January 9, 2013
A paper published in Nature today could dispel a cloud over the hopes of turning a patient’s own cells into perfectly matched replacement tissues.
Scientists first reported in 2007 that a person’s cells could be reprogrammed to an embryo-like state, and so could form any type of cell in the body. Medical researchers immediately imagined using these ‘induced pluripotent stem (iPS) cells’ to create an endless supply of genetically matched replacement tissues to treat a range of diseases: fresh pancreatic tissue for diabetics, for example, or new nerve cells for people with Parkinson’s.
The strategy also seemed to offer a way around the ethical complexities of using stem cells derived from human embryos. But then came the worries about possible side effects. Particularly bad news came from a 2011 study2 showing that iPS cells provoked immune responses when injected into the mice from which they had been derived, casting doubt over one of the key advantages of the cells.