Three-dimensional flow patterns in the feto-placental vasculature system of the mouse placenta

Abstract

In this study, three-dimensional (3D) blood flow of the feto-placental vasculature system of the mouse placenta was investigated using computational fluid dynamics (CFD) methods and finite element analysis. Micro-computerized tomography (micro-CT) images were used to acquire the 3D geometry of the feto-placental vasculature system, and image-processing software has been used to calculate the 3D morphology of the placenta. The flow was analyzed numerically and compared to the experimental data received from the same model. The numerical and experimental results agree well. Experimentally measured time dependent blood velocity data, available in the literature, was used as the inlet boundary condition to represent the fetal blood pulsatile flow. Velocity profiles and pressure distributions are investigated during different phases of the unsteady flow. The results clearly illustrate the important role of the vasculature structure (e.g., diameter and curvature) in the fetal hemodynamics, which to our knowledge has not been examined previously. The data also show that, at each bifurcation, the blood flow velocity decreases significantly in the transition from the parent vessel (i.e., umbilical artery) to the daughter vessels because of the higher total cross-sectional area of the daughter vessels compared to the parent vessel. It can also be observed that pressure drop at the umbilical artery and pressure drop across the arterial trees obtained in this study agree well with the physiological data reported in the literature. Moreover, the velocity profiles after each bifurcation are symmetric. Finally, from the results no secondary flow has been observed in the vasculature system. This study provides a foundation in understanding and modeling the complex structure of the feto-placental vasculature system and serves as a first step towards developing new concepts for computational analysis of the feto-placental vasculature systems of both human and mouse to better understand how the placenta functions and how gas and nutrient exchange between the mother and fetus.

Keywords: Computational fluid dynamics; Feto-placental circulation; Finite element analysis; Mouse placental blood flow.