Test-tube 'hair cells' may treat deafness

Treating deafness in the elderly may soon be possible after scientists in America succeeded in growing the cells in the ear involved in detecting sound.

The researchers grew fully mature "hair cells" - found only in the inner chamber of the ear - by culturing stem cells from the embryo of a mouse in a test tube.

Impaired hearing in the elderly was often caused by the loss of hair cells, particularly those that detected high frequencies, so a method of replacing them would offer the possibility of treating progressive deafness, said Professor Stefan Heller of Harvard Medical School in Boston, Massachusetts.

The study, published in the Proceedings of the National Academy of Sciences, showed that embryonic stem cells grown in a culture medium rich in growth factors found in the inner ear could trigger development into specialised cells of the inner ear.

Professor Heller said he hoped the research would be replicated with human stem cellsto develop hair cells for a tissue transplant into the ear of someone who was deaf.