Antioxidant Properties of Melanin in Retinal Pigment Epithelial Cells
- 1 March 2006
- journal article
- Published by Wiley in Photochemistry and Photobiology
- Vol. 82 (2), 474-479
- https://doi.org/10.1562/2005-10-21-ra-725
Abstract
The retinal pigment epithelium (RPE) is a monolayer of highly pigmented cells lining the inner aspect of Bruch's membrane. This pigmentation is due to eumelanin and a possible antioxidant role of melanin is reported here. The photo-oxidation of A2E, a constituent of RPE lipofuscin, leads to the sequential addition of up to nine oxygen atoms and/or the addition or loss of two hydrogen atoms. These photo-oxidations were investigated in the presence and absence of either calf or human RPE melanin in A2E-laden RPE cells. It was found that calf melanin was protective against the photo-oxidation of A2E, with an inhibition of oxidation of up to 50% in the case of the addition of two oxygen atoms. Calf melanin was also protective against blue light-induced damage to RPE cells. In addition this ability appears to decrease in humans as they grow older. With aging, a melanin-lipofuscin complex called melanolipofuscin forms. It is suggested that the oxidation or photo-oxidation of A2E in vivo may contribute to the age-related deterioration of the anti-oxidant role of RPE melanin and lead to various retinal disorders, such as age-related macular degeneration.Keywords
This publication has 33 references indexed in Scilit:
- Environmental Effects on the Photochemistry of A2-E, a Component of Human Retinal Lipofuscin¶Photochemistry and Photobiology, 2007
- Observation of A2E oxidation products in human retinal lipofuscinExperimental Eye Research, 2004
- A2E-epoxides Damage DNA in Retinal Pigment Epithelial CellsJournal of Biological Chemistry, 2003
- Racial differences in the prevalence of age-related macular degenerationOphthalmology, 1999
- Free radical scavenging properties of melanin: Interaction of eu- and pheo-melanin models with reducing and oxidising radicalsFree Radical Biology & Medicine, 1999
- Lipofuscin accumulation in cultured retinal pigment epithelial cells reduces their phagocytic capacityCurrent Eye Research, 1998
- Interaction of melanin with carbon- and oxygen-centered radicals from methanol and ethanolFree Radical Biology & Medicine, 1995
- Blue Light-induced Reactivity of Retinal Age PigmentJournal of Biological Chemistry, 1995
- PHOTOSENSITIZATION OF MELANINS: A COMPARATIVE STUDYPhotochemistry and Photobiology, 1985
- Amorphous Semiconductor Switching in MelaninsScience, 1974