Effects of low-level sarin and cyclosarin exposure on white matter integrity in Gulf War Veterans
Effects of low-level sarin and cyclosarin exposure on white matter integrity in Gulf War Veterans
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DOI：
10.1016/j.neuro.2015.04.005
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发表时间：
2015-05-01
期刊：
影响因子：
3.4
通讯作者：
Buckley, Shannon
中科院分区：
文献类型：
--
作者：
Chao, Linda L.;Zhang, Yu;Buckley, Shannon
背景：我们先前发现了海湾战争(GW)退伍军人灰质和白质体积减少的证据，这些退伍军人预测低水平暴露于沙林(GB)和环沙林(GF)。由于白质组织完整性的丧失与灰质和白质萎缩有关，本研究试图验证这样的假设，即预测GB/CF暴露的GW退伍军人有证据表明白质微结构完整性受损。方法：通过对59名GW退伍军人和59名匹配的未暴露GW退伍军人(平均年龄：48+/-7岁)的4T弥散张量图像(DTI)评估分数各向异性和方向性(即轴向和径向)弥散系数。DTI数据采用感兴趣区(ROI)分析，考虑了年龄、性别、总的脑灰质和白质体积、创伤暴露、创伤后应激障碍、当前的重度抑郁症和慢性多症状疾病状态。结果：在各向异性分数或径向弥散率方面，组间没有显著差异。然而，与匹配的、未接触GB/GF的退伍军人相比，GW退伍军人的轴向弥散系数在整个大脑中都有增加，包括颞干、放射冠、上下扣带、下额枕上束、内囊和外囊以及皮质浅层白质刀片。事后分析显示，在未暴露的退伍军人中，较高的各向异性分数和较低的径向扩散系数与较好的神经行为表现之间存在显著相关性。相反，只有内囊后肢轴向弥散系数的增加才与预测GB/CF暴露的GW退伍军人更好的精神运动功能有关。结论：在含有皮质脊髓纤维下降的脑区发现轴向弥散增加与更好的精神运动功能有关，并且在预测GB/CF暴露的退伍军人中没有明显的神经行为缺陷，提示我们观察到的GW退伍军人轴向弥散系数普遍增加的可能性可能反映了脑损伤后脑白质重组(即暴露于GB/GF)。由爱思唯尔公司出版。
Background: We previously found evidence of reduced gray and white matter volume in Gulf War (GW) veterans with predicted low-level exposure to sarin (GB) and cyclosarin (GF). Because loss of white matter tissue integrity has been linked to both gray and white matter atrophy, the current study sought to test the hypothesis that GW veterans with predicted GB/CF exposure have evidence of disrupted white matter microstructural integrity.Methods: Measures of fractional anisotropy and directional (i.e., axial and radial) diffusivity were assessed from the 4 T diffusion tensor images (DTI) of 59 GW veterans with predicted GB/CF exposure and 59 "matched" unexposed GW veterans (mean age: 48 +/- 7 years). The DTI data were analyzed using regions of interest (ROI) analyses that accounted for age, sex, total brain gray and white matter volume, trauma exposure, posttraumatic stress disorder, current major depression, and chronic multisymptom illness status.Results: There were no significant group differences in fractional anisotropy or radial diffusivity. However, there was increased axial diffusivity in GW veterans with predicted GB/GF exposure compared to matched, unexposed veterans throughout the brain, including the temporal stem, corona radiata, superior and inferior (hippocampal) cingulum, inferior and superior fronto-occipital fasciculus, internal and external capsule, and superficial cortical white matter blades. Post hoc analysis revealed significant correlations between higher fractional anisotropy and lower radial diffusivity with better neurobehavioral performance in unexposed GW veterans. In contrast, only increased axial diffusivity in posterior limb of the internal capsule was associated with better psychomotor function in GW veterans with predicted GB/CF exposure.Conclusions: The finding that increased axial diffusivity in a region of the brain that contains descending corticospinal fibers was associated with better psychomotor function and the lack of significant neurobehavioral deficits in veterans with predicted GB/CF exposure hint at the possibility that the widespread increases in axial diffusivity that we observed in GW veterans with predicted GB/GF exposure relative to unexposed controls may reflect white matter reorganization after brain injury (i.e., exposure to GB/GF). Published by Elsevier Inc.