ACE2 and COVID-19: To further investigate this, we therefore examined the therapeutic effect of Reg on COVID‐19 by employing K18‐hACE2 transgenic mice (hACE2 mice) that overexpress human angiotensin‐converting enzyme 2 (ACE2) receptors driven by cytokeratin‐18 (K18) gene promoters, a cellular entry point of the SARS‐CoV‐2 virus [11, 12].