ACE2 and obesity due to melanocortin 4 receptor deficiency: To clarify this issue, particularly in the lung, we recently studied the effects of the ARB candesartan and the ACEI captopril on lung levels of ACE2 and other major RAS components in adult healthy rats, and in aged rats and rats with metabolic syndrome (obesity, increased blood pressure, hyperglycemia) as animal models of individuals particularly vulnerable to severe COVID-19 [32].