Graham Amy S, Ben-Azu Benneth, Tremblay Marie-Ève, Torre Peter, Senekal Marjanne, Laughton Barbara, van der Kouwe Andre, Jankiewicz Marcin, Kaba Mamadou, Holmes Martha J
Imaging Sciences, Neuroscience Institute, University of Cape Town, Cape Town, South Africa.
Department of Human Biology, Division of Biomedical Engineering, University of Cape Town, Cape Town, South Africa.
Front Neurosci. 2023 Aug 3;17:1183694. doi: 10.3389/fnins.2023.1183694. eCollection 2023.
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.
听力损失给全球医疗资源带来了沉重负担，并影响了受影响者的生活质量。此外，它可能发生在外周和/或中枢。由于听力损失有多种可能的原因，因此有必要研究其中涉及的潜在机制。连接肠道微生物与大脑的各种信号通路（肠-脑轴）已在多种疾病和病症中得到确认并被充分证实。然而，这些通路在与身体其他部位建立联系方面的作用尚未得到深入探索。因此，本综述的目的是探讨将听觉系统与肠-脑轴联系起来的潜在机制。通过在PubMed中使用选定的关键词，并在谷歌学术中进行额外的手工搜索，确定了相关研究。在本综述中，我们在四个小标题下总结了听觉-肠-脑轴中的关键因素：解剖学、细胞外、免疫和饮食。首先，我们确定了听觉-肠-脑轴中的重要解剖结构，特别强调了迷走神经提供的直接联系。在此基础上，我们讨论了几种可能连接耳朵、肠道和大脑的细胞外信号通路。在耳朵的炎症反应与改变肠道微生物群的干预措施之间建立了联系，突出了免疫系统的作用。最后，我们讨论了饮食对听觉-肠-脑轴的影响。基于所综述的文献，我们提出了许多可能将听觉系统与肠-脑轴联系起来的关键因素。未来，在动物模型和人体研究中对这些关键因素进行更深入的研究，可能会提供深入见解，并有助于开发治疗听力损失的有效干预措施。
