CGRP may play a causative role in migraine

Calcitonin Gene-Related Peptide Levels in Children and Adolescents With Primary Headache Disorder

ObjectiveThis study aimed to investigate calcitonin gene-related peptide (CGRP) levels in children and adolescents with primary headache.MethodsAll patients underwent blood sampling regardless of their headache state (ictal or interictal) on the day of examination. The patients were grouped based on their headache diagnosis (migraine, tension-type headache, or mixed).ResultsNinety-two patients aged 5-18 years were included (29 diagnosed with migraine and 31 with tension-type headache). In the comparisons between the patients with migraine and the patients with tension-type headache, interictal CGRP levels in blood from the cubital vein showed no significant difference. Ictal samples were collected in the tension-type headache group only, and no significant difference was observed between the ictal and interictal phases. Variables such as headache diagnosis, sex, age, family history with primary headache, headache frequency, time since last headache, medication usage, and body mass index did not significantly influence CGRP levels.ConclusionNo significant difference in interictal CGRP levels between patients with migraine and patients with tension-type headache were found. In patients with tension-type headache, there were no significant differences between CGRP levels in the ictal and interictal state. We were not able to draw conclusions about differences in ictal levels of CGRP in patients with migraine compared with patients with tension-type headache, or in differences between ictal and interictal levels in patients with migraine. Future studies should aim to replicate these results in a larger study cohort.

Zolmitriptan niosomal transdermal patches: combating migraine via epigenetic and endocannabinoid pathways and reversal of migraine hypercoagulability

Conventional zolmitriptan (ZOL) has limited oral bioavailability, many adverse effects, and poor membrane penetrability that negatively influences its accessibility to its 5-HT1B/1D receptor binding pocket, located transmemberanous. This work aimed at preparing transdermal ZOL-nanoformulation (niosomes) to surpass these limitations and to explore novel antimigraine mechanisms for ZOL via modulation of the epigenetically-altered chronification genes (RAMP-1, NPTX-2) or microRNAs and affecting the endocannabinoid CB-1/MAPK pathway. The prepared ZOL niosomes (Fsp60/6-1:1) exhibited %EE of 57.28%, PS of 472.3 nm, PDI of 0.366, and ZP of -26 mV were cast into patch with content uniformity of 93.12%, maintained endurance after 200-times folding, no interaction between its components (FT-IR), a biphasic release pattern and good stability after storage at 4 °C for 6 months. In-vivo ZOL-patch application in rats with nitroglycerin-induced migraine showed significant management of migraine pain symptoms and photophobia assessed behaviorally, decreased brain levels of the trigeminal neuronal activation marker (c-fos), the migraine pain neurotransmitter (CGRP) and the serum levels of different migraine pain markers (substance P, nitric-oxide, and TNF-α). It also significantly decreased RAMP-1, NPTX-2, miR-382-5p, and CB-1/MAPK gene expression reflecting improved efficacy and brain receptors delivery to a much greater extent than conventional ZOL has done. Additionally, this nanoformulation significantly opposed migraine-induced platelet activation and hypercoagulable status in both central and peripheral circulations as evidenced by the significant decrease in adenosine diphosphate, thrombin, factor X, CD41, and Von-Willebrand factor levels assessed peripherally and centrally. TPFsp60/6-1:1 significantly improved ZOL efficacy and accessibility to brain-receptors to a much greater extent than conventional ZOL-solution.KeywordsEndocannabinoid receptors; Epigenetically-altered genes; Hemostatic pathways; Niosomal patch; Transdermal; Zolmitriptan.

Effect of erenumab versus other migraine preventive medications on cardiovascular and cerebrovascular outcomes: A United States claims database-based observational cohort study

OBJECTIVE

To estimate the real-world risk of cardiovascular events among patients with migraine treated with erenumab and other migraine preventive medications.

BACKGROUND

Migraine preventive treatment with calcitonin gene-related peptide (CGRP) pathway inhibitors, such as erenumab and others, may theoretically result in cardiovascular effects due to a lack of compensatory vasodilation with CGRP pathway inhibition.

METHODS

In this retrospective observational cohort study, we estimated the unadjusted cumulative risk (CR) of new-onset hypertension, acute myocardial infarction (MI), or stroke among patients with migraine newly treated with erenumab, other anti-CGRP pathway monoclonal antibodies (mAbs), standard oral preventive medications, and onabotulinumtoxinA using data from the MarketScan® Commercial and Medicare Supplemental medical claims database. Comparative analyses to assess the relative risk (RR) of vascular events were gated on the comparability of treatment groups with respect to baseline demographics and clinical characteristics. Potential bias due to unmeasured confounding was evaluated via negative control outcome (NCO) analyses. Confounding based on measured covariates and differential informative censoring were addressed with inverse probability weights.

RESULTS

A total of 108,019 new users of migraine preventive medications were included. Unadjusted CR (95% confidence interval [CI]) of hypertension at 12 months of treatment was: erenumab, 9.34% (8.79-9.89%); other anti-CGRP pathway mAbs, 9.42% (8.92-9.92%); standard oral preventive medications, 9.09% (8.77-9.41%); and onabotulinumtoxinA, 9.10% (8.39-9.81%). NCO analyses identified minimal concerns related to unmeasured confounding in erenumab versus other mAbs and erenumab versus onabotulinumtoxinA comparisons. Adjusted RRs (95% CIs) of acute MI and stroke, respectively, at 36 months of treatment were 1.02 (0.45-1.59) and 0.90 (0.56-1.25) for erenumab versus other mAbs and 0.87 (0.19-1.55) and 0.97 (0.42-1.52) for erenumab versus onabotulinumtoxinA.

CONCLUSIONS

In this analysis of the MarketScan medical claims database, we found no difference in the risk of vascular events in patients treated with erenumab versus other anti-CGRP pathway mAbs or onabotulinumtoxinA.

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.

A 2-Part, Open-Label, Phase 1 Bioequivalence and Food-Effect Study of Ubrogepant in Healthy Adult Participants

This Phase 1 study of ubrogepant was conducted to establish the bioequivalence (BE) of the 50- and 100-mg to-be-marketed (TBM) tablet formulations with the clinical trial (CT) 100-mg tablet formulation and evaluate the food effect on the bioavailability of the 100-mg TBM tablet. This 2-part study enrolled healthy participants aged 18-45 years. Part A assessed BE following a single dose of TBM versus CT tablets. Part B evaluated the impact of a high-fat meal on ubrogepant pharmacokinetics. Safety and tolerability were assessed along with standard pharmacokinetic parameters. In Part A (n  =   47), the geometric mean ratio and 90% confidence intervals for maximum plasma drug concentration, area under the plasma concentration-time curve (AUC) from time zero to time t, and AUC from time zero to infinity for the TBM and CT formulations demonstrated BE. The time to peak exposure was the same for both formulations. In Part B (n  =  18), a high-fat meal delayed time to peak exposure and reduced maximum plasma drug concentration by 22%, with no effect on AUC. The occurrence of treatment-emergent adverse events was low, and the majority were mild. Ubrogepant TBM and CT tablets (1 × 100 mg or 2 × 50 mg) were bioequivalent under fasted conditions, and a high-fat meal had no clinically relevant effect on the bioavailability of the TBM tablet formulation.

Cerebrospinal Fluid Concentrations of Calcitonin Gene Related Peptide in Dogs With Chiari-Like Malformation

BACKGROUND

The biomarker Calcitonin Gene-Related Peptide (CGRP) is elevated in human conditions associated with neuropathic pain, but has not yet been studied in Cavalier King Charles Spaniels (CKCS) with Chiari-like malformation (CM).

HYPOTHESIS/OBJECTIVES

Cavalier King Charles Spaniels with clinical signs of CMSM would have higher CSF concentrations of CGRP than asymptomatic CKCS. Our aim was to measure CSF CGRP concentrations in CKCS with and without clinical signs of CMSM.

ANIMALS

Twenty-nine CKCS drawn from research and clinical cases underwent quantification of pain and scratching, a brain and spinal cord MRI, and lumbar CSF collection.

METHODS

This was a prospective study with both normal and clinically affected CKCS recruited. The CSF concentration of CGRP (C-CGRP) was measured using an ELISA assay. Dogs were grouped by the presence of SM, pain, and scratching, and concentrations of C-CGRP were compared between groups using Wilcoxon Rank Sum. The concentration of C-CGRP, pain score, and SM diameter were evaluated using linear regression.

RESULTS

Concentration of C-CGRP was significantly higher in painful dogs (median 116.1, range: 11.6-238.3 pg/mL) as compared to non-painful dogs (median 77.7 pg/mL, range 0-266.2 pg/mL; p = 0.0124). No significant difference in C-CGRP concentration was noted between dogs with (median 99.3, range 0-226.6 pg/mL) and without (median 102.2, range 6.0-266.2 pg/mL) SM (p = 0.305).

CONCLUSIONS AND CLINICAL IMPORTANCE

Cerebrospinal fluid CGRP concentration is elevated in CKCS exhibiting pain regardless of the presence of SM. CGRP might contribute to neuropathic pain in CMSM and could be a target for therapeutic intervention.

Amylin and the amylin receptors in migraine: Is there another pathway to target?

