Brain activations in the premonitory phase of nitroglycerin-triggered migraine attacks

Advances in understanding migraine for the development of novel pharmacotherapies: the use of human provocation migraine models

INTRODUCTION

Whilst migraine treatment has advanced significantly over recent times, the mechanisms of attack genesis and heterogeneity in treatment response are two amidst several areas that remain poorly understood and require further development. Experimental migraine provocation is an area that holds promise in advancing this understanding.

AREAS COVERED

We conducted a literature search using PubMed, of 'human migraine triggering' and 'human migraine provocation' to identify articles of interest. We discuss therapeutic targets that have emerged from such work, including calcitonin family peptides (amylin (AMY) and adrenomedullin (ADM)), pituitary adenylate cyclase-activating peptide (PACAP) and potassium channels. We discuss our views on the clinical translation of the outcomes of such studies, and their previous and potential future impact on migraine therapeutics.

EXPERT OPINION

Migraine provocation models provide a valuable means to study human migraine phenotypically and biologically, as well as to assess treatment response. Downstream intracellular mechanisms of provocation agents can be targeted during cellular processing to alter cell function and influence migraine mechanisms. It is important to caveat the clinical translation of provocation studies, given that just because a substance triggers migraine experimentally, does not necessarily mean that the substance is involved in the spontaneous human condition.

The role and interaction of hypothalamic-related neurotransmitters in migraine

Migraine is a complex neurological disorder frequently associated with hypothalamic dysfunction. This brain region is essential for maintaining homeostasis due to its regulation of autonomic, endocrine, and circadian systems. While the pathophysiology of migraine remains incompletely understood, clinical features such as the cyclic nature of attacks and symptoms, including nausea, vomiting, yawning, irritability, and sensitivity to light, indicate a significant role for the hypothalamus. Further, potential triggers of migraine, such as stress and disruption to feeding habits, also impact hypothalamic mechanisms. The higher prevalence of migraine in women compared to men suggests a link to hormonal fluctuations involving estrogen, progesterone, and prolactin. These hormones interact with the hypothalamus, potentially influencing the onset and severity of migraine episodes. Additionally, the hypothalamus synthesizes neuropeptides such as orexins, neuropeptide Y, PACAP, oxytocin, and vasopressin, which are all implicated in migraine mechanisms. Understanding the interplay between the hypothalamus, sex hormones, and neuropeptides offers valuable opportunities for endogenous targeted migraine therapies. In this review we discuss hypothalamic contributions to migraine pathophysiology, highlighting the mechanisms affected by hypothalamic connections, neuropeptides, and hormones, and their role as migraine triggers, particularly focusing on factors like stress, fasting, and changes in sleep patterns.

Ubrogepant for the treatment of migraine prodromal symptoms: an exploratory analysis from the randomized phase 3 PRODROME trial

PRODROME was a phase 3, placebo-controlled, double-blind crossover trial evaluating whether ubrogepant 100 mg, a calcitonin gene-related peptide receptor antagonist, dosed during the premonitory (prodromal) phase of migraine, prevented development of headache and resolved prodromal symptoms. Qualifying prodromal events were defined as attacks with symptoms in which the participant was confident headache would follow within 1-6 h. Of 1,087 screened participants, 477 formed the efficacy analysis population. Outcomes were collected across 48 h showing, for example, at 2 h post-dose, absence of photophobia in 19.5% and 12.5% of ubrogepant- and placebo-treated events, respectively (odds ratio (OR) = 1.72 (95% confidence interval (CI) = 1.13-2.61)); at 3 h post-dose, absence of fatigue occurred in 27.3% and 16.8% (OR = 1.85 (95% CI = 1.17-2.92)) and absence of neck pain in 28.9% and 15.9% (OR = 2.04 (95% CI = 1.25-3.32)) of events; at 4 h post-dose, absence of phonophobia in 50.7% and 35.8% (OR = 1.97 (95% CI = 1.38-2.80)) of events; and at 24 h post-dose, absence of dizziness in 88.5% and 82.3% (OR = 1.82 (95% CI = 1.00-3.30)) of events. At 1 h and 6 h post-dose, respectively, absence of difficulty concentrating occurred in 8.7% and 2.1% (OR = 4.26 (95% CI = 1.17-15.54)) and absence of difficulty thinking occurred in 56.9% and 41.8% (OR = 2.05 (95% CI = 1.14-3.71)) of events. Treatment with ubrogepant during the prodromal phase may ameliorate common prodromal symptoms, with improvements possibly as early as 1 h post-dose.

Hypothalamic connectivity strength is decreasing with polygenic risk in migraine without aura patients

Migraine is a heritable primary headache disorder which pathophysiology involves altered hypothalamic activity during migraine attacks. To explore the relationship between hypothalamic functional connectivity (HYPT FC) and genetic predisposition characterised by polygenic risk scores (PRS), in migraine, this research examines two types of PRS: one based on all migraine patients (PRSALL) regardless of their time of diagnosis and other disorders, and another on migraine-first patients (PRSFIRST), whose first diagnosed condition was migraine in their lifetime. In an independent sample of 35 migraine patients and 38 healthy controls, using resting-state functional magnetic resonance (rfMRI, 3T) brain imaging, the study reveals significant hypoconnectivity of hypothalamus with the two investigated PRS scores but with different brain areas. While weakened hypothalamic connections in relations with PRSALL highlight regions involved in pain modulation, correlation with PRSFIRST emphasizes decreased connections with sensory and integrative brain areas, suggesting a link between migraine-first genetic risk and cortical hyperexcitability. Our results demonstrate that the polygenic risk of different migraine subgroups may advance our insight into the specific genetic and neural underpinnings of migraine, advancing precision medicine approaches in this field.

High-risk area for migraine attacks - a new concept in migraine pathophysiology

Migraine is a common primary and often disabling neurological disorder, whose pathophysiology is still debated. It does not appear to be an isolated event of head pain but the consequence of recurrent disruption of healthy homeostasis in some brain functions. We propose a new theoretical model, focused on the existence of a "high-risk area" for migraine attacks, which can represent a potential target of non-pharmacologic treatment and prevention. We suggest that migraine arises from the combined effects of three primary factors, namely depressive or unstable mood, unrestful sleep and sympathetic-parasympathetic imbalance with parasympathetic prevalence, alongside with their temporal variability, potentially through dysfunction of homeostatic hypothalamic networks in susceptible individuals. Moreover, these three primary factors contribute to a state of low brain energy, that contains the high-risk area and represents the condition in which migraine attacks rise up. Wearable devices, self-administered questionnaires and clinical tools (i.e., polysomnography, pupillary light reflex, plasma catecholamines dosage) may be used to monitor autonomic nervous system function, mood and sleep and demonstrate the existence of the high-risk area. This will be helpful for patients to understand when they are about to enter in the high-risk area, in order to implement strategies to prevent migraine attacks. This approach would provide a significant advantage in terms of prevention and early treatment.

Evaluation of premonitory spontaneous and nitroglycerin triggered symptoms among patients with cluster headache and migraine

BackgroundOur knowledge of the presence and type of premonitory symptoms in patients with cluster headache is limited.MethodsPremonitory symptom presence and type in a clinical cohort of cluster headache and migraine was collated retrospectively from clinical notes, alongside a cluster headache nitroglycerin triggered experimental group and an age-matched migraine nitroglycerin experimental group. Demographic data and premonitory symptoms in cluster headache and migraine patients were analysed. The primary focus was on premonitory symptom presence and phenotype in cluster headache patients, with secondary analysis exploring associated factors and comparing spontaneous and nitroglycerin-triggered symptoms in cluster headache and migraine cohorts.ResultsAmong 164 cluster headache patients, 122/164 (74%) males, aged 45.9 ± 13.8 years (mean ± SD), 66/164 (40%) had chronic cluster headache and 32/164 (20%) had also comorbid migraine. Among them, 85% exhibited premonitory symptoms for which the presence was associated with oxygen treatment. No significant differences were found in symptom frequency between cluster headache and migraine cohorts or within spontaneous and nitroglycerin-triggered symptoms.ConclusionsThis study highlights recognizable spontaneous and nitroglycerin-triggered premonitory symptoms in cluster headache and factors potentially impacting cluster headache management, which may aid in tailoring treatment strategies for both conditions through the use of treatment prediction and early intervention.

Effects of acute sleep deprivation on the brain function of individuals with migraine: a resting-state functional magnetic resonance imaging study

BACKGROUND

Sleep deprivation can trigger acute headache attacks in individuals with migraine; however, the underlying mechanism remains poorly understood. The aim of this study was to investigate the effects of acute sleep deprivation (ASD) on brain function in individuals with migraine without aura (MWoA) via functional magnetic resonance imaging (fMRI).

