A systematic review of the literature on the relationship between ace2 and sars-cov infection in animal models

Background: similar to the severe acute respiratory syndrome coronavirus (SARS-CoV), research suggests severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) interacts with angiotensin-converting enzyme 2 (ACE2) to gain entry into cells. The primary objective is to synthesize existing animal model research on the association between ACE2 and severe acute respiratory syndrome (SARS) infection. The secondary objective is to describe the consequences of infection on ACE2 expression. Methods: we performed a systematic literature search of Medline, Embase, and Global Health databases. We included animal studies on the connection between SARS-CoV infection and variations in ACE2 receptor or expression thereof. Included studies were assessed for quality using the CAMARADES checklist. Results: we included nine studies, all determining the role of ACE2 in SARS-CoV infections. Five low to moderate quality studies showed that increased ACE2 expression was correlated with increased SARS-CoV infection. Five low to moderate quality studies showed post-infection downregulation of ACE2 to be associated with increased clinical symptoms, morbidity, and mortality. Conclusion: this review shows that pre-infection, greater ACE2 expression correlates with increased infection leading to worse clinical outcomes. Assuming similar mechanisms for SARS-CoV-2 as in SARS-CoV, it is plausible that ACE2 has some role and impact in COVID-19 infections. Further high-quality animal model research is needed to determine the role of ACE2, specifically in COVID-19 infections.