Dysregulation of angiotensin converting enzyme 2 expression and function in comorbid disease conditions possibly contributes to coronavirus infectious disease 2019 complication severity

ACE2 has emerged as a double agent in the COVID-19 ordeal, as it is both physiologically protective and virally conducive. The identification of ACE2 in as many as 72 tissues suggests that extrapulmonary invasion and damage is likely, which indeed has already been demonstrated by cardiovascular and gastrointestinal symptoms. On the other hand, identifying ACE2 dysregulation in patients with comorbidities may offer insight as to why COVID-19 symptoms are often more severe in these individuals. This may be attributed to a pre-existing proinflammatory state that is further propelled with the cytokine storm induced by SARS-CoV-2 infection or the loss of functional ACE2 expression as a result of viral internalization. Here, we aim to characterize the distribution and role of ACE2 in various organs to highlight the scope of damage that may arise upon SARSCoV- 2 invasion. Furthermore, by examining the disruption of ACE2 in several comorbid diseases, we offer insight into potential causes of increased severity of COVID-19 symptoms in certain individuals.This work was supported by the Medical Practice Plan Grants from the Faculty of Medicine at the American University of Beirut [320148] to A.F.E.-Y. and the Medical Practice Plan Grants from the Faculty of Medicine at the American University of Beirut [320133] to A.H.E. 1S.H. and Z.W. contributed equally to this work. https://doi.org/10.1124/molpharm.120.000119.Scopu