GENETICS
A team of Harvard Medical School scientists say they’ve come up with a new drug cocktail of molecules that they say can successfully regenerate the hair cells in the inner ear that enable hearing — a potentially groundbreaking treatment for hearing loss.
As detailed in a new paper published in the Proceedings of the National Academy of Sciences, the researchers coaxed the hair cells to regrow in mice by reprogramming genetic pathways in the inner ear.
They’re now hoping the study could lay the groundwork for future clinical trials to develop a treatment for humans suffering from hearing loss. It’s a big “if,” sure, but also a tantalizing ray of hope for people struggling with their hearing.
“These findings are extremely exciting because throughout the history of the hearing loss field, the ability to regenerate hair cells in an inner ear has been the holy grail,” said research team led Zheng-Yi Chen, an HMS associate professor, in a statement. “We now have a drug-like cocktail that shows the feasibility of an approach that we can explore for future clinical applications.”
Unlike certain species of fish, birds, or reptiles, humans do not have the ability to regenerate hair cells, which are like biological microphones responsible for passing sound signals from the inner ear to the brain.
In an earlier study, also on mice, Chen’s team was able to make other types of cells divide and develop the characteristics of hair cells.
This latest research builds on that success by activating these same pathways with the use of newly developed chemical compounds.
By using molecules called “small interfering RNAs” (siRNAs), the team was able to remove genes that suppressed the activation of a genetic pathway, which allows for the growth of hair cells in the inner ear.
“Think about a brake when driving a car,” Chen explained in the statement. “If the brake is always engaged, you can’t drive. We found an siRNA that could remove the brake in this genetic pathway.”
By delivering their newly developed drug cocktail straight into the inner ear of adult mice, they found that the mice were able to regenerate new hair cells that appear to be fully functional.
Before testing out the treatment on humans, the researchers are planning to test it on larger animals first.
But if proven successful, the research could have a profound impact on individuals who have lost part of their hearing.
“My colleagues and I frequently are contacted by people with hearing loss who are desperate for effective treatments,” Chen said in the statement. “If we can combine a surgical procedure with a refined gene therapy delivery method, we hope we can achieve our number one goal of bringing a new treatment into the clinic.”
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