Gene Therapy for Retinitis Pigmentosa May Prevent Blindness
There is good news for the estimated 100,000 Americans who live with retinitis pigmentosa. Scientists have discovered how to deliver gene therapy directly to the cells affected by this eye disease and thus prevent blindness.
The discovery was the result of a collaborative effort between researchers at the University of Oklahoma Health Sciences Center and colleagues in Cleveland and Buffalo. Muna Naash, PhD, at the University of Oklahoma, said that “We hope the results of our study will be instrumental in generating a cure for the debilitating blindness associated with retinitis pigmentosa and other inherited and acquired retinal diseases.”
Retinitis pigmentosa is a term that refers to a group of inherited diseases that cause a degeneration of the retina, the part of the eye that captures images from the visual field. People who develop retinitis pigmentosa experience a gradual decline in their vision as the cells that capture the images (photoreceptor cells called rods and cones) die. Forms of retinitis pigmentosa and related diseases include Leber’s congenital amaurosis, Usher syndrome, and rod-cone disease, among others.
Symptoms of the disease depend on which cells are affected first. The Foundation Fighting Blindness notes that in most cases, the rods are impacted, which means individuals lose their peripheral and night vision. The cones are responsible for color and sharp central vision. Retinitis pigmentosa is usually first diagnosed during adolescence and young adulthood. Most people with the disease are legally blind by age 40.
Treatment for retinitis pigmentosa has focused on nutritional therapy, gene therapy, and implantable microchips. This latest study from the University of Oklahoma utilized nanoparticle technology to deliver genetic therapy inside cells of the retina.
The microscopic capsule created by scientists to transport the therapies has been very effective, arriving at the designated location in the eye within 15 minutes of delivery and quickly sending its contents to nearby cells. Robert E. Leonard, MD, an ophthalmologist at the Dean McGee Eye Institute called the work “an incredible breakthrough” and said that “outside of gene therapy, we are at a loss to be able to treat these patients.”
The study, which appears in the Journal of the Federation of American Societies for Experimental Biology (FASEB), is only the beginning for people with retinitis pigmentosa and others diseases. Already the discovery is being used to develop new treatments for macular degeneration, the leading cause of blindness in the United States. The microscopic capsule has also been tested in animals with the potential of treating diseases ranging from bladder cancer to diabetes.
Foundation Fighting Blindness
University of Oklahoma Health Sciences Center, news release June 10, 2010