Scientists have been trying to regenerate hair cells — sensory cells in the inner ear named for the hairlike bundles jutting from their tops — out of surrounding non-sensory cells as a way to make up for hair cell loss in ears damaged by noise, some medicines, and other sources. (Unlike other vertebrates, mammals aren’t able to grow new hair cells on their own once the cells are dead or damaged.) But new NIDCD-funded research from Creighton University, Nebraska, and the Chinese PLA General Hospital, Beijing, says that hair cells damaged by noise may have more life in them than we once thought. We may be able to regenerate new hair bundles — called stereocilia — from the original hair cells. The researchers subjected guinea pigs to an impulse noise simulating gunfire, resulting in severe hearing loss. Using scanning electron microscopy, they showed extensive stereocilia damage had occurred throughout the inner ear. However, when the researchers injected math1, a key gene for the development of hair cells, into the inner ear within one week of damage, they found that the stereocilia were able to grow back. Furthermore, key measurements showed that the new stereocilia were able to convert sound vibrations into electrical signals, which is how the brain interprets sound. The researchers caution that there is a window of time when the hair cells are still viable following noise damage. If the hair cells are not rescued within that time frame, they will die. But if researchers are able to intervene early enough — within 10 days — the hair cells can possibly be saved. The researchers plan to conduct tissue culture studies to confirm whether these findings are supported at the cellular level.
The talk "Regeneration of Stereocilia of Cochlear Hair Cells by Math1 Gene Therapy" (#484) takes place Sunday, Feb. 7, at 5:00 p.m. PT in the Disneyland South Ballroom.
http://www.nih.gov/news/health/feb2010/nidcd-04.htm
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