Neurobiology of migraine

Posttraumatic Transient Neurologic Dysfunction: A Proposal for Pathophysiology

Unexplained neurological deterioration is occasionally observed in patients with traumatic brain injuries. We aimed to describe the clinical features of posttraumatic transient neurologic dysfunction and provide new insight into its pathophysiology. We retrospectively collected data from patients with focal neurologic deterioration of unknown origin during hospitalization for acute traumatic brain injury for 48 consecutive months. Brain imaging, including CT, diffusion weighted imaging and perfusion weighted imaging, and electroencephalography were conducted during the episodes. Fourteen (2.0%) patients experienced unexplained focal neurologic deterioration among 713 patients who were admitted for traumatic intracranial hemorrhage during the study period. Aphasia was the predominant symptom in all patients, and hemiparesis or hemianopia was accompanied in three patients. These symptoms developed within fourteen days after trauma. Structural imaging did not show any significant interval change, and electroencephalography showed persistent arrhythmic slowing in the corresponding hemisphere in most patients. Perfusion imaging revealed increased cerebral blood flow in the symptomatic hemisphere. Surgical intervention and anti-seizure medications were ineffective in abolishing the symptoms. The symptoms disappeared spontaneously after 4 hours to one month. Transient neurologic dysfunction can occur during the acute phase of traumatic brain injury. Although transient neurologic dysfunction may last longer than a typical transient ischemic attack or seizure, it eventually resolves regardless of treatment. Based on our observation, we postulate that this is a manifestation of spreading depolarization occurring in the injured brain, which is analogous to migraine aura.

Human hypoxia models in aerospace medicine: Potential applications for human pharmacological research

Aerospace medicine required controlled terrestrial models to investigate influences of altered atmosphere conditions, such as hypoxia, on human health and performance. These models could potentially be expanded to encompass disease conditions or treatment targets regulated through hypoxia or hypercapnia. Hypoxia, a condition in which the body is deprived of adequate oxygen supply, profoundly affects human physiology at multiple levels and contributes to the pathogenesis of various diseases. Experimental exposure to hypoxic conditions has gained recognition as a model for studying diseases such as pulmonary hypertension, chronic obstructive pulmonary disease, obstructive sleep apnoea, migraine and kidney disease. This approach may be particularly useful in mechanism-oriented early-stage clinical studies. This review discusses the ability of hypoxia models from space medicine research to mimic or induce these conditions in a controlled laboratory setting as a tool for testing the efficacy and safety of new pharmaceutical interventions.

Current Update on Categorization of Migraine Subtypes on the Basis of Genetic Variation: a Systematic Review

Migraine is a complex neurovascular disorder that is characterized by severe behavioral, sensory, visual, and/or auditory symptoms. It has been labeled as one of the ten most disabling medical illnesses in the world by the World Health Organization (Aagaard et al Sci Transl Med 6(237):237ra65, 2014). According to a recent report by the American Migraine Foundation (Shoulson et al Ann Neurol 25(3):252-9, 1989), around 148 million people in the world currently suffer from migraine. On the basis of presence of aura, migraine is classified into two major subtypes: migraine with aura (Aagaard et al Sci Transl Med 6(237):237ra65, 2014) and migraine without aura. (Aagaard K et al Sci Transl Med 6(237):237ra65, 2014) Many complex genetic mechanisms have been proposed in the pathophysiology of migraine but specific pathways associated with the different subtypes of migraine have not yet been explored. Various approaches including candidate gene association studies (CGAS) and genome-wide association studies (Fan et al Headache: J Head Face Pain 54(4):709-715, 2014). have identified the genetic markers associated with migraine and its subtypes. Several single nucleotide polymorphisms (Kaur et al Egyp J Neurol, Psychiatry Neurosurg 55(1):1-7, 2019) within genes involved in ion homeostasis, solute transport, synaptic transmission, cortical excitability, and vascular function have been associated with the disorder. Currently, the diagnosis of migraine is majorly behavioral with no focus on the genetic markers and thereby the therapeutic intervention specific to subtypes. Therefore, there is a need to explore genetic variants significantly associated with MA and MO as susceptibility markers in the diagnosis and targets for therapeutic interventions in the specific subtypes of migraine. Although the proper characterization of pathways based on different subtypes is yet to be studied, this review aims to make a first attempt to compile the information available on various genetic variants and the molecular mechanisms involved with the development of MA and MO. An attempt has also been made to suggest novel candidate genes based on their function to be explored by future research.

The chronicle of headache treatment throughout human history from trepanation to perisutural botulinum toxin injections

To provide a historic snapshot as regards the evolution of headache treatment throughout the human history, i.e. starting from trepanation to perisutural botulinum toxin (BoNT) injections. Ancient surgeons had aimed to reach the cranium with trepanation (a surgical operation) for headache. As BoNT inhibits the release of nociceptive and pro-inflammatory neuropeptides, it has been recently suggested as an effective alternative in the prophylactic treatment of chronic migraine headache. Chronic migraine is a complex neurological disorder for which the underlying pathophysiology is yet not totally explained. According to the generally accepted hypotheses, peripheral neurogenic activation and central trigeminal sensitization are the two main mechanisms through which its pain develops. Since the headache most commonly occurs around the perisutural areas, and as the primary pathogenesis stem from the meningeal nerve fibers; collateral sensorial branches of the meningeal nerves can be optimal paths to transport BoNT inside the cranium. Concerning the therapeutic efficacy, we anticipate that perisutural injections would be technically challenging with blind techniques and actually possible only if performed under an imaging guidance, e.g. very conveniently with high frequency ultrasound.

Sonographic guide for botulinum toxin injections for chronic migraine headache: EURO-MUSCULUS/USPRM approach

Application of botulinum toxin A (BoNT-A) into the muscles of the head and neck area has become a widespread and reliable treatment modality for chronic migraine. The mechanism of action for BoNT-A is the inhibition of acetylcholine and local nociceptive peptide release at the terminal nerve endings. Cranial sutures have the highest concentration of nociceptive structures; therefore BoNT-A injection into the suture lines - as opposed to head and neck muscles - has been proposed for the treatment of chronic migraine. Nerve endings in sutures rapidly absorb BoNT-A and transfer it across the afferent nerve fibers in dura mater via orthodromic and antidromic transmission. In this article, ultrasound-guided BoNT-A application around the cranial sutures will be illustrated. It is noteworthy that suture injections would be safer and more efficient when applied with such guidance.

Pharmacological interventions for prophylaxis of vestibular migraine

BACKGROUND

Vestibular migraine is a form of migraine where one of the main features is recurrent attacks of vertigo. These episodes are often associated with other features of migraine, including headache and sensitivity to light or sound. These unpredictable and severe attacks of vertigo can lead to a considerable reduction in quality of life. The condition is estimated to affect just under 1% of the population, although many people remain undiagnosed. A number of pharmacological interventions have been used or proposed to be used as prophylaxis for this condition, to help reduce the frequency of the attacks. These are predominantly based on treatments that are in use for headache migraine, with the belief that the underlying pathophysiology of these conditions is similar.

OBJECTIVES

To assess the benefits and harms of pharmacological treatments used for prophylaxis of vestibular migraine.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 23 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with definite or probable vestibular migraine comparing beta-blockers, calcium channel blockers, antiepileptics, antidepressants, diuretics, monoclonal antibodies against calcitonin gene-related peptide (or its receptor), botulinum toxin or hormonal modification with either placebo or no treatment. We excluded studies with a cross-over design, unless data from the first phase of the study could be identified.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) improvement in headache, 6) improvement in other migrainous symptoms and 7) other adverse effects. We considered outcomes reported at three time points: < 3 months, 3 to < 6 months, > 6 to 12 months. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included three studies with a total of 209 participants. One evaluated beta-blockers and the other two evaluated calcium channel blockers. We did not identify any evidence for the remaining interventions of interest. Beta-blockers versus placebo One study (including 130 participants, 61% female) evaluated the use of 95 mg metoprolol once daily for six months, compared to placebo. The proportion of people who reported improvement in vertigo was not assessed in this study. Some data were reported on the frequency of vertigo attacks at six months and the occurrence of serious adverse effects. However, this is a single, small study and for all outcomes the certainty of evidence was low or very low. We are unable to draw meaningful conclusions from the numerical results. Calcium channel blockers versus no treatment Two studies, which included a total of 79 participants (72% female), assessed the use of 10 mg flunarizine once daily for three months, compared to no intervention. All of the evidence for this comparison was of very low certainty. Most of our outcomes were only reported by a single study, therefore we were unable to conduct any meta-analysis. Some data were reported on improvement in vertigo and change in vertigo, but no information was available regarding serious adverse events. We are unable to draw meaningful conclusions from the numerical results, as these data come from single, small studies and the certainty of the evidence was very low.

AUTHORS CONCLUSIONS

There is very limited evidence from placebo-controlled randomised trials regarding the efficacy and potential harms of pharmacological interventions for prophylaxis of vestibular migraine. We only identified evidence for two of our interventions of interest (beta-blockers and calcium channel blockers) and all evidence was of low or very low certainty. Further research is necessary to identify whether these treatments are effective at improving symptoms and whether there are any harms associated with their use.

Pharmacological interventions for acute attacks of vestibular migraine

BACKGROUND

Vestibular migraine is a form of migraine where one of the main features is recurrent attacks of vertigo. These episodes are often associated with other features of migraine, including headache and sensitivity to light or sound. The unpredictable and severe attacks of vertigo can lead to a considerable reduction in quality of life. The condition is estimated to affect just under 1% of the population, although many people remain undiagnosed. A number of pharmacological interventions have been used, or proposed to be used, at the time of a vestibular migraine attack to help reduce the severity or resolve the symptoms. These are predominantly based on treatments that are in use for headache migraine, with the belief that the underlying pathophysiology of these conditions is similar.  OBJECTIVES: To assess the benefits and harms of pharmacological interventions used to relieve acute attacks of vestibular migraine.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 23 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with definite or probable vestibular migraine comparing triptans, ergot alkaloids, dopamine antagonists, antihistamines, 5-HT3 receptor antagonists, gepants (CGRP receptor antagonists), magnesium, paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs) with either placebo or no treatment.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) improvement in headache, 6) improvement in other migrainous symptoms and 7) other adverse effects. We considered outcomes reported at three time points: < 2 hours, 2 to 12 hours, > 12 to 72 hours. We used GRADE to assess the certainty of evidence for each outcome.  MAIN RESULTS: We included two RCTs with a total of 133 participants, both of which compared the use of triptans to placebo for an acute attack of vestibular migraine. One study was a parallel-group RCT (of 114 participants, 75% female). This compared the use of 10 mg rizatriptan to placebo. The second study was a smaller, cross-over RCT (of 19 participants, 70% female). This compared the use of 2.5 mg zolmitriptan to placebo.  Triptans may result in little or no difference in the proportion of people whose vertigo improves at up to two hours after taking the medication. However, the evidence was very uncertain (risk ratio 0.84, 95% confidence interval 0.66 to 1.07; 2 studies; based on 262 attacks of vestibular migraine treated in 124 participants; very low-certainty evidence). We did not identify any evidence on the change in vertigo using a continuous scale. Only one of the studies assessed serious adverse events. No events were noted in either group, but as the sample size was small we cannot be sure if there are risks associated with taking triptans for this condition (0/75 receiving triptans, 0/39 receiving placebo; 1 study; 114 participants; very low-certainty evidence).  AUTHORS' CONCLUSIONS: The evidence for interventions used to treat acute attacks of vestibular migraine is very sparse. We identified only two studies, both of which assessed the use of triptans. We rated all the evidence as very low-certainty, meaning that we have little confidence in the effect estimates and cannot be sure if triptans have any effect on the symptoms of vestibular migraine. Although we identified sparse information on potential harms of treatment in this review, the use of triptans for other conditions (such as headache migraine) is known to be associated with some adverse effects.  We did not identify any placebo-controlled randomised trials for other interventions that may be used for this condition. Further research is needed to identify whether any interventions help to improve the symptoms of vestibular migraine attacks and to determine if there are side effects associated with their use.

CGRP physiology, pharmacology, and therapeutic targets: migraine and beyond

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse physiological functions. Its two isoforms (α and β) are widely expressed throughout the body in sensory neurons as well as in other cell types, such as motor neurons and neuroendocrine cells. CGRP acts via at least two G protein-coupled receptors that form unusual complexes with receptor activity-modifying proteins. These are the CGRP receptor and the AMY1 receptor; in rodents, additional receptors come into play. Although CGRP is known to produce many effects, the precise molecular identity of the receptor(s) that mediates CGRP effects is seldom clear. Despite the many enigmas still in CGRP biology, therapeutics that target the CGRP axis to treat or prevent migraine are a bench-to-bedside success story. This review provides a contextual background on the regulation and sites of CGRP expression and CGRP receptor pharmacology. The physiological actions of CGRP in the nervous system are discussed, along with updates on CGRP actions in the cardiovascular, pulmonary, gastrointestinal, immune, hematopoietic, and reproductive systems and metabolic effects of CGRP in muscle and adipose tissues. We cover how CGRP in these systems is associated with disease states, most notably migraine. In this context, we discuss how CGRP actions in both the peripheral and central nervous systems provide a basis for therapeutic targeting of CGRP in migraine. Finally, we highlight potentially fertile ground for the development of additional therapeutics and combinatorial strategies that could be designed to modulate CGRP signaling for migraine and other diseases.

Evolutionary game model of migraine based on the human brain hypersensitivity

Based on all studies published up to 2020, the prevalence of migraine worldwide is approximately 14%, although it varies regionally. Despite being one of the most disabling diseases, migraine still exists through natural selection and is prevalent today. This raises the question of what evolutionary advantages have led to the survival of migraine. The ultimate answer to this question should be found in evolution; however, there is no clear explanation yet. Notably, all the genes that cause migraine make the sensory organs and cortex of the migraine sufferer hypersensitive. In a state of hypersensitivity, the brain could recognize external threats easily. Game theory is a useful tool for explaining evolution in terms of genes. Just as the Hawk–Dove game, which has two strategies (aggressive and passive) and four fitness values, an evolutionary game between a migraineur and a non-migraineur, which shows two phenotypes (more sensitive and less sensitive) and four fitness values, can be played if a migraineur quickly recognizes a predator and informs a non-migraineur of its appearance and the non-migraineur later helps the migraineur escape from danger. This study aimed to explore the evolutionary mechanics of migraine that can be modeled. Furthermore, it tried to define why the human brain's hypersensitivity is a prerequisite for developing this evolutionary game model.

Gender and Neurosteroids: Implications for Brain Function, Neuroplasticity and Rehabilitation

Neurosteroids are synthesized de novo in the nervous system; they mainly moderate neuronal excitability, and reach target cells via the extracellular pathway. The synthesis of neurosteroids occurs in peripheral tissues such as gonads tissues, liver, and skin; then, because of their high lipophilia, they cross the blood-brain barrier and are stored in the brain structure. Neurosteroidogenesis occurs in brain regions such as the cortex, hippocampus, and amygdala by enzymes necessary for the in situ synthesis of progesterone from cholesterol. Neurosteroids could be considered the main players in both sexual steroid-induced hippocampal synaptic plasticity and normal transmission in the hippocampus. Moreover, they show a double function of increasing spine density and enhancing long term potentiation, and have been related to the memory-enhancing effects of sexual steroids. Estrogen and progesterone affect neuronal plasticity differently in males and females, especially regarding changes in the structure and function of neurons in different regions of the brain. Estradiol administration in postmenopausal women allowed for improving cognitive performance, and the combination with aerobic motor exercise seems to enhance this effect. The paired association between rehabilitation and neurosteroids treatment could provide a boosting effect in order to promote neuroplasticity and therefore functional recovery in neurological patients. The aim of this review is to investigate the mechanisms of action of neurosteroids as well as their sex-dependent differences in brain function and their role in neuroplasticity and rehabilitation.

