Renin-Angiotensin System Inhibitors and COVID-19 (SARS-RAS)

The recent SARS-CoV-2 Coronavirus pandemic and subsequent spread of the disease called COVID-19 brought back to the discussion a topic already highlighted during the SARS-CoV-4 crown-related SARS epidemic of 2002. In particular, the angiotensin converting enzyme 2 (ACE2) has been identified as a functional receptor for coronaviruses, therefore including SARS-CoV-2. ACE2 is strongly expressed in the heart and lungs. SARS-CoV-2 mainly invades alveolar epithelial cells, resulting in respiratory symptoms. These symptoms could be made more severe in the presence of increased expression of ACE2. ACE2 levels can be increased by the use of renin-angiotensin system inhibitors (RAS). This therapeutic class is particularly widespread, as it represents the most important pharmacological protection for widespread diseases such as high blood pressure, heart failure and ischemic heart disease. It is therefore possible to hypothesize that pharmacological treatment with RAS inhibitors may be associated with a more severe symptomatology and clinic than COVID-19.

However, several observations from studies on SARSCoV, which are most likely also relevant for SARS-CoV-2 seem to suggest otherwise. Indeed, it has been shown that the binding of coronavirus to ACE2 leads to downregulation of ACE2, which in turn causes an ACE / ACE2 imbalance excessive production of angiotensin by the related ACE enzyme. Angiotensin II receptor 1 (AT1R) stimulated by angiotensin causes an increase in pulmonary vascular permeability, thereby mediating an increase in lung damage. Therefore, according to this hypothesis, the upregulation of ACE2, caused by the chronic intake of AT1R and ACE Inhibitors, could be protective through two mechanisms: the first, that of blocking in the AT1 receptor; second, increasing ACE2 levels decreases ACE production of angiotensin and increases ACE2 production of angiotensin 1-7.

The quickest approach to evaluating these two opposing hypotheses is to analyze the medical records of COVID-19 patients to determine whether patients on RAS antagonist therapy have a different disease outcome than patients without the above therapy.

This research aims to verify whether the chronic intake of RAS inhibitors modifies the prevalence and severity of the clinical manifestation of COVID-19.