Scientists manage to create a ‘synthetic’ embryo with a brain and heart in its initial phase

Without the need for eggs or sperm, scientists at the University of Cambridge have managed to create a model of a ‘synthetic’ embryo (embryoid) with a beating heart, brain and other organs in its early stages. The research, which has taken ten years, imitated the natural process using mouse stem cells grown in a laboratory dish and introduced into a machine that simulates the functioning of the uterus, which is why they call it a synthetic embryo. This advance will make it possible to follow the evolution of the embryo live and direct, with which it will be possible to detect congenital malformations and genetic alterations. And it is also a first step that opens the possibility of creating organs in the future, equally artificial, for patients waiting for transplants that never arrive due to a shortage of kidneys, livers or hearts.

Unlike previous studies, the team led by Professor of the Department of Physiology, Development and Neuroscience, Magdalena Zernicka-Goetz, has reached the point where the brain begins to develop. Although it was not completely created, it did begin to solidify, divide into regions, and form the front, which is the largest area. In addition, the neural tube, which is the basic framework of the central nervous system, the preliminary intestinal tube, and external parts that created the proper environment for the evolution of the embryo by providing nutrients and oxygen were molded.

The revolutionary study published this Thursday in the journal ‘Nature’ reports that it has been possible for the “master” cells, which can become any kind of cell, extracted from the rodent to communicate with each other to form the placenta, the yolk sac and the fabrics, a pioneering result in this field. By placing these three ‘pieces’ in the artificial matrix and with a constant movement with which the machine (it is called Ex Utero) imitates the circulation of blood, it is transformed until it has an initial structure of what could be a body with a tail and head. Therefore, it will be possible to directly observe how the organs are created from their first steps.

However, the researcher at the National Center for Biotechnology of the Higher Council for Scientific Research (CSIC), Lluis Montoliu, clarifies that these are not natural embryos. The analysis culminates in the eighth or ninth day of embryonic development, almost halfway through a mouse gestation process of about 20 days, equivalent to more than a month that of humans. For this reason, “this is a first step for the manufacture of organs, although it is still a long way off.” In the future, it is hoped that this method will serve as a guide with human stem cells, Zernicka-Goetz points out. “Similar human models are being made with the aim of generating organs and thus understanding their own mechanisms,” says the Polish researcher and professor at Cambridge.

For now, success is studying the post-implantation stage in the uterus, according to Montoliu, a process hidden from scientists with real embryos. In many countries, including Spain, it is prohibited by law to grow human embryos in the laboratory beyond 14 days. Just after that time, gastrulation occurs, one of the most important phases because the cells reorganize themselves to form the general plan of a body.

“This period of life is very mysterious, so being able to see how it develops on a plate will allow us to understand why so many pregnancies fail,” explains the Polish professor. During the sensitive period – from day 14 to 28 in a human pregnancy – many miscarriages occur and also congenital malformations that lead to lifelong diseases. The embryoids will also make it possible to examine genetic alterations that can lead to pathologies such as cancer.

Once this stage can be overcome in a future study with human cells, which has already been achieved with those of mice, it will be possible to know how to cure adult organs, Zernicka-Goetz illustrates.

This research complements the recent study by the Weizmann Institute of Sciences in Israel. The team led by Professor Jacob Hanna, from the Department of Molecular Genetics at the Rehovot Institute, has achieved similar results with embryos at similar stages. The advances confirm each other, notes Montoliu. “The important thing is that both are capable of generating a synthetic embryo and give rise to the question of what is the function of the genes that compose it.”

By having the initial architecture of the organs, scientists can do research with cells. «It is possible to know the contribution of some genes of unknown function. Activate and deactivate them to see the effects on the formation of the body, “explains Montoliu.