Early shedding of membrane-bounded ACE2 could be an indicator for disease severity in SARS-CoV-2

SARS-CoV-2 uses membrane bound Angiotensin-Converting Enzyme 2 (ACE2) as a key host receptor for its entry. However, inconsistent results are available in terms of shedding of membrane ACE2 and circulating levels of soluble ACE2 during SARS-CoV-2. To ascertain soluble ACE2 as an effective biomarker for the prediction of COVID-19 outcome, in the present study, we investigated the levels of plasma ACE2 during the early phase of infection in COVID-19 patients. The study involved a total of 42 COVID-19 patients along with 10 healthy controls. Plasma levels of ACE2 was determined using ELISA at the time of admission and on day 7 post admission. The association of sACE2 with D-dimer a marker for hyper-coagulation was performed using a dependence test. Compared to healthy controls, SARS-CoV-2 cases has shown a huge increase in the sACE2 at the time of admission. During the course of infection, we found a significant increase (P ≤ 0.001) in sACE2 in severe cases compared to moderate. There was a strong increase in sACE2 in cases with hypertension and diabetes mellitus. Interestingly, a strong positive correlation (P ≤ 0.001) was obtained between sACE2 and D-dimer. Thus, an excessive shedding of ACE2 during the early phase is a common phenomenon in severe form of the SARS-CoV-2. Along with D-dimer, the sACE2 levels could serve as a clinical biomarker for the prediction of disease outcome. However further studies are needed to ascertain its role in host-virus interplay.