The University of Minnesota is asking a leading academic journal to retract a stem cell study published by a former university researcher. The researcher agrees there were errors in the study, but stands by its results.
The University of Minnesota has concluded that falsified data were used in the 2001 article on adult stem cell research.
The conclusion follows an 18-month investigation into research published by stem-cell expert Dr. Catherine Verfaillie.
The investigation clears Verfaillie of misconduct but points to a former graduate student, Dr. Morayma Reyes, who is now an assistant professor at the University of Washington.
The university blames Verfaillie for "inadequate training and oversight," and says it has asked for a retraction of the published article, which appeared in the journal Blood.
Reyes said 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 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.
Verfaillie now works at Catholic University in Belgium. She responded to MPR via e-mail, saying she agrees that the Blood paper should be retracted.
She also said she takes "ultimate responsibility" for the work performed in her lab.
"The university concluded that allegations against me personally were not substantiated, and that I was not responsible for the alleged manipulations," said Verfaillie. "Nevertheless, I am extremely sorry about this, as I was the senior author on the paper and did not notice the problems with these figures."
Verfaillie added that she disagrees with the university's criticism of her oversight and mentoring.
"I am committed to honesty in the pursuit of science. The methods that were followed in my lab at the time of the research in question were, and still are, common practice in the scientific community," Verfaillie wrote.
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.
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.
Both Verfaillie and Reyes said the errors in no way altered the conclusions of the paper, and the research has since been successfully reproduced by other scientists.
Mulcahy said it's not clear how, or if, the discovery will affect the underlying findings of the research.
"That's an issue that ultimately the scientific community will have to resolve for itself," he said.
(The Associated Press contributed to this report)