. RPE lipofuscin in ageing and age-related maculardegeneration

摘要

Lipofuscin accumulates throughout life in the RPE as a result of oxidative damage to photoreceptor membranes. At old age, lipofuscin trapped in lyso-somes is a major cellular constituent and can occupy as much as 25% of the free cytoplasmic space1. It has been postulated that excessive lysosomal accumulation of lipofuscin in RPE cells impedes metabolic activity of these cells and that lipofuscin contributes to the pathogenesis of age-related macular degeneration (AMD)1"6. These concepts are supported by the finding that elevated levels of lipofuscin in donor eyes are associated with decreased numbers of photoreceptors7, and by the striking parallels in the age-relation and topography of lipofuscin in donor eyes and AMD5. Loss of visual function in inherited diseases such as Stargardt's disease8 and Batten's disease9 has also been associated with excessive accumulation of lipofuscin-like materials in the RPE.