Sensory Hair Cells Regenerated in Mammal Ear

[Waldo Bracamontes]

Hearing loss is a significant public health problem affecting close to 50 million people in the United States alone. Sensorineural hearing loss is the most common form and is caused by the loss of sensory hair cells in the cochlea. Hair cell loss results from a variety of factors including noise exposure, aging, toxins, infections, and certain antibiotics and anti-cancer drugs. Although hearing aids and cochlear implants can ameliorate the symptoms somewhat, there are no known treatments to restore hearing, because auditory hair cells in mammals, unlike those in birds or fish, do not regenerate once lost. Auditory hair cell replacement holds great promise as a treatment that could restore hearing after loss of hair cells.

In the Jan. 10 issue of Neuron, Massachusetts Eye and Ear and Harvard Medical School researchers demonstrate for the first time that hair cells can be regenerated in an adult mammalian ear by using a drug to stimulate resident cells to become new hair cells, resulting in partial recovery of hearing in mouse ears damaged by noise trauma. This finding holds great potential for future therapeutic application that may someday reverse deafness in humans.

"Hair cells are the primary receptor cells for sound and are responsible for the sense of hearing," explains senior author, Dr. Albert Edge, of Harvard Medical School and Mass. Eye and Ear. "We show that hair cells can be generated in a damaged cochlea and that hair cell replacement leads to an improvement in hearing."

In the experiment, the researchers applied a drug to the cochlea of deaf mice. The drug had been selected for its ability to generate hair cells when added to stem cells isolated from the ear. It acted by inhibiting an enzyme called gamma-secretase that activates a number of cellular pathways. The drug applied to the cochlea inhibited a signal generated by a protein called Notch on the surface of cells that surround hair cells. These supporting cells turned into new hair cells upon treatment with the drug. Replacing hair cells improved hearing in the mice, and the improved hearing could be traced to the areas in which supporting cells had become new hair cells. "The missing hair cells had been replaced by new hair cells after the drug treatment, and analysis of their location allowed us to correlate the improvement in hearing to the areas where the hair cells were replaced," Dr. Edge said.

This is the first demonstration of hair cell regeneration in an adult mammal. "We're excited about these results because they are a step forward in the biology of regeneration and prove that mammalian hair cells have the capacity to regenerate," Dr. Edge said. "With more research, we think that regeneration of hair cells opens the door to potential therapeutic applications in deafness."


Read more at: http://medicalxpress.com/news/2013-01-sensory-hair-cells-regenerated-mammal.html#jCp

 

[DezDog]

Discussion of said article on reddit:

http://www.reddit.com/r/science/com...regenerated_hearing_restored/?sort=confidence

 

[Waldo Bracamontes]

What do you guys think about this Article? Yeah, DD i saw that last night.

 

[Louise]

I feel well miffed that birds and fish can regenerate theirs but we cant?

 

[Waldo Bracamontes]

Louise, I think the fact that they have been around for Billions of Years, they have evolved in a way were the body can make those changes accordingly.

 

[mock turtle]

and generally birds hearing spectrum is lower than humans and other mammals...that is many bird species can not hear above 6 or 7 kHz

 

[mock turtle]

thanks waldo bracamontes

btw
there is a video of dr albert edge discussing the research... i found the url at the report you linked to

heres the direct route
http://www.cell.com/neuron/retrieve/pii/S0896627312009531

 

[Louise]

Looks good. I wish this stuff wasnt so far away

 

[mock turtle]

Louise, yeah me too

there was a report on NPR about dr edge's research and it was said by either him or another researcher that implementing this treatment was 10 or 20 years away

what nonsense..there are people who have lost sight and hearing and are considering ending it all... who would gladly volunteer, like astronauts going into space, to be the pioneers trying desperately to push forward this horizon

im not young, in 10 or 20 years i could be pushin up daisies

but im glad the younger people here, who are afflicted, clearly have several possible (probable) cures on the horizon

hang on you youngsters!

best wishes
mock turtle

 

[Louise]

Yeah, there is real hope for the young 'uns. Although when you're that young 40 seems ancient and you dont think you're ever going to reach it so it possibly cold comfort to them

I'll be 70 by then and no-one is gonna care about my ears being regenerated

I would volunteer I think.

If only the big drug companies etc had become interested 50 years ago instead of 10.

 

[Waldo Bracamontes]

MT, Yeah the video was very interesting. Really, brakes down what they are working on. Thanks MT.

 

[Louise]

Sorry, but I'm still miffed off with the birds.
So, of a Friday night a bird can don its tight jeans and leather jacket, stroll down the local, sink a few, listen to a rousing rendition of 'Paranoid' with its head next to a speaker and the next morning be completely unscathed because its regrown back its IHCs and we cant? Not fair!

 

[DezDog]

Yes, but can they walk without nodding their heads. No, they can't. Humans 1, Avians 0.

 

[Waldo Bracamontes]

-The question is why can't humans grow them back? mmmm...

 

[mock turtle]

humans thus far hav not been able to regrow stereo cillia back, naturally, because we possess a special anti tumor protein, called retinoblatoma (Rb1 gene) which not only suppresses cancers but unfortunately also suppresses the regeneration of stereo cilia

there is current research about this and other tinnitus and hearing treatments going on at the university of washington bloedel research center

http://depts.washington.edu/hearing/

 

[Waldo Bracamontes]

Thank you MT, i will read that page. Interesting stuff.

 

[mock turtle]

Waldo.., the bleodel web site has great information...but...., .this article is more to the point, hope i didnt waiste your time

"

In the study, the research team surveyed all the genes that are active during the embryonic development of the inner ear. The researchers discovered that a protein made by the retinoblastoma, or Rb1, gene halted the growth of hair cells. In effect, they found that the Rb1 protein was a molecular switch that turned off hair cell proliferation.​

They then studied a mouse developed by Philip Hinds of the Tufts-New England Medical Center that did not express Rb1 protein in the inner ear. Mice lacking this gene tended to run in circles, suggesting an abnormality in the balance system. Researchers found that the animals had more hair cells in their inner ears than did mice with normal Rb1 genes and that the surplus cells were functional, capable of relaying electrical signals to the brain.​

Chen said he cultured hair cells that lacked the Rb1 gene and found that they did divide, growing new hair cells, and that the process stopped when the Rb1 protein was added.​

Although the studies were only in mice, Chen said the ear structure of the mouse is very similar to that of humans.​

The researchers now are screening chemicals that would neutralize the Rb1 protein and, thus, cause hair cells to grow."​

​

you can read the entire article at​

http://usatoday30.usatoday.com/news/health/2005-01-13-gene-deafness_x.htm​

​

best wishes​

mt​

​

 

[Waldo Bracamontes]

Thank you MT, interesting Article. I like it, brings plenty of hope!

Have a good one, Mt...

Waldo.

 

[nookie]

A drug that restores hearing in deaf mice

George Dvorsky

Advances in regenerative medicine are coming in fast and furious these days, and a remarkable new breakthrough can be added to the list. Scientists at Massachusetts Eye and Ear and Harvard Medical School have restored partial hearing in mice suffering from sensorineural hearing loss — a condition that happens after prolonged exposure to noise. Given the rise of an aging population — not to mention a preponderance of people who blast their ears with portable MP3 players — it's an important bit of scientific insight that could someday help millions of people get their hearing back.
To learn more about this important breakthrough, we contacted lead researcher Dr. Albert Edge, whose study appears in the January 10 issue of Neuron.

​

Edge agreed that sensorineural hearing loss is a growing concern.
"The National Institute of Deafness and Communications Disorders of the NIH estimates that approximately 15 percent of Americans between the ages of 20 and 69 have hearing loss due to exposure to loud sounds or noise at work or in leisure activities," he told io9. "So this is a very serious problem with little that can be done to treat it."
No doubt, it's a problem that currently affects 250 million people worldwide.
Edge says that hearing aids can help, but his team is hoping to develop a treatment that goes all the way — one that can actually replace the lost cells.


