Cerebrovascular reactivity to l-arginine in the anterior and posterior cerebral circulation in migraine patients

Association between vertebral artery dominance and basilar artery curvature in migraineurs: an anatomical magnetic resonance imaging study

BACKGROUND AND PURPOSES

Numerous studies demonstrate a link between cerebrovascular alterations and migraine pathogenesis. We investigated the association between migraine and vertebral artery dominance (VAD), basilar artery (BA) curvature, and elongation.

MATERIALS AND METHODS

This cross-sectional MRI study included 74 migraine patients and 74 control subjects aged between 18 and 55 years. Diameters of the intracranial part of the vertebral artery (VA) and BA, height of the BA bifurcation, and total lateral displacement of the BA were measured. In addition, we investigated the directional relationship between VAD and BA curvature.

RESULTS

There were no statistically significant differences between the groups regarding VA and BA diameters and total lateral displacement of the BA. The height of the BA bifurcation was found to be significantly higher in migraine patients compared to controls (p = 0.002). The left-side VAD was more frequent in migraine patients compared to control subjects (60.8% (45/74) vs 41.9% (31/74), p = 0.001). In migraine patients, particularly those with aura (MwA) patients, with left-side VAD, the rate of BA displacement to the right side is significantly higher than those with right-side VAD or non-VAD (p = 0.022). Also, we found that total lateral displacement of the BA is correlated with VA asymmetry in patients with MwA (r = 0.538, p = 0.007).

CONCLUSION

VAD and its opposite-directional relationship with the lateral displacement of the BA may be associated with migraine pathophysiology. Together with aging, this association may contribute to changes in the vertebrobasilar system (VBS) geometry which may result in increased risk for posterior circulation infarction (PCI) in migraineurs.

Dysregulation of Amino Acid, Lipid, and Acylpyruvate Metabolism in Idiopathic Intracranial Hypertension: A Non-targeted Case Control and Longitudinal Metabolomic Study

Background: Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure occurring predominantly in women with obesity. The pathogenesis is not understood. We have applied untargeted metabolomic analysis using ultrahigh-performance liquid chromatography-mass spectrometry to characterize the cerebrospinal fluid (CSF) and serum in IIH compared to control subjects. Methods and findings: Samples were collected from IIH patients (n = 66) with active disease at baseline and again at 12 months following therapeutic weight loss. Control samples were collected from gender- and weight-matched healthy controls (n = 20). We identified annotated metabolites in CSF, formylpyruvate and maleylpyruvate/fumarylpyruvate, which were present at lower concentrations in IIH compared to control subjects and returned to values observed in controls following weight loss. These metabolites showed the opposite trend in serum at baseline. Multiple amino acid metabolic pathways and lipid classes were perturbed in serum and CSF in IIH alone. Serum lipid metabolite pathways were significantly increased in IIH. Conclusions: We observed a number of differential metabolic pathways related to amino acid, lipid, and acylpyruvate metabolism, in IIH compared to controls. These pathways were associated with clinical measures and normalized with disease remission. Perturbation of these metabolic pathways provides initial understanding of disease dysregulation in IIH.

Cumulative effect of simvastatin, L-arginine, and tetrahydrobiopterin on cerebral blood flow and cognitive function in Alzheimer's disease

BACKGROUND AND OBJECTIVES

Vascular disease is a known risk factor for Alzheimer's disease (AD). Endothelial dysfunction has been linked to reduced cerebral blood flow. Endothelial nitric oxide synthase pathway (eNOS) upregulation is known to support endothelial health. This single-center, proof-of-concept study tested whether the use of three medications known to augment the eNOS pathway activity improves cognition and cerebral blood flow (CBF).

METHODS

Subjects with mild AD or mild cognitive impairment (MCI) were sequentially treated with the HMG-CoA reductase synthesis inhibitor simvastatin (weeks 0-16), L-arginine (weeks 4-16), and tetrahydrobiopterin (weeks 8-16). The primary outcome of interest was the change in CBF as measured by MRI from baseline to week 16. Secondary outcomes included standard assessments of cognition.

RESULTS

A total of 11 subjects were deemed eligible and enrolled. One subject withdrew from the study after enrollment, leaving 10 subjects for data analysis. There was a significant increase in CBF from baseline to week 8 by ~13% in the limbic and ~15% in the cerebral cortex. Secondary outcomes indicated a modest but significant increase in the MMSE from baseline (24.2±3.2) to week 16 (26.0±2.7). Exploratory analysis indicated that subjects with cognitive improvement (reduction of the ADAS-cog 13) had a significant increase in their respective limbic and cortical CBF.

CONCLUSIONS

Treatment of mild AD/MCI subjects with medications shown to augment the eNOS pathway was well tolerated and associated with modestly increased cerebral blood flow and cognitive improvement.

TRIAL REGISTRATION

This study is registered in https://www.

CLINICALTRIALS

gov ; registration identifier: NCT01439555; date of registration submitted to registry: 09/23/2011; date of first subject enrollment: 11/2011.

Cerebrovascular function in tension-type headache and migraine with or without aura: Transcranial Doppler study

The aim of the current study was to determine whether tension-type headache (TTH) and migraine with or without aura have altered anterior and posterior circulation compared with normal volunteers as assessed by Transcranial Doppler (TCD) ultrasonography. The study included 24 patients with chronic TTH and 37 patients with migraine (16 with aura and 21 without aura) classified according to the diagnostic criteria of the International Headache Society 2018. They were compared with a control group of 50 age- and sex-matched healthy volunteers. Each participant was examined with TCD ultrasonography of the middle, anterior and posterior cerebral and vertebral arteries (MCA, ACA, PCA, and VA) at rest. Patients in the TTH group had a significantly lower peak systolic velocity (PSV) and mean flow velocity (MFV) in the MCA compared with controls, whereas EDV and MFV in the ACA were significantly higher in the migraine without aura group than controls. Within the 3 groups of patients, the TTH group had significantly lower PSV in the MCA and PCA than the group of migraine with aura. In addition, the TTH group had significantly lower PSV and MFV in the MCA and a lower EDV in the VA than migraine patients without aura. In conclusion, the possibility of cerebrovascular changes is confirmed in the present study in both TTH and migraine without aura. The former has a low MFV in the MCA whereas the latter has a high MFV in the ACA.

