Researcher grew mouse embryo in artificial womb. Wants to conduct the experiments with humans

Researcher grew mouse embryo in artificial womb. Wants to conduct the experiments with humans

A group of biology researchers in Israel have grown a mouse embryo in an artificial womb for “as long as 11 or 12 days, about half the animal’s natural gestation period,” the MIT Technology Review reports. 

The breakthrough was lauded by the team responsible as “[setting] the stage for other species,” including developing the technique for human embryos in the future.

The experiments were conducted on mice that had been fertilized inside a mother mouse and then extracted after five days and grown in artificial “wombs” for a further seven days, meaning they had reached half of their gestational cycle. The mice died after growing too large to be supported by the nutrient-rich fluid in which they were suspended, deprived of the blood supply normally facilitated by the placenta.

Dr. Jacob Hanna, the lead scientist on the team from the Weizmann Institute of Science in Israel which developed the mouse embryos, said he hoped his research “will allow scientists to grow human embryos until week five.”

The team’s report, published in the journal Nature, details a number of experiments carried out by Hanna’s team on the artificially grown embryos, including adding human cells in order to document what would happen.

Since publishing his report, Hanna said in an interview that his team has managed to overcome issues associated with developing an embryo from the first few days of conception, and have successfully extracted newly created mice the day they were fertilized. The mice subsequently grew them, in vitro, for twelve days, the New York Times reported.

Hanna has stated that his goal is to develop human embryos using the same technique. That would mean that, after extracting an embryo, a baby with very recognizable characteristics like limbs, a head, and a beating heart, would be grown inside glass bottles attached to a mechanical uterus. He admitted that there might be opposition to his plans to create 12-week-old babies for experiments, saying: “I do understand the difficulties. I understand. You are entering the domain of abortion.”

He did not, however, recognize this as any reason to curtail or in any way alter his plans.  Rather, he justified conducting such experiments on the basis that research is already being undertaken on five-day-old human embryos, the result of which is their destruction. 

“So I would advocate growing it [a human embryo] until day 40 and then disposing of it,” Hanna said. “Instead of getting tissue from abortions, let’s take a blastocyst and grow it.” 

The ability to study up to fifty percent of a pregnancy in vitro “is a gold mine for us,” he said. “I want to see how the program unfolds. I have plenty to study.”

Hanna spent “six years of very intense work to get this system to where it is,” and is now able to artificially support and grow mice in mechanical uteri. The mice are kept in glass vials and rotated constantly, so as prevent them from attaching to the walls of the glass bottles, which would deform and destroy them. The embryos are incubated and hooked up to ventilators, which regulate a supply of oxygen and carbon dioxide. “We do have the goal to do it with synthetic embryos as well,” said Hanna.

As things stand, there is a roadblock hindering Hanna’s human embryo designs  - namely, an international standard restricting researchers from cultivating fertilized humans beyond two weeks, the so-called “14-day rule.” The rule, first published in 1979, has been in effect for over 40 years and has been incorporated into law in some countries, including the U.K. and Japan, but only exists as a guideline in the U.S. and China, among others.

The body responsible for overseeing guidelines in this field of research, the International Society for Stem Cell Research (ISSCR), has recently announced its intention to update the 14-day rule in May this year, when it is expected they will extend embryo culturing indefinitely, with no hard upper time-limit being suggested.

On account of the upcoming abrogation of a limit, Hanna said he is certain that Israeli authorities will give his research the green light for use on human embryos. 

“Once the guidelines are updated, I can apply, and it will be approved. It’s a very important experiment,” he said.

“We need to see human embryos gastrulate and form organs and start perturbing it. The benefit of growing human embryos to week three, week four, week five is invaluable,” he said. “I think those experiments should at least be considered. If we can get to an advanced human embryo, we can learn so much.”

Hanna again recognized that experimenting on humans in this fashion would be unacceptable to some. He suggested that such people might be satisfied if he was to genetically modify his subjects such that they would not develop in a full and healthy manner, for instance, to prevent the heart from ever beating.

Dr. David Prentice, President and Research Director at the Charlotte Lozier Institute (CLI) said that “The mere suggestion by the senior author of this study in Technology Review that human beings could be similarly gestated in bottles for experiments is abhorrent and only sets the stage for human tragedy.”

In a statement, Prentice said that if the 14-day rule is dropped “we can be sure that living human embryos will be grown outside the womb up to at least 33 days post-fertilization–almost five weeks after conception, when the heart is fully beating and the brain undergoes some of its most rapid growth.”

“Human embryos should not be grown for research, manipulated like mice in a lab, or used instrumentally at all. Those who care about the sanctity of life support a zero-day limit that will preserve respect for every human life and refrain from exploitation of or injury to human subjects.”

Commenting on the recent experiments in Israel, Prentice pointed out that “the scientists did more than just grow the mouse embryos outside the womb – they also manipulated them and performed gene editing techniques and even produced a human-mouse embryo chimera, an unnatural species with both mouse and human parts (including the brain)."

Dr. Michael J. New, associate scholar at the pro-life Charlotte Lozier Institute said that the plans to open up human embryonic research indefinitely “could even allow for gruesome practices involving widespread harvesting of fetal organs.” 

“Historically, the scientific community has done a poor job setting ethical limits for its research practices,” New said in a statement. “For instance, few in the scientific community have raised ethical concerns about using the body parts of aborted babies for research.”

The Review asked Hanna if he had sought counsel with any ethicists or religious representatives, like a priest, on the application of his research to humans, to which he responded: “The ISSCR is my rabbi.”