PB1366 - Enhanced Thrombin Generation Induced by Extracellular Vesicles from Severe COVID-19 Cases

Tuesday, June 25, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

BB

Barbara G. Barion

Postgraduate student
Faculdade de Medicina da Universidade de São Paulo - FMUSP
São Paulo, Sao Paulo, Brazil
RS

Renata F. Saito

Researcher
ICESP - University of São Paulo Medical School, São Paulo, Sao Paulo, Brazil
São Paulo, Sao Paulo, Brazil

Presenting Author(s)

Thaís Dourado Reis Nóbrega, md

physician
Hospital das Clínicas da Faculdade de Medicina da USP, São Paulo, São Paulo, Brazil
São Paulo, Sao Paulo, Brazil

Co-Author(s)

EO

Erica Okazaki

MD
Department of Hematology, Hemotherapy and Cellular Therapy, Hospital das Clínicas of University of São Paulo Medical School (HCFMUSP), São Paulo, Brazil
São Paulo, Sao Paulo, Brazil
YH

Yeh-Li Ho

Physician
Hospital das Clínicas da Faculdade de Medicina da USP, São Paulo, São Paulo, Brazil
São Paulo, Sao Paulo, Brazil
PV

Paula Villaça

Hematologist
Hospital das Clínicas da Faculdade de Medicina da USP, São Paulo, São Paulo, Brazil
São Paulo, Sao Paulo, Brazil
VR

Vanderson Rocha

MD
Department of Hematology, Hemotherapy and Cellular Therapy, Hospital das Clínicas of University of São Paulo Medical School (HCFMUSP), São Paulo, Brazil
São Paulo, Sao Paulo, Brazil
TR

Tania Rubia Flores da Rocha

Pharmaceutical
Hospital das Clínicas da Faculdade de Medicina da USP, São Paulo, São Paulo, Brazil
São Paulo, Sao Paulo, Brazil
FO

Fernanda Andrade Orsi

MD
Department of Hematology, Hemotherapy and Cellular Therapy, Hospital das Clínicas of University of São Paulo Medical School (HCFMUSP), São Paulo, Brazil
São Paulo, Sao Paulo, Brazil

Background: Extracellular vesicles (EVs) are cell membrane fragments released by activated cells under both physiological and pathological conditions. Although EVs have been associated with COVID-19 associated coagulopathy, their pathological effect is still debatable.

Aims: To evaluate whether EVs from COVID-19 patients have procoagulant activity and to determine its association with the severity of the disease.

Methods: EVs were isolated from plasma of patients with mild and severe COVID-19. Their thrombin generation potential was evaluated using a modified thrombin generation assay (TGA). Differences in TGA results between mild and severe COVID-19 were evaluated by Mann-Whitney test. Correlation between TGA values and levels of CRP, D-dimer and circulating EVs was assessed by Spearman's test.

Results: Of the 76 patients enrolled, 54 (71%) had mild COVID-19 and 22 (29%) had severe COVID-19. The median age was 39 years (IQR 31-53) and 51% of patients were male. EVs from severe COVID-19 patients had a higher thrombin generation potential than EVs from mild cases, as evidenced by a higher peak height, endogenous thrombin potential (ETP) and velocity index, and a shorter time to peak. ETP and velocity index were positively correlated with circulating levels of EVs bearing tissue factor (TF), endothelial and platelet antigens. Peak height and time to peak were positively and negatively correlated with EV-TF+ levels, respectively. D-dimer levels were positively correlated with peak height, ETP and velocity index and negatively correlated with time to peak.

Conclusion(s): EVs from COVID-19 patients have a procoagulant potential that is more pronounced in severe cases of the disease and is mainly associated with the presence of EVs bearing TF or derived from endothelial cells and platelets.