ACE2 and respiratory failure: Broad tropism of SARS-CoV-2 infection has been shown in various tissues, including lung, small intestine, kidney, and pancreas [24,25,26,27]; however, most severe SARS-CoV-2 infections in patients are commonly associated with extensive lung damage that results in pneumonia, acute respiratory failure, and death due to abundant amounts of the SARS-CoV-2 principal receptor, angiotensin-converting enzyme 2 (ACE2) being expressed in the airway epithelium, and the respiratory tract being the first portal of entry [27,28,29,30].