Cambridge Hearing Group, Cambridge, CB2 8AF, UK.
Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK.
Adv Healthc Mater. 2023 Sep;12(24):e2300732. doi: 10.1002/adhm.202300732. Epub 2023 Jun 22.
Cochlear implants are a life-changing technology for those with severe sensorineural hearing loss, partially restoring hearing through direct electrical stimulation of the auditory nerve. However, they are known to elicit an immune response resulting in fibrotic tissue formation in the cochlea that is linked to residual hearing loss and suboptimal outcomes. Intracochlear fibrosis is difficult to track without postmortem histology, and no specific electrical marker for fibrosis exists. In this study, a tissue-engineered model of cochlear fibrosis is developed following implant placement to examine the electrical characteristics associated with fibrotic tissue formation around electrodes. The model is characterized using electrochemical impedance spectroscopy and an increase in the resistance and a decrease in capacitance of the tissue using a representative circuit are found. This result informs a new marker of fibrosis progression over time that is extractable from voltage waveform responses, which can be directly measured in cochlear implant patients. This marker is tested in a small sample size of recently implanted cochlear implant patients, showing a significant increase over two postoperative timepoints. Using this system, complex impedance is demonstrated as a marker of fibrosis progression that is directly measurable from cochlear implants to enable real-time tracking of fibrosis formation in patients, creating opportunities for earlier treatment intervention to improve cochlear implant efficacy.
人工耳蜗是一种改变生活的技术，适用于患有严重感觉神经性听力损失的人，通过对听神经的直接电刺激来部分恢复听力。然而，众所周知，它们会引发免疫反应，导致耳蜗内纤维组织形成，从而导致残余听力损失和不理想的结果。如果没有死后组织学，耳蜗内纤维化很难跟踪，而且没有针对纤维化的特定电标记。在这项研究中，在植入后开发了一种耳蜗纤维化的组织工程模型，以研究与电极周围纤维组织形成相关的电特性。该模型使用电化学阻抗谱进行了表征，并发现组织的电阻增加，电容减小，使用代表性电路。这一结果提供了一个新的纤维化进展标志物，可以随着时间的推移从电压波形响应中提取出来，并可以直接在耳蜗植入患者中测量。该标志物在最近植入耳蜗植入患者的小样本量中进行了测试，在两个术后时间点显示出显著增加。使用该系统，复杂阻抗被证明是纤维化进展的标志物，可以从耳蜗植入物直接测量，从而实现对患者纤维化形成的实时跟踪，为早期治疗干预提供机会，以提高耳蜗植入物的疗效。
