Scientists have found a cocktail of drugs that can regenerate hair cells in the inner ear, an advance that may pave the way for new treatments against hearing loss.
Each human is born with about 15,000 hair cells per ear, these cells detect sound waves and translate them into nerve signals that allow us to hear speech, music and other everyday sounds. Once damaged, these cells cannot regrow.
Researchers have discovered a combination of drugs that expands the population of progenitor cells or supporting cells in the ear and induces them to become hair cells, that may offer a potential way to treat hearing loss.
“Hearing loss is a real problem as people get older. It’s very much of an unmet need, and this is an entirely new approach,” said Robert Langer, a professor at Massachusetts Institute of Technology (MIT) in US.
Carrying forward a previous study that found that structural support in the cochlea express provide some of the same surface proteins as intestinal stem cells. The researchers decided to explore whether the same approach would work on supporting cells.
They exposed cells from a mouse cochlea, grown in a lab dish, to molecules that stimulate the Wnt pathway, which makes the cells multiply rapidly. “We used small molecules to activate the supporting cells so they become proliferative and can generate hair cells,” said Xiaolei Yin, an instructor at Brigham and Women’s Hospital (BWH).
Once they had a large pool of immature progenitor cells, the researchers added another set of molecules that provoked the cells to differentiate into mature hair cells, producing 60 times more mature hair cells than previously used techniques.
Since the treatment involves a simple drug exposure, it will be easier to administer it to humans, with the help of an injection according to the researchers.
“We hope that our work will allow other scientists to pursue studies of supporting cells and hair cells that have not been possible because such limited quantities of hair cells were available,” said Will McLean from MIT.