GMOs: make animals sick to hope (…)
Very little” animal models indeed important for human disease, but it is sufficient for the animal to develop some symptoms of the disease to improve knowledge of the pathophysiology. The techniques used were developed in the 1980s. This may involve the insertion, inactivation or mutation of genes. through additive or subtractive transgenesis methods. The advent of new genetic modification methods (for example, using CRISPR/Cas9). ) made these manipulations even easier and increased. The goals of these practices are primarily basic or applied research covering a very wide range of conditions.
To these data, it is necessary to add the animals killed in the farms without being included in the tests.  :
- animals obtained as a result of the creation of a new genetically modified line, but not presenting the desired characteristics: 61,205;
- animals bred and killed (excessive, diseased, etc.) while maintaining a genetically modified line: 609,996.
The result is that, in total, this activity leads to the killing of about 1.1 million animals each year, more than half of them. empty space » far from respect for animals” sensitive creature In accordance with the terms of the 2010 EU directive on the use of animals for scientific purposes.
In China and Japan, these genome changes also apply to non-human primates. The goal is to create lines of animals that carry the pathogenic gene to have an animal model that is physiologically, anatomically, and genetically close to us, presenting certain features of a human disease, often a neurological disease that monkeys do not develop. spontaneous. To save time, researchers also use the cloning method. For example, in June 2019, an autism-related gene (SHANK3) that causes many mice to have difficult social behaviors (without doing much to advance the subject) was inserted into the genome of macaques. . These present with sleep disturbances, motor deficits, and increased repetitive behaviors, as well as social and learning impairments.
These experiments turned out to be dangerous experiments both in terms of technical prowess and ethical implications. Some are worried, if not sure, about the delay in Europe in the face of China, which is less cautious about acceptable behavior in animal experiments. advance » be realistic . Thus, one paper balanced the burden of neurodegenerative diseases, the promise these genetic technologies hold in primates, and the ethical questions raised by associations in Europe and the United States. . But this article neglects to discuss the possibilities of alternative methodologies (organs-on-a-chip, computer simulation, etc.) because the invasive act animal model is anchored in people’s minds. So the bottom line is that Western countries risk losing out to China and Japan in terms of knowledge production.
Users acknowledge the existence of an ethical problem, but it seems that this problem can be easily overcome in a wonderful exercise in cognitive dissonance.
Some procedures go further by manipulating embryos or pluripotent stem cells from several species to create chimeras, animals that carry different genetic inheritance. One advanced goal is to better understand embryonic development. Another goal is the development of organs in animals.” humanized it can then be transplanted into patients waiting for a transplant. It represents the worst imaginable in terms of animal exploitation and objectification. For example, human stem cells were implanted into a sheep embryo, all of which were re-implanted into a sheep’s uterus; The part of the genome that controls the formation of the pancreas was deleted earlier in the embryo and is thought to be replaced by human genes. . At this stage, the embryos are destroyed prematurely, but the authors promise that one day it will be possible to develop a human pancreas in sheep.
The history of xenografts is a long journey of failure . Recently, genetically modified pig organs (kidney, heart) have been transplanted into primates . And in January 2022, a genetically modified pig heart in the United States  was transferred to a patient with heart failure who survived for two months. With the risk of developing infections transmitted by animal tissue, medical barriers are still significant if we want to avoid complete immunodeficiency of the recipient; moreover, this American patient’s graft had just been infected with a swine virus! However, in addition to the development of organ donation, there are other directions of research for the production of tissues and organs that can be transplanted into humans: bio-printing, artificial organs (heart, kidney, pancreas, etc.), more reliable and safety.
Consistent with this work, some groups have produced monkey-human chimeras from macaque embryos. However, the Bioethics Act 2011 stated that “ creation of transgenic or chimeric embryos is prohibited » . But a revision of the law in 2021 removes this ban, provided that it applies to animal embryos implanted with human stem cells, and not the other way around. At the beginning of 2021, without waiting and without respecting the 2011 law, a group of people from Lyon published a study in which pluripotent stem cells were inserted into macaque embryos. . The chimeric embryos lived for a few days, but the goal was to continue development longer until the chimeric animals were born. .
In 2015, the NIH (National Institutes of Health) in the United States announced that it would stop funding this type of research until fundamental ethical thinking was restored. . This moratorium was partially lifted in 2016 under certain conditions, specifically to prevent the brains of these new creatures from being contaminated by human cells. Discussions on this topic are concentrated on three levels: impact on the welfare and interests of these creatures, use of human embryo material, safety (zoonosis risk). .
Researchers claim that they know the limits and will never cross the red line represented by CNS chimeras. But we saw higher than the Chinese teams” have fun to alter genes already involved in central nervous system function in macaques. The introduction of neurons from the human cortex into the mouse brain has also been tested. In fact, the red line has already been crossed. The risk is to get used to it and conclude that we can always retreat.” restriction “ethics.