A team of stem cell researchers in Israel has managed to create the world’s first synthetic embryos from mouse stem cells, a scientific feat that could hold the key to ending animal testing in medical research and offering new solutions to heal people.
The embryos created by scientists at the Weizmann Institute of Science in Rehovot are “synthetic” because their creation did not involve an egg or sperm, or even a mouse uterus.
The mouse stem cells – cells that can develop into any organ or tissue – were grown in an artificial uterus for eight days, where they developed a rudimentary brain, an intestinal tract and a beating heart.
After eight days – the equivalent of three months of pregnancy for a mouse – the embryo stopped growing.
The experiment is yet another success in the race to develop embryos from human and mouse stem cells, which Weizmann Institute scientists said could hold the key to understanding how organs develop in embryos and one day creating replacement organs for them. people who need a transplant.
But the research, published Monday in the journal Cellit also raises ethical questions that make many uncomfortable.
As scientists’ ability to transform stem cells into human organs and even embryos becomes increasingly sophisticated and successful, achieving goals we once thought impossible, do we stop to think about limits?
That was the question the International Society for Stem Cell Research (ISSCR) tried to answer last year when it issued new guidelines limiting the cultivation of human embryos in the laboratory. to 14 days, before the first signs of the nervous system begin to appear. After that, the embryos must be destroyed.
But while there are regulations around human embryos, synthetic human embryos are a new prospect. Could a synthetic human embryo one day be implanted in a person’s uterus?
Scientists at the Weizmann Institute said that synthetic mouse embryos, despite looking a lot like natural mouse embryos, cannot be considered the same, and any attempt to implant them in a mouse’s uterus does not translate into pregnancy.
This suggests that, for the moment, baby mice still need to be raised the old-fashioned way — egg, sperm, and everything that comes with it.
But the research paves the way for the possibility that, one day, baby mice could be created from any mouse cell. And after that, what stops us from creating human embryos outside the womb?
The Weizmann Institute researchers said their only goal in conducting the experiment is to prove whether it will one day be possible to create synthetic embryos capable of producing replacement organs for those in need of transplants.
“Our goal is not to get pregnant outside the womb, whether in mice or any species,” said lead researcher Jacob Hanna, as reported by the Washington Post. “We are really struggling to make organs – and in order for stem cells to become organs, we need to learn how the embryo does that. We started with that because the uterus is a black box – it’s not transparent.”
Hanna created her own company, Renewal Bio, with the aim of growing synthetic human embryos that will provide tissues and cells for transplants and replacements.