Yang et al. compare in this article intravenous (IV) versus intrarterial (IA) administration of autologous bone marrow mononuclear cells (MNCs) in a rat model of transient middle cerebral artery occlusion. In this study, rats received either low dose or high dose MNCs, after stroke lesion, either through IV or IA administration. Neurologic outcomes, serum cytokines and neuropathology techniques were used to compare the routes of administration. They found that IA delivery was not superior to IV at most endpoints. For example, lesion size was reduced in rats receiving high dose MNCs, and did not matter if therapy was received IA or IV.

This is provocative work; in that it demonstrates with systemic administration of MNCs, there may be adequate entry into the brain. IV administration is much more practical than IA in the clinical setting. The idea that autologous stem cells will “hone in” on damaged brain tissue after bypassing the lungs and the rest of the systemic circulation is remarkable. I for one am amazed that the cells are even able to get to the target damaged brain tissue. I would like to better understand the hypothesis as to how they will help in network repair and functional recovery after they arrive. Would delivering cytokines and growth factors to the damaged brain have the same effect, or is there an integrative function that the cells play themselves? Either way, the idea of a new high technology therapy for stroke recovery is appealing, and we will continue to watch.