Inhibitory potential of anticoagulant and antiplatelet agents on COVID-19- induced NETs release

ABSTRACT

Background: Neutrophil extracellular traps (NETs) release is the one of the main mechanisms behind hypercoagulability and disease severity in severe acute respiratory syndromes. The identification of drugs capable of inhibiting this pathological mechanism is mandatory. Aim(s) Neutrophil extracellular traps (NETs) release is the one of the main mechanisms behind hypercoagulability and disease severity in severe acute respiratory syndromes. The identification of drugs capable of inhibiting this pathological mechanism is mandatory. Method(s) Healthy neutrophils (20 x 103/well) were stimulated with phorbol myristate acetate (PMA) or sera from severe COVID-19 patients (n = 16) in the presence or absence of dipyridamole (10 muM), aspirin (1 mM) and heparin (50 mug/mL). Neutrophils nuclei were stained with nuclear red and incubated with a medium containing the non-permeable cell membrane marker Sytox Green. Cell images were obtained using IncuCyte ZOOM and the number of cells that suffered netosis was monitored over time. NETs release was determined after 1 h of incubation and the percentage of NETs was calculated dividing the number of green cells by the total number of cells per well. Result(s) COVID-19 induced NETs was lower in neutrophils pretreated with heparin (median 2.6%, IQR 2.6-2.9) than in non-treated neutrophils (median 3.6%, IQR 3.2-4.0, p < 0.0001). Pretreatment with dipyridamole and aspirin did not change the effect of COVID-19 sera in inducing NETs. A similar pattern of inhibition was observed with PMA stimulation, in which heparin decreased NETs by 3 times (NETs after PMA 43.2% and NETs after PMA and heparin 14.8%) while dipyridamole and aspirin did not significantly affect the release of PMA-induced NETs (Figure 1). Figure 2 illustrates the identification of NETs. Conclusion(s) Heparin was capable of inhibiting in vitro NETs release induced by COVID-19, while dipyridamole and aspirin had no significant effect on this process. Such findings are in line with evidence that heparin use can improve COVID-19 prognosis. (Figure Presented).