On Wednesday, experts setting up an international scientific framework for this type of research recommended that the 14-day deadline for growing human embryos in the laboratory be extended to enhance knowledge.
In some countries, this research is not framed by law, and even when it is, there is no international legislative coordination. In addition to their local laws, researchers around the world refer to the recommendations of the International Society for Stem Cell Research (ISSCR).
Their updated version was released on Wednesday, for the first time since 2016.
These high-tech recommendations cover a wide range of research with serious ethical implications, from transplantation of human cells into organisms to genome editing, including the formation of organs from stem cells. An area that sometimes limits science fiction and causes fear among the general public.
Among the proposed changes, “perhaps the most important is relaxing the 14-day rule, the maximum limit for growing healthy human embryos in the laboratory,” explains the head of the group of 45 scientists behind the recommendations. Robin Lovell, the Englishman – Badge of the Francis Crick Institute, London.
This panel of experts does not propose a new limit, but recommends exceeding 14 days according to strong scientific reasons and general advice in the country in which the research in question is being conducted.
The 14-day limit after fertilization, at the end of which the embryos must be destroyed, “appears in the law of dozens of countries, including the United Kingdom and Australia,” recalls Robin Lovell-Badge in a commentary published in the medical journal Nature.
In France, the cap was not set by law, but in practice, it was set at seven days. The government wants to officially extend it to 14 days as part of the bioethics act currently being discussed in Parliament.
But for the scientists at the ISSRC, that barrier is already outdated.
When this limit was proposed nearly 40 years ago, no one was able to grow human embryos for more than 5 days or so. Today, however, that prevents us from studying a critical period (in fetal development), ranging from 14 to 28 days, ”says Robin Lovell-Badge.
According to him, the 14-day limit only precedes “the first signs of formation of the central nervous system.”
However, “we know very little about what happens in an embryo” during the period following the 14 days, which is the “black box” of human development.
“From an ethical point of view, we can consider that we need a better understanding of this period of human evolution, given its importance,” continues Robin Lovell-Badge, according to which this could help enhance knowledge about miscarriages, physical anomalies and fetuses.
This type of research has seen remarkable developments in recent years.
In March, two teams of researchers announced that they had produced early-stage human embryos, hoping to learn more about the early stages of evolution.
These experimental structures correspond to the blastocysts, which are the first stage of the embryo, about five days after fertilization of the egg by a sperm.
These so-called “blastoids”, which cannot continue to develop like normal embryos, do not obey the 14-day rule.
But this limitation prevents us from verifying that what happens in these experimental models is consistent with what happens in real embryos, the researchers argue.