Here, we review the available evidence implicating amylin in migraine, its relationship with calcitonin gene-related peptide (CGRP) and its potential utility as a therapeutic target. The pathophysiology of migraine is currently better understood and the role of CGRP is key. Treatments targeting this pathway have been successful and migraine is a complex disorder, with so many molecules being implicated. Amylin, as for CGRP, is part of the calcitonin/CGRP peptide family. Some therapies intended to block the CGRP pathway can also target amylin receptors. Similar to CGRP, amylin can trigger migraine attacks in a provocation study. Amylin plasma levels have been highlighted as a potential migraine biomarker in one study in migraine patients. Moreover, some preclinical studies in rodents have also discussed sex differences. Comprehending the distinct and overlapping mechanisms between amylin and CGRP signalling could develop further our understanding of migraine pathophysiology. In summary, this review reveals, through initial studies, that targeting the amylin pathway may have a potential role as a novel treatment option for those who may not respond to other treatments, or as a better alternative.

Targeting PACAP: Beyond Migraine to Cluster, Menstrual, and Post-traumatic Headaches

The pituitary adenylate cyclase-activating peptide (PACAP) pathway is a critical focus in the pathophysiology of several headache disorders. PACAP influences headache pathophysiology through interactions with distinct receptors (PAC1, VPAC1, and VPAC2) and pathways linked to neurovascular and hormonal regulation. Evidence supports its role in the modulation of trigeminal and parasympathetic systems, implicated in cluster headaches and menstrual migraine, and its involvement in sensitizing pain pathways post trauma in post-traumatic headaches. Early clinical trials targeting PACAP signaling show promise, with one study demonstrating efficacy in migraine prophylaxis. This narrative review synthesizes current evidence while addressing gaps in understanding PACAP's precise mechanisms. Future research should prioritize expanding the scope of PACAP-focused investigations across diverse headache types, aiming to establish it as a therapeutic target for several headache disorders. Success in ongoing and future trials could redefine headache management for millions of underserved patients worldwide.

Calcitonin gene-related peptide in newly diagnosed idiopathic intracranial hypertension: a prospective, cross-sectional, case-control study of cerebrospinal fluid and plasma

BACKGROUND

Calcitonin Gene-Related Peptide (CGRP) is involved in migraine pain signaling, and blockage hereof is effective in migraine treatment. Headache in idiopathic intracranial hypertension (IIH) is often migraine-like but the underlying mechanisms are not understood. We report levels of CGRP in plasma and cerebrospinal fluid (CSF) of patients with newly diagnosed IIH to elucidate CGRP involvement in the pathogenesis of headache in IIH.

METHOD

We consecutively enrolled patients suspected of having IIH in a prospective cohort at two Danish tertiary headache centers. Patients are confirmed to have IIH or disproven of it (non-IIH). We included non-IIH with primary headache disorders as headache controls to IIH cases. We also recruited sex-, age- and BMI-matched healthy controls (HC). All participants had CSF and blood drawn and CGRP was analyzed using a validated radioimmunoassay. CSF plasma-ratios were calculated. Between-group levels were compared with ANOVA or Kruskal-Walli's test. In sub-analyses we restricted comparison of HC to non-IIH/IIH with chronic migraine; we also compared IIH with versus without headache. We correlated CGRP to lumbar opening pressure (OP), and BMI, and assessed the correlation between CGRP in plasma and CSF. Generalized or linear regression was applied to adjust for confounding by BMI, age, and active smoking.

RESULTS

Comparing 97 patients with IIH, 52 non-IIH, and 37 HC, we found no between-group differences in CGRP levels in plasma (p = 0.78), CSF (p = 0.79), or in CSF:plasma-ratio (p = 0.13). Adjusting for BMI, age, and smoking yielded similar results. CGRP levels were neither associated with having a migraine phenotype or chronic headache, nor with having any headache versus no headache in IIH. CGRP in plasma correlated with CGRP in CSF (p < 0.0001). CGRP did not correlate with OP or BMI.

CONCLUSION

CGRP levels in plasma and CSF and their ratios were comparable in IIH, non-IIH patients with headache, and sex-, age-, and BMI-matched HC. CGRP in plasma correlated with CGRP in CSF. Due to methodology, we probably measured basal resting CGRP. The role of CGRP in IIH-headache needs further clarification. A headache preventive effect in IIH of anti-CGRP targeted therapy remains a relevant unexplored area.

Migraine treatment with CGRP monoclonal antibodies: patient evaluation of a mandatory treatment holiday in Belgium

BACKGROUND

Monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway have emerged as a promising preventive treatment for migraine. In Belgium, patients receiving these antibodies must adhere to a mandatory treatment holiday of three months. This study investigated the patients' experiences during this treatment holiday.

METHODS

A prospective study was conducted among 243 patients from nine headache clinics in Belgium receiving treatment with erenumab, fremanezumab or galcanezumab. Participants completed a structured questionnaire during their yearly follow-up visit after the treatment holiday. The questionnaire assessed the subjective migraine evolution and anxiety levels, and perceived usefulness of the treatment holiday.

RESULTS

The majority of patients (86.0%) reported worsening of migraine symptoms during the treatment holiday, 59.4% of them experiencing deterioration already within the first month. For 5.9% of patients, this occurred beyond the 3-month mandatory holiday period, delaying treatment resumption. Improvement was reported by 3.0% of patients, while 11.0% experienced no change. Anxiety surrounding the treatment holiday was reported by 45.0% of participants, with 18.6% experiencing very high levels of anxiety. A significant association was found between anxiety and subjective migraine deterioration (p = 0.012). Nearly half (49.1%) of the respondents found the drug holiday overall useful in gaining insight into the need for continued treatment, 22.6% considered it even very useful.

CONCLUSION

A rigid, mandatory treatment holiday of two to three months poses significant challenges for a substantial subset of patients, leading to rapid migraine deterioration and increased anxiety. The observed association between migraine deterioration and anxiety highlights the need for patient education strategies. Policy makers should consider these findings to develop more flexible, patient-centered treatment approaches that optimize outcomes.

Calcitonin gene-related peptide-targeted therapy in migraine: current role and future perspectives

Almost 40 years ago, the discovery of the vasoactive neuropeptide calcitonin gene-related peptide (CGRP) and its role in migraine pathophysiology ushered in a new era in migraine treatment. Since 2018, monoclonal antibodies (mAbs) targeting the CGRP pathway are available for migraine prevention. The approval of these drugs marks a pioneering development, as they are the first pharmacological agents specifically tailored for migraine prevention. Introduction of these agents contrasts the historical reliance on traditional preventive medications initially formulated for other indications and later repurposed for migraine therapy. Although the emergence of evidence on the efficacy and safety of CGRP-targeted mAbs has raised the bar for treatment success in migraine, their efficacy in other headache entities, such as cluster headache, is low to moderate. Small-molecule CGRP receptor antagonists called gepants have also been proven to be effective both as acute and preventive migraine treatments. Furthermore, these agents have bridged the traditional categories of acute and preventive treatment strategies. Short-term prevention and treatment during the prodromal phase of migraine represent emerging strategies enabling clinicians to develop treatment approaches designed to meet changing patient needs; however, these strategies still require more formal evidence. Although solid data have been gathered, further research concerning the efficacy and long-term safety of drugs targeting the CGRP pathway and robust pharmacoeconomic evaluations are needed. Finally, randomised withdrawal and switching studies would facilitate the formulation of evidence-based guidance for the discontinuation of and switching between drugs targeting the CGRP pathway.

No change in interictal plasma and salivary CGRP levels in individuals with vestibular migraine corresponding to episodic migraine

BackgroundFew studies have examined plasma calcitonin gene-related peptide (CGRP) levels in individuals with vestibular migraine (VM), with inconsistent findings. Additionally, salivary CGRP levels in VM have not been reported.MethodsInterictal plasma and salivary CGRP levels were measured using an enzyme-linked immunosorbent assay in participants with VM corresponding to episodic migraine (VM, n = 81), chronic migraine without vestibular symptoms (CM, n = 73) and healthy controls (HC, n = 59).ResultsPlasma CGRP levels in VM with episodic migraine participants were significantly lower than those in participants with CM (median = 37.1 pg/mL, interquartile range (IQR) = 22.4-60.4 pg/mL vs. median = 74.6 pg/mL, IQR  = 49.6-101.6 pg/mL; p < 0.001) but did not significantly differ from levels in HC. Similarly, salivary CGRP levels were also significantly lower in VM compared to CM (median = 54.5 pg/mL, IQR = 37.0-83.4 pg/mL vs. median = 72.0 pg/mL, IQR  = 56.5-96.2 pg/mL; p = 0.036), with no significant difference observed between VM and HC. Receiver operating characteristic analysis showed that plasma CGRP levels effectively differentiated CM from VM corresponding to episodic migraine, achieving an area under the curve of 0.88. No significant correlations were found between plasma or salivary CGRP levels and clinical features of CM and VM.ConclusionsInterictal plasma and salivary CGRP levels are unlikely to serve a biomarkers for VM.

Evidence-based review and frontiers of migraine therapy

BACKGROUND

Cyclic vomiting syndrome (CVS) is identified as one of the "episodic syndromes that may be associated with migraine," along with benign paroxysmal torticollis, benign paroxysmal vertigo, and abdominal migraine. It has been proposed that CVS and migraine may share pathophysiologic mechanisms of hypothalamic activation and altered dopaminergic signaling, and impaired sensorimotor intrinsic connectivity. The past decade has brought groundbreaking advances in the treatment of migraine and other headache disorders. While many of these therapies have yet to be studied in episodic syndromes associated with migraine including CVS and abdominal migraine, the potential shared pathophysiology among these conditions suggests that use of migraine-specific treatments may have a beneficial role even in those for whom headache is not the primary symptom.

