Marcelo Rivolta has a reason to be excited. The research biologist and his colleagues at University of Sheffield in the UK have had a major breakthrough in research which could make life a lot easier for some 275 million people in the world.

Rivolta, also the lead author of the paper that appears in Nature, wrote, "We have the proof of concept that we can use human embryonic stem cells to repair the damaged ear." The biologists managed to use human embryonic cells to repair damaged hearing in a gerbil, and are eager to perform more studies to ensure it can be done on a consistent basis.

Nerve deafness is the most common cause of hearing loss, when the tiny hair follicles in the inner ear become damaged or die. Symptoms of this type of hearing loss might include a persistent ringing in the ears, inability to hear high-pitch sounds like whistles, and an inability to follow conversations. Often people with sensorineural hearing loss (nerve deafness) make mistakes in understanding words.

For example, say someone tells you, "I think you'll get an 'A' on your test," but you hear it as, "I think you're getting hair on your chest." People with this type of hearing loss experience these types of misunderstandings often, which frustrates social interactions, and can isolate the person from friends, family, and coworkers because of this.

Of course, not all people with hearing loss will embrace this development. The cochlear implant is already a contentious and controversial device that gives those with nerve deafness mechanical hearing that bypasses the ears and sends sound directly into the brain. Some in the deaf community feel as though curing deafness is a form of genocide. This is an extreme opinion, however, and not everyone in the deaf community feels this way.

Others object to the use of human embryonic cells because it destroys a living embryo despite the fact that it is not a fully formed human being. The objections are mostly from religious folks who believe that life starts at conception, and the destruction of an embryo is unacceptable to them on moral grounds.

Regardless of various opinions on the matter, the fact that a previously irreversible condition was reversed by human embryonic stem-cells is a phenomenal step forward in research science. It is heralding in a new age of medicine in which people with heart disease or lung cancer might have hope for a more healthy future.

Researchers say that the inner ear, where nerve deafness occurs, is a complex organ, and the gerbil research was only one of many ways that they can approach a solution to progressive hearing loss and even in people who were born deaf.

If you had a hearing loss due to inner ear nerve damage, would you want to be "cured" this way?

Image credit: Nissim Benvenisty, Wikimedia Commons

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Amazing! Stem Cells Restore Deaf Gerbil's Hearing!

WEDNESDAY, Sept. 12 (HealthDay News) -- Using nerve cells grown from human embryonic stem cells, researchers report that they restored hearing in deaf gerbils.

About 80 percent to 90 percent of deafness is due to problems with the cells in the inner ear, explained senior study author Marcelo Rivolta, a reader in sensory stem cell biology at the University of Sheffield, in England. In the inner ear, two types of cells are key to hearing. One type are tiny projections called hair cells, which convert sound vibrations into electrical signals, which then travel along the auditory nerve to the brain.

When hair cells are damaged, cochlear implants can help overcome that by converting sound vibrations into electrical signals, bypassing the hair cells and directing stimulating the auditory nerve, experts explained. But when the cause of deafness is damage to the neurons that make up the auditory nerve, much less can be done about it, Rivolta said.

"We have concentrated on trying to fix the problem at the neuronal level. The cochlear implant is a device that functionally replaces the hair cell -- it takes sound and transforms it into an electrical signal," Rivolta said. "But for the cochlear implant to work, you have to have a good connection to the brain."

In the study, which is published online in the Sept. 12 issue of Nature, researchers coaxed human embryonic stem cells -- which have the potential to grow into any type of cell in the body -- into differentiating into otic (ear) progenitor cells. They did this by placing the stem cells into a test tube that contained certain molecules known to be present during fetal development when the ear forms.

Progenitors are immature cells that haven't fully differentiated into their specific role, but have certain characteristics that have started them down that path. Researchers then further coaxed the progenitors into becoming hair cells or auditory neurons.

"We have a system in vitro [in a test tube] that we can use to produce these important cell types, a little factory of hair cells and neurons whenever we need them," Rivolta said.

Researchers then transplanted the progenitor cells into about a dozen gerbils that had auditory nerve damage. Ten weeks after transplantation, brain wave measurements showed the gerbils could hear again.

"What we have seen is the progenitors engraft, survive and connect to the other cells that are there, and more important, they produce a functional recovery," Rivolta said.

Though exciting, much needs to be learned before the technique could be used in humans, Rivolta said.

Link:
Human Stem Cells Restore Hearing to Deaf Gerbils in Study

(CBS News) Scientists have restored hearing in gerbils using a stem cell therapy that may hold promise for deaf humans.

Using human embryonic stem cells, researchers at the University of Sheffield were able to implant immature nerve cells into gerbils, which then regenerated and were able to improve hearing ability in the animals. The study was published on Sept. 12 in Nature.

