The Bisretinoids of RPE Lipofuscin: A Complex Mixture
Vitamin A aldehyde-derived compounds accumulate in retinal pigment epithelial (RPE) cells as bisretinoid lipofuscin pigments and have been linked to some retinal disorders, including recessive ABCA4-related disease, dominant ELOVL-4-related maculopathy, retinal degeneration caused by mutations in the Best-1 gene, and age-related macular degeneration. These bisretinoid compounds are likely unique to RPE cells. A2E is the best known but is not the only bisretinoid constituent of RPE lipofuscin; the others include all-trans-retinal dimer, all-trans-retinal dimer-PE, all-trans-retinal dimer-E, and A2-dihydropyridine-phosphatidylethanolamine (A2-DHP-PE). Isomers and photooxidized forms of these compounds are further additions to this mixture and all are constituents of human RPE lipofuscin.
KeywordsBisretinoids Retinal pigment epithelium Lipofuscin Photooxidation Vitamin A aldehyde Macular degeneration ABCA4 ELOVL-4
This work was supported by National Institutes of Health Grant EY12951 (to JRS) and a grant from Research to Prevent Blindness to the Department of Ophthalmology. JRS is the recipient of a Research to Prevent Blindness Senior Investigator Award.
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