Stem cell therapies involve more than simply transplanting cells into the body and waiting for them to go to work. A successful stem cell therapy requires an understanding of how stem cells work, combined with a reliable approach to ensuring that the stem cells perform the desired action in the body.

To see how therapies are developed, let's examine a real-life example: a stem cell therapy to treat Parkinson's disease in humans. This therapy made its debut in the late 1980s and was based on a successful treatment in a rat model of Parkinson's disease. Since the therapy was introduced, several research groups have been evaluating its long-term success in separate trials.

Supported by a Science Education Partnership Award (SEPA) [No. 1 R25 RR16291-01] from the National Center for Research Resources, a component of the National Institutes of Health, Department of Health and Human Services. The contents provided here are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.