Gerbils Regain Hearing Thanks to Stem Cell Therapy

thanks erik

but hey the researches declaration that protocols indicate a 15 year time horizon...huh

ill bet there are some people in such dire straights that they would volunteer today, to" boldly go where no one has gone before"

best wishes
mt

 

Human embryonic stem cells restore gerbil hearing

Nature
Virginia Gewin
12 September 2012

More than 275 million people have moderate-to-profound hearing loss, and many of those cases are caused by a breach in the connection between the inner ear and the brain.

Researchers have now shown how to repair a key component of that connection — the auditory nerve — by using human embryonic stem cells to restore hearing in gerbils. "We have the proof of concept that we can use human embryonic stem cells to repair the damaged ear," says lead author Marcelo Rivolta, a stem-cell biologist at the University of Sheffield, UK, whose research appears in Nature today. "More work needs to be done, but now we know it's possible."

Stem cells have been differentiated into auditory nerve cells before, but this is the first time that transplanted cells have successfully restored hearing in animals. Some in the field say that it is a pivotal step that will undoubtedly spur more research. “Research has been stymied by reviewers wanting evidence that stem cells can connect the inner ear to the central nervous system,” says Richard Altschuler, a developmental biologist at the Kresge Hearing Research Institute at the University of Michigan in Ann Arbor.

Rivolta has spent the past decade developing ways to differentiate human embryonic stem cells into the two cell types that are essential for hearing: auditory neurons, and the inner-ear hair cells that translate sound into electrical signals.

He treated human embryonic stem cells with two types of fibroblast growth factor (FGF) — FGF3 and FGF10 — to produce two, visually distinct, groups of primordial sensory cell. Those that had characteristics similar to hair cells were dubbed otic epithelial progenitors (OEPs), and those that looked more like neurons were dubbed otic neural progenitors (ONPs).

His team then transplanted ONPs into the ears of gerbils that had been treated with ouabain, a chemical that damages auditory nerves, but not hair cells. Ten weeks after the procedure, some of the transplanted cells had grown projections that formed connections to the brain stem. Subsequent testing showed that many of the animals could hear much fainter sounds after transplantation, with an overall improvement in hearing of 46%.

Rivolta’s findings — along with a study published in July showing that gene therapy can restore hearing in deaf-born mice — reinforce a spate of studies demonstrating that stem cells and gene therapy can restore sensory functions, including smell (see 'Gene therapy restores sense of smell to mice') and vision (see 'Regenerative medicine repairs mice from top to toe').

The advances are exciting, says John Brigande, a developmental biologist at Oregon Health & Science University in Portland who has a progressive form of hearing loss and is exploring stem-cell-based approaches to restore auditory function. He notes, however, that because the “exquisite architecture” of the inner ear can be damaged in many different ways, ”there won’t be one cure for hearing loss, there will be a variety of interventions tailored to unique conditions”.

The number of people who might benefit from a stem-cell-driven increase in auditory neurons remains unclear, but stem cells could broaden the reach of existing therapies. “Because functioning auditory neurons are necessary for cochlear implants to work, stem cells open a candidate pool that cannot yet be helped,” says Altschuler.

The first treatments for hearing could take at least 15 years to develop, says Stefan Heller, a stem-cell researcher at Stanford University in California who is working on other ways to differentiate stem cells into hair cells and support cells. “The next goals of any protocol are to gain higher levels of efficiency and reproducibility, determine protocol safety and confirm that transplantation leads to prolonged recovery,” says Heller. “Then we can think about patients.”

source: http://www.nature.com/news/human-embryonic-stem-cells-restore-gerbil-hearing-1.11402

 

doc....gimmie them stem cells.....im not a turtle...im a gerbil

 

I want to illustrate the significance of this study. Kuwaja and Schaettes recent paper in the last 5 years or so illustrated that tinnitus can occur with a normal audiogram. Kuwaja demonstrated loss of synaptic ribbon (which represents synapse between cochlear nerve and inner hair cells) with eventual degeneration of cochlear nerve but intact inner hair cell. Schaette demonstrated the same thing, but through ABR measurements that reflect cochlear damage.

The importance of this? Those with tinnitus and 'normal' audiogram (myself included) but with putative cochlear nerve damage/degeneration will benefit. The study shows that not only do the stem cells differentiate into a cochlear nerve neuron, but that it ALSO travels to the brain and makes the appropriate connections to restore hearing.

The caveat here is, is the plasticity changes occurring in tinnitus able to be reversed with re-afferentation? A similar study by Schaette with induced tinnitus percept through long-term ear-plug wearing demonstrated that tinnitus disappeared once participants removed the ear plug. This seems to suggest that at least in the short-term, tinnitus is reversible once we restore input. Whether this also holds true for long-term tinnitus is another question that has yet to be studied.

Conclusion: astoundingly great news for restoring hearing, super great news also for tinnitus though with some grain of salt

 

I have been always wondering, why is the theory about permanent plasticity changes within the brain so popular? There is not much evidence about it, is there? Even if it's true, I see no reason why should they be irreversible.

If I understand it correctly, the theory is that damaged hair cells put the brain in an "alert mode" and some changes within the nerves occur to compensate for the hearing loss, causing tinnitus. Difficult to express myself with my limited english vocabulary but you know what I mean.

So in theory, if stem cell injection fixes the damaged hair cells and restores hearing, wouldn't the nerves/brain just change back again to stop compensating if it is no longer needed? I believe we might soon find out...

 

Fish, no limits to your English vocab detected here, and very well explained.

I think there is a lot of rehabilitation for brain-damaged patients that relies on plasticity. Permanent plasticity therefore sounds like an oxymoron. (Like "rigid rubber" or "non-soakable sponge"). Anyway - what do I know - I'm a software developer.

 

why 15 years..?? when technolgy is going faster en faster...
we all have hearingloss...aging is losing...we need more investing people

 

The researcher talked about in this article is actually conducting a study trying to find the perfect way to deliver stem cell to the cochlea. I think it involves some kind of gel. There is a thread somewhere talking about it I think it was in late August.

 

That's the problem with the transition between experimental science and medicine, you can't really come up with an experimental solution, try it on a few animals then jump on the human subject, everything needs to be accepted by medicine institution, you can maybe volunteer to be in the first trials on humans but that's far from the being the perfect technique at the time. Some time, treatments are working but are not accepted either ethically or just methodologically and doctors won't use them to avoid any bad reputation, but that doesn't seem to be the problem here, we can only wait to see it on our local hospital.
Take care mate, we're not that far from relief.

 

Blimy ..Richard Gere will be worried

 

Sometimes I wish I were a mouse or in this case a gerbil

 

Well, they have to destroy your hearing before they attempt to cure it.

 

They have now developed ways to get the stem cells into the inner ear. That was the biggest challenge according to the article back in 2012. Those same stem cells were from humans and would probably work better on humans than gerbils. Someone needs to open up a stem cell clinic and just offer this service. I'm pretty sure its that easy.