BACKGROUND Mechanisms underlying the association between age-related arterial stiffening and poor brain health remain elusive. Cerebral blood flow (CBF) homeostasis may be implicated. This study evaluates how aortic stiffening relates to resting CBF and cerebrovascular reactivity (CVR) in older adults. METHODS Vanderbilt Memory & Aging Project participants free of clinical dementia, stroke, and heart failure were studied, including older adults with normal cognition (n=155; age, 72±7 years; 59% male) or mild cognitive impairment (n=115; age, 73±7 years; 57% male). Aortic pulse wave velocity (PWV; meters per second) was quantified from cardiac magnetic resonance. Resting CBF (milliliters per 100 g per minute) and CVR (CBF response to hypercapnic normoxia stimulus) were quantified from pseudocontinuous arterial spin labeling magnetic resonance imaging. Linear regression models related aortic PWV to regional CBF, adjusting for age, race/ethnicity, education, Framingham Stroke Risk Profile (diabetes mellitus, smoking, left ventricular hypertrophy, prevalent cardiovascular disease, atrial fibrillation), hypertension, body mass index, apolipoprotein E4 ( APOE ε4) status, and regional tissue volume. Models were repeated testing PWV× APOE ε4 interactions. Sensitivity analyses excluded participants with prevalent cardiovascular disease and atrial fibrillation. RESULTS Among participants with normal cognition, higher aortic PWV related to lower frontal lobe CBF (β=-0.43; P=0.04) and higher CVR in the whole brain (β=0.11; P=0.02), frontal lobes (β=0.12; P<0.05), temporal lobes (β=0.11; P=0.02), and occipital lobes (β=0.14; P=0.01). Among APOE ε4 carriers with normal cognition, findings were more pronounced with higher PWV relating to lower whole-brain CBF (β=-1.16; P=0.047), lower temporal lobe CBF (β=-1.81; P=0.004), and higher temporal lobe CVR (β=0.26; P=0.08), although the last result did not meet the a priori significance threshold. Results were similar in sensitivity models. Among participants with mild cognitive impairment, higher aortic PWV related to lower CBF in the occipital lobe (β=-0.70; P=0.02), but this finding was attenuated when participants with prevalent cardiovascular disease and atrial fibrillation were excluded. Among APOE ε4 carriers with mild cognitive impairment, findings were more pronounced with higher PWV relating to lower temporal lobe CBF (β=-1.20; P=0.02). CONCLUSIONS Greater aortic stiffening relates to lower regional CBF and higher CVR in cognitively normal older adults, especially among individuals with increased genetic predisposition for Alzheimer's disease. Central arterial stiffening may contribute to reductions in regional CBF despite preserved cerebrovascular reserve capacity.

中文翻译：

---

较高的主动脉僵硬度与较低的成年人大脑血流量和保留的脑血管反应性有关。

背景技术与年龄相关的动脉僵硬和不良脑部健康之间的关联所依据的机制仍然难以捉摸。可能与脑血流（CBF）稳态有关。这项研究评估了老年人的主动脉硬化与静息CBF和脑血管反应性（CVR）的关系。方法研究了范德比尔特记忆与衰老项目的参与者，他们没有临床痴呆，中风和心力衰竭，包括认知能力正常的老年人（n = 155；年龄为72±7岁；男性为59％）或轻度认知障碍（n = 115）。 ；年龄：73±7岁；男性占57％）。从心脏磁共振定量主动脉脉搏波速度（PWV；米/秒）。从伪连续动脉自旋标记磁共振成像中定量静息CBF（每100毫升每分钟毫升）和CVR（高碳酸血症性高氧刺激对CBF的反应）。线性回归模型将主动脉PWV与区域CBF相关联，针对年龄，种族/族裔，教育程度，弗雷明汉中风风险状况（糖尿病，吸烟，左心室肥大，普遍的心血管疾病，心房颤动），高血压，体重指数，载脂蛋白E4进行调整（APOEε4）状态和局部组织体积。重复测试PWV×APOEε4相互作用的模型。敏感性分析排除了患有心血管疾病和心房颤动的参与者。结果在认知能力正常的参与者中，较高的主动脉PWV与较低的额叶CBF有关（β= -0.43； P = 0。04）和全脑较高的CVR（β= 0.11; P = 0.02），额叶（β= 0.12; P <0.05），颞叶（β= 0.11; P = 0.02）和枕叶（β= 0.14） ； P ＝ 0.01）。在认知正常的APOEε4携带者中，发现的结果更为明显，其中PWV较高与全脑CBF较低（β= -1.16; P = 0.047），颞叶CBF较低（β= -1.81; P = 0.004）有关。颞叶CVR（β= 0.26; P = 0.08），尽管最后的结果未达到先验显着性阈值。在敏感性模型中，结果相似。在患有轻度认知障碍的受试者中，较高的主动脉PWV与枕叶的CBF较低有关（β= -0.70； P = 0.02），但是当排除患有心血管疾病和房颤的受试者时，这一发现会减弱。在患有轻度认知障碍的APOEε4携带者中，与较低颞叶CBF有关的PWV较高时，发现更为明显（β= -1.20； P = 0.02）。结论认知正常的成年人，尤其是遗传易感性阿尔茨海默氏病的个体中，较大的主动脉硬化与较低的区域CBF和较高的CVR有关。尽管保留了脑血管储备能力，但中央动脉硬化仍可能有助于区域CBF的降低。