Mar 3, 2003
UPI Medical Correspondent
A key congressman in the debate on Capitol Hill over human cloning has repeatedly insisted there are no studies showing the potential for therapeutic cloning to treat disease, but numerous scientific experts in the field told United Press International such a statement is not true and several well-known and major studies suggest the technique could be useful to treat a wide range of diseases.
Rep. Dave Weldon, R-Fla., author of H.R. 534, the Human Cloning Prohibition Act, which was passed by the House of Representatives last week, said on the House floor before the vote, "The fact of the matter is, the evidence isn't there" to support the medical potential of therapeutic cloning.
Weldon, who was a physician for 15 years and whose opinion on biotechnology is often given a lot of weight on Capitol Hill, insisted there was not a single study -- not even in animals -- indicating the technology could be used to treat disease.
Scientists said that is far from the truth and cited numerous studies showing that therapeutic cloning already has been used in animal studies to treat such ailments as multiple sclerosis, paralysis, Parkinson's disease.
Weldon's "statement is embarrassing particularly coming from somebody who supposedly has a medical degree," said Dr. Robert Lanza, vice president of medical and scientific development at Advanced Cell Technology of Worcester, Mass., which is developing treatments based on therapeutic cloning.
"There are a number of papers that very clearly show the powerful therapeutic value of therapeutic cloning," Lanza said. "All of these studies have gotten massive publicity so it's not like (Weldon)'s unaware of them. He is trying to perpetuate misinformation and he knows better."
Most U.S. genetic scientists and members of Congress favor a ban on the use of cloning for the purposes of human reproduction. The debate centers around whether therapeutic or research cloning should be allowed.
Therapeutic cloning involves transferring the nucleus or DNA material from a patient's cell into a donor egg cell. Under the right conditions, this creates an embryo and embryonic stem cells that have the potential to become any cell in the body and thus replace cells or tissues damaged by disease.
Scientists think therapeutic cloning has the potential to lead to treatments for disease but it poses a moral dilemma for some senators and congressmen who oppose the technology because it requires the destruction of the embryo to obtain the stem cells.
Larry Goldstein, a stem cell researcher at the University of California, San Diego, agreed with Lanza about the potential of the technology.
"There are plenty of proof of principle experiments on animals with disease models," said Goldstein, who has testified before Congress on stem cells. "They're out there and they're not hard to find," he said, noting the studies have appeared in reputable journals such as Nature and Science.
"Stack up Congressman Weldon's statements about the science and compare them to the statements of those who see great opportunities here," which include 40 Nobel laureates and the National Academy of Sciences, Goldstein said. "Why would we value (Weldon's) opinion about this ... rather than these (scientists)."
Weldon's spokesman, who declined to be named in this article, maintained the studies cited do not show therapeutic cloning has the potential to treat disease.
In some cases, the spokesman argued, researchers might have performed additional steps after deriving specific tissue cells from embryonic stem cells and in other cases they might not have been using stem cells obtained via therapeutic cloning. To Weldon, such possibilities nullify the validity of the studies because they have not proven therapeutic cloning could treat disease.
"You'd be naïve to think there is no medical potential with this technology," Lanza said, citing papers in peer-reviewed science journals such as Science, Nature Medicine and the Journal of Clinical Investigation showing the promise of therapeutic cloning. "You'd have to have your head in the sand."
Lanza's own group published research last July in Nature Biotechnology showing therapeutic cloning could be used to generate functioning kidneys.
Paul Berg, a Nobel laureate and director of the Beckman Center for Molecular and Genetic Medicine at Stanford University, called Weldon's statements "asinine" and "a Luddite kind of view."
Berg cited three studies showing the potential of therapeutic cloning of cells to treat disease. In one done by researchers at the National Institutes of Health, brain cells derived from embryonic stem cells were transplanted into the brains of mice with a genetic defect that simulates Parkinson's disease. The symptoms were alleviated and the cells seemed to function as normal brain cells, Berg said.
In another experiment done at the Christopher Reeve Center at the University of California, Irvine, neuron cells derived from embryonic stem cells were injected into a paralyzed rat. The rat regained the ability to walk, suggesting the cells are "capable of restoring function where you have spinal cord damage," Berg said.
The third study showed promising results for treating diabetes. A group of researchers at Stanford showed insulin-producing cells could be implanted into diabetic mice, enabling them to make insulin and maintain nearly normal blood sugar levels, Berg said.
Weldon's bill includes a provision that bans importation of any therapies derived from this procedure. That action puzzles Berg, he said, because if the technology has no potential -- as Weldon contends -- there is no need to prohibit therapies that might result from it.
"Not only does it not make any sense to me, it outages me," Berg said. "It is the ultimate in arrogance because ... Weldon and (his Senate counterparts) have decided this technology offends them and therefore the 280 million who could benefit from this ... should not have access to it."
Weldon's spokesman said the importation ban was put in the bill to reduce the likelihood people would use the technology for reproductive cloning. But the spokesman noted Weldon previously has said if medically useful therapies are developed from cloning, "The U.S. Congress would revisit the bill."
The Senate has not yet voted on cloning this
session but it deadlocked on the issue last year. In addition to the anti-cloning
bill introduced by Sen. Sam Brownback, R.-Kan., bipartisan legislation
that would ban reproductive cloning but allow therapeutic cloning also
has been introduced in the Senate.
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