Regenerative Cellular Therapies for Neurologic Diseases

The central nervous system has limited regenerative capacity after injury, often leading to permanent disability. Stem cell trials offer potential treatments to restore lost neurologic function due to disease, maldevelopment, or trauma. Stem cells could restore function by replacing lost cells, differentiating into the needed cell type, and reconnecting with local circuits. They can also provide neuroprotective effects by secreting growth factors and stimulating anti-oxidants. Current regenerative neurology efforts primarily focus on promoting a supportive local environment for the function of remaining neuronal circuits, rather than extensive cell replacement throughout the brain.

• 1
  In demyelinating diseases and spinal cord injury, the primary goal is to remyelinate intact axons. MSC infusions have shown some improvement in neurologic function, possibly through immunomodulation.
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  In ALS, the focus has shifted from replacing lost motor neurons to providing a supportive environment to preserve remaining neurons. Clinical trials have shown the safety of neural stem cell transplantation.
• 3
  For Parkinson's disease, the technology for producing dopaminergic neurons from pluripotent cells is advanced. Graft-induced dyskinesias have been a major side effect in fetal stem cell transplantation studies.