BioEd Online

South Korean stem-cell scientists have once again stunned the world with a major breakthrough: they have made cell lines that are tailored to individual patients.

The team, led by Woo Suk Hwang of the Seoul National University, is used to the spotlight. Last year, it made the first stem-cell line from cloned human cells, drawing the world's attention. A stem-cell line can produce cells indefinitely in the lab, allowing scientists to study them in detail.

Now, the team has taken its work a significant step further by making stem-cell lines from several patients with different diseases. Scientists hope that by studying these lines, they will be able to watch how diseases unfold, and learn how they might be cured.

"This is spectacular work," says George Daley, a stem-cell researcher at Harvard Medical School in Boston, Massachusetts, who was not involved with Hwang's efforts. "It just moves the field forward so quickly. It really convinces you that this is practical and feasible."

The team says it has produced 11 human embryonic stem-cell lines from 11 cell donors. The donors included men, women and children, some with diseases such as diabetes or injuries to the spinal cord. The scientists report their work online in Science¹.

Individual lines

Each cell line has exactly the same genetic sequence as its donor's own cells. As stem cells, they can be prompted to grow into any type of human cell, so they could reveal clues about how each patient's illness developed.

For instance, by allowing the stem cells to develop into the cells that produce insulin, scientists might discover the signals that trigger their destruction in diabetics. Such patient-specific stem-cell lines have never been created through cloning before.

"Figuratively, you can move a patient's disease into the Petri dish and study it using human embryonic stem cells," says Daley.

Scientists may one day be able to modify the cells and put them back into individuals to cure their conditions. But such therapies are still many years away.

Efficient eggs

Hwang's paper has also improved on the cloning procedure he reported last year². To make a cell line, scientists take a sample of skin cells from a donor. They then suck out the nucleus of each skin cell, and implant it in a human egg whose own nucleus has been removed.

The eggs grow into a structure called a blastocyst, a round ball of cells that forms early in human development. Scientists remove the stem cells from this blastocyst and transfer them to a support scaffold, where they grow until researchers are ready to experiment on them.

In Hwang's previous research, his team harvested 242 eggs from 16 different women to house the nuclei from the donor skin cells. After collecting all those eggs, the team was able to make only one stem-cell line. But in the research released today, the team says it used an average of 17 eggs to make each line, a major improvement in efficiency. This is important because the procedures that stimulate women to produce eggs, and the techniques for removing them, carry health risks and can cause discomfort.

Gerald Schatten, a biologist at the University of Pittsburgh School of Medicine in Philadelphia who worked with the Korean team, says such improvements are crucial if stem-cell research is to live up to its potential. "This accelerates the research, makes it more relevant and might even make it less expensive," he says.