title: Effects of storage time and exogenous protease inhibitors on plasma protein levels.
abstract: Plasma biomarker analysis requires intact unbiased starting material. We analyzed the effects on plasma protein profiles of protease inhibitor cocktails and preprocessing storage. Plasma from 12 healthy subjects collected with and without protease inhibitors was prepared immediately and after 2 hours of room temperature storage. The samples were analyzed by a multiplexed enzyme-linked immunosorbent assay that captured 99 chemokines and cytokines. Unsupervised hierarchical analysis clustered the samples into 4 groups; one composed predominantly of samples processed immediately, another of samples processed after 2 hours, and the remaining two were a mix of immediate and 2-hour samples. The mixed and immediate group protein profiles were similar. However, among the immediate and 2-hour samples, the levels of 37 factors differed significantly: all were greater after 2 hours. The dramatic changes in protein levels during storage were independent of protease inhibitors and are likely due to cytokine production and/or release by leukocytes and platelets.
authors.affiliation: Immunogenetics Laboratory, Department of Transfusion Medicine, Warren G. Magnuson Clinical Center National Institutes of Health, Bethesda, MD 20892-1184, USA.
authors.forename: Saleh
authors.initials: S
authors.lastname: Ayache
authors.forename: Monica
authors.initials: M
authors.lastname: Panelli
authors.forename: Francesco M
authors.initials: FM
authors.lastname: Marincola
authors.forename: David F
authors.initials: DF
authors.lastname: Stroncek
mesh_terms: D001793:Blood Preservation / Q000379:methods*; D001798:Blood Proteins / Q000032:analysis* / Q000378:metabolism; D001800:Blood Specimen Collection / Q000379:methods*; D016000:Cluster Analysis; D015925:Cryopreservation; D016207:Cytokines / Q000032:analysis / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007091:Image Processing, Computer-Assisted; D010447:Peptide Hydrolases / Q000378:metabolism; D011480:Protease Inhibitors / Q000737:chemistry* / Q000378:metabolism; D040901:Proteomics; D013997:Time Factors
chemical_list: D001798:Blood Proteins; D016207:Cytokines; D011480:Protease Inhibitors; D010447:Peptide Hydrolases