Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA.
Neurotoxicology. 2012 Oct;33(5):1298-304. doi: 10.1016/j.neuro.2012.08.002. Epub 2012 Aug 18.
Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson's disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson's disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson's disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson's disease patients. When stratified by sex, the female Parkinson's disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson's disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson's disease-related pathology. Furthermore, these data support epidemiological and laboratory studies reporting a link between PCB exposure and an increased risk for Parkinson's disease, including greater susceptibility of females.
多氯联苯 (PCBs) 是一种合成化学物质，主要用作电气设备的冷却剂和绝缘体。尽管已经禁用了几十年，但由于其半衰期长、禁令前生产的物品中仍存在 PCBs 以及处理不善，PCBs 仍继续存在于环境中。流行病学和实验研究已经确定，接触 PCBs 是帕金森病的一个潜在风险因素，女性中可能更为明显。这项工作的目的是研究死后人脑组织中 PCB 水平与帕金森病诊断以及黑质脱色素程度之间的关系。我们还试图确定，如果按性别对患者进行分层，这种关联是否更为显著。来自埃默里大学大脑银行和努恩研究的对照组患者和被诊断为帕金森病的患者死后脑组织样本被获取。从死后脑组织中提取并使用气相色谱-质谱法分析八种常见 PCB 同系物的浓度。在帕金森病患者的大脑中，同系物 153 和 180 的浓度明显升高。按性别分层时，与对照组相比，女性帕金森病组总 PCB 及其特定同系物 138、153 和 180 的浓度明显升高，而男性对照组和帕金森病组之间的 PCB 浓度没有显著差异。在另一组没有帕金森病临床症状或体征的女性（努恩研究）中，与轻度或无脱色素的受试者相比，中度黑质脱色素的死后脑组织中也观察到总 PCB 和同系物 138、153 和 180 的浓度升高。这些定量数据表明，脑 PCB 水平与帕金森病相关病理之间存在关联。此外，这些数据支持报告 PCB 暴露与帕金森病风险增加之间存在联系的流行病学和实验室研究，包括女性的易感性更高。
