Chronic Migraine: An Update on Physiology, Imaging, and the Mechanism of Action of Two Available Pharmacologic Therapies

TLR2 Mediates Microglial Activation and Contributes to Central Sensitization in a Recurrent Nitroglycerin-induced Chronic Migraine Model

Central sensitization is an important pathophysiological mechanism underlying chronic migraine (CM). Previous studies have shown that microglial activation and subsequent inflammation in the trigeminal nucleus caudalis (TNC) contribute to central sensitization. Toll-like receptor 2 (TLR2) is a receptor expressed on the membrane of microglia and participates in central sensitization in inflammatory and chronic pain; however, its role in CM is unclear. Therefore, this study investigated TLR2 involvement in CM in detail. Mice treated with recurrent nitroglycerin (NTG) were used as a CM model. Hyperalgesia was assessed using a 50% paw mechanical threshold and a 50% periorbital threshold on a Von Frey filament pain meter. Western blotting and immunofluorescence analyses were used to detect the expression of TLR2, microglia, c-fos and CGRP in TNC. The expression of inflammatory factors (IL-6, IL-1β、 IL-10、TNF-α and IFN-β1) was detected using quantitative real-time polymerase chain reaction (qRT-PCR). A selective TLR2 antagonist (C29) was systematically administered to observe its effect on hyperalgesia, microglia activation and the expression of c-fos, CGRP and inflammatory factors. Recurrent administration of NTG resulted in acute and chronic hypersensitivity, accompanied by upregulation of TLR2 expression and microglial activation in TNC. C29 partially inhibited pain hypersensitivity. C29 suppressed microglial activation induced by NTG administration. Inhibition of TLR2 reduced the expression of c-fos and CGRP in TNC after NTG treatment. C29 inhibited the expression of inflammatory mediators in TNC. These data showed that microglial TLR2 plays a critical role in the pathogenesis of CM by regulating microglial activation in TNC.

Update on gepants for the treatment of chronic migraine

Chronic migraine (CM) is a profoundly debilitating condition that has detrimental clinical and social outcomes. Over the past two decades, novel small-molecule calcitonin gene-related peptide (CGRP) receptor antagonists, known as gepants, and CGRP monoclonal antibodies (mAbs) have been developed, ushering in a new era of migraine-specific treatment. In this review, we discuss the literature investigating the role of gepants for the treatment of CM. Numerous completed and ongoing clinical studies have conclusively demonstrated the safety, tolerability, and efficacy of several gepants for the acute treatment of migraine. However, preventive trials involving gepants have focused on patients with episodic migraine, with atogepant being the only gepant approved for CM prevention by the US Food and Drug Administration at the time of writing. Although some preliminary positive results have been reported, further research is still required to achieve additional advancements in the future. In summary, the effectiveness of gepants for treating individuals with CM are highly expected. This review highlights the development and current progress of gepants for the treatment of CM, focusing both on their role as acute abortive agents and preventive measures and on their concomitant use with other antimigraine medications, such as CGRP mAbs or triptans.

[Mental disorders, social and demographic characteristics of patients with chronic and episodic migraine]

OBJECTIVE

To compare socio-demographic, clinical and psychological characteristics and comorbid mental disorders in patients with chronic migraine (CM) and episodic migraine (EM).

MATERIAL AND METHODS

Eighty patients with migraine (40 with CM (16 men and 24 women, mean age 33.5±6.1 years) and 40 with EM (9 men and 31 women, mean age 31.4±5.7 years) were examined. All patients were interviewed and tested with psychometric methods. Socio-demographic and clinical-psychological characteristics were determined in all patients. The psychiatrist assessed the mental status of patients and diagnosed comorbid mental disorders according to the ICD-10 criteria.

RESULTS

Symptoms of depression, high levels of trait and state anxiety, and a tendency to emotional inadequacy of response were more common in CM patients than in EM patients (p<0.05). Mental disorders, predominantly of the anxiety-depressive spectrum, were more common in CM patients than EM patients (OR (95% CI)=2.54 (2.03 to 2.98, p<0.001). Seventy-five percent of CM patients had more than one psychiatric diagnosis, almost a quarter of CM patients had schizotypal disorder, which is significantly higher than in EM patients (OR (95% CI)=1.99; 1.03 to 2.42, p<0.001). There were more unmarried, single (without constant partner), unemployed, high-education patients in the CM group than in the EM group. The negative impact of headache on the daily activity of patients was significantly higher in the CM group than in the EM group (p<0.05).

CONCLUSION

Mental disorders and psychological features (anxiety, depression symptoms, a tendency to emotional inadequacy of response) are more common in CM patients than in EM patients. The presence of these factors may contribute to the chronification of migraine.

Risk factors for migraine disease progression: a narrative review for a patient-centered approach

BACKGROUND

In individuals with migraine, attacks may increase in frequency, severity, or both. Preventing migraine progression has emerged as a treatment goal in headache subspecialty practice, but there may be less awareness in general neurology or primary care settings where most people with migraine who seek treatment consult. Herein, we review the definition of and risk factors for migraine progression and consider strategies that could reduce its risk.

METHODS

A group of headache expert healthcare professionals, clinicians, and researchers reviewed published evidence documenting factors associated with increased or decreased rates of migraine progression and established expert opinions for disease management recommendations. Strength of evidence was rated as good, moderate, or based solely on expert opinion, using modified criteria for causation developed by AB Hill.

RESULTS

Migraine progression is commonly operationally defined as the transition from ≤ 15 to ≥ 15 monthly headache days among people with migraine; however, this does not necessarily constitute a fundamental change in migraine biology and other definitions should be considered. Established and theoretical key risk factors for migraine progression were categorized into five domains: migraine disease characteristics, treatment-related factors, comorbidities, lifestyle/exogenous factors, and demographic factors. Within these domains, good evidence supports the following risk factors: poorly optimized acute headache treatment, cutaneous allodynia, acute medication overuse, selected psychiatric symptoms, extra-cephalic chronic pain conditions, metabolism-related comorbidities, sleep disturbances, respiratory conditions, former/current high caffeine intake, physical inactivity, financial constraints, tobacco use, and personal triggers as risk factors. Protective actions that may mitigate migraine progression are sparsely investigated in published literature; our discussion of these factors is primarily based on expert opinion.

CONCLUSIONS

Recognizing risk factors for migraine progression will allow healthcare providers to suggest protective actions against migraine progression (Supplementary Fig. 1). Intervention studies are needed to weight the risk factors and test the clinical benefit of hypothesized mitigation strategies that emerge from epidemiological evidence.

A Descriptive Review of Medication-Overuse Headache: From Pathophysiology to the Comorbidities

PURPOSE OF REVIEW

Medication-overuse headache (MOH) is an important problem worldwide, with different areas of controversy regarding its entity. This article reviews the risk factors, comorbidities, pathophysiology, clinical presentation, effective management, and prognosis of MOH by summarizing and integrating the results and findings from previously performed more than 15,000 studies (from 2010 to 2023) available from the scientific database of the University Medical Library in the University Clinical Center of Niš, which aimed to investigate and define the complexity of this type of headache.

RECENT FINDING

It has been proposed that all acute migraine medications can lead to MOH, with differences in the propensity of different agents to cause the problem. Early data suggests that triptans and other painkillers used for the acute treatment of migraine may be an exception. Recent studies show that practitioners and the general public are still largely unaware of the problem of medication overuse and its damaging effects.

SUMMARY

Although it is likely that MOH does occur, restricting the number of acute medications is necessary to prevent it. It is also possible that increasing amounts of acute medications are simply a reflection of poorly controlled headaches rather than a cause. Further research needs to be developed to identify more precise mechanisms for effective MOH management and its evolution.

Treatment of chronic migraine with Botox (onabotulinumtoxinA): Development, insights, and impact

Chronic migraine (CM) is a neurological disease characterized by frequent migraine attacks that prevent affected individuals from performing daily activities of living, significantly diminish quality of life, and increase familial burden. Before onabotulinumtoxinA was approved for CM, there were few treatment options for these seriously disabled patients and none had regulatory approval. The terminology and recognition of CM evolved in parallel with the onabotulinumtoxinA clinical development program. Because there were no globally accepted classification criteria for CM when onabotulinumtoxinA was in development, the patient populations for the trials conducted by Allergan were determined by the Allergan migraine team in collaboration with headache scientists and clinicians. These trials and collaborations ultimately led to improvements in CM classifications. In 2010, onabotulinumtoxinA became the first medication and first biologic approved specifically to prevent headaches in patients with CM. Approval was based on 2 similarly designed phase 3, double-blind, randomized, placebo-controlled, multicenter clinical studies. Both studies showed significantly greater improvements in mean change from baseline in headache-day frequency in patients with CM receiving onabotulinumtoxinA compared with those receiving placebo. The safety and effectiveness of onabotulinumtoxinA have been established globally in >5000 patients with CM with or without medication overuse treated in clinical and observational studies. Benefits also include improvements in quality of life, fewer psychiatric comorbidities, and reduced healthcare resource utilization. Across studies, onabotulinumtoxinA was well tolerated; adverse events tended to be mild or moderate in severity and to decline over subsequent treatment cycles.

