Regeneration of the inner ear hair cells

Hearing loss is a major health problem affecting millions of people: the World Health Organization (WHO, 2002) estimated that, 250 million people suffered from disabling hearing loss and that two-thirds of them live in the developing world (Holley, 2005). In addition, 1 in 1000 children are born with severe to profound hearing loss, and people 70 years or older have a 60% chance of suffering from hearing loss of at least 25 decibels (dB) (Shim, 2006). Hair cells (HCs), which are the sensory receptors for hearing, equilibrium and motion detection, are located in the auditory, vestibular and lateral line organs (Avallone et al., 2003).