Migraine-Associated Common Genetic Variants Confer Greater Risk of Posterior vs. Anterior Circulation Ischemic Stroke☆

OBJECTIVE

To examine potential genetic relationships between migraine and the two distinct phenotypes posterior circulation ischemic stroke (PCiS) and anterior circulation ischemic stroke (ACiS), we generated migraine polygenic risk scores (PRSs) and compared these between PCiS and ACiS, and separately vs. non-stroke control subjects.

METHODS

Acute ischemic stroke cases were classified as PCiS or ACiS based on lesion location on diffusion-weighted MRI. Exclusion criteria were lesions in both vascular territories or uncertain territory; supratentorial PCiS with ipsilateral fetal posterior cerebral artery; and cases with atrial fibrillation. We generated migraine PRS for three migraine phenotypes (any migraine; migraine without aura; migraine with aura) using publicly available GWAS data and compared mean PRSs separately for PCiS and ACiS vs. non-stroke control subjects, and between each stroke phenotype.

RESULTS

Our primary analyses included 464 PCiS and 1079 ACiS patients with genetic European ancestry. Compared to non-stroke control subjects (n=15396), PRSs of any migraine were associated with increased risk of PCiS (p=0.01-0.03) and decreased risk of ACiS (p=0.010-0.039). Migraine without aura PRSs were significantly associated with PCiS (p=0.008-0.028), but not with ACiS. When comparing PCiS vs. ACiS directly, migraine PRSs were higher in PCiS vs. ACiS for any migraine (p=0.001-0.010) and migraine without aura (p=0.032-0.048). Migraine with aura PRS did not show a differential association in our analyses.

CONCLUSIONS

Our results suggest a stronger genetic overlap between unspecified migraine and migraine without aura with PCiS compared to ACiS. Possible shared mechanisms include dysregulation of cerebral vessel endothelial function.

The Responses to CGRP in the Territory of the Posterior Cerebral Artery in Migraine

Calcitonin gene-related peptide (CGRP) is important in trigeminovascular (TMV) sensitization with neurogenic inflammation which might be involved in CGRP-induced headache (CGRP-IH). Distribution of white matter lesions, migraine aura, and functional neuroimaging indicate that posterior circulation is especially exposed to TMV sensitization. The transcranial Doppler (TCD) is able to detect changes in the posterior cerebral artery (PCA) during CGRP stimulation. Thus, we studied CGRP-induced hemodynamic changes in PCA and frequency of CGRP-IH. Twenty healthy subjects and 20 patients with migraine participated in our study. TCD was used to monitor mean arterial velocity in posterior cerebral artery (v_mPCA). Simultaneously, end-tidal carbon dioxide (Et-CO₂), mean arterial pressure (MAP), and heart rate (HR) were measured. During the experiment, we monitored the frequency of CGRP-IH. We determined the values of v_mPCA, Et-CO₂, MAP, and HR and calculate the response of v_mPCA, Et-CO2, MAP, and HR to CGRP. To test the differences and relationships, statistical methods were applied using SSPS. We found significant decrease in v_mPCA in migraine and control groups and found the v_mPCA response to be significantly lower in migraine (p = 0.018). Et-CO₂ decreases in both groups, and it is significantly lower in migraine (p < 0.001). MAP is significantly higher in migraine (p = 0.001), while HR is not significantly higher in migraine (p = 0.570). CGRP-IH is significantly associated with v_mPCA responses (p = 0.003) and migraine (p < 0.001). We concluded that hemodynamic changes in PCA are significantly related to CGRP-IH. The TMV sensitization might be pronounced in posterior circulation explaining clinical and morphologic issues in migraine.

The Vasodilatory Response to CGRP of the Anterior and Posterior Cerebral Circulation in Migraine

Introduction

Migraine aura can be associated with headache or it may occur without one, which suggests an independent mechanism for the aura and for migraine headache. The role of CGRP in migraine headache is well established, but the connection between CGRP and the aura is still lacking an explanation. Exogenous CGRP can induce CGRP headaches and migraine auras in patients with migraine. The results of our recent study suggest differences in the vascular response to CGRP stimulation between migraine without aura and migraine with aura. Therefore, we hypothesized that the magnitude of the posterior cerebral circulation response in migraine with aura is greater than in migraine without aura and that CGRP stimulation has different effects on the anterior and posterior circulation in migraine with aura and migraine without aura.

Methods

By using transcranial doppler, we studied the hemodynamic effects of CGRP intravenous infusion at a rate of 1.5 mcg/min in 20 min on the mean arterial velocity in the middle cerebral artery and in the posterior cerebral artery in twenty patients with migraine and in a control group of twenty healthy subjects. The same CGRP effects on cerebral hemodynamics were analyzed separately for the group of patients with migraine with aura and the group of patients with migraine without aura. Fifteen patients with migraine (75%) had migraine without aura and 5 patients (25%) had migraine with aura.

Results

We found that migraine has a significant impact on the vasodilatory response of the anterior (B = 4,249, SE = 1.023, r = 0.363, p < 0.001) and posterior cerebral circulation (B = 3.634, SE = 1.461, r = 0.227, p = 0.014). Migraine with aura was significantly associated with changes in the anterior (B = 2.558, SE = 0.880, r = 0.275, p = 0.005) and posterior cerebral circulation (B = 7.565, SE = 2,368, r = 0.359, p = 0.002), while migraine without aura was only significantly associated with changes in the anterior circulation. In addition, we established a significant impact of migraine with aura on VR PCA (B = 5.901, SE = 2,546, r = 0.291, p = 0.024).

Conclusion

We conclude that TVR in the posterior cerebral circulation might be enhanced in MA and that aura might be a consequence of TVR enhancement.

Compromised cerebrovascular reactivity in migraineurs with right-to-left shunts: a potential mechanism of white matter hyperintensities

OBJECTIVE

Our study aims to explore the changes of cerebrovascular reactivity (CVR) in migraineurs with right-to-left shunts (RLS), and further evaluate the association between CVR and the occurrence of the white matter hyperintensities (WMHs).

METHODS

RLS was diagnosed based on a contrast enhancement transcranial Doppler (c-TCD) examination. The breath holding index (BHI), which represents CVR, was measured from the middle cerebral artery (MCA) using a TCD with the breath-holding method. WMHs was defined as clearly hyperintense areas in 3 T magnetic resonance imaging (MRI). All migraineurs underwent a standardized questionnaire for family and personal history and detailed migraine features.

