Potential treatment targets for migraine: emerging options and future prospects

PACAP38-induced migraine attacks are independent of CGRP signaling: a randomized controlled trial

BACKGROUND

Calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide-38 (PACAP38) are key pathogenic drivers of migraine. While CGRP has become the target of several mechanism-based therapies, less is known about PACAP38 signaling in migraine pathogenesis. Previous studies suggest that PACAP38 can modulate CGRP release, but it might also induce migraine attacks via CGRP-independent mechanisms. Whether PACAP38 signaling is independent of and parallel to CGRP signaling has implications for future therapeutic strategies. Here, we aimed to ascertain whether PACAP-38 can mediate migraine attacks independently of CGRP signaling by assessing the ability of eptinezumab to prevent PACAP38-induced migraine attacks.

METHODS

In a double-blind, placebo-controlled, parallel-group study, we randomly allocated adults with migraine without aura to receive either an intravenous infusion of 300-mg eptinezumab or matching placebo (isotonic saline) over 30 min. Two hours post-infusion, all participants were administered PACAP38 intravenously at 10 pmol/kg/min for 20 min. The primary endpoint was the incidence of migraine attacks during the 24-hour observational period post-infusion of eptinezumab or placebo. Key secondary endpoints included between-group differences in incidence of headache, and area under the curve (AUC) for headache intensity scores, diameter of the superficial temporal artery (STA) and facial skin blood flow.

RESULTS

A total of 38 participants were enrolled and completed the study. No difference was observed in the incidence of PACAP38-induced migraine attacks between the eptinezumab (10 [53%] of 19) and placebo (12 [63%] of 19) groups (Fisher's exact test: P = 0.74). Headache of any intensity was reported by 15 (79%) participants in the eptinezumab group, compared with 16 (84%) participants in the placebo group (Fisher's exact test: P > 0.99). The AUC for headache intensity scores did not differ between the two groups during the first 12 h post-infusion of PACAP38 (Mann-Whitney U-test: P = 0.96). No differences were observed in AUC between the eptinezumab and placebo groups with respect to changes in STA diameter and facial skin blood flow (P > 0.05). No serious adverse events occurred.

CONCLUSIONS

Our results suggest that PACAP38 may mediate its signaling independently of CGRP in migraine pathogenesis. Therapies targeting PACAP signaling are thus a promising new avenue for treating migraine.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05635604. Registered on November 15 2022.

Highly Sensitive Assays for detection of headache inducing neuropeptides, Pituitary adenylate cyclase-activating polypeptide (PACAP) and Calcitonin gene-related peptide (CGRP)

Background

Migraine is one of the most disabling diseases that continues to pose a significant societal burden. Although there are now treatment options for people with migraine, it remains challenging to identify them as clinical features are diverse and complex, and there are no validated diagnostic or treatment prediction biomarkers. Identification is based on either diagnostic coding or the use of certain acute headache abortive treatments. However, socioeconomic disparities can contribute to under-diagnosis and under-treatment of migraine. Thus, efforts to find biomarkers to identify individuals with migraine and which variables could explain migraine-related chronification and disability are warranted. We aimed to investigate the levels of migraine inducing neuropeptides; calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) in peripheral blood samples as potential biomarkers of migraine.

Methods

We developed highly sensitive assays for CGRP and PACAP on the MSD S-PLEX assay platform and used them for bioanalysis of preclinical and clinical samples. Wildtype and neuropeptide challenged mice and rats were profiled using the developed assay. To follow-up, commercially obtained plasma samples from healthy controls and migraineurs were initially profiled. Subsequently, we profiled plasma samples from people with migraine (during and after a headache attack and healthy controls. Both MSD S-PLEX assays were transferred to Celerion where they were validated for analysis of clinical samples.