METHODS

Twenty three MWoA individuals and 23 healthy controls (HCs) were fairly included in this study. All participants underwent two MRI scans: one at baseline (prior to sleep deprivation) and another following 24 h of ASD. Images were obtained with blood-oxygen-level-dependent and T1-weighted sequences on a Siemens 7.0 T MRI scanner. We conducted analyses of changes in the low-frequency fluctuations (ALFF) values and functional connectivity (FC) between brain networks and within network before and after ASD in both MWoA group and HC group. Additionally, we investigated the relationship between the changes in ALFF before and after ASD and the clinical features (VAS and monthly headache days).

RESULTS

In the HC group, ASD led to a significant increase in ALFF values in the left parahippocampal gyrus compared to baseline (p-FDR = 0.01). In the MWoA group, ALFF values were significantly greater in 64 brain regions after ASD than at baseline. The most significant change in ALFF before and after ASD in the MWoA group was detected in the right medial pulvinar of the thalamus (p-FDR = 0.017), which showed a significant negative correlation with monthly headache days. Moreover, seed-based connectivity (SBC) analysis using the right medial pulvinar of the thalamus as the seed point revealed significantly increased connectivity with the cerebellar vermis (p-FWE = 0.035) after ASD in individuals with MWoA, whereas connectivity with the right postcentral gyrus was significantly decreased (p-FWE = 0.048). Furthermore, we performed analyses of between-network connectivity (BNC) and within-network connectivity across 17 brain networks, utilizing the Yeo-17 atlas. Both MWoA individuals and HCs showed no significant changes in BNC after ASD compared to baseline. However, our analysis in within-network revealed that MWoA individuals exhibited a reduced within-network FC in dorsal attention network (DAN) after ASD compared to baseline (p-FDR = 0.031), whereas HCs showed no significant differences in within-network FC across all networks before and after ASD.

CONCLUSIONS

In comparison to HCs, MWoA individuals exhibited significant alterations in brain function after ASD, particularly within the thalamus, and MWoA individuals exhibited a reduced within-network FC in DAN after ASD compared to baseline. Brain regions and networks in MWoA individuals were more susceptible to the effects of ASD.

Treating episodic migraine with precision: the evolving landscape of targeted therapies driven by insights in disease biology

INTRODUCTION

Migraine is a disabling neurological disorder with a complex neurobiology. It appears as a cyclic disorder of sensory processing, affecting multiple systems beyond nociception. Overlapping mechanisms, including dysfunctional processing of sensory input from brain structures are involved in the generation of attacks.

AREAS COVERED

This review provides a comprehensive synthesis on migraine neurobiology, which was additionally informed by search of research databases (PubMed, ClinicalTrials.gov). Findings from the most recent literature are integrated in a pathophysiological framework. By combining mechanistic insights and clinical trial data, this review highlights the trajectory of precision medicine in migraine treatment, offering a perspective on the near future of targeted and individualized therapeutic strategies.

EXPERT OPINION

Recent advances in migraine neurobiology offer potential solutions to longstanding challenges. While targeted CGRP therapies have shown promise by addressing specific mechanisms, the pathophysiology of migraine suggests that combination therapies targeting multiple pathways could be beneficial in migraine prevention. The growing diversity of treatment options presents challenges in therapy selection, underscoring the need for predictive biomarkers. These innovations can optimize treatment strategies and improve patient outcomes. As the field progresses, personalized, multimodal approaches are poised to become the standard of care, significantly advancing precision medicine in this area.

A narrative review of autophagy in migraine

Background and objective

Autophagy is a natural process regulated by autophagy-related genes in eukaryotic cells that involves the degradation of cytoplasmic proteins and old or damaged organelles via the lysosomal pathway to help maintain cell homeostasis. Previous studies have suggested a potential association between autophagy and migraine, while the underlying mechanisms remain unclear. This review seeks to evaluate the possible involvement of autophagy in the pathophysiology of migraine, aiming to clarify its role and implications for future research and therapeutic strategies.

Methods

A search in PubMed was conducted for English-language articles until December 5, 2024. Key terms of "autophagy," "migraine," "microglia," "neurogenic inflammation," "central sensitization," "mitophagy" and "neuropathic pain" in different combinations.

Results

In the context of migraine, the activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB/Akt) signaling pathway exerts a direct influence on the mammalian target of rapamycin (mTOR), leading to a reduction in autophagy levels. Moreover, the stimulation of purinergic ligand-gated ion channel type 7 receptor (P2X7R) in microglia can hinder autophagy by interfering with the fusion of autophagosomes and lysosomes, which impedes the degradation of substrates within the autophagolysosome. Increased levels of calcitonin gene-related peptide (CGRP) may also modulate autophagy through the Akt/mTOR or protein kinase A (PKA)/mTOR signaling pathways. Additionally, research indicates that mitophagy may be partially impaired in individuals suffering from migraine. Furthermore, autophagy could contribute to the dysregulation of synaptic plasticity by influencing the processes of long-term potentiation (LTP) and long-term depression (LTD), both of which are associated with central sensitization in chronic migraine.

Conclusion

These findings suggest that autophagy may play an important role in the pathophysiology of migraine, particularly in its development and central sensitization. Research on autophagy modulators related to migraine will provide valuable insights for treatment strategies.

Brain connectivity in individuals with migraine resets during the headache phase: a whole-brain connectivity study

Episodic migraine is reflected by cyclic changes in behavior and cortical processing. We aimed to identify how functional connectivity changes over the entire migraine cycle. By using longitudinal neuroimaging and a whole-brain connectivity analysis approach, we tested 12 episodic migraine patients across 82 functional MRI recordings during spontaneous migraine headaches with follow-up measurements over the pain-free interval without any external stimulation. We found that the functional connectivity linearly increased over the interictal interval. In the prodromal phase, we observed the strongest connections between the anterior agranular insula and the posterior orbitofrontal cortex with sensory, motor and cingulate areas. The strength of the connections dropped during the headache. Peak connectivity during the prodromal phase and its collapse during the headache can be regarded as a mechanism of normalizing cortical processing. We speculate about a malfunction at the molecular level in agranular frontal and insular regions, which needs to be addressed in subsequent studies.

Region-specific changes in brain glutamate and gamma-aminobutyric acid across the migraine attack in children and adolescents

ABSTRACT

In patients with migraine, an excitation-inhibition imbalance that fluctuates relative to attack onset has been proposed to contribute to the underlying pathophysiology of migraine, but this has yet to be explored in children and adolescents. This prospective, observational, cohort study examined glutamate and gamma-aminobutyric acid (GABA) levels across the phases of a migraine attack and interictally in children and adolescents using magnetic resonance spectroscopy. Macromolecule-suppressed GABA (sensorimotor cortex and thalamus) and glutamate (occipital cortex, sensorimotor cortex, and thalamus) were measured in children and adolescents (10-17 years) with a migraine diagnosis with or without aura 4 times over 2 weeks. Linear mixed-effects models examined changes in glutamate and GABA during the 72 hours leading up to, and after the onset of an attack. We found significant region-specific changes in glutamate and GABA. Specifically, sensorimotor GABA significantly increased leading up to the headache phase, whereas glutamate significantly decreased following the headache onset in the occipital cortex and the thalamus. Post hoc analyses examined the 24 hours leading up to or following the onset of the headache phase. In the 24 hours before the headache onset, sensorimotor glutamate, occipital glutamate, and thalamic GABA decreased. In the 24 hours post headache onset, sensorimotor glutamate continued to decrease. Our results suggest changes in glutamate and GABA that are consistent with the thalamocortical dysrhythmia hypothesis. These findings provide insight into developmental migraine pathophysiology and may open future avenues for treatment targets specific to children and adolescents.

Treatment of migraine with aura with osteopathic manipulative treatment: a case report with renewed perspectives

Migraines make up a significant number of office visits every year, yet their pathophysiology and etiology remain largely elusive. This case report presents a 33-year-old patient who originally presented to the emergency department (ED) as a stroke alert and was later determined to have migraine with aura. The patient experienced an acute onset of headache, dizziness, and new-onset expressive aphasia. Before administration of a migraine cocktail, osteopathic manipulative treatment (OMT) was performed and was able to fully resolve all of her symptoms. In an effort to explain the outcomes in this case, a review of the current literature was performed, which provides an interesting perspective on the interplay of the musculoskeletal system and neuroanatomy. The literature establishes that somatic dysfunctions in the cervical vertebrae and trapezius may play a role in migraines and provide rationale for the use of OMT.

