School of Engineering, Cardiff University, UK.
Centre for Advanced Vehicular Systems and Department of Biological Engineering, Mississippi State University, USA.
J Mech Behav Biomed Mater. 2018 Dec;88:18-28. doi: 10.1016/j.jmbbm.2018.07.038. Epub 2018 Jul 29.
Neonatal heart disorders represent a major clinical challenge, with congenital heart disease alone affecting 36,000 new-borns annually within the European Union. Surgical intervention to restore normal function includes the implantation of synthetic and biological materials; however, a lack of experimental data describing the mechanical behaviour of neonatal cardiac tissue is likely to contribute to the relatively poor short- and long-term outcome of these implants. This study focused on characterising the mechanical behaviour of neonatal cardiac tissue using a porcine model, to enhance the understanding of how this differs to the equivalent mature tissue. The biomechanical properties of neonatal porcine cardiac tissue were characterised by uniaxial tensile, biaxial tensile, and simple shear loading modes, using samples collected from the anterior and posterior walls of the right and left ventricles. Histological images were prepared using Masson's trichrome staining, to enable assessment of the microstructure and correlation with tissue behaviour. The mechanical tests demonstrated that the neonatal cardiac tissue is non-linear, anisotropic, viscoelastic and heterogeneous. Our data provide a baseline describing the biomechanical behaviour of immature porcine cardiac tissue. Comparison with published data also indicated that the neonatal porcine cardiac tissue exhibits one-half the stiffness of mature porcine tissue in uniaxial extension testing, one-third in biaxial extension testing, and one-fourth stiffness in simple shear testing; hence, it provides an indication as to the relative change in characteristics associated with tissue maturation. These data may prove valuable to researchers investigating neonatal cardiac mechanics.
新生儿心脏疾病是一个主要的临床挑战，仅先天性心脏病每年就在欧盟影响 36000 名新生儿。为了恢复正常功能而进行的手术干预包括植入合成和生物材料；然而，缺乏描述新生儿心脏组织机械性能的实验数据可能是这些植入物短期和长期效果相对较差的原因之一。本研究专注于使用猪模型来描述新生儿心脏组织的机械性能，以增强对其与成熟组织差异的理解。通过使用取自左右心室前壁和后壁的样本，采用单轴拉伸、双轴拉伸和简单剪切加载模式来对新生儿猪心脏组织的生物力学特性进行了表征。使用 Masson 三色染色法制备了组织学图像，以评估组织的微观结构和与组织行为的相关性。机械测试表明，新生儿心脏组织是非线性、各向异性、粘弹性和不均匀的。我们的数据提供了描述未成熟猪心脏组织生物力学行为的基线。与已发表的数据进行比较还表明，在单轴拉伸测试中，新生儿猪心脏组织的刚度是成熟猪组织的一半，在双轴拉伸测试中是三分之一，在简单剪切测试中是四分之一；因此，这表明与组织成熟相关的特性的相对变化。这些数据可能对研究新生儿心脏力学的研究人员有价值。
