Changes in brain iron concentration after exposure to high-altitude hypoxia measured by quantitative susceptibility mapping
Changes in brain iron concentration after exposure to high-altitude hypoxia measured by quantitative susceptibility mapping
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通过定量磁化率图测量暴露于高原缺氧后脑铁浓度的变化
DOI：
10.1016/j.neuroimage.2016.12.033
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发表时间：
2017-02-15
期刊：
影响因子：
5.7
通讯作者：
Chen, Zhong
中科院分区：
文献类型：
--
作者：
Chen, Lin;Cai, Congbo;Chen, Zhong
缺氧可诱发生理变化。本研究旨在探讨高原（HA）缺氧对脑铁浓度的影响。29名健康的海平面居民在青藏高原（4200米）适应高原环境约4周前后不久接受检测，并在一年后重新适应海平面环境后再次接受调查。用定量磁化率成像（QSM）对铁浓度进行定量，并将结果与横向弛豫率（R*(2)）测量值进行比较。磁化率的变化表明，在暴露于高原环境后，灰质区域，尤其是基底神经节（包括尾状核、壳核、苍白球和黑质）中的铁浓度显著增加。这种增加似乎与R*(2)值变化得出的结论一致。然而，与QSM不同的是，R*(2)值未能显示红核中铁含量的统计学差异。再次调查结果显示，在重新适应海平面环境一年后，大多数变化都恢复了。此外，还分析了大脑区域中铁浓度变化的半球和性别相关差异。结果显示右半球和女性出现变化的可能性更大。基于扩散张量成像（DTI）的进一步研究表明，在6个深部灰质核中，暴露于高原环境后，部分各向异性增加，平均扩散率降低，且仅在壳核中与铁浓度呈线性相关。总之，磁化率值可作为脑铁的定量标志物，本文报道的区域磁化率变化表明，高原缺氧可导致大多数深部灰质区域出现显著的铁沉积。此外，壳核中DTI指标与铁浓度的线性相关性表明铁蛋白与水扩散之间存在潜在关系。
Hypoxia can induce physiological changes. This study aims to explore effects of high-altitude (HA) hypoxia on cerebral iron concentration. Twenty-nine healthy sea-level participants were tested shortly before and after approximately 4-week adaptation to the HA environment at fQinghai-Tibet Plateau (4200 m), and were re-investigated after re-adaptation to the sea-level environment one year later. Iron concentration was quantified with quantitative susceptibility mapping (QSM), and the results were compared with transverse relaxation rate (R*(2)) measurements. The variations of magnetic susceptibility indicate that the iron concentration in gray matter regions, especially in basal ganglia, including caudate nucleus, putamen, globus pallidus and substantia nigra, increases significantly after HA exposure. This increase appears consistent with the conclusion from R*(2) value variations. However, unlike QSM, the R*(2) value fails to demonstrate the statistical difference of iron content in red nucleus. The re-investigation results show that most variations are recovered after sea-level re-adaptation for one year. Additionally, hemisphere- and gender-related differences in iron concentration changes were analyzed among cerebral regions. The results show greater possibilities in the right hemisphere and females. Further studies based on diffusion tensor imaging (DTI) suggest that the fractional anisotropy increases and the mean diffusivity decreases after HA exposure in six deep gray matter nuclei, with linear dependence on iron concentration only in putamen. In conclusion, the magnetic susceptibility value can serve as a quantitative marker of brain iron, and variations of regional susceptibility reported herein indicate that HA hypoxia can result in significant iron deposition in most deep gray matter regions. Additionally, the linear dependence of DTI metrics on iron concentration in putamen indicates a potential relationship between ferritin and water diffusion.