Weekly reads: stembryos or human embryo models, new Macchiarini sentence

Researchers have been making stem cell-based embryo models for years now and a few folks have taken to calling these “stembryos.” Other names like gastruloids and blastoids are sometimes used too.

“Embryo models” might be the simplest and best name.

The embryo model research has advanced relatively quickly from very basic, not very organized structures to models that now are highly similar to the real thing. This has taken only a few years.

Human embryo-like structures could shed new light on early human development.

Multiple teams have reported recently on around two-week-old human embryo models. This has sparked a lot of news and even some conflict this week.

stembryos, embryo models Monash
Stembryos or early embryo models grown from stem cells. Image source: Monash.

Stembryos in the news

Let’s start with this item.

Scientists have created embryo models from stem cells – it could help us better understand infertility and miscarriage, The Conversation.

This story reports on a presentation at ISSCR from Magdalena Żernicka-Goetz on stem cell-based embryo models. Other news outlets also have covered this including The Guardian, which focused mostly on the work by Żernicka-Goetz and Jitesh Neupane.

The Guardian blast on human embryo models or stembryos.
The Guardian piece on human embryo models

I first wrote about the Żernicka-Goetz synthetic embryo work at least 6 years ago here on The Niche.

Part of the news now is perhaps the length of time of embryo model growth: “Żernicka-Goetz described culturing the embryo model to a stage of development just beyond the 14-day stage of gastrulation.”

Here’s a recent preprint from her lab.

Carl Zimmer at NYT has a helpful new piece about the human embryo model work as well.


The Times of Israel has a new piece too: In breakthrough, Israeli scientists say they synthesized human embryos from stem cells.

Hanna is extensively quoted about his unpublished work and there’s a surprising statement at one point (emphasis mine):

“This breakthrough comes on the heels of an article in The Guardian about an announcement Wednesday at the International Society for Stem Cell Research annual meeting in Boston of the creation of a synthetic human embryo by Prof. Magdalena Żernicka-Goetz, of the University of Cambridge and the California Institute of Technology. Prof. Jacob Hanna (Courtesy of the Weizmann Institute of Science) Hanna, who has shared his latest discovery internally within the medical community for the past six months, dismissed Żernicka-Goetz’s announcement as premature. “Her claims are outrageous. She doesn’t even have a pre-print article published. I watched her presentation and saw the few slides she showed. Her model doesn’t have a placenta or a yolk sac, so it cannot be called an embryo. I wouldn’t call it a success,” he said.”

Why the outrage? Is it a battle for who gets credit for being first? Should The Guardian have given Hanna a nod too?

Is one model clearly superior to another?

Could there end up being an IP battle in the human embryoid space?

On a different stembryo front, I found this new CTCF article to be quite cool. Sequential and directional insulation by conserved CTCF sites underlies the Hox timer in stembryos, Nat. Gen.

One of the challenges with human embryo models is their similarity to the real thing, raising all kinds of ethical challenges.

Macchiarini prison time?

Transplant surgeon sentenced to prison for failed stem cell treatments, Science. Also see this from Professor John Rasko in The BMJ:The deadly legacy of a stem cell charlatan.

This isn’t the first time that Paolo Macchiarini has been convicted but maybe this time he’ll serve some time in prison? Or will he be able to avoid it again? After the new verdict:

“At a press conference today with his lawyers, Macchiarini denied he had any intent to harm the patients and claimed he had wanted to help those who had no other treatment options. “The intention of harming is the most awful accusation that you can make to a doctor,” he said. His colleagues and supervisors all approved of the surgeries, he said: “In the operating room we were 20, 25 people. What surprises me is, why I am here alone?” He said his only regret was accepting Karolinska’s job offer, and that he is now “jobless” and does not expect to be able to work again.”

It does seem unlikely he is the only one responsible but he was the leader.

Check out the “right of reply” section in Rasko’s piece, which has some notable responses from the institutions involved.

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