A systematic review and meta-analysis of voxel-based morphometric studies of migraine

OBJECTIVES

To comprehensively summarize and meta-analyze the concurrence across voxel-based morphometric (VBM) neuroimaging studies of migraine.

METHODS

Neuroimaging studies published from origin to August 1, 2021 were searched in six databases including PubMed, Web of Science, Excerpta Medica Database (EMBASE), China National Knowledge Infrastructure (CNKI), Wanfang Database, and Chongqing VIP. Study selection, quality assessment, and data extraction were conducted by two independent researchers. Anisotropic effect size-signed differential mapping (AES-SDM) and activation likelihood estimation (ALE) were used to perform the meta-analysis of available studies reporting whole-brain gray matter (GM) structural data in migraine patients. Clinical variables correlation analysis and migraine subgroup analysis were also conducted.

RESULTS

40 articles were included after the strict screening, containing 1616 migraine patients and 1681 matched healthy subjects (HS) in total. Using the method of AES-SDM, migraine patients showed GM increase in the bilateral amygdala, the bilateral parahippocampus, the bilateral temporal poles, the bilateral superior temporal gyri, the left hippocampus, the right superior frontal gyrus, and the left middle temporal gyrus, as well as GM decrease in the left insula, the bilateral cerebellum (hemispheric lobule IX), the right dorsal medulla, the bilateral rolandic operculum, the right middle frontal gyrus, and the right inferior parietal gyrus. Using the method of ALE, migraine patients showed GM increase in the left parahippocampus and GM decrease in the left insula. The results of correlation analysis showed that many of these brain regions were associated with migraine headache frequency and migraine disease duration. Migraine patients in different subtypes (such as migraine without aura (MwoA), migraine with aura (MwA), episodic migraine (EM), chronic migraine (CM), vestibular migraine (VM), etc.), and in different periods (in the ictal and interictal periods) presented not entirely consistent GM alterations.

CONCLUSION

Migraine patients have GM alterations in multiple brain regions associated with sensation, affection, cognition, and descending modulation aspects of pain. These changes might be a consequence of repeated migraine attacks. Further studies are required to determine how these GM changes can be used to diagnose, monitor disease progression, or exploit potential therapeutic interventions for migraine patients.

Regulation of presynaptic Ca2+ channel abundance at active zones through a balance of delivery and turnover

Voltage-gated Ca²⁺ channels (VGCCs) mediate Ca²⁺ influx to trigger neurotransmitter release at specialized presynaptic sites termed active zones (AZs). The abundance of VGCCs at AZs regulates neurotransmitter release probability (P_r), a key presynaptic determinant of synaptic strength. Although biosynthesis, delivery, and recycling cooperate to establish AZ VGCC abundance, experimentally isolating these distinct regulatory processes has been difficult. Here, we describe how the AZ levels of cacophony (Cac), the sole VGCC-mediating synaptic transmission in Drosophila, are determined. We also analyzed the relationship between Cac, the conserved VGCC regulatory subunit α2δ, and the core AZ scaffold protein Bruchpilot (BRP) in establishing a functional AZ. We find that Cac and BRP are independently regulated at growing AZs, as Cac is dispensable for AZ formation and structural maturation, and BRP abundance is not limiting for Cac accumulation. Additionally, AZs stop accumulating Cac after an initial growth phase, whereas BRP levels continue to increase given extended developmental time. AZ Cac is also buffered against moderate increases or decreases in biosynthesis, whereas BRP lacks this buffering. To probe mechanisms that determine AZ Cac abundance, intravital FRAP and Cac photoconversion were used to separately measure delivery and turnover at individual AZs over a multi-day period. Cac delivery occurs broadly across the AZ population, correlates with AZ size, and is rate-limited by α2δ. Although Cac does not undergo significant lateral transfer between neighboring AZs over the course of development, Cac removal from AZs does occur and is promoted by new Cac delivery, generating a cap on Cac accumulation at mature AZs. Together, these findings reveal how Cac biosynthesis, synaptic delivery, and recycling set the abundance of VGCCs at individual AZs throughout synapse development and maintenance.

Abnormalities in resting-state EEG microstates are a vulnerability marker of migraine

Background

Resting-state EEG microstates are thought to reflect brief activations of several interacting components of resting-state brain networks. Surprisingly, we still know little about the role of these microstates in migraine. In the present study, we attempted to address this issue by examining EEG microstates in patients with migraine without aura (MwoA) during the interictal period and comparing them with those of a group of healthy controls (HC).

Methods

Resting-state EEG was recorded in 61 MwoA patients (50 females) and 66 HC (50 females). Microstate parameters were compared between the two groups. We computed four widely identified canonical microstate classes A-D.

Results

Microstate classes B and D displayed higher time coverage and occurrence in the MwoA patient group than in the HC group, while microstate class C exhibited significantly lower time coverage and occurrence in the MwoA patient group. Meanwhile, the mean duration of microstate class C was significantly shorter in the MwoA patient group than in the HC group. Moreover, among the MwoA patient group, the duration of microstate class C correlated negatively with clinical measures of headache-related disability as assessed by the six-item Headache Impact Test (HIT-6). Finally, microstate syntax analysis showed significant differences in transition probabilities between the two groups, primarily involving microstate classes B, C, and D.

Conclusions

By exploring EEG microstate characteristics at baseline we were able to explore the neurobiological mechanisms underlying altered cortical excitability and aberrant sensory, affective, and cognitive processing, thus deepening our understanding of migraine pathophysiology.

Pharmacological interventions for prophylaxis of vestibular migraine

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the benefits and harms of pharmacological treatments used for prophylaxis of vestibular migraine.

Stabilization of negative activation voltages of Cav1.3 L-Type Ca2+-channels by alternative splicing

-->Low voltage-activated Cav1.3 L-type Ca2+-channels are key regulators of neuronal excitability controlling neuronal development and different types of learning and memory. Their physiological functions are enabled by their negative activation voltage-range, which allows Cav1.3 to be active at subthreshold voltages. Alternative splicing in the C-terminus of their pore-forming α1-subunits gives rise to C-terminal long (Cav1.3L) and short (Cav1.3S) splice variants allowing Cav1.3S to activate at even more negative voltages than Cav1.3L. We discovered that inclusion of exons 8b, 11, and 32 in Cav1.3S further shifts activation (-3 to -4 mV) and inactivation (-4 to -6 mV) to more negative voltages as revealed by functional characterization in tsA-201 cells. We found transcripts of these exons in mouse chromaffin cells, the cochlea, and the brain. Our data further suggest that Cav1.3-containing exons 11 and 32 constitute a significant part of native channels in the brain. We therefore investigated the effect of these splice variants on human disease variants. Splicing did not prevent the gating defects of the previously reported human pathogenic variant S652L, which further shifted the voltage-dependence of activation of exon 11-containing channels by more than -12 mV. In contrast, we found no evidence for gating changes of the CACNA1D missense variant R498L, located in exon 11, which has recently been identified in a patient with an epileptic syndrome. Our data demonstrate that alternative splicing outside the C-terminus involving exons 11 and 32 contributes to channel fine-tuning by stabilizing negative activation and inactivation gating properties of wild-type and mutant Cav1.3 channels.

