PURPOSE OF REVIEW: The purpose of this review is to provide insights into recent 
advances in mechanisms linking apolipoprotein (apo) E isoforms to cardiovascular 
and neurological diseases.
RECENT FINDINGS: Human apoE has three common isoforms (apoE2, apoE3, and apoE4) 
with different structural and biophysical properties and different effects on 
lipid and neuronal homeostasis. ApoE is a protein constituent of different 
plasma lipoproteins and serves as a high-affinity ligand for several receptors. 
By interacting with its receptors, apoE mediates the clearance of different 
lipoproteins from the circulation. Absence or structural mutations of apoE cause 
significant disorders in lipid metabolism and cardiovascular disease. ApoE also 
has significant roles in neurobiology. ApoE4 is the major known genetic risk 
factor for Alzheimer's disease. It increases the occurrence and lowers the age 
of onset of Alzheimer's disease. ApoE4 carriers account for 65-80% of all 
Alzheimer's disease cases, highlighting the importance of apoE4 in Alzheimer's 
disease pathogenesis. ApoE4 has both amyloid beta-dependent and amyloid 
beta-independent roles in Alzheimer's disease pathogenesis.
SUMMARY: Emerging data suggest that apoE isoforms, with their multiple cellular 
origins and multiple structural and biophysical properties, contribute to 
cardiovascular and neurological diseases by interacting with different factors 
through various pathways.