A Little Acid Turns Mouse Blood Into Brain, Heart And Stem Cells

The heart beats in a mouse embryo grown with stems cells made from blood.

Back in 1958, a young biologist at Cornell University made a stunning discovery.

He took a single cell from a carrot and then mixed it with some coconut milk. Days went by and the cell started dividing. Little roots formed. Stems started growing. Eventually, a whole new carrot plant rose up from the single cell.

Imagine if you could perform a similar feat with animal cells, even human cells.

A team of Japanese biologists say they've taken a big step toward doing just that, at least in mice. Instead of using coconut milk, though, the magic ingredient is something akin to lemon juice.

Biologist Haruko Obokata and her colleagues at the RIKEN Center for Developmental Biology say they've figured out a fast, easy way to make the most powerful cells in the world — embryonic stem cells — from just one blood cell.

The trick? Put white blood cells from a baby mouse in a mild acid solution, Obokata and her team report Wednesday in the journal Nature. Eventually a few stem cells emerge that can turn into any other cell in the body — skin, heart, liver or neurons, you name it.

For decades, scientists have been searching for easy ways to make human embryonic stem cells. These cells hold great potential for treating diseases such as Alzheimer's, Parkinson's, heart disease and diabetes.

But for a long time, human stem cells were essentially off limits for researchers because the only way to get them was by destroying human embryos.

Then in 2007, another team of scientists at the RIKEN center figured out a way to make human stem cells from skin and blood by manipulating the cell's genes.

That discovery won the team the Nobel Prize in 2012 and opened a whole new avenue for exploring the power of stem cells. But that process has come with its own set of problems.

"It's quite messy, and we don't really understand how it works," biochemist Austin Smith of the University of Cambridge tells NPR's Rob Stein.

Making Stem Cells From Blood Two white blood cells start acting like embryonic stem cells (green) after spending time in an acid.

In contrast, Smith says, the method developed by Obokata and colleagues, if it pans out, is straightforward and doesn't involve any manipulation inside the cell, only a small change in the cell's environment.

Obokata and her team tested a whole range of treatments in the hopes of creating stem cells, including starving the blood cells, heating them up and even squeezing them through a thin pipette.

What worked the best was simply putting the blood cells in a mild acid for about 30 minutes. The pH of the solution was about 5.7, or a little more acidic than milk. A few days later, the cells stopped acting like blood and started behaving like stem cells.

When the researchers injected the cells into a mouse embryo, the cells acted just like other stem cells: They created all the organs needed for an adult mouse. The team named the cells stimulus-triggered acquisition of pluripotency, or STAP.

"It seems like a new paradigm," says Smith, who wasn't involved with the study. "The method could have many applications, but it really depends on finding out if and how we can extend this [method] in humans."

The researchers don't know whether the method works with blood from adult mice. So far, all of the experiments have used cells taken from infant mice just 1 week old.

"The cells are only a few days old," Smith says. "But we need to know if it works with adult cells and in human cells." That would be essential if the cells are to be used for medical treatments.

And of course, even if the method does work with human cells, there's still a long, long way to go before the cells could be tested in humans.