Chinese scientists have managed to grow kidneys containing human cells in pig embryos, which for the first time in the world raises ethical questions and may offer new ways to solve the problem of the shortage of organ donors, reports AFP.

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 Medical Sciences focused on kidneys, which are among the first organs to develop and are most often transplanted into humans.

While researchers in the United States have recently succeeded in transplanting genetically modified pig kidneys and even a human heart, Chinese scientists have taken a different approach, trying to grow a kidney in a pig embryo that is as close as possible to an embryonic pig kidney. man.

“Rat organs have already been grown in mice, and mouse organs have been grown in rats, but previous attempts to grow human organs in pigs have failed,” Lianxue Lai, one of the study’s lead authors, said in a press release.

“Our approach allowed better integration of human cells into recipient tissues and allows us to grow human organs in pigs,” he adds.

For Dushko Ilic, a stem cell specialist at King’s College London, this study “describes the early stages of a new approach to organ bioengineering, using pigs as an incubator for growing human organs.”

In addition to the ethical issues, there are still many challenges to overcome before this experiment can provide a viable solution to the shortage of donor organs, “but it is still an exciting strategy that deserves further research,” adds the expert. participates in a Chinese study.

Genetic “niche”…

One of the main challenges in creating such hybrids is that pig cells must compete with human cells. To overcome this obstacle, the team from the Guangzhou Institute used a new genome-editing tool called CRISPR, which allowed them to cut DNA at a specific point.

Specifically, they cut out two genes associated with kidney growth in pig embryos to create what they call a “niche.” Then they added human pluripotent stem cells, that is, cells capable of turning into any type of cell.

In total, the researchers transplanted 1,820 embryos into 13 surrogate “mothers” and terminated their pregnancies after 25-28 days to see if the experiment was successful.

Five embryos selected for analysis had functional kidneys for this stage of development and were beginning to develop the urethra that would eventually connect the kidneys to the bladder.

And they make up from 50% to 60% of human cells, the researchers concluded.

“We found that by creating a niche in the pig embryo, it allowed human cells to naturally take their place,” said study co-author Zhen Dai, adding that human cells were found in the pig’s spinal cord and brain.

Although no human cells have been found in the genital organs of pigs, their presence outside the kidneys and, in particular, in the brain raises ethical questions about the hybrid creatures, says Darius Widera, professor of molecular biology at the University of Reading.

“Although this approach is a new step in research and the first successful attempt to grow organs containing human cells in pigs, the proportion of human cells in the created kidneys is still not very high,” he added.