Supporting cell responses to cochlear damage

We investigated how supporting cells in the cochlea respond to damage caused by cyclodextrin, a compound that selectively harms outer hair cells. While sensory cell loss was extensive, especially in the basal and middle cochlear regions, many supporting cells—particularly in the apical region—survived. Among supporting cells, Deiters’ cells were generally more resilient than pillar cells, though their susceptibility varied by row and location. Hensen’s cells were found to participate in structural repair by forming a new epithelial layer after collapse of the organ of Corti. Overall, the findings highlight region- and cell-type-specific vulnerabilities and reveal supporting cells’ contributions to epithelial restoration after cochlear injury.
https://doi.org/10.1016/j.heares.2025.109201

Sex plays an important role in how tissues function and how diseases develop. In the auditory system, males and females show differences in how the cochlea works and responds to damage, but the reasons for these differences are not fully understood. Using RNA sequencing, we found many genes with sex-biased expression. While some of these are on sex chromosomes, most are on autosomes. In males, the biased genes are linked to energy production and gene regulation. In females, they are related to sound signal processing and nerve communication. These findings highlight key molecular differences between sexes and suggest directions for future research on how these differences affect hearing and disease.
https://doi.org/10.1016/j.heares.2024.109030

Macrophages in the Organ of Corti

Macrophages are the main immune cells in the cochlea, but their role in the organ of Corti is not well understood. Using an ototoxicity model of cochlear damage, we found that acute cochlear damage brings macrophages into the cochlea. At first, these cells stay outside the organ of Corti, but over time they move in and show an unique pattern of activation. Their presence is linked more to damage in supporting cells than to outer hair cell loss. A similar pattern of macrophage activities in the organ of Corti was seen in aging ears. These results suggest that macrophages in the organ of Corti are involved in supporting cell damage and repair, offering potential targets for treatment after cochlear injury.
https://doi.org/10.3389/fimmu.2025.1617146