The loss of ACE2 expression results in a severe acute respiratory disease due to the loss of its protective factor increasing damage to the parenchyma and pulmonary edema (73, 74, 78, 89, 92), worsening oxygenation and increasing the formation of hyaline membrane and infiltration of inflammatory cells due to deregulation of the pulmonary renin-angiotensin system (RAS) where Ang II is upregulated after the downregulation of ACE2 (64, 74); this apparently occurs without alterations in cardiac contractility or in the tone of the pulmonary vasculature (78). Here, ACE2 is linked to respiratory system disorder.