Myelin breakdown mediates age-related slowing in cognitive processing speed in healthy elderly men
Myelin breakdown mediates age-related slowing in cognitive processing speed in healthy elderly men
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DOI：
10.1016/j.bandc.2012.09.006
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发表时间：
2013-02-01
影响因子：
2.5
通讯作者：
Bartzokis, George
中科院分区：
文献类型：
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作者：
Lu, Po H.;Lee, Grace J.;Bartzokis, George
背景：为了评估一种假设，即在一个非常健康的老年男性样本中，被选为最大限度地减少阿尔茨海默病(AD)和脑血管疾病的风险，晚期髓鞘区域的髓鞘破坏介导了与年龄相关的认知处理速度(CPS)的减慢。材料和方法：额叶前叶白质和膝盖骨在大脑发育的后期(晚期髓鞘白质；LMWM)更容易由于正常衰老的影响而崩溃。38例健康老年男性(平均年龄66.3岁；SD=6.0；范围55-76)获得了LMWM髓鞘完整性(横向松弛率；R-2)的体内MRI生物标志物。为了评估区域特异性，我们还评估了一个对比鲜明的早期髓鞘区域(胼胝体压部；SWM)，该区域主要包含参与视觉处理的轴突。结果：LMWM R-2与CPS测量值显著相关(r=.515，p=.0009)，而压部的R-2与CPS无显著相关性(p=.409)。LMWM R-2，而不是SWM R-2，是年龄和CPS之间关系的显著中介因素(p=.037)。结论：在这个非常健康的老年样本中，CPS的年龄相关性减慢是由高度脆弱的晚髓鞘区域的髓鞘破坏介导的，而不是在压部。(C)2012 Elsevier Inc.保留所有权利。
Background: To assess the hypothesis that in a sample of very healthy elderly men selected to minimize risk for Alzheimer's disease (AD) and cerebrovascular disease, myelin breakdown in late-myelinating regions mediates age-related slowing in cognitive processing speed (CPS).Materials and methods: The prefrontal lobe white matter and the genu of the corpus callosum myelinate later in brain development (late-myelinating white matter; LMWM) and are more vulnerable to breakdown due to the effects of normal aging. An in vivo MRI biomarker of myelin integrity (transverse relaxation rates; R-2) of LMWM was obtained for 38 very healthy elderly adult men (mean age = 66.3 years; SD = 6.0; range = 55-76). To evaluate regional specificity, we also assessed a contrasting early-myelinating region (splenium of the corpus callosum; SWM), which primarily contains axons involved in visual processing. CPS was assessed using the Trail Making Test.Results: LMWM R-2 and CPS measures were significantly correlated (r = .515, p = .0009), but no significant association between R-2 and CPS was detected in the splenium (p = .409). LMWM R-2, but not SWM R-2, was a significant mediator of the relationship between age and CPS (p = .037).Conclusions: In this very healthy elderly sample, age-related slowing in CPS is mediated by myelin breakdown in highly vulnerable late-myelinating regions but not in the splenium. (C) 2012 Elsevier Inc. All rights reserved.