Scientists have used gene therapy on embryos to grow hair cells with the potential to reduce hearing loss in adults. This test was done on lab mice, not humans, mind you.
Sensory hair cells inside the cochlea, the auditory portion of the inner ear, convert sound waves into electrical pulses which are then delivered to the brain.
The loss of these cells and the neurons they contain is the most common cause of hearing impairment and deafness.
At birth, humans have about 30,000 hair cells, which can be damaged by infections, ageing, genetic diseases, loud noise, or medical treatments.
Ususally, the damaged hair cells do not regrow in humans. But recent research has kindled hope that nerve deafness may one day be curable.
Experiments have shown that implanting a gene known as Atoh1 into the inner ear of a mouse embryo caused non-sensory cells to become the sensory hair cells.
Earlier research had hinted that this would happen, but this was the first time that working hairs werre created by gene therapy.
The production of the working hair cells in a mouse embryo are a crucial step toward using similar therapies in human patients.