Characterization of the biochemical and behavioral effects of cannabidiol: implications for migraine

Cannabidiol (CBD) is the main pharmacologically active phytocannabinoid. CBD exerts an analgesic effect in several pain models, does not have side effects and has low toxicity. The data about CBD mechanisms of action in pain and its therapeutic potential in this area are limited. Here, we tested CBD effects in animal models specific for migraine. We assayed CBD distribution in plasma and in cranial areas related to migraine pain in male Sprague Dawley rats treated chronically (5 days). Successively, we tested CBD activity on the behavioral and biochemical effects induced in the acute and the chronic migraine animal models by nitroglycerin (NTG) administration. In the acute migraine model, rats received CBD (15 mg or 30 mg/kg, i.p) 3 h after NTG (10 mg/kg i.p.) or vehicle injection. In the chronic migraine model, rats were treated with CBD and NTG every other day over nine days with the following doses: CBD 30 mg/kg i.p., NTG 10 mg/kg i.p. We evaluated behavioral parameters with the open field and the orofacial formalin tests. We explored the fatty acid amide hydrolase gene expression, cytokines mRNA and protein levels in selected brain areas and CGRP serum level. CBD levels in the meninges, trigeminal ganglia, cervical spinal cord, medulla pons, and plasma were higher 1 h after the last treatment than after 24 h, suggesting that CBD penetrates but does not accumulate in these tissues. In the acute model, CBD significantly reduced NTG-induced trigeminal hyperalgesia and CGRP and cytokine mRNA levels in peripheral and central sites. In the chronic model, CBD caused a significant decrease in NTG-induced IL-6 protein levels in the medulla-pons, and trigeminal ganglion. It also reduced CGRP serum levels. By contrast, CBD did not modulate TNF-alpha protein levels and fatty acid amide hydrolase (FAAH) gene expression in any of investigated areas. In both experimental conditions, there was no modulation of anxiety, motor/exploratory behavior, or grooming. These findings show that CBD reaches brain areas involved in migraine pain after systemic administration. They also show for the first time that CBD modulates migraine-related nociceptive transmission, likely via a complex signaling mechanism involving different pathways.

Reduced cardiovagal baroreflex sensitivity is associated with postural orthostatic tachycardia syndrome (POTS) and pain chronification in patients with headache

Background

Non-cephalgic symptoms including orthostatic intolerance, fatigue, and cognitive impairment, are common in patients with chronic headache disorders and may result from alterations in the autonomic nervous system. However, little is known about the function of autonomic reflexes, which regulate cardiovascular homeostasis and cerebral perfusion in patients with headache.

Methods

Autonomic function testing data from patients with headache collected between January 2018 and April 2022 was retrospectively analyzed. Through review of EMR we determined headache pain chronicity and patient self-report of orthostatic intolerance, fatigue, and cognitive impairment. Composite Autonomic Severity Score (CASS), CASS subscale scores, and cardiovagal and adrenergic baroreflex sensitivities were used to quantify autonomic reflex dysfunction. Descriptive analyses (Mann-Whitney-U or χ2, as appropriate) determined associations between autonomic reflex dysfunction and POTS as well as chronic headache. Binomial logistic regression adjusted for age and sex. Spearman’s rank correlation determined the association between the total CASS score and the number of painless symptoms reported by each participant.

Results

We identified 34 patients meeting inclusion criteria, of whom there were 16 (47.0%) with orthostatic intolerance, 17 (50.0%) with fatigue, 11 (32.4%) with cognitive complaints, and 11 (32.4%) with Postural Orthostatic Tachycardia Syndrome (POTS). The majority of participants had migraine (n = 24, 70.6%), were female (n = 23, 67.6%) and had a chronic (&gt;15 headache days in a month) headache disorder (n = 26, 76.5%). Reduced cardiovagal baroreflex sensitivity (BRS-V) independently predicted chronic headache [aOR: 18.59 (1.16, 297.05), p = 0.039] and POTS [aOR: 5.78 (1.0, 32.5), p = 0.047]. The total CASS was correlated with the total number of non-painful features in the expected direction (r = 0.46, p = 0.007).

Conclusion

Abnormal autonomic reflexes may play an important role in pain chronification and the development of POTS in patients with headache.

Brainstem volume changes in myalgic encephalomyelitis/chronic fatigue syndrome and long COVID patients

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID patients have overlapping neurological, autonomic, pain, and post-exertional symptoms. We compared volumes of brainstem regions for 10 ME/CFS (CCC or ICC criteria), 8 long COVID (WHO Delphi consensus), and 10 healthy control (HC) subjects on 3D, T1-weighted MRI images acquired using sub-millimeter isotropic resolution using an ultra-high field strength of 7 Tesla. Group comparisons with HC detected significantly larger volumes in ME/CFS for pons (p = 0.004) and whole brainstem (p = 0.01), and in long COVID for pons (p = 0.003), superior cerebellar peduncle (p = 0.009), and whole brainstem (p = 0.005). No significant differences were found between ME/CFS and long COVID volumes. In ME/CFS, we detected positive correlations between the pons and whole brainstem volumes with "pain" and negative correlations between the midbrain and whole brainstem volumes with "breathing difficulty." In long COVID patients a strong negative relationship was detected between midbrain volume and "breathing difficulty." Our study demonstrated an abnormal brainstem volume in both ME/CFS and long COVID consistent with the overlapping symptoms.

Chronic migraine and medication overuse

Though clearly described as far back as the 17th century, chronic migraine has defied precise categorization and has continued to develop as an important diagnostic concept with significant societal impact. Worldwide prevalence is estimated to be between 1% and 3%, and these patients form a dynamic group cycling between chronic and episodic migraine. Theories of pathogenesis are developing supported by recent imaging and other findings. Of the many determinants of progression to chronic migraine, overuse of acute abortive headache medications may be one of the most important modifiable factors. Treatment strategies, in addition to educational measures, have included various preventive migraine medications such as topiramate, valproate, and onabotulinumtoxinA. CGRP monoclonal antibodies are efficacious for the management of chronic migraine both with and without medication overuse.

Medication-overuse headache: clinical profile and management strategies

Medication-overuse headache (MOH) is a disabling secondary headache disorder, with challenging consequences for affected patients and health care resources. It is defined as headache that occurs on ≥ 15 days per month in a patient known to have primary headache disorder due to regular overuse of acute or abortive headache medication for more than 3 months. MOH affects 1-2% of the world's population in their productive age. New advances in headache neurosciences and development of new treatment options specific for headache, along with an understanding of the clinical profile and pathophysiological mechanisms of MOH, can help improve patient outcomes and decrease the burden on the health care system. This work will review MOH, identify updated clinical assessments and recent management approaches.

Preventive treatment can reverse cognitive impairment in chronic migraine

Objective

To study the impact of chronic migraine (CM) on the cognition and quality of life (QoL) of patients in the interictal period, and to analyse the degree of reversibility of any observed alterations following the use of preventive treatment.

Background

CM is a highly disabling disease, and migraineurs often have associated comorbidities, such as subjective memory problems, that are involved in the development of cognitive impairment. Our hypotheses are that patients suffering from chronic migraine experience objective cognitive alterations that are not only due to the pain that they suffer or their current emotional state. Furthermore, preventive treatment should be capable of reversing, or at least reducing, the impact of CM on the cognition and QoL of migraineurs.

Methods

The cognition and QoL of 50 control subjects and 46 patients with CM were assessed using a battery of tests, prior to the use of preventive treatment based on botulinum toxin or oral drugs and after 3 months of this treatment.

Results

Compared with controls, patients with CM had lower scores on the assessment of cognitive performance (Rey-Osterrieth Complex Figure test [ROCF] (p<0.05), Trail Making Test [TMT] B) (p < 0.05) and QoL (p < 0.05). Three months after the use of preventive treatment, improvement was observed in all cognitive parameters (p < 0.05) and QoL (p < 0.05), except the ROCF copy task (p = 0.79). No statistically significant differences were observed when these outcomes were compared based on treatment.

Conclusions

This study confirms poor cognitive performance that is not explained by migraine pain itself, as it occurs in the interictal period, irrespective of the patient’s emotional status. Our findings show that these effects are reversible in some cases with preventive treatment of CM, reaffirming the important impact of this condition on the QoL of these patients, and the need to establish preventive treatment guidelines.

Meta-analytical evidence of functional and structural abnormalities associated with pain processing in migraine patients: An activation likelihood estimation

BACKGROUND

Migraine is a primary headache disorder that causes debilitating throbbing pain. Several functional MRI (fMRI) and voxel-based morphometry (VBM) studies have been used to investigate the structural and functional alteration in migraine. Here, we aim to study the converged brain regions of functional and structural abnormalities in gray matter volume (GMV) associated with pain processing and management in migraineurs and healthy controls (HC).

METHODS

A systematic search through PubMed and Sleuth was carried out for peer-reviewed functional and structural neuroimaging studies on migraine patients and HC yielded a total of 1136 studies. We performed an activation likelihood estimation (ALE) meta-analysis on VBM and pain stimulation task-based fMRI studies to investigate the converged areas of GMV and functional abnormalities between migraineurs and HC. We performed two subgroup analyses between migraine with aura (MwA) and migraine without aura (MwoA) relative to HC, and between chronic migraine (CM) and episodic migraine (EM) compared to HC.

