Scientists create world’s first ‘synthetic embryos’

The world's first synthetic embryo was created without sperm, eggs or fertilisation.

Scientists at the Weizmann Institute in Israel found that stem cells from mice could be used to create structures similar to an embryo.

Synthetic embryos are created without fertilised eggs and are known as living structures to drive deeper understanding of how organs and tissues form.

Researchers believe that the work could lead to new sources of cells and tissues for human transplant. Skin cells from a leukaemia patient can be turned into bone marrow stem cells.

Prof Jacob Hanna, who led the effort, said, "Remarkably, we show that embryonic stem cells generate whole synthetic embryos, meaning this includes the placenta and yolk sac." This work and its implications are exciting to us. The work is in a journal.

A year ago, the same team described how they built a mechanical womb that allowed mouse embryo to grow outside the uterus for several days. The same device was used to nurture mouse stem cells for more than a week, half the time it takes for a mouse to develop.

Some of the cells were pre-treated with chemicals, which switched on genetic programmes to develop into organs and other tissues.

The stem cells combined into little balls that grew different tissues and organs. The synthetic embryo was the same in structure and genetics as the natural one. The scientists were able to tell that the organs were functioning.

When synthetic embryos were put into the wombs of female mice, they didn't have the ability to develop into live animals. A company called Renewal Bio was founded by him to grow human synthetic embryos to provide tissues and cells for medical conditions.

It is legal in Israel, the US and the UK, and we have ethical approval to do it. The use of embryos is not being provided an ethical and technical alternative.

The Francis Crick Institute's principal group leader, who was not involved in the research, said that it was important to discuss how best to regulate the work before human synthetic embryos were created.

There isn't an immediate prospect for synthetic human embryos. The inefficiency of the mouse synthetic embryo suggests that it takes further development to translate the findings to humans.

He said that now is a good time to consider the best legal and ethical framework to regulate research and use of human synthetic embryos.

Prof Paul Tesar, a geneticist at Case Western Reserve University, told StatNews that more scientists push stem cell-derived embryos further along the path of development.

He said there would be a grey area. As scientists and as a society, we need to define what is morally acceptable.

The creation of synthetic human embryos is outside of the legal framework of the UK's Human Fertilisation and Embryology Act, but it would be illegal to use them to create a pregnant woman.