Three-Dimensional In Vitro Human Placental Organoids from Mononuclear Villous Trophoblasts or Trophoblast Stem Cells to Understand Trophoblast Dysfunction in Fetal Growth Restriction.

The placenta plays a critical role in the efficient delivery of nutrients and oxygen from mother to fetus to maintain normal fetal growth. Human placental development and function is a highly orchestrated process, which is spatially and temporally controlled by hormones and growth factors. Specialized epithelial cells called trophoblasts play key roles in placental exchange capacity, and their abnormal function and development contribute to many pregnancy complications, including fetal growth restriction (FGR), a condition in which the fetus does not reach its full growth potential in utero. Great variation in the anatomy and development of the placenta in animal model systems (in vivo) and 2D culture model systems of trophoblasts (in vitro) limits our ability to understand pregnancy disorders. Generating in vitro models that recapitulate the unique features of the human placenta has been challenging. Here, we describe detailed methods to isolate mononuclear villous trophoblasts (containing cytotrophoblasts and trophoblast stem cells) from first trimester placentae, and use both these and trophoblast stem cell populations that can be grown long term in a three-dimensional (3D) placental organoid culture system.