Update: Stem cell benefits getting closer
Scientists are transforming stem cell science into stem cell medicine.
Many diseases involve the death of specialized cells that the body cannot naturally replace. A heart attack suddenly kills heart muscle cells. A stroke suddenly kills—and Alzheimer's disease slowly kills—brain cells. A perfect treatment would replace these lost cells, with cells exactly like them, but the body cannot do that on its own.
The discovery of stem cells offered an alternative, says Dr. David Scadden, co-director of Harvard's Stem Cell Institute. "We already have an example of successful adult stem cell therapy—a blood stem cell transplant (sometimes called a bone marrow transplant)."