Eye Drops Using Newly Identified Chemical Could Clear up Cataracts
A chemical that could potentially be used in eye drops to reverse cataracts, the leading cause of blindness, has been identified by a team of scientists from UC San Francisco (UCSF), the University of Michigan (U-M), and Washington University in St. Louis (WUSTL). The study, published November 5th 2015 in Science, reports that the newly identified compound is the first that is soluble enough to potentially form the basis of a practical eye-drop medication for cataracts.
A release from UCSF explains that cataracts, identified as a “priority eye disease” by the World Health Organization, are caused when the lenses of the eyes lose their transparency. The condition affects affect more than 20 million people worldwide. Although cataracts can be successfully removed with surgery, this approach is expensive. Also, most people blinded by severe cataracts in developing countries go untreated.
Cataracts are primarily a disease of aging. As is seen in neurodegenerative conditions such as Alzheimer’s disease and Parkinson’s disease, a hallmark of the condition is the misfolding and clumping together of crucial proteins. In the case of cataracts, the affected proteins are known as crystallins.
Crystallins are the major component of fiber cells, which form the eyes’ lenses, and the unique properties of these cells make them particularly susceptible to damage, said Jason Gestwicki, PhD, associate professor of pharmaceutical chemistry at UCSF and co-senior author of a paper on the new research, most of which was undertaken in Gestwicki’s laboratory at the U-M Life Sciences Institute.
The release quotes Gestwicki, who has continued his work on cataracts at UCSF, where he joined the faculty about two years ago, as saying, “Shortly after you’re born, all the fiber cells in the eye lose the ability to make new proteins, or to discard old proteins. So the crystallins you have in your eye as an adult are the same as those you’re born with.”
In order for our lenses to function well, this permanent, finite reservoir of crystallins must maintain both the transparency of fiber cells and their flexibility, as the eyes’ muscles constantly stretch and relax the lens to allow us to focus on objects at different distances.
The crystallins accomplish these duties with the help of aptly named proteins known as chaperones, which act “kind of like antifreeze,” Gestwicki said, “keeping crystallins soluble in a delicate equilibrium that’s in place for decades and decades.”