Calcitonin Gene-related Peptide Receptor Research Articles

Crosstalk between bone metastatic cancer cells and sensory nerves in bone metastatic progression.

Although the role of peripheral nerves in cancer progression has been appreciated, little is known regarding cancer/sensory nerve crosstalk and its contribution to bone metastasis and associated pain. In this study, we revealed that the cancer/sensory nerve crosstalk plays a crucial role in bone metastatic progression. We found that (i) periosteal sensory nerves expressing calcitonin gene-related peptide (CGRP) are enriched in mice with bone metastasis; (ii) cancer patients with bone metastasis have elevated CGRP serum levels; (iii) bone metastatic patient tumor samples express elevated calcitonin receptor-like receptor (CRLR, a CGRP receptor component); (iv) higher CRLR levels in cancer patients are negatively correlated with recurrence-free survival; (v) CGRP induces cancer cell proliferation through the CRLR/p38/HSP27 pathway; and (vi) blocking sensory neuron-derived CGRP reduces cancer cell proliferation in vitro and bone metastatic progression in vivo. This suggests that CGRP-expressing sensory nerves are involved in bone metastatic progression and that the CGRP/CRLR axis may serve as a potential therapeutic target for bone metastasis.

Safety and Efficacy of Calcitonin Gene-related Peptide Receptor Antagonists and Selective Serotonin Receptor Agonist in the Management of Migraine: A Systematic Review and Meta-analysis.

Recently, US Food and Drug Administration (FDA) has approved calcitonin gene-related peptide receptor antagonists (rimegepant, and ubrogepant), and selective serotonin receptor agonists (lasmiditan) in the management of migraine. However, the exact safety and efficacy profile of these drugs is unclear so far. The study's primary objective was to determine the exact safety and efficacy profile. The overall estimate was calculated in terms of risk ratios using a suitable model. The subgroup analysis was also performed to check the effect of individual drugs on the outcome, whereas sensitivity analysis was performed to check the effects of outliers on the outcome. All the analyses were performed using Rev Man 5. The drugs have shown significant improvement in efficacy parameters (pain freedom, most bothersome symptoms, phonophobia, nausea, and photophobia). The subgroup analysis results have shown significant improvement in all efficacy parameters in the rimegepant and ubrogepant groups. The effect of ubrogepant on safety parameters was found to be non-significant, indicating a better safety profile of ubrogepant than lasmiditan. The sensitivity analysis results have shown no effect of outliers on the efficacy parameters. Based on the available evidence, recently approved drugs are effective in the treatment of migraine, however, associated with few adverse drug reactions.

Protective role of TRPV1+ nociceptive neurons communication to macrophages against T. cruzi infection in mice

Chagas’ disease is a life-threatening condition caused by Trypanosoma cruzi. Patients with chronic disease may develop gastrointestinal, neurological, or associated neuro-digestive dysfunctions. CNS invasion by T. cruzi can occur in the acute phase, and its presence in the brain and cerebrospinal fluid was reported. T. cruzi induces nociceptor neuron activation and pain. Nociceptive neurons and macrophage interact in diseases, and this neuroimmune communication has a pivotal role in disease outcome. We investigated, the role of TRPV1+ neurons in experimental T. cruzi infection in mice. T. cruzi forms were observed in the DRG and spinal cord in early stages of acute infection, and intrathecal administration of T. cruzi antigens into spinal cord induced pain. Trpv1 mRNA expression was increased in the DRG of infected mice and targeting TRPV1 reduced T. cruzi-induced pain. TRPV1 nociceptor ablation increased blood parasitemia while TRPV1 knockout mice presented 50% mortality upon infection in a normally non-lethal model. TRPV1 knockout also worsened clinical outcomes (hepatomegaly and megacecum), increased plasmatic Th2 cytokines and nitrite in cardiac tissue, and reduced heart leukocyte infiltration. Conditioned media of capsaicin-stimulated DRG neurons decreased macrophage internalization of T. cruzi, and CGRP receptor antagonism in infected mice reduced pain, increased early parasitemia and promoted 18% mortality. This indicates that soluble mediators released upon nociceptor activation such as CGRP increase macrophage ability to control disease outcome. These data unveil TRPV1+ neurons release CGRP to limit macrophage internalization of T. cruzi, triggering protective mechanisms against T. cruzi infection.

