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Deaf Online _ Research General Discussion _ OHSU Grows Hair Cells Involved in Hearing

Posted by: HHIssues Tue Sep 30, 2008, 06:56 AM

source: [HOH-LD-News] Volume 36 Issue 13

- Article 3: OHSU Grows Hair Cells Involved in Hearing

Editor: For a while it seemed like we were seeing frequent
breakthroughs in the haircell regeneration quest, but then we
went for quite a long time with little news. Today we learn that
scientists at Oregon Health & Science University (OHSU) have
successfully grown haircells in the developing inner ears of
prenatal mice by inserting a gene called Atoh1. It sounds to me
like we're still a bunch of breakthroughs away from commercial
haircell generation, but we are a bit closer!

Here's the notice from OHSU.


Successful production of functional sensory hair cells in the
inner ears of mice suggests that a new therapy to regain hearing
may be possible.

Oregon Health & Science University scientists have successfully
produced functional auditory hair cells in the cochlea of the
mouse inner ear. The breakthrough suggests that a new therapy
may be developed in the future to successfully treat hearing
loss. The results of this research will be published online this
week by the journal Nature.

"One approach to restore auditory function is to replace
defective cells with healthy new cells," said John Brigande,
Ph.D., an assistant professor of otolaryngology at the Oregon
Hearing Research Center in the OHSU School of Medicine. "Our
work shows that it is possible to produce functional auditory
hair cells in the mammalian cochlea."

The researchers specifically focused on the tiny hair cells
located in a portion of the ear's cochlea called the organ of
Corti. It has long been understood that as these hair cells die,
hearing loss occurs. Throughout a person's life, a certain
number of these cells malfunction or die naturally leading to
gradual hearing loss often witnessed in aging persons. Those who
are exposed to loud noises for a prolonged period or suffer from
certain diseases lose more sensory hair cells than average and
therefore suffer from more pronounced hearing loss.

Brigande and his colleagues were able to produce hair cells by
transferring a key gene, called Atoh1, into the developing inner
ears of mice. The gene was inserted along with green florescent
protein (GFP) which is the molecule that makes a species of
jellyfish glow. GFP is often used in research as a "marker" that
a scientist can use to determine, in this case, the exact
location of the Atoh1 expression. Remarkably, the gene transfer
technique resulted in Atoh1 expression in the organ of Corti,
where the sensory hair cells form.

Using this method, the researchers were able to trace how the
inserted genetic material successfully led to hair cell
production resulting in the appearance of more hair cells than
are typically located in the ears of early postnatal mice.
Crucially, Dr. Anthony Ricci, associate professor of
otolaryngology at the Stanford University School of Medicine,
demonstrated that the hair cells have electrophysiological
properties consistent with wild type or endogenous hair cells,
meaning that the hair cells appear to be functional. Based on
these data, the scientists concluded that Atoh1 expression
generates functional auditory hair cells in the inner ear of
newborn mammals.

"It remains to be determined whether gene transfer into a deaf
mouse will lead to the production of healthy cells that enable
hearing. However, we have made an important step toward defining
an approach that may lead to therapeutic intervention for
hearing loss," Brigande said.

About the Oregon Hearing Research Center at OHSU

The Oregon Hearing Research Center at the Oregon Health &
Science University is comprised of over 50 scientists and
support staff engaged in basic and applied research into the
causes and treatment of hearing disorders. Established in 1966
by Jack Vernon, Ph.D., the Center is currently under the
direction of Alfred Nuttall, Ph.D. Sources of research support
come from the National Institutes of Health and private hearing
research organizations.

About OHSU

Oregon Health & Science University is the state's only health
and research university, and Oregon's only academic health
center. OHSU is Portland's largest employer and the fourth
largest in Oregon (excluding government), with 12,400 employees.
OHSU's size contributes to its ability to provide many services
and community support activities not found anywhere else in the
state. It serves patients from every corner of the state, and is
a conduit for learning for more than 3,400 students and
trainees. OHSU is the source of more than 200 community outreach
programs that bring health and education services to every
county in the state.

As a leader in research, OHSU earned $307 million in research
funding in fiscal year 2007. OHSU serves as a catalyst for the
region's bioscience industry and is an incubator of discovery,
averaging one new breakthrough or innovation every three days,
with more than 4,100 research projects currently under way. OHSU
disclosed 132 inventions in 2007 alone, and OHSU research
resulted in 33 new spinoff companies since 2000, most of which
are based in Oregon.

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