Sensory hair cells regenerated, hearing restored in mammal ear

Novel findings may lead to cures for deafness

2013-01-09

(Press-News.org) Boston (Jan. 9, 2013) — Hearing loss is a significant public health problem affecting close to 50 million people in the United States alone. Sensorineural hearing loss is the most common form and is caused by the loss of sensory hair cells in the cochlea. Hair cell loss results from a variety of factors including noise exposure, aging, toxins, infections, and certain antibiotics and anti-cancer drugs. Although hearing aids and cochlear implants can ameliorate the symptoms somewhat, there are no known treatments to restore hearing, because auditory hair cells in mammals, unlike those in birds or fish, do not regenerate once lost. Auditory hair cell replacement holds great promise as a treatment that could restore hearing after loss of hair cells. In the Jan. 10 issue of Neuron, Massachusetts Eye and Ear and Harvard Medical School researchers demonstrate for the first time that hair cells can be regenerated in an adult mammalian ear by using a drug to stimulate resident cells to become new hair cells, resulting in partial recovery of hearing in mouse ears damaged by noise trauma. This finding holds great potential for future therapeutic application that may someday reverse deafness in humans. "Hair cells are the primary receptor cells for sound and are responsible for the sense of hearing," explains senior author, Dr. Albert Edge, of Harvard Medical School and Mass. Eye and Ear. "We show that hair cells can be generated in a damaged cochlea and that hair cell replacement leads to an improvement in hearing." In the experiment, the researchers applied a drug to the cochlea of deaf mice. The drug had been selected for its ability to generate hair cells when added to stem cells isolated from the ear. It acted by inhibiting an enzyme called gamma-secretase that activates a number of cellular pathways. The drug applied to the cochlea inhibited a signal generated by a protein called Notch on the surface of cells that surround hair cells. These supporting cells turned into new hair cells upon treatment with the drug. Replacing hair cells improved hearing in the mice, and the improved hearing could be traced to the areas in which supporting cells had become new hair cells. "The missing hair cells had been replaced by new hair cells after the drug treatment, and analysis of their location allowed us to correlate the improvement in hearing to the areas where the hair cells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," Dr. Edge said. This is the first demonstration of hair cell regeneration in an adult mammal. "We're excited about these results because they are a step forward in the biology of regeneration and prove that mammalian hair cells have the capacity to regenerate," Dr. Edge said. "With more research, we think that regeneration of hair cells opens the door to potential therapeutic applications in deafness."

### Funding sources: This work was supported by grants RO1 DC007174, R21 DC010440 and P30 DC05209 from the National Institute on Deafness and other Communicative Disorders (NIDCD); by the Tillotson Corporation, the Shulsky Foundation, and Robert Boucai; by the Mochida Memorial Foundation for Medical and Pharmaceutical Research; and by Grants for International Activities in Life Sciences and Medicine, Keio University Medical Science Fund.

A full list of authors and affiliations and full acknowledgement of all contributors is available in the pdf of the paper, "Notch Inhibition Induces Cochlear Hair Cell Regeneration and Recovery of Hearing after Acoustic Trauma."

About Massachusetts Eye and Ear Mass. Eye and Ear clinicians and scientists are driven by a mission to find cures for blindness, deafness and diseases of the head and neck. After uniting with Schepens Eye Research Institute in 2011, Mass. Eye and Ear in Boston became the world's largest vision and hearing research center, offering hope and healing to patients everywhere through discovery and innovation. Mass. Eye and Ear is home to the Eaton-Peabody Laboratories, the largest collection of basic hearing laboratories. Mass. Eye and Ear is a Harvard Medical School teaching hospital and trains future medical leaders in ophthalmology and otolaryngology, through residency as well as clinical and research fellowships. Internationally acclaimed since its founding in 1824, Mass. Eye and Ear employs full-time, board-certified physicians who offer high-quality and affordable specialty care that ranges from the routine to the very complex. U.S. News & World Report's "Best Hospitals Survey" has consistently ranked the Mass. Eye and Ear Departments of Otolaryngology and Ophthalmology as top five in the nation.

ELSE PRESS RELEASES FROM THIS DATE:

Not all stem cells are equally efficient for use in regenerative medicine

2013-01-09

Scientists at the University of Granada and Alcalá de Henares University have found out that not all isolated stem cells are equally valid in regenerative medicine and tissue engineering. In a paper recently published in the prestigious journal Tissue Engineering the researchers report that, contrary to what was thought, only a specific group of cord blood stem cells (CB-SC) maintained in culture are useful for therapeutic purposes. At present, CB-SCs are key to regenerative medicine and tissue engineering. From all types of CB-SC those called "Wharton's jelly stem cells ...

