The Better to See you With: One Grade Improvements for Cataracts

Cataracts effect over half of the United States population over 70 years old. However, this condition is not restricted to humans, many animals also suffer from cataracts. Often an age related disorder, cataracts may occur in one eye or both resulting from a variety of causes including: environmental exposure (excessive sunlight), certain behaviors (regularly consuming alcohol), and as a side effect of certain diseases (like diabetes). Cataracts are caused by protein aggregations within the eye which lead to cloudiness and blurry vision. This may have a huge impact on the quality of life of an individual. Those with cataracts may have a hard time driving at night, double vision, faded colors, and many changes in prescription of eyeglasses. Cataracts are rated on a scale of 1-4 as the condition becomes increasingly worse. Prior to a study by Gestwicki, the only treatment was surgery. While surgery has high success rate, healing can take as long as 8 weeks. Additionally, surgery may be costly, some individuals may not be able to afford this treatment.

Chaperone proteins CRYAA and CRYAB generally keep proteins which are misfolded or otherwise dysfunctional from aggregating allowing for clear vision. However, as humans age the sheer number of misfolded and damaged proteins begin to overwhelm these proteins. These proteins are really unique-they are undruggable. Boosting the function of these proteins would seem like a great target to help prevent aggregation of the increasing numbers of damaged proteins; however, the activity of these proteins are immeasurable.

In a type of hereditary cataract, there is a mutation of CRYAB which increases the melting point of the protein rendering it dysfunctional. Gestwicki's research team tested many molecules, finally settling on compound 29. This is a steroid normally found in the bloodstream which has the ability to bind to the mutant CRYAB and lower the melting point, thereby restoring function. Mice receiving this steroid in the form of an eye drop experienced a one-grade improvement in as little as a few weeks.

This treatment causes significant improvements over a short time scale. Eye drops may be a cheaper and more accessible option for many patients and do not have the long recovery time associated with surgery. While more research is needed before human trials are begun, this is a promising treatment to restore eye sight for many seniors who may be coping with many challenges every day stemming from reduced eye sight.

Sources:

http://news.sciencemag.org/health/2015/11/steroid-eye-drops-reverse-cataracts-mice

https://nei.nih.gov/health/cataract/cataract_facts

http://www.eyecareforanimals.com/conditions/cataracts/