Ohgami Nobutaka, Li Xiang, Yajima Ichiro, Oshino Reina, Ohgami Kyoko, Kato Yoko, Ahsan Nazmul, Akhand Anwarul Azim, Kato Masashi
a Department of Occupational and Environmental Health , Nagoya University Graduate School of Medicine , Nagoya , Japan.
b Voluntary Body for International Health Care in Universities , Nagoya , Japan.
Biomarkers. 2018 Sep;23(6):533-539. doi: 10.1080/1354750X.2018.1458153. Epub 2018 Apr 10.
Elevated hearing thresholds from high frequencies are known to be one of the hallmarks of age-related hearing loss. Our recent study showed accumulation of manganese (Mn) in inner ears resulting in acceleration of age-related hearing loss in mice orally exposed to Mn. However, there is no evidence showing an association between Mn in non-invasive biological samples and hearing loss in humans evaluated by pure tone audiometry (PTA). In this study, we evaluated Mn in non-invasive biological samples as a possible biomarker for hearing loss in humans.
We determined hearing levels by PTA and Mn levels in toenails, hair and urine with an inductively coupled plasma mass spectrometer (ICP-MS) in 145 healthy subjects in Bangladesh.
Multivariable analyses showed that Mn levels in toenails, but not in hair and urine samples, were significantly associated with hearing loss at 8 kHz and 12 kHz. Moreover, our experimental study showed a significant correlation between Mn levels in inner ears and nails, but not hair, in mice orally exposed to Mn.
The results provide novel evidence that Mn in toenails is a possible biomarker for hearing loss at high frequencies in humans.
高频听力阈值升高是年龄相关性听力损失的标志之一。我们最近的研究表明，口服锰（Mn）的小鼠内耳中锰会蓄积，导致年龄相关性听力损失加速。然而，尚无证据表明非侵入性生物样本中的锰与通过纯音听力测定（PTA）评估的人类听力损失之间存在关联。在本研究中，我们评估了非侵入性生物样本中的锰作为人类听力损失可能生物标志物的情况。
我们用感应耦合等离子体质谱仪（ICP-MS）测定了孟加拉国145名健康受试者的PTA听力水平以及趾甲、头发和尿液中的锰含量。
多变量分析表明，趾甲中的锰含量与8kHz和12kHz的听力损失显著相关，而头发和尿液样本中的锰含量则不然。此外，我们的实验研究表明，口服锰的小鼠内耳中的锰含量与趾甲中的锰含量显著相关，与头发中的锰含量无关。
结果提供了新的证据，表明趾甲中的锰可能是人类高频听力损失的生物标志物。
