title: A comparison of patient matched meibum and tear lipidomes.
abstract: OBJECTIVE
  To quantify the molecular lipid composition of patient-matched tear and meibum samples and compare tear and meibum lipid molecular profiles.
  
  
  METHODS
  Lipids were extracted from tears and meibum by bi-phasic methods using 10:3 tert-butyl methyl ether:methanol, washed with aqueous ammonium acetate, and analyzed by chip-based nanoelectrospray ionization tandem mass spectrometry. Targeted precursor ion and neutral loss scans identified individual molecular lipids and quantification was obtained by comparison to internal standards in each lipid class.
  
  
  RESULTS
  Two hundred and thirty-six lipid species were identified and quantified from nine lipid classes comprised of cholesterol esters, wax esters, (O-acyl)-ω-hydroxy fatty acids, triacylglycerols, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylserine. With the exception of phospholipids, lipid molecular profiles were strikingly similar between tears and meibum.
  
  
  CONCLUSIONS
  Comparisons between tears and meibum indicate that meibum is likely to supply the majority of lipids in the tear film lipid layer. However, the observed higher mole ratio of phospholipid in tears shows that analysis of meibum alone does not provide a complete understanding of the tear film lipid composition.
authors.affiliation: Illawara Health and Medical Research Institute and School of Health Sciences, University of Wollongong, Wollongong, New South Wales, Australia.
authors.forename: Simon H J
authors.initials: SH
authors.lastname: Brown
authors.forename: Carolina M E
authors.initials: CM
authors.lastname: Kunnen
authors.forename: Eva
authors.initials: E
authors.lastname: Duchoslav
authors.forename: Naveen K
authors.initials: NK
authors.lastname: Dolla
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kelso
authors.forename: Eric B
authors.initials: EB
authors.lastname: Papas
authors.forename: Percy
authors.initials: P
authors.lastname: Lazon de la Jara
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Willcox
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Blanksby
authors.forename: Todd W
authors.initials: TW
authors.lastname: Mitchell
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008297:Male; D008537:Meibomian Glands / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods; D013666:Tears / Q000737:chemistry*; D055815:Young Adult
chemical_list: D008055:Lipids
keywords: OAHFA; lipidome; lipidomics; lipids; mass spectrometry; meibum; tears