早发性与迟发性阿尔茨海默病患者大脑葡萄糖代谢的差异

Differences in cerebral glucose metabolism between early-and late-onset of Alzheimer's disease

目的初步探讨早发性阿尔茨海默病(AD)与迟发性 AD 患者大脑葡萄糖代谢的差异。方法对9例早发性 AD、14例迟发性 AD 患者及分别与其年龄相匹配的29名年轻健康对照者和11名老年健康对照者进行^(18)F-氟脱氧葡萄糖(^(18)F-FDG)PET 脑显像。应用统计参数图对 PET 数据进行基于体素水平的图像分析。结果早发性 AD 组葡萄糖代谢相对于年轻对照组减低的脑区及其在Brodmann 分区图(BA)的定位分别为双侧额上回(BA6,8)、额中回(BA6),左侧顶下小叶(BA39),右侧缘上回(BA40)、扣带回(BA31)等部位(P<0.01);迟发性 AD 组葡萄糖代谢相对于老年对照组葡萄糖代谢减低的脑区及其定位分别为双侧额上回(BA8)、额中回(BA6,8)、楔前叶(BA19)、右侧角回(BA39)等部位(P<0.01)。结论尽管严重程度、病程及受教育水平相当,但是早发性 AD 患者大脑葡萄糖代谢减低的范围比迟发性 AD 更广泛,程度也更严重。不同发病年龄 AD 患者大脑葡萄糖代谢的差异可能是由于二者的认知储备能力不同所致。

Objective To investigate the differences in the cerebral glucose metabolism between early- and late-onset of Alzheimer＇ s disease（AD） , using a voxel-based method. Methods Nine early-onset and 14 late-onset AD patients were included in our study. Two groups of age-matched normal subjects were used as normal controls, ^18F-fluorodeoxyglucose （FDG） PET imaging was performed in all subjects to evaluate the relative cerebral glucose metabolic rate. Subsequently, PET data was statistically compared between the patients and the normal controls using statistical parametric mapping. Results As compared with the age-matched normal controls, respectively, significant hypometabolic regions were found bilaterally in the superior frontal gyrus （BA6,8） , middle frontal gyrus （BA6） , left inferior parietal lobule （BA39） , right supramarginal gyrus （BA40） and the posterior cingulate cortex （BA31） in early-onset AD patients （P 〈0. 01 ） and bilaterally in the superior frontal gyrus （BAS） , middle frontal gyrus （BA6,8） , precuneus （BA19） and right angular gyrus （BA39） in late-onset AD patients（ P 〈 0. 01 ）. Conclusions The early- onset patients are involved in wider areas with a severer degree of metabolic deterioration than the late-onset group as compared with the age-matched normal controls, respectively, though their dementia severity, duration of the illness and the level of education are all similar. The hypothesis of cognitive reserve capability may account for the differences in the cerebral glucose metabolism between the early-onset and the late-onset types of AD.