Hair cell re-growth.

Hair cell loss is usually a function of age, noise, ototoxic drugs and genetics. Therapeutic strategies fall into two categories: protection and regeneration. Protective methods include targeted application of growth factors and other agents to promote cell survival, and systemic application of drugs to prevent activation of programmed cell death. These strategies are related to treatments that cause predictable damage, such as the use of aminoglycoside antibiotics. The challenge of hair cell regeneration is more difficult. Instead of preventing cell loss, we must consider methods of stimulating cell division and hair cell differentiation from existing cells. We need to know much more about the molecular mechanisms that govern these processes so that we can identify potential targets for specific drugs or gene therapies. One method of approaching the issue is to combine in vitro models of developing hair cells with genomic and proteomic technologies. The benefits of hair cell re-growth may not be limited to full replacement of pre-existing cells. Surrogate hair cells may help to maintain cochlear innervation, even if they do not detect sound, and this property could be harnessed to improve the performance of cochlear implants.