The trigeminovascular system and migraine: studies characterizing cerebrovascular and neuropeptide changes seen in humans and cats

Safety and tolerability of ubrogepant for the acute treatment of migraine in participants taking atogepant for the preventive treatment of episodic migraine: Results from the TANDEM study

OBJECTIVE

To evaluate the safety and tolerability of ubrogepant for the acute treatment of migraine in participants taking atogepant for the preventive treatment of episodic migraine (EM).

BACKGROUND

Atogepant is an oral calcitonin gene-related peptide (CGRP) receptor antagonist approved for the preventive treatment of migraine in adults and ubrogepant is an oral CGRP receptor antagonist approved for the acute treatment of migraine in adults, with or without aura. The safety and tolerability of the concomitant use of ubrogepant and atogepant have not been previously evaluated in a clinical setting.

METHODS

The TANDEM study, a phase 4, two-period, multicenter, open-label study conducted in the United States, enrolled adults with migraine, with or without aura, and <15 headache days/month. In Treatment Period 1, participants took atogepant 60 mg once daily (QD) for 12 weeks and their own non-gepant acute headache medication for breakthrough migraine attacks. In Treatment Period 2, participants continued taking atogepant 60 mg QD and ubrogepant 100 mg was taken as needed (PRN) for the treatment of breakthrough migraine attacks (up to eight per 4-week interval) for 12 weeks. In Treatment Period 2, an optional second ubrogepant dose or the participant's own acute medication could be used to rescue headaches that did not resolve within 2-24 h post initial ubrogepant dose. The primary objective evaluated the safety and tolerability of the concomitant use of ubrogepant and atogepant.

RESULTS

Of 263 participants enrolled, 262 were treated in Treatment Period 1 (Safety Population 1) and 218 continued and were treated in Treatment Period 2 (Safety Population 2). The mean (standard deviation) number of ubrogepant use days in Treatment Period 2 was 6.6 (5.03) over the 12 weeks. In Treatment Periods 1 and 2, 49.6% and 43.1% of participants experienced a treatment-emergent adverse event (TEAE), respectively. The most common TEAEs (≥5%) in Treatment Period 1 and Treatment Period 2 were COVID-19 (8.4%, 3.2%), fatigue (6.5%, 1.4%), nausea (6.1%, 0.9%), decreased appetite (5.7%, 0.9%), and constipation (5.3%, 0.9%). In Treatment Period 2, no increase in the incidence and types of TEAEs in relation to the number of ubrogepant use days or doses taken were identified. During the whole treatment period, 9.9% of participants discontinued atogepant or ubrogepant treatment due to TEAEs. There was one serious TEAE in Treatment Period 1 (ureterolithiasis) and one in Treatment Period 2 (cervical myelopathy), and both were considered not related to study treatment by the study investigators.

CONCLUSION

The use of atogepant 60 mg QD for the preventive treatment of EM and ubrogepant 100 mg PRN for the acute treatment of migraine over the 12-week open-label concomitant use treatment period was safe and well tolerated. The overall safety results were consistent with the known safety profiles of atogepant and ubrogepant when used alone and no new safety signals were identified.

Substance P release from rat dura mater is inversely correlated with CGRP release- experiments using glycerol trinitrate and anti-CGRP antibodies

BACKGROUND

The neuropeptides calcitonin gene-related peptide (CGRP) and substance P are important mediators of neurogenic inflammation when they are released from activated primary nociceptive afferents. It is long evident that neuropeptides play an important role in migraine pathophysiology, but the significance of neurogenic inflammation is still debated.

METHODS

In an approved hemisected rodent head preparation, we measured CGRP release from the cranial dura mater in parallel with substance P release using animals pre-treated with anti-CGRP antibodies or control solutions.

RESULTS

Apart from the known decrease in CGRP release following antibody treatment, we found a significant inverse correlation of basal and stimulated CGRP versus substance P release across all experiments. The results are discussed in connection with our previously published data.

CONCLUSIONS

An increase in CGRP release seems to inhibit substance P release in meningeal structures possibly decreasing substance P-dependent plasma extravasation, which argues against a significant role of neurogenic inflammation in migraine.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

The role and interaction of hypothalamic-related neurotransmitters in migraine

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

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

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

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.

Assessing Blood Pressure Effects of Anti-CGRP Antibody Treatment in Migraine: A Retrospective Real-World Analysis

Background: Anti-CGRP (receptor) antibodies are approved for the preventive treatment of migraines and are increasingly used due to their favorable safety profile and potent efficacy. However, as CGRP is one of the most potent vasodilators, concerns have been raised regarding the possible impact of these drugs on arterial blood pressure. Methods: We present a retrospective cohort study at a tertiary headache center including a total of 259 patients with episodic and chronic migraine who received anti-CGRP antibody treatment for migraine prevention. Blood pressure was measured in a hospital using a standardized setting at baseline and at least at two follow-up visits. Significant increase in blood pressure was defined as an increase in systolic blood pressure ≥ 20 mmHg and/or an increase in diastolic blood pressure ≥ 10 mmHg from the baseline value. Results: Mean age of our population was 39.9 years (±12.1), and 217 (83.8%) were female. Blood pressure measurements between T0 and T2, incorporating all CGRP-antibody groups, showed a significant reduction in systolic (-3.3 mmHg; p = 0.001) and diastolic blood pressure (-2.3 mmHg; p = 0.021), respectively. The repeated-measures generalized linear model analysis revealed no significant variations between the CGRP antibodies relative to blood pressure. The most robust factor predicting systolic hypertensive measurements in the course of anti-CGRP antibody treatment was pre-existing hypertension at baseline (sum of mean squares 7.4; p = 0.019). Conclusions: Our data indicate that treatment with anti-CGRP (receptor) antibodies does not significantly increase blood pressure. However, it seems to be important to monitor patients with pre-existing arterial hypertension.

Unraveling the relationship between inflammation and cluster headache

Cluster headache (CH) is often referred to as the 'suicide headache.' Existing research suggests that the activation of the trigeminal-vascular system, increased sensitivity of nerve fibers, and the release and interaction of various neuropeptides and inflammatory mediators may contribute to neurogenic inflammation, which serves as a crucial pathophysiological basis for the development of CH. Additionally, some neuropeptides can modulate neuronal activity related to pain transmission and may increase pain perception by sensitizing central nerves. This review discusses the neuropeptides and inflammatory mediators associated with CH neuroinflammation, focusing on calcitonin gene-related peptide (CGRP), inflammatory cytokines and related signaling pathways, nitric oxide (NO), pituitary adenylate cyclase-activating peptide 38 (PACAP-38), and vasoactive intestinal peptide (VIP), incorporating both preclinical and clinical evidence to provide new insights into potential therapeutic targets for CH.

