Kallikrein-kinin blockade in patients with covid-19 to prevent acute respiratory distress syndrome

COVID-19 patients can present with pulmonary edema early in disease. We propose that the this is due to a local vascular problem because of activation of bradykinin 1 receptor (B1R) and B2R on endothelial cells in the lungs. SARS-CoV-2 enters the cell via ACE2 that next to its role in RAS is needed to inactivate des-Arg9 bradykinin, the potent ligand of the bradykinin receptor type 1 (B1). Without ACE2 acting as a guardian to inactivate the ligands of B1, the lung environment is prone for local vascular leakage leading to angioedema. Here we hypothesize that a bradykinin-dependent local lung angioedema via B1 and B2 receptors is an important feature of COVID-19. We propose that blocking the B2 receptor and inhibiting kallikrein activity might have an ameliorating effect on early disease caused by COVID-19 and might prevent acute respiratory distress syndrome (ARDS). In addition, this pathway might indirectly be responsive to anti-inflammatory agents.