RESULTS

The total sample included 16 fMRI and 22 VBM studies, consisting of 1295 migraine patients, compared to 995 HC. In fMRI analysis, ALE maps for pain stimulation tasks revealed hyperactivation in migraineurs in the substantia nigra compared to HC, whereas hypoactivation was seen in the cerebellum. For the VBM analysis, ALE clusters of increased GMV in migraineurs were observed in the parahippocampus and putamen nucleus. Whereas clusters of reduced GMV in migraineurs were seen in the frontal gyri. Compared to HC, MwoA patients showed a GMV reduction in the insula, and anterior cingulate, whereas MwA patients showed GMV reduction in the cerebellum, cingulate gyrus, and insula. CM patients showed decreased GMV in the precentral gyrus, whereas EM patients showed decreased GMV in the parahippocampus, and inferior frontal gyrus when compared to HC.

CONCLUSIONS

Our findings represent a potential biomarker for the diagnosis and management of migraine, by showing clustered brain regions of abnormal patterns of activation and GMV changes between migraineurs and HC which might be associated with hyposensitivity to pain in migraineurs. Further studies are required to determine disease progression or therapeutic interventions' effect on migraine.

Management of chronic migraine

Chronic migraine is a neurologic disorder associated with considerable disability, lost productivity, and a profound economic burden worldwide. The past five years have seen a dramatic expansion in new treatments for this often challenging condition, among them calcitonin gene related peptide antagonists and neuromodulatory devices. This review outlines the epidemiology of and diagnostic criteria and risk factors for chronic migraine. It discusses evidence based drug and non-drug treatments, their advantages and disadvantages, and the principles of patient centered care for adults with chronic migraine, with attention to differential diagnosis and comorbidities, clinical reasoning, initiation and monitoring, cost, and availability. It discusses the international guidelines on drug treatment for chronic migraine and evaluates non-drug treatments including behavioral and complementary therapies and lifestyle modifications. Finally, it discusses the management of chronic migraine in special populations, including pediatrics, pregnancy, and older people, and considers future questions and emerging research in the field.

Acceptance and commitment therapy for episodic migraine: Rationale and design of a pilot randomized controlled trial

Migraine is a debilitating disorder with limited pharmacological options. Many migraine medications can have intolerable side effects leading patients to seek complementary and integrative health (CIM) approaches for treatment. One option that is growing in popularity and evidence is Acceptance and Commitment Therapy (ACT), a mindfulness-based therapy. The purpose of this paper is to describe how ACT may be an effective modality integrated into the treatment of migraine and to describe the design of a pilot study of ACT for migraine. First, we review the research and the promise of mindfulness therapies for the treatment of migraine. Then, we describe how ACT differs from other mindfulness therapies for migraine and why it can be a promising option for these patients. Finally, we summarize the design of a pilot study designed to determine the feasibility of performing a future fully powered study to determine the effectiveness of ACT on migraine frequency and disability. This pilot study includes unique features, including a remotely-delivered ACT intervention and the measurement of cortisol levels before and after the intervention.

Migraine: interactions between brain's trait and state

It is well established that migraine is a multifactorial disorder. A deep understanding of migraine should be based upon both the underlying traits and the current states affected by different physiological, psychological, and environmental factors. At this point, there is no framework fully meeting these criteria. Here, we describe a broader view of the migraine disorder defined as a dysfunctional brain state and trait interaction. In this model, we consider events that may enhance or diminish migraine responsivity based on an individual's trait and state. This could provide an expanded view for considering how migraine attacks are sometimes precipitated by "triggers" and sometimes not, how these factors only lead to migraine attacks in migraine patients, or how individuals with an increased risk for migraine do not show any symptoms at all. Summarizing recent studies and evidence that support the concept of migraine as a brain state-trait interaction can also contribute to improving patient care by highlighting the importance of precision medicine and applying measures that are able to capture how different traits and states work together to determine migraine.

Avoid or seek light - a randomized crossover fMRI study investigating opposing treatment strategies for photophobia in migraine

Background

Photophobia, the aberrantly increased sensitivity to light, is a common symptom in migraine patients and light discomfort is frequently found as a trigger for migraine attacks. In behavioral studies, planned exposure to light was found to reduce headache in migraine patients with photophobia, potentially by increasing habituation to this migraine trigger. Here, we aimed to elucidate neurophysiological mechanisms of light exposure versus light deprivation in migraine patients using functional magnetic resonance imaging (fMRI).

Methods

Ten migraine patients (9 female, age = 28.70 ± 8.18 years) and 11 healthy controls (9 female, age = 23.73 ± 2.24 years) spent one hour on 7 consecutive days exposed to flashing light (Flash) or darkness (Dark) using a crossover design with a wash-out period of 3 months. Study participants kept a diary including items on interictal and ictal photophobia, presence and severity of headache 7 days before, during and 7 days after the interventions. One week before and one day after both interventions, fMRI using flickering light in a block design was applied. Functional activation was analyzed at whole-brain level and habituation of the visual cortex (V1) was modeled with the initial amplitude estimate and the corrected habituation slope.

Results

Mean interictal photophobia decreased after both interventions, but differences relative to the baseline did not survive correction for multiple comparisons. At baseline, flickering light induced activation in V1 was higher in the patients compared to the controls, but activation normalized after the Flash and the Dark interventions. V1 habituation indices correlated with headache frequency, headache severity and ictal photophobia. In the Flash condition, the individual change of headache frequency relative to the baseline corresponded almost perfectly to the change of the habituation slope compared to the baseline.

Conclusions

On average, light exposure did not lead to symptom relief, potentially due to the short duration of the intervention and the high variability of the patients’ responses to the intervention. However, the strong relationship between visual cortex habituation and headache symptoms and its modulation by light exposure might shed light on the neurophysiological basis of exposure treatment effects.

Trial registration

NCT05369910 (05/06/2022, retrospectively registered).

Dopamine receptor D2 regulates GLUA1-containing AMPA receptor trafficking and central sensitization through the PI3K signaling pathway in a male rat model of chronic migraine

Background

The pathogenesis of chronic migraine remains unresolved. Recent studies have affirmed the contribution of GLUA1-containing AMPA receptors to chronic migraine. The dopamine D2 receptor, a member of G protein-coupled receptor superfamily, has been proven to have an analgesic effect on pathological headaches. The present work investigated the exact role of the dopamine D2 receptor in chronic migraine and its effect on GLUA1-containing AMPA receptor trafficking.

Methods

A chronic migraine model was established by repeated inflammatory soup stimulation. Mechanical, periorbital, and thermal pain thresholds were assessed by the application of von Frey filaments and radiant heat. The mRNA and protein expression levels of the dopamine D2 receptor were analyzed by qRT‒PCR and western blotting. Colocalization of the dopamine D2 receptor and the GLUA1-containing AMPAR was observed by immunofluorescence. A dopamine D2 receptor agonist (quinpirole) and antagonist (sulpiride), a PI3K inhibitor (LY294002), a PI3K pathway agonist (740YP), and a GLUA1-containing AMPAR antagonist (NASPM) were administered to confirm the effects of the dopamine D2 receptor, the PI3K pathway and GULA1 on central sensitization and the GLUA1-containing AMPAR trafficking. Transmission electron microscopy and Golgi-Cox staining were applied to assess the impact of the dopamine D2 receptor and PI3K pathway on synaptic morphology. Fluo-4-AM was used to clarify the role of the dopamine D2 receptor and PI3K signaling on neuronal calcium influx. The Src family kinase (SFK) inhibitor PP2 was used to explore the effect of Src kinase on GLUA1-containing AMPAR trafficking and the PI3K signaling pathway.

Results

Inflammatory soup stimulation significantly reduced pain thresholds in rats, accompanied by an increase in PI3K-P110β subunit expression, loss of dopamine receptor D2 expression, and enhanced GLUA1-containing AMPA receptor trafficking in the trigeminal nucleus caudalis (TNC). The dopamine D2 receptor colocalized with the GLUA1-containing AMPA receptor in the TNC; quinpirole, LY294002, and NASPM alleviated pain hypersensitivity and reduced GLUA1-containing AMPA receptor trafficking in chronic migraine rats. Sulpiride aggravated pain hypersensitivity and enhanced GLUA1 trafficking in CM rats. Importantly, the anti-injury and central sensitization-mitigating effects of quinpirole were reversed by 740YP. Both quinpirole and LY294002 inhibited calcium influx to neurons and modulated the synaptic morphology in the TNC. Additional results suggested that DRD2 may regulate PI3K signaling through Src family kinases.

Conclusion

Modulation of GLUA1-containing AMPA receptor trafficking and central sensitization by the dopamine D2 receptor via the PI3K signaling pathway may contribute to the pathogenesis of chronic migraine in rats, and the dopamine D2 receptor could be a valuable candidate for chronic migraine treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01469-x.

Neurobiology of migraine progression

Chronic migraine is one of the most devastating headache disorders. The estimated prevalence is 1.4-2.2% in the population. The factors which may predispose to the process of migraine progression include high frequency of migraine attacks, medication overuse, comorbid pain syndromes, and obesity. Several studies showed that chronic migraine results in the substantial anatomical and physiological changes in the brain. Despite no clear explanation regarding the pathophysiologic process leading to the progression, certain features such as increased sensory sensitivity, cutaneous allodynia, impaired habituation, identify the neuronal hyperexcitability as the plausible mechanism. In this review, we describe two main mechanisms which can lead to this hyperexcitability. The first is persistent sensitization caused by repetitive and prolonged trigeminal nociceptive activation. This process results in changes in several brain networks related to both pain and non-pain behaviours. The second mechanism is the decrease in endogenous brainstem inhibitory control, hence increasing the excitability of neurons in the trigeminal noceptive system and cerebral cortex. The combination of increased pain matrix connectivity, including hypothalamic hyperactivity and a weak serotonergic system, may contribute to migraine chronification.

