In 2007, when researchers discovered a technique to reprogram adult human cells into a pluripotent state, it was hailed as one of the biggest scientific breakthroughs of the decade. These cells, called induced pluripotent stem (iPS) cells, could be used like embryonic stem cells, while avoiding the sticky ethical issues that accompany the use of cells from human embryos.
Now, researchers at Children’s have found that in at least one instance there are distinct differences between iPS cells and embryonic cells: the way they model diseases. In a study led by George Daley, MD, PhD, researchers made iPS cells from the skin cells of three patients with fragile X syndrome, the most common form of inherited mental retardation in boys. But when they compared these iPS cells with a line of cells from embryos that had been genetically diagnosed with fragile X, the cells differed in their ability to model the genetic disease.
One reason why both iPS cells and embryonic stem cells are so valuable is that researchers can study cells with a genetic mutation and watch how a disease develops in a petri dish. Much can be learned by observing a disease as it progresses, and drugs can also be tested on these cells.
This study adds more weight to the argument that the ability to make iPS cells doesn’t eliminate the need for embryonic stem cell research. “This is the first example where we can clearly show that iPS cells and embryonic stem cells behave differently in a disease model,” says Daley. “It demonstrates that embryonic stem cells remain an incredibly valuable tool for research.”