In the central nervous system (CNS), essentially all (99.5%) cholesterol is unesterified, and the majority of cholesterol present in the CNS is believed to reside in two different areas:
- The myelin sheaths that protect the nerve cells
- The cell membranes of astrocytes and neuron
It has been estimated that up to 70% of the brain cholesterol is associated with myelin. Myelin is the protective coating around nerve cells and aides in electrical conduction.
Brain is the most cholesterol-rich organ in the body
The concentration of cholesterol in the brain, particularly in myelin, is consistent with its essential function related to membrane activity. The cell membrane is critical for health and survival.