There may be new hope for people who are losing their hearing, thanks to research being conducted by scientists from the University of Southern California and Harvard University. They've developed a solution intended to stay put in the inner ear, where it will help repair cells.
Age and noise exposure-related hearing loss occurs due to the breakdown of hair-like sensory cells (known as hair cells) and bundles of neurons that transmit those cells' vibrations to the brain, along with the breakdown of synapses which connect the cells. The problem is, fluid is constantly flowing through the part of the inner ear where those cells and neurons are located – the cochlea, which is made of bone – meaning that any drugs placed there will be washed away.
With this in mind, the scientists designed a molecule which combines 7,8-dihydroxyflavone and bisphosphonate – the former mimics a protein critical for development and function of the nervous system, while the latter is a drug that sticks to bones.
In lab tests conducted on mouse ear tissue in a petri dish, the molecule not only stayed in place, but the neurons also responded to it by regenerating synapses that led to repair of both the hair cells and the neurons themselves.
It's still early days, though, as the solution has yet to be trialled on living animals. Nevertheless, the scientists believe it's a step in the right direction.
"We're not saying it's a cure for hearing loss," says USC's Prof. Charles E. McKenna. "It's a proof of principle for a new approach that's extremely promising. It's an important step that offers a lot of hope."
A paper on the research was recently published in the journal Bioconjugate Chemistry.