Potential reversibility of lipofuscin accumulation.
It is well established that the lipofuscin content of many post-mitotic cell types increases progressively during normal senescence. This age-related accumulation of lipofuscin may occur either: (1) because lipofuscin, once formed, is never degraded or eliminated from cells; or (2) because, despite turnover of this pigment, the rate of lipofuscin formation exceeds the rate at which it is eliminated. Little research has been performed to distinguish between these possibilities. Several studies suggest that lipofuscin may be turned over. However, definitive demonstrations that such turnover does occur under normal circumstances are lacking. It is possible to specifically halt new lipofuscin formation in the retinal pigment epithelium (RPE) of animals at an age when significant amounts of lipofuscin have accumulated in these cells. By monitoring the RPE for possible decreases in lipofuscin content after new pigment formation has been halted, it should be possible to determine whether previously formed lipofuscin can be eliminated from the RPE.
Katz
Martin L
ML
Mason Eye Institute, University of Missouri School of Medicine, One Hospital Drive, Columbia, MO 65212, USA. katzm@health.missouri.edu