title: Tear film lipids.
abstract: Human meibomian gland secretions (MGS, or meibum) are formed from a complex mixture of lipids of different classes such as wax esters, cholesteryl esters, (O-acyl)-ω-hydroxy fatty acids (OAHFA) and their esters, acylglycerols, diacylated diols, free fatty acids, cholesterol, and a smaller amount of other polar and nonpolar lipids, whose chemical nature and the very presence in MGS have been a matter of intense debates. The purpose of this review is to discuss recent results that were obtained using different experimental techniques, estimate limitations of their usability, and discuss their biochemical, biophysical, and physiological implications. To create a lipid map of MGS and tears, the results obtained in the author's laboratory were integrated with available information on chemical composition of MGS and tears. The most informative approaches that are available today to researchers, such as HPLC-MS, GC-MS, and proton NMR, are discussed in details. A map of the meibomian lipidome (as it is seen in reverse phase liquid chromatography/mass spectrometry experiments) is presented. Directions of future efforts in the area are outlined.
authors.affiliation: Department of Ophthalmology and the Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA. Electronic address: igor.butovich@utsouthwestern.edu.
authors.forename: Igor A
authors.initials: IA
authors.lastname: Butovich
mesh_terms: D002788:Cholesterol Esters / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D056148:Chromatography, Reverse-Phase; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids / Q000502:physiology*; D013058:Mass Spectrometry / Q000379:methods; D008537:Meibomian Glands / Q000378:metabolism*; D013666:Tears / Q000378:metabolism*; D014885:Waxes / Q000032:analysis / Q000737:chemistry
chemical_list: D002788:Cholesterol Esters; D004952:Esters; D005227:Fatty Acids; D008055:Lipids; D014885:Waxes
keywords: chromatography; lipidomics; lipids; mass spectrometry; meibomian gland secretions; meibum