In 2001, President George W. Bush issued an executive order banning federal funding for new sources of stem cells developed from preimplantation human embryos. The action stalled research and discouraged scientists.
Five years later, a Kyoto University scientist, Shinya Yamanaka, and his graduate student, Kazutoshi Takahashi, re-energized the field by devising a technique to “reprogram” any adult cell, such as a skin cell, and coax it back to its earliest “pluripotent” stage. From there it can become any type of cell, from a heart muscle cell to a neuron.
The breakthrough sidestepped the embryo controversy, offering researchers an unlimited supply of stem cells. Dr. Yamanaka shared the 2012 Nobel Prize in Physiology or Medicine for reprogramming mature cells into what are now called induced pluripotent stem cells, or iPS cells. Still, the march toward new treatments has been halting.