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.

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). 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. 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. 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. 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.

Sex differences in expression of CGRP family of receptors and ligands in the rat trigeminal system

BackgroundCalcitonin gene-related peptide (CGRP) is part of the calcitonin peptide family, which includes calcitonin (CT), amylin (AMY), and adrenomedullin (ADM). CGRP and its receptor are highly present in the trigeminovascular system (TVS). Recent research suggests that other members of the calcitonin family could be feasible therapeutic targets in the treatment of migraine. The present study aims to elucidate the distribution of ADM, AMY, CT, and their receptors in the rat TVS, and to explore potential sex differences in their expression.MethodsTrigeminal ganglia (TG) were dissected from male and female adult rats. Protein and gene expression were assessed through immunohistochemistry and RT-qPCR. Additionally, the dura mater was isolated for further investigation of protein expression and fiber localization using immunohistochemistry.ResultsQuantitative gene expression analysis revealed the presence of all genes in male and female TGs, except for calcitonin receptor (CTR). Notably, CGRP mRNA levels in TG were several folds higher than those of other genes. The receptor activity-modifying protein-1 (RAMP1) mRNA levels were significantly higher in female compared to male.No AMY or CT immunoreactivity was observed in the TVS. In contrast, immunoreactivity for ADM, CGRP, RAMP1, CTR, and calcitonin-like receptor (CLR) were observed in the cytoplasm of TG neurons. Immunoreactive Aδ-fibers storing RAMP1, ADM and CLR were also identified. RAMP2 and RAMP3 were expressed in nucleus of TG neurons and in satellite glial cells. Furthermore, RAMP1 and CLR were co-localized with CASPR in the nodes of Ranvier located in Aδ-fibers.ConclusionsThis study provides valuable insights into the distribution of the CGRP family of peptides and their receptors in the TVS. CGRP mRNA levels in the TG were markedly higher than those of other genes, demonstrating the key role of CGRP. The co-localization of CLR and RAMP1 on Aδ-fibers with CASPR suggests a potential role for this receptor in modulating trigeminal nerve function and neuronal excitability, with implications for migraine pathophysiology. Additionally, RAMP1 mRNA levels were significantly higher in female TG compared to males, indicating sex-specific differences in gene expression. These findings underscore the need for further research into the functional significance of gender-related variations.

Effects of multiple-dose administration of zavegepant nasal spray on the single-dose pharmacokinetics of ethinyl estradiol-levonorgestrel.

The potential for drug-drug interaction of multiple-dose intranasal zavegepant on the single-dose oral contraceptive ethinyl estradiol and levonorgestrel (EE-LNG) was evaluated. Zavegepant (as a nasal spray) is a calcitonin gene-related peptide receptor antagonist approved in the United States for treatment of acute migraine in adults. This single-center, Phase 1, open-label, fixed-sequence study included healthy, nonsmoking females (18-45 years old). In treatment Period 1, a single oral dose of EE-LNG 0.02-0.10 mg was administered on Day 1. In treatment Period 2, intranasal zavegepant (20 mg daily; 10 mg per nostril separated by 1 h) was administered on Days 1-5; 1 oral dose of EE-LNG 0.02-0.10 mg was administered immediately after first 10 mg intranasal zavegepant dose on Day 2. Blood samples for EE-LNG concentrations were collected on Day 1, treatment Period 1, and Day 2, treatment Period 2, and zavegepant concentrations on Day 2, treatment Period 2. Noncompartmental pharmacokinetic parameters included maximum observed concentration (Cmax), area under the concentration-time curve (AUC) from Time 0 to last non-zero concentration (AUC0-t), and AUC from Time 0 to infinity (AUC0-inf). The safety and pharmacokinetic sample sizes were 26 and 23, respectively. Statistical comparisons of pharmacokinetic exposure parameters after co-administration of zavegepant and EE-LNG versus EE-LNG alone showed small, but statistically insignificant, changes in either EE or LNG exposure. EE comparison ratios (90% confidence intervals [CIs]) were 109.9% (105.3%, 114.8%) for AUC0-inf and 110.2% (104.6%, 116.1%) for Cmax. LNG comparison ratios (90% CIs) were 107.0% (100.2%, 114.3%) for AUC0-inf and 108.8% (99.9%, 118.4%) for Cmax. Frequently reported treatment-emergent adverse events included dysgeusia (n = 25, 96%), throat irritation (n = 11, 42%), headache (n = 10, 39%), nasal discomfort (n = 7, 27%), pharyngeal paresthesia (n = 5, 19%), and nausea (n = 4, 15%). Co-administration of zavegepant nasal spray with a single dose of an oral contraceptive resulted in no clinically meaningful changes (<12% increase) in EE-LNG exposure.

