Scientists at Sheffield university have taken an important step towards using stem cells to restore hearing to deaf people.
Their research shows for the first time how embryonic stem cells can be converted into the specialist cells we rely on for hearing. These sensory hair cells and auditory neurons, as they are known, cannot be regenerated in adults using existing medical technology; once they are damaged, hearing loss is permanent.
The long-term aim is to treat deafness by transplanting new auditory cells, generated from stem cells, into people who have lost their own.
“We have found the recipe to persuade embryonic stem cells, which can become any cell in the body, to become auditory cells,” says Marcelo Rivolta, who has led the Sheffield project for the past five years. “Our lab studies have shown that these cells behave and function just like their counterparts in our developing ears.”
The research started by studying cells from the developing ears of aborted human foetuses (around 10 weeks old) and then applied the findings to embryonic stem cells (which originate in early embryos just a few days old). The next step will be to graft the specialist auditory cells into deaf strains of laboratory animals.
The research – funded by the charities Royal National Institute for Deaf People and Deafness Research UK – is published online by the journal Stem Cells and will be discussed at next week’s UK National Stem Cell conference in Oxford.
Ralph Holme, director of biomedical research at RNID, says: “Stem cell therapy for hearing loss is still some years away but this research is incredibly promising and opens up exciting possibilities by bringing us closer to restoring hearing in the future.”
A more immediate application will be for research into deafness. “We have now an experimental system to study genes and drugs in a human context,” says Dr Rivolta, who is originally from Argentina.
“In addition to the future potential for restoring hearing with stem cell therapy, the recent research success means that we may now have better ways to test the efficacy and toxicity of new drugs on auditory cells,” adds Vivienne Michael, chief executive of Deafness Research UK.