Artificial Embryos Created in Lab
Scientists at the University of Cambridge have managed to create a structure resembling a mouse embryo in culture, using two types of stem cells and a 3D scaffold on which they can grow.
At the blastocyst stage, the stem cells that will eventually make the body, the embryonic stem cells (ESCs), cluster together inside the embryo towards one end. The other two types of stem cell in the blastocyst are the extra-embryonic trophoblast stem cells (TSCs), which will form the placenta; and primitive endoderm stem cells that will form the so-called yolk sac, ensuring that the organs develop properly and providing essential nutrients.
Previous attempts to grow embryo-like structures using only ESCs have had limited success. This is because early embryo development requires the different types of cell to coordinate closely with each other. The Cambridge team, whose work is published in the journal Science, created their artificial embryo using ESCs and TSCs.
Lead researcher Prof Magdalena Zenricka Goetz said: “We knew that interactions between the different types of stem cell are important for development, but the striking thing that our new work illustrates is that this is a real partnership—these cells truly guide each other.”
Prof Goetz’s team has already grown these artificial mouse embryos to 14 days, the legal limit for growing human embryos in the lab, and they are now working on using the same technique to develop artificial human embryos. The researchers hope their work will help improve fertility treatments. It could also provide useful insights into the way early embryos develop.
While this artificial embryo closely resembles the real thing, it is unlikely that it would develop further into a healthy foetus, say the researchers. To do so, it would likely need the third form of stem cell, which would allow the development of the yolk sac, which provides nourishment for the embryo and within which a network of blood vessel develops. In addition, the system has not been optimised for the correct development of the placenta.
Prof Jonathan Montgomery, an expert in health care law, at University College London, suggested that the “artificial” human embryos may not be subject to the same legal restrictions as normal human embryos. “It wouldn’t, obviously, be within the current regulatory framework, although we would need to think carefully about how we should oversee it,” he said.
BBC. March 3. Science Daily. March 2. Science. March 1.