POST MORTEM NEURAL PRECURSORS CELLS THERAPEUTIC INTERVENTION PROMOTE NEURAL TISSUE SPARING AND RECOVERY OF FUNCTION IN CENTRAL NERVOUS SYSTEM NEURODEGENERATIVE MODELS.

Regenerative medicine is a branch of translational research focused on the discovery of new approaches for replacement of cells tissue and organs used to improve the recovery in neurodegenerative or traumatic disease. Spinal cord injury (SCI) is a debilitating clinical condition, characterized by a complex of neurological dysfunctions. ). SCI disabilities range from cognitive impairment to loss of sensation and partial to complete paralysis. We have isolated a subclass of neural progenitors, kept from SVZ 6 hours after animal death capable of surviving a powerful ischemia insult. These cells were named Post Mortem Neural Precursors Cells (PM-NPCs). Differentiation yield mostly neurons (about 30-40%) compared to regular NPCs (about 10-12%). Also the cholinergic yields is higher. Their EPO-dependent differentiation abilities produce a significantly higher percentage of neurons than regular NSCs. The potential of PM-NPCs in terms of replacement therapy was investigated in a mouse model of contusive spinal cord injury lesioned at T9 level with intensity equal to 70 kDyne, by means of Infinity Horizon Impactor device. 1x 106 PM-NPCs, were administered intravenously within two hours after the traumatic injury of the cord then the functional recovery and the fate of transplanted cells were studied. Animals transplanted with PM-NPCs showed a remarkable improved recovery of hind limb function evaluated by Basso Mouse Scale up to 90 days after lesion. This was accompanied by reduced myelin loss, counteraction of the invasion of the lesion site by the inflammatory cells, and an attenuation of secondary degeneration. PM-NPCs migrate mostly at the injury site, where they survive and differentiate predominantly into cholinergic neurons, reconstitute a rich axonal and dendritic network and favors preservation of myelin fibers and promotes tyrosine hydroxylase and serotonergic fiber formation at lesion site. Moreover, the molecular analysis of the lesion site show that PM-NPCs induce a modulation of inflammatory response and release of neurotrophic factors. Pro-inflammatory cytokines (IL-6, MIP-2 and TNF-alpha) levels significantly decrease after 48 hours from spinal cord injury and PM-NPCs transplantation. Moreover, our results show that transplantation of PM-NPCs facilitated significant axonal sparing/regeneration. This is associated with an increased amount of intact tissue at the lesion site. Anterograde tracing revealed statistically significant increased numbers for supraspinal tracts in PM- NPCs treated animals. Consequently, axons that regenerate across the lesion bridge and reach the caudal interface may mediate improvement in hindlimb movement Cell therapies has been proposed as a regenerative approach to compensate the loss of specific cell populations in neurodegenerative disorders, where symptoms can be ascribed to the degeneration of a specific cell type. Parkinson’s disease (PD) is the second most common neurodegenerative disease, caused by midbrain dopaminergic neurons degeneration in the Substantia Nigra (SN). Stem cell transplantation has emerged as a promising therapeutic approach. The other aim of this work was to evaluate the curative effects of PM-NPCs in a mouse model of PD. The degeneration ofdopaminergic neurons was obtained with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in C57BL/6 mice at the dosage of 36 mg/kg intraperiteoneally. Then the lesion was stabilized by a second injection (i.p.) of the drug at the dosage of 20 mg/kg. 1x 105 of PM-PCs-GFP were administered to C57/BL mice by stereotaxic injection unilaterally in the left striatum 3 days after the second MPTP administration. The effects of transplanted cells were determined by means of performance tests aimed at detecting behavioral improvements. Our results show that animals treated with GFP-PM-NPCs had a remarkable improvement of parameters measured by means of both horizontal, vertical grid and olfactory tests starting with the third day after transplantation. These improvements were very significant and the average values were close to control. This was maintained throughout two weeks of experimental observation. This was likely promoted by PM-NPCs-derived erythropoietin (EPO), since the co-injection of cells with anti-EPO or anti-EPOR antibodies had completely neutralized the positive outcome. At the end of observational period, most of the transplanted PM-NPCs were vital, and were able to migrate ventrally and caudally from the injection site, reaching the ipsilateral and contralateral Substantia Nigra. Transplanted cells were differentiated into dopaminergic, cholinergic, and gabaergic neurons. In conclusion, we purified a new class of neural precursors able to survive after a powerful ischemic insult (PM-NPCs). We found that treatment with PM-NPCs can limit the effects of degeneration of the injury both in the spinal cord and in Parkinson’s disease. For these reasons these cells represent a liable source for cellular therapy in neurodegenerative disorders, especially on spinal cord injury and Parkinson’s disease.