A review of the auditory-gut-brain axis

Amy S Graham; Benneth Ben-Azu; Marie-Ève Tremblay; Peter Torre 3rd; Marjanne Senekal; Barbara Laughton; Andre van der Kouwe; Marcin Jankiewicz; Mamadou Kaba; Martha J Holmes

doi:10.3389/fnins.2023.1183694

A review of the auditory-gut-brain axis

Front Neurosci. 2023 Aug 3:17:1183694. doi: 10.3389/fnins.2023.1183694. eCollection 2023.

Authors

Amy S Graham^{1

2}, Benneth Ben-Azu^{3

4}, Marie-Ève Tremblay^{3

5

6

7

8

9

10}, Peter Torre 3rd¹¹, Marjanne Senekal¹², Barbara Laughton¹³, Andre van der Kouwe^{14

15}, Marcin Jankiewicz^{1

2}, Mamadou Kaba¹⁶, Martha J Holmes^{1

2

17

18}

Affiliations

¹ Imaging Sciences, Neuroscience Institute, University of Cape Town, Cape Town, South Africa.
² Department of Human Biology, Division of Biomedical Engineering, University of Cape Town, Cape Town, South Africa.
³ Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
⁴ Department of Pharmacology, Faculty of Basic Medical Sciences, College of Health Sciences, Delta State University, Abraka, Delta State, Nigeria.
⁵ Département de Médecine Moléculaire, Université Laval, Québec City, QC, Canada.
⁶ Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Quebec City, QC, Canada.
⁷ Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada.
⁸ Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
⁹ Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada.
¹⁰ Institute for Aging and Lifelong Health, University of Victoria, Victoria, BC, Canada.
¹¹ School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, CA, United States.
¹² Department of Human Biology, Division of Physiological Sciences, University of Cape Town, Cape Town, South Africa.
¹³ Family Clinical Research Unit, Department of Pediatrics and Child Health, Stellenbosch University, Cape Town, South Africa.
¹⁴ Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States.
¹⁵ Department of Radiology, Harvard Medical School, Boston, MA, United States.
¹⁶ Department of Pathology, Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa.
¹⁷ Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
¹⁸ ImageTech, Simon Fraser University, Surrey, BC, Canada.

Abstract

Hearing loss places a substantial burden on medical resources across the world and impacts quality of life for those affected. Further, it can occur peripherally and/or centrally. With many possible causes of hearing loss, there is scope for investigating the underlying mechanisms involved. Various signaling pathways connecting gut microbes and the brain (the gut-brain axis) have been identified and well established in a variety of diseases and disorders. However, the role of these pathways in providing links to other parts of the body has not been explored in much depth. Therefore, the aim of this review is to explore potential underlying mechanisms that connect the auditory system to the gut-brain axis. Using select keywords in PubMed, and additional hand-searching in google scholar, relevant studies were identified. In this review we summarize the key players in the auditory-gut-brain axis under four subheadings: anatomical, extracellular, immune and dietary. Firstly, we identify important anatomical structures in the auditory-gut-brain axis, particularly highlighting a direct connection provided by the vagus nerve. Leading on from this we discuss several extracellular signaling pathways which might connect the ear, gut and brain. A link is established between inflammatory responses in the ear and gut microbiome-altering interventions, highlighting a contribution of the immune system. Finally, we discuss the contribution of diet to the auditory-gut-brain axis. Based on the reviewed literature, we propose numerous possible key players connecting the auditory system to the gut-brain axis. In the future, a more thorough investigation of these key players in animal models and human research may provide insight and assist in developing effective interventions for treating hearing loss.

Keywords: auditory system; gut-brain axis; hearing loss; microbiome; noise.

Publication types

Review