Lab-made mouse embryos grew brains and beating hearts, just like the real thing

The mouse stem cells were grown into synthetic embryos that began developing hearts and brains.

The lab-made embryos were created without any eggs or sperm and were put in a device that looked like a Ferris wheel and lived for over a week. It's less than half the length of a typical mouse pregnancy. In that time, a yolk sac developed around the embryos to provide nutrition, and the embryos themselves developed a number of organs, including the forebrain and midbrain.

"This has been the dream of our community for a long time, and finally, we've accomplished it," said senior study author Magdalena Zernicka-Goetz.

The results of the new work were very similar to those of the previous study, which was published in Cell. The same incubator was used to culture synthetic mouse embryos in the Cell study. Live Science previously reported that the embryo's beat hearts and wrinkled brains before they died.

A human embryo made in the lab.

The two recent studies produced the same embryo. The researchers in the Cell study started by inducing mouse stem cells into a naive state from which they could be transformed into any cell type, such as heart, brain or gut cells. The naive cells were split into three groups. They switched on genes to make the yolk sac in one group but not in the other. They left the last group alone to make babies.

The research group started with three mouse stem cell types instead of just naive cells. One type of stem cell gave rise to the embryo, while the other two went into the placenta and the yolk sac. They observed how the stem cell types interacted, exchanging chemical messages and physically butting up against each other.

It's possible to get clues as to how the earliest stages of human development unfold in humans.

"To be able to see how it happens in a dish, to have access to these individual stem cells, to understand why so many pregnancies fail and how we might be able to prevent that from happening is quite special." We've shown how it can go wrong and how the different types of stem cell have to talk to each other.

In both the Cell and Nature studies, the synthetic embryos were very similar to the real ones. The efficiency of both systems could be improved due to the low proportion of stem cells giving rise to embryos in both experiments. The synthetic embryos did not survive to the ninth day of development, an obstacle that would need to be overcome in follow-up studies.

ethical questions about if and how such technology could be applied to human cells in the future were raised by the research.

It was originally published on Live Science