Research published in Nature that described a simple way to generate stem cells is now under investigation after blog posts called its findings into question.
Dr Haruko Obokata from the RIKEN Center for Developmental Biology, Japan, and colleagues from Harvard Medical School, exposed blood cells from newborn mice to mild acid or physical pressure and generated pluripotent stem cells capable of developing into nearly all of a body's cell types. These were termed 'stimulus-triggered acquisition of pluripotency' (STAP) cells, and the findings were published in two papers on 29 January (reported in BioNews 740).
Following publication, users of the PubPeer website questioned some of the images used, claiming that they seemed duplicated. In one image of a genetic analysis, it appears that one of the 'lanes' has been spliced in. Although spliced images are sometimes used, this is normally made clear and accompanied by an explanation. The bloggers also commented that pictures of two placentas from different experiments looked very similar.
Another blog reported that around ten other researchers have tried to replicate Obokata's result, without success.
It has also been suggested that another paper from Obokata et al, published in 2011 in Tissue Engineering, may have also used image manipulation. However, a Japanese blogger posted recently that 'the problems of some images of the research article could be the result of image compression noise'.
Dr Charles Vacanti, co-author of both papers, told Nature News that he is aware of the mix-up on some images in the 2011 paper, and has contacted the journal to request an erratum. He also stated that the mistake did not affect the results or any other component of the paper, and that it looks like an 'honest mistake'. Vacanti has said that he is happy to make the detailed protocol public.
The RIKEN Center has now launched an investigation and will make their findings public as soon as they are available; however it has confirmed that the investigation is only on the two articles published in 2013. They did not state what the focus of the investigation will be.