ACE2 and respiratory failure: SARS-CoV-2 through the angiotensin-converting enzyme 2 (ACE2) binds the epithelial cells in the respiratory tract, then starts replicating and migrating down to the airways, and enters to the alveolar epithelial cells in the lungs (Hu et al., 2021; Rezaei et al., 2021) with the risk of respiratory failure due to the strong immune response induced (Mehta et al., 2020; Ragab et al., 2020).