A new discovery by research scientists has identified the role cholesterol plays in contributing to age-related macular degeneration, AMD, the leading cause of blindness in older adults.
Age-Related Macular Degeneration
According to Research to Prevent Blindness , an estimated 1.75 million Americans age 40 and older have diminished vision due to AMD, and that number is anticipated to increase to 3 million in 2020. Early AMD is more common, but late AMD presents the most problems with sight.
Abnormalities in the macula, a portion of the retina, result in early symptoms of blurriness of vision that can progress to blind spots. Early diagnosis is important because early-stage age-related macular degeneration can progress to late-stage AMD. Fortunately, progression is slow, but vision abnormalities caused by this condition are irreversible.
Impaired Cholesterol Out-Flow from Eye Promotes Age-Related Macular Degeneration
Research published yesterday in Cell Metabolism explained how its study authors determined that the specimens of mice and human eyes they studied had in common reduced levels of a protein, ABCA1, responsible for the transport of cholesterol out of the eye.
With this information, researchers theorized that a drug that would activate the production of ABCA1 would result in lowered eye cholesterol. Two drugs have been developed, one an eye drop or injection and one that is injectable only. A Liver X Receptor agonist, LXR, is available as drops or an injection and the second drug, called a microRNA — 33 inhibitor, is an injectable-only drug.
The slowed production of ABCA1 has been identified in the research as the underlying cause of wet AMD, the form in which extra blood vessels form under the macula, leaking blood and fluid into the retina.
Both drugs are in the early stages of research and development, but it is hoped that continued study will prove the drugs to be both safe and effective in the treatment of AMD. The Telegraph reported that researchers hope to be able to begin clinical trials on these promising drugs, or ones like them, within five years.
Current AMD Treatment Versus Projected Treatment in the Future
Current treatment for wet age-related macular degeneration, the less common but more vision-damaging of AMD types, is monthly eye injections for an extended period of time. These treatments are intended to prevent worsening of the wet AMD and related vision problems and loss.
As to the potential for successful treatments of wet AMD in the future, Rajendra S. Apte , M.D., Ph.D., explained to the Telegraph that the hope is that the drug that promotes the flow of extra cholesterol from the eyes may be incorporated into anti-cholesterol medications used for the heart.
