FFB Written Articles » Usher Syndrome
Cell-Based Treatment Preserves Vision in Usher Syndrome Model
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A research team funded by the Foundation Fighting Blindness has used cell transplantation to restore vision in a mouse model of Usher syndrome type 2A (USH2A), a leading cause of combined deafness and blindness in humans. Never before has a cell-based treatment been used to save vision in an Usher syndrome study, in large part because no other Usher syndrome animal models have exhibited vision loss or retinal degeneration. The advancement is a critical step forward in developing a vision treatment for humans with the condition. Ray Lund, Ph.D., of the Casey Eye Institute, Oregon Health & Science University and lead investigator of the study, says that the USH 2A animal model exhibits slow progression of retinal degeneration, though deterioration of vision is much faster. He and his team are strongly encouraged by the fact that their cell-based treatment preserved vision in the mice well before the time their retinas would normally degenerate. Dr. Lund says that the early preservation of vision shows that the treatment might be effective as a preventive approach for humans. David Gamm, M.D., Ph.D., of the University of Wisconsin-Madison and a scientist on the team, notes that the new USH2A model of retinal degeneration is helping researchers better understand how cell-based therapies work for a variety of retinal degenerative diseases including different forms of retinitis pigmentosa. “By using different animal models with varying disease pathways, we can better understand how these cell-based therapies are saving and restoring vision,” says Dr. Gamm. He adds that the neural stem cells used in their USH2A study are also showing promise as treatments for diseases of the central nervous system including Parkinson’s disease and amyotrophic lateral sclerosis (ALS). The USH2A mouse model was developed by Tiansen Li, Ph.D., Harvard Medical School, Massachusetts Eye & Ear Infirmary. It is the first Usher syndrome model in which the animal develops both vision and hearing loss. Dr. Li and his colleagues developed the model by disrupting, or “knocking out,” both copies of the animal’s USH2A gene. The normal USH2A gene leads to the production of proteins that are necessary for cilia — tiny hair-like structures — to function properly in the retina’s photoreceptors and the cochlea of the inner ear. Cilia transport proteins and nutritional substances within photoreceptors to keep them healthy and functioning properly. Results of the USH2A study were published in the December 3, 2009 online issue of the journal Investigative Ophthalmology & Visual Science. |
