High-profile paper retracted

A rising stem cell star has retracted a recent high-profile paper because of "serious concerns" with the data. A second paper in Blood by the same group is also under review.

Whether the retraction is due to a mistake or misconduct remains unclear, but a comparison of the papers done by Nature reporters found two sets of flow cytometry plots that seem to be duplicates.

Amy Wagers, a stem cell biologist at the Joslin Diabetes Center and assistant professor at Harvard Medical School, published a retraction with two co-authors on Wednesday (October 13) of a January 2010 Nature paper, cited 13 times, which found that factors in the blood of young mice can rejuvenate blood stem cells in older mice.

"This is a shame because I thought the results were really exciting," said Deborah Dunn-Walters in an email, a researcher studying aging at King's College London School of Medicine who had highlighted the results in a recent Current Opinion in Immunology paper. "I am disappointed that the results may not be what they seemed to be," she said.

Wagers, a Howard Hughes Medical Investigator, was dubbed a "Scientist to Watch" by The Scientist in 2008.

The retraction cited new concerns that "undermined the authors' confidence" in the paper's conclusions. But not all the authors agree -- first author Shane Mayack, then a postdoctoral fellow in Wagers laboratory, did not sign the retraction, maintaining that the results are still valid. Mayack did not return an interview request, and is currently no longer employed at Joslin, according to Joslin spokesperson Eric Bender.

A second paper co-authored by Mayack and Wagers, published in the August 2008 issue of Blood -- which found that signals from osteoblasts directly affect and mobilize blood stem cells -- is currently under review. Wagers brought concerns about the differentiation of the osteoblasts in the experiment to the attention of the editors, according to a notice of concern published yesterday (October 14) on the journal's website. The paper has been cited 24 times since its publication in 2008. The journal will wait to take further steps until the institutional investigation is concluded, Blood managing editor Anna Trudgett told The Scientist.

Joslin is currently reviewing the matter in conjunction with Harvard Medical School, according to a statement from the Center, published by the Boston Globe. (The story is also being tracked by the Retraction Watch blog.)

Wagers joined the Joslin Center in 2004 following a postdoc with renowned stem cell biologist Irving Weissman at Stanford University. In Weissman's lab, she earned a reputation for putting other people's findings to the test.

"I regret any confusion that has resulted from the publication of this paper and am deeply grateful to my colleagues who are painstakingly working with me to replicate these experiments and evaluate the data," Wagers wrote in a statement to The Scientist, which was also sent to other media outlets. She did not elaborate further.

Wagers is the author of a series of highly cited papers in the stem cell field, including a 2002 Science paper cited 828 times, a 2004 Nature paper cited 727 times, and a 2004 Cell paper cited 412 times.

"Amy's response is entirely appropriate -- it takes this off the table but it doesn't necessarily mean the concept is wrong," Kenneth Chien, a stem cell researcher also at Harvard Medical School, told Nature.

Wagers did the right thing retracting the paper as soon as she had concerns, said Dunn-Walters. "We all have to have complete confidence in our data and it takes courage to stand up and say, 'We might have been wrong.'"


Related stories:

Postdoc fudged epigenetic data
[22nd September 2010]

10 retractions and counting
[26th May 2010]

Amy Wagers: Setting the record straight
[1st January 2008]