The researchers then coaxed these mouse master cells into becoming blood-forming stem cells and substituted the faulty gene that causes sickle cell anemia with a working one.
FAR FROM PERFECTED
When they transplanted these cells into the diseased mice, tests showed normal blood and kidney function, they report in Friday's issue of the journal Science.
"This demonstrates that iPS cells have the same potential for therapy as embryonic stem cells, without the ethical and practical issues raised in creating embryonic stem cells," Jaenisch said in a statement.
But the technique is far from perfected.
The four genes needed to turn skin cells into master cells are delivered using a type of virus called a retrovirus.
"Once they enter the genome, there is the danger that they can silence some genes that are important or they can activate some dangerous genes that shouldn't be activated," Hanna said.
Another obstacle is that one of the four genes used is c-Myc, which is known to cause cancer.
Hanna and colleagues got around that by removing the c-Myc gene after it had done its job of converting the skin cells into iPS cells. "It is far from solving the problem," he said.
Scientists hope to use stem cells to treat a host of diseases like diabetes, Parkinson's disease and spinal injuries. And the new technique for making stem cells will make them easier to study.
But many researchers including Hanna say human embryonic stem research paved the way for such discoveries and should continue.
"They are the gold standard for what is normal and how a stem cell should behave," he said.
