Tuesday, May 24, 2005

South Koreans Report Major Development in Stem-Cell Research

South Korean scientists reported Thursday that they've generated the first human embryonic stem-cell lines carrying genes that match the DNA of patients suffering from disease or spinal-cord injury.

The development, described in a paper published online Thursday by the journal Science, represents a major step in the field of stem-cell research. The immediate impact is that researchers could soon study cells carrying specific variations of disease in the laboratory.

Eventually, scientists hope that the same technology will allow the generation of healthy cells that can be transplanted into patients to replace cells damaged by disease or injury.

"What the study shows is that stem cells can be made that are specific to patients regardless of age or sex, and that these cells are identical genetic matches to the donor," said Dr. Gerald Schatten, vice chairman of research development in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh. He helped the Korean team analyze and prepare an English-language manuscript of the findings.

"If they can be safely used in transplant, the promise for effective treatment _ perhaps even cure _ of devastating diseases and injuries comes within reach," Schatten said.

The same researchers reported last year that they had successfully cloned a human embryo to produce an embryonic stem-cell line, setting off a new round of calls for international controls or bans on cloning, although the scientists say they have no intention of cloning to produce a baby, stressing that all evidence indicates that the cells would result in serious abnormalities.

The embryos they used were allowed to develop for only six days, long enough to derive the stem cells that are thought to be able to differentiate to form any type of cell found in the body.

News of their latest accomplishment comes as Congress considers relaxing federal limits on government funding to support embryonic stem-cell research, a move strongly opposed by many groups on moral and religious grounds because fertilized eggs are destroyed in the process.

The team, led by Woo Suk Hwang, a veterinary professor at Seoul National University, collected eggs from 18 unpaid volunteers and removed the nucleus containing genetic material from each of them. Then they inserted DNA derived from skin cells of 11 patients, nine of them suffering from spinal-cord injury, and one each with type 1 diabetes or a congenital immune disease.

The researchers were able to grow 31 early-stage embryos from this process, and from those, harvested 11 different stem-cell lines, each a genetic match to one of the skin-cell donors.

While the researchers in their first cloning experiment had to use 242 donated eggs to produce just one stem-cell batch, in the new effort, an average of 17 eggs were required for each line of stem cells.

The patients donating skin cells ranged in age from 10 to 56, and their age or gender did not seem to make a difference in the ease of producing stem cells. However, the researchers found they had more success with eggs donated by women younger than 30. Most stem-cell lines, including those approved for research in the United States, have not been developed through such direct donations, but from eggs harvested from women who were undergoing fertility treatment and then donated them for research.

The researchers are now doing more testing on the stem-cell lines to determine whether they could be tolerated by patients' immune systems and if they could be guided to develop into the kind of cells needed to treat injury or illness.

They are testing some of the lines in animals with spinal-cord injuries, but Hwang said they are some years away from considering doing any transplants into people. "We have to be overconvinced" that the cells are safe, he said.

Breakout material

South Korean researchers report they've used cloning techniques to create the first human embryonic stem-cell lines specifically tailored to match the genes of people suffering from injury or illness.

"What the study shows is that stem cells can be made that are specific to patients regardless of age or sex, and that these cells are identical genetic matches to the donor." _ Dr. Gerald Schatten, a researcher at the University of Pittsburgh.

By: LEE BOWMAN (Scripps Howard News Service)