Intravascular stem cell transplantation for stroke.

Stroke is the third leading cause of death and the leading cause of adult disability in North America. Emphasis has been placed on developing treatments that reduce the devastating long-term impacts of this disease, and preclinical research on stem cell therapy has demonstrated promising results. However, questions about the optimal cell delivery method and timing of cell transplantation are not fully answered. Recent findings suggest that intravascular stem cell delivery is a safe and efficacious alternative to stereotactic cell injections. It also offers advantages should repeat treatments prove beneficial. Recent reports further suggest that intra-arterial injection results in a wider distribution of cells throughout the stroked hemisphere with a significantly greater cell engraftment compared to intravenous injection. In this review, we describe the benefits and potential risks associated with intravascular stem cell delivery and compare intra-arterial to intravenous cell transplantation methods. We discuss the importance of cell biodistribution and timing of transplantation in driving cell survival. We examine current proposed mechanisms involved in cell migration and functional recovery and discuss future directions for intravascular stem cell therapy research.