iPSCs? How do they compare?

I started doing a little bit of research on Induced Pluripotent Stem Cells (iPSCs) after they were mentioned in a radio interview I did a blog post on earlier. Some of us might remember an announcement a few years ago about a research at Kyoto University who managed to revert an adult skin cell in a mouse back to into something resembling an embryonic stem cell. This was the first iPSC. While doing my research, I found this article, which compares iPSCs to Human Embryonic Stem Cells (hESCs).

In this article the author, Dr. Maureen Condic, argues the position that iPSCs are favorable to hESCs because of ethical reasons. iPSCs don't have the same moral connotations hESCs do because iPSCs are derived from the cells of a fully formed human being, not an embryo. In this article, she also briefly discusses the problems with iPSCs, primarily the fact that it is not known if they are comparable to hESCs.

Athough Dr. Condic's arguments are fairly strong, I am somewhat troubled by her response to a question regarding whether or not "left over" embryos from fertility clinics should be used for stem cell research. For her response, she cites a somewhat vaguely worded written piece from the Clinton Administration stating that hESCs from fertility clinics are acceptable as long as no other alternatives are available. However, I disagree with this idea because for the most part, the "left over" embryos are left in cryogenic storage indefinitely or are thrown out. I've always thought this seems like a waste. Particularly in the case of being thrown out, one could argue that doing so is "destroying a baby" just as much as letting the cells be used for medical purposes that could be beneficial for others. I could see people becoming worried about people starting stem cell farms (think The Matrix, except we're not feeding robots) but not using resources that are simply byproducts from another procedure is just wasteful.

Another problem I have with Dr. Condic's arguments is the fact she holds the strong position that iPSCs are equivalent to hESCs while citing a relative lack of evidence for this. For instance, she mentions in passing that a particular researcher has authored "...one of the two iPSC studies" and mentions that it has been determined that human iPSCs are equivalent to hESCs, despite the fact that "tests for human cells are more limited." Also, the article does not mention the size of the studies, which could significantly change the outcome.Finally, Dr. Condic mentions that there have been no studies that directly correlate the performance of iPSCs with hESCs. Before I proceed, I would like to acknowledge that I am in no way trying to question the credibility of these studies, but am simply stating that I think a little more research may be in order. I also recognize the difficultly of this sort of research, but stand by my case that a little more is needed.

Finally, Dr. Condic briefly describes the risk of iPSCs becoming cancerous. This happens in iPSCs because the genes used to transform adult cells into iPSCs are inserted by a virus, which can occasionally result in accidental oncogenesis (creating genes that "turn on" cell replication). For this, she notes that researchers are working on how to fix this problem, but seems a little too optimistic about it, stating it will happen in the next year. I find this interesting because it is a problem that does not occur in hESCs (as far as I know) and therefore gives them an advantage.

I am in no way against iPSC research, I think it would be wonderful to come up with a stem cell that is free of ethical debate. However, I am still somewhat skeptical of how well iPSCs compare to hESCs. I think that research should be done on both types of stem cell until we can verify if one performs better than the other on both a biomedical and ethical scale.