Stem cell success sparks debate
By Harold Lee
Feb. 23, 2004 9:00 p.m.
Nearly 10 years after a sheep named Dolly took her first steps,
scientists in South Korea have proven that the controversial
procedure of cloning is possible in human embryos.
Scientists from Seoul National University announced they had
cloned and harvested stem cells from 30 human embryos on Feb. 12.
In the interest of therapeutic science, 242 eggs were donated by 16
women.
Previous efforts have cloned human embryos, but the embryos did
not progress to the stage of stem cell development.
The debate of cloning for therapeutic or reproductive purposes
remains a highly charged topic in the scientific community.
“No scientist worth his or her salt would suggest cloning
a human being (for reproductive purposes),” said Fred Fox, a
professor of microbiology, immunology and molecular genetics at
UCLA.
In therapeutic cloning, embryos are cloned for the harvesting of
stem cells, and then destroyed.
Reproductive cloning, if successful, allows the genetic clone of
an organism to complete development.
The potential medical applications of harvested stem cells
““ unprogrammed cells that can change into tissue-specific
cells ““ include treatment for diseases like Parkinson’s
and juvenile diabetes.
Known as regenerative therapy, stem cells may be used to replace
damaged tissue, such as brain or pancreatic tissue, with the
regeneration of healthy tissue identical to the patient’s
own.
“You can have organs tissue-engineered that would not be
rejected by the individual,” said Edward McCabe, director of
the UCLA Center for Society, the Individual and Genetics and member
of the National Academy of Sciences.
But only embryonic stem cells have the potential to change into
all cell types, while the shape-shifting capabilities of stem cells
found in adults are limited.
These therapeutic motives differ greatly from those of
reproductive cloning.
“Until we know more about the risks, (the NAS) calls for a
ban on reproductive cloning,” McCabe said.
In 2003, the U.S. House of Representatives approved a ban on
both reproductive and therapeutic cloning. But the bill still
awaits approval from the Senate.
Federal funding for stem cell research in the United States only
extends to stem cell lines created before August 2001, and would
not extend to stem cell lines produced afterward, whether they come
from fertilized or cloned embryos.
The withdrawal of federal funds for such research in the United
States has caused scientists to relocate to places like Asia and
Great Britain, where research is less limited, Fox said.
The South Korean scientists do not intend their research to
encourage the reproductive cloning of humans.
At an American Association for the Advancement of Science
conference in Seattle on Feb. 12, Woo Suk Hwang, one of the
study’s authors, also expressed his support for an
international ban on cloning with the intent of reproduction.
Supporters for such a ban can also be found in the UCLA student
population.
“An attempt to create a human being through unnatural
means and clone a human being … is contrary to the ideas of
Bruins for Life,” said Stephen Cooke, a second-year civil
engineering student and chairman for Bruins for Life, a student
group that touts the dignity of human life.
Successful cloning, however, remains an imperfect and
painstaking process.
Yielding one successful animal clone usually takes hundreds of
unsuccessful attempts ““ as many animal clones die in
gestation or suffer from abnormalities, McCabe said.
Cloned animals tend to be larger than those conceived naturally,
so there is a concern for the surrogate mother as well as the
offspring, he said.
Though Dolly was born less than a decade ago, biotechnology
companies such as ViaGen and Cyagra are already cloning livestock
for commercial use.
In October of last year, the U.S. Food and Drug Administration
issued a report stating that meat and milk coming from cloned
livestock would be safe to eat, provided they meet the same safety
standards required for non-cloned animals.
According to Cyagra’s Web site, one cloned calf costs
$19,000. The company has already produced clones from a cow that
generated twice as much milk as the national average.
However, because of the high cost, it is unlikely that clones
themselves would be used for food and would instead be used to
produce offspring with the same desirable traits.
