Efficacy of Captopril in Covid-19 Patients With Severe Acute Respiratory Syndrome (SARS) CoV-2 Pneumonia (CAPTOCOVID)

Coronavirus Disease 2019 (COVID-19) is due to SARS-CoV-2 infection. The main cause of death is refractory acute respiratory distress syndrome (ARDS) secondary to SARS-CoV-2 pneumonia. The SARS-CoV-2 may have specific virulence factors to achieve mortality rates around 3%. As the SARS-CoV, virus responsible of the Severe Acute Respiratory Syndrome in 2003 (which mortality was around 10%), the SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) as the receptor binding domain for its spike protein making ACE2 the gateway in the alveolar epithelial cells1. Angiotensin-converting enzyme (ACE) and ACE2 are known to be present in respiratory epithelium and to have antagonist physiological functions. ACE2 has an anti-inflammatory, anti-fibrosing role, anti-oxydant and vasodilatator activity, while ACE has the opposite characteristics. These two enzymes have a negative control on each other, one inhibiting the other. Demonstrated that SARS-CoV is responsible of a downregulation of ACE2 functions by using ACE2 as cell receptor2. While ACE2 is downregulated, ACE activity increase leading to more alveolar damage and acute respiratory failure. ACE inhibitors are common drugs used to treat hypertension worldwide. Using an ACE inhibitor as treatment against SARS-CoV-2 could be counter-intuitive because increasing ACE2 expression would open the cellular gate to the virus3,4. However, ACE2 was described as protecting lung injury2, leading Recombinant Human ACE2 as a perspective for SARS-CoV-2 treatment. A simple way to increase ACE2 in patients with SARS-CoV-2 pneumonia could be an inhalation of ACE inhibitor.