Stem cells, grown under the right conditions in vitro, have a remarkable ability to undergo differentiation and self-assembly into complex, three-dimensional organoids, similar in anatomical and functional organization to the developing brain, kidney, gut and other tissues (1). On page eaal1810 of this issue, Harrison et al. (2) show that when mouse embryonic stem cells are cultured together with trophoblast stem cells (which give rise to part of the placenta), the resulting constructs develop into structures that bear a striking resemblance to the mouse embryo after it has implanted into the womb. The finding raises the possibility that by using advanced cell culture techniques, including coculture of multiple cell types, and engineering the appropriate culture microenvironment, it might be possible to model human embryogenesis in a petri dish.
Author: Martin Pera