Stem Cell Community Tribute to Yoshiki Sasai (笹井芳樹)

Yoshiki Sasai

This post is a tribute to the late Dr. Yoshiki Sasai (笹井芳樹). If you would like your name added to this tribute please let me know. You are also welcome to add your own tributes in the comments.

In an era when the emerging field of regenerative medicine is just beginning to take wing, we learn of a tragic loss of a friend and colleague Yoshiki Sasai. Dr. Sasai was widely esteemed by those who knew him as an outstanding developmental biologist. His death is therefore a great loss for both the stem cell and developmental biology fields.

Dr. Sasai was not a scientist who was satisfied with incremental advances; he was creative and visionary. He focused on development of the brain, using pluripotent stem cells to generate self-organizing neural tubes in vitro. This ability to replicate organogenesis in the lab could revolutionize stem cell medicine and he was an important pioneer in this advance. He was also helping to develop a stem cell therapy for macular degeneration.

In short, his pioneering work will inspire regenerative medicine research for decades to come. Future generations will remember Yoshiki Sasai as a scientist who was fascinated by the beauty of embryonic development and was dedicated to understanding how so much complexity could arise so perfectly from the simplicity of a single cell. With this collective statement we wish to pay tribute to him and his exceptional contributions to science. He will be greatly missed.

Paul Knoepfler

Mike West

Bob Lanza

Jeanne Loring

Doug Sipp

Janet Rossant

Bernie Siegel

Jun Seita

Alexey Bersenev

Roman Reed

Zorica Becker-Kojic

Roy W. Smolens Jr.

Harumi Sakaguchi

Cheng-Yoong Pang

M. Chandrashekhar

Kenneth Lee

Jeanne Adiwinata Pawitan

Yu Yamamoto

Rosario Isasi

Christopher Fasano

Peter Burrows

Don Paul Kovarcik

Jennifer Aparicio

Andras Dinnyes, Hungary

Mohamed Elgafi

Nalina Nagarajan

Mitradas Panicker

Florian T. Merkle

Robert H. Broyles

Don C. Reed

Denis Ivanov

Joel C. Glover

Bill Ritchie

Susan Lim

Tim Lee

Donald Newgreen

Joe Riggs

Jayakumar Rajadas

Krishna Pantakani

Asawari Bapat

Caroline Mathen

Luis Meseguer-Olmo

Jason Wen

Tiziano Barberi

Chris Mason

Luciano Conti

André Brändli

Y. Murat Elcin

Tran Doan Ngoc Tran

Magdalene Seiler, UC Irvine

Ahmed Mansouri

Kyle Cetrulo and Curtis L. Cetrulo, M.D.

Alan Fernandez

Carla Mellough

Prabhu Mishra


William W. Bauser

Nikolaos Mitrousis

Xiaodong Liu

Maria Longobardi

61 thoughts on “Stem Cell Community Tribute to Yoshiki Sasai (笹井芳樹)”

  1. A tremendous loss for the scientific world !! We have lost a great scientist who has given new hope…add my name also

  2. Magdalene Seiler

    Dear Paul,
    Please add my name. We all owe a lot to Dr. Sasai’s creativity.
    Magdalene Seiler, UC Irvine

  3. It has been a tremendous loss for the stem cell field.
    Please add my name to the list of colleagues that wish to honor Yoshiki Sasai, a brilliant man and scientist.

    Luciano Conti

  4. Tara Bryant-Gray

    Why isn’t our culture celebrating people like this brilliant scientist every single day instead of celebrity worship? Yoshiki Sasai was a hero and others like him will change our world and the lives of millions suffering with diseases and conditions.

  5. Please add my name: Donald Newgreen
    Yoshiki Sasai’s death is a major blow to regenerative medicine research and an important lesson in the disproportionate interaction of a scientific problem (which was a minor misstep in the grand scheme of science) and the general media, with its hunger for dispute and sensation.

  6. I wish so much he had talked with some of his friends before apparently taking his life. We none of us belong to ourselves alone; he had much more to give the world. Please add my name, Don C. Reed

  7. Florian T. Merkle

    The news hit me hard. Please add my name as well to honor this great scientist.

    Florian T. Merkle

  8. All of us at the California Project to Cure Blindness wish to convey our condolences and also our encouragement to continue efforts at RIKEN to develop stem cell based therapies for ocular disease.

  9. I, too, am saddened by passing of Dr. Yoshiki Sasai. This tragic death of Dr. Sasai was driven by aggressive reporting of two major Japanese media, NHK TV and Mainichi Newspaper, among others, and Riken’s inability to control criticism made by a few scientists who disagreed with Dr. Obokata’s paper that was published in the British magazine, Nature. Disagreement is common to any scientific discoveries, and it promotes others to pursue challenging research, which is healthy for scientific advancement. We have witnessed this since the day human beings showed interests in scientific truth early in our civilization. However, it becomes ugly when the disagreement turn into political judgement of right and wrong. In science, there is no right or wrong, only the truth. How many discoveries were made in the past by so called mistakes or by accident? The media have no right to judge scientific works. It should report what was done and nothing more, and follow how these discoveries unfold. Dr. Obokata is a promising Japanese female scientist. Dr. Sasai gave her an encouraging word to Dr. Obokata in his death note to her to succeed in STAP cell research. It is my humble opinion that Riken must create a working environment where female scientists could perform their research with joy and without fear. Japanese science is among the top in the world but it will not be accepted by the world scientific societies if Japanese female scientists are continue to be looked down. Riken is responsible for improving this condition, and so is the government of Japan.

    1. Dear Maxwell, you are fully off topic with your post here. This is a tribute to the great science Dr. Sasai has done during his career. Indeed he has been a great scientist and this is a great loss for the community.

      About the rest of your post. in science there is more than right or wrong, unfortunately there is also fraud and this is the main reason why these two papers were so controversial. Sadly, Ms. Obokata destroyed the future of many good Japanese female scientist by her blatant and short-sighted actions.


  10. Maya Heinert, MD

    Agree that the loss of this brilliant man was in part due to today’s lightening speed judgement within social media and in the news – often without factual basis or true understanding. What a pity, and what a loss to the world.

  11. I wrote this last week via twitter/scoopit:


    Much has been written about the controversy surrounding the publishing of a new methodology for adult cells to acquire pluripotency via STAP reprogramming protocols. However, no one would have believed the latest twist to the saga if it had been suggested as a possibility. Yoshiki Sasai’s death has come as a shock to the stem cell community. It is a sad testimony to the stresses involved in leading the field and a body blow to progress. A brilliant talent has been lost, unnecessarily. The rarefied world of truly breakthrough science and the scientists who devote their lives to the endeavor are few and far between. Japan has its share and Yoshiki Sasai was one of them. His name and reputation in embryology and tissue engineering was known worldwide in the field and beyond. He gave hope to many that one day we will be able to provide solutions to those that are visually impaired and suffer from CNS disorders. Yoshiki Sasai’s science was selected by UCL in London to develop hESC photoreceptor cells and optical tissue sheets. This by itself only scratches the surface of what value his scientific efforts will spawn. When considering the work of the top scientists in the stem cell world I would always include Sasai in that list. He was as a member of a select group that pioneered approaches to solve human disease using man’s most versatile and powerful tool – human embryonic stem cells. His pursuit of in-vitro development of complex tissue systems of the CNS has led the way for many to follow. Science they say is built on the back of peers – Yoshiki Sasai’s science will be remembered as a step up. Condolences. Cheers Michael

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