“These results could help to better understand certain aspects of infertility and improve the results of assisted reproduction,” said Dusko Ilic of King’s College London.
A group of scientists created “embryonic structures” next to an embryo in its infancy, from mouse stem cells, without resorting to fertilization, according to the scientific journal Nature published on Wednesday.
The researchers, who developed “for the first time” in vitro these structures similar to natural embryos at their origin, hope that this work will help understand how the placenta is formed and how the embryo is implanted in the lining of the uterus.
When they are transferred in utero, the cell spheres, obtained from two types of rodent stem cell, activate adaptation mechanisms similar to those observed during implantation in the uterine wall.
Although these early embryonic structures did not evolve to the state of mature embryos, they served as a model to study the development of the embryo at its inception, a stage still little known.
A few days after fertilization, the mammalian ovule normally develops in a blastocyst, which corresponds to the embryo in the early stages of its development. It is then a spherical structure composed of a layer of external cells (the future placenta) that surrounds a cavity filled with fluid that contains a mass of embryonic cells.
“It is the first time that scientists have been able to clarify the molecular mechanisms of implantation (in the uterus) and these results could help to better understand certain aspects of infertility and improve the results of assisted reproduction,” Dr. Dusko Ilic estimates. of King’s College London.
The failure of the development of the embryo would be due to the absence of a third type of cells “that has an essential role in the structuring of the embryo (…) and that is poorly produced by embryonic stem cells,” says another specialist, the Professor Robin Lovell-Badge, according to the Science Media Center (SMC).
Obtaining comparable results with human cells “remains a great challenge” for researchers who would like to create human embryos in this way, according to Dr. Harry Leith of the MRC London Institute of Medical Sciences.