An important molecular mechanism is as follows: reactive astrocytes release a damage-associated molecule known as HMGB1 and up-regulate HMGB1 in the peri-infarct cortex after ischemic stroke, which can raise EPC levels, and then increase peri-infarct angiogenesis to reduce the worsening of neurological deficits. Here, HMGB1 is linked to ischemic stroke.