RESULTS

Three hundred and ninety-seven migraineurs and 100 controls were included in our study. The BHI was significantly lower in migraineurs than controls (0.527 ± 0.709 vs. 0.674 ± 0.489, P = 0.016). Moreover, migraineurs with RLS had lower BHI than those without RLS (0.504 ± 0.671 vs. 0.674 ± 0.721, p = 0.024). Migraineurs with WMHs had lower BHI than those without (0.47 ± 0.71 vs. 0.75 ± 0.49, p = 0.035). The reduced BHI was an independent influencing factor for WMHs in our study (OR = 0.338; 95% CI = 0.142-0.806, p = 0.014).

CONCLUSION

Our results indicated that BHI was reduced in migraineurs, and the reduced BHI was associated with RLS. Moreover, the reduced CVR in migraineurs with RLS might be related to the occurrence of WMHs.

Profiling cerebrovascular function in migraine: A systematic review and meta-analysis

Previous studies have investigated whether migraine is a circulatory disorder, as migraineurs are at heightened risk of cerebrovascular disease. However, in most cases, systemic vascular function was evaluated, which may not reflect abnormalities in the cerebral circulation. Therefore, we aimed to determine whether cerebrovascular function differs between migraineurs and controls. A systematic literature search was conducted across three electronic databases to search for studies that compared cerebrovascular function in migraineurs to controls. Where applicable, meta-analyses were used to determine standardised mean differences (SMD) between migraineurs and controls. Seventy articles were identified, 40 of which contained quantitative data. Meta-analyses showed pulsatility index (PI) was higher (SMD = 0.23; 95%CI = 0.05 to 0.42, P = 0.01) and cerebrovascular responsiveness (CVR) to hypercapnia was lower (SMD=-0.34; 95%CI=-0.67 to -0.01, P = 0.04) in the posterior circulation of migraineurs, particularly those without aura. The meta-analyses also indicated that migraineurs have higher resting mean blood flow velocity in both anterior (SMD = 0.14; 95%CI = 0.05 to 0.23, P = 0.003) and posterior circulations (SMD = 0.20; 95%CI = 0.05 to 0.34, P = 0.007). Compared to healthy controls, migraineurs have altered cerebrovascular function, evidenced by elevated PI (representing arterial stiffness) and impaired CVR to hypercapnia (representing cerebral vasodilator function). Future studies should investigate whether improvement of cerebrovascular function is able to alleviate migraine.

Pathophysiological Bases of Comorbidity in Migraine

Despite that it is commonly accepted that migraine is a disorder of the nervous system with a prominent genetic basis, it is comorbid with a plethora of medical conditions. Several studies have found bidirectional comorbidity between migraine and different disorders including neurological, psychiatric, cardio- and cerebrovascular, gastrointestinal, metaboloendocrine, and immunological conditions. Each of these has its own genetic load and shares some common characteristics with migraine. The bidirectional mechanisms that are likely to underlie this extensive comorbidity between migraine and other diseases are manifold. Comorbid pathologies can induce and promote thalamocortical network dysexcitability, multi-organ transient or persistent pro-inflammatory state, and disproportionate energetic needs in a variable combination, which in turn may be causative mechanisms of the activation of an ample defensive system with includes the trigeminovascular system in conjunction with the neuroendocrine hypothalamic system. This strategy is designed to maintain brain homeostasis by regulating homeostatic needs, such as normal subcortico-cortical excitability, energy balance, osmoregulation, and emotional response. In this light, the treatment of migraine should always involves a multidisciplinary approach, aimed at identifying and, if necessary, eliminating possible risk and comorbidity factors.

The Role of Endothelial Dysfunction in the Pathophysiology and Cerebrovascular Effects of Migraine: A Narrative Review

Background and Purpose

Migraine is a complex neurovascular disorder whose triggers are not entirely understood. Endothelial dysfunction might play a role in migraine, and there have been numerous reports on endothelium dysfunction and migraine pathophysiology, but their reciprocal cause–effect relationship remains unclear. This review reports the current evidence on endothelium dysfunction, its link with migraine, and its possible consequences for cerebral hemodynamics.

Methods

We performed a systematic literature search of PubMed up to March 2020. We included 115 articles in a narrative review.

Results

Several studies have demonstrated that endothelium dysfunction may play an important role in migraine. Despite the lack of specific biomarkers, there is evidence of oxidative stress and inflammation—two of the primary causes of endothelial damage—in migraine. The main consequences of endothelial dysfunction are increased vascular tone, thrombosis, inflammation, and increased vascular permeability. As a consequence of oxidative stress, the activity of endothelin-1 is not counterbalanced by nitric oxide (NO), whose levels decrease to lead to vasoconstriction and a possible contribution to cortical spreading depression. NO is involved in pain perception via the cyclic guanosine monophosphate (cGMP) pathway and the induction of calcitonin gene-related peptide. Oxidative stress may induce a hypercoagulable state that mainly affects platelet function through different mechanisms. Endothelial dysfunction seems to be particularly pronounced in migraine with aura (MA). Endothelial dysfunction in migraine particularly involves intracranial vessels, since flow-mediated dilation cannot detect overt peripheral vascular dysfunction.

Conclusions

Endothelial dysfunction is a vascular risk marker. How it impacts migraine, and particularly MA, needs to be understood better by defining its possible role in increasing the stroke risk in migraine patients.

Cerebral vasomotor reactivity in migraine: effect of patent foramen ovale and aerogenic microembolism

OBJECTIVE

The first data on the effect of presence of patent foramen ovale (PFO) with high-volume right-to-left shunt (RLS) on cerebral vasomotor reactivity (CVMR) in migraineurs are herein presented. In addition, the immediate effect of air microbubbles on CVMR has been determined.

METHODS

Breath-holding index (BHI) and percent velocity decrease during hyperventilation (HPV) tests were performed before and after agitated saline injections in bilateral middle and posterior cerebral arteries (MCA and PCA) in 38 migraineurs (19 with aura) and 18 control subjects.

