Extraocular Blood Flow and Endothelin-1 Plasma Levels in Patients with Multiple Sclerosis

In order to evaluate whether plasma levels of the potent vasoconstrictor endothelin-1 (ET-1) are increased in patients with multiple sclerosis (MS) and whether these patients exhibit an ET-1-mediated vascular dysregulation, ET-1 plasma levels were measured in 30 patients with MS. Blood flow velocities in the ophthalmic artery, central retinal artery, central retinal vein, short lateral posterior ciliary artery, and short medial posterior ciliary artery were assessed in parallel. ET-1 plasma levels were significantly increased in MS patients when compared to sex- and age-matched healthy controls (2.0 +/- 0.4 pg/ml, range 1.1-2.8 vs. 1.5 +/- 0.2 pg/ml, range 0.9-2.0; p < 0.001). Moreover, the patients exhibited significant alterations of extraocular blood flow. The role of ET-1 in the inflammatory process remains to be clarified.