling in venous thrombosis. Therefore, we investigated a potential role of the hemITAM receptor CLEC-2 in CVT.

Methods: Mice were monitored following the administration of the anti-CLEC-2 antibody, INU1, or its fab-fragment. Platelet count and activation were assessed by flow cytometry, and thrombus formation was analyzed intravitally or in tissue sections using different imaging modalities.

Results: Administration of INU1 fab-fragments, but not INU1-IgG, triggered within minutes a CVT-like thrombotic syndrome in mice, characterized by tonic/myoclonic seizures, platelet consumption and death. Brain autopsy showed thrombi mainly in the cortical venules. Transcranial intravital microscopy revealed rapidly progressing thrombosis in the superior sagittal sinus, a main site of CVT in humans. PET/MRI and light-sheet fluorescence microscopy confirmed that INU1-fab induced thrombosis is limited to cerebral veins.
Defective CLEC-2 signaling protected mice from INU1-fab induced symptoms and lethality. Lack of dense granule secretion or treatment with Aspirin or Clopidogrel delayed the onset of CVT but did not prevent thrombocytopenia or lethality. In contrast, prophylactic GPIIb/IIIa blockade abolished platelet consumption, CVT and death. Unlike heparin, the current first line treatment of CVT, GPIIb/IIIa blockade was also highly beneficial when applied therapeutically after symptom onset.

Conclusion(s): These results point to aberrant platelet activation as a major trigger of CVT and suggests targeting GPIIb/IIIa or CLEC2-ITAM signaling as a potential therapeutic option in foudroyant CVT.