Tags

Type your tag names separated by a space and hit enter

Quantitative analysis of amyloid beta peptides in cerebrospinal fluid of Alzheimer's disease patients by immunoaffinity purification and stable isotope dilution liquid chromatography/negative electrospray ionization tandem mass spectrometry.
Rapid Commun Mass Spectrom. 2006; 20(24):3723-35.RC

Abstract

The 40 and 42 amino-acid residue forms of amyloid beta (Abeta(1-40) and Abeta(1-42)) in cerebrospinal fluid (CSF) have been proposed as potential biomarkers of Alzheimer's disease (AD). Quantitative analyses of Abeta peptides in CSF have relied almost exclusively on the use of immunoassay-based assays such as the enzyme-linked immunosorbent assay (ELISA) procedure. However, due to the ability of the Abeta peptides to readily self-aggregate or bind to other proteins and glassware, such analyses are extremely challenging. Analyses are further complicated by the potential of the peptides to undergo post-translational modifications and the possibilities for cross-reaction in the ELISA assays with endogenous components of the CSF. An approach based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) has now been developed which overcomes these methodological issues. The key steps in implementing this new approach involved immunoaffinity purification coupled with the use of [15N]-labeled Abeta peptides as internal standards, a basic LC mobile phase, negative ion electrospray ionization, and a basic solvent for dissolving the peptides and washing the injection needle to prevent carryover of analytes during multiple injections on the LC/MS system. The validated method had limits of quantitation of 44 fmol/mL (200 pg/mL) for Abeta(1-42) and 92 fmol/mL (400 pg/mL) for Abeta(1-40). An excellent correlation was found between the LC/MS/MS assay and an ELISA assay for Abeta(1-42) in human CSF (r2 = 0.915), although less correlation was observed for Abeta(1-40) (r2 = 0.644). Mean CSF Abeta(1-42) concentrations for samples collected 2 weeks apart from a limited number of AD patients provided additional confidence in the reproducibility of the LC/MS/MS assay. Concentrations for duplicate samples from AD patients were slightly higher than most previously reported values (mean 1.06 +/- 0.25 ng/mL; n = 7). Abeta(1-40) concentrations in duplicate samples obtained from AD patients were also reproducible but were found to be slightly lower than most previously reported values (mean 6.36 +/- 3.07 ng/mL; n = 7). Consistent with literature reports, mean Abeta(1-42) concentrations were found to be lower in AD patients compared with the normal subjects (mean 1.49 +/- 0.59 ng/mL; n = 7), whereas there was no difference in Abeta(1-40) concentrations between AD patients and normal subjects (mean 5.88 +/- 3.03 ng/mL; n = 7). The accuracy and precision of the LC/MS assay mean that it will be a useful complement to existing ELISA assays for monitoring therapeutic interventions designed to modulate CSF Abeta(1-42) concentrations in individual AD patients. Moreover, the introduction of stable isotope labeled internal standards offers the potential to achieve a more rigorous account of the influence of methodological effects related to sample collection and processing.

Authors+Show Affiliations

Centers for Cancer Pharmacology and Excellence in Environmental Toxicology, Departments of Pharmacology and Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

