Scientists carried healthy DNA into the ears of profoundly deaf rodents using a harmless virus
A cure for deafness could be on the horizon after a new gene therapy technique restored “near normal” hearing in mice.
Scientists carried healthy DNA into the ears of profoundly deaf rodents using a harmless virus.
This enabled them to pick up noise as quiet as 25 decibels – the equivalent of a whisper.
They were suffering a condition similar to hereditary human deafness – raising hopes the technique could be used on patients.
Dr Jeffrey Holt, of Harvard medical School in Boston, said: “This is a landmark study.
The research was carried out at Harvard Medical School, Boston, Massachusetts, New England (Image: Rex)
“Here we show, for the first time, that by delivering the correct gene sequence to a large number of sensory cells in the ear, we can restore both hearing and balance to near-normal levels.”
The breakthrough described in two papers in Nature Biotechnology could lead to treatments for genetic diseases of the inner ear which affect an estimated 125 million people worldwide.
Previous viruses have only been able to penetrate the cells of the inner ear – or cochlea.
But a new synthetic vector called Anc80 safely transferred genes to the hard-to-reach outer hair cells when introduced into the cochlea.
These tune the responses of ‘inner hair cells’ to sound waves.
The scientists made the breakthrough using gene therapy (Image: Getty)
In many cases of genetic hearing loss delivery of genes to both outer and inner hair cells is needed to confer normal hearing ability.
Dr Konstantina Stankovic, of Massachusetts Eye and Ear, said: “We have shown Anc80 works remarkably well in terms of infecting cells of interest in the inner ear.
“With more than 100 genes already known to cause deafness in humans, there are many patients who may eventually benefit from this technology.”
Safety studies found the injection procedure had no adverse effects.
In the second paper researchers used the same viral vector to treat mice carrying a mutated gene responsible for Usher syndrome type IC – a childhood genetic disease that causes deafness, problems with balance and blindness.