Researchers have created the world’s first “artificial embryos”. This is a groundbreaking achievement that goes beyond the need for sperm, eggs and fertilization. Scientists at the Weizmann Institute in Israel have discovered that rat stem cells can self-assemble into early embryo-like structures with the intestinal tract, the beginning of a brain and a beating heart.
The living structures, called artificial embryos because they come without fertilized eggs, are expected in the short term to lead to a better understanding of how organs and tissues form during normal embryo development.
But the researchers believe the work could also reduce animal testing and eventually pave the way for new sources of cells and tissues for human cultivation. For example, skin cells from a leukemia patient can be converted into bone marrow stem cells to treat their condition.
Professor Jacob Hanna, who led the work, said: “Remarkably, we show that embryonic stem cells generate fully artificial embryos, including the placenta and yolk sac surrounding the embryo.” “We are really excited about this work and its implications.”
Last year, the same team described how they built a mechanical uterus that allowed normal mouse embryos to grow outside the womb for several days. In recent work, the same device was used to feed mouse stem cells for over a week, roughly half the mouse’s gestation period.
Some cells were pre-treated with chemicals, creating genetic programs to transform into a placenta or yolk sac, while others developed into other organs and tissues without interference.
Most stem cells failed to form embryonic structures, but about 0.5% grew into small globules forming separate tissues and organs. Compared with normal rat embryos, the artificial embryos were 95% similar in their internal structure and genetic profiles of the cells. As far as scientists can determine, the organs formed were functional.
Hanna said the artificial embryos are not “real” embryos and do not have the ability to develop into living animals, at least not when implanted in the wombs of female mice. He founded a company called Renewal Bio that aims to grow artificial human embryos to provide tissues and cells for medical conditions.
“In Israel and many other countries, such as the United States and the United Kingdom, it is legal and we have ethical approval to do so with human-induced pluripotent stem cells. This provides an ethical and technical alternative to using embryos,” Hanna said.
Dr James Briscoe, group leader at the Francis Crick Institute in London, who was not involved in the study, said it was important to discuss how best to organize labor before developing artificial human embryos. Artificial human embryos are not an immediate possibility. We know less about human embryos than we do about mouse embryos, and the inefficiency of artificial mouse embryos suggests that translation of the results to humans requires further development.”
But he added: “Now is the time to consider the best legal and ethical framework to regulate the research and use of human artificial embryos and update existing regulations.”
Speaking to StatNews, Professor Paul Tessar, a geneticist at Case Western Reserve University, said that the more scientists develop this technique, the sooner the artificial and natural embryos will begin to fuse together. “There will always be a gray area,” he said. “But as scientists and as a society, we have to decide together where the limits lie and define what is morally acceptable.”
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