Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO, USA.
Department of Biomedical Engineering, Washington University, St. Louis, MO, USA.
J Mech Behav Biomed Mater. 2022 Feb;126:105021. doi: 10.1016/j.jmbbm.2021.105021. Epub 2021 Nov 29.
Aortic wall material properties are needed for computational models and for comparisons across developmental and disease states. There has been abundant work in comparing aortic material properties across disease states, but limited work across developmental states. We performed passive biaxial mechanical testing on newborn mouse aorta with (Eln) and without (Eln) elastin. Elastin provides elasticity to the aortic wall and is necessary for survival beyond birth in the mouse. Mechanically functional elastin is challenging to create in vitro and so Eln aorta can be a comparison for tissue engineered arteries with limited elastin amounts. We found that a traditional arterial strain energy function provided reasonable fits to newborn mouse aorta and generally predicted lower material constants in Eln compared to Eln aorta. At physiologic pressures, the circumferential stresses and moduli trended lower in Eln compared to Eln aorta. Increased blood pressure in Eln mice helps to alleviate the differences in stresses and moduli. Increased blood pressure also serves to partially offload stresses in the isotropic compared to the anisotropic component of the wall. The baseline material parameters can be used in computational models of growth and remodeling to improve understanding of developmental mechanobiology and tissue engineering strategies.
主动脉壁材料特性是计算模型和跨发育及疾病状态比较所必需的。已经有大量的工作比较了不同疾病状态下的主动脉材料特性，但在发育状态方面的工作有限。我们对新生小鼠的带有（Eln）和不带有（Eln）弹性蛋白的主动脉进行了被动双轴力学测试。弹性蛋白为主动脉壁提供弹性，是小鼠出生后生存所必需的。在体外创造具有机械功能的弹性蛋白具有挑战性，因此 Eln 主动脉可以作为具有有限弹性蛋白量的组织工程动脉的比较。我们发现，传统的动脉应变能函数为新生小鼠主动脉提供了合理的拟合，并且通常预测 Eln 中的材料常数比 Eln 主动脉低。在生理压力下，Eln 中的周向应力和模量趋势低于 Eln 主动脉。Eln 小鼠中的高血压有助于减轻应力和模量的差异。高血压还可以部分减轻壁的各向同性与各向异性成分中的应力。基线材料参数可用于生长和重塑的计算模型中，以提高对发育力学生物学和组织工程策略的理解。