RESULTS

Presence of PFO correlated with a significant decrease of MCA BHI (1.43 ± 0.39 vs 1.04 ± 0.67, p = 0.032) and marginal reduction of PCA BHI (1.25 ± 0.46 vs. 1.01 ± 0.39, p = 0.090) in migraineurs. After agitated saline injection, PCA BHI significantly decreased from 1.03 to 0.78 (p = 0.007) in patients with PFO, from 1.15 to 0.91 (p = 0.014) in those without PFO, and from 1.01 to 0.76 (p = 0.023) in subjects with migraine and PFO. No significant MCA BHI difference was noted soon after bubble injection.

CONCLUSIONS

The presence of high grade RLS is associated with reduced vasodilatory CVMR in migraineurs. Further decrease of CVMR of PCA upon aerogenic microemboli passage may support the mechanism of 'facilitation with subclinical cerebral ischemia caused by microembolism', hypothesis explaining the onset of migraine.

ABBREVIATIONS

BHI: Breath-holding index; BHT: Breath Holding Test; CVMR: Cerebral vasomotor reactivity; EDV: End-diastolic velocity; HIT-6: Headache Impact Test; HPV: Hyperventilation; MCA: Middle cerebral artery; MIDAS: migraine disability Assessment score; PCA: Posterior cerebral artery; PFO: Patent foramen ovale; PI: Pulsatility index; PSV: Peak systolic velocity; RLS: Right-to-left shunt; TCD: Transcranial Doppler; Vmean: Mean velocity.

Cerebral vascular reactivity and the migraine-stroke relationship: A narrative review

Migraine, and especially migraine with aura, is associated with an increased risk of stroke and vascular events; however, the reasons for this association are unclear. Several studies evaluated cerebral autoregulation and vasomotor reactivity in patients with migraine compared with non-migraineurs, with conflicting results. Our narrative review aimed at summarizing their results to find the most reliable evidence in the field. Studies which used visual stimuli to evoke vascular responses consistently showed an increased vascular reactivity in migraineurs compared with non-migraineurs, while studies which used systemic stimuli such as hyper- or hypocapnia showed inconsistent results. Therefore, central neural mechanisms might be more important than peripheral vascular mechanisms in determining the cerebral vascular responses of patients with migraine. However, a large body of evidence supports the existence of peripheral vascular dysfunction in patients with migraine. Further studies are needed to explain the complex interactions between central neural and peripheral vascular mechanisms in determining migraine and its vascular risk. Migraine preventive treatments, and especially the most recent ones with a peripheral action, might provide important insights in this field.

Differential vasomotor responses to isocapnic hyperoxia: cerebral versus peripheral circulation

Isocapnic hyperoxia (IH) evokes cerebral and peripheral hypoperfusion via both disturbance of redox homeostasis and reduction in nitric oxide (NO) bioavailability. However, it is not clear whether the magnitude of the vasomotor responses depends on the vessel network exposed to IH. To test the hypothesis that the magnitude of IH-induced reduction in peripheral blood flow (BF) may differ from the hypoperfusion response observed in the cerebral vascular network under oxygen-enriched conditions, nine healthy men (25 ± 3 yr, mean ± SD) underwent 10 min of IH during either saline or vitamin C (3 g) infusion, separately. Femoral artery (FA), internal carotid artery (ICA), and vertebral artery (VA) BF (Doppler ultrasound), as well as arterial oxidant (8-isoprostane), antioxidant [ascorbic acid (AA)], and NO bioavailability (nitrite) markers were simultaneously measured. IH increased 8-isoprostane levels and reduced nitrite levels; these responses were followed by a reduction in both FA BF and ICA BF, whereas VA BF did not change. Absolute and relative reductions in FA BF were greater than IH-induced changes in ICA and VA perfusion. Vitamin C infusion increased arterial AA levels and abolished the IH-induced increase in 8-isoprostane levels and reduction in nitrite levels. Whereas ICA and VA BF did not change during the vitamin C-IH trial, FA perfusion increased and reached similar levels to those observed during normoxia with saline infusion. Therefore, the magnitude of IH-induced reduction in femoral blood flow is greater than that observed in the vessel network of the brain, which might involve the determinant contribution that NO has in the regulation of peripheral vascular perfusion.

Right-to-left shunts and hormonal therapy influence cerebral vasomotor reactivity in patients with migraine with aura

Patent Foramen Ovale and impaired cerebral hemodynamics were proposed among the pathophysiological mechanisms explaining the increased risk for stroke in patients with Migraine with Aura (MA). Our study aimed at comparing the vasomotor reactivity (VMR) of the anterior and the posterior cerebral circulation in patients with Migraine with Aura, in patients with acute vascular ischemic accidents, and in controls. We hypothesized that VMR in MA patients is preserved in the anterior circulation and reduced in the posterior circulation. We prospectively assessed with Transcranial Doppler the vasomotor reactivity to breath holding of the Middle and Posterior Cerebral Arteries (MCA, PCA) in MA patients, in acute vascular patients and healthy controls. We also evaluated the possible effect of clinical characteristics of MA (attack frequency, aura length or type, disease history), vascular factors and the presence of right-to-left shunt on VMR. Diverging from our hypothesis, MA patients displayed a higher breath-holding index (BHI) than controls in the MCA (1.84±0.47%/s vs 1.53±0.47%/s, p = .001) as well as in the PCA (1.87±0.65%/s vs 1.47±0.44%/s, p < .001). In MA patients, MCA BHI was higher in those with large right-to-left shunts (2.09±0.42 vs 1.79±0.47, p = .046) and lower in those taking estrogens (1.30±0.30%/s vs 1.9±0.45%/s, p = .009). We did not observe an effect of MA characteristics on BHI. The increased BHI in MA patients with large right-to-left shunts could be explained by the vasoactive effect in the cerebral circulation of substances bypassing the deactivating pulmonary filters or by a constitutional trait of the vascular system associating persistent right-to-left shunts and hyper-reactive hemodynamics. Our results discourage the hypothesis that altered hemodynamics contribute to increasing the stroke risk in all MA patients. However, estrogens can lower VMR, curtailing the hemodynamic resources of MA patients.

Aura and Stroke: relationship and what we have learnt from preclinical models

BACKGROUND

Population-based studies have highlighted a close relationship between migraine and stroke. Migraine, especially with aura, is a risk factor for both ischemic and hemorrhagic stroke. Interestingly, stroke risk is highest for migraineurs who are young and otherwise healthy.

