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.

中文翻译：

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人血管机械应力和应变变化的比较研究：血管细胞力学生物学的机械参考。

人体血管疾病与局部机械变化密切相关。更好地了解当前机械生物学研究与体内血管生理或病理状况之间在机械环境中的定量相关性对于评估众多现有结果和探索疾病发现的新因素至关重要。在这项研究中，选择了六个具有已知实验测量值的代表性人体血管，并基于非线性弹性理论分析了它们在不同血压下在血管壁中的应力和应变变化。结果表明，寻求在高/低机械负荷下细胞不同生物学表达的常规机械生物学实验作为研究血管疾病的参考尚不明确，因为不同的容器中会出现明显的“特定于地点”的特征。本结果表明，与外表面相比，在高压下血管壁的内表面并不总是遭受最严重的拉伸。主动脉外表面较高的张力支持了由主动脉外膜成纤维细胞主导的由外而内的炎症的假说。这些结果表明，不同机械位的细胞研究也应是“疾病特异性的”。目前的结果表明，整个壁厚均存在相当大的应力梯度，这表明存在于血管细胞周围的微观机械变化，并暗示生理或病理变化并非局限于孤立区域内的静态过程，但会伴随动态单元格行为（例如迁移）。结果表明，应力梯度以及机械应力和应变是构成机械壁ches的关键因素，这可能为血管细胞力学生物学的“特定于因子”的实验提供新的思路。