Yoshiki Sasai – a tribute to an outstanding scientist

Yoshiki SasaiThe scientific community was shocked this week by the death of stem cell researcher Yoshiki Sasai, who apparently committed suicide in the wake of a high-profile case of scientific fraud. Two papers from the RIKEN Center for Developmental Biology (CDB) in Kobe, Japan, where Sasai had worked – co-authored by him and published in the journal Nature in late January 2014 – described a simple method for converting mature cells into embryonic stem cells, called stimulus-triggered acquisition of pluripotency, or STAP.

It seemed too good to be true – and it was. The findings were challenged and other labs tried but failed to replicate the method. The lead researcher was found guilty of scientific misconduct, and in July both of the papers were retracted. Sasai himself was cleared of any involvement in the misconduct, but the lead researcher did the work under his supervision, and so he was criticised for oversights while the papers were being written up.

I had been working on a feature article for Mosaic about regenerative medicine and Sasai’s work. Earlier this year I visited his lab as part of my reporting for the article – by coincidence arriving at the CDB the day the STAP method hit the news, and so found myself competing with several film crews for his attention. As a result, my visit to the lab was cut short, and I spent far less time there than had been planned. Nevertheless, I managed to interview Sasai and two of his colleagues and take a look around.

The story was originally scheduled for publication this month, and my editors at Mosaic have decided to go ahead and publish it on 26 August. While the story is not about the scandal, we felt that it would be strange not to mention recent tragic events, while at the same time keeping it from overshadowing the real focus of the story. So, apart from a few small changes and the addition of a brief epilogue, it is unchanged.

I spent less time with Sasai than I had hoped, but he struck me as a very proud man, and the remarkable work being done in his lab gave him every reason to be. So I do not doubt reports that he had felt "deeply ashamed" about the STAP cell papers, and the disrepute they had brought to RIKEN, in the weeks leading up to his death. During this time, an independent committee had recommended that the CDB be dismantled, and Sasai's mental and physical health had by then suffered considerably, so I feel doubly honoured to have visited him there when I did.

Sadly, many of the news stories about his death have focused on the unfortunate circumstances that mired the last few months of his life. Mosaic’s staff and I send our deepest condolences to Sasai’s family and friends. We hope that that the Mosaic story will serve as a tribute to the pioneering work of an outstanding scientist.

Mo Costandi

You can read Mo’s feature on Mosaic from 26 August 2014.