Pooled Analysis of Real-World Evidence Supports Anti-CGRP mAbs and OnabotulinumtoxinA Combined Trial in Chronic Migraine

OnabotulinumtoxinA, targeting the CGRP machinery, has been approved for the last two decades for chronic migraine prevention. The recently approved monoclonal antibodies (mAbs) directed towards the calcitonin gene-related peptide (CGRP) pathway open a new age for chronic migraine control. However, some 40% patients suffering from chronic migraine is still resistant to treatment. The aim of this work is to answer the following PICOS (participants intervention comparator outcome study design) question: Is there evidence of efficacy and safety of the combined administration of anti-CGRP mAbs and onabotulinumtoxinA in chronic migraine? A systematic review and meta-analysis [Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations] was made up to 19 April 2022. The results are encouraging: the combined treatment proved to afford ≥50% monthly headache days (MHDs)/frequency reduction respect to baseline in up to 58.8% of patients; in comparison, anti-CGRP mAbs reduce MHDs of 1.94 days from baseline and botulinum toxin of 1.86 days. Our study demonstrates for the first time that the combination therapy of onabotulinumtoxinA with anti-CGRP mAbs affords a reduction of 2.67 MHDs with respect to onabotulinumtoxinA alone, with moderate certainty of evidence. Adequately powered, good-quality studies are needed to confirm the response to combination therapy in terms of efficacy and safety. PROSPERO registration: CRD42022313640.

Rapid response to galcanezumab and predictive factors in chronic migraine patients: A 3-month observational, longitudinal, cohort, multicenter, Italian real-life study

BACKGROUND AND PURPOSE

A rapid response to preventive therapy is of pivotal importance in severely disabled patients with chronic migraine (CM) and diverse preventive treatment failures. This prospective, observational, multicenter real-life study aimed at investigating the effectiveness of galcanezumab in the first 3 months of treatment of CM patients at 14 Italian headache centers.

METHODS

All consecutive adult patients with CM diagnosis with the clinical indication for galcanezumab were considered. We collected patients' baseline characteristics, monthly headache days, monthly painkiller intake, migraine clinical characteristics, and disability scale scores during a 1-month run-in period (baseline) and the first 3 months of therapy. Possible predictive factors of treatment were considered.

RESULTS

A total of 156 patients (82.4% female, aged 47.3 ± 12.3 years) were enrolled. The 65 (41.7%) patients with a consecutive ≥50% response rate (RR) in the 3 months of therapy presented a lower body mass index (p = 0.004) and more frequently presented unilateral migraine pain (p = 0.002) and good response to triptans (p = 0.003). Persistent conversion from CM to episodic migraine was observed in 55.8% (87/156) of patients. They more frequently presented a good response to triptans (p = 0.003) and unilateral pain (p = 0.046). At baseline, 131 of 156 (83.9%) patients presented medication overuse (MO). Of these, 61.8% (81/131) no longer displayed MO consistently during the 3 months. These patients were more frequently responders to triptans (p = 0.002) and less frequently suffered from gastrointestinal comorbidity (p = 0.007).

CONCLUSIONS

Unilateral pain, good response to triptans, and normal weight may be associated with a persistent positive response in the first 3 months of therapy with galcanezumab in CM patients.

Identification of Constituents and Exploring the Mechanism for Toutongning Capsule in the Treatment of Migraine

Toutongning capsule (TTNC) is an effective and safe traditional Chinese medicine used in the treatment of migraine. In this present study, a multiscale strategy was used to systematically investigate the mechanism of TTNC in treating migraine, which contained UPLC-UESI-Q Exactive Focus network pharmacology and experimental verification. First, 88 compounds were identified by the UPLC-UESI-Q Exactive Focus method for TTNC. Then, the target fishing for these compounds was performed by means of an efficient drug similarity search tool. Third, a series of network pharmacology experiments were performed to predict the key compounds, targets, and pathways. They were protein-protein interaction (PPI), KEGG pathway enrichment analysis, and herbs-compounds-targets-pathways (H-C-T-P) network construction. As a result, 18 potential key compounds, 20 potential key targets, and 6 potential signaling pathways were obtained for TTNC in treatment with migraine. Finally, molecular docking and experimental were carried out to verify the key targets. In short, the results showed that TTNC is able to treat migraine through multiple components, multiple targets, and multiple pathways. This work may provide a theoretical basis for further research on the molecular mechanism of TTNC in the treatment of migraine.

Prevalent migraine as a predictor of incident hypertension

Background

Migraine has been associated with several diseases. This population-based prospective Finnish postal survey Health and Social Support Study explored whether self-reported migraine predicted incident hypertension independently in a working-age population by utilizing two data sources: the baseline survey from the year 1998 in combination with the follow-up survey data from the years 2003 and 2012 with linkage to the national Social Insurance Institution registry data of the special reimbursement medication for hypertension from 1999 to 2013. The survey follow-up reached until the second follow-up in the year 2012. The register follow-up also included the year 2013.

Methods

The present population-based prospective cohort study, utilizing two different data sources, included 8593 respondents (22.7% response rate) who participated in 1998, 2003, and 2012 but who did not report hypertension at the baseline in 1998, and whose responses could be linked with the Social Insurance Institution registry data from the beginning of 1999 to the end of 2013. The multivariable logistic regression analysis was based on the combined two data sets.

Results

A significant association of self-reported migraine and incident hypertension (odds ratio 1.37; 95% confidence interval 1.20–1.57) prevailed in the multiple logistic regression analysis adjusted for central socio-demographic and health behaviour variables.

Conclusion

Extra attention should be paid to prevention and control of hypertension in working-age migraine patients.

Reductions in acute medication use and healthcare resource utilization in patients with chronic migraine: a secondary analysis of a phase 3, randomized, double-blind, placebo-controlled study of galcanezumab with open-label extension (REGAIN)

AIMS

To analyze secondary objectives of the REGAIN study related to acute headache medication use and healthcare resource utilization (HCRU) in patients with chronic migraine treated with galcanezumab, a monoclonal antibody to calcitonin gene-related peptide.

METHODS

Adults with chronic migraine (N = 1,113) were randomized (2:1:1) and treated with double-blind monthly injections of placebo, galcanezumab-120 mg, or galcanenzumab-240 mg for 3 months, followed by a 9-month open-label extension with 120 or 240 mg/month galcanezumab. Headache and medication information was collected by daily eDiary. HCRU was reported for the 6 months before randomization, monthly thereafter, and converted to rate per 100-patient-years.

RESULTS

At baseline, 63-64% of patients met criteria for acute headache medication overuse. At Month 3, incidence of headache medication overuse in the galcanezumab groups (33% and 33%) was significantly lower than in the placebo group (46%, both p < .001) and was 16% and 23% in the previous-galcanezumab groups at Month 12. From a baseline of 14.5 to 15.5, reduction in mean number of monthly migraine headache days with acute headache medication use was also significantly greater in the galcanezumab groups at Month 3 (-4.2 and -4.9) than in placebo (-2.6, both p < .001), with reductions of -6.8 and -7.6 in the previous-galcanezumab groups at Month 12. Migraine-specific HCRU rates decreased for all groups, with no significant between-group differences at Month 3. At Month 12, in the two previous-galcanezumab groups, emergency room visits decreased by 58% and 75%, hospital admissions by 100%, and healthcare professional visits by 54% and 67%.

LIMITATIONS

Only 3 months of double-blind, placebo-controlled data, a longer HCRU recall period for baseline than postbaseline, and patients receiving care in the clinical trial itself, may limit generalizability.

CONCLUSIONS

Treatment with galcanezumab resulted in significant reductions in headache medication overuse and migraine headache days requiring acute medication use, with notable reductions in migraine-specific HCRU.

A Qualitative Study to Explore Patient Perspectives of Prophylactic Treatment with OnabotulinumtoxinA for Chronic Migraine

INTRODUCTION

OnabotulinumtoxinA (OBT-A) is one of the most studied prophylactic treatments for chronic migraine. Large clinical trials, and now real-world studies, continue to provide evidence to support the use of OBT-A as an effective treatment to manage chronic migraine. The objective of this study was to explore patient experience and perception of prophylactic treatment with OBT-A for chronic migraine.

METHODS

Data were collected using semi-structured interviews using open-ended questions to uncover rich descriptive data on patient experiences. Interviews were transcribed and analysed using NVivo data analysis software to code and identify themes across the dataset. Three patient groups were included in the analysis: (1) patients who were receiving continued OBT-A treatment; (2) patients who discontinued OBT-A treatment; (3) patients who were recommended for OBT-A treatment but did not proceed.

RESULTS

For patients who received at least one OBT-A treatment, four main themes emerged, which described patients' expectations, experiences, and feelings towards their treatment decisions. Two main themes emerged that were common to patients, who had discontinued their treatment and those, who were recommended for OBT-A treatment but did not proceed, which were identified as potential barriers to initiate or continue prophylactic treatment with OBT-A.

CONCLUSION

Understanding patients' perspective is an important part of clinical practice and may impact on decision-making. Qualitative data can provide a more holistic view of patient care and treatment insights that may not be evaluated during a clinical trial. This study revealed potential barriers to treatment that can inform future policy and practice.