Therapeutic Potential of MRGPRX2 Inhibitors on Mast Cells

Mast cells (MCs) act as primary effectors in inflammatory and allergic reactions by releasing intracellularly-stored inflammatory mediators in diseases. The two major pathways for MC activation are known to be immunoglobulin E (IgE)-dependent and -independent. Although IgE-dependent signaling is the main pathway to MC activation, IgE-independent pathways have also been found to serve pivotal roles in the pathophysiology of various inflammatory conditions. Recent studies have shown that human and mouse MCs express several regulatory receptors such as toll-like receptors (TLRs), CD48, C300a, and GPCRs, including mas-related GPCR-X2 (MRGPRX2). MRGPRX2 has been reported as a novel GPCR that is expressed in MCs activated by basic secretagogues, neurokinin peptides, host defense antimicrobial peptides, and small molecule compounds (e.g., neuromuscular blocking agents) and leads to MC degranulation and eicosanoids release under in vitro experimental condition. Functional analyses of MRGPRX2 and Mrgprb2 (mouse ortholog) indicate that MRGPRX2 is involved in MC hypersensitivity reactions causing neuroinflammation such as postoperative pain, type 2 inflammation, non-histaminergic itch, and drug-induced anaphylactic-like reactions. In this review, we discuss the roles in innate immunity through functional studies on MRGPRX2-mediated IgE-independent MC activation and also the therapeutic potential of MRGPRX2 inhibitors on allergic and inflammatory diseases.

Efficacy and safety of exogenous beta-hydroxybutyrate for preventive treatment in episodic migraine: A single-centred, randomised, placebo-controlled, double-blind crossover trial

BACKGROUND

Several studies propose that brain energy deficit might be partially involved in the pathophysiology of migraine. Previously, studies demonstrated that ketogenic diet causes a substantial reduction in migraine frequency. Since the ketogenic diet is restricting and its adherence is difficult, we proposed to supplement ketone bodies exogenously to provide a prophylactic effect in migraineurs.

AIM

To evaluate the prophylactic effect of exogenous DL-beta-hydroxybutyrate supplementation in episodic migraineurs.

METHODS

A double-blind, placebo-controlled, randomised crossover trial was conducted, involving 41 patients with episodic migraine. Patients were randomised 1:1 into placebo or beta-hydroxybutyrate group before entering the first treatment period. Each treatment period was 12 weeks long, followed by four weeks of washout phase and four weeks of run-in phase before entering into the corresponding second treatment period. The primary endpoint was the number of migraine days in the last four weeks of treatment, adjusted for baseline.

RESULTS

We observed no clinically significant amelioration of migraine frequency or intensity under DL-beta-hydroxybutyrate treatment as compared to placebo regarding number of migraine days (mean difference [95% CI]: -1.1[-5.07, 2.85]), migraine intensity (0-10 VAS: 1.5[-0.8, 3.7]).

CONCLUSION

The selected dose of supplemented exogenous DL-beta-hydroxybutyrate did not demonstrate efficacy in episodic migraineurs.ClinicalTrials.gov Identifier: NCT03132233.

Mutations in the Voltage Dependent Calcium Channel CACNA1A (P/Q type alpha 1A subunit) Causing Neurological Disorders - An Overview

Background

The voltage-dependent calcium channel α1 subunit (CACNA1A) gene plays a major role in neuronal communication. Mutation in this gene results in altered Ca²⁺ ion influx that modify the neurotransmitter release resulting in the development of various neurological disorders like hemiplegic migraine with cortical spreading depression, epilepsy, episodic ataxia type 2, and spinocerebellar ataxia type 6.

Objective

This review aimed in portraying the frequent mutations in CACNA1A gene causing hemiplegic migraine with cortical spreading depression, epilepsy, episodic ataxia type 2 and spinocerebellar ataxia type 6.

Methodology

A systematic search has been adopted in various databases using the keywords "Calcium channel," "migraine," "epilepsy," "episodic ataxia," and "spinocerebellar ataxia" for writing this review that collectively focuses on mutations in the CACNA1A gene causing the common neurological diseases from 1975 to 2019.

Conclusion

Every type of mutation has its own signature in gene functioning and understanding them might aid knowing more in disease progression.

[The Second Short Form of the McGill Pain Questionnaire as the useful additional tool for differential diagnostics of migraine and cervicogenic headache]

OBJECTIVE

To study the effectiveness of the Second Short Form of the McGill Pain Questionnaire (SF-MPQ-2) as an instrument for assessment and comparison of quantitative characteristics of pain in patients with chronic musculoskeletal impairment of the cervical spine and nonspecific neck pain accompanied by chronic migraine or cervicogenic headache (CeH).

MATERIAL AND METHODS

Forty-nine patients, aged from 19 to 60 years (mean age 42.8±10.4), were divided into 2 comparable by age and gender groups with migraine (n=18) and CeH (n=31). Neck pain and headache intensity was measured by the 11-points Numerical Rating Scale (NRS). Quality of pain and related symptoms were measured by SF-MPQ-2. Multidisciplinary and multimodal approaches were applied for treatment, including several modalities of manual therapy.

RESULTS

Headache intensity was higher in the migraine group in comparison with the CeH group (7.8±1.7 vs 6.0±1.5, respectively; p<0.05). No significant differences in neck pain intensity were found (6.2±1.8 vs 5.3±1.7; p=0.08). Patients with migraine usually chose more descriptors than patients with CeH (14 vs 4, respectively) and higher range of their intensity (p<0.001). By the end of treatment session, the number of descriptors and their intensity decreased significantly on all SF=MPQ-2 scales (p<0.001) in both groups. Most patients of migraine and CeH group were satisfied with treatment (83% and 97%, respectively) and marked «much improved» and «very much improved» on the 7-point Patient Global Impression of Change scale.

CONCLUSION

SF-MPQ-2 is a useful tool for differential diagnosis of migraine and CeH, as it contains the sufficient number of descriptors and the scale for measuring their intensity.

Voltage-Gated Ca2+-Channel α1-Subunit de novo Missense Mutations: Gain or Loss of Function - Implications for Potential Therapies

This review summarizes our current knowledge of human disease-relevant genetic variants within the family of voltage gated Ca2+ channels. Ca2+ channelopathies cover a wide spectrum of diseases including epilepsies, autism spectrum disorders, intellectual disabilities, developmental delay, cerebellar ataxias and degeneration, severe cardiac arrhythmias, sudden cardiac death, eye disease and endocrine disorders such as congential hyperinsulinism and hyperaldosteronism. A special focus will be on the rapidly increasing number of de novo missense mutations identified in the pore-forming α1-subunits with next generation sequencing studies of well-defined patient cohorts. In contrast to likely gene disrupting mutations these can not only cause a channel loss-of-function but can also induce typical functional changes permitting enhanced channel activity and Ca2+ signaling. Such gain-of-function mutations could represent therapeutic targets for mutation-specific therapy of Ca2+-channelopathies with existing or novel Ca2+-channel inhibitors. Moreover, many pathogenic mutations affect positive charges in the voltage sensors with the potential to form gating-pore currents through voltage sensors. If confirmed in functional studies, specific blockers of gating-pore currents could also be of therapeutic interest.

The de novo CACNA1A pathogenic variant Y1384C associated with hemiplegic migraine, early onset cerebellar atrophy and developmental delay leads to a loss of Cav2.1 channel function

CACNA1A pathogenic variants have been linked to several neurological disorders including familial hemiplegic migraine and cerebellar conditions. More recently, de novo variants have been associated with severe early onset developmental encephalopathies. CACNA1A is highly expressed in the central nervous system and encodes the pore-forming Ca_Vα₁ subunit of P/Q-type (Cav2.1) calcium channels. We have previously identified a patient with a de novo missense mutation in CACNA1A (p.Y1384C), characterized by hemiplegic migraine, cerebellar atrophy and developmental delay. The mutation is located at the transmembrane S5 segment of the third domain. Functional analysis in two predominant splice variants of the neuronal Cav2.1 channel showed a significant loss of function in current density and changes in gating properties. Moreover, Y1384 variants exhibit differential splice variant-specific effects on recovery from inactivation. Finally, structural analysis revealed structural damage caused by the tyrosine substitution and changes in electrostatic potentials.

Different Chinese patent medicine therapies for migraine: A protocol for systematic review and network meta-analysis

BACKGROUND

Migraine is a clinically high incidence rate of neurovascular disease. It is a recurrent headache. It is characterized by nausea, vomiting, fear of voice, and photophobia. Nowadays, a large number of randomized controlled clinical studies have shown that Chinese patent medicine has the advantages of good curative effect and high safety in the treatment of migraine. However, due to the variety of proprietary Chinese medicines, their relative effectiveness and safety have not yet been verified. Therefore, this study will use the network meta-analysis method to verify the effectiveness and safety of different kinds of Chinese patent medicines in the treatment of migraine.

