 The human SARS-CoV-2 virus has a receptor on the surface of the virus particle named angiotensin converting enzyme 2, ACE2, that is expressed in the central nervous system and in the adipose tissue. The SARS-CoV-2 genome has the ability to replicate itself by directly binding to the ACE2 receptor on host cells. An ACE2 receptor has a high specificity to specific ACE2 and high expression levels of ACE2 are present in many organs of the human body. There are two major ACE2 receptors in the small intestine, testis, kidneys, heart, thyroid, and adipose tissue. This article was authored by Meng Yuan Li, Lin Li, Yu Zhong, and others.