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Researchers create hair cells - cure for deafness on the way?

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May 18, 2010

Hair cells like these have been successfully recreated in a petri dish (Photo: CC)

Hair cells like these have been successfully recreated in a petri dish (Photo: CC)

It’s become an accepted fact of life that people tend to lose much of their hearing as they get old. This is because our hair cells, the cells in our ears which allow us to hear, cannot regenerate - we’re born with 30,000 per ear, but once they die off or get damaged, they’re gone for good. Stefan Heller, a professor of otolaryngology (ear, nose and throat stuff) at Stanford University, wants to change that. To that end, he recently succeeded in creating mouse hair cells in a petri dish. Could an end to deafness be far behind?

Heller and his team used embryonic stem cells from mice, along with mouse fibroblasts (cells found within fibrous connective tissue) reprogrammed to act like stem cells. After ten years of lab work, they were able to engineer these cells into something that looked and performed just like hair cells. “We knew it was really working when we saw them in the electron microscope,” Heller said. “They really looked like they were more or less taken out of the ear.”

The team mimicked the steps involved in the formation of a mouse’s ear in utero. They started by turning the cells into the type that form a mouse embryo’s ectoderm, or outer layer of cells. By manipulating growth factors, they then proceeded to transform them into ear cells. Finally, they altered the “chemical soup” in the petri dish, causing the cells to cluster like hair cells.

At this point the cells also developed stereocilia, which are tiny clumps of hair-like projections found on hair cells. Stereocilia bend when subjected to vibrations, converting those vibrations into electrochemical signals that the brain interprets as sound. The Stanford researchers used a probe to stimulate the synthesized stereocilia, and found that they did indeed produce an electrochemical current.

Heller is working towards producing human hair cells for transplantation, but says the engineered cells could also be used for testing possible deafness-curing medications. “We could now test thousands of drugs in a culture dish,” he explained. “It is impossible to achieve such a scale in animals. Within a decade or so we could reap the benefits of this type of screening.”

Heller’s research was recently published in the journal Cell.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
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5 Comments

Interesting. But it begs one question: Whats wrong with all the other hair on our heads? Maybe that hair can do more than just keep our scalps warm... :)

jeffbloggs
18th May, 2010 @ 09:40 pm PDT

I've been waiting for this ever since Stem Cell research came about. I KNEW this would work! I'd like to know how they plan to repair/replace the cochlea itself- it is cartillage, and turns to bone after a period of time without use. Mine are, and I really believe that for my deafness, the hairs and cochlea are all I need. I have already had a cochlear implant, it isn't a good fit for me. After 33 years of silence, I want either all of it, or nothing. I'll really look forward to this! Sign me up!

Facebook User
19th May, 2010 @ 09:57 am PDT

Wonder if this will work for those people with difficulty growing hair on their heads as well?

Ezra
19th May, 2010 @ 03:34 pm PDT

Your facts are a little off facebook user, the cochlea is not cartilage, it has two parts, a bony part (part of the temporal bone and one of the hardest bones in the body) and membranous interior (made up of a number of elements including collagen and many other proteins). The Organ of Corti, where the hair cells reside does not turn to bone without use, but depending on your development may not have fully matured. People born with normal functioning cochlea's that acquire damage (noise, age, ototoxic drugs) lose these hair cells, which are then replaced by scar like tissue from the supporting cells. Even if they can regenerate hair cells and the stereocilia, they will require appropriate connections to be functional. Outer hair cells have motility, they move up and down and provide gain to the system, if you regenerate the cell but not motility it will not be of much use. The Inner hair cell is the part of the system that stimulates the auditory nerve to send the message to the brain, if the inner hair cell is not connected (able to release it's chemical signal to the nerve fibers to generate an action potential) it will be of little help. That it can translate a current is somewhat meaningless. If you don't have a fully developed cochlea at all, the ability to regenerate or replace is even more difficult. When this research and eventual translation will be applicable to humans is at least 25-50 years off, maybe more. It would take at least 10-20 more years of research in numerous in vivo (live not in a plate) animal models before if could be approved by the FDA for human trials.

No Ezra hair on your head is not the same thing as cochlear "hair cells" which are sensory cells that happen to look a little like hair.

Chris S
20th May, 2010 @ 09:12 am PDT

i wonder if they could somehow mutate our hair cells so we could have 'superhearing'

Facebook User
2nd June, 2010 @ 08:09 pm PDT
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