The University of Minnesota has concluded that falsified data were used in a 2001 article published by one of its pioneering researchers on adult stem cells.
The stunning admission followed an 18-month investigation into research published by Dr. Catherine Verfaillie, an internationally known stem-cell expert.
The investigation cleared Verfaillie of misconduct but pointed to a former graduate student, Dr. Morayma Reyes, who is now an assistant professor at the University of Washington.
At the same time, the university blamed Verfaillie for "inadequate training and oversight," and said it has asked for a retraction of the published article, which appeared in the journal Blood. Reyes said Tuesday night it was an honest error and there was no intent to deceive.
The study was one of a series that Verfaillie published, suggesting that adult stem cells could be used as an alternative to embryonic stem cells in medical research.
Her research has received international attention because of political and ethical controversies over research involving embryonic stem cells. A panel of experts concluded that four images used in the Blood paper were intentionally altered, according to Tim Mulcahy, the university's vice president of research. "Based on everything they had, they came to the conclusion that data was falsified," he said.
The panel investigated Verfaillie and Reyes, her student, and concluded that the allegations against Verfaillie "were unsubstantiated." Mulcahy said that he could not discuss the findings about Reyes because of privacy laws.
Verfaillie, who now lives in Belgium, could not be reached for comment.
Reyes, who responded to questions by e-mail, said the correction in the journal Blood is warranted. However, she denied falsifying data. She said the university panel said she falsified data by adjusting brightness and contrast in scientific images included in the article. At the time the research was done, that was an accepted practice but it has since changed, she said. The panel judged her on the newer standard.
"The UMN panel did not accept the distinction between inappropriate vs. fraudulent manipulation," Reyes said. She said the university denied her request for a hearing to challenge the panel's decision because she is not an employee. Reyes said the errors occurred because of "inexperience, poor training and lack of clear standards" on the handling of digital images.
"I regret very much these errors and never had the intention to deceive," she said.
But Reyes also said they in no way altered the conclusions of the paper, and the research has since been successfully reproduced by other scientists.
It's not clear how, or if, the discovery will affect the underlying findings of the research, Mulcahy said. "That's an issue that ultimately the scientific community will have to resolve for itself."
This was the second time in two years that the University of Minnesota has investigated questions about Verfaillie's research. The earlier inquiry found flaws in two other published papers, which were coauthored with Reyes and several others, but concluded that there was no evidence of misconduct.
Both inquiries were prompted by reports in the magazine New Scientist that questioned the accuracy of the published data.
"I'm just pleased to see the scientific record put straight," said Peter Aldhous, the magazine's San Francisco bureau chief, who wrote the articles.
Aldhous said he decided to take a closer look at Verfaillie's research in 2005 because other scientists were having difficulty replicating her results. That's typically how scientists confirm one another's findings.
Aldhous said he and a colleague studied Verfaillie's published reports, including one in the prestigious journal Nature and discovered that some images were used more than once, to represent different experiments. "We didn't accuse anybody," he said. "We were pointing out, well, this is very strange."
In February 2007, Verfaillie acknowledged the problem but called it an "honest mistake" and published corrections in Nature and another journal, Experimental Hematology. A month later, New Scientist reported that it found more curious duplications in the Blood article and a patent application.
As a result, the university asked three academic experts, including two from other universities, to examine the research in detail, Mulcahy said. They found that four of the original images, which were used to identify stem cells, had been altered.
Mulcahy declined to speculate on the significance of those changes, which he described as "Photoshopping things out or adding things in."
Whatever the intent, he said, "it's a fundamental breach" of scientific conduct.
Mulcahy said he reported the findings to the federal Office of Research Integrity, which investigates scientific misconduct involving federally funded research. The stem-cell research was funded with federal money.
Mulcahy also said that some of the falsified data appeared in Reyes' thesis. While he declined to discuss her case specifically, he said that a finding of academic fraud could endanger someone's academic degree. But he said that student disciplinary proceedings are private.
Aldhous, of New Scientist, called the outcome "a personal tragedy" for those involved. "I don't view it as vindication," he said of the university investigation.
"We're a science magazine. We care about science. We believe science should be about revealing, getting to the truth, as far as we can."