Scientists have used stem cells to create structures resembling human embryos for the first time in the lab, leading to calls for tighter regulation of the rapidly growing space. Many different labs around the world have published prepress studies describing their research in the past seven days, and experts say it should be treated with caution, as the research has not yet undergone peer review.

The labs used a variety of techniques to induce human embryonic stem cells, which can be any type of cell, to spontaneously assemble into an embryo-like structure without the need for sperm, eggs, or fertilization. The goal is to give scientists a model to study human embryos in a way never before possible due to ethical concerns, in hopes of gaining new insights into the causes of birth defects, genetic disorders, infertility and other problems during pregnancy.

The first announcement was made last Wednesday when Magdalena Zernichka-Goetz of the University of Cambridge and Caltech Institute described her team’s work at the International Society for Stem Cell Research annual meeting in Boston. On Thursday, Jacob Hanna’s team at the Weizmann Institute of Science in Israel published a preprint study detailing their own work on stem cell-based models of human embryos.

The Zernicka-Goetz team then quickly published its own preprint, providing more information. Other labs in China and the United States have done the same, releasing preprints last week. The researchers opposed media reports calling the cell clusters “synthetic embryos” and said they were not fully synthetic, were grown from stem cells, and should not be considered embryos.

“Almost unusual”

The data rush has highlighted the highly competitive nature of research in this area. Last August, both Zernicka-Goetz and Hanna’s teams published papers about their work to create the first embryo-like structures using mouse stem cells. Both teams told AFP that their new research has been accepted by prestigious peer-reviewed journals and presented their work at conferences months before recent media attention.

Hannah dismissed the notion that both teams were “firsts”, saying they had very different results. He told AFP that his models had “the placenta, the egg sac, the amniotic cavity,” and other features of an embryo that he said were not found in the Czernytska-Goetz structures.

Other researchers seem to agree that Hanna’s models are more advanced, praising her team for using only chemical modifications, not genetics, to transform cells into embryo-like structures.

“The resemblance of Hannah’s model to a natural embryo is incredible, almost uncanny,” said researcher Jesse Wenvleet of the Max Planck Institute for Molecular Cell Biology and Genetics in Germany. Darius Widera, a stem cell biologist at the University of Reading in England, told AFP it’s best to wait for peer review before comparing studies. But “the impact of both studies is huge,” he added.

“We should try to avoid the unhealthy hype because this technology is in its infancy, but new guidelines will now be needed.”

Is it in the “black box”?

Both labs said they developed their embryo models for 14 days, which is the legal limit for growing human embryos in the lab in many countries. After 14 days, embryos begin to organize cells to form organs, including the brain; This is a period called the “black box” because little is known about human embryos after that point.

Research regulations in this area vary between countries, but most involve fertilized embryos; this is a vacuum through which new embryo-like models are slipping. The University of Cambridge said Friday it has launched a project to develop the UK’s first governing structure for stem cell-based human embryo models.

The scientists emphasized that they have no intention of placing the model embryos in the human womb, and even if they did, it would not result in a baby. An embryo model implanted in a male macaque as part of previous studies showed some signs of pregnancy but did not survive, Wiedera said. James Briscoe of the Francis Crick Institute in England urged researchers to “be cautious, cautious and transparent”.

“Having danger, missteps or false claims having a deterrent effect on the public and politicians is a major setback for the industry.” Source