Hepsin-Induced Hearing Restorability and Schizophrenia

After hearing Dr. Wei-Meng Yu’s speech on hepsin, a protein that plays a huge role in normal auditory capabilities, I was tempted to continue researching neurological topics and disorders that could tie into the research results found by Dr. Yu and his colleagues. Dr. Yu and his colleagues discovered that injecting hepsin from humans restored some hearing in mice with a gene that knocked out hepsin activation causing hearing loss (Yu et al., 2024). They also discovered that injecting human hepsin into these partially deaf mice caused some reformation of the tectorial membrane, a structure in the ear that allows for hearing.  It made me wonder if the results found could be of any aid in auditory hallucinations and auditory prediction. In other words, I wonder if introduction of hepsin could help people with schizophrenia, given schizophrenics usually have some type of hearing loss. 

In the article published by Alice Saperstein, Shanique Meyler, and Alice Medalia, the frequency of hearing loss amongst schizophrenic patients was discussed. Through their research, it was determined that patients with schizophrenia had a higher hearing threshold compared to other research subjects of their same age and gender (Saperstein et al., 2022). A higher hearing threshold indicated that these schizophrenic patients needed a noise/sound to be higher in volume in order to be analyzed or at the very least detected. The average hearing threshold for those with schizophrenia was 17.48.3 dB while those with normal hearing had a lower threshold of 14.16.4dB (Saperstein et al., 2022). This difference in threshold allowed the researchers to label the hearing loss in schizophrenics as mild. 

Malformation of the tectorial membrane (TM) causes vibrations to not be converted into neural signals well enough and the loss of those signals causes hearing loss in general. Because the TM works with vibrations of sounds, it can directly be linked to the high hearing threshold that schizophrenic patients have. Based on the research results concluded by Dr. Yu and his colleagues, hepsin could help reform the tectorial membrane and help improve hearing loss. Therefore, if schizophrenic patients could have hepsin introduced into their system, it could potentially help reform the tectorial membrane. In this case, the vibrations would not have to be as loud for them to hear (due to their high hearing threshold) and they would be able to hear at a lower threshold. Doing so could help with the sound overstimulation in these patients' brains and potentially minimize the effect of auditory hallucinations because they wouldn’t need to hear loud things in order to actually hear. In a recent study, researcher Ghazavi and her colleagues determined that patients with schizophrenia were more sensitive to noises than others. Based on results, schizophrenics with auditory hallucinations were even more sensitive to higher noises than schizophrenics with no auditory hallucinations (Ghazavi et al., 2023). This emphasizes the idea that hepsin could potentially help schizophrenic patients with auditory hallucinations in minimizing the effect of their hallucinations. 

References

Ghazavi, Z., Davarinejad, O., Jasimi, F., Mohammadian, Y., & Sadeghi, K. (2023). Noise Sensitivity in patients with Schizophrenia. Noise and Health, 25(117). https://journals.lww.com/nohe/fulltext/2023/25170/noise_sensitivity_in_patients_with_schizophrenia.2.aspx

Saperstein, A., Meyler, S., & Medalia, A. (2022). Hearing Loss Among People with Schizophrenia: Implications for Clinical Practice. Psychiatry Online, 74(5). https://psychiatryonline.org/doi/full/10.1176/appi.ps.20220226

Yu, W.M., Yang, T.H., Hsu, Y.C., Yeh. P., Hung, C.J., Tsai, Y.F., Fang, M.C., Yen, A.C.C., Chen, L.F., Pan, J. Y., Wu, C.C., Liu, T.C., Chong, F.L., & Lin, S.W. (2024). Critical Role of Hepsin/TMPRSS1 in hearing and tectorial membrane morphogenesis: Insights from transgenic mouse models. Science Direct, 453. https://www.sciencedirect.com/science/article/abs/pii/S0378595524001874?via%3Dihub