Synthetic mouse embryo from stem cells which has brain heartbeats

The results are the culmination of more than a decade of research, and they could help researchers understand why some embryos fail while others go on to develop into a fetus as part of a healthy pregnancy. Additionally, the results could be used to guide repair and development of synthetic human organs for transplantation.

The embryo model was developed without eggs or sperm. Instead, the researchers mimicked natural processes in the lab by guiding the three types of stem cells found in early mammalian development to the point where they start interacting. By inducing the expression of a particular set of genes and establishing a unique environment for their interactions, the researchers were able to get the stem cells to "talk" to each other.

The stem cells self-organized into structures that progressed through the successive developmental stages until the synthetic embryos had beating hearts and the foundations for a brain, as well as the yolk sac where the embryo develops and from which it receives nutrients in its first weeks. This is the most advanced stage of development achieved to date in a stem cell-derived model. A major advance in this study is the ability to generate the entire brain, in particular the anterior region, which has been a "holy grail" in the development of synthetic embryos. The researchers found that the extraembryonic cells signal to embryonic cells through chemical signals but also through touch, guiding the embryo development.

Ref:

Gianluca Amadei et al,Synthetic embryos complete gastrulation to neurulation and organogenesis,Nature,10.1038/s41586-022-05246-3