IS ALZHEIMERS-DISEASE AN APOLIPOPROTEIN-E AMYLOIDOSIS

The presence of the apolipoprotein E4 allele has been identified as a major risk factor for late-onset Alzheimer's disease. Apolipoprotein E has also been found immunohistochemically in Alzheimer's disease lesi ons. We biochemically isolated amyloid beta from senile plaques and fo und that a carboxyl-terminal fragment (residues 216-299) of apolipopro tein E co-purified. In vitro this fragment from recombinant apolipopro tein E could form amyloid-like fibrils, which were Congo-red positive. Thus senile plaques may contain both amyloid beta and apolipoprotein E amyloid fibrils.