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Identification and quantitation of carotenoids and their metabolites in the tissues of the human eye.
Exp Eye Res. 2001 Mar; 72(3):215-23.EE

Abstract

There is increasing evidence that the macular pigment carotenoids, lutein and zeaxanthin, may play an important role in the prevention of age-related macular degeneration, cataract, and other blinding disorders. Although it is well known that the retina and lens are enriched in these carotenoids, relatively little is known about carotenoid levels in the uveal tract and in other ocular tissues. Also, the oxidative metabolism and physiological functions of the ocular carotenoids are not fully understood. Thus, we have set out to identify and quantify the complete spectrum of dietary carotenoids and their oxidative metabolites in a systematic manner in all tissues of the human eye in order to gain better insight into their ocular physiology. Human donor eyes were dissected, and carotenoid extracts from ocular tissues [retinal pigment epithelium/choroid (RPE/choroid), macula, peripheral retina, ciliary body, iris, lens, vitreous, cornea, and sclera] were analysed by high-performance liquid chromatography (HPLC). Carotenoids were identified and quantified by comparing their chromatographic and spectral profiles with those of authentic standards. Nearly all ocular structures examined with the exception of vitreous, cornea, and sclera had quantifiable levels of dietary (3R,3'R,6'R)-lutein, zeaxanthin, their geometrical (E / Z) isomers, as well as their metabolites, (3R,3'S,6'R)-lutein (3'-epilutein) and 3-hydroxy-beta,epsilon-caroten-3'-one. In addition, human ciliary body revealed the presence of monohydroxycarotenoids and hydrocarbon carotenoids, while only the latter group was detected in human RPE/choroid. Uveal structures (iris, ciliary body, and RPE/choroid) account for approximately 50% of the eye's total carotenoids and approximately 30% of the lutein and zeaxanthin. In the iris, these pigments are likely to play a role in filtering out phototoxic short-wavelength visible light, while they are more likely to act as antioxidants in the ciliary body. Both mechanisms, light screening and antioxidant, may be operative in the RPE/choroid in addition to a possible function of this tissue in the transport of dihydroxycarotenoids from the circulating blood to the retina. This report lends further support for the critical role of lutein, zeaxanthin, and other ocular carotenoids in protecting the eye from light-induced oxidative damage and aging.

Authors+Show Affiliations

Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT 84132, USA. paul.bernstein@hsc.utah.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

11180970

Citation

Bernstein, P S., et al. "Identification and Quantitation of Carotenoids and Their Metabolites in the Tissues of the Human Eye." Experimental Eye Research, vol. 72, no. 3, 2001, pp. 215-23.
Bernstein PS, Khachik F, Carvalho LS, et al. Identification and quantitation of carotenoids and their metabolites in the tissues of the human eye. Exp Eye Res. 2001;72(3):215-23.
Bernstein, P. S., Khachik, F., Carvalho, L. S., Muir, G. J., Zhao, D. Y., & Katz, N. B. (2001). Identification and quantitation of carotenoids and their metabolites in the tissues of the human eye. Experimental Eye Research, 72(3), 215-23.
Bernstein PS, et al. Identification and Quantitation of Carotenoids and Their Metabolites in the Tissues of the Human Eye. Exp Eye Res. 2001;72(3):215-23. PubMed PMID: 11180970.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification and quantitation of carotenoids and their metabolites in the tissues of the human eye. AU - Bernstein,P S, AU - Khachik,F, AU - Carvalho,L S, AU - Muir,G J, AU - Zhao,D Y, AU - Katz,N B, PY - 2001/2/22/pubmed PY - 2001/5/22/medline PY - 2001/2/22/entrez SP - 215 EP - 23 JF - Experimental eye research JO - Exp. Eye Res. VL - 72 IS - 3 N2 - There is increasing evidence that the macular pigment carotenoids, lutein and zeaxanthin, may play an important role in the prevention of age-related macular degeneration, cataract, and other blinding disorders. Although it is well known that the retina and lens are enriched in these carotenoids, relatively little is known about carotenoid levels in the uveal tract and in other ocular tissues. Also, the oxidative metabolism and physiological functions of the ocular carotenoids are not fully understood. Thus, we have set out to identify and quantify the complete spectrum of dietary carotenoids and their oxidative metabolites in a systematic manner in all tissues of the human eye in order to gain better insight into their ocular physiology. Human donor eyes were dissected, and carotenoid extracts from ocular tissues [retinal pigment epithelium/choroid (RPE/choroid), macula, peripheral retina, ciliary body, iris, lens, vitreous, cornea, and sclera] were analysed by high-performance liquid chromatography (HPLC). Carotenoids were identified and quantified by comparing their chromatographic and spectral profiles with those of authentic standards. Nearly all ocular structures examined with the exception of vitreous, cornea, and sclera had quantifiable levels of dietary (3R,3'R,6'R)-lutein, zeaxanthin, their geometrical (E / Z) isomers, as well as their metabolites, (3R,3'S,6'R)-lutein (3'-epilutein) and 3-hydroxy-beta,epsilon-caroten-3'-one. In addition, human ciliary body revealed the presence of monohydroxycarotenoids and hydrocarbon carotenoids, while only the latter group was detected in human RPE/choroid. Uveal structures (iris, ciliary body, and RPE/choroid) account for approximately 50% of the eye's total carotenoids and approximately 30% of the lutein and zeaxanthin. In the iris, these pigments are likely to play a role in filtering out phototoxic short-wavelength visible light, while they are more likely to act as antioxidants in the ciliary body. Both mechanisms, light screening and antioxidant, may be operative in the RPE/choroid in addition to a possible function of this tissue in the transport of dihydroxycarotenoids from the circulating blood to the retina. This report lends further support for the critical role of lutein, zeaxanthin, and other ocular carotenoids in protecting the eye from light-induced oxidative damage and aging. SN - 0014-4835 UR - https://www.unboundmedicine.com/medline/citation/11180970/Identification_and_quantitation_of_carotenoids_and_their_metabolites_in_the_tissues_of_the_human_eye_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014-4835(00)90954-0 DB - PRIME DP - Unbound Medicine ER -