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Why stem-cell science thrives in Japan

by Rowan Hooper

It’s easy to take for granted the epic scale of what some scientists are attempting these days. When the news broke a couple of weeks ago that Japanese scientists had turned normal cells from a mouse into eggs, and then fertilized them and seen them develop into baby mice, I thought it was pretty cool.

But I wasn’t that surprised.

I knew that Katsuhiko Hayashi — one of the scientists involved — was doing fascinating research on stem cells at Kyoto University, and so this seemed a natural progression for his work to take.

Then I spoke to him and his boss. What they said reminded me that they are attempting to do something that, until recently, would have blown the mind of almost any scientist, philosopher or other kind of intellectual there’s ever been throughout the whole of human history.

Mitinori Saitou, who is head of Hayashi’s lab at the Department of Anatomy and Cell Biology in the Graduate School of Medicine, was highly ambitious from an early age, and became particularly focused when he was doing his PhD as a young man.

“I got interested in germ-cell biology and the regulation of the cell fates,” he told me, “hoping that one day it may be possible to develop a methodology to control cellular fate at will.”

To control fate: It’s like something out of a Greek myth.

Hayashi too has long been interested in pushing the boundaries of human reproduction. “When I was child, there was news about animal cloning,” he told me. “That was one reason why I got interested in this field.”

The atmosphere for research in Japan allows ambitions such as these to flourish.

“Japanese people like very much to produce something, and to manipulate tiny things,” Hayashi told me during an e-mail exchange. “Another reason is that we are relatively free to use experimental animals, compared to scientists in Europe,” he added.

So there you have it — some of the reasons Japan is a world leader in stem-cell research.

And within Japan, Kyoto University is perhaps the most advanced in this field — while in that university, 50-year-old Shinya Yamanaka is the most revered.

In 2006, Yamanaka — who has worked at the Gladstone Institute in San Francisco and Nara Institute of Science and Technology in Japan, and who is currently still affiliated with the California institute — showed that a surprisingly simple recipe could turn mouse skin cells back into primitive cells, which in turn could be prodded into different kinds of mature cells.

The following year, he repeated his work with human cells. In fact, he did no less than show that it is possible to transform adult skin cells into cells similar to human embryonic stem cells — cells, in other words, that were able to develop into any kind of cell in the body.

His work was widely tipped to win him the Nobel Prize in Physiology or Medicine this year — an honor he was indeed awarded this week along with Cambridge University researcher John Gurdon, 79.

In announcing the $1.2 million prize on Monday, the Nobel committee at Stockholm’s Karolinska Institute said the two scientists’ work has “revolutionized our understanding of how cells and organisms develop.”

Meanwhile, when Hayashi’s work was published two weeks ago, and was then picked up by news organizations around the world, most articles emphasized that it could one day allow women to have babies at any age.

In an AP story carried by The Japan Times, for example, the report began: “If successfully applied to humans (the technique) could someday allow women to stop worrying about the ticking of their biological clocks and perhaps even help couples create ‘designer babies.’ “

Hayashi himself played down this angle. However, I did ask him about ways his research might help to improve human reproduction in the future.

“One way is by the identification of genes and factors involved in reproduction. This will lead to the discovery of the causes of infertility and the discovery of drugs (to treat it). The other is, of course, by making human gametes in vitro,” he explained.

Hayashi and colleagues have already made mouse gametes (cells that fuse with others during fertilization [conception], i.e., an ovum and sperm in humans and mice) in the test tube — this was the work that was published two weeks ago in the journal Science (DOI: 10.1126/science.1226889).

Before they move on to human cells, Hayashi said there needs to be careful discussion of the ethics involved in the research. Much more basic research is needed too, as we don’t yet know in detail how human eggs form.

Japan’s low birthrate is a concern to Hayashi. “It is a very serious problem,” he said, pointing out that it was caused by many factors, some societal, with the most critical one being education. Japanese people, he said, are not well informed about the ticking biological clock: They don’t realize that women’s fertility starts to decline after the age of about 40.

“I had a chance to talk with an embryologist working in an ART (Assisted Reproductive Therapy) clinic,” he said in our e-mail exchange. “She told me that people know when they can start reproduction, but do not know when reproductive potential ceases.”

Better than turning skin cells into eggs, said Hayashi, would be to educate people. “Talking about sex is still taboo in Japan. To increase the birth rate, improving education is much more efficient than developing reproductive-science technology.”

It’s a point worth emphasizing. It might seem odd to outsiders that sex is taboo in Japan. This is a country, after all, that is famous for its huge range of bizarre pornography readily available at seemingly every turn. But Japanese people are in some ways inhibited, a bookstore manager in Tokyo once told me.

We were talking about the sales of my first book, translated into Japanese and titled — at the suggestion of the Japanese publisher — “Nou to Sekkusu no Seibutsugaku (Evolution, Sex and the Brain).”

Japanese people are ashamed to be seen in the bookstore holding a book bearing the word “sex” on the cover, the bookstore manager explained. I learned the lesson — and my second book had a different title.

But back to Hayashi and Yamanaka’s work. It’s a reminder that we are living in a golden period of scientific discovery, one in which we can even manipulate “fate.”

It’s also a timely reminder that even in one of the most scientifically advanced countries in the world, basic education and communication could be a whole lot better.

Rowan Hooper (@rowhoop on Twitter) is the News Editor of London-based New Scientist magazine. The second volume of Natural Selections columns translated into Japanese is published by Shinchosha at ¥1,500. The title is “Hito wa Ima mo Shinka Shiteru (The Evolving Human).”