Hair cells are the sensors of the ear, picking up vibrations with tiny fibers that give the cells their name. Unfortunately, these cells are not replaced when lost in adult mammals. Loud noise, toxins, and some infectious diseases can cause sufficient loss of hair cells to induce deafness – a condition that currently lacks effective treatments. A sizable fraction of research into the causes of hearing loss has focused on hair cells in the ear, particularly with the growth of the regenerative medicine community. The restoration of lost cell populations is on the horizon, and hair cell regrowth is further advanced than many other lines of work in this field.
Is this approach useful for the types of hearing loss most frequently observed in older individuals, however? The results in today’s open access paper can be used to argue that hair cell regrowth may not be sufficient on its own. The authors present evidence for inner hair cells to remain largely intact, while the underlying issue is the death of neurons and their axons connecting these cells to the brain. Reintegration of new hair cells with the complex auditory system of the brain