Inflammatory changes induced by transplanted neural precursor cells in a multiple sclerosis model.

Recent studies on neural precursor cell (NPC) transplantation in multiple sclerosis animal models reveal that these cells exert their therapeutic effect mainly because of immunomodulation rather than cell replacement. In this study intraventricularly transplanted NPCs in mice, induced experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis, improved the clinical symptoms and suppressed inflammation in the brain by enhancing the apoptosis of inflammatory cells. However, the same treatment failed to reduce significantly the inflammatory cells in the spinal cord, the pathology of which predominantly determines the clinical manifestation of experimental autoimmune encephalomyelitis. Our findings suggest that immunosuppression is rather a local phenomenon and thus, bystander neuroprotective mechanisms triggered by NPC intraventricular transplantation should be accountable for their therapeutic effect.