title: Lipidomics for clinical diagnosis: Dye-Assisted Laser Desorption/Ionization (DALDI) method for lipids detection in MALDI mass spectrometry imaging.
abstract: Lipid-based biomarkers for research and diagnosis are rapidly emerging to unpack the basis of person-to-person and population variations in disease susceptibility, drug and nutritional responses, to name but a few. Hence, with the advent of MALDI Mass Spectrometry Imaging, lipids have begun to be investigated intensively. However, lipids are highly mobile during tissue preparation, and are soluble in the solvent used for matrix preparation or in the fixing fluid such as formalin, resulting in substantial delocalization. In the present article, we investigated as another alternative, the possibility of using specific dyes that can absorb UV wavelengths, in order to desorb the lipids specifically from tissue sections, and are known to immobilize them in tissues. Indeed, after lipid insolubilization with chromate solution or chemical fixation with osmium tetroxide, heterocyclic-based dyes can be directly used without matrix. Taking into account the fact that some dyes have this matrix-free capability, we identified particular dyes dedicated to histological staining of lipids that could be used with MALDI mass spectrometry imaging. We stained tissue sections with either Sudan Black B, Nile Blue A, or Oil Red O. An important advantage of this assay relies on its compatibility with usual practices of histopathological investigation of lipids. As a new method, DALDI stands for Dye-Assisted Laser Desorption Ionization and allows for future clinical and histopathological applications using routine histological protocols. Additionally, this novel methodology was validated in human ovarian cancer biopsies to demonstrate its use as a suitable procedure, for histological diagnosis in lipidomics field.
authors.affiliation: 1 Laboratoire de Protéomique, Réponse Inflammatoire, Spectrométrie de Masse (PRISM), Université de Lille 1 , Cité Scientifique, Villeneuve D'Ascq, France.
authors.forename: Karim
authors.initials: K
authors.lastname: Arafah
authors.forename: Rémi
authors.initials: R
authors.lastname: Longuespée
authors.forename: Annie
authors.initials: A
authors.lastname: Desmons
authors.forename: Olivier
authors.initials: O
authors.lastname: Kerdraon
authors.forename: Isabelle
authors.initials: I
authors.lastname: Fournier
authors.forename: Michel
authors.initials: M
authors.lastname: Salzet
mesh_terms: D000818:Animals; D001391:Azo Compounds / Q000737:chemistry; D014408:Biomarkers, Tumor / Q000737:chemistry / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D004396:Coloring Agents / Q000737:chemistry; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D010078:Oxazines / Q000737:chemistry; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013194:Staining and Labeling; D053719:Tandem Mass Spectrometry; D016707:Tissue Fixation
chemical_list: D001391:Azo Compounds; D014408:Biomarkers, Tumor; D004396:Coloring Agents; D008055:Lipids; D010078:Oxazines; C008619:Nile Blue; C011049:oil red O