LONDON (Reuters) - Stem cells may help deaf people hear again, according to
early stage research by British scientists.

A team at the University of Sheffield said on Thursday they had discovered how
to turn stem cells into ones that behave like sensory hair cells or auditory
neurons, which could then be surgically inserted into the ear to restore lost
hearing.

Lead researcher Marcelo Rivolta said the approach, which is being tested on
animals, held significant potential but was a long way from being offered to
patients.

"It will take several years before we are in a position to start doing human
trials," he said in a telephone interview.

The cells in the ear that detect sound are created only in the womb, which means
there is no way to repair them once they have been damaged, resulting in
permanent hearing loss.

Using stem cells -- master cells that produce all the body's tissues and organs
-- to generate these cell types in the laboratory could change that
dramatically.

Rivolta's research parallels more advanced work on the eye by another group of
British-based scientists, who plan to use stem cells to treat age-related
macular degeneration, a common cause of blindness, in clinical tests starting in
2010 or 2011.

Doctors hope one day to use stem cells to treat a wide range of diseases such as
Parkinson's, diabetes and cancer. But localized approaches in the eye or ear may
be a promising first step, since fewer cells are involved.

Rivolta and colleagues used foetal stem cells in their work, although they are
also investigating the potential of both embryonic and adult stem cells.

Laboratory studies showed that the new cells derived from foetal tissue behaved
and functioned just like their normal ones in developing ears.

"This research is incredibly promising and opens up exciting possibilities by
bringing us closer to restoring hearing in the future," said Ralph Holme,
director of biomedical research at the Royal National Institute for Deaf People,
which helped fund the work.

Details of their research were published in the journal Stem Cells and are due
to be presented at a stem cells conference in Oxford next week.