Efficacy of Long-Term Cochlear Implantation of Dexamethasone-Eluting Electrodes

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K11323
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Otorhinolaryngology
• Research Institution: Shinshu University
• Principal Investigator: TAKUMI YUTAKA 信州大学, 学術研究院医学系, 教授 (70312501)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 人工内耳 / ステロイド溶出 / 残存聴力

Outline of Final Research Achievements

We analyzed gene expression patterns in the cochlea after insertion of a conventional electrode and a dexamethasone-eluting electrode into the guinea pig cochlea to examine the effects of continuous steroid administration. After insertion of a conventional electrode into the cochlea, damage to the cochlear structure and neurotransmission disorders such as hair cells occurred due to the electrode insertion, resulting in changes in the expression of various genes such as inflammatory cytokines. However, the use of dexamethasone-eluting electrodes suppressed the changes in gene expression, especially the expression of inflammatory cytokines such as TNF-α and IL-1β, which have the potential to damage nerve cells, and thus were thought to be effective in protecting hair cells in the cochlea.
Experiments to examine the functional and morphological effects of long-term electrode implantation in the cochlea using mice were discontinued.

Free Research Field

耳鼻咽喉科学

Academic Significance and Societal Importance of the Research Achievements

残存聴力活用型人工内耳では、人工内耳電極挿入後の残存聴力は良好に保存される例が多いが、中には長期的経過観察で徐々に失われるケースもみられる。
ステロイド溶出電極を用いることで、炎症抑制のみならず蝸牛内線維化、基底板の振動障害、有毛細胞やラセン神経節細胞の活動障害が抑制できれば、人工内耳電極挿入後の長期の機能温存に有効であり、ひいては長期に残存聴力を維持して人工内耳を有効に使うことができる。