Artificial embryo grown in the laboratory for the first time

synthetic embryo

A man-made embryo has been created in a laboratory for the first time in the world, raising hopes for preventing miscarriages.

An embryo normally requires fertilization of an egg with a sperm, and the sperm then grows in the uterus before birth.

Now, scientists at the Weizmann Institute of Science in Israel have shown that a synthetic version can be created using nothing but mouse stem cells, without conception.

They formed a beating heart, a brain and an intestinal tract much like a natural embryo, the researchers found.

The experiment opens the door to new forms of research into fetal development and miscarriages, as well as a potential way to scale back animal experiments. In the future, the technique will also be able to grow embryos as a stock of organs for harvesting and transplantation.

In 2021, the team created a way to produce “naive” stem cells that have the ability to transform into any tissue in the body, from neurons to skin cells. They also built a machine that works like an artificial uterus and allows embryos to grow normally.

But previous studies had worked with eggs from real mice that had been fertilized, and the team wanted to create synthetic alternatives, bypassing entirely natural steps.

The versatile stem cells from naive mice were put into the machine, combining both previous findings with chemicals to aid the development of the placenta and yolk sac, essential for embryonic development.

fetal develop

fetal develop

Professor Jacob Hanna of Weizmann’s Department of Molecular Genetics, who led the research team, called the chemicals “a transient boost” to help support development.

The overwhelming majority of experiments failed, but for 0.5 percent of the attempts, one in 200, a progenital embryonic sphere formed.

This minority of experiments then stretched on and lasted more than eight days, growing in exactly the same way and at the same rate as a natural embryo.

A mouse pregnancy lasts just 20 days, so 8.5-day-old embryos have already developed miniature, functioning organs, including a beating heart, a brain and an intestinal tract.

The researchers labeled the cells with colored tags so they could be seen under a microscope and saw that the synthetic embryo, made up of no sex cells, was 95% similar to a real mouse fetus.

Professor Hanna said the team now wants to find out exactly how cells know what to do and how instructions are relayed to produce organs in the right place at the right time.

He added that because the team’s mechanical approach to the uterus and Petri dish is transparent, they can track each stage of an embryo’s development in extreme detail.

This, he says, “may be useful for modeling birth defects and implantation of human embryos” to shed light on the hidden dynamics of embryonic development, which may help explain the cause of some miscarriages.

transparent uterus

transparent uterus

And since the system only needs stem cells, not actual fertilized eggs, the supply is vast and there are fewer logistical and ethical obstacles in the way of research.

Embryos are not real, Professor Hanna said, and if left to grow to completion they would not produce live animals.

Israel, where the work was carried out, has ethical approval for these experiments to be done with human stem cells. The UK has similar laws, and this could open the door to such research, where synthetic human embryos are developed in the lab for study, experimentation, and ultimately transplantation.

The researchers say the discovery is a significant advance for research, but add that there is still a long way to go to improve the technique.

Professor Alfonso Martinez Arias of the Universitat Pompeu Fabra (UPF) in Barcelona called the findings “a potentially significant development” but said the reliability of the process must be improved as a priority before it can be widely employed.

“It will take time, but it will be done,” he added.

“Importantly, this opens the door for similar studies with human cells, although there are many regulatory hurdles to get through first.”

James Briscoe, assistant director of research at the Francis Crick Institute in London, said synthetic human embryos were still a distant dream, but said the work was “a valuable proof of concept.”

Leave a Reply

Your email address will not be published.