Results

Using the highly sensitive PACAP assay, we were able to reliably measure circulating levels of endogenous and administrated PACAP38in mouse and rat plasma. Additionally, using the highly sensitive CGRP assay, we were able to reliably measure circulating levels of endogenous and administrated CGRP in mouse and rat plasma. Furthermore, in the initial human samples, circulating CGRP and PACAP levels were not significantly different in healthy controls compared to people with migraine patients. However, ≥50% people with migraine showed increased circulating CGRP and PACAP levels during their attack period compared to post attack. Overall, people with migraine showed a 3 - 396% increase in one or both neuropeptides during their attack period compared to post attack. Circulating plasma CGRP and PACAP levels in healthy control subjects were consistent with previously measured levels.

Conclusion

Our highly sensitive PACAP and CGRP assays were successful in measuring circulating levels of endogenous PACAP38 and CGRP in mouse and rat plasma. Our highly sensitive PACAP and CGRP assays were qualified for measurement of human CGRP and PACAP in healthy control and migraine samples. Plasma CGRP and PACAP levels are elevated in migraineurs during an attack period, and the increased plasma neuropeptide levels during an attack may help the differentiation of migraineurs from non-Migraineurs, or amongst people with migraines to help identify the best treatment for each patient.

Sex difference in TRPM3 channel functioning in nociceptive and vascular systems: an emerging target for migraine therapy in females?

Transient Receptor Potential Melastatin 3 (TRPM3) channels are Ca2+ permeable ion channels that act as polymodal sensors of mechanical, thermal, and various chemical stimuli. TRPM3 channels are highly expressed in the trigeminovascular system, including trigeminal neurons and the vasculature. Their presence in dural afferents suggests that they are potential triggers of migraine pain, which is originating from the meningeal area. This area is densely innervated by autonomous and trigeminal nerves that contain the major migraine mediator calcitonin gene-related peptide (CGRP) in peptidergic nerve fibers. Co-expression of TRPM3 channels and CGRP receptors in meningeal nerves suggests a potential interplay between both signalling systems. Compared to other members of the TRP family, TRPM3 channels have a high sensitivity to sex hormones and to the endogenous neurosteroid pregnenolone sulfate (PregS). The predominantly female sex hormones estrogen and progesterone, of which the levels drop during menses, act as natural inhibitors of TRPM3 channels, while PregS is a known endogenous agonist of these channels. A decrease in sex hormone levels has also been suggested as trigger for attacks of menstrually-related migraine. Notably, there is a remarkable sex difference in TRPM3-mediated effects in trigeminal nociceptive signalling and the vasculature. In line with this, the relaxation of human isolated meningeal arteries induced by the activation of TRPM3 channels is greater in females. Additionally, the sex-dependent vasodilatory responses to CGRP in meningeal arteries seem to be influenced by age-related hormonal changes, which could contribute to sex differences in migraine pathology. Consistent with these observations, activation of TRPM3 channels triggers nociceptive sensory firing much more prominently in female than male mouse meninges, suggesting that pain processing in female patients with migraine may differ. Overall, the combined TRPM3-related neuronal and vascular mechanisms could provide a possible explanation for the higher prevalence and even the more severe quality of migraine attacks in females. This narrative review summarizes recent data on the sex-dependent roles of TRPM3 channels in migraine pathophysiology, the potential interplay between TRPM3 and CGRP signalling, and highlights the prospects for translational therapies targeting TRPM3 channels, which may be of particular relevance for women with migraine.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Analysis of Acupoint Selection and Combinations in Acupuncture Treatment of Migraine: A Protocol for Data Mining

Background

Migraine is a prevalent neurological condition that causes significant disability and has a profound impact on sufferers' ability to work and their overall quality of life. The efficacy of acupuncture in the treatment of migraines has been confirmed via extensive clinical research. However, because each acupoint generates various analgesic processes, and different acupuncture physicians select different acupoints, there is still uncertainty regarding the optimal acupoint selection.

Objective

Our purpose is to conduct the initial thorough data mining analysis to determine the optimal acupoint selection and combinations for the treatment of migraines.

