Researchers at USC and Harvard University have developed a new approach to repair ear cells: a potential remedy that could restore hearing for millions of elderly people and others who suffer from hearing loss.
This laboratory study shows the efficiency of a drug that zeroes in on damaged nerves and cells inside the ears.
It is a potential remedy for a problem that afflicts two thirds of people over 70 years.
“What’s new here is we figured out how to deliver a drug into the inner ear, where there is fluid constantly flowing, so it actually stays put and does what it’s supposed to do,” declared Charles E. McKenna, a corresponding author for the study and chemistry professor at the USC Dornsife College of Letters, Arts and Sciences.
The study opens up new horizons because researchers aim to deliver the drug directly into the cochlea, a snail-like structure in the inner ear, where sensitive cells send sounds to the brain. With age or in case of acoustic traumas, these sensory cells break down, as do the ribbon-like synapses that connect the cells. Damage to the inner ear can lead to “hidden hearing loss”, that is difficulty hearing whispers and soft sounds, particularly in noisy places. Then, the hearing loss becomes effective in all circumstances.
The researchers created a molecule combining 7,8-dihydroxyflavone, which mimics a protein critical for the development and function of the nervous system, and bisphosphonate, a type of drug that sticks to bones. They explained that the pairing of these two elements will deliver the revolutionary solution: neurons will respond to the molecule, which in turn will regenerate the synapses in the ear tissue, leading to the repair of the hair cells and neurons, which are crucial to hearing.
The study was conducted on animal tissues in a Petri dish. It has not yet been tested in living animals or humans. However, the researchers have faith it will work, because there are allegedly many similarities between the cells and mechanisms involved.
According to Charles McKenna, since the technique works in the laboratory, the results give “strong preliminary evidence” it could work in living creatures. They are already planning the next phase involving animals.
Hearing loss is projected to increase as the population ages and, according to previous research, it is expected to nearly double in 40 years. This new study gives hope to everyone.