Data from: Analytical modeling of the feto-placental vasculature system of the placenta: consideration of oxygen transport

The placenta is a transient vascular organ that enables nutrients and blood gases to be exchanged between fetal and maternal circulations. Herein, the structure and oxygen diffusion across the trophoblast membrane between the fetal and maternal red blood cells in the feto-placental vasculature system in both human and mouse placentas are present together as a functional unit. Previous models have claimed that the most efficient fetal blood flow relies upon structures containing a number of ‘conductive’ symmetrical branches, offering a path of minimal resistance that maximizes blood flow to the terminal villi, where oxygen diffusion occurs. However, most of these models have disregarded the actual descriptions of the exchange at the level of the intermediate and terminal villi. We are proposing a ‘mixed model’ whereby both ‘conductive’ and ‘terminal’ villi are presumed to be present at the end of single (in human) or multiple (in mouse) pregnancies. We predict an optimal number of 18 and 22 bifurcation levels in the human and the mouse placentas, respectively. Wherever possible, we have compared our model’s predictions with experimental results reported in the literature and found close agreement between them.胎盘（placenta）是一种暂时性血管器官，可实现胎儿与母体循环之间的营养物质及血液气体交换。本文中，人类与小鼠胎盘的胎儿-胎盘血管系统（feto-placental vasculature system）内，胎儿与母体红细胞之间跨越滋养层膜（trophoblast membrane）的结构与氧气扩散过程，共同构成一个功能单元。既往模型提出，最高效的胎儿血流依赖于带有若干"传导性"对称分支的结构，此类结构可提供阻力最小的通路，使血流最大化流向发生氧气扩散的末端绒毛（terminal villi）。然而，此类模型大多忽略了中间绒毛（intermediate villi）与末端绒毛层面的实际交换过程描述。我们提出一种"混合模型"，假定在单胎（人类）或多胎（小鼠）妊娠末期，同时存在"传导性"与"末端性"绒毛。我们分别预测人类与小鼠胎盘的最优分叉层级（bifurcation levels）数为18级与22级。在条件允许的情况下，我们将模型预测结果与文献报道的实验结果进行了对比，发现二者高度吻合。