Fatemifar Fatemeh, Feldman Marc D, Oglesby Meagan, Han Hai-Chao
Department of Mechanical Engineering,University of Texas at San Antonio,San Antonio, TX 78249.
Department of Medicine,University of Texas Health ScienceCenter at San Antonio,San Antonio, TX 78229.
J Biomech Eng. 2019 Feb 1;141(2):0210071-02100710. doi: 10.1115/1.4041966.
Trabeculae carneae account for a significant portion of human ventricular mass, despite being considered embryologic remnants. Recent studies have found trabeculae hypertrophy and fibrosis in hypertrophied left ventricles with various pathological conditions. The objective of this study was to investigate the passive mechanical properties and microstructural characteristics of trabeculae carneae and papillary muscles compared to the myocardium in human hearts. Uniaxial tensile tests were performed on samples of trabeculae carneae and myocardium strips, while biaxial tensile tests were performed on samples of papillary muscles and myocardium sheets. The experimental data were fitted with a Fung-type strain energy function and material coefficients were determined. The secant moduli at given diastolic stress and strain levels were determined and compared among the tissues. Following the mechanical testing, histology examinations were performed to investigate the microstructural characteristics of the tissues. Our results demonstrated that the trabeculae carneae were significantly stiffer (Secant modulus SM2 = 80.06 ± 10.04 KPa) and had higher collagen content (16.10 ± 3.80%) than the myocardium (SM2 = 55.14 ± 20.49 KPa, collagen content = 10.06 ± 4.15%) in the left ventricle. The results of this study improve our understanding of the contribution of trabeculae carneae to left ventricular compliance and will be useful for building accurate computational models of the human heart.
尽管肉柱被认为是胚胎学残余物，但它在人类心室质量中仍占很大一部分。最近的研究发现，在各种病理状态下的肥厚左心室中存在肉柱肥大和纤维化。本研究的目的是比较人类心脏中肉柱和乳头肌与心肌的被动力学特性和微观结构特征。对肉柱和心肌条样本进行单轴拉伸试验，而对乳头肌和心肌片样本进行双轴拉伸试验。将实验数据与Fung型应变能函数拟合，并确定材料系数。测定并比较各组织在给定舒张期应力和应变水平下的割线模量。力学测试后，进行组织学检查以研究组织的微观结构特征。我们的结果表明，左心室中的肉柱比心肌明显更硬（割线模量SM2 = 80.06±10.04 KPa）且胶原含量更高（16.10±3.80%），而心肌的割线模量为SM2 = 55.14±20.49 KPa，胶原含量为10.06±4.15%。本研究结果增进了我们对肉柱对左心室顺应性贡献的理解，并将有助于构建精确的人体心脏计算模型。
