Acid test for STAP cells

Claims by a Japanese research team that it made pluripotent stem cells simply by exposing normal mouse cells to acid baths and other stresses are now being investigated for "alleged irregulaties," according to an online article Monday in the journal Nature.

Mouse cells exposed to an acidic environment turned into embryonic-like "STAP" cells. These were used to generate an entire fetus. / Haruko Obokata

The study itself was published in Nature on Jan. 29. It gained widespread acclaim, but a number of scientists expressed doubts about the STAP cells on second thought. UC Davis stem cell researcher Paul Knoepfler gave his reasons for skepticism in a Feb. 6 blog post. Among his reasons: Evolution should have selected against such a mechanism, because cellular stress is a common part of life, and pluripotent stem cells produce tumors.

At the very least, researchers who have tried to replicate the findings aren't having an easy time doing so, according to an unscientific poll Knoepfler is running. The trend has turned from mostly positive to evenly split, Knoepfler reported in the second week of polling.

"Its also notable that respondents from Japan have shifted the most in opinion. In week 1 they were disproportionately positive, while in week 2 they became disproportionately negative," Knoepfler wrote.

Jeanne Loring, the TSRI stem cell researcher who I interviewed when the discovery was first announced, told me earlier this month that her lab, "along with everyone else in the universe," was trying to replicate the results.

"What I told my lab was, go ahead and do it; don't tell me about it until you have results, and don't let it interfere with the rest of your work," Loring said.

Life scientists from other fields weighed in on Twitter with their skepticism.

"Acid bath makes stem cells??? If it looks too good to be true, it probably is," wrote tart-tongued evolutionary biologist Dan Graur, who notably applied acid to claims by the ENCODE project (in its press release) that 80 percent of the human genome is functional.

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Acid test for STAP cells