Adult Abdominal Migraine Improved by OnabotulinumtoxinA Injections

Abdominal migraine is often regarded as a childhood disorder and less commonly described in adults. However, gastrointestinal symptoms are known to occur to adult migraine patients, and recognition of adult abdominal migraine may facilitate treatment of the recurrent abdominal symptoms and avoidance of unproductive and sometimes invasive therapies. Here, I describe a patient with chronic migraine headaches and recurrent abdominal pain both of which showed sustained improvement after treatment with onabotulinumtoxinA injections.

Detecting Abnormal Neuronal Activity in a Chronic Migraine Model by Egr1-EGFP Transgenic Mice

Chronic migraine (CM) is a highly disabling neurological disorder characterized by recurrent headache accompanied by a variety of sensory and/or emotional symptoms. However, the mechanisms of migraine onset and its chronicity have not been elucidated. The present study was designed to search for brain regions and neurons that were abnormally activated by CM and might be related to its pathogenesis and different concomitant symptoms. CM models were established here by repeated intraperitoneal injection of nitroglycerin (NTG) every other day for 9 days to early growth response gene 1 (Egr1)-enhanced green fluorescent protein (EGFP) transgenic mice, which allowed monitoring of neuronal activities in the whole brain. CM-related behaviors were recorded through head grooming test and light aversion assay. Elevation of Egr1 expression signals was detected in trigeminal nucleus caudalis (TNC), primary somatosensory cortex (SSp), lateral amygdala nucleus (LA), primary visual area (VISp), and temporal association areas (TEa) 2 h after the last injection of NTG by immunofluorescence and digital slice scanning technology. Meanwhile, no change of Egr1 expression was found in auditory areas (AUD), CA1, ectorhinal area (ECT), piriform (PIR), and anterior cingulate area (ACC). Furthermore, with the strongest support by evidence-based medicine among the current limited oral treatments of CM, topiramate was administrated every day for 11 days from 2 days before the first NTG injection. The results showed that topiramate partially improved the photophobia behavior of CM models in the short-term with gradually weakened efficacy as the course of the disease prolonged. Meanwhile, NTG-induced increase in Egr1 expression was completely reversed in TNC, SSp, and VISp and partially reduced in LA and TEa by topiramate at the same time point mentioned above. In conclusion, the current results suggested that the abnormal hyperactivities in TNC, SSp and VISp were associated with the pathogenesis of CM.

Chronic Migraine Pathophysiology and Treatment: A Review of Current Perspectives

Chronic migraine is a disabling neurological disorder that imposes a considerable burden on individual and socioeconomic outcomes. Chronic migraine is defined as headaches occurring on at least 15 days per month with at least eight of these fulfilling the criteria for migraine. Chronic migraine typically evolves from episodic migraine as a result of increasing attack frequency and/or several other risk factors that have been implicated with migraine chronification. Despite this evolution, chronic migraine likely develops into its own distinct clinical entity, with unique features and pathophysiology separating it from episodic migraine. Furthermore, chronic migraine is characterized with higher disability and incidence of comorbidities in comparison to episodic migraine. While existing migraine studies primarily focus on episodic migraine, less is known about chronic migraine pathophysiology. Mounting evidence on aberrant alterations suggest that pronounced functional and structural brain changes, central sensitization and neuroinflammation may underlie chronic migraine mechanisms. Current treatment options for chronic migraine include risk factor modification, acute and prophylactic therapies, evidence-based treatments such as onabotulinumtoxinA, topiramate and newly approved calcitonin gene-related peptide or receptor targeted monoclonal antibodies. Unfortunately, treatments are still predominantly ineffective in aborting migraine attacks and decreasing intensity and frequency, and poor adherence and compliance with preventative medications remains a significant challenge. Novel emerging chronic migraine treatments such as neuromodulation offer promising therapeutic approaches that warrant further investigation. The aim of this narrative review is to provide an update of current knowledge and perspectives regarding chronic migraine background, pathophysiology, current and emerging treatment options with the intention of facilitating future research into this debilitating and largely indeterminant disorder.

Activation of microglial GLP-1R in the trigeminal nucleus caudalis suppresses central sensitization of chronic migraine after recurrent nitroglycerin stimulation

Background

Central sensitization is considered a critical pathogenic mechanism of chronic migraine (CM). Activation of microglia in the trigeminal nucleus caudalis (TNC) contributes to this progression. Microglial glucagon-like peptide-1 receptor (GLP-1R) activation can alleviate pain; however, whether it is involved in the mechanism of CM has not been determined. Thus, this study aims to investigate the precise role of GLP-1R in the central sensitization of CM.

Methods

Repeated nitroglycerin injection-treated mice were used as a CM animal model in the experiment. To identify the distribution and cell localization of GLP-1R in the TNC, we performed immunofluorescence staining. Changes in the expression of GLP-1R, Iba-1, PI3K and p-Akt in the TNC were examined by western blotting. To confirm the effect of GLP-1R and PI3K/Akt in CM, a GLP-1R selective agonist (liraglutide) and antagonist (exendin(9–39)) and a PI3K selective antagonist (LY294002) were administered. Mechanical hypersensitivity was measured through von Frey filaments. To investigate the role of GLP-1R in central sensitization, calcitonin gene-related peptide (CGRP) and c-fos were determined using western blotting and immunofluorescence. To determine the changes in microglial activation, IL-1β and TNF-α were examined by western blotting, and the number and morphology of microglia were measured by immunofluorescence. We also confirmed the effect of GLP-1R on microglial activation in lipopolysaccharide-treated BV-2 microglia.

Results

The protein expression of GLP-1R was increased in the TNC after nitroglycerin injection. GLP-1R was colocalized with microglia and astrocytes in the TNC and was fully expressed in BV-2 microglia. The GLP-1R agonist liraglutide alleviated basal allodynia and suppressed the upregulation of CGRP, c-fos and PI3K/p-Akt in the TNC. Similarly, the PI3K inhibitor LY294002 prevented nitroglycerin-induced hyperalgesia. In addition, activating GLP-1R reduced Iba-1, IL-1β and TNF-α release and inhibited TNC microglial number and morphological changes (process retraction) following nitroglycerin administration. In vitro, the protein levels of IL-1β and TNF-α in lipopolysaccharide-stimulated BV-2 microglia were also decreased by liraglutide.

Conclusions

These findings suggest that microglial GLP-1R activation in the TNC may suppress the central sensitization of CM by regulating TNC microglial activation via the PI3K/Akt pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01302-x.

Comparison of cervical muscle isometric force between migraine subgroups or migraine-associated neck pain: a controlled study

This study aimed to verify if migraine frequency or migraine-associated neck pain were associated with a reduction of normalized force and altered electromyographic activity during maximal cervical muscle isometric contractions. Additionally, it aimed to assess the correlation of normalized isometric force with years with migraine, headache frequency, headache intensity, migraine-related disability, and severity of cutaneous allodynia. The sample comprises 71 women with migraine (40/31 episodic/chronic, 42/18 with/without neck pain) and 32 women without headache. Cervical muscle isometric force in flexion, extension, and lateral flexion was assessed synchronized with the acquisition of superficial electromyography from the cervical muscles. Women with episodic migraine presented lower normalized isometric force in extension, flexion, and right and left lateral flexions than controls (P < 0.05). Women with migraine and neck pain exhibited lower cervical extension and right/left lateral-flexions normalized isometric force than controls (P < 0.05). No significant differences were observed in antagonist activity. Normalized isometric force in all directions showed weak to moderate correlations with the severity of self-reported symptoms of cutaneous allodynia (- 0.25 ≥ r ≥ - 0.39). No additional linear correlation with clinical migraine features was observed. In conclusion, cervical muscle weakness may be associated with episodic migraine and neck pain concurrent with migraine attacks without altered antagonist activity. Additionally, it may also be related to the severity of cutaneous allodynia.

Orexin one receptors within the basolateral amygdala are involved in the modulation of cognitive deficits associated with a migraine-like state in rats

OBJECTIVES

This study explored the possible role of orexin one receptors (Orx1R) in the basolateral amygdala (BLA) on the modulation of nitroglycerin (NTG)-induced migraine-like symptoms. In addition, pain-induced subsequent alteration in learning and memory competence was evaluated in the adult male Wistar rats.

METHODS

The rats were given NTG (5 mg/kg, i.p.) every two days (for nine-day) to induce a migraine-like state. The migraine animals were treated with intra-BLA infusion of an Orx1R antagonist SB 334,867 (10, 20, and 40 nM/rat) or its vehicle DMSO. The NTG-induced migraine symptoms were recorded for 90 min. Spatial and passive avoidance performances were assessed by Morris water maze (MWM) and shuttle box tasks, respectively.

RESULTS

In comparison with control, NTG produced significant migraine-like symptoms characterized by a decrease in cage climbing and an increase in head-scratching, freezing, and facial grooming behavior. Intra-BLA infusion of SB 334,867 (40 nM/rat) significantly decreased cage climbing and increased facial grooming responses in NTG-treated rats. Moreover, all administrated doses of SB 334,867 increased NTG-evoked head-scratching and freezing behavior. Besides, NTG impaired learning and memory performances in both tests, which were exaggerated by post-injection of SB 334,867 (40 nM/rat).