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.

Upregulation of NGF/TrkA-Related Proteins in Dorsal Root Ganglion of Paclitaxel-Induced Peripheral Neuropathy Animal Model.

Paclitaxel (PTX) can induce chemotherapy-induced peripheral neuropathy (CIPN) as a side effect. The aim of this study was to understand the neurochemical changes induced by NGF/TrkA signaling in PTX-induced neuropathic pain. The PTX-induced CIPN mouse model was evaluated using nerve conduction velocity (NCV) and behavioral tests. Protein expression in mouse DRG was observed by Western blotting and immunohistochemistry. Nerve growth factor (NGF), IL-6, and IL-1β mRNA levels were determined using qRT-PCR by isolating total RNA from whole blood. PTX showed low amplitude and high latency values in NCV in mice, and induced cold allodynia and thermal hyperalgesia in behavioral assessment. Activating transcription factor 3 (ATF3) and MAPK pathway related proteins (ERK1/2), tropomyosin receptor kinase A (TrkA), calcitonin gene related peptide (CGRP) and transient receptor potential vanilloid 1 (TRPV1) were upregulated 7th and 14th days after 2 mg/kg and 10 mg/kg of PTX administration. Protein kinase C (PKC) was upregulated 7th days after 10 mg/kg PTX treatment and 14th days after 2 mg/kg and 10 mg/kg PTX administration. NGF, IL-6, and IL-1β fold change values also showed a time- and dose-dependent increase. Taken together, our findings may improve our understanding of the nociceptive symptoms associated with PTX-induced neuropathic pain and lead to the development of new treatments for peripheral neuropathy.

Novel Calcitonin Gene-Related Peptide (CGRP) Interfering Migraine Therapies and Stroke-A Review.

Migraine and stroke are neurological disorders with significant global prevalence and impact. Recent advances in migraine therapy have focused on the calcitonin gene-related peptide (CGRP) pathway. This review examines the shared pathomechanisms between migraine and stroke, with emphasis on the role of CGRP. We analyze the current literature on CGRP's functions in cerebrovascular regulation, edema formation, neuroinflammation, and neuroprotection. CGRP acts as a potent vasodilator and plays a crucial role in trigeminovascular activation during migraine attacks. In stroke, CGRP has demonstrated neuroprotective effects by improving collateral circulation and reducing ischemia-reperfusion injury. Concerns have been raised about the potential impact of CGRP inhibitors on stroke risk and outcomes. Studies in animals suggest that CGRP receptor antagonists may worsen cerebral ischemia by impairing collateral flow. We discuss the implications of these findings for the use of CGRP-targeting therapies in migraine patients, especially those at increased risk of stroke. Additionally, we explore the complex interplay between CGRP, endothelial function, and platelet activity in both conditions. This review highlights the need for further research to elucidate the long-term cerebrovascular safety of CGRP pathway inhibitors and to identify potential subgroups of migraine patients who may be at higher risk of adverse cerebrovascular events with these novel therapies.

Extracellular bimolecular fluorescence complementation for investigating membrane protein dimerization: a proof of concept using class B GPCRs.

