The debate over new stem cell technique begins

A mouse embryo generated from STAP stem cells.
A mouse embryo generated from STAP stem cells. –RIKEN Institute/Haruko Obokata

Already, scientists in laboratories across the world have begun dipping mature cells in acid, hoping to see whether this simple intervention really can trigger a transformation into stem cells, as reported by a team of Boston and Japanese researchers last week.

At the Harvard Stem Cell Institute, a number of scientists have already embarked on the experiment, which they’re informally calling “stem cell ceviche,’’ comparing it to the Latin American method of cooking seafood in lime and lemon juice. At meetings with other experts and even in casual conversation, stem cell scientists say they are exchanging surprise, doubt, and wonder about the discovery, reported in two papers in the journal Nature.


The range of responses varies widely. But most scientists seem to be surprised and skeptical about the technique, though also impressed by the rigorous testing that experts in the field did on the cells. It appears that no one knows quite what to think.

Paul Knoepfler, an associate professor in the department of cell biology and human anatomy at the University of California, Davis, has been blogging extensively about the discovery and polled his readers about what they think. In an unscientific poll that has drawn about 400 responses, he’s found that scientists are pretty evenly split on whether they are leaning toward believing in the technique or not. Interestingly, he found people responding to the poll from Japan are far more likely to be convinced it is true.

On Thursday, Knoepfler made his own opinion known. It’s a harsh critique, starting with his view that the method is illogical and defies common sense. It ends with questions about why the researchers would only now be trying the technique on human cells, since they seemed to have proved it to themselves for several years now. The biggest mystery may be why, if simple stress can trigger cells to return to a stem cell-like state, it doesn’t happen more often in the body. Why don’t people just have lots of cancers and tumors in the acidic environment of their stomach, for example?


There are also basic questions about whether these truly are the same as “spore-like cells’’ that Dr. Charles Vacanti, an anesthesiologist at Brigham and Women’s Hospital who led the new work, described in a highly controversial 2001 paper. Many scientists doubted the existence of those cells, and Vacanti has said he thinks the new stem cells, which are called STAP cells, are the same.

“Obviously, it has to be reproduced. That’s the caveat,’’ said Dr. Kenneth Chien, a professor in the department of cell and molecular biology and medicine at the Karolinska Institute in Stockholm. “I still think it’s shocking. And it makes me wonder if it’s true or not, it’s so shocking.’’

Right now, we seem to have arrived at an unusual spot in science — no one knows quite what to believe. People have quite informed gut reactions, but still seem to lack solid evidence to show the technique does or doesn’t hold up. It’s exciting and nerve wracking, but even those with doubts don’t seem ready to dismiss it outright. This is how science works: people turn to the experiments to smash or solidify their doubts. Many are scurrying to recreate those in their laboratories, which should bring some clarity to the situation.

One reason the finding is so unusual is that it pretty much blind-sided the scientific community. Often, researchers are aware of discoveries that will be published in their fields through informal channels. They attend the same meetings, they present early versions of their results, or they know who is generally working on what area of research. In this case, people were surprised. That’s in part because one of the scientists pushing the work was far from an insider. Vacanti is an anesthesiologist, not a stem cell scientist.


Notably, even though the team of researchers was partially based in Boston, where there are many leaders in the stem cell field, they turned to world experts in Japan to vet the cells.

If other scientists have trouble getting the same results, attaining clarity may take even longer, because they will need to troubleshoot to see whether there is some nuance to the procedure they may have missed.

Dr. Leonard Zon, a stem cell scientist at Boston Children’s Hospital spoke from a meeting on cancer and stem cells in Canada. He said already, he’s spoken to a number of scientists working to repeat the work.

“It definitely has stimulated a lot of discussion,’’ Zon said. “I guess I’m not so sure. But it’s easy enough to do, so a lot of people will do it.’’

Even doubters like Knoepfler hold out hope that he could be wrong.

“I believe the odds are it won’t work, at least not in a reasonably close fashion to what was reported in these Nature papers,’’ Knoepfler wrote on his blog. “I really hope I am wrong and if I am you’ll read my happy mea culpa right here.’’

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