PURPOSE

This manuscript highlights newer therapies in migraine. Calcitonin gene-related peptide (CGRP) and its relation to migraine pathophysiology and the therapies that target the CGRP pathway, as well as a 5HT1F receptor agonist and neuromodulation devices used to treat migraine are briefly discussed as they may potentially prove to be useful in the future treatment of CVS.

Differential Regulation of Nav1.1 and SCN1A Disease Mutant Sodium Current Properties by Fibroblast Growth Factor Homologous Factors

Fibroblast growth factor homologous factors (FHFs) regulate the activity of several different voltage-gated sodium channels (Navs). However, more work is needed to determine how specific FHF isoforms and variants affect the properties of different Nav isoforms. In addition, it is not known if FHFs can differentially modulate the properties of Nav variants associated with disease. Here, we investigated the effects of FHF2A and FHF2B on Nav1.1 properties as well as on a familial hemiplegic migraine 3 (FHM3) causing mutation in this channel, F1774S. We found that FHF2A, but not 2B, induced prominent long-term inactivation (LTI) in the wild-type (WT) Nav1.1. Interestingly, FHF2A induced LTI in the F1774S FHM3 mutant channel to a greater extent than in the WT. Furthermore, persistent currents caused by the F1774S mutation were attenuated by the co-expression of FHF2A, leading to a possible rescue of the mutant channel phenotype. By contrast, the P1894L mutation, which is associated with epilepsy and mild intellectual disability, greatly attenuated the LTI induced by FHF2A. Overall, our data show for the first time that FHF2A might be a significant modulator of Nav1.1 that can differentially modulate the impact of Nav1.1 disease-associated mutations.

Disproportionality analysis of Raynaud's phenomenon associated with calcitonin gene-related peptide inhibitors using the Food and Drug Administration adverse event reporting system

Raynaud's phenomenon is a vascular condition characterized by episodic vasoconstriction, and recent reports suggest a potential link between calcitonin gene-related peptide (CGRP) inhibitors, used for migraine treatment, and the onset of this condition. This study evaluated the association between CGRP inhibitors and Raynaud's phenomenon using data from the FDA Adverse Event Reporting System (FAERS). A retrospective analysis of adverse events from the approval year of each drug through August 2023 was conducted. Disproportionality was assessed using Reporting Odds Ratios (ROR) and Information Components (IC), with significant signals of disproportionate reporting (SDR) identified by a lower 95% confidence interval (CI) for ROR > 1.0 and IC > 0. Intra-class and inter-class analyses were conducted to compare SDRs among CGRP inhibitors and other migraine therapies, including triptans, beta-blockers, and anticonvulsants. CGRP inhibitors demonstrated significant SDRs for Raynaud's phenomenon (ROR 19.12; 95% CI 15.44-23.69), with rimegepant, ubrogepant, and atogepant showing particularly strong signals. Intra-class analysis revealed a significant SDR only for galcanezumab (ROR 2.01; 95% CI 1.28-3.17). Inter-class analysis indicated significant SDRs for CGRP inhibitors compared to beta-blockers, anticonvulsants, and celecoxib, but not triptans. These findings underscore the importance of ongoing pharmacovigilance and further research to validate these associations and ensure patient safety.

Capsaicin and TRPV1: A Novel Therapeutic Approach to Mitigate Vascular Aging

Vascular aging and its associated diseases represent a principal cause of mortality among the global elderly population, making the mitigation of vascular aging a significant aspiration for humanity. This article explores the intersection of nature and health, focusing on the role of the natural plant, pepper, and its principal bioactive compound, capsaicin, in combating vascular aging. By examining molecular and cellular mechanisms as well as phenotypic alterations in blood vessels, we offer a comprehensive review of the effects of capsaicin and its receptor, transient receptor potential vanilloid 1 (TRPV1), within vascular aging. We propose that capsaicin may serve as the medication with the potential to slow the progress of vascular aging and could constitute a new strategy to treat vascular aging related disease.

Chronification of migraine sensitizes to CGRP in male and female mice

BACKGROUND

Acute therapies targeting calcitonin gene-related peptide (CGRP) for episodic migraine (EM) demonstrate efficacy in women, but evidence of efficacy in men remains to be established. By contrast, CGRP targeting therapies for migraine prevention are effective in both men and women with frequent EM or chronic migraine (CM). Preclinical studies have shown that supradural application of CGRP preferentially produces migraine-like pain behaviors in female rodents. We hypothesized that, in male mice, increased frequency of migraine-like pain may sensitize to nociceptive effects of CGRP and this might be associated with altered expression of CGRP in trigeminal ganglion (TG) neurons and/or in their dural projections.

METHODS

CM was modeled in male and female mice by repeated administration of nitroglycerin (NTG). Medication overuse headache (MOH), a form of CM, was modeled by repeated daily administration of sumatriptan. Following resolution of transient cutaneous allodynia (CA) elicited by NTG or sumatriptan, mice received a sex specific subthreshold dose of supradural CGRP that does not elicit CA in naïve male or female mice, and CA was evaluated. CGRP-positive cell bodies in the ophthalmic V1 region of the trigeminal ganglion (TGV1) and CGRP-positive nerve fibers innervating the dura mater were assessed.

RESULTS

Supradural administration of 1 pg of CGRP produced migraine-like pain behaviors in female, but not male, mice; a ten-fold lower dose was established as subthreshold in naïve female mice. Repeated NTG or sumatriptan produced transient CA in both female and male mice that resolved within 8-11 days after treatment cessation. Following resolution of CA, previously subthreshold doses of CGRP elicited CA in CM and MOH models in mice of both sexes, with no effects observed in vehicle treated controls. A higher number of CGRP-positive neurons in the TGV1 was found in naïve female compared to male mice. The number of CGRP-positive TGV1 neurons was increased in both sexes following repeated NTG. Similar nerve fiber density was observed in the dura mater of male and female mice and no differences were detected following repeated NTG.

CONCLUSIONS

As previously reported, CGRP produced female-selective migraine-like pain behaviors in naïve mice. Consistent with behavioral effects, female mice demonstrated a higher number of CGRP-positive cells in the TGV1. These findings appear relevant to clinical observations of female efficacy of CGRP-receptor antagonists for acute treatment in EM patients. In models of CM or MOH that are characterized by increased frequency of migraine-like pain, previously subthreshold doses of supradural CGRP now elicited migraine-like nociceptive behaviors in mice of both sexes. The increased pain responses were accompanied by increased number CGRP positive TGV1 cells in the NTG model in both female and male mice. These data suggest that increased frequency of migraine promotes physiological changes including increased expression of TGV1 CGRP along with sensitization to CGRP-induced nociception in both males and females. Thus, as EM transforms to CM, CGRP-dependent mechanisms may become increasingly important, consistent with observations of efficacy of CGRP targeting therapies for migraine prevention in both men and women. Our results also suggest the possibility of enhanced efficacy of CGRP-receptor antagonists for the acute treatment of migraine in men as migraine frequency increases.

Meningeal K ATP channels contribute to behavioral responses in preclinical migraine models

ABSTRACT

Human experimental studies have shown that levcromakalim, an ATP-sensitive potassium (K ATP ) channel opener, induces migraine attacks in people with migraine but not in healthy volunteers. However, the exact site of action for K ATP channels in migraine pathophysiology remains unclear. This study investigates the role of these channels in the meninges in eliciting behavioral hypersensitivity responses in mice. The effects of K ATP channel signaling were assessed using preclinical migraine models induced by repetitive stress or dural stimulation. Prolactin, CGRP, sodium nitroprusside (SNP), and K ATP channel openers or blockers were administered systemically or onto the dura of mice followed by behavioral testing using periorbital von Frey or facial grimace measurements. Repetitive stress sensitized mice to a normally subthreshold systemic dose of levcromakalim. The K ATP blocker glibenclamide significantly reduced responses to systemic SNP following repetitive stress. In naive mice, direct dural application of levcromakalim or SNP elicited periorbital hypersensitivity. Responses to dural levcromakalim were inhibited by coinjection with glibenclamide or sumatriptan. By contrast, injection of levcromakalim in the periorbital skin did not induce hypersensitivity. Moreover, repetitive stress sensitized mice to dural injection of normally subthreshold doses of levcromakalim or SNP. Finally, dural coinjection of glibenclamide inhibited periorbital hypersensitivity induced by CGRP or prolactin in female mice. These studies demonstrate that the meninges can be one site of action for the migraine-triggering effects of K ATP channel openers. They also show that NO donors, CGRP, and prolactin can produce behavioral hypersensitivity through opening of K ATP channels in the meninges.

Cardiovascular Safety of Anti-CGRP Monoclonal Antibodies in Older Adults or Adults With Disability With Migraine

Importance

Monoclonal antibodies (mAbs) targeting calcitonin gene-related peptide (CGRP) or its receptor (anti-CGRP mAbs) offer effective migraine-specific preventive treatment. However, concerns exist about their potential cardiovascular risks due to CGRP blockade.

