Department of Mechanical Engineering, The University of Texas at San Antonio, TX 78249, United States.
Department of Mechanical Engineering, The University of Texas at San Antonio, TX 78249, United States.
J Biomech. 2022 Jul;140:111165. doi: 10.1016/j.jbiomech.2022.111165. Epub 2022 May 27.
Blood vessels are often subjected to axial twisting during body movement or surgery. Sustained twisting may lead to blood vessel growth and remodeling, however, it remains unclear how the extracellular matrix in the blood vessels remodel under sustained axial twisting. This study aimed to develop a computational model to simulate stress-induced growth and remodeling (G&R) of thin-walled blood vessels under axial twisting. Cylindrical vessels were subjected to a step increase in axial torque while the axial stretch and lumen pressure remained constant. The vessel walls were modeled based on the constrained mixture theory given as microstructure-based discrete fiber families with isotropic matrix structure models. Simulation results demonstrated that in response to a constant twist angle loading, arterial wall thickness, mass, and twisting torque gradually increase towards a new steady state. However, the stress and mass decrease in one diagonal fiber family while increasing in the other diagonal fiber family before reaching plateaus. A novel finding was that the two helical collagen fiber families showed different growth rates and patterns during remodeling, driven by the different fiber stresses generated by the twisting, and led to non-symmetric material properties. This study sheds new light on arterial wall remodeling under axial twisting.
血管在身体运动或手术过程中经常受到轴向扭转。持续的扭转可能导致血管生长和重塑，但目前尚不清楚血管在持续轴向扭转下的细胞外基质如何重塑。本研究旨在开发一种计算模型，以模拟轴向扭转下薄壁血管的应力诱导生长和重塑（G&R）。在轴向拉伸和管腔压力保持不变的情况下，圆柱形血管受到轴向扭矩的阶跃增加。血管壁基于约束混合理论建模，离散纤维家族作为微观结构基础，具有各向同性基质结构模型。模拟结果表明，在恒定扭转角加载下，动脉壁厚度、质量和扭转扭矩逐渐增加，达到新的稳定状态。然而，在达到稳定状态之前，一个对角纤维家族的应力和质量减小，而另一个对角纤维家族的应力和质量增加。一个新的发现是，在重塑过程中，两种螺旋胶原纤维家族表现出不同的生长率和模式，这是由扭转产生的不同纤维应力驱动的，导致材料性能不对称。本研究为轴向扭转下的动脉壁重塑提供了新的视角。
