US researchers develop a new eye drop cataract treatment

Posted on 17 Aug 2016 by Tim Brown
A cataract in a human eye which could be a candidate for this new cataract treatment - image courtesy of By Rakesh Ahuja, MD.
A cataract in a human eye which could be a candidate for this new cataract treatment - image courtesy of By Rakesh Ahuja, MD.

Researchers from the University of California, San Diego, have developed a new cataract treatment that can effectively dissolve cataracts.

The university researchers have discovered a promising alternative to cataract surgery – an eye drop cataract treatment, which has shown to effectively reverse cataracts during animal testing.

The findings of the clinical testing were published in the journal Nature, which showed that the drug used by the University of California researchers, which was based on the naturally-occurring steroid lanosterol, significantly decreased preformed protein aggregates both in vitro and in cell-transfection experiments.

The studies featured in Nature also showed that lanosterol treatment could reduce cataract severity and increase transparency in dissected rabbit cataractous lenses in vitro and cataract surgery in vivo in dogs.

Cataract treatment study

Lanosterol re-dissolved pre-formed amyloid-like fibrils of crystallin proteins - effectively disolving the cataracts - image courtesy of Nature
Lanosterol re-dissolved pre-formed amyloid-like fibrils of crystallin proteins – effectively disolving the cataracts – image courtesy of Nature.

The University of California, San Diego, researchers began their work by focusing on the cases of three children who had a severe cataract condition that ran in their family.

The scientists sequenced the children’s genomes and identified a genetic mutation that interfered with the production of lanosterol, a steroid which occurs naturally in the body.

From this identification the researchers decided to test whether lanosterol might have the ability to prevent or even eliminate cataracts.

The university researchers first tested the new drug in lab cultures, then in the cataract lenses of rabbits, and finally on 7 dogs from 3 different breeds who were suffering from adult-onset cataracts.

The dogs treatment involved each of the 7 animals being seated and injected with lanosterol (100mg) loaded nanoparticles into the vitreous cavity of their eyes. The treatment eyes then received lanosterol in topical eye drops, one drop three times a day for 6 weeks.

The dogs who received the treatment showed notable improvement in their cataracts, graded on a scale from 0 (no cataract) to 3 (extensive opacity of the entire lens).

Before testing on the dogs, the University of California researchers tested their lanosterol-based eye drops on rabbits, and after six days all but two of the 13 animals had gone from having severe cataracts to mild cataracts or no cataracts at all.

Potential lanosterol use for human cataract treatment

While the lanosterol-based eye drops have yet to be tested on humans, the success of the studies on animals has prompted J Fielding Hejtmancik of the Ophthalmic Genetics and Visual Function Branch of the National Eye Institute to emphasise the potential of the new eye drops in future eye care use for humans.

Hejtmancik suggested the research could lead to non-surgical prevention and treatment of cataracts, with his praise of the new lanosterol-based eye drops featuring in commentary which accompanied the study published in Nature.

“The potential for this finding to be translated into the first practical pharmacological prevention, or even treatment, of human cataracts could not come at a more opportune time.”

One of the authors of the study which produced the ground-breaking eye drop, Professor of Ophthalmology and Chief of Ophthalmic genetics at University of California, Dr Kang Zhang, said that before testing could begin on humans the research team will need to check the toxicity of lanosterol, even though it is a product of our own body, and subsequently formulate the lanosterol-based drug as the most efficient eye drop for a human trial.

Addressing the potential for the eye drops use in human eye care during a Nature podcast, Zhang said he and his colleagues hope to begin human trials within a year.

 

Top image by Rakesh Ahuja, MD (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA 2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/2.5-2.0-1.0)], via Wikimedia Commons.