Hoth Karin F, Tate David F, Poppas Athena, Forman Daniel E, Gunstad John, Moser David J, Paul Robert H, Jefferson Angela L, Haley Andreana P, Cohen Ronald A
Department of Psychiatry and Human Behavior, Brown Medical School, Providence, RI 02903, USA.
Stroke. 2007 Feb;38(2):308-12. doi: 10.1161/01.STR.0000254517.04275.3f. Epub 2007 Jan 4.
The presence of white matter hyperintensities on brain MRI is common among elderly individuals. Previous research suggests that cardiovascular risk factors are associated with increased white matter hyperintensities. Examining the role of direct physiological measures of vascular function will help to clarify the vascular mechanisms related to white matter hyperintensities. The aim of the present study was to examine the association between endothelial-dependent and endothelial-independent vasodilatation and white matter hyperintensity volume.
Twenty-five older adults with a range of cardiovascular diseases underwent brain MRI and completed assessments of blood vessel integrity using endothelial-dependent and independent flow-mediated dilation of the brachial artery. A semi-automated pixel-based method was used to quantify total brain volume and white matter hyperintensity volume, with white matter hyperintensity volume corrected for total brain volume. The association between measures of flow-mediated dilation and log-transformed white matter hyperintensities was examined.
Correlation analysis revealed that endothelial-dependent vasodilatation was significantly and inversely associated with white matter hyperintensity volume. In contrast, endothelial-independent vasodilatation was not associated with white matter hyperintensities. Neither endothelial-dependent nor endothelial-independent vasodilatation was associated with total brain volume.
These data provide preliminary evidence that the integrity of the vascular endothelium is associated with white matter hyperintensities in older adults with cardiovascular disease. Impaired vascular function may be one mechanism that contributes to the development of white matter hyperintensities in the brain. Additional longitudinal research combining measures of vessel function, neuroimaging and cognition will be helpful in clarifying this potential mechanism.
脑磁共振成像（MRI）上白质高信号在老年人中很常见。先前的研究表明，心血管危险因素与白质高信号增加有关。研究血管功能直接生理指标的作用将有助于阐明与白质高信号相关的血管机制。本研究的目的是探讨内皮依赖性和非内皮依赖性血管舒张与白质高信号体积之间的关联。
25名患有一系列心血管疾病的老年人接受了脑MRI检查，并通过肱动脉的内皮依赖性和非内皮依赖性血流介导的扩张完成了血管完整性评估。采用基于像素的半自动方法量化全脑体积和白质高信号体积，并对白质高信号体积进行全脑体积校正。研究了血流介导的扩张测量值与经对数转换的白质高信号之间的关联。
相关性分析显示，内皮依赖性血管舒张与白质高信号体积显著负相关。相比之下，非内皮依赖性血管舒张与白质高信号无关。内皮依赖性和非内皮依赖性血管舒张均与全脑体积无关。
这些数据提供了初步证据，表明血管内皮的完整性与患有心血管疾病的老年人的白质高信号有关。血管功能受损可能是导致脑白质高信号发展的一种机制。结合血管功能、神经影像学和认知测量的额外纵向研究将有助于阐明这一潜在机制。
