title: A new simple and rapid LC-ESI-MS/MS method for quantification of plasma oxysterols as dimethylaminobutyrate esters. Its successful use for the diagnosis of Niemann-Pick type C disease.
abstract: Two oxysterols, cholestan-3β,5α,6β-triol (C-triol) and 7-ketocholesterol (7-KC), have been recently proposed as diagnostic markers of Niemann-Pick type C (NP-C) disease, representing a potential alternative diagnostic tool to the more invasive and time consuming filipin test in cultured fibroblasts. Usually, the oxysterols are detected and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using atmospheric pressure chemical ionization (APCI) or electro-spray-ionization (ESI) sources, after a variety of derivatization procedures to enhance sensitivity. We developed a sensitive LC-MS/MS method to quantify the oxysterols in plasma as dimethylaminobutyrate ester, suitable for ESI analysis. This method, with an easy liquid-phase extraction and a short derivatization procedure, has been validated to demonstrate specificity, linearity, recovery, lowest limit of quantification, accuracy and precision. The assay was linear over a concentration range of 0.5-200ng/mL for C-triol and 1.0-200ng/mL for 7-KC. Intra-day and inter-day coefficients of variation (CV%) were <15% for both metabolites. Receiver operating characteristic analysis estimates that the area under curve was 0.998 for C-triol, and 0.972 for 7-KC, implying a significant discriminatory power for the method in this patient population of both oxysterols. In summary, our method provides a simple, rapid and non-invasive diagnostic tool for the biochemical diagnosis of NP-C disease.
authors.affiliation: Laboratory of Metabolic Biochemistry, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. Electronic address: sara.boenzi@opbg.net.
authors.forename: Sara
authors.initials: S
authors.lastname: Boenzi
authors.affiliation: Division of Metabolism, Department of Pediatric Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Deodato
authors.affiliation: Division of Metabolism, Department of Pediatric Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Taurisano
authors.affiliation: Division of Metabolism, Department of Pediatric Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Martinelli
authors.affiliation: Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Verrigni
authors.affiliation: Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Rosalba
authors.initials: R
authors.lastname: Carrozzo
authors.affiliation: Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Bertini
authors.affiliation: Laboratory of Metabolic Biochemistry, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Pastore
authors.affiliation: Division of Metabolism, Department of Pediatric Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Dionisi-Vici
authors.affiliation: Department of Biochemical Genetics, Women's and Children's Hospital, North Adelaide 5006, South Australia, Australia.
authors.forename: David W
authors.initials: DW
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D000613:Aminobutyrates / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D002777:Cholestanols / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007653:Ketocholesterols / Q000097:blood*; D008297:Male; D052556:Niemann-Pick Disease, Type C / Q000097:blood* / Q000175:diagnosis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013997:Time Factors; D055815:Young Adult
chemical_list: D000613:Aminobutyrates; D015415:Biomarkers; D002777:Cholestanols; D007653:Ketocholesterols; C000474:cholestane-3,5,6-triol; C003001:7-ketocholesterol
keywords: Dimethylaminobutyrate ester derivative; Electrospray ionization analysis; Liquid chromatography–tandem-mass spectrometry; Niemann–Pick C disease; Oxysterols