METHODS

All randomized controlled trials of Toutongning capsule, Yangxue Qingnao granule, naoxintong capsules, Tianmagouteng granules in the treatment of migraine were searched from PubMed, Cochrane Library, web of science, EMBASE, sinomed, CNKI, Wanfang database, VIP. The retrieval time is from the establishment of the database to November 18, 2020. In order to avoid omission, we will manually retrieve relevant references and conference papers. According to the inclusion and exclusion criteria, we evaluated the quality and risk of all the retrieved literatures. Methodological quality assessment and bias risk will be assessed using the Cochrane bias risk tool. Revman 5.3, WinBUGS 1.4.3, and stata14.2 software will be used for all data analysis.

RESULTS

This study will directly or indirectly compare the effectiveness of different interventions on migraine outcome indicators, and rank the effectiveness. The main outcome measures included total effective rate (total effective rate = rocovery + obvious effective + effective/total number of cases × 100%), visual analogue scale (VAS) score, and secondary outcome indicators included analgesic effect evaluation index and quality of life scale.

CONCLUSION

To provide evidence for evidence-based medicine and clinical researchers to choose more effective Chinese patent medicines to treat migraine.

A CACNA1A variant associated with trigeminal neuralgia alters the gating of Cav2.1 channels

A novel missense mutation in the CACNA1A gene that encodes the pore forming α₁ subunit of the Ca_V2.1 voltage-gated calcium channel was identified in a patient with trigeminal neuralgia. This mutation leads to a substitution of proline 2455 by histidine (P2455H) in the distal C-terminus region of the channel. Due to the well characterized role of this channel in neurotransmitter release, our aim was to characterize the biophysical properties of the P2455H variant in heterologously expressed Ca_V2.1 channels. Whole-cell patch clamp recordings of wild type and mutant Ca_V2.1 channels expressed in tsA-201 cells reveal that the mutation mediates a depolarizing shift in the voltage-dependence of activation and inactivation. Moreover, the P2455H mutant strongly reduced calcium-dependent inactivation of the channel that is consistent with an overall gain of function. Hence, the P2455H Ca_V2.1 missense mutation alters the gating properties of the channel, suggesting that associated changes in Ca_V2.1-dependent synaptic communication in the trigeminal system may contribute to the development of trigeminal neuralgia.

Response inhibition alterations in migraine: evidence from event-related potentials and evoked oscillations

BACKGROUND

Migraine is characterized by a hypersensitivity to environmental stimulation which climaxes during headache attacks but persists during attack-free period. Despite ongoing debates about the nature of the mechanisms giving rise to this abnormality, the presence of deficient inhibitory cortical processes has been proposed to be one possible mechanism underlying its pathogenesis. Empirical evidence supporting this claim is mainly based on previous accounts showing functional cortical disexcitability in the sensory domain. Considering that a general inhibitory control process can play an important role across early to later stage of information processing, this may indicate the important role other dimensions of inhibitory control can play in migraine disability. The present study examined the pathophysiological features of inhibitory control that takes place during suppression of prepotent responses in migraineurs.

METHODS

Twenty-two patients with migraine without aura (mean age = 30.86 ± 5.69 years; 19 females) during the interictal period and 25 healthy controls (mean age = 30.24 ± 3.52 years; 18 females) were recruited. We used a stop signal task in combination with event-related potentials (ERPs) to examine participants' neural activity supporting response inhibition.

RESULTS

Behaviorally, migraineurs exhibited prolonged stop signal reaction times relative to healthy controls. At the neural level, the amplitude of the stop-N2 over fronto-central, central and centro-parietal scalp regions, a component of the ERPs related to conflict monitoring during early, non-motoric stages of inhibition, was significantly increased in migraineurs. Meanwhile, the amplitude of the stop-P3 over central and centro-parietal scalp regions, a component of the ERPs reflecting late-stage inhibition of the motor system and cognitive evaluation of motor inhibition, was also significantly increased in migraineurs. Ultimately, our time-frequency analysis further revealed increased delta activity in migraineurs.

CONCLUSIONS

Consistent with the theory that alterations in cognitive cortical processes are a key signature of migraine, our findings revealed an abnormal state of suppressing prepotent responses in migraineurs, which can be attributed to cortical disexcitability of the pre-frontal executive network and centro-parietal sensorimotor network. These novel findings extend to show the existence of dysfunctional inhibition control that occurs during suppression of prepotent responses in migraneurs.

Stimulation of Posterior Thalamic Nuclei Induces Photophobic Behavior in Mice

OBJECTIVE

A hallmark of migraine is photophobia. In mice, photophobia-like behavior is induced by calcitonin gene-related peptide (CGRP), a neuropeptide known to be a key player in migraine. In this study, we sought to identify sites within the brain from which CGRP could induce photophobia.

DESIGN

We focused on the posterior thalamic region, which contains neurons responsive to both light and dural stimulation and has CGRP binding sites. We probed this area with both optogenetic stimulation and acute CGRP injections in wild-type mice. Since the light/dark assay has historically been used to investigate anxiety-like responses in animals, we measured anxiety in a light-independent open field assay and asked if stimulation of a brain region, the periaqueductal gray, that induces anxiety would yield similar results to posterior thalamic stimulation. The hippocampus was used as an anatomical control to ensure that light-aversive behaviors could not be induced by the stimulation of any brain region.

RESULTS

Optogenetic activation of neuronal cell bodies in the posterior thalamic nuclei elicited light aversion in both bright and dim light without an anxiety-like response in an open field assay. Injection of CGRP into the posterior thalamic region triggered similar light-aversive behavior without anxiety. In contrast to the posterior thalamic nuclei, optogenetic stimulation of dorsal periaqueductal gray cell bodies caused both light aversion and an anxiety-like response, while CGRP injection had no effect. In the dorsal hippocampus, neither optical stimulation nor CGRP injection affected light aversion or open field behaviors.

CONCLUSION

Stimulation of posterior thalamic nuclei is able to initiate light-aversive signals in mice that may be modulated by CGRP to cause photophobia in migraine.

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.

Analysis of Genetic Variants in SCN1A, SCN2A, KCNK18, TRPA1 and STX1A as a Possible Marker of Migraine

Background

Migraine is a polygenetic disease, considered as a channelopathy. The dysregulation of ion functioning due to genetic changes may activate the trigeminovascular system and induce migraine attack both migraine with aura (MA) and without aura (MO).

Objectives

The aim of the study was to analyze the following variants of genes encoding ion channels and associated protein: c.3199G>A SCN1A, c.56G>A SCN2A, c.28A>G and c.328T>C KCNK18, c.3053A>G TRPA1, c.31-1811C>T STX1A in migraine patients.

Patients and Methods

The study included 170 migraine patients and 173 controls. HRMA and Sanger sequencing were used for genotyping. Meta-analysis was performed for c.28A>G, c.328T>C KCNK18, and c.31-1811C>T STX1A.

Results

AA genotype of c.56G>A SCN2A was found only in migraine patients. Patients with c.328T>C KCNK18 mutation had an increased risk of developing migraine before the age of 18. Moreover, individuals with AA/TC haplotype of KCNK18 had higher attack frequency than those with AA/TT (p<0.05). T allele of c.31-1811C>T STX1A was more frequent in MA patients than MO (p<0.05). The c.3053A>G TRPA1 polymorphism was more common in patients with migraine onset before the age of 15 (p<0.05), while c.31-1811C>T STX1A and c.3199G>A SCN1A before the age of 10 (p<0.01). Meta-analysis showed a significant association of c.31-1811C>T STX1A polymorphism with migraine overall (OR=1.22, p=0.0086), MA, and MO. No association was found for c.28A>G KCNK18, c.328T>C KCNK18, and migraine overall.

Conclusion

Changes in genes encoding ion channels or proteins regulating their functioning may increase the risk of migraines and correlate with clinical features of disease, e.g. age of onset and attack frequency.

