JAD：脉搏血压升高可能预示AD患者脑血管疾病

加州大学圣迭戈分校圣地亚哥医疗系统的研究人员已经证明脉压升高可能会增加老年阿尔茨海默氏病（AD）患者脑血管疾病（CVD）的风险。他们的研究结果已发表在《阿尔茨海默氏病杂志》上。

这一发现可能具有治疗意义，因为有些降压药物能专门降低脉压。血压具有波动性，收缩压(SBP)和舒张压(DBP)分别代表血压波动的两个极端值，收缩压与舒张压之差称为脉压（PP），它反映了一个心动周期中该波动幅度的大小。PP随着年龄的增长会大幅增加，部分原因是由于血管硬化。

高血压是AD一种常见的危险因素，但使用抗高血压药物预防老年痴呆症的结果很复杂。大多数研究血压对AD的风险都集中在测量血压、心脏收缩和舒张读数等。然而，科学家们推测PP的增高可能会影响β淀粉样蛋白（AD患者一个标志物）清除出大脑。其他研究表明PP的增高间接增加心血管疾病后也可能增加患AD的风险，。

弗吉尼亚州圣迭戈医疗系统和加州大学圣迭戈分校精神病学系的Mark W. Bondi博士领导的研究团队对65例AD患者进行了标准的尸检研究。研究人员对这些患者死亡前进行了血压和神经病理标记之间关系的相关研究。结果在尸检中发现其中一半以上的人有心血管疾病。

这项研究表明以下几个结论：老年AD患者血压升高是与心血管疾病相关的，而不与AD病理相关；老年AD患者心血管疾病更可能是PP问题，而不是收缩压或舒张压出现了问题；AD患者，PP升高可能通过影响CVD进而影响患者的认知。

这项研究的第一作者弗吉尼亚州圣迭戈医疗系统Daniel A. Nation博士下结论称：针对血压搏动成分的降压治疗可能会减少血管对AD患者的认知功能障碍的影响以及减少患AD的风险。（生物谷：Bioon）

doi:10.3233/JAD-2011-102103
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Posterior Cingulum White Matter Disruption and Its Associations with Verbal Memory and Stroke Risk in Mild Cognitive Impairment

Delano-Wood L, Stricker NH, Sorg SF, Nation DA, Jak AJ, Woods SP, Libon DJ, Delis DC, Frank LR, Bondi MW.

Abstract: Medial temporal lobe and temporoparietal brain regions are among the earliest neocortical sites to undergo pathophysiologic alterations in Alzheimer’s disease (AD), although the underlying white matter changes in these regions is less well known. We employed diffusion tensor imaging to evaluate early alterations in regional white matter integrity in participants diagnosed with mild cognitive impairment (MCI). The following regions of interests (ROIs) were examined: 1) anterior cingulum (AC); 2) posterior cingulum (PC); 3) genu of the corpus callosum; 4) splenium of the corpus callosum; and 5) as a control site for comparison, posterior limb of the internal capsule. Forty nondemented participants were divided into demographically-similar groups based on cognitive status (MCI: n=20; normal control: n=20), and fractional anisotropy (FA) estimates of each ROI were obtained. MCI participants showed greater posterior white matter (i.e., PC, splenium) but not anterior white matter (i.e., AC, genu) changes, after adjusting for age, stroke risk, and whole brain volume. FA differences of the posterior white matter were best accounted for by changes in radial but not axial diffusivity. PC FA was also significantly positively correlated with hippocampal volume as well as with performance on tests of verbal memory, whereas stroke risk was significantly correlated with genu FA and was unrelated to PC FA. When investigating subtypes of our MCI population, amnestic MCI participants showed lower PC white matter integrity relative to those with non-amnestic MCI. Findings implicate involvement of posterior microstructural white matter degeneration in the development of MCI-related cognitive changes and suggest that reduced FA of the PC may be a candidate neuroimaging marker of AD risk.