Bimolecular fluorescence complementation (BiFC) methodology uses split fluorescent proteins to detect interactions between proteins in living cells. To date, BiFC has been used to investigate receptor dimerization by splitting the fluorescent protein between the intracellular portions of different receptor components. We reasoned that attaching these split proteins to the extracellular N-terminus instead may improve the flexibility of this methodology and reduce the likelihood of impaired intracellular signal transduction. As a proof-of-concept, we used receptors for calcitonin gene-related peptide, which comprise heterodimers of either the calcitonin or calcitonin receptor-like receptor in complex with an accessory protein (receptor activity-modifying protein 1). We created fusion constructs in which split mVenus fragments were attached to either the C-termini or N-termini of receptor subunits. The resulting constructs were transfected into Cos7 and HEK293S cells, where we measured cAMP production in response to ligand stimulation, cell surface expression of receptor complexes, and BiFC fluorescence. Additionally, we investigated ligand-dependent internalization in HEK293S cells. We found N-terminal fusions were better tolerated with regards to cAMP signaling and receptor internalization. N-terminal fusions also allowed reconstitution of functional fluorescent mVenus proteins; however, fluorescence yields were lower than with C-terminal fusion. Our results suggest that BiFC methodologies can be applied to the receptor N-terminus, thereby increasing the flexibility of this approach, and enabling further insights into receptor dimerization.

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

BackgroundFasting-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.MethodsAs 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.ResultsPlasma 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].ConclusionsOur 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 registrationThis study was registered with the Saudi Food and Drug Authority in the Saudi Clinical Trials Registry (SCTR; No. 22122102).

Neuropeptide signalling orchestrates T cell differentiation.

The balance between T helper type 1 (TH1) cells and other TH cells is critical for antiviral and anti-tumour responses1-3, but how this balance is achieved remains poorly understood. Here we dissected the dynamic regulation of TH1 cell differentiation during in vitro polarization, and during in vivo differentiation after acute viral infection. We identified regulators modulating T helper cell differentiation using a unique TH1-TH2 cell dichotomous culture system and systematically validated their regulatory functions through multiple in vitro and in vivo CRISPR screens. We found that RAMP3, a component of the receptor for the neuropeptide CGRP (calcitonin gene-related peptide), has a cell-intrinsic role in TH1 cell fate determination. Extracellular CGRP signalling through the receptor RAMP3-CALCRL restricted the differentiation of TH2 cells, but promoted TH1 cell differentiation through the activation of downstream cAMP response element-binding protein (CREB) and activating transcription factor 3 (ATF3). ATF3 promoted TH1 cell differentiation by inducing the expression of Stat1, a key regulator of TH1 cell differentiation. After viral infection, an interaction between CGRP produced by neurons and RAMP3 expressed on T cells enhanced the anti-viral IFNγ-producing TH1 and CD8+ T cell response, and timely control of acute viral infection. Our research identifies a neuroimmune circuit in which neurons participate in T cell fate determination by producing the neuropeptide CGRP during acute viral infection, which acts on RAMP3-expressing T cells to induce an effective anti-viral TH1 cell response.

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

BackgroundDifferent 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.MethodsRNA 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.ResultsCalcitonin-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.ConclusionBased 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.

Calcitonin gene-related peptide promotes epithelial reparative and anti-colitic functions of IL-4 educated human macrophages.

Interleukin-4 activated human macrophages (M(IL4) promote epithelial wound healing and exert an anti-colitic effect in a murine model. Blood monocyte-derived M(IL4)s from healthy donors and individuals with Crohn's disease had increased mRNA expression of the calcitonin gene-related peptide (CGRP) receptor chain, RAMP1, raising the issue of neural modulation of the M(IL4)s reparative function. Thus, human (MIL4)s were treated with CGRP and the cells phagocytotic, epithelial wound repair and anti-colitic functions were assessed. Initial studies confirmed up-regulation of expression of the CGRP receptor, which was localized to the cell surface and was functional as determined by CGRP-evoked increases in cAMP. M(IL4,CGRP)s had increased mannose receptor (CD206) and FcgRIIa (CD32a) mRNA expression, a subtle, but significant increase in phagocytosis, and decreased chemokine production following exposure to E. coli. When delivered systemically (106 cells, ip.) to oxazolone-treated rag1-/- mice, M(IL4,CGRP) had an anti-colitic effect superior to M(IL4)s from the same blood donor. Conditioned medium (CM) from M(IL4,CGRP) had increased amounts of TGFb and increased wound-healing capacity compared to matched M(IL4)-CM in the human CaCo2 epithelial cell line in vitro wounding assay. Moreover, M(IL4,CGRP)s displayed increased cyclooxygenase (COX)-1 and prostaglandin D2, and CM from M(IL4,CGRP)s treated with indomethacin or SC-560 to inhibit COX1 activity failed to promote repair of wounded CaCo2 cell monolayers. These data confirm the human M(IL4)s' anti-colitic effect that was enhanced by CGRP, and may be partially dependent on macrophage COX1/PDG2 activity. Thus, input from neurone-derived molecules is a local modifier capable of boosting the anti-colitic effect of autologous M(IL4) transfer.

