Loss of Pigment Epithelial Cells Is Prevented by Autophagy

The retinal pigment epithelial cells (RPECs) undertake essential functions for normal outer retinal physiology. RPECs are associated with various retinal pathologic conditions. Owing to its anatomical location in one of the most redox-active interfaces in the human body and the responsibility for routine phagocytosis of photoreceptor outer segments, RPECs are continuously subjected to endogenous and exogenous oxidative injury. Oxidative injury to RPECs causes loss of RPECs, leading to retinal degeneration. It is noticeable that age-related retinal degeneration usually occurs surprisingly late in life irrespective of the constant exposure of RPECs to oxidative stress. This is probably because of that RPECs are more resistant to oxidative stress. Autophagy is involved in cellular homeostasis of retinal pigment epithelium and may be important to ensure the functional integrity of the retina. Furthermore, autophagy seems to regulate functional pathways associated with ocular pathological conditions, including aged macular degeneration which is associated with the loss of RPECs.