title: Lipid composition of the human eye: are red blood cells a good mirror of retinal and optic nerve fatty acids?
abstract: BACKGROUND
  The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics.
  
  
  RESULTS
  Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS). Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA), retinal very-long chain polyunsaturated fatty acids (VLC-PUFA) or optic nerve plasmalogens.
  
  
  CONCLUSIONS
  LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on optic nerve neuropathies or retinal diseases displaying photoreceptors degeneration.
authors.affiliation: CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, Dijon, France. acar@dijon.inra.fr
authors.forename: Niyazi
authors.initials: N
authors.lastname: Acar
authors.forename: Olivier
authors.initials: O
authors.lastname: Berdeaux
authors.forename: Stéphane
authors.initials: S
authors.lastname: Grégoire
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Cabaret
authors.forename: Lucy
authors.initials: L
authors.lastname: Martine
authors.forename: Philippe
authors.initials: P
authors.lastname: Gain
authors.forename: Gilles
authors.initials: G
authors.lastname: Thuret
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Creuzot-Garcher
authors.forename: Alain M
authors.initials: AM
authors.lastname: Bron
authors.forename: Lionel
authors.initials: L
authors.lastname: Bretillon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004912:Erythrocytes / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000097:blood*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male; D009900:Optic Nerve / Q000737:chemistry*; D012160:Retina / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D005227:Fatty Acids