Respected stem cell expert Yoshiki Sasai, who was connected to a scandal accusing a researcher he advised of falsifying a stem cell breakthrough, was found dead today of an apparent suicide. Sasai, who told the Wall Street Journal in April he was "overwhelmed with shame" over the scandal, was found hanging from a stairway handrail at a research facility at the Riken Center for Developmental Biology in Kobe where he’d served as deputy director. Though a Riken spokesman won't speculate as to whether the scandal is to blame, colleagues tell the Japan Times Sasai had been hospitalized and received counseling since the news broke, and a Riken official says he seemed "both physically and mentally exhausted" recently. An internal investigation had cleared Sasai of misconduct, but determined he was accountable for not catching Haruko Obokata’s mistakes.
Sasai, 52, left at least three letters behind, each addressed to Obokata, Riken officials, and colleagues, reports the AP; he also left two apparent suicide notes on his secretary’s desk. Meanwhile, Obokata is trying to replicate results of the renounced study under video surveillance, according to the Washington Post. Sasai had advised Obokata and checked over her research papers—both retracted from Nature in July after being published in January—which had supposedly shown that stem cells could be made by exposing regular cells to acid. In April, Sasai wrote of his deep shame for failing as Obokata’s mentor. The president of Riken says Sasai was "invaluable to the global scientific community," and a government spokesperson lauded him for contributing significant research in regenerative medicine. (Read more stem cell research stories.)