Iranmanesh Faezeh, Nazari Mohammad Ali
Department of Mechanical Engineering, College of Engineering, University of Tehran, Tehran 1439955961, Iran e-mail:
J Biomech Eng. 2017 Aug 1;139(8). doi: 10.1115/1.4037038.
Tumor growth being a multistage process has been investigated from different aspects. In the present study, an attempt is made to represent a constitutive-structure-based model of avascular tumor growth in which the effects of tensile stresses caused by collagen fibers are considered. Collagen fibers as a source of anisotropy in the structure of tissue are taken into account using a continuous fiber distribution formulation. To this end, a finite element modeling is implemented in which a neo-Hookean hyperelastic material is assigned to the tumor and its surrounding host. The tumor is supplied with a growth term. The growth term includes the effect of parameters such as nutrient concentration on the tumor growth and the tumor's solid phase content in the formulation. Results of the study revealed that decrease of solid phase is indicative of decrease in growth rate and the final steady-state value of tumor's radius. Moreover, fiber distribution affects the final shape of the tumor, and it could be used to control the shape and geometry of the tumor in complex morphologies. Finally, the findings demonstrated that the exerted stresses on the tumor increase as time passes. Compression of tumor cells leads to the reduction of tumor growth rate until it gradually reaches an equilibrium radius. This finding is in accordance with experimental data. Hence, this formulation can be deployed to evaluate both the residual stresses induced by growth and the mechanical interactions with the host tissue.
肿瘤生长是一个多阶段过程，已从不同方面进行了研究。在本研究中，尝试构建一个基于本构结构的无血管肿瘤生长模型，其中考虑了胶原纤维引起的拉伸应力的影响。使用连续纤维分布公式将胶原纤维作为组织结构中各向异性的来源加以考虑。为此，实施了有限元建模，其中将新胡克超弹性材料赋予肿瘤及其周围的宿主组织。肿瘤具有一个生长项。生长项在公式中包括营养浓度等参数对肿瘤生长的影响以及肿瘤的固相含量。研究结果表明，固相减少表明生长速率和肿瘤半径的最终稳态值降低。此外，纤维分布影响肿瘤的最终形状，并且可用于控制复杂形态下肿瘤的形状和几何结构。最后，研究结果表明，随着时间推移，作用于肿瘤的应力会增加。肿瘤细胞的压缩导致肿瘤生长速率降低，直至逐渐达到平衡半径。这一发现与实验数据相符。因此，该公式可用于评估生长诱导的残余应力以及与宿主组织的力学相互作用。
