Angiogenic Recruitment of Pericytes from Bone Marrow after Stroke

Abstract
Bone marrow-derived cells (BMDCs) contribute to revascularization after ischemia. However, the mechanisms by which BMDCs support vessel remodeling after cerebral ischemia are not clear. Using mouse chimeras that express enhanced green fluorescent protein in reconstituted bone marrow, we investigated the role of BMDCs in revascularization and brain repair after middle cerebral artery occlusion of murine brain. After ischemia, two populations of BMDCs were observed, one in the brain parenchyma and another associated with the vasculature. The number of BMDCs that infiltrated the brain parenchyma peaked at 7 days and persisted through 14 days, the last time point observed. The majority of BMDCs were characterized as microglia, based on cell-type-specific marker expression. We observed a robust angiogenic response after cerebral ischemia. Bone marrow-derived cells associated with remodeling blood vessels were negative for endothelial markers, but were surrounded by basal lamina and expressed desmin and vimenti...