Researchers at the University of Sheffield have created the complex hair cells and the neurons needed for hearing from human stem cells.
They found they could encourage stem cells from the inner ears of human foetuses to grow into these highly specialised hearing cells.
The scientists hope they will eventually be able to use the cells to perform cell transplants in deaf patients to replace the hair cells and neurons that are damaged in a form of deafness known as sensorineural hearing loss.
Sensorineural hearing loss one of the most common forms of deafness, accounting for 90 per cent of cases and affecting more than 6 million people.
The only treatment currently available is cochlear implants, but these electronic devices can never restore the full range of hearing.
Dr Marcelo Rivolta, who led the research, said: “The hair cells and neurons that give us the ability to hear are only produced during the embryonic stage of development. Once they are damaged or lost, they do not regenerate.
“There is a clear need for a therapy that can regenerate or replace these hair cells and neurons when they are damaged.”
The researchers obtained stem cells from the cochleae of aborted foetuses. The stem cells that have the capability to be transformed into the auditory apparatus needed for hearing disappear rapidly after birth, which is why our bodies cannot repair any damage.
Dr Rivolta and his team found they were able to grow these stem cells in the laboratory and encourage them to turn into hair cells.
He is now conducting tests in animals to see if transplanting these cells will be able to restore hearing. He also hopes it will be possible to grow these cells from other sources of stem cells such as bone marrow
He warned it could be at least 10 years before human patients could receive stem cell transplants to restore their own hearing.
But he added: “In the shorter term, these cells also provide us with a very good model for studying the development of human hearing and the effect that new drug treatments may have on them.”
Hair cells are responsible for turning sound into electrical impulses that can be carried to the brain. Tiny hair like growths from the surface of the cell move when sound waves pass over them and this movement sends small electrical signals along the nerves to the brain.
Dr Ralphe Holme, director of biomedical research for the Royal National Institute for Deaf People, said: “There are currently no treatments to restore permanent hearing loss so this has the potential to make a difference to millions of deaf people.”