Transcriptomic changes in the hypothalamus of mice with chronic migraine: Activation of pathways associated with neuropathic inflammation and central sensitization

Chronic migraine is a common central nervous system disorder characterized by recurrent, pulsating headaches. However, the extent and mechanisms of hypothalamic involvement in disease progression have not been thoroughly investigated. Herein, we created a chronic migraine mouse model using repeated intraperitoneal injections of nitroglycerin. We performed transcriptomic sequencing on the hypothalamus of mice with chronic migraine and control mice under normal physiological conditions, followed by differential gene set enrichment and functional analysis of the data. Additionally, we examined the intrinsic connection between chronic migraine and sleep disorders using transcriptomic sequencing data from sleep-deprived mice available in public databases. We identified 39 differentially expressed genes (DEGs) in the hypothalamus of a mouse model of chronic migraine. Functional analysis of DEGs revealed enrichment primarily in signaling transduction, immune-inflammatory responses, and the cellular microenvironment. A comparison of the transcriptomic data of sleep-deprived mice revealed two commonly expressed DEGs. Our findings indicate that the hypothalamic DEGs are primarily enriched in the PI3K/AKT/mTOR pathway and associated with the NF-κB/NLRP3/IL-1 β pathway activation to maintain the central sensitization of the chronic migraine. Chronic migraine-induced gene expression changes in the hypothalamus may help better understand the underlying mechanisms and identify therapeutic targets.

The prodrome of migraine: mechanistic insights and emerging therapeutic strategies

Migraine is a common clinical chronic neurovascular disease characterized by recurrent, mostly unilateral, moderate or severe, pulsatile headache. It can be divided into four clinical stages: premonitory (prodrome), aura, headache and postdrome. The early warning value of the prodrome in migraine has been largely verified in various studies. In fact, the prodrome of migraine has received increasing attention as it can serve as an ideal therapeutic window for early intervention and effective treatment of migraine. In recent years, the pathophysiological and molecular biological mechanisms in the prodromal stage of migraine have been extensively studied, and great progress has been made in understanding the disease. This review paper aims to provide an overview of recent studies mainly focused on the prodrome of migraine, discuss the biological mechanisms underlying the clinical profile, and reveal novel therapeutic strategies for preventing or blocking migraine onset during its prodrome.

Association between brain resting-state functional activities and migraine: a bidirectional mendelian randomization study

Researchers have conducted extensive research on the correlation between brain resting-state functional activities (RSFA) and migraine. However, we still do not fully understand the exact nature of the causal relationship between these RSFA and migraine. We conducted a bidirectional two-sample Mendelian randomization (MR) study to investigate the causal association between migraine and RSFA. We gathered summary statistics from genome-wide association studies for 191 resting-state functional magnetic resonance imaging phenotypes. We employed various analytical methods for bidirectional two-sample MR analyses. This included inverse variance weighted, weighted median, MR Egger, and the constrained maximum likelihood approaches. We also conducted pleiotropy and heterogeneity analyses to evaluate the robustness and reliability. We found the functional connectivity between the default mode and the central executive network (OR = 1.39, p = 4.77 × 10-4, FDR corrected p value = 0.040) and the intensity of spontaneous brain activity in the calcarine or lingual gyrus within the visual network (OR = 0.74, p = 5.94 × 10-4, FDR corrected p value = 0.040) having a causal effect on the risk of migraine. Our MR analysis provided genetic support for these networks, which may play an important role in influencing migraine susceptibility.

Pre-cluster symptoms in a Taiwanese cohort of cluster headache: symptom profiles and clinical predictions

BACKGROUND

Pre-cluster symptoms (PCSs) are symptoms preceding cluster bouts and might have implications for the treatment of cluster headache (CH). This study investigated the prevalence of PCSs, and their utility in predicting upcoming bouts as well as the associations with therapeutic efficacy.

METHODS

We prospectively collected data from patients with CH. Each patient received a structured interview and completed questionnaire surveys during CH bouts. In sub-study 1, we cross-sectionally analyzed the prevalence, symptomatology, and predictability of upcoming bouts. Overall, 34 PCSs, divided into seven categories, were queried, including head and neck pain, cranial autonomic symptoms, restlessness, fatigue or mood changes, sleep alterations, constitutional symptoms, and generalized pain. In sub-study 2, we recorded the weekly frequency of CH attacks after the initiation of verapamil concurrently with a 14-day transitional therapy based on the patients' headache diary. A responder to verapamil was defined as a patient who have a reduction from baseline of at least 50% in the weekly frequency of CH attacks 4 weeks after the initiation of verapamil.

RESULTS

A total of 168 CH patients (women/men: 39/129) completed the study. In sub-study 1, we found 149 (88.7%) experienced PCSs, with a median of 24 (IQR 18 to 72) hours before the bouts. Up to 57.7% of patients with PCS reported that they could predict upcoming bouts. Among the seven categories of PCSs, head and neck pain was the most common (81.0%) and was associated with a higher predictability of upcoming bouts (odds ratio [OR] = 4.0; 95% confidence interval [CI] 1.7-9.6). In sub-study 2, we found two categories of PCSs were associated with the response to verapamil: sleep alteration (OR = 2.5 [95% CI = 1.3-4.8], p = 0.004) and ≥ 1 cranial autonomic symptoms (OR = 2.7 [95% CI = 1.4-5.1], p = 0.003).

CONCLUSION

PCSs were very common in CH and could be used to predict upcoming bouts. Different symptom categories of PCSs may have different clinical implications.

Insights from triggers and prodromal symptoms on how migraine attacks start: The threshold hypothesis

BACKGROUND

The prodrome or premonitory phase is the initial phase of a migraine attack, and it is considered as a symptomatic phase in which prodromal symptoms may occur. There is evidence that attacks start 24-48 hours before the headache phase. Individuals with migraine also report several potential triggers for their attacks, which may be mistaken for premonitory symptoms and hinder migraine research.

METHODS

This review aims to summarize published studies that describe contributions to understanding the fine difference between prodromal/premonitory symptoms and triggers, give insights for research, and propose a way forward to study these phenomena. We finally aim to formulate a theory to unify migraine triggers and prodromal symptoms. For this purpose, a comprehensive narrative review of the published literature on clinical, neurophysiological and imaging evidence on migraine prodromal symptoms and triggers was conducted using the PubMed database.

RESULTS

Brain activity and network connectivity changes occur during the prodromal phase. These changes give rise to prodromal/premonitory symptoms in some individuals, which may be falsely interpreted as triggers at the same time as representing the early manifestation of the beginning of the attack. By contrast, certain migraine triggers, such as stress, hormone changes or sleep deprivation, acting as a catalyst in reducing the migraine threshold, might facilitate these changes and increase the chances of a migraine attack. Migraine triggers and prodromal/premonitory symptoms can be confused and have an intertwined relationship with the hypothalamus as the central hub for integrating external and internal body signals.

CONCLUSIONS

Differentiating migraine triggers and prodromal symptoms is crucial for shedding light on migraine pathophysiology and improve migraine management.

Calcitonin Gene-Related Peptide Inhibitors in the Treatment of Migraine in the Pediatric and Adolescent Populations: A Review

There are limited well-studied treatments for migraine in the pediatric population. Calcitonin gene-related peptide (CGRP) inhibitors are an established safe and effective treatment in adults, and use may be appropriate for pediatric patients in certain clinical situations. We describe migraine pathophysiology as it relates to CGRP, provide an overview of available medications, and discuss clinical usage in this population.

In search of a neuropsychological profile for migraine: A scoping review

OBJECTIVE

Migraine is commonly overlooked by the general population and by professionals in research and clinical practice. Moreover, it is difficult to grasp the neuropsychological profile of migraineurs due to the cyclic nature of the disorder. With this in mind, a scoping review of the literature was conducted with the goal of characterizing cognitive domains associated with deficits in migraine.

METHODS

PubMed, PsychInfo, Scopus, EMBASE and OpenGrey databases were searched for studies published from 1st January 2006 to 30th November 2022. Following the review process, 52 eligible studies were included in the review.

RESULTS

Studies included in this review show mixed and sometimes contradictory findings. Overall, both visual and auditory perception appear to be impaired. Deficits on attention, many memory processes, visuospatial function and spatial navigation and on a wide range of executive functions (set-shifting and cognitive flexibility, decision-making and reasoning, working memory and prospective memory) complete a complex cognitive profile in migraine. Lack of consistency across studies in sample selection and sizes, lack of detailed links between cognitive deficits and specific migraine phases, or length and chronicity, inconsistencies on the role of aura in cognitive function; and heterogeneity and sometimes questionable reliability and validity of some of the cognitive measures used may affect the clarity and consistency of results observed.

