Cure for deafness a reality as scientists make animals hear again… and promise first human patients will be treated in a 'few years'
Scientists used injections of millions of stem cells to successfully treat profoundly deaf gerbilsOn average, hearing was restored by almost 50% within just a few weeksBut, in some cases, it returned to near perfect levels
19:50 GMT, 12 September 2012
Deaf animals have been made to hear again, in a breakthrough that brings hope to millions.
Sheffield University scientists used injections of millions of stem cells to successfully treat profoundly deaf gerbils.
On average, hearing was restored by almost 50 per cent within just a few weeks. But, in some cases, it returned to near perfect levels.
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Restored hearing: Deaf animals have been made to hear again, in a breakthrough that brings hope to millions
The work is still at an early stage but it raises the prospect of people going from being unable hear a lorry thundering past them on the street to being able take part in everyday conversations once more.
In time, up to 90 per cent of the ten million Britons who are deaf and hard of hearing could be helped, including many for whom hearing aids and other devices provide no benefit.
Dr Ralph Holme, of charity Action on Hearing Loss, formerly known as the Royal National Institute for Deaf People, said the research gives ‘real hope’ for the future.
He added: ‘For the millions of people for whom hearing loss is eroding their quality of life, this can’t come soon enough.’
One in six Britons suffers from some form of hearing loss, with 70 per cent of over 70 year-olds and 40 per cent of those 50-plus affected.
However, it is not just a problem of the old, with one in three sufferers of working age.
The research, which was part-funded by Action on Hearing Loss, involves a type of deafness called auditory neuropathy.
It accounts for up to 15 per cent of cases and it caused by age, genes, noise or illness damaging the delicate nerve cells in the inner ear that transmit electrical signals to the brain, where they are decoded as sounds.
There are no treatments in widespread use but the study, published in the journal Nature, suggests that embryonic stem cells hold the answer.
In the unborn baby, these ‘master cells’ cells are able to turn into the all the tissue types in the body and many researchers around the world see them as repair kit for dying, damaged and worn out parts of the adult body.
Scientists used gerbils were in their experiments because, unlike mice, they hear the same range of sounds as people
The Sheffield University researchers began by creating the combination of nutrients needed to turn the stem cells into immature versions of the cells damaged in auditory neuropathy.
They then injected tens of thousands of the cells into the inner ears of gerbils left profoundly deaf by a chemical treatment.
The animals’ hearing started to return after just four weeks and many showed substantial recovery after ten weeks.
Gerbils were used in the experiments because, unlike mice, they hear the same range of sounds as people.
Lead researcher Dr Marcelo Rivolta said he hopes to test the treatment on people within ‘a few years’.
But before they do this, they have determine how long the treatment lasts – and be confident that it is safe as well as effective.
Replacing the damaged nerve cells could help up to 15 per cent of those with hearing loss.
But if doctors could also replace the delicate hairs of the inner ear that convert vibrations into the electrical signals picked up by the nerve cells, up to 90 per cent of cases could be treated.
The researchers have had some success in making the hair cells but they are more difficult to insert properly into the ear.
Professor Walter Marcotti, one of the study’s authors, said the level of recovery seen could make an enormous difference to patients.
He told a news briefing in London: ‘It would mean going from being so deaf that you wouldn't be able to hear a lorry or truck in the street to the point where you would be able to hear a conversation in this room.’
The use of embryonic stem cells is controversial but it may eventually be possible to dispense with them an and use stem cells made from a sliver of the patient’s skin instead.
VIDEO: Scientists a step closer to deafness cure