Vascular endothelial dysfunction associated with severity in multiple sclerosis

Background: Impairment of cerebrovascular reactivity (CVR) has been reported in patients with multiple sclerosis (MS). Chronic inflammation and endothelial dysfunction are possible mechanisms underlying this hemodynamic impairment. This study aimed to evaluate CVR and endothelial function in patients with MS and explore their relationships with disease progression using functional sonographic procedures. Methods: Patients with MS and age-/sex-matched healthy controls were assessed for endothelial function, determined by flow-mediated dilation (FMD), and CVR, measured using the breath-holding index (BHI). Results: Twenty-seven patients with MS and 24 healthy controls were enrolled. FMD was significantly lower in MS subjects than in control subjects (6.0 +/- 0.6 vs. 8.6 +/- 0.7, p = 0.006); furthermore, BHI was similarly lower in MS than in controls, but insignificant. Remarkably, FMD was significantly lower in secondary progressive MS subjects than in relapse-remitting MS subjects (3.7 +/- 1.3 vs. 6.7 +/- 0.7, p = 0.045). In addition, FMD was inversely correlated with the disability score as per the expanded disability status scale (R2 = 0.170, p = 0.033) and modified Rankin scale (R2 = 0.187, p = 0.027). Conclusion: In patients with MS, endothelial dysfunction was more noticeable than CVR impairment, correlating with the severity and progression of MS.