A synergistic in vitro-in silico model of the placental barrier for predicting fetal exposure and toxicity of xenobiotic compounds

胎盘是人体最不了解的器官之一。作为屏障， 胎盘介导氧气、营养物质、胎儿废物和其他废物的运输， 母体循环中存在的化合物。足月胎盘移植是目前最广泛的 使用模型评估运输和屏障功能。不幸的是，这些模型依赖于 只要有新鲜胎盘就行迫切需要标准化的工具， 评估胎盘屏障转运，以预测母体和胎儿的药代动力学（PK）， 胎盘和胎儿毒性。在第一阶段，我们开发并展示了一种生理相关的， 胎盘屏障的微流体模型，包括母体脉管系统、胎盘和胎儿 脉管系统永生化的细胞滋养细胞在该装置中分化为合体滋养细胞， 如通过广泛表征所证实的。模型中的屏障功能通过显示 化合物通过装置的尺寸依赖性渗透性。同时，我们开发并验证了 微流控装置的体外模型，作为开发生理学- 基于高分辨率的经胎盘物种运输模型。在第二阶段，我们将继续 开发和整合我们的体外和计算机组件的工具包。我们将把微流体 模型包括原代细胞（滋养层细胞和内皮细胞）并确定形态学， 它与基于I期细胞系的模型之间的遗传和表型差异。此外，我们将 测试一组化合物的经胎盘转运，包括外源性物质，内源性分子， 脂质、抗体和毒素，用于全面评估屏障功能和物种复制 体内运输同时，我们将开发一个基于生理学（PB）的高分辨率模型， 胎盘，以支持经胎盘物质转运的机制建模。这一模式将 与母体和胎儿PBPK模型整合，以能够预测母体和胎儿PK。数据 从体外实验中获得的将用于表征药物转运的整体水平， 胎盘使用综合工具包。计算模型将考虑被动和主动 运输该平台的开发将有助于预测化学品的负面健康 对人体的影响，并解决了目前体外屏障测试系统的关键局限性。一个多学科 一个在微流控细胞检测和胎盘生物学方面具有专业知识的团队已经组建， 顺利完成拟议项目。通过提供更真实的 胎盘屏障在体外和计算机模拟，工具包承诺建立一个新的范例， 胎盘作为屏障的评估。

The placenta is one of the least understood organs of the human body. Acting as a barrier between mother and fetus, the placenta mediates transport of oxygen, nutrients, fetal waste products and other compounds present in maternal circulation. Full term placental explants are currently the most widely used models for assessing transport and barrier function. Unfortunately, these models are dependent upon the availability of fresh placentas. There is a critical need for standardized tools that quantitatively assess placental barrier transport to enable prediction of maternal and fetal pharmacokinetics (PK) and placental and fetal toxicity. In Phase I, we developed and demonstrated a physiologically relevant, microfluidic model of the placental barrier, comprising the maternal vasculature, placenta and fetal vasculature. Immortalized cytotrophoblasts were differentiated in the device into syncytiotrophoblasts, as verified by extensive characterization. Barrier function in the model was demonstrated by showing size-dependent permeability of compounds across the device. In parallel, we developed and validated an in vitro model of the microfluidic device, as a first step toward development of a physiologically- based, high-resolution model of transplacental species transport. In Phase II, we will continue to develop and integrate our in vitro and in silico components of this tool kit. We will extend the microfluidic model to comprise primary cells (trophoblasts and endothelial cells) and determine morphological, genetic and phenotypic differences between it and the Phase I cell line-based model. Further, we will test transplacental transport for a panel of compounds including xenobiotics, endogenous molecules, lipids, antibodies and toxins, for thorough evaluation of barrier function and replication of species transport in vivo. In parallel, we will develop a physiologically-based (PB), high-resolution model of the placenta to support mechanistic modeling of transplacental species transport. This model will be integrated with maternal and fetal PBPK models to enable prediction of maternal and fetal PK. Data obtained from in vitro experiments will be used to characterize drug transport at the level of the whole placenta using the integrated toolkit. The computational model will account for passive and active transport. The development of this platform will aide in the prediction of chemicals’ negative health effects in humans and address key limitations of current in vitro barrier test systems. A multidisciplinary team with expertise in microfluidic cell-based assays and placental biology has been assembled for the successful completion of the proposed project. By providing a more realistic representation of the placental barrier both in vitro and in silico, the toolkit promises to establish a new paradigm for assessment of the placenta as a barrier.