Circulating Sars-cov-2 Spike Protein 1 Causes Microarteriolar Oxidative Stress, Endothelial Dysfunction And Enhanced Thromboxane And Endothelin Contractility That Are Prevented By Spironolactone.

Introduction and hypothesis: Following bodily entry, the SARS-CoV-2 virus undergoes pulmonary replication with release of circulating viral spike protein 1 (SP1) into the bloodstream. Uptake of SP1 by endothelial cells might provoke vascular dysfunction and thrombosis. We hypothesized that spironolactone could prevent microvascular complications from circulating SP1 in COVID-19. Methods: male C57Bl/6 mice received spironolactone (100 mg · kg -1 · d -1 PO x 3d) or vehicle and intravenous injections of recombinant full-length human SP1 (10 μg per mouse) or vehicle. They were euthanized after 3 days. Mesenteric resistant arterioles (n=4 per group) were dissected and mounted on isometric myographs. Acetylcholine-induced EDRF responses and L-NAME-inhibitable NO generation (DAF-FM fluorescence) were studied in pre-constricted vessels and contraction to endothelin 1 (ET1) or thromboxane (U-46, 619) and ET1-induced ROS (PEG-SOD inhibitable ethidium: dihydroethidium fluorescence) were studied by fluorescence microscopy in other vessels. Results: SP1 reduced acetylcholine-induced EDRF (17 ± 3 vs 27 ± 5 % mean ± sem; P < 0.05) and NO generation (0.21 ± 0.03 vs 0.36 ± 0.04, F 1 /F 0 ; P < 0.05) while increasing contraction to ET1 (10 -7 mol·l -1 : 124 ± 13 vs 89 ± 4 %; P < 0.05) and U-46, 619 (10 -6 mol·l -1 :114± 5 vs 87± 6 %; P < 0.05) and ET1-induced ROS generation(0.30± 0.08 vs 0.09± 0.03; P < 0.05). Spironolactone did not modify any of these responses in vessels from normal mice but prevented all the effects of SP1. Conclusion: these preliminary studies provide a novel model to study COVID-19 vasculopathy. They indicate that spironolactone can provide protection from microvascular oxidative stress, endothelial dysfunction and enhanced contractility and might thereby moderate COVID-19 complications.