Heterogeneous age-related breakdown of white matter structural integrity: implications for cortical "disconnection" in aging and Alzheimer's diesase
Heterogeneous age-related breakdown of white matter structural integrity: implications for cortical "disconnection" in aging and Alzheimer's diesase
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DOI：
10.1016/j.neurobiolaging.2003.09.005
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发表时间：
2004-08-01
影响因子：
4.2
通讯作者：
Cummings, JL
中科院分区：
文献类型：
--
作者：
Bartzokis, G;Sultzer, D;Cummings, JL
人类和非人类灵长类动物的数据表明，髓鞘的结构完整性在正常衰老过程中恶化，特别是在髓鞘形成后期的联合区域，并可能导致广泛分布的神经网络的“断开”。磁共振成像（MRI）被用来评估这一过程的异质性及其对脑老化和阿尔茨海默病（AD）的影响，通过评估早期和晚期髓鞘形成区域的胼胝体，压部（见）和背侧（Gee），分别。计算的横向弛豫率（R-2），间接措施的白色物质的结构完整性的Gee和见，进行了检查。年龄和R2之间的关系在两个区域不同。一个二次（倒U型）函数，从31岁开始加速下降，最能代表Gee模式，而See下降是三倍小，渐进的，线性的。这些数据表明，与年龄相关的髓鞘分解的严重程度在区域上是不均匀的，这与髓鞘性质的差异使髓鞘形成后期区域更容易受到该过程影响的假设一致。在AD中，这一过程全面加剧，与细胞外有害过程如淀粉样蛋白β-肽毒性一致。非侵入性的措施，如R2可能是有用的一级预防研究的AD。(C)2003年爱思唯尔公司All rights reserved.
Human and non-human primate data suggest that the structural integrity of myelin sheaths deteriorates during normal aging, especially in the late-myelinating association regions and may result in "disconnection" of widely distributed neural networks. Magnetic resonance imaging (MRI) was used to assess the heterogeneity of this process and its impact on brain aging and Alzheimer's disease (AD) by evaluating early- and later-myelinating regions of the corpus callosum, the splenium (See) and genu (Gee), respectively. Calculated transverse relaxation rates (R-2), an indirect measure of white matter structural integrity for the Gee and See, were examined. The relationship between age and R2 differed in the two regions. A quadratic (inverted U) function with an accelerating rate of decline beginning at age 31 best represented the Gee pattern while the See decline was three-fold smaller, gradual, and linear. These data suggest that the severity of age-related myelin breakdown is regionally heterogeneous, consistent with the hypothesis that differences in myelin properties make later-myelinating regions more susceptible to this process. In AD this process is globally exacerbated, consistent with an extracellular deleterious process such as amyloid beta-peptide toxicity. Non-invasive measures such as R2 may be useful in primary prevention studies of AD. (C) 2003 Elsevier Inc. All rights reserved.