Cerebral Artery Vasoconstriction After Galcanezumab Loading Dose for Migraine Prevention: A Case Report.

Anti-calcitonin gene-related peptide (CGRP) monoclonal antibodies that target CGRP ligands or receptors, may cause a very rare side effect of reversible cerebral vasoconstriction syndrome (RCVS). This study is a case report of a patient who developed cerebral artery vasoconstriction documented on serial brain magnetic resonance angiography (MRA) scans without the typical manifestations of RCVS following galcanezumab loading dose. Case report: A 40-year-old female patient with high-frequency episodic migraine with visual aura on topiramate 100mg/day developed transient numbness of the right upper and lower extremities and right face without headache and a normal neurological examination 10min after a loading dose of galcanezumab, which resolved over the next 2days. Magnetic resonance angiography brain imaging showed segmental arterial constriction of both middle cerebral arteries in the M1-2 segments and both posterior cerebral arteries in the P1-2 segments, which partial resolved in a subsequent study by the end of 6months. There were no other supporting examination data, such as transcranial Doppler, which might provide additional information on the progression and improvement of the vasoconstriction. Her differential diagnosis included prolonged migraine sensory aura without headache, RCVS, or cerebral vasoconstriction secondary to the effect of an anti-CGRP monoclonal antibody. Further research needs to be conducted.

Characterization of rimegepant drug-drug interactions using the cytochrome P450 probe drugs, itraconazole, rifampin, fluconazole, and midazolam.

Reported here are the results of four rimegepant phase I studies, in healthy participants, aimed at determining the invivo potential of rimegepant (75 mg) for cytochrome P450 (CYP) 3A4-related drug-drug interactions (DDIs). Rimegepant orally disintegrating tablet (Pfizer Inc., New York, NY, USA) is a calcitonin gene-related peptide receptor antagonist approved for acute treatment of migraine and preventive treatment of episodic migraine. People with migraine commonly use multiple drug treatments, with the potential for DDIs. Each study was an open-label, single-arm, single-sequence, crossover study. Rimegepant was tested as a victim drug by separate co-administration of itraconazole (a strong CYP3A4 inhibitor and P-glycoprotein inhibitor) in Study 1, rifampin (a strong CYP3A4 inducer and moderate CYP2C9 inducer) in Study 2, and fluconazole (a strong CYP2C9 inhibitor and moderate CYP3A4 inhibitor) in Study 3, and as a perpetrator drug by co-administration with midazolam (a CYP3A4 substrate) in Study 4. Mean values of single-dose rimegepant maximum concentration (Cmax) and area under the curve from time 0 to infinity (AUC0-inf) increased with itraconazole co-administration (n = 22) by 1.42-fold (90% confidence interval [CI] 1.25-1.61) and by 4.14-fold (90% CI 3.87-4.44), respectively, and decreased with rifampin co-administration (n = 21) to 36% (90% CI 31.2-41.4%) and to 19% (90% CI 16.3-21.4%), respectively. Co-administration with fluconazole (n = 23) increased rimegepant mean AUC0-inf by 1.80-fold (90% CI 1.68-1.93), with no impact on Cmax (1.04-fold; 90% CI 0.94-1.15). Co-administration of rimegepant single dose (300 mg; n = 14) or multiple doses (150 mg/day; n = 14) increased the mean Cmax of midazolam by 1.38-fold (90% CI 1.13-1.67) and 1.53-fold (90% CI 1.32-1.78), respectively, and the AUC0-inf of midazolam by 1.86-fold (90% CI 1.58-2.19) and 1.91-fold (90% CI 1.63-2.25), respectively. Based on the magnitude of DDIs, these studies indicate the following: co-administration of rimegepant with a strong CYP3A4 inhibitor should be avoided; during co-administration with a moderate CYP3A4 inhibitor, another dose of rimegepant within 48 h should be avoided; co-administration of rimegepant with a strong or moderate CYP3A4 inducer should be avoided; CYP2C9 does not play a meaningful role in rimegepant metabolism; and there is no clinically meaningful CYP3A4 inhibition by rimegepant.

