Coronavirus Disease 2019: The Role of the Fibrinolytic System from Transmission to Organ Injury and Sequelae
Hau C. Kwaan
Abstract
An initial cluster of severe viral pneumonia was discovered in early December 2019 in Wuhan, China. 2] The most notable characteristic of SARS-CoV-2 is its high infectivity. As a result, much attention has been paid to its mode of transmission. The major route of infection is the binding of the spike protein of the virus to its natural receptor angiotensin-converting enzyme (ACE 2) on the surface of the host cells. 2 ACE2 is present in tissues and is particularly abundantly expressed in the lung in the alveolar (type II) cells. This is clinically correlated as the lung is the major organ affected by the viral infection, leading to acute respiratory failure and acute respiratory distress syndrome (ARDS). Many aspects of COVID-19 are similar to those seen in the SARS and in the Middle East respiratory syndrome (MERS), 5,6 including ACE2 being the receptor for the virus. 7 Impaired fibrinolysis was observed in post-SARS complications. 8,9 Impairedfibrinolysis Several possible drug targets that alter the activity of components of the fibrinolytic system are also discussed.