In humans, damage to the inner ear by factors such as loud noise and certain types of drugs can lead to permanent hearing damage, tinnitus and even profound deafness. This deterioration is usually due to loss of the sensory ‘hair’ cells contained in the inner ear. These are extremely susceptible to both sound and injury and once they die, humans cannot grow more; yet in birds, these dead cells in the inner ear can regenerate throughout a bird’s lifetime to restore its hearing.
Current research led by Dr Nico Daudet, the inaugural Deafness Research UK UCL-EI Research Fellow, is investigating some of the signals and processes thought to be important for regeneration in chick inner ears. This may help researchers in the future to develop therapies to induce regeneration by cells of the inner ear and thereby reverse some forms of hearing loss in humans.
“In birds and cold-blooded vertebrates, hair cells spontaneously regenerate following tissue damage, but in mammals this ability has been lost. Why?” said Dr. Daudet. “Could we stimulate regeneration in the human ear to treat certain forms of deafness?” The human ear is one of the most sophisticated of all the organs of the body, so Dr Daudet’s area of research is very complex. The ultimate development of efficient and safe cures relies on a better understanding of the molecular signals involved in hair cell formation and regeneration, which is where this new research is focused.
Dr Daudet’s laboratory is investigating development and regeneration in the chick inner ear and, in particular, studying the function of a protein called Notch in the formation of hair cells. Notch is an important signalling protein that mediates communication between cells and is present in both mammals and birds.
In collaboration with scientists from around the world, including Dr Jennifer Stone (Seattle USA), Dr Daudet has shown that Notch plays a significant role by controlling the number of hair cells that are regenerated in the damaged chick ear. Signalling by Notch from one cell to another stops cells becoming hair cells and thus prevents too many forming. This is important, because in order for the regenerated hair cells to work properly, they must be present in an ordered pattern within the cochlea. We understand how the right number of cells is regenerated; however the nature of the signals triggering the regenerative response in the avian inner ear remains mysterious. Answering this question is one of the major objectives of Dr Daudet’s current research.
Vivienne Michael, Chief Executive of Deafness Research UK, said: “This groundbreaking research is essential for those with hearing problems. Looking into the hearing of birds is truly cutting-edge research and Dr Daudet’s work gives us real hope of a future regenerative cure for people with hearing impairments everywhere.”
There are many challenges still to overcome and even when the secrets of avian hearing have been unearthed, there will still be some way to go before the findings can be of benefit to humans, but raising the prospect of human hair cell regeneration offers one of the best hopes for a cure for long term deafness. Until then, Dr Daudet and his team continue to crack open the mysteries of the cochlea and inner ear regeneration.
Notes to editors
More info on Dr Nico Daudet http://www.ucl.ac.uk/ear/research/daudet
About Deafness Research UK
- Deafness Research UK is the country’s only charity dedicated to finding new cures, treatments and technologies for deaf, hard of hearing and other hearing impaired people.
- The charity supports high quality medical research into the prevention, diagnosis and treatment of all forms of hearing impairment including tinnitus.
- Deafness Research UK is entirely dependent on voluntary donations, gifts and personal legacies. You can donate online at www.deafnessresearch.org.uk , or call 0207 7833 1733 for further information on how to support the charity.
- The Deafness Research UK Information Service provides free information and advice based on the latest scientific evidence and informed by leading experts. The Information Service can be contacted on Freephone 0808 808 2222.
- For more information on research into deafness, tinnitus and other hearing conditions, log on to the website at www.deafnessresearch.org.uk where you can access a wide range of information. Alternatively you can e-mail Deafness Research UK at
- One in seven people in the UK – almost nine million people – suffer hearing loss.
- Deafness Research UK was founded in 1985 by Lord (Jack) and Lady Ashley of Stoke.
- In January 2008, Action for Tinnitus Research (ATR) was linked with Deafness Research UK under a uniting direction order under section 96(6) of the Charities Act 1993.
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Ref: DR-UK0235 – Ear Regeneration for Deaf Awareness Week 2010