Jan. 23 (UPI) -- A Japanese stem cell researcher said he falsified data in a study published in a U.S. scientific journal in 2017.
Kohei Yamamizu, 36, who works with Nobel Prize laureate Shinya Yamanaka at Kyoto University's Center for iPS Cell Research and Application, admitted to the fabrications, the Mainichi Shimbun reported Tuesday.
Yamanaka issued an apology during a news conference, where Yamamizu may not have been present.
"I truly regret and apologize for not being able to prevent the impropriety," Yamanaka said. "I will make even greater efforts in regard to the fostering of researchers."
The falsifying of data in the study published in the February 2017 issue of Stem Cell Reports was extensive.
A Kyoto University committee found 17 instances of information manipulation.
The fabrications were used to fit the authors' claims in an article Yamamizu co-wrote with other scientists.
The other 10 co-authors were not involved in data manipulation, according to the Asahi Shimbun.
The study argues a certain kind of stem cell can be useful in manufacturing drugs that can fight brain diseases like Alzheimer's.
The paper also claimed the scientists have created stem cells that are similar to cells that function to create a blood-brain barrier that protects the brain.
But the thesis came under scrutiny last September, and an investigative committee was created to examine the claims.
The probe began about a month after another Japanese scientist was found to have committed scientific misconduct in five papers.
Yoshinori Watanabe, a cell biologist at the prestigious University of Tokyo, was found to have drawn conclusions without conducting the necessary experiments.
Japan has invested substantially in stem cell research.
In 2013, Tokyo began to invest in the sector by agreeing to supply more than $990 million in funding for stem cell research at the University of Tokyo.