CONCLUSION

Further research properly addressing the role of gender and age, migraine stage, length and chronicity of the condition, the effect of aura and comorbidities is needed, alongside increasing consistency across diverse neuropsychological assessment protocols.

SIGNIFICANCE

This review provides a comprehensive, up-to-date picture of the current status of knowledge in relation to the characterization of the complex cognitive profile of migraine. It offers detailed information of the existing research gaps and challenges to improve the cognitive characterization of migraine across its different stages and leads clinicians to carefully consider the selection of relevant cognitive tasks, in order to grasp more accurately the patient's cognitive profile; an assessment that should be an integral part of any protocol developed for the clinical assessment and subsequent treatment planning for migraine.

The effect of P2X7 antagonism on subcortical spread of optogenetically-triggered cortical spreading depression and neuroinflammation

Migraine is a neurological disorder characterized by episodes of severe headache. Cortical spreading depression (CSD), the electrophysiological equivalent of migraine aura, results in opening of pannexin 1 megachannels that release ATP and triggers parenchymal neuroinflammatory signaling cascade in the cortex. Migraine symptoms suggesting subcortical dysfunction bring subcortical spread of CSD under the light. Here, we investigated the role of purinergic P2X7 receptors on the subcortical spread of CSD and its consequent neuroinflammation using a potent and selective P2X7R antagonist, JNJ-47965567. P2X7R antagonism had no effect on the CSD threshold and characteristics but increased the latency to hypothalamic voltage deflection following CSD suggesting that ATP acts as a mediator in the subcortical spread. P2X7R antagonism also prevented cortical and subcortical neuronal activation following CSD, revealed by bilateral decrease in c-fos positive neuron count, and halted CSD-induced neuroinflammation revealed by decreased neuronal HMGB1 release and decreased nuclear translocation of NF-kappa B-p65 in astrocytes. In conclusion, our data suggest that P2X7R plays a role in CSD-induced neuroinflammation, subcortical spread of CSD and CSD-induced neuronal activation hence can be a potential target.

Multi-omics Mendelian randomization integrating GWAS, eQTL and pQTL data revealed GSTM4 as a potential drug target for migraine

INTRODUCTION

Migraine, as a complex neurological disease, brings heavy burden to patients and society. Despite the availability of established therapies, existing medications have limited efficacy. Thus, we aimed to find the drug targets that improve the prognosis of migraine.

METHOD

We used Mendelian Randomization (MR) and Summary-data-based MR (SMR) analyses to study possible drug targets of migraine by summary statistics from FinnGen cohorts (nCase = 44,616, nControl = 367,565), with further replication in UK Biobank (nCase = 26,052, nControl = 487,214). Genetic instruments were obtained from eQTLGen and UKB-PPP to verify the drug targets at the gene expression and protein levels. The additional analyses including Bayesian co-localization, the heterogeneity in dependent instruments(HEIDI), Linkage Disequilibrium Score(LDSC), bidirectional MR, multivariate MR(MVMR), heterogeneity test, horizontal pleiotropy test, and Steiger filtering were implemented to consolidate the findings further. Lastly, drug prediction analysis and phenome-wide association study(PheWAS) were employed to imply the possibility of drug targets for future clinical applications.

RESULT

The MR analysis of eQTL data showed that four drug targets (PROCR, GSTM4, SLC4A1, and TNFRSF10A) were significantly associated with migraine risk in both the FinnGen and UK Biobank cohorts. However, only GSTM4 exhibited consistent effect directions across the two outcomes(Discovery cohort: OR(95%CI) = 0.94(0.93-0.96); p = 2.70e - 10; Replication cohort: OR(95%CI) = 0.93(0.91-0.94); p = 4.21e - 17). Furthermore, GSTM4 passed the SMR at p < 0.05 and HEIDI test at p > 0.05 at both the gene expression and protein levels. The protein-level MR analysis revealed a strong correlation between genetically predicted GSTM4 with a lower incidence of migraine and its subtypes(Overall migraine: OR(95%CI) = 0.91(0.87-0.95); p = 6.98e-05; Migraine with aura(MA): OR(95%CI) = 0.90(0.85-0.96); p = 2.54e-03; Migraine without aura(MO): OR(95%CI) = 0.90(0.83-0.96); p = 2.87e-03), indicating a strong co-localization relationship (PPH4 = 0.86). Further analyses provided additional validation for the possibility of GSTM4 as a migraine treatment target.

CONCLUSION

This study identifies GSTM4 as a potential druggable gene and promising therapeutic target for migraine.

Characterizing neck pain during headache among people with migraine: Multicountry results from the Chronic Migraine Epidemiology and Outcomes - International (CaMEO-I) cross-sectional study

OBJECTIVE

To assess the prevalence and impact of neck pain during headache among respondents with migraine in the multicountry Chronic Migraine Epidemiology and Outcomes - International (CaMEO-I) Study.

BACKGROUND

Neck pain among individuals with migraine is highly prevalent and contributes to disability.

METHODS

The CaMEO-I was a prospective, cross-sectional, web-based study conducted in Canada, France, Germany, Japan, United Kingdom, and the United States. A demographically representative sample of participants from each country completed a screening survey to evaluate headache characteristics. Respondents with headache were identified as having migraine or non-migraine headache based on modified International Classification of Headache Disorders, third edition, criteria; those with migraine completed a detailed survey with migraine-specific assessments. Results were stratified by the presence or absence of neck pain with headache (NPWH). For these analyses, data were pooled across the six countries.

RESULTS

Of 51,969 respondents who reported headache within the past 12 months, 14,492 (27.9%) were classified as having migraine; the remaining 37,477 (72.1%) had non-migraine headache. Overall, 9896/14,492 (68.3%) of respondents with migraine headache reported NPWH, which was significantly higher (p < 0.001) than the proportion of respondents with non-migraine headache who reported NPWH (13,536/37,477 [36.1%]). Among respondents with migraine, moderate-to-severe disability was significantly more prevalent for those with NPWH versus without (47.7% [4718/9896] vs. 28.9%, p < 0.001). Respondents with NPWH versus without also had significantly greater work productivity losses, at a median (interquartile range [IQR]) of 50.0 (20.0, 71.3) vs. 30.0 (0.0, 60.0) (p < 0.001), lower quality of life (Migraine-Specific Quality of Life questionnaire version 2.1, median [IQR] Role Function-Restrictive domain score 60.0 [42.9, 74.3] vs. 68.6 [54.3, 82.9], p < 0.001), higher prevalence of depression and anxiety symptoms (depression, 40.2% [3982/9896] vs. 28.2% [1296/4596], p < 0.001); anxiety, 41.2% [4082/9896] vs. 29.2% [1343/4596], p < 0.001), higher prevalence of cutaneous allodynia during headache (54.0% [5345/9896] vs. 36.6% [1681/4596], p < 0.001), and higher prevalence of poor acute treatment optimization (61.1% [5582/9129] vs. 53.3% [2197/4122], p < 0.001).

CONCLUSIONS

Nearly 70% of respondents with migraine reported NPWH. Individuals with migraine with neck pain during their headaches had greater disability, depression, anxiety, and cutaneous allodynia (during headache) than those without neck pain during their headaches. They also had diminished quality of life and work productivity, and poorer response to acute treatment compared with those without neck pain.

Pituitary cyclase-activating polypeptide targeted treatments for the treatment of primary headache disorders

OBJECTIVE

Migraine is a complex and disabling neurological disorder. Recent years have witnessed the development and emergence of novel treatments for the condition, namely those targeting calcitonin gene-related peptide (CGRP). However, there remains a substantial need for further treatments for those unresponsive to current therapies. Targeting pituitary adenylate cyclase-activating polypeptide (PACAP) as a possible therapeutic strategy in the primary headache disorders has gained interest over recent years.

METHODS

This review will summarize what we know about PACAP to date: its expression, receptors, roles in migraine and cluster headache biology, insights gained from preclinical and clinical models of migraine, and therapeutic scope.