Diffuse cerebral vasodilatation at the initial stage of reversible cerebral vasoconstriction syndrome (RCVS)

BACKGROUND AND PURPOSE

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by recurrent thunderclap headaches and segmental vasoconstriction of cerebral arteries resolutive within three months. However, two case reports in the literature revealed diffuse cerebral vasodilatation rather than vasoconstriction at the early phase of RCVS (Kobayashi, 2016; Oikawa et al., 2017). This study aims at reporting the occurrence of diffuse cerebral vasodilatation at the initial stage of RCVS and at analyzing the clinical and prognostic characteristics of patients with diffuse vasodilatation.

MATERIALS AND METHODS

Patients with RCVS were retrospectively gathered from medical files. Initial and follow-up vascular imaging were compared to assess vasodilatation and vasoconstriction for each segment of the circle of Willis on the initial angiogram. Diffuse vasodilatation was defined as dilatation of four or more of the circle of Willis arteries both in the anterior and posterior circulations, without previously described "string of beads" appearance of cerebral arteries. Patients were split into two groups based on the presence of diffuse cerebrovascular dilatation for comparison.

RESULTS

Among 148 patients with RCVS, 45 patients (30%) had diffuse cerebral vasodilatation. Diffuse vasodilatation was proved to occur at the early phase of RCVS (mean delay between thunderclap headache onset and initial imaging of 2.25days versus 7.63days, P=0.047) and mainly affected the first and second segments of major cerebral arteries. It was significatively associated with distal vasoconstriction (44.44% versus 25.24%, P=0.033). Patients with diffuse cerebral vasodilatation had a greater risk of hemorrhage (15.56% for subarachnoid hemorrhage versus 3.88%, P=0.035; 8.89% for intracranial hemorrhage versus 0.97%, P=0.03). Vasodilatation was more frequent in women (71.11% versus 41.75%, P=0.001). Secondary forms of RCVS were associated with diffuse vasodilatation (51% versus 27%, P=0.008).

CONCLUSION

The early cerebral angiogram may reveal diffuse cerebrovascular dilatation in patients with RCVS. Vasodilatation might have a pathophysiological implication in RCVS with clinical and prognostic consequences for patients.

Activation of δ-opioid receptors blocks allodynia in a model of headache induced by PACAP

BACKGROUND AND PURPOSE

Pituitary adenylate cyclase activating polypeptide (PACAP) is a human migraine trigger that is being targeted for migraine. The δ-opioid receptor (δ-receptor) is a novel target for the treatment of migraine, but its mechanism remains unclear. The goals of this study were to develop a mouse PACAP-headache model using clinically significant doses of PACAP; determine the effects of δ-receptor activation in this model; and investigate the co-expression of δ-receptors, PACAP and PACAP-PAC1 receptor.

EXPERIMENTAL APPROACH

Cephalic allodynia to low doses of acute and chronic PACAP were tested. A triptan (sumatriptan) and a CGRP receptor antagonist (olcegepant) were tested in this model. The δ-receptor agonist SNC80 was tested in PACAP and CGRP-induced headache models. Expression of PACAP, PAC1, CRLR and δ-receptors was determined using in situ hybridisation.

KEY RESULTS

Low doses of PACAP produced dose-dependent acute and chronic cephalic allodynia, blocked by sumatriptan but not by olcegepant. The PAC1 antagonist (M65) did not inhibit CGRP-induced allodynia. There was moderate co-expression of PAC1 and CRLR transcripts in migraine-related regions. SNC80 blocked PACAP- and CGRP-induced allodynia. There was low co-expression of PACAP and δ-receptors in brain regions measured. However, there was high co-expression of PAC1 and δ-receptors in somatosensory cortex, hippocampus and trigeminal nucleus caudalis.

CONCLUSION AND IMPLICATIONS

We developed a translationally significant model of PACAP-induced headache, which was mechanistically distinct from CGRP. Activation of δ-receptors blocked PACAP- and CGRP-induced allodynia, and δ-receptors were highly co-expressed with the PACAP-ergic system. Future studies will examine the functional relationship between δ-receptors and PAC1.

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.

The Role of Purinergic Mechanisms in the Excitability of Trigeminal Afferents of Rats with Prenatal Hyperhomocysteinemia

Elevated levels of homocysteine in the blood plasma (hyperhomocysteinemia, HHCY) positively correlate with migraine symptoms in patients. Experimental studies show a higher sensitivity of rats with prenatal HHCY (pHHCY) to migraine symptoms like allodynia, photophobia, anxiety, and a higher excitability of meningeal trigeminal afferents. In the present study, the roles of purinergic mechanisms in the homocysteine-induced hyperexcitability of the trigeminal ganglion (TG) system using electrophysiological recordings from the trigeminal nerve, Ca2+ imaging of cells isolated from TG, and mast cell staining in meninges were investigated. Experiments were performed using rats with pHHCY born from females fed with a high-methionine-containing diet before and during pregnancy. Firstly, we found that lower concentrations of 4-aminopyridine, a K+-channel blocker, were able to induce an increase in the nociceptive activity of trigeminal afferents, supporting the hypothesis of the higher excitability of the trigeminal nerve of rats with pHHCY. Trigeminal afferents of rats with pHHCY were more sensitive to the exogenous application of the nonspecific agonist of purinergic ATP receptors. In neurons and satellite glial cells of TG of rats with pHHCY ATP, ADP (an agonist of metabotropic P2Y receptors) and BzATP (an agonist of ionotropic P2X with especially high potency for the P2X7 receptor) induced larger Ca2+ transients. The incubation of TG neurons in homocysteine for 24 h increased the ratio of neurons responding simultaneously to ATP and capsaicin. Moreover, rats with pHHCY exhibit a higher rate of degranulation of mast cells and increased response to the agonist of the P2X7 receptor BzATP application. In addition, higher levels of calcitonin gene-related peptide (CGRP) were found in rats with pHHCY. Our results suggest that chronic elevated levels of homocysteine induce the upregulation of ionotropic or metabotropic ATP receptors in neurons, satellite glial cells, and mast cells, which further provide inflammatory conditions and the sensitization of peripheral afferents underlying pain.

