The retinal pigment epithelium (RPE) is a single layer of cells at the back of the eye next to the retina. The health of RPE cells, and their ability to support the nerve cells of the retina, depend on well-functioning RPE cell metabolism as a source of energy.
Put another way, RPE cellular energy production is central to the maintenance of healthy retina cells and the gatekeepers of cell death.
Scientists are trying to understand how an imbalance between how much energy the RPE cells need and how much energy the cells actually produce contributes to macular degeneration and its progression. Through research, we are looking at ways to restore health to the aging eye by improving cellular metabolism.
BrightFocus Grantees are currently looking at the decline in cellular energy production in the RPE and the mitochondria, which are the cell’s “powerhouse” for energy production.
The Powerhouse of the Cell
Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Each cell contains hundreds to thousands of mitochondria, which float inside the cells.
Explore More of Our 360° Research Approach
- Retinal Pigment Epithelium
- Geographic Atrophy
- Immune Response
- Diet and Nutrition
- Regenerating Cells
- Innovative Treatment Approaches
Retinal Pigment Epithelium
It is generally thought that age-related macular degeneration (AMD) begins in the retinal pigment epithelium (RPE), a single layer of cells next to the retina, whose job is to transport molecules in and out to nourish the retina and dispose of waste. The RPE’s ability to do its job can be compromised by age, oxidative stress, inflammation, and other factors causing the immune system to kick in and overact.
Some patients with age-related macular degeneration (AMD) will develop geographic atrophy (GA), which refers to patches or regions of the retina where cells waste away and die (atrophy). Sometimes these regions of atrophy look like a map to the doctor who is examining the retina, hence the term geographic atrophy.
The immune system is designed to fight off infections. To do this, it must be able to tell the difference between our own cells (and leave them alone) versus invading bacteria or viruses (and attack them). As we age, our cells are altered by “oxidative” damage and accumulation of debris (i.e environmental toxins like sun, chemicals, tobacco smoke, and other pollution) , which can cause the immune system to attack its own cells.
Age-related macular degeneration (AMD) is caused by a number of genetic and environmental factors.
Genes may be one way to lower the risk of AMD, if researchers can block or replace signals from genes that trigger disease, and promote the survival and integrity of the retinal pigment epithelium (RPE) cells when they encounter oxidative stress from aging and other causes.
Diet and Nutrition
Research shows there is a strong link between dietary patterns and age-related macular degeneration (AMD).
People with diets that are elevated in fat, cholesterol and high glycemic index foods, and low in antioxidants and green leafy vegetables may be more likely to develop AMD.
Unlike skin and other parts of the human body, the nerve cells of the eyes do not, for the most part, regrow or regenerate after damage has occurred. However, there is new hope. Work is moving forward to regenerate and reconnect the eye’s retinal cells that have been damaged by age-related macular degeneration (AMD), and to restore the underlying retinal pigment epithelium (RPE) cells that provides its nourishment and support.
Innovative Treatment Approaches
One day, we may be able to detect signs that age-related macular degeneration (AMD) is developing and take early steps to defend against it. Macular Degeneration Research is funding research into unique ways to protect the retinal pigment epithelium (RPE) and retina at earlier stages, before damage to sight has occurred.
The red cone photoreceptor:
Cone photoreceptors, like the one shown in red, are responsible for high-definition central vision, the kind lost in macular degeneration. (Courtesy of Mrinalini Hoon, PhD, and Raunak Sinha, PhD, University of Wisconsin-Madison).