Chemical clears cataracts in lab experiments with human lens tissue, mice

A company is developing the compound into an eye drop treatment for use in humans.
By Stephen Feller   |   Nov. 6, 2015 at 10:21 AM
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SAN FRANCISCO, Nov. 6 (UPI) -- A chemical was shown to clear cataracts in mice and human eye lens tissue in lab experiments, and researchers have already licensed it to a company to develop for human use.

The chemical is soluble enough to be used as an eye drop, researchers said, making for a far easier -- and cheaper -- method of treating the blinding condition, referred to as the "holy grail in ophthalmology."

Cataracts is a degenerative condition caused by the misfolding and clumping of proteins in the eye called crystallins, causing the eye's lens to lose transparency. Researchers have been searching for ways to prevent the proteins from clumping, and to dissipate the clumps, called amyloids, that have already formed.

In July, researchers at the University of California San Diego reported a chemical compound, lanosterol, cleared cataracts in rabbit and dog eye lenses. In that study, lanosterol had to be injected into the eye because it was not soluble enough to for an eye-drop formulation.

Researchers at the University of California San Francisco and the University of Michigan continued working with similar compounds, settling on compound 29, which in the lab dissolved amyloids that had already formed and stabilized crystallins, preventing them from clumping into amyloids.

In the new study, published in the journal Science, the researchers tested the compound on mice with mutations that made them predisposed to cataracts and mice with naturally developed age-related cataracts, finding that drops containing compound 29 improved transparency in the rodents' eye lenses. The same was seen in human lens tissue clouded by cataracts that had been removed during surgery.

The compound has been licensed by the University of Michigan to a company formed in the incubator program at UC San Francisco called ViewPoint Therapeutics to develop it for human use.

Based on the similarity between amyloids formed in the eye that cause cataracts and those formed in other parts of the body causing other degenerative diseases, Gestwicki thinks the research could lead to treatments for other diseases.

"If you look at an electron micrograph at the protein aggregates that cause cataracts, you'd be hard-pressed to tell them apart from those that cause Alzheimer's, Parkinson's, or Huntington's diseases," said Dr. Jason Gestwicki, an associate professor of pharmaceutical chemistry at UC San Francisco, in a press release. "By studying cataracts we've been able to benchmark our technologies and to show by proof-of-concept that these technologies could also be used in nervous system diseases, to lead us all the way from the first idea to a drug we can test in clinical trials."

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