Japan’s Asahi Shimbun newspaper has reported that a proposal submitted by the researchers at the University of Tokyo to create animal embryos with human cells and to implant them into a surrogate animal to be brought to term has been given provincial approval by Japan’s science ministry.
According to UCLA’s Broad Stem Cell Research Center, the group tries to create a human pancreas inside rodents using human pluripotent stem cells – a type of undifferentiated stem cell that has the ability to develop into any living tissue.
The researchers will take fertilized eggs from rodents and edit the sequences in the genome that would transcribe rodent pancreas and instead insert human pluripotent cells that would enable it to develop human pancreas, which will subsequently be implanted into a surrogate animal, enabling the hybrid embryo to come to term.
Hiromitsu Nakauchi, a researcher at the Institute of Medical Science of the University of Tokyo is quite exuberant that they can start serious studies in the field which would enable researchers to create organs in the rodents, which can then be transplanted into humans.
Asahi reported that the organs created in this manner cannot be viable for human transplant immediately but to advance their research with the data they have collected hitherto.
The government relaxed its laws against a previous moratorium on such experiments and has said the experiments can continue as long as a creature is not born that’s a chimera of a human and an animal.
Japan is the first country to have allowed human-animal hybrids to come to full term and if the researchers find in the brains of the hybrid animal that has come to term, more than 30% of human cells, they will immediately terminate the experiment.
Jun Wu, a biologist at the Salk Institute in La Jolla, California has reckoned that only 1 in 100,000 cells in these hybrids were human.
Elsewhere, in the US, human-pig hybrids were studied in the lab and were allowed to grow for three or four weeks before destroying them, as per the ethics regulation in the US.
Also there has been research done in the UK at King’s College, London, Newcastle University and Warwick University apropos of hybrid embryos to create embryonic stem cells that could potentially treat a plethora of diseases.
What about the ethical concerns for this type of study?
Jiro Nudeshima, a researcher specializing in the ethical implications of life science research looks askance at the procedure as the human cells that are implanted into the fertilized eggs of rodents can behave capriciously which could have harmful effects on the animal’s health.
Nakauchi, the lead researcher has dismissed these concerns are extraneous as their experiments focus on targeted organ development and not in spawning a new species.
He also expressed confidence in the procedure as in previous attempts, the number of human cells compared to the number of sheep cells in the hybrid embryo is negligible, in the range of one in a myriad and emphasized that the procedure will not create an animal with a human face.