A new study shows that gene therapy could be the key to treating age- and trauma-related hearing loss. Emory University researchers have shown that introducing a gene called Atoh1 into the cochleae of young mice can induce the formation of extra sensory hair cells. These hair cells produce electrical signals in response to vibrations within the inner ear and connect with neurons like normal sensory hair cells. However, age may be a limitation of this treatment. After the mice are two weeks old, which is before puberty, introducing the gene has much less of an effect. "We've shown that hair cell regeneration is possible in principle," Ping Chen, associate professor of cell biology at Emory University School of Medicine, said. "In this paper, we have identified which cells are capable of becoming hair cells under the influence of Atoh1, and we show that there are strong age-dependent limitations on the effects of Atoh1 by itself."