THURSDAY, May 19, 2005 (HealthDay News) -- In a scientific triumph as notable for its ethical implications as its novelty, researchers in South Korea have used DNA from people suffering from injury or disease to create 11 embryonic stem cell lines that can now be used to study human frailties in the laboratory.
What may be most unusual about the feat is the fact that the scientists did it using human eggs with the nucleus removed, instead of fertilized embryos. Experts note this new method might sidestep the ethical controversy that has surrounded such research from its start.
"This brings us a giant step forward toward the day when humankind's most devastating diseases and injuries can be cured through the use of stem cells," said study author Dr. Woo-Suk Hwang, a professor at Seoul National University in South Korea.
Hwang spoke at a news conference held in London to announce the accomplishment, the details of which are published in the May 19 issue of Science.
"The only way to study the disease state is by starting with the disease state. Right now, it is possible to derive patient-specific stem cells in which we could understand the root causes of a variety of diseases," added study co-author Gerald Schatten, vice chairman of research development in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh's School of Medicine.
"This is important in our country because only a limited percentage of our population participate in infertility treatments," he added.
"If stem cells are only derived from leftover embryos from IVF, I'm very fearful that full diversity of our nation would not be represented in those lines," he continued. "With this technique, it is straightforward to get skin scrapings from a variety of patients from all different populations around the world and be able to generate lines that would represent the full diversity both of disease and of our human population."
Schatten's statements illustrate one apparent advantage of the breakthrough: to be able to avoid the ethical concerns accompanying the use of stem cells derived from human embryos, which are destroyed in the process. The issue is a political hot pepper in the United States, with House Majority Leader Tom DeLay (R-Texas) just announcing that he would oppose a measure to expand federal financing of stem cell research.
"There's no path of fertilization in our process," Hwang stated unequivocally. "This result is not an embryo, just a nuclear transfer construct."
But even if the research may sidestep some issues, it raises many others, including the specter of human cloning. Again, the authors of the study dismissed this possibility.
"Reproductive cloning is not our goal," Hwang said. "It is unsafe and unethical, so it shouldn't be done in any country. And also, biologically, it may be impossible."
Last year, Hwang and his colleagues made headlines when they announced the first successful cloning of human embryonic stem cells. Unlike the latest research, those lines used genetic material and eggs from the same woman.
For the current research. Hwang and his colleagues used 185 eggs donated specifically for research purposes by 18 women, as well as skin cells from 11 donors who had various conditions including spinal cord injury, juvenile diabetes or a genetic immune condition called congenital hypogammaglobulinemia. Nine of the 11 lines that were eventually produced came from the spinal cord injury patients.
The researchers then conducted a nuclear transfer, meaning they took a nucleus (containing the person's DNA or genetic information) from a skin cell and moved it into an egg, which had already had its nucleus removed.
The eggs were then allowed to develop into the blastocyst stage of embryonic development. Stem cells were derived from the inner cell mass of the blastocyst.
One major advantage to this process is that 16-times fewer women would be needed to donate.
"We have every reason to think that disease-carrying stem cells can be generated at high efficiency," Schatten said. "Furthermore, the initial immunological testing shows that these lines appear to be immune matches to the person who donated the skin cells."
This last point means that possible rejection of transplanted tissues might be avoided in the future.
Experts were careful to emphasize that cures are not around the corner and the main benefits, at least for now, are likely to be seen only in the lab.
"It could change research," acknowledged Dr. Darwin Prockop, director of the Center for Gene Therapy at Tulane University Health Sciences Center in New Orleans. "It could be a way of doing basic research which might come up with a new therapy which wouldn't be related to stem cells."
But even the research road is fraught with problems.
The authors of an accompanying paper in the journal highlighted several areas of ethical concern raised by this research.
One had to do with ambiguities surrounding the egg donors. "These people are not really research subjects in the traditional sense, nor are they patients," said David Magnus, co-author of the paper and director of the Stanford Center for Biomedical Ethics. "We need a new way of framing of how we think about research participants." Magnus suggested a new category called "research donors."
Magnus also objected to the phrase "therapeutic cloning," which could mislead research participants into thinking actual therapies are on the horizon.
"It's important that they not be misled about how close we are to therapy, and that research is not therapy," Magnus said. "We think language such as 'therapeutic cloning' is misleading. We recommend other language, such as 'embryonic stem cell research'."
But within the maze of issues raised by this achievement, even ethicists seemed inclined to agree that this represents a more realistic way of producing stem cell lines.
"There's no reason to believe that any of these things could ever become a human being, even if someone wanted to, given where we are in science," Magnus said. "These are not people. That's one of the reasons why, in some ways, from an ethical point of view, somatic cell nuclear transfer is a better way of producing stem cells than use of IVF."
More information
To learn more about stem cells and stem cell research, head to the International Society for Stem Cell Research.
