title: The impact of delayed storage on the measured proteome and metabolome of human cerebrospinal fluid.
abstract: BACKGROUND
  Because cerebrospinal fluid (CSF) is in close contact with diseased areas in neurological disorders, it is an important source of material in the search for molecular biomarkers. However, sample handling for CSF collected from patients in a clinical setting might not always be adequate for use in proteomics and metabolomics studies.
  
  
  METHODS
  We left CSF for 0, 30, and 120 min at room temperature immediately after sample collection and centrifugation/removal of cells. At 2 laboratories CSF proteomes were subjected to tryptic digestion and analyzed by use of nano-liquid chromatography (LC) Orbitrap mass spectrometry (MS) and chipLC quadrupole TOF-MS. Metabolome analysis was performed at 3 laboratories by NMR, GC-MS, and LC-MS. Targeted analyses of cystatin C and albumin were performed by LC-tandem MS in the selected reaction monitoring mode.
  
  
  RESULTS
  We did not find significant changes in the measured proteome and metabolome of CSF stored at room temperature after centrifugation, except for 2 peptides and 1 metabolite, 2,3,4-trihydroxybutanoic (threonic) acid, of 5780 identified peptides and 93 identified metabolites. A sensitive protein stability marker, cystatin C, was not affected.
  
  
  CONCLUSIONS
  The measured proteome and metabolome of centrifuged human CSF is stable at room temperature for up to 2 hours. We cannot exclude, however, that changes undetectable with our current methodology, such as denaturation or proteolysis, might occur because of sample handling conditions. The stability we observed gives laboratory personnel at the collection site sufficient time to aliquot samples before freezing and storage at -80 °C.
authors: Analytical Biochemistry, Department of Pharmacy, University of Groningen, Groningen, the Netherlands.
authors: Therese
authors: T
authors: Rosenling
authors: Marcel P
authors: MP
authors: Stoop
authors: Agnieszka
authors: A
authors: Smolinska
authors: Bas
authors: B
authors: Muilwijk
authors: Leon
authors: L
authors: Coulier
authors: Shanna
authors: S
authors: Shi
authors: Adrie
authors: A
authors: Dane
authors: Christin
authors: C
authors: Christin
authors: Frank
authors: F
authors: Suits
authors: Peter L
authors: PL
authors: Horvatovich
authors: Sybren S
authors: SS
authors: Wijmenga
authors: Lutgarde M C
authors: LM
authors: Buydens
authors: Rob
authors: R
authors: Vreeken
authors: Thomas
authors: T
authors: Hankemeier
authors: Alain J
authors: AJ
authors: van Gool
authors: Theo M
authors: TM
authors: Luider
authors: Rainer
authors: R
authors: Bischoff
mesh_terms: D002555:Cerebrospinal Fluid; D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods; D055442:Metabolome; D020543:Proteome / Q000378:metabolism*; D013048:Specimen Handling; D013997:Time Factors
chemical_list: D020543:Proteome