Key Laboratory of Hydrodynamics (Ministry of Education), Department of Engineering Mechanics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China.
Institute of Mechanobiology and Biomedical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
Biomech Model Mechanobiol. 2020 Apr;19(2):519-531. doi: 10.1007/s10237-019-01226-1. Epub 2019 Sep 7.
The diseases of human blood vessels are closely associated with local mechanical variations. A better understanding of the quantitative correlation in mechanical environment between the current mechano-biological studies and vascular physiological or pathological conditions in vivo is crucial for evaluating numerous existing results and exploring new factors for disease discovery. In this study, six representative human blood vessels with known experimental measurements were selected, and their stress and strain variations in vessel walls under different blood pressures were analyzed based on nonlinear elastic theory. The results suggest that conventional mechano-biological experiments seeking the different biological expressions of cells at high/low mechanical loadings are ambiguous as references for studying vascular diseases, because distinct "site-specific" characteristics appear in different vessels. The present results demonstrate that the inner surface of the vessel wall does not always suffer the most severe stretch under high blood pressures comparing to the outer surface. Higher tension on the outer surface of aortas supports the hypothesis of the outside-in inflammation dominated by aortic adventitial fibroblasts. These results indicate that cellular studies at different mechanical niches should be "disease-specific" as well. The present results demonstrate considerable stress gradients across the wall thickness, which indicate micro-scale mechanical variations existing around the vascular cells, and imply that the physiological or pathological changes are not static processes confined within isolated regions, but are coupled with dynamic cell behaviors such as migration. The results suggest that the stress gradients, as well as the mechanical stresses and strains, are key factors constituting the mechanical niches, which may shed new light on "factor-specific" experiments of vascular cell mechano-biology.
人类血管疾病与局部力学变化密切相关。更好地理解当前力学生物学研究与体内血管生理或病理条件之间的机械环境定量相关性，对于评估众多现有结果和探索新的疾病发现因素至关重要。在本研究中，选择了六个具有已知实验测量值的代表性人体血管，根据非线性弹性理论分析了在不同血压下血管壁中的应力和应变变化。结果表明，传统的力学生物学实验寻求细胞在高/低机械负荷下的不同生物学表达，作为研究血管疾病的参考是不明确的，因为不同的血管存在明显的“特定部位”特征。本研究结果表明，与外表面相比，在高血压下血管壁的内表面并不总是承受最严重的拉伸。主动脉外表面的较高张力支持由主动脉外膜成纤维细胞主导的外向炎症假说。这些结果表明，不同力学小生境中的细胞研究也应该是“疾病特异性”的。本研究结果表明，在壁厚度上存在相当大的应力梯度，这表明在血管细胞周围存在微观尺度的力学变化，并暗示生理或病理变化不是局限于孤立区域的静态过程，而是与细胞迁移等动态细胞行为相关联。结果表明，应力梯度以及机械应力和应变是构成力学小生境的关键因素，这可能为血管细胞力学生物学的“因素特异性”实验提供新的思路。
