A team of scientists from the US, China and elsewhere has, for the first time in history, developed embryos that are a mixture of human and apse cells.
The embryos, outlined Thursday in the scientific journal Cell, were created for scientists to discover new ways to produce organs for people in need of transplants.
The researchers injected 25 human stem cells, known as induced pluripotent stem cells (or ISP cells), into embryos of macaque capes. The scientists cultured the mixed embryos for up to 20 days in test tubes to study how the animal and human cells communicate with each other.
The idea behind the research is to determine whether monkeys can eventually grow human organs for transplants. According to the team of scientists, thousands of people die every year and wait for such transplants.
Over the past few years, some scientists have been experimenting with injecting human stem cells into sheep and pig embryos to see if it can grow human organs. However, according to NPR, it has been unsuccessful so far.
Now the team of scientists has chosen to experiment with monkeys because they are genetically much more closely related to humans. The researchers reported that after one day, they were able to detect human cells growing in 132 of the injected embryos.
However, most of the embryos died during the 20-day experiment, and those that survived retained only 4 to 7 percent of human cells, according to the South China Morning Post. Nevertheless, the scientists found that the research represented significant progress for this type of study.
“This knowledge will enable us to go back now and try to design these pathways that are successful in enabling the appropriate development of human cells in these other animals,” said Juan Carlos Izpisua Belmonte, a professor of genes Expression Laboratory of the Salk Institute. for biological sciences in La Jolla, California, told NPR. “We are very, very excited.”
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This type of mixed species embryo is known as chimeras, named after a fire-breathing creature from Greek mythology that is part lion, part goat and part snake.
Although the researchers believe the work is an important thing, other scientists have expressed concern that the experiment may be unethical. One concern is that someone could eventually try to take this research a step further and create a baby out of a mixed embryo.
“Nobody really wants monkeys roaming around with human eggs and human sperm,” said Hank Greely, a Stanford University bioethicist who co-authored an article in the same issue of the magazine criticizing the research line, while noting that this particular study was done ethically, according to NPR.
“Because when a monkey with human sperm meets a monkey with human eggs, no one wants a human embryo in the womb of a monkey,” Greely added.
Kirstin Matthews, a fellow in science and technology at the Baker Institute of Rice University, told the news office that it would become an ethical issue if human cells became part of the developing brain of such a mixed embryo.
“Should it be regulated as a human because it contains a significant proportion of human cells? Or should it just be regulated as an animal? Or something else?” Matthews said. “At what point do you take something and use it for organs when it actually starts thinking and has logic?”
“I think the public is going to be worried, and I’m also like that we just want to move forward with science without having a proper conversation about what we should do or not,” she added.
The study’s lead author, Tan Tao of Kunming University of Science and Technology, defended the research on Friday, saying the study ‘was not a work of bad taste, but [one] of very practical value, “according to the Post.
“Our goal is not to generate any new organism, no sample,” Belmonte told NPR. “And we do not do such a thing. We try to understand how cells of different organisms communicate with each other.”
Newsweek contacted the lead author of the study for additional comment, but did not hear in time for publication.