OC 57.4 - Decreased DNase activity in severe COVID-19 correlates with increased circulating NET burden

Tuesday, July 12, 2022

11:30 AM – 11:45 AM

Location: ExCel Center, ICC Capital Suite Room 2-4

Presentation Format: In-Person

Presenting Author(s)

Caroline P. Martens, MD

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

Co-Author(s)

SK

Sirima Kraisin

Postdoctoral Researcher
Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
Leuven, Vlaams-Brabant, Belgium
LV

Leydi Carolina Velásquez Pereira

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

Renaud Lavend'homme

Research assistant
Center for Molecular and Vascular Biology, University of Leuven, Belgium
Leuven, Vlaams-Brabant, Belgium
CJ

Cato Jacobs

Clinical Biomedical Scientist
Laboratory for Clinical Infectious and Inflammatory Disorders, UZ Leuven
Leuven, Vlaams-Brabant, Belgium
LV

Lore Vanderbeke

PhD Candidate
Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, KU Leuven
Leuven, Vlaams-Brabant, Belgium
EW

Els Wauters

Pulmonologist
Department of Pneumology, UZ Leuven; Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department of Chronic Diseases and Metabolism, KU Leuven
Leuven, Vlaams-Brabant, Belgium
PV

Peter Verhamme

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

Thilo Witsch

Attending Physician Interventional Cardiology
Invasive Cardiology, University Hospital Basel; Department of Cardiology and Angiology I, University Heart Center, Freiburg-Bad Krozingen; Faculty of Medicine, University of Freiburg, Freiburg, Germany
Freiburg, Baden-Wurttemberg, Germany
Marc Jacquemin, MD

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

Joost Wauters

Intensivist
Medical Intensive Care Unit, Department of Internal Medicine, UZ Leuven; Laboratory for Clinical Infectious and Inflammatory Disorders, Department of Microbiology, Immunology and Transplantation, KU Leuven
Leuven, Vlaams-Brabant, Belgium
Kimberly Martinod, PhD

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

Background: COVID-19 represents a “perfect storm” for release of neutrophil extracellular traps (NETs) and resultant pathology from immunothrombosis. Levels of NETs in circulation are regulated by endogenous plasma DNases, which have been shown to be reduced in various diseases including myocardial infarction and sepsis. We previously reported elevated NET biomarkers in admission samples from our first wave study cohort.

Aims: To characterize DNase activity and biomarkers of released NETs in the context of COVID-19 immunothrombosis.

Methods: With ethical permission and informed consent, we prospectively collected citrated platelet-poor plasma samples from patients admitted to the COVID ward (55 patients) or intensive care unit (216 patients) from March 2020-December 2021 as part of the COntAGIouS trial at UZ Leuven in Belgium (NCT04327750), with special attention paid to sample preparation and storage to preserve NET fragments and DNase activity. Consecutive samples were obtained within 48 hours of admission, between days 6-8, and upon hospital or ICU discharge. Analysis was batch-performed for MPO, MPO-DNA, PF4, sP-selectin, citrullinated histones, DNase activity, VWF:Ag, and FVIII:Ag levels.

Results: In ICU patients, MPO, VWF, sP-selectin, and NET biomarkers were elevated throughout hospitalization, peaking at day 6-8 after admission, whereas PF4 and FVIII remained highly elevated through the time of ICU discharge. DNase activity was decreased in admission samples, normalized at day 6-8, and strongly increased at the time of discharge, indicating a potential compensatory mechanism. DNase activity was negatively correlated with MPO-DNA values (r = -0.29, P=0.0013). sPselectin and NET levels were significantly higher in admission samples for patients who experienced a thrombotic event in the period during hospitalization, including pulmonary embolism, DVT, myocardial infarction, and/or stroke.

Conclusion(s): Elevated NET levels and decreased DNase activity in plasma are correlated in severe COVID-19, together with elevated markers of thrombotic risk. Approaches to restore DNase activity in plasma may be beneficial in COVID-19-associated immunothrombosis.