In this paper, Drs. Miller and Alagramam offer further evidence for the existence of cochlear stem cells in the mouse cochlea by confirming the ability to form ‘stem cell?spheres in culture and by characterizing these cells in terms of neural and hair cell development using a panel of stem cell development and hair cell markers. The formation of spheres from early postnatal cochlear tissues and their expression of a wide range of developmental markers unique to hair cells confirm the possibility that self-supporting hair cell precursors exist in or can be derived from the postnatal mammalian cochlea.
Currently there are no clinical treatments to repair these hair cells vital to normal hearing. In the United States, 30% of people over the age of 65 have a handicapping hearing loss and of those, one in 500 people become deaf before reaching adulthood. In most cases, the target is the highly specialized hair cells. Docked inside the spiral duct of the human cochlea are ~15,000 hair cells, which are highly specialized neuroepithelial cells that enable us to hear a violin or a whisper. These hair cells differ in length by minuscule amounts and are set in motion by specific frequencies of sound. We hear this sound because this motion induces the hair cell to release an electrical impulse which passes along the auditory nerve to the brain. If the sound is too loud, the hair cells are damaged and no longer send signals to the brain. Severely damaged hair cells do not repair themselves nor do
Source:Case Western Reserve University