Plasma amyloid-beta as a biomarker in Alzheimer's disease: the AIBL study of aging.
Amyloid-beta (Abeta) plays a central role in the pathogenesis of Alzheimer's disease (AD) and has been postulated as a potential biomarker for AD. However, there is a lack of consensus as to its suitability as an AD biomarker. The objective of this study was to determine the significance of plasma Abeta as an AD biomarker and its relationship with Abeta load and to determine the effect of different assay methods on the interpretation of Abeta levels. Plasma Abeta1-40, Abeta1-42, and N-terminal cleaved fragments were measured using both a commercial multiplex assay and a well-documented ELISA in 1032 individuals drawn from the well-characterized Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging. Further, Abeta levels were compared to Abeta load derived from positron-emission tomography (PET) with the Pittsburgh compound B (PiB). Lower Abeta1-42 and Abeta1-42/1-40 ratio were observed in patients with AD and inversely correlated with PiB-PET derived Abeta load. However, assay methodology significantly impacted the interpretation of data. The cross-sectional analysis of plasma Abeta isoforms suggests that they may not be sufficient per se to diagnose AD. The value of their measurement in prognosis and monitoring of AD interventions needs further study, in addition to future longitudinal comparisons together with other predictors, which will determine whether plasma Abeta has diagnostic value in a panel of biomarkers.
Lui
James K
JK
Centre of Excellence for Alzheimer's Disease Research & Care, School of Exercise Biomedical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
Laws
Simon M
SM
Li
Qiao-Xin
QX
Villemagne
Victor L
VL
Ames
David
D
Brown
Belinda
B
Bush
Ashley I
AI
De Ruyck
Karl
K
Dromey
Jasmin
J
Ellis
Kathryn A
KA
Faux
Noel G
NG
Foster
Jonathan
J
Fowler
Christopher
C
Gupta
Veer
V
Hudson
Peter
P
Laughton
Katrina
K
Masters
Colin L
CL
Pertile
Kelly
K
Rembach
Alan
A
Rimajova
Mira
M
Rodrigues
Mark
M
Rowe
Christopher C
CC
Rumble
Rebecca
R
Szoeke
Cassandra
C
Taddei
Kevin
K
Taddei
Tania
T
Trounson
Brett
B
Ward
Vanessa
V
Martins
Ralph N
RN
AIBL Research Group
D000368:Aged; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000097:blood* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000097:blood*; D001057:Apolipoproteins E / Q000378:metabolism; D001315:Australia; D015415:Biomarkers; D001921:Brain / Q000473:pathology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D009483:Neuropsychological Tests; D018570:Risk Assessment; D012959:Socioeconomic Factors
D016229:Amyloid beta-Peptides; D001057:Apolipoproteins E; D015415:Biomarkers