Sible Isabel J, Yew Belinda, Dutt Shubir, Li Yanrong, Blanken Anna E, Jang Jung Yun, Ho Jean K, Marshall Anisa J, Kapoor Arunima, Gaubert Aimée, Bangen Katherine J, Sturm Virginia E, Shao Xingfeng, Wang Danny J, Nation Daniel A
Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA.
Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
Neuroimage Rep. 2022 Mar;2(1). doi: 10.1016/j.ynirp.2022.100080. Epub 2022 Jan 18.
Blood pressure variability is an emerging risk factor for stroke, cognitive impairment, and dementia, possibly through links with cerebral hypoperfusion. Recent evidence suggests visit-to-visit (e.g., over months, years) blood pressure variability is related to cerebral perfusion decline in brain regions vulnerable to Alzheimer's disease. However, less is known about relationships between short-term (e.g., < 24 hours) blood pressure variability and regional cerebral perfusion, and whether these relationships may differ by age. We investigated short-term blood pressure variability and concurrent regional cerebral microvascular perfusion in a sample of community-dwelling older adults without history of dementia or stroke and healthy younger adults. Blood pressure was collected continuously during perfusion MRI. Cerebral blood flow was determined for several brain regions implicated in cerebrovascular dysfunction in Alzheimer's disease. Elevated systolic blood pressure variability was related to lower levels of concurrent cerebral perfusion in medial temporal regions: hippocampus (β = -.60 [95% CI -.90, -.30]; < .001), parahippocampal gyrus (β = -.57 [95% CI -.89, -.25]; = .001), entorhinal cortex (β = -.42 [95% CI -.73, -.12]; = .009), and perirhinal cortex (β = -.37 [95% CI -.72, -.03]; = .04), and not in other regions, and in older adults only. Findings suggest a possible age-related selective vulnerability of the medial temporal lobes to hypoperfusion in the context of short-term blood pressure fluctuations, independent of average blood pressure, white matter hyperintensities, and gray matter volume, which may underpin the increased risk for dementia associated with elevated BPV.
血压变异性是中风、认知障碍和痴呆的一个新出现的风险因素，可能是通过与脑灌注不足的联系。最近的证据表明，就诊间（如数月、数年）血压变异性与易患阿尔茨海默病的脑区脑灌注下降有关。然而，关于短期（如<24小时）血压变异性与局部脑灌注之间的关系，以及这些关系是否因年龄而异，人们了解较少。我们在一组无痴呆或中风病史的社区居住老年人和健康年轻成年人样本中，研究了短期血压变异性和同时期的局部脑微血管灌注情况。在灌注磁共振成像期间持续收集血压数据。测定了与阿尔茨海默病脑血管功能障碍相关的几个脑区的脑血流量。收缩压变异性升高与内侧颞叶区域同时期脑灌注水平降低有关：海马体（β = -0.60 [95%置信区间 -0.90, -0.30]；P < 0.001）、海马旁回（β = -0.57 [95%置信区间 -0.89, -0.25]；P = 0.001）、内嗅皮质（β = -0.42 [95%置信区间 -0.73, -0.12]；P = 0.009）和鼻周皮质（β = -0.37 [95%置信区间 -0.72, -0.03]；P = 0.04），而在其他区域则无此关联，且仅在老年人中存在。研究结果表明，在短期血压波动的情况下，内侧颞叶可能存在与年龄相关的对灌注不足的选择性易损性，这与平均血压、白质高信号和灰质体积无关，这可能是血压变异性升高与痴呆风险增加相关的基础。
