title: Alterations in Human Liver Metabolome during Prolonged Cryostorage.
abstract: Tissue metabolomics requires high sample quality that crucially depends on the biobanking storage protocol. Hence, we systematically analyzed the influence of realistic storage scenarios on the liver metabolome with different storage temperatures and repeated transfer of samples between storage and retrieval environments, simulating the repeated temperature changes affecting unrelated samples stored in the same container as the sample that is to be retrieved. By cycling between storage (-80 °C freezer, liquid nitrogen, cold nitrogen gas) and retrieval (room temperature, -80 °C), assuming three cycles per day and sample, we simulated biobank storage between 3 months and 10 years. Liver tissue metabolome was analyzed by liquid chromatography/mass spectrometry. Most metabolite concentrations changed <5% for the first "year" of time-compressed biobanking simulation, predominantly due to hydrolysis of peptides and lipids. Interestingly, storage temperature affected metabolite concentrations only little, while there was a linear dependence on the number of temperature change cycles. Elevated sample temperature during (prolonged) retrieval time led to a distinctly different signature of metabolite changes that were induced by cycling. Our findings allow giving recommendations for optimized storage protocols and provide signatures that allow detection of deviations from protocol.
authors.affiliation: †Institute of Pathology, Medical University of Graz, Austria Auenbruggerplatz 25, A-8036 Graz, Austria.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Abuja
authors.affiliation: ‡Fraunhofer Institute of Biomedical Technology, Ensheimer Str. 48, 66386 St. Ingbert, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Ehrhart
authors.affiliation: ‡Fraunhofer Institute of Biomedical Technology, Ensheimer Str. 48, 66386 St. Ingbert, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Schoen
authors.affiliation: ‡Fraunhofer Institute of Biomedical Technology, Ensheimer Str. 48, 66386 St. Ingbert, Germany.
authors.forename: Tomm
authors.initials: T
authors.lastname: Schmidt
authors.affiliation: ‡Fraunhofer Institute of Biomedical Technology, Ensheimer Str. 48, 66386 St. Ingbert, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Stracke
authors.affiliation: §BIOCRATES LifeSciences AG, Eduard-Bodem-Gasse 8, 6020 Innsbruck, Austria.
authors.forename: Guido
authors.initials: G
authors.lastname: Dallmann
authors.affiliation: §BIOCRATES LifeSciences AG, Eduard-Bodem-Gasse 8, 6020 Innsbruck, Austria.
authors.forename: Torben
authors.initials: T
authors.lastname: Friedrich
authors.affiliation: ‡Fraunhofer Institute of Biomedical Technology, Ensheimer Str. 48, 66386 St. Ingbert, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Zimmermann
authors.affiliation: †Institute of Pathology, Medical University of Graz, Austria Auenbruggerplatz 25, A-8036 Graz, Austria.
authors.forename: Kurt
authors.initials: K
authors.lastname: Zatloukal
mesh_terms: D002853:Chromatography, Liquid; D015925:Cryopreservation; D006801:Humans; D008099:Liver / Q000378:metabolism*; D013058:Mass Spectrometry; D055432:Metabolomics
keywords: biobanking; metabolite stability; sample quality; tissue cryostorage