Human stem cells for the treatment of motorneuron diseases: regenerative potential, translatability and development of new biotechnologies. Cellule staminali umane per la cura delle malattie degenerative del motoneurone

Stem cell therapy is considered one of the most promising approaches against different neurodegenerative disorders, including Amyotorophic Lateral Sclerosis (ALS). The evidence that the systemic injection of human cord blood mononuclear cells (HuCB-MNC) was able to reduce the clinical outcomes and increase the lifespan in a murine model of fALS1, the SOD1G93A mouse, even if localized far from affected motor neurons, opens the way for new possible candidates and alternative ways of administration. Here the effect of human skeletal muscle-derived stem cell (SkmSCs) was investigated by single administration in lateral ventricles in the most characterized model of spontaneous motor neuron degeneration, the Wobbler (Wr) mouse. Before evaluating clinical progression, we found that SkmSCs (previously labeled with the super paramagnetic contrast agent Endorem™ and/or with the fluorescent nuclear dye Hoeschst 33258): 1) spread along the whole ventricular system as far as the ependymal canal at the spinal cord level; 2) remained for a longer time in the Wr than in the healthy mice, and; 3) did not significantly migrate to the parenchyma. Similar to the SOD1G93A mice treated with HuCB-MNCs, the transplantation of SkmSCs: 1) significantly improved the disease progression of ALS-related Wr motorneuropathology; 2) this effect was not associated with a migration of SkmSCs close to the degenerating motor neurons. Very interestingly, we also found that cell grafting in the Wr brain ventricles significantly increased the gene expression of anti-inflammatory cytokines or chemokines activated in the inflammatory response. These results further confirm the consistency of the hypothesis of the bystander effect of stem cells in motor neurodegenerative disorders by a mechanism of action aimed at reducing the neuroinflammatory response.