A hope for those with hearing loss/tinnitus?

[trane_fanatic]

Some say five years...

http://www.sciencedaily.com/releases/2008/...80830005613.htm

Treatment For Hearing Loss? Scientists Grow Hair Cells Involved in Hearing

ScienceDaily (Aug. 30, 2008) — Oregon Health & Science University scientists have successfully produced functional auditory hair cells in the cochlea of the mouse inner ear. The breakthrough suggests that a new therapy may be developed in the future to successfully treat hearing loss. The results of this research was recently published by the journal Nature.

“One approach to restore auditory function is to replace defective cells with healthy new cells,” said John Brigande, Ph.D., an assistant professor of otolaryngology at the Oregon Hearing Research Center in the OHSU School of Medicine. “Our work shows that it is possible to produce functional auditory hair cells in the mammalian cochlea.”

The researchers specifically focused on the tiny hair cells located in a portion of the ear’s cochlea called the organ of Corti. It has long been understood that as these hair cells die, hearing loss occurs. Throughout a person’s life, a certain number of these cells malfunction or die naturally leading to gradual hearing loss often witnessed in aging persons. Those who are exposed to loud noises for a prolonged period or suffer from certain diseases lose more sensory hair cells than average and therefore suffer from more pronounced hearing loss.

Brigande and his colleagues were able to produce hair cells by transferring a key gene, called Atoh1, into the developing inner ears of mice. The gene was inserted along with green florescent protein (GFP) which is the molecule that makes a species of jellyfish glow. GFP is often used in research as a “marker” that a scientist can use to determine, in this case, the exact location of the Atoh1 expression. Remarkably, the gene transfer technique resulted in Atoh1 expression in the organ of Corti, where the sensory hair cells form.

Using this method, the researchers were able to trace how the inserted genetic material successfully led to hair cell production resulting in the appearance of more hair cells than are typically located in the ears of early postnatal mice. Crucially, Dr. Anthony Ricci, associate professor of otolaryngology at the Stanford University School of Medicine, demonstrated that the hair cells have electrophysiological properties consistent with wild type or endogenous hair cells, meaning that the hair cells appear to be functional. Based on these data, the scientists concluded that Atoh1 expression generates functional auditory hair cells in the inner ear of newborn mammals.

“It remains to be determined whether gene transfer into a deaf mouse will lead to the production of healthy cells that enable hearing. However, we have made an important step toward defining an approach that may lead to therapeutic intervention for hearing loss,” Brigande said.

Edited September 18, 2008 by trane_fanatic

[trane_fanatic]

http://sciencenow.sciencemag.org/cgi/conte...008/827/2?rss=1

Credit: David Woessner, John Mitchell, and John V. Brigande

Hope for Hearing Loss?

By Rachel Zelkowitz

ScienceNOW Daily News

27 August 2008

A cure for hearing loss could be closer, now that a team of scientists has produced key ear cells in mice--and for the first time verified that the cells work just like natural ones.

The inner ear turns sound waves into electrical signals inside the organ of Corti, which is lined with rows of 15,000 to 20,000 hairlike cells. The cells respond to vibrations by producing electrical impulses that travel via nerves to the brain. It's a fragile system; loud noises can damage the hair cells and age can deplete them, resulting in hearing loss. Researchers guessed that they could restore some hearing by replacing those hair cells. Previous studies isolated a protein called Atoh1, which triggers hair-cell growth. But it wasn't clear that the engineered cells would have the same mechanical and electrical properties as normal ones when produced in an animal.

To address that concern, John Brigande, a developmental neurobiologist at Oregon Health and Science University in Portland, and colleagues injected embryonic mice with DNA containing several copies of Atoh1. The researchers inserted the genes about a week before birth--after they could identify tissue that would become the inner ear and before the natural development of hair cells had begun. Four days after the mice were born, the researchers examined their hair cells.

Mice that produced the extra Atoh1 had almost twice as many hair cells as did control mice, the researchers report today in Nature. Electron microscopy revealed that the extra hair cells were divided into inner and outer hair cells, just like the normal ones, and they made the same proteins. Next, the researchers determined that the engineered cells responded to sound waves and turned them into electrical signals.

The findings show that Atoh1 replacement therapy can produce viable hair cells in animals, Brigande says. "That's exciting because it offers a strong rationale to pursue cell-replacement strategies for hearing loss."

Other auditory experts agree. Matthew Kelley, a developmental neuroscientist at the National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland, applauds the method of introducing the Atoh1 during the embryonic stage. "It's a brand-new technique. This has been one of the major challenges and roadblocks in inner ear research."

Yehoash Raphael, an auditory neuroscientist at the University of Michigan, Ann Arbor, says the findings provide a new delivery model for researchers trying to use developmental genes to restore lost hearing. But before researchers can develop a treatment for humans, they have to answer questions such as how many copies of Atoh1 are necessary to stimulate hair-cell regrowth and what is the best way to deliver the gene to a human organ of Corti.

[kenny weir]

Huh? What was that again?

Oh - man, that's great news.

The faster the better.

Tinnitus Kenny

[Free For All]

I have a moderate case of tinnitus from years of playing in big bands (sitting in front of trumpets and next to drummers ). I really only notice it at night when I'm trying to go to sleep (would someone please answer the friggin' phone??). I sleep with some kind of ambient noise (usually a fan) and that takes care of it.

[Jazzmoose]

I have a moderate case of tinnitus from years of playing in big bands (sitting in front of trumpets and next to drummers ). I really only notice it at night when I'm trying to go to sleep (would someone please answer the friggin' phone??). I sleep with some kind of ambient noise (usually a fan) and that takes care of it.

Same here, although mine came from plunking my head between two speakers and blasting Meddle at a ridiculous volume. Gotta have that fan going!

Damn, wouldn't it be great if this actually pans out? On the other hand, if we all had the hearing we used to have, we may have to revisit that "are you an audiophile" thread...

[Jim Alfredson]

It would indeed be nice. I need a fan as well.

[seeline]

I've got a mild case of tinnitus, probably brought on as a side effect of a drug that I was given several years ago, during a nasty ear/sinus infection. The only time I'm really aware of it is in the winter, when the windows are closed... so far, no need for fans.

But it sure would be nice to have it be gone for good.