MAIN BODY

Preclinical models have provided us with possible mechanisms to explain the increased vulnerability of migraineurs' brains towards ischemia and suggest a key role for enhanced cerebral excitability and increased incidence of microembolic events. Spreading depolarization (SD), a slowly propagating wave of neuronal depolarization, is the electrophysiologic event underlying migraine aura and a known headache trigger. Increased SD susceptibility has been demonstrated in migraine animal models, including transgenic mice carrying human mutations for the migraine-associated syndrome CADASIL and familial hemiplegic migraine (type 1 and 2). Upon experimentally induced SD, these mice develop aura-like neurological symptoms, akin to patients with the respective mutations. Migraine mutant mice also exhibit an increased frequency of ischemia-triggered SDs upon experimental stroke, associated with accelerated infarct growth and worse outcomes. The severe stroke phenotype can be explained by SD-related downstream events that exacerbate the metabolic mismatch, including pericyte contraction and neuroglial inflammation. Pharmacological suppression of the genetically enhanced SD susceptibility normalizes the stroke phenotype in familial hemiplegic migraine mutant mice. Recent epidemiologic and imaging studies suggest that these preclinical findings can be extrapolated to migraine patients. Migraine patients are at risk for particularly cardioembolic stroke. At the same time, studies suggest an increased incidence of coagulopathy, atrial fibrillation and patent foramen ovale among migraineurs, providing a possible path for microembolic induction of SD and, in rare instances, stroke in hyperexcitable brains. Indeed, recent imaging studies document an accelerated infarct progression with only little potentially salvageable brain tissue in acute stroke patients with a migraine history, suggesting an increased vulnerability towards cerebral ischemia.

CONCLUSION

Preclinical models suggest a key role for enhanced SD susceptibility and microembolization to explain both the occurrence of migraine attacks and the increased stroke risk in migraineurs. Therapeutic targeting of SD and microembolic events, or potential causes thereof, will be promising for treatment of aura and may also prevent ischemic infarction in vulnerable brains.

Paradoxical association between age and cerebrovascular reactivity in migraine: A cross-sectional study

BACKGROUND

Previous studies reported an increased risk of ischemic stroke in younger migraineurs. We aimed to investigate the association between age and cerebrovascular reactivity (CVR) to vasodilatory stimuli in cerebral arteries in patients with migraine and normal controls.

METHODS

In this cross-sectional study, we recruited 248 patients with migraine and 105 normal controls at Samsung Medical Center between October 2015 and July 2018. CVR was measured interictally by using the transcranial Doppler breath-holding test. For the arteries which showed a correlation between age and CVR, we conducted univariable and multivariable linear regression analysis to assess the independent effect of age on CVR. The path analysis was performed to assess mediating effects of the age of onset and disease duration on the age-CVR association.

RESULTS

Patients had reduced CVR in all tested arteries compared to normal controls. A correlation between age and CVR was present in the posterior cerebral artery (PCA) only in patients (Pearson's correlation coefficient = 0.160, p = 0.012). In patients, younger age was independently associated with lower CVR in the PCA (multivariable B = 0.003, 95% CI = 0.0002-0.005, p = 0.033 adjusted for sex, migraine subtype, and headache frequencies). The path analysis showed that the age of onset fully mediated the effect of age on PCA CVR, while longer disease duration negatively modified the effect of age of onset (p for interaction = 0.018).

CONCLUSIONS

In migraineurs, younger age was associated with CVR reduction in the PCA. Younger age of onset may be a hidden risk factor mediating the paradoxical association between age and CVR. This association might explain an increased risk of stroke in younger migraineurs.

Cerebrovascular reactivity as a determinant of deep white matter hyperintensities in migraine

OBJECTIVE

To evaluate the association between the cerebrovascular reactivity to carbon dioxide (CO₂-CVR) and the deep white matter hyperintensity (WMH) burden in patients with migraine.

METHODS

A total of 86 nonelderly patients with episodic migraine without vascular risk factors and 35 headache-free controls underwent 3T MRI. Deep WMHs were quantified with a segmentation method developed for nonelderly migraineurs. The interictal CO₂-CVR was measured with transcranial Doppler with the breath-holding method. The mean breath-holding index of the bilateral middle cerebral arteries (MCA-BHI) was square root transformed and analyzed with univariate and multivariate logistic regression models to determine its association with the highest tertiles of deep WMH burden (number and volume).

RESULTS

A low MCA-BHI was independently associated with the highest tertile of deep WMH number in patients with migraine (adjusted odds ratio [OR] 0.02, 95% confidence interval [CI] 0.0007-0.63, p = 0.026). In controls, the MCA-BHI was not associated with deep WMH number. Interaction analysis revealed that migraine modified the effect of MCA-BHI on deep WMH number (p for interaction = 0.029). The MCA-BHI was not associated with increased deep WMH volume in both patients and controls. Age was independently associated with deep WMH volume in patients (adjusted OR 1.07, 95% CI 1.004-1.15, p = 0.037).

CONCLUSIONS

In this study, we found a migraine-specific association between a reduced CVR to apnea and increased number of deep WMHs in healthy, nonelderly patients with migraine. A dysfunctional vascular response to apnea may predispose migraineurs to an increased risk of WMHs.

Human brain blood flow and metabolism during isocapnic hyperoxia: the role of reactive oxygen species

KEY POINTS

It is unknown whether excessive reactive oxygen species (ROS) production drives the isocapnic hyperoxia (IH)-induced decline in human cerebral blood flow (CBF) via reduced nitric oxide (NO) bioavailability and leads to disruption of the blood-brain barrier (BBB) or neural-parenchymal damage. Cerebral metabolic rate for oxygen (CMR O 2 ) and transcerebral exchanges of NO end-products, oxidants, antioxidants and neural-parenchymal damage markers were simultaneously quantified under IH with intravenous saline and ascorbic acid infusion. CBF and CMR O 2 were reduced during IH, responses that were followed by increased oxidative stress and reduced NO bioavailability when saline was infused. No indication of neural-parenchymal damage or disruption of the BBB was observed during IH. Antioxidant defences were increased during ascorbic acid infusion, while CBF, CMR O 2 , oxidant and NO bioavailability markers remained unchanged. ROS play a role in the regulation of CBF and metabolism during IH without evidence of BBB disruption or neural-parenchymal damage.

