A South Korean team of researchers has for the first time created a number of new human stem-cell lines that carry the genetic signatures of diseased or injured patients, according to a report to be released today in the US magazine, Science.
The development at the Seoul National University signified a dramatic leap in speed and efficiency of stem-cell production, and "moves scientists one step closer to the goal of transplanting healthy cells into humans to replace cells damaged by diseases such as Parkinson's and diabetes," said the American Association for the Advancement of Science, which publishes Science.
The work of the Korean scientists "will make waves in laboratories and legislatures around the world," the magazine editors wrote.
Veterinarian Woo Suk Hwang and gynecologist Shin Yong Moon, who led breakthrough research last year and were part of the current study's 24-member team, emphasized that the 11 stem-cell lines they produced are not yet fit to be transplanted into the patients. They cited scientific and ethical reasons for such inhibitions.
"We have to be over-convinced" that the cells are safe, Hwang said.
They also emphasized that their work did not provide "any encouragement for dangerous human reproductive cloning attempts."
Rather, the stem-cell lines being produced in the Seoul research lab will likely be used to study disease progression and "assist in drug development," Hwang wrote.
Last year, Hwang and Moon produced one cell line from more than 200 attempts. But in this project, they produced one cell line for every 20 tries, for a ten-fold jump in efficiency.
One of their new techniques involved making a small tear in the donor egg, squeezing out the donor chromosomes, then inserting a skin cell from the patient through the tear and applying an electric shock to fuse the two cells, the magazine said.
Previous less-successful techniques used a needle to suck out the egg's nucleus, and applied antibodies to kill the outer egg-cell layer.
"It's a breakthrough that I didn't think would happen for decades," said developmental biologist Gerald Schatten, of the University of Pittsburgh, an advisor to the Korean team.
Stem cell research has been controversial because it involves harvesting young cells from embryos or umbilical cords that have the capability of being transformed into muscle, intestinal, bone and other tissues.
The Korean researchers took skin cells from 11 male and female patients ranging in age from 2 to 56. Nine of the patients suffered spinal-cord injuries. Another patient suffered from congenital genetic disease "hypogamma-globulinemia," and the final patient suffered juvenile diabetes. The skin cells were implanted into eggs from female donors who were not biologically related to the patients, from which embryos were grown and harvested after about six days.
"In all 11 cases, the genetic fingerprint of each line matched that of the skin-cell donor," Science wrote.
The patient-specific stem cells could eventually provide therapeutic cells that have "immunological compatibility" with the patient, which is important to overcome the tendency for the body to reject implants from other humans.
The South Korean team said another reason the stem-cell lines could not be used for treatment is that they are "still likely to be defective." One major hurdle is to eliminate the "remaining animal components" such as animal serum and enzymes from the production process.
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