Stem cells recovered from cloned human embryos

NEW YORK Scientists have finally recovered stem cells from cloned human embryos, a longstanding goal that could lead to new treatments for such illnesses as Parkinsons disease and diabetes.

A prominent expert called the work a landmark but noted that a different, simpler technique 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. Transplanting brain tissue might treat Parkinsons disorder, for example, and pancreatic tissue might be used for 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 patients own DNA, obtained with a process called therapeutic cloning.

If DNA from a patient 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. So in theory, tissues created from them would not be rejected by the patient.

That idea was met with some ethical objections because harvesting the stem cells involved destroying human embryos.

Scientists have tried to get stem cells from cloned human embryos for about a decade, but theyve failed. Generally, thats because the embryos stopped developing before producing the cells.

In 2004, a South Korean scientist claimed to have gotten stem cells from cloned human embryos, but that turned out to be a fraud.

In Wednesdays edition of the journal Cell, however, scientists in Oregon report harvesting stem cells from six embryos created from donated eggs. Two embryos received 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 the success came not from a single technical innovation, but from revising a series of steps in the process. He noted it had taken six years to reach the goal after doing it with monkey embryos.

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Stem cells recovered from cloned human embryos