Stem cell therapy extends incubation and survival time in prion-infected mice in a time window-dependant manner.

Prion diseases, which are mostly represented in humans by Creutzfeldt-Jakob disease, are transmissible neurodegenerative disorders characterized by vacuolization and neuronal loss, as well as by the accumulation of an abnormal form of the prion protein. These disorders have yet no effective treatment, and drugs that block prion replication in vitro do not significantly slow down the progression of the disease when used in vivo at late stages. Cell therapy that has been already tested in other neurodegenerative disorders therefore represents an interesting alternative approach. In this study, we showed for the first time in prion diseases that intracerebral transplantation of fetal neural stem cells significantly extended both incubation and survival time. This result was dependant on the time window chosen for the engraftment and was obtained with both genetically modified and wild-type stem cells, therefore forging a path toward efficient stem cell therapy for human prion diseases.