2023-09-08 13:15:47
It is still far too early to make it a viable solution to the shortage of organ donations. But Chinese scientists have succeeded in developing kidneys containing human cells in pig embryos, a world first which raises ethical questions.
In this study, the results of which were published Thursday in the scientific journal Cell Stem Cell, researchers from the Guangzhou Institute of Biomedical and Health Sciences chose the kidneys because they are both among the first organs to develop and most often transplanted into humans.
“Growing human organs in pigs”
If researchers in the United States have recently succeeded in transplanting genetically modified pig kidneys, or even a heart, into humans, scientists in China have opted for another approach by trying to grow a pig embryo into a pig embryo. kidney as close as possible to that of a human.
“Rat organs had previously been grown in mice, mouse organs in rats, but past attempts to grow human organs in pigs had failed,” Liangxue Lai said in a statement. one of the main authors of the study. “Our approach has improved the integration of human cells into recipient tissues and allows us to grow human organs in pigs,” he adds.
For Dusko Ilic, stem cell specialist at King’s College London, this study “describes the founding steps of a new approach in the bioengineering of organs using pigs as incubators for the growth of human organs”. In addition to ethical issues, there are still many challenges for this experiment to be a viable solution to the shortage of organ donations, “but it is nonetheless a fascinating strategy that deserves to be explored. dug”, adds this specialist who did not participate in this Chinese study.
Convincing results
One of the main challenges in creating such hybrids is that pig cells compete with human ones. To overcome this hurdle, the Canton Institute team used a new genome editing tool called CRISPR that allowed them to cut DNA at a specific location.
In total, the researchers transplanted 1,820 embryos into 13 surrogate mothers and terminated their pregnancies between 25 and 28 days later to see if the experiment was successful or not. However, five of the embryos chosen for analysis had functioning kidneys for this stage of development and were beginning to develop a urethra that would eventually connect the kidneys to the bladder. And they were composed of between 50% and 60% human cells, the researchers concluded.
“We discovered that by creating a niche in the pig embryo, this allowed human cells to naturally take their place,” said Zhen Dai, co-author of the study, adding that human cells had however been found in the spinal cord and brains of pigs.
Ethical questions regarding hybrid creatures
Although no human cells were found in the genitals of the pigs, their presence outside the kidneys, and especially in the brain, raises ethical questions regarding the hybrid creatures, notes Darius Widera, professor of molecular biology at the University of Reading. “Although this approach is a new milestone in research and a successful first attempt to grow organs containing human cells in pigs, the proportion of human cells in the generated kidneys still does not remain very high,” he said. -he adds.
For the time being, the Chinese team admits that it is not ready to transplant one of these kidneys into a human, but it hopes to get there one day by refining its technique. And one of the main problems is that the kidneys produced in this way retain a system of vascular cells inherited from the pig, which risks causing rejection in the event of transplantation of these organs into a human. Besides the kidneys, the Canton Institute team is already working on growing other human organs in pigs such as a pancreas or a heart.
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