2004 Fiscal Year Final Research Report Summary
Recovery from severe hearing impairment by regeneration of inner ear sensory organs
| Project/Area Number |
14207068
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Kyoto University |
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Principal Investigator |
ITO Juichi Kyoto University, Graduate School of medicine, Professor, 医学研究科, 教授 (90176339)
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| Co-Investigator(Kenkyū-buntansha) |
TSUJI Jun Kyoto University, Graduate School of medicine, Lecturer, 医学研究科, 講師 (30252448)
NAKAGAWA Takayuki Kyoto University, Graduate School of medicine, Assistant Professor, 医学研究科, 助手 (50335270)
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| Project Period (FY) |
2002 – 2004
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| Keywords | hearing impairment / regeneratio / transplantation / inner ear / hair cell / spiral ganglion cell / stem cell / nerve growth factor |
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| Research Abstract |
Our final goal is to establish a therapeutic strategy for inner ear diseases, especially for severe sensorineural hearing impairment. There are more than 3 hundred thousand deaf or highly hearing impaired people in Japan. To recover hearing ability of those deaf people has been one of the most important themes in the field of Otolaryngology. Dysfunctions of several regions in the cochlea, such as spiral ganglion cells, sensory hair cells, and cochlear wall, cause hearing disability. Among them dysfunction of sensory hair cells and the spiral ganglion cells are the most important factors. If the hair cells or spiral ganglion cells regenerate and recover function, hearing ability may recover.
The first experiments have been attempted in the auditory system, involving repair to the central auditory pathway using rats. Embryonic brain tissue was placed into a lesion in the ventral cochlear tract, resulting the regeneration of the ventral cochlear tract and associated recovery of the ABR.
Then, we examined the potential of transplantation approaches for inner ear diseases. The targets for transplantation approaches included sensory hair cells(HCs) and spiral ganglions(SGs). Mice and rats were used as experimental animals. Embryonic stem cells(ES), Neural stem(NS) cells and mesenchymal stem(MS) cells were used as donors. Cell transplantation into the inner ear was performed through the round window, cochlear lateral wall, or semicircular canal. These donor cells survived in various regions of the inner ear including the sensory epithelia. This indicates that transplantation approach can be utilized for protection of HCs and SGs from cell death. Consequently, transplantation approaches have the potential for treatment of inner ear diseases
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