A paralyzed man with severe spinal injury regains use of his arms and hands after experimental stem cell therapy.

The stem cells are converted into oligodendrocytes, which are a type of glial cell found in the brain and spinal cord that support the healthy functioning of nerve cells. The oligodendrocytes then produce critical factors (such as myelin) for the survival, regrowth, and conduction of nerve impulses through axons at the site of injury.