DEVELOPING A REGENERATIVE MEDICINE APPROACH FOR THE TREATMENT OF PARKINSON'S DISEASE
Creators: name: CARELLI, STEFANA
Publisher: name: Universit� degli Studi di Milano
Year: 2014

description: Parkinson?s disease (PD) is the second most common neurodegenerative disease, after Alzheimer?s disease, and the most common movement disorder. Drug treatment and deep brain stimulation can ameliorate symptoms, but the progressive degeneration of dopaminergic neurons in the substantia nigra eventually leads to severe motor dysfunction. While some effective treatments for patients with PD exist, these treatment strategies are mainly symptomatic and aimed at increasing dopamine levels in the degenerating nigrostriatal system. Existing drugs are limited in their relief and decrease in effectiveness as PD progresses.The transplantation of stem cells has emerged as a promising approach to replace lost neurons in order to restore dopamine levels in the striatum and reactivate functional circuits. Post mortem neural precursor cells (PM-NPCs) are a subclass of sub ventricular zone (SVZ)-derived neural progenitors, capable of surviving many hours (16 hours) after donor death. The in vitro differentiation yields more neurons (about 30-40%) compared to regular NPCs (Marfia et al., 2011). Recently from the SVZ of a transgenic mouse strain expressing green fluorescent protein (GFP) under the promoter C of the ubiquitin gene [(C57BL/6-Tg(UBC-GFP)30Scha/J)] we isolated GFP PM-NPCs, from mice at 6 hours after the donor death. These cells were characterized and their potential of in terms of replacement therapy was investigated in a mouse model of Parkinson disease. The degeneration of dopaminergic neurons was obtained through the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) at the dosage of 36 mg/kg intraperiteoneally (i.p.). After 1 week the lesion was stabilized by a second administration (i.p.) of the neurotoxin at the dosage of 20 mg/kg. 1x 105 of PM-PCs-GFP were injected unilaterally into the striatum of C57/BL mice by using specific stereotaxic coordinates 3 days after the second MPTP administration. The effects of transplanted cells were determined by means of performance tests aimed at detecting behavioral improvements. Moreover, the neurochemical changes were also studied by high performance liquid chromatography (HPLC). In order to study the in vivo fate of grafted GFP PM-NPCs animals were perfused 2 weeks after transplantation and immunohistochemistry studies were performed. Our results show that animals grafted with GFP PM-NPCs determined a remarkable improvement of behavioral parameters measured by means of both horizontal and vertical grid tests (forepaw fault and time required to grab on the grids while turning and climbing down) since the third day after transplantation. These improvements were very significant and the average values were close to control animals. This was maintained during all the two weeks of experimental observation. By means of immunofluorescence staining we observed that the majority of transplanted GFP-PM-NPCs were vital and able to migrate ventrally and caudally from the injection site lengths as far as 1000 microns into the striatum, and could reach the ipsilateral and contralateral substantia nigra pars compacta. Moreover, morphological analyses revealed that transplanted cells in the striatum are able to differentiate into tyrosine hydroxylase (40%), cholinergic (40%), and gabaergic neurons (25%). This study provides new evidences that PM-NPCs will be useful for developing cellular PD therapies. Future studies should further explore the clinical potential role of the investigated post mortem neural precursors cells in order to provide new perspectives for PD treatment.