A Comprehensive Review of Over-the-counter Treatment for Chronic Migraine Headaches

PURPOSE OF REVIEW

Migraine headaches are a neurologic disorder characterized by attacks of moderate to severe throbbing headache that are typically unilateral, exacerbated by physical activity, and associated with phonophobia, photophobia, nausea, and vomiting. In the USA, the overall age-adjusted prevalence of migraine in female and male adults is 22.3% and 10.8%, respectively.

RECENT FINDINGS

Migraine is a disabling disease that ranks as the 8th most burdensome disease in the world and the 4th most in women. The overarching hypothesis of migraine pathophysiology describes migraine as a disorder of the pain modulating system, caused by disruptions of the normal neural networks of the head. The activation of these vascular networks results in meningeal vasodilation and inflammation, which is perceived as head pain. The primary goals of acute migraine therapy are to reduce attack duration and severity. Current evidence-based therapies for acute migraine attacks include acetaminophen, four nonsteroidal anti-inflammatory drugs (NSAIDs), seven triptans, NSAID-triptan combinations, dihydroergotamine, non-opioid combination analgesics, and several anti-emetics. Over-the-counter medications are an important component of migraine therapy and are considered a first-line therapy for most migraineurs. These medications, such as acetaminophen, ibuprofen, naproxen, and aspirin, have shown strong efficacy when used as first-line treatments for mild-to-moderate migraine attacks. The lower cost of over-the-counter medications compared with prescription medications also makes them a preferred therapy for some patients. In addition to their efficacy and lower cost, over-the-counter medications generally have fewer and less severe adverse effects, have more favorable routes of administration (oral vs. subcutaneous injection), and reduced abuse potential. The purpose of this review is to provide a comprehensive evidence-based update of over-the-counter pharmacologic options for chronic migraines.

Video head impulse test in vestibular migraine

Introduction

Vestibular migraine as an entity was described in 1999 and its pathophysiology is still not established. Simultaneously with research to better understand vestibular migraine, there has been an improvement in vestibular function assessment. The video-head impulse test is one of the latest tools to evaluate vestibular function, measuring its vestibular-ocular reflex gain.

Objective

To evaluate vestibular function of vestibular migraine patients using video-head impulse test.

Methods

Cross-sectional case-control study homogeneous by age and gender with vestibular migraine patients according to the 2012–2013 Barany Society/International Headache Society diagnostic criteria submitted to video-head impulse test during intercrisis period.

Results

31 vestibular migraine patients were evaluated with a predominantly female group (90.3%) and mean age of 41 years old. Vestibular function was normal in both patient and control groups. Gain values for horizontal canals were similar between the two groups, but gain values for vertical canals were higher in the group with vestibular migraine (p < 0.05). Patients with vestibular migraine felt more dizziness while performing the video-head impulse test than control subjects (p < 0.001).

Conclusions

Patients with vestibular migraine present normal vestibular function during intercrisis period when evaluated by video-head impulse test. Vertical canals, however, have higher gains in patients with vestibular migraine than in control subjects. Vestibular migraine patients feel dizziness more often while conducting video-head impulse test.

Familial analysis reveals rare risk variants for migraine in regulatory regions

The most recent genome-wide association study of migraine increased the total number of known migraine risk loci to 38. Still, most of the heritability of migraine remains unexplained, and it has been suggested that rare gene dysregulatory variants play an important role in migraine etiology. Addressing the missing heritability of migraine, we aim to fine-map signals from the known migraine risk loci to regulatory mechanisms and associate these to downstream genic targets. We analyzed a large cohort of whole-genome sequenced patients from extended migraine pedigrees (1040 individuals from 155 families). We test for association between rare variants segregating in regulatory regions with migraine. The findings were replicated in an independent case-control cohort (2027 migraineurs, 1650 controls). We report an increased burden of rare variants in one CpG island and three polycomb group response elements near four migraine risk loci. We found that the association is independent of the common risk variants in the loci. The regulatory regions are suggested to affect different genes than those originally tagged by the index SNPs of the migraine loci. Families with familial clustering of migraine have an increased burden of rare variants in regulatory regions near known migraine risk loci, with effects that are independent of the variants in the loci. The possible regulatory targets suggest different genes than those originally tagged by the index SNPs of the migraine loci.

Genetic variants in migraine: a field synopsis and systematic re-analysis of meta-analyses

Objective

Numerous genetic variants from meta-analyses of observational studies and GWAS were reported to be associated with migraine susceptibility. However, due to the random errors in meta-analyses, the noteworthiness of the results showing statistically significant remains doubtful. Thus, we performed this field synopsis and re-analysis study to evaluate the noteworthiness using a Bayesian approach in hope of finding true associations.

Methods

Relevant meta-analyses from observational studies and GWAS examining correlation between all genetic variants and migraine risk were included in our study by a PubMed search. Identification of noteworthy associations were analyzed by false-positive rate probability (FPRP) and Bayesian false discovery probability (BFDP). Using noteworthy variants, GO enrichment analysis were conducted through DAVID online tool. Then, the PPI network and hub genes were performed using STRING database and CytoHubba software.

Results

As for 8 significant genetic variants from observational studies, none of which showed noteworthy at prior probability of 0.001. Out of 47 significant genetic variants in GWAS, 36 were noteworthy at prior probability of 0.000001 via FPRP or BFDP. We further found the pathways “positive regulation of cytosolic calcium ion concentration” and “inositol phosphate-mediated signaling” and hub genes including MEF2D, TSPAN2, PHACTR1, TRPM8 and PRDM16 related to migraine susceptibility.

Conclusion

Herein, we have identified several noteworthy variants for migraine susceptibility in this field synopsis. We hope these data would help identify novel genetic biomarkers and potential therapeutic target for migraine.

Calcitonin Gene-Related Peptide Antagonists for the Prevention of Migraine: Highlights From Pivotal Studies and the Clinical Relevance of This New Drug Class

Objective: To review the new drug class of calcitonin gene-related peptide antagonists (monoclonal antibodies) and their clinical relevance in migraine prophylaxis. Data Sources: A literature search was performed in PubMed (January 2009 to November 2019) using the terms migraine, calcitonin gene-related peptide (CGRP), erenumab, fremanezumab, and galcanezumab for clinical trials and studies. Study Selection and Data Extraction: Reports from human studies in English were evaluated for clinical evidence supporting pharmacology, efficacy, and adverse events. Initial pharmacokinetic and preclinical studies were excluded. Data Synthesis: In chronic and episodic migraine, prophylaxis with injections of monoclonal antibodies antagonizing CGRP reduced monthly migraine days with minimal clinically significant adverse events. In addition, there is evidence supporting efficacy in refractory migraine despite optimal prophylaxis. Relevance to Patient Care and Clinical Practice: This is the first target-specific migraine prophylaxis treatment to show efficacy with minimal adverse effects. A higher drug cost is a barrier but is balanced by improved quality of life. Current therapies have limited efficacy and tolerability because of poor side effect profiles. CGRP antagonists represent a shift to more precise migraine treatments. Conclusions: Monoclonal antibodies inhibiting CGRP are effective in migraine prophylaxis with minimal adverse effects. Targeting CGRP is a novel clinical strategy in managing migraine.

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.

Familial "Diplegic" Migraine - Description of a Family With a Novel CACNA1A Mutation

OBJECTIVE

To characterize phenotypes of a novel CACNA1A mutation causing familial hemiplegic migraine type 1.

BACKGROUND

Familial hemiplegic migraine is a rare monogenic form of migraine associated with attacks of fully reversible unilateral motor weakness. We now report a novel CACNA1A gene mutation associated with fully reversible bilateral motor weakness (diplegia).

METHODS

The proband underwent genotyping which identified a novel CACNA1A missense mutation (c.622 [isoform 1] G > A [p.Gly208Arg]). To characterize phenotypes associated with this novel mutation, the proband and 8 of her similarly affected family members underwent a semi-structured interview.

