Scientists learn more about how human embryos implant using artificial wombs : NPR

Scientists have gained unprecedented insight into how a human embryo implants in the uterus. They did this by creating a very primitive environment in the laboratory, reminiscent of a womb.

The goal is to help people have healthy babies by finding new clues about the causes of miscarriage and infertility. But the study raises serious ethical issues. It was published Tuesday on three documents in magazines Cell And Cell stem cell.

“This is really important work that advances embryo research – an important step in finding scientific answers to the question of what makes a healthy pregnancy,” says Insoo Hyunbioethicist at the Hastings Center, a bioethics think tank, who was not involved in the study. “However, it also introduces technology that could be used for other purposes of concern.”

This includes the possibility of one day using such technology so that embryos can develop much further – perhaps even entirely – in the laboratory. This process, called ectogenesis, can make a natural human uterus unnecessary.

“This is very worrying,” says Anna Iltisbioethicist at Wake Forest University.

But scientists working on the study say the possibility remains theoretical, and the work could provide important clues about early human development.

“This is very interesting,” says Jun Wumolecular biologist at the University of Texas Southwestern Medical Center who participated in the study.

One of the most important moments in a human embryo's journey to becoming a baby is when a microscopic ball of cells enters the uterus. But this key step in embryonic implantation has long remained a mystery because it occurs hidden inside the body.

“Human implantation is essentially a black box, a mystery,” says Wu. “Implantation occurs very early in pregnancy. Essentially, we don't know when or where. It happens in the womb, which we don’t have access to.”

A look at the causes of miscarriage

In the new study, Wu and his colleagues in China obtained cells and tissue collected from the uterine lining during routine medical procedures and figured out how to recreate a key part of the uterine lining inside tiny plastic devices in their labs.

“You can call it: a womb on a chip,” says Wu.

The scientists then placed human embryos donated for research after fertility treatments, as well as primitive embryo-like creatures created from stem cells – so-called embryoids — inside their tiny wombs on chips and peered through a microscope to see what would happen next.

“This is the first time we have observed the entire sequence of human implantation,” says Wu. “We're very excited about it.”

The researchers have already used their womb-on-chips to discover clues about how embryos and wombs interact, which could “help us understand the implantation process at the molecular level,” Wu says.

The researchers also compared artificial wombs, which used cells from healthy wombs, with artificial uterus using cells from the wombs of women who had miscarriages.

“We saw implantation failure right before our eyes, which is very surprising and exciting,” says Wu.

Wu's team even tested more than 1,100 drugs to see if they could prevent miscarriages, and identified some that looked promising.

A separate group from the UK conducted a similar study in their laboratory in Cambridge.

“We were able to observe some truly fantastic aspects of human embryonic development, many of which had never been observed before,” says Peter Rugg-Gunndevelopmental biologist from the Babraham Institute. “Seeing these events for the first time was fantastic.”

Other scientists welcomed the study.

“This is very interesting,” says Robin Lovell-Badgea developmental biologist at the Francis Crick Institute in London who was not involved in the study. “I think they will provide more information about this absolutely critical stage of human development, which until now has been almost impossible to study.”

An ethical slippery slope?

Among the complex ethical issues raised by the study are questions about the destruction of human embryos for research.

“For those of us who believe that people are human beings and deserve ethical respect, whether they are fetuses, teenagers or the elderly, these experiments are unethical,” the doctor says. Daniel Salmasibioethicist at Georgetown University.

The experiments also raise questions about the use of these devices to study human embryos after 14 days of development, which is considered prohibited in many places. (The researchers did not use their own devices for this.)

There are also concerns about implanting even primitive models of embryos created from stem cells into anything resembling a human uterus.

“Some may be concerned about how far this might go,” says Huhn, a bioethicist at the Hastings Center. “Scientifically, it’s a bit of a slippery slope.”

Indeed, some bioethicists are very concerned about how far this might go.

“This study could contribute to future efforts to support not only early embryo research, but also the growing of embryos for significant periods of time in laboratories, perhaps eventually to embryos,” says Iltis, a bioethicist at Wake Forest University.

If this ever becomes possible, it would open up the prospect of producing human embryos as “spare parts,” Iltis says. “They can be grown as sources of organs and tissues for transplantation. This is very worrying.”

The researchers doing the work say their research is far from that and has no plans to continue it.

“Development entirely outside the uterus is science fiction,” Wu says. “I don't think we're close to that.”

But Iltis claims that other scientists much larger artificial wombs are already being tested to save very premature babies. What sounds like science fiction today may become a reality much sooner than many people think.

“We have a long history of, ‘Don’t worry. There is no science here. This is not the goal. That's not what we're trying to do.” And then he is shown a breakthrough, which signals that the train has left the station.”

“I don’t think it’s far-fetched to think that it will eventually be possible to create laboratory tissues and organs with something like this technology.”