Concentration dependent cholesteryl-ester and wax-ester structural relationships and meibomian gland dysfunction
Autor: | Douglas Borchman, Zofia Hetman |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
0301 basic medicine
CB cholesteryl behenate Biophysics WE wax ester Infrared spectroscopy Dry eye Biochemistry Medicinal chemistry Meibum lcsh:Biochemistry 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Cholesteryl ester lcsh:QD415-436 Lipid bilayer lcsh:QH301-705.5 Conformational isomerism chemistry.chemical_classification Wax CE cholesteryl ester Wax ester TFLL tear film lipid layer 3. Good health 030104 developmental biology Hydrocarbon FTIR Fourier transform infrared lcsh:Biology (General) chemistry 030220 oncology & carcinogenesis visual_art visual_art.visual_art_medium ν̃sym the frequency of the infrared symmetric stretching band OO oleyl oleate sense organs Monoclinic crystal system Research Article |
Zdroj: | Biochemistry and Biophysics Reports Biochemistry and Biophysics Reports, Vol 21, Iss, Pp-(2020) |
ISSN: | 2405-5808 |
Popis: | Background With dry eye, the ratio of cholesteryl ester (CE) to wax ester (WE) decreases substantially in meibum, but the functional and structural consequences of this change are speculative. The aim of this study is to confirm this finding and to bridge this gap in knowledge by investigating the effect of varying CE/WE ratios on lipid structure and thermodynamics. Methods Infrared spectroscopy was use to quantify CE and WE in human meibum and to measure hydrocarbon chain conformation and thermodynamics in a cholesteryl behenate, stearyl stearate model system. Results The CE/WE molar ratio was 36% lower for meibum from donors with dry eye due to meibomian gland dysfunction compared with meibum from donors without dry eye. CE (5 mol %) dramatically increased the phase transition temperature of pure WE from -0.12 °C to 63 °C in the mixture. Above 5 mol % CB, the phase transition temperature increased linearly, from 68.5 °C to 85 °C. In the ordered state, CE caused an increase in lipid order from about 72% trans rotamers to about 86% trans rotamers. Above 10% CE, the hydrocarbon chains were arranged in a monoclinic geometry. Conclusions The CE/WE is lower in meibum from donors with dry eye due to meibomian-gland dysfunction. Major conformational changes in the hydrocarbon chains of wax and cholesteryl ester mixtures begin to occur with just 5% CB and above. General significance CE-WE interactions may be important for in understanding lipid layer structure and functional relationships on the surface of tears, skin and plants. Highlights • The CE/WE is lower in meibum from donors with meibomian-gland dysfunction. • CE may be important for the tear film lipid layer structure and function. • CE-WE interactions may be important on the surface of tears, skin and plants. • Conformational changes in WE and CE mixtures begin to occur with just 5% CE. • CE, cholesteryl ester; WE, wax ester. |
Databáze: | OpenAIRE |
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