RESULTS

PACAP shares homology with vasoactive intestinal polypeptide (VIP) and is one of several vasoactive neuropeptides along with CGRP and VIP, which has been implicated in migraine neurobiology. PACAP is widely expressed in areas of interest in migraine pathophysiology, such as the thalamus, trigeminal nucleus caudalis, and sphenopalatine ganglion. Preclinical evidence suggests a role for PACAP in trigeminovascular sensitization, while clinical evidence shows ictal release of PACAP in migraine and intravenous infusion of PACAP triggering attacks in susceptible individuals. PACAP leads to dural vasodilatation and secondary central phenomena via its binding to different G-protein-coupled receptors, and intracellular downstream effects through cyclic adenosine monophosphate (cAMP) and phosphokinase C (PKC). Targeting PACAP as a therapeutic strategy in headache has been explored using monoclonal antibodies developed against PACAP and against the PAC1 receptor, with initial positive results.

INTERPRETATION

Future clinical trials hold considerable promise for a new therapeutic approach using PACAP-targeted therapies in both migraine and cluster headache.

Intervening in the Premonitory Phase to Prevent Migraine: Prospects for Pharmacotherapy

Migraine is a common brain condition characterised by disabling attacks of headache with sensory sensitivities. Despite increasing understanding of migraine neurobiology and the impacts of this on therapeutic developments, there remains a need for treatment options for patients underserved by currently available therapies. The first specific drugs developed to treat migraine acutely, the serotonin-5-hydroxytryptamine [5-HT1B/1D] receptor agonists (triptans), seem to require headache onset in order to have an effect, while early treatment during mild pain before headache escalation improves short-term and long-term outcomes. Some patients find treating in the early window once headache has started but not escalated difficult, and migraine can arise from sleep or in the early hours of the morning, making prompt treatment after pain onset challenging. Triptans may be deemed unsuitable for use in patients with vascular disease and in those of older age and may not be effective in a proportion of patients. Headache is also increasingly recognised as being just one of the many facets of the migraine attack, and for some patients it is not the most disabling symptom. In many patients, painless symptoms can start prior to headache onset and can reliably warn of impending headache. There is, therefore, a need to identify therapeutic targets and agents that may be used as early as possible in the course of the attack, to prevent headache onset before it starts, and to reduce both headache and non-headache related attack burden. Early small studies using domperidone, naratriptan and dihydroergotamine have suggested that this approach could be useful; these studies were methodologically less rigorous than modern day treatment studies, of small sample size, and have not since been replicated. The emergence of novel targeted migraine treatments more recently, specifically calcitonin gene-related peptide (CGRP) receptor antagonists (gepants), has reignited interest in this strategy, with encouraging results. This review summarises historical and emerging data in this area, supporting use of the premonitory phase as an opportunity to intervene as early as possible in migraine to prevent attack-related morbidity.

Assessing the impact of migraine on benign paroxysmal positional vertigo symptoms and recovery

BACKGROUND

During episodes of benign paroxysmal positional vertigo (BPPV), individuals with migraine, compared with individuals without migraine, may experience more severe vestibular symptoms because of their hyperexcitable brain structures, more adverse effects on quality of life, and worse recovery processes from BPPV.

METHODS

All patients with BPPV were assigned to the migraine group (MG, n = 64) and without migraine group (BPPV w/o MG, n = 64) and completed the Vertigo Symptom Scale (VSS), Vertigo Dizziness Imbalance Symptom Scale (VDI-SS), VDI Health-Related Quality of Life Scale (VDI-HRQoLS), Beck Anxiety Inventory (BAI), and Beck Depression Inventory (BDI) at the time of BPPV diagnosis (baseline) and on the one-month follow-up. Headache Impact Test-6 and Migraine Disability Assessment Scale were used for an assessment of headache. Motion sickness was evaluated based on the statement of each patient as present or absent.

RESULTS

Compared with the BPPV w/o MG, the MG had higher VSS scores at baseline [19.5 (10.7) vs. 11.3 (8.5); p < 0.001] and on one-month follow-up [10.9 (9.3) vs. 2.2 (2.7), p < 0.001]; experienced more severe dizziness and imbalance symptoms based on the VDI-SS at baseline (61.9% vs. 77.3%; p < 0.001) and after one month (78.9% vs. 93.7%, p < 0.001); and more significantly impaired quality of life according to the VDI-HRQoLS at baseline (77.4% vs. 91.8%, p < 0.001) and after one month (86.3% vs. 97.6%, p < 0.001). On the one-month follow-up, the subgroups of patients with moderate and severe scores of the BAI were higher in the MG (39.2%, n = 24) than in the BPPV w/o MG (21.8%, n = 14) and the number of patients who had normal scores of the BDI was lower in the MG than in the BPPV w/o MG (67.1% vs. 87.5%, p = 0.038).

CONCLUSION

Clinicians are advised to inquire about migraine when evaluating patients with BPPV because it may lead to more intricate and severe clinical presentation. Further studies will be elaborated the genuine nature of the causal relationship between migraine and BPPV.

Orexins and primary headaches: an overview of the neurobiology and clinical impact

INTRODUCTION

Primary headaches, including migraines and cluster headaches, are highly prevalent disorders that significantly impact quality of life. Several factors suggest a key role for the hypothalamus, including neuroimaging studies, attack periodicity, and the presence of altered homeostatic regulation. The orexins are two neuropeptides synthesized almost exclusively in the lateral hypothalamus with widespread projections across the central nervous system. They are involved in an array of functions including homeostatic regulation and nociception, suggesting a potential role in primary headaches.

AREAS COVERED

This review summarizes current knowledge of the neurobiology of orexins, their involvement in sleep-wake regulation, nociception, and functions relevant to the associated symptomology of headache disorders. Preclinical reports of the antinociceptive effects of orexin-A in preclinical models are discussed, as well as clinical evidence for the potential involvement of the orexinergic system in headache.

EXPERT OPINION

Several lines of evidence support the targeted modulation of orexinergic signaling in primary headaches. Critically, orexins A and B, acting differentially via the orexin 1 and 2 receptors, respectively, demonstrate differential effects on trigeminal pain processing, indicating why dual-receptor antagonists failed to show clinical efficacy. The authors propose that orexin 1 receptor agonists or positive allosteric modulators should be the focus of future research.

Research hotspots and frontiers of cluster headaches: a bibliometric analysis

Background

Extensive research on cluster headaches (CHs) has been conducted worldwide; however, there is currently no bibliometric research on CHs. Therefore, this study aimed to analyze the current research hotspots and frontiers of CHs over the past decade.

Methods

Raw data on CHs was obtained from the Web of Science Core Collection database from 2014 to 2023. CiteSpace V6.2 R7 (64 bit) and Microsoft Excel were used to assess the annual publication volume, authors, countries, and references. VOSviewer 1.6.19 software was used to assess the institutions, cited authors, and keywords, and co-occurrence and clustering functions were applied to draw a visual knowledge map.

Results

In the past decade, the overall annual publication volume of articles related to CHs has increased year by year, showing promising development prospects. The total 1909 articles contained six types of literature, among which the proportion of original research articles was the highest (1,270 articles, 66.53%), published in 201 journals. Cephalalgia (439 articles, 23.00%) had the highest publication volume, and the Lancet was the journal with the highest impact factor (IF = 168.9). Furthermore, the United States of America was the country with the most published papers (584 articles, 30.60%), University of London was the research institution with the most published papers (142 articles, 7.44%), and Goodsby, Peter J was found to be the most prolific author (38 articles, 1.99%).

Conclusion

This study may provide some direction for subsequent researcher on CHs. The hotspots and frontiers of future research on CHs are suggested as follows: in basic medicine, more attention should be paid to pathophysiology, especially on increasing research on the pathogenesis mediated by CGRP; in clinical medicine, more attention should be paid to the design of evidence-based medicine methodology, especially the strict design, including double-blind, questionnaire, and follow-up, in randomized controlled trials, using high-quality articles for meta-analyses, and recommending high-level evidence; therapeutic techniques need to be further explored, suggesting the implementation of transcranial magnetic stimulation of the cortex, and stimulation of the sphinopalatine ganglia and occipital nerve to achieve peripheral neuromodulation. Furthermore, chronic migraine and insomnia are inextricably linked to CHs.

Medication "underuse" headache

BACKGROUND

Many risk factors have been associated with migraine progression, including insufficient and ineffective utilization of migraine medications; however, they have been inadequately explored. This has resulted in suboptimal usage of medications without effective altering of prescribing recommendations for patients, posing a risk for migraine chronification.

METHODS

Our aim is to conduct a comprehensive review of the available evidence regarding the underuse of migraine medications, both acute and preventive. The term "underuse" includes, but is not limited to: (1) ineffective use of appropriate and inappropriate medication; (2) underutilization; (3) inappropriate timing of usage; and (4) patient dissatisfaction with medication.

