Donor-derived vasculature is required to support neocortical cell grafts after stroke

Neural precursor cells (NPCs) transplanted into the adult neocortex generate neurons that synaptically integrate with host neurons, supporting the possibility of achieving functional tissue repair. However, poor survival of transplanted NPCs greatly limits efficient engraftment. Here, we test the hypothesis that combining blood vessel-forming vascular cells with neuronal precursors improves engraftment. By transplanting mixed embryonic neocortical cells into adult mice with neocortical strokes, we show that transplant-derived neurons synapse with appropriate targets while donor vascular cells form vessels that fuse with the host vasculature to perfuse blood within the graft. Although all grafts became vascularized, larger grafts had greater contributions of donor-derived vessels that increased as a function of their distance from the host-graft border. Moreover, excluding vascular cells from the donor cell population strictly limited graft size. Thus, inclusion of vessel-forming vascular cells with NPCs is required for more efficient engraftment and ultimately for tissue repair.