CONCLUSIONS

Overall, the data provided an emerging role for the orexin system within BLA in the modulation of cognitive decline comorbid with migraine in rats.

Daily Headache in Chronic Migraine Is a Predictive Factor of Response in Patients Who Had Completed Three Sessions of OnabotulinumtoxinA

OnabotulinumtoxinA is one of the main preventive treatments for chronic migraine. Despite that up to one third of patients with chronic migraine suffer from daily headache, these individuals have hardly been studied. We conducted a prospective cohort study, including patients with chronic migraine and treated with OnabotulinumtoxinA according to the PREEMPT paradigm. The primary endpoint was to assess whether patients with chronic migraine and daily headache had a different response after three sessions of OnabotulinutoxinA than patients without daily headache. The secondary endpoint was to analyse the presence of predictive factors that could be associated with a higher response to OnabotulinumtoxinA. Patients with daily headache had a reduction of 14.9 (SD: 9.7) headache days per month, patients with 22–29 headache days a reduction of 10.6 (SD: 9.9) days, and patients with 15–21 headache days a reduction of 8.6 (SD: 7.1) days (p < 0.001). In the univariate regression analysis, a higher number of headache days per month at baseline was associated with higher odds of reduction in the number of headache days per month after OnabotulinumtoxinaA treatment (OR: 0.474, 95% CI: 0.278–0.670, p < 0.001). This association was maintained in the multivariate regression analysis (OR: 0.540, 95% CI: 0.333–0.746, p < 0.001). In our sample, daily headache was not associated with a worse response to OnabotulinumtoxinA treatment. A higher frequency of headache at baseline was a predictor of better response to OnabotulinumtoxinA treatment.

Safety and tolerability of preventive treatment options for chronic migraine

INTRODUCTION

Relative to migraine generally, chronic migraine (CM) imposes greater disability, healthcare utilization and socioeconomic burden. Six therapies currently possess a credible evidence base for prevention/suppression of CM. This review is intended to provide an assessment of their relative utility, defined as a blend of safety, tolerability and efficacy, focusing in particular on their safety and tolerability.Areas Covered: We discuss all six medications currently FDA-approved for migraine prevention which also specifically possess credible evidence of efficacy in treating CM. While we do address the efficacy of each, our primary emphasis involves assessment of safety and tolerability data derived from clinical trials and post-marketing experience.Expert Opinion: Recent research involving CM has led to the identification of highly targeted and typically well-tolerated therapies. For patients who experience obstacles to accessing these newer therapies, topiramate is available as an evidence-based alternative, but contraindications, drug-drug interactions and poor tolerability may limit or prevent its use. Although data to support such intervention presently is limited, clinically challenging CM cases may benefit from combination therapy. 'Real world' studies are needed to evaluate such polytherapy, along with studies intended to assess the long-term safety of the individual therapies and their use during pregnancy and breast-feeding.

Calcitonin Gene-Related Peptide Monoclonal Antibody Versus Botulinum Toxin for the Preventive Treatment of Chronic Migraine: Evidence From Indirect Treatment Comparison

Background: The previously approved botulinum toxin and nowadays promising calcitonin gene-related peptide (CGRP) monoclonal antibody have shown efficacy for preventing chronic migraine (CM). However, there is no direct evidence for their relative effectiveness and safety. In this study, we conducted an indirect treatment comparison to compare the efficacy and safety of CGRP monoclonal antibody with botulinum toxin for the preventive treatment of chronic migraine.

Methods: Up to August 31, 2020, we systematically searched PubMed, Embase, and Cochrane Library Central Register of Controlled Trials (Central). Weighted mean difference (WMD) and relative risk (RR) were used to evaluate clinical outcomes. Indirect treatment comparison (ITC) software was used to conduct indirect treatment comparison.

Results: Ten studies were pooled with 6,325 patients in our meta-analysis. Both botulinum toxin and CGRP monoclonal antibody demonstrated favorable efficacy in the change of migraine days, headache days, HIT-6 score, and 50% migraine responder rate compared with placebo. In indirect treatment comparison, CGRP monoclonal antibody was superior to botulinum toxin in the frequency of acute analgesics intake (WMD = −1.31, 95% CI: −3.394 to 0.774, p = 0.02113), the rate of treatment-related adverse events (AEs) (RR = 0.664, 95% CI: 0.469 to 0.939, p = 0.04047), and the rate of treatment-related serious adverse events (RR = 0.505, 95% CI: 0.005 to 46.98, p < 0.001).

Conclusion: For chronic migraine patients, CGRP monoclonal antibody was slightly better than botulinum toxin in terms of efficacy and safety. In the future, head-to-head trials would be better to evaluate the efficacy and safety between different medications in the prevention of chronic migraine.

Persistent Brainstem Dysfunction in Long-COVID: A Hypothesis

Long-COVID is a postviral illness that can affect survivors of COVID-19, regardless of initial disease severity or age. Symptoms of long-COVID include fatigue, dyspnea, gastrointestinal and cardiac problems, cognitive impairments, myalgia, and others. While the possible causes of long-COVID include long-term tissue damage, viral persistence, and chronic inflammation, the review proposes, perhaps for the first time, that persistent brainstem dysfunction may also be involved. This hypothesis can be split into two parts. The first is the brainstem tropism and damage in COVID-19. As the brainstem has a relatively high expression of ACE2 receptor compared with other brain regions, SARS-CoV-2 may exhibit tropism therein. Evidence also exists that neuropilin-1, a co-receptor of SARS-CoV-2, may be expressed in the brainstem. Indeed, autopsy studies have found SARS-CoV-2 RNA and proteins in the brainstem. The brainstem is also highly prone to damage from pathological immune or vascular activation, which has also been observed in autopsy of COVID-19 cases. The second part concerns functions of the brainstem that overlap with symptoms of long-COVID. The brainstem contains numerous distinct nuclei and subparts that regulate the respiratory, cardiovascular, gastrointestinal, and neurological processes, which can be linked to long-COVID. As neurons do not readily regenerate, brainstem dysfunction may be long-lasting and, thus, is long-COVID. Indeed, brainstem dysfunction has been implicated in other similar disorders, such as chronic pain and migraine and myalgic encephalomyelitis or chronic fatigue syndrome.

Ubrogepant to Treat Acute Migraine in Adults

Migraine is a neurobiological headache disorder that affects around 16% of adults in the United States. Medical treatment of mild to moderate migraines include non-prescription non-steroidal anti-inflammatory drugs, acetaminophen, or aspirin and caffeine-containing combination analgesics. Additionally, moderate to severe migraines and those that are mild to moderate that have not responded to analgesics can be treated with triptans, which are drugs specific for migraine treatment. Non-pharmacological treatments include cognitive behavioral therapy and relaxation training. Medications for the prevention of migraines have also been developed since they are more affective in offsetting the symptoms. Ubrogepant's high specificity and selectivity for calcitonin gene-related peptide (CGRP) sets it apart from certain other drugs, which previously limited the treatment of migraines with or without aura due to their decreased selectivity. The most frequently reported side effects are oropharyngeal pain, nasopharyngitis, and headache. Most studies found that participants receiving Ubrogepant were free from pain within 2 h when compared to placebo. Patients taking Ubrogepant should avoid taking it when pregnant or with end stage renal disease. In summary, Ubrogepant has good tolerability and an overall favorable safety profile. It appears to hold promise for the acute treatment of migraines with or without aura in adults.

Mild systemic inflammation enhances response to OnabotulinumtoxinA in chronic migraineurs

The anti-inflammatory effect of OnabotulinumtoxinA (OnabotA) has been a matter of discussion for many years. In chronic migraine, however, increased pro-inflammatory state is associated with good response to OnabotA. We aimed to investigate whether a mild systemic inflammatory state elicited by a common oral infection (periodontitis) could enhance treatment response to OnabotA. In this study, we included 61 chronic migraineurs otherwise healthy treated with OnabotA of which 7 were poor responders and 54 good responders. Before receiving OnabotA therapy, all participants underwent a full-mouth periodontal examination and blood samples were collected to determine serum levels of calcitonin gene-related peptide (CGRP), interleukin 6 (IL-6), IL-10 and high sensitivity C-reactive protein (hs-CRP). Periodontitis was present in 70.4% of responders and 28.6% of non-responders (P = 0.042). Responders showed greater levels of inflammation than non-responders (IL-6: 15.3 ± 8.7 vs. 9.2 ± 4.7 ng/mL, P = 0.016; CGRP: 18.8 ± 7.6 vs. 13.0 ± 3.1 pg/mL, P = 0.002; and hs-CRP: 3.9 ± 6.6 vs. 0.9 ± 0.8 mg/L, P = 0.003). A linear positive correlation was found between the amount of periodontal tissue inflamed in the oral cavity and markers of inflammation (IL-6: r = 0.270, P = 0.035; CGRP: r = 0.325, P = 0.011; and hs-CRP: r = 0.370, P = 0.003). This report shows that in presence of elevated systemic inflammatory markers related to periodontitis, OnabotA seems to reduce migraine attacks. The changes of scheduled inflammatory parameters after treatment and subsequent assessment during an adequate period still need to be done.

Changes in patient functioning and disability: results from a phase 3, double-blind, randomized, placebo-controlled clinical trial evaluating galcanezumab for chronic migraine prevention (REGAIN)

PURPOSE

To evaluate secondary outcomes including changes in functioning and disability associated with galcanezumab, a humanized monoclonal antibody to calcitonin gene-related peptide, in patients with chronic migraine.

