An embryo from stem cells
A synthetic mouse embryo with a beating heart and developing brain
Ekaterina Shutova, XX2 century
According to an article published in the journal Nature (Amadei et al., Synthetic embryos complete gastrulation to neurulation and organogenesis), after 10 years of research, scientists have grown a synthetic mouse embryo in a test tube (more precisely, in a cup), which began to form internal organs, including the heart and brain. The creation of the embryo did not require a fertilized egg: it was obtained from stem cells.
"In our mouse embryo model, not only the brain develops, but also the beating heart and other parts that make up the body," says lead author of the study Magdalena Zernicka—Goetz, professor of Mammalian Development and Stem Cell Biology at the University of Cambridge. — It's unbelievable that we've come this far. This has been the dream of our community for many years, the main focus of our work for a decade, and finally we have done it."
For intrauterine development, the embryo needs several types of cells: in addition to embryonic cells, which become tissues and organs of the body, these are cells that form the yolk sac in which the embryo develops, as well as the placenta. In the laboratory, researchers isolated three types of stem cells from embryos and cultured them in a special container, where they stimulated interaction between cells of different types. Day after day, they watched as a group of cells transformed into a more and more complex structure. The model formed by day 8 had the rudiments of a head with an anterior and middle brain, a heart-like structure, a trunk that included a neural tube, a tail rudiment, an intestinal tube, and so on. All this developed, as befits an embryo, in the yolk sac.
Natural (above) and synthetic (below) embryos.
The obtained result opens up new prospects for the study of embryos in the early stages of development. Previously, everything happened only in the womb, so it was difficult to observe the formation of the fetus. Now researchers will be able to get a more detailed understanding of this process, which means to understand why some pregnancies are unexpectedly interrupted in the early stages.
So far, scientists have managed to track only eight days of the development of mouse embryos, but this has allowed them to learn a lot. Embryo models can already be used to test new drugs, and in the future — to create artificial organs. However, this will require human models, not mouse models.
In its current form, the study is not applicable to human embryos, but the authors hope to move on to modeling natural human pregnancies. Of course, in order to proceed to such experiments, it is necessary to solve a number of ethical issues. In any case, it will probably take years before such an experiment can be carried out on human cells.
Note that the first days of embryo development are of great interest to researchers.
"This period of human life is so mysterious that to be able to see how it happens in a cup, to get access to individual stem cells, to understand why so many pregnancies fail and how we could prevent it is a very special opportunity," says Zernicka—Goetz. "We looked at the dialogue that was supposed to take place between different types of stem cells, showed how it happens and what can go wrong in it."
You can see how the heart of a synthetic embryo beats here.
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