One-step ultra-rapid immunoassay of calcitonin gene-related peptide for migraine diagnosis

Migraine is known to be caused by calcitonin gene-related peptide (CGRP), prompting the need for quantitative analysis of CGRP for the clinical treatment of monoclonal antibodies targeting CGRP. Since CGRP is cleaved by proteolytic enzymes post-blood collection, rapid analysis methods are required. In this study, a one-step immunoassay for CGRP was developed using chemically mimicking peptides (mimotopes) with an analysis time of 32 min. Four clones from an Fv-antibody library were screened using two types of monoclonal antibodies against CGRP. Mimotopes for each monoclonal antibody were synthesized into peptides of 15 residues. The binding affinity (KD) was estimated, and the interaction with monoclonal antibodies was analyzed using docking simulations. Finally, a one-step immunoassay for CGRP was demonstrated using migraine patient samples (n = 57) and healthy volunteer controls (n = 18). The limit of detection (LOD) of one-step immunoassay based on Fremanezumab (mimotope F1) was estimated to be 8.8 pg/mL with the limit of quantification (LOQ) of 125.9 pg/mL. And, the one-step immunoassay based on Galcanezumab (mimotope G7) showed the LOD of 9.4 pg/mL and the LOQ of 84.7 pg/mL. The total analysis time was estimated to be approximately 32 min and the assay results were estimated to be statistically consistent with conventional CGRP assay.

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.

The Role of Calcitonin Gene-Related Peptide and Amylin in Pediatric Migraine

BACKGROUND

Very few studies have examined the relationship between calcitonin gene-related peptide (CGRP) and amylin levels and the disease in patients with migraine. The purpose of this study was to compare blood CGRP and amylin levels between pediatric migraine patients and healthy controls and the relationship between CGRP and amylin levels and migraine attack frequency and duration.

MATERIALS AND METHODS

The study involved two separate groups-control and migraine. Thirty-two patients aged 6 to 18 years presenting to the Balikesir University Medical Faculty pediatric neurology clinic and diagnosed with migraine were included. The control group consisted of 32 patients without migraine presenting to the clinic during the same time frame. The patients' demographic data, personal and family histories, migraine type and frequency, headache severity, basic anthropometric measurements (height, weight, and body mass index), and physical and neurological examination findings were recorded. Migraine patients were classified as ictal if the collection of blood specimens coincided with the attack period and as interictal if this was performed between attacks.

RESULTS

No statistically significant differences in mean CGRP or amylin levels were determined between the groups (migraine ictal/interictal) or between the migraine patients (in terms of gender or attack frequency and duration).

CONCLUSION

Elucidating the complex processes involved in the pathogenesis of migraine is important in terms of our ability to develop new treatments and therapeutic strategies. This study aimed to evaluate CGRP and amylin levels in patients with pediatric migraine (in the ictal and interictal periods) compared with those in healthy controls.

Current and Novel Therapies for Cluster Headache: A Narrative Review

Cluster headache (CH) is an excruciating and debilitating primary headache disorder. The prevalence is up to 1.3%, and the typical onset is around age 30. Often misdiagnosed as migraine, particularly in children, the diagnosis rate of CH has been increasing among women. CH is characterized by intense unilateral pain and autonomic symptoms, significantly impacting patients' quality of life, mental health, and productivity.Genetic associations suggest a familial risk for developing CH, with lifestyle factors also potentially playing a role. The pathophysiology involves alterations in both central and peripheral nervous system, with the hypothalamus, trigeminocervical complex, and neuropeptides such as calcitonin gene-related peptide (CGRP) being implicated.Nonpharmacological treatments focus on patient education and lifestyle modifications, while pharmacological treatments include acute therapies such as oxygen and subcutaneous or nasal sumatriptan, as well as preventive therapies like verapamil, lithium, and CGRP monoclonal antibodies. Transitional options include oral corticosteroids and greater occipital nerve injections. Emerging interventional procedures offer new avenues for managing refractory cases. Noninvasive vagal nerve stimulation and occipital nerve stimulation show promise for both acute and preventive treatment. Careful consideration of safety profiles is crucial in specific populations such as pregnant patients and children.Current treatments still leave patients highly burdened by limited efficacy and side effects. Future research continues to explore novel pharmacological targets, interventional procedures, and the potential role of psychedelics in CH management. Comprehensive, multifaceted treatment strategies are essential to improve the daily functioning and quality of life for individuals with CH.

Pipeline for development of acylated peptide based CGRP receptor antagonist with extended half-life for migraine treatment

Migraine is a debilitating headache disorder. The disease has neurovascular origin and migraine attacks can be elicited by vasodilative neuropeptides such as alpha calcitonin gene-related peptide (αCGRP). Antagonizing CGRP actions in migraine patients has proven clinically efficient. Here, we present a pipeline for development of a peptide-based hCGRP receptor antagonist with increased half-life capable of antagonising the vasodilatory effect of hαCGRP. A series of hαCGRP8-37 analogues carrying a C18-or C20-diacid lipidation was screened for their antagonism against the hCGRP receptor. hαCGRP8-37 analogues with a C20-diacid were 2-6 fold more potent than analogues conjugated with a C18-diacid. Half-life of hαCGRP8-37 analogues carrying a C20-diacid was estimated in mice in a pilot study (n = 1-2). Half-lives ranged from 7.3 to 13.7 h. An hαCGRP8-37 analogue conjugated with a C20 diacid at position 25 was subjected to an amino acid substitution scan to identify mutations that could further enhance hCGRP receptor antagonism. Substituting alanine with serine at position 36 resulted in a ~ 4 fold gain of potency. Vasodilative actions of hαCGRP were successfully antagonized by hαCGRP8-37 analogues carrying a C20 diacid at position 25. Our findings demonstrate that lipidation can improve hαCGRP8-37 pharmacokinetics while maintaining hαCGRP antagonism, thus demonstrating potential for a peptide-based migraine treatment strategy.

Population pharmacokinetic modeling of zavegepant, a calcitonin gene-related peptide receptor antagonist, in healthy adults and patients with migraine

Zavegepant (ZAVZPRET™) is a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist available for acute treatment of migraine in adults. A population pharmacokinetic analysis was performed to describe zavegepant plasma concentration-time course, characterize bioavailability, and identify covariates affecting zavegepant exposure. The model was developed and validated using data from 10 phase I clinical studies, wherein zavegepant was administered intravenously, intranasally, or orally to healthy adults and patients with migraine. Plasma concentration-time data were analyzed using nonlinear mixed-effects modeling. A three-compartment model with first-order elimination from the central compartment, and sequential zero- and first-order absorption best described the observed plasma concentration-time course of zavegepant. Bioavailability was 5.1% and 0.65% for intranasal and oral treatment, respectively; absorption rate constants were 5.8 and 0.8 h-1, respectively. Body weight-based empirical allometric scaling was applied using standard exponents (0.75 for clearance and 1 for volume of distribution). Age (range 18-71 years), race, ethnicity, sex, renal function, and co-administration of oral contraceptives or sumatriptan did not significantly change zavegepant pharmacokinetics. Moderate hepatic impairment (Child-Pugh score 7-9) or co-administration of rifampin decreased elimination clearance of oral zavegepant by ~40%. The zavegepant population pharmacokinetic model adequately characterized zavegepant concentration-time profiles, the bioavailability of intranasal and oral zavegepant, as well as the effect of intrinsic and extrinsic factors on zavegepant pharmacokinetics.

