I’ve learned two new words in the last two days: eponymous (“self-named” or named after the thing itself) and “corrigendum” (a correction of an error found after printing, which is corrected with a separate printed page.) I just had to use the latter in my title.
The journal Nature has retracted (sorry, subscription only) a single figure from a 2002 report (free abstract, here) on the successful identification and culture of multipotent adult stem cells, from the lab of Catherine Verfaillie, Ph.D., formerly of the University of Michigan. Besides witnessing an example of scientific integrity on the part of Nature and the authors, we may also be witness to a demonstration of integrity and ethics within the scientific community.
It’s important to note that the actual data and the conclusions of the report are no longer in question, if they ever were. The problem was with this single picture, depicting the results of flow cytometry of the cells identified as multipotent adult progenitor cells (MAPCs). The existence and significance of the MAPCs is not in question. The description of the methods and results of the original team has been blamed for the difficulty of reproducing the experiment.
The Scientist reports that Irving Weissman, Ph.D, formerly skeptical of the conclusion that the adult cells were indeed multipotent, has since worked with and published another report on the MPACs with Dr. Verfaillie’s team and now supports her conclusion, at least tentatively:
Irving Weissman, director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine in California, co-authored a 2007 study with Verfaillie, and said he believes Verfaillie is innocent of any foul play. Verfaillie “has a long record of solid, reproducible work. I can’t conceive that, if there is a systematic error, she participated in it,” he said.
“Nevertheless at the very least, the markers associated with the cells [in the Nature study] can’t be taken as gospel,” Weissman continued. In the case of Verfaillie’s MAPCs, he said, “it is conceivable that [Verfaillie] found a way of tissue culture isolation of pluripotent cells that was difficult to reproduce.”
There must be room in everything we do for correction of mistakes. We are once again reminded that science is the process of discovering what can be discovered and reproduced in different labs, at different times, using the same methods.