They didn't have an explanation for the significantly elevated ET-1 levels in MS patients in 2001. It appears we now know the cause....CCSVI.
J Neuroophthalmol. 2001 Mar;21(1):37-8.
Increased endothelin-1 plasma levels in patients with multiple sclerosis.
Haufschild T, Shaw SG, Kesselring J, Flammer J.
University Eye Clinic, Basel, Switzerland.
OBJECTIVE: We tested the hypothesis that the plasma level of endothelin-1 (ET-1) is increased in patients with multiple sclerosis (MS). The peptide ET-1 is one of the most potent known vasoconstrictors. An increased level of endothelin could explain some of the vascular symptoms of these patients.
MATERIALS AND METHODS: A specific radioimmunoassay was used to determine ET-1 plasma levels. Twenty patients with MS were compared to 20 age- and sex-pair-matched healthy subjects.
RESULTS: The plasma ET-1 levels were, on average, 224% higher in the patients with MS than in the controls
(p < 0.005). The mean ET-1 levels (mean +/- standard deviation [SD]) were 3.5 +/- 0.83 pg/mL (min 2.13, max 5.37 pg/mL) in patients with MS and 1.56 +/- 0.3 pg/mL (min 0.9, max 2.13 pg/mL) in healthy volunteers. Neither the different forms nor stages of MS had an influence on the results. The ET-1 level was also not correlated with the duration of the disease.
CONCLUSIONS: The plasma ET-1 level is markedly and significantly increased in patients with MS.
Neither the cause of such an increase nor the pathogenetic role is known.