The Riken Institute in Japan has opened an investigation into the recently published stem cell work from Haruko Obokata and her colleagues, the Wall Street Journal reports.
The Riken Center for Developmental Biology's Obokata and her colleagues reported in a set of Nature papers last month that embryonic-like stem cells could be generated by exposing mouse blood cells to a strong stimulus, such as an acidic solution.
As the Journal and Nature News both note, questions began to swirl regarding irregularities in images included in the two recent papers and one older one from 2011. For instance, a discussion at PubPeer indicates that a photo of a placenta appears to have been used more than once.
Two co-authors say it was likely an honest error. Teruhiko Wakayama, who took many of the placental images, tells Nature News that he sent hundreds of images to Obokata. (He left Riken for Yamanashi University while the manuscript was being prepared.) He says there might have been confusion regarding which one to use.
Harvard Medical School and Brigham and Women's Hospital's Charles Vacanti likewise tells the Journal that "I believe, in discussing this with [some of the co-authors], that this was a simple mistake. There was no intention of fraud and it has no impact on the [study's] conclusions."
Still, Nature News adds that researchers, thus far, have run into difficulty reproducing the team's work, though that could be due to a complicated protocol and the use of different cell lines.
Riken says it was contacted by an outside researcher and began its investigation, using a team of internal and outside experts.
The journal Nature also says it is looking into the allegations.