Cerebral autoregulation in migraine with aura: A case control study.

BACKGROUND: Migraine with aura is independently associated with increased risk of ischemic stroke, especially in younger subjects. This association might be related to an impairment of cerebral autoregulation, which normally maintains cerebral blood flow independent of arterial blood pressure variations. METHODS: Patients aged 30-55, fulfilling ICHD-3 beta criteria for migraine with aura, were prospectively enrolled and compared with gender- and age-matched healthy controls without a history of migraine. Patients and controls with a history of stroke or any disease potentially impairing cerebral autoregulation were excluded. We assessed cerebral autoregulation with two different methods: Transfer function analysis, and the correlation coefficient index Mx. The transfer function phase and gain reflect responses of cerebral blood flow velocities to relatively fast fluctuations of arterial blood pressure, whereas Mx also reflects responses to slower arterial blood pressure fluctuations. RESULTS: A total of 22 migraine with aura patients (median age [IQR]: 39.5 [12.5] years) and 22 controls (39 [9.75] years) were included. Transfer function parameters and Mx were not different between patients and controls. However, Mx was inversely correlated with age in patients (ρ = -0.567, p = 0.006) and not in controls (ρ = -0.084, p = 0.509). Mx was also inversely correlated with migraine with aura duration (ρ = -0.617, p = 0.002), suggesting improvement of cerebral autoregulation efficiency with disease duration. CONCLUSIONS: Cerebral autoregulation did not differ between patients and controls aged 30-55. However, cerebral autoregulation efficiency was strongly correlated with migraine with aura duration. Further studies in younger patients are needed to determine whether cerebral autoregulation is impaired early in the course of disease. TRIAL REGISTRATION: NCT02708797.

Simvastatin decreases levodopa-induced dyskinesia in monkeys, but not in a randomized, placebo-controlled, multiple cross-over ("n-of-1") exploratory trial of simvastatin against levodopa-induced dyskinesia in Parkinson's disease patients.

BACKGROUND: Simvastatin may improve levodopa-induced dyskinesia through striatal Ras-extracellular signal-regulated kinase pathway modulation. METHODS: (1) Six 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated macaques were assessed for parkinsonism and dyskinesia severity following acute co-administration of levodopa and simvastatin (0, 1.5, 3 and 6 mg/kg). (2) A "n-of-1" design randomized, placebo-controlled, 3 cross-over trial was then conducted in 10 Parkinson's disease patients with troublesome dyskinesia. The primary endpoint was a 7-point scale rating subjective discomfort caused by troublesome dyskinesia. Secondary endpoints related to dyskinesia severity and duration and functional impairment, severity and duration of OFF periods, motor scores and investigator- and patient-rated global impressions. (3) The pharmacodynamic variable for both studies consisted in a multiplex analysis of kinase-induced phosphorylation in T and B-lymphocytes by flow cytometry. RESULTS: (1) In the macaque, simvastatin reduced dyskinesia scores (45%), at the dose of 3 mg/kg (2) In the "n-of-1" trial no significant response was observed in the primary end point and all secondary endpoints. No serious adverse events were reported. (3) Simvastatin 3 mg/kg significantly reduce kinase-induced phosphorylation in monkeys but not simvastatin 40 mg in patients. CONCLUSIONS: Simvastatin reduced dyskinesia in primates using high doses over 3 mg/kg but the exploratory trial in patients revealed no effect at 40 mg/d suggesting that higher doses, not compatible with a safe prolonged administration, are necessary.