Background Platelet activation is documented in COVID-19, but data on platelet-derived mediators are scarce. Objective To examine the levels of various platelet-derived mediators in relation to adverse outcomes defined as the need for treatment at intensive care unit (ICU) and/or respiratory failure (RF) and 60-day total mortality in hospitalized COVID-19 patients. Methods Plasma levels of RANTES/CCL5, PF4/CXCL4, ENA78/CXCL5, NAP-2/CXCL7, SDF-1/CXCL12, P-selectin, soluble CD40 ligand (sCD40L) and vascular endothelial cell growth factor A (VEGF-A) were measured in 245 hospitalized COVID-19 patients and in a subpopulation of the patients, also at three, six and 12 months after hospitalization. Results Our main findings were: (i) High levels of P-selectin was associated with ICU/RF, while low levels of PF4/CXCL4, ENA-78/CXCL5 and NAP-2/CXCL7 were associated with 60-days mortality. (ii) Most of the mediators were normalized after hospitalization, but plasma levels of sCD40L, ENA-78/CXCL7 and VEGF-A were markedly elevated compared to healthy controls for up to 12 months after hospitalization. (iii) In vitro , inactivated SARS-CoV-2 induced a dose-dependent release of NAP-2, P-selectin, RANTES, sCD40L and VEGF-A from isolated platelets. Conclusion Our findings underscore the role of platelet-derived inflammatory mediators in the pathogenesis of COVID-19, potentially involving direct effects of SARS-CoV-2. The study also points to a persistent platelet activation following hospitalization.
Lunden et al. (Wed,) studied this question.