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Researchers hope they will be able to one day treat deafness with stem cells. |
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.
They used
stem cells from a human embryo, which are capable of becoming any other type of
cell in the human body from nerve to skin, muscle to kidney.
A chemical
soup was added to the stem cells that converted them into cells similar to the
spiral ganglion neurons. These were then delicately injected into the inner
ears of 18 deaf gerbils.
Over 10
weeks the gerbils' hearing improved. On average 45% of their hearing range was
restored by the end of the study.
Dr Marcelo
Rivolta said: "It would mean going from being so deaf that you wouldn't be
able to hear a lorry or truck in the street to the point where you would be
able to hear a conversation.
"It is
not a complete cure, they will not be able to hear a whisper, but they would
certainly be able to maintain a conversation in a room."
About a
third of the gerbils responded really well to treatment with some regaining up
to 90% of their hearing, while just under a third barely responded at all.
Gerbils
were used as they are able to hear a similar range of sounds to people, unlike
mice which hear higher-pitched sounds.
The
researchers detected the improvement in hearing by measuring brainwaves. The
gerbils were also tested for only 10 weeks. If this became a treatment in
humans then the effect would need to be shown over a much longer term.
There are
also questions around the safety and ethics of stem cell treatments which would
need to be addressed.
'Tremendously
encouraging'
Prof Dave
Moore, the director of the Medical Research Council's Institute of Hearing
Research in Nottingham, told the BBC: "It is a big moment, it really is a
major development."
However, he
cautioned that there will still be difficulties repeating the feat in people.
"The
biggest issue is actually getting into the part of the inner ear where they'll
do some good. It's extremely tiny and very difficult to get to and that will be
a really formidable undertaking," he said.
Dr Ralph
Holme, head of biomedical research for the charity Action on Hearing Loss,
said: "The research is tremendously encouraging and gives us real hope
that it will be possible to fix the actual cause of some types of hearing loss
in the future.
"For
the millions of people for whom hearing loss is eroding their quality of life,
this can't come soon enough."
Related Article:
"Recalibration of Knowledge" – Jan 14, 2012 (Kryon channelled by Lee Carroll) - (Subjects: Channelling, God-Creator, Benevolent Design, New Energy, Shift of Human Consciousness, (Old) Souls, Reincarnation, Gaia, Old Energies (Africa,Terrorists, Cuba, Iran, North Korea, Venezuela ... ), Weather, Rejuvenation, Akash, Nicolas Tesla / Einstein, Cold Fusion, Magnetics, Lemuria, Atomic Structure (Electrons, Particles, Polarity, Self Balancing, Magnetism), Entanglement, "Life is necessary for a Universe to exist and not the other way around", DNA, Humans (Baby getting ready, First Breath, Stem Cells, Embryonic Stem Cells, Rejuvenation), Global Unity, ... etc.) - (Text Version)
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