OC 38.4 - Preventing CD62P-mediated leukocyte infiltration and activation enhances thrombus resolution in mice

Monday, July 11, 2022

11:30 AM – 11:45 AM

Location: ExCel Center, ICC Capital Suite Room 17

Presentation Format: In-Person

Presenting Author(s)

Julia B. Pointner, PhD

Postdoc
Medical University of Vienna
Vienna, Wien, Austria

Co-Author(s)

PH

Patrick Haider

PhD Student
Department of Internal Medicine II, Division of Cardiology / Medical University of Vienna
Vienna, Wien, Austria
PS

Petra L. Szabo

PhD Student
Center for Biomedical Research, Medical University of Vienna
Vienna, Wien, Austria
CK

Christoph Kaun

Technician
Department of Internal Medicine II, Division of Cardiology / Medical University of Vienna
Vienna, Wien, Austria
MB

Mira Brekalo

Technician
Department of Internal Medicine II, Division of Cardiology / Medical University of Vienna
Vienna, Wien, Austria
Manuel Salzmann, PhD

Postdoc
Medical University of Vienna
Vienna, Wien, Austria
KS

Karl Schneider

PostDoc
Center for Biomedical Research, Medical University of Vienna
Vienna, Wien, Austria
SB

Sonja Bleichart

PhD Student
Department of Surgery, Medical University of Vienna,
Vienna, Wien, Austria
AK

Attila Kiss

Research Associate
Center for Biomedical Research, Medical University of Vienna
Vienna, Wien, Austria
CH

Christian Hengstenberg

Professor
Department of Internal Medicine II / Medical University of Vienna
Vienna, Wien, Austria
CB

Christine Brostjan

Associate Professor
Department of Surgery, Medical University of Vienna,
Vienna, Wien, Austria
HB

Helga Bergmeister

Associate Professor
Center for Biomedical Research, Medical University of Vienna
Vienna, Wien, Austria
Alice Assinger, PhD

Associate professor
Medical University of Vienna
Vienna, Wien, Austria
BP

Bruno Podesser

Professor
Medical University of Vienna
Vienna, Wien, Austria
Johann Wojta, PhD

Professor
Medical University of Vienna
Vienna, Wien, Austria
Philipp Hohensinner

Professor
Medical University of Vienna
Vienna, Wien, Austria

Background: Deep vein thrombosis and its complication pulmonary embolism and is a major health problem with an average annual incidence rate of 104 to 183 per 100 000 person-years. After thrombus formation its resolution is essential to re-establish blood flow.

Aims: In this funded study (Austrian Science Fund (FWF)), we aim to analyse the effect of CD62P-mediated cell migration and activation on thrombus resolution post thrombus formation.

Methods: Thrombus formation was induced by inferior vena cava ligation and mice were treated after 1 day with a CD62P-blocking antibody or isotype. The thrombus and the surrounding vessel were extracted for immunohistochemistry or flow cytometry. Data were analysed by unpaired Student’s t-test or ANOVA.

Results: Localising neutrophils and macrophages in the thrombotic lesion revealed that they enter the thrombus and vessel wall from the caudal site. Neutrophils were predominantly present one day and monocytes/macrophages three days after vessel ligation. As leukocyte extravasation is promoted by endothelial and platelet CD62P, we blocked CD62P at day 1 after thrombus formation. This reduced aggregates between platelets and neutrophils or Ly6Chigh monocytes compared to isotype-treated controls, leading to diminished neutrophils and Ly6Chigh monocytes in the cranial thrombus part. Continuous observation of thrombus volume by ultrasound revealed an accelerated thrombus breakdown after blocking CD62P, confirmed by decreased thrombus weight and length. To identify CD62P-mediated effects on thrombus structure, we applied scanning electron microscopy and observed reduced fibrin density in thrombi of anti-CD62P-antibody-treated mice. Corresponding, we found reduced tissue factor expression associated with macrophages and reduced neutrophil activation after CD62P inhibition.

Conclusion(s): We propose a CD62P-mediated cross talk of vessel wall, platelets, monocytes and neutrophils resulting in activation of innate immune cells and increased tissue factor expression. This initial activation of immune cells strengthens the thrombus and delays subsequent resolution processes.