An irreversible problem?
Indeed, it's the loss of sensory hair cells in the cochlea that causes a gradual decline in hearing quality — a condition that comes about after excessive and long-term exposure to noise, as well as aging, toxins, infections, and even some antibiotics and anti-cancer drugs. Without these hairs, the hearing pathway is blocked, and signals cannot be received in the auditory cortex of the brain.
Unlike birds and fish, mammals cannot regenerate auditory hair cells once they start to degrade — a condition that makes it harder to hear over time, and what also causes a persistent ringing in the ears (what's known as tinnitus). It was this apparent problem of irreversibility that Edge and his team confronted.
"There aren't currently any treatments and few experimental approaches," he told us. It was for this reason that they tried something a bit more radical — a drug treatment that could target the endogenous cells left in the cochlea.


LY411575
And this is precisely what they managed to achieve.

http://img.gawkerassets.com/img/18azxi43nkpdvpng/original.png​

​

​

​

Specifically, the researchers demonstrated for the first time that hair cells can in fact be regenerated in an adult mammalian ear by using a drug, codenamed LY411575, to coax nearby ear cells to transform into new hair cells. It was a technique that ultimately resulted in the partial recovery of hearing in mice who experienced ear damage caused by noise trauma (yes, the researchers deafened the mice with loud noise).

For the experiment, Edge administered the drug directly into the cochlear region of the deaf mice — a highly specialized drug selected for its ability to spawn hair cells when added to stem cells taken from the ear.
Then, after the inhibition of a protein called Notch (which is on the surface of cells that surround hair cells), the resident cells were converted into new, functional hair cells. Notch has previously been shown to prevent stem cells in the cochlea from transforming — a problem that the researchers were able to overcome.
In fact, the new hair cells created a measurable improvement in the hearing of the mice after just three months — changes that could be traced to the presence of newly generated hair cells (the scientists used a green fluorescent protein to isolate the new hair cells). And the improvements were measured over a wide range of frequencies.
"This is a new way of inducing hair cell replacement by driving remaining cochlear cells to become new hair cells," said Edge.
Moving forward, Edge told io9 that he hopes to test additional drugs and look at other forms of hearing loss. Moreover, because the therapy improved hearing in mammals, the regeneration of hair cells could introduce opportunities into potential therapeutic applications in treating sensorimotor deafness in humans.
Link to the study can be found here: http://www.cell.com/neuron/abstract/S0896-6273(12)00953-1

 

[exodus]

hi it was already discussed here
https://www.tinnitustalk.com/threads/sensory-hair-cells-regenerated-in-mammal-ear.872/

 

[Markku]

hi it was already discussed here
https://www.tinnitustalk.com/threads/sensory-hair-cells-regenerated-in-mammal-ear.872/

Merged. Thank you for noticing and reporting!

Markku

 

[charles walker]

Has any of you thought to just purchase some LY411575 and put it around the ear area, let it absorb directly into the skin, maybe add a dash of DMSO to aid that & do your own experimenting? LY411575 is apparently available on the web at several places.

 

[RaZaH]

Why do mice get all the good stuff ?

 

[rainman]

If there is going to be a group buy in some time in the future, then i'll be totally in!

 

[tom68]

Tempting though it is apparently it is toxic and those links mention something about the protein that stops hair cell regrowth also being a tumour suppressant I think I may wait until we run our own Tinnitus Talk stage 2 trials!!

 

[tom68]

Why do mice get all the good stuff ?

I know, I thinking of getting me one of these http://www.halloweencostumes.com/plus-size-mouse-costume.html. Then all I gotta do is break into that lab....

 

[RaZaH]

I will go with , I can just picture it in the papers when we get caught .

 

[katriina]

I know, I thinking of getting me one of these http://www.halloweencostumes.com/plus-size-mouse-costume.html. Then all I gotta do is break into that lab....

This could be our new way to raise tinnitus awareness "We are just so desperate!" lol

 

[DutchGuy]

Just read about it on a Dutch T and H site.

Here you can buy the stuff? :

http://www.apexbt.com/ly-411575.html?gclid=CIbnpvmbmcICFWf3wgodeikAmw

http://www.selleckchem.com/products/ly-411575.html?gclid=COCzx4GcmcICFUWWtAod-GIA5g

 

[JohnK]

One year later, no progress. What on earth happens to these discoveries??