Multipotent progenitor cells (MPCs), developed by Dr. Verfaillie and co-workers at the University of Minnesota, appear to have the properties which make them highly suitable as a stem cell therapy. Athersys, Inc. has the proprietary rights to these cells. We have recently developed a collaborative relationship with Athersys, Inc. which has developed manufacturing techniques to make these cells available for clinical use. Athersys, Inc. will supply these cells to us. Our preliminary data in rodents indicate that these cells are quite promising as a therapy for stroke. In order to develop the utility of these cells in stroke, we propose a translational protocol. The proposed set of experiments will serve as the preclinical basis for proceeding with transplantation of MPCs in ischemic stroke patients. Feasibility, safety, and optimal MFC dose and transplantation timing poststroke for producing efficacy in rodent models of adult ischemic stroke will be examined. The following specific aims will serve as milestones, with "go and no-go" criteria. ¿ Specific Aim 1: Determine the "long-term" (i.e., 6 months post-transplantation) efficacy of IV rat MPCs in transient middle cerebral artery occlusion model. ¿ Specific Aim 2: Evaluate the long-term efficacy of IV human MPCs produced by Athersys, Inc. according to GMP manufacturing protocols in a GLP xenogeneic transient middle cerebral artery occlusion model. ¿ Specific Aim 3: Assess the efficacy of IV human MPCs to achieve long-term behavioral benefits in male and female, and adult and aged rats exposed to transient middle cerebral artery occlusion model. ¿ Specific Aim 4: Demonstrate the efficacy of IV human MPCs to achieve long-term behavioral benefits in permanent middle cerebral artery ligation model. ¿ Specific Aim 5: Characterize stem cell histocompatibility in allogeneic rat MPCs and xenogeneic human MPCs to further provide safety of IV MPCs in rat ischemic stroke model. ¿ Specific Aim 6: Conduct IND FDA preparation meetings and assemble documents for filing IND for stem cell therapy in ischemic stroke. This proposal extends our scientific platform for determining the benefit of stem cell therapy in stroke.