Scientific group recommends abolishing 14-day rule for studying human embryos: shots


For decades, scientists were prohibited from keeping human embryos alive in their laboratories for more than 14 days. The ban was intended to avoid a thicket of ethical questions that would be raised by experimenting with living human embryos as they develop.

But on Wednesday, an influential scientific society recommended removing the general taboo, known as the “14-day rule.” the International Society for Stem Cell Research released new guidelines that it could be allowed to study live human embryos in the lab for more than two weeks.

This guidance will now be taken into account by the regulatory bodies in each country that conducts this type of research when deciding which research will be authorized and how. Currently in the United States, regulators at universities and other research institutes universally adhere to the 14-day rule. If the new directions are adopted, that would be a major change.

“When you ask, ‘Is this morally wrong?’ Well, you also have to say the opposite: are there any ethical issues with not doing research during this time? “said Robin Lovell-Badge of the Crick Institute, who chaired the working group that drafted the guidelines. “In many ways, you could argue that it would be unethical not to.

Studying embryos as they develop beyond 14 days could help scientists solve many medical problems, including infertility, miscarriages and birth defects, say Lovell-Badge and others.

“There are very good reasons for doing this research. And people shouldn’t be afraid about it if there are strong mechanisms for review and oversight, ”says Lovell-Badge.

While the new guidelines are welcomed by many scientists and bioethicists, others criticize them as being far too permissive.

“I think it’s deeply disturbing,” said Dr Daniel Sulmasy, bioethicist at Georgetown University. “Now any sign of respect for the human embryo is gone.”

Others are particularly concerned that the new guidelines do not include a clear stopping point for how long a developing embryo could be studied in a lab box.

“If you don’t have an end point, could you bring the embryos to 20 weeks? To 24 weeks? Is viability the only end point,” says Hank Greely, Stanford University bioethicist who, moreover, praised the new guidelines. “Is sustainability even an end point?”

Lovell-Badge defended the recommendations.

“I felt that it would be both difficult and a little pointless to come up with a new limit, which would be arbitrary, a bit like 14 days,” says Lovell-Badge.

The original deadline was set at 14 days for various reasons. For example, 14 days is roughly when an embryo begins to develop the first signs of a central nervous system. It is also when an embryo can no longer divide into twins. At the time, scientists were far from being able to keep embryos alive in the lab for nearly 14 days.

But in recent years, scientists have gradually extended the shelf life of human embryos in laboratory dishes, increasing pressure from some researchers and bioethicists to revise the rule.

At the same time, scientists have developed the ability to create “embryoids,” which are living entities made from human stem cells that have become increasingly complex and similar to human embryos. This added pressure to expand the rule so scientists can compare these new entities to naturally conceived embryos.

“This developmental period between, say, 14 days, which is the current limit, and say 28 days, a tremendous amount is going on. It’s a very critical period,” Lovell-Badge says.

The guidelines insist that such experiments should only be allowed after each country has had vigorous public debate and the general public has agreed that such research is acceptable. Additionally, any experience should be carefully monitored to ensure that research is absolutely necessary to learn something important, as directed.

“We’re not saying it should happen now. We say it is possible that this will happen, ”says Lovell-Badge.

The guidelines could be particularly influential in countries that do not have laws or regulations governing this type of research.

In the United States, the federal government does not have the right to fund research on human embryos. But this kind of research can be done with private money. And the National Institutes of Health have waited for the new guidelines to help decide whether or not to lift a moratorium on funding for research involving chimeric embryos.

“We look forward to reading the guidelines from the ISSRC,” the NIH said in a statement to NPR. “The ISSRC has long been a thoughtful voice for the international stem cell research community, and we will certainly give careful consideration to their report.”

Martin Pera, a Jackson Laboratory stem cell researcher who was not involved in drafting the guidelines called them “responsible and thoughtful,” in an email to NPR. “Adoption of these guidelines by regulatory bodies will ensure that research that has broad potential to improve human health can proceed with appropriate ethical oversight.”

Changing the 14-day rule is just one of many sensitive areas of scientific research addressed by the new guidelines, ranging from human cloning to the genetic modification of human embryos. Certain research, such as human cloning and the creation of babies from genetically modified embryos, remains prohibited. But the guidelines generally take a more permissive stance, including opening the door to the creation of one-day genetically engineered babies if that would be safe and solve a significant medical problem.

The guidelines also detail the rules that would allow researchers to create “chimeric” embryos for research. They are half-human, half-animal embryos. They are made by injecting human stem cells into animal embryos. Scientists recently announced that they did it with monkey embryos.

The goal is to learn more about basic embryonic development and perhaps one day use these embryos to raise animals such as pigs and cows with human hearts, livers and kidneys for transplants. organs.

These entities raise many difficult ethical questions. One concern is that the cells could end up in other parts of the animals’ bodies, such as their brains.

“There are surely human-animal chimeras experiments which are quite permissible and good. But there are some which would be monstrous,” wrote J. Benjamin Hurlbut, an Arizona State University bioethicist, in an email to NPR.

“Do we really need to look back at Mary Shelley to remind ourselves that producing monstrosity can well give rise to a mistaken sense of good – combined with the thrill of controlling power over life?” What is at stake here if not that? “Hurlbut wrote.

To allay these concerns, the guidelines recommend a variety of restrictions and steps you can take to prevent this from happening.

“There is a way to genetically modify both the embryo and the stem cells so that the stem cells only make one particular organ,” says Insoo Hyun, bioethicist at Harvard and Case Western Reserve universities, who helped write the guidelines. “No one wants a chimeric embryo to turn into a half-human, half-animal thing that has human cells intermingled from head to toe.”

But the guidelines could allow a human-ape embryo to develop in a monkey’s womb. And so, this requirement hardly satisfied the critics.

“I think we just haven’t thought about the moral status of these new beings,” says Françoise Baylis, a bioethicist at Dalhousie University in Canada.

“I think a number of people would be, you know, rightly concerned that there are very few constraints on what’s going on with the human embryo.”

Hurlbut, who called the new guidelines “mind-blowing”, agrees.

“What was ethically unthinkable just a few years ago is being treated as not only permissible but even problem-free now,” says Hurlbut.

“Under these guidelines, an oversight committee can deliberate behind closed doors and quietly give scientists its blessing to impregnate a monkey with a part-human embryo, or to see how far human development scientists can cultivate. artificial human embryos constructed in bottles. “

Others, however, praised the new guidelines.

“As we are in a time of rapid advancement in stem cell-based research, it is essential to have a set of guidelines that all researchers can refer to, regardless of the stage of their research,” says Juan Carlos Izpisua Belmonte, researcher at the Salk Institute, who created the half-human, half-ape embryos.


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