The study is one of more than 100 clinical trials exploring the potential of stem cells to replace or supplement tissues in debilitating or life-threatening diseases, including cancer, diabetes, epilepsy, heart failure and some eye diseases.
Researchers expect some stem-cell therapies to enter the clinic soon. Treatments for some conditions, they say, could become part of general medicine in five to ten years.
During development, pluripotent ES cells, which have the potential to become many cell types, turn into the specialized cells of the brain, heart, lungs and so on.