Methods

We will conduct a search of eight electronic bibliographic databases (PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wanfang Database, Chinese Biomedical Literature Database, and Chongqing VIP Database) from the inception of the databases to July 2024. Clinical trials that evaluate the efficacy of acupuncture therapy in migraine management will be chosen. Literature will be rigorously reviewed in accordance with inclusion and exclusion criteria, and pertinent data will be extracted for analysis. Excel 2021 will be utilized to conduct descriptive statistics. SPSS Modeler 14.1 will be employed to conduct the association rule analysis. SPSS Statistics 26.0 will be employed to conduct exploratory factor analysis, cluster analysis, and decision tree analysis.

Results

This study aims to investigate the optimal acupoint selection and combinations for people suffering from migraines.

Conclusion

Our research will offer empirical support for the efficacy and possible therapeutic recommendations of acupoint application in treating migraine patients, facilitating collaborative decision-making between physicians and patients.

Neuromodulation treatments for migraine: a contemporary update

PURPOSE OF REVIEW

Neuromodulation approaches have been a part of a revolution in migraine therapies with multiple devices approved or in development. These devices vary in the nerve(s) being targeted, implantable versus noninvasive form factors as well as their effectiveness for acute pain reduction or migraine prevention. This review will summarize these recent advancements and approaches that are being developed which build upon prior work and improved technology that may help enhance the effectiveness as well as the patient experience.

RECENT FINDINGS

Both noninvasive and implantable devices primarily targeting cranial nerves have shown the ability to help alleviate migraine symptoms. Multiple prospective and retrospective studies have demonstrated clinically meaningful reductions in headache intensity with noninvasive approaches, while prevention of migraine demonstrates more modest effects. Implantable neuromodulation technologies focusing on occipital and supraorbital stimulation have shown promise in migraine/headache prevention in chronic migraine patients, but there is a need for improvements in technology to address key needs for surgical approaches.

SUMMARY

Electrical neuromodulation approaches in the treatment of migraine is undergoing a transformation towards improved outcomes with better technologies that may suit various patient needs on a more individualized basis.

PACAP38/mast-cell-specific receptor axis mediates repetitive stress-induced headache in mice

BACKGROUND

Pain, an evolutionarily conserved warning system, lets us recognize threats and motivates us to adapt to those threats. Headache pain from migraine affects approximately 15% of the global population. However, the identity of any putative threat that migraine or headache warns us to avoid is unknown because migraine pathogenesis is poorly understood. Here, we show that a stress-induced increase in pituitary adenylate cyclase-activating polypeptide-38 (PACAP38), known as an initiator of allosteric load inducing unbalanced homeostasis, causes headache-like behaviour in male mice via mas-related G protein-coupled receptor B2 (MrgprB2) in mast cells.

METHODS

The repetitive stress model and dural injection of PACAP38 were performed to induce headache behaviours. We assessed headache behaviours using the facial von Frey test and the grimace scale in wild-type and MrgprB2-deficient mice. We further examined the activities of trigeminal ganglion neurons using in vivo Pirt-GCaMP Ca2+ imaging of intact trigeminal ganglion (TG).

RESULTS

Repetitive stress and dural injection of PACAP38 induced MrgprB2-dependent headache behaviours. Blood levels of PACAP38 were increased after repetitive stress. PACAP38/MrgprB2-induced mast cell degranulation sensitizes the trigeminovascular system in dura mater. Moreover, using in vivo intact TG Pirt-GCaMP Ca2+ imaging, we show that stress or/and elevation of PACAP38 sensitized the TG neurons via MrgprB2. MrgprB2-deficient mice showed no sensitization of TG neurons or mast cell activation. We found that repetitive stress and dural injection of PACAP38 induced headache behaviour through TNF-a and TRPV1 pathways.

CONCLUSIONS

Our findings highlight the PACAP38-MrgprB2 pathway as a new target for the treatment of stress-related migraine headache. Furthermore, our results pertaining to stress interoception via the MrgprB2/PACAP38 axis suggests that migraine headache warns us of stress-induced homeostatic imbalance.