Authors: Naoki Kaneko, Ritsuko Yoda, Akihito Korenaga, Yuko Ohashi, Mamoru Honda, Yusaku Hioki, Sadanori Sekiya, Shinichi Iwamoto, Kazushige Tsujino, Koichi Tanaka
Published: 2020-12-07
DOI: 10.1002/alz.045810
Source: Full article
AbstractBackgroundThe measurement of plasma amyloid β recently attracts much attention as a biomarker of Alzheimer’s disease. We developed a highly sensitive method for simultaneous detection of a plurality of amyloid β peptides in human plasma by using immunoprecipitation combined with matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (IP‐MALDI‐MS). In this study, we examined the effects of interfering substances in human plasma to reinforce the performance and practicability of this approach.MethodAnticoagulants, Alzheimer's disease drugs, peptides having the epitope with high homology to 6E10 anti‐amyloid β antibody, and a drug having a similar mass to the amyloid β peptide were added to human plasma. The doped plasmas were then analyzed by IP‐MALDI‐MS. Plasma with PBS added was used as a control.ResultTwo biomarker values (Aβ1‐40/Aβ1‐42 and APP669‐711/Aβ1‐42) in the interfering substances doped plasma were compared to those of control plasma. The results showed that the addition of any of those drugs had only a slight effect on the measured values, and the difference between the plasma biomarkers to which the compound was added was ± 10% or less relative to the control.ConclusionThe analysis of plasma amyloid β biomarkers by IP‐MALDI‐MS is a unique method for the simultaneous detection of multiple amyloid β peptides requiring only one kind of antibody. Addition of twelve kinds of contaminants to the human plasma have limited effects on the analytical performance of the system.