  SARS-CoV-2 coronavirus infection is mediated by the binding of its spike
protein to the angiotensin-converting enzyme 2 (ACE2), which plays a pivotal
role in the renin-angiotensin system (RAS). The study of RAS dysregulation due
to SARS-CoV-2 infection is fundamentally important for a better understanding
of the pathogenic mechanisms and risk factors associated with COVID-19
coronavirus disease, and to design effective therapeutic strategies. In this
context, we developed a mathematical model of RAS based on data regarding
protein and peptide concentrations; the model was tested on clinical data from
healthy normotensive and hypertensive individuals. We then used our model to
analyze the impact of SARS-CoV-2 infection on RAS, which we modeled through a
down-regulation of ACE2 as a function of viral load. We also used it to predict
the effect of RAS-targeting drugs, such as RAS-blockers, human recombinant
ACE2, and angiotensin 1-7 peptide, on COVID-19 patients; the model predicted an
improvement of the clinical outcome for some drugs and a worsening for others.