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

To evaluate the pharmacodynamic (PD) and pharmacokinetic (PK) interactions between zavegepant and sumatriptan in healthy adults. Zavegepant is a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist administered as a nasal spray approved in the United States for the acute treatment of migraine. Triptans, including sumatriptan, are a different class of drugs for acute migraine treatment and are associated with a risk of increased blood pressure (BP). Hence, it is important to study the drug-drug interactions between zavegepant and sumatriptan due to potential coadministration in clinical settings. This was a Phase 1, single-center, partially blind, randomized, placebo-controlled, single-arm study. Eligible participants were males aged ≥ 18 and ≤ 40 years or females aged ≥ 18 and ≤ 50 years. On Day 1, participants received sumatriptan 2 × 6 mg subcutaneous injections (1 h apart) and were then randomized (6:1 ratio) to receive zavegepant 2 × 10 mg nasal spray (1 in each nostril) or placebo on Days 2 and 3. On Day 4, zavegepant or placebo was coadministered with sumatriptan after the second sumatriptan injection. BP, PK, and safety were evaluated at pre-specified time points. Forty-two participants enrolled in the study received at least one dose of any treatment and were included in the safety analyses. Forty-one participants who completed the study were included in the BP and PK analyses. The mean (standard deviation) time-weighted average (TWA) of mean arterial pressure (MAP [sumatriptan+ zavegepant 87.2 (6.8) vs. sumatriptan 86.9 (6.0)]), diastolic BP (DBP [sumatriptan + zavegepant 72.3 (6.8) vs. sumatriptan 72.1 (6.2)]), and systolic BP (SBP [sumatriptan + zavegepant 116.8 (10.2) vs. sumatriptan 116.2 (8.6)]) did not change following zavegepant and sumatriptan coadministration on Day 4 compared to sumatriptan alone on Day 1. Statistical comparisons of the TWA of MAP, DBP, and SBP between sumatriptan and zavegepant coadministration and sumatriptan alone were similar; the differences observed were 0.04 mmHg for MAP (90% confidence interval [CI]: -0.69, 0.77 mmHg), 0.00 mmHg for DBP (90% CI: -0.76, 0.76 mmHg), and 0.33 mmHg for SBP (90% CI: -0.97, 1.63 mmHg). Sumatriptan PK after sumatriptan and zavegepant coadministration versus sumatriptan alone was similar; the comparison ratios were 102.5% (90% CI: 100.7%, 104.2%) for AUC0-inf and 104.1% (90% CI: 98.0%, 110.6%) for Cmax. A small difference in zavegepant PK exposure after sumatriptan and zavegepant coadministration versus zavegepant alone was not considered clinically relevant: the comparison ratios were 112.4% (90% CI: 103.4%, 122.3%) for AUC0-24 and 96.7% (90% CI: 88.9%, 105.2%) for Cmax. Overall, 90% (38/42) of participants experienced ≥ 1 treatment-emergent adverse event that was mild or moderate in severity. All treatments were generally safe and well tolerated. Coadministration of zavegepant with sumatriptan was safe and without PD or PK interactions in healthy adults.

Efficacy of eptinezumab in non-responders to subcutaneous monoclonal antibodies against CGRP and the CGRP receptor: A retrospective cohort study.

