Biophysical and morphological evaluation of human normal and dry eye meibum using hot stage polarized light microscopy

Igor A. Butovich, Hua Lu, Anne McMahon, Howard Ketelson, Michelle Senchyna, David Meadows, Elaine Campbell, Mike Molai, Emily Linsenbardt

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Purpose. To study melting characteristics and the morphology of human and mouse meibum. Methods. Hot stage cross-polarized light microscopy (HSPM) and immunohistochemical approaches were used. Results. Isolated human meibum, and meibum of mice (either isolated or within the meibomian ducts of mice), were found to be in liquid-crystal state at physiological temperatures. Melting of both types of meibum started at approximately 10°C and was completed at approximately 40°C. Melting curves of isolated meibum and meibum inside the meibomian ducts were multiphasic with at least two or three clearly defined phase transition temperatures, typically at approximately 12 ± 2°C (minor transition), 21 ± 3°C, and 32 ± 3°C, regardless the source of meibum. Melting was highly cooperative in nature. Samples of abnormal human meibum collected from dry eye patients with meibomian gland dysfunction often showed an increased presence of nonlipid, nonmelting, nonbirefringent, chloroform-insoluble inclusions of a protein nature. The inclusions were positively stained for cytokeratins. The presence of these inclusions was semiquantitatively characterized using a newly proposed 0 to 4 scale. In the presence of large amounts of these inclusions, melting characteristics of meibum and its structural integrity were altered. Conclusions. HSPM is an effective tool that is suitable for biophysical and morphological evaluation of meibum. Morphological properties and melting characteristics of human meibum were found to be similar to those of mice. Abnormal meibum of many dry eye patients contained large quantities of nonlipid, protein-like inclusions, which were routinely absent in meibum of normal controls.

Original languageEnglish (US)
Pages (from-to)87-101
Number of pages15
JournalInvestigative Ophthalmology and Visual Science
Volume55
Issue number1
DOIs
StatePublished - Nov 26 2013

Keywords

  • Biophysics
  • Hot stage polarized light microscopy
  • Lipids
  • Meibomian glands
  • Phase transitions
  • Rheology

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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