ACE2 and COVID-19: However, unparallel to the many potential targets cells and organs proposed, the COVID-19 patients primarily displayed typical symptoms of inflammation in the lung, where only a very small portion of cells (∼0.64% of total cells and ∼1.4% of AT2 cells) expressed ACE2 mRNA (Zhao et al., 2020); meanwhile, the injuries in other organs/tissues, such as the kidney and the intestinal track, where ACE2 gene was expressed at high levels, seemed to be uncommon (Guan et al., 2020; Wang et al., 2020).