METHODS

Patients randomly received galcanezumab (120 mg n = 278, 240 mg n = 277) or placebo (n = 558) during 3 months of double-blind treatment, followed by a 9-month open-label extension. The Migraine-Specific Quality-of-Life Questionnaire v2.1 (MSQv2.1) measured the impact of migraine on patient functioning. The Migraine Disability Assessment (MIDAS) quantified headache-related disability. Changes from baseline were analyzed with mixed model repeated measures or analysis of covariance.

RESULTS

Total MSQ score at baseline was 44.88 ± 18.02 (mean ± SD), indicating significant functional impairment. At Month 3, least squares (LS) mean change ± SE in total MSQ for galcanezumab-treated patients were 20.51 ± 1.49 (120 mg) and 20.49 ± 1.49 (240 mg), both statistically significantly greater vs placebo-treated patients (14.55 ± 1.21; both P < 0.001). Total MIDAS score at baseline was 67.24 ± 57.31 (mean ± SD). At Month 3, LS mean change ± SE from baseline in total MIDAS for galcanezumab-treated patients was statistically significantly greater than placebo for 120 mg group (placebo: - 11.53 ± 3.38 vs 120 mg: - 20.27 ± 4.07; P < 0.05) but not for 240 mg group (- 17.02 ± 4.05). At Month 12, within-group mean changes from baseline for total MSQ (28.56 ± 1.19 previous placebo; 29.53 ± 1.51 previous 120 mg; 25.83 ± 1.49 previous 240 mg) and MIDAS scores (- 28.47 ± 2.95 previous placebo; - 31.47 ± 3.69 previous 120 mg; - 31.13 ± 3.62 previous 240 mg) were statistically significant (P < 0.001) for the open-label treatment population regardless of previous double-blind treatment assignment.

CONCLUSIONS

Galcanezumab-treated patients with chronic migraine reported statistically significant improvements in functioning and disability, representing a clinically significant change.

TRIAL REGISTRATION

ClinicalTrials.gov registry: NCT02614261. Registered 25 November 2015.

Effectiveness of preventive onabotulinumtoxin A injections for migraine headaches is dependent on the circadian time of administration

We have previously shown that quarterly preventive onabotulinumtoxin A (BTA) injections administered to diurnally active patients for chronic migraines (CM) associate with increased discomfort when performed in the morning. The purpose of this study was to further examine if the effectiveness of preventive BTA injections depends on the procedure's circadian timing. A total of 90 diurnally active patients with a medical history of CM and undergoing BTA injection therapy were enrolled in the study. One hundred and fifty-five units of BTA were administered according to the standardized PREEMPT protocol, either during the course of morning (AM) or afternoon (PM) clinic hours. Patients were asked to keep headache diaries, which were reviewed at the time of their follow-up BTA injections 3 months later. The number of headache days experienced during the first, second, and third month following BTA injection, and the number of headache days during the last 7 days prior to follow-up was collected, as was the self-rating of the effectiveness of BTA treatment. Fifty-five (61%) patients were injected during the AM clinic and 35 (39%) during the PM clinic. There was no difference in gender, race, and age variables between the AM and PM patients. The average total number of headache days during 3 months following injection was significantly higher for the AM-treated compared to the PM-treated patients (22.37 ± 18.85 vs. 10.54 ± 7.5, p =.0007). AM patients also reported a higher number of headache days during each of the 3 months following BTA injection. In contrast, PM patients reported higher effectiveness of preventive BTA treatment. The average number of headache days during the week prior to the follow up, as well as the presence of headache on the day of the follow-up was not significantly different between the AM and PM groups. Scheduling diurnally active CM patients with stable circadian sleep/wake routine for afternoon BTA injections appear to improve the effectiveness of BTA therapy as well as patients' satisfaction with the treatment.

Beyond Amitriptyline: A Pediatric and Adolescent Oriented Narrative Review of the Analgesic Properties of Psychotropic Medications for the Treatment of Complex Pain and Headache Disorders

Children and adolescents with recurrent or chronic pain and headache are a complex and heterogenous population. Patients are best served by multi-specialty, multidisciplinary teams to assess and create tailored, individualized pain treatment and rehabilitation plans. Due to the complex nature of pain, generalizing pharmacologic treatment recommendations in children with recurrent or chronic pains is challenging. This is particularly true of complicated patients with co-existing painful and psychiatric conditions. There is an unfortunate dearth of evidence to support many pharmacologic therapies to treat children with chronic pain and headache. This narrative review hopes to supplement the available treatment options for this complex population by reviewing the pediatric and adult literature for analgesic properties of medications that also have psychiatric indication. The medications reviewed belong to medication classes typically described as antidepressants, alpha 2 delta ligands, mood stabilizers, anti-psychotics, anti-sympathetic agents, and stimulants.

Reversion From Chronic Migraine to Episodic Migraine in Patients Treated With Fremanezumab: Post Hoc Analysis From HALO CM Study

Background

Migraine preventive medications are used to reduce headache frequency, severity, and duration. In patients with chronic migraine (CM), reversion to episodic migraine (EM) is an important treatment goal.

Objective

To evaluate the effect of fremanezumab on the rate of reversion from CM to EM.

Methods

This phase 3, randomized, double‐blind, placebo‐controlled, parallel‐group trial included a 28‐day pretreatment period and a 3‐month treatment period. Patients with CM received subcutaneous fremanezumab quarterly (675 mg at baseline) or monthly (675 mg at baseline; 225 mg at Weeks 4 and 8), or placebo. Post hoc analyses evaluated the proportion of patients who reverted from CM to EM, defined as either a reduction to an average of <15 headache days per month during the 3‐month treatment period or a reduction to <15 headache days per month in all 3 months of the treatment period.

Results

This analysis included data from 1088 CM patients (quarterly, n = 366; monthly, n = 365; placebo, n = 357). More fremanezumab‐treated patients with CM reverted to EM using either the monthly average number of headache days criteria for reversion (quarterly: 50.5% [185/366], P = .108; monthly: 53.7% [196/365], P = .012; vs placebo: 44.5% [159/357]) or the monthly headache day count at Months 1, 2, and 3 criteria for reversion (quarterly: 31.2% [114/366], P = .008; monthly: 33.7% [123/365], P = .001; vs placebo: 22.4% [80/357]). Patients with CM who reported previous topiramate or onabotulinumtoxinA use, concomitant preventive medication use, or medication overuse were less likely to revert to EM.

Conclusions

Fremanezumab may offer the benefit of reversion from CM to EM, based on a reduction in the number of headache days over 3 months of treatment.

Role of greater occipital nerve block for preventive treatment of chronic migraine: A critical review

Objective:

The aim of this study is to critically analyze the evidence of the efficacy and safety of greater occipital nerve (GON) block for the preventive treatment of chronic migraine (CM).

Background:

A rigorous scientific assessment of efficacy and safety of the GON block for preventive treatment in CM is not available. This critical review was undertaken for this purpose.

Methods:

References for this review were identified by searches of articles published in the English language in PubMed between 1969 and April 15, 2020 using “greater occipital nerve block,” “chronic migraine,” “migraine,” “headache,” and “treatment” as keywords.

Results:

Out of potential 532 articles, 9 open-label and 4 placebo-controlled trials that studied the role of GON block for prevention of CM were identified and reviewed. Open-label trials reported a reduction of headache severity and frequency in 35–68% of patients. The beneficial effect of a single block lasted up to 4 weeks. Randomized controlled trials (RCTs) used varied methodology and techniques of GON block and the outcomes were reported at different time points. A single RCT showed a beneficial effect of the GON block at 1 week. However, the GON block was found to be safe and well tolerated.

Conclusion:

Long-term efficacy of GON block in CM shall need further well-designed RCTs using standardized methodology. This study, in addition, reviewed the limitations and uncertainties regarding the technique and methods of use of GON block in CM.

Effect of Headache-Free Days on Disability, Productivity, Quality of Life, and Costs Among Individuals with Migraine

BACKGROUND

The functional impairment associated with migraine can cause physical, emotional, and economic ramifications that can affect occupational, academic, social, and family life. Understanding the relationship between headache-free days (HFDs) and the disease burden of migraine may help with decisions regarding treatment and management of migraine.

OBJECTIVE

To determine the relationship between burden of disease measures and HFDs among individuals with migraine experiencing ≥ 4 headache days in the previous 30 days.

METHODS

The 2016 U.S. National Health and Wellness Survey (N = 97,503) was self-administered to a nationally representative sample of adults. Respondents with a migraine diagnosis who reported ≥ 4 headache days a month were included in the analysis. The primary independent variable was the number of HFDs assessed as both a continuous (HFDs in the previous 30 days) and categorical (0-10, 11-20, and 21-26 HFDs) measure. HFDs were used to predict outcomes using separate generalized linear models. Outcomes included effect on functional status and well-being, measured by the 6-item Headache Impact Test (HIT-6) score; number of days of work and/or household activities missed due to migraine; annualized indirect costs due to work productivity loss (assessed via the Work Productivity and Activity Impairment questionnaire); and annualized direct costs due to health care resource use (health care provider visits, emergency room visits, and hospitalizations).

