Early Noise-Induced Hearing Loss Accelerates Presbycusis Altering Aging Processes in the Cochlea

Several studies identified hearing loss as a risk factor for aging-related processes, including neurodegenerative diseases, as dementia and age-related hearing loss (ARHL). Although the association between hearing impairment in midlife and ARHL has been widely documented by epidemiological and experimental studies, the molecular mechanisms underlying this association are not fully understood. In this study, we used an established animal model of ARHL (C57BL/6 mice) to evaluate if early noise-induced hearing loss (NIHL) could affect the onset or progression of age-related cochlear dysfunction. We found that hearing loss can exacerbate ARHL, damaging sensory-neural cochlear epithelium and causing synaptopathy. Moreover, we studied common pathological markers shared between hearing loss and ARHL, demonstrating that noise exposure can worsen/accelerate redox status imbalance [increase of reactive oxygen species (ROS) production, lipid peroxidation, and dysregulation of endogenous antioxidant response] and vascular dysfunction [increased expression of hypoxia-inducible factor-1alpha (HIF-1 alpha) and vascular endothelial growth factor C (VEGFC)] in the cochlea. Unveiling the molecular mechanisms underlying the link between hearing loss and aging processes could be valuable to identify effective therapeutic strategies to limit the effect of environmental risk factors on age-related diseases.

Automated summary

Several studies have found that hearing loss is a risk factor for aging-related processes, such as neurodegenerative diseases and age-related hearing loss (ARHL). However, the molecular mechanisms underlying this association are still not fully understood. In this study, using an animal model, researchers discovered that early noise-induced hearing loss (NIHL) can worsen age-related cochlear dysfunction and damage the cochlear epithelium and synapses. They also found that noise exposure can imbalance redox status and disrupt vascular function in the cochlea. Understanding the molecular mechanisms linking hearing loss and aging processes is important for developing effective therapeutic strategies to mitigate the effect of environmental risk factors on age-related diseases.