* Stem cell studies were initially hailed as breakthrough
* But independent teams could not replicate findings
* Nature says "multiple errors" impair work's credibility
(Adds statement from Harvard researcher Charles Vacanti)
By Kate Kelland, Health and Science Correspondent
LONDON, July 2 A stem cell paper published by a
team of Japanese and American scientists in the influential
journal Nature has been retracted due to "several critical
errors", the journal said on Wednesday.
The research, which when published in January was described
as game-changing by many experts in the field, was subsequently
investigated by Japan's RIKEN scientific institute, which
"categorised some of the errors as misconduct", Nature said.
The paper, led at RIKEN by Japanese researcher Haruko
Obokata, detailed simple ways to reprogram mature animal cells
back to an embryonic-like state, allowing them to generate many
different types of cells.
The results appeared to offer a promise that human cells
might in future be simply and cheaply reprogrammed into
embryonic-like cells - in this case cells dubbed
Stimulus-Triggered Acquisition of Pluripotency, or STAP, cells -
suggesting a simple way to replace damaged cells or grow new
organs for sick and injured people.
Obokata initially staunchly defended her work in the face of
serious doubt and criticisms, but last month agreed to retract
Nature confirmed the retraction on Wednesday, saying
"multiple errors impair the credibility of the study as a whole.
"Ongoing studies are investigating this phenomenon afresh,
but given the extensive nature of the errors currently found, we
consider it appropriate to retract both papers," it said.
Charles Vacanti of Boston's Brigham and Women's Hospital and
Harvard University in the United States, who was a co-author on
the paper, conceded in a statement that "multiple errors" had
been found, and agreed the work should be withdrawn.
"In science, the integrity of data is the foundation for
credible findings," he said. "I am deeply saddened by all that
has transpired, and after thoughtful consideration of the errors
presented in the RIKEN report and other concerns that have been
raised, I have agreed to retract the papers."
Stem cell experts, who at the time expressed excitement
about Obokata's findings, said they were disappointed at the
"The STAP technology, indeed, sounded too good to be true,"
said Dusko Ilic, senior lecturer in stem cell science at King's
College London. "I hoped that Haruko Obokata would prove at the
end all those naysayers wrong. Unfortunately, she did not."
According to the original Nature papers and briefings given
by Obokata in January, she and her team took skin and blood
cells, let them multiply, then subjected them to stress "almost
to the point of death" by exposing them to trauma, low oxygen
levels and acidic environments.
The Japanese-U.S. team said that within days they found the
cells had not only survived but had also recovered by naturally
reverting to a state similar to that of an embryonic stem cell.
These stem cells were then able to differentiate and mature
into different types of cells and tissues, they said.
But other research teams around the world were unable to
replicate the research, and within weeks questions were raised
about the validity of the findings.
RIKEN, a semi-governmental research institute, launched an
investigation and in April said it had concluded "this was an
act of research misconduct involving fabrication".
Chris Mason, an expert in regenerative medicine
bioprocessing at University College London, said the incident
exposed flaws in the peer-review process whereby fellow
scientists are asked to review and comment on scientific studies
before journals accept them for publication.
"This ... highlights that the peer review process does not
end at the recommendation to publish a paper, but continues with
even greater rigour by a wide range of experts in their
laboratories and increasingly across social media," he said.
"Final validation is the reproduction of the data by
independent scientists. This final step is the most important
step in the entire peer review process."
(Editing by Janet Lawrence and Sonya Hepinstall)