Passive smoking increases risk of severe dementia, according to study in China

2013-01-09

Passive smoking, also known as 'second-hand' smoke or environmental tobacco smoke (ETS), is known to cause serious cardiovascular and respiratory diseases, including coronary heart disease and lung cancer. However, until now it has been uncertain whether ETS increases the risk of dementia, mainly due to lack of research. Previous studies have shown an association between ETS and cognitive impairment, but this is the first to find a significant link with dementia syndromes. The study, published in Occupational and Environmental Medicine, is a collaboration between scientists ...

Multiple sclerosis drug may one day treat colorectal cancer

2013-01-09

After uncovering a mechanism that promotes chronic intestinal inflammation and the development of colorectal cancer, scientists from Virginia Commonwealth University Massey Cancer Center have found that fingolimod, a drug currently approved for the treatment of multiple sclerosis, could potentially eliminate or reduce the progression of colitis-associated cancer (CAC). The study, published online in the journal Cancer Cell, was led by Sarah Spiegel, Ph.D., Mann T. and Sara D. Lowry Chair in Oncology, co-leader of the Cancer Cell Signaling program at VCU Massey Cancer ...

Poll of psychologists cites emotions as top obstacle to successful weight loss

2013-01-09

WASHINGTON – When it comes to losing weight, a popular New Year's resolution for many, people often focus on eating less and exercising more. But results of a new survey of psychologists suggest dieters should pay attention to the role emotions play in weight gain and loss if they hope to succeed. The survey, conducted by the Consumer Reports National Research Center, asked more than 1,300 licensed psychologists how they dealt with clients' weight and weight loss challenges. When asked which strategies were essential to losing weight and keeping it off, psychologists ...

Low extinction rates made California a refuge for diverse plant species

2013-01-09

SANTA CRUZ, CA--The remarkable diversity of California's plant life is largely the result of low extinction rates over the past 45 million years, according to a new study published in the journal Evolution. Although many new species have evolved in California, the rate at which plant lineages gave rise to new species has not been notably higher in California than elsewhere, researchers found. Botanists have long recognized California as a biodiversity hotspot. With more than 5,500 native plant species, 40 percent of which are "endemic" (occurring nowhere else), California ...

NTU study looks at national attitudes towards homosexuals

2013-01-09

Singapore, 9 January 2013 Attitudes of Singaporeans and permanent residents toward gays and lesbians although sharply polarised and predominantly negative, have shifted slightly over a five-year span to become a little more favourable. This was found by a research team from the Wee Kim Wee School of Communication and Information at Nanyang Technological University (NTU). A nationally representative survey found that people with higher levels of education and freethinkers tend to have more positive attitudes. Those who had higher interpersonal contact with gay men ...

How the brain stays receptive

2013-01-09

The channel protein Pannexin1 keeps nerve cells flexible and thus the brain receptive for new knowledge. Together with colleagues from Canada and the U.S., researchers at the Ruhr-Universität Bochum led by the junior professor Dr. Nora Prochnow from the Department of Molecular Brain Research describe these results in PLoS ONE. In the study, mice comprising no Pannexin1 in memory-related brain structures displayed symptoms similar to autism. Their nerve cells lacked synaptic plasticity, i.e. the ability to form new synaptic contacts or give up old contacts based on the level ...

Researchers reveal most effective treatment for common kidney disorder

2013-01-09

The results of a pioneering UK-wide clinical trial that compared treatments for patients with a common type of kidney disease has found one to be significantly more effective. The results of the study, published online in The Lancet today [9 Jan], will be recommended to clinicians worldwide as the most effective approach to treating the condition. The Medical Research Council-funded study, led by researchers from the University of Bristol's Academic Renal Unit based in Southmead Hospital, compared three treatment approaches in a type of kidney disorder known as 'membranous ...

New study identifies significance of co-infection in disease control

2013-01-09

The new study analyses data from school aged children in Tanzania infected with the most common forms of worms. It was found that infection by one parasitic species actually changes the risk of catching another, over and above other risk factors. The study is the first to look at the significance of infection with one disease as a risk for further infections (i.e. co-infection). The findings could help us better understand the importance of co-infection as a risk, and could help inform disease control strategies. Traditionally, co-infection, where the person or ...

The Teotihuacans exhumed their dead and dignified them with make-up

2013-01-09

In collaboration with the National University of Mexico, a team of Spanish researchers has analysed for the first time remains of cosmetics in the graves of prehispanic civilisations on the American continent. In the case of the Teotihuacans, these cosmetics were used as part of the after-death ritual to honour their city's most important people. A research team from the Polytechnic University of Valencia and the University of Valencia has studied various funerary samples found in urns in the Teotihuacan archaeological site (Mexico) that date from between 200 and 500 ...

Sensory hair cells regenerated, hearing restored in mammal ear

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: