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the Stem Cell Page time and ignorance are the enemies |
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It’s official: Jim Talent advocates and opposes cloning |
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May 5, 2006
To clone or not to clone?
That is the question Senator Jim Talent (R - MO) will ultimately face because at present he both advocates it and opposes it. Confused? Few are aware that Talent plays it both ways, apparently not even Talent himself.
Until recently, most people thought of cloning as the manufacture of duplicate living beings like the Stepford Wives. Science fiction has long envisioned this phenomenon, and many stories were written and films made to frighten the bejeebies out of us. To that extent, they were successful at ingraining a fear that rushed over us as we heard the word “cloning.”
But removed from the literary and cinematic contexts, cloning comes in two real life flavors:
1. Reproductive cloning
To date this has never been done with humans because virtually all scientists abhor the thought of human reproductive cloning. However, it has been done with other mammals. Dolly the sheep was the world’s first and most famous clone. Dogs and cattle have also been cloned. Just a few days ago, the Chinese cloned a calf that is touted as genetically resistant to mad cow disease. Of course, this will require much study and testing to confirm. The fear of reproductive cloning is that the technique applied to produce cloned mammals, might one day be applied to create a cloned human baby (“human cloning”).
2. Therapeutic cloning
This is the kind about which most people are just now learning. This variety of cloning can help us understand how diseases develop, invent new medicines and create stem cells that may lead to therapies, treatments and cures specifically tailored to individual patients.
For some, the distinction becomes blurred or even nullified because both forms would necessarily begin with the same process. The process is called Nuclear Transfer. It begins with a donated egg. A woman who elects to donate eggs receives medications for several weeks causing hyper-ovulation. The eggs are then harvested via a minor surgical procedure. This is the technique used by fertility clinics for in vitro fertilization (“IVF”).
But instead of fertilizing the egg with sperm, as would be done in IVF, the nucleus of the egg is removed. Since the donor’s genetic code (DNA) is located in the removed nucleus, the egg becomes a hollow vessel of nutrients, no longer genetically associated with the egg donor.
The next step is taking a patient’s somatic cell – virtually any cell from a patient’s body (usually skin cells) – and transferring that cell’s nucleus into the hollowed egg. At this point, the egg contains the DNA only of the patient. This process is called Somatic Cell Nuclear Transfer or SCNT.
The egg is placed into a Petri dish with a “nutrient cocktail” and an electric charge is introduced, which stimulates the egg to divide and become a ‘pseudo-blastocyst.’ This is where the similarity between reproductive and therapeutic cloning ends.
In human reproductive cloning, the pseudo-blastocyst would [theoretically] be implanted in a woman’s uterus and ultimately a cloned baby would be born. But scientists have learned that there are significant differences between real blastocysts (from the union of sperm and egg) and cloned pseudo-blastocysts. Aside from noticeable differences in gene expression in the laboratory, tests in animals demonstrate that naturally achieved blastocysts implant far more readily in a uterus than pseudo-blastocysts. For instance, it took more than 270 attempts before implantation with a pseudo-blastocyst proved successful in creating Dolly the sheep.
In the case of therapeutic cloning, the pseudo-blastocysts never leave the Petri dish. Once they reach the stage of creating stem cells, the stem cells are isolated and allowed to continue to “clone” themselves. Their Petri dishes become little stem cell factories, indefinitely churning out more and more stem cells.
So what’s the problem with that?
Although there is no union of sperm and egg, some purport that the pseudo-blastocysts constitute human life. For them, any cloning (therapeutic or otherwise) is wrong.
This is where Jim Talent gets stuck. He wants very much to appease his political base – the religious right – but still wants to appear to support research which might lead to curing millions of Americans.
Talent had co-sponsored a bill introduced by Senator Brownback (R - Kansas) that would not only ban, but criminalize cloning. All cloning, therapeutic or otherwise. Had the bill passed, the penalties would have indeed been serious. Anyone who engaged in the research, prescribed a treatment, administered a therapy or received a cure would be subject to felony charges, facing long prison terms and stiff fines.
The proposed ban would also extended beyond our borders. If you were the parent of a seriously ill child and took your child for treatment in a foreign country where such treatments were legal, you’d still be subject to arrest and prosecution upon your return. That’s pretty extreme.
In an election year, looking like an extremist generally garners votes only from extremists and that’s not politically healthy. Talent needed a way to bow out gracefully or at least with some political dignity. The course he chose - running for cover - proved neither graceful nor dignified.
It was more like dropping a bomb. He recanted from his co-sponsorship of Brownback’s bill during the course of a thirty minute speech on the Senate floor. Wanting to appear at the cutting edge of stem cell science, he touted something of which most of his colleagues and constituents had never heard: Altered Nuclear Transfer or “ANT.”