Objective

To compare the incidence of cardiovascular disease (CVD) between Medicare beneficiaries with migraine who initiated anti-CGRP-mAbs vs onabotulinumtoxinA in the US.

Design, Setting, and Participants

This retrospective, sequential cohort study was conducted among a nationally representative population-based sample of Medicare claims from May 2018 through December 2020. Data analysis was performed from August to December 2023. This study included fee-for-service Medicare beneficiaries aged 18 years or older with migraine who initiated either anti-CGRP mAbs or onabotulinumtoxinA. Beneficiaries who had a history of myocardial infarction (MI), stroke, cluster headache, malignant cancer, or hospice service within a 1-year baseline period prior to treatment initiation were excluded. To minimize channeling bias from new drug introductions and time-related bias due to the COVID-19 pandemic, 5 cohorts were established, representing sequential 6-month calendar intervals based on the initial prescription or date of index anti-CGRP mAbs or onabotulinumtoxinA use.

Exposure

Anti-CGRP mAbs vs onabotulinumtoxinA.

Main Outcomes and Measures

The primary outcome was time to first MI or stroke. Secondary outcomes included hypertensive crisis, peripheral revascularization, and Raynaud phenomenon. The inverse probability of treatment-weighted Cox proportional hazards models were used to compare outcomes between the 2 treatment groups.

Results

Among 266 848 eligible patients with migraine, 5153 patients initiated anti-CGRP mAbs (mean [SD] age, 57.8 [14.0] years; 4308 female patients [83.6%]) and 4000 patients initiated onabotulinumtoxinA (mean [SD] age, 61.9 [13.7] years; 3353 female patients [83.8%]). Use of anti-CGRP mAbs was not associated with an increased risk of composite CVD events (adjusted hazard ratio [aHR], 0.88; 95% CI, 0.44-1.77), hypertensive crisis (aHR, 0.46; 95% CI, 0.14-1.55), peripheral revascularization (aHR, 1.50; 95% CI, 0.48-4.73), or Raynaud phenomenon (aHR, 0.75; 95% CI, 0.45-1.24) compared with onabotulinumtoxinA. Subgroup analyses by age group and presence of established non-MI or stroke CVD showed similar findings.

Conclusions and Relevance

In this cohort study, despite initial concerns regarding the cardiovascular effects of CGRP blockade, anti-CGRP mAbs were not associated with an increased risk of CVD compared with onabotulinumtoxinA among adult Medicare beneficiaries with migraine, who were predominantly older adults or individuals with disability. Future studies with longer follow-up periods and in other populations are needed to confirm these findings.

Assessment of pharmacokinetic and pharmacodynamic interactions between zavegepant and sumatriptan: A phase 1, randomized, placebo-controlled study in healthy adults

OBJECTIVE

To evaluate the pharmacodynamic (PD) and pharmacokinetic (PK) interactions between zavegepant and sumatriptan in healthy adults.

BACKGROUND

Zavegepant is a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist administered as a nasal spray approved in the United States for the acute treatment of migraine. Triptans, including sumatriptan, are a different class of drugs for acute migraine treatment and are associated with a risk of increased blood pressure (BP). Hence, it is important to study the drug-drug interactions between zavegepant and sumatriptan due to potential coadministration in clinical settings.

METHODS

This was a Phase 1, single-center, partially blind, randomized, placebo-controlled, single-arm study. Eligible participants were males aged ≥ 18 and ≤ 40 years or females aged ≥ 18 and ≤ 50 years. On Day 1, participants received sumatriptan 2 × 6 mg subcutaneous injections (1 h apart) and were then randomized (6:1 ratio) to receive zavegepant 2 × 10 mg nasal spray (1 in each nostril) or placebo on Days 2 and 3. On Day 4, zavegepant or placebo was coadministered with sumatriptan after the second sumatriptan injection. BP, PK, and safety were evaluated at pre-specified time points.

RESULTS

Forty-two participants enrolled in the study received at least one dose of any treatment and were included in the safety analyses. Forty-one participants who completed the study were included in the BP and PK analyses. The mean (standard deviation) time-weighted average (TWA) of mean arterial pressure (MAP [sumatriptan + zavegepant 87.2 (6.8) vs. sumatriptan 86.9 (6.0)]), diastolic BP (DBP [sumatriptan + zavegepant 72.3 (6.8) vs. sumatriptan 72.1 (6.2)]), and systolic BP (SBP [sumatriptan + zavegepant 116.8 (10.2) vs. sumatriptan 116.2 (8.6)]) did not change following zavegepant and sumatriptan coadministration on Day 4 compared to sumatriptan alone on Day 1. Statistical comparisons of the TWA of MAP, DBP, and SBP between sumatriptan and zavegepant coadministration and sumatriptan alone were similar; the differences observed were 0.04 mmHg for MAP (90% confidence interval [CI]: -0.69, 0.77 mmHg), 0.00 mmHg for DBP (90% CI: -0.76, 0.76 mmHg), and 0.33 mmHg for SBP (90% CI: -0.97, 1.63 mmHg). Sumatriptan PK after sumatriptan and zavegepant coadministration versus sumatriptan alone was similar; the comparison ratios were 102.5% (90% CI: 100.7%, 104.2%) for AUC0-inf and 104.1% (90% CI: 98.0%, 110.6%) for Cmax. A small difference in zavegepant PK exposure after sumatriptan and zavegepant coadministration versus zavegepant alone was not considered clinically relevant: the comparison ratios were 112.4% (90% CI: 103.4%, 122.3%) for AUC0-24 and 96.7% (90% CI: 88.9%, 105.2%) for Cmax. Overall, 90% (38/42) of participants experienced ≥ 1 treatment-emergent adverse event that was mild or moderate in severity. All treatments were generally safe and well tolerated.

CONCLUSION

Coadministration of zavegepant with sumatriptan was safe and without PD or PK interactions in healthy adults.

Clinical Pharmacokinetics of Atogepant in Healthy Japanese and White Adults

INTRODUCTION

Atogepant is a calcitonin gene-related peptide receptor antagonist approved for the preventive treatment of migraine in adults in the USA, EU, and several other countries. The objectives of this study were to evaluate the pharmacokinetics (PK) and dose proportionality of atogepant in healthy Japanese participants, evaluate the safety and tolerability of atogepant in Japanese participants, and explore the differences in the PK and safety of atogepant in Japanese vs white participants.

METHODS

A total of 50 participants (40 Japanese and 10 white) were enrolled into five cohorts; Japanese cohorts were randomized in a 4:1 ratio to atogepant (10 mg, 30 mg, or 60 mg daily dosing and 60 mg twice daily) or placebo. The white participants were randomized to atogepant (60 mg twice daily) or placebo. Doses were administered on day 1 and days 3-8, with those on days 1 and 8 administered after an overnight fast.

RESULTS

In Japanese participants, atogepant exposure increased with dose, and there was no accumulation with once-daily dosing and minimal (~ 20%) accumulation with twice-daily dosing. Atogepant steady-state exposure appeared to be marginally lower in Japanese participants compared with white participants and was well tolerated. There were no treatment-related adverse events, serious adverse events, clinically significant changes in vital signs, or signs of suicidal ideation or behaviors.

CONCLUSION

Atogepant exposure increased with dose in healthy Japanese participants and was well tolerated within the dose range tested.

The influence of pharmacodynamics and pharmacokinetics on the antimigraine efficacy and safety of novel anti-CGRPergic pharmacotherapies: a narrative review

INTRODUCTION

Migraine is a complex disorder, and its etiology is not yet fully understood. In the last 40 years, calcitonin gene-related peptide (CGRP) has been central to the understanding of migraine pathophysiology, leading to the development of new molecules targeting the CGRPergic system. These new molecules, such as gepants and monoclonal antibodies, are effective, well-tolerated, and safe, and are approved for clinical use.

AREAS COVERED

By searching multiple electronic scientific databases, this narrative review examined: (i) the role of CGRP in migraine; and (ii) the current knowledge on the effects of CGRPergic antimigraine pharmacotherapies, including a brief analysis of their pharmacodynamic and pharmacokinetic characteristics.

EXPERT OPINION

Current anti-CGRPergic medications, although effective, have limitations, such as side effects and lack of antimigraine efficacy in some patients. The existence of patients with medication-resistant migraine may be due to the: (i) complex migraine pathophysiology, in which several systems appear to be deregulated before, during, and after a migraine attack; and (ii) pharmacodynamic and pharmacokinetic properties of antimigraine medications. As envisioned here, although seminal studies support the notion that CGRP plays a key role in migraine headache, the dysfunction of CGRPergic transmission does not seem to be relevant in all cases.

CaV3.2 T-type calcium channels contribute to CGRP- induced allodynia in a rodent model of experimental migraine

BACKGROUND

Migraine is a painful neurological syndrome characterized by attacks of throbbing headache, of moderate to severe intensity, which is associated with photo- and phono- sensitivity as well as nausea and vomiting. It affects about 15% of the world's population being 2-3 times more prevalent in females. The calcitonin gene-related peptide (CGRP) is a key mediator in the pathophysiology of migraine, and a significant advance in the field has been the development of anti-CGRP therapies. The trigeminal ganglion (TG) is thought to be an important site of action for these drugs. Moreover, experimental migraine can be induced by CGRP injection in the TG. The signaling pathway induced by CGRP in the TG is not fully understood, but studies suggest that voltage-gated calcium channels contribute to CGRP effects relevant to migraine.

