Clark A R, Lin M, Tawhai M, Saghian R, James J L
Auckland Bioengineering Institute , University of Auckland , Auckland , New Zealand.
Obstetrics and Gynaecology , University of Auckland , Auckland , New Zealand.
Interface Focus. 2015 Apr 6;5(2):20140078. doi: 10.1098/rsfs.2014.0078.
The placenta provides all the nutrients required for the fetus through pregnancy. It develops dynamically, and, to avoid rejection of the fetus, there is no mixing of fetal and maternal blood; rather, the branched placental villi 'bathe' in blood supplied from the uterine arteries. Within the villi, the feto-placental vasculature also develops a complex branching structure in order to maximize exchange between the placental and maternal circulations. To understand the development of the placenta, we must translate functional information across spatial scales including the interaction between macro- and micro-scale haemodynamics and account for the effects of a dynamically and rapidly changing structure through the time course of pregnancy. Here, we present steps towards an anatomically based and multiscale approach to modelling the feto-placental circulation. We assess the effect of the location of cord insertion on feto-placental blood flow resistance and flow heterogeneity and show that, although cord insertion does not appear to directly influence feto-placental resistance, the heterogeneity of flow in the placenta is predicted to increase from a 19.4% coefficient of variation with central cord insertion to 23.3% when the cord is inserted 2 cm from the edge of the placenta. Model geometries with spheroidal and ellipsoidal shapes, but the same volume, showed no significant differences in flow resistance or heterogeneity, implying that normal asymmetry in shape does not affect placental efficiency. However, the size and number of small capillary vessels is predicted to have a large effect on feto-placental resistance and flow heterogeneity. Using this new model as an example, we highlight the importance of taking an integrated multi-disciplinary and multiscale approach to understand development of the placenta.
胎盘在整个孕期为胎儿提供所需的全部营养物质。它动态发育，并且为避免胎儿被排斥，胎儿和母体的血液不会混合；相反，分支状的胎盘绒毛“浸浴”在子宫动脉供应的血液中。在绒毛内，胎儿 - 胎盘血管系统也发育出复杂的分支结构，以最大化胎盘与母体循环之间的物质交换。为了理解胎盘的发育，我们必须跨越空间尺度转换功能信息，包括宏观和微观尺度血液动力学之间的相互作用，并考虑孕期动态快速变化的结构所产生的影响。在此，我们展示了迈向基于解剖学的多尺度方法来模拟胎儿 - 胎盘循环的步骤。我们评估了脐带插入位置对胎儿 - 胎盘血流阻力和血流异质性的影响，结果表明，尽管脐带插入位置似乎不会直接影响胎儿 - 胎盘阻力，但预计胎盘内血流的异质性会增加，从脐带中心插入时变异系数为19.4%增加到脐带插入距胎盘边缘2厘米时的23.3%。具有相同体积的球形和椭球形模型几何形状在血流阻力或异质性方面没有显著差异，这意味着正常的形状不对称不会影响胎盘效率。然而，预计小毛细血管的大小和数量对胎儿 - 胎盘阻力和血流异质性有很大影响。以这个新模型为例，我们强调采用综合的多学科和多尺度方法来理解胎盘发育的重要性。
