What if someone dear to you had a condition for which there was no existing cure? There would be a feeling of desperation to find a remedy. This is what has driven me to become a scientist — the desire to challenge paradigms and create new prototypes.

Credit: Cincinnati Children’s Hospital Medical Center

I was born into a working-class family in Yokohama, Japan. When I was in elementary school, my father had a pontine stroke, which can be life-threatening. But, as he happened to be near a hospital when the stroke happened, he miraculously recovered and was eventually able to go back to work. As a young child, I was awed by the power of medicine.

Later, I decided to enter medical school at my ‘home’ university, Yokohama City University. In my early years in medical school, I was bothered by the fact that most doctors did not deviate from standard, accepted protocols. I started volunteering in a laboratory focused on stem cells every night after my classes for four years. I learned lab skills from many people and was excited when I identified in the human and mouse ear a progenitor population specific to elastic cartilage tissue.

While on a two-month exchange as a medical student in a surgical division at Columbia University, one of the world’s largest liver transplant centers, I was struck forcibly by patients dying from liver failure owing to the organ shortage crisis. I was faced with many such patients, and my aspiration moved towards the establishment of an alternative approach to transplantation. After obtaining my MD, I accepted a research position at Yokohama City University in Japan and decided to initiate studies on the then-emerging field of induced pluripotent stem cells, which are adult cells reprogrammed to behave like embryonic stem cells. In the embryo, liver-forming cells rely on an elaborate communication system involving nearby cells to develop into the three-dimensional organ, and I suspected that these supportive cells would also be necessary to develop a liver in a dish. In 2011, I developed liver-cell precursors, or hepatoblasts mixed with mesenchymal and endothelial cells, almost serendipitously. I used a petri dish that was not meant for cell culture, but found a surprising degree of self-organization among the precursors into miniature 3D tissues. I still remember coming into the lab and visualizing these mind-blowing spheroid formations while my less-than-impressed co-workers thought these structures were ‘contamination’. Fortunately, I proved that these formations were not a contamination issue, and thus my team managed to create ‘miniature livers’ (or organoids) that resemble the liver of a six-week-old human embryo.

In 2015, at age 28, I became an assistant professor (currently an associate director of Center of Stem Cell and Organoid Medicine) at Cincinnati Children’s Hospital Medical Center, and, in 2018, I accepted a joint position as a full professor at Tokyo Medical and Dental University. In 2017, I also started a unit focused on highly translational research at Takeda Pharmaceuticals in partnership with Kyoto University (Takeda-Center for iPS Cell Research and Application, or T-CiRA) under Nobel laureate Dr Shinya Yamanaka’s directorship, for organoid-based drug safety and development applications. These three labs operate with a unified aim of bringing a difference to current medical care by fully utilizing organoids for real-world medical applications, namely organoid medicine.

Another of my life’s works is to employ design and art in medicine. After 8 years of work with artistic creators, most of whom are in the advertising field, on design projects that ranged from fashion to space design to promote well-being, I recently founded a state-of-the-art design center, the YCU-Communication Design Center (YCU-CDC) (http://y-cdc.org/portfolios/), at my alma mater medical school. Recruited faculty and staff include designers, copywriters, web editors and educators, and we locally collaborate with design firms and advertising agencies.

The advice I give to those entering research is to (1) constantly ideate and share your thoughts with others, (2) interact with people with extremely different backgrounds and expertise, and (3) make a conscious, risky decision that is unique to human beings.