Can hearing loss be reversed in humans?

The most common type of hearing loss is sensorineural loss, which is caused by damage to cochlear hair cells. This condition is progressive because in humans and other mammals, the cochlear hair cells cannot regenerate once they are lost or damaged.

People who are frequently exposed to loud noises, such as musicians and construction workers, have the greatest risk of sensorineural hearing loss, but it can affect anyone over time. 

In a new study from the University of Rochester Medical Center, researchers are working to identify the mechanisms which may promote cochlear hair cell regeneration.

“We know from our previous work that expression of an active growth gene, called ERBB2, was able to activate the growth of new hair cells (in mammals), but we didn’t fully understand why,” said Dr. Patricia White. That particular study, led by Dr. Jingyuan Zhang, revealed that activating the growth gene ERBB2 pathway triggered a cascading series of cellular events through which cochlear support cells began to multiply and activate the creation of new sensory hair cells. 

“This new study tells us how that activation is happening – a significant advance toward the ultimate goal of generating new cochlear hair cells in mammals,” said Dr. White.

The team used single-cell RNA sequencing in mice to analyze cells with an overactive growth gene (ERBB2 signaling). The results showed that ERBB2 promoted cell development by triggering the expression of multiple proteins and promoted “mitosis” – the process by which one cell divides into two cells. 

“When we checked this process in adult mice, we were able to show that ERBB2 expression drove the protein expression of SPP1 that is necessary to activate CD44 and grow new hair cells,” said study first author Dr. Dorota Piekna-Przybylska. “This discovery has made it clear that regeneration is not only restricted to the early stages of development. We believe we can use these findings to drive regeneration in adults.”

“We plan to further investigation of this phenomenon from a mechanistic perspective to determine whether it can improve auditory function after damage in mammals. That is the ultimate goal,” said Dr. White.

The study is published in the journal Frontiers in Cellular Neuroscience.

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By Chrissy Sexton, Earth.com Editor

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