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The Agence de la biomédecine's Conseil d’orientation has just adopted a framework opinion on research using embryoids[1], which are in vitro models of embryonic development designed exclusively from stem cells. The Conseil d’orientation considers that embryoids offer scientific and medical advances that justify their use in fundamental and applied research. However, it stresses the risks of abuse, and recommends that a specific framework be defined to prevent any risk of unethical behaviour. These models were initially developed in mice in 2018 and then in humans in 2021, and have since raised a number of ethical questions that are being debated within the international scientific community.
France is the only country to have adopted a provision in its law relating to this type of model. The 2021 Bioethics Act stipulates that research aimed at "obtaining in vitro embryonic development models" must be declared to the Agence de la biomédecine, which must seek the opinion of the Conseil d'orientation (articles L2151-6 and L2151-7 of the Public Health Code).
In this context, the Conseil d’orientation wanted to draw up a framework opinion covering all the ethical and scientific questions raised by these models, and attempting to provide some answers based on the current state of knowledge. This is the first document of its kind produced by an ethical body at national and international level.
The Conseil d’orientation considers that human stem cell-based embryo models or embryoids cannot, in essence, be equivalent to natural embryos for two reasons:
Currently, there is an international consensus against the transfer of human embryoids into a human or animal uterus.
The Conseil d’orientation believes that embryoids are particularly valuable models for research, with many potential biomedical applications: more efficient techniques for medically assisted reproduction; pharmacological and toxicological testing; better understanding of developmental abnormalities and pregnancy losses with the possibility of developing preventive treatments; development of cell therapies. Moreover, embryoids represent an interesting alternative from an ethical point of view, because as models they avoid the need for researchers to experiment on human embryos.
The opinion of the Conseil d’orientation proposes authorising research on up to a stage equivalent to the 28th day of development of the natural embryo, with a complete cessation of all experimentation beyond that stage. This would not call into question the current law, which sets a limit of 14 days on the culture of human embryos. Culturing these embryonic models beyond 28 days would not be justified either because, at the current state of science, these models deviate from physiological development and therefore lose their scientific and medical relevance and usefulness. On the other hand, studying these embryoids would make it possible to explore the period of embryonic development known as the "black box", which currently runs from day 14 to the beginning of the second month of the embryo's development. This period includes the gastrulation stage, during which the majority of congenital diseases appear, which is not accessible to research under current regulations.
Nevertheless, these considerations do not exclude the need for increased vigilance for protocols protocols that involve experimentation on embryoids beyond 14 days of culture, with researchers having to justify such an extension on a case-by-case basis.
In order to enable scientific advances, while providing an ethical framework, the Conseil d’orientation proposes that the legislator considers this research in a third specific way, between that for stem cells, which would be too permissive, and that for embryos, which would be too restrictive.
The Conseil d’orientation considers that the risks of commercial exploitation of embryoids and their derivatives (cells, tissues, or organs) should be a point of vigilance. Human embryoids must be used exclusively for scientific research purposes, with criteria of scientific relevance and a medical purpose. In accordance with the International society for stem cell research (ISSCR) recommendations, in vivo implantation should not be allowed.
Finally, the Conseil d’orientation believes that the issue of consent to research needs to be reconsidered, to update the information and consent forms that couples or single women who wish to donate their embryos for research, or individuals who wish to donate somatic cells to create iPS cells, receive and sign.
2. Embryoids ?
« Embryoid » is a generic term. These are "stem cell based embryo models", obtained from embryonic or induced stem cells, capable of reconstituting the first stages of embryonic development in vitro. They can be formed from two cell sources:
These models are capable of reconstituting either part of the embryo or the entire embryo in vitro. They represent an alternative to the use of natural embryos for research. In the general press, they are sometimes wrongly presented as "embryos conceived without gametes" or "synthetic embryos". However, they are not the equivalent of a natural embryo for two reasons:
In the current state of knowledge and technical developments, these models are therefore incapable of reconstructing the whole of embryonic and foetal development in animals. They should not be considered as equivalent to embryos: they are not derived from gametes and are designed as research models.
There is currently no consensus on the status to be given to these models: should they be considered as cultured cells? Should we anticipate improvements in protocols and techniques and already consider them, from an ethical and regulatory point of view, as equivalent to a natural embryo? Or should they be considered as an intermediary between the two?
3. A session on the subject at the Agence de la biomédecine scientific meeting : « Les Rencontres de la biomédecine »
Friday 13 October, from 10.30am to 12.00pm at the Cité Universitaire in Paris, a session entitled "The latest developments in embryonic stem cell research / IPS". Session programme:
Website of the event: www.rencontres-biomedecine.fr/session-13
Press release of the Agence de la biomédecine meeting (in French): https://presse.agence-biomedecine.fr/rencontres-de-la-biomedecine-2023/
[1] A generic term to which the scientists prerfer « stem cell based embryo models »
About the Agence de la biomédecine
The Agence de la biomédecine is a French national health agency created by the 2004 Bioethics Act. It is responsible for organ, tissue and cell procurement and transplantation, as well as human reproduction, embryology and genetics. The Agence de la biomédecine does its utmost to ensure that every patient receives the care they need, in compliance with the rules of health safety, ethics and equity. Through its expertise, the Agence de la biomédecine is the reference authority on the medical, scientific and ethical aspects of these issues.