RESULTS

The underuse of both acute and preventive medications has been shown to contribute to the progression of migraine. In terms of acute medication, chronification occurs as a result of insufficient drug use, including failure of the prescriber to select the appropriate type based on pain intensity and disability, patients taking medication too late (more than 60 minutes after the onset or after central sensitization has occurred as evidenced by allodynia), and discontinuation because of lack of effect or intolerable side effects. The underlying cause of inadequate effectiveness of acute medication lies in its inability to halt the propagation of peripheral activation to central sensitization in a timely manner. For oral and injectable preventive migraine medications, insufficient efficacy and intolerable side effects have led to poor adherence and discontinuation with subsequent progression of migraine. The underlying pathophysiology here is rooted in the repetitive stimulation of afferent sensory pain fibers, followed by ascending brainstem pain pathways plus dysfunction of the endogenous descending brainstem pain inhibitory pathway. Although anti-calcitonin gene-related peptide (CGRP) medications partially address pain caused by the above factors, including decreased efficacy and tolerability from conventional therapy, some patients do not respond well to this treatment. Research suggests that initiating preventive anti-CGRP treatment at an early stage (during low frequency episodic migraine attacks) is more beneficial than commencing it during high frequency episodic attacks or when chronic migraine has begun.

CONCLUSIONS

The term "medication underuse" is underrecognized, but it holds significant importance. Optimal usage of acute care and preventive migraine medications could potentially prevent migraine chronification and improve the treatment of migraine attacks.

Pathophysiology of Migraine

OBJECTIVE

This article provides an overview of the current understanding of migraine pathophysiology through insights gained from the extended symptom spectrum of migraine, neuroanatomy, migraine neurochemistry, and therapeutics.

LATEST DEVELOPMENTS

Recent advances in human migraine research, including human experimental migraine models and functional neuroimaging, have provided novel insights into migraine attack initiation, neurochemistry, neuroanatomy, and therapeutic substrates. It has become clear that migraine is a neural disorder, in which a wide range of brain areas and neurochemical systems are implicated, producing a heterogeneous clinical phenotype. Many of these neural pathways are monoaminergic and peptidergic, such as those involving calcitonin gene-related peptide and pituitary adenylate cyclase-activating polypeptide. We are currently witnessing an exciting era in which specific drugs targeting these pathways have shown promise in treating migraine, including some studies suggesting efficacy before headache has even started.

ESSENTIAL POINTS

Migraine is a brain disorder involving both headache and altered sensory, limbic, and homeostatic processing. A complex interplay between neurotransmitter systems, physiologic systems, and pain processing likely occurs. Targeting various therapeutic substrates within these networks provides an exciting avenue for future migraine therapeutics.

Models of Trigeminal Activation: Is There an Animal Model of Migraine?

Migraine, recognized as a severe headache disorder, is widely prevalent, significantly impacting the quality of life for those affected. This article aims to provide a comprehensive review of the application of animal model technologies in unraveling the pathomechanism of migraine and developing more effective therapies. It introduces a variety of animal experimental models used in migraine research, emphasizing their versatility and importance in simulating various aspects of the condition. It details the benefits arising from the utilization of these models, emphasizing their role in elucidating pain mechanisms, clarifying trigeminal activation, as well as replicating migraine symptoms and histological changes. In addition, the article consciously acknowledges the inherent limitations and challenges associated with the application of animal experimental models. Recognizing these constraints is a fundamental step toward fine-tuning and optimizing the models for a more accurate reflection of and translatability to the human environment. Overall, a detailed and comprehensive understanding of migraine animal models is crucial for navigating the complexity of the disease. These findings not only provide a deeper insight into the multifaceted nature of migraine but also serve as a foundation for developing effective therapeutic strategies that specifically address the unique challenges arising from migraine pathology.

How early can we treat migraine attacks? A perspective based on prodrome

Treating migraine attacks early at the onset of a headache is a common proven strategy. But does this strategy work before headache onset? In the PRODROME trial, Dodick et al. showed that ubrogepant taken during the prodrome can prevent headache attacks and reduce functional disability.1.

Astrocytic Na+, K+ ATPases in physiology and pathophysiology

The Na+, K+ ATPases play a fundamental role in the homeostatic functions of astrocytes. After a brief historic prologue and discussion of the subunit composition and localization of the astrocytic Na+, K+ ATPases, the review focuses on the role of the astrocytic Na+, K+ pumps in extracellular K+ and glutamate homeostasis, intracellular Na+ and Ca2+ homeostasis and signaling, regulation of synaptic transmission and neurometabolic coupling between astrocytes and neurons. Loss-of-function mutations in the gene encoding the astrocytic α2 Na+, K+ ATPase cause a rare monogenic form of migraine with aura (familial hemiplegic migraine type 2). On the other hand, the α2 Na+, K+ ATPase is upregulated in spinal cord and brain samples from amyotrophic lateral sclerosis and Alzheimer disease patients, respectively. In the last part, the review focuses on i) the migraine relevant phenotypes shown by familial hemiplegic migraine type 2 knock-in mice with 50 % reduced expression of the astrocytic α2 Na+, K+ ATPase and the insights into the pathophysiology of migraine obtained from these genetic mouse models, and ii) the evidence that upregulation of the astrocytic α2 Na+, K+ ATPase in mouse models of amyotrophic lateral sclerosis and Alzheimer disease promotes neuroinflammation and contributes to progressive neurodegeneration.

Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

Migraine as an allostatic reset triggered by unresolved interoceptive prediction errors

Until now, a satisfying account of the cause and purpose of migraine has remained elusive. We explain migraine within the frameworks of allostasis (the situationally-flexible, forward-looking equivalent of homeostasis) and active inference (interacting with the environment via internally-generated predictions). Due to its multimodality, and long timescales between cause and effect, allostasis is inherently prone to catastrophic error, which might be impossible to correct once fully manifest, an early indicator which is elevated prediction error (discrepancy between prediction and sensory input) associated with internal sensations (interoception). Errors can usually be resolved in a targeted manner by action (correcting the physiological state) or perception (updating predictions in light of sensory input); persistent errors are amplified broadly and multimodally, to prioritise their resolution (the migraine premonitory phase); finally, if still unresolved, progressive amplification renders further changes to internal or external sensory inputs intolerably intense, enforcing physiological stability, and facilitating accurate allostatic prediction updating. As such, migraine is an effective 'failsafe' for allostasis, however it has potential to become excessively triggered, therefore maladaptive.

Nine-Month Continuous Fremanezumab Prophylaxis on the Response to Triptans and Also on the Incidence of Triggers, Hypersensitivity and Prodromal Symptoms of Patients with High-Frequency Episodic Migraine

Objective: To investigate whether the incidence of triggers, prodromal symptoms, hypersensitivity symptoms accompanying headache and responses to triptans were modified during a continuous 9-month fremanezumab therapy for migraine prophylaxis. Patients and methods: We studied 63 patients with high-frequency episodic migraine (HFEM). Enrolled patients received fremanezumab for nine consecutive months before defining the response rates and being stratified into treatment responders (≥50-74% reduction in monthly headache days (MHDs)), super responders (≥75%), partial non-responders (<50%) and super non-responders (<30%). Through headache diaries, patients provided data in order to document the impact of fremanezumab on the incidence of triggers, associated symptoms followed by headache and response to triptans (the use of the migraine treatment optimization questionnaire-4 (mTOQ-4)) during the 9-month treatment period. Results: Fremanezumab had early (after 3 monthly cycles) beneficial effects on the response to triptans in the majority of responders with relevant increases in mTOQ-4 scoring, but also in half of partial non-responders. A significant reduction in median days with migraine-associated symptoms was seen in responders after 6 months of therapy with fremanezumab, mostly for osmophobia, photophobia, phonophobia and nausea/vomiting, but partial non-responders also benefited. Likewise, the incidence of self-reported prodromal symptoms was significantly reduced in responders and was modestly diminished in partial non-responders. Triggers remained unaffected in both responders and non-responders. Conclusions: Fremanezumab given for at least 6-9 months may exert neuromodulatory effects in the migraine brain. These effects could result both in the inhibition of migraine chronification, but also in the diminishing of the magnitude of migraine-associated symptoms, mostly in responders and in partial non-responders.

In Search of More Leaps to Realize the Precision Medicine of Migraine

Migraine, clinically characterized by recurrent headache attacks of moderate-to-severe intensity, is the second most disabling disease in terms of years lived with disability [...].

The evolutionary meaning of migraine

INTRODUCTION

Migraine's astonishing prevalence and preserved genetic background contrast with the definition of a disease and the biological meaning of experiencing recurrent, severe headache attacks is still puzzling.

