Charles Vacanti, a Harvard University professor and key co-author of retracted STAP cell articles, and his fellow Japanese researcher have published a revised method for producing pluripotent stem cells.
“We made a significant mistake in our original declaration that the (previous) protocol was ‘easy’ to repeat,” Vacanti and Koji Kojima said in the revised paper on how to create such cells, referring to a technique they called stimulus-triggered acquisition of pluripotency.
Haruko Obokata, a researcher at the Riken institute, and her colleagues claimed in two articles published in the scientific journal Nature that they had succeeded in creating pluripotent cells that can develop into any body tissue, simply by applying stimuli such as a low acidic solution.
But Obokata and co-authors of the STAP papers, including Vacanti, who was a mentor for Obokata, retracted both articles after a Riken investigation panel concluded that, among other things, Obokata had manipulated some images in one of the papers.
The research team also cited critical errors that had not been discussed by the Riken panel as reasons for the retraction.
Despite the flaws in the papers, Obokata claims that so-called STAP cells do exist. But Riken said in its interim report that its team had yet to verify the procedure devised by Obokata and her colleagues.
In the revised protocol, posted online on Sept. 3, the Vacanti group advises researchers who may try to produce STAP cells to use a low acidic solution containing adenosine triphosphate, or ATP, claiming that it “dramatically increased the efficiency” of the conversion of mature cells into STAP cells as a supplemental energy source.