The present invention provides compositions and methods for enhancing the neuroprotective effect of umbilical cord blood cells. More particularly, the present invention provides methods of treating neurodegenerative disorders by administering umbilical cord blood cells and a substance capable of permeabilizing the blood brain barrier. In one embodiment, the blood brain barrier permeabilizer is mannitol. In another embodiment, the blood brain barrier permeabilizer is Cereport.