Your future organ donor may be a synthetic embryo

6. september 2022 kl. 17:41
Your future organ donor may be a synthetic embryo
Illustration: Bigstock.
Embryos created without either egg or sperm, but from stem cells alone, can now form organs.
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“We have created the environment necessary for stem cells to form these embryo-like structures and for them to develop,” Jacob Hanna, the researcher behind the experiment at the Israeli Weizmann Institute of Science, says describing the results he has obtained in his new study.

He has succeeded in creating mouse embryos from stem cells and developing them for eight days.

Here you can see the development of the synthetic embryos from day 5 to 8. Illustration: Figur 3, Post-gastrulation synthetic embryos generated ex utero from mouse naive ESCs.

That may not sound like much, but it means that the mouse embryos have gone through almost half the development that a natural embryo would go through during a pregnancy, since a pregnancy in mice normally only lasts 20 days.

Not quite an embryo

Jacob Hanna calls the formed structures embryoids instead of embryos. By doing that, he plays on the same linguistic difference that separates the words human and humanoid. Humanoid is not quite human, but human-like. In the same way, an embryoid is only embryo-like.

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What Jacob Hanna has created is certainly very embryo-like: 95 percent of the cell structure in the mouse embryoids he has created from stem cells is identical to mouse embryos created naturally.

Here you can see a comparison of the cell composition in synthetic and natural mouse embryos after 8 days:

Illustration: Figur 7, fra studiet om syntetiske fostre.

“We have succeeded in developing them to a stage where they have organs, beating hearts, and the beginnings of a tail,” Jacob Hanna says.

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According to Jacob Hanna, the embryoids’ ability to form organs in particular can be of great importance in the future. Especially for patients who are waiting for a genetically matching organ donor.

The perfect donors

The possibility of developing embryos up to that stage could create new opportunities for patients with failing organs if they can be replicated with human cells.

”It’s time to start the conversation about where the boundaries should be.”
-- Jacob Hanna
There are still patients who die while waiting for a matching organ donor to come along.

If the necessary organs can be grown in embryos created from the patient’s own stem cells, it would be possible to create a genetic match without needing a donor.

The idea of creating organs from the patients’ own cells is not new. In the past, there have been experiments with 3D bioprinting, but it has not been possible to keep the organs functional throughout the process. However, a synthetic embryo could make it possible.

“The holy grail in stem cell research is being able to form organs from patients’ stem cells,” Jacob Hanna says.

“In trying to create organs on their own, we haven’t been able to create an environment where they can develop. That environment can, on the other hand, exist in the synthetic embryos.”

Jacob Hanna has managed to get the synthetic embryos to develop this far due to one of his earlier inventions: a mechanical womb. He hopes that a such a device will eventually be able to develop the embryos to a stage that would correspond to a 40–50 day old natural embryo.

Jacob Hanna hopes to be able to develop a synthetic embryo to approximately this stage. Illustration: Ed Uthman .

Mechanical womb

According to Jacob Hanna, the mechanical womb is the backbone of his research. It works, among other things, because it moves during the process, which increases the amount of nutrition the embryo can absorb.

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Jacob Hanna proved last year that the mechanical womb worked when he took natural embryos from mice and continued their gestation in his device.

The difference between the trial last year and the current trial is that the embryos in the current trial are not created with sperm and egg cells but are instead created directly from stem cells.

Scientists have previously shown that this may be possible, but scientists have never before been able to prove that the embryos could develop. The new experiment now shows that it can be done by developing the synthetic embryos in a mechanical womb.

See the mechanical womb in action here:

Remote video URL

Ethical dilemmas

According to Jacob Hanna, his current research is still far from producing anything that could give rise to ethical issues, as the 5 percent difference between natural and synthetic embryos means that they are not viable and perish relatively early in their development. At the same time, he believes that this research may have the potential to help patients in the future.

“We don’t ban nuclear research because there are people who want to make nuclear weapons, and we don’t ban biotechnology because it can be used to make dangerous diseases,” Jacob Hanna says.

Even if it could be a possibility in the future, it is not something he wants to do, as the purpose of his research is not to clone humans, but to create functioning organs.

“We are far from creating something that is human enough for ethical issues to arise,” Jacob Hanna says.

On the other hand, he does not rule out that research may reach that point in the future.

“This field is developing quickly, so it’s time to start the conversation about where the boundaries should be.”

If we later want and can develop embryos to a point where ethical dilemmas may arise, genetic engineering may be the solution.

“If we want to develop embryos to a later stage, it may be an option to change their genes so that they never develop a brain or maybe even only develop the organs from which we want to harvest cells.”

Jacob Hanna is already working on recreating the experiment with human cells instead of mice cells but has not yet developed human embryos to a significantly far-along stage.

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