Turco, M. Y. et al. Nature 564, 263–267 (2018).

The placenta connects mother and fetus, enables nutrient and waste exchange, and performs other functions. For obvious reasons, this organ is difficult to study in humans. Turco et al. generated organoids that model the fetal contribution to the placenta, the trophoblast. The researchers defined conditions that allow the growth and propagation of these trophoblast organoids, thereby making it possible to maintain organoids for a year in culture. However, because the placental isolates used as the source material also contain maternally derived cells, care has to be taken to verify the fetal origin of the organoid cultures. The researchers confirmed the trophoblast nature of the organoids on the basis of previously established criteria such as marker gene and microRNA expression, as well as others. Furthermore, the organoids exhibited structural characteristics of the placenta and secreted appropriate metabolites and hormones. Trophoblast organoids could help researchers investigate placental development and disfunction.