title: The application of atmospheric pressure matrix-assisted laser desorption/ionization to the analysis of long-term cryopreserved serum peptidome.
abstract: Although most time-of-flight (TOF) mass spectrometers come equipped with vacuum matrix-assisted laser desorption/ionization (MALDI) sources, the atmospheric pressure MALDI (API-MALDI) source is an attractive option because of its ability to be coupled to a wide range of analyzers. This article describes the use of an API-MALDI source coupled to a TOF mass spectrometer for evaluation of the effects of medium- and long-term storage on peptidomic profiles of cryopreserved serum samples from healthy women. Peptides were purified using superparamagnetic beads either from fresh sera or after serum storage at -80°C for 18 months or at -20°C for 8 years. Data were preprocessed using newly developed bioinformatic tools and then were subjected to statistical analysis and class prediction. The analyses showed a dramatic effect of storage on the abundance of several peptides such as fibrinopeptides A and B, complement fractions, bradykinin, and clusterin, indicated by other authors as disease biomarkers. Most of these results were confirmed by shadow clustering analysis, able to classify each sample in the correct group. In addition to demonstrating the suitability of the API-MALDI technique for peptidome profiling studies, our data are of relevance for retrospective studies that involve frozen sera stored for many years in biobanks.
authors.affiliation: SC Oncologia Medica B, Istituto Nazionale per la Ricerca sul Cancro, 16132 Genova, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Mangerini
authors.forename: Paolo
authors.initials: P
authors.lastname: Romano
authors.forename: Angelo
authors.initials: A
authors.lastname: Facchiano
authors.forename: Gianluca
authors.initials: G
authors.lastname: Damonte
authors.forename: Marco
authors.initials: M
authors.lastname: Muselli
authors.forename: Mattia
authors.initials: M
authors.lastname: Rocco
authors.forename: Francesco
authors.initials: F
authors.lastname: Boccardo
authors.forename: Aldo
authors.initials: A
authors.lastname: Profumo
mesh_terms: D001274:Atmospheric Pressure; D001920:Bradykinin / Q000097:blood; D051152:Clusterin / Q000097:blood; D003165:Complement System Proteins / Q000032:analysis; D015925:Cryopreservation; D005260:Female; D005344:Fibrinopeptide A / Q000032:analysis; D005345:Fibrinopeptide B / Q000032:analysis; D006801:Humans; D009369:Neoplasms / Q000097:blood*; D010455:Peptides / Q000097:blood*; D013048:Specimen Handling; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D051152:Clusterin; D010455:Peptides; D005344:Fibrinopeptide A; D005345:Fibrinopeptide B; D003165:Complement System Proteins; D001920:Bradykinin