Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research identifies promising route for treating age-related hearing loss

14.01.2005


Work should boost studies of hair-cell regeneration

Researchers have discovered that deletion of a specific gene permits the proliferation of new hair cells in the cochlea of the inner ear -- a finding that offers promise for treatment of age-related hearing loss. This type of hearing loss is caused by aging, disease, certain drugs, and the cacophony of modern life. It is the most common cause of hearing loss in older people.

The research team, which included Howard Hughes Medical Institute investigator David P. Corey, published their findings on January 13, 2005, in Science Express, which provides rapid electronic publication of selected Science publications. Zheng-Yi Chen, who is at Massachusetts General Hospital and Harvard Medical School, is the senior author of the article. He trained with Corey at Harvard Medical School. Other co-authors are from the University of Virginia School of Medicine, Tufts-New England Medical Center, and Northwestern University.



Hair cells in the cochlea detect sound by vibrating in response to sound waves, triggering nerve impulses that travel to the auditory region of the brain. Normally, humans are born with a complement of about 50,000 hair cells. But since the cells do not regenerate, the steady rate of hair-cell loss that can accompany aging produces significant hearing loss in about a third of the population by the time they reach 70-years-old.

Chen did a broad survey that examined patterns of gene expression during embryonic development of the balance organ of the inner ear. His results suggested that there might be a gene that produces a protein that acts as a permanent "brake" on hair-cell regeneration. That survey, which was done in mice, revealed that the retinoblastoma gene seemed to be particularly active during embryonic development.

At the same time, co-author Philip Hinds at Tufts-New England Medical Center had developed a knockout mouse lacking the retinoblastoma gene Rb1.

"He noticed that these mice ran in circles, and for an inner-ear biologist, a mouse running in circles immediately tells you that there is some problem with the vestibular system of the inner ear," said Corey. Thus, he said, Chen began a detailed study of the hair cells of the knockout mice. Those studies revealed that the mice without Rb1 had more hair cells than normal mice, and the cells were actively proliferating.

Corey and his colleagues then launched studies to determine whether the proliferating cells were, indeed, functional hair cells. They found that mechanically stimulating the cells generated an electrical signal characteristic of hair cells. Also, Corey and his colleagues found that the cells absorbed a fluorescent dye that only moves through the membrane channels of functional hair cells.

In further studies, Chen and his colleagues found that knocking out the Rb1 gene in cultured mature inner ear cells from mice triggered the cells to begin proliferating.

"This experiment demonstrated that it was a direct effect of the Rb gene and not some indirect effect during development that controlled proliferation of hair cells," said Corey. "So Zheng-Yi has found that deletion of this gene can allow functioning hair cells to continue to divide. They are no longer limited by whatever growth controls existed before. This work gives us an invaluable window into the control mechanism, which could lead to eventual clinical application in regenerating lost hair cells," said Corey.

According to Corey, the findings also have important implications for basic research. "A major obstacle to hair-cell research has been that, since there are not very many hair cells in the inner ear, it has been hard to get enough material for study," he said. "But with Zheng-Yi’s work, we now have the potential for generating cultured lines of hair cells for experiments."

"While we are very excited about the potential for hair-cell regeneration from this work, much basic research needs to be done," emphasized Corey. "Simply inactivating the Rb gene allows the hair cells to keep dividing and dividing, which might produce tumors in the inner ear. So, Zheng-Yi and his colleagues will be seeking ways to inactivate the gene only long enough to allow a clinically useful amount of proliferation, before turning the gene back on." The approach, he said, will require a greater understanding of the mechanisms controlling the Rb signaling pathway.

Jim Keeley | EurekAlert!
Further information:
http://www.hhmi.org

More articles from Life Sciences:

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

nachricht Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>