APOLIPOPROTEIN-E IS PRESENT IN HIPPOCAMPAL-NEURONS WITHOUT NEUROFIBRILLARY TANGLES IN ALZHEIMERS-DISEASE AND IN AGE-MATCHED CONTROLS

Apolipoprotein E (apoE, protein; APOE, gene) is a susceptibility gene for late-onset familial and sporadic Alzheimer's disease (AD). To exam ine the role of apoE in the pathogenesis of AD, we used immunocytochem istry to compare apoE localization in the hippocampus of histologicall y confirmed cases of AD, Parkinson's disease (PD), and normal controls . We confirmed apoE immunoreactivity in astrocytes, senile plaques, bl ood vessels, and some neurons containing neurofibrillary tangles (NFTs ). In addition, we observed apoE immunoreactivity in hippocampal neuro ns without NFTs in AD and PD patients as well as in some nondemented a ged controls. In AD cases, apoE-immunoreactive neurites were closely a ssociated with beta-amyloid (A beta) containing senile plaques and int raneuronal apoE was sometimes associated with immunoreactive tau prote in accumulation. Thus, apoE is localized where it may affect the biolo gical expression of two characteristic AD pathological correlates: ext racellular A beta deposition and intraneuronal tau metabolism and NFT formation. (C) 1994 Academic Press, Inc.