Cells of bone marrow origin give rise to endothelial cells in the brain following ischemia-induced damage. HSC indicates hematopoietic stem cell; MSC, multipotent stromal cell; EPC, endothelial progenitor cell; ?, uncertainly as to the nature of the bone marrow cell that gives rise to brain endothelium and as to the exact target for the action of granulocyte colony-stimulating factor (G-CSF) and stem-cell factor (SCF).