RESULTS

All 9 subjects who were interviewed met ICHD-3 phenotypic diagnostic criteria for FHM, including reporting attacks with reversible unilateral motor weakness. Additionally, 7 of 9 subjects reported attacks including reversible motor weakness affecting both sides of the body simultaneously.

CONCLUSIONS

We describe a novel CACNA1A mutation associated with migraine attacks including reversible diplegia.

Assessment Of Spanlastic Vesicles Of Zolmitriptan For Treating Migraine In Rats

OBJECTIVE

To develop and evaluate zolmitriptan spanlastics (Zol SLs) as a brain-targeted antimigraine delivery system. Spanlastics (SLs) prepared using span 60: tween 80 (70:30%, respectively) gave the highest percentage of entrapment efficiency (EE%).

MATERIALS AND METHODS

A total of 60 adult male Wistar albino rats were divided into six groups (n=10 rats/group). Group 1 (Control) comprised rats serving as a negative control. Group 2 was treated with glyceryl trinitrate (NTG) and served as the positive control. Groups 3 (NTG+Zol com), Group 4 (NTG+Zol sol) and Group 5 (NTG+Zol SLs) received commercial zolmitriptan orally, zolmitriptan solution intranasally and Zol SLs F5 intranasally, respectively, 30 min before NTG. Group 6 (Zol SLs) comprised normal rats that received only Zol SLs intranasally.

RESULTS

We found decreased Tmax, increased Cmax, AUC0-6, AUC0-∞ and ameliorated behaviour in rats (head scratching) treated with intranasal SLs compared to oral commercial zolmitriptan.

CONCLUSION

Our study substantiates the enhanced efficacy of Zol SLs in brain targeting for migraine treatment.

Interictal Hyperperfusion in the Higher Visual Cortex in Patients With Episodic Migraine

BACKGROUND

Migraine pathophysiology is complex and probably involves cortical and subcortical alterations. Structural and functional brain imaging studies indicate alterations in the higher order visual cortex in patients with migraine. Arterial spin labeling magnetic resonance imaging (ASL-MRI) is a non-invasive imaging method for assessing changes in cerebral blood flow (CBF) in vivo.

OBJECTIVE

To examine if interictal CBF differs between patients with episodic migraine (EM) with or without aura and healthy controls (HC).

METHODS

We assessed interictal CBF using 2D pseudo-continuous ASL-MRI on a 3 Tesla Philips scanner (University Hospital Zurich, Switzerland) in EM (N = 17, mean age 32.7 ± 9.9, 13 females) and HC (N = 19, mean age 31.0 ± 9.3, 11 females).

RESULTS

Compared to HC, EM showed exclusively hyperperfusion in the right MT+ and Cohen's d effect size was 0.99 (HC mean CBF ± SD: 33.1 ± 5.9 mL/100 g/minutes; EM mean CBF: 40.9 ± 9.4 mL/100 g/minutes). EM with aura (N = 13, MwA) revealed hyperperfusion compared to HC in the right MT+ and superior temporal gyrus. For MT, Cohen's d effect size was 1.34 (HC mean CBF ± SD: 33.1 ± 5.9 mL/100 g/minutes; MwA mean CBF: 43.3 ± 8.6 mL/100 g/minutes). For the superior temporal gyrus, Cohen's d effect size was 1.28 (HC mean CBF ± SD: 40.1 ± 4.9 mL/100 g/minutes; MwA mean CBF: 47.4 ± 6.4 mL/100 g/minutes). In EM, anxiety was positively associated with CBF in the parietal operculum and angular gyrus.

CONCLUSIONS

Our results suggest that extrastriate brain regions probably involved in cortical spreading depression are associated with CBF changes in the interictal state. We conclude that ASL-MRI is a sensitive method to identify local neuro-functional abnormalities in CBF in patients with EM in the interictal state.

Paranasal sinus air suction for immediate pain relief of acute migraine - a randomized, double blind pilot study

Background

Migraine is a primary headache disorder, which cause significant disability in adolescence. This double blind, randomized clinical trial assessed the immediate effects of suction of paranasal sinus air during an acute migraine episode.

Methods

A randomized, double blind study was conducted with 56 selected Sri Lankan school children of 16–19 years of age. Participants who met International Headache Society criteria for migraine (with or without aura) were included in the study. Subjects were randomly allocated into 2 groups where one group was subjected to three intermittent 10 sec paranasal air suctions with a ten sec suction free interval between two suctions for each nostril and the other group was subjected to placebo air suction (no paranasal air suction) in similar arrangement. Severity of headache and sub–orbital tenderness before and after suction were recorded using standard pain rating scale.

Results

After dropouts, treated and placebo groups consisted of 27 and 23 subjects respectively. The mean headache pain score drop in the treated group was significantly higher compared to that of the control group. Moreover, there was a difference in the treatment response between the types of headache (with or without aura). With respect to tenderness there was a statistically significant drop in the treated group compared to the control. In general, airflow rates in left and right nostrils were different in these subjects. However such difference was not seen in the tenderness on two sides. Nevertheless it was revealed that airflow rate has a slight negative correlation with the tenderness irrespective of the side.

Conclusion

Sixty–second paranasal air suction can provide an immediate pain relief for acute migraine in adolescents. We did not assess pain outcomes beyond 60 s, but the initial responses suggests the need to further study the efficacy of paranasal suction in migraine. A further study is suggested to evaluate the acute effects, efficacy and side effects of paranasal air suction using follow up over a prolong period.

Trial registration

Sri Lanka Clinical Trials Registry SLCTR/2017/018, 29 Jun 2017. Retrospectively registered.

Botulinum toxin injections to cranial sutures for chronic migraine Rewinding the technique using ultrasound imaging

The treatment of chronic migraine headache is quite challenging and new alternatives are still being explored for its management. Onabotulinum toxin A (BoNT-A) applied into extracranial muscles has been shown to inhibit the release of acetylcholine and local nociceptive peptides at the sensory nerve endings. As the highest concentration of extracranial pain fibers are located at/nearby the sutures, extracranial applications of BoTN-A are suggested to be performed to sutures rather than into the head and neck muscles in the treatment of chronic migraine. Moreover, in an animal study, BoTN-A is found to be more effective for decreasing the chemosensitivity of meningeal nociceptors when the total dose is injected along the sutures in comparison to being divided into sutures and cranial muscles. Of note, since BoNT-A injections performed with the blind/nontargeted technique have lower effectivity and several complications (muscle weakness, ptosis, facial paresis, etc.), the use of ultrasound guidance for targeting the cranial sutures is definitely expected to provide technical ease, better pain relief and toxin tolerance in chronic migraine.

PD-L1 and PD-1 expressed in trigeminal ganglia may inhibit pain in an acute migraine model

BACKGROUND

Neurogenic inflammation, mediated by the activation of primary neurons, is thought to be an important factor in migraine pathophysiology. Programmed cell death ligand-1 (PD-L1) can suppress the immune response through the Programmed cell death-1 receptor. However, the role of PD-L1/PD-1 in migraine remains unclear. In this study we evaluated the expression and role of PD-L1/PD-1 in the trigeminal ganglia in an animal model of acute migraine.

METHODS

Acute nitroglycerin induces acute mechanical hyperalgesia that can be used as a readout of migraine-like pain. We investigated the expression of PD-L1 and PD-1 in the trigeminal ganglia in a mouse model by means of immunofluorescence labeling, quantitative reverse transcription-polymerase chain reaction and western blotting. We explored the effects of PD-1 in a migraine model by the von Frey test and by analyzing the expression of calcitonin gene-related peptide, interleukin-1β (IL-1β), interleukin-18 (IL-18), Tumor Necrosis Factor-α (TNF-α), interleukin-6 (IL-6) and transient receptor potential vanilloid (TRPV4) after the intravenous injection of a PD-1 inhibitor.

