Scientists succeeded in creating an experiment that may make you feel in a science fiction movie. They created the first two human-pig embryos. However, they destroyed them afterwards.
The experiment was made up of human stem cells that were grown inside pig embryos. The human cells were only a small part of the embryos. The main purpose of this controversial experiment was to see if such combinations can create replacement organs for humans that would not be rejected in transplants.
The experiment was conducted by scientists in both California and Spain and was funded by private companies and foundations. The private funding was necessary after the U.S. no longer allowed that taxpayer money should be used for human-animal experiments.
Juan Carlos Izpisua Belmonte, researcher at the Salk Institute in California, is one of the scientists involved in the experiment. He declared that the reality of having human organs grown inside pig embryos is still not possible at the moment. There is a long way until the aim is reached, but this experiment was the first step towards that aim.
As expected, the scientists faced many difficulties. The developmental progresses of each species are different and they might not be perfectly compatible. This makes it difficult to mix cells of two different species, especially when there is a longer evolutionary distance between them.
Animals that contain the cells of two species are called chimeras. Such animals have been successfully created with both rat and mouse cells, but larger animals are required to grow human organs, hence the choice of pigs.
This experiment would be of immense help for people who need transplants and find no human donor available. Every 10 minutes, an ill person gets on a waiting list for organ transplants and about 22 people die every die while waiting for someone to donate them an organ.
The researchers are planning to develop human pancreases, heart, and livers inside pigs. After these organs are grown in the place of pig organs, the animals are to be euthanized. As expected, the experiment raised many ethical concerns, for example the fear of an animal developing human characteristics.
Despite the controversy, the human-pig embryos are a huge discovery that can strike the medical world and find a permanent solution to transplants. Many lives can be saved and medicine can reach a new era.
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