Will a pregnancy outside the womb be possible? Here’s what Israeli scientists found

Israeli scientists cultured 250 cell embryos in mouse fetuses with fully formed organs using artificial uteri, in a breakthrough, they say, could pave the way for human gestation outside the womb.

The advance was published yesterday in the magazine Nature under the title Ex utero embryogenesis of mice from pre-gastrulation to late organogenesis.

“We’ve grown hundreds of mice this way, in a method that took seven years to develop, and I’m still mesmerized every time I see it.”, said to The Times of Israel Professor Jacob Hanna, stem cell biologist at the Weizmann Institute of Science.

Hanna said her research will advance understanding of organ formation in mammals – and may facilitate medical advancements – by allowing unprecedented views on how the process developed, without the need to imagine inside uterus. “This could be relevant to other mammals, including humans, although we recognize that there are ethical issues with growing humans outside the body,” he said.

“The power to develop embryos beyond the time we are currently doing is the challenge and what has been tried for a long time. The study refers to how to follow the development of an immature but already formed fetus to reach term, which would be for cases of very premature birth. But from the embryo it’s a much bigger challenge. The reality is that what seems impossible today will surely be achieved at some point ”. Before consulting Infobae, the fertility doctor Sergio Pasqualini (MN 39914) admitted that “personally I thought that with a uterus transplant it would be very difficult for a baby to develop and be born there, and yet it is come.”

For the director of the Halitus Medical Institute, “a priori, it is difficult to believe that an embryo can at some point lead to the birth of a normal baby because of all that intrauterine development involves, and all that is known to be at stake ”. “But reality often goes beyond fiction, so hopefully at some point that can happen with that as well. Even if we must not lose sight of the fact that while this work shows great progress, it has its limits, ”he added.

Although scientists have been trying for decades to conceive mammals outside the body, success has been limited to very early embryos that are grown in the lab for a short time or to fetuses that are removed from the uterus. after the formation and growth of their organs in the laboratory. laboratory.

When the Philadelphia Children’s Hospital created an artificial uterus in 2017 that successfully cultivated fetuses of lambs for more than four weeks, the lambs already had their organs at the start of the experiment. Hanna, on the other hand, started out with embryos made up of only stem cells, and watched “in amazement” as the organs of mice – animals that have a rapid gestation period of only 19 days – develop before her eyes.

“The mouse embryo develops in a few days and whatever is done in the mouse, extrapolating it to larger mammals can be much more difficult, surely it will be much more difficult Pasqualini reflects. That there are people who are studying and trying to develop this is a way to increase knowledge a lot, and if at some point this could be done, other considerations would come in: risks of babies growing up with problems. because it couldn’t already be said. to be born, because it would be different. Everything remains to be seen and it is fascinating to see how we can move forward in things that at one point seem or seemed impossible ”.

“We took mouse embryos from the mother on day 5 of development, when it was only 250 cells, and we had them in the incubator from day 5 to day 11, by which time all his organs had grown “, the researchers pointed out. And they added, “On day 11, they are making their own blood and have a beating heart, a fully developed brain. Anyone would look at them and say, “This is clearly a mouse fetus with all the characteristics of a mouse.” He went from a ball of cells to an advanced fetus. “

The fetuses were healthy but died at 11 days, as this is currently the maximum time they can develop in the artificial uterus and cannot be transplanted into the uterus of a mouse. Hanna hopes to develop her technology to bring mice to term.

His method is to place the embryos in a special liquid to nourish the embryonic cells in a laboratory dish and float them in the liquid. With this step, they were able to duplicate the first stage of embryonic development, in which the embryo multiplies tenfold.

“The key to our success is that we have developed this special incubator system in which each embryo is in a vial with liquid, and the vial is turned to make sure it doesn’t stick to the sides. The incubator creates all the conditions conducive to its development “he explained.

“What made this possible was the seven-year journey that took us to develop the fluid, which actually provides the embryo with all the nutrients, hormones and sugars it needs, and the incubator, a bespoke electronic device that controls gas concentration, pressure and temperature, ”he said.

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