硫胺素缺乏与听力损失

Thiamine Deficiency and Hearing Loss

硫胺素即维生素B1,在机体中会被转化为辅酶参与能量、脂类及核酸代谢等生理过程。机体缺乏硫胺素可以导致韦尼克脑病(WE),其患者由于双侧对称的间脑和脑干损害,常常出现ABR的波间期延长并时有听力下降的症状。SLC19A2基因变异会导致硫胺响应性巨幼细胞贫血综合征(TRMA),其患者由于缺乏该基因编码的硫胺转运体THTR-1,使得内耳组织无法转运硫氨素,造成源于内耳的逐渐加重的感音神经性听力损失。由于听力下降不是WE中最典型的症状,TRMA也是不常见的遗传疾病,使得听力学研究者们对它们不甚熟悉,但其实两者的听力损失恰好是由于听觉通路的不同环节对硫胺素的依赖程度不同而造成的。本文首次系统地将缺乏硫胺素所造成的听力损失串联起来。通过介绍其中听力损失的发生机制以及相关的研究模型,我们希望能将这些理论应用于听力学研究,帮助研究者们加深对中枢性听力损失的发病机制以及内耳不同组织间的相互作用的理解。

Thiamine, also known as vitamin B1, works as a crucial coenzyme facilitating energy production, and lipids and ribose metabolisms. Its deficiency can cause a range of diseases including Wernicke encephalopathy （WE）, which is caused by selective and symmetrical damage of the diencephalon and brain stem. Patients with WE usually have prolonged in- ter-peak latencies on ABR tests, and occasionally suffer from evident hearing loss. On the other hand, mutations of gene SLC 192A can deprive patients of the high affinity thiamine transporter, THTR-1, and cause thiamine-responsive megaloblas- tic anemia （TRMA）. Due to the insufficient thiamine transported into inner ear tissues, patients with TRMA will suffer from a progressive sensorineural hearing loss. Because WE does not guarantee a symptom of hearing loss, and TRMA is also a rela- tively rare genetic disease, they are not very familiar to audiology researchers. But in fact, these two diseases are caused by different responses to thiamine deficiency by different tissues in the auditory pathway. In this paper, for the first time, we sys- tematically reviewed thiamine related hearing loss. By describing mechanisms and relevant animal models of these two diseas- es, we hope the proposed theories can be applied to auditory studies and help researchers better understand the pathology of central hearing loss and interactions among different tissues of the inner ear.