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According to a Nature News article on the study, more than 275 million people have moderate-to-profound hearing loss, many of whom have it caused by a disruption in communication between the inner ear and brain. Senior study author Dr. Marcelo Rivolta, a stem cell researcher at the University of Sheffield told HealthDay that about 80 to 90 percent of deafness is due to problems with cells in the inner ear.

There are two types of inner ear cells. Hair cells translate vibrations into electrical signals that are transmitted via the auditory nerve to the brain. Problems with these cells are typically fixed via cochlear implant, a small device which can bypass the hair cells and directly send signals to intact auditory nerves. Neurons make up the auditory nerve, and when these are damaged, doctors have little to no treatment options available.

It's important to note that the type of deafness that the gerbils had affected only neurons, making it very rare. The Associated Press points out that type of deafness only affects between less than 1 percent to 15 percent of patients. Furthermore, the treatment won't work in all the patients with that disorder.

But, because so many disorders have to do with inner ear cell problems, the research is promising and may have future human applications.

Researchers in the study took embryonic stem cells, which can develop into any other kind of cell in the body, and grew them into a test tube that had molecules that are available when the fetus develops ears, known as fibroblast growth factors (FGFs). Some stem cells developed characteristics similar to hair cells and others turned into cells that looked like neurons.

Then the neuron-like cells, which were called otic neural progenitors (ONPs), were transplanted into the ears of gerbils that had been given ouabain, a chemical that damages the neurons in the auditory nerves but not the hair cells.

Ten weeks later, the cells had grown and some connected to the brain stem. The gerbils on average had a 46 percent overall improvement in hearing, with many of the animals registering brain activity at much fainter sounds after the transplant.

Originally posted here:
Gerbils regain hearing thanks to stem cell therapy

12 September 2012 Last updated at 13:00 ET By James Gallagher Health and science reporter, BBC News

UK researchers say they have taken a huge step forward in treating deafness after stem cells were used to restore hearing in animals for the first time.

Hearing partially improved when nerves in the ear, which pass sounds into the brain, were rebuilt in gerbils - a UK study in the journal Nature reports.

Getting the same improvement in people would be a shift from being unable to hear traffic to hearing a conversation.

However, treating humans is still a distant prospect.

If you want to listen to the radio or have a chat with a friend your ear has to convert sound waves in the air into electrical signals which the brain will understand.

This happens deep inside the inner ear where vibrations move tiny hairs and this movement creates an electrical signal.

However, in about one in 10 people with profound hearing loss, nerve cells which should pick up the signal are damaged. It is like dropping the baton after the first leg of a relay race.

The aim of researchers at the University of Sheffield was to replace those baton-dropping nerve cells, called spiral ganglion neurons, with new ones.

While there is excitement at the prospect of using stem cells to restore nerves in the ear this exact technique will not help the vast, vast majority of people with hearing loss.

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Deaf 'hear again' with stem cells

Neurons (in yellow) derived from human embryonic stem cells have restored hearing to deaf gerbils.

Marcelo Rivolta, University of Sheffield

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 gerbils1. "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 ofthe 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%.

Rivoltas findings along with a study published in July showing that gene therapy can restore hearing in deaf-born mice2 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 wont be one cure for hearing loss, there will be a variety of interventions tailored to unique conditions.

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Human embryonic stem cells restore gerbil hearing

The demonstration in rodents could one day be combined with cochlear implants to treat more people than is currently possible.

Sound effects: Human stem-cell-derived neurons repopulate the inner ear of deaf gerbils. Human cells are labeled green, red, and yellow, where red and yellow mark mature or maturing neurons. Marcelo Rivolta, University of Sheffield

Researchers have restored hearing in deaf rodents using human embryonic stem cells, demonstrating for the first time that these cells can replace missing or damaged neurons in the auditory pathway. The authors suggest that this method could one day be used in combination with cochlear implants. Such an approach would aid more deaf patients than can currently benefit from the bionic prosthetic alone.

Cochlear implants can help patients who have lost or damaged hair cellsthe first sensory cells in the auditory pathwaybut don't work if patients have also lost the neurons that transmit the auditory information to the brain. By filling in this part of the auditory pathway, the new approach could enable doctors to use cochlear implants to treat even those patients who have lost both their hair cells and the signal-transmitting neurons.

Patients can lose these neurons if their hair cells are no longer working or are missing. "Most causes of hearing losswhether it is congenital hearing loss from some sort of genetic defect or acquired hearing loss from chronic noise exposure or powerful antibiotics or chemotherapygenerally those patients have a hair-cell-based hearing loss," says Daniel Lee, a surgeon at the Massachusetts Eye and Ear Infirmary in Boston who performs cochlear implantations. "Over time, after you lose the ability to hear due to hair-cell loss, the neurons get pruned back due to lack of activity," he says.

