It was last April when a group of scientists from China and the United States managed to successfully inject human stem cells in monkey blasts. The blastocyst is an embryo at an early stage in mammalian embryonic development.
The team, led by researcher Juan Carlos Izpisua Belmonte, managed to keep some of these embryos made up of two different genetic materials alive for up to 20 days. A “mixed” organism like this is also known as an interspecific chimera.
Despite this important achievement, a couple of months earlier, French scientists Pierre Savatier e Irene Aksoy they had already announced the creation of an embryo with a mixture of monkey and human.
As reported by the Spanish media El País, although it sounds similar to the plot of a science fiction film, it involves 10 human cells in a macaque embryo with a total of 250 cells. They are structures that are the size of a grain of sand.
“In France we are in a situation similar to that of Spain, because we have the same Catholic tradition. The human embryo is considered a sacred entity and working with them is very difficult. I see the creation of human-animal chimeras as an alternative to human embryos in research, ”explained Savatier, whose laboratory at the National Institute of Health and Medical Research, in Lyon, is the only one in Europe that is dedicated to the creation of monkey and human chimeras.
For his part, Aksoy emphasizes that do not use human embryonic cellsRather, they reprogram adult cells, for example the skin, so that they are capable of generating any organ. These reprogrammed human cells are what they inject into macaque embryos to study embryonic development.
“We cultivate embryos very immature and the objective is to study how organs are formed in the earliest stages. It is very basic science, we are not talking about chimerical newborns, ”Savatier said.
“But of course, at some point, some people might want to implant these embryos into a mother and allow them to develop, perhaps at term, and this definitely raises important ethical questions and can be seen as opening a Pandora’s box. These are the issues that ethics committees are discussing in France and elsewhere. “he added.
In this sense, the researcher argued that “if we want to avoid even the slightest risk of creating a human mind in the animal, we have to prevent chimerism in the cerebral cortex at all costs.”
“We also want to prevent chimerism in the germ line (ovules and sperm), to avoid any risk of crossing between chimeric animals and other animals of the same species, which could result in the formation of human-animal embryos,” he said.
In turn, the scientist clarified that his idea is that these human-animal chimeras have the appearance of animals. “We don’t want these human-animal embryos or fetuses to look like a human being”, he delved.
“These creatures, these new biological objects, have to be animal fetuses, perhaps newborns, with some human cells that colonize some specific organs. And that’s it ”, he asserted.
Savatier argues that allowing human-animal chimeras to develop to term could be useful for some applications, “but then the question of the human mind and human consciousness in newborns becomes crucial.”
“In France we are not ready to do this. What we are asking for is the possibility of transfer embryos to surrogate mothers – monkeys, sows or rabbits – to study the earliest stages of development. This new technology offers us the possibility of studying the first stages of human embryonic development without using human embryos ”, he remarked.
“The need for these animals to reach term is primarily to produce transplantable human organs, but in my laboratory we are not focusing on this. Nobody in France. If we were allowed to transfer these embryos to a surrogate mother, we would not attempt to develop them to term. It is not in our objectives ”, he emphasized.
However, he adds that researchers from countries such as the United States and Japan have shown interest in developing these technologies for human organs in animals. “And for this they need permission to carry the embryos to term, or at least almost to term. It is here where the ethical questions are very complex ”, raised.
Finally, on the possibility that in the future there is a creature half human and half monkey, Savatier was emphatic.
“Half and half I don’t think it ever exists, for a simple reason: there is no need for such an experiment from a scientific point of view. We don’t need to make a creature that’s 50% human cells and another 50% monkey cells. I don’t know who could do an experiment like this, ”he mentioned.
“But to create newborn monkeys in which there is a significant colonization of human cells in the pancreas, in the liver or in other organs of medical interest, yes, why not? I don’t know if it will happen, but it is possible, yes ”, he stated.