Cholesterol-Lowering Drugs could Help Fight Blindness: Study

Data according to the Centers for Disease Control and Prevention states that more than 3.3 million Americans 40 years and older are either blind or have low vision. One of the leading causes of blindness and low vision in the U.S. is macular degeneration.

Focusing on this age-related blinding eye disease, a latest study states that the drug used to lower cholesterol levels may also be effective in treating macular degeneration, according to a news release.

The researchers have traced a common link between macular degeneration and atherosclerosis (thickening of the artery wall due to excess accumulation of cholesterol). They claim that both the problems have the same basic effect, the inability to eliminate the increase of fat and cholesterol.

Through the new study, the researchers explained how deposits of cholesterol cause macular degeneration and atherosclerosis. They even showed how blood vessels grow in a few cancers. The researchers state that the drugs taken by patients with atherosclerosis to reduce cholesterol levels can also be evaluated in those with macular degeneration.

This study basically focuses on macrophages that are the main immune cells involved in removing cholesterol and fat tissues. In macular degeneration, the cholesterol builds up along with age, after which the macrophages begin to break down.

In the "dry" form of macular degeneration, the doctors observed lipid deposits under the retina that became larger and more numerous, and slowly destroyed the central eye, thereby interfering with vision. Though the macrophages clear the fat deposits beneath the retina, there are possibilities that they inflate, with cholesterol creating an inflammatory process that leads to the formation of new blood vessels, which worsens the condition. These vessels are the "wet" form of the disease. Loss of vision from "wet" macular degeneration is due to bleeding and scar tissue formation.

Scientists identified a fat that is needed by the macrophages to clear fat and cholesterol. The study was conducted on mice and in human cells by Paul A. Cibis, Distinguished Professor of Ophthalmology and Visual Sciences, and his team.

They found that macrophages from both old mice and humans lacked the ABCA1 protein that carries cholesterol out of the cells. On treating the macrophages with a substance to re-establish ABCA1, they saw that the cells could remove the cholesterol, and the development of new blood cells was reduced.

"We were able to deliver the drug, called an LXR agonist, in eye drops," says first author Abdoulaye Sene, PhD, a post-doctoral fellow in the Apte lab. "And we found that we could reverse the macular degeneration in the eye of an old mouse. That's exciting because if we could use eye drops to deliver drugs that fight macular degeneration, we could focus therapy only on the eyes, and we likely could limit the side effects of drugs taken orally."

The study was published in the journal Cell Metabolism.