ACE and ACE2 activities and polymorphisms assessment: A populational study from Ipaussu (SP, Brazil) during the COVID-19 pandemic.

Aim: The angiotensin-converting enzyme 2 (ACE2) and its homolog, the angiotensin converting enzyme 1 (ACE), are involved in COVID-19 physiopathology. Alterations in the enzymatic structure, expression, and/or activity may influence the risk of infection and severity of disease. For this reason, we aimed to identify different allelic forms of ACE2 G8790A and ACE I/D polymorphisms in a Brazilian cohort and evaluate their impact on ACE and ACE2 activities and their association with COVID-19 susceptibility and severity.

Main Methods: A total of 549 COVID-19-negative and 270 COVID-19-positive participants from Ipaussu, Sao Paulo, Brazil, were recruited. ACE2 and ACE activities were measured by fluorogenic assays using MCA-Ala-Pro-Lys(Dnp) as the substrate for ACE2 and Z-Phe-His-Leu-OH (Z-FHL) and Hippuryl-His-Leu-OH (h-HL) as substrates for ACE. Genomic DNA was extracted from EDTA-peripheral blood, and the regions of the genes containing ACE2 G8790A and ACE I/D polymorphisms were amplified by PCR-restriction fragment length polymorphism and real-time PCR, respectively.

Key Findings: The G allele of ACE2 G8790A polymorphism and D allele of ACE I/D polymorphism are associated with increased ACE and ACE2 activities. ACE activity ratio (Z-FHL/h-HL), an inflammatory marker, is increased in women with GG genotype and COVID-19-positive diagnosis.

Significance: For the first time, it was demonstrated that in females, the GG genotype is associated with increased ACE activity ratio (Z-FHL/h-HL) in the COVID-19-positive group. Elevated ACE activity ratio (Z-FHL/h-HL) is highly linked to inflammation and may justify the associations between the G genotype and COVID-19 severity of symptoms and outcomes.