Patient-matched stem cells made in South Korea

WASHINGTON -- First South Korean scientists stunned the world by cloning a human embryo. Now, using that technology and snippets of skin, they've created the first embryonic stem cells that genetically match injured or sick patients.

And they did so in ways that make it far faster and easier to grow human stem cells than many researchers thought possible.

It's a major advance in the quest to one day use stem cells to grow customized cell or tissue transplants to treat spinal cord injuries, Parkinson's and other ailments -- one likely to highlight frustration felt by many U.S. scientists.

The South Korean researchers were funded by their government. In the United States, such research wouldn't be allowed with federal funding, although some states are beginning to encourage it.

"I didn't think they would be at this stage for decades, let alone within a year," said Dr. Gerald Schatten of the University of Pittsburgh, who acted as an adviser to the Seoul lab in analyzing its data. "All of us in the biomedical communities owe our colleagues in Korea a tremendous debt of gratitude."

"This paper will be of major impact," agreed stem-cell researcher Dr. Rudolph Jaenisch of the Whitehead Institute for Biomedical Research in Cambridge, Mass. "The argument that it will not work in humans will not be tenable after this."

This is not cloning to make babies. Instead, scientists create test-tube embryos to supply stem cells -- the building blocks that give rise to every tissue in the body -- that genetically match a particular patient and thus wouldn't be rejected by the immune system.

The master cells also can come from embryos left over in fertility clinics, but those wouldn't genetically match any patient.

Any potential therapy is years away from being tested in people. But the new research marks several advances:

* Last year, the researchers from Seoul National University cloned stem cells from one healthy woman. This time, they created 11 batches of stem cells that were genetic matches to males and females, as young as 2 and as old as 56, who suffered either spinal cord injuries, diabetes or a genetic immune disease.

* Last year, it took attempts with 242 donated human eggs to grow one batch of stem cells. This time, it took an average of 17 eggs per batch, 14 if the eggs came from women younger than 30.

* The researchers eliminated use of mouse "feeder cells" that until now have been used to nourish human stem-cell lines, easing concerns about animal contamination.

"Therapeutic cloning has tremendous, tremendous healing potential, but we have to open so many doors before human trials," lead researcher Hwang Woo-suk of Seoul National University cautioned in a telephone interview. But, "our work reveals the possibility that this technology could be applied in the patient himself in the future."

More immediately, the research will allow scientists to watch the very earliest origins of diseases like Alzheimer's form inside a patient's cloned, living cells, said neuroscientist Fred Gage of the Salk Institute for Biological Studies in San Diego. That could point to new ways to prevent and treat illness, said Gage, who plans to perform some of that work.

The research also promises to fuel political sparring over whether to expand government-funded stem-cell research. Because culling stem cells destroys the days-old embryo harboring them, President Bush in 2001 banned federally funded research on all but a few old embryonic stem-cell lines. A vote on whether to ease those restrictions could come in the House as early as next week.

The Seoul researchers collected eggs donated by 18 unpaid volunteers and removed the gene-containing nucleus from them. They inserted into those eggs DNA from skin cells of patients with spinal cord injuries, diabetes or a genetic immune disease, and chemically jump-started cellular division. Thirty-one blastocysts -- early-stage embryos of 100 or so cells each -- successfully grew. From those, the scientists harvested 11 stem cell lines.

Each is a genetic match to one of the patients, and each can form other tissues, like brain cells or bone cells. Next, the scientists must learn how to control that cell development.

The work means there may be more demand for donated eggs for medical research, and women considering doing so must understand they get no benefit and face some risk from the donation process, cautioned Stanford University bioethicists David Magnus and Mildred Cho.

The advances don't mean it's time to try reproductive cloning, Hwang said. That "is unsafe and unethical," he said, noting that animal studies show more failures than successes. "Biologically, it may be impossible."