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Comparative Cochlear-Vestibular Aging Reveals Age-Aligned Mitochondrial Ultrastructural Burden, Mitophagy-Autophagy
Jingyi Xie1,2, Xujia Zhang1,2, Jinyi Tian1,2
1The Second Affiliated Hospital of Xi'an Jiaotong University, Department of Otorhinolaryngology-Head and Neck Surgery, Xi'an, China.
Aging Cell
|June 23, 2026
Summary
Mitochondrial damage and impaired quality control in the aging cochlea and vestibular system correlate with sensory decline and synaptic issues. This links cellular aging to hearing and balance loss.
Area of Science:
- Otolaryngology
- Gerontology
- Cellular Biology
Background:
- Age-related hearing loss and balance decline are common but their shared cellular basis is unclear.
- The link between mitochondrial health, synaptic function, and sensory decline in aging is not well-defined.
Purpose of the Study:
- To investigate age-related changes in cochlear and vestibular systems in mice.
- To determine if mitochondrial injury and quality control dysfunction correlate with synaptic vulnerability and sensory decline.
Main Methods:
- Used SAMP8 mice across different ages for cochlear and vestibular aging studies.
- Employed functional assays, microscopy, and gene expression analysis (qPCR) to assess hair cells, synapses, mitochondria, and mitophagy/autophagy genes.
- Derived molecular indices including a flux-burden signature and TFEB-lysosome module.
Main Results:
- Progressive increases in auditory brainstem response (ABR) thresholds and vestibular evoked potential (VsEP) abnormalities were observed with age.
- Hair cell numbers were mostly preserved, but regional cochlear and vestibular hair cell loss occurred with age.
- Increased pathological mitochondria and a 'flux-burden' molecular signature correlated with high-frequency hearing loss and synaptic changes.
Conclusions:
- Mitochondrial ultrastructural injury and impaired quality control are associated with age-related sensory decline in both hearing and balance systems.
- These cellular changes are linked to synaptic vulnerability and molecular remodeling, contributing to progressive sensory dysfunction.
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