The first “synthetic” embryos in the world have been created: they can grow in artificial wombs
They were obtained by Israeli researchers at the Weizmann Institute of Science from laboratory-grown mouse stem cells.
No sperms, oocytes, and fertilization, just lab-grown mouse stem cells – that’s how they have created the first “synthetic” embryos in the world grown in artificial wombs to develop part of the brain, intestinal tract, and a beating heart.
The revolutionary feat was achieved by a team of researchers from the Weizmann Institute of Science in Rehovot, Israel, who, after having developed an efficient method to reprogram and restore stem cells at their initial power stage (when they have the greatest potential to specialize in different cell types) and have made an electronically controlled device capable of growing natural mouse embryos outside the uterus they managed to obtain the first synthetic embryos – so called because they were created without fertilized oocytes – and have them develop for more than a week, almost half the gestation time of a female mouse.
The approach, described in detail in a study just published in the scientific journal Cell, is extremely valuable because it could, to a large extent, circumvent the technical and ethical issues involved in the use of embryos in research and biotechnology, paving the way for new horizons in the study of how stem cells form the various organs in the embryo. developing. But above all, in the future, it could make it possible to grow tissues and organs for human transplants.
“The embryo – said Professor Jacob Hanna of the Department of Molecular Genetics of the Weizmann Institute of Science, head of the research team – it’s the best organ-making machine and the best 3D bioprinter – we’ve tried to emulate what it does”.
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Professor Hanna explained that scientists already know how to restore mature cells to their cellular stem; however, to go in the opposite direction, that is, to differentiate stem cells into specialized cells, not to mention whole organs, turned out to be much more difficult.
“Until now, in most studies, specialized cells were often difficult to produce or were aberrant, tending to form tissues that were not well structured and unsuitable for transplantation. – added Hanna -. We have managed to overcome these obstacles, releasing the self-organizing potential encoded in stem cells”.
The first synthetic mouse embryos are grown in artificial wombs
Before using the embryo growth device, the researchers treated a part of the cells in order to activate the expression of two types of genes involved in the development of the placenta and the yolk sac, while the remainder of the stem cells were used. without any particular intervention.
Once mixed together and placed inside the device, the cells aggregated and about 0.5% (50 out of about 10,000) formed spheres, each of which later became an elongated embryo-like structure. And because each group of cells had been marked with a different color, the researchers were able to observe the placenta and the yolk sac, as well as the development of the whole embryo.
Day 8 of the life of a mouse embryo: a synthetic model (top) and a natural embryo (bottom) / Credit: Weizmann Institute of Science
These synthetic models developed normally until day 8.5 – almost half of the mouse’s 20 days of gestation – and compared to natural embryos they showed a 95% similarity both in the shape of the internal structures and in the gene expression patterns of the different cell types. According to scholars, the organs that formed gave every indication of being functional.
“Our next challenge – concluded Hanna – will understand how stem cells know what to do, as they self-assemble into organs and find their way into an embryo. And since our system, unlike a uterus, is accessible, it may prove useful for modeling birth defects and implanting human embryos.”.