CXCL12 and ischemia: Reactive astrocytes express various neurovascular trophic factors and chemokines such as SDF-1α, VEGF, glial cell derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF), which may positively contribute to neurogenesis, angiogenesis and neurite outgrowth following ischemia (54).