锰和铁暴露与弛豫率 R1 和 R2*的关联：来自 WELDOX II 研究的磁共振成像结果。
Association of exposure to manganese and iron with relaxation rates R1 and R2*- magnetic resonance imaging results from the WELDOX II study.
机构信息
Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bochum, Germany.
School of Health Sciences, Purdue University, West Lafayette, IN, USA; Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
出版信息
Neurotoxicology. 2018 Jan;64:68-77. doi: 10.1016/j.neuro.2017.08.008. Epub 2017 Aug 25.
OBJECTIVE
Magnetic resonance imaging is a non-invasive method that allows the indirect quantification of manganese (Mn) and iron (Fe) accumulation in the brain due to their paramagnetic features. The WELDOX II study aimed to explore the influence of airborne and systemic exposure to Mn and Fe on the brain deposition using the relaxation rates R1 and R2* as biomarkers of metal accumulation in regions of interest in 161 men, including active and former welders.
MATERIAL AND METHODS
We obtained data on the relaxation rates R1 and R2* in regions that included structures within the globus pallidus (GP), substantia nigra (SN), and white matter of the frontal lobe (FL) of both hemispheres, as well as Mn in whole blood (MnB), and serum ferritin (SF). The study subjects, all male, included 48 active and 20 former welders, 41 patients with Parkinson's disease (PD), 13 patients with hemochromatosis (HC), and 39 controls. Respirable Mn and Fe were measured during a working shift for welders. Mixed regression models were applied to estimate the effects of MnB and SF on R1 and R2*. Furthermore, we estimated the influence of airborne Mn and Fe on the relaxation rates in active welders.
RESULTS
MnB and SF were significant predictors of R1 but not of R2* in the GP, and were marginally associated with R1 in the SN (SF) and FL (MnB). Being a welder or suffering from PD or HC elicited no additional group effect on R1 or R2* beyond the effects of MnB and SF. In active welders, shift concentrations of respirable Mn>100μg/m were associated with stronger R1 signals in the GP. In addition to the effects of MnB and SF, the welding technique had no further influence on R1.
CONCLUSIONS
MnB and SF were significant predictors of R1 but not of R2*, indicative of metal accumulation, especially in the GP. Also, high airborne Mn concentration was associated with higher R1 signals in this brain region. The negative results obtained for being a welder or for the techniques with higher exposure to ultrafine particles when the blood-borne concentration was included into the models indicate that airborne exposure to Mn may act mainly through MnB.
目的
磁共振成像是一种非侵入性方法，可通过其顺磁特性间接定量测量脑内锰（Mn）和铁（Fe）的积累。WELDOX II 研究旨在通过弛豫率 R1 和 R2*探索空气中和全身暴露于 Mn 和 Fe 对 161 名男性（包括现役和前焊工）脑内金属积累的影响，这些男性的大脑中包含感兴趣区域的结构，这些结构包括苍白球（GP）、黑质（SN）和额叶白质（FL）。
材料和方法
我们获得了包括大脑中苍白球（GP）、黑质（SN）和额叶白质（FL）在内的结构的 R1 和 R2弛豫率数据，以及全血 Mn（MnB）和血清铁蛋白（SF）数据。研究对象均为男性，包括 48 名现役和 20 名前焊工、41 名帕金森病（PD）患者、13 名血色病（HC）患者和 39 名对照。在焊工的轮班期间测量可呼吸的 Mn 和 Fe。混合回归模型用于估计 MnB 和 SF 对 R1 和 R2的影响。此外，我们还估计了空气中 Mn 和 Fe 对现役焊工弛豫率的影响。
结果
MnB 和 SF 是 GP 中 R1 的显著预测因子，但不是 R2的预测因子，在 SN（SF）和 FL（MnB）中与 R1 呈边缘相关。作为焊工、患有 PD 或 HC，除了 MnB 和 SF 的影响外，不会对 R1 或 R2产生额外的组间效应。在现役焊工中，可呼吸 Mn 浓度>100μg/m 与 GP 中 R1 信号增强有关。除了 MnB 和 SF 的影响外，焊接技术对 R1 没有进一步的影响。
结论
MnB 和 SF 是 R1 的显著预测因子，但不是 R2*的预测因子，表明金属积累，尤其是在 GP 中。此外，空气中 Mn 浓度升高与该脑区 R1 信号升高有关。当将血液中 Mn 浓度纳入模型时，焊工或接触超细颗粒的技术暴露较高的情况下，得到的阴性结果表明，空气中 Mn 暴露可能主要通过 MnB 起作用。
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