Plasma amyloid assay as a pre-screening tool for amyloid positron emission tomography imaging in early stage Alzheimer's disease.

ABSTRACT: INTRODUCTION:Due to the high cost and high failure rate of ascertaining amyloid positron emission tomography positivity (PET+) in patients with earlier stage Alzheimer's disease (AD), an effective pre-screening tool for amyloid PET scans is needed. METHODS:Patients with mild cognitive impairment (n?=?33, 24.2% PET+, 42% females, age 74.4?±?7.5, MMSE 26.8?±?1.9) and mild dementia (n?=?19, 63.6% PET+, 36.3% females, age 73.0?±?9.3, MMSE 22.6?±?2.0) were recruited. Amyloid PET imaging, Apolipoprotein E (APOE) genotyping, and plasma amyloid ? (A?)1-40, A?1-42, and total tau protein quantification by immunomagnetic reduction (IMR) method were performed. Receiver operating characteristics (ROC) analysis and Youden's index were performed to identify possible cut-off points, clinical sensitivities/specificities, and areas under the curve (AUCs). RESULTS:Amyloid PET+ participants had lower plasma A?1-42 levels than amyloid PET-negative (PET-) subjects. APOE ?4 carriers had higher plasma A?1-42 than non-carriers. We developed an algorithm involving the combination of plasma A?1-42 and APOE genotyping. The success rate for detecting amyloid PET+ patients effectively increased from 42.3 to 70.4% among clinically suspected MCI and mild dementia patients. CONCLUSIONS:Our results demonstrate the possibility of utilizing APOE genotypes in combination with plasma A?1-42 levels as a pre-screening tool for predicting the positivity of amyloid PET findings in early stage dementia patients.

SUBMITTER: Lin SY 

PROVIDER: S-EPMC6933740 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature