PDF(Pubmed)
Abstract：
Vascular risk factors contribute to cognitive aging, with one such risk factor being dysfunction of the blood brain barrier (BBB). Studies using non-invasive magnetic resonance imaging (MRI) techniques, such as diffusion prepared arterial spin labeling (DP-ASL), can estimate BBB function by measuring water exchange rate (kw). DP-ASL kw has been associated with cognition, but the directionality and strength of the relationship is still under investigation. An additional variable that measures water in extracellular space and impacts cognition, MRI free water (FW), may help explain prior findings. A total of 94 older adults without dementia (Mean age = 74.17 years, 59.6% female) underwent MRI (DP-ASL, diffusion weighted imaging (DWI)) and cognitive assessment. Mean kw was computed across the whole brain (WB), and mean white matter FW was computed across all white matter. The relationship between kw and three cognitive domains (executive function, processing speed, memory) was tested using multiple linear regression. FW was tested as a mediator of the kw-cognitive relationship using the PROCESS macro. A positive association was found between WB kw and executive function [F(4,85) = 7.81, p < .001, R2= 0.269; β = .245, p = .014]. Further, this effect was qualified by subsequent results showing that FW was a mediator of the WB kw-executive function relationship (indirect effect results: standardized effect = .060, bootstrap confidence interval = .0006 to .1411). Results suggest that lower water exchange rate (kw) may contribute to greater total white matter (WM) FW which, in turn, may disrupt executive function. Taken together, proper fluid clearance at the BBB contributes to higher-order cognitive abilities.
摘要：
血管危险因素有助于认知老化，其中一个危险因素是血脑屏障（BBB）功能障碍。使用非侵入性磁共振成像（MRI）技术的研究，如扩散制备动脉自旋标记(DP-ASL)，可以通过测量水交换率(kw)来估计BBB函数。DP-ASLkw与认知相关，但是这种关系的方向性和强度仍在调查中。测量细胞外空间中的水并影响认知的另一个变量，MRI自由水（FW），可能有助于解释先前的发现。共有94名没有痴呆的老年人(平均年龄=74.17岁，59.6％女性）接受了MRI（DP-ASL，弥散加权成像（DWI））和认知评估。计算整个大脑的平均千瓦数(WB)，计算所有白质的平均白质FW。kw与三个认知域(执行功能，处理速度,记忆)使用多元线性回归进行测试。使用过程宏测试了FW作为kw-认知关系的中介。发现WBkw与执行功能之间存在正相关[F（4,85）=7.81，p<.001，R2=0.269；β=.245，p=.014]。Further,该效应被随后的结果显示FW是WBkw-执行功能关系的中介(间接效应结果:标准化效应=.060,bootstrap置信区间=.0006至.1411)所证实.结果表明，较低的水交换率（kw）可能有助于增加总白质（WM）FW，反过来,可能会扰乱执行功能。一起来看,BBB处适当的液体清除有助于更高阶的认知能力。
