Skip to Content

New Ways to Make Embryonic Stem Cells

If replicated in humans, new procedures developed in mice could be a huge boon to the field.

Scientists at Harvard announced today that they can generate cloned stem-cell lines from fertilized eggs in mice. If replicated in humans, the findings could provide a huge boon to the field of human therapeutic cloning. To create genetically tailored stem cells, which experts say is crucial for understanding and treating disease, DNA from an adult cell is inserted into an egg whose DNA has been removed. The egg begins to develop as a normal embryo would, and scientists harvest stem cells after a few days.

Cloning anew: A novel way to generate cloned stem cells could boost the pace of embryonic stem-cell research.

However, few women have been willing to donate their eggs for research, and lack of this crucial resource has drastically slowed research efforts. Women are paid thousands of dollars to donate their eggs to fertility clinics, but not for research. (See “Lack of Human Eggs Could Hamper U.S. Cloning Efforts.”) Kevin Eggan, a stem-cell researcher at Harvard, was given approval to start therapeutic-cloning research with human eggs more than a year ago, but was delayed for a full year due to lack of eggs.

In the study, published today in Nature, Eggan and his colleagues removed the chromosomes from newly fertilized mouse eggs and then inserted DNA from an adult skin cell. The eggs began to divide, allowing the researchers to successfully harvest stem cells. The procedure worked even with abnormally fertilized eggs, such as those that had been fertilized by two sperm. Such eggs are routinely discarded during in vitro fertilization because they can’t develop normally, but they might provide a new source of materials for cloning experiments. Eggan now plans to try the procedure with human eggs.

Eggan emphasizes that he and his team started the project for practical reasons–to find an alternative resource for therapeutic-cloning research–rather than for ethical ones. Religious opponents of embryonic stem-cell research and therapeutic cloning, especially those who believe that life begins at conception, are unlikely to be swayed by the new procedure.

Three other papers published today–two in Nature and one in Cell Stem Cell–describe an additional way to generate stem cell-like cells in mice. Three independent groups (in Japan, in Germany, and in the United States) were able to revert fibroblast cells–adult cells found in connective tissue–back to an embryonic stem cell-like state by activating four genes expressed in stem cells.

The cells look and behave like embryonic stem cells, showing similar molecular markers and the ability to differentiate into different cell types. If the procedure is replicated in humans, the findings could provide a way to generate tissue-matched cells for patients requiring cell transplants.

But scientists caution that they don’t yet know if the same four genetic factors will work in human cells. In addition, the method is inefficient: only a small percentage of the cells are effectively reverted back to their embryonic state, suggesting that other, as-yet-unknown signals are likely to be important in the process.

Keep Reading

Most Popular

images created by Google Imagen
images created by Google Imagen

The dark secret behind those cute AI-generated animal images

Google Brain has revealed its own image-making AI, called Imagen. But don't expect to see anything that isn't wholesome.

biomass with Charm mobile unit in background
biomass with Charm mobile unit in background

Inside Charm Industrial’s big bet on corn stalks for carbon removal

The startup used plant matter and bio-oil to sequester thousands of tons of carbon. The question now is how reliable, scalable, and economical this approach will prove.

AGI is just chatter for now concept
AGI is just chatter for now concept

The hype around DeepMind’s new AI model misses what’s actually cool about it

Some worry that the chatter about these tools is doing the whole field a disservice.

Peter Reinhardt
Peter Reinhardt

How Charm Industrial hopes to use crops to cut steel emissions

The startup believes its bio-oil, once converted into syngas, could help clean up the dirtiest industrial sector.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.