Patients with MS present an impaired capacity to dilate cerebral arterioles (Marshall et al., 2014; Nie & Olsson, 1996; Ostrow et al., 2000), suggesting that vasoconstriction resulting from ET1 released by reactive astrocytes could contribute to hypoperfusion in MS (D'Haeseleer et al., 2015). This evidence concerns the gene EDN1 and myeloid sarcoma.