Stem cells against Parkinson’s

Previous studies have developed an approach to derive midbrain dopaminergic neurons from human embryonic stem (hES) cells. Tabar et al. now use these cells in an open, phase 1 clinical trial aiming to treat Parkinson’s disease (PD).

The authors primarily assessed the safety and tolerability of bilateral grafts of cryopreserved dopaminergic neuron progenitor cells into the putamen of individuals with PD. Twelve patients were enrolled into two cohorts — five patients were subjected to low-dose treatment (0.9 × 10⁶ cells per putamen) and seven patients were subjected to high-dose treatment (2.7 × 10⁶ cells per putamen). Both cohorts underwent immunosuppression for a year. After 12 months, no major adverse events related to the transplant or immunosuppression were detected. Further studies showed that the transplanted dopaminergic neurons survived up to 18 months after transplantation. In addition, the high-dose cohort patients displayed an improvement in their PD symptoms.