GDNF and stroke disorder: In addition, various neurotrophic factors secreted by astrocytes, such as nerve growth factor (NGF), brain-derived growth factor (BDNF), erythropoietin (EPO), vascular endothelial growth factor (VEGF), and glial derived neurotrophic factor (GDNF), are increased after stroke (Linnerbauer and Rothhammer, 2020).