AD患者脉压差增加预示脑血管病风险增加
2012-04-12 14:08:07   来源： 丁香园   作者：  评论：0 点击：

加利福尼亚大学圣地亚哥分校和圣地亚哥老龄健康体系的研究人员发现，脉压差增加可能升高患有阿尔海默茨病老年人的脑血管疾病（CVD）风险。该研究已被刊表于《Journal ofAlzheimer's Disease》在线版，并将于6月5日影印出版。

这样的发现或许可对AD治疗方面产生影响，因为一些抗高血压药物特定地作用于血压的搏动成分。脉压（PP）与收缩压和舒张压不同，它是血压的搏动成分。而PP大多随着年龄增加而增大，部分可归因于动脉硬化。

高 血压是AD的常见危险因素，但是利用抗高血压药物来预防痴呆产生杂乱的效果。以往大部分探究血压对AD风险的影响的研究都将注意力集中于血压的标志度量和 收缩压和舒张压数值上。然而，现在科学家们提出这样的理论：脉压差增加可能削弱从大脑中清除AD的标志物——β-淀粉样蛋白的能力。其他的研究也表明，脉 压差增加可能通过直接增加CVD风险而促使AD风险增加。

圣地亚哥老龄健康体系和加利福尼亚大学圣地亚哥分校精神科Mark W.Bondi博士领导的研究团队研究了65名晚期符合AD活检标准的患者，这些患者在死前都接受有关血压和神经病理标志物关系的一些检查。在活检中发现，有超过半数的患者患有CVD。

Bondi说，“PP和CVD的关联并不依赖于痴呆的严重程度和其他血管危险因素的出现。有趣的是，血压的标准度量与CVD的出现也无显著的联系。”

该项研究可得到如下结论：第一，年老的AD患者血压升高与CVD有关，而与AD的病理无关；第二，CVD与PP的关联比与收缩压或舒张压的关联更为密切；第三，AD患者PP增加或可通过影响CVD从而对认知功能产生影响。

该研究第一作者，圣地亚哥老龄健康体系Daniel A.Nation博士总结说，这些发现为可能的治疗方法提供些暗示。“以血压搏动成分为抗高血压治疗的靶向目标或许可减少AD患者血管对认知功能的损害，或减少个体患AD的风险。”

In Alzheimer's Patients, Pulse Pressure Elevation Could Presage Cerebrovascular Disease
Researchers at the University of California, San Diego and Veterans Affairs San Diego Healthcare System have shown that elevated pulse pressure may increase the risk of cerebrovascular disease (CVD) in older adults with Alzheimer's disease (AD). Their study has been published in the early online edition of Journal of Alzheimer's Disease in advance of the June 5 print publication.

The findings may have treatment implications, since some antihypertensive medications specifically address the pulsatile component of blood pressure. Pulse pressure (PP) - the difference between systolic and diastolic pressure - is one measure of the pulsatile component of blood pressure. PP increases substantially with age, partially due to hardening of the arteries.

Hypertension is a common risk factor for AD, but the use of antihypertensive medications to prevent dementia has had mixed results. Most studies examining the effects of blood pressure on the risk of AD have focused on standard measures of blood pressure, the systole and diastole readings. However, scientists theorized that PP elevation may impair the clearance of beta amyloid - a hallmark of AD - from the brain. Other studies have suggested that PP elevation may contribute to AD risk indirectly by increasing the risk of CVD.

The researchers, led by Mark W. Bondi, PhD, of VA San Diego Healthcare System and UC San Diego Department of Psychiatry, looked at 65 patients who later met the criteria for AD at autopsy. These patients were examined before death for relationships among blood pressure and neuropathologic markers. More than half of them were found, at autopsy, to have CVD.

"The association between PP and CVD was independent of dementia severity and the presence of other vascular risk factors," said Bondi. "Interestingly, standard measures of blood pressure were not significantly associated with the presence of CVD."

The study suggests several conclusions: that elevated blood pressure in older adults with AD is related to CVD but not AD pathology; that CVD may be more closely associated with PP than systolic or diastolic pressure; and that, in AD patients, PP elevation may be influencing cognition through effects on CVD.

The study's first author, Daniel A. Nation, PhD, of the VA San Diego Healthcare System, concluded the findings offer possible treatment implications. "Antihypertensive treatments targeting the pulsatile component of blood pressure may reduce the vascular contribution to cognitive impairment in AD patients or in individuals at risk of AD."