Journal article
Cochlear implant material effects on inflammatory cell function and foreign body response
Hearing research, Vol.426, 108597
08/04/2022
DOI: 10.1016/j.heares.2022.108597
PMCID: PMC10875706
PMID: 35963812
Abstract
•Cochlear implant electrodes are comprised of platinum contacts in a PDMS casing•Components of cochlear implant biomaterials influence the cellular response•Cells are more likely to adhere to and proliferate on platinum surfaces relative to PDMS•Murine cochleae after cochlear implantation show prominent fibrosis around platinum electrode contacts
The objectives of this study were to assess the effects of cochlear implant (CI) biomaterials on the function of macrophages and fibroblasts, two key mediators of the foreign body response (FBR) and to determine how these materials influence fibrous tissue growth and new bone formation within the cochlea.
Macrophages and fibroblasts were cultured on polydimethylsiloxane (PDMS) and platinum substrates and human CI electrodes in vitro. Cell count, cell proliferation, cytokine production, and cell adhesion were measured. CI electrodes were implanted into murine cochleae for one week without electrical stimulation. Implanted cochleae were harvested for 3D X-ray microscopy with the CI left in-situ. The location of new bone growth within the scala tympani (ST) with reference to different portions of the implant (PDMS vs platinum) was quantified.
Cell counts of macrophages and fibroblasts were significantly higher on platinum substrates and platinum contacts of CI electrodes. Fibroblast proliferation was greater on platinum relative to PDMS, and cells grown on platinum formed more/larger focal adhesions. 3D x-ray microscopy showed neo-ossification in the peri-implant areas of the ST. Volumetric quantification of neo-ossification showed a trend toward greater bone formation adjacent to the platinum electrodes compared to areas opposite or away from the platinum electrode bearing surfaces.
Fibrotic reactions are biomaterial specific, as demonstrated by the differences in cell adhesion, proliferation, and fibrosis on platinum and PDMS. The inflammatory reaction to platinum contacts on CI electrodes likely contributes to fibrosis to a greater degree than PDMS, and platinum contacts may influence the deposition of new bone, as demonstrated in the in vivo data. This information can potentially be used to influence the design of future generations of neural prostheses.
Details
- Title: Subtitle
- Cochlear implant material effects on inflammatory cell function and foreign body response
- Creators
- Megan J. Jensen - Department of Otolaryngology—Head & Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USAAlexander D. Claussen - University of IowaTimon Higgins - Carver College of Medicine, Iowa City, IA, USARene Vielman-Quevedo - University of IowaBrian Mostaert - University of IowaLinjing Xu - University of IowaJonathon Kirk - Cochlear (Australia)Marlan R. Hansen - Department of Otolaryngology—Head & Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
- Resource Type
- Journal article
- Publication Details
- Hearing research, Vol.426, 108597
- DOI
- 10.1016/j.heares.2022.108597
- PMID
- 35963812
- PMCID
- PMC10875706
- NLM abbreviation
- Hear Res
- ISSN
- 0378-5955
- eISSN
- 1878-5891
- Publisher
- Elsevier B.V
- Grant note
- DOI: 10.13039/100000002, name: National Institutes of Health, award: R01 DC012578, R01 DC018488, T32 DC00040
- Language
- English
- Date published
- 08/04/2022
- Academic Unit
- Molecular Physiology and Biophysics; Neurosurgery; Otolaryngology
- Record Identifier
- 9984297614302771
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