"Sleeping beauty sleep"

Automatically stored design

The development of human embryos (the picture shows a five-week-old embryo) can be artificially paused.

(Bild: stock.adobe.com/Tatiana Shepeleva)

The development of human embryos can be artificially paused. This has now been discovered by a research team from Vienna in experiments with stem cell models. The mechanism could be useful in artificial fertilization, they say.

According to the study, embryos have retained a phylogenetically ancient mechanism for taking a break - known as diapause - during development. This is not used in a natural pregnancy, but could provide more temporal flexibility in artificial fertilization, writes the team led by biologist Nicolas Rivron, who conducts research at the Institute of Molecular Biotechnology (IMBA).

Pause obligatory for many mammals
Many mammals, such as deer, seals and skunks, are obliged to take developmental breaks for a few weeks or months as early embryos so that they are not born under poor conditions, but at the desired time: In late spring, when food is plentiful and they have enough time to grow big and strong before the next cold winter.

Signaling pathway is artificially interrupted
This rest period is initiated shortly before the embryo implants in the uterus, Rivron explains in a press release. It can also be induced in human stem cell models, the blastoids, which resemble early stages of embryonic development, by interrupting a signaling pathway called "mTor". It controls the growth, maturation and proliferation of cells. The embryonic models are awakened from their "slumber" when the mTor signaling pathway is reactivated.

Interesting for artificial fertilization
"They then resume their normal development," reports the research team in the study, which was published in the journal "Cell". "Such a dormant state could provide a larger window of opportunity to assess the health of the embryo during in vitro fertilization treatment." It might also be possible to "synchronize the embryo with the mother to improve implantation in the uterus".