Huang Siyao, Huang Hsiao-Ying S
Faculty Research and Professional Development Grant, North Carolina State University, Raleigh, NC 27695, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2012;2012:6645-8. doi: 10.1109/EMBC.2012.6347518.
The heart valve tissue mainly contains collagen fibers and valve interstitial cells (VICs) and constantly experiences different stress states during cardiac cycles. Due to the anisotropic architecture of collagen fibers and highly inhomogeneous cell population, the mechanical behavior of the heart valve becomes more complicated. It is known that external mechanical stimuli can lead to extracellular matrix (ECM) remodeling, cellular mechanotransduction, cell migration, and collagen synthesis; however, the mechanism of matrix-to-cell stress transfer remains unclear. Current study presents heterogeneously distributed collagen fibers responsible for transmitting forces into cells by an image-based finite element analysis incorporating histological photomicrographs of porcine heart valve tissues. Besides, nonlinear and anisotropic material properties tissue models are incorporated to quantify and visualize the overall stress distributions in heart valve tissues. By establishing an effectively predictive method with new computational tools and by performing virtual experiments on the heart valves, the role of load transmission in heart valves is clarified. The current study completely illustrates the stress distribution around cells and demonstrates the force transmission and reception between cells and matrix in the heart valve tissue. Therefore, our developed image-based finite element models provide new insights not only into clarifying the role of the force transmission and reception between heterogeneously distributed collagen fibers, but also a better understanding of relationships between the mechanical stimuli, cellular mechanotransduction, cell migration, matrix synthesis, and tissue remodeling in heart valves.
心脏瓣膜组织主要包含胶原纤维和瓣膜间质细胞（VICs），并在心动周期中不断经历不同的应力状态。由于胶原纤维的各向异性结构和高度不均匀的细胞群体，心脏瓣膜的力学行为变得更加复杂。已知外部机械刺激可导致细胞外基质（ECM）重塑、细胞机械转导、细胞迁移和胶原合成；然而，基质到细胞的应力传递机制仍不清楚。当前的研究通过结合猪心脏瓣膜组织组织学显微照片的基于图像的有限元分析，展示了负责将力传递到细胞中的异质分布胶原纤维。此外，还纳入了非线性和各向异性材料特性的组织模型，以量化和可视化心脏瓣膜组织中的整体应力分布。通过使用新的计算工具建立有效的预测方法，并对心脏瓣膜进行虚拟实验，阐明了负荷传递在心脏瓣膜中的作用。当前的研究完整地说明了细胞周围的应力分布，并展示了心脏瓣膜组织中细胞与基质之间的力传递和接收。因此，我们开发的基于图像的有限元模型不仅为阐明异质分布胶原纤维之间的力传递和接收作用提供了新的见解，也有助于更好地理解心脏瓣膜中机械刺激、细胞机械转导、细胞迁移、基质合成和组织重塑之间的关系。