OBJECTIVE

We hypothesised that CGRP injection in the TG enhances CaV3.2 T-type calcium channel currents to contribute to the development of periorbital mechanical allodynia.

RESULTS

A Co-Immunoprecipitation assay in tsA-201 cells revealed that CaV3.2 channels form a complex with RAMP-1, a component of the CGRP receptor. Constitutive CGRPR activity was able to inhibit CaV3.2 channels and induce a depolarizing shift in both activation and inactivation curves. Incubation of TG neurons with CGRP increased T-type current density by ~ 3.6 fold, an effect that was not observed in TG neurons from CaV3.2 knockout mice. Incubation of TG neurons with Z944, a pan T-type channel blocker, resulted in an approximately 80% inhibition of T-type currents. In vivo, this treatment abolished the development of periorbital mechanical allodynia induced by CGRP in male and female mice. Likewise, CaV3.2 knockout mice did not develop periorbital mechanical allodynia after intraganglionic CGRP injection. Finally, we demonstrated that the CGRP effect depends on the activation of its canonical GPCR, followed by protein kinase A activation.

CONCLUSION

The present study suggests that CGRP modulates CaV3.2 in the TG, an effect possibly mediated by the canonical CGRP receptor and PKA activation. The increase in T-type currents in the TG may represent a contributing factor for the initiation and maintenance of the headache pain during migraine.

Bimodal functions of calcitonin gene-related peptide in the brain

AIMS

Calcitonin gene-related peptide (CGRP) is a pluripotent neuropeptide crucial for maintaining vascular homeostasis, yet its full therapeutic potential remains incompletely exploited. Within the brain, CGRP demonstrates a distinct bimodal effect, contributing to neuroprotection in ischemic conditions while inducing neuronal sensitization and inflammation in non-ischemic settings. Despite extensive research on CGRP, the absence of a definitive determinant for this observed dichotomy has limited its potential for therapeutic applications in the brain. This review examines the effects of CGRP in both physiological and pathological conditions, aiming to identify a unifying factor that could enhance its therapeutic applicability.

MATERIALS AND METHODS

This comprehensive literature review analyzes the molecular pathways associated with CGRP and the specific cellular responses observed in these contexts. Additionally, the review investigates the psychological implications of CGRP in relation to cerebral perfusion levels, aiming to elucidate its underlying factors.

KEY FINDINGS

Reviewing the literature reveals that, elevated levels of CGRP in non-ischemic conditions exert detrimental effects on brain function, while they confer protective effects in the context of ischemia. These encompass anti-oxidative, anti-inflammatory, anti-apoptotic, and angiogenic properties, along with behavioral normalization. Current findings indicate promising therapeutic avenues for CGRP beyond the acute phases of cerebral injury, extending to neurodegenerative and psychological disorders associated with cerebral hypoperfusion, as well as chronic recovery following acute cerebral injuries.

SIGNIFICANCE

Improved understanding of CGRP's bimodal properties, alongside advancements in CGRP delivery methodologies and brain ischemia detection technologies, paves the way for realizing its untapped potential and broad therapeutic benefits in diverse pathological conditions.

Immunohistochemical Identification of Sensory Neuropeptides Calcitonin Gene-Related Peptide, Substance P, and Pituitary Adenylate Cyclase-Activating Polypeptide in Efferent Vestibular Nucleus Neurons

INTRODUCTION

The efferent vestibular system (EVS) originates in brainstem efferent vestibular nuclei (EVN) and modifies afferent vestibular signals at their source, in peripheral vestibular organs. Recent evidence suggests that EVS is also involved in the development of motion sickness symptoms, including vertigo and nausea, but the underlying mechanism is unknown. One possible link between EVN and motion sickness symptoms is through the neuropeptide calcitonin gene-related peptide (CGRP). CGRP often co-exists with substance P and pituitary adenylate cyclase-activating polypeptide (PACAP), two neuropeptides with similar vasodilatory effects. Collectively, these sensory neuropeptides have been associated with vestibular migraine pathophysiology and motion sickness. While CGRP and the fast EVS neurotransmitter, acetylcholine (ACh), have previously been identified in EVN neurons and their peripheral terminals, the presence of substance P and PACAP in the EVN has not yet been described.

METHODS

We used fluorescent immunohistochemistry combined with confocal microscopy to examine the distribution of these three neuropeptides in the mouse EVN. In transgenic choline acetyltransferase (ChAT)-gCaMP6f mice, EVN neurons were positively identified using the fluorescent expression of gCaMP6f. In wild-type C57/BL6 mice, EVN neurons were confirmed using ChAT immunolabelling.

RESULTS

Consistent with previous studies, CGRP was labelled in a subset of cholinergic EVN neurons. Additionally, we also show evidence for substance P and PACAP expression in EVN of transgenic and wild-type mice.

CONCLUSION

The presence of CGRP, substance P, and PACAP in EVN neurons suggests a complex peptidergic modulation of cholinergic signalling, whose release into local blood vessels may contribute to motion sickness symptoms.

Deconvoluting zavegepant drug-drug interactions: A phase I study to evaluate the effects of rifampin and itraconazole on zavegepant pharmacokinetics

Zavegepant is a calcitonin gene-related peptide receptor antagonist for acute migraine treatment. This Phase I, open-label, fixed-sequence study evaluated the effects of itraconazole (a strong cytochrome P450 3A4 [CYP3A4] and P-glycoprotein [P-gp] inhibitor) on the pharmacokinetics of intranasal/oral zavegepant and the effects of rifampin (a strong inducer of CYP3A4 and P-gp; and an inhibitor of organic anion transporting polypeptide 1B3 [OATP1B3]) on oral zavegepant in healthy participants. In the intranasal/oral zavegepant-itraconazole cohort, participants received a single 10-mg dose of zavegepant nasal spray on Day 1, followed by oral zavegepant (50 mg) on Day 3. Itraconazole 200 mg once daily was administered from Days 4 to 12. On Day 7 zavegepant nasal spray and on Day 11 oral zavegepant were coadministered with itraconazole. In the oral zavegepant-rifampin cohort, participants received oral zavegepant (100 mg) on Day 1, rifampin 600 mg once daily on Days 2-10, and rifampin with zavegepant on Day 11. No significant change in zavegepant exposure was observed following coadministration of itraconazole with zavegepant nasal spray. For oral zavegepant coadministered with itraconazole, the area under the curve from 0 to infinity (AUC0-inf) and the maximum observed concentration (Cmax) of oral zavegepant increased by 59% and 77%, respectively. For oral zavegepant coadministered with rifampin, the AUC0-inf and Cmax of oral zavegepant increased by approximately 2.3- and 2.2-fold, respectively. These results suggest that OATP1B3 and intestinal P-gp are the more prominent pathways, as opposed to CYP3A4, for a zavegepant drug-drug interaction. Coadministration of OATP1B3 inhibitors with zavegepant nasal spray should be avoided.

Intranasal zavegepant for the acute treatment of migraine

INTRODUCTION

Migraine is a highly prevalent chronic, inherited neurological condition of the brain which carries a significant level of disability. Despite advances, there is an unmet need for more effective therapies.

AREAS COVERED

Zavegepant nasal spray is a recent therapeutic option which acts as a calcitonin gene-related peptide receptor antagonist. The objective is to review the efficacy, safety, and additional results of the most recent trials investigating intranasal zavegepant for the acute treatment of migraine with or without aura. The authors searched PubMed using the keywords 'zavegepant,' 'Zavzpret,' 'migraine,' 'calcitonin gene-related peptide,' 'CGRP receptor antagonists.' This article covers Phase 1, Phase 2/3, and Phase 3 randomized, double-blind, placebo-controlled trials to evaluate the efficacy of intranasal zavegepant for treatment of acute migraine attacks.

EXPERT OPINION

Intranasal zavegepant is an efficacious, safe, and tolerable anti-migraine drug based on clinical trials and clinical experience. It is especially useful for patients who experience attacks of sudden onset, those with nausea or vomiting, or a high cardiovascular risk burden. Dysgeusia was common; future studies are needed to better characterize this adverse event. Head-to-head studies are lacking with other migraine-specific therapies; the decision to treat should be patient-centered, with attack-specific characteristics in mind.

Neuroanatomical evidence and a mouse calcitonin gene-related peptide model in line with human functional magnetic resonance imaging data support the involvement of peptidergic Edinger-Westphal nucleus in migraine

ABSTRACT

The urocortin 1 (UCN1)-expressing centrally projecting Edinger-Westphal (EWcp) nucleus is influenced by circadian rhythms, hormones, stress, and pain, all known migraine triggers. Our study investigated EWcp's potential involvement in migraine. Using RNAscope in situ hybridization and immunostaining, we examined the expression of calcitonin gene-related peptide (CGRP) receptor components in both mouse and human EWcp and dorsal raphe nucleus (DRN). Tracing study examined connection between EWcp and the spinal trigeminal nucleus (STN). The intraperitoneal CGRP injection model of migraine was applied and validated by light-dark box, and von Frey assays in mice, in situ hybridization combined with immunostaining, were used to assess the functional-morphological changes. The functional connectivity matrix of EW was examined using functional magnetic resonance imaging in control humans and interictal migraineurs. We proved the expression of CGRP receptor components in both murine and human DRN and EWcp. We identified a direct urocortinergic projection from EWcp to the STN. Photophobic behavior, periorbital hyperalgesia, increased c-fos gene-encoded protein immunoreactivity in the lateral periaqueductal gray matter and trigeminal ganglia, and phosphorylated c-AMP-responsive element binding protein in the STN supported the efficacy of CGRP-induced migraine-like state. Calcitonin gene-related peptide administration also increased c-fos gene-encoded protein expression, Ucn1 mRNA, and peptide content in EWcp/UCN1 neurons while reducing serotonin and tryptophan hydroxylase-2 levels in the DRN. Targeted ablation of EWcp/UCN1 neurons induced hyperalgesia. A positive functional connectivity between EW and STN as well as DRN has been identified by functional magnetic resonance imaging. The presented data strongly suggest the regulatory role of EWcp/UCN1 neurons in migraine through the STN and DRN with high translational value.

