Zone I of Tear Microdesiccates Is a Lipid-Containing Structure.

PURPOSE Morphological features of tear microdesiccates on glass surfaces have been associated with tear fluid status. Tear-film lipids play a critical role in the pathophysiology of some ocular surface disorders. Tear microdesiccates display 4 distinctive morphological domains (zones I, II, III, and transition band). In this study, we investigated the lipid location in tear microdesiccates. METHODS Tear from individual healthy eyes (assessed by symptoms, signs, and slit-lamp examination) was collected using absorbing minisponges. One-µL aliquots were allowed to dry under ambient conditions on microscope slides. Tear microdesiccates were examined by various transmitted light microscopy methods. Tear lipids were located both by partition experiments using 2 lipophilic dyes (Oil red O and Nile blue A) mixed with tear fluid under conditions preserving morphological features of microdesiccates and by assessing the effect of 2 solvents markedly differing in polarity (water and ethanol) on the morphology of particular domains of preformed microdesiccates. RESULTS During desiccation, both Nile blue A and Oil red O became preferentially located in the outermost domain of tear microdesiccates (zone I) without affecting the formation of major fern-like crystalloids (zones II and III). Low volumes of water drastically affected fern-like crystalloids, whereas the gross morphology of zone I was maintained. Contrarily, ethanol, a less polar solvent, was a fixative for fern-like crystalloids, although it markedly affected the bulk of zone I by extracting liquid droplets out of microdesiccates and visibilizing some filamentous subcomponents. CONCLUSIONS Zone I is a hydrophobic domain, whereas zones II and III are highly hydrophilic domains of tear microdesiccates. Zone I represents a lipid-rich structure.

[1]  C. Cartes,et al.  Progress in tear microdesiccate analysis by combining various transmitted-light microscope techniques , 2016, Biological Research.

[2]  R. López-Solís,et al.  Stratification of Tear Components During Tear Microdesiccation on Vertical Glass Surfaces: A Novel Approach in Tear Fluid Assessment , 2015, Cornea.

[3]  F. Ortolani,et al.  Carotenoids Co-Localize with Hydroxyapatite, Cholesterol, and Other Lipids in Calcified Stenotic Aortic Valves. Ex Vivo Raman Maps Compared to Histological Patterns , 2015, European journal of histochemistry : EJH.

[4]  Ali M. Masmali,et al.  Application of a new grading scale for tear ferning in non-dry eye and dry eye subjects. , 2015, Contact lens & anterior eye : the journal of the British Contact Lens Association.

[5]  V. Andrés,et al.  Oil Red O and Hematoxylin and Eosin Staining for Quantification of Atherosclerosis Burden in Mouse Aorta and Aortic Root. , 2015, Methods in molecular biology.

[6]  K. Tsubota,et al.  Alteration of tear mucin 5AC in office workers using visual display terminals: The Osaka Study. , 2014, JAMA ophthalmology.

[7]  R. López-Solís,et al.  Dynamics of tear fluid desiccation on a glass surface: a contribution to tear quality assessment , 2014, Biological Research.

[8]  L. Tong,et al.  Lipidomic analysis of human tear fluid reveals structure-specific lipid alterations in dry eye syndrome1[S] , 2014, Journal of Lipid Research.

[9]  Markus R. Wenk,et al.  Extensive characterization of human tear fluid collected using different techniques unravels the presence of novel lipid amphiphiles1[S] , 2014, Journal of Lipid Research.

[10]  I. Butovich Tear film lipids. , 2013, Experimental eye research.

[11]  S. Pflugfelder,et al.  T helper cytokines in dry eye disease. , 2013, Experimental eye research.

[12]  M. Srur,et al.  Microdesiccates produced from normal human tears display four distinctive morphological components. , 2013, Biological research.

[13]  T. Millar,et al.  The international workshop on meibomian gland dysfunction: report of the subcommittee on anatomy, physiology, and pathophysiology of the meibomian gland. , 2011, Investigative ophthalmology & visual science.

[14]  Jun Shimazaki,et al.  The international workshop on meibomian gland dysfunction: report of the definition and classification subcommittee. , 2011, Investigative ophthalmology & visual science.

[15]  B. Glasgow,et al.  The international workshop on meibomian gland dysfunction: report of the subcommittee on tear film lipids and lipid-protein interactions in health and disease. , 2011, Investigative ophthalmology & visual science.

[16]  A. Tomlinson,et al.  Comparison of Human Tear Film Osmolarity Measured by Electrical Impedance and Freezing Point Depression Techniques , 2010, Cornea.

[17]  I. Gipson,et al.  Membrane-tethered mucins have multiple functions on the ocular surface. , 2010, Experimental eye research.

[18]  F. Mantelli,et al.  Mucin-type O-glycans in tears of normal subjects and patients with non-Sjögren's dry eye. , 2009, Investigative ophthalmology & visual science.

[19]  R. López-Solís,et al.  A Protein Dye-Binding Assay on Cellulose Membranes for Tear Protein Quantification: Use of Conventional Schirmer Strips , 2007, Cornea.

[20]  R. López-Solís,et al.  Use of Polyurethane Minisponges to Collect Human Tear Fluid , 2006, Cornea.

[21]  Kai Bruns,et al.  SELDI-TOF-MS ProteinChip array profiling of tears from patients with dry eye. , 2005, Investigative ophthalmology & visual science.

[22]  A. Tomlinson,et al.  Spatial location studies on the chemical composition of human tear ferns , 2000, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[23]  C. Reichardt Solvents and Solvent Effects in Organic Chemistry , 1988 .