Japanese researcher found dead amid a swirling stem cell research scandal

Yoshiki Sasai, former deputy director of the Riken Center for Developmental Biology--Courtesy of Riken

One of the authors of a controversial and now-retracted paper purporting a stem cell breakthrough has been found dead in what appears to be a suicide, according to numerous reports, following an investigation that has alarmed researchers and rattled one of Japan's most respected institutions.

A security guard found Yoshiki Sasai's body at the Riken Center for Developmental Biology, where he was deputy director, The Guardian reports. Authorities said he left "farewell notes," according to AFP, addressed to his secretary, his colleagues and his fellow researchers. He was 52.

Sasai's decades-long career established him as a well-respected expert on embryonic stem cells, but a scandal-plagued 6 months tarnished the reputation of the scientist and his institution, putting him at risk for disciplinary action in the wake of an embarrassing retraction.

It began in January when Riken researcher Haruko Obokata and a group of co-investigators including Sasai announced that they had made a breakthrough discovery in the stem cell field. Their findings, published in Nature, suggested that one could engineer therapeutically useful stem cells simply by exposing healthy adult ones to trauma and acidic conditions. The researchers touted their work as potentially providing a path forward in stem cell research that avoided more difficult (and politically fraught) approaches to cellular reprogramming.

In the ensuing months, however, cracks in the veneer emerged as other scientists failed to replicate the group's findings. That spurred a Riken-led review of the paper that found at least four errors and two instances of outright fabrication, leading a panel of investigators to single out Obokata and question her integrity. In July, Obokata, Sasai and the 9 other co-authors retracted their report, saying in a letter that "multiple errors impair the credibility of the study as a whole and we are unable to say without doubt whether the ... phenomenon is real."

Sasai, a senior Riken researcher tasked with overseeing the younger Obokata's work, was reportedly overcome with shame as the scandal unfolded, and officials told The Wall Street Journal he had recently appeared "both physically and mentally exhausted."

Riken President Ryōji Noyori said in a statement that Sasai's death left him "overcome with grief."

"The scientific world has lost a talented and dedicated researcher, who earned our deep respect for the advanced research he carried out over many years," Noyori said.

- read the Guardian story
- here's AFP's take
- get more from WSJ (sub. req.)
​- here's Noyori's statement (PDF)

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