KITLG and Stroke: Environments associated with acquired neurological injury such as stroke and spinal cord injury have been shown to promote endogenous stem cell differentiation [9, 66, 67] and this effect may be mediated, in part, by trophic and cytokine signals such as stem cell factor [68], stromal cell-derived factor 1α [69], FGF-2 [70], vascular endothelial growth factor [71], ciliary neurotrophic factor, and CXC chemokine receptor 4 [72].