Cell reprogramming: expectations and challenges for chemistry in stem cell biology and regenerative medicine.

The possibility of reprogramming adult somatic cells into pluripotent stem cells (iPSCs) has generated a renewed interest into stem cell research and promises to overcome several key issues, including the ethical concerns of using human embryonic stem cells and the difficulty of obtaining large numbers of adult stem cells (Belmonte et al., Nat Rev Genet, 2009). This approach is also not free from challenges like the mechanism of the reprogramming process, which has yet to be elucidated, and the warranties for safety of generated pluripotent cells, especially in view of their possible therapeutic use. Very recently, several new reprogramming methods have surfaced, which seem to be more appropriate than genetic reprogramming. Particularly, chemically induced pluripotent cells (CiPSs), obtained with recombinant proteins or small synthetic molecules, may represent a valid approach, simpler and possibly safer than the other ones.