Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films
Open Access
- 1 January 2009
- journal article
- cornea
- Published by Association for Research in Vision and Ophthalmology (ARVO) in Investigative Ophthalmology & Visual Science
- Vol. 50 (1), 140-151
- https://doi.org/10.1167/iovs.08-2097
Abstract
Purpose. Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. methods. Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (Π-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. results. The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37°C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in Π-T profiles and the microscopic appearance of the films. conclusions. It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film.This publication has 27 references indexed in Scilit:
- Adsorption of apo- and holo-tear lipocalin to a bovine Meibomian lipid filmExperimental Eye Research, 2008
- The Surface Activity of Purified Ocular Mucin at the Air-Liquid Interface and Interactions With Meibomian LipidsCornea, 2006
- Surface Pressure Measurements of Human Tears and Individual Tear Film Components Indicate That Proteins Are Major Contributors to the Surface PressureCornea, 2005
- Meibomian Gland Dysfunction: A Clinical Scheme for Description, Diagnosis, Classification, and GradingThe Ocular Surface, 2003
- Modern physicochemical research on Langmuir monolayersAdvances in Colloid and Interface Science, 2001
- Tear lipocalins: potential lipid scavengers for the corneal surface.1999
- Binding studies of tear lipocalin: the role of the conserved tryptophan in maintaining structure, stability and ligand affinityBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1999
- Structural changes in human tear lipocalins associated with lipid bindingBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1998
- Model for Ocular Tear Film FunctionCornea, 1996
- Tear lipocalins bind a broad array of lipid ligandsCurrent Eye Research, 1995