ABSTRACT

To test the hypothesis that isocapnic hyperoxia (IH) affects cerebral blood flow (CBF) and metabolism through exaggerated reactive oxygen species (ROS) production, reduced nitric oxide (NO) bioavailability, disturbances in the blood-brain barrier (BBB) and neural-parenchymal homeostasis, 10 men (24 ± 1 years) were exposed to a 10 min IH trial (100% O₂ ) while receiving intravenous saline and ascorbic acid (AA, 3 g) infusion. Internal carotid artery blood flow (ICABF), vertebral artery blood flow (VABF) and total CBF (tCBF, Doppler ultrasound) were determined. Arterial and right internal jugular venous blood was sampled to quantify the cerebral metabolic rate of oxygen (CMR O 2 ), transcerebral exchanges (TCE) of NO end-products (plasma nitrite), antioxidants (AA and AA plus dehydroascorbic acid (AA+DA)) and oxidant biomarkers (thiobarbituric acid-reactive substances (TBARS) and 8-isoprostane), and an index of BBB disruption and neuronal-parenchymal damage (neuron-specific enolase; NSE). IH reduced ICABF, tCBF and CMR O 2 , while VABF remained unchanged. Arterial 8-isoprostane and nitrite TCE increased, indicating that CBF decline was related to ROS production and reduced NO bioavailability. AA, AA+DA and NSE TCE did not change during IH. AA infusion did not change the resting haemodynamic and metabolic parameters but raised antioxidant defences, as indicated by increased AA/AA+DA concentrations. Negative AA+DA TCE, unchanged nitrite, reductions in arterial and venous 8-isoprostane, and TBARS TCE indicated that AA infusion effectively inhibited ROS production and preserved NO bioavailability. Similarly, AA infusion prevented IH-induced decline in regional and total CBF and re-established CMR O 2 . These findings indicate that ROS play a role in CBF regulation and metabolism during IH without evidence of BBB disruption or neural-parenchymal damage.

Interictal cerebral and systemic endothelial dysfunction in patients with migraine: a case-control study

BACKGROUND

Although systemic endothelial function is unimpaired in migraine, it is unknown whether cerebral endothelial function impairment exists in migraineurs.

MATERIALS AND METHODS

We conducted a prospective study to assess endothelial function in migraineurs (n=45) and healthy volunteers (n=44). Cerebral endothelial function was assessed by Breath Holding Index (BHI) on transcranial Doppler in bilateral middle cerebral artery (MCA at 30-60 mm), posterior cerebral artery (PCA at 60-80 mm) and basilar artery (BA at 80-120 mm) using bilateral monitoring probes fixed on headband. Brachial artery flow-mediated dilation (FMD) was used as measure of systemic endothelial function.

RESULTS

There was no difference in baseline mean velocities of MCA, PCA, BA among migraineurs and controls. Mean BHI was significantly lower in PCA (p<0.001) and BA (p<0.001) in patients with migraine with no difference in MCA (p=0.909, 0.450). Cerebral endothelial dysfunction (BHI<1.15) was present in 62.2% of migraineurs in the right PCA (p<0.001), 57.8% in left PCA (p<0.001) and 77.8% in BA (BHI <0.83, p<0.001). There was no difference in BHI among migraineurs without and with aura (n=15). Cerebral and systemic endothelial function had no correlation in migraineurs. Increasing BMI was identified as a predictor of impaired BHI in the BA in migraineurs (p=0.020). Age, sex, presence of aura, lateralisation of headache, headache frequency, time to last attack and impaired FMD were not associated with impaired PCA and BA BHI in migraineurs.

CONCLUSIONS

Migraineurs may have isolated cerebral endothelial dysfunction restricted to the posterior circulation in the absence of systemic endothelial dysfunction.

Is there a persistent dysfunction of neurovascular coupling in migraine?

Changes in cerebral blood flow are one of the main features of migraine attack and have inspired the vascular theory of migraine. This traditional view has been reshaped with recent experimental data, which gave rise to the neural theory of migraine. In this review, we speculate that there might be an important link between the two theories, that is, the dysfunction of neurovascular coupling.

Endothelial function in migraine with aura - a systematic review

BACKGROUND

An increased risk of ischemic stroke is repeatedly reported in young subjects with migraine with aura (MA). Such may be caused by changes in endothelial function. The present review evaluates current evidence on endothelial function in MA patients.

METHODS

A systematic search of electronic databases (Medline, Embase, Cochrane library) was performed, and a search in associated reference lists of identified studies was done.

RESULTS

In total, 27 studies met inclusion criteria for this review. Six studies assessed endothelial function by flow-mediated dilation; four reported no differences compared with healthy subjects, one study reported an increase and one study a decrease in migraineurs. Peripheral arterial tonometry was applied in one study where no changes were detected between groups. Likewise, applying venous occlusion plethysmography elicited comparable responses. Arterial function was investigated in six studies; increased augmentation index and decreased arterial distensibility were reported in migraineurs, whereas findings regarding pulse wave velocity were dissimilar. However, when investigating levels of endothelial progenitor cells, two studies reported reduced levels in migraineurs, and several studies on endothelial markers in the areas of inflammation, oxidative stress, and coagulation found increased endothelial activation in migraineurs, particularly in MA. One study, assessing cerebral endothelial function using transcranial Doppler sonography, reported lower cerebrovascular reactivity to L-arginine in the posterior cerebral arteries in migraineurs.

CONCLUSION

Endothelial dysfunction appears not to be of importance in MA patients. However, the studies were few with a wide variety of techniques applied in small groups of patients. Endothelial biomarkers were increased in patients indicating a possible subtle change in the endothelium. Further investigations on larger groups of patients combining testing of endothelial dysfunction as well as biomarkers are warranted to identify whether or not endothelial changes may play a role in the increased risk of stroke in young MA patients.

Markers of endothelial function in migraine patients: Results from a bi-center prospective study

Background

Numerous studies suggest an increased vascular risk in patients with migraine, in particular in those with aura. A possible link between both conditions might be a dysfunction of the vascular endothelium. This observational study analyzed the endothelial markers angiopoietin-1, angiopoietin-2, Tie-2, sFlt-1 and NT-proBNP for the first time in migraineurs, patients with other primary headache disorders and healthy controls.

Methods

Patients with episodic migraine with and without aura, episodic cluster headache, tension-type headache and healthy controls were included. Blood samples were obtained during migraine attacks and headache-free periods in migraineurs, in and out of bout in cluster headache and during headache-free periods in tension-type headache and healthy individuals to analyze markers of endothelial function.

