Role of cortical spreading depression in the pathophysiology of migraine

Identification of Polymorphisms in EAAT1 Glutamate Transporter Gene SLC1A3 Associated with Reduced Migraine Risk

Dysfunction in ion channels or processes involved in maintaining ionic homeostasis is thought to lower the threshold for cortical spreading depression (CSD), and plays a role in susceptibility to associated neurological disorders, including pathogenesis of a migraine. Rare pathogenic variants in specific ion channels have been implicated in monogenic migraine subtypes. In this study, we further examined the channelopathic nature of a migraine through the analysis of common genetic variants in three selected ion channel or transporter genes: SLC4A4, SLC1A3, and CHRNA4. Using the Agena MassARRAY platform, 28 single-nucleotide polymorphisms (SNPs) across the three candidate genes were genotyped in a case-control cohort comprised of 182 migraine cases and 179 matched controls. Initial results identified significant associations between migraine and rs3776578 (p = 0.04) and rs16903247 (p = 0.05) genotypes within the SLC1A3 gene, which encodes the EAAT1 glutamate transporter. These SNPs were subsequently genotyped in an independent cohort of 258 migraine cases and 290 controls using a high-resolution melt assay, and association testing supported the replication of initial findings-rs3776578 (p = 0.0041) and rs16903247 (p = 0.0127). The polymorphisms are in linkage disequilibrium and localise within a putative intronic enhancer region of SLC1A3. The minor alleles of both SNPs show a protective effect on migraine risk, which may be conferred via influencing the expression of SLC1A3.

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.

Migraine and the Gender Divide

Migraine is a global neurologic disease that is highly prevalent, especially in women. Studies have observed a predisposition for the development of migraine in women, although the mechanisms involved have yet to be fully elucidated. This review aimed to summarize the recent evidence regarding the epidemiology, pathophysiology, and treatment of migraine and highlight key sex differences. We also identify gaps in care for both women and men living with migraine and discuss the presence of migraine-related stigma and how this may impact the efficacy of clinical care.

The relationship between major depression and migraine: A bidirectional two-sample Mendelian randomization study

Background

Previous epidemiological and other studies have shown an association between major depressive disorder (MDD) and migraine. However, the causal relationship between them remains unclear. Therefore, this study aimed to investigate the causal relationship between MDD and migraine using a bidirectional, two-sample Mendelian randomization (MR) approach.

Methods

Data on MDD and migraine, including subtypes with aura migraine (MA) and without aura migraine (MO), were gathered from a publicly available genome-wide association study (GWAS). Single nucleotide polymorphisms (SNPs) utilized as instrumental variables (IVs) were then screened by adjusting the intensity of the connection and removing linkage disequilibrium. To explore causal effects, inverse variance weighting (IVW) was used as the primary analysis method, with weighted median, MR-Egger, simple mode, and weighted mode used as supplementary analytic methods. Furthermore, heterogeneity and pleiotropy tests were carried out. Cochran's Q-test with IVW and MR-Egger was used to assess heterogeneity. Pleiotropy testing was carried out using the MR-Egger intercept and MR-PRESSO analysis methods. A leave-one-out analysis was also used to evaluate the stability of the findings. Finally, we used migraine (MA and MO) levels to deduce reverse causality with MDD risk.

Results

Random effects IVW results were (MDD-Migraine: odds ratio (OR), 1.606, 95% confidence interval (CI), 1.324-1.949, p = 1.52E-06; MDD-MA: OR, 1.400, 95%CI, 1.067-1.8378, p = 0.015; MDD-MO: OR, 1.814, 95%CI, 1.277-2.578, p = 0.0008), indicating a causal relationship between MDD levels and increased risk of migraine (including MA and MO). In the inverse MR analysis, the findings were all negative, while in sensitivity analyses, the results were robust except for the study of MA with MDD.

Conclusion

Our study confirms a causal relationship between MDD levels and increased risk of migraine, MA, and MO. There was little evidence in the reverse MR analysis to suggest a causal genetic relationship between migraine (MA and MO) and MDD risk levels.

