PB1070 - Small and large extracellular vesicles have different tissue factor activity in cancer, sepsis, and COVID-19

Tuesday, June 27, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Ana T. A Sachetto, PhD

Postdoc
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Co-Author(s)

SA

Sierra J. Archibald

Research Technician
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
Yohei Hisada, PhD

Assistant Professor
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
AR

Axel Rosell

Postdoc
Karolinska Institutet
Stockholm, Sodermanlands Lan, Sweden
SH

Sebastian Havervall

PhD Student
Karolinska Institutet
Stockholm, Sodermanlands Lan, Sweden
Nick van Es, MD PhD (he/him/his)

MD
Department of Vascular Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
Amsterdam, Noord-Holland, Netherlands
RN

Rienk Nieuwland

Research Associate
University of Amsterdam
Amsterdam, Noord-Holland, Netherlands
Robert A. Campbell, PhD

Professor
University of Utah, Salt Lake City, UT, USA; Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
Salt Lake City, Utah, United States
Elizabeth A. Middleton, MD

Assistant Professor
University of Utah
Salt Lake City, Utah, United States
Matthew T. Rondina, MD

Professor
Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA; Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA; 4George E. Wahlen Department of Veterans Affairs Medical Center, Geriatric Research, Education, and Clinical Center; Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
Salt Lake City, Utah, United States
CT

Charlotte Thålin

Researcher
Karolinska Institutet
Stockholm, Sodermanlands Lan, Sweden
Nigel Mackman, PhD

Professor
Univerisity of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Background: Cancer cells and activated cells, such as monocytes, release tissue factor (TF)-positive extracellular vesicles (EVs) into the circulation. Levels of TF-positive EVs are increased in a variety of diseases, such as cancer, sepsis, and coronavirus 2019 (COVID-19), and are associated with activation of the coagulation system and thrombosis. EVs are typically isolated from human plasma by centrifugation at 10,000-20,000 g using a bench centrifuge. Isolation of smaller EVs requires higher centrifugation speeds (100,000-200,000 g) and an ultracentrifuge.

Aims: We analyzed TF activity of large and small EV populations in patients with either pancreatic cancer, sepsis and COVID-19.

Methods: Blood samples were collected from individuals who provided informed consent with a protocol approved by the Ethical Review Boards of the different sites. We analyzed EVs from plasma prepared from whole blood samples from pancreatic cancer (n=10), sepsis (n=17), and COVID-19 (n=12) patients. EVs populations were isolated from plasma by sequential centrifugation at 20,000 g (large EVs) and then 100,000 g (small EVs). TF-dependent factor Xa (FXa) generation was measured using an in-house chromogenic assay.

Results: In two sepsis patients with detectable TF activity the activity was associated with large but not small EVs. In contrast, in patients with either pancreatic cancer or COVID-19 we detected high levels of TF activity in both large and small EVs.

Conclusion(s): Our study indicates that isolation of EVs from human plasma by centrifugation at 20,000 g underestimates the level of circulating TF activity associated with EVs. We recommend isolation of EVs using centrifugation at 100,000 g to give a more accurate measure of TF activity levels associated with circulating EVs.