Department of Electrical and Mechanical Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan.
Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya, Japan.
Sci Rep. 2022 Mar 30;12(1):5381. doi: 10.1038/s41598-022-09304-8.
Vascular smooth muscle cells are exposed to interstitial flow across aortic walls. Fluid shear stress changes the phenotype of smooth muscle cells to the synthetic type; hence, the fast interstitial flow might be related to aortic diseases. In this study, we propose a novel method to directly measure the interstitial flow velocity from the spatiotemporal changes in the concentration of a fluorescent dye. The lumen of a mouse thoracic aorta was filled with a fluorescent dye and pressurized in ex vivo. The flow of the fluorescent dye from the intimal to the adventitial sides was successfully visualized under a two-photon microscope. The flow velocity was determined by applying a one-dimensional advection-diffusion equation to the kymograph obtained from a series of fluorescent images. The results confirmed a higher interstitial flow velocity in the aortic walls under higher intraluminal pressure. A comparison of the interstitial flow velocity in the radial direction showed faster flow on the more intimal side, where hyperplasia is often found in hypertension. These results indicate that the proposed method can be used to visualize the interstitial flow directly and thus, determine the local interstitial flow velocity.
血管平滑肌细胞暴露于穿过主动脉壁的细胞间隙流中。流体切应力将平滑肌细胞的表型改变为合成型；因此，快速的细胞间隙流可能与主动脉疾病有关。在这项研究中，我们提出了一种从荧光染料浓度的时空变化直接测量细胞间隙流速度的新方法。在离体状态下，将荧光染料填充到小鼠胸主动脉的管腔中并加压。在双光子显微镜下，可以成功观察到荧光染料从内膜侧到外膜侧的流动。通过将一维平流-扩散方程应用于一系列荧光图像的动图，确定了流速。结果证实，在更高的管腔内压力下，主动脉壁中的细胞间隙流速度更高。对细胞间隙径向流速的比较表明，内膜侧的流速更快，而高血压中常发生内膜增生。这些结果表明，所提出的方法可用于直接可视化细胞间隙流，从而确定局部细胞间隙流速度。