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.

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

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

Rimegepant for the acute and preventive treatment of migraine: a narrative review of the evidence

INTRODUCTION

Rimegepant is an oral small-molecule calcitonin gene-related peptide receptor antagonist approved in several countries for acute treatment of migraine and preventive treatment of episodic migraine in adults. This review summarizes the evidence, published to date, for the use of rimegepant as an acute or preventive treatment of migraine.

AREAS COVERED

A brief overview of migraine, the pharmacokinetics of rimegepant, and the mechanism of action of rimegepant are provided. Evidence evaluating rimegepant as an acute or preventive treatment of migraine is then summarized in more detail, based on a literature search for full-length publications related to clinical or real-world use of rimegepant.

EXPERT OPINION

Several clinical trials established rimegepant as a safe and effective treatment (acute and preventive) of migraine in adults. There are few head-to-head studies with other migraine treatments to determine relative efficacy. However, the favorable safety profile of rimegepant makes it appropriate for many patients, particularly those with contraindication, intolerance, or inadequate response to other classes of standard-of-care migraine treatments. Additional studies on the efficacy and cost-effectiveness relative to other treatments may further define the role of rimegepant in migraine treatment.

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.

Meningeal brain borders and migraine headache genesis

Migraine is a highly prevalent and disabling pain disorder that affects >1 billion people worldwide. One central hypothesis points to the cranial meninges as a key site underlying migraine headache genesis through complex interplay between meningeal sensory nerves, blood vessels, and adjacent immune cells. How these interactions might generate migraine headaches remains incompletely understood and a subject of much debate. In this review we discuss clinical and preclinical evidence supporting the concept that meningeal sterile inflammation, involving neurovascular and neuroimmune interactions, underlies migraine headache genesis. We examine downstream signaling pathways implicated in the development of migraine pain in response to exogenous events such as infusing migraine-triggering chemical substances. We further discuss cortex-to-meninges signaling pathways that could underlie migraine pain in response to endogenous events, such as cortical spreading depolarization (CSD), and explore future directions for the field.

Regional distribution of unbound eletriptan and sumatriptan in the CNS and PNS in rats: implications for a potential central action

BACKGROUND

Triptans are potent 5-HT1B/1D/1F receptor agonists used in migraine therapy, thought to act through peripheral mechanisms. It remains unclear whether triptans cross the blood-brain barrier (BBB) sufficiently to stimulate central 5-HT1B/1D/1F receptors. This study investigates the disposition of eletriptan and sumatriptan in central nervous system (CNS) and peripheral nervous system (PNS) regions and predicts regional 5-HT1B/1D/1F receptor occupancies at clinically relevant concentrations.

METHODS

Using the Combinatory Mapping Approach (CMA) for regions of interest (ROI), we assessed the unbound tissue-to-plasma concentration ratio (Kp, uu, ROI) in rats at steady state across CNS (hypothalamus, brain stem, cerebellum, frontal cortex, parietal cortex, striatum, hippocampus, whole brain, and spinal cord) and PNS (trigeminal ganglion and sciatic nerve) regions. We used Kp, uu, ROI values to estimate unbound target-site concentrations and 5-HT1B/1D/1F receptor occupancies in humans.

RESULTS

We observed heterogenous triptan transport across CNS and PNS regions with the highest extent of unbound drug transport across the blood-nerve barrier in the trigeminal ganglion (Kp, uu, TG: eletriptan: 0.519, and sumatriptan: 0.923). Both drugs displayed restricted entry across the BBB (Kp, uu, whole brain: eletriptan: 0.058, and sumatriptan: 0.045) combined with high inter-regional variability. We estimated near-complete receptor occupancy in the trigeminal ganglion, while lower occupancies were observed in the whole brain, irrespective of the drug or receptor subtype. For instance, eletriptan was predicted to achieve 84% 5-HT1B receptor occupancy in the trigeminal ganglion and 37% in the whole brain at clinically relevant concentrations.

CONCLUSIONS

This study suggests that despite low BBB transport, both eletriptan and sumatriptan achieve unbound concentrations sufficient to stimulate 5-HT1B, 5-HT1D, and 5-HT1F receptors not only in the trigeminal ganglion, but also in the CNS. Further research is needed to determine whether central mechanisms contribute to triptan's antimigraine effect and/or side effects.

Effect of fasting-induced headache on calcitonin gene related peptide (CGRP) and other clinical biomarkers on the first day of Ramadan: Sub-analysis from a randomized open label clinical trial

BACKGROUND

Fasting-induced headaches (FIHs) have been shown to occur on the first day of Ramadan and clearly decline thereafter. Despite the wealth of knowledge about different types of headaches (e.g., migraine-, cluster-, and tension-type headaches), research on the mechanism underlying FIHs, as well as their treatment, remains scarce. Our study aimed to investigate any association between FIHs during the first day of Ramadan and potential headache-related biomarkers, including fasting blood glucose (FBG), C-reactive protein (CRP), magnesium, vitamin B9, vitamin B12, homocysteine, and calcitonin gene related peptide (CGRP), and to assess whether a prophylactic use of paracetamol may influence these biomarkers.

METHODS

As part of a randomized, open-label clinical trial that evaluated the effect of paracetamol as a prophylactic therapy for FIH, blood samples from stratified subjects in the prophylaxis and control groups were withdrawn while fasting after the 1st dose of paracetamol (in the prophylaxis group) and prior to reporting headache occurrence.

