In 2017, scientists created the first human-pig hybrid, but found the human cells had poor molecular communication. So they decided to investigate lab-grown chimeras using a more closely related species, macaques.
NILIMA MARSHALL: US scientists have grown human cells in monkey embryos in a bid to understand more about how cells develop and communicate with each other… Researchers from the Salk Institute in California produced what is known as monkey-human chimeras, with human stem cells – special cells that have the ability to develop into many different cell types – inserted in macaque embryos in petri dishes in the lab…
In 2017, Prof Izpisua Belmonte and his team created the first human-pig hybrid, where they incorporated human cells into early-stage pig tissue but found that human cells in this environment had poor molecular communication. So the team decided to investigate lab-grown chimeras using a more closely related species – macaques.
The human-monkey chimeric embryos were monitored in the lab for 19 days before being destroyed. According to the scientists, the results, published in the journal Cell, showed that human stem cells “survived and integrated with better relative efficiency than in the previous experiments in pig tissue”…
But some ethicists in the UK have raised concerns, saying the work “poses significant ethical and legal challenges” and “opens Pandora’s box to human-nonhuman chimeras”. They are calling for a public discussion about the ethical and regulatory challenges associated with human-animal chimeras, organisms whose cells come from two or more individuals…
Commenting on the research, Dr Anna Smajdor, lecturer and researcher in biomedical ethics at the University of East Anglia’s Norwich Medical School, said: “This breakthrough reinforces an increasingly inescapable fact: biological categories are not fixed – they are fluid.
“This poses significant ethical and legal challenges”… She added: “The scientists behind this research state that these chimeric embryos offer new opportunities, because ‘we are unable to conduct certain types of experiments in humans’. “But whether these embryos are human or not is open to question.”
Prof Julian Savulescu, director of the Oxford Uehiro Centre for Practical Ethics and co-director of the Wellcome Centre for Ethics and Humanities, University of Oxford, said: “This research opens Pandora’s box to human-nonhuman chimeras.”
“These embryos were destroyed at 20 days of development but it is only a matter of time before human-nonhuman chimeras are successfully developed, perhaps as a source of organs for humans. That is one of the long-term goals of this research.
“The key ethical question is: what is the moral status of these novel creatures? Before any experiments are performed on live-born chimeras, or their organs extracted, it is essential that their mental capacities and lives are properly assessed.” SOURCE…
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