 |
|
|
|
|
Asking the right questions about fertility clinics
"I believe there are some wonderful opportunities for adult stem cell research," President George W. Bush told reporters when first he was asked about this touchy subject. Recently, House Majority Whip Tom DeLay of Texas, a prominent foe of embryonic stem cells research, declared that he supports "stem cell research--research that is ethical...the stem cell research I am referring to is derived from adults." Catholics, evangelicals, and others who oppose embryonic stem cell research--and are urging Bush to deny any federal support for same--point to adult stem cells as the resolution of the issue.
This sounds great, but adult stem cells may not necessarily solve the moral issue at all. In fact, they could make it more troubling, because the one technique so far known to produce significant numbers of such cells functions by creating an entirely new class of biological object--the artificial embryo. Late yesterday (July 11), Advanced Cell Technology (ACT) of Massachusetts, the leader in adult stem cell research, announced it had deliberately created artificial embryos and then cloned them as sources of stem cells.
Initial media attention to this announcement--the second big stem cells announcement in as many days, following the news that the Jones Institute fertility clinic had created natural embryos solely as stem cell sources--was garbled. Initial reports fixated on the word "cloned," because ACT duplicated the embryos it made. But cloning at the cellular level is routine in medical research--and in our bodies. It's the phrase "artificial embryo" that should have caught everyone's eyes.
In a 1999 interview, James Thomson of the University of Wisconsin, the first scientist to isolate human embryonic stem cells, told me why the adult stem cells technique was troubling: "It would solve one ethical problem but it might create another, because it might lead to a totally artificial kind of viable embryo."
This is why the adult-derived stem cell may not necessarily be the solution to stem cell controversies. It may open the door to things even spookier than what opponents worry about now.
|
|
|
|
|
By Gary Bauer
Here's the background. Stem cells are uniquely flexible structures with the ability to become any kind of cells. Until the 1990s, researchers believed they existed only very early in mammalian development and could undergo only one kind of "differentiation"--from stem cell into heart cell or muscle cell and so on. Then researchers discovered they could chemically trick stem cells into reproducing more stem cells, and after that, induce them to make new tissue. This held out the hope that new, healthy tissues derived from stem cells might offer cures for diabetes, Parkinson's, and many degenerative illnesses.
In 1998, Thomson successfully isolated stem cells from a few human embryos that had been discarded by a fertility clinic and induced the cells to reproduce themselves. A few months later, a researcher at Johns Hopkins University did the same, using stem cells extracted from an aborted fetus.
The Catholic Church, some evangelicals, and others have declared strong opposition to any research use of embryos, arguing that an embryo is a human life and thus inviolable. Equally influential lobbies favor embryonic stem cell research, as the potential to cure disease is so high. Development of medical therapies based on stem cells has been held back by rules that forbid researchers from using federal funds to work with stem cells derived from embryos. Bush must decide whether to uphold or alter this ban.
Faced with the moral dilemmas of using embryos as stem cell sources, some researchers have searched for stem cells in other tissues. Cells taken from the brains of adult mice have been chemically tricked into becoming mouse muscle; Yale University researchers have induced mouse bone marrow cells to turn into several types of mouse cells, essentially mimicking what stem cells do.
One research physician has claimed success in using stem cells from umbilical blood to treat a person with bone marrow disease. In recent months, private researchers in California and New Jersey have claimed to have found stem cells in fat tissue and in placental blood, but mainstream scientists are extremely dubious of both claims: There appeared to be significant errors in the fat cells study, while the placental blood study has not yet been published in any journal, usually a sign there's a problem.
Generally, attempts to take stem cells directly from adult or non-embryonic tissue foundered for two reasons. First, adult-derived stem cells fail to be "vigorous"--they don't act young and wholly healthy, for reasons unknown. Second, adult-derived stem cells won't reproduce themselves much, so the supply is small. Embryonic stem cells, in contrast, are vigorous and will copy themselves seemingly indefinitely.
Enter Advanced Cell Technology. Three years ago, the company announced it had drawn some cells from a grown man and chemically tricked them into turning back into young stem cells. Biologists were stunned; most considered reverse differentiation physically impossible. Many university-based researchers expressed skepticism about whether the ACT discovery would really work. Opponents of embryonic stem cell research praised the adult-cell announcement, which seemed to mean that embryos would no longer be needed for the manufacture of stem cells. As a bonus, replacement tissues for a disease victim might be cultured from his or her own cells, ensuring a genetic match.
But as researchers gradually learned what ACT was up to, they realized that moral questions would not necessarily be solved. What ACT did was remove cells from an adult and then transfer them into the nucleus of a human egg from a donor. Through some process that is not yet understood, being surrounded by an egg made the cells "youthful" again, returning them to the state of being true stem cells. But what exists when ACT does the procedure is an artificial embryo. If planted into a woman's womb (ACT says it will not do this), the artificial embryo would probably become a person.
This adult stem cell technique might solve the current version of the controversy. Fertility-clinic couples would never be involved; no embryo initially created for fertility purposes would be used at any stage. There would be no sense that researchers were destroying a potential all-new life that two parents once desired, even if that potential life was no longer desired and now scheduled to be discarded by the fertility clinic.
But the artificial embryo would still be an embryo, capable of becoming a person. This key point is being missed in coverage of ACT's announcement that it is pursuing adult stem cells creation on a major scale. The company has signed up volunteers to provide eggs for the stem cells intermediary phase; the women know it's stem cell research and give informed consent, but they may not understand an artificial embryo is being created, since hardly anyone seems to have noticed this.
If an embryo is a human life, wouldn't an artificial embryo be a life too? When in vitro embryos were first created in fertility clinics about two decades ago, evangelicals, Catholics, and others quickly came to feel that such embryos were sacred life, even if they came about in a way nature did not originate. What's the difference between that and all-artificial?
And while the media fixate on the word "cloning" in the ACT announcement--that the artificial embryos would be cloned at the embryo level to increase the supply of stem cells--there is a missed cloning aspect to this work. What the artificial embryo contains is only DNA from the adult (the woman egg donor's DNA has been removed). That means if the artificial embryo were implanted and grew into a person, it would be a genetic copy of the adult from whom the cells were taken: a clone.
|
|
|
|
|
Perhaps a non-embryonic adult stem cell process will be devised. Based on what's possible now, to decide that adult stem cells obtainable mainly from artificial embryos don't pose the moral quandaries of embryonic stem cells, you must be willing to say that artificially made embryos are not life in the way that natural embryos are. And you must make a judgment about cloning. You must be willing to posit that, although Person No. 1 is fully human, a genetically copied Person No. 1A would not be fully human. This seems the first step down the road to the science-fiction nightmare of living organic beings who can be misused because society does not consider them truly "real."
Stem cells hold enormous promise, and it is a life-affirming promise--the promise of curing disease and sustaining life. But barring the breakthrough that allows adult stem cells to be cultured without any embryonic stage, there may be no way to reach this promise without very discomforting decisions. The first successful technique for using adult cells to create stem cells is, as it stands now, no panacea.
