Feng et al. (2014) demonstrated that the neuroprotective effect of neuropeptide orexin-A in an in vitro PD model could be explained by HIF-1α induction, followed by the expression of its downstream targets, including VEGF and EPO. Systemic EPO administration also modulates long-term synaptic plasticity (Almaguer-Melian et al., 2016), has antioxidant effects when injected into the striatum (but not into the substantia nigra), and reduces inflammatory responses (Thompson et al., 2020). This evidence concerns the gene VEGFA and Parkinson disease.