Scientists grow synthetic mouse embryos from stem cells

Whether naturally or through IVF, conception usually requires an egg and a sperm to get things started. But now, researchers from the Netherlands have managed to skip that step and grow model mouse embryos by combining stem cells instead.The technique can help us better understand the early days of life, and may lead to more effective ways to treat infertility or genetic diseases.
In the first few days after fertilization, the developing embryo takes the form of a blastocyst, a hollow sphere containing a small cluster of less than 100 cells. The inner cells are the beginnings of the embryo itself, while the outer shell will become the placenta.
Researchers from the MERLN Institute and the Hubrecht Institute in the Netherlands took stem cell lines from these two components, grew them in culture and multiplied them. Then, they combined them in artificial environments to see if they would still communicate properly and form the spherical shape. These artificial blastocysts were dubbed “blastoids.”
Not only did the blastoids successfully form, they could even implant into the uterus and kickstart pregnancy. They weren’t able to produce viable embryos, but the project was able to teach the researchers more about the murky early stages of development, including the fact that the inner cells dictate the growth of the outer ones.
“It is the embryonic cells that instruct the placental cells how to organize and to implant in utero,” says Nicolas Rivron, lead researcher on the team. “By understanding this molecular conversation, we open new perspectives to solve problems of infertility, contraception, or the adult diseases that are initiated by small flaws in the embryo. Our research helps to understand the perfect path an early embryo must take for a healthy development.”
With the new technique, scientists will be able to grow large numbers of model embryos to study how environmental factors influence development and disease, without needing to experiment on animals.
“This research opens the path to a new biomedical discipline,” says Clemens van Blitterswijk, an author of the study. “We can create large numbers of model embryos and build up new knowledge by systematically testing new medical techniques and potential medicines.”