title: Variation in protein levels obtained from human blood cells and biofluids for platelet, peripheral blood mononuclear cell, plasma, urine and saliva proteomics.
abstract: Blood cells and biofluid proteomics are emerging as a valuable tool to assess effects of interventions on health and disease. This study is aimed to assess the amount and variability of proteins from platelets, peripheral blood mononuclear cells (PBMC), plasma, urine and saliva from ten healthy volunteers for proteomics analysis, and whether protein yield is affected by prolonged fasting. Volunteers provided blood, saliva and morning urine samples once a week for 4 weeks after an overnight fast. Volunteers were fasted for a further 24 h after the fourth sampling before providing their final samples. Each 10 mL whole blood provided 400-1,500 mug protein from platelets, and 100-600 mug from PBMC. 30 muL plasma depleted of albumin and IgG provided 350-650 mug protein. A sample of morning urine provided 0.9-8.6 mg protein/dL, and a sample of saliva provided 70-950 mug protein/mL. None of these yields were influenced by the degree of fasting (overnight or 36 h). In conclusion, in contrast to the yields from plasma, platelets and PBMC, the protein yields of urine and saliva samples were highly variable within and between subjects. Certain disease conditions may cause higher or lower PBMC counts and thus protein yields, or increased urinary protein levels.
authors.affiliation: Rowett Institute of Nutrition and Health, University of Aberdeen, Greenburn Road, Bucksburn, Aberdeen, AB51 7HJ, UK.
authors.forename: L Katie
authors.initials: LK
authors.lastname: Crosley
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Duthie
authors.forename: Abigael C
authors.initials: AC
authors.lastname: Polley
authors.forename: Freek G
authors.initials: FG
authors.lastname: Bouwman
authors.forename: Carolin
authors.initials: C
authors.lastname: Heim
authors.forename: Francis
authors.initials: F
authors.lastname: Mulholland
authors.forename: Graham
authors.initials: G
authors.lastname: Horgan
authors.forename: Ian T
authors.initials: IT
authors.lastname: Johnson
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Mariman
authors.forename: Ruan M
authors.initials: RM
authors.lastname: Elliott
authors.forename: Hannelore
authors.initials: H
authors.lastname: Daniel
authors.forename: Baukje
authors.initials: B
authors.lastname: de Roos