Abstract 2981: Transplantation of Embryonic Stem Cell Derived Endothelial Cells Promote Functional Recovery after Cerebral Ischemia
Background: Stroke is a leading cause of death and a majority of stroke survivors have functional impairment. Preliminary observations suggest that neural stem cell transplantation may be a viable stroke cell therapy. However, as neuronal regeneration will require concomitant vascular regeneration, we studied the effects of transplantation of ESC-derived endothelial cells(ECs). Ultimately, we hope to elucidate how ESC-derived ECs respond to the ischemic brain, mobilize, integrate, and reconstitute the complex neurovascular architecture and interaction.
Methods: We first developed a high throughput method to promote endothelial lineage, and to detect ESC-derived ECs. Mouse ESCs were genetically modified to stably express the EC specific promoter for VE-Cadherin driving a GFP reporter gene, and genes for bioluminescence and PET. Endothelial cell lineage was induced by sequential culture and purification steps of differentiating ESCs. Endothelial lineage was further confirmed by examining endothelial specific markers. Adult male Sprague-Dawley rats (n = 20) were anesthetized and focal cerebral ischemia was induced using suture-induced middle cerebral artery occlusion (MCAO). Two hours after occlusion, ESC derived ECs were injected through common carotid artery. Bioluminescence imaging and PET were performed using the Xenogen In Vivo Imaging System and microPET. Coronal sections of the brain were made for immunohistochemistry.
Results: 1, 3,7, 14,21, and 28 days after cell transplantation, we observed bioluminescence in the region of the lesion. Furthermore, we observed GFP positive cells in the luminal lining of some small vessels in the ischemic area by immunohistochemistry 7 days after cell transplantation. Mortality was reduced, and neurobehavioral testing in the survivors tended to be improved in transplanted animals.
Conclusion: ESC derived endothelial cells were able to integrate into the vasculature of a region of cerebral ischemic injury, associated with an improvement in function and mortality. These preliminary observations provide a rationale for further examination of this approach.