Introduction: Cerebrospinal fluid analysis and other measurements of amyloidosis, such as amyloid-binding positron emission tomography studies, are limited by cost and availability. There is a need for a more practical amyloid β (Aβ) biomarker for central nervous system amyloid deposition.
Methods: We adapted our previously reported stable isotope labeling kinetics protocol to analyze the turnover kinetics and concentrations of Aβ38, Aβ40, and Aβ42 in human plasma.
Results: Aβ isoforms have a half-life of approximately 3 hours in plasma. Aβ38 demonstrated faster turnover kinetics compared with Aβ40 and Aβ42. Faster fractional turnover of Aβ42 relative to Aβ40 and lower Aβ42 and Aβ42/Aβ40 concentrations in amyloid-positive participants were observed.
Discussion: Blood plasma Aβ42 shows similar amyloid-associated alterations as we have previously reported in cerebrospinal fluid, suggesting a blood-brain transportation mechanism of Aβ. The stability and sensitivity of plasma Aβ measurements suggest this may be a useful screening test for central nervous system amyloidosis.
Keywords: Amyloid β; Aβ42; Human; Kinetics; Plasma; Turnover.
Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.