Researchers created the world’s first “synthetic embryos” in a revolutionary feat that bypassed the need for sperm, eggs and fertilization.
Scientists from the Weizmann Institute of Israel found that mouse stem cells could be coaxed into self-assembling into early embryo-like structures with an intestinal tract, the beginnings of a brain, and a beating heart.
Known as synthetic embryos because they are created without fertilized eggs, the living structures should, in the short term, provide a better understanding of how organs and tissues form during the development of natural embryos.
But the researchers believe that this work could also reduce animal testing and ultimately pave the way for new sources of cells and tissues for human transplantation. For example, skin cells from a patient with leukemia could potentially be turned into bone marrow stem cells to treat their condition.
“Remarkably, we show that embryonic stem cells generate whole synthetic embryos, which means this includes the placenta and the yolk sac surrounding the embryo,” said Professor Jacob Hanna, who led the effort. “We are really excited about this work and its implications.” The work is posted in Cell.
Last year, the same team described how they built a mechanical womb that allowed natural mouse embryos to grow outside the uterus for several days. In the latest work, the same device was used to feed mouse stem cells for more than a week, almost half the gestation time of a mouse.
Some of the cells were pretreated with chemicals, which activated genetic programs to develop into a placenta or yolk sac, while others grew unmediated into organs and other tissues.
While most stem cells failed to form embryo-like structures, about 0.5% combined into little balls that developed into separate tissues and organs. Compared to natural mouse embryos, the synthetic embryos were 95% the same in terms of internal structure and genetic profiles of the cells. As far as scientists could tell, the organs that formed were functional.
Hanna said the synthetic embryos weren’t ‘real’ embryos and didn’t have the potential to develop into live animals, or at least they didn’t when they were transplanted into her womb. female mice. He founded a company called Organic renewal which aims to grow synthetic human embryos to provide tissues and cells for medical conditions.
“In Israel and many other countries, like the US and UK, it’s legal and we have ethical approval to do it with human-induced pluripotent stem cells. This provides an ethical and technical alternative to using embryos,” Hanna said.
Dr James Briscoe, senior group leader at the Francis Crick Institute in London, who was not involved in the research, said it was important to discuss how best to regulate labor before synthetic embryos are developed humans.
“Synthetic human embryos are not an immediate prospect. We know less about human embryos than about mouse embryos and the inefficiency of synthetic mouse embryos suggests that translating the findings into humans requires further development,” Briscoe said.
But, he added, “Now is the time to consider the best legal and ethical framework to regulate research and use of synthetic human embryos and to update current regulations.”
Talk to StatNewsProfessor Paul Tesar, a geneticist at Case Western Reserve University, said the further scientists pushed stem cell-derived embryos further down the developmental pathway, the more synthetic and natural embryos began to fuse together.
“There will always be a gray area,” he said. “But as scientists and as a society, we need to come together to decide where the line is and define what is ethically acceptable.”
The creation of “synthetic” human embryos falls outside the legal scope of UK human fertilization and embryology law, but it would be illegal to use them to establish a pregnancy in a woman, as they are not classified as “embryos”. allowed”.