Neural stem cells restore cognitive function in Parkinsonian macaques

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. Here 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. We show unprecedented recovery from cognitive symptoms in addition to a clear clinical motor recuperation. Motor and cognitive recovery but not circadian rhythm recovery correlated with the degree of graft integration into the host environment and with in-vivo levels of striatal dopaminergic transporters and function. This study provides empirical evidence that neural stem cells transplantation efficiently restore function at multiple levels in Parkinsonian non-human primates. We demonstrate the promising potential of multiple-sites neural stem cells grafts for Parkinson’s disease but furthermore underline the crucial importance of such multidisciplinary approaches for an effective clinical translation.