A research team creates a living structure in the laboratory without any egg or sperm. It has a brain and a beating heart: it’s a synthetic mouse embryo. This could pave the way for the production of artificial donor organs for humans.
In Germany alone, several thousand people are currently waiting for an organ transplant, often for years. However, a new research breakthrough could pave the way to artificial donor organs created in the lab. For the first time, researchers in Great Britain have succeeded in creating synthetic mouse embryos from stem cells, which form a brain, a beating heart and the basis of all other organs in the body.
“Our mouse embryo model not only develops a brain, but also a beating heart and all the components that will later make up the body,” said Magdalena Zernicka-Goetz, Professor of Mammalian Development and Stem Cell Biology at the University of Cambridge. “It’s just incredible that we’ve come this far.” Their results were published in the journal “Nature”.
Instead of egg cells and sperm, the researchers used stem cells, which can develop into almost any cell type in the body, to create the model embryos. They used three different types of stem cells that occur and play crucial roles in early mammalian development. One type becomes the body and its organs, the other two types become the placenta and yolk sac and support the growth of the embryo.
To guide the development of their synthetic embryo, the researchers assembled stem cells from all three tissue types in the right proportions and in the right environment to encourage their growth and communication with each other. The researchers finally got the stem cells to “talk” to each other. The cells then self-assemble into an artificial embryo.
“What makes our work so exciting is the fact that the resulting knowledge could be used to grow correct synthetic human organs to save lives that are currently lost,” said Zernicka-Goetz. “It should also be possible to manipulate and heal adult organs using the knowledge we have of how to make them.”
With the findings, life in the womb could possibly be saved in the future, because the development of many embryos fails early in pregnancy. This often happens at the point where the three types of stem cells begin to send mechanical and chemical signals to each other that tell the embryo how to develop properly. One is now able to understand “why so many pregnancies fail and how we can possibly prevent that,” said Zernicka-Goetz.
Very similar research results by an Israeli research group had already been published in the journal “Cell” at the beginning of August. These studies would demonstrate “that synthetic embryos that resemble mouse embryos can be created outside the womb,” said Jesse Veenvliet of the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, who was not involved in the studies. According to Veenvliet, the efficiency is still very low. In addition, although the resulting structures look like embryos, they are imperfect and have clearly visible defects. The survival time of eight and a half days, as in the Cambridge study, is also short.
Nevertheless, Veenvliet sees the work of Zernicka-Goetz’s team as an important starting point for further research: “I am sure that there will be a race to produce the first human structures,” says the scientist. This will not be easy, not least because of the crucial differences in the development of mice and humans. However, the question is not whether, but when the transfer of these findings from mouse stem cells to human stem cells will take place.
In Germany, the Embryo Protection Act has so far prohibited experiments on human embryos. However, the legal classification of synthetic embryos is unclear worldwide. In the future, it is likely to increasingly depend on the extent to which they resemble human beings with the capacity to develop and should accordingly be classified as human embryos.
