Recent findings from a collaborative study led by researchers María Eugenia Gomez-Casati from the Institute of Pharmacology at the University of Buenos Aires-CONICET, Mauricio Martin from the Institute of Medical Research Mercedes, and Martín Ferreyra from the National University of Córdoba in Argentina have shed light on the connection between age-related hearing loss and reduced cholesterol levels within the inner ear.
Published in the open-access journal PLOS Biology on August 24th, the experiments conducted unveil a potential solution involving phytosterols supplements, which could play a pivotal role in addressing sensory dysfunction and hearing impairment in mice.
Age Related Hearing Loss and Cholesterol
The research primarily focused on the outer hair cells (OHCs) in the inner ear, which are responsible for amplifying sounds by adjusting their length. Over time, these cells lose their ability to respond to sound stimuli, resulting in age-related hearing loss. Cholesterol has been identified as a key factor in maintaining the stretch response of OHCs.
Given that cholesterol levels in the brain tend to decline with age, the researchers theorized that hearing loss might be correlated with cholesterol loss in OHCs.
To test this hypothesis, the study was conducted on mice.
The researchers discovered that the enzyme CYP46A1, responsible for breaking down and recycling cholesterol, was more prevalent in the inner ears of older mice, which correlated with reduced cholesterol levels. Further experiments confirmed a causal relationship by inducing hearing loss in young mice through excessive activation of CYP46A1.
Interestingly, when plant-based cholesterol-like compounds known as phytosterols were introduced, they were successful in compensating for the cholesterol loss, leading to improved OHC function.
Supplements to Combat Age-Related Hearing Loss?
The significance of this discovery lies in the potential application of phytosterols supplements to combat age-related hearing loss. These supplements are readily available over-the-counter and could offer a convenient strategy to address sensory dysfunction. However, further research is needed to validate the effectiveness of phytosterols in mitigating hearing loss in both older mice models and potentially in humans.
The researchers emphasized:
“Our findings are very promising because they provide the first proof-of-principle supporting phytosterols supplementation as a possible approach for prevention or treatment of hearing loss.”
The potential introduction of phytosterols supplementation as a strategy extends implications beyond laboratory findings, offering the promise to pave the way for future interventions that could enhance the lives of those facing age-related hearing challenges.
- Sodero AO, Castagna VC, Elorza SD, Gonzalez-Rodulfo SM, Paulazo MA, et al. (2023) Phytosterols reverse antiretroviral-induced hearing loss, with potential implications for cochlear aging. PLOS Biology 21(8): e3002257. https://doi.org/10.1371/journal.pbio.3002257
Source: PLOS Biology