Scientists at the University of Exeter's Living Systems Institute, in collaboration with colleagues from the University of Cambridge, have developed a method to organise lab-grown stem cells into a model of a blastocyst to recreate the first stage of human embryo development.
Professor Austin Smith, director of the Living Systems Institute, said: 'Finding that stem cells can create all the elements of an early embryo is a revelation. This is quite remarkable and unlocks exciting possibilities for learning about the human embryo.'
Presently, natural human embryos are not readily available for research. There is a legal ban on creating or culturing them in the laboratory beyond 14 days, known as the '14-day rule' (see BioNews 1083). This has greatly limited researchers' ability to learn and understand the earliest biological beginnings of humans. To date, researchers have relied upon limited human embryo donations or animal models, primarily mice.
Published in Cell Stem Cell, the team showed how they arranged the stem cells into clusters and briefly introduced two molecules known to influence cells in early development. They found that 80 percent of the clusters organised themselves after three days into structures that look curiously like the blastocyst stage of an embryo – a ball of around 200 cells formed from the fertilised egg after six days. The team further showed that these curious clusters have the same active genes as a natural embryo.
The study, directed by Dr Ge Guo, also from the University of Exeter's Living Systems Institute, said the new technique provides 'for the first time, a reliable system to study early development in humans without using embryos'.
This method has the potential to be used by researchers from around the world to investigate the early stages of development, which to date has not been possible.
The next step for the researchers is to understand how to develop the artificial blastocysts beyond the early stage, and to study the critical period when an embryo implants into the womb and how it stays implanted. Miscarriage occurs in approximately one in eight pregnancies, of which three in every four happen during the first 12 weeks.
In addition, the authors have speculated that it may lead to a better understanding of embryo development and help the approximate one in seven couples who suffer from infertility.