New 'deafness cure' hope from stem cell research

A CURE for deafness moved a step closer yesterday as scientists revealed a major breakthrough in stem cell research.

The team of researchers has managed to turn early stem cells into components that could be used to restore hearing.

Treatments for deafness could still be at least ten years away and still need to be tested in animals. But the cells could also be used more immediately to investigate the causes of deafness and to test new drugs.

The ground-breaking work, funded by RNID and Deafness Research UK, will be presented at a major stem cell conference in Oxford next week.

The scientists, from Sheffield University, were able to direct foetal stem cells to become early versions of the sensory hair cells and neurons that are essential for hearing.

Lead researcher Dr Marcelo Rivolta said: "The potential of stem cells is very exciting.

"We have now an experimental system to study genes and drugs in a human context.

"These cells would help us to develop the technologies needed to deliver them into damaged tissues, such as the cochlea, in order to restore the different cell types. This should facilitate the development of a stem cell treatment for deafness."

Stem cells are immature cells that can develop along a number of different pathways to become different types of tissue. Those used in the new research were taken from the developing cochleas of discarded human foetuses aged nine to 11 weeks.

Dr Rivolta's team, writing in the journal Stem Cells, grew the cells in the laboratory and exposed them to a cocktail of chemicals. More than half displayed the electrical and physical features of sensory hair cells – which turn sound waves into nerve impulses. Other cells showed the properties of auditory neurons – which transmit hearing messages to the brain.

Dr Rivolta said being able to make neuron and hair cells was important because these cells were usually only created in the womb, meaning when they are lost or damaged they are gone forever.

"The adult human body cannot regenerate these auditory cells," he said. "The next step in our research is to explore how these cells react when grafted into animal models. In the long term we all hope they may offer a route to restoring hearing for patients."

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