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A revolutionary stem-cell therapy must proceed responsibly to achieve its full potential
Shinya Yamanaka in 2012, the year he won a share of a Nobel prize.Credit: Aflo/Shutterstock
Shinya Yamanaka doesn’t see himself as a celebrity. But people do recognize the stem-cell researcher when he’s out for a run, often while training for a marathon, on the streets of Kyoto, Japan.
Many of them call out words of encouragement. Some tell him that they hope his research will lead to cures for family members who are battling severe illnesses. “I feel deeply humbled and grateful,” says Yamanaka, who splits his time between Kyoto University and the Gladstone Institutes in San Francisco, California.
Some of the hoped-for cures could be nearing reality. It has been quite a wait — 20 years, in fact — since the paper1 that shook biomedical research and won Yamanaka a share of the 2012 Nobel Prize in Physiology or Medicine. In it, he and his colleague, Kazutoshi Takahashi, also at Kyoto University, unveiled a way to turn back time in adult mouse cells, erasing their identity and reprogramming them to an embryonic-like state — all by switching on just four genes.
That discovery opened up a possible way to treat disease. If those cells, called induced pluripotent stem (iPS) cells, could be coaxed to take on fresh identities, they might provide a source of healthy tissue, fashioned from a person’s own cells, that could repair diseased or damaged organs. Earlier this year, the first such therapies — one for Parkinson’s disease and the other for heart failure — received conditional approval in Japan2. Clinical trials of iPS-cell therapies are under way around the world.
The stem-cell field now stands at a turning point. As more therapies are rolled out, the goal of researchers, companies and regulators must be to ensure that these treatments are developed responsibly, and that they will be available to all who need them.
Japan’s big bet on stem-cell therapies might soon pay off with medical breakthroughs
Before the landmark 2006 paper in Cell, Yamanaka’s colleagues sometimes questioned the scientific path he was forging. They would tell him: “Those mouse cells may be interesting, but you should do something more closely related to human disease and human medicine,” as Yamanaka recalled during his Nobel prize lecture.
But his discovery was soon replicated in human cells3,4. After that, researchers had to work out how to induce iPS cells to acquire identities that could be useful for studying and treating disease.
Deepak Srivastava, a cardiologist and stem-cell researcher at the Gladstone Institutes, still remembers the joy he felt when he saw that his laboratory had finally generated heart cells from iPS cells. Even so, only about 1% of the iPS cells had adopted that new identity, he says. It would take more years of work before the lab could get 90% or more of their stem cells to become heart cells — enough for them to spontaneously beat in unison, generating waves in the culture medium.