Can you hear me now? Stem cells enhance hearing recovery

June 25, 2007

Tokyo, Japan -- Researchers have shown that bone marrow stem cells injected into a damaged inner ear can speed hearing recovery after partial hearing loss. The related report by Kamiya et al, “Mesenchymal stem cell transplantation accelerates hearing recovery through the repair of injured cochlear fibrocytes,” appears in the July issue of The American Journal of Pathology.

Hearing loss has many causes, including genetics, aging, and infection, and may be complete or partial. Such loss may involve damage to inner ear cells called cochlear fibrocytes, which are fundamental to inner ear function. Some natural regeneration of these cells can occur after acute damage, leading to partial recovery of temporary hearing loss. But could such restoration be enhanced by using bone marrow stem cells, which can differentiate into various tissue-specific cell types"

Dr. Tatsuo Matsunaga of National Tokyo Medical Center pursued this hypothesis by utilizing a well-characterized rat model of drug-induced hearing loss. This model specifically destroys cochlear fibrocytes and leads to acute hearing loss. Although partial recovery occurs over many weeks, high-frequency hearing remains extremely diminished. Using this system, the investigators examined whether direct administration of stem cells into the inner ear could restore the cochlear fibrocyte population and aid hearing recovery.

Stem cells injected into the inner ear survived in half of the injured rats, where they migrated away from the site of injection toward the injured region within the inner ear. These stem cells divided in the new environment and expressed several proteins necessary for hearing, suggesting tissue-specific differentiation. Further, transplanted cells that migrated to the damaged area of the inner ear displayed shape similar to that of cochlear fibrocytes.

Importantly, transplanted rats exhibited faster recovery from hearing loss, particularly in the high frequency range, which is difficult to restore by natural regeneration. Stem cell migration into the damaged area of the inner ear improved hearing of high frequency sound (40 kHz) by 23% compared to natural recovery in untreated animals.

This is the first report to demonstrate hearing recovery following stem cell transplantation into the inner ear. “Cell therapy targeting regeneration of the cochlear fibrocytes may therefore be a powerful strategy to cure sensorineural hearing loss that cannot be reversed by current therapies,” state Dr. Matsunaga and colleagues.

Source: American Journal of Pathology

Explore further: Researchers listen to zebrafish to understand human hearing loss

Related Stories

Gene may hold key to hearing recovery

April 24, 2017

Researchers have discovered that a protein implicated in human longevity may also play a role in restoring hearing after noise exposure. The findings, where were published in the journal Scientific Reports, could one day ...

Study shows hearing tests miss common form of hearing loss

April 18, 2017

Traditional clinical hearing tests often fail to diagnose patients with a common form of inner ear damage that might otherwise be detected by more challenging behavioral tests, according to the findings of a University at ...

Hearing tests may miss common form of hearing loss

May 2, 2017

(HealthDay)—Commonly used hearing tests often fail to detect a prevalent form of inner ear damage, according to an experimental study published online recently in Frontiers in Neuroscience.

Recommended for you

Scientists use algorithm to peer through opaque brains

June 26, 2017

Trying to pinpoint signals from individual neurons within a block of brain tissue is like trying to count headlights in thick fog. A new algorithm, developed by researchers based at The Rockefeller University, brings this ...

Tiny bubbles offer sound solution for drug delivery

June 25, 2017

Your brain is armored. It lives in a box made of bones with a security system of vessels. These vessels protect the brain and central nervous system from harmful chemicals circulating in the blood. Yet this protection system—known ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.