SAN DIEGO, July 24 (UPI) -- Lanosterol, a molecule that makes cholesterol in human cells, may be the key to stopping and reversing the accumulation of proteins in the eye that cause cataracts.
Researchers made the discovery while investigating the genetic explanation for parents without cataracts having three of their four children develop them.
Cataracts causes cloudy vision, and sometimes blindness, as cells in the eye lens age and stretch. About 94 million people worldwide have cataracts.
"It would have a huge public health impact," Dr. Robert B. Bhisitkul, a professor of ophthalmology at the University of California San Francisco School of Medicine, told the L.A. Times. "Preventing or reversing cataracts with an eyedrop has been the Holy Grail in ophthalmology since the field began."
Lens cells in the eye migrate from the outside to the inside of the lens, stretching over time as they do. The farther they stretch, parts of the cell break down and disappear, causing cloudiness in vision. Lens cells also are filled with proteins called crystallins. The stretching, as well as other changes researchers said they don't yet fully understand, causes the proteins to clump together and obstruct vision.
Researchers in a University of California San Diego study, published in Nature, investigated the genetic explanation for a family with two parents, who are first cousins and do not have cataracts, who have three children with cataracts and one without.
The three children who have cataracts had two mutated copies of a gene that regulates lanosterol production, leading researchers to test whether lanosterol would clear up cataract-like crystalline proteins in human lens cells in a dish. When this was successful, researchers tested lanosterol in rabbit eye lenses with naturally occurring cataracts and gave dogs with cataracts shots of the molecule in the eye -- both of which improved lens clarity.
"We did everything we can do experimentally to show lanosterol can dissolve crystallin protein aggregations in cell cultures, in rabbit and dog cataract lenses," Kang Zhang, an ophthalmologist at the University of California San Diego, told PBS. "Obviously, we need to do more and our data need confirmation from other researchers. This is just a beginning."