Researchers report that grafted neural stem cells may partially reverse the symptoms of Parkinson’s disease in rats via the direct release of dopamine into a part of the forebrain known as the striatum. Loss of dopaminergic neurons and a corresponding decline in dopamine release are hallmark signs of Parkinson’s disease. Previous studies have explored the use of cell-replacement therapy using dopamine-like neurons generated from self-renewable primitive neural stem cells. But it remains unclear whether this strategy can fully restore dopamine levels in the striatum, and whether the dopamine is released by the transplanted neurons or by the surrounding healthy cells in the striatum. 

Zhuan Zhou's lab demonstrated that grafted neural stem cells directly release dopamine in the damaged striatum in vivo and partially rescue a rat model of Parkinson’s disease.  The authors combined two existing methods—microdialysis-based high-performance liquid chromatography (HPLC) and nafion-coated carbon fiber electrodes (CFE)—to identify the released substance as dopamine and locate the site of its release in the rat striatum. The findings revealed that dopamine release and reuptake by the grafted neurons reduced abnormalities related to the progression of Parkinson’s disease and alleviated symptoms of the disease in rats. According to the authors, the findings provide proof-of-concept evidence to potentially support future clinical translation.

Xinjiang Kang, and et al.(2014) Dopamine release from transplanted neural stem cells in Parkinsonian rat striatum in vivo,  PNAS , doi/10.1073/pnas.1408484111