Researchers have discovered a vital mechanism responsible for stabilising the easily damaged inner ear hair cells. Once destroyed, these cochlear cells do not regenerate, leading to permanent hearing loss. These new findings could have a huge impact on hearing loss as we know it.
What are stereocilia and what do they do?
In the inner ear, there are 15,000 tiny, yet vital cochlear hair cells. They're responsible for receiving external noises which are then passed to the brain ready to be transformed into recognisable sounds. Each hair cell has a group of staircase-like architectural structures that also play a critical part in our hearing, commonly known as stereocilia. When stimulated by a sound wave, these microscopic projections move back and forth to open an important ion channel (the mechanotransduction channel) that allow calcium to flow into the cells.
A stereocilia study
Once destroyed, cochlear cells do not regenerate, leading to permanent hearing loss.
Researchers from the University of Kentucky and UK College of Medicine chose to further explore the link between calcium flow and stereocilia*. Because human stereocilia cells are deeply embedded into thick bone, they used rodents as the test subjects as theirs are much thinner and easier to access.
After isolating the inner ear tissues of the rodents, some were exposed to drugs that blocked the flow of calcium ions through the mechanotransduction channel while others were given drugs that altered the stereocilia structure.
For the rodents with blocked channels, it was discovered that the stereocilia retracted. This retraction is dependent on the calcium flow through the mechanotransduction channel. The other set of drugs also drastically altered the staircase-structured shape of the stereocilia, and when all drugs were removed from the hair cells, the stereocilia returned to their normal shape. Not only do these findings reveal the specific mechanism responsible for these results, it also shows that the calcium flow controls the structure of the stereocilia enormously.
This study, along with other recent findings help to pave the way for further research into molecular treatments to stabilise the stereocilia structure that could assist those living with hearing loss – an incurable condition.
There are one in six Australians living with some form of hearing loss* but thankfully, the industry experts Audika are on hand to offer advice and high-quality treatments for those with an auditory condition. To book your hearing assessment, call the team on 0800 001 726.