Disease Fact Sheets
All Diseases	Deafness

Stem cells can be coaxed to form the hair-like structures in the ear that transmit sound waves to the brain. CIRM funds several research projects aiming to develop ways of treating forms of deafness with these cells.

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Stem Cell Basics Primer | Stem Cell Videos | What We Fund

Find clinical trials:
CIRM does not track stem cell clinical trials. If you or a family member is interested in participating in a clinical trial, please see the national trial database to find a trial near you: clinicaltrials.gov

Description

In 2009, researchers from Sheffield University in the United Kingdom took neuronal stem cells and converted them into cells that behave like sensory hair cells that detect noise in the human inner ear. Their discovery raised the hope that stem cells could ultimately help those who have lost ear hair cells through noise damage and even assist some people born with inherited hearing problems. The Sheffield researchers are currently seeing if these cells can restore hearing.

Then, in 2011 Australian scientists showed - for the first time in mice - that nasal stem cells injected into the inner ear have the potential to reverse or restore hearing during early onset hearing loss.

Hearing loss occurs when hearing cells in the cochlea lose their function. Frequently inherited, and usually starting during infancy and early childhood, the condition can slow a child's development and lead to speech and language problems. The mice used in the study have a very similar form of childhood deafness to their human counterparts - except, of course, that mouse years are shorter. So a mouse will tend to lose their hearing within 3 months, where a person might take 8 years.

Researchers from Sydney's Garvan Institute of Medical Research found that stem cells appear to release chemical substances that help preserve the function of cochlear hearing cells, without the stem cells becoming part of the tissue of the inner ear. Adult human nasal stem cells were used in the procedure, because they are plentiful and easy to obtain. The same group of scientists has shown in previous research that stem cells can also be used to improve hearing in noise-induced hearing loss - a condition that affects both young and older people.

The California Institute for Regenerative Medicine (CIRM) is currently funding two research teams looking into the use of stem cells in the treatment of deafness.

Dr Ebenezer Yamoah, from the University of California Davis is working on a model whereby it is possible to stimulate hair cell regeneration in the human inner ear and to also enable the functional innervations of hair cells by neurons.

The group’s research has already created new hair cells and they are currently testing whether factors regulate hair cell differentiation and whether specific human embryonic stem cell-types have the potential to differentiate into hair cells and their innervating neurons.

CIRM is also funding research by Stanford University’s Stefan Heller and his team. The scientists are looking at the potential of at least five human embryonic stem cell lines to develop into hair cells. The ultimate goal of this research is to provide an abundant source of human inner ear progenitor cells that can be tapped in the future to routinely create human hair cells for in vitro and in vivo experiments and for clinical studies aimed to repair damaged ears.

CIRM Grants Targeting Deafness

CIRM Deafness Videos

News and Information

• CIRMResearch Blog entries on deafness research
• Stem Cells Explored As Hearing Loss Treatment (Stanford University)
• UC Davis researchers coax brain cells to mimic inner ear sensory cells (UC Davis)

Resources

• NIH Hearing Loss Information
• Find a clinical trial near you: NIH Clinical Trials database
• Deafness Research Foundation
• National Association of the Deaf
• Hearing Loss Association of America