Review and Hypothesis: A Potential Common Link Between Glial Cells, Calcium Changes, Modulation of Synaptic Transmission, Spreading Depression, Migraine, and Epilepsy-H. Front Cell Neurosci 2021;15:693095. [PMID: 34539347 PMCID: PMC8446203 DOI: 10.3389/fncel.2021.693095]

There is significant evidence to support the notion that glial cells can modulate the strength of synaptic connections between nerve cells, and it has further been suggested that alterations in intracellular calcium are likely to play a key role in this process. However, the molecular mechanism(s) by which glial cells modulate neuronal signaling remains contentiously debated. Recent experiments have suggested that alterations in extracellular H+ efflux initiated by extracellular ATP may play a key role in the modulation of synaptic strength by radial glial cells in the retina and astrocytes throughout the brain. ATP-elicited alterations in H+ flux from radial glial cells were first detected from Müller cells enzymatically dissociated from the retina of tiger salamander using self-referencing H+-selective microelectrodes. The ATP-elicited alteration in H+ efflux was further found to be highly evolutionarily conserved, extending to Müller cells isolated from species as diverse as lamprey, skate, rat, mouse, monkey and human. More recently, self-referencing H+-selective electrodes have been used to detect ATP-elicited alterations in H+ efflux around individual mammalian astrocytes from the cortex and hippocampus. Tied to increases in intracellular calcium, these ATP-induced extracellular acidifications are well-positioned to be key mediators of synaptic modulation. In this article, we examine the evidence supporting H+ as a key modulator of neurotransmission, review data showing that extracellular ATP elicits an increase in H+ efflux from glial cells, and describe the potential signal transduction pathways involved in glial cell-mediated H+ efflux. We then examine the potential role that extracellular H+ released by glia might play in regulating synaptic transmission within the vertebrate retina, and then expand the focus to discuss potential roles in spreading depression, migraine, epilepsy, and alterations in brain rhythms, and suggest that alterations in extracellular H+ may be a unifying feature linking these disparate phenomena.

Complement Component C3 Loss leads to Locomotor Deficits and Altered Cerebellar Internal Granule Cell In Vitro Synaptic Protein Expression in C57BL/6 Mice

Complement component 3 (C3) expression is increased in the cerebellum of aging mice that demonstrate locomotor impairments and increased excitatory synapse density. However, C3 regulation of locomotion, as well as C3 roles in excitatory synapse function, remains poorly understood. Here, we demonstrate that constitutive loss of C3 function in mice evokes a locomotor phenotype characterized by decreased speed, increased active state locomotor probability, and gait ataxia. C3 loss does not alter metabolism or body mass composition. No evidence of significant muscle weakness or degenerative arthritis was found in C3 knockout mice to explain decreased gait speeds. In an enriched primary cerebellar granule cell culture model, loss of C3 protein results in increased excitatory synaptic density and increased response to KCl depolarization. Our analysis of excitatory synaptic density in the cerebellar internal granule cell and molecular layers did not demonstrate increased synaptic density in vivo, suggesting the presence of compensatory mechanisms regulating synaptic development. Functional deficits in C3 knockout mice are therefore more likely to result from altered synaptic function and/or connectivity than gross synaptic deficits. Our data demonstrate a novel role for complement proteins in cerebellar regulation of locomotor output and control.

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.

