To this regard, a 2019 study showed that EVs from BV2 cells treated with IL-4 are neuroprotective in ischemic stroke, augmenting neuronal survival, and through other factors, such as fibroblast growth factor, nerve growth factor, and brain-derived neurotrophic factor (BDNF) (Song et al., 2019) (Figure 3). The gene discussed is BDNF; the disease is ischemic stroke.