The role of ACE-2
ACE-2 is a type I transmembrane metallocarboxyptidase with ACE homology which is an enzyme known to be a key player in the renin-angiotensin system (RAS) and a target of several drugs for the treatment of high blood pressure. The expression of ACE and ACE-2 is not similar in human tissue. ACE-2 is mainly expressed in vascular endothelial cells, renal tubular epithelium, Leydig cells in the testicles and lung epithelial cells. ACE-2 is a functional receptor of SARS-CoV and SARS-Cov-2 for entry into host cells and subsequent viral replication. Viral entry into respiratory tract cells is a critical step that causes lung injury. Men are thought to be at greater risk of contracting the virus than women because there is a high concentration of ACE-2 in Leydig cells. However, the role of ACE-2 in the pathophysiology of SARS-Cov-2 infection is much more complex than described, since ACE-2 is not only the receptor of the virus entry, in fact the function of ACE-2 in infected lung tissue is currently not very clear, especially in the two most serious stages such as the second and third. where it seems to have a protective role. These new findings could have a great impact on the development of effective therapies for the virus, or to make appropriate use of drugs already on the market that modulate the RAS system to better manage the infection. An interesting line of research is that of anti-ACE-2 antibodies that could be used to block the binding of SARS-CoV-2 to the receptor. (Figure 1). Another possibility that we describe, is the usefulness that a block upstream of the RAS system could have compared to a block downstream at a specific stage of the infection. (7-8-9)