Introduction: Blood biomarkers of Alzheimer's disease (AD) have attracted much attention of researchers in recent years. In clinical studies, repeated freeze/thaw cycles often occur and may influence the stability of biomarkers. This study aims to investigate the stability of amyloid-β 1-40 (Aβ 1-40 ), amyloid-β 1-42 (Aβ 1-42 ), and total tau protein (T-tau) in plasma over freeze/thaw cycles. Methods: Plasma samples from healthy controls (n = 2), AD patients (AD, n = 3) and Parkinson's disease patients (PD, n = 3) were collected by standardized procedure and immediately frozen at -80 ° C. Samples underwent 5 freeze/thaw (-80 ° C/room temperature) cycles. The concentrations of Aβ 1-40 , Aβ 1-42 , and T-tau were monitored during the freeze/ thaw tests using an immunomagnetic reduction (IMR) assay. The relative percentage of concentrations after every freeze/thaw cycle was calculated for each biomarker. Results: A tendency of decrease in the averaged relative percentages over samples through the freeze and thaw cycles for Aβ 1-40 (100 to 97.11%), Aβ 1-42 (100 to 94.99%), and T-tau (100 to 95.65%) was found. However, the decreases were less than 6%. For all three biomarkers, no statistical significance was found between the levels of fresh plasma and those of the plasma experiencing 5 freeze/thaw cycles (p > 0.1). Conclusions: Plasma Aβ 1-40 , Aβ 1-42 , and T-tau are stable through 5 freeze/thaw cycles measured with IMR.
Introduction Pyroglutamate‐modified amyloid β (AβpE3) could be a biomarker for Aβ plaque pathology in the brain. An ultra‐high‐sensitive assay is needed for detecting AβpE3‐40. Methods Immunomagnetic reduction was used for quantification of AβpE3‐40 in plasma from 46 participants. The concentrations of AβpE3‐40 of these subjects were compared with 18F‐florbetapir positron emission tomography (PET) images. Results AβpE3‐40 concentration was 44.1 ± 28.2 fg/mL in PET‐ (n = 28) and 91.6 ± 54.6 fg/mL in PET+ (n = 18; P < .05). The cutoff value of AβpE3‐40 for discriminating PET‐ from PET+ was 55.5 fg/mL, resulting in a sensitivity of 83.3%, a specificity of 71.4%. The concentration of AβpE3‐40 showed a moderate correlation (r = 0.437) with PET standardized uptake value ratio. Discussion We did not enroll pre‐clinical AD subject with normal cognition but Aβ PET+. It would be an important issue to explore the feasibility of using AβpE3‐40 for screening pre‐clinical subjects. Conclusion These results reveal the feasibility of detecting Aβ pathology using quantification of a plaque‐derived Aβ molecule in plasma.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.