Department of Mechanical Engineering, Union College, Schenectady, New York 12309, USA.
Dev Dyn. 2013 Jul;242(7):801-16. doi: 10.1002/dvdy.23968. Epub 2013 Jun 5.
Looping is a crucial phase during heart development when the initially straight heart tube is transformed into a shape that more closely resembles the mature heart. Although the genetic and biochemical pathways of cardiac looping have been well studied, the biophysical mechanisms that actually effect the looping process remain poorly understood. Using a combined experimental (chick embryo) and computational (finite element modeling) approach, we study the forces driving early s-looping when the primitive ventricle moves to its definitive position inferior to the common atrium.
New results from our study indicate that the primitive heart has no intrinsic ability to form an s-loop and that extrinsic forces are necessary to effect early s-looping. They support previous studies that established an important role for cervical flexure in causing early cardiac s-looping. Our results also show that forces applied by the splanchnopleure cannot be ignored during early s-looping and shed light on the role of cardiac jelly. Using available experimental data and computer modeling, we successfully developed and tested a hypothesis for the force mechanisms driving s-loop formation.
Forces external to the primitive heart tube are necessary in the later stages of cardiac looping. Experimental and model results support our proposed hypothesis for forces driving early s-looping.
looping 是心脏发育过程中的一个关键阶段，在此期间，最初的直心管被转化为更接近成熟心脏的形状。尽管心脏 looping 的遗传和生化途径已经得到了很好的研究，但实际影响 looping 过程的生物物理机制仍知之甚少。我们采用了一种结合实验（鸡胚）和计算（有限元建模）的方法，研究了原始心室移动到共同心房下方的确定位置时早期 s-looping 所需的驱动力。
我们的研究提供了新的结果，表明原始心脏本身没有形成 s-loop 的内在能力，需要外部力量来实现早期 s-looping。这些结果支持了之前的研究，即颈椎弯曲在导致早期心脏 s-looping 中起着重要作用。我们的结果还表明，在早期 s-looping 过程中，体腔褶施加的力不能被忽视，并揭示了心脏胶的作用。我们利用现有的实验数据和计算机建模，成功地为驱动 s-loop 形成的力机制提出了假设并进行了测试。
在心脏 looping 的后期阶段，原始心管外部的力是必要的。实验和模型结果支持了我们提出的早期 s-looping 驱动力假设。
