Is there a way to reverse the irreversible damage to our hearing?
Kalyssa Platt | March 26th, 2024
Hearing loss constitutes a global concern and is particularly prevalent in the United States, where 17% of the population experiences some form of irreversible hearing impairment. Much of this hearing loss can be attributed to the detriment of hair cells located in the inner part of the ear, made up of the cochlea and the utricle. The principal contributor to this kind of hearing loss is repeated exposure to loud noises, which causes these hair cells to be damaged too often for recovery. College students, in particular, are susceptible to hearing loss due to their excessive use of headphones during various activities such as walking or studying, as well as their attendance at concerts, bars, and sporting events, where the noise level is especially high.
How can we hear?
Hearing is controlled by mechanosensory hair cells, which are present on the utricle and cochlea of the inner ear, as described by Dr. Biswas. When sound waves reach the inner part of the ear to a structure called the cochlea, they induce waves in the fluid that result in the bending of these hair cells. This bending converts the vibrations to electrical signals, enabling us to hear. If these hair cells are permanently damaged, these functions necessary for hearing are compromised, leading to hearing loss. There is currently no method of regenerating the growth of these necessary hair cells and therefore, no natural way of restoring hearing loss.
What is the goal of Vanderbilt’s Taha Jan Lab?
The primary goal of the Taha Jan Lab is to restore hearing by regenerating the hair cells present on the utricle. The utricle, a component of the inner ear responsible for both hearing and balance dysfunction, is the focal point of their research. The lab works specifically on the utricle of mice, and their target is to regenerate the hair cells present on the organ. Their methodology includes first destroying the utricle hair cells of the mice in P-1 (one day after birth) by injecting a particular drug, and then, in the following days, inspecting whether the mice have any observable regeneration of these cells. In mice, utricle regeneration is confined to their first seven days after birth, meaning that the regeneration is primarily observed during their first week of life. It is noteworthy that these mice are genetically engineered for facilitating these scientific investigations and that there is no other mammalian body suitable to test this research.
Should new hair cells on the utricle be found subsequent to their destruction, the lab’s objective is then to investigate the underlying pathways or scientific questions contributing to this regeneration. This inquiry involves examining the regenerated utricle hair cells under a microscope and determining the distinctions between the cells that regenerated and those that did not. The identified pathway would likely be associated with compensatory regeneration, in which the cells divide to form already differentiated cells. Following the identification of an activated regenerative protein or pathway in these regenerated utricle hair cells, the lab may undertake further research on their findings.
Dr. Biswas is a current postdoctoral scholar in the Taha Jan lab who completed his undergraduate studies, master’s degree in Biochemistry, and PhD at the University of Calcutta. Over the course of his two years of post-graduation in India, he worked on a different project for two semesters, where he found out that “research could really be [his] future”. Dr. Biswas earned his PhD in neuroscience, in which he worked on the degeneration of neurons due to chewing tobacco. This focus on degeneration sparked his profound interest in regeneration, especially in his 4th year of PhD, and influenced his decision to join this lab.
When asked about the ultimate purpose of the research, Dr. Biswas states that it is about “helping people and making a difference”. If the team identifies evidence of a pathway conducive to hair cell regeneration, they would then need to persuade the scientific community of the efficacy and safety of their findings for humans. The research conducted in the Taha Jan Lab has the potential to substantially advance the restoration of hearing loss in the human population.
Works Cited
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How Does Loud Noise Cause Hearing Loss? | NCEH | CDC. 24 Nov. 2020,
https://www.cdc.gov/nceh/hearing_loss/how_does_loud_noise_cause_hearing_loss.html.
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