Cotanche DA Laboratory of Cellular and Molecular Hearing Research Department of Otolaryngology Children’s Hospital Boston Massachusetts, USA
Department of Otology & Laryngology Harvard
Medical School Massachusetts, USA Division of Health Sciences and Technology
Harvard-MIT Boston-Cambridge Massachusetts, USA
Twenty years ago it was first
demon-strated that birds could regenerate their cochlear hair cells following
noise damage or aminoglycoside treatment.
An understanding of how this
structural and functional regeneration occurred might lead to the development
of thera-pies for treatment of sensorineural hear-ing loss in humans.
experiments have demonstrated that noise exposure and aminoglycoside treatment
lead to apoptosis of the hair cells.
In birds, this programmed cell death
induces the adja-cent supporting cells to undergo regeneration to replace the
lost hair cells.
Although hair cells in the mammalian cochlea undergo apoptosis
in response to noise damage and ototoxic drug treatment, the supporting cells
do not possess the ability to undergo regeneration.
However, current experiments
on genetic manipulation, gene therapy, and stem cell transplantation suggest
that regeneration in the mammalian cochlea may eventually be possible and may
one day provide a therapeutic tool for hear-ing loss in humans.
Learning outcomes: The reader should be able to:
(1) Describe the anatomy of the avian and mammalian cochlea, identify the
individual cell types in the organ of Corti, and distinguish major features
that participate in hearing function,
(2) Demonstrate a knowledge of how sound
damage and aminoglycoside poisoning induce apoptosis of hair cells in the
(3) Define how hair cell loss in the avian cochlea leads to
regeneration of new hair cells and distinguish this from the mammalian cochlea
where there is no regeneration fol-lowing damage, and
(4) Interpret the
potential for new approaches, such as genetic manipulation, gene therapy and
stem cell transplantation, could provide a therapeutic approach to hair cell
loss in the mammalian cochlea.
Fuente J Commun Disord. 2008; 41(5):