by Ryan Hartwig
When you lose your hearing it is because your hair cells die within the inner ear. Unfortunately, these hair cells don’t regrow.
To remedy the effects of hearing loss, you buy hearing aids or cochlear implants.
However, hearing aids and cochlear implants basically increase the amplification inside the inner ear, without trying to replace the lost hair cells.
Gene Therapy and Stem Cell Injection
New research is exploring the possibility of regrowing your hair cells through gene therapy and stem cell injection.
A stem cell is a cell from one part of your body that can transform into another cell, with a different purpose. Neural stem cells are especially good at replacing lost hair cells.
A gene called atoh1 is necessary for hair cell formation. By inserting this gene into deaf guinea pigs, the amount of hair cells increased.
Disadvantages of Hearing Aids & Cochlear Implants
Current hearing devices increase volume, but they don’t necessarily increase speech discrimination. Although a hearing impaired individual may hear you, he may not understand you.
Speech intelligibility is the main drawback for current auditory therapies.
Through the use of biotechnologies such as gene therapy and stem cell injection, speech intelligibility may become a problem of the past.
Song without words (Felix Mendelssohn)
Have you ever wanted to hear a song, but not listen to the words? Perhaps someday we’ll have a car radio that not only has a volume control, but also an intelligibility control, for those sublime moments when we don’t really want to hear the lyrics.
This post was based on an article from the The ASHA Leader newsletter, titled “From High-Tech to Biotech: Using Stem Cell and Gene Therapy to Treat Hearing Loss”, by Mark A. Parker, June 7, 2011.
See the article here
Figure 4. Gene therapy causes supporting cells to adopt hair cell characteristics. Gene therapy
involves inserting a given gene into a virus that will then insert the gene into each cell with which it comes in contact. Engineered adenovirus particles that carried the atoh1 gene were injected into the cochleae of chemically deafened adult guinea pigs. Guinea pigs injected with the atoh1 gene had better ABR threshold and exhibited more hair cells than controls injected with virus particles lacking the atoh1 gene. Arrowheads in the far right panel highlight extra sterocilia bundles. Asterisk marks the site of injection into the scala media. Adapted from Macmillan Publishers Ltd: Nature Medicine (Izumikawa et al., 2005), © 2005.