Science and Technology Moving Closer to Artificial Wombs and Artificial Procreation

Peter Diamandis writes in his email blast this week, “Imagine creating an embryo from a stem cell. Even further….imagine giving birth to a baby without an egg and a sperm…using an artificial womb.” This sounds like Aldous Huxley’s “Brave New World,” the English author who foretold in his novel a foreboding vision of the future.

Peter goes on to describe how this seamlessly impossible capability is much closer to reality as he discusses work by two different research teams working with synthetic mouse embryos created from stem calls rather than eggs and sperm, and about keeping the embryos alive for almost the gestational period for mice using artificial wombs. These embryos developed beating hearts and brain stems.

The question of why researchers are doing this is fundamental to Peter’s enthusiasm for this work. He sees it as giving us new medical insights into embryology, an alternative to infertility in parents trying to conceive, and the potential to grow organs that would not be rejected in transplants.

What follows are Peter’s words with a few edits from me. I’d be interested in hearing back from readers about this new scientific endeavour.

Nature’s Black Box

How life evolves from a single fertilized cell to an organism with hundreds of billions or trillions of differentiated cells is a fundamental question scientists are only just beginning to understand. Developmental biologists have made significant progress studying animals whose young develop in transparent eggs, such as zebrafish and frogs. But mammalian development is harder to observe because it takes place inside a uterus. Ethical concerns and tight regulations complicate research on human embryos even further.

In recent years, there has been progress coaxing embryonic stem cells into structures resembling blastocysts, the precursor of embryos, which provide an essential model for early human development that sidesteps some of these issues. But without the supportive environment of the womb, there’s only so far these so-called “blastoids” can survive, and have the chance to develop into the later stages of embryonic development.

Artificial Wombs and Artificial Procreation

In August of 2022, a pair of papers published by two separate groups shook the scientific world as each demonstrated the use of an artificial womb to keep mouse embryos (derived from embryonic stem cells) alive for 8.5 days. Central to both papers was a complex contraption designed to mimic the environment of the uterus, designed by Jacob Hanna, from the Weizmann Institute of Science in Israel, who led one of the teams. It combines rotating glass vials filled with blood serum and a ventilation system that maintains pressure and oxygen levels.

But the artificial womb wasn’t the only innovation. In 2018, Magdalena Zernicka-Goetz, who has dual appointments at Caltech and the University of Cambridge and led the other team, discovered that embryonic stem cells developed further when combined with stem cells from two structures key to early development: the placenta and yolk sack.

By combining these two breakthroughs, the two teams were able to create synthetic mouse embryos that developed to the stage where the basic body plan starts to emerge. This included complex structures including beating hearts, primitive brains, and the beginnings of a gut.

Game-Changing Capabilities

The most obvious impact these advanced synthetic embryos could have is helping scientists crack the underlying code of development. This underpins all kinds of critical capabilities such as regeneration, reproduction, and tissue specialization that have significant implications for medicine.

The team led by Zernicka-Goetz is particularly interested in understanding why some pregnancies fail at the earliest stages, and she says that this new model could provide an unprecedented window into these processes.

One of the beauties of this synthetic embryo model is that it should be possible to genetically engineer the stem cells used to build them. This could allow researchers to identify how specific genes contribute to the developmental process.

The other group led by Hanna has even grander ambitions. They have created a startup called Renewal Bio that plans to create synthetic embryos from patients’ cells, whose tissues could be harvested for transplantation. While there’s been significant progress in the ability to grow simple tissues like skin and cartilage, organs with complex 3D structures and vasculature have been more challenging. Hanna believes that relying on the body’s own developmental processes might be a better approach. “We view the embryo as the best 3D bioprinter,” he told MIT Technology Review. “It’s the best entity to make organs and proper tissue.”

Among the potential applications are collecting blood cells from embryos and transfusing them into patients to rejuvenate their immune systems, or using cells from rudimentary ovaries to help women extend their fertility later in life.

Ethical and Scientific Challenges

Efforts to reinvent human biology inevitably raise thorny ethical challenges. While guidelines vary among countries, human embryos are typically not allowed to develop beyond 14 days, which is the point at which they start to develop from an amorphous blob of cells into something resembling a body.

Renewal Bio envisages developing its embryos to 40-day or 50-day equivalents to gestation in pregnancies. While there is still the question of these entities being viable, the further along the developmental pathway the murkier the ethical implications. One potential solution suggested by Hanna is to genetically engineer the precursor stem cells so that the embryo never develops a brain and head, avoiding any concerns about experimenting on a potentially conscious being.

Other researchers have argued that the concerns about synthetic embryos with no potential to develop into living beings do not outweigh the concrete benefits to people on organ donor waiting lists.

But while these ethical challenges are considerable, experts say the technical ones are probably a more pressing concern. The efficiency with which stem cells can be coaxed into embryo-like structures is still very low, with less than 1% of all cell cultures doing so successfully. And even when they do, the synthetic embryos feature many defects that raise questions about whether they are truly useful models for development. And moving from mouse stem cells to human ones is not a trivial step, not least because it takes considerably longer for human embryos to reach a similar stage of development.

Final Thoughts

We remain a long way from the feasibility of the technology to combat aging or the regeneration of organs on demand, but it’s important not to understate its potential. Despite these cautious assessments of what lies ahead, experts liken these latest developments to the time when the first cloned sheep, Dolly, was born in 1997.