It has been suggested that the transport of 27-hydroxycholesterol from macrophages to the liver for bile acid synthesis is a RCT process to protect against atherosclerosis.[36] CYP27A1 and CYP7B1 are expressed in many extrahepatic tissues, such as the heart, brain, and kidney, and play a key role in the regulation of oxysterol synthesis and steroid hormone synthesis in the adrenal glands.[34]. Here, CYP27A1 is linked to atherosclerosis.