Canadian and British stem cell researchers are reporting an exciting new method for producing stem cells from adult cells without using viruses. In 2006, researchers in Japan and Wisconsin discovered how to use viruses to ferry four genes that turn adult cells into stem cells that act very much like embryonic stem cells.
Like stem cells derived from embryos, the induced pluripotent stem (iPS) cells can differentiate into various cell types that could be used as transplants to replace diseased or damaged tissues. In addition, since the stem cells are produced using adult cells taken from individual patients, they would be genetic matches for each patient. This would mean that transplants of such cells would not risk being rejected by a patient's immune system.
However, researchers worried that using viruses to produce iPS cells might result in cancer. The new technique uses the piggyBac transposon derived from butterflies to incorporate into skin cells the suite of four genes necessary to transform them into stem cells. (A transposon ia a mobile DNA sequence that can move from one site in a chromosome to another, or between different chromosomes.) Once the genes are installed, the transposon can be completely eliminated from the cells. If iPS cells work out, another tremendous advantage to them is that they can be produced without using scarce human eggs.
In addition, opponents of human embryonic stem cell research argue that the new iPS cells are not morally problematic (from their point of view) because they are not derived from human embryos. On the other hand, it might be that iPS cells produced from skin cells could become embryos capable of developing into babies if implanted in a womb. The possibility that a soul can enter a specific cell evidently may depend on whether or not a single genetic switch is on or off.
In any case, the new research is a very promising avenue to the development of regenerative medicine.