Purpose. The aim of this study was to assess if lipofuscin granules, isolated from the human retinal pigment epithelium (RPE), have the potential to exert any adverse effect on cell function. Methods. Freshly isolated lipofuscin granules were either 1) incubated with a) lipid membranes, b) antioxidant enzymes or c) lysosomal enzymes in the presence and absence of white light (60-80mW/cm2) or 2) fed to cultured human RPE cells, incubated under standard cell culture conditions. Lipid peroxidation and enzyme activities were monitored over different time periods. Results. Lipofuscin induced a 2% increase in the rate of oxidation of lipid membranes in the dark. However, in the presence of white light, the effect was enhanced by 30%. This photo-oxidative potential was mainly associated with methanol/water soluble components of lipofuscin. Incubation of these granules with antioxidant or lysosomal enzymes, in the presence of white light, produced a 50% or 30% decrease in activity respectively. No effect was observed in the dark. Similar trends were observed when lipofuscin granules were fed to RPE cells. Conclusion. This study demonstrates that lipofuscin has the potential to be phototoxic to the RPE and may play a major role in retinal light damage and diseases such as age-related macular degeneration.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience