2023-06-15 16:28:18
A scientific team has generated synthetic human embryos using stem cellsas reported by the British newspaper The Guardian. This represents a new step to the one already announced last summer with the creation in the laboratory a model of synthetic mouse embryos.
This is the international group led by scientists from the University of Cambridge (United Kingdom) and the California Institute of Technology (USA) and directed by Magdalena Zernicka-Goetz, that he published last August in the magazine Nature how they had managed to reproduce outside the uterus and without using ova and spermatozoa what happens in the early stages of mouse development.
Nine months later, yesterday, the authors have announced the realization of the technique with human material during the annual meeting of the International Society for Stem Cell Research in Boston (USA). Affirm that have achieved model embryos, similar to those found in the early stages of human development, and that with this scientific advance they could find answers when investigating genetic disorders and the causes of spontaneous abortions. However, the work is accompanied by ethical and legal problems.
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Without sperm, eggs or uterus: they created synthetic mouse embryos in the laboratory
Without sperm, eggs or uterus: they created synthetic mouse embryos in the laboratory
It should be noted that, as stated The Guardianall full details of the latest work, from the Cambridge-Caltech laboratory, have not yet been published in an article in a scientific journal. But, in the trailer presentation, Zernicka-Goetz described culturing embryos up to a stage just beyond the equivalent of 14 days of development for a natural embryo. Currently, UK law allows human embryos to be studied in the laboratory only up to day 14 of development.
What is known about the progress of synthetic human embryos?
With no more information than the presentation at the congress, the scientific community does not dare to go into detail. As, Alfonso Martinez Arias, ICREA research professor and researcher in Bioengineering Systems-MELIS at Pompeu Fabra University, as collected by SMC, argues that “there is no information available beyond the articles in the press: neither scientific article nor preprint. Therefore, this work cannot yet be verified. It may be an important scientific step, but again, we need to see the full report and data before we can make those claims.”
In the same line it coincides with James Briscoegroup leader and deputy director of research at the Francis Crick Institute, explains to SMC UK that “without a preprint detail or a peer-reviewed article to accompany this news release, it is not possible to comment in detail the scientific importance of this news”. And he defends that “in more general terms, although it is very early, synthetic models of human embryos based on stem cells have great potential. They could provide fundamental insights into critical stages of human development. These are very difficult stages to study and in which many pregnancies fail. A new perspective could help to better understand the causes of miscarriages and unique aspects of human development.”
There is no information available beyond the articles in the press: neither a scientific article nor a preprint. Therefore, this work cannot yet be verified.
It should be noted that, in August, regarding the possibility of replicating the experiment in humans, Zernicka-Goetz stated at a press conference that it was not possible at the moment. “It’s still science fiction“, match then too Llus Montoliu, research professor at the National Biotechnology Center (CNB-CSIC) and CIBERER-ISCIII, who nonetheless pointed out that the possibility raises new ethical dilemmas that will have to be addressed. “It is a chapter of ethics that has yet to be written if one considers reproducing these experiments in the human species.”
Another expert commenting to SMC on the matter, Roger Sturmey, Professor of Reproductive Medicine at Hull York Medical School and Principal Investigator of Maternal and Fetal Health at the University of Manchester, says that “work published in The Guardianis based on a growing base of research showing that stem cells can, under highly specialized laboratory conditions, be engineered to form a structure which resembles the embryonic stage called a blastocyst. In normal development, the blastocyst is an important structure, as it is around this time that the embryo begins the process of implantation in the uterus and pregnancy is established.”
What can it contribute to the knowledge of research in the field of fertility?
We know very little about this stage of human development, “but It is a time when many pregnancies are lost, especially in the context of IVF [fecundaciones in vitro]. Therefore, models are urgently needed to allow us to study this period to help understand infertility and early pregnancy loss. Now we can say that these synthetic embryos share a number of characteristics with blastocysts, But it’s important to recognize that the way synthetic embryos form is different from what happens when a normal embryo forms a blastocyst,” Sturmey said.
