American researchers plan to examine how calcium overload from noise exposure might damage cochlear hair cells, contributing to hearing loss.
The aim is to identify novel therapeutic targets to treat it.
With a new five-year, $3.2 million grant from the National Institute on Deafness and Other Communications Disorders, the researchers from Case Western Reserve University and Mass Eye and Ear will study what causes acquired hearing loss (AHL) and seek new ways to protect against it.
They said that although hearing aids could help, AHL had no known cure and, in many cases, scientists were still unsure of its exact cause.
“We anticipate that if we are successful, this could point to new strategies to preserve human hearing by regulating mitochondrial calcium levels,” said Assistant Professor Ruben Stepanyan from the Department of Otolaryngology at Case Western Reserve School of Medicine.
He said an important factor in hearing was the health of cochlear hair cells — sensory cells in the inner ear that detect sound vibrations and send electric signals to the brain. These cells are packed with mitochondria, or microscopic energy-producing components.
Hearing loss may result from damage caused by malfunctioning mitochondria, according to previous peer-reviewed research.
A/Prof Stepanyan said hair-cell health depended on balanced calcium levels regulated, in part, by mitochondria. Loud noises could cause calcium levels to rise too high, stressing the cochlear hair cells.
The study will examine how calcium overload from noise exposure might damage cochlear hair cells contributing to hearing loss and identify novel therapeutic targets to treat it.
Researchers will use mouse models more prone to calcium overload and early hearing loss to evaluate how overstimulation from loud sounds affects the structure and function of cochlear hair cells.
Advanced three-dimensional imaging technology and novel machine-learning-based 3D data analysis approaches will examine the structure of mitochondria in the cells to understand how they change under stress.
Researchers will then test whether preventing calcium overload in mitochondria can protect hearing by testing other types of mouse models with reduced mitochondrial calcium to learn if they may be more resistant to noise damage.
“The ultimate goal is to find ways to prevent hearing loss related to noise exposure and aging, which could help millions of people protect their hearing as they age,” said Assistant Professor of otolaryngology at Harvard Medical School, Artur Indzhykulian, also an assistant scientist at Mass Eye and Ear’s Eaton-Peabody Laboratories.
Case Western Reserve is a research university and Massachusetts Eye and Ear is an international centre for treatment and research and a teaching hospital of Harvard Medical School.
