Pluripotent stem cells injected into a mouse embryo

A leading Japanese research institute has opened an investigation into a groundbreaking stem cell study after concerns were raised about its credibility.

The RIKEN centre in Kobe announced on Friday that it is looking into alleged irregularities in the work of biologist Haruko Obokata, who works at the institution. She shot to fame last month as the lead author on two papers1, 2 published in Nature that demonstrated a simple way to reprogram mature mice cells into an embryonic state by simply applying stress, such as exposure to acid or physical pressure on cell membranes. The RIKEN investigation follows allegations on blog sites about the use of duplicated images in Obokata’s papers, and numerous failed attempts to replicate her results…

That scepticism deepened last week when blogs such as PubPeer started noting what seem to be problems in the two Nature papers and in an earlier paper from 2011, which relates to the potential of stem cells in adult tissues…The corresponding author of that study, Charles Vacanti, an anaesthesiologist at Harvard Medical School in Boston, told Nature that he learned only last week of a “mix up of some panels”. He has already contacted the journal to request a correction. “It certainly appears to have been an honest mistake [that] did not affect any of the data, the conclusions or any other component of the paper,” says Vacanti.

The problems in the two recent Nature papers, on both of which Obokata is a corresponding author (Vacanti is a co-author on both, and corresponding author on one), also relate to images…

Teruhiko Wakayama, a cloning specialist at Yamanashi University in Yamanashi prefecture, is a co-author on both of the papers and took most of the placental images. He admits that the two look similar but says it may be a case of simple confusion. Wakayama, who left RIKEN during the preparation of the manuscript, says he sent more than a hundred images to Obokata and suggests that there was confusion over which to use. He says he is now looking into the problem…

Some researchers do not see a problem yet. Qi Zhou, a cloning expert at the Institute of Zoology in Beijing, who says most of his mouse cells died after treatment with acid, says that “setting up the system is tricky”. “As an easy experiment in an experienced lab can be extremely difficult to others, I won’t comment on the authenticity of the work only based on the reproducibility of the technique in my lab,” says Zhou…

Wakayama says that his independent success in reproducing Obokata’s results is enough to convince him that the technique works. He also notes that the cells produced by Obokata are the only ones known — aside from those in newly fertilized embryos — to be able to produce, for example, placenta, so could not have been substituted cells. “I did it and found it myself,” he says. “I know the results are absolutely true.”

One of the delights of peer review can be failure to corroborate or replicate results. Doesn’t mean the original work is incorrect. It means the system is working.

And more work to corroborate is required.