Inhaled and systemic heparin as a repurposed direct antiviral drug for prevention and treatment of COVID-19

Abstract

Here, we advocate a highly favourable opportunity for the treatment of COVID-19 disease by repurposing a long-serving medical agent with an excellent history of clinical use, namely heparin. Heparin is best known as an anticoagulant, but it also exhibits direct antiviral activity against many enveloped viruses and has anti-inflammatory activity. The high incidence of thromboembolic events in COVID-19 patients suggests that coagulopathy plays an important role in the SARS-CoV-2 pathogenesis. This already makes heparin a unique, potentially curative agent that can be used immediately to help resolve the ongoing crisis associated with SARS-CoV-2 infection and COVID-19 disease. We demonstrate here in vitro that heparin does indeed inhibit SARS-CoV-2 infection. The three concurrent modes of activity of heparin (antiviral, anticoagulant and anti-inflammatory) against SARS-CoV-2/COVID-19 form a unique therapeutic combination. Thus, repurposing of heparin to fight SARS-CoV-2 and COVID-19 appears to be a powerful, readily available measure to address the current pandemic.

Keywords: COVID-19; Inhalation; SARS-CoV-2; heparin; pulmonary coagulation.

Fig 1.

Heparin inhibits SARS-CoV-2 plaque formation. a) 800,000 Vero E6 cells were seeded in a 12-well plate the day before infection to result in a 100% confluent cell monolayer. The next day, medium was removed, cells were washed once with PBS and medium containing heparin (Sigma-Aldrich) was added. Cells were then inoculated with SARS-CoV-2 isolate BetaCoV/Netherlands/01/NL/2020 (#010V-03903; European virus archive – global) in 500 μl and incubated for 2 h at 37°C with shaking every 15 to 30 min. Next, cells were overlaid with 1.5 ml of 0.8% Avicel RC-581 (FMC Corporation) in medium containing heparin and incubated for 3 days. Cells were fixed, stained with crystal violet and imaged. b) Virus-induced plaques shown in Fig 1a were counted. c) Cytopathic effect (CPE) was quantified using a custom ImageJ macro as the percentage of non-stained area within one well. Raw images were converted to greyscale, regions of interest (= one well) defined, automatic thresholding (Minimum algorithm) applied and total/white pixel areas calculated. Values represent means of two technical replicates ± sd.