Migraine with Brainstem Aura Accompanied by Disorders of Consciousness

Migraine with brainstem aura (MBA) accompanied by disorders of consciousness (DOC) is a rare subtype of migraine. The pathophysiology of MBA with DOC has not been elucidated yet. Some patients have a family history of migraine, and women are more affected than men. The aura symptoms are diverse; however, when MBA is combined with DOC, the clinical manifestations are more complicated. Coma is the most common clinical manifestation. The overall duration of the patient’s DOC is short and can often return to normal within half an hour. Headache often occurs after regaining consciousness and can also occur at the same time as DOC. The most common headache is located at the occipital region. Although DOC is reversible, considering the current small number of cases, we still need to improve our understanding of the disease to avoid misdiagnosis. The MBA patient’s electroencephalogram and cerebral blood flow perfusion may have transient changes and may return to normal in the interictal period or after the DOC. Although triptans have traditionally been contraindicated in MBA under drug instructions, the evidence of basilar artery constriction, as postulated in MBA, is lacking. Lasmiditan is currently the first and only 5-HT 1F receptor agonist approved by the Food and Drug Administration. The calcitonin gene-related peptide receptor antagonists and monoclonal antibody therapies may be the most promising for future consideration. Here, the pathophysiology, clinical manifestations, diagnostic tools, and treatment progress for MBA with DOC are reviewed.

Lateralization value of peri-ictal headache in drug-resistant focal epilepsy

OBJECTIVE

To examine the lateralizing value of unilateral peri-ictal and interictal headaches in patients with drug-resistant focal epilepsy (DRFE).

METHODS

Four-hundred consecutive patients undergoing presurgical evaluation for DRFE were interviewed. Patients with headache were broadly divided into two groups: peri-ictal and interictal headache. The lateralizing value of unilateral headache was compared in each group between three diagnoses: temporal lobe epilepsy (TLE), extratemporal lobe epilepsy (ETLE), and temporal-plus epilepsy (TEMP+ epilepsy).

RESULTS

Out of 400 patients, 169 (42.25%) had headaches. Peri-ictal headaches were experienced in 106 patients (26.5%) and interictal headaches were experienced in 63 (15.75%). In the peri-ictal group, unilateral headaches were present in 48 out of 60 patients (80%) with TLE; they were ipsilateral to the seizure focus in 45 out of 48 patients (93.75%). Unilateral headaches in patients with ETLE were present in 20 out of 31 patients (64.5%) and were ipsilateral to the seizure focus in 14 out of 20 patients (70%). In patients with TEMP + epilepsy, unilateral peri-ictal headaches were present in 9 out of 15 patients (60%); they were ipsilateral to the seizure focus in all 9 patients (100%). In the interictal headache group, unilateral headaches were ipsilateral the seizure focus in 9 out of 10 patients (90%) with TLE and 5 out of 6 patients (83.3%) with ETLE. None of the TEMP + epilepsy patients had a unilateral interictal headache.

CONCLUSION

Headache is a frequently encountered symptom in patients with DRFE. When occurring in a unilateral fashion, it has a high lateralizing value in temporal and extratemporal lobe epilepsies. This has been demonstrated to be true for both peri-ictal and interictal headaches. In the vast majority of patients with DRFE, unilateral headache occurs ipsilateral to the seizure focus.

The role of the immune system and the biomarker CD3 + CD4 + CD45RA-CD62L- in the pathophysiology of migraine

The role of the immune system as an integral component of the inflammatory response in the pathophysiology of migraine remains unclear. The aim of this study was to evaluate the differences in immune system parameters (acquired immunity parameters) in patients with episodic migraine (EM) and in healthy controls. In EM patients, we aimed to determine whether the changes found in peripheral blood parameters were related to migraine severity according to the standardised MIDAS and HIT-6 tests. Forty-nine patients with EM and 50 healthy controls were included in this study. The authors compared different lymphocyte parameters obtained by multicolor flow cytometry in the EM and control groups by performing statistical tests. The relationship between the changes in peripheral blood parameters and migraine severity in EM patients was investigated using correlation and regression analysis. EM patients showed higher values than healthy controls, especially in nine parameters: relative count of lymphocytes, relative and absolute counts of CD3 T cells, relative and absolute counts of CD8 suppressor cytotoxic T cells, relative and absolute counts of CD4 + TEMRA (terminally differentiated helper T lymphocytes), absolute count of CD8 naïve T cells, and absolute count of CD19 switched memory B cells. Among the lymphocyte parameters, CD4 + TEM (effector memory helper T lymphocytes) and CD8 + TEMRA (terminally differentiated cytotoxic T lymphocytes) were statistically significantly associated with HIT-6. Patients with a CD4 + TEM value below 15 had a high probability (90%) that the HIT-6 value would be higher than 60. The results of this study show that EM patients have changes in immune system parameters measured in the peripheral blood. Changes in the abundance of CD4 + TEM could be used as a biomarker for disease severity.

Endothelial and Autonomic Functions in Patients with Migraine

OBJECTIVE

It has been shown that patients with migraine have endothelial dysfunction. Migraine patients with aura, especially, have more clinical manifestations of autonomic nervous system dysfunction. We aimed to evaluate the endothelial and autonomic functions in migraine patients during both migraine headache attack and headache-free periods.

DESIGN

This was a cross-sectional, randomized study.

SUBJECTS AND METHODS

A total of 130 participants (67 male and 63 female patients, minimum age = 19 years, maximum age = 71 years, mean age = 38.8 ± 12.2 years) were enrolled into the study. For the statistical evaluation of data, we classified the participants of the study as follows: group 1: headache (+) aura (+); group 2: headache (+) aura (-); group 3: headache (-) aura (+); group 4: headache (-) aura (-). Noninvasive evaluation of endothelial function was performed by flow-mediated dilation (FMD) and pulse wave analysis methods. Heart rate variability measurements were used for noninvasive evaluation of autonomic functions.

RESULTS

Group 1 had a higher FMD ratio than the control group, group 3, or group 4 (P < 0.001, P < 0.001, and P = 0.003, respectively). Group 4 had lower FMD ratio levels than the other migraine groups and or the control group (P < 0.001). Group 3 had the highest high-frequency (HF) power levels among all migraine groups (P < 0.001). Group 2 had higher low-frequency/HF ratio values than other migraineurs (P < 0.001).

CONCLUSIONS

We concluded that endothelial dysfunction and headache are closely related. Additionally, higher parasympathetic tonus might be associated with the presence of aura.

Merits and Limitations of Studying Neuronal Depolarization-Dependent Processes Using Elevated External Potassium

Elevated extracellular potassium chloride is widely used to achieve membrane depolarization of cultured neurons. This technique has illuminated mechanisms of calcium influx through L-type voltage sensitive calcium channels, activity-regulated signaling, downstream transcriptional events, and many other intracellular responses to depolarization. However, there is enormous variability in these treatments, including durations from seconds to days and concentrations from 3mM to 150 mM KCl. Differential effects of these variable protocols on neuronal activity and transcriptional programs are underexplored. Furthermore, potassium chloride treatments in vitro are criticized for being poor representatives of in vivo phenomena and are questioned for their effects on cell viability. In this review, we discuss the intracellular consequences of elevated extracellular potassium chloride treatment in vitro, the variability of such treatments in the literature, the strengths and limitations of this tool, and relevance of these studies to brain functions and dysfunctions.

Genetic Screening of Plasticity Regulating Nogo-Type Signaling Genes in Migraine

Migraine is the sixth most prevalent disease in the world and a substantial number of experiments have been conducted to analyze potential differences between the migraine brain and the healthy brain. Results from these investigations point to the possibility that development and aggravation of migraine may include grey matter plasticity. Nogo-type signaling is a potent plasticity regulating system in the CNS and consists of ligands, receptors, co-receptors and modulators with a dynamic age- and activity-related expression in cortical and subcortical regions. Here we investigated a potential link between migraine and five key Nogo-type signaling genes: RTN4, OMGP, MAG, RTN4R and LINGO1, by screening 15 single nucleotide polymorphisms (SNPs) within these genes. In a large Swedish migraine cohort (749 migraine patients and 4032 controls), using a logistic regression with sex as covariate, we found that there was no such association. In addition, a haplotype analysis was performed which revealed three haplotype blocks. These blocks had no significant association with migraine. However, to robustly conclude that Nogo-type genotypes signaling do not influence the prevalence of migraine, further studies are encouraged.

Upregulation of IL-1 Receptor Antagonist in a Mouse Model of Migraine

Migraine is a disorder characterized by attacks of monolateral headaches, often accompanied by nausea, vomiting, and photophobia. Around 30% of patients also report aura symptoms. The cause of the aura is believed to be related to the cortical spreading depression (CSD), a wave of neuronal and glial depolarization originating in the occipital cortex, followed by temporary neuronal silencing. During a migraine attack, increased expression of inflammatory mediators, along with a decrease in the expression of anti-inflammatory genes, have been observed. The aim of this study was to evaluate the expression of inflammatory genes, in particular that of IL-1 receptor antagonist (IL-1RN), following CSD in a mouse model of familial hemiplegic migraine type 1 (FHM-1). We show here that the expression of IL-1RN was upregulated after the CSD, suggesting a possible attempt to modulate the inflammatory response. This study allows researchers to better understand the development of the disease and aids in the search for new therapeutic strategies in migraine.

Pharmacogenetic considerations for migraine therapies

INTRODUCTION

Migraine is a common neurological disorder with a complex pathophysiology. It has been estimated that incidence between adults of current headache disorder is about 50%. Different studies show that this condition has an important and complex genetic component in response to drug therapy. Areas covered: This review shows and summarizes the importance of the polymorphisms associated with the major antimigraine drug metabolizing enzymes. The research of bibliographic databases has involved only published peer-reviewed articles from indexed journals. Expert opinion: Pharmacogenetics is based on the identification of polymorphism and promises personalized therapy with efficacy and reduction of adverse events. The association between genotype and an altered metabolizer status could guide clinical decision to evade concomitant treatments and adverse events. The introduction of routine genetic testing could help to choose the efficacy drug on the individual and genetic profile.

Behavioral study of a rat model of migraine induced by CGRP

Migraine is a debilitating disorder characterized by recurrent headache arising from neurovascular dysfunction. Despite recent progress in migraine research, the exact mechanisms underpinning migraine are poorly understood. Furthermore, it is difficult to develop an animal model of migraine that resembles all symptoms of patients. In this study, we established a novel animal model of migraine induced by epidural injection of calcitonin gene-related peptide (CGRP), and examined climbing hutch behavior, facial-grooming behavior, body-grooming behavior, freezing behavior, resting behavior, and ipsilateral hindpaw facial grooming behavior of rats following CGRP injection. CGRP significantly reduced climbing hutch behavior, and face-grooming behavior, and increased immobile behavior. We also found that the P15 and P85 percentile range of behavioral data exhibited a high positive rate (83.3%) for establishing the model with less false positive rate. Our results verified that the rat model of migraine induced by CGRP featured many behaviors of migraine patients demonstrated during migraine attacks. Our findings suggest that this new model can be a useful tool for understanding the pathophysiology of migraine and studying novel therapeutic strategies for the treatment of migraine.

Do the accelerating actions of tianeptine and l-arginine on cortical spreading depression interact? An electrophysiological analysis in young and adult rats

In the rat, we previously demonstrated that serotonin-enhancing drugs impair cortical spreading depression (CSD) and that l-arginine (arginine) treatment enhances CSD. Here, we investigated the interaction between topical application of the serotonin uptake enhancer tianeptine and systemic arginine administration on CSD. From postnatal day 7-28, female Wistar rats (n=40) received by gavage 300mg/Kg/day arginine (n=20) or water (n=20). Half of the arginine- or water-treated rats underwent CSD recording at 30-40days of age (young), while the other half was recorded at 90-120days (adult). Following baseline recording (four episodes of CSD), we applied tianeptine solution (10mg/ml) to a rectangular portion of the intact dura mater for 10-min and then elicited CSD. This procedure was repeated three times. Compared to baseline values, CSD velocities and amplitudes following tianeptine application increased, and CSD duration decreased significantly (p<0.05) in both young and adult rats, regardless of treatment group. CSD acceleration caused by systemic treatment with arginine is in agreement with previous findings. Topical cortical application of tianeptine replicated the effect of systemic application, suggesting a cortically based mechanism for tianeptine's action. However, the absence of interaction between arginine and tianeptine treatments suggests that they probably act through separate mechanisms.