METHODS

To provide a comprehensive explanation of the migraine evolutionary meaning, we review (i) the putative role of the autonomic nervous system in migraine attacks, (ii) the inter-ictal autonomic, functional, and metabolic signature of migraine patients, (iii) the bio-behavioral perspective of pain, and (iv) the allostatic perception of migraine chronification.

RESULTS

Migraineurs have inter-ictal cortical hyperexcitability and metabolic dysfunction that predisposes to brain energetic imbalance. Multiple precipitating factors may lead to brain energy consumption over the migraine attack generation threshold. In response, the brain engenders adaptive, evolutionary conserved, autonomic-behavior responses through the antidromic activation of the trigeminovascular system. The sickness behavior and severe pain experienced during migraine attacks result in avoiding mental and physical activity, allowing brain energy restoration. Chronic exposure to stressors may result in an allostatic overload, leading to maladaptive chronic activation of these responses. In this bio-behavioral perspective, the chronification of migraine should be envisioned as a pathological process, whereas the migraine itself should not.

CONCLUSION

Migraine has an evolutionary (Darwinian) meaning.

Multimodal Migraine Management and the Pursuit of Migraine Freedom: A Narrative Review

Migraine is a neurologic disease with a complex pathophysiology that can be controlled with current treatment options but not cured. Therefore, treatment expectations are highly variable. The concept of migraine freedom was recently introduced and can mean different things, with some, for example, expecting complete freedom from headache and associated symptoms and others accepting the occasional migraine attack if it does not impact functioning. Therefore, migraine management should be optimized so that patients can have the best opportunity to achieve their optimal treatment goals. With migraine freedom as a goal and, given the complex pathophysiology of migraine and the high incidence of comorbidities among individuals with migraine, treatment with a single modality may be insufficient, as it may not achieve migraine freedom in those with more frequent or disabling attacks. In this clinical perspective article, we have identified four key, partially overlapping principles of multimodal migraine treatment: (1) manage common comorbidities; (2) control modifiable risk factors for progression by addressing medication and caffeine overuse; (3) diagnose and treat secondary causes of headache, if present; and (4) individualize acute and preventive treatments to minimize pain, functional disability, and allodynia. There are many barriers to pursuing migraine freedom, and strategies to overcome them should be optimized. Migraine freedom should be an aspirational goal both at the individual attack level and for the disease overall. We believe that a comprehensive and multimodal approach that addresses all barriers people with migraine face could move patients closer to migraine freedom.

Central generators of migraine and autonomic cephalalgias as targets for personalized pain management: Translational links

BACKGROUND AND OBJECTIVE

Migraine oscillates between different states in association with internal homeostatic functions and biological rhythms that become more easily dysregulated in genetically susceptible individuals. Clinical and pre-clinical data on migraine pathophysiology support a primary role of the central nervous system (CNS) through 'dysexcitability' of certain brain networks, and a critical contribution of the peripheral sensory and autonomic signalling from the intracranial meningeal innervation. This review focuses on the most relevant back and forward translational studies devoted to the assessment of CNS dysfunctions involved in primary headaches and discusses the role they play in rendering the brain susceptible to headache states.

METHODS AND RESULTS

We collected a body of scientific literature from human and animal investigations that provide a compelling perspective on the anatomical and functional underpinnings of the CNS in migraine and trigeminal autonomic cephalalgias. We focus on medullary, hypothalamic and corticofugal modulation mechanisms that represent strategic neural substrates for elucidating the links between trigeminovascular maladaptive states, migraine triggering and the temporal phenotype of the disease.

CONCLUSION

It is argued that a better understanding of homeostatic dysfunctional states appears fundamental and may benefit the development of personalized therapeutic approaches for improving clinical outcomes in primary headache disorders.

SIGNIFICANCE

This review focuses on the most relevant back and forward translational studies showing the crucial role of top-down brain modulation in triggering and maintaining primary headache states and how these central dysfunctions may interact with personalized pain management strategies.

Aura phenomena do not initiate migraine attacks-Findings from neuroimaging

OBJECTIVES/BACKGROUND

As cortical spreading depolarization (CSD) has been suggested to be the cause of migraine aura and as CSD can activate trigeminal nociceptive neurons in animals, it has been suggested that CSD may be the cause of migraine attacks. This raises the question of how migraine pain is generated in migraine attacks without aura and has led to the hypothesis that CSD may also occur in subcortical regions in the form of "silent" CSDs, and accordingly "silent auras".

METHODS

In this case study, we provide evidence for common neuronal alterations preceding headache attacks with and without aura in a male patient with migraine, who underwent daily event-correlated functional magnetic resonance imaging of trigeminal nociception for a period of 30 days. During these days the man experienced migraine attacks with and without aura.

RESULTS

Comparing the preictal phases between both attack types revealed a common hyperactivation of the hypothalamus (p < 0.01), which was already present 2 days before the actual attack.

CONCLUSION

The time frame of the central pathophysiological orchestration of migraine attacks, irrelevant of the presence of later aura, strongly suggests that the aura is an epiphenomenon that is unrelated and does not initiate headache attacks.

Insights into migraine attacks from neuroimaging

Migraine is one of the most common neurological diseases and it has a huge social and personal impact. Although head pain is the core symptom, individuals with migraine can have a plethora of non-headache symptoms that precede, accompany, or follow the pain. Neuroimaging studies have shown that the involvement of specific brain areas can explain many of the symptoms reported during the different phases of migraine. Recruitment of the hypothalamus, pons, spinal trigeminal nucleus, thalamus, and visual and pain-processing cortical areas starts during the premonitory phase and persists through the headache phase, contributing to the onset of pain and associated symptoms. Once the pain stops, the involvement of most brain areas ends, although the pons, hypothalamus, and visual cortex remain active after acute treatment intake and resolution of migraine symptoms. A better understanding of the correlations between imaging findings and migraine symptomatology can provide new insight into migraine pathophysiology and the mechanisms of novel migraine-specific treatments.

Migraine: Advances in the Pathogenesis and Treatment

This article presents a comprehensive review on migraine, a prevalent neurological disorder characterized by chronic headaches, by focusing on their pathogenesis and treatment advances. By examining molecular markers and leveraging imaging techniques, the research identifies key mechanisms and triggers in migraine pathology, thereby improving our understanding of its pathophysiology. Special emphasis is given to the role of calcitonin gene-related peptide (CGRP) in migraine development. CGRP not only contributes to symptoms but also represents a promising therapeutic target, with inhibitors showing effectiveness in migraine management. The article further explores traditional medical treatments, scrutinizing the mechanisms, benefits, and limitations of commonly prescribed medications. This provides a segue into an analysis of emerging therapeutic strategies and their potential to enhance migraine management. Finally, the paper delves into neuromodulation as an innovative treatment modality. Clinical studies indicating its effectiveness in migraine management are reviewed, and the advantages and limitations of this technique are discussed. In summary, the article aims to enhance the understanding of migraine pathogenesis and present novel therapeutic possibilities that could revolutionize patient care.

Occipital transcranial direct current stimulation in episodic migraine patients: effect on cerebral perfusion

Cerebral blood flow differs between migraine patients and healthy controls during attack and the interictal period. This study compares the brain perfusion of episodic migraine patients and healthy controls and investigates the influence of anodal transcranial direct current stimulation (tDCS) over the occipital cortex. We included healthy adult controls and episodic migraineurs. After a 28-day baseline period and the baseline visit, migraine patients received daily active or sham anodal tDCS over the occipital lobe for 28 days. All participants underwent a MRI scan at baseline; migraineurs were also scanned shortly after the stimulation period and about five months later. At baseline, brain perfusion of migraine patients and controls differed in several areas; among the stimulated areas, perfusion was increased in the cuneus of healthy controls. At the first visit, the active tDCS group had an increased blood flow in regions processing visual stimuli and a decreased perfusion in other areas. Perfusion did not differ at the second follow-up visit. The lower perfusion level in migraineurs in the cuneus indicates a lower preactivation level. Anodal tDCS over the occipital cortex increases perfusion of several areas shortly after the stimulation period, but not 5 months later. An increase in the cortical preactivation level could mediate the transient reduction of the migraine frequency.Trial registration: NCT03237754 (registered at clincicaltrials.gov; full date of first trial registration: 03/08/2017).

Neuroimaging in the pre-ictal or premonitory phase of migraine: a narrative review

BACKGROUND

The premonitory phase, or prodrome, of migraine, provides valuable opportunities to study attack initiation and for treating the attack before headache starts. Much that has been learned about this phase in recent times has come from the outcomes of functional imaging studies. This review will summarise these studies to date and use their results to provide some feasible insights into migraine neurobiology.