Calcitonin-Gene-Related Peptide in Migraine and Tension-Type Headache in Children During Interictal Period

Background/Objectives: Research on calcitonin-gene-related peptide (CGRP) in adult migraine is extensive, but its role in childhood migraine remains unclear. This study aimed to evaluate serum CGRP levels in children experiencing migraine and tension-type headache (TTH) during interictal periods, comparing these levels to age-matched healthy controls. Methods: A total of 66 migraine patients, 59 with TTH, and 53 controls were recruited and stratified by headache onset age: under 7, 7-12, and over 12 years. CGRP levels were quantified using enzyme-linked immunosorbent assay (ELISA). Results: The migraine patients showed significantly higher serum CGRP levels than both the TTH patients and the controls (p < 0.001), with no significant difference between the latter two groups. Among the migraine patients, those without aura (MO) exhibited higher CGRP levels than those with aura (MA). The CGRP levels were lower in the. MA patients whose headaches began between ages 7 and 12 compared to the subjects with MO, while no significant differences were found in the patients whose headaches began after age 12. Conclusions: These findings suggest that elevated serum CGRP is indicative of pediatric migraine, with variations based on migraine type and age of onset. The difference in CGRP in preadolescent migraineurs with and without aura suggest that CGRP levels may vary depending on age and on migraine type.

Understanding the efficacy and tolerability of migraine treatment: a deep dive into CGRP antagonists

INTRODUCTION

The discovery of the role of the calcitonin gene-related peptide (CGPR) in migraine pathogenesis ushered in a new era in headache medicine. This evidence led to the development of small-molecule CGRP receptor antagonists and monoclonal antibodies targeting either CGRP or its receptor.

AREAS COVERED

We will present selected aspects of the role of CGRP in the pathogenesis of migraine, the efficacy of CGRP-targeted treatment, and the still-open questions regarding the practical application of CGRP antagonists in headache medicine.

EXPERT OPINION

CGRP-targeting drugs represent a transformative approach to migraine treatment, offering superior efficacy and tolerability compared to traditional therapies, they are a helpful addition to the treatment arsenal but also have their flaws and require further observation. Their availability provides new hope for migraine patients, particularly those who have not responded adequately to conventional treatments. Future directions for migraine care planning, especially for chronic migraine and medication-overuse headache, should include universal access to these specific and effective forms of therapy to prevent complications from the disease and its negative effects in many aspects of a patient's life.

Benefit-risk assessment based on number needed to treat and number needed to harm: Atogepant vs. calcitonin gene-related peptide monoclonal antibodies

BACKGROUND

To evaluate the benefit-risk assessment of atogepant and calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) vs. placebo based on the number needed to treat (NNT) and the number needed to harm (NNH) in a blended episodic migraine and chronic migraine (EM + CM) population.

METHODS

The NNT was calculated based on achievement of a ≥ 50% reduction in mean monthly migraine days (MMDs) from baseline across 12 weeks. The NNH was calculated using the proportion of participants reporting a discontinuation due to adverse events (AEs). The primary analysis included data from studies of atogepant, erenumab, galcanezumab, eptinezumab and fremanezumab.

RESULTS

In the primary analysis, the calculated NNT for atogepant 60 mg vs. placebo was 4.2 (95% credible interval (CrI) = 3.1-6.7), which was the lowest relative to the CGRP mAbs in the blended EM + CM population. Participants who received atogepant 60 mg or fremanezumab showed the most favorable NNH values (-1010 (95% Crl = 44 to ∞ to number needed to benefit 80) for atogepant) resulting from lower rates of discontinuation due to AEs compared with those receiving placebo.

CONCLUSIONS

Atogepant demonstrated a favorable benefit-risk profile, with NNT and NNH values comparable (not statistically significant) with those of CGRP mAbs across all analyses.

Hallmarks of primary headache: part 1 - migraine

BACKGROUND AND AIM

Migraine is a common disabling conditions which, globally, affects 15.2% of the population. It is the second cause of health loss in terms of years lived with disability, the first among women. Despite being so common, it is poorly recognised and too often undertreated. Specialty centres and neurologists with specific expertise on headache disorders have the knowledge to provide specific care: however, those who do not regularly treat patients with migraine will benefit from a synopsis on the most relevant and updated information about this condition. This paper presents a comprehensive view on the hallmarks of migraine, from genetics and diagnostic markers, up to treatments and societal impact, and reports the elements that identify migraine specific features.

MAIN RESULTS

The most relevant hallmark of migraine is that it has common and individual features together. Besides the known clinical manifestations, migraine presentation is heterogeneous with regard to frequency of attacks, presence of aura, response to therapy, associated comorbidities or other symptoms, which likely reflect migraine heterogeneous genetic and molecular basis. The amount of therapies for acute and for prophylactic treatment is really wide, and one of the difficulties is with finding the best treatment for the single patient. In addition to this, patients carry out different daily life activities, and might show lifestyle habits which are not entirely adequate to manage migraine day by day. Education will be more and more important as a strategy of brain health promotion, because this will enable reducing the amount of subjects needing specialty care, thus leaving it to those who require it in reason of refractory condition or presence of comorbidities.

CONCLUSIONS

Recognizing the hallmarks of migraine and the features of single patients enables prescribing specific pharmacological and non-pharmacological treatments. Medical research on headaches today particularly suffers from the syndrome of single-disease approach, but it is important to have a cross-sectional and joint vision with other close specialties, in order to treat our patients with a comprehensive approach that a heterogeneous condition like migraine requires.

Loss of Calcitonin Gene Related Receptor component protein (RCP) in nervous system can bias "gepant" antagonism

We examined calcitonin gene-related peptide (CGRP)'s effects on behavioral surrogates for motion-induced nausea and static imbalance in the nestinRCP (-/-), a novel mouse model that loses expression of receptor component protein (RCP) in the nervous system after tamoxifen induction. The assays used were the motion-induced thermoregulation and center of pressure (CoP) assays. Findings suggest CGRP's affects behavioral measures in the nestinRCP (-/-) similarly to littermate controls, since CGRP was observed to increase female sway and diminishes tail vasodilations to provocative motion in both sexes. However, the CGRP-receptor antagonist olcegepant did not antagonize CGRP's effects in the nestinRCP (-/-), whereas it was effective in littermate controls. Findings suggest RCP loss may change the sensitivity of the CGRP receptor and affect the efficacy of receptor antagonists.

Significance Statement

Research in calcitonin gene-related peptide (CGRP) has primarily focused on ligand- receptor interactions at the calcitonin-like receptor (CLR) and receptor activity-modifying unit 1 (RAMP1) subunits. However, the role of receptor component protein (RCP), which mediates signaling via the Gα-stimulatory pathway, is less understood. A novel tamoxifen-inducible mouse model, nestinRCP (-/-), was generated to study loss of RCP in CGRP signaling in the nervous system, and behavioral changes to motion-induced nausea and postural sway were studied after systemic injections of CGRP or CGRP co-delivered with migraine drugs. Findings from this study suggest the loss of CGRP-RCP can bias "gepant" antagonists like olcegepant, and may promote development of therapies to inhibit the RCP-CLR interactions.

Differential expression of components of the CGRP-receptor family in human coronary and human middle meningeal arteries: functional implications

BACKGROUND

Different responses in human coronary arteries (HCA) and human middle meningeal arteries (HMMA) were observed for some of the novel CGRP receptor antagonists, the gepants, for inhibiting CGRP-induced relaxation. These differences could be explained by the presence of different receptor populations in the two vascular beds. Here, we aim to elucidate which receptors are involved in the relaxation to calcitonin gene-related peptide (CGRP), adrenomedullin (AM) and adrenomedullin 2 (AM2) in HCA and HMMA.

METHODS

RNA was isolated from homogenized human arteries (23 HCAs; 12 F, 11 M, age 50 ± 3 years and 26 HMMAs; 14 F, 12 M, age 51 ± 3 years) and qPCR was performed for different receptor subunits. Additionally, relaxation responses to CGRP, AM or AM2 of the human arteries were quantified using a Mulvany myograph system, in the presence or absence of the adrenomedullin 1 receptor antagonist AM22-52 and/or olcegepant.

