A new methodology for simultaneous quantification of total-Aβ, Aβx-38, Aβx-40, and Aβx-42 by column-switching LC/MS/MS

• Published in: Analytical and bioanalytical chemistry Vol. 402; no. 6; pp. 2033 - 2042
• Main Authors: Watanabe, Ken-ichi, Ishikawa, Chihiro, Kuwahara, Hiroshi, Sato, Kimihiko, Komuro, Setsuko, Nakagawa, Tetsuya, Nomura, Naruaki, Watanabe, Shiro, Yabuki, Masashi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2012
• Subjects: Amino Acid Sequence; Amyloid beta-Peptides - analysis; Analytical Chemistry; Animals; Anti-Inflammatory Agents, Non-Steroidal - pharmacology; Biochemistry; Brain; Brain - drug effects; Brain - metabolism; Calibration; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chromatography, Liquid - methods; Flurbiprofen - pharmacology; Food Science; Laboratory Medicine; Liquids; Male; Mathematical analysis; Molecular Sequence Data; Monitoring/Environmental Analysis; Original Paper; Purification; Rats; Rats, Sprague-Dawley; Reproducibility; Reproducibility of Results; Standard deviation; Tandem Mass Spectrometry - methods; Biomarker; Quantification; Total-Aβ, Aβx-38, Aβx-40, and Aβx-42; Column-switching LC/MS/MS; Rat brain
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-011-5648-1

This article details the development of a novel method that overcomes the drawbacks of sandwich ELISA (sELISA) and allows reliable evaluation of simultaneous quantification of the amyloid (Aβ)-peptides, total-Aβ, Aβx-38, Aβx-40, and Aβx-42, in rat brain by optimized sample purification and column-switching liquid chromatographic-tandem mass spectrometry (LC/MS/MS). This method provides accurate analyses of total-Aβ, Aβx-38, Aβx-40, and Aβx-42 with a linear calibration range between 0.05 and 45 ng/mL. Verification for accuracy and precision of biological samples were determined by a standard addition and recovery test, spiked with synthetic Aβ1-38, Aβ1-40, and Aβ1-42 into the rat brain homogenate. This method showed <20% relative error and relative standard deviation, indicating high reproducibility and reliability. The brain concentrations of total-Aβ, Aβx-38, Aβx-40, and Aβx-42 after oral administration of flurbiprofen in rats were measured by this method. Aβx-42 concentrations (4.57 ± 0.69 ng/g) in rats administered flurbiprofen were lower than those in untreated rats (6.48 ± 0.93 ng/g). This was consistent with several reports demonstrating that NSAIDs reduced the generation of Aβ. We report here a method that allows not only the quantification of specific molecular species of Aβ but also simultaneous quantification of total-Aβ, Aβx-38, Aβx-40, and Aβx-42, thus overcoming the drawbacks of sELISA.