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Unfractionated heparin inhibits live wild type SARS-CoV-2 cell infectivity at therapeutically relevant concentrations.

Tree, JA; Turnbull, JE; Buttigieg, KR; Elmore, MJ; Coombes, N; Hogwood, J; Mycroft-West, CJ; Andrade De Lima, M; Skidmore, M; Karlsson, R; Chen, Y-H; Yang, Z; Spalluto, CM; Staples, KJ; Yates, EA; Gray, E; Singh, D; Wilkinson, T; Page, CP; Carroll, MW

Unfractionated heparin inhibits live wild type SARS-CoV-2 cell infectivity at therapeutically relevant concentrations. Thumbnail


JA Tree

KR Buttigieg

MJ Elmore

N Coombes

J Hogwood

CJ Mycroft-West

R Karlsson

Y-H Chen

Z Yang

CM Spalluto

KJ Staples

EA Yates

E Gray

D Singh

T Wilkinson

CP Page

MW Carroll


BACKGROUND AND PURPOSE: Currently, there are no licensed vaccines and limited antivirals for the treatment of COVID-19. Heparin (delivered systemically) is currently used to treat anticoagulant anomalies in COVID-19 patients. Additionally, in the United Kingdom, Brazil and Australia, nebulised unfractionated heparin (UFH) is being trialled in COVID-19 patients as a potential treatment. A systematic comparison of the potential antiviral effect of various heparin preparations on live wild type SARS-CoV-2, in vitro, is needed. EXPERIMENTAL APPROACH: Seven different heparin preparations including UFH and low MW heparins (LMWH) of porcine or bovine origin were screened for antiviral activity against live SARS-CoV-2 (Australia/VIC01/2020) using a plaque inhibition assay with Vero E6 cells. Interaction of heparin with spike protein RBD was studied using differential scanning fluorimetry and the inhibition of RBD binding to human ACE2 protein using elisa assays was examined. KEY RESULTS: All the UFH preparations had potent antiviral effects, with IC50 values ranging between 25 and 41 μg·ml-1 , whereas LMWHs were less inhibitory by ~150-fold (IC50 range 3.4-7.8 mg·ml-1 ). Mechanistically, we observed that heparin binds and destabilizes the RBD protein and furthermore, we show heparin directly inhibits the binding of RBD to the human ACE2 protein receptor. CONCLUSION AND IMPLICATIONS: This comparison of clinically relevant heparins shows that UFH has significantly stronger SARS-CoV-2 antiviral activity compared to LMWHs. UFH acts to directly inhibit binding of spike protein to the human ACE2 protein receptor. Overall, the data strongly support further clinical investigation of UFH as a potential treatment for patients with COVID-19.

Journal Article Type Article
Acceptance Date Oct 18, 2020
Publication Date Feb 1, 2021
Journal British Journal of Pharmacology
Print ISSN 0007-1188
Electronic ISSN 1476-5381
Publisher Wiley
Volume 178
Pages 626--635
Keywords COVID-19, LMWH, SARS-CoV-2, UFH, heparin, nebulised, Angiotensin-Converting Enzyme 2, Animals, Antiviral Agents, Chlorocebus aethiops, Heparin, Heparin, Low-Molecular-Weight, Protein Binding, SARS-CoV-2, Spike Glycoprotein, Coronavirus, Viral Plaque Assay
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