APOLIPOPROTEIN-E IN SPORADIC ALZHEIMERS-DISEASE - ALLELIC VARIATION AND RECEPTOR INTERACTIONS

An increased prevalence of apolipoprotein E (ApoE) epsilon4 allele exi sts in late onset familial Alzheimer's disease. We found, in sporadic Alzheimer's disease, that 62% of patients possessed an ApoE-epsilon4 a llele, compared with 20% of controls. ApoE-epsilon4/4 patients had mor e senile plaques (SPs) than epsilon3/3 patients. ApoE immunoreactivity of SPs was equivalent in both groups. Two receptors bind ApoE complex es, the low density lipoprotein (LDL) receptor and the LDL receptor-re lated protein (LRP). In normal brain, anti-LRP antibodies strongly sta ined neurons and lightly stained astrocytes; anti-LDL receptor antibod ies stained only the neuropil and astrocytes. In Alzheimer's disease, SPs and reactive astrocytes were also strongly LRP immunoreactive. Col ocalization of ApoE and LRP to SPs implies that these molecules may be involved in metabolism of components of SPs.