By Kate Kelland
LONDON (Reuters) - Scientists in Britain have for the first time created a structure that resembles a mouse embryo using a 3D scaffold and two types of stem cells - research which deepens understanding of the earliest stages of mammalian development.
Publishing their results in the journal Science on Thursday, the team based at Cambridge University said that while the artificial embryo closely resembled the real thing, it would be unlikely to develop further into a healthy mouse fetus.
For research purposes, however, the scientists were able to show how the artificial embryo followed the same pattern of development as a normal embryo - with the stem cells organizing themselves in the same way.
Magdalena Zernicka-Goetz, a professor at Cambridge's department of Physiology, Development and Neuroscience who led the work, said the success with mouse cells should pave the way for similar work with human cells, helping scientists overcome a major barrier to human embryo research - a shortage of embryos.
Currently, human embryos for research are developed from surplus eggs donated through fertility clinics, but Zernicka-Goetz said it should in future be possible to use the stem cells and scaffold technique to make artificial human embryos for study.
"This will allow us to study key events of this critical stage of human development without actually having to work on embryos," she said. "(And) knowing how development normally occurs will allow us to understand why it so often goes wrong."
Previous attempts to grow embryo-like structures have not had much success. The Cambridge team said they now think this was because these experiments used only one type of stem cells - embryonic stem cells (ESCs) - and did not allow for the fact that early embryo development requires different types of cell to coordinate closely with each other.
For this work, Zernicka-Goetz's team used ESCs plus another type called extra-embryonic trophoblast stem cells (TSCs).
"Both the embryonic and extra-embryonic cells start to talk to each other and become organized into a structure that looks like and behaves like an embryo," Zernicka-Goetz said.
Stem cell specialists not directly involved in the work praised its methods and said the results would prove valuable in deepening scientific understanding of embryonic development.
Dusko Ilic, a reader in stem cell science at King's College London, described it as a "masterpiece" and "a beautifully conceived and executed study demonstrating interplay of different cells in different cellular compartments within the first days of mouse development".
(Editing by Catherine Evans)