Japanese stem cell scientist Yoshiki Sasai found dead in apparent suicide

Yoshiki Sasai, pictured in Tokyo in April (Getty Images)

A leading stem cell researcher in Japan has been found dead at his laboratory in an apparent suicide after months of pressure over a controversial study that had to be retracted because of scientific errors.

Yoshiki Sasai, 52, was discovered by a security guard on Tuesday morning at the Riken Centre for Developmental Biology in Kobe where he was deputy director. Suicide notes were found at the scene and on his secretary’s desk, it was reported.

Dr Sasai was the supervisor of Haruko Obokata, the lead author of the stem cell papers published in the journal Nature earlier this year in which it was claimed that blood cells can be converted into embryonic-like cells by simply exposing them to a weak solution of acid.

In a subsequent investigation by Riken, Dr Obakata was accused of scientific misconduct and although Dr Sasai was cleared of any direct involvement, he was harshly criticised for failing to provide oversight during the drafting of the now discredited research papers.

Ryoji Novori, the president of Riken, said in a brief statement: “The world scientific community has lost an irreplaceable scientist.”

In 2011, Dr Sasai stunned the world with a study mimicking the early development of the eye with mouse stem cells that produced a three-dimensional optical cup, similar to a human retina, in the laboratory.

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