Scientists have created an artificial mouse embryo from stem cells for the first time.
The breakthrough, which could shed light on why two-thirds of human pregnancies fail in the early stages of embryo development, was made by researchers at the University of Cambridge.
Using two types of stem cells – embryonic (ESCs) and trophoblast (TSCs) – with a 3D scaffold, the scientists grew a structure capable of assembling itself.
The artificial structure’s development and architecture closely resembled that of a natural embryo.
When a mammalian egg is fertilised by a sperm, it divides to create a ball of stem cells. The ESCs cluster together at one end of the embryo, while the TSCs form a placenta.
A third type of stem cell – primitive endoderm – form a yolk sac which provides essential nutrients for the foetus’s organs to develop properly.
Early embryo development requires the different cells to co-ordinate closely with each other, and previous attempts to create an artificial structure using only ESCs have been unsuccessful.
But the research, published in the journal Science on Thursday, found that the two types of cell communicate about where in the embryo to place themselves.
Professor Magdalena Zernicka-Goetz, who led the research, 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.
“Without this partnership, the correct development of shape and form and the timely activity of key biological mechanisms doesn’t take place properly.”
The artificial embryo, while akin to a natural one, is unlikely to grow to a healthy foetus because it would need the third stem cell to create the yolk sac.
However, the study could help scientists understand the developmental events that occur before a human embryo reaches 14 days.
“We are very optimistic that this will allow us to study key events of this critical stage of human development without actually having to work on embryos,” Prof Zernicka-Goetz said.
“Knowing how development normally occurs will allow us to understand why it so often goes wrong.”