CAT and Parkinson disease: Based on efficient catalase delivery of BBB crossing macrophages to neuronal cells after systemic administration in a PD mouse model [143] and the identification of EV mediated catalase transfer in this process [144], macrophage EVs for brain drug delivery were also further explored by Haney et al. Especially since the authors expected macrophage derived EVs would have a higher capacity to avoid entrapment by mononuclear phagocytes, this EV type might display a prolonged circulation time and hence improved therapeutic efficacy [91].