Changes in Aβ biomarkers and associations with APOE genotype in 2 longitudinal cohorts
Neurobiology of Aging
(maximum allowed 170) Number of Words in Text: 3,470 ABSTRACT Apolipoprotein E (APOE) genotype influences onset age of Alzheimer's disease but effects on disease progression are less clear. We investigated amyloid-β (Aβ) levels and change in relationship to APOE genotype, using two different measures of Aβ in two different longitudinal cohorts. Aβ accumulation was measured using PET imaging and 11 C-Pittsburgh compound-B (PiB) in 113 Baltimore Longitudinal Study of Aging (BLSA) participants
... n age 77.3 years; 107 normal, 6 cognitively impaired) and CSF Aβ 1-42 assays in 207 BIOCARD study participants (mean age 62 years; 195 normal,12 cognitively impaired). Participants in both cohorts had up to 7 serial assessments (mean 2.3-2.4). PET-PiB retention increased and CSF Aβ 1-42 declined longitudinally. APOE ε4 was significantly associated with higher PET-PiB retention and lower CSF Aβ 1-42, independent of age and sex, but APOE genotype did not significantly affect Aβ change over time. APOE ε4 carriers may be further along in the disease process, consistent with earlier brain Aβ deposition and providing a biological basis for APOE genotype effects on onset age of Alzheimer's disease. longitudinal Institute on Aging and by Research and Development Contract HHSN-260-2004-00012C. We are grateful to the BLSA participants and staff for their dedication to these studies and the staff of the Johns Hopkins PET facility for their assistance. We are especially grateful to Wendy Elkins and Brieana Viscomi for their assistance with coordination and data collection for the PET-PiB studies.