It’s not often that the public can watch a science race virtually live. After developmental biologist Magdalena Zernicka-Goetz of the University of Cambridge said during a lecture in Boston last Wednesday that her team had created synthetic human embryos from stem cells, the British Guardian reported for the first time – specialized articles had not yet been published at the time. On Thursday, the competing working group led by stem cell researcher Yaqub Hanna of the Weizmann Institute in Israel uploaded a paper to the online database for advanced biomedical publications BiorXiv, in which they presented a result very similar to that of Zernicka-Goetz, with only one approach difference. Two other working groups also published preliminary reports on work with artificial human embryos on Thursday. And finally, on Friday, the team led by Zernicka-Goetz published an essay in which the researchers presented details of the Boston lecture.
None of these articles have been peer-reviewed by independent experts. However, experts agree that this is an expected but still important step for the field of research. Until now, such experiments have only been described in connection with animal embryos. The competition is not just about scientific fame, but also about the intellectual property rights of the methods. Researchers from the groups led by Zernicka-Goetz and Hanna said they were involved in patent applications.
An entire person has not yet been able to grow from the clumps of cells.
Embryos created from stem cells in the laboratory should be thought of as stacks of cells. They may have the potential to transform into humans, but there are no techniques for that in the lab. And you couldn’t transfer these constructs into a woman’s womb either, because they omit a necessary developmental step.
The researchers therefore also refer to their synthetic embryos as “templates” – possibly useful for regenerative medicine, reproductive medicine and developmental biology. “Furthermore, discussion of this type of embryo production will also pose a new challenge to the legal and ethical framework in Germany and beyond,” write Nils Hoppe and Sara Röttger of the Center for Ethics and Law in the Life Sciences (CELLS) . at the Gottfried Wilhelm Leibniz Universität Hannover in a joint statement on the reports from England and Israel. “Are synthetic embryos less worthy of protection than, for example, surplus embryos from fertility treatments? We will have to reorient ourselves socially.”
Zernicka-Goetz’s team genetically modified human stem cells in such a way that they began to develop not just individual tissue types, but an entire embryo. Instead of genetic engineering, Hanna’s group used a cocktail of biochemicals to trigger this transformation. Experiments in monkeys and mice had already shown that it would be possible to grow whole embryos with different types of cells from individual stem cells. In that respect, transfer to human cells was only a matter of time.
It’s impressive to see “how more than a decade of very fundamental research” led to this result, says Jesse Veenvliet, head of the Stembriogenesis working group at the Max Planck Institute for Molecular Cell Biology and Genetics in Dresden, who was not involved in the work. He describes the resemblance of artificial embryos to natural equivalents as “remarkable, almost uncanny”.
Do the experiments mark a cloning renaissance?
Michele Boiani, head of the “Mouse Embryology” working group at the Max Planck Institute for Molecular Biomedicine in Münster, is also impressed by the work: “I am, however, critical of the linguistic nomenclature used, in which the created embryonic structures are treated as mere ‘models’ of human embryonic development.” As a mouse biologist, he sees things this way: if the developmental function is given, constructs must be considered simply as embryos – regardless of their biological origin. “To the extent that they recapitulate early human development, they should be called embryos and not treated as mere models – especially in the legal sense.”
Ingrid Metzler agrees, she works in the Department of Biomedical Ethics and Health Sciences at the Karl Landsteiner Private University for Health Sciences in Krems. The groups around Hanna and Zernicka-Goetz “seem to suggest that working with stem cell-induced embryo models might be an ethical alternative to embryo research,” says Metzler. “From the group’s point of view, this is an understandable position. But I think it would be rash to make this position a generally valid classification with research on and with these new objects.”
From Michele Boiani’s point of view, the clusters of cells created are not just embryos, but also clones that are grown from stem cells in the laboratory. Thus, the experiments “ultimately represent a renaissance in human embryo cloning.”
With material from the Science Media Center