Mechanical Forces Involved in Cardiac C-Looping

Cardiac looping is a vital morphogenetic process that transforms the initially straight heart tube into a curved tube normally directed toward the right side of the embryo. We examined the role of biomechanical forces during the initial stages of looping, when the heart bends and rotates into a c-shaped tube (c-looping). C-looping consists of two primary deformation components: ventral bending and dextral (rightward) rotation (torsion). Embryonic chick hearts were subjected to mechanical and chemical perturbations, and the experiments were simulated using a computational model. The results suggest that bending is driven primarily by actin polymerization within the heart tube, while rotation is driven by external loads due to the splanchnopleure and omphalomesenteric veins. The results of this study may help investigators searching for the link between gene expression and the mechanical processes that drive looping.