Hearing Nerves Rebuilt in Gerbils to Treat Deafness



Treating deafness in humans has taken a huge step forward after stem cells were used to make deaf gerbils ‘hear again’, according to a recent journal.

Researchers at the University of Sheffield say they have made a huge development in combatting deafness after they restored the hearing in animals for the very first time.

Professor Dave Moore, the Senior Research Scientist of the Institute of Hearing Research in Nottingham, told the BBC: “It is a big moment; it really is a major development.”

Gerbils were used as part of the experiment because it is reported that they hear a similar range of sounds to people, unlike mice that hear higher-pitched noises.

What is the science?

People hear everything around them when the ear converts sound waves into electrical signals. It happens deep inside the ear when vibrations move the tiny hairs. This movement then creates a signal which is then passed onto the brain.

The hearing in gerbils was partially improved when nerves in the ear, which pass the sound stimulus to the brain, were rebuilt.

Around 10% of people with profound hearing loss have damaged nerve cells which struggle to pick up the electrical signal. The aim was to replace those cells, otherwise called spiral ganglion neurons, with new ones.

What happened?

Stem cells were used from a human embryo. A ‘chemical soup’ was added to convert them into hair cells and this was then injected into the inner ears of 18 deaf gerbils. The animals’ hearing was measured using brainwaves and it improved over a 10 week period.

On average, 45% of their hearing range was restored. The results have been likened to not being able to hear a truck in the street, to hearing a conversation proficiently. Some of the gerbils regained up to 90% of their hearing.

Can it work on humans?

Obviously getting the same results for humans is still a distant prospect but it is still encouraging to see stem cell development edging that little bit closer to tackling deafness.

It is important to note that restoring nerves in the ear may not help everyone with a hearing loss. Injecting the converted stem cells into the ear will also not be an easy task, as they need to be in the exact place and face the right direction.

Dr Ralph Holme, Head of Biomedical Research for the charity Action on Hearing Loss, the trading name of the Royal National Institute for Deaf People (RNID), said: “The research is tremendously encouraging and gives us real hope that it will be possible to fix the actual cause of some types of hearing loss in the future.

“For the millions of people for whom hearing loss is eroding their quality of life, this can’t come soon enough.”

However, Professor Moore stressed that using stem cells to repair ear hairs is “almost an impossible task” and that repeating the feat in people will be a “really formidable undertaking.”