RESULTS

Calcitonin-like receptor (CLR) mRNA was expressed equally in both vascular beds, while calcitonin receptor (CTR) and receptor activity-modifying protein 3 (RAMP3) expression was low and could not be detected in all samples. RAMP1 expression was similar in HCA and HMMA, while RAMP2 expression was higher in HMMA. Moreover, receptor component protein (RCP) expression was higher in HMMA than in HCA. Functional experiments showed that olcegepant inhibits relaxation to all three agonists in both vascular beds. In HCA, antagonist AM22-52 did not inhibit relaxation to any of the agonists, while a trend for blocking relaxation to AM and AM2 could be observed in HMMA.

CONCLUSION

Based on the combined results from receptor subunit mRNA expression and the functional responses in both vascular tissues, relaxation of HCA is mainly mediated via the canonical CGRP receptor (CLR-RAMP1), while relaxation of HMMA can be mediated via both the canonical CGRP receptor and the adrenomedullin 1 receptor (CLR-RAMP2). Future research should investigate whether RAMP2 predominance over RAMP1 in the meningeal vasculature results in altered migraine susceptibility or in a different response to anti-migraine medication in these patients. Moreover, the exact role of RCP in CGRP receptor signalling should be elucidated in future research.

Assessment of Bone Mineral Density Over 1 Year in a Cross-Sectional Cohort of Migraine Patients Receiving Anti-CGRP Monoclonal Antibodies

BACKGROUND

Calcitonin gene-related peptide (CGRP), implicated in migraine pain, also possesses bone anabolic properties, which leads to the possibility that monoclonal antibodies targeting CGRP (anti-CGRPs) might increase the risk of bone density abnormalities.

OBJECTIVE

The objective of this study was to explore bone mineral density abnormalities in a cohort of migraine patients treated with anti-CGRPs.

METHODS

This was a single-center, cross-sectional, cohort study including migraine patients who underwent a densitometry assessment during anti-CGRP treatment. We assessed the frequency of osteopenia or osteoporosis (OSTEO+ status), defined as a bone mineral density T-score of -1 to -2.5, and <-2.5 standard deviations from the young female adult mean, respectively. Additionally, the association of OSTEO+ status with anti-CGRP treatment duration and primary osteoporosis' risk factors was investigated using logistic regression models.

RESULTS

Data from 51 patients (43 female, mean age 46 ± 13.9 years) were evaluated. The mean duration of anti-CGRP treatment was 15.7 (±11.8) months. Twenty-seven patients (53%) were OSTEO+ (n = 22 osteopenia; n = 5 osteoporosis). In the final model, menopause [odds ratio 11.641 (95% confidence interval 1.486-91.197), p = 0.019] and anti-seizure drug use [odds ratio 12.825 (95% confidence interval 1.162-141.569), p = 0.037] were associated with OSTEO+ status.

CONCLUSIONS

In our cohort of migraine patients, no evidence of an association between anti-CGRP treatment duration and an increasing risk of bone mineral density abnormalities was found. However, these findings are preliminary and necessitate further longitudinal research with larger cohorts and extended follow-up to be validated.

Association between severe headache or migraine and lipid accumulation product and visceral adiposity index in adults: a cross-sectional study from NHANES

BACKGROUND

Existing literature on the impact of lipid accumulation product (LAP) and visceral adiposity index (VAI) on severe headache or migraine is limited. This study aims to elucidate the association between LAP and VAI and the prevalence of migraine.

METHODS

Data for this study were sourced from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). A database-self-administered questionnaire was used to assess severe headache or migraine. A weighted logistic regression model was employed to assess the relationship between LAP and VAI with migraine prevalence. Complementary analytical approaches included subgroup analysis, restricted cubic spline (RCS), and threshold effect analysis to validate the findings.

RESULTS

In the end, 4572 people were recruited for the research, including 880 with migraine and 3692 without migraine. Following adjustment for the relevant covariables, weighted logistic regression analysis (OR = 1.409, 95% CI: 1.054, 1.883, P = 0.022; OR = 1.288, 95% CI: 1.010, 1.642, P = 0.042) revealed significantly elevated odds of migraine prevalence in participants within the highest tertile (T3) of LAP and VAI than those in the lowest tertile (T1). The nonlinear association between migraine prevalence and both VAI and LAP was further elucidated through a restricted cubic spline. The threshold analysis pinpointed 2.142 (log-likelihood ratio = 0.016) as the critical inflection point for VAI. Subgroup analysis and interaction testing revealed the significant association was independent in different subgroup factors.

CONCLUSIONS

The data indicate a robust association between higher levels of LAP and VAI and an increased prevalence of migraine.

Comparison of gepant effects at therapeutic plasma concentrations: connecting pharmacodynamics and pharmacokinetics

BACKGROUND

Orally administered second-generation gepants are effective for the treatment of migraine. The intranasal administration of the third-generation gepant zavegepant might have additional benefits including a rapid onset of action, but it is not clear yet to which extent this has clinical relevance.

METHODS

We examined the effect of zavegepant on the relaxations induced by calcitonin gene-related peptide (CGRP) in human isolated middle meningeal arteries. Furthermore, we connected the pharmacodynamics and pharmacokinetics of gepants by combining data from clinical and basic research.

RESULTS

We showed that 10 nM zavegepant potently antagonized the functional response to CGRP. We also showed that all gepants are effective at inhibiting functional responses to CGRP at their therapeutic plasma concentrations.

CONCLUSIONS

The relatively low predicted potency of zavegepant to inhibit CGRP-induced relaxation at therapeutic systemic plasma concentrations may point to the relevance of local delivery to the trigeminovascular system through intranasal administration. This approach may have additional benefits for various groups of patients, including overweight patients.

Drug effects on neuropeptides and their receptors: Big hopes but moderate success in the treatment of chronic pain

Neuropeptides, including tachykinins, CGRP, and somatostatin, are localized in a peptidergic subgroup of nociceptive primary afferent neurons. Tachykinins and CGRP are pronociceptive, somatostatin is an antinociceptive mediator. Intensive drug research has been performed to develop tachykinin and CGRP antagonists, and somatostatin agonists as analgesics. CGRP receptor antagonists are efficacious and well-tolerated drugs in migraine. Monoclonal antibodies against CGRP or its receptor are used for the prophylactic treatment of migraine. Tachykinin NK1 receptor antagonists failed as analgesics but are used for chemotherapy-induced nausea and vomiting. New, orally active somatostatin 4 receptor agonists are promising drug candidates for treating various pain conditions.

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.

An update on pharmacotherapy for trigeminal neuralgia

INTRODUCTION

Trigeminal neuralgia is a rare condition that can be effectively treated by carbamazepine or oxcarbazepine but these older drugs are associated with dose-dependent and potentially treatment-limiting adverse effects. Third-generation anticonvulsants, new calcitonin gene-related peptide blockers for migraine, and older drugs such as ketamine and cannabinoids may be promising adjuvants or monotherapeutic options.

AREAS COVERED

The new drugs, their presumed mechanisms of action, safety and efficacy are discussed herein. There is a paucity of robust clinical evidence in support of these drugs for trigeminal neuralgia. New migraine agents are considered as well although migraines and trigeminal neuralgia are distinct, albeit similar, conditions. No new drugs have been released to market in recent years with the specific indication of trigeminal neuralgia.

EXPERT OPINION

In real-world clinical practice, about half of trigeminal neuralgia patients take more than one agent for prevention and combination therapy may be the optimal approach. Combination therapy might allow for lower doses of carbamazepine or oxcarbazepine, thus reducing the number and severity of potential adverse events but the potential for pharmacokinetic drug-drug interactions must be considered. Drug therapy for trigeminal neuralgia involves acute or abortive treatments, often administered in hospital versus long-term preventive therapy, usually involving oral agents.

Molecular nociceptive mechanisms in migraine: The migraine cascade

OBJECTIVE

This review will explore the categorization of migraine-provoking molecules, their cellular actions, site of action and potential drug targets based on the migraine cascade model.

METHODS

Personal experience and literature.

RESULTS

Migraine impacts over 1 billion people worldwide but is underfunded in research. Recent progress, particularly through the human and animal provocation model, has deepened our understanding of its mechanisms. This model have identified endogenous neuropeptides such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating peptide (PACAP) that induces controlled migraine-like attacks leading to significant discoveries of their role in migraine. This knowledge led to the development of CGRP-inhibiting drugs; a groundbreaking migraine treatment now accessible globally. Also a PACAP-inhibiting drug was effective in a recent phase II trial. Notably, rodent studies have shed light on pain pathways and the mechanisms of various migraine-inducing substances identifying novel drug targets. This is primarily done by using selective inhibitors that target specific signaling pathways of the known migraine triggers leading to the hypothesized cellular cascade model of migraine.

CONCLUSION

The model of migraine presents numerous opportunities for innovative drug development. The future of new migraine treatments is limited only by the investment from pharmaceutical companies.

VPAC1 and VPAC2 receptors mediate tactile hindpaw hypersensitivity and carotid artery dilatation induced by PACAP38 in a migraine relevant mouse model

BACKGROUND

Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide pivotal in migraine pathophysiology and is considered a promising new migraine drug target. Although intravenous PACAP triggers migraine attacks and a recent phase II trial with a PACAP-inhibiting antibody showed efficacy in migraine prevention, targeting the PACAP receptor PAC1 alone has been unsuccessful. The present study investigated the role of three PACAP receptors (PAC1, VPAC1 and VPAC2) in inducing migraine-relevant hypersensitivity in mice.