RESULTS

Plasma and serum were separated for 61 subjects; 31 and 30 subjects from the prophylaxis and control groups, respectively. Overall, no significant differences were found in the levels of FBG, CRP, magnesium, vitamin B9, and vitamin B12 in headache-suffering subjects compared to those without headache despite the use of paracetamol for prophylaxis. Homocysteine, however, was significantly reduced in all subjects who experienced FIH compared to those without headache (median 6.9 [1.6] vs. 7.7 [2.7] umol/L; p = 0.041). On the contrary, when the CGRP was measured using immunoassay, it was found to be significantly elevated in all headache-suffering subjects compared to those without headache (median 126.1 [17.7] vs. 105.8 [19.6] pg/mL; p ≤ 0.0001). This difference was maintained upon comparing the headache to non-headache subjects in both the prophylaxis (median 121.5 [15.4] vs. 105.8 [9.4] pg/mL; p < 0.01) and control groups (median 128.5 [28.3] vs. 105.8 [23.8] pg/mL; p < 0.01). Additionally, an elevated CGRP level was found to increase the odds of having a FIH [OR = 1.32; 95%CI 1.06-1.22].

CONCLUSIONS

Our findings revealed the role of CGRP in FIHs for the first time and suggest further investigation in signaling pathways downstream CGRP receptors. Furthermore, the modulation CGRP or CGRP receptors could have a clinical application in the prevention of FIHs.

TRIAL REGISTRATION

This study was registered with the Saudi Food and Drug Authority in the Saudi Clinical Trials Registry (SCTR; No. 22122102).

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.

The transition of medication overuse status by acute medication categories in episodic or chronic migraine patients to non-overuse status after receiving anti-CGRP monoclonal antibodies: a systematic review and meta-analysis of phase 3 randomized control trial

OBJECTIVE

The objective of this systematic review and meta-analysis was to determine whether patients with episodic (EM) or chronic migraine (CM), who were treated with anti-CGRP antibodies, showed a reversal from medication overuse (MO) or medication overuse headache (MOH) status at their baseline to non-overuse status. Furthermore, this study aimed to establish which acute headache medication (AHM) categories responded more effectively to anti-CGRP antibodies.

METHODS

A systematic search was conducted in the PubMed database for relevant studies from January 2013 to September 2023. We included phase three randomized controlled trials to examine the role of anti-CGRP antibodies in patients with EM or CM and their MO status. A meta-analysis was conducted to find the association between anti-CGRP antibodies and the number of EM and CM patients with MO or MOH at baseline that reverted to non-MO status or below the MOH threshold.

RESULTS

The initial search yielded a total of 345 studies. After removing duplicates and screening with inclusion criteria, 5 studies fulfilled our conditions. Each study reviewed the response to changes in the MO status of patients after receiving anti-CGRP antibodies, including eptinezumab, fremanezumab, galcanezumab, and erenumab, compared to placebo. Our study analyzed three AHM categories: triptans, simple analgesics, and multiple drugs. The overall relative risk (RR) was 1.44 (95% CI, 1.31 to 1.59; p < 0.001). The RRs for triptans, simple analgesics, and multi-drug groups were 1.71 (95% CI, 1.53 to 1.91; p < 0.001), 1.10 (95% CI, 0.83 to 1.47; p = 0.5), and 1.29 (95%CI 1.14 to 1.46; p < 0.001) respectively.

CONCLUSION

The meta-analysis has shown that anti-CGRP antibodies were statistically significant in transitioning from MO or MOH status to non-MO status or below the MOH threshold (RR = 1.44) for all included studies and all AHM categories except for simple analgesics. Patients from the triptan group had the highest RR of 1.71 with a p-value < 0.001, while the simple analgesics group had an RR of 1.10, however, with a p-value > 0.05. Interestingly, this analysis can be interpreted as that anti-CGRP antibodies might not be effective in reducing simple analgesics use in EM or CM patients. Further studies are needed to investigate these matters.

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.

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.

Meningeal lymphatic vessel dysfunction driven by CGRP signaling causes migraine-like pain in mice

Migraines are a type of headache that occur with other neurological symptoms, but the pathophysiology remains unclear. In this issue of the JCI, Nelson-Maney and authors used constitutive and inducible knockouts of the CGRP receptor components, elegantly demonstrating an essential function of CGRP in modulating meningeal lymphatic vessels (MLVs) in migraine. CGRP was shown to induce rearrangement of membrane-bound gap junction proteins in MLVs, resulting in a reduced CSF flux into cervical lymph nodes. The authors also provided evidence of a primary role for CGRP in modulating neuro-immune function. Finally, by showing that blocking CGRP signaling in MLVs attenuated pain behavior associated with acute migraine in rodents, the authors provided a target for pharmacological blockade of CGRP in relation to primary headache disorders.

Impact of Erenumab on Migraine Disability: A Three-Month MIDAS (Migraine Disability Assessment Scale) Score Analysis at Dubai Health Facilities

BACKGROUND AND AIM

Migraine is a prevalent neurological disorder causing recurrent headaches that significantly impact daily life. Erenumab, a calcitonin gene-related peptide (CGRP) receptor antagonist, has emerged as a promising treatment for migraine. CGRP is thought to play a role in migraine pathophysiology, and erenumab works by blocking CGRP binding to its receptors. Erenumab has been found to be effective in reducing migraine frequency, with potential benefits for improving patient outcomes. This study investigated the impact of erenumab on migraine disability in patients treated at Dubai Health facilities. We specifically assessed changes in Migraine Disability Assessment Scale (MIDAS) scores before and after a three-month treatment period.

METHODS

This retrospective analysis examined data from 26 patients diagnosed with migraine according to the established criteria. All patients received erenumab treatment for three months. MIDAS, a validated tool, was used to quantify migraine-related disability at baseline and after treatment completion. Due to potential skewness in the data distribution, the statistical analysis focused on the median change in MIDAS scores across groups based on gender and erenumab dosage. Non-parametric tests were employed to assess group differences.

RESULTS

Erenumab treatment resulted in a median decrease of 13 points in MIDAS scores, suggesting a potential improvement in migraine disability at three months. Statistical analysis revealed no statistically significant group differences regarding MIDAS score changes between genders or erenumab dosage groups. However, trends toward improvement were observed in all subgroups.

CONCLUSION

While not statistically significant due to the limited sample size and the absence of a control group, these findings suggest a potential benefit of erenumab in reducing migraine disability. Future research with more extensive, controlled trials is warranted to definitively assess erenumab's effectiveness and explore potential treatment regimen variations for optimal patient outcomes.

[CGRP: from neuropeptide to the therapeutic target (background and pathophysiology)]

Calcitonin gene-related peptide (CGRP) plays a pivotal role in migraine pathophysiology. The importance of CGRP in migraine became evident from numerous clinical studies investigating CGRP levels both interictally and ictally and reports on the efficacy of CGRP-based migraine therapies. In this paper, the above mentioned studies will be presented and the reader will be introduced to the development of CGRP-based medication. Finally, current study results on CGRP receptor antagonists, the so-called gepants, will be presented.