MAIN BODY

The ability to scan repeatedly a patient without radiation and with non-invasive imaging modalities, as well as the recognition that human experimental migraine provocation compounds, such as nitroglycerin (NTG) and pituitary adenylate cyclase activating polypeptide (PACAP), can trigger typical premonitory symptoms (PS) and migraine-like headache in patients with migraine, have allowed feasible and reproducible imaging of the premonitory phase using NTG. Some studies have used serial scanning of patients with migraine to image the migraine cycle, including the 'pre-ictal' phase, defined by timing to headache onset rather than symptom phenotype. Direct observation and functional neuroimaging of triggered PS have also revealed compatible neural substrates for PS in the absence of headache. Various imaging methods including resting state functional MRI (rsfMRI), arterial spin labelling (ASL), positron emission tomography (PET) and diffusion tensor imaging (DTI) have been used. The results of imaging the spontaneous and triggered premonitory phase have been largely consistent and support a theory of central migraine attack initiation involving brain areas such as the hypothalamus, midbrain and limbic system. Early dysfunctional pain, sensory, limbic and homeostatic processing via monoaminergic and peptidergic neurotransmission likely manifests in the heterogeneous PS phenotype.

CONCLUSION

Advances in human migraine research, including the use of functional imaging techniques lacking radiation or radio-isotope exposure, have led to an exciting opportunity to study the premonitory phase using repeated measures imaging designs. These studies have provided novel insights into attack initiation, migraine neurochemistry and therapeutic targets. Emerging migraine-specific therapies, such as those targeting calcitonin gene-related peptide (CGRP), are showing promise acutely when taken during premonitory phase to reduce symptoms and prevent subsequent headache. Therapeutic research in this area using PS for headache onset prediction and early treatment is likely to grow in the future.

Molecular Mechanisms of Migraine: Nitric Oxide Synthase and Neuropeptides

Migraine is a common condition with disabling attacks that burdens people in the prime of their working lives. Despite years of research into migraine pathophysiology and therapeutics, much remains to be learned about the mechanisms at play in this complex neurovascular condition. Additionally, there remains a relative paucity of specific and targeted therapies available. Many sufferers remain underserved by currently available broad action preventive strategies, which are also complicated by poor tolerance and adverse effects. The development of preclinical migraine models in the laboratory, and the advances in human experimental migraine provocation, have led to the identification of key molecules likely involved in the molecular circuity of migraine, and have provided novel therapeutic targets. Importantly, the identification that vasoconstriction is neither necessary nor required for headache abortion has changed the landscape of migraine treatment and has broadened the therapy targets for patients with vascular risk factors or vascular disease. These targets include nitric oxide synthase (NOS) and several neuropeptides that are involved in migraine. The ability of NO donors and infusion of some of these peptides into humans to trigger typical migraine-like attacks has supported the development of targeted therapies against these molecules. Some of these, such as those targeting calcitonin gene-related peptide (CGRP), have already reached clinical practice and are displaying a positive outcome in migraineurs for the better by offering targeted efficacy without significant adverse effects. Others, such as those targeting pituitary adenylate cyclase activating polypeptide (PACAP), are showing promise and are likely to enter phase 3 clinical trials in the near future. Understanding these nitrergic and peptidergic mechanisms in migraine and their interactions is likely to lead to further therapeutic strategies for migraine in the future.

The human NTG model of migraine in drug discovery and development

INTRODUCTION

Various triggers can originate a migraine attack. In healthy volunteers and patients with migraine, the nitroglycerin (NTG) provocation model induces a headache that resembles migraine in pain characteristics and vascular manifestations. This headache is reversible and treatable in monitored conditions, providing an opportunity to test novel antimigraine medications in early clinical development.

AREAS COVERED

This perspective covers the main characteristics and applications of the human NTG model of migraine with effective and ineffective antimigraine therapies.

EXPERT OPINION

The NTG model represents a potential de-risking strategy to test novel hypotheses for antimigraine mechanisms in humans. Considering previous studies conducted with effective and ineffective antimigraine therapies, the sensitivity of the model was 71% while the specificity was 100%. The probability that following an analgesic effect, that compound would truly be efficacious in individuals with migraine was 100%. Following a negative result, the probability that such compound would truly be ineffective in patients with individuals was 33%. A clinical trial testing the analgesic properties of novel compounds after a sublingual and/or intravenous NTG challenge in migraine patients may support a subsequent phase 2 trial for the treatment of migraine.

Regional cerebral perfusion during the premonitory phase of triggered migraine: A double-blind randomized placebo-controlled functional imaging study using pseudo-continuous arterial spin labeling

OBJECTIVE

To identify changes in regional cerebral blood flow (CBF) associated with premonitory symptoms (PS) of nitroglycerin (NTG)-triggered migraine attacks.

BACKGROUND

PS could provide insights into attack initiation and alterations in neuronal function prior to headache onset.

METHODS

We undertook a functional imaging study using a double-blind placebo-controlled randomized approach in patients with migraine who spontaneously experienced PS, and in whom PS and migraine-like headache could be induced by administration of NTG. All study visits took place in a dedicated clinical research facility housing a monitoring area with clinical beds next to a 3Tesla magnetic resonance imaging scanner. Fifty-three patients with migraine were enrolled; imaging on at least one triggered visit was obtained from 25 patients, with 21 patients completing the entire imaging protocol including a placebo visit. Whole brain CBF maps were acquired using 3D pseudo-continuous arterial spin labeling (3D pCASL).

RESULTS

The primary outcome was that patients with migraine not taking preventive treatment (n = 12) displayed significant increases in CBF in anterior cingulate cortex, caudate, midbrain, lentiform, amygdala and hippocampus (p < 0.05 family-wise error-corrected) during NTG-induced PS. A separate region of interest analysis revealed significant CBF increases in the region of the hypothalamus (p = 0.006, effect size 0.77). Post hoc analyses revealed significant reductions in CBF over the occipital cortices in participants with a history of migraine with underlying aura (n = 14).

CONCLUSIONS

We identified significant regional CBF changes associated with NTG-induced PS, consistent with other investigations and with novel findings, withstanding statistical comparison against placebo. These findings were not present in patients who continually took preventive medication. Additional findings were identified only in participants who experience migraine with aura. Understanding this biological and treatment-related heterogeneity is vital to evaluating functional imaging outcomes in migraine research.

Migraine: from pathophysiology to treatment

Migraine is an extremely disabling, common neurological disorder characterized by a complex neurobiology, involving a series of central and peripheral nervous system areas and networks. A growing increase in the understanding of migraine pathophysiology in recent years has facilitated translation of that knowledge into novel treatments, which are currently becoming available to patients in many parts of the world and are substantially changing the clinical approach to the disease. In the first part of this review, we will provide an up to date overview of migraine pathophysiology by analyzing the anatomy and function of the main regions involved in the disease, focusing on how these give rise to the plethora of symptoms characterizing the attacks and overall disease. The second part of the paper will discuss the novel therapeutic agents that have emerged for the treatment of migraine, including molecules targeting calcitonin gene-related peptide (gepants and monoclonal antibodies), serotonin 5-HT_1F receptor agonists (ditans) and non-invasive neuromodulation, as well as providing a brief overview of new evidence for classic migraine treatments.

Astrocytic Glutamate Transporters and Migraine

Glutamate levels and lifetime in the brain extracellular space are dinamically regulated by a family of Na⁺- and K⁺-dependent glutamate transporters, which thereby control numerous brain functions and play a role in numerous neurological and psychiatric diseases. Migraine is a neurological disorder characterized by recurrent attacks of typically throbbing and unilateral headache and by a global dysfunction in multisensory processing. Familial hemiplegic migraine type 2 (FHM2) is a rare monogenic form of migraine with aura caused by loss-of-function mutations in the α2 Na/K ATPase (α2NKA). In the adult brain, this pump is expressed almost exclusively in astrocytes where it is colocalized with glutamate transporters. Knockin mouse models of FHM2 (FHM2 mice) show a reduced density of glutamate transporters in perisynaptic astrocytic processes (mirroring the reduced expression of α2NKA) and a reduced rate of glutamate clearance at cortical synapses during neuronal activity and sensory stimulation. Here we review the migraine-relevant alterations produced by the astrocytic glutamate transport dysfunction in FHM2 mice and their underlying mechanisms, in particular regarding the enhanced brain susceptibility to cortical spreading depression (the phenomenon that underlies migraine aura and can also initiate the headache mechanisms) and the enhanced algesic response to a migraine trigger.