Human Embryo Stem Cells (hESC) are capable of generating all types of human body cells but they are obtained by destroying human embryos. In 2006, Professor Yamanaka developed a technique for reprogramming adult cells into pluripotent stem cells. These “iPS” cells appear to have the same capacities as hESCs but do not pose ethical problems. However, iPS cells have met with opposition from embryo researchers claiming that iPS cells are not exactly equivalent. The scientists mainly base their argument on certain gene activity which does not seem identical in hESC and iPS cells.
It is important to establish whether hESC and iPS cells are similar “because clinical trials are currently underway with both types of cell”, and the ethical stakes are high.
The study carried out by Hochedlinger and his team, which was published in the Nature Journal on 26 October, reaches the following conclusion: “Based on our trials, it seems impossible to distinguish between the two types of cell in terms of function”. On the one hand, scientists have shown that iPS cells have the same capacity to differentiate themselves into all types of cell and, on the other hand, that the differences observed in terms of gene activity are due to epigenetic variations, not cells.