In a column published on April 22, titled « Cher Frankenstein », the author compares research on human-animal chimeras to the criminal activities of Nazi doctors during World War II, and the researchers involved, to Joseph Mengele. Chimeric embryos undoubtedly raise important ethical questions. However, crossing the famous Godwin point (1) on the occasion of two scientific publications, one French, the other Sino-American, does not enrich the debate. Quite the contrary. This complex and serious subject requires informed and nuanced reflection.
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The creation of human-animal chimeras is not a new method. Cancer research has used a similar experimental system for years to study human tumor cells. In the field of regenerative medicine, numerous publications report the injection of human cells into mice or monkeys, in the fetus or in the adult organism, including in the brain, in order to study their therapeutic potential. with a view to treating neurodegenerative pathologies such as Parkinson’s disease. No voice has been raised to denounce this work, the medical interest of which has never been debated.
No ethical or civilizational dangers
Our research work, like that of the Sino-American team, consists of introducing human stem cells into embryos of animals, mice, pigs, rabbits, and monkeys. These experiences have been duly validated by ethics committees and do not violate any French or international regulations in this area. Unless one imagines a global collusion involving all ethics committees, learned societies and scientific and medical academies, it must be admitted that supervised research on human-animal embryonic chimeras does not represent ethical or civilizational dangers such as invoked by some sensational articles.
Like any scientific or technological advance, we must measure the benefits and the possible risks. In the case of human-animal chimeras, their first merit will be to limit the use of human embryos for research. They will allow us to deepen our knowledge of the development of the human embryo and fetus, identify the genetic mutations responsible for developmental abnormalities, and improve the efficiency of medically assisted procreation techniques. The researchers were the first to alert to the ethical questions raised by this research, in particular when chimerism can concern the development of the brain, which could then lead to the emergence of a primitive form of human consciousness in animals. They will implement all the technical procedures to block these particular forms of chimerism. Let us recall that the new law relating to bioethics proposes to regulate this type of research, by entrusting their supervision to the Biomedicine Agency.
The goal of human-animal chimeras technology is not to create humanized animals, much less half-human, half-animal living organisms. This involves replacing human stem cells in the embryonic environment to study their function and potential. These chimeric embryos constitute a valuable alternative for deciphering the genetic mechanisms of human embryonic development, and thus contribute to the base of knowledge essential for the development of reproductive medicine and regenerative medicine.