Loss of spiral ganglion cells as primary manifestation of aminoglycoside ototoxicity

Michihiko Sone, Patricia A. Schachern, Michael M. Paparella

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61 Scopus citations


Although pulmonary infections caused by Pseudomonas aeruginosa can hardly be eradicated in patients with cystic fibrosis (CF, the most common genetic disease among Caucasians), these patients are mainly treated with intravenous and nebulized tobramycin. Long-term treatment with tobramycin, however, may induce ototoxic effects. We assessed the clinical histories and postmortem temporal bones of six patients with CF for signs of this ototoxicity. Four bones showed typical manifestations of ototoxicity induced by aminoglycosides (AGs): loss of hair cells in the lower turns, and degeneration of ganglion cells. Six bones revealed no loss or scattered loss of hair cells, however, degeneration of the spiral ganglion cells was observed. This suggests that degeneration of the spiral ganglion may occur as a primary manifestation in some cases of ototoxicity due to aminoglycosides. Recent reports have shown that trophic factors (neurotrophins and acidic fibroblast growth factor) interacting with hair cells and the spiral ganglion protect the inner ear from damage. It may be that disturbances in supply of such trophic factors caused degeneration of ganglion cells without loss of hair cells in the cases we studied.

Original languageEnglish (US)
Pages (from-to)217-223
Number of pages7
JournalHearing Research
Issue number1-2
StatePublished - Jan 1 1998

Bibliographical note

Funding Information:
We express our gratitude to Sherry Fulton and Noriko Morizono for processing the temporal bone sections, and Ginny Hansen for editing the manuscript. This work was supported in part by NIH grant #P50DC-03093-01 from the National Institute on Deafness and Other Communication Disorders, the International Hearing Foundation, the Lions Club International, and the Yokoyama Clinical Pharmacology Foundation.


  • Cystic fibrosis
  • Degeneration
  • Ototoxicity
  • Spiral ganglion cell
  • Tobramycin


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