A scientific challenge which began a decade or so ago has finally been met: human stem cells have been cloned using the same cloning technique used to create Dolly the Sheep. Unfortunately, this scientifically important moment has become mired in confusion, hype, and a looming ethical firestorm.
The basics: Last week in the journal Cell, a team of scientists from Oregon Health and Science University declared their success in harvesting embryonic stem cells from human embryos cloned using somatic cell nuclear transfer. This technique involves implanting the nucleus of a patient’s cell into a donor egg cell whose nucleus has been removed, creating embryos (and therefore stem cells) that are a genetic match for the patient. A South Korean scientist had claimed success in 2004 but was revealed to be a fraud.
Reactions have been mixed.
As The Boston Globe’s Carolyn Johnson points out, “the discovery would no doubt be a bigger deal if in 2007, scientists had not discovered that there was a different, simpler way to create stem cells.” This simpler way is the “reprogramming” of skin cells by flipping a genetic switch to trick them into becoming embryonic-like stem cells. These are induced pluripotent stem cells.
Induced pluripotent stem cells (IPSC) sidestep many of the ethical concerns surrounding the cloning of stem cells, and the developers won the Nobel Prize in 2012.
By and large, cloning has fallen out of favor in the scientific community, but it does offer at least once advantage: the reprogramming of skin cells does not affect the genetic material contained within the cell’s mitochondria. If the patient has a mitochondrial disorder—which can result in diabetes mellitus and deafness, multiple sclerosis, and dementia—then stem cells made from their skin will also have the genes that cause this disorder.
The cloning technique, by starting with a completely healthy donor egg, creates stem cells with healthy mitochondria that could, in theory, be used to help correct the cause of these mitochondrial disorders. But this is a purely hypothetical application of the new technique, and it alone hardly qualifies this paper for some of the outsized extrapolations it has received.
Much of the blame for the more triumphant headlines might be traced back to Cell’s own press release, which seems to have overreached dramatically with the title “Major advance provides human embryonic stem cells for personalized medicine.” The Knight Science Journalism Tracker and HealthNewsReview.org both offer dissections of the disparate coverage, which varied from breathless (Fox News: “In medical breakthrough, scientists convert human skin cells into embryonic stem cells”) to tempered (Boston Globe: “Scientists clone human embryonic stem cells: feat but now seen as minor advance”).
Much of the hype hinges on two points: (1) that this is the first successful cloning of a human and (2) that this procedure could be a medical breakthrough. Both premises are contestable at best.
This is the first ever successful human cloning, but it isn’t: the scientists were only interested in cloning humans insofar as they could get embryos to develop enough to harvest stem cells from. Whether or not this technique could generate a healthy human clone, a Dolly the Human, is both a moot point to the researchers and a total unknown.
Shoukrat Mitalipov—who led the research at Oregon Health and Science University—told the Associated Press that he does not believe that the cloned embryos be developed into human babies.
The idea that this work might be a “breakthrough” is hectored by the fact the technique is difficult and far from ready for medical rollout, relies on ethically fraught egg donations, and may well remain outpaced and outshone by induced stem cell techniques. As Rudolf Jaenisch, biologist at MIT’s Whitehead Institute, told The Washington Post: “An outstanding issue of whether it [somatic cell nuclear transfer] would work in humans has been resolved,” but the feat “has no clinical relevance.”
Of course, the ethical tinder surrounding the idea of human clones is very, very combustible. This paper has provided more than enough spark to start sending up smoke from watchdogs like the Center for Genetics and Society. Despite Mitalipov’s doubts about and disinterest in the production of cloned human babies, CGS executive director Marcy Damovsky still had no trouble telling the Associated Press that this paper is a perfect excuse for the federal government to ban the use of cloning for reproduction.
Since the news broke, the Center for Bioethics and Culture Network has been in a near-frenzy, starting with the headlines “Human cloning is here!” and “Let the cloning obfuscation begin” and publishing a series of highly critical, emotionally charged stories decrying the “junk biology” behind “biotech types” and media that dare to make an ethical distinction between human “cloning” that cannot or will not produce a baby the production of cloned children.
Catholic groups, some of the loudest opponents to embryonic stem cell research, have responded as expected. Whether Reverend Tad Pcholczyk at the National Catholic Bioethics Center, the Conference on Catholic Bishops, or Cardinal Sean O’Malley of Boston—all who have been asked have reaffirmed the Church’s opposition to using “early human beings” to grow stem cells.
But it’s not only groups ideologically convinced (and chomping at the bit for any excuse to remind us) that human cloning would be an ethical disaster who have been fanning the flames. Even the New York Times invoked the specter of cloned babies:
Scientists have finally succeeded in using cloning to create human embryonic stem cells, a step toward developing replacement tissue to treat diseases but one that might also hasten the day when it will be possible to create cloned babies.
Whether not this turns into a full on bioethics wildfire remains to be seen, but you can bet that those with an interest are now primed and ready should anyone take the techniques used by Mitalipov and his colleagues and attempt to use them to develop cloned human babies.
Despite the generally subdued and skeptical reaction of the scientific community, those with an interest in science should brace themselves for the debates that are very likely to ensue. In the meantime, Carolyn Johnson offers a poetic punctuation mark on the scientific context of this ethically charged achievement:
And so a major quest in science comes to an end, in a saga that shows how a major scientific quest can fall to the wayside with advances in technology and knowledge. Moreover, grand scientific missions are often just the first step toward transforming human health. Even if the technique turns out to have some advantage over reprogramming, what lies ahead is the long road toward taking a technique and turning it into something that could be a useful therapy.
Kenrick Vezina is Senior Editor for the Genetic Literacy Project and a freelance science writer and educator based in the Greater Boston area. He has an M.S. in science writing from MIT.
- “Cloning, Stem Cells Long Mired In Legislative Gridlock,” NPR
- “Human embryonic stem cells are cloned,” USA Today