The End of Embryonic Stem Cells
British researcher John B. Gurdon and Shinya Yamanaka of Japan shared the 2012 Nobel Prize in medicine last week "for the discovery that mature cells can be reprogrammed to become pluripotent," meaning they can be developed into a number of specialized cells.
The scientists are a generation apart, with Gurdon making his initial discovery that the DNA from specialized cells of frogs could be used for cloning in 1962 -- the year Yamanaka was born. More than forty years later, Yamanaka, building on Gurdon's research, discovered a method for reprogramming mature cells in mice to become immature stem cells capable of developing into any type of specialized cell.
Yamanaka's "simple" method includes introducing a combination of four genes together into mature cells from connective tissue. These cells became pluripotent stem cells, capable of developing "into mature cells types such as fibroblasts, nerve cells and gut cells."
"These groundbreaking discoveries have completely changed our view of the development and cellular specialization...We now understand that the mature cell does not have to be confined forever to its specialized state," wrote the Nobel Assembly at Karolinska Institute. Yamanaka's research was published in 2006, and immediately recognized as groundbreaking, but as is typical the Nobel Assembly held off on awarding the duo its prize to ensure the science stood the test of time.
Medicine is abuzz about the broad implications of Gurdon and Yamanaka's work. Their research will hopefully pave the way for innovative treatments for some of the most untreatable diseases. This technology may also assist infertile women and help gay parents have children made from both their genetic material.
What's most astounding is Yamanaka's motivation for his world-altering research. Stem cell research has always been a field plagued by endless controversy over the ethical treatment of human embryos. In human embryonic stem cell research, the embryo is destroyed when the cells are extracted. This has led to the familiar debate over when life begins, and whether the benefits of embryonic stem cell research outweighed their human toll.
Yamanaka's research allows stem cells to be created without the use of embryos, from already existing mature cells, sidestepping the embryonic stem cell debate entirely. If the Assembly also gave an award for a Nobel Prize in ethics, Yamanaka might well have been a double recipient.
It wasn't by accident that his research led to this development. In fact, he envisioned this project after visiting a friend's fertility clinic where he viewed an embryo through a microscope. A father of two, Yamanaka reflected, "I thought the differences are very small between these small cells, embryos, and my daughters. I saw that if we could make pluripotent stem cells without using human embryos, that would be ideal. That's the moment I thought about this project." Yamanaka's ingenuity helped him find a way to advance the cause of medical research without abandoning his moral compass.
Though his findings will no doubt pave the way for an embryo-free stem cell research field, his methods were not as squeaky clean. In Yamanaka's initial research, his team used the stem cells of aborted fetuses and some embryonic stem cells. Yamanaka also attended a 2009 ceremony to support President Obama's lifting of the embryonic stem cell ban. "Patients' lives are more important than embryos," but "I do want to avoid the use of embryos if possible," he told the New Scientist in 2007.
Yamanaka's soft commitment is still something to be thankful for today as his research will pave the way for the end of the embryonic stem cell era. "The initial insight unfortunately involved tainted material, but it gives way to an application of that knowledge which can be perfectly morally licit," said Father Thomas Berg, Professor of Moral Theology at St. Joseph's Seminary in Yonkers, N.Y., in an interview with the Catholic News Agency.
Suffice to say that Yamanaks and Father Berg might disagree on the age old question of whether an end can ever be justified by sinful means. Nonetheless, says Father Berg, Yamanaka was "motivated by reflection on the fact that his own daughters were once human embryos" and "that is something to be thankful to God for."
While Yamanaka seems to have closed one controversial chapter in scientific research, he may well have paved the way for the resurgence of another: human cloning. His research brings us ever closer to that feat, as demonstrated by Ian Wilmut, the scientist who brought us Dolly the cloned sheep, abandoning his methods in favor of Yamanaka's. Most recently, last week researchers in Japan used Yamanaka's method to create baby mice from the skin cells of existing mice.
These issues will have to be grappled with as they come along. But for now it appears regenerative medical research can progress while preserving the sanctity of life. For once, scientists and the faithful can have their cake and eat it too.