Small hairs inside the ear that recognize sounds have been regenerated to reverse deafness for the first time, according to a new study in the journal Neuron.
A group of researchers from Massachusetts Eye and Ear Harvard Medical School have shown that hair cells can be regenerated by a using a drug to provoke cells that live inside the ear to become new hair cells. This brings about partial hearing recovery in mice with previously damaged ears.
This discovery holds great promise for future use in possibly reversing deafness in humans.
Senior author, Dr. Albert Edge, of Harvard Medical School and Mass. Eye and Ear explains:
"Hair cells are the primary receptor cells for sound and are responsible for the sense of hearing. We show that hair cells can be generated in a damaged cochlea and that hair cell replacement leads to an improvement in hearing."
Hearing loss is a public health issue that affects nearly 50 million people just in the U.S. The most common condition is known as sensorineural hearing loss which is created by the loss of sensory hair cells in the cochlea.
In order to hear, sound waves must be changed into electrical signals which the brain can interpret. The initial step of this activity happens inside the inner ear where vibrations move little hairs - the movement produces an electrical signal.
Hearing loss is normally caused by damage to these hairs. There are no known treatments to completely bring back hearing. However, there are hearing aids and cochlear implants that can reduce the symptoms slightly.
Hearing loss can never be reversed completely because auditory hair cells in mammals do not regenerate once they are gone, unlike those of birds or fish. The findings from this study could be a stepping stone for treatment that could bring back hearing after loss of hair cells.
During the experiment, the investigators used a drug that generates hair cells when combined with stem cells outside of the ear. They administered this drug to the cochlea of deaf mice.
The drug was aimed at cells which normally give support to individual hairs. It then changed the path of the cells by changing which genes were being used in the cells, to alter them into hair cells.
Dr. Edge explained:
"The missing hair cells had been replaced by new hair cells after the drug treatment, and analysis of their location allowed us to correlate the improvement in hearing to the areas where the hair cells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."
The results of this study demonstrate the first hair cell regeneration in an adult mammal. The researchers are excited about the outcomes and their future implications in the possible treatment of deafness in humans.
Written by Kelly Fitzgerald
Copyright: Medical News Today
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need for fast forwarding
posted by Marilyn on 16 Apr 2013 at 9:49 am
I am like others that have posted, this is something that has longtime been determined. We HOH are not any better off than when this was introduced several years ago. The need is to take it forward instead of keep repeating what has already been determined!
Around 2000, I remember, a very similar study has been published via MIT. From the standpoint of any kind of engineering project, this is catastrophic that we are still at the same point. Nearly 15 years and probably more, still we do not have anything solid. I think such kind of studies should be more competitively funded. This is not ENOUGH satisfactory.
At age 60,I have what is considered hearing loss due to ageing. Loosing any level of hearing is a huge impairment to functioning in the hearing world. Communicating with grandchildren is high on my list of concerns. Annoying others by constantly requiring repetition of statements is not a minor concern. Let's hope this research is given top priority and funding.
As a health care administrator and hearing impaired individual I have profound interest in this research. Continuation of my professional life depends on adequate hearing and I am concerned about continuing hearing loss.
Does the researcher at Harvard have sufficient funds to continue this research on the fast track? The Federal government could do a great service to the hearing impaired by allocating funds for ramping up the efforts to utilize this research toward practical applications for humans. Certainly the number of Americans who suffer hearing loss warrents a major effort to aggressively continue this research
No thanks. I am happy to be deaf. They think they are gods and they can do anything about it. I think that it is good for people who lose the hearing while they can speak is a benefit from it, perhaps. For a deaf people who never speak since kids or born that way is not possible at all. Silly.
posted by Dorothea, Ph. D. on 10 Jan 2013 at 12:53 pm
The possibility of restoring hearing through introducing stem cells to replace lost hair cells has been a serious topic for some time now, but the the issue of growing new hair cells in the rows where they belong, as opposed to random, uncontrolled growth, has been a prevailing concern. Does the use of this drug, rather than stem cells, carry the same risk of cancerous growth? Or does this drug enable mice to regrow just what is needed where it's needed, as birds do? Does the regrowth cochlea look like a normal mouse cochlea?
'Growing Hearing Hairs May Reverse Deafness In Mice'
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