Results

No significant difference in endothelial markers between migraine, other headache disorders and healthy controls was detected. There was no significant difference between migraine attacks and headache-free intervals. Additionally, no distinction could be found between migraine with and without aura.

Discussion

The endothelial markers analyzed do not display a characteristic pattern in different headache disorders especially migraine compared to healthy controls. The novel findings of our study indicate that factors other than endothelial dysfunction seem to be responsible for the at least statistical association of migraine with vascular disease.

Diffusion-weighted lesions in acute ischaemic stroke patients with migraine

OBJECTIVES

There is increasing knowledge about an association between migraine and ischaemic stroke. Cortical spreading depression (CSD) is the probable biological substrate of migrainous aura. To investigate the influence of CSD on the apparent stroke - migraine association, we hypothesized that magnetic resonance (MR) diffusion weighted images of acute ischaemic stroke patients would reveal an association between small cortical infarctions and migraine.

METHODS

We included all patients admitted to the Bergen stroke unit between 2006 and 2012 with verified acute ischaemic stroke by MR imaging. Patients were grouped in a migraine and a no-migraine group. Baseline data and clinical characteristics were analysed between the groups. Imaging data were analysed with respect to infarct location and size. Multivariate analyses were performed to adjust for confounders and provide risk estimates for observed associations.

RESULTS

A total of 1703 subjects were enrolled, 787 subjects were excluded due to uncertain or unobtainable migraine diagnosis, leaving 196 and 720 subjects in the migraine and no-migraine group, respectively. The migraine group was younger and included a higher proportion of females. There were more infarctions due to cardio-embolism (P=0.015) and fewer due to small vessel disease (P=0.018) in the migraine group. A higher rate of patients in the migraine group presented symptoms from the posterior circulation (P=0.008). Migraine was associated with cortical infarctions (OR 1.8 CI: 1.3-2.5, P=0.001). Migraine was also associated with small infarctions (OR 1.9 CI: 1.04-3.5, P=0.038).

CONCLUSIONS

Migraine was associated with small cortical infarctions. This association may be due to cortical spreading depression.

Study of neurovascular coupling during cold pressor test in patients with migraine

BACKGROUND

Altered neurovascular coupling in migraineurs could be a consequence of impaired function of modulatory brainstem nuclei. The cold pressor test (CPT) should activate brainstem structures. We measured visually evoked cerebral blood flow velocity response (VEFR) to CPT in migraine.

METHODS

Twenty-three healthy volunteers and 29 migraineurs participated in the study. We measured arterial blood pressure, end-tidal CO2, heart rate and cerebral blood flow velocity in posterior and middle cerebral artery using transcranial Doppler. VEFR was calculated as cerebrovascular reactivity to photic stimulation before, during and after CPT.

RESULTS

In healthy individuals, there was a significant decrease in peak systolic VEFR from CPT phase to recovery phase (p < 0.05). There was an increase in mean VEFR from basal to CPT phase and a decrease from CPT to recovery phase, both significant (p < 0.05). End-diastolic VEFR increased from basal to CPT phase and decreased in recovery phase below the basal phase values, all changes significant (p < 0.05). In migraine, no statistically significant changes in peak systolic, mean or end-diastolic VEFRs were observed between phases (p > 0.05). The differences in phases in mean and end-diastolic VEFRs between the basal phase and the CPT phase and between the CPT phase and the recovery phase were significantly higher in healthy individuals (p < 0.05).

CONCLUSIONS

The absence of the effect of CPT on VEFR in migraine is likely to be a consequence of impaired subcortical modulation of neurovascular coupling.

Migraine and stroke: in search of shared mechanisms

BACKGROUND

Migraine, particularly with aura, increases the risk for ischemic stroke, at least in a subset of patients. The underlying mechanisms are poorly understood and probably multifactorial.

METHODS

We carried out an extended literature review of experimental and clinical evidence supporting the association between migraine and ischemic stroke to identify potential mechanisms that can explain the association.

RESULTS

Observational, imaging and genetic evidence support a link between migraine and ischemic stroke. Based on clinical and experimental data, we propose mechanistic hypotheses to explain the link, such as microembolic triggers of migraine and enhanced sensitivity to ischemic injury in migraineurs.

DISCUSSION

We discuss the possible practical implications of clinical and experimental data, such as aggressive risk factor screening and management, stroke prophylaxis and specific acute stroke management in migraineurs. However, evidence from prospective clinical trials is required before modifying the practice in this patient population.

Cerebral endothelial function determined by cerebrovascular reactivity to L-arginine

Endothelium forms the inner cellular lining of blood vessels and plays an important role in many physiological functions including the control of vasomotor tone. Cerebral endothelium is probably one of the most specific types but until recently it was impossible to determine its function. In this review, the role of cerebrovascular reactivity to L-arginine (CVR-L-Arg) for assessment of cerebral endothelial function is discussed. L-Arginine induces vasodilatation through enhanced production of nitric oxide (NO) in the cerebral endothelium. Transcranial Doppler sonography is used for evaluation of cerebral blood flow changes. The method is noninvasive, inexpensive, and enables reproducible measurements. CVR-L-Arg has been compared to flow-mediated dilatation as a gold standard for systemic endothelial function and intima-media thickness as a marker for morphological changes. However, it seems to show specific cerebral endothelial function. So far CVR-L-Arg has been used to study cerebral endothelial function in many pathological conditions such as stroke, migraine, etc. In addition CVR-L-Arg has also proven its usefulness in order to show potential improvement after pharmacological interventions. In conclusion CVR-L-Arg is a promising noninvasive research method that could provide means for evaluation of cerebral endothelial function in physiological and pathological conditions.

Migraine-related ischemic stroke?

INTRODUCTION

Migraine, especially migraine with aura, has been described to be associated with an increased risk for ischemic stroke. An increased incidence of silent lesions in the posterior circulation has also been described.

METHOD

Six cases with migraine and stroke in close relation over time were retrospectively reviewed.

RESULTS

All patients had previously known MA or MO and suffered from a stroke within the first 24-hour period after an acute migraine attack. None of the patients fulfilled the IHS criteria for migrainous infarction. Four out of these six patients had a patent foramen ovale (PFO) or an atrial septal defect (ASD).

