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BLOG biotech : Jan 24, 2012
The Human Roots of Stem Cells
If banal remarks like "funny weather we've been having" fail to impress, there's a new truism in town: "Stem cells are a popular topic these days." Human embryonic stem cell (hESC) research has dominated bioethics discussions for the past two decades, but the underlying science has been making people uncomfortable for much longer.
It all started with in vitro fertilization (IVF), developed in the late 1970s by Patrick Steptoe and Robert Edwards. There were fears of deformed babies, "playing God," and the prospect of unrelenting failure. But research continued, even as funding requests were rejected by U.K.'s Medical Research Council. The failures continued for several years—ectopic pregnancies, miscarriages, and premature births—but eventually there was a success, followed by another, and another, until the number of successes totaled some four million babies born with IVF.
The controversy never ceased, but new developments took the forefront: The growing supply of leftover embryos from IVF was being considered for research instead of destruction. In response, the 1996 Dickey-Wicker amendment was passed, banning federal funding for research involving the destruction of embryos. Two years later, Dr. James Thomson managed to create the first hESC line with funding from Geron. It was a landmark discovery, both scientifically and politically, and it circumvented the funding restriction by separating the embryo-destroying step from hESC research. George W. Bush's executive order in 2001 reestablished those limitations, and President Obama's executive order removed them, but the amendment still remains, and continued lawsuits and appeals threaten public funding for hESC research.
The case in Europe isn't any better. Last year an EU judgment disallowed patenting of products based on embryo-destroying research. Like Dickey-Wicker, there's a technology to circumvent it: Advanced Cell Technologies has announced that their nondestructive "single-blastomere" hESC line method doesn't fall under this definition. Of course, it's an arbitrary distinction—it leaves behind a viable embryo, but what are the odds that it will see a fate different from all the other excess IVF embryos?
France, in its 2011 bioethics law, allows hESC lines derived from IVF but bans implantation of research embryos; while ACT may not be subject to such laws it also would be unlikely to find a willing surrogate. Even Senomyx received criticism for using HEK cell lines to express flavor receptors for food additive testing; the cell line is derived from tissue excised from an aborted fetus over 30 years ago. ACT's nondestructive hESC method may be a breakthrough, but to their opponents it will likely seem like more of the same.
Revolutionary Business As Usual
Scientific progress is inherently disruptive: In the process of revising our understanding of the world and the way we live in that world, the status quo must be altered. Many experiments evoke everything from fear (black holes stemming from the Large Hadron Collider) to disgust (hybrid chimaeras and genetically engineered organisms).
Stem cell research has already demonstrated that hESCs are extremely useful as a reference by which other cells can be judged—comparisons between induced pluripotent stem cells and hESCs help identify the changes that take place during induction of pluripotence. Also, the "aging" via DNA methylation in immortal hESC lines serves as a useful point of inquiry, identifying some of the changes that affect even immortal cells over several generations of cell culture. Alternative sources of cells—amniotic, adult, and induced pluripotent—are able to supplement, not supersede them.
There are few hESC products today; after Geron's departure, only ACT's clinical trial remains. However, the continuing use of hESCs even in light of shaky funding and perennial legal threats is testament to their value as indispensable research tools. The roadblocks to research are quick to appear and slow to dissipate, but they are inevitably overcome. Though some segments of the public will never come to terms with IVF, the tireless efforts of a physiologist and an obstetrician helped IVF bloom into a solution for millions of infertile couples. Facing a similar landscape, stem cell research has its roots tapped into the same reservoir of scientific curiosity and hope. We might yet see the field blossom into replacement organs, diagnostics, and cures.
Just one thing: Deep roots or not, plants usually grow faster with a little water and sunlight.
Comparison of hESC and iPSC in scientific literature
(Briefly: ~3:1 ratio of hESC:iPSC publications, hESCs and iPSCs often used together)
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