“ANT,” he proclaimed, “signals the end of ethical dilemmas in this type of research.” He went on to say, “If we can get the stem cells without the cloning, we render the current controversy scientifically obsolete.”
Not so fast, Senator. ANT is actually a subset of SCNT - same donated egg, same somatic cell and same transfer of the nucleus. The difference is that nucleus from the somatic cell is genetically “pre-treated” so that it won’t implant. What Talent may not have realized is that it’s still a nuclear transfer process and, therefore, cloning. But he felt comfortable claiming that the resultant cell could never be implanted, could never become a baby, and therefore he proclaimed this process as his stem cell source of choice.
Talent apparently only read the Cliffs Notes on ANT. Well, maybe he just scanned them. All he seemed to know was that the ANT-derived pseudo-blastocysts could be created so as not to become babies. They just lay there making stem cells. Chemically treat them to inhibit their ability to implant, he figured, and everyone should be pleased.
So who did he please? No one.
So called pro-lifers focused on his withdrawal from the Brownback bill. Larry Weber, executive director of the Missouri Catholic Conference, noted the disappointment from the right. “There’s been a lot of support for Jim Talent from the pro-life community. Today he stepped off that platform. At this point, it’s essentially vacant with respect to the U.S. Senate election. His candidacy gave pro-life voters something they could gravitate towards. Unfortunately, it’s just not there any more.”
Nor did the medical research community rally to his side. Dr. Steven Teitelbaum, a physician/scientist at the Washington University School of Medicine noted that ANT had never even been attempted with human eggs. “There is no evidence this will work in people,” he said.
Moreover, there are two notable flaws in Talent’s hypothesis which void his political conclusion:
1. His advocacy of ANT shifts the “what constitutes life” criterion from union of sperm and egg (or in this case pseudo-blastocysts created without sperm) to implantation - the very argument made by the pro-embryonic stem cell camp.
2. Leaving unmodified SCNT-derived cells in their Petri dishes is just as effective barrier to implantation as modifying the cells, so why bother with the genetic mutation?
Thus, Dr. Teitelbaum characterizes ANT as “a distraction.”
Second, as pointed out to me by Dr. F. Patrick Ross, a pathologist from Washington University, the ANT process is reversible. The introduction of a simple virus can switch the implantation capability back on. [This is not theoretical. It’s been done with mice.] So, just because stem cells come from a pseudo-blastocyst that is unable to implant, does not mean the pseudo-blastocyst lacks the potential to implant. “Think of it as creating a handicapped, but curable cluster of cells,” Ross explains.
It is well known by engineers that designs incorporating fewer moving parts generally make things run better because there’s less to break. So it is with ANT. All the switching on and off of the genes complicates the process, allowing more opportunity for something to go wrong. That’s why even though scientists know about ANT, only a relative few seem anxious to pursue it.
Talent might argue that the ANT resultant cells are not really clones, but scientists say otherwise. Alexander Meissner and Rudolph Jaenisch of MIT’s Whitehead Institute collaborated in a study of ANT and its reversal in those mouse pseudo-blastocysts. In their paper, published in the January 12, 2006 edition of Nature, they make no bones about it when they state, “…all nuclear transfer ES cells are clonal…”
Senator Talent must have overlooked that part. Perhaps he also missed the part about the ability to reverse the genetic alteration, re-establishing the ability to implant. More likely all of this is simply beyond the realm of his chosen field of endeavor. After all, he’s neither scientist nor medical practitioner. He’s a politician.
Politicians make their reputations and careers not on their medical research knowledge, but rather on their politics. Talent for months refused to comment on perhaps the most paramount issue in the upcoming Missouri election: the Missouri Stem Cell Research and Cures Initiative. He remained in “dark mode” until nearly 300,000 petition signatures were submitted to the Secretary of State for certification. Well, 288,991 to be exact; twice the number required to ensure a place on the ballot and delivered ahead of schedule. Once submitted, Talent finally spoke - in opposition. And what was his stated reason? The measure would protect cloning and he’s always been against cloning.
That leaves Talent with a monumental problem. He advocates ANT which, though perhaps unbeknownst to him, is cloning. This should prompt voters to ask the greater questions:
- Why do politicians like Senator Talent believe they are better suited than scientists to direct and regulate science?
- What qualifies politicians to countermand our medical community’s efforts to seek, create and dispense medical care and treatment?
I have yet to meet the mother of a child running a high fever who says to her little one, “Honey, you’re sick. I’m calling the Senator.”
Though it may not be their intent, legislators of Jim Talent’s ilk represent a reckless, albeit formidable, obstacle to medical advancement. As patients, certainly our medical autonomy, and perhaps the very quality of our available medical care, are placed at risk by medically unqualified, political interference.
That said, if you live in Missouri and want a senator who concurrently advocates and condemns therapeutic cloning, Jim Talent is your man.
- Jeff Eisen
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