RESULTS

The survey included 372 respondents with diagnosed migraine and ≥ 4 headache days per month. Using HFDs as a continuous variable, each additional HFD was associated with a 0.15-point reduction in HIT-6 scores, a 5% reduction in both number of work days and household activities missed, and a 4% reduction in indirect costs; thus, a 5-day increase in HFDs would lead to a 0.75-point reduction in HIT-6 scores, 25% reduction in days of work or household activities missed, and 20% reduction in indirect costs. Analyzing HFDs as a categorical variable, respondents experiencing 21-26 HFDs had lower HIT-6 total scores than those with 0-10 HFDs (adjusted means: 66.59 vs. 63.91; P = 0.001) or those with 11-20 HFDs (65.66 vs. 63.91, P = 0.015). Respondents experiencing 21-26 HFDs missed fewer work days than those with 0-10 HFDs (4.44 vs. 1.46, P = 0.002) or those with 11-20 HFDs (3.36 vs. 1.46, P = 0.009). Similarly, respondents with 11-20 HFDs (22.99 vs. 9.72, P < 0.001) and those with 21-26 HFDs (22.99 vs. 7.34, P = 0.001) were associated with fewer days of household activities missed due to migraine compared with respondents with 0-10 HFDs. Respondents with 21-26 HFDs per month had significantly lower indirect costs ($16,975 vs. $6,919, P = 0.025) than those with 0-10 HFDs.

CONCLUSIONS

A higher number of HFDs is associated with decreased headache-related disability among those with migraine. Interventions that increase the total number of HFDs may reduce the burden and cost associated with migraine.

DISCLOSURES

This study was funded by Teva Pharmaceutical Industries (Petach Tikva, Israel). Cohen is an employee of Teva Branded Pharmaceutical Products R&D (USA); Bell was employed by Teva Pharmaceutical Industries at the time of this study and has stock/stock options in Teva Pharmaceutical Industries. Lee is employed by Kantar, which received payment from Teva Pharmaceutical Industries for data analyses performed for this study. Lipton has received research support from the NIH, the Migraine Research Foundation, and the National Headache Foundation. He has reviewed for the NIA and NINDS; holds stock options in eNeura Therapeutics and Biohaven Holdings; and serves as consultant, advisory board member, or has received honoraria from the American Academy of Neurology, Alder, Allergan, American Headache Society, Amgen, Autonomic Technologies, Avanir, Biohaven, Biovision, Boston Scientific, Dr. Reddy's, electroCore, Eli Lilly, eNeura Therapeutics, GlaxoSmithKline, Merck, Pernix, Pfizer, Supernus, Teva, Trigemina, Vector, and Vedanta. Saikali serves on the advisory board and as speaker for Allergan, Amgen, Promius, Supernus, and Teva Pharmaceuticals. He serves as a speaker for Assertio, Avanir, Cefaly, Egalet, Eli Lilly, Gammacore, and Pernix. This study has been presented as a poster at the American Academy of Neurology 2018 Annual Meeting, April 21-27, 2018, in Los Angeles, CA; Headache Update 2017, July 13-16, 2017, in Lake Buena Vista, FL; and the American Headache Society 2017 Annual Meeting, June 8-11, 2017, in Boston, MA.

Pharmacological options for the treatment of chronic migraine pain

Migraine is a debilitating neurological condition with symptoms typically consisting of unilateral and pulsating headache, sensitivity to sensory stimuli, nausea, and vomiting. The World Health Organization (WHO) reports that migraine is the third most prevalent medical disorder and second most disabling neurological condition in the world. There are several options for preventive migraine treatments that include, but are not limited to, anticonvulsants, antidepressants, beta blockers, calcium channel blockers, botulinum toxins, NSAIDs, riboflavin, and magnesium. Patients may also benefit from adjunct nonpharmacological options in the comprehensive prevention of migraines, such as cognitive behavior therapy, relaxation therapies, biofeedback, lifestyle guidance, and education. Preventative therapies are an essential component of the overall approach to the pharmacological treatment of migraine. Comparative studies of newer therapies are needed to help patients receive the best treatment option for chronic migraine pain.

Lasmiditan mechanism of action - review of a selective 5-HT1F agonist

Migraine is a leading cause of disability worldwide, but it is still underdiagnosed and undertreated. Research on the pathophysiology of this neurological disease led to the discovery that calcitonin gene-related peptide (CGRP) is a key neuropeptide involved in pain signaling during a migraine attack. CGRP-mediated neuronal sensitization and glutamate-based second- and third-order neuronal signaling may be an important component involved in migraine pain. The activation of several serotonergic receptor subtypes can block the release of CGRP, other neuropeptides, and neurotransmitters, and can relieve the symptoms of migraine. Triptans were the first therapeutics developed for the treatment of migraine, working through serotonin 5-HT1B/1D receptors. The discovery that the serotonin 1F (5-HT1F) receptor was expressed in the human trigeminal ganglion suggested that this receptor subtype may have a role in the treatment of migraine. The 5-HT1F receptor is found on terminals and cell bodies of trigeminal ganglion neurons and can modulate the release of CGRP from these nerves. Unlike 5-HT1B receptors, the activation of 5-HT1F receptors does not cause vasoconstriction.The potency of different serotonergic agonists towards 5-HT1F was correlated in an animal model of migraine (dural plasma protein extravasation model) leading to the development of lasmiditan. Lasmiditan is a newly approved acute treatment for migraine in the United States and is a lipophilic, highly selective 5-HT1F agonist that can cross the blood-brain barrier and act at peripheral nervous system (PNS) and central nervous system (CNS) sites.Lasmiditan activation of CNS-located 5-HT1F receptors (e.g., in the trigeminal nucleus caudalis) could potentially block the release of CGRP and the neurotransmitter glutamate, thus preventing and possibly reversing the development of central sensitization. Activation of 5-HT1F receptors in the thalamus can block secondary central sensitization of this region, which is associated with progression of migraine and extracephalic cutaneous allodynia. The 5-HT1F receptors are also elements of descending pain modulation, presenting another site where lasmiditan may alleviate migraine. There is emerging evidence that mitochondrial dysfunction might be implicated in the pathophysiology of migraine, and that 5-HT1F receptors can promote mitochondrial biogenesis. While the exact mechanism is unknown, evidence suggests that lasmiditan can alleviate migraine through 5-HT1F agonist activity that leads to inhibition of neuropeptide and neurotransmitter release and inhibition of PNS trigeminovascular and CNS pain signaling pathways.

The fifth cranial nerve in headaches

The fifth cranial nerve is the common denominator for many headaches and facial pain pathologies currently known. Projecting from the trigeminal ganglion, in a bipolar manner, it connects to the brainstem and supplies various parts of the head and face with sensory innervation. In this review, we describe the neuroanatomical structures and pathways implicated in the sensation of the trigeminal system. Furthermore, we present the current understanding of several primary headaches, painful neuropathies and their pharmacological treatments. We hope that this overview can elucidate the complex field of headache pathologies, and their link to the trigeminal nerve, to a broader field of young scientists.

Suppression of Menstrual-Related Migraine Attack Severity Using Pyridoxine, Thiamine, and Cyanocobalamin: A Quasi-Experimental Within-Subject Design

Background: B-group vitamins can potentially contribute to migraine prophylaxis through various mechanisms. We conducted a quasi-experimental study to assess the efficacy and tolerability of a combination of vitamins B1, B6, and B12 (Neurobion) for prophylaxis of menstruation-related migraine attacks. Methods: Women diagnosed with menstrual-related migraine, both chronic and episodic headaches, were enrolled. The patients began Neurobion therapy one week before the menstruation cycle, and repeated the injection for three consecutive months; each ampoule contained 100 mg of vitamins B1 and B6 as well as 1000 μg of vitamin B12. Neurobion was used as an add-on therapy for patients receiving the same prophylactic therapy during the last two months before the start of the study. The outcome parameter examined the severity of menstrual-related migraine attacks on a 10-point visual analog scale (VAS). Results: Three hundred eighty-three patients (169 with chronic migraine and 214 with episodic migraine) were included in the final analysis. The patients received treatment with a combination of vitamins B1, B6, and B12 with positive results. The mean intensity of menstrual-related migraine attacks was reduced from 6.7 on the 10-point VAS to 3.2 (P < 0.001) in patients with chronic migraine. The mean severity of menstrual-related migraine attacks was also reduced from 7.2 to 3.7 in patients with episodic migraine (P < 0.001). There was no significant difference in the reduction of headache severity between the two groups of migraineurs (P = 0.985). Conclusions: Neurotropic vitamins, including pyridoxine, thiamine, and cyanocobalamin yielded significant reductions in the severity of menstrual-related migraine attacks. Neurobion as a combination of vitamins B1, B6, and B12 appears to be well-tolerated and beneficial as an adjuvant in treatment and prophylaxis of menstrual-related migraine attacks. Further large-scale trials with long-term follow-up will be required to confirm our results.

From transformation to chronification of migraine: pathophysiological and clinical aspects

Chronic migraine is a neurological disorder characterized by 15 or more headache days per month of which at least 8 days show typical migraine features. The process that describes the development from episodic migraine into chronic migraine is commonly referred to as migraine transformation or chronification. Ample studies have attempted to identify factors associated with migraine transformation from different perspectives. Understanding CM as a pathological brain state with trigeminovascular participation where biological changes occur, we have completed a comprehensive review on the clinical, epidemiological, genetic, molecular, structural, functional, physiological and preclinical evidence available.