title: Anatomical distribution of lipids in human brain cortex by imaging mass spectrometry.
abstract: Molecular mass images of tissues will be biased if differences in the physicochemical properties of the microenvironment affect the intensity of the spectra. To address this issue, we have performed-by means of MALDI-TOF mass spectrometry-imaging on slices and lipidomic analysis in extracts of frontal cortex, both from the same postmortem tissue samples of human brain. An external calibration was used to achieve a mass accuracy of 10 ppm (1σ) in the spectra of the extracts, although the final assignment was based on a comparison with previously reported species. The spectra recorded directly from tissue slices (imaging) show excellent s/n ratios, almost comparable to those obtained from the extracts. In addition, they retain the information about the anatomical distribution of the molecular species present in autopsied frozen tissue. Further comparison between the spectra from lipid extracts devoid of proteins and those recorded directly from the tissue unambiguously show that the differences in lipid composition between gray and white matter observed in the mass images are not an artifact due to microenvironmental influences of each anatomical area on the signal intensity, but real variations in the lipid composition.
authors.affiliation: Department of Chemical Physics, Faculty of Science and Technology, University of the Basque Country, Bº Sarriena s/n, 48940 Leioa, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Veloso
authors.forename: Egoitz
authors.initials: E
authors.lastname: Astigarraga
authors.forename: Gabriel
authors.initials: G
authors.lastname: Barreda-Gómez
authors.forename: Iván
authors.initials: I
authors.lastname: Manuel
authors.forename: Isidro
authors.initials: I
authors.lastname: Ferrer
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Giralt
authors.forename: Begoña
authors.initials: B
authors.lastname: Ochoa
authors.forename: Olatz
authors.initials: O
authors.lastname: Fresnedo
authors.forename: Rafael
authors.initials: R
authors.lastname: Rodríguez-Puertas
authors.forename: José A
authors.initials: JA
authors.lastname: Fernández
mesh_terms: D005625:Frontal Lobe / Q000737:chemistry* / Q000378:metabolism; D005994:Glycerophosphates / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D057054:Molecular Imaging / Q000379:methods*; D009928:Organ Specificity; D025341:Principal Component Analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D005994:Glycerophosphates