Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, 14642, USA.
Nat Commun. 2018 Nov 19;9(1):4878. doi: 10.1038/s41467-018-07318-3.
Flow of cerebrospinal fluid (CSF) through perivascular spaces (PVSs) in the brain is important for clearance of metabolic waste. Arterial pulsations are thought to drive flow, but this has never been quantitatively shown. We used particle tracking to quantify CSF flow velocities in PVSs of live mice. CSF flow is pulsatile and driven primarily by the cardiac cycle. The speed of the arterial wall matches that of the CSF, suggesting arterial wall motion is the principal driving mechanism, via a process known as perivascular pumping. Increasing blood pressure leaves the artery diameter unchanged but changes the pulsations of the arterial wall, increasing backflow and thereby reducing net flow in the PVS. Perfusion-fixation alters the normal flow direction and causes a 10-fold reduction in PVS size. We conclude that particle tracking velocimetry enables the study of CSF flow in unprecedented detail and that studying the PVS in vivo avoids fixation artifacts.
脑脊液（CSF）在脑内的血管周围间隙（PVS）中的流动对于清除代谢废物很重要。人们认为动脉搏动驱动了这种流动，但这从未被定量证明过。我们使用粒子追踪技术来量化活体小鼠 PVS 中的 CSF 流速。CSF 流动是脉动的，主要由心动周期驱动。动脉壁的速度与 CSF 的速度相匹配，这表明动脉壁的运动是主要的驱动机制，通过一种称为血管周围泵送的过程。增加血压不会改变动脉直径，但会改变动脉壁的搏动，增加逆流，从而减少 PVS 中的净流量。灌注固定会改变正常的流动方向，并使 PVS 大小减少 10 倍。我们的结论是，粒子追踪速度测量法使 CSF 流动的研究能够达到前所未有的细节水平，并且体内研究 PVS 可以避免固定伪影。