Triptans in the Acute Migraine Management of Children and Adolescents: An Update

PURPOSE OF REVIEW

To summarize recent findings regarding triptan use in the acute treatment of pediatric migraine.

RECENT FINDINGS

Prevalence of pediatric migraine is rising. The American Headache Society and American Academy of Neurology updated guidelines to provide evidence-based recommendations for the treatment of acute migraine in youth. In the setting of a dearth of new randomized controlled trials (RCTs), we review current guidelines, triptan use in the emergency department, and an era of secondary analyses. Measuring the efficacy of triptans in pediatric migraine has been challenged by high placebo response rates. Secondary analyses, combining data from multiple RCTs, support that triptans are safe and effective in the treatment of migraine. Triptans are a vital tool and the only FDA-approved migraine-specific treatment available in pediatrics. There is a need for further studies and funding support in pediatric headache medicine.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

INTERPRETATION

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

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

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

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.

Zavegepant for Acute Treatment of Migraine: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

Evaluate the safety and efficacy of zavegepant (BHV-3500), a recently approved nasal spray containing a third-generation calcitonin gene-related peptide receptor antagonist, for treating acute migraine attacks.

METHODS

A comprehensive search was conducted across various databases up to 06/26/2023 to identify relevant randomized clinical trials (RCTs) on zavegepant's efficacy and safety in treatment of acute migraine attacks. Primary outcome: freedom from pain at 2 hours postdose. Safety outcomes were evaluated based on adverse events (AEs), with zavegepant 10 mg and placebo groups compared for incidence of AEs.

RESULTS

Two RCTs, involving 2061 participants (1014 receiving zavegepant and 1047 receiving placebo), were quantitatively analyzed. An additional trial was included for qualitative synthesis. Zavegepant 10 mg exhibited a significantly higher likelihood of achieving freedom from pain at 2 hours postdose compared with the placebo group (risk ratio [RR] 1.54, 95% confidence interval [CI] 1.28 to 1.84). It also showed superior relief from the most bothersome symptoms at 2 hours postdose compared with placebo (RR 1.26, 95% CI 1.13 to 1.42). However, the zavegepant 10 mg group experienced a higher incidence of AEs compared with placebo (RR 1.78, 95% CI 1.5 to 2.12), with dysgeusia being the most reported AE (RR 4.18, 95% CI 3.05 to 5.72).

CONCLUSION

Zavegepant 10 mg is more effective than placebo in treating acute migraine attacks, providing compelling evidence of its efficacy in relieving migraine pain and most bothersome associated symptoms. Further trials are necessary to confirm its efficacy, tolerability, and safety in diverse clinic-based settings with varied patient populations.

Untangling the mess of CGRP levels as a migraine biomarker: an in-depth literature review and analysis of our experimental experience

BACKGROUND

Calcitonin gene-related peptide (CGRP) is the most promising candidate to become the first migraine biomarker. However, literature shows clashing results and suggests a methodological source for such discrepancies. We aimed to investigate some of these methodological factors to evaluate the actual role of CGRP as biomarker.

METHODS

Previous to the experimental part, we performed a literature review of articles measuring CGRP in migraine patients. Using our 399 bio-bank sera samples, we performed a series of experiments to test the validity of different ELISA kits employed, time of sample processing, long-term storage, sampling in rest or after moderate exercise. Analysis of in-house data was performed to analyse average levels of the peptide and the effect of sex and age.

RESULTS

Literature review shows the high variability in terms of study design, determination methods, results and conclusions obtained by studies including CGRP determinations in migraine patients. CGRP measurements depends on the method and specific kit employed, also on the isoform detected, showing completely different ranges of concentrations. Alpha-CGRP and beta-CGRP had median with IQR levels of 37.5 (28.2-54.4) and 4.6 (2.4-6.4)pg/mL, respectively. CGRP content is preserved in serum within the 24 first hours when samples are stored at 4°C after clotting and immediate centrifugation. Storages at -80°C of more than 6 months result in a decrease in CGRP levels. Moderate exercise prior to blood extraction does not modulate the concentration of the peptide. Age positively correlates with beta-CGRP content and men have higher alpha-CGRP levels than women.

CONCLUSIONS

We present valuable information for CGRP measurements in serum. ELISA kit suitability should be tested prior to the experiments. Alpha and beta-CGRP levels should be analysed separately as they can show different behaviours even within the same condition. Samples can be processed in a 24-h window if they have been kept in 4°C and should not be stored for more than 6 months at -80°C before assayed. Patients do not need to rest before the blood extraction unless they have performed a high-endurance exercise. For comparative studies, sex and age should be accounted for as these parameters can impact CGRP concentrations.

Female-selective mechanisms promoting migraine

Sexual dimorphism has been revealed for many neurological disorders including chronic pain. Prelicinal studies and post-mortem analyses from male and female human donors reveal sexual dimorphism of nociceptors at transcript, protein and functional levels suggesting different mechanisms that may promote pain in men and women. Migraine is a common female-prevalent neurological disorder that is characterized by painful and debilitating headache. Prolactin is a neurohormone that circulates at higher levels in females and that has been implicated clinically in migraine. Prolactin sensitizes sensory neurons from female mice, non-human primates and humans revealing a female-selective pain mechanism that is conserved evolutionarily and likely translationally relevant. Prolactin produces female-selective migraine-like pain behaviors in rodents and enhances the release of calcitonin gene-related peptide (CGRP), a neurotransmitter that is causal in promoting migraine in many patients. CGRP, like prolactin, produces female-selective migraine-like pain behaviors. Consistent with these observations, publicly available clinical data indicate that small molecule CGRP-receptor antagonists are preferentially effective in treatment of acute migraine therapy in women. Collectively, these observations support the conclusion of qualitative sex differences promoting migraine pain providing the opportunity to tailor therapies based on patient sex for improved outcomes. Additionally, patient sex should be considered in design of clinical trials for migraine as well as for pain and reassessment of past trials may be warranted.

Dynamic fluctuations of salivary CGRP levels during migraine attacks: association with clinical variables and phenotypic characterization

BACKGROUND

Migraine is a complex neurological disorder with significant heterogeneity in its clinical presentation and molecular mechanisms. Calcitonin gene-related peptide (CGRP) has emerged as a key player in migraine pathophysiology, but challenges remain in its utilization as a biomarker. This study aimed to investigate salivary CGRP levels during migraine attacks across the frequency spectrum and explore associations with clinical variables.

