NEW YORK - Scientists have finally recovered stem cells from cloned human embryos, a goal that could lead to new treatments for such illnesses as Parkinson's disease and diabetes.
A prominent expert called the work a landmark but noted that a different, simpler technique now under development may prove more useful.
Stem cells can turn into any cell of the body, so scientists are interested in using them to create tissue for treating disease. Pancreatic tissue, for example, might be used to treat diabetes.
But transplants run the risk of rejection, so more than a decade ago, researchers proposed a way around that: Create tissue from stem cells that bear the patient's own DNA, obtained with a process called therapeutic cloning.
If a patient's DNA is put into a human egg, which is then grown into an early embryo, the stem cells from that embryo would provide a virtual genetic match.
That idea was met with some ethical objections because harvesting the stem cells meant destroying human embryos.
In Wednesday's issue of the journal Cell, scientists in Oregon report harvesting stem cells from six embryos created from donated eggs. Two embryos had been given DNA from skin cells of a child with a genetic disorder, and the others had DNA from fetal skin cells.
Shoukhrat Mitalipov of the Oregon Health & Science University, who led the research, said that, based on monkey work, he believes human embryos made with the technique could not develop into cloned babies, and he has no interest in doing that.
Dr. George Daley, a stem-cell expert at Children's Hospital Boston who did not participate in the work, called the new results "one landmark step in a very long journey" toward creating DNA-matched transplant tissue.