How a diet rich in antioxidants prevents macular degeneration
Washington, Aug 20 : A new study has revealed how a diet rich in antioxidants can
prevent the leading cause of age-related blindness in developed countries.
Researchers found a link between two processes in the retina that, in combination,
contribute to a disease called macular degeneration.
They found antioxidants disrupt the link and extend the lifetime of irreplaceable
photoreceptors and other retinal cells.
"The implication is that people at risk of macular degeneration could help prevent the
disease by consuming antioxidants," said Heidi Vollmer-Snarr, a Brigham Young University
chemist who earned a doctorate from Oxford and began work on this disease as a
postdoctoral researcher at Columbia.
People struck with the disease first lose central vision and temporarily adjust by
relying more on peripheral vision. Some eventually lose their vision entirely.
The study found a destructive synergy between the build-up of a compound called A2E and
damage to cellular 'power plants' called mitochondria. A2E is a natural byproduct of
cellular activity that, unlike other compounds, won't break down or be disposed by the
body.
A problem occurs when A2E encounters oxidative stress created by light exposure. In
these circumstances, A2E disrupts energy production in mitochondria.
The resulting energy shortage pulls the plug on daily cleaning and maintenance of
photoreceptors and another type of retinal cell.
The result is more A2E buildup, and the cycle of destruction hastens the death of these
vital visual cells, which are not replaced when they die.
The experiments performed with visual cells from rats, cows and humans showed that
antioxidants could completely counter the damage.
Seeing this process play out in the retina has given Vollmer-Snarr a novel idea for
attacking harmful growths in the body.
The strategy would involve delivering potentially disruptive compounds like A2E to the
target and then using light to trigger the damage.
The study appears online and is published in an issue of the Journal of Biological
Chemistry.
--ANI
