Chickens and restoring deafness: new studies


© L. Volckaert -

New studies have provided further understanding of what controls hair cell development and patterning – another step towards reversing hearing loss in humans.

Researchers from the University of Virginia School of Medicine in Charlottesville, VA (USA) and the National Institute on Deafness and Communication Disorders have explained, for the first time, what controls hair cell development and patterning by studying these cells in chickens. The MailOnline sums up their findings.

Unlike humans, chickens have stereocilia that can regenerate after damage that caused hearing loss. Jeffrey Corwin, from the university, explains that if a human and a hen were exposed to a sound loud enough to destroy their ability to hear a certain pitch, the outcomes would be very different. “We would lose the ability to hear that sound for the rest of our lives. The bird would also lose the ability, but within 10 days, it would have its cells back – they would hook back up to the nerves and within a few weeks its hearing would be back and almost indistinguishable from before.” High-pitched sounds are detected by cells with shorter hair bundles. They are located close to where sound enters the ear. Low-pitched sounds in contrast are detected by cells with taller hair bundles, located deeper in the ear. Until now, it was not clear how this pattern of individually distinct hair cells formed. Through their studies, the researchers have demonstrated that two specific molecules (Bmp7 and retinoic acid) guide cells to acquire location-specific attributes and to regenerate.

The hope is that understanding how these cells regenerate in chickens could open the way for replicating the process in humans, and eventually reversing hearing loss.

Source: MailOnline; Thiede BR et al. Retinoic acid signalling regulates the development of tonotopically patterned hair cells in the chicken cochlea. Nature Communications. 2014 May 20;5:3840.