Virus-induced senescence is a driver and therapeutic target in COVID-19.

Derailed cytokine and immune cell networks account for the organ damage and the clinical severity of COVID-19 (refs. 1-4). Here we show that SARS-CoV-2, like other viruses, evokes cellular senescence as a primary stress response in infected cells. Virus-induced senescence (VIS) is indistinguishable from other forms of cellular senescence and is accompanied by a senescence-associated secretory phenotype (SASP), which comprises pro-inflammatory cytokines, extracellular-matrix-active factors and pro-coagulatory mediators5-7. Patients with COVID-19 displayed markers of senescence in their airway mucosa in situ and increased serum levels of SASP factors. In vitro assays demonstrated macrophage activation with SASP-reminiscent secretion, complement lysis and SASP-amplifying secondary senescence of endothelial cells, which mirrored hallmark features of COVID-19 such as macrophage and neutrophil infiltration, endothelial damage and widespread thrombosis in affected lung tissue1,8,9. Moreover, supernatant from VIS cells, including SARS-CoV-2-induced senescence, induced neutrophil extracellular trap formation and activation of platelets and the clotting cascade. Senolytics such as navitoclax and a combination of dasatinib plus quercetin selectively eliminated VIS cells, mitigated COVID-19-reminiscent lung disease and reduced inflammation in SARS-CoV-2-infected hamsters and mice. Our findings mark VIS as a pathogenic trigger of COVID-19-related cytokine escalation and organ damage, and suggest that senolytic targeting of virus-infected cells is a treatment option against SARS-CoV-2 and perhaps other viral infections.

Analysis of cardiopulmonary findings in COVID-19 fatalities: High incidence of pulmonary artery thrombi and acute suppurative bronchopneumonia.

Since its recognition in December 2019, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has rapidly spread globally causing a pandemic that represents the greatest medical challenge in decades. The aim of the study was to evaluate the spectrum of cardiopulmonary pathology of COVID-19 based on (non-minimal invasive) autopsies performed on 14 COVID-19 decedents. Bilateral diffuse alveolar damage (DAD) was found in all patients. Superimposed acute bronchopneumonia was present in 11 of 14 (78.6%) patients and was considered the major cause of death in 2 patients. A key finding was the presence of thrombotic/thromboembolic vascular occlusions. We classified 5 types of pulmonary thrombi: 1. capillary microthrombi (11/14, 78.6%); 2. partially organized thrombi in mid-sized pulmonary arteries with complete vessel occlusion; 3. non-organized thrombi in mid-sized pulmonary arteries that did not completely fill out the vessel lumen and probably represented thromboemboli rather than thrombosis; 4. bone marrow emboli (1/14, 7.1%); and 5. septic pulmonary thromboemboli (1/14, 7.1%). Pulmonary thrombi in mid-sized arteries were noted in 5 of 14 (35.7%) patients, causing pulmonary infarction and/or pulmonary hemorrhage. All patients had evidence of chronic cardiac disease, including myocardial hypertrophy (13/14, 92.9%), mild to marked coronary artery atherosclerosis (14/14, 100%) and focal myocardial fibrosis (3/14, 21.4%). Acute myocardial infarction was found as concurrent cause of death in 3 (21.4%) patients, and significant cardiac hypertrophy (heart weight 750 g) was present in 1 (7.1%) patient with ATTR-positive cardiac amyloidosis. The autopsy findings confirm that COVID-19 is a systemic disease, with major involvement of the lungs, that increases the risk of cardiac and vascular complications including acute myocardial injury and thrombotic/thromboembolic events. Secondary acute bronchopneumonia is a common complication in patients with COVID-19 and may be the major cause of death.