Scientists produced embryos without using eggs or sperm
A new step has just been taken in the field of biology. Researchers have just succeeded in create mouse embryos from stem cells. For it, they didn’t use sperm, eggs, or uterus, and they let the resulting embryos grow for almost half a gestation period. Towards the end of this period, the embryos already presented all the organ progenitors.
This new study was carried out by scientists from the Weizmann Institute of Science in Israel. It is based on the results obtained during two studies previously carried out by the team. The first concerned the stem cell reprogramming to a “naive” state to allow them to transform into all other cells, including other stem cells. The second study aimed to develop a device that could grow embryos more efficiently outside the uterus.
According to the researchers, the newly developed technology could eventually be used to grow organs for transplants.
The stages of the experience
The scientists combined the two techniques they had developed and were able to obtain the most advanced synthetic mouse embryos never obtained.
The experiment began with naïve mouse stem cells that the researchers had grown in petri dishes for years. These cells were separated into three groups.
The first group contained cells destined to develop into embryonic organs. The other two groups were treated with extra-embryonic tissue regulator genes, the placenta for one of the groups and the yolk sac for the other. The three groups were then mixed in an artificial womb. The latter precisely controls the pressure and oxygen exchanges, and simulates a natural flow of nutrients.
The obtained results
In the artificial womb, the three types of cells began to clump together and form aggregates. These latter had the potential to develop into embryo-like structures. During the experiment, the vast majority of mixtures failed to grow. Only 0.5% were able to do it.
In any case, mixtures that passed the first stage began to form spheres of cells which then elongated to obtain a shape resembling the natural shape of the embryos. The scientists let these “embryos” develop for just over 8 days, which is almost half the gestation period of the mice.
After this time, it was observed that the embryos had been able to form all the organ progenitors. This includes a heart that has started beating, a circulation of blood stem cells, a brain, a digestive system and the beginning of a spine.
Observations showed that the shape of the internal structures and the gene expression patterns of these synthetic embryos corresponded to those of natural embryos at 95%. The organs also appeared to be functional.
According to the researchers, this technique could reduce the need for live animals for laboratory tests. It could also eventually become a source of tissues and organs for transplants.