In vivo multimodal imaging of stem cell transplantation in a rodent model of Parkinson's disease.

Stem cell therapy in the nervous system aims to replace the lost neurons and provide functional recovery. However, it is imperative that we understand the in vivo behaviour of these cells post-implantation. We report visualisation of iron oxide labelled bone marrow-derived stem cells (BMSCs) implanted into the striatum of hemi-parkinsonian rats by magnetic resonance imaging (MRI). Functional efficacy of the donor cells was monitored in vivo using the positron emission tomography (PET) radioligand [11C]raclopride. The cells were visible for 28 days by in vivo MRI. BMSCs provided functional recovery demonstrated by a decreased binding of [11C]raclopride. Although, histology confirmed the persistence of donor cells, no tyrosine hydroxylase positive cells were present. This suggests that BMSCs may have a limited paracrine effect and influence functional recovery. We demonstrate, using multimodal imaging, that we can not only track BMSCs but also establish their effects in a pre-clinical model of Parkinson's disease.