Half-human kidneys grown in a pig


By John

Half-human kidneys were grown in a pig: Previous experiments have managed to generate human tissue such as blood or muscle, but this is the first time that a “humanized” organ has managed to develop within another species.

The result, published in the magazine Cell Stem Cell, was possible thanks to chimera embryos, which contained both pig cells and human cells, generated in the laboratory and then transferred to animals that acted as surrogate mothers. The study, led by the Chinese Academy of Sciences, could lead to a technology for the transplantation of human organs in the distant future, but in the meantime it could be useful for better understanding the development of human organs and in drug testing. “It is an important step forward which opens up interesting perspectives,” Gianluca Amadei, researcher at the University of Padua, told ANSA.

«This is a first feasibility test that is clearly not perfect, but the fact that a way has been found for human cells to survive represents a success. It would now be interesting to understand the differences between these organs and human ones – continues Amadei – and what their properties and characteristics are when development continues”. Researchers coordinated by Liangxue Lai, using the Crispr technique, the “molecular scissors” of DNA, modified pig embryos made up of a single cell by eliminating two genes responsible for the development of the kidneys. Even human embryonic cells, obtained from stem cells, have been modified, inserting genes that instead promote proliferation and avoid self-destruction.

“These are two important steps – explains the Italian researcher – because otherwise human cells are unable to compete against porcine cells inside a pig embryo”. Finally, the chimera embryos were initially grown in the laboratory, in order to provide optimal conditions for both human and pig cells, which have different needs. Once transferred to the surrogate mothers, the embryos were extracted after 25 or 28 days to evaluate their development. The data obtained from five chimera embryos showed correctly developed kidneys, composed of 50-60% human cells, while the rest of the embryo was made up almost entirely of porcine cells. The researchers “found some human cells in the part that gives rise to the nervous system – says Amadei – but none in the part that forms the reproductive system”.

According to the authors of the study, the next step is now to allow the kidneys to develop further and to try a similar approach with other organs, such as the pancreas and heart. The long-term goal is to optimize this technique for human organ transplantation, but the researchers recognize that this is complex work and could take many years: growing a fully functional humanized organ in a pig would take several years. additional steps, because organs are composed of multiple cell and tissue types.