METHODS

Hindpaw hypersensitivity was induced by repeated PACAP38 injections. Tactile sensitivity responses were quantified using von Frey filaments in three knockout (KO) mouse strains, each lacking one of the PACAP-receptors (Ntotal = 160). Additionally, ex vivo wire myography was used to assess vasoactivity of the carotid artery, and gene expression of PACAP receptors was examined by qPCR.

RESULTS

PACAP38 induced hypersensitivity in WT controls (p < 0.01) that was diminished in VPAC1 and VPAC2 KO mice (p < 0.05). In contrast, PAC1 KO mice showed similar responses to WT controls (p > 0.05). Myograph experiments supported these findings showing diminished vasoactivity in VPAC1 and VPAC2 KO mice. We found no upregulation of the non-modified PACAP receptors in KO mice.

CONCLUSIONS

This study assessed all three PACAP receptors in a migraine mouse model and suggests a significant role of VPAC receptors in migraine pathophysiology. The lack of hypersensitivity reduction in PAC1 KO mice suggests the involvement of other PACAP receptors or compensatory mechanisms. The results indicate that targeting only individual PACAP receptors may not be an effective migraine treatment.

Migraine inhibitor olcegepant reduces weight loss and IL-6 release in SARS-CoV-2-infected older mice with neurological signs

COVID-19 can cause neurological symptoms such as fever, dizziness, and nausea. However, such neurological symptoms of SARS-CoV-2 infection have been hardly assessed in mouse models. In this study, we infected two commonly used wild-type mouse lines (C57BL/6J and 129/SvEv) and a 129S calcitonin gene-related peptide (αCGRP) null-line with mouse-adapted SARS-CoV-2 and demonstrated neurological signs including fever, dizziness, and nausea. We then evaluated whether a CGRP receptor antagonist, olcegepant, a "gepant" antagonist used in migraine treatment, could mitigate acute neuroinflammatory and neurological signs of SARS-COV-2 infection. First, we determined whether CGRP receptor antagonism provided protection from permanent weight loss in older (>18 m) C57BL/6J and 129/SvEv mice. We also observed acute fever, dizziness, and nausea in all older mice, regardless of treatment. In both wild-type mouse lines, CGRP antagonism reduced acute interleukin 6 (IL-6) levels with virtually no IL-6 release in mice lacking αCGRP. These findings suggest that migraine inhibitors such as those blocking CGRP receptor signaling protect against acute IL-6 release and subsequent inflammatory events after SARS-CoV-2 infection, which may have repercussions for related pandemic or endemic coronavirus outbreaks.IMPORTANCECoronavirus disease (COVID-19) can cause neurological symptoms such as fever, headache, dizziness, and nausea. However, such neurological symptoms of severe acute respiratory syndrome CoV-2 (SARS-CoV-2) infection have been hardly assessed in mouse models. In this study, we first infected two commonly used wild-type mouse lines (C57BL/6J and 129S) with mouse-adapted SARS-CoV-2 and demonstrated neurological symptoms including fever and nausea. Furthermore, we showed that the migraine treatment drug olcegepant could reduce long-term weight loss and IL-6 release associated with SARS-CoV-2 infection. These findings suggest that a migraine blocker can be protective for at least some acute SARS-CoV-2 infection signs and raise the possibility that it may also impact long-term outcomes.

Trigeminal ganglion neurons are directly activated by influx of CSF solutes in a migraine model

Classical migraine patients experience aura, which is transient neurological deficits associated with cortical spreading depression (CSD), preceding headache attacks. It is not currently understood how a pathological event in cortex can affect peripheral sensory neurons. In this study, we show that cerebrospinal fluid (CSF) flows into the trigeminal ganglion, establishing nonsynaptic signaling between brain and trigeminal cells. After CSD, ~11% of the CSF proteome is altered, with up-regulation of proteins that directly activate receptors in the trigeminal ganglion. CSF collected from animals exposed to CSD activates trigeminal neurons in naïve mice in part by CSF-borne calcitonin gene-related peptide (CGRP). We identify a communication pathway between the central and peripheral nervous system that might explain the relationship between migrainous aura and headache.

The preclinical discovery and development of atogepant for migraine prophylaxis

INTRODUCTION

Atogepant is a selective calcitonin gene-related peptide (CGRP) receptor antagonist that is utilized in adults for the prevention of episodic and chronic migraine. Cumulative findings support the involvement of CGRP in migraine pathophysiology, and atogepant functions by competitively antagonizing CGRP receptors, which results in the inhibition of trigeminovascular nociception. The mechanism of action addresses the cause of migraine pain, providing an effective preventive treatment option.

AREAS COVERED

The key milestones in its development, including preclinical achievements, phase I, II, and III clinical trials, and regulatory approvals are reviewed. Additionally, clinical efficacy, safety profile, and tolerability of atogepant are discussed. The literature review is based on a comprehensive search of English peer-reviewed articles from various electronic databases, including PubMed and ClinicalTrials.gov.

EXPERT OPINION

The development of atogepant represents a significant breakthrough in migraine prevention, particularly due to its improved safety profile that reduces the risk of liver injury, which was a major limitation of first-generation gepants. Drug-drug interaction studies with atogepant highlight the necessity for more inclusive study populations. Given that migraine disproportionately affects females, future clinical development programs should include diverse patient demographics to ensure the findings are generalizable to all individuals suffering from migraine.

Provocation of attacks to discover migraine signaling mechanisms and new drug targets: early history and future perspectives - a narrative review

INTRODUCTION

The development of several experimental migraine provocation models has significantly contributed to an understanding of the signaling mechanisms of migraine. The early history of this development and a view to the future are presented as viewed by the inventor of the models.

METHODS

Extensive knowledge of the literature was supplemented by scrutiny of reference lists.

RESULTS

Early studies used methodologies that were not blinded. They suggested that histamine and nitroglycerin (Glyceryl trinitrate, GTN) could induce headache and perhaps migraine. The development of a double blind, placebo-controlled model, and the use of explicit diagnostic criteria for induced migraine was a major step forward. GTN, donor of nitric oxide (NO), induced headache in people with- and without migraine as well as delayed migraine attacks in those with migraine. Calcitonin gene-related peptide (CGRP) did the same, supporting the development of CGRP antagonists now widely used in patients. Likewise, pituitary adenylate cyclase activating peptide (PACAP) provoked headache and migraine. Recently a PACAP antibody has shown anti migraine activity in a phase 2 trial. Increase of second messengers activated by NO, CGRP and PACAP effectively induced migraine. The experimental models have also been used in other types of headaches and have been combined with imaging and biochemical studies. They have also been used for drug testing and in genetic studies.

CONCLUSION

Conclusion. Human migraine provocation models have informed about signaling mechanisms of migraine leading to new drugs and drug targets. Future use of these models in imaging-, biochemistry- and genetic studies as well as in the further study of animal models is promising.

Efficacy of Lasmiditan as a Secondary Treatment for Migraine Attacks after Unsuccessful Treatment with a Triptan

The combined use of lasmiditan and triptan is unexplored in medical literature. This study aimed to investigate whether the intake of lasmiditan following triptan improves migraine pain. Following triptan intake, if headache relief was less than 50% at 1 h, patients took 50 mg of lasmiditan within 2 h of migraine onset. Patients recorded headache intensity and adverse events (AEs) caused by lasmiditan at 1, 2, and 4 h after the intake of an additional 50 mg of lasmiditan. A significant reduction in pain scale was observed post 50 mg lasmiditan intake (p < 0.001, t-test). Pain relief was reported for 32 migraine attacks (80%) at 1 h after additional lasmiditan intake. Although AEs were observed in 63% of the patients who took an additional lasmiditan, most were mild and resolved 1 h after lasmiditan intake. Our study revealed the significant headache relief provided by an additional lasmiditan for patients who did not achieve satisfactory results following initial triptan intake for treating migraine. The AEs associated with this treatment strategy were mild and lasted for a short time. This study suggested that the combination of triptan and lasmiditan is promising for the treatment of migraine and should be studied in a randomized placebo-controlled trial.

Altered immunity in migraine: a comprehensive scoping review

BACKGROUND

The pathogenesis of migraine remains unclear; however, a large body of evidence supports the hypothesis that immunological mechanisms play a key role. Therefore, we aimed to review current studies on altered immunity in individuals with migraine during and outside attacks.

METHODS

We searched the PubMed database to investigate immunological changes in patients with migraine. We then added other relevant articles on altered immunity in migraine to our search.

RESULTS

Database screening identified 1,102 articles, of which 41 were selected. We added another 104 relevant articles. We found studies reporting elevated interictal levels of some proinflammatory cytokines, including IL-6 and TNF-α. Anti-inflammatory cytokines showed various findings, such as increased TGF-β and decreased IL-10. Other changes in humoral immunity included increased levels of chemokines, adhesion molecules, and matrix metalloproteinases; activation of the complement system; and increased IgM and IgA. Changes in cellular immunity included an increase in T helper cells, decreased cytotoxic T cells, decreased regulatory T cells, and an increase in a subset of natural killer cells. A significant comorbidity of autoimmune and allergic diseases with migraine was observed.

CONCLUSIONS

Our review summarizes the findings regarding altered humoral and cellular immunological findings in human migraine. We highlight the possible involvement of immunological mechanisms in the pathogenesis of migraine. However, further studies are needed to expand our knowledge of the exact role of immunological mechanisms in migraine pathogenesis.