Yet again researchers bump into an ethical borderline: On the breeding a human-animal chimera for the purpose of creating substitute organs

The spectacular accounts from science and research do not break off. From increasingly powerful artificial intelligences, genetically modified CRISPR babies, new quantum technologies, prolonging life by modifying our genes, super-medicines, meat from 3D printers to miraculous nanomaterials – the reports about the rapid technological and scientific progress do not find an end. Philosophers, politicians and sociologists have long since been called to evaluate research results and new technological breakthroughs and to discuss their ethical, political and social consequences. This year alone, an EU expert group arguedover the consequences of artificial intelligence and the German Ethics Council discussed genetic manipulation of the human embryo. Both published corresponding recommendations.

Now a new discussion has flared up. It trigger is a new law in Japan, which allows researchers to create hybrid beings made up of human and animal cells, and – and this is the new thing – to bring them into the world. What sounds like a horror story from ancient Greek mythology is intended to produce replacement organs for sick people. That surely sounds great and yields significant benefit to the many people who have to wait (too) long for a donor organ. At the same time such a development is very controversial and even (still!) forbidden in most counties, e.g. in Germany by the Embryo Protection Act.

Already in 1984 researchers succeeded in creating a chimera from goat and sheep. The embryos of two species were blended and the result was a mixed creature. In such a chimera the genetic material from the two sources does not mix. Rather, the cells of both species grow genetically separated from each other. Thus, for example, the pancreas can come from one species, while the liver from another. The resulting creature 35 years ago was a mixture of both animals, which was even reflected in the animal’s behavior. In some respects it was goat-like in other aspects it acted like a sheep.

But now the next step follows: The Japanese scientist Hiromitsu Nakauchi, a researcher from at Stanford University as well as Tokyo University, who has already grown the pancreas glands and kidneys of a mouse in rat embryos, wants to carry out respective experiments with human cells as well. Although animal embryos with human cells have in fact already been produced before, they have never been born into the world. Nakauchi now wants to take this final step. For this purpose, already in March 2019 the Japanese government modified the previous regulation, which prohibited chimeras from growing longer than the 14th day of embryonic development. Although Nakauchi’s experiments will probably not be officially approved until August 2019, a committee of experts has also already spoken in favor of this.

The motivation behind such a step is clear: Such chimeras would carry corresponding organs that consist exclusively of human cells. Organ donations would no longer be necessary. The patient would receive his new kidney or his new salivary gland directly from the body of the chimera, whose embryo had been provided with the very own cells of the patient. This replacement organ would then have the great advantage over a donor organ that it is not being rejected. It would be a revolution in organ transplant medicine: The availability of such implantable organs could save thousands of lives around the world. In the US, for example, in January 2019 there were about 113,000 people on waiting lists for organ donations, and up to 20 people die every day while waiting for a transplant. The voices for liberalizing research in this direction are correspondingly strong.

This has now brought ethicists onto the stage, as well as some politicians. The German SPD’s health expert Karl Lauterbach, for example, speaks of an “ethical mega violation”: „With the breeding of human-animal beings, a limit is crossed which we as humans must not cross. He warns already against attempts in the other direction: After the successful birth of animals with human organs, could then humans not be equipped with animal characteristics? Well, the later argument can easily be dismissed: There is hardly any application for this other direction, quite contrarian to the breeding of perfect replacement organs with the help of animals whose embryos were fed specific human cells. The latter could easily be legally distinguished from the unacceptable case of breeding humans with animal characteristics.

But as crude as the arguments of the politician Lauterbach are, the chimera technology certainly does entail some serious ethical problems. It blurs the boundaries between humans and animals. In the end, this could even lead to the development of mixed creatures, half-human, half-animal (or three-quarter-human, one-quarter-animal, or some other mix). What about the legal rights of such a being? Ethicists also warn against chimeras that can think and even possess a self-consciousness similar to us humans. Since Nakauchi’s experiments use pluripotent stem cells, i.e. cells that can differentiate into any cell type of an organism, would it be possible for human brain cells to form in animals? In fact, one of the biggest fears of researchers arise from the question where exactly these human stem cells will end up in the animal, i.e. what kind of cells they can develop into once they are injected. As where they actually end up in the organism is difficult to control. While Nakauchi and his team initially want to focus their research only on the pancreas, they commit themselves to immediately discontinuing the experiment, if they discover that more than 30 percent of the cells in the animal’s brain are of human origin. This is also part of the political conditions to prevent the development of an animal that is too „humanized“.

We can see: Philosophers (ethicists) and politicians (decision-makers) will continue to be challenged by technological development.

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