METHODS

A prospective longitudinal pilot study was conducted, recruiting migraine patients from an outpatient headache clinic. Salivary CGRP levels were measured at interictal, onset, post-2 h of onset and end-of-attack. Using generalized linear mixed models, we explored the effect of CGRP changes over the attack in presence of depressive symptoms (DS), acute attack treatment, and after three-months of erenumab treatment. Finally, patients were classified and compared according to their CGRP phenotype.

RESULTS

A total of 44 migraine patients were included (90.9% women), with 80 migraine attacks analyzed. Salivary CGRP levels increased at the onset of migraine attacks. We observed statistically significant interactions between DS and both the linear (Est. [SE]: 19.4 [5.8], p = 0.001) and quadratic terms of time (-19.1 [6.0], p = 0.002). Additionally, a significant three-way interaction within the use of acute treated attack (linear-term: -18.5 [6.2], p = 0.005; quadratic-term: 19.2 [6.8], p = 0.005) was also found. Molecular phenotyping revealed that 72.7% (32/44) of patients presented only CGRP-dependent attacks, while 27.3% (12/44) presented non-CGRP-dependent migraine attacks. Patients with only CGRP-dependent attacks were associated with younger age, shorter disease evolution time, a higher proportion of aura, and fewer monthly headache days (p < 0.05). Exploratory analysis of erenumab treatment effects did not result in changes in CGRP levels during migraine attacks.

CONCLUSIONS

Our study underscores the dynamic nature of migraine at a molecular level and emphasizes the importance of integrating clinical variables, such as depressive symptoms, in understanding its pathophysiology. The identification of distinct migraine subtypes based on CGRP dependence suggests potential opportunities for personalized treatment approaches.

Is calcitonin gene-related peptide (CGRP) the missing link in food histamine-induced migraine? A review of functional gut-to-trigeminovascular system connections

Calcitonin gene-related peptide (CGRP) and histamine plasma concentrations increase during migraine attacks. Both mediators are potent vasodilators, and they have been shown to reciprocally contribute to the release of each other in the trigeminovascular system, possibly driving migraine development. A high-histamine-content diet triggers migraine in patients who have histamine degradation deficiency owing to diaminooxidase (DAO) gene mutations. Therefore, studying functional links between exogenous histamine and CGRP seems promising for the understanding of diet-induced migraine generation. Notably, there is a lack of knowledge about the interplay of the enteric nervous system and the spinal/trigeminal somatosensory system with regard to CGRP and histamine. Based on background evidence, we propose that a functional interconnection between exogenous histamine and CGRP contributes to migraine development.

Associations of type 2 diabetes and the risk of migraine in Chinese populations

AIM

We aimed to explore the relationship between type 2 diabetes mellitus (T2DM) and the incidence rate of migraine in a Chinese population, and analyze the clinical characteristics of migraine patients with T2DM.

METHODS

Data on the study cohort of 9873 individuals were obtained from the China Health and Retirement Longitudinal Study (CHARLS). The incidence rate of migraine from 2015 to 2018 was assessed. The Cox proportional hazards model was used to estimate hazard ratios (HRs) and their 95% confidence intervals (CIs) for the relationship between T2DM and the incidence of migraine. In addition, a cross-sectional study including 168 migraine patients was conducted in Xiamen, China. Migraine patients were grouped according to their T2DM status. Multivariable linear regression models were used to estimate βs and their 95% CIs for the relationship between migraine characteristics and T2DM.

RESULTS

The cumulative incidence rate of migraine from 2015 to 2018 in the T2DM group and control group was 7.26% [6.04%.8.65%] and 8.91% [8.27%.9.58%], respectively. The risk of migraine in patients with T2DM was reduced by 21% (HR 0.79 [0.65;0.95]) compared to patients with no T2DM after adjustment for confounders. The cross-sectional study showed that the presence of T2DM significantly reduced migraine frequency and relieved migraine intensity.

CONCLUSION

This was the first study to validate that T2DM reduced the risk of migraine in a Chinese population cohort. Patients with migraine and T2DM may experience significant relief from their headache symptoms. Carrying out relevant mechanistic research may help to identify new targets for migraine treatment and contribute to further understanding the impact of T2DM or related metabolic disorders on an individual's health.

Pharmacology of erenumab in human isolated coronary and meningeal arteries: Additional effect of gepants on top of a maximum effect of erenumab

BACKGROUND AND PURPOSE

Multiple drugs targeting the calcitonin gene-related peptide (CGRP) receptor have been developed for migraine treatment. Here, the effect of the monoclonal antibody erenumab on CGRP-induced vasorelaxation was investigated in human isolated blood vessels, as well as the effect of combining erenumab with the small molecule drugs, namely rimegepant, olcegepant, or sumatriptan.

EXPERIMENTAL APPROACH

Concentration-response curves to CGRP, adrenomedullin or pramlintide were constructed in human coronary artery (HCA) and human middle meningeal artery (HMMA) segments, incubated with or without erenumab and/or olcegepant. pA2 or pKb values were calculated to determine the potency of erenumab in both tissues. To study whether acutely acting antimigraine drugs exerted additional CGRP-blocking effects on top of erenumab, HCA segments were incubated with a maximally effective concentration of erenumab (3 μM), precontracted with KCl and exposed to CGRP, followed by rimegepant, olcegepant, or sumatriptan in increasing concentrations.

KEY RESULTS

Erenumab shifted the concentration-response curve to CGRP in both vascular tissues. However, in HCA, the Schild plot slope was significantly smaller than unity, whereas this was not the case in HMMA, indicating different CGRP receptor mechanisms in these tissues. In HCA, rimegepant, olcegepant and sumatriptan exerted additional effects on CGRP on top of a maximal effect of erenumab.

CONCLUSIONS AND IMPLICATIONS

Gepants have additional effects on top of erenumab for CGRP-induced relaxation and could be effective in treating migraine attacks in patients already using erenumab as prophylaxis.

Calcitonin gene-related peptide (CGRP) levels in peripheral blood in patients with idiopathic intracranial hypertension and migraine

BACKGROUND

Calcitonin gene-related peptide (CGRP) plays a dominant role in migraine. This prospective study was designed to investigate CGRP levels in patients with idiopathic intracranial hypertension (IIH) and compare the results of migraine patients and healthy controls (HC). As a second objective, CGRP levels obtained from IIH patients defining sustained headache after the resolution of papilledema were compared with those not defining post-IIH headache.

METHODS

Thirty-six patients with IIH, 36 with episodic migraine (EM), 18 with chronic migraine (CM), and 36 HC were included in the study. CGRP levels were studied from blood samples obtained from the antecubital vein by using a commercial ELISA kit.

