Department of Biomedical Engineering, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, United States.
Biomaterials. 2013 Oct;34(31):7575-83. doi: 10.1016/j.biomaterials.2013.06.035. Epub 2013 Jul 13.
Although vascular smooth muscle cells (VSMCs) are pivotal in physiology and pathology, there is a lack of detailed morphological data on these cells. The objective of this study was to determine dimensions (width and length) and orientation of swine coronary VSMCs and to develop a microstructural constitutive model of active media. The dimensions, spatial aspect ratio and orientation angle of VSMCs measured at zero-stress state were found to follow continuous normal (or bimodal normal) distributions. The VSMCs aligned off circumferential direction of blood vessels with symmetrical polar angles 18.7° ± 10.9°, and the local VSMC deformation was affine with tissue-level deformation. A microstructure-based active constitutive model was developed to predict the biaxial vasoactivity of coronary media, based on experimental measurements of geometrical and deformation features of VSMCs. The results revealed that the axial active response of blood vessels is associated with multi-axial contraction as well as oblique VSMC arrangement. The present morphological database is essential for developing accurate structural models and is seminal for understanding the biomechanics of muscular vessels.
尽管血管平滑肌细胞（VSMCs）在生理学和病理学中起着关键作用，但对于这些细胞的详细形态学数据却知之甚少。本研究的目的是确定猪冠状动脉 VSMCs 的尺寸（宽度和长度）和方向，并开发一种主动介质的微观结构本构模型。在零应力状态下测量的 VSMCs 的尺寸、空间纵横比和方向角呈现连续正态（或双峰正态）分布。VSMCs 与血管的环向方向对齐，极角对称 18.7°±10.9°，局部 VSMC 变形与组织水平变形具有仿射关系。基于 VSMCs 的几何和变形特征的实验测量，开发了一种基于微观结构的主动本构模型，以预测冠状动脉介质的双轴血管活性。结果表明，血管的轴向主动反应与多轴收缩以及斜向 VSMC 排列有关。目前的形态学数据库对于开发准确的结构模型至关重要，对于理解肌肉血管的生物力学也具有重要意义。
