Researchers at the Children's Hospital in Boston have figured out how to produce induced pluripotent human stem cells using skin cells. This is a considerable advance on earlier breakthroughs in which viruses were used to ferry the genes needed to transform adult cells into stem cells. As the Washington Post reports:
The new approach involves molecules known as "messenger RNA" (mRNA), which cells use to create proteins they need to carry out vital functions. Working in the laboratory, the researchers created mRNA molecules carrying the instructions for the cell's machinery to produce the four key proteins needed to reprogram into iPS cells.
After tinkering with the mRNA molecules to make signals that the cells would not destroy as dangerous invaders, the researchers found that a daily cocktail of their creations was remarkably fast and efficient at reprogramming the cells. The technique converted the cells in about half the time that previous methods did, about 17 days, and with surprising economy - up to 100 times more efficient.
"We ended up with so many colonies of cells all over the place that we had to stop the experiment," [Derrick J.] Rossi [who headed up the research] said.
Moreover, the cells had not experienced any disturbing changes in their DNA caused by previous methods and appeared much more indistinguishable from embryonic stem cells than iPS cells created using other methods. In addition, the researchers went one step further and showed that they could use the strategy to quickly and easily convert the iPS cells they created into a specific cell types - in this case muscle cells.
The really good news is that this technique produces cells that are genetically identical to the patient from whom they are derived. This would avoid the problem of immune rejection when the cells are used for regenerative therapies.
Despite this good news, the controversy over human embryonic stem cells is not yet over. According to the Post:
"With each new study it becomes more and more implausible to claim that scientists must rely on destruction of human embryos to achieve rapid progress in regenerative medicine," said Richard M. Doerflinger of the U.S. Conference of Catholic Bishops.
Rossi and other researchers, however, said that embryonic stem cells are still crucial because, among other things, they remain irreplaceable for evaluating alternatives.
"The new report provides a substantial advance," said National Institutes of Health Director Francis S. Collins. "But this research in no way reduces the importance of comparing the resulting iPS cells to human embryonic stem cells. Previous research has shown that iPS cells retain some memory of their tissue of origin, which may have important implications for their use in therapeutics. To explore these important potential differences, iPS research must continue to be conducted side by side with human embryonic cell research."
Still, if such IPS cells prove out, one can see the end of using stem cells derived from embryos. It is time for supporters of human embryonic stem cell research like me to acknowledge that opposition probably pushed these breakthroughs along. On the other hand, it is also time for opponents of human embryonic stem cell research to acknowledge that these breakthroughs would most likely have been impossible without earlier work on human embryonic stem cells.
In any case, both sides can be happy today with these results.