Modern Day Alchemy: Making Blood from Skin
This finding is exciting for several reasons. Although previous investigators had figured out how to cause an adult skin cell to re-differentiate into embryonic stem cells – so-called induced pluripotent stem cells (IPS cells – see Oct 1st blog) – there are technical and safety issues related to the ultimate use of these cells as a human therapeutic. To be therapeutically useful, these cells must next be guided to form the desired tissue type, for example, blood cells. While this is possible, it is not a very efficient process; many of the IPS cells are lost along the way. The safety issue has to do with the induced pluripotency itself – these cells have the ability to self-renew indefinitely, and there are some concerns that this trait may be too reminiscent of cancer cells for comfort. Bypassing the induced pluripotency and going straight to the blood cells means that both of these issues can be avoided.
When these blood cell precursors were transplanted into mice, they functioned as normal blood cells. And although so far the only human cell type that has seen this kind of direct conversion is skin to blood cells, previous groups have demonstrated the transformation of adult mouse skin cells directly into functioning mouse heart cells and mouse neurons. So although all of these findings are many steps and many years away from even being tested in human clinical trials, they do offer the tantalizing possibility that one day a patient in need of a blood transfusion or replacement for damaged heart tissue may have to look no farther than his own skin.