WASHINGTON — Scientists reported Thursday they had developed a technique that can quickly create safe alternatives to human embryonic stem cells, a major advance toward developing a less controversial approach for treatment of a host of medical problems.
The researchers published a series of experiments showing they can use laboratory-made versions of naturally occurring biological signals to quickly convert ordinary skin cells into cells that appear virtually identical to embryonic stem cells. Moreover, the same strategy can then coax those cells to morph into specific tissue that would be a perfect match for transplantation into patients.
The work was praised as a breakthrough.
"This paper is a major paper, in my view, in the field of regenerative medicine," said Douglas Melton, who co-directs the Harvard Stem Cell Institute.
Opponents, meanwhile, seized on the advance as the most convincing evidence yet that alternatives were sufficient, rendering the morally questionable cells unnecessary.
Rossi and other researchers, though, said embryonic stem cell research was still crucial because, among other things, embryonic stem cells are irreplaceable for validating alternatives.
Nevertheless, the announcement, described in a paper published in the journal Cell Stem Cell, could mark a pivotal moment in the long, contentious history of embryonic stem cell research.
The advance comes as the future of federal funding for embryonic stem cell research hangs in doubt. A federal judge stunned the field Aug. 23 by ruling that the Obama administration's new more permissive policy for funding the research violated a federal law barring taxpayer dollars from being used for studies that involve destroying human embryos.
The National Institutes of Health said that it supports research only on cells that have been obtained by privately funded scientists. An appeals court Tuesday let the NIH continue the funding as the case winds through the legal system.
Scientists hope embryonic stem cells will lead to cures for diabetes, Alzheimer's disease, Parkinson's disease, spinal cord injuries and a host of other ailments because they can turn into almost any tissue in the body. But they can be obtained only by destroying days-old embryos, which some consider equivalent to killing human life.
The new stem cell approach involves molecules known as "messenger RNA," or mRNA, which the DNA inside cells uses to create proteins they need carry out various vital functions. The researchers created mRNA molecules carrying the instructions for the cell's machinery to produce the four key proteins needed to reprogram themselves into pluripotent stem cells (iPS cells).
After tinkering with the mRNA molecules in the laboratory to make signals that the cells would not destroy as dangerous invaders, the researchers found that a daily cocktail of their creations was surprisingly fast and efficient at reprogramming the cells. The approach converted the cells in about half the time of previous methods — only about 17 days — with surprising economy — up to 100 times more efficient than the standard approach.
Moreover, detailed tests indicated the cells had not experienced any disturbing changes in their DNA caused by previous methods and were virtually identical to embryonic stem cells.