OC 34.1 - Chronic thromboinflammation results in cardiac dysfunction in an experimental mouse model of deep vein thrombosis in a PAD4-dependent manner

Monday, June 26, 2023

10:45 – 11:00 ET

Room: 520

Session Available As: On-Demand

Presenting Author(s)

Stijn Van Bruggen, MA, Ir. (he/him/his)

PhD candidate
Center of Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
Leuven, Vlaams-Brabant, Belgium

Co-Author(s)

CS

Casey Sheehy

Lab Technician
Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA
Boston, Massachusetts, United States
MS

Mathias Stroobants

Lab Technician
Center of Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
Leuven, Vlaams-Brabant, Belgium
Lukas Heger, MD (he/him/his)

Research Fellow
Program in Cellular and Molecular Medicine, Boston Children's Hospital / Harvard Medical School Department of Cardiology and Angiology University Medical Center, Faculty of Medicine
Rottenburg am Neckar, Germany
Denisa Wagner, PhD (she/her/hers)

Senior Investigator and Edwin Cohn Professor of Pediatrics
Boston Children's Hospital/Harvard Medical School
Boston, Massachusetts, United States
Kimberly Martinod, PhD

Assistant Professor
Center of Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
Leuven, Vlaams-Brabant, Belgium

Background: The effects of having suffered from a thrombus extend beyond the local confinements of the thrombus region, and results in a decreased quality of life. Neutrophil extracellular trap (NET) release, involving the activation of peptidylarginine deiminase 4 (PAD4), is important in thrombus formation. The systemic impact of thrombus induced neutrophil activation and NET release remains to be addressed.

Aims: To study how local thrombus-induced inflammation could progress towards a systemic inflammatory state, resulting in tissue damage and organ dysfunction.

Methods: Inferior vena cava (IVC) stenosis in mice was used to generate deep vein thrombosis (DVT). Systemic effects were analyzed after two weeks.

Results: Neutrophils isolated from DVT surgery mice showed increased levels of NET formation compared to neutrophils from sham-operated animals (Figure 1A,B). In these animals, left ventricular (LV)systolic function decreased as measured by echocardiography. In systemic (PAD4-/-) or neutrophil-specific (MRP8Cre+ X PAD4fl/fl, Ne-PAD4-/-) PAD4-knockout mice, this decrease in systolic function was absent (Figure 1C). Histological examination of the heart showed increased cardiomyocyte size in PAD4+/+ but not PAD4-/- mice, compared to sham surgery (Figure 1D). In addition, flow cytometric analysis revealed increased levels of cardiac infiltrated neutrophils in DVT surgery mice, compared to sham or PAD4-/- mice.

Conclusion(s): Here we show that local thrombus formation results in sustained systemic activation of circulating neutrophils after 14 days. We identify chronic neutrophil activation and infiltration in the heart muscle, following DVT, as a mechanism in adverse myocardial remodeling, finally leading to LV systolic dysfunction. Loss of systemic, and neutrophil specific PAD4 prevented the development of cardiac remodeling and dysfunction following DVT. Therefore, PAD4 inhibition may also have a protective effect on peripheral organs in settings of DVT.

Learning Objectives:

Researcher will be able to apply an experimental model of DVT
Adapt current best practices in clinical treatment post deep vein thrombosis
Understand the systemic impact of thrombus induced NET formation post DVT