“What’s the best gift to give this year? Consider the gift of health. It’s priceless. As we head into the holiday and winter season now is the time to think about protection for ourselves and our families. So many of us miss being with our friends and family last year. For those who are at higher risk of severe illness from COVID-19 and who are eligible for a COVID-19 booster dose, go out now and get your extra booster dose to protect you. And for those who are not yet vaccinated, including our children, teens, and adolescents who are now all eligible for vaccination, getting vaccinated this week will set you up to being fully protected in time for the holidays and by the end of the year. Thank you. I’ll now turn it over to Dr. Fauci.” -Rochelle Walensky
At a press conference on November 17th, CDC Director Walensky appeared with Fauci’s Covid Task Force. Read the full transcript.
In SARS-CoV-2-infected humans, disease progression is often associated with acute respiratory distress syndrome involving severe lung injury, coagulopathy, and thrombosis of the alveolar capillaries. The pathogenesis of these pulmonary complications in COVID-19 patients has not been elucidated. Autopsy study of these patients showed SARS-CoV-2 virions in pulmonary vessels and sequestrated leukocytes infiltrates associated with endotheliopathy and microvascular thrombosis. Since SARS-CoV-2 enters and infects target cells by binding its spike (S) protein to cellular angiotensin-converting enzyme 2 (ACE2), and there is evidence that vascular endothelial cells and neutrophils express ACE2, we investigated the effect of S-proteins and cell–cell communication on primary human lung microvascular endothelial cells (HLMEC) and neutrophils expression of thrombogenic factors and the potential mechanisms. Using S-proteins of two different SARS-CoV-2 variants (Wuhan and Delta), we demonstrate that exposure of HLMEC or neutrophils to S-proteins, co-culture of HLMEC exposed to S-proteins with non-exposed neutrophils, or co-culture of neutrophils exposed to S-proteins with non-exposed HLMEC induced transcriptional upregulation of tissue factor (TF), significantly increased the expression and secretion of factor (F)-V, thrombin, and fibrinogen and inhibited tissue factor pathway inhibitor (TFPI), the primary regulator of the extrinsic pathway of blood coagulation, in both cell types. Recombinant (r)TFPI and a thiol blocker (5,5′-dithio-bis-(2-nitrobenzoic acid)) prevented S-protein-induced expression and secretion of Factor-V, thrombin, and fibrinogen. Thrombomodulin blocked S-protein-induced expression and secretion of fibrinogen but had no effect on S-protein-induced expression of Factor-V or thrombin. These results suggests that following SARS-CoV-2 contact with the pulmonary endothelium or neutrophils and endothelial–neutrophil interactions, viral S-proteins induce coagulopathy via the TF pathway and mechanisms involving functional thiol groups. These findings suggest that using rTFPI and/or thiol-based drugs could be a viable therapeutic strategy against SARS-CoV-2-induced coagulopathy and thrombosis. View Full-Text