Researchers have tracked a cell-to-cell signaling pathway that designates the future location of the ear's sensory organs in embryonic mice. The scientists succeeded in activating this signal more widely across the embryonic tissue that becomes the inner ear. Patches of sensory structures began growing in spots where they don't normally appear.
The structures contained tufted cells, called hair cells, which respond to sound waves and other sensations, and additional nerve cells that amplify or code sounds for the brain to interpret.
The results suggest an avenue for further investigation in restoring hearing loss from nerve damage.
The findings are reported this week in the early online edition of Proceedings of the National Academy of Sciences by researchers Byron H. Hartman, Thomas Reh, and Olivia Bermingham- McDonogh of the Department of Biological Structure at the University of Washington (UW) in Seattle. All three are members of the UW Institute for Stem Cells and Regenerative Medicine. The senior author, Bermingham-McDonogh, is also an affiliate of the UW Virginia Merrill Bloedel Hearing Research Center.
"As the population ages," said Bermingham-McDonogh, "there's a great interest in discovering how to regenerate the inner ear sensory cells that we need for our hearing and balance. Both of these falter as we get older -- we get hard of hearing and unsteady on our feet -- due to accumulated destruction of the sensory cells in the inner ear."
The goal of their research is to develop ways to restore inner ear sensory hair cells in people who have lost them due to age, excessive noise or other toxic damage. The hair cells do not spontaneously recover after they are lost, and adult stem cells have not been found in the mammalian inner ear. In order to devise a way to restart hair cell formation in the adult ear, Bermingham-McDonogh's group is studying how hair cells are made in the first place during e
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University of Washington