Embryo research is legally, ethically and technically fraught. But there is now a rapidly developing field mimicking natural embryo development.
This research, published in the journal Nature, is described by the Israeli team as the first “complete” embryo model for mimicking all the key structures that emerge in the early embryo.
“This is really a textbook image of a human day-14 embryo,” Prof Hanna says, which “hasn’t been done before”.
Instead of a sperm and egg, the starting material was naive stem cells which were reprogrammed to gain the potential to become any type of tissue in the body.
Chemicals were then used to coax these stem cells into becoming four types of cell found in the earliest stages of the human embryo:
epiblast cells, which become the embryo proper (or foetus)
trophoblast cells, which become the placenta
hypoblast cells, which become the supportive yolk sac
extraembryonic mesoderm cells
A total of 120 of these cells were mixed in a precise ratio – and then, the scientists step back and watch.
🔬 Scientists have developed human embryo-like structures without using sperm, an egg or fertilisation, offering hope for research on miscarriage and birth defects but also raising fresh ethical concerns. ➡️ https://t.co/GYPPkJTf1Dpic.twitter.com/dtJ74tIDoi
BBC also discussed legal and ethical concerns of this demonic research that should cease to exist.
The work also raises the question of whether embryo development could be mimicked past the 14-day stage.
This would not be illegal, even in the UK, as embryo models are legally distinct from embryos.
“Some will welcome this – but others won’t like it,” Prof Lovell-Badge says.
And the closer these models come to an actual embryo, the more ethical questions they raise.
They are not normal human embryos, they’re embryo models, but they’re very close to them.
“So should you regulate them in the same way as a normal human embryo or can you be a bit more relaxed about how they’re treated?”
Prof Alfonso Martinez Arias, from the department of experimental and health sciences at Pompeu Fabra University, said it was “a most important piece of research”.
“The work has, for the first time, achieved a faithful construction of the complete structure [of a human embryo] from stem cells” in the lab, “thus opening the door for studies of the events that lead to the formation of the human body plan,” he said.
The researchers stress it would be unethical, illegal and actually impossible to achieve a pregnancy using these embryo models – assembling the 120 cells together goes beyond the point an embryo could successfully implant into the lining of the womb.