title: Analysis of the composition of lipid in human meibum from normal infants, children, adolescents, adults, and adults with meibomian gland dysfunction using ¹H-NMR spectroscopy.
abstract: OBJECTIVE
  This study represents a first step toward the evaluation of possible compositional differences in meibum from normal donors (Mn) and donors with meibomian gland dysfunction (Md) by (1)H-NMR spectroscopy. The results highlight the applicability of (1)H-NMR spectroscopy for the quantitative analysis of waxes, cholesteryl esters, and glycerides in meibum lipid (ML).
  
  
  METHODS
  Meibum was obtained from 41 normal donors and 51 donors with meibomian gland dysfunction (MGD). (1)H-NMR spectroscopy was used to quantify the amount of waxes, glycerides, and cholesteryl esters in human meibum.
  
  
  RESULTS
  The relative amount of cholesteryl esters in Mn increased with age and was 40% (P < 0.05) lower in Md. Interestingly, the relative levels of cholesteryl esters in infant meibum were comparable to those in Md. The relative amounts of glycerides were not affected significantly by age or MGD.
  
  
  CONCLUSIONS
  The changes in cholesteryl ester could be used as a molecular marker for MGD and could potentially be applied to follow the efficacy of drug therapy in the treatment of MGD. The similarity of the levels of cholesteryl esters in infant meibum and Md suggests that the relative amounts of these meibum components alone are unlikely to be responsible for the increased stability of the infant tear film and decreased stability of the tear film with MGD. This study reveals the complexity of human MLs and the changes that occur with age and disease. Understanding the factors that lead to such variations is of utmost relevance in the design of effective therapies.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, USA.
authors.forename: Rashmi K
authors.initials: RK
authors.lastname: Shrestha
authors.forename: Douglas
authors.initials: D
authors.lastname: Borchman
authors.forename: Gary N
authors.initials: GN
authors.lastname: Foulks
authors.forename: Marta C
authors.initials: MC
authors.lastname: Yappert
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Milliner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D002788:Cholesterol Esters / Q000378:metabolism*; D005141:Eyelid Diseases / Q000378:metabolism*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008537:Meibomian Glands / Q000378:metabolism*; D008875:Middle Aged; D019906:Nuclear Magnetic Resonance, Biomolecular; D012629:Sebum / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism*; D014885:Waxes / Q000378:metabolism*; D055815:Young Adult
chemical_list: D002788:Cholesterol Esters; D014280:Triglycerides; D014885:Waxes