Eye drops could help cure blindness.
So says new research that suggests cholesterol-lowering drugs given in the form of eye drops have cured macular degeneration in mice --- and could do the same for their human counterparts sometime soon.
Macular degeneration ranks as the main cause of blindness in U.S. adults aged 60 and over.
The disease affects cells in the eye's macula -- the central part of the eye that allows people to detect fine details - and destroys central vision in the process, according to data from the National Eye Institutes.
Currently, there's no way to restore vision lost from macular degeneration, although treatment can slow the loss of vision.
Previous studies found a link between cholesterol metabolism and age-related blindness. The accumulation of white blood cells that break down cholesterol, called macrophages, is often found in people with macular degeneration.
Macrophages as well may cause abnormal blood vessels to grow in the eye, leading to bleeding, scarring and blindness, according to the study, which was published in the April 2 issue of Cell Metabolism.
Researchers took macrophages from old mice and humans with macular degeneration and discovered they had low levels of ABCA1, a protein that transports cholesterol from cells.
The researchers then worked to activate receptors that would affect ABCA1 expression in mice, with the help of cholesterol-lowering drugs.
They tested two types of drugs, finding both medications increased ABCA1 levels and improved cholesterol transport in macrophages --- thereby reducing the growth of new blood vessels.
"Our increased understanding of cholesterol's role in the growth of ocular blood vessels helped us identify therapeutically modifiable pathways, opening up avenues for new treatments that may help us prevent blindness caused by macular degeneration," said senior study author Dr. Rajendra Apte, a professor of ophthalmology and visual sciences at the Washington University School of Medicine in St. Louis.