Therapeutic cloning involves removing the nucleus from a donor egg and replacing it with a different person's nucleus in order to yield embryonic stem cells that have the capacity to develop into different types of cells which can then be used to treat disease. In a new study published in the advance online publication of Nature Medicine, researchers from Memorial Sloan-Kettering Cancer Center in New York City and the Riken Institute in Japan described their use of stem cells to treat Parkinson's disease in mice.

The investigators used skin cells from the tails of mice to derive dopamine neurons, the nerve cells that are either dysfunctional or lost in Parkinson's, a progressive brain disease that is currently incurable. They found that mice with Parkinson's disease who were treated with their own dopamine neurons demonstrated some recovery, while those who received another mouse's dopamine neurons did not improve. Due to the short duration of the study, the researchers were not able to determine if the improvements persisted over time. Still, the researchers concluded that this study demonstrated the potential for therapeutic cloning in the treatment of Parkinson's disease.

However, treatments that are successful in mice do not necessarily translate into effective human therapies. But, if the success could eventually be replicated in humans, therapeutic cloning could potentially be used to treat a host of other medical conditions.