DISCUSSION

None of these cases can be categorized as migrainous infarctions according to IHS. However, the migraine attack might have been involved in the mechanisms for the development of the infarctions.

Decreased reactivity of skin microcirculation in response to L-arginine in later-onset type 1 diabetes

OBJECTIVE

The aim of our study was to evaluate the vasodilatory effect of l-arginine infusion on the skin microcirculation and to assess the relationship between this effect and the presence of microangiopathy in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Capillaroscopy was performed before and after l-arginine infusion in 48 diabetic patients (26 women and 22 men; age, 39.8 ± 6.3 years) and 24 volunteers free of any chronic disease (13 women and 11 men; age, 38.0 ± 6.7 years). The skin microcirculation reactivity, as expressed by the percentage of area covered by capillaries (coverage) and the distance between capillaries (distance), and the relationship between microcirculation reactivity and the presence of microangiopathic complications were assessed.

RESULTS

The distance before l-arginine infusion was significantly lower in patients than in controls (221 [153-311] vs. 240 [185-356] µm; P = 0.02) and did not differ after l-arginine infusion (223.5 [127-318] vs. 242.5 [181-341] µm; P = 0.27). The difference between the coverage values obtained before and after l-arginine infusion (Δcoverage) was significantly different from zero in the control group but not in the diabetes group. Patients with later onset of diabetes were characterized by decreased skin microcirculation reactivity when compared with patients with earlier onset of diabetes (-1.18 [-5.07 to 11.60] vs. 1.36 [-6.00 to 8.06]; P = 0.02) despite the higher prevalence of retinopathy in patients with earlier onset of diabetes (64% vs. 26%; P = 0.02).

CONCLUSIONS

Skin microvascular reactivity is impaired in patients with later onset of type 1 diabetes. Capillaroscopy with l-arginine infusion is useful for the identification of skin microangiopathy in type 1 diabetes.

Structural and functional neuroimaging in migraine: insights from 3 decades of research

Modern imaging methods provide unprecedented insights into brain structure, perfusion, metabolism, and neurochemistry, both during and between migraine attacks. Neuroimaging investigations conducted in recent decades bring us closer to uncovering migraine as a multifaceted, primarily central nervous system disorder. Three main categories of structural and functional brain changes are described in this review, corresponding to the migrainous aura, ictal headache, and interictal states. These changes greatly advance our understanding of multiple pathophysiologic underpinnings of migraine, from central "migraine generating" loci, to cortical spreading depression, intimate mechanisms underlying activation of neuronal pain pathways in vulnerable patients, central sensitization, and chronification. Structural imaging begins to explain the complex connections between migraine and cerebral vascular events, white matter lesions, grey matter density alterations, iron deposition, and microstructural brain damage. Selected structural and functional alterations of brain structures, as identified with imaging methods, may represent the foundation of new diagnostic strategies and serve as markers of therapeutic efficacy.

Peripheral endothelial function and arterial stiffness in women with migraine with aura: a case-control study

BACKGROUND

Vascular dysfunction may be involved in migraine pathophysiology and contribute to the increased risk of ischemic stroke in migraine, particularly in women with migraine with aura (MA). However, data on endothelial function in MA are controversial. Here, we investigated whether systemic endothelial function and arterial stiffness are altered in women with MA, using a novel peripheral arterial tonometry device for the first time.

METHODS

Twenty-nine female MA patients without comorbidities and 30 healthy women were included, and carotid intima-media thickness was assessed by a standardized procedure. Endothelial function was assessed using peripheral arterial tonometry. Reactive hyperaemic response of digital pulse amplitude was measured following 5 minutes of forearm occlusion of the brachial artery. Arterial stiffness was assessed by fingertip tonometry derived and heart-rate-adjusted augmentation index.

RESULTS

No differences were found in peripheral arterial tonometry ratio (2.3 ± 0.6 vs 2.2 ± 0.8; p = 0.58) and left carotid intima-media thickness (in µm: 484 ± 119 vs 508 ± 60; p = 0.37). Women with MA had higher heart-rate-averaged augmentation index [median (interquartile range, IQR) of 5 (IQR 0.5 to 18) vs -5 (IQR -16.8 to 8.3), p = 0.005] and heart-rate-adjusted augmentation index [1 (IQR -6 to 12.5) vs -8 (IQR -20.3 to 2.5), p = 0.008] than healthy controls.

CONCLUSION

Peripheral endothelial function is not impaired in women with MA, but they have greater arterial stiffness. This may contribute to the increased stroke risk in women with MA.

Associations between cerebral and systemic endothelial function in migraine patients: a post-hoc study

Background

There is a growing interest in the role of the endothelium in migraine. Recently, our group showed differences in endothelial function between the anterior and posterior cerebral circulation in healthy subjects, reduced vasodilatatory capacity of the posterior cerebral circulation and unimpaired systemic endothelial function in migraine patients without comorbidities. However, the relationship between cerebral and systemic endothelial function and the anterior and posterior cerebral endothelial function in migraine patients is still not clear.

Methods

We compared cerebral and systemic endothelial function through post-hoc linear regression analysis of cerebrovascular reactivity (CVR) to L-arginine between the middle cerebral artery (MCA) and flow-mediated vasodilatation (FMD) of the right brachial artery and the posterior cerebral artery (PCA) and FMD in migraine patients without comorbidities and in healthy subjects. The anterior and posterior cerebral endothelial function was also compared using post-hoc linear regression analysis between CVR to L-arginine in the MCA and the PCA.

Results

No significant correlation was found between CVR to L-arginine in the MCA and FMD and in the PCA and FMD in migraine patients with aura (p = 0.880 vs. p = 0.682), without aura (p = 0.153 vs. p = 0.179) and in healthy subjects (p = 0.869 vs. p = 0.662). On the other hand, we found a significant correlation between CVR to L-arginine in the MCA and PCA in migraine patients with aura (p = 0.004), without aura (p = 0.001) and in healthy subjects (p = 0.002). Detailed analysis of the linear regression between all migraine patients and healthy subjects did not show any difference in the regression coefficient (slope) (p = 0.382). However, a significant difference in curve elevation (intercept) was found (p = 0.002).

Conclusions

Our study suggests that the endothelial function in the cerebral and systemic circulation might be different in migraine patients without comorbidities, while that of the anterior and posterior cerebral circulation might be coupled. These results could improve understanding of endothelial function in migraine patients without comorbidities.