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Gene delivery system shows promise in vision loss prevention

IANS | New York |

Researchers have developed gene- carrying nanoparticles that home in on target cells and prevent vision loss in animal models of an inherited eye disease which is also one of the most common causes of blindness in children.

Though this research, published in the journal Molecular Therapy – Nucleic Acids, focused on the form of the disease called Leber congenital amaurosis 2, or LCA2, the scientists and engineers involved in the study believe the technology holds promise for other forms of LCA as well as other inherited diseases that lead to severe vision loss or blindness.

"We believe this technology can deliver almost any type of gene to tackle inherited visual disorders," said lead researcher Zheng-Rong Lu, Professor at Case Western Reserve University in Cleveland, Ohio, US. 

Those with LAC2 carry a mutated RPE65 gene and suffer from profound vision loss from birth. 

The mutated gene fails to produce RPE65 protein in the retinal pigment epithelium (RPE), a cell layer critical for protecting photoreceptors (rods and cones). 

The protein is an essential constituent of the visual cycle that converts light to electrical signals to the brain.

Lu and colleagues designed a lipid-based nanoparticle called ECO to deliver healthy RPE65 genes to RPE cells.

"The promise of this technology is it localises the drug to the photoreceptor cells, sparing the liver and kidney from exposure," Krzysztof Palczewski from the Case Western Reserve School of Medicine said. 

Following injection into the retina of mice, the researchers could see fluorescent green concentrating in RPE cells. 

Testing showed a significant increase in light-induced electrical activity from the eyes to the brain, indicating the rods and cones were operating as they should in the visual cycle.

The therapeutic effect lasted 120 days in treated mice and no improvements were observed in untreated mice.

"This work is important beyond one disease," Palczewski said.

"The loss of photoreceptor cells affects virtually all of us," Palczewski noted.