Recently, in Nature Reviews, six leading stem cell researchers assessed the current state of stem cell technology and the challenges they face in developing clinical treatments based on the technology. The researchers shared views on the value of engineered stem cells as compared with one derived from embryos, and the potential of reprogramming normal body.
Surprisingly, one of the points they seemed to be in general agreement on was that there appears to be little difference between embryonic stem cells (ES cells) and induced pluripotent stem cells (iPS cells).
iPS cells are regular body cells that have been reprogrammed in the lab. Like embryonic stem cells, researchers have been able to get these reprogrammed iPS cells to differentiate into many cell types. For example, skin cells can be turned into nerve cells and, as one of the researchers, Dr. Konrad Hochedlinger pointed out, in fact, whole mice have been cloned starting with reprogrammed mouse iPS.
Of course, there is still a lot to learn about the about how cells differentiate and mature so it is premature to conclude that iPS cells are functionally equivalent to embryonic stem cells. However, it is surprising that these leading stem cell researcher who are most familiar with the different cells have found them to be functionally indistinguishable so far.
You can read more about this discussion in "Experts Assess the Current Status of Stem Cell Research."