Open up research on the embryo even further? ⋅ Inserm, Science for health

In France, since 2021, research carried out on the human embryo can extend until the fourteenth day of development. Is this delay ethically legitimate or does it hamper the search for valuable knowledge for reproductive health? Are there alternatives to continue to progress in this area?

An article to be found in the Inserm magazine n°55

This summer, two research teams cultured mouse embryo models in vitro for more than 8 days, nearly half the natural gestation length of rodents. Such advances raise questions about the current framework for research carried out on the human embryo. Authorized and supervised since 2013 in France, these can, since 2021, relate to the development of embryonic cells during their first 14 days, against 7 previously. Is this delay ethically legitimate or does it hamper the search for valuable knowledge for reproductive health? Do animal models allow us to know as much as the human embryo? And what about research on cellular models created to study a specific aspect of embryonic development: should they be limited by the same ethical considerations? At a time when the projects are under recurrent attack from an associative foundation, a clinical researcher and two members of the Inserm ethics committee are analyzing the situation.

Julie Steffann’s analysis

© Coll. private

Very little is known about the physiology of early human embryonic development, while two thirds of embryos do not reach the fetal state, whether in vitro fertilization (IVF) or, no doubt, in vivo, and less than a third of couples have a child following IVF. Today, to compensate for these failures, we are increasing the number of attempts; it would be better to try to understand! Admittedly, animal models and human embryonic models help to formulate hypotheses on the causes of these failures, but they have their limits. For example, the majority of human embryos have chromosomal abnormalities harmful to their development, unlike those of mice. For what ? The law now restricts our research to the first 14 days of the embryo, on the grounds that its nervous system is then formed. However, it is strange to prohibit research, including with strict ethical protocols, in the time window where abnormalities of the nervous, renal and cardiac systems appear. Some believe they are fighting against eugenics in this way, but these fears stem from ideological fantasy: it is extremely difficult to keep embryos alive beyond 6 days! Is it the fear that the embryo will be demystified by a Petri dish? We need a law which regulates instead of prohibiting, and above all a political will which encourages and supports research on the embryo. In a context of public reluctance, our projects are fragile and under attack. However, they are 100% funded by associations, which proves that they raise real expectations within society. One day, we may cure embryos conceived by IVF and affected by genetic disease: new genome editing techniques could correct these defective genes. But upstream, research is essential!

Julie Steffann is a researcher at the Imagine Institute