Migraine Modulation and Debut after Percutaneous Atrial Septal Defect Closure: A Review

INTRODUCTION

Change in migraine headache (MH)-preexisting MH change or development of de novo MH-are known potential complications following percutaneous closure of atrial septal defect (ASD), but consensus on a causal trigger remains elusive.

OBJECTIVES

To expose potential MH triggers linked, mainly by timing and occurrence, to the emergence of de novo MH or change in preexisting MH subsequent to percutaneous ASD closure (pASDC).

METHODS

The literature was systematically searched for studies available in English reporting MH status after pASDC published between January 1, 1990 and November 15, 2015. We determined the number and percentage of patients experiencing MH status change within 7 days post procedure and the cumulative total by final follow-up (Mdn = 12 months).

RESULTS

Twenty-five studies met the inclusion criteria, which accounted for a total of 1,646 pASDC patients. Pre-procedure MH prevalence was 8% (126/1,646). Change in preexisting MH occurred in a total of 72% (91/126), 12% (11/91) within 7-days after pASDC; within follow-up MH improved in 14% (18/126), resolved in 37% (47/126), but persisted in 63% (79/126). De novo MH incidence ranged between 10 (153/1,520) and 18.3% (153/836); 34% incipience (52/153) was within 7-days of pASDC; females accounted for 80% (63/79) of gender differentiated cases; of type distinguished cases, 42% (51/122) were MH without aura (MO) and 58% (71/122) were MH with aura (MA); MH improved in 10% (16/153), resolved in 24% (37/153) but persisted beyond final follow-up in 76% (116/153). Antiplatelet agents were effective modulators of MH in 44% (11/25) studies. Possible adverse MH-predisposing traits were scarce: larger ASD size reported in ~2% (39/1,646) of patients experiencing de novo MH or preexisting MH exacerbation; short aortic rim reported in three de novo MH patients; allergic response to occluder nickel alloy in four patients with MH status change from baseline (de novo or preexisting MH change not specified).

INTERPRETATION

Early intensification of MH status change but later amelioration (virtually paralleling stages of endothelialization), relatively high efficacy of antiplatelet agents, and the emergence of MA as the dominant de novo MH type favor proinflammatory triggers of MH status change after pASDC.

Magnetic resonance imaging arterial-spin-labelling perfusion alterations in childhood migraine with atypical aura: a case-control study

AIM

Atypical migraine with aura can be challenging to diagnose. Arterial-spin-labelling (ASL) is able to non-invasively quantify brain perfusion. Our aim was to report cerebral blood flow (CBF) alterations using ASL, at the acute phase of atypical migraine with aura in children.

METHOD

Paediatric patients were retrospectively included if (1) referred for acute neurological deficit(s), (2) underwent brain magnetic resonance imaging (MRI) at presentation with ASL sequence, and (3) had subsequent diagnosis of migraine with aura. Neurological symptom-free controls were matched for age. Twenty-eight regions of interest (ROIs) were drawn on CBF maps for each participant/control.

RESULTS

Ten patients were included (median age 13y, range 8-16y). Eight of 10 had multiple aura symptoms during the episode. For every patient, CBF was decreased in a brain region consistent with symptoms when MRI was performed less than 14 hours after onset (n=7 patients) and increased if the MRI was performed 17 hours or more after (n=4 MRIs).

INTERPRETATION

MRI-ASL appears to be a promising tool for the diagnostic workup and differentials exclusion in paediatric migraine with aura. Constant and time-consistent non-territorial CBF modifications were found in our sample providing additional insight to migraine with aura pathophysiology. The authors encourage implementing this sequence at the acute phase of unexplained paediatric neurological deficits, with or without accompanying headache.