RESULTS

Serum CGRP levels of the patient groups were significantly higher than the HC (p < 0.001). As compared with controls, both CM (p Adj<0.001) and IIH (p Adj=0.039) had significantly increased levels of CGRP. Levels recorded from EM patients did not differ from the HC (p Adj=0.661). In 16 IIH patients, persistent headache was reported after the normalization of intracranial pressure (ICP). Twenty patients did not report post-IIH headaches. Comparison of serum CGRP levels of these two groups revealed significantly higher CGRP levels in patients with sustained headaches obtained from blood samples both at the initial and control visit (p Adj <0.001).

CONCLUSIONS

CGRP levels of the patient groups were higher than the HC. High levels recorded in patients with IIH indicates the role of CGRP in IIH related headache and even higher levels in patients with sustained headache after normalization of ICP strengthens this finding.

Ubrogepant: Mechanism of action, clinical and translational science

In recent years, the treatment of migraine has experienced a breakthrough in the development of drugs that target the calcitonin gene-related peptide (CGRP) signaling pathway. Monoclonal antibodies against the receptor or ligand have been developed for the preventive treatment of migraine; whereas, orally administered small molecule CGRP receptor antagonists, called gepants, have been developed for both acute and/or preventive treatment. Both modalities have demonstrated safe and effective treatment of migraine, reducing the number of migraine days for patients as well as reducing symptoms and improving patient function and overall quality of life. Here, we provide an abridged review of ubrogepant, an oral CGRP receptor antagonist, approved for the acute treatment of migraine. We briefly summarize the role of CGRP in migraine pathophysiology, describing the mechanism of action of ubrogepant in the context of this pathway, the clinical pharmacology properties and the clinical development and outcomes, including safety, efficacy, pharmacokinetics, and pharmacodynamics, that supported ubrogepant's approval.

Considerations for hormonal therapy in migraine patients: a critical review of current practice

INTRODUCTION

Migraine, a neurovascular headache disorder, is a leading cause of disability worldwide. Within the multifaceted pathophysiology of migraine, hormonal fluctuations play an evident triggering and exacerbating role, pointing toward the need for identification and proper usage of both existing and new hormonal targets in migraine treatment.

AREAS COVERED

With a threefold higher incidence of migraine in women than in men, the authors delve into sex hormone-related events in migraine patients. A comprehensive overview is given of existing hormonal therapies, including oral contraceptives, intrauterine devices, transdermal and subcutaneous estradiol patches, gnRH-agonists, oral testosterone, and 5α reductase inhibitors. The authors discuss their effectiveness and risks, noting their suitability for different patient profiles. Next, novel evolving hormonal treatments, such as oxytocin and prolactin, are explored. Lastly, the authors cover hormonal conditions associated with migraine, such as polycystic ovary syndrome, endometriosis, and transgender persons receiving gender affirming hormone therapy, aiming to provide more personalized and effective solutions for migraine management.

EXPERT OPINION

Rigorous research into both existing and new hormonal targets, as well as the underlying pathophysiology, is needed to support a tailored approach in migraine treatment, in an ongoing effort to alleviate the impact of migraine on individuals and society.

Trigeminal nerve stimulation: a current state-of-the-art review

Nearly 5 decades ago, the effect of trigeminal nerve stimulation (TNS) on cerebral blood flow was observed for the first time. This implication directly led to further investigations and TNS' success as a therapeutic intervention. Possessing unique connections with key brain and brainstem regions, TNS has been observed to modulate cerebral vasodilation, brain metabolism, cerebral autoregulation, cerebral and systemic inflammation, and the autonomic nervous system. The unique range of effects make it a prime therapeutic modality and have led to its clinical usage in chronic conditions such as migraine, prolonged disorders of consciousness, and depression. This review aims to present a comprehensive overview of TNS research and its broader therapeutic potentialities. For the purpose of this review, PubMed and Google Scholar were searched from inception to August 28, 2023 to identify a total of 89 relevant studies, both clinical and pre-clinical. TNS harnesses the release of vasoactive neuropeptides, modulation of neurotransmission, and direct action upon the autonomic nervous system to generate a suite of powerful multitarget therapeutic effects. While TNS has been applied clinically to chronic pathological conditions, these powerful effects have recently shown great potential in a number of acute/traumatic pathologies. However, there are still key mechanistic and methodologic knowledge gaps to be solved to make TNS a viable therapeutic option in wider clinical settings. These include bimodal or paradoxical effects and mechanisms, questions regarding its safety in acute/traumatic conditions, the development of more selective stimulation methods to avoid potential maladaptive effects, and its connection to the diving reflex, a trigeminally-mediated protective endogenous reflex. The address of these questions could overcome the current limitations and allow TNS to be applied therapeutically to an innumerable number of pathologies, such that it now stands at the precipice of becoming a ground-breaking therapeutic modality.

Ratanasampil is more effective than flunarizine in relieving migraine

Aims: Migraine is a common neurological disorder with high incidence in population. This study aimed to investigate the therapeutic efficacy of Tibetan medicine Ratanasampil (RNSP) and to identify the serum biomarkers for diagnosis and response assessment.Materials and methods: We prospectively recruited 108 migraine patients living at high altitude (2,260 m), including 40 patients for RNSP group, 40 patients for flunarizine (FLZ) group, and 28 patients for placebo group. Serum levels of 5-hydroxytryptamine (5-HT), brain-derived neurotrophic factor (BDNF), calcitonin gene related peptide (CGRP), nerve growth factor (NGF) and β-endorphin (β-EP) before and after therapy were measured.Results: In comparison with placebo, both FLZ and RNSP significantly reduced the migraine days, HIT-6 score and verbal rating scale, headache intensity, duration, accompanying symptoms and headache score in four and eight weeks treatment. RNSP showed no significant difference to FLZ in the above parameters after four weeks treatment, but showed significantly better relief after eight weeks treatment. The overall effective rate of RNSP (92.5%) was also significantly higher than FLZ (74.4%, p < 0.05), mainly due to significantly higher ratio of patients with full recovery. The serum levels of biomarkers, including 5-HT, BDNF, NGF and β-EP, significantly elevated after eight weeks of treatment with RNSP, whereas the level of CGRP significantly decreased. The serum level of 5-HT exhibited significantly bigger percentage changes than other markers.Conclusion: In conclusion, RNSP was more effective than FLZ in relieving migraine after eight weeks continuous treatment. Serum 5-HT, BDNF, CGRP, NGF and β-EP were effective markers reflecting the response to RNSP and FLZ therapy.