Meibomian Gland secretion lipid analysis

Meibomian glands (MG) are excretory glands that secrete an oily substance, meibum, that spreads across the ocular surface and combine with secretions produced by other ocular structures such as the Lacrimal gland in order to create a thin film that serves to protect the ocular surface. The chemical composition of the lipid layer has long been identified as a key element in the protective efficacy of the tear film.1,2 This area of research has been an interest of this lab over the past several years.

Comprehensive lipidomic analysis have been performed to elucidate the biological basis of the normal physiology of the tear film as well as the pathophysiology of abnormalities that involve meibomian gland dysfunction.  Due to the small sampling size of meibomian lipids,3,4,5  researchers in our lab have devised analytical methods with both high sensitivity and selectivity for testing samples.  During past years,  individual and a combination of different analytical techniques have been employed at our lab for lipid analysis such as TLC,6-8  TLC/GLC,4,9,10 GC-MS,6-8 TLC-GC-MS,12,13 GLC14 and   HPLC 6-8,11

In collaboration with Dr. Igor Butovich’s lab5,15 (http://www4.utsouthwestern.edu/butovichlab), Dr. McCulley and his laboratory colleagues have been conducting a more detailed and comprehensive analysis of meibomian lipids in the relation to possible therapeutic effects of new drug candidates and food supplements. The combination of HPLC and mass spectrometry MS used in those experiments supplies both structural and quantitative information about the compounds.  During the past decade, as analytical techniques have become more perfected,  recent studies5,15 are providing even more comprehensive information on the biochemistry of meibum than before. These latest findings are used to advance our views on the tear film structure and composition.

 

References:

  1. McCulley JP, Shine W. A compositional based model for the tear film lipid layer. Trans Am Ophthalmol Soc. 1997;95:79-88.
  2. McCulley JP, Shine WE. Tear film structure and dry eye. Contactologia. 1998;20:145-149
  3. Cory CC, Hinks W, Burton J L, Shuster S. Meibomian gland secretion in the red eyes of rosacea. Brit J Dermatology 1973; 89:25-27.
  4. McCulley JP, Dougherty JM, Deneau D. Classification of Chronic Blepharitis. Ophthalmology 1982;89: 1173-1180.
  5. Butovich I, Uchiyama E, Di Pascuale MA, McCulley JP. Liquid Chromatography-mass spectrometric analysis of lipids present in human meibomian gland secretions. Lipids.2007;42(8):765-776
  6. Shine W(a), McCulley JP. Polar lipids in human meibomian gland secretions. Curr eye Res. 2003;26(2):89-94
  7. Shine W, McCulley JP. Meibomianitis. Polar lipid Abnormalities.  Cornea 2004;23(8):781-783
  8. Shine W, McCulley JP. Keratoconjuntivitis Sicca Associated with meibomian Secretion Polar Lipid abnormality. Arch Ophthalmol 1998;116:849-852
  9. Shine, McCulley. The Role of Cholesterol in Chronic Blepharitis. Invest Ophthalmol Vis Sci. 1991;32: 2272-2280
  10. Dougherty JM(a), McCulley JP. Bacterial lipases and chronic blepharitis. Invest Ophthalmol Vis Sci. 1986;27(4):486-491.
  11. Shine WE(b), McCulley JP, Pandya AG. Minocycline effect on meibomian gland lipids in meibomianitis patients. Exp Eye Res 2003;76:417-420
  12. Shine WE, McCulley JP. Association of meibum oleic acid with meibomian seborrhea. Cornea 2000;19(1):72-74.
  13. Shine W, McCulley JP. Meibomian Gland Triglyceride Fatty Acid Differences in Chronic Blepharitis Patients. Cornea. 1996;15(4): 340-346.
  14. Osgood JK, Dougherty Jm,  McCulley JP. The Role of Wax and Sterol Esters of Meibomian Secretions in Chronic Blepharitis. Invest Ophthalmol Vis Sci.1989;30:1958-1961.
  15. Butovich IA, Uchiyama E, McCulley JP. Lipids of human meibum: mass-spectrometric analysis and structural elucidation. J Lipid Res.2007;48(10):2220-35.
  16. Eduardo Uchiyama, MD, Mario Di Pascuale, MD, Igor Butovich, MD, James McCulley, MD; "Impact on Ocular Surface Evaporation of an Artificial Tear Solution Containing Hydroxypropyl (HP)Guar," Eye & Contact Lens, November 2008, Vol. 34, No. 6, pgs. 331-334.
  17. Butovich IA. Cholesteryl esters as a depot for very long chain fatty acids in human meibum.
    J Lipid Res. (2009) 50(3): (in print)

  18. Millar TJ, Mudgil P, Butovich IA, Palaniappan CK. Adsorption of human tear lipocalin to human Meibomian lipid films. Invest Ophthalmol Vis Sci. (2009) 50(1):140-151

  19. Butovich I.A., Millar T.J., Ham B.M. Understanding and analyzing meibomian lipids – a review.
    Curr Eye Res. (2008) 33(5):405-420

  20. Butovich I.A. On the lipid composition of human meibum and tears: Comparative analysis of nonpolar lipids. Invest Ophthalmol Vis Sci. (2008) 49(9):3779-3789

  21.  Butovich I.A., Lukyanova SM.
    Inhibition of lipoxygenases and cyclooxygenases by linoleyl hydroxamic acid: comparative in vitro studies. J Lipid Res. (2008) 49(6):1284-1294