Genetic epidemiology of migraine and depression

Background

Migraine and major depressive disorder (commonly referred to as depression) are both common disorders with a significant impact on society. Studies in both clinical and community-based settings have demonstrated a strong relationship between migraine and depression. In addition to complicating the diagnosis, depression that is comorbid with migraine may lower treatment adherence, increase risk of medication overuse and is associated with migraine chronification, thus leading to higher direct and indirect costs and poorer health-related outcomes with increased disability.

Aim

The aim of this review is to summarise the current knowledge on the genetic epidemiology of migraine and depression and the possible biological mechanisms underlying their comorbidity.

Methods

We present a narrative review reporting on the current literature.

Results and conclusions

Epidemiological findings indicate that there is a bidirectional relationship between migraine and depression, with one disorder increasing the risk for the other and vice versa, suggesting shared biological mechanisms. Twin and family studies indicate that this bidirectional relationship can be explained, at least partly, by shared underlying genetically determined disease mechanisms. Although no genes have been robustly associated with the aetiology of both migraine and depression, genes from serotonergic, dopaminergic and GABAergic systems together with variants in the MTHFR and BDNF genes remain strong candidates.

Cervical non-invasive vagus nerve stimulation (nVNS) for preventive and acute treatment of episodic and chronic migraine and migraine-associated sleep disturbance: a prospective observational cohort study

Background

The debilitating nature of migraine and challenges associated with treatment-refractory migraine have a profound impact on patients. With the need for alternatives to pharmacologic agents, vagus nerve stimulation has demonstrated efficacy in treatment-refractory primary headache disorders. We investigated the use of cervical non-invasive vagus nerve stimulation (nVNS) for the acute treatment and prevention of migraine attacks in treatment-refractory episodic and chronic migraine (EM and CM) and evaluated the impact of nVNS on migraine-associated sleep disturbance, disability, and depressive symptoms.

Methods

Twenty patients with treatment-refractory migraine were enrolled in this 3-month, open-label, prospective observational study. Patients administered nVNS prophylactically twice daily at prespecified times and acutely as adjunctive therapy for migraine attacks. The following parameters were evaluated: pain intensity (visual analogue scale [VAS]); number of headache days per month and number of migraine attacks per month; number of acutely treated attacks; sleep quality (Pittsburgh Sleep Quality Index [PSQI]); migraine disability assessment (MIDAS); depressive symptoms (Beck Depression Inventory® [BDI]); and adverse events (AEs).

Results

Of the 20 enrolled patients, 10 patients each had been diagnosed with EM and CM. Prophylaxis with nVNS was associated with significant overall reductions in patient-perceived pain intensity; median (interquartile range) VAS scores at baseline versus 3 months were 8.0 (7.5, 8.0) versus 4.0 (3.5, 5.0) points (p < 0.001). Baseline versus 3-month values (mean ± standard error of the mean) were 14.7 ± 0.9 versus 8.9 ± 0.8 (p < 0.001) for the number of headache days per month and 7.3 ± 0.9 versus 4.5 ± 0.6 (p < 0.001) for the number of attacks per month. Significant improvements were also noted in MIDAS (p < 0.001), BDI (p < 0.001), and PSQI global (p < 0.001) scores. No severe or serious AEs occurred.

Conclusion

In this study, treatment with nVNS was safe and provided clinically meaningful decreases in the frequency and intensity of migraine attacks in patients with treatment-refractory migraine. Improvements in migraine-associated disability, depression, and sleep quality were also noted.

Source localization of intermittent rhythmic delta activity in a patient with acute confusional migraine: cross-spectral analysis using standardized low-resolution brain electromagnetic tomography (sLORETA)

