Generation of hair cells: a monumental breakthrough.

Human hearing loss is one of the most common and disabling of all chronic diseases. The major reason that hearing loss remains permanent once it has occurred is the inability of the cochlear sensory epithelium to replace lost hair cells. Drs. Li, Roblin, Liu, and Heller, from the Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton-Peabody Laboratory, The Massachusetts Eye and Ear Infirmary (MEEI), Boston, report the first confirmed generation of hair cells by stepwise differentiation from embryonic stem cells. (1)

In an earlier paper by Li, Liu, and Heller, it was observed that inner ear stem cells of the adult mouse are pluripotent and are capable of differentiating into hair-cell-like cells, implying a possible use of such cells for the replacement of lost inner ear sensory cells. (2)

In late October 1 had the privilege of visiting the Department of Otolaryngology at MEEI, which is headed by Joseph B. Nadol, Jr., MD, to observe my gracious host Dennis Poe, MD, perform surgery for chronic serous otitis media. I also was fortunate to visit MEEI's Eaton-Peabody Laboratory, which is under the direction of M. Charles Liberman, PhD, and see many of the exciting projects being studied there, including those of noise-induced hearing loss led by Stephane F. Maison, PhD.

Stefan Heller, PhD. who heads a nine person basic research team at the Eaton-Peabody Laboratory, showed me convincing evidence, using monoclonal antibody markers, that his group had deliberately generated hair cells from stem-cell-derived inner ear progenitor cells in tissue culture and in vivo, by placing mouse tuner ear stem cells in the otic vesicles of stage 16 to 17 chick embryos (figure). Heller's laboratory generated tuner ear progenitor cells from either adult stem cells found in the mouse utricular sensory epithelium (2) or by stepwise guidance from mouse embryonic stem cells with specific growth factors. (1)

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This research success marks a major breakthrough toward medicine's eventual ability to restore missing hair cells and lost hearing of patients. A new chapter in otologic treatment has been opened. Congratulations to the investigators from Harvard.

References

(1.) Li H, Roblin G, Liu H. Heller S. Generation of hair cells by stepwise differentiation of embryonic stem cells. Proc Natl Acad Sci U S A:100:13495 500.

(2.) Li H, Liu H, Heller S. Pluripotent stem cells from the adult mouse inner ear. Nature Medicine 2003;9:1293-99.

JACK L. PULEC, MD

Editor-in-Chief

EAR, NOSE & THROAT JOURNAL