RESULTS

PD-L1 and PD-1 immunoreactivity were present in healthy trigeminal ganglia neurons. The mRNA levels of PD-L1 and PD-1 were significantly elevated 2 h, 4 h and 6 h after acute nitroglycerin treatment (p < 0.05). The protein levels of PD-L1 were significantly increased 2 h, 4 h and 6 h after treatment, and PD-1 was significantly increased at 2 h and 6 h. The blockade of PD-1 increased acute nitroglycerin-induced hyperalgesia, and this effect was accompanied by a more significant increase in calcitonin gene-related peptide, IL-1β, TNF-α, IL-6 and IL-18 in the trigeminal ganglia.

CONCLUSION

These findings suggest that PD-L1 and PD-1 might inhibit migraine-like pain by downregulating CGRP and inflammatory factors in the trigeminal ganglia. The use of PD-L1 and PD-1 as analgesics should be further studied.

Validation of antibody-based tools for galanin research

Antibodies are an integral biomedical tool, not only for research but also as therapeutic agents. However, progress can only be made with sensitive and specific antibodies. The regulatory (neuro)peptide galanin and its three endogenous receptors (GAL_1-3-R) are widely distributed in the central and peripheral nervous systems, and in peripheral non-neuronal tissues. The galanin system has multiple biological functions, including feeding behavior, pain processing, nerve regeneration and inflammation, to name only a few. Galanin could serve as biomarker in these processes, and therefore its receptors are potential drug targets for various diseases. For that reason, it is of paramount interest to precisely measure galanin peptide levels in tissues and to determine the cellular and subcellular localization of galanin receptors. A plethora of antibodies and antibody-based tools, including radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) kits, are commercially available to detect galanin and its receptors. However, many of them lack rigorous validation which casts doubt on their specificity. A goal of the present study was to raise awareness of the importance of validation of antibodies and antibody-based tools, with a specific focus on the galanin system. To that end, we tested and report here about commercially available antibodies against galanin and galanin receptors that appear specific to us. Furthermore, we investigated the validity of commercially available galanin ELISA kits. As the tested ELISAs failed to meet the validation requirements, we developed and validated a specific sandwich ELISA which can be used to detect full-length galanin in human plasma.

Clinical correlates of mathematical modeling of cortical spreading depression: Single-cases study

INTRODUCTION

Considerable connections between migraine with aura and cortical spreading depression (CSD), a depolarization wave originating in the visual cortex and traveling toward the frontal lobe, lead to the hypothesis that CSD is underlying migraine aura. The highly individual and complex characteristics of the brain cortex suggest that the geometry might impact the propagation of cortical spreading depression.

METHODS

In a single-case study, we simulated the CSD propagation for five migraine with aura patients, matching their symptoms during a migraine attack to the CSD wavefront propagation. This CSD wavefront was simulated on a patient-specific triangulated cortical mesh obtained from individual MRI imaging and personalized diffusivity tensors derived locally from diffusion tensor imaging data.

RESULTS

The CSD wave propagation was simulated on both hemispheres, despite in all but one patient the symptoms were attributable to one hemisphere. The CSD wave diffused with a large wavefront toward somatosensory and prefrontal regions, devoted to pain processing.

DISCUSSION

This case-control study suggests that the cortical geometry may contribute to the modality of CSD evolution and partly to clinical expression of aura symptoms. The simulated CSD is a large and diffuse phenomenon, possibly capable to activate trigeminal nociceptors and to involve cortical areas devoted to pain processing.

Migraine Genetic Variants Influence Cerebral Blood Flow

Objective

To investigate the association of migraine genetic variants with cerebral blood flow (CBF).

Background

Migraine is a common disorder with many genetic and non‐genetic factors affecting its occurrence. The exact pathophysiological mechanisms underlying the disease remain unclear, but are known to involve hemodynamic and vascular disruptions. Recent genome‐wide association studies have identified 44 genetic variants in 38 genetic loci that affect the risk of migraine, which provide the opportunity to further disentangle these mechanisms.

Methods

We included 4665 participants of the population‐based Rotterdam Study (mean age 65.0 ± 10.9 years, 55.6% women). Cross‐sectional area (mm²), flow velocity (mm/s), and blood flow (mL/min) were measured in both carotids and the basilar artery using 2‐dimensional phase‐contrast magnetic resonance imaging. We analyzed 43 previously identified migraine variants separately and calculated a genetic risk score (GRS). To assess the association with CBF, we used linear regression models adjusted for age, sex, and total brain volume. Hierarchical clustering was performed based on the associations with CBF measures and tissue enrichment.

Results

The rs67338227 risk allele was associated with higher flow velocity and smaller cross‐sectional area in the carotids (P_minimum = 3.7 × 10⁻⁸). Other variants were related to CBF with opposite directions of effect, but not significantly after multiple testing adjustments (P < 1.4 × 10⁻⁴). The migraine GRS was not associated with CBF after multiple testing corrections. Migraine risk variants were found to be enriched for flow in the basilar artery (λ = 2.39).

Conclusions

These findings show that genetic migraine risk is complexly associated with alterations in cerebral hemodynamics.

Gain-of-function mutations in the UNC-2/CaV2α channel lead to excitation-dominant synaptic transmission in Caenorhabditis elegans

Mutations in pre-synaptic voltage-gated calcium channels can lead to familial hemiplegic migraine type 1 (FHM1). While mammalian studies indicate that the migraine brain is hyperexcitable due to enhanced excitation or reduced inhibition, the molecular and cellular mechanisms underlying this excitatory/inhibitory (E/I) imbalance are poorly understood. We identified a gain-of-function (gf) mutation in the Caenorhabditis elegans CaV2 channel α1 subunit, UNC-2, which leads to increased calcium currents. unc-2(zf35gf) mutants exhibit hyperactivity and seizure-like motor behaviors. Expression of the unc-2 gene with FHM1 substitutions R192Q and S218L leads to hyperactivity similar to that of unc-2(zf35gf) mutants. unc-2(zf35gf) mutants display increased cholinergic and decreased GABAergic transmission. Moreover, increased cholinergic transmission in unc-2(zf35gf) mutants leads to an increase of cholinergic synapses and a TAX-6/calcineurin-dependent reduction of GABA synapses. Our studies reveal mechanisms through which CaV2 gain-of-function mutations disrupt excitation-inhibition balance in the nervous system.

Electrical stimulation of the superior sagittal sinus suppresses A-type K+ currents and increases P/Q- and T-type Ca2+ currents in rat trigeminal ganglion neurons

BACKGROUND

Migraine is a debilitating neurological disorder involving abnormal trigeminovascular activation and sensitization. However, the underlying cellular and molecular mechanisms remain unclear.

METHODS

A rat model of conscious migraine was established through the electrical stimulation (ES) of the dural mater surrounding the superior sagittal sinus. Using patch clamp recording, immunofluorescent labelling, enzyme-linked immunosorbent assays and western blot analysis, we studied the effects of ES on sensory neuronal excitability and elucidated the underlying mechanisms mediated by voltage-gated ion channels.

RESULTS

The calcitonin gene-related peptide (CGRP) level in the jugular vein blood and the number of CGRP-positive neurons in the trigeminal ganglia (TGs) were significantly increased in rats with ES-induced migraine. The application of ES increased actional potential firing in both small-sized IB₄-negative (IB₄^-) and IB₄⁺ TG neurons. No significant changes in voltage-gated Na⁺ currents were observed in the ES-treated groups. ES robustly suppressed the transient outward K⁺ current (I_A) in both types of TG neurons, while the delayed rectifier K⁺ current remained unchanged. Immunoblot analysis revealed that the protein expression of Kv4.3 was significantly decreased in the ES-treated groups, while Kv1.4 remained unaffected. Interestingly, ES increased the P/Q-type and T-type Ca²⁺ currents in small-sized IB₄^- TG neurons, while there were no significant changes in the IB₄⁺ subpopulation of neurons.

CONCLUSION

These results suggest that ES decreases the I_A in small-sized TG neurons and increases P/Q- and T-type Ca²⁺ currents in the IB₄^- subpopulation of TG neurons, which might contribute to neuronal hyperexcitability in a rat model of ES-induced migraine.