Send to

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2002 Mar 19;99(6):3842-7.

The lipofuscin component A2E selectively inhibits phagolysosomal degradation of photoreceptor phospholipid by the retinal pigment epithelium.

Author information

Margaret M. Dyson Vision Research Institute, Department of Ophthalmology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.


Daily phagocytosis of spent photoreceptor outer segments is a critical maintenance function performed by the retinal pigment epithelium (RPE) to preserve vision. Aging RPE accumulates lipofuscin, which includes N-retinylidene-N-retinylethanolamine (A2E) as the major autofluorescent component. We studied the effect of physiological levels of A2E in RPE cultures on their ability to phagocytose outer segments. A2E localized to lysosomes in cultured RPE as well as in human RPE in situ. A2E-loaded RPE cells in culture bound and internalized identical numbers of outer segments as control RPE indicating that A2E does not alter early steps of phagocytosis. A2E-loaded RPE degraded outer segment proteins efficiently but, strikingly, failed to completely digest phospholipids within 24 h. Because of the circadian rhythm of RPE phagocytosis in the eye, a delay in lipid degradation would likely result in a build up of undigested material in RPE that could contribute to the development of age-related macular degeneration.

[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center