APOE (Apolipoprotein E): APOE, a protein primarily synthesized by the liver and astrocytes in the brain, is crucial for lipid metabolism and transport, particularly in the central nervous system (CNS). It plays a significant role in the clearance of lipoproteins from circulation and the redistribution of cholesterol and other lipids to cells via interactions with cell surface receptors. APOE exists in three common isoforms—APOE2, APOE3, and APOE4—each encoded by a different allele of the APOE gene. These isoforms differ in their affinity for lipoprotein receptors and their subsequent impact on lipid metabolism. APOE4, in particular, has been extensively studied due...