脑白质完整性与衰老和痴呆的皮质代谢关联。
White matter integrity and cortical metabolic associations in aging and dementia.
机构信息
Helen Wills Neuroscience Institute, University of California at Berkeley, USA.
出版信息
Alzheimers Dement. 2010 Jan;6(1):54-62. doi: 10.1016/j.jalz.2009.04.1228.
BACKGROUND
Studies show that white matter hyperintensities, regardless of location, primarily affect frontal lobe metabolism and function. This report investigated how regional white matter integrity (measured as fractional anisotropy [FA]) relates to brain metabolism, to unravel the complex relationship between white matter changes and brain metabolism.
OBJECTIVE
To elucidate the relationship between white matter integrity and gray matter metabolism using diffusion tensor imaging and fluorodeoxyglucose-positron emission tomography in a cohort of 16 subjects ranging from normal to demented (age, >55 years).
METHODS
Mean FA values from white matter regions underlying the medial prefrontal, inferior-lateral prefrontal, parietal association, and posterior temporal areas and the corpus callosum were regressed with glucose metabolism (by positron emission tomography), using statistical parametric mapping (P < 0.005; voxel cluster, >100). Regional cerebral glucose metabolism was the primary outcome measure. According to our hypothesis, those hypometabolic cortical regions affected by Alzheimer's disease would correlate with a lower FA of associated tracks.
RESULTS
Our data show inter-regional positive correlations between FA and gray matter metabolism for the prefrontal cortex, temporal, and parietal regions. Our results suggest that left prefrontal FA is associated with left temporal and parietal metabolism. Further, left posterior temporal FA correlated with left prefrontal metabolism. Finally, bilateral parietal FA correlated with bilateral temporal metabolism.
CONCLUSIONS
These regions are associated with cognitive processes affected in Alzheimer's disease and cerebrovascular disease, suggesting a link with white matter degeneration and gray matter hypometabolism. Therefore, cortical function and white matter degeneration are related in aging and dementia.
背景
研究表明，无论白质高信号的位置如何，主要都影响额叶的代谢和功能。本研究旨在探讨区域白质完整性（以各向异性分数[FA]衡量）与脑代谢之间的关系，以揭示白质变化与脑代谢之间的复杂关系。
目的
使用扩散张量成像和氟脱氧葡萄糖正电子发射断层扫描技术，对 16 名年龄在 55 岁以上、从正常到痴呆的受试者队列进行研究，以阐明白质完整性与灰质代谢之间的关系。
方法
使用统计参数映射（P < 0.005；体素簇，> 100），对内侧前额叶、下外侧前额叶、顶叶联合区和颞叶后区以及胼胝体下的白质区域的平均 FA 值与葡萄糖代谢（通过正电子发射断层扫描）进行回归。以区域脑葡萄糖代谢为主要观察指标。根据我们的假设，那些受阿尔茨海默病影响的代谢低下的皮质区域与相关轨迹的 FA 值较低相关。
结果
我们的数据显示，前额叶皮质、颞叶和顶叶区域之间的 FA 与灰质代谢之间存在区域间的正相关。我们的结果表明，左侧前额叶的 FA 与左侧颞叶和顶叶的代谢相关。此外，左侧颞叶后区的 FA 与左侧前额叶的代谢相关。最后，双侧顶叶的 FA 与双侧颞叶的代谢相关。
结论
这些区域与阿尔茨海默病和脑血管病中受影响的认知过程相关，提示与白质退变和灰质代谢低下有关。因此，皮质功能和白质退变在衰老和痴呆中是相关的。
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