BDNF and Stroke: Recent studies have confirmed that MSCs are effective modifiers maintaining a resting microglial phenotype, preventing microglial activation by downregulating pro-inflammatory cytokines/chemokines and upregulating hypoxia-inducible factor 1-alpha (HIF-1α) and growth factors including VEGF, BDNF, GDNF, stromal-derived factor-1 (SDF-1), and erythropoietin (EPO) following stroke (Wei et al., 2012; Yan et al., 2013).