A FORMER member of one of the highest-profile teams in stem cell biology has been found guilty of falsifying results.
Last year, the work of researchers led by Catherine Verfaillie of the University of Minnesota in Minneapolis became mired in controversy after 快猫短视频 pointed to irregularities in their published results. Now an expert panel called in by the university to investigate one set of irregularities has ruled that a PhD student on the team, , falsified data.
Verfaillie鈥檚 group shot to prominence in 2002 when their paper in Nature (vol 418, p 41) suggested that a rare type of adult stem cell from bone marrow 鈥� first isolated by Reyes 鈥� could give rise to all the body鈥檚 tissues. This had previously been seen only in embryonic stem cells (ESCs).
Advertisement
The findings were seized on as an alternative to ESCs by self-styled 鈥減ro-life鈥� activists 鈥� who oppose the destruction of human embryos to isolate stem cell lines. But other researchers were unable to repeat the results.
The verdict of falsification relates to an earlier paper on the cells, published in Blood (vol 98, p 2615) in 2001, that formed part of Reyes鈥檚 PhD work. Less well known than the Nature paper, the Blood paper is significant because it describes cells isolated from the bone marrow of humans rather than experimental mice.
Last year, 快猫短视频 revealed that images in the Blood paper documenting the presence of proteins in the stem cells also appeared in a US patent (number 7015037), where they were supposed to have originated in different experiments. 快猫短视频 also found that the same image, flipped through 180 degrees and slightly altered, was used twice in the Blood paper to represent the results of different experiments.
An expert panel of three scientists has now concluded that the problems ran deeper still. According to a summary of the panel鈥檚 findings released by the university, images in four figures in the Blood paper were falsified by manipulating the originals. For another image, the panel was unable to find the raw data. The university has now asked for the paper to be retracted.
While the panel decided that images in the patent were 鈥渟eriously flawed鈥�, the evidence it found was not sufficient to show that misconduct was involved in their preparation.
The panel also found duplicated data in both the Blood paper and another paper in The Journal of Clinical Investigation (vol 109, p 337), but ruled that these errors were not misconduct. The Journal of Clinical Investigation has been informed of the problems, but the university has not asked for the paper to be withdrawn.
The panel cleared Verfaillie, now at the Catholic University of Leuven (KUL) in Belgium, of misconduct along with the other authors of both papers, but criticised her for inadequate training and oversight of Reyes.
鈥淚 have initiated a number of additional oversight measures designed to further enhance the integrity of research and scientific publications coming from my lab,鈥� Verfaillie says. 鈥淚 am confident that these measures will avoid the recurrence of a similar problem in the future.鈥�
鈥淏iologists worry that the intense competition in stem cell research may cause similar problems in future鈥�
Reyes鈥檚 punishment, if any, is unknown, as the university is not allowed by Minnesota law to reveal disciplinary action against a former student. Now at the University of Washington in Seattle, Reyes disputes the finding that she misrepresented data: 鈥淭hese were honest errors in part due to inexperience, poor training and lack of clear standards,鈥� she told 快猫短视频.
The finding follows an earlier discovery by 快猫短视频 that six graphs prepared by another junior member of the team were duplicated between the Nature paper and one published in Experimental Hematology (vol 30, p 896). An earlier panel found no evidence of deliberate misconduct in this case, but said the work was flawed, because the controls were not carried out correctly.
Biologists worry that the intense competition in stem cell research may cause similar problems in future. 鈥淢y concern is that this sort of thing will happen again,鈥� says Arnold Kriegstein, who heads the Institute for Regeneration Medicine at the University of California, San Francisco.
Stem Cells 鈥� Learn more about the promise and the controversy in our cutting edge special report .
