The influence of renin angiotensin aldosterone system (RAAS), endothelial nitric oxide synthase (eNOS) and erythropoietin (EPO) on COVID-19 complications

Certain aspects of the renin-angiotensin-aldosterone system (RAAS) have eluded deserved attention such as the role of erythropoietin (EPO) and nitric oxide (NO) both of which appear to significantly modulate COVID-19 disease course. Furthermore, renin-angiotensin-aldosterone system (RAAS) and endothelial NO synthase (eNOS) genetic polymorphisms additionally impact on EPO and NO homeostasis and have extensive implications on pharmacological disease management. •EPO is regulated not only by hypoxia or anemia but also by RAAS and its genetic polymorphisms.•Endothelial nitric oxide (NO) synthase (eNOS) activity in endothelium mediates EPO effects.•Increased NO-generation and bioavailability inhibits SARS-CoV-2 ACE2 binding.•eNOS genetic variants alter NO-generation and bioavailability and may modulate COVID-19 course.•EPO oversecretion appears protective against SARS-CoV-2 infection in children and young adults.