It is important to recognize that the way synthetic embryos form is different from what happens when a normal embryo forms a blastocyst.
In presenting the work on mouse models, Zernicka-Goetz, Professor of Stem Cell Biology in Cambridge’s Department of Physiology, Development and Neuroscience, highlighted the achievement. “This has been the dream of our community for years. and the main focus of our work for a decade and we have finally achieved it.
Nine months ago, Zernicka-Goetz explained that for a human embryo to develop successfully, there must be a “dialogue” between the tissues that will become the embryo and the tissues that will connect the embryo with the mother. In the first week after fertilization, three types of stem cells develop: one will eventually become the body’s tissues, and the other two will support the development of the embryo. One of these types of extraembryonic stem cells will become the placenta, which connects the fetus to the mother and provides oxygen and nutrients; and the second is the yolk sac, where the embryo grows and from which it obtains its nutrients in early development.
Many pregnancies fail by the time the three types of stem cells begin to send mechanical and chemical signals to each other, telling the embryo how to develop properly. “Many pregnancies fail at this stage, before most women realize they are pregnant.“, said Zernicka-Goetz, who is also a professor of biology and biological engineering at Caltech. “This period is the foundation for everything else that follows in the pregnancy. If it goes wrong, the pregnancy will fail.”
What are the ethical implications of this work?
It is to be hoped that they will also consider deep ethical and legal issues. Because when they announced this step in mice nine months ago, the scientific community was already putting it on the table. “Yes ok it is premature to talk about impacts in the real world Due to system inefficiency and developmental blockage, it is now within the reach of scientists to generate post-implantation synthetic human embryos with the formation of organs such as brains and beating hearts. Therefore, It is crucial to discuss the ethical and regulatory implications of such methods for studying human embryonic development.“, he stressed Christophe Galicheta scientist at the Francis Crick Institute, to the UK SMC in August.
In in vitro fertilization there is an established legal framework, currently there is no clear regulation that regulates the models of human embryos derived from stem cells.
“Unlike human embryos from in vitro fertilization (IVF), where there is an established legal framework, Currently, there is no clear regulation that regulates the models of human embryos derived from stem cells.. Regulations are urgently needed to establish a framework for the creation and use of human embryo models obtained from stem cells,” Briscoe demands.
In this sense, the head of the group and deputy director of research at the Francis Crick Institute states that “on the one hand, human embryo models derived from stem cells could offer an ethical alternative and more readily available for use than human embryos obtained by IVF. On the other hand, the more similar the models of human embryos obtained from stem cells are to human embryos, the more It is important to have clear rules and guidelines on its use. This poses challenges. How will the comparisons be made, given the difficulty of obtaining and studying human embryos at the appropriate stages”.
Montoliu commented nine months ago that the new technological revolution we are witnessing “is still very inefficient (it is very difficult to obtain stem cells to spontaneously generate a synthetic embryo), but with enormous potential“. And he alluded to scientific advances as spectacular as the birth of Dolly the sheep, in 1997reconstructing an embryo with the nucleus of a somatic cell, or the inducible pluripotent embryonic stem cells, iPS cells, described by Yamanaka in 2006which led him to win the Nobel Prize in Physiology or Medicine in 2012, shared with John Gurdon, pioneer of animal cloning in amphibians.
“A revolution that naturally also raises new ethical dilemmasif we ever think of transferring these experiments to the human species for the generation of synthetic human embryos, perhaps with the aim of using them to obtain new tissues or organs to repair or replace those that no longer exist”, pointed out the CNB- CSIC then.
In summary, experts call for prudence, as Briscoe points out. “It is important that research and researchers in this field proceed with caution, care and transparency. The danger is that missteps or unwarranted claims will have a chilling effect on the public and policy makers, causing a major setback.” for this field”.
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