OC 05.4 - Defective nitric oxide production and increased reactive oxygen species generation by platelets from COVID-19 patients.

Saturday, June 24, 2023

13:45 – 14:00 ET

Room: 511

Session Available As: On-Demand

Presenting Author(s)

Eleonora Petito, Post Doc

Post Doc
Department of Medicine and Surgery, Section of Internal and Cardiovascular Medicine, University of Perugia
Perugia, Umbria, Italy

Co-Author(s)

Giuseppe Guglielmini, PhD

Biologist, PhD
Department of Medicine and Surgery, Section of Internal and Cardiovascular Medicine, University of Perugia
Perugia, Umbria, Italy
ED

Edoardo De Robertis

Prof.
University of Perugia, Department of Medicine and Surgery, Division of Anaesthesia, Analgesia, and Intensive Care
Perugia, Umbria, Italy
EG

Elisa Giglio

PhD student
Department of Medicine and Surgery, Section of Internal and Cardiovascular Medicine, University of Perugia
Perugia, Umbria, Italy
CB

Cecilia Becattini, PhD

Professor
University of Perugia
Perugia, Umbria, Italy
EF

Emanuela Falcinelli

Post Doc
Department of Medicine and Surgery, Section of Internal and Cardiovascular Medicine, University of Perugia
Perugia, Umbria, Italy
LF

Laura Franco

Dr.
Department of Medicine and Surgery, Section of Internal and Cardiovascular Medicine, University of Perugia
Perugia, Umbria, Italy
Francesca Tondi, MS

Graduate student
University of Perugia, Departement of Medicine and Surgery, Section of Internal and Cardiovascular Medicine
Perugia, Umbria, Italy
FG

Fabio Gori

Dr.
University of Perugia, Department of Medicine and Surgery, Section of Anesthesia, Intensive Care, and Pain Medicine
Perugia, Umbria, Italy
GV

Gaetano Vaudo

Prof.
Unit of Internal Medicine, Terni University Hospital, 05100, Terni , Italy
Terni, Umbria, Italy
VC

Vittorio Cerotto

Dr.
Section of Anesthesia, Intensive Care and Pain Medicine, Department of Emergency and Urgency, ASL 1 Umbria, 06012, Città di Castello, Italy.
Città di Castello, Umbria, Italy
UP

Ugo Paliani

Dr.
Division of Internal Medicine, ASL 1 Umbria, 06012, Città di Castello, Italy
Città di Castello, Umbria, Italy
Paolo Gresele, MD, PhD

Professor
Dept. of Medicine and Surgery, University of Perugia
Perugia, Umbria, Italy

Background: Oxidative stress and decreased NO bioavailability contributes, along with the cytokine storm, to COVID-19 adverse outcome. Hyper-reactive platelets are associated with COVID-19-related thrombosis. Platelet-generated ROS and NO play a pivotal and opposite role in platelet function, but no studies have assessed them in COVID-19.

Aims: To analyze platelet ROS- and NO-production in COVID-19 patients, comparing it to healthy subjects (HS) and critically ill non-COVID-19 patients.

Methods: Venous blood was collected from 24 COVID-19 patients hospitalized in ordinary ward (non-ICU), 11 COVID-19 patients in intensive care unit (ICU), 24 age- and sex-matched healthy subjects (HS), and 21 age- and sex-matched patients in ICU not for COVID-19 (non-COVID-19-ICU). Collagen-triggered platelet NO- and ROS-generation were assessed by flow-cytometry (DAF-FM-DA and DCF as fluorescent probes). Soluble P-selectin and platelet-derived microvesicles were measured as platelet activation markers.

Results: Soluble P-selectin and platelet-derived microvesicles were significantly increased in COVID-19 patients, compared to HS and to non-COVID-19-ICU, but significantly more in ICU COVID-19 patients (Figure 1A-B).
HS and non-COVID-19-ICU platelets showed a dose-dependent and comparable increase of NO-production in response to collagen (Figure 2A). On the contrary, COVID-19 platelets, both from non-ICU and ICU patients, did not produce NO in response to collagen (Figure 2A).
Platelets from COVID-19 patients, both non-ICU and ICU, showed a significant increase in ROS-production, especially with the lowest dose of collagen, compared with unstimulated platelets, differently from HS and non-COVID-19-ICU (Figure 2B).

Conclusion(s): COVID-19 platelets show a strikingly defective NO-production, independent from disease severity, while platelets from non-COVID-19-ICU generate NO normally, showing a selective SARS-CoV-2 infection-related defect of platelet NO-production. We also show an increase in ROS-production by COVID-19 platelets, and an alteration present however also in non-COVID-19-ICU patients and probably related to critical illness.
Platelets may play a role in the previously reported decreased NO-bioavailability and oxidative stress in COVID-19.

Learning Objectives:

appreciate the contribution of oxidative stress and decreased NO bioavailability in the thrombotic complications of COVID-19.
figure out defective platelet ROS- and NO-production in mild and severe COVID-19 patients, comparing it to healthy subjects and critically ill non-COVID-19 patients.
comprehend if a correlation between platelet ROS- and NO-production and COVID-19 adverse outcome exists.