To address the loss of these cells, Marcelo Rivolta, a sensory-stem-cell biologist at the University of Sheffield in England, and his coauthors devised a method to turn human embryonic stem cells into ear-cell progenitors, cells that can then be transplanted into the inner ear, where they further differentiate into auditory neurons.

The researchers demonstrated that the transplanted cells could transmit sound signals into the brain. They did this by measuring the electrical activity of the neurons in response to sound. While other groups had previously shown that mouse embryonic stem cells can differentiate into these auditory neurons and grow within the inner ear after transplantation, they were unable to demonstrate a functional recovery.

The ultimate goal of stem-cell therapy is to replace both the hair cells and the neurons, says Rivolta, but the procedure is much more difficult for the hair cells. "We are still lacking a surgical technique to deliver the cells in the right place without damaging the ear. Moreover, the cells would need to graft in a perfect arrangement, at a correct angle," he says.

The stem-cell treatment could eventually be combined with cochlear implants to give more deaf patients the ability to hear. But much more work would be required to bring this idea to fruition.

While the study shows the potential of stem cells to replace auditory nerve fibers, says Stefan Heller, who studies hair-cell function and regeneration at the Stanford School of Medicine, the results will be difficult to translate to patients. "It is virtually impossible to diagnose a reduction of auditory nerve fibers in hearing-loss patients." The risk of tumor formation, an issue carried by all potential embryonic stem-cell therapies, are also carried by this treatment, he says.

Read more from the original source:
Researchers Use Human Embryonic Stem Cells to Restore Hearing

September 12, 2012 in Health

Malcolm Ritter Associated Press

Marcelo Rivolta photo

This undated photo provided by Nature shows cells in the inner ear of a deaf gerbil. The yellow ones are nerve cells derived from human embryonic cells. These cells improved the hearing of the gerbils, in an experiment that may someday help human patients. Results of the work, done in gerbils, were reported online Wednesday, Sept. 12, 2012 in the journal Nature by a team led by Dr. Marcelo Rivolta of the University of Sheffield inEngland. (Full-size photo)

NEW YORK (AP) For the first time, scientists have improved hearing in deaf animals by using human embryonic stem cells, an encouraging step for someday treating people with certain hearingdisorders.

Its a dynamite study (and) a significant leap forward, said one expert familiar with the work, Dr. Lawrence Lustig of the University of California, SanFrancisco.

The experiment involved an uncommon form of deafness, one that affects fewer than 1 percent to perhaps 15 percent of hearing-impaired people. And the treatment wouldnt necessarily apply to all cases of that disorder. Scientists hope the approach can be expanded to help with more common forms of deafness. But in any case, it will be years before human patients mightbenefit.

Results of the work, done in gerbils, were reported online Wednesday in the journal Nature by a team led by Dr. Marcelo Rivolta of the University of Sheffield inEngland.

To make the gerbils deaf in one ear, scientists killed nerve cells that transmit information from the ear to the brain. The experiment was aimed at replacing thosecells.

Read more from the original source:
Human stem cells restore hearing in gerbil study - Wed, 12 Sep 2012 PST

NEW YORK

For the first time, scientists have improved hearing in deaf animals by using human embryonic stem cells, an encouraging step for someday treating people with certain hearing disorders.

"It's a dynamite study (and) a significant leap forward," said one expert familiar with the work, Dr. Lawrence Lustig of the University of California, San Francisco.

The experiment involved an uncommon form of deafness, one that affects fewer than 1 percent to perhaps 15 percent of hearing-impaired people. And the treatment wouldn't necessarily apply to all cases of that disorder. Scientists hope the approach can be expanded to help with more common forms of deafness. But in any case, it will be years before human patients might benefit.

Results of the work, done in gerbils, were reported online Wednesday in the journal Nature by a team led by Dr. Marcelo Rivolta of the University of Sheffield in England.

To make the gerbils deaf in one ear, scientists killed nerve cells that transmit information from the ear to the brain. The experiment was aimed at replacing those cells.

Human embryonic stem cells can be manipulated to produce any type of cell. Using them is controversial because they are initially obtained by destroying embryos. Once recovered, stem cells can be grown and maintained in a lab and the experiment used cells from lab cultures.

The stem cells were used to make immature nerve cells. Those were then transplanted into the deaf ears of 18 gerbils.

Ten weeks later, the rodents' hearing ability had improved by an average of 46 percent, with recovery ranging from modest to almost complete, the researchers reported.

And how did they know the gerbils could hear in their deafened ears? They measured hearing ability by recording the response of the brain stem to sound.

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Human stem cells restore hearing in gerbil study