Two publications (Science and Cell) published papers today showing that scientists have succeeded in reprogramming human adult cells to behave much like human embryonic stem cells (hESCs). Following on findings published several months using mouse rather than human cells, the researchers responsible for today’s results were able to spur the reprogramming by inserting four genes into the adult cells.
The big question is whether this new technique will quell the stem cell research controversy, which arises largely from the fact that the stem cells scientists believe have the greatest medical potential are today derived from 5-day old embryos. The answer is “maybe.” Scientists interviewed in today’s New York Times article were ebullient about the results, but it is worth remembering that there have been two major scientific discoveries in the last 18 months that promised to end the debate and then quickly faded from public view. In the summer of 2006, scientist Robert Lanza showed that it was possible to produce hESC lines without destroying embryos by carefully removing single cells from many 8-cell embryos. Although long term effects are unknown, we know that removing a single cell from an embryo at that stage does not prevent it from developing. This technique is routinely used to obtain genetic material for preimplantation genetic testing, and the embryos (less one cell) are successfully used for implantation by in vitro fertility clinics. In January of this year, scientists from Harvard and Wake Forest Universities reported that they had discovered stem cells in amniotic fluid that possessed many traits of hESCs.
I am optimistic about today’s discovery, but three questions remained to be answered, two scientific and one philosophical.
The scientific questions: First, will further research show that these reprogrammed cells actually have all the features of hESCs that make the latter [...]