A number of past studies have shown improvement in Parkinson's disease with stem cell transplants. Here is another: "Endometrial stem cells injected into the brains of mice with a laboratory-induced form of Parkinson's disease appeared to take over the functioning of brain cells eradicated by the disease. The finding raises the possibility that women with Parkinson's disease could serve as their own stem cell donors. Similarly, because endometrial stem cells are readily available and easy to collect, banks of endometrial stem cells could be stored for men and women with Parkinson's disease. ... In the current study, the researchers generated stem cells using endometrial tissue obtained from nine women who did not have Parkinson's disease and verified that, in laboratory cultures, the unspecialized endometrial stem cells could be transformed into dopamine-producing nerve cells like those in the brain. The researchers also demonstrated that, when injected directly into the brains of mice with a Parkinson's-like condition, endometrial stem cells would develop into dopamine-producing cells. ... stem cells derived from endometrial tissue appear to be less likely to be rejected than are stem cells from other sources."