Researchers customize stem-cell lines

May 19, 2005 - Researchers in South Korea say they have created the first human embryonic stem-cell lines using DNA from injured or sick donors who could theoretically benefit from such cells.

The new cloning experiment, detailed in a paper published Thursday on the journal Science's Web site, builds on groundbreaking research that was published last year by the same group.

"This report brings science a giant step forward toward the day when some of humankind's most devastating diseases and injuries can be effectively treated through the use of embryonic stem cells," said the research team's leader, Woo Suk Hwang of Seoul National University.

However, the experiment also raises fresh ethical and regulatory questions about embryonic stem-cell research, just as Congress is preparing to take up the subject.

What stem cells do
Throughout the life of an organism, stem cells replenish the tissues that make up the body, ranging from bones and blood to brain cells. Embryonic stem cells show the most versatility, and scientists hope that such cells can someday be harnessed to repair severed spinal cords, heal damaged hearts, boost brain cells in Parkinson's disease patients and work other medical wonders.

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An essential part of the dream is being able to tailor stem cells to reflect the genetic makeup of the patients themselves. Otherwise the new tissue might face rejection by the body into which it is transplanted. The new research represents a significant step in that direction — and also improves dramatically on the production process that has been pioneered by the Korean group.

Embryonic stem cells are extracted during the blastocyst stage — when the embryo is about the size of a grain of sand, comprising 100 to 200 cells in all. Typically, researchers take the stem cells from embryos that are left over from test-tube fertilization procedures, destroying the embryo in the process.

Hwang and his colleagues do not use surplus test-tube embryos to create their stem-cell lines. Instead, they employ a cloning technique known as somatic-cell nuclear transfer. In this process, the nucleus from an unfertilized donor egg cell is replaced with nuclear material from a different kind of cell. Then the egg is processed with electricity and chemicals, coaxing it to grow to the blastocyst stage.

Last year, the Korean group announced a single success: the creation of one stem-cell line after 242 tries. In that case, the same woman donated the egg as well as surrounding cells, known as cumulus cells, which were the source of the inserted nuclear material.

For the newly reported research, 18 women donated 185 eggs. Meanwhile, 11 donors, ranging in age from 2 to 56, donated abdominal skin biopsies that were cultured to provide the nuclear material for injection into the eggs. Nine of the skin donors had suffered spinal-cord injuries; one had juvenile diabetes; and one had congenital hypogamma-globulinemia, a type of immune-deficiency disease.

FREE VIDEO Stem cell advance May 19: Scientists use a cloning technique to create tailored stem cells. NBC's Robert Bazell reports. Nightly News

In 10 cases, the egg donors were not biologically related to the skin donors, while in the 11th case, a woman donated the egg as well as the skin. Eleven new stem-cell lines were created, based on genetic material from nine of the skin donors.

"A year ago, the world was stunned when Professor Hwang announced that out of 242 eggs, they were able to establish one stem-cell line. Now the great news is that 16 times fewer women would be called upon to donate for this type of research," said Gerald Schatten, a co-author of the Science study and director of the Pittsburgh Development Center at the Magee-Womens Research Institute.

What's more, lab-culture tests indicated that the stem cells would be immunologically compatible with the skin donors. If the process could be perfected, the healthy cells could be transplanted safely into the spinal-cord patients. But that's a big "if."

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