title: Funnel-freezing versus heat-stabilization for the visualization of metabolites by mass spectrometry imaging in a mouse stroke model.
abstract: Tissue preparation is the key to a successful matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) experiment. Rapid post-mortem changes contribute a significant challenge to the use of MSI approaches for the analysis of peptides and metabolites. In this technical note we aimed to compare the tissue fixation method ex-vivo heat-stabilization with in-situ funnel-freezing in a middle cerebral artery occlusion (MCAo) mouse model of stroke, which causes profound alterations in metabolite concentrations. The influence of the duration of the thaw-mounting of the tissue sections on metabolite stability was also determined. We demonstrate improved stability and biomolecule visualization when funnel-freezing was used to sacrifice the mouse compared with heat-stabilization. Results were further improved when funnel-freezing was combined with fast thaw-mounting of the brain sections.
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Inge A
authors.initials: IA
authors.lastname: Mulder
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Clara
authors.initials: C
authors.lastname: Esteve
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Marieke J H
authors.initials: MJ
authors.lastname: Wermer
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.|Percuros BV, Enschede, The Netherlands.|In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Hoehn
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.|Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Else A
authors.initials: EA
authors.lastname: Tolner
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.|Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arn M J M
authors.initials: AM
authors.lastname: van den Maagdenberg
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.|Fondazione Pisana per la Scienza ONLUS, Pisa, Italy.
authors.forename: Liam A
authors.initials: LA
authors.lastname: McDonnell
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D005615:Freezing; D006358:Hot Temperature; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology; D051379:Mice; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: Funnel-freezing; Heat-stabilization; Ischemic stroke; MALDI-MSI; Metabolites; Technology