First synthetic models of human embryos are created by scientists

A team of US and UK researchers claims to have created the world’s first synthetic structures resembling human embryos from stem cells, bypassing the need for eggs and sperm.

These embryonic structures are in the earliest stages of human development: for example, they lack a heart or brain. But scientists say they might one day help better understand genetic diseases or the causes of miscarriages.

The research raises vital legal and ethical questions, and many countries, including the United States, lack laws regulating the creation or processing of synthetic embryos.

The pace of discoveries in this field and the growing sophistication of these models have alarmed bioethicists who are getting ever closer to the edge of life.

“Unlike in vitro fertilization (IVF) human embryos, where there is an established legal framework, there is currently no clear regulation governing stem cell-derived human embryo models.”

“There is an urgent need for regulations that establish a framework for the creation and use of stem cell-derived models of human embryos,” said James Briscoe, associate director of research at the Francis Crick Institute.

Dr. Magdalena Zernicka-Goetz described the work in a presentation Wednesday at the annual meeting of the International Society for Stem Cell Research in Boston.

Zernicka-Goetz, Professor of Biology and Biological Engineering at CalTech and the University of Cambridge, explained that the research has been accepted into a prestigious scientific journal but has yet to be published. The study was first published by The Guardian.

Zernicka-Goetz and her team, along with another from Israel, previously described creating embryo-like structures from mouse stem cells. These “embryos” showed the beginnings of a brain, a heart and an intestinal tract after about eight days of development.

The embryonic structures that Zernicka-Goetz says her lab created were grown from individual human embryonic stem cells that were forced to develop into three distinct layers of tissue. They include cells that would normally develop a yolk sac, a placenta, and the embryo itself.

Zernicka-Goetz explained to CNN that the embryonic structures created by his lab are the first to have germ cells that will develop into eggs and sperm.

“I just want to emphasize that these are not human embryos,” Zernicka-Goetz said. “They are embryo models, but they are very interesting because they look so much like human embryos and they are a very important way to find out why so many pregnancies fail, as most pregnancies fail at the time of development, when we build these human-like structures. embryos”.

She said that, to her knowledge, it was the first time a human model embryo had been created with three layers of tissue. But she emphasized that while it mimics some of the characteristics of a natural embryo, it doesn’t have all of them.

The researchers hope these embryo models will shed light on the “black box” of human development, the 14-day period after fertilization, which is the agreed-upon limit for scientists to grow and study embryos in the laboratory.

At the moment, synthetic models of human embryos are confined to test tubes. It would be illegal to implant one in the womb, and animal research using stem cells from mice and monkeys has shown that even when scientists tried to implant them, they didn’t survive, likely because researchers still haven’t figured out how to fully replicate the conditions of pregnancy.

Zernicka-Goetz explained that the goal of her research was not to create life, but to prevent its loss, understanding why embryos sometimes fail to develop after fertilization and implantation.

“We know very little about this stage of human development, but it is a time when many pregnancies are lost, particularly to IVF,” says Roger Sturmey, senior research fellow in maternal and fetal health at the University of Manchester, UK.

“Today, we can say that these ‘synthetic embryos’ share several characteristics with blastocysts, but it is important to recognize that the way synthetic embryos form is different from what happens when a normal embryo forms a blastocyst,” he said.

“There is still a lot of work to be done to determine the similarities and differences between synthetic embryos and embryos that form from the union of an egg and sperm.”

*With information from CNN

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