Effect of spiral artery remodeling on the shear stresses acting on the placental villi structure

During pregnancy, the maternal uterine vasculature undergoes significant remodeling. Histopathological studies have shown that incomplete spiral artery (SA) remodeling is related to pregnancy disorders. The inaccessibility of the placenta to invasive measurements and the limitations of in vivo imaging have hindered our understanding of its development. Computational simulations provide an opportunity to investigate how SA remodeling affects placenta microstructure. We studied the effect of SA remodeling on uteroplacental hemodynamics. Then, we related changes in macroscale hemodynamics to microscale shear stresses (SS) on the placental villi. We computationally modeled a placentone (macroscale model), the placenta functional unit, consisting of a SA, veins, a cavity and a dense-villi region. To reduce the computational cost, we modeled the dense-villi region as a porous medium. Based on the flow field obtained from these simulations, we modeled flow around intermediate villi (microscale model) to quantify SS on the villi surface. Less SA remodeling corresponded with higher velocities in the intervillous space and resulted in higher SS on the villi structure, which can be detrimental. To conclude, our computational model provides a quantitative analysis of the SA remodeling impact on microscale SS acting on the villi structure. Fluid SS on the intermediate villi obtained from our simulations can inform experiments to study their effect on the development or malformation of placental villi.