Neural stem cells restore motor and cognitive function in a macaque model of Parkinson's disease

Cognitive deficits as well as disorders of sleep and biological rhythms constitute non-motor symptoms that significantly impact quality of life in Parkinson's disease patients. Few studies have evaluated the impact of cell replacement therapy on such non-motor symptoms. We used a multidisciplinary approach to assess the therapeutic potential of bilateral grafts of neural stem cells in a macaque model of Parkinson's disease on both motor and non-motor markers of functional recovery. Grafts led to varying degrees of functional recovery while sham experiments did not. Motor and cognitive but not circadian rhythm recovery correlated with the degree of graft integration into the host environment and dopaminergic function. Transplantation of neural stem cells thus restore function at multiple levels in the parkinsonian monkeys.