Cholesteryl esters as a depot for very long chain fatty acids in human meibum.
Human meibomian gland secretions (also known as meibum) were analyzed for the presence of cholesteryl esters (Chl-E) using HPLC in combination with atmospheric pressure chemical ionization mass spectrometry. A special procedure based on detection of the in-source generated ion m/z 369 was developed to monitor all Chl-E simultaneously. The structures of the detected compounds were studied using in-source and postsource fragmentation of the precursor (M+H)(+) ions. In concordance with previous studies, Chl-E were found in all of the tested samples and comprised approximately 31% of the entire lipid pool (w/w, dry weight). There were at least 20 different saturated and unsaturated Chl-E species observed, whose fatty acid residues ranged from C18 to C34. Monounsaturated fatty acids were the most visible components of the Chl-E pool. The eleven most prominent compounds were: C20:0-, C22:1-, C22:0-, C24:1-, C24:0, C25:0-, C26:1-, C26:0-, C28:1-, C28:0-, and C30:1-Chl-E. Other Chl-containing compounds were detected but not identified at the time. Therefore, Chl-E are a depot for very long chain saturated and monounsaturated fatty acids in human meibum.
Department of Ophthalmology and Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390. Electronic address: igor.butovich@utsouthwestern.edu.
Igor A
IA
Butovich
D002788:Cholesterol Esters / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D008537:Meibomian Glands / Q000378:metabolism*; D015394:Molecular Structure
D002788:Cholesterol Esters; D005227:Fatty Acids