Apolipoprotein E (APOE) polymorphism influences serum APOE levels in Alzheimer's disease patients and centenarians.

Vascular factors may play a role in the etiology of Alzheimer’s disease (AD) and increased serum apolipoprotein E (APOE) levels in AD could be of interest, as APOE concentration is associated with vascular disease. Aims of this study were to evaluate the inluence of APOE genotype on serum APOE levels, and, secondly, to study serum APOE concentrations in relation to age and AD. APOE genotypes, serum total cholesterol, LDL cholesterol, HDL cholesterol, total cholesterol/HDL cholesterol ratio, triglycerides, and serum APOE were performed on 52 healthy centenarians, 49 AD patients, 45 age-matched controls, and 72 young healthy adults. In all study population a significant trend in reduction of serum APOE levels from APOE E2- to E4 carriers was observed.The diffeerence in serumAPOE levels amonga ge groups signi¢cantly decreased in E4 carriers only, includingH DL cholesterol; no significant differences between AD patients and age-matched controls were found. In these highly selected populations, APOE genotype distribution strongly influences serum APOE concentration, not suggesting, at present, a possible role as a biochemical marker for AD, but only as a putative longevity factor.