17117458

Citation

Oe, Tomoyuki, et al. "Quantitative Analysis of Amyloid Beta Peptides in Cerebrospinal Fluid of Alzheimer's Disease Patients By Immunoaffinity Purification and Stable Isotope Dilution Liquid Chromatography/negative Electrospray Ionization Tandem Mass Spectrometry." Rapid Communications in Mass Spectrometry : RCM, vol. 20, no. 24, 2006, pp. 3723-35.
Oe T, Ackermann BL, Inoue K, et al. Quantitative analysis of amyloid beta peptides in cerebrospinal fluid of Alzheimer's disease patients by immunoaffinity purification and stable isotope dilution liquid chromatography/negative electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom. 2006;20(24):3723-35.
Oe, T., Ackermann, B. L., Inoue, K., Berna, M. J., Garner, C. O., Gelfanova, V., Dean, R. A., Siemers, E. R., Holtzman, D. M., Farlow, M. R., & Blair, I. A. (2006). Quantitative analysis of amyloid beta peptides in cerebrospinal fluid of Alzheimer's disease patients by immunoaffinity purification and stable isotope dilution liquid chromatography/negative electrospray ionization tandem mass spectrometry. Rapid Communications in Mass Spectrometry : RCM, 20(24), 3723-35.
Oe T, et al. Quantitative Analysis of Amyloid Beta Peptides in Cerebrospinal Fluid of Alzheimer's Disease Patients By Immunoaffinity Purification and Stable Isotope Dilution Liquid Chromatography/negative Electrospray Ionization Tandem Mass Spectrometry. Rapid Commun Mass Spectrom. 2006;20(24):3723-35. PubMed PMID: 17117458.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Quantitative analysis of amyloid beta peptides in cerebrospinal fluid of Alzheimer's disease patients by immunoaffinity purification and stable isotope dilution liquid chromatography/negative electrospray ionization tandem mass spectrometry. AU - Oe,Tomoyuki, AU - Ackermann,Bradley L, AU - Inoue,Koichi, AU - Berna,Michael J, AU - Garner,Carlos O, AU - Gelfanova,Valentina, AU - Dean,Robert A, AU - Siemers,Eric R, AU - Holtzman,David M, AU - Farlow,Martin R, AU - Blair,Ian A, PY - 2006/11/23/pubmed PY - 2007/1/31/medline PY - 2006/11/23/entrez SP - 3723 EP - 35 JF - Rapid communications in mass spectrometry : RCM JO - Rapid Commun Mass Spectrom VL - 20 IS - 24 N2 - The 40 and 42 amino-acid residue forms of amyloid beta (Abeta(1-40) and Abeta(1-42)) in cerebrospinal fluid (CSF) have been proposed as potential biomarkers of Alzheimer's disease (AD). Quantitative analyses of Abeta peptides in CSF have relied almost exclusively on the use of immunoassay-based assays such as the enzyme-linked immunosorbent assay (ELISA) procedure. However, due to the ability of the Abeta peptides to readily self-aggregate or bind to other proteins and glassware, such analyses are extremely challenging. Analyses are further complicated by the potential of the peptides to undergo post-translational modifications and the possibilities for cross-reaction in the ELISA assays with endogenous components of the CSF. An approach based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) has now been developed which overcomes these methodological issues. The key steps in implementing this new approach involved immunoaffinity purification coupled with the use of [15N]-labeled Abeta peptides as internal standards, a basic LC mobile phase, negative ion electrospray ionization, and a basic solvent for dissolving the peptides and washing the injection needle to prevent carryover of analytes during multiple injections on the LC/MS system. The validated method had limits of quantitation of 44 fmol/mL (200 pg/mL) for Abeta(1-42) and 92 fmol/mL (400 pg/mL) for Abeta(1-40). An excellent correlation was found between the LC/MS/MS assay and an ELISA assay for Abeta(1-42) in human CSF (r2 = 0.915), although less correlation was observed for Abeta(1-40) (r2 = 0.644). Mean CSF Abeta(1-42) concentrations for samples collected 2 weeks apart from a limited number of AD patients provided additional confidence in the reproducibility of the LC/MS/MS assay. Concentrations for duplicate samples from AD patients were slightly higher than most previously reported values (mean 1.06 +/- 0.25 ng/mL; n = 7). Abeta(1-40) concentrations in duplicate samples obtained from AD patients were also reproducible but were found to be slightly lower than most previously reported values (mean 6.36 +/- 3.07 ng/mL; n = 7). Consistent with literature reports, mean Abeta(1-42) concentrations were found to be lower in AD patients compared with the normal subjects (mean 1.49 +/- 0.59 ng/mL; n = 7), whereas there was no difference in Abeta(1-40) concentrations between AD patients and normal subjects (mean 5.88 +/- 3.03 ng/mL; n = 7). The accuracy and precision of the LC/MS assay mean that it will be a useful complement to existing ELISA assays for monitoring therapeutic interventions designed to modulate CSF Abeta(1-42) concentrations in individual AD patients. Moreover, the introduction of stable isotope labeled internal standards offers the potential to achieve a more rigorous account of the influence of methodological effects related to sample collection and processing. SN - 0951-4198 UR - https://www.unboundmedicine.com/medline/citation/17117458/Quantitative_analysis_of_amyloid_beta_peptides_in_cerebrospinal_fluid_of_Alzheimer's_disease_patients_by_immunoaffinity_purification_and_stable_isotope_dilution_liquid_chromatography/negative_electrospray_ionization_tandem_mass_spectrometry_ L2 - https://doi.org/10.1002/rcm.2787 DB - PRIME DP - Unbound Medicine ER -