Ear gel to stop you losing your hearing

AGEL injected into the ear could prevent hearing loss caused by loud noise, infections and even chemotherapy. The gel contains a compound that blocks key enzymes linked to hearing loss.

Early studies suggest that if the gel is injected within three days of sudden deafness caused by loud noise it can stop this becoming permanent. The gel, known as AM-111, is designed to treat sensorineural hearing loss, the most common type of permanent hearing loss, affecting thousands in the UK.

It occurs when there is damage to nerve pathways or to tiny hair cells responsible for transferring sound signals from the ear to the brain — these hair cells are found in a coiled structure in the inner ear, known as the cochlea.

Damage can gradually develop as a result of infection or inflammation, as a side-effect of chemotherapy, or as part of the ageing process — but it can also occur suddenly as a result of exposure to loud noises.

Long or repeated exposure to sounds at 85 decibels or more (comparable to the sound of a lawnmower or heavy traffic, for example) can cause hearing loss as the hair cells are overstimulated and damaged.

When damaged, the hair cells release an enzyme called JNK, which triggers gene activity and chemical reactions that effectively destroy the hair cells and nerves, permanently damaging hearing.

These cells can’t repair themselves or grow back. While this sometimes causes immediate hearing loss, the processes activated by JNK can also continue over the hours and days that follow exposure to the loud noise. Researchers believe this offers a window for treatment to stop the action of the enzyme.

The gel is injected through the eardrum, where it works its way into the inner ear and cochlea.

Here, it binds to the JNK enzyme, deactivating it. The gel is gradually broken down by the body.

A study on guinea pigs showed that those given the injection after loss of hearing had much less damage and better hearing after a few days compared with those treated with a placebo, according to the journal The Laryngoscope.

An initial study involving 210 patients in Germany with sudden hearing loss also found more pronounced improvements in those given the gel.

Developed by Swiss company Auris Medical, the gel is now being tested specifically in patients who suddenly lose hearing after exposure to loud noise.

The idea is that if it’s shown to be effective, it could help treat other cases of sensorineural hearing loss, too.

More than 250 people are taking part in a trial across Europe, testing the effects of a single injection of AM-111. Patients will receive either the gel jab (two doses are being tested) or a placebo within 72 hours of reporting hearing loss, regardless of the cause. A similar study on U.S. patients will begin next year.

Commenting on the technology, Andrew McCombe, a consultant ear, nose and throat surgeon at Frimley Park Hospital, Surrey, said: ‘The elegant and interesting thing is that the drug is injected through the tympanic membrane [eardrum] into the middle ear space, where it can diffuse through into the inner ear to have its therapeutic effect.’

HE ADDS: ‘ This means it will get directly to the place where it is needed, without the need for oral or intravenous administration, which might have other — possibly unwanted — effects in the body.

‘It will be interesting to see what the results show.’

MEANWHILE, older people with impaired hearing may have shorter lives than those with normal hearing.

U.S. researchers analysed data from around 1,700 over-70s who had hearing tests. When monitored over subsequent years, results suggested those who scored badly on hearing tests were 21 to 39 per cent more likely to die in the years that followed, according to the study in the journal JAMA OtolaryngologyHead & Neck Surgery.

People with hearing loss tend to have other health issues and poorer physical health in general.