Acute confusional migraine (ACM) shows typical electroencephalography (EEG) patterns of diffuse delta slowing and frontal intermittent rhythmic delta activity (FIRDA). The pathophysiology of ACM is still unclear but these patterns suggest neuronal dysfunction in specific brain areas. We performed source localization analysis of IRDA (in the frequency band of 1-3.5 Hz) to better understand the ACM mechanism. Typical IRDA EEG patterns were recorded in a patient with ACM during the acute stage. A second EEG was obtained after recovery from ACM. To identify source localization of IRDA, statistical non-parametric mapping using standardized low-resolution brain electromagnetic tomography was performed for the delta frequency band comparisons between ACM attack and non-attack periods. A difference in the current density maximum was found in the dorsal anterior cingulated cortex (ACC). The significant differences were widely distributed over the frontal, parietal, temporal and limbic lobe, paracentral lobule and insula and were predominant in the left hemisphere. Dorsal ACC dysfunction was demonstrated for the first time in a patient with ACM in this source localization analysis of IRDA. The ACC plays an important role in the frontal attentional control system and acute confusion. This dysfunction of the dorsal ACC might represent an important ACM pathophysiology.

Pediatric Headaches

Pediatric headaches are common, and many may never require intervention by a health care provider. However, migraines can become more difficult to treat, especially if they become chronic daily headaches. Pediatric headache is a subjective and unique experience that requires attention to both psychological and physiologic components in diagnosis and treatment. A biopsychosocial, multidisciplinary approach, including both medication management and psychological treatment, is considered essential for effective management.

BF-1--a novel selective 5-HT2B receptor antagonist blocking neurogenic dural plasma protein extravasation in guinea pigs

Serotonin 5-HT2B receptor antagonists have been proposed as migraine prophylactic drugs, but previously available 5-HT2B receptor antagonists displayed multiple monoaminergic side effects and had to be withdrawn from the market. Here, we set out to identify a novel antagonist with high affinity and selectivity towards 5-HT2B receptors. To test the affinity of new compounds towards various receptors, we generated a broad series of cells functionally coupling human monoaminergic receptors to luciferase. Using the cell lines we revealed pimethixene (1-methyl-4-(9H-thioxanthen-9-ylidene)piperidine) as highly potent, albeit non-selective 5-HT2B receptor antagonist and optimized its chemical structure to create highly potent and selective 5-HT2B receptor antagonists. We selected the methoxythioxanthene BF-1 for further analysis. In comparison to pimethixene, it lacked high affinities to 5-HT1A, 5-HT2A, 5-HT2C, histamine H1, dopamine D1 and D2 as well as muscarinic M1 and M2 receptors. BF-1 was tested as potential migraine prophylactic drug by blocking meta-chlorophenylpiperazine, (mCPP) or BW723C86 (5-((thiophen-2-yl)methoxy)-α-methyltryptamine) induced neurogenic dural plasma protein extravasation in a guinea pig model that may resemble a migraine attack. BF-1 was significantly more potent in this assay compared to the well know non-selective 5-HT2B antagonists, methysergide ((6aR,9R)-N-[(2S)-1-Hydroxybutan-2-yl]-4,7-dimethyl-6,6a,8,9-tetrahydroindolo[4,3-fg]quinoline-9-carboxamide) or pizotifen (4-(1-methyl-4-piperidylidine)-9,10-dihydro-4H-benzo-[4,5]cyclohepta[1,2]-thiophene). Therefore, we propose BF-1 as a new compound that may be developed for prophylactic migraine treatment without the typical monoaminergic side effects.

Lack of association between oxidative stress-related gene polymorphisms and chronic migraine in an Italian population

Migraine patients present increased risks of vascular diseases such as high blood pressure, insulin resistance, metabolic syndrome, stroke and coronary heart disease. Oxidative stress (OS) is increasingly being studied in relation to the pathophysiology of migraine, stimulated by the described association with the most frequent migraine comorbidities. Because many of the gene-encoded players of the OS balance are characterized by functional polymorphisms, it is supposed that the individual genomic profile could affect susceptibility to OS and to related pathophysiological conditions. This study aimed to characterize a panel of 10 polymorphisms in 8 OS-related genes in a chronic migraine (CM) population and healthy controls, to recognize a genetic risk in the process of migraine chronification. The sample consisted of 45 healthy women and 96 women diagnosed with CM. No deviations from the Hardy-Weinberg equilibrium were detected, or in the overall population, or in the CM group or in the control group.