According to the World Health Organization, by 2050, 1.5 billion people are expected to have some degree of hearing loss. Many of these cases stem from damage to the delicate inner ear hair cells that transmit sound signals to the brain.
When these cells are damaged due to age, noise exposure or illness, they do not regenerate, leading to permanent hearing loss. However, new research using gene therapy within mice suggests there could be a solution someday in the future. In the study, scientists developed a gene therapy to repair the inner ear hair cells and restored hearing in mice by utilizing the brain’s natural fluids and a little-known pathway to the cochlea.
The Role of Hair Cells in Hearing Loss
Hair cells in the cochlea transform vibrations into signals that the brain interprets as sound. When these cells are destroyed, hearing loss occurs. Currently, options like hearing aids or cochlear implants assist by amplifying sound or stimulating the auditory nerve, but they do not restore natural hearing. Because of the limitations to restoring hearing, researchers have explored other solutions.
About the Research
What allowed this research to work is the discovery of a pathway within the cochlea called the cochlear aqueduct, that allows gene therapy to be administered efficiently in young mice. Researchers found that the gene therapy can be delivered through this natural opening in the cochlea, which connects to the brain’s cerebrospinal fluid. By injecting the therapy into the brain’s natural fluids via this pathway, it can travel to the cochlea and reach the hair cells that need repair.
In young mice, this method has been successful in regenerating damaged hair cells and improving hearing function. The cochlea in young mice remains more accessible because it is not yet covered by bone, allowing the gene therapy to reach the targeted cells without invasive procedures.
Challenges of Cochlear Bone Formation with Age
However, as mammals age, including humans, the cochlea becomes encased in bone, which poses a challenge for delivering gene therapy later in life. This natural process creates a barrier that makes it more difficult to access the inner ear without surgery.
In older patients, this limits the effectiveness of therapies that rely on natural fluid pathways to reach the inner ear. Therefore, the research suggests a similar method could potentially be developed to primarily address progressive genetic hearing loss.
This new research into gene therapy for hearing loss has opened a door for methods to potentially restoring auditory function. The discovery of administering gene therapy efficiently through natural body fluids marks a major step forward in the fight against hearing loss.
To learn more about this study or to schedule a hearing evaluation for you or a loved one, contact San Francisco Audiology today.