Photo/IllutrationShinya Yamanaka, left, director of Kyoto University's Center for iPS Cell Research and Application, and other officials attend a news conference on Jan. 22. (Yoshiko Sato)

KYOTO--A scientist at a global leader in stem cell research admitted to falsifying data in a study published last year that had raised hopes for future treatments for brain diseases.

Officials at Kyoto University’s Center for iPS Cell Research and Application (CiRA) told a news conference on Jan. 22 that an internal investigation turned up research improprieties in the study. The university has asked the publishing company of Stem Cell Reports to retract the article, which appeared in the U.S. scientific journal in February 2017.

CiRA officials said Kohei Yamamizu, 36, a specially appointed assistant professor who was the lead writer of the article, told the committee that he fabricated the figures to “improve the overall appearance of the article.”

The center said the falsified data would not affect ongoing clinical research and tests using iPS cells, but measures will be taken to prevent a recurrence.

“I truly regret and apologize for not being able to prevent the impropriety,” CiRA Director Shinya Yamanaka, who won the Nobel Prize for his work with human induced pluripotent stem (iPS) cells, said at the news conference. “I will make even greater efforts in regard to the fostering of researchers.”

Yamamizu’s research involved attempts to turn iPS cells into other cells that play an important role in protecting the brain.

The study claimed to have created brain endothelial cells with characteristics similar to cells that go into the creation of the blood-brain barrier. This barrier helps to protect the brain by limiting the activities of molecules that reach it.

According to the paper, the creation of such brain endothelial cells from iPS cells could be helpful in producing drugs to combat brain illnesses, such as Alzheimer’s.

However, doubts were raised about the validity of the paper, and a committee was formed in September 2017 to respond to the allegations.

The university’s research integrity investigation committee found fabrication and manipulation in 17 instances among 11 figures used in the paper. They consisted of all six main figures as well as five of the six supplementary figures used to augment the article.

The committee said the falsifications were made to reinforce the arguments in the paper while the manipulation of figures played a major role in supporting the paper’s conclusion.

When the committee analyzed the proper research data, it concluded that no brain endothelial cells were created.

The figures were all produced by Yamamizu, and none of the 10 co-authors of the article was involved, the committee said.

The university will decide on disciplinary action for those involved based on its internal guidelines.

University officials said they would institute new measures, including requiring the submittal of all experiment notes and sufficient research data to validate the reliability of figures before a study is published.