Migraine patients unresponsive to calcitonin gene-related peptide (CGRP)(-receptor, -R) monoclonal antibodies (mAbs) may benefit from switching between CGRP(-R) mAbs. However, some patients do not tolerate or respond to any subcutaneous mAbs. This study evaluates the efficacy of the intravenous CGRP mAb eptinezumab in these therapy-refractory patients. In this retrospective cohort study, patients with migraine who previously failed erenumab and at least one CGRP mAb (fremanezumab and/or galcanezumab) received eptinezumab 100 mg, followed by a second dose of 100 mg or 300 mg after 12 weeks. Monthly headache days, monthly migraine days, acute medication days, and migraine pain intensity were recorded from standardized headache diaries during the four weeks before the first infusion (baseline), and during weeks 9-12 and 21-24 of treatment. Patient-reported outcomes were analyzed at baseline, weeks 12, and 24. From January 2023 to February 2024, 41 patients received eptinezumab 100 mg. Of these, 38 (93%) received a second infusion after 12 weeks, with 29 (71%) increasing the dose to 300 mg. The percentage of patients with a ≥30% reduction rate in monthly migraine days was 23.1% at week 12 and 29.7% at week 24. Monthly migraine days decreased from 16.3 ± 8.0 at baseline to 15.4 ± 8.1 days during weeks 9-12 and 14.4 ± 8.0 days during weeks 21-24 (p = 0.07). During weeks 21-24, 38.5% reported a clinically meaningful reduction in HIT-6 scores and 52.4% in MIDAS scores. No adverse events were reported. Eptinezumab may be an effective and well-tolerated option for some treatment-refractory migraine patients unresponsive to subcutaneous CGRP-(R) mAbs.

Elucidation of neuronal activity in mouse models of temporomandibular joint injury and inflammation by in vivo GCaMP Ca2+ imaging of intact trigeminal ganglion neurons.

Patients with temporomandibular disorders (TMDs) typically experience facial pain and discomfort or tenderness in the temporomandibular joint (TMJ), causing disability in daily life. Unfortunately, existing treatments for TMD are not always effective, creating a need for more advanced, mechanism-based therapies. In this study, we used in vivo GCaMP3 Ca2+ imaging of intact trigeminal ganglia (TG) to characterize functional activity of the TG neurons in vivo, specifically in mouse models of TMJ injury and inflammation. This system allows us to observe neuronal activity in intact anatomical, physiological, and clinical conditions and to assess neuronal function and response to various stimuli. We observed a significant increase in spontaneously and transiently activated neurons responding to mechanical, thermal, and chemical stimuli in the TG of mice with TMJ injection of complete Freund adjuvant or with forced mouth opening (FMO). An inhibitor of the calcitonin gene-related peptide receptor significantly attenuated FMO-induced facial hypersensitivity. In addition, we confirmed the attenuating effect of calcitonin gene-related peptide antagonist on FMO-induced sensitization by in vivo GCaMP3 Ca2+ imaging of intact TG. Our results contribute to unraveling the role and activity of TG neurons in the TMJ pain, bringing us closer to understanding the pathophysiological processes underlying TMJ pain after TMJ injury. Our study also illustrates the utility of in vivo GCaMP3 Ca2+ imaging of intact TG for studies aimed at developing more targeted and effective treatments for TMJ pain.

Mass balance and pharmacokinetic characterization ofzavegepant in healthy male subjects.

Zavegepant, a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist, is approved as a nasal spray for acute treatment of migraine in adults. This phase I, open-label, single-center, single-period, nonrandomized study in six healthy male subjects assessed mass balance recovery after a single 15-min intravenous (IV) infusion dose of carbon-14 ([14C])-zavegepant. Blood, urine, and fecal samples were collected over 192 h for analysis of zavegepant in plasma and urine; total radioactivity (TR) in plasma, whole blood, urine, and feces; and zavegepant metabolite profiling and structural identification in plasma, urine, and feces. An average of 96.6% of radioactivity administered was recovered in excreta. Most TR (mean 84.9%) was recovered in the feces, indicating that biliary/fecal elimination was the main route. Volume of distribution of zavegepant based on the terminal phase (129 L) was higher than total body water (42 L), indicating substantial distribution into tissue. Total plasma clearance of zavegepant (220 mL/min) is identical to whole blood clearance given the blood/plasma partition ratio of 1, lower than typical hepatic blood flow (1450 mL/min). The observed plasma terminal half-life of zavegepant was 6.8 h. Exposure to zavegepant accounted for ~90% of circulating plasma TR, suggesting that very low levels of uncharacterized circulating metabolites were present. Metabolite profiling did not identify any metabolites representing ≥10% of radioactivity in plasma, urine, or feces. A single IV infusion of 5 mg [14C]-zavegepant was well tolerated in healthy male subjects. Disposition findings of IV [14C]-zavegepant are applicable to the disposition of the approved zavegepant nasal spray.