Hearing loss is a serious public health issue. Nearly one-third of all 64-year-old adults have significant age-related hearing loss and that number almost doubles to 64% after the age of 85. In relation, noise-induced hearing loss is one of the most common self-reported occupational injuries.
Researchers from Harvard Medical School have investigated age-related hearing loss and noise-induced hearing loss, which are the two most common types of hearing loss. Through their research, they have gained insight into the protective mechanisms of hearing loss.
The researchers investigated whether over expression of the ISL1-gene in the inner ear of mice could be effective in protecting the inner ear. The results showed that the gene protects the hair cells of the inner ear from degeneration during ageing and that it promotes hair cell survival after exposure to loud noises. This means that the hearing of the ageing mice or in the mice exposed to intense noise was significantly better than in mice without the expressed gene.
With the findings of the study, researchers hope to extend the results to humans and thus in the future to protect human hearing from age-related hearing loss and noise-induced hearing loss.
In the study of the ISL1-gene, the researchers also discovered that the gene preserved the connections between the hair cells and the neurons in the inner ear.
Such a connection is necessary for hearing and it is the preservation of these connections that promotes hair cell survival, which may then minimize the hearing impairment that normally occurs with ageing and/or overexposure to noise.
About the study
The study was carried out by Dr. Zheng-Yi Chen, Dr. Mingqian Huang and a group of researchers from Massachusetts Eye and Ear and Harvard Medical School. The research and its results were published in the “Journal of Neuroscience”.