Platelets are Hyperactivated but Show Reduced Glycoprotein VI Reactivity in COVID-19 Patients

Abstract

No Abstract

Platelet Phenotype Analysis of COVID-19 Patients Reveals Progressive Changes in the Activation of Integrin αIIbβ3, F13A1, the SARS-CoV-2 Target EIF4A1 and Annexin A5

“…Thrombocytopenia was found to be associated with disease severity ( 23 – 26 ) and platelet apoptosis observed in COVID-19 patients requiring intensive care unit treatment ( 27 ). In line with these findings, severely ill COVID-19 patients display elevated markers of platelet activation ( 9 , 26 , 28 – 30 ) and elevated plasma levels of platelet activation markers ( 31 , 32 ).…”

“…Thus, the drop of the activated αIIbβ3 complex on platelets of non-surviving COVID-19 patients, observed in the current study, may be attributed to a generally declining amount of total ITGA2B in their platelets due to hyper-activation. Strikingly, it has already been shown that platelets from COVID-19 patients, activated via the GPVI receptor ( 30 , 32 ) show a reduced activation of the integrin-αIIbβ3 complex in comparison to controls. To establish a possible link to our results of diminished ITGA2B in COVID-19, it should be noted that the activation of the integrin αIIbβ3 complex via its altered conformation is quantified by the binding of the antibody PAC-1.…”

“…It is also noteworthy that platelet exhaustion and hypo-responsiveness of platelets have been observed in COVID-19 patients. Platelets of COVID-19 patients show hypo-reactivity in response to in-vitro stimulation ( 9 , 29 , 30 , 32 , 33 ), indicating prior platelet hyper-activation and resulting hypo-responsiveness in COVID-19 patients ( 34 ). However, little is known about more detailed molecular changes in platelets in the context of SARS-CoV-2 infection and the course of the disease.…”

COVID-19 and biomarkers of thrombosis: focus on von Willebrand factor and extracellular vesicles

“…Platelet hyperactivation in patients with COVID-19 has been reported by several groups [24,25,58,61]. Platelet-leukocyte interactions contribute to the pathophysiology of some viral infections and may play a similar role in SARS-CoV-2 infection.…”

“…In addition, an analysis of blood smears from COVID-19 patients revealed platelet engulfment by lymphocytes [58]. Leopold et al [61] also found higher levels of platelet-neutrophil aggregates in patients hospitalized with COVID-19 (n = 35). In their study of COVID-19 patients within 72 h of ICU admission (n = 35), Hottz et al [24] found higher levels of platelet-monocyte aggregates in ICU patients than asymptomatic/mildly symptomatic patients or healthy controls.…”