Apolipoprotein E is a key regulator of lipoprotein metabolism. It plays a multi-functional role by potentially acting as a cofactor in very low-density lipoprotein (VLDL) synthesis, the hydrolysis of VLDL remnants to produce low-density lipoprotein (LDL), and as a high-affinity ligand for the receptor-mediated cellular removal of lipoprotein remnants. APOE plays an essential role in triglyceride (TG) metabolism by regulating the clearance of TG-rich lipoproteins such as VLDL and chylomicrons.
The APOE polymorphisms have been shown to impact blood lipid levels, biomarkers of oxidative stress and chronic inflammation. Beyond lipid and cholesterol metabolism, APOE also modulates aspects of ageing in the brain and artery walls.