ACE2 and diabetes mellitus: If we consider the disruption of the integrity of the digestive barrier, present during comorbidities associated with severe or critical forms of COVID-19 (diabetes, obesity, and hypertension, as well as other cardiovascular diseases and malignancies), the facilitated access of SARS-CoV-2 virus at ACE2 receptors, as well as changes in the ACE/ACE2 ratio, is understandable.