Promising new treatment restores sight to the blind

Teresa Tanoos's picture
New treatment could restore sight to those with blinding diseases
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Researchers at UC Berkeley have developed an easier and more effective treatment to help restore sight, offering new hope for people with blinding diseases, including macular degeneration and retinitis pigmentosa.

The treatment involves the insertion of genes into eye cells, which can significantly expand gene therapy to help restore sight to patients who are going blind due to diseases ranging from inherited defects to degenerative illnesses of old age, like macular degeneration.

And there’s more good news.

Unlike current procedures, this new treatment doesn’t require invasive surgery. Instead, it is quick and non-invasive, delivering normal genes to hard-to-reach eye cells throughout the entire retina.

Over the last six years, great strides have been made in the successful treatment of inherited eye disease by injecting a virus with a normal gene directly into the retina with a defective gene. Despite the invasive procedure, however, the virus with the normal gene was not capable of reaching all cells in the retina that needed fixing.

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"Sticking a needle through the retina and injecting the engineered virus behind the retina is a risky surgical procedure," said David Schaffer, Director of the Berkeley Stem Cell Center at UC Berkeley.

"But doctors had no choice, because none of the gene delivery viruses can travel all the way through the back of the eye to reach the photoreceptors – the light sensitive cells that need the therapeutic gene,” Schaffer added.

"Building upon 14 years of research, we have now created a virus that you just inject into the liquid vitreous humor inside the eye, and it delivers genes to a very difficult-to-reach population of delicate cells in a way that is surgically non-invasive and safe,” Schaffer explained. "It's a 15-minute procedure, and you can likely go home that day."

The engineered virus works far better than current treatments in rodent models of two human degenerative eye diseases. Plus, it can penetrate photoreceptor cells in monkeys' eyes, which are similar to the eyes of humans.

Schaffer said he and his team are now collaborating with physicians to identify the patients most likely to benefit from this gene delivery technique – and, after some preclinical development, they hope soon to move forward with clinical trials.

Schaffer and John Flannery, UC Berkeley professor of molecular and cell biology and of optometry, along with colleagues from UC Berkeley's Helen Wills Neuroscience Institute and the Flaum Eye Institute at the University of Rochester in New York, published the results of their study on June 12 in the journal Science Translational Medicine.

SOURCE: Sci Transl Med 12 June 12, 2013: Vol. 5, Issue 189, p. 189ra76 (DOI: 10.1126/scitranslmed.3005708)

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