ABSTRACT
Background. It has been postulated that metformin could have anti-SARS-CoV-2 action. This raises the hypothesis that people who take metformin may have lower SARS-CoV-2 severity and/or mortality. Objectives. To conduct a meta-analysis of the association between the use of Metformin and risk of severity and mortality in SARS-CoV-2 infection. Methods. we searched PubMed, EMbASE, google scholar, the Cochrane Database of Systematic Reviews and preprint servers (medRxiv and Research Square) for studies published between December 2019 and January 2021. Data was extracted on study location, year of publication, design, number of participants, sex, age at baseline, body mass index, and exposure and outcome definition. Effect statistics were pooled using random effects models with 95% confidence intervals (CI). The quality of included studies was assessed with the newcastle-Ottawa Scale (nOS). Results. Thirty-two observational studies were included, combining to a total sample of 44306 participants. The mean nOS score of included studies was 7.9. Results suggested that metformin use was associated with a reduced risk of SARS-CoV-2 mortality (OR = 0.56, 95% CI: 0.46–0.68, P < 0.001;22 studies) but not with disease severity (OR = 0.85, 95% CI: 0.71–1.02, P = 0.077;15 studies). In the subgroup analysis, metformin reduces the risk of mortality (OR = 0.69, 95% CI: 0.55–0.88;P = 0.002) and severity (OR = 0.83, 95% CI: 0.70–0.97, P = 0.023) in patients aged 70 and above. Conclusions. The use of metformin was associated to lower risk of mortality from SARS-CoV-2 infection. This association does not imply causation and further research is required to clarify potential mechanisms. © 2021 Via Medica. All rights reserved.
ABSTRACT
Background: The ongoing SARS-CoV-2 pandemic poses an urgent need to identify novel drug treatments that are effective, well tolerated and quickly translatable to a clinical setting. Methods: In-silico binding modes were predicted by molecular docking. The Bavpat1/2020 SARS-CoV-2 isolate was used to infect Calu-3, T84, Vero E6 cells and a primary colon organoid at MOIs of 0.05 or 0.5. Supernatant and intracellular SARS-CoV-2 RNA was quantified by RT-qPCR or immunofluorescence (IF). The activity of the main protease of SARS-CoV-2 (3CLpro) was measured by FRET assay. Viral protein expression was assessed by western blot. Syncytia formation was determined by IF in cells expressing the spike protein. Cell viability was determined by MTT and crystal violet staining. Synergism scores were calculated using the SynergyFinder web-tool. Results: In-silico docking using a library of FDA-approved drugs highlighted cobicistat as candidate inhibitor of SARS-CoV-2 3CLPro. Experiments using two different viral MOIs in three different cell lines proved that cobicistat inhibits SARS-CoV-2 replication at non-toxic, low micromolar concentrations (IC50 0.6-9μM;CC50 39-52 μM) (Fig 1A). However, cobicistat did not inhibit 3CLpro activity in FRET assay, while western blot analysis suggested that cobicistat impacts on spike glycoprotein levels/processing. Accordingly, cobicistat decreased syncytia formation in spike-expressing Vero E6 cells. The range of in-vitro antiviral concentrations of cobicistat was compatible with plasma levels reachable in mice and humans, but above those achieved through standard dosages used to boost HIV-1 protease inhibitors, in line with the failure of trials testing cobicistat-boosted darunavir on SARS-CoV-2 patients. As the booster activity of cobicistat is exerted through inhibition of Cytochrome P4503A (CYP3A) and P-glycoprotein P-gp (known also as multidrug resistance MDR1), we combined it with remdesivir, which is a putative CYP3A and P-gp substrate. The drug combination was able to synergistically rescue the viability of infected cells to levels comparable to uninfected controls and to almost entirely abrogate viral replication in two cell lines and a primary colon organoid (Figure 1B-D). Conclusion: Cobicistat and remdesivir synergistically inhibit SARS-CoV-2 replication and cytopathic effects. Cobicistat can form the backbone of combination treatments due to its dual activity as direct antiviral and pharmacoenhancer.