Ever since the process was discovered, pro-lifers have held up induced pluripotent stem cells – adult cells that have been reprogrammed back to an embryonic-like (pluripotent) state – as a great ethical alternative to creating, using and destroying human embryos to obtain embryonic stem cells. Even some ESCR proponents have abandoned their previous work with ESCs to work exclusively with iPSCs and a few years ago, Oprah’s Dr. Oz declared on her show that “The stem cell debate is dead” now because of this discovery. Like everyone else, I, too, am delighted that scientists have discovered a way to reduce the perceived “need” to tear apart tiny human beings in the name of science, however, I’ve remained very cautiously optimistic about the promise of this research, mostly because, if true ESCs are plagued with problems like tumor formation and tissue rejection, wouldn’t embryonic-like stem cells have similar problems?

Turns out my suspicions are not without merit. The NY Times reported last week that in a recent study in mice iPS cells made from skin cells were rejected by the recipients, even though they were derived from the patients’ own cells.

“The path to the clinic has just gotten a lot murkier,” said Dr. Robert Lanza, chief scientific officer of Advanced Cell Technology, a company trying to develop medical treatments using both embryonic stem cells and induced pluripotent stem cells.

He said it was not clear that the results in mice would hold true for humans, though some other scientists said they assumed they would.

The new report is just the latest to take some of the shine off iPS cells. In recent months other researchers have reported that the cells are prone to various types of genetic abnormalities.

Now, as long as it’s ethical I have no objection to this research being done despite discouraging results such as this, it is still in its infancy, after all (and Rebecca Taylor points out that there is also some iPS cell good news), but I still say adult stem cells are the way to go. As Dr. Prentice points out today, ASCs are treating thousands of patients – now – and advancements are being made everyday – from discovering new sources of pluripotent cells to growing human organs in the lab.

Other smarties commenting:
Rebecca Taylor
Wesley Smith