Moving Domain Computational Fluid Dynamics to Interface with an Embryonic Model of Cardiac Morphogenesis

• DOI: 10.1371/journal.pone.0072924
• Publication Date: 2013-08-23T21:07:01Z
• Authors: Juhyun Lee; Mahdi Esmaily Mog...; Ethan Kung; Hung Cao; Tyler Beebe; Yury Miller; Beth L. Roman; Ching-Ling Lien; Neil C. Chi; Alison L. Marsden; Tzung K. Hsiai
• Keywords: 0301 basic medicine; General Science & Technology; Science; Biomedical Engineering; 610; Bioengineering; Cardiovascular; 03 medical and health sciences; Engineering; Models; 616; Morphogenesis; Animals; Computer Simulation; Fluid Mechanics and Thermal Engineering; Zebrafish; Pediatric; 0303 health sciences; Mechanical Engineering; Q; R; Hemodynamics; Models, Cardiovascular; Heart; Heart Disease; Hydrodynamics; Congenital Structural Anomalies; Medicine; Rheology; Shear Strength; Algorithms; Blood Flow Velocity; Research Article

Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP) (y1) transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development. The CFD simulations were validated with particle image velocimetry (PIV) across the atrioventricular (AV) canal, revealing an increase in both velocities and heart rates, but a decrease in the duration of atrial systole from early to later stages. At 20-30 hours post fertilization (hpf), simulation results revealed bidirectional WSS across the AV canal in the heart tube in response to peristaltic motion of the wall. At 40-50 hpf, the tube structure undergoes cardiac looping, accompanied by a nearly 3-fold increase in WSS magnitude. At 110-120 hpf, distinct AV valve, atrium, ventricle, and bulbus arteriosus form, accompanied by incremental increases in both WSS magnitude and ∇P, but a decrease in bi-directional flow. Laminar flow develops across the AV canal at 20-30 hpf, and persists at 110-120 hpf. Reynolds numbers at the AV canal increase from 0.07±0.03 at 20-30 hpf to 0.23±0.07 at 110-120 hpf (p< 0.05, n=6), whereas Womersley numbers remain relatively unchanged from 0.11 to 0.13. Our moving domain simulations highlights hemodynamic changes in relation to cardiac morphogenesis; thereby, providing a 2-D quantitative approach to complement imaging analysis.