A recent study by Schweitzer et al (2021) demonstrated increased transcription rate of angiotensin converting enzyme 2 (ACE2) in patients infected with Influenza A virus (IAV). ACE2 is part of the renin-angiotensin-aldosterone system is part of the pathway responsible for mediating hypertension, or elevated blood pressure. During the study, it was found that epithelial cells found in the small airways infected by IAV increased ACE2 expression by eight-fold. ACE2 mediates the cleavage of the angiotensin protein to angiotensin II, which ultimately results in increased systemic vascular resistance and increased sodium and water retention in the kidneys. Activation of this system is detrimental in maintaining normal blood pressure who have already longstanding chronic hypertension, as well as other co-morbidities (including diabetets, heart failure and arterial disease).
Patients infected with SARS-CoV-2 virus resulting in the high transmissible COVID-19 disease, are found to be at a greater rate of co-infection with the IAV. Hence it is clinically important to consider a treatment plan not only specific to the disease, but the systemic side-effects which may eventuate.
Link to the article: https://erj.ersjournals.com/content/58/1/2003988
References:
Kelly S. Schweitzer, Taylor Crue, Jordan M. Nall, Daniel Foster, Satria Sajuthi, Kelly A. Correll, Mari Nakamura, Jamie L. Everman, Gregory P. Downey, Max A. Seibold, James P. Bridges, Karina A. Serban, Hong Wei Chu, Irina Petrache (2021). Influenza virus infection increases ACE2 expression and shedding in human small